Pharmaceutical Microbiology Unit 1 PDF

UNIT- I (CHAPTER-1) INTRODUCTION OF MICROBIOLOGY Points to be covered in this topic 1. INTRODUCTION 2. HISTORY OF MICROBIOLOGY 3. BRANCHES OF MICROBIOLOGY 4. SCOPESOF MICROBIOLOGY 5. IMPORTANCE &APPLIC...

UNIT- I (CHAPTER-1) INTRODUCTION OF MICROBIOLOGY Points to be covered in this topic 1. INTRODUCTION 2. HISTORY OF MICROBIOLOGY 3. BRANCHES OF MICROBIOLOGY 4. SCOPESOF MICROBIOLOGY 5. IMPORTANCE &APPLICATION OF MICRO. OINTRODUCTION Microbiology is the study of microorganisms that is the organism which are of microscopic dimensions. These organisms are too small to be clearty perceived by the unaided human eye. Microorganisms are living organisms that are usually too small to be seen clearly with the naked eye. An organism with a diameter of 1 mm or less are microorganisms and fall into the broad domain of microbiology. At present there is general agreement to include five major groups as microorganísms. The subdivisions are : Mierobiolgy Virology Bacteriology Mycology Phycology Protozoology (Viruses) (Bacteria) (Fungi) (Algae) (Protozoa)  Microorganisms are relevant to all of us in a multitude of ways. The influence of microorganism in human life is both beneficial as well as detrimental also. For example microorganisms are required for the production of bread, cheese, yogurt, alcohol, wine, beer, antibiotics. (e.g. Penicillin, Streptomyin, Chloromycetin), vaccines, vitamins, enzymes and many more important products. Microorganisms are indispensable components of our ecosystem. Microorganism play an important role in the recycling of organic and inorganic material through their roles in the C, N and S cycles, thus playing an important part in the maintenance of the stability of the biosphere.. They are also the source of nutrients at the base of all ectotropical food chains and webs. In many ways all other forms of life depend on the microorganisms. Environment (soil, hydrosphere, anim al, plant) Environmental Biofilm adaptatlon Microbe-animal/plant interactions Intercellular Interactions Bacterlal Populatlon Soclallty &Specificlty of roles Membrane Veslcles (MVa) Intracommunity heterogenelty  MAOREIELDS OF MICROBIOLOGY FIELD DESCRIPTION Algology, Phycology Study of algae Bacteriology Study of bacteria Virology Study of viruses and viral diseases. Protozoology Study of protozoans (animal like single celled eukaryotic organisms). Mycology Study of fungi (achlorophyllous, heterotrophic, eukaryotic with a rigid cell wall containing chitin/cellulose) Parasitology Study of parasitism and parasites (include pathogenic protozoa, helminthes worms and certain insects). Nematology The study of nematodes. Microbial ecology Study of interrelationships between microbes and environment. Microbial morphology Study of detailed structure of microorganism. Microbial taxonomy Concerne d with classification, naming and identification of microorganism. Microbial Physiology Study of metabolism of microbes at cellular and molecular levels. Microbial genetics and Study of genetic material, structure and function and Molecular Biology biochemical reactions of microbial cells involved in metabolism and growth. The branch microbiology has two major aspects: the theoretical and the applied. Doctors and farmers are applied microbiologist. For example the doctors has the primary interest to keep people healthy through the use of scientific knowledge while the scientist (theoretical) work is to obtain new information in his related field and guide the farmers to increase crop yield. Mlcroblology Appled Theoritlcal Medicine Agriculture Mechanisa ldentification  FIELDS OFAPPLJEDMICROBIOLOGY FIELD APPLIED AREAS Air Microbiology Deals with the role of aerospora in contamination and spolage of food and dissemination of plant and animal diseases through afr. Agricultural Study of relationships of microbes and crops and on control of Microbiology plant diseases and improvement of yields. Aquatic Study of microorganisms found in fresh estuarine and marine Microbiology waters. Biotechnology Sclentifîc manipulation of living organisms especially at molecular and genetic level to produce useful products. Dairy Deals with production and maintenance in quality control of Microbiology dairy products. Exomicrobiology Deals with exploration for microbial life in outer space. Medical Causative agents of disease, diagnostic procedure for Microbiology identification of causative agents, preventive measures. Food Microbiology Deals with interaction of microorganisms and food in relaton to food' processing, food spoilage. food borne disease and their prevention Industrial Concerned with industrial uses of microbes in production of Microbiology alcoholic beverages, vitamins, NH,-acids, enzymes, antiblotics and other drugs. Immunology Deals with the immune system that protects against Infection and to study serology reactions. Public Health Concerns with monitoring, control and spread of diseases in Microbiology communities. Harmful Microorganisms Disease and decay are neither inherent properties of organic objects, nor are caused by physical damage, it is microorganisms that bring about these changes. We are surrounded by bacteria, virus, and fungi. Many microorganisms cause diseases in cattle, crops and others are known for entering human bodies and causingvarious diseases. Examples of familiar human diseases are: Bacteria: pneumonia, bacterial dysentery, diphtheria, bubonic plague, meningitis, typhoid, cholera, salmonella, meningococcal. Virus: Chickenpox, measles, mumps, German measles, colds, warts, cold sores, influenza. Protozoa: amoebic dysentery, malaria, Fungi: Ringworm, Athlete's foot. Earthworm Bacteria Useful-Microorganisms Fungi As decomposers, bacteria and fungi play an important role in an ecosystem. They break down dead or waste organic matter and release inorganic molecules. Green plants take these nutrients which are in turn consumed by animals, and the products of these plants and animals are again broken down by decomposers. Yeast is a single-celled fungus that lives naturally on the surface of the fruit. It is economically important in bread-making and brewing beer and also in the making of yoghurt. Most microorganisms are unicellular; if they are multicellular, they lack highly differentiated tissues. There fundamentally two different types of cells, One being Prokaryotic and the other Eukaryotic. Microbes especially prokaryotes are numerous in number in comparison to eukaryotes. The lineage of life on Earth originated from these microbes: 1. Bacteria 2. Archaea 3. Eucarya O HISTORY OF MICROBIOLOGY Physics began in ancient times, mathematics even earlier, but the knowledge of tiny living things, their biology, and their impact on human lives have only been around since the late 19th century. Until about the 1880s, people sill believed that life could form out of thin air and that sickness was caused by sins or bad odors. Opinions about why diseases aflicted people differed between cultures and parts of society and the treatments differed as well. Diseases were thought to be caused by Bad smells, treated by removing or masking the offending odor V An imbalance in the humor of the body, treated with bleeding sweating, and vomiting Y Sins of the soul, treated with prayer and rituals Although the concept of contagion was kmown, it wasn't attributed to tiny living creatures but to bad odors or spirits, such as the devil. Varo and Columella in the first century BC postulated that diseases were caused by invisible beings (Animalia minuta) inhaled or ingested. Fracastorius of Verona (1546) proposed a Contagium vivum as a possible cause of infections disease and Von Plenciz (1762) suggested that each disease was caused by a separate agent. DISCOVERY OEMICROBESAND THE DAWNOE MICROBIOLOGY Microbiology is the study of living organisms of microscopic size. The term microbiology was given by French chemist Louis Pasteur (1822-95). Microbiology is said to have its roots in the great expansion and development of the biological sciences that took place after 1850. The term microbe was first used by Sedillot (1878). The discovery of microbiology as a discipline could be" traced along the following historical eras: Discovery Transition Golden In 20th Century: Era Period Age Era of Molecular Biology The Discovery Era Robert Hooke, a 17th-century English scientist,was the first to use a lens to observe the smallest unit of tissues he called "cells" Soon after; the Dutch amateur biologist Anton van Leeuwenhoek observed what he called "animalcules" with the use of his homemade microscopes. Antonie van Leeuwenhoek (1632-1723) of Delft, Holland (Netherland) was the first person to observe and accurately describe microorganisms (bacteria and protozoa) called 'animalcules' (little animals) in 1676. Actually he was a Dutch linen merchant but spent much of his spare time constructing simple microscopes composed of double convex lenses held between two silver plates. He constructed over 250 small powerful microscopes that could magnify around 50-300 times. Leeuwen hoek Leeuwenhoek was the first person to produce Microscope (circa late 1600s) precise and correct descriptions of bacteria and protozoa using a microscope he made himself. Because of this extraordinary contribution to microbiology, Antonie van Leeuwenhoek is considered as the "Father of microbiology". Antonie van Leeuwenhoek is also considered to be the father of bacteriology and protozoology (protistology). He wrote over 200 letters which were transnmitted as a series of letters from 1674-1723 to Royal Society in London during a 50 years period.  Transition Period When microorganisms were known to exist, most scientists believed that such simple life forms could surely arise through spontaneous generation. That is to say life was thought to spring spontaneously from mud and lakes or anywhere with sufficient nutrients. This concept was so compelling that it persisted until late into the 19th century. The main aspects were to solve the controversy over a spontaneous generation which includes experimentation mainly of Francesco Redi, John Needham, Lazzaro Spallanzani and Nicolas Appert,etc, and to know the disease transmission which mainly includes the work of Ignaz Semmelweis and John Snow. Francesco Redi (1626-1697): The ancient belief in spontaneous generation was first of all challenged by Redi, an Italian physician, who carried out a series of experiments on decaying meat and its ability to produce maggots spontaneously. John Needham (1713-1781) : He was probably the greatest supporter of the theory of spontaneous generation. He proposed that tiny organisms the animalcules arose spontaneously on his mutton gravy. He covered the flasks with cork as done by Redi and even heated some flasks. Still the microbes appeared on mutton broth. Lazzaro Spallanzani (1729-1799): He was an Italian Naturalist who attempted to refute Needham's experiment. He boiled beef broth for longer period, removed the air from the flask and then sealed the container: Followed incubation no growth was observed by him in these flasks. He showed that the heated nutrients could still grow animalcules when exposed to air by simply making a small crack in the neck Thus Spallanzani disproved the doctrine of spontaneous generation. Nicolas Appert followed the idea of Spallanzani's work. He was a French wine maker who showed that soups and liquids can be preserved by heating them extensively in thick champagine bottles. Ignaz Semmelweis and John Snow were the two persons who showed a growing awareness of the mode of disease transmission. Two German scholars Schulze (1815-1873) and Theodor Schwan (1810-1882) viewed that air was the source of microbes and sought to prove this by passing air through hot glass tubes or strong chemicals into boiled infusions in flasks. The infusion in both the cases remained free from the microbes. George Schroeder and Theodor Von Dusch (1854) were the first to introduce the idea of using cottonplugs for plugging microbial culture tubes. Darwin (1859) in his book, 'Origin of the Species' showed that the human body could be conceived as a creature susceptible to the laws of nature. He was of the opinion that disease may be a biological phenomenon, rather than any magic.  The Golden Age The Golden age of microbiology began with the work of Louis Pasteur and Robert Koch who had their own research LMICROBIOLOGY institute. More important there was an acceptance of their work by the scientific community throughout the world and a willingness to continue and expand the work. During this period, we see the real beginning of microbiology as a discipline of biology. The concept of spontaneous generation was finally put to rest by the French chemist Louis Pasteur in an inspired set of experiments involving a goose necked flask. When he boiled broth in a flask with a straight neck and left it exposed to air, organisms grew. Louis Pasteur When he did this with his goose-necked flask, nothing grew. The S-shape of this second flask trapped dust particles from the air, preventing them from reaching the broth. By showing that he could allow air to get into the flask but not the particles in the air, Pasteur proved that it was the organisms in the dust that were growing in the broth. º Pasteur, thus in 1858 fnally resolved the controversy of spontaneous generation versus biogenesis and proved that microorganisms are not spontaneously generated from inanimate matter but arise from other microorganisms. He also found that fermentation of fruits and grains, resulting in alcohol, was brought about by microbes and also determined that bacteria were responsible for the spoilage of wine during fermentation. Pasteur in 1862 suggested that mild heating at 62.8°C (145°F) for 30 minutes rather than boiling was enough to destroy the undesirable organisms without ruining the taste of the product, the process was called Pasteurization. Pasteurization was introduced into the United States on a commercial basis in 1892. His work led to the development of the germ theory of disease. Louis Pasteur is known as the "Father of Modern Microbiology / Father of Bacteriology. John Tyndall(1820 - 1893): An English physicist, deal a final blow to spontaneous generation in 1877. He conducted experiments in an aseptically designed box to prove that dust indeed carried the germs. He demonstrated that if no dust was present, sterile broth remained free of microbial growth for indefinite John Tyndall period even if it was directly exposed to air. He discovered highly resistant bacterial structure, later known as endospore, in the infusion of hay. Prolonged boiling or intermittent heating was necessary to kill these spores, to make the infusion completely sterilized, a process known as Tyndallization. Around the same time that Pasteur was doing his experiments, a doctor named Robert Koch was working on finding the causes of some very nasty animal diseases (first anthrax, and then tuberculosis). He gave the first direct demonstration of the role of bacteria in causing disease. He was a German physician who first of all isolated anthrax bacillus (Bacillus anthracis, the cause of anthrax) in 1876. He perfected the technique of isolating bacteria in pure culture. He also introduced the use of solid culture media in 1881 by using gelatin as a solidifying agent. In 1882 he discovered Mycobacterium tuberculosis. He proposed Koch postulate which were published in 1884 and are the corner stone of the germ theory of diseases and are still in use today to prove the etiology (specific cause) of an infectious disease. Koch's four postulates are: 1. The organism causing the disease can be found in sick individuals but not in healthy ones. 2. The organism can be isolated and grown in pure culture. 3. The organism must cause the disease when it is introduced into a healthy animal. 4. The organism must be recovered from the infected animal and shown to be the same as the organism that was introduced. The combined efforts of many scientists and most importantly Louis Pasteur and Robert Koch established the Germ theory of disease. The idea that invisible microorganisms are the cause of disease is called germ theory. This was another of the important contributions of Pasteur to microbiology. It emerged not only from his experiments disproving spontaneous generation but also from his search for the infectious organism (typhoid) that caused the deaths of three of his daughters. Fanne Eilshemius Hesse (1850 - 1934) one of Koch's assistant first proposed the use of agar in culture media. Agar was superior to gelatin because of its higher melting (i.e. 96°c) and solidifying (ie. 40-45°C) points Fanne Ellshemius than gelatin and was not attacked by most bacteria. Hesse Koch's another assistant Richard Petri in 1887 developed the Petri dish (plate), a container used for solid culture media. Thus contribution of Robert Koch, Fannie Hesse and Richard Petri made possible the isolation of pure cultures of microorganisms and directly stimulated progress in allareas of microbiology. Richard Petri Petri dish (plate)  Developmentin Medicine and Surgery Once scientists knew that microbes caused disease, it was only a matter of time before medical practices improved dramaticaly. Surgery used to be as dangerous as not doing anything at all, but once aseptic (sterile) technique was introduced, recovery rates improved dramatically. Hand washing and quarantine of infected patients reduced the spread of disease and made hospitals into a place to get treatment instead of a place to die. Lord Joseph Lister (1827-1912): Afamous English surgeon is known for his notable contribution to the antiseptic treatment for the prevention and cure of wound infections. Lister concluded that wound infections too were due to microorganisms. In 1867, he developed a system of antiseptic surgery designed to prevent microorganisms from entering wounds by the application of phenol on surgical dressings and at times it was sprayed over the surgical areas. He also devised a method to destroy microorganisms in the operation theatre by spraying a fine mist of carbolic acid into the air, thus producing an antiseptic environment. AGPAT Thus Joseph Lister was the first to introduce aseptic techniques for control of microbes by the use of physical and chemical agents which are still in use today. Because of this notable contribution, Joseph Lister is known as the Father of Antiseptic surgery. Development of Vaccines Vaccination was discovered before germ theory,but it wasn't fully understood until the time of Pasteur. In the late 18th century, milkmaids who contracted the nonlethal cowpox sickness from the cows they were milking were spared in deadly smallpox outbreaks that ravaged England periodically. The physician Edward Jenner used pus from cowpox scabs to vaccinate people against smallpox. Edward Jenner (1749-1823) an English physician was the first to prevent small pox. He was impressed by the observation that countryside milk maid who contacted cowpox (Cowpox is a milder disease caused by a virus closely related to small pox) while milking were subsequently immune to small pox. On May 14th , 1796 he proved that inoculating people with pus from cowpoxlesions provided protection against small pox. Jenner in 1798, published his results on 23 successful vaccinators. Eventually this process was known as vaccination, based on the latin word Vacca' meaning cow. Thus the use of cow pox virus to protect small pox disease in humans became popular replacing the risky technique of immunizing with actual small pox material. Jenner's experimental significance was realized by Pasteur who next applied this principle to the prevention of anthrax and it worked. He called the attenuated cultures vaccines (Vacca = cow) and the process as vaccination. Encouraged by the successful prevention of anthrax by vaccination, Pasteur marched ahead towards the service of humanity by making a vaccine for hydrophobia or rabies. As with Jenner's vaccination for small pox, principle of the preventive treatment of rabies also worked fully which laid the foundation of modern immunization programme against many dreaded diseases like diphtheria, tetanus, pertussis, polio and measles etc.  Elie Metchnikoff (1845-1916) proposed the phagocytic theory of immunity in 1883. He discovered that some blood leukocytes, white blood cells protect against disease by engulfing disease causing bacteria. These cells were called phagocytes and the process phagocytosis. Thus human blood cells also confer immunity, referred to as cellular immunity. Elie Metchnikoff º Development of Chemotherapeutics, Antitoxins and Antibiotics Emile Roux (1853-1933) and Alexandre Yersin, the two notable French bacteriologists demonstrated the production of toxin in filtrates of broth cultures of the diphtheria organism. Emil von Behring (1854 -1917) and shibasaburo Kitasato (1852-1931) both colleagues of Robert Koch, in 1890 discovered tetanus (lock jaw) antitoxin. Only about a week after the announcement of the discovery of tetanus antitoxin, Von Behring in 1890 reported on immunization against diphtheria by diphtheria antitoxin. The discovery of toxin-antitoxin relationship was very important to the development of science of immunology. Paul Ehrlich (1854-1915) in 1904 found that the dye Trypan Red was active against the trypanosome that causes African sleeping sickness and could be used therapeutically. This dye with antimicrobial activity was referred to as a 'magic bullet!. Paul Ebrlich Subsequently in 1910, Ehrlich in collaboration with Sakachiro Hata, a Japanese physician, introduced the drug Salvarsan (arsenobenzol) as a treatment for syphilis caused by Treponema pallidum. Ehrlich's work had laid important foundations for many of the developments to come and the use of Salvarsen marked the beginning of the eni of chemotherapy and the use of chemicals that selectively inhibit or killpathogens without causing damage to the patient. Gerhard Domagk of Germany in 1935 experimented with numerous synthetic dyes and reported that Prontosil, a red dye used for staining leather, was active against pathogenic, Streptococci and Staphylococci in mice even though it had no effect against that same infectious agent ina test tube. In the same year two French scientists Jacques and Therese Trefonel showed that the compound Prontosilwas broken down within the body of the animal to sulfanilamide (Sulfa drug) the true active factor. Domagk was awarded Nobel prize in 1939 for the discovery of the first sulpha drug. The credit for the discovery of this first wonder drug' penicillin in 1929 goes to Sir Alexander Fleming of England, a Scottish physician and bacteriologist. Fleming had been actually interested in searching something that would kill pathogens ever since working on wound infections during the first worldwar (1914 1918). Alexander Fleming Antibiotics were discovered completely by accident in the 1920s, when a solid culture in a Petridish of bacteria was left to sit around longer than usual. As will happen with any food source left sitting around, it became moldy, growing a patch of fuzzy fungus. The colonies in the area around the fungal colony were smaller in size and seenned to be growing poorly compared to the bacteria on the rest of the plate.  The compound found to be responsible for this antibacterial action was named penicillin. The first antibiotic, penicillin was later used to treat people suffering from a variety of bacterial infections and to prevent bacterial infection in burn victims, among many other applications. In this way, Sir Alexander Fleming in 1929 discovered the first antibiotic penicillin. Waksman at the Rutgers university, USA discovered another antibiotie, streptomycin produced by two strains of actinomycete, Streptomyces griseus in 1944. Waksman received the noble prize in 1952 for his discovery of Streptomycin used in the treatment of tuberculosis, a bacterial disease caused by Mycobacterium tuberculosis that had been discovered by Robert Koch in 1882. By 1950, three other microorganism were identified that produced antibiotics, such as chloramphenicol (Chloromycetin) from Streptomyces venezuelae by Dr. Paul R. Burkholder in 1947, Aureomycin from S. aureofaciens by Dr. B.M. Dugger in 1948; and Terramycin from S. rimosus by Finlay, Hobby and collaborators in 1950. A dramatic turn in microbiology research was signaled by the death of Robert Koch in 1910 and advent of World war I. The Pasteur Institute was closed, and the German laboratories converted for production of blood components used to treat war infections. Thus came to an end what many have called the Golden Age of Microbiology. In 20th Century: Eraof Molecular Biology By the end of 1900, science of microbiology grew up to the adolescence stage and had come to its own as a branch of the more inclusive field of biology.  In the later years the microorganism were picked up as ideal tools to study various life processes and thus an independent discipline of microbiology, molecular biology was born. The relative simplicity of the microorganism, their short life span and the genetic homogeneity provided an authentic simulated model to understand the physiological, biochemical and genetical intricacies of the living organisms. The field of molecular biology made great strides in understanding the genetic code, how DNA is UE regulated, and how RNA is translated into proteins. Until this point, research was focused mainly on plant and animal cells, which are much more complex than bacterial cells. When researchers switched to studying these processes in bacteria, many of the secrets of genes and enzymes started to reveal themselves. * Historical Development in the Fieldof Microbiology 1220- Rogen Bacon, disease produced by invisible living creatures. 1252 1546 Girolamo Fracastoro, disease was caused by minute 'seed' or 'germ's spread from person to person. 1658 Athanasius Kircher, 1st recognize the significance of bacteria and other microbes in disease. 1665 Robert Hooke, referred as 'cells'. 1668 Franceso Redi, demonstrate the fallacies in the spontaneous generation theory. 1676 Antony Van Leeuwenhoek discovers Ianimalcules'. 1688 Redi Publishes work on spontaneous generation of maggaot. 1776 Lazzaro Spallanzani conducts experiment that dispute spontaneous generation. 1786 Muller produces first classification of bacteria. 1798 Edward Jenner introduces Cowpox vaccination for small pox. 1799 Spallanzani attacks on the theory of spontaneous generation. 1839 Theodor Schwann (german zoologist) and Mathias Schleiden (botanist) formulate the cell theory. 1857 Pasteur shows that lactic acid fermentation is due to a micro organism. 1858 Rudolf Virchow, (all celloriginate from pre existing cells). 1861 Pasteur shows that microorganism do not arise by spontaneous generation. 1867 Lister publishes his work on antiseptic surgery. 1869 Johann Meischer discovers nucleic acids. 1876- Koch demonstrate that anthrax is caused by Bacillus allthracis. 77 1881 Koch cultures bacteria on gelatin. 1882 Koch discovers tubercle bacillus. 1884 Koch's postulates first published. A Metchnikoff describes phagocytosis. A Autoclave developed. > Gram stain developed. 1885 Pasteur develops rabies vaccine 1887 Petridish developed by Richard Petri. 1892 D. Ivanovski provides evidence for virus causation ofT.M.V. 1897 Ross shows that malaria parasite is carried by the mosquito. 1899 Beijerinck proves that a virus particle causes the T.M.V. 1906 August Wasserman develops the first serologic test. for syphilis. 1908 Paul Ehrlich becomes the pioneer of modern chemotherapy to treat syphilis. 1910 Frances Rous discovers viruses that can induce cancer: 1915- F.D. Herelle and F. Twort independently discover bacterialviruses. 17 1923 First edition of Bergey's manual. 1928 Griffith discovers bacterial transformation. 1929 Alexander Fleming discovers penicillin 1935 Stanley crystallizes the T.M.V. 1944 Avery shows that DNA carries information during transformation. Selman Waksman discovers streptomycin. 1946 Lederberg and Tatum describe bacterial conjugation. 1952 Hershey and Chase show that bacteriophage inject DNA into host cells. Zinder &Lederberg discover generalized transduction. 1953 Watson & Crick propose the double helix structure for DNA. 1954 Jonas Salk develops the first polio vaccine. 1957 Isaacs and Lindenmann discover the natural antiviral substance, Interferon. 1958 Lederberg makes discoveries concerning genetic recombination and the organization of the genetic material of bacteria. 1959 Korenberg & Ochoa awarded Nobel prize for the discovery of enzyme which produces artificial DNA and RNA. 1966 Rousdiscovered tumor inducing viruses. 1971 T.0. Diemer identifies viroids. 1975 Kohler &Milstein develop technique for the production of monoclonal antibodies. 1977 Recognition of archaeobacteria as distinct microbial group. 1979 Henle identified first virus regularly associated with human cancer and insulin synthesized using rDNA techniques. 1982 Recombinant Hepatitis Bvaccine developed. 1982 Cech and Altman discovered catalytic RNA. 83 1983 Gallo and Montagnier isolated and identified HIV virus and PCR 84 chain reaction developed by Mullis. 1990 First human gene therapy testing begun. 1995 Lewis, Nusslein and Wieschans for the study of physiology of genetics of microbes. 1997 Prussiner discovery of prions. OSCOPE OF MICROBIOLOGY Microbiologists are currently in high demand across a variety of industries and fields all over the world. They are not restricted to only one of them, here are the most sought-after fields and areas in which the importance of microbiology is evidently large: Food Microbiology Environmental Science Biorefineries V Healthcare and Medicine / Hospitals V Genetic Engineering Universities / Biotechnology for Agro-chemistry Research Centres Boards for pollution control / Forensic Labs Food industry microorganisms are utilized in the preparation of different food products like cheese, pickles and alcohol, bread, vinegar and green olives. Environmental Science erah Fungal hyphae The field of microbiology the field is extensive. From understanding and applying microbes Bactera to understanding and using microbes and bioremediation, to the control of pests, microbiologists are able to tackle a variety of problems that are prevalent in this area. Vesces  Healthcare Sector Bacteria and other microbes are utilized to produce diverse Antibiotics and synthesize vitamins , which is vital to our bodies. They also are used in gene therapy to treat genetic disorders. This is the reason the field of microbiology in this area is growing. Genetic Engineering The field of microbiology within the field is huge due to the rising popularity of the discipline. The microbes' genes can be altered to make beneficial and valuable substanceslike hormones, enzymes and more. CAREERSIN MICROBIOLOGY With the growing awareness of the value of Microbiology numerous people are rushing to this field to study one of the lucrative courses that are available after the 12th science. These are the top jobs in Microbiology: > Biotechnologist In order to develop and develop items that are able to be utilized in numerous applications Biotechnologists conduct an extensive study of the chemical, physical and genetic properties of microbes. They also create easy-to-use products. From pharmaceutics and agriculture to food science and genetics the field of microbiology when working as STHe biotechnologist can be broad. Food Microbiologist When discussing the scope of microbiology food microbiologist is one profile that is highly sought-after. They work to reduce foodborne illness by conducting extensive studies on the microbes that cause disease and their environment, the packaging of food items, food poisoning, laws and regulations, etc.  Medicinal Chemist To identify ways to develop, design and optimize the effectiveness of drugs made from chemical compounds medical chemists play a important role in the field of pharmaceuticals. As a Medical Chemist is a broad field of microbiology does not just limit itself to the development of new formulations for drugs and also involves the creation of new methods by which drugs are made. If you are looking to pursue the foundation for a Career in Biochemistry it could be the ideal job. Pharmacologist As we have discussed, the application of microbiology isn't limited to a few particular fields, but can be utilized lo o across other industries as well. A pharmacologist is a career where microbiologists are highly sought-after. Finding and studying the connections between living and non-living substances in order to create new medicines is the major task of these experts. Nanotechnologist There are applications for nanotechnology in nearly every field, nanotechnology courses comprise elements of biology, chemistry, physics and pharmacology, microbiology etc. Technical Brewer In the industry of beer production technical brewers are the highest-ranking professionals who, with their technical and managerial skills supervise, control and manage the equipment and process of brewing. These experts must be proficient in terms related to microbiology. biochemistry, and so on.  Marine Biologist Marine biologists are a person who is interested in marine life and can identify the factors that disrupt the same. With a variety of microorganisms, such as algae, fungi, and bacteria being an integral element of marine life biologists study the physiological and behavioral functions for various species of the marine. They may also study taxonomy and fossil microbiology. Clinical Scientist Employed in clinics, hospitals as well as laboratories as well as research institutions, scientists try to make use of their expertise in the fields of medicine and biomedical research. They aid in the development of living organisms and also develop new treatments and medicines for it. For more information, check out our comprehensive guide on how to become Scientist! º Biomedical Scientist Typically working in the labs Biomedical scientists work with healthcare professionals like pharmacists or doctors to detect and treat various illnesses by analyzing different biopsies, fluids, and other types of samples. Forensic Scientist A DAY IN TE UFE OF A The field of microbiology can ORENSlc sclENTIS also be apparent when it comes Hane onme to Forensic Sciences. These experts utilize scientific and analytical expertise and techniques to analyze the evidence of crime scene and create legal statements for courts. They are usually involved in laboratory analysis or investigation of crime scenes.  OAPPLICATIONS OF MICROBIOLOGY Microbiology is among the most extensive and complex of biological sciences since it covers a variety of biological disciplines. Apart from investigating the microbiology of microbes it also examines every aspect of human-microbe and environmental interactions. These interactions encompass biology, genetics, metabolism and disease, as well as infection, immunology, chemotherapy as well as industry, genetic engineering and agriculture. > Medicine The ability to cause disease in certain microbes like. The Small Pox (Variola virus) Cholera (Vibrio cholera) Malaria (Plasmodium, protozoa) etc. They also provide us with the means to their control through antibiotics, as well as other medically significant medications. Biotechnology V Commercial applications comprise the production of acetone, organic acids, alcoh ols,enzymes, and a variety of other drugs. Genetic engineering is the process by which bacteria create important therapeutic substances like insulin and human growth hormone and interferon. Food Microorganisms have been utilized to make food items, starting with wine and brewing through cheese production, bread making, up to the manufacture Soy Sauce. Microbes also contribute to food spoilage.  Research Due to their simplicity, they are simpler to study biological processes in monocellular organisms, compared to multicellular organisms that are complex. Many copies of a single cell are produced in huge numbers, in a short time and at a low cost. This can provide lots of homogenous material for experiments. Since they reproduce extremely quickly, they can be useful in studies that involve transfers of information genetically. The environment Microbes play a role in the cycle of nitrogen, carbon and as well as phosphorus (geochemical cycles) Help to maintain the balance of nature on Earth They can be found in associations with plants insymbiotic relations that help to maintain soil fertility. They could also be used to ridthe earth of toxic substances (bio-remediation). > Future of Microbiology Future challenges will include coming up with new ways to fight diseases, cut pollution and feed the world's growing population. AIDS hemorrhagic fevers, hemorrhagic fevers, and other infections Develop new medicines, vaccines and vaccines. Utilize the methods of molecular biology or rDNA to address the issues Host-pathogen relationships Examine the role of microorganisms in the subject. Food sources of top quality as well as other useful products like enzymes for industrial applications Degrade toxic and harmful wastes and pollutants As vectors for treating ailments and increase the productivity of agricultural crops.  UNIT- I (CHAPTER- 2) PROKARYOTES & EUKARYOTES Points to be covered in this topic 1. PROKARYOTIC CELL ’2. CHARACTERISTICS OF PROKARYOTIC CELL 3. PROKARYOTIC CELL STRUCTURE 4. EUKARYOTICCELL 5. STRUCTURE OF EUKARYOTIC CELL 6. DIFFERENCE BETWEEN EUKARYOTIC CELL & PROKARYOTIC CELL DPROKARYOTIC CELL Prokaryotic cells are single-celled microorganisms known to be the earliest on earth. Prokaryotes include Bacteria and Archaea. The photosynthetic prokaryotes include cyanobacteria that perform photosynthesis. º Aprokaryotic cell consists of a single membrane and therefore, all the reactions occur within the cytoplasm. They can be free-living or parasites. Eukaryote Prokaryote s, agu A Characteristics of Prokaryotic Cell a. Prokaryotic cells have different characteristic features. The characteristics of theprokaryotic cells are mentioned below. b. They lack a nuclear membrane. c. Mitochondria, Golgi bodies, chloroplast, and lysosomes are absent. d. The genetic material is present on a single chromosome. e The histone proteins, the important constituents of eukaryotic chromosomes, are lacking in them. f. The cell wall is made up of carbohydrates and amino acids. g. The plasma membrane acts as the mitochondrial membrane carrying respiratory enzymes. h. They divide asexually by binary fission. The sexual mode of reproduction involves conjugation. 3 Prokaryotic Cell Structure Aprokaryotic cell does not have a nuclear membrane. However, the genetic material is present in a region in the cytoplasm known as the nucleoid. They may be spherical, rod-shaped, or spiral. A prokaryotic cell structure is as follows: º Capsule- It is an outer protective covering found in the bacterial cells, in addition to the cell wall. It helps in moisture retention, protects the cell when engulfed, and helps in the attachment of cells to nutrients and surfaces. Cell Wall-It is the outermostlayer of the cell which gives shape to the cell Cytoplasm-_The cytoplasm is mainly composed of enzymes, salts, cell organelles and is a gel-like component. Cell Membrane-This layer surrounds the cytoplasm and regulates the entry and exit of substances in the cells.  Pili- These are hair-like outgrowths that attach to the surface of other bacterial cells. Elagella-These are long structures in the form of a whip, that help in the locomotion ofa cell. Ribosomes- These are involved in protein synthesis. º Plasmids- Plasmidsare non-chromosomal DNA structures. These are not involved in reproduction. Nucleoid Region- _It is the region in the cytoplasm where the genetic material is present. Aprokaryotic cell lacks certain organelles like mitochondria, endoplasmic reticulum, and Golgi bodies. Prokaryotic Cell Diagram The prokaryotic cell diagram given below represents a bacterial cell. It depicts the absence of a true nucleus and the presence of a flagellum that differentiates it from a eukaryotic cell. Aibosomes cytoplasm Mesosome DNA Bacterial (Nucleoid) flagellum Cell wall Capsule Plasma membrane Components of Prokaryotic Cells The prokaryotic cells have four main components: Plasma Membrane- It is an outer protective covering of phospholipid molecules which separates the cell from the surrounding environment. Cytoplasm- It isa jelly-like substance present inside the cell. All the cell organelles are suspended in it. DNA- It is the genetic material of the cell. All the prokaryotes possess a circular DNA. It directs what proteins the cell creates. It also regulates the actions of the cell. > Ribosomes- Protein synthesis occurs here. Some prokaryotic cells possess cilia and flagella which helps in locomotion. Reproduction in Prokaryotes A prokaryote reproduces in two ways: > Asexualy by binary fission > Sexually by conjugation > Binary Fission 1. The DNA of an organism replicates and the new copies attach to the cell membrane. 2. The cell wall starts increasing in size and starts moving inwards. 3. Acell wall is then formed between each DNA, dividing the cell into two daughter cells. Chromosome Cytoplasm DNA Cytokinesis Replication identical Daughter cells > Recombination In this process, genes from one bacteria are transferred to the genome of other bacteria. It takes place in three ways- conjugation, transformation, transduction. Coniugation_is the process in which genes are transferred between two bacteria through a protein tube structure called a pilus. Transformation is the mode of sexual reproduction in which the DNA from the surroundings is taken by the bacterial cell and incorporated in its DNA. Transduction is the process in which the genetic material is transferred into the bacterial cell with the help of viruses. Bacteriophages are the virus that initiates the process. V Examples of Prokaryotic Cells The examples of the prokaryotic cells are mentioned below: * Bacterial Cells These are unicellular organisms found everywhere on earth from soil to the human body. > They have different shapes and structures. The cell wall is composed of peptidoglycan that provides stru cture to the cell wall. Bacteria have some unique structures such as pili, flagella and capsule. They also possess extra chromosomal DNA known as plasmids. They have the ability to form tough, dormant structures known as endospores that helps them to Cytoplasm survive under unfavorable cell membrane conditions. Murein cell wall Cell capsule The endospores become active the conditions are Nucleoid when Plasmid favourable again. Flagellum  Archacal Cells Archaebacteria are unicellular organisms similar to bacteria in shape and size. They are found in extreme environments such as hot springs and other places such as soil, marshes, and even inside humans. They have a cell wall and flagella. The cell wall of archaea does not contain peptidoglycan. The membranes of the archaea have different lipids with a completely different stereochemistry. Just like bacteria, archaea have one circular chromosome. They also possess plasmids. DEUKARYOTIC CELL º Eukaryotic cells have a nucleus enclosed within the nuclear membrane and form large and complex organisms. Protozoa, fungi, plants, and animals all have eukaryotic cells. They are classified under the kingdom Eukaryota. They can maintain different environments in a single cell that allows them to carry out various metabolic reactions. This helps them grow many times larger than the prokaryotic cells. º Characteristics of Eukaryotic Cells The features of eukaryotic cells are as follows: 1. Eukaryotic cells have the nucleus enclosed within the nuclear membrane. 2. The cell has mitochondria. 3. Flagella and cilia are the locomotory organs in a eukaryotic cell. 4.A cell wall is the outermost layer of the eukaryotic cells. 5. The cells divide bya process called mitosis. 6. The eukaryotic cells contain a cytoskeletal structure. 7. The nucleus contains a single, linear DNA, which carries all the genetic information.  OSTRUCTURE OF EUKARYOTIC CELL The eukaryotic cell structure comprises the following: Plasma Membrane The plasma membrane separates the cell from the outside environment. It comprises specific embedded proteins, which help in the exchange of substances in and out of the cell. Cell Wall A cell wall is a rigid structure present outside the plant cell. It is, however, absent in animal cells. It provides shape to the cell and helps in cell-to-cell interaction. It is a protective layer that protects the cell from any injury or pathogen attacks. It is composed of cellulose, hemicellulose, pectins, proteins, etc. Cytoskeleton The cytoskeleton is present inside the cytoplasm, which consists of microfilaments, microtubules, and fibres to provide perfect shape to the cell, anchor the organelles, and stimulate the cell movement. Endoplasmic Reticulum Endoplasnk rettculu It is a network of small, tubular structures Nucleolu Nucleus that divides the cell surface into two parts: Nucear pone luminal and extra luminal. Endoplasmic Reticulum is of two types:. Rough Endoplasmic Reticulum contains ribosomes. Smooth Endoplasmic Reticulum that lacks ribosomes and is therefore smooth.  Nucleolus > Nucleus Nudear envelope The nucleoplasm enclosed within the nucleus Nudear Pore contains DNA and proteins. The nuclear envelop consists of two layers the outer membrane and the inner Nucdeogtasm membrane. Both the membranes are permeable to ions, molecules, and RNA material. Ribosome production also takes place inside the nucleus. GolgiApparatus It is made up of flat disc-shaped olg açperatua cs face incomng transport vece structures called cisternae. cisternae umen It is absent in red blood cells of humans and sieve cells of plants. They are arranged parallel and concentrically near the nucleus. It is an important site for the formation of glycoproteins and glycolipids. trans face newty Sorming vescle secrtory Ribosomes These are the main site for protein synthesis and are composed of proteins and ribonucleic acids. º Mitochondria These are also known as "powerhouse of cells" because they produce energy. It consists of an outer membrane and an inner membrane. The inner membrane is divided into folds called cristae. They help in the regulation of cell metabolism. Lysosomes They are known as "suicidal bags" because they possess hydrolytic enzymes to digest protein, lipids, carbohydrates, and nucleic acids. º Plastids These are double-membraned structures and are found only in plant cells. These are of three types: Chloroplast that contains chlorophyll and is involved in photosynthesis. Chromoplast that contains a pigment called carotene that provides the plants yellow, red, or orange colours. Leucoplasts that are colourless and store oil, fats, carbohydrates, or proteins. EUKARYOTIC CELL DIAGRAM Eukaryotic cell diagram mentioned below depicts different cell organelles present in eukaryotic cells. The nucleus, endoplasmic reticulum, cytoplasm, mitochondria, ribosomes, lysosomes are clearly mentioned in the diagram. Cell Nucleus Membrane Rough Endoplasmic Mitochondrion Reticulum -Ribosome Smooth Endoplasmic Reticulum Cytoplasm Lysosome Golgi Centriole Apparatus M * Eukaryotic Cell Cycle (mitosis) G2 G1 The eukaryotic cells divide during the cell (Gap 2) (Gap 1) cycle. The cell passes through different EUKARYoTIC CELL CYCLE stages during the cycle. There are various Cells that checkpoints between each stage. S phase cease division (DNA synthesis)  Quiescence (G0) This is known as the resting phase, and the cell does not divide during this stage. The cell cycle starts at this stage. The cells of the liver, kidney, neurons, and stomach all reach this stage and can remain there for longer periods. Many cells do not enter this stage and divide indefinitely throughout their lives. º Interphase In this stage, the cells grow and take in nutrients to prepare them for the division. It consists of three checkpoints: Gap 1 (G1) - Here the cell enlarges. The proteins also increase. Synthesis (S) - DNA replication takes place in this phase. Gap 2 (G2) - The cells enlarge further to undergo mitotic division. º Mitosis Mitosis involves the following stages: Prophase V Prometaphase / Metaphase / Anaphase Telophase Cytokinesis º On division, each daughter cell is an exact replica of the original cell. Examples of Eukaryotic Cells Eukaryotic cells are exclusively found in plants, animals, fungi, protozoa, and other complex organisms. The examples of eukaryotic cells are Cell mentioned below: Cel enrane ROsome Golgs vesces Plant Cells Mucieohs Mcle The cell wall is made up of cellulose, which Rough ER provides support to the plant. It has a large wge Ceta Vaoole vacuole which maintains the turgor pressure. The plant cell contains chloroplast, which aids in the process of photosynthesis.  > Fungal Cells The cell wall is made of chitin. Some fungi have holes known as septa which allow the organelles and cytoplasm to pass through them. Animal Cells These do not have cell walls. Instead, they have a cell membrane. That is why animals have varied shapes. They have the ability to perform phagocytosis and pinocytosis. Mhaneren º Proto0z0a Protozoans are unicellular organisms. Some protozoa have cilia for locomotion. A thin layer called pellicle provides supports to the cell. DIEFERENCE BETWEEN PROKARYOTIC AND EUKARYOTIC CELLS Though these two classes of cells are quite different, they do possess some common characteristics. For instance, both possess cell membranes and ribosomes, but the similarities end there. The complete list of differences between prokaryotic and eukaryotic cells is summarized as follows: Prokaryotic Cell The term "prokaryote" is derived from the Greek word "pro", (meaning: before) and "karyon'" (meaning: kernel). It translates to "before nuclei." Prokaryotes are one of the most ancient groups of living organisms on earth, with fossil records dating back to almost 3.5 billion years ago. These prokaryotes thrived in the earth's ancient environment, some using up chemical energy and others using the sun's energy. These extremophiles thrived for millions of years,evolving and adapting. Scientists speculate that these organisms gave rise to the eukaryotes. Prokaryotic cells are comparatively smaller and much simpler than eukaryotic cells. The other defining characteristic of prokaryotic cells is that it does not possess membrane-bound cell organelles such as a nucleus. Reproduction happens through the process of binary fission.  Eukaryotic Cell The term "Eukaryotes" is derived from the Greek word "eu", (meaning: good) and "karyon" (meaning: kernel), therefore, translating to "good or true nuclei" Eukaryotes are more complex and much larger than prokaryotes. They include almost all the major kingdoms except kingdom monera. Structurally, eukaryotes possess a cell wall, which supports and protects the plasma membrane. The cellis surrounded by the plasma membrane and it controls the entry and exit of certain substances. The nucleus contains DNA, which is responsible for storing all genetic information. The nucleus is surrounded by the nuclear membrane. Within the nucleus exists the nucleolus, and it plays a crucial role in synthesizing proteins. Eukaryotic cells also contain mitochondria, which are responsible for the creation of energy, which is then utilized by the cell. PROKARYOTES EUKARYOTES Type of Cell Always unicellular Unicellular and multi cellular Cell size Ranges in size from 0.2 |Size rangesfrom 10 um um -2.0 um in diameter 100 um in diameter Cell wall Usually present; When present, chemically chemically complex in simple in nature nature Nucleus |Absent. Instead, they have Present a nucleoid region in the cell Ribosomes Present. Smaller in size Present. Comparatively and spherieal in shape |larger in size and linear in shape DNA arrangement Circular Linear Mitochondria Absent Present Cytoplasm Present, but cell Present, cell organelles organelles absent present Endoplasmic Absent |Present reticulum Plasmids Present Very rarely found in eukaryotes Ribosome Small ribosomes Large ribosomes Lysosome Lysosomes and Lysosomes and centrosomes are absent centrosomes are present Cell division Through binary fission Through mitosis Flagella The flagella are smaller inThe flagella are larger in size size Reproduction Asexual Both asexual and sexual Example Bacteria and Archaea Plant and Animal cell  UNIT-I (CHAPTER- 3) CULTURE MEDIA Points to be covered in this topic 1. INTRODUCTION 2. COMMON INGREDIENTS OF CULTURE MEDIA 3. TYPES OF CULTURE MEDIA BASED ON CONSISTENCY/ PHYSICAL STATE 4. TYPES OF CULTURE MEDIA BASED ON OXYGEN REQUIREMENT 5. TYPES OF CULTURE MEDIA BASED ON CHEMICAL COMPOSITION/APPLICATION 6.TYPES OF SPECIAL PURPOSE CULTURE MEDIA ’7. ROLE OFFERMENTATION MEDIA 8. APPLICATION OF CULTURE MEDIA O INTRODUCTION Culture media are mediums that provide essential nutrients and minerals to support the growth of microorganisms in the laboratory. Microorganisms have varying nature, characteristics, habitat, and even nutritional requirements, thus it is impossible to culture them with one type of culture media. However, there are also microorganisms that can't grow on a culture media at all in any condition - these are called obligate parasites. Common ingredients of culture media. Peptone- Source of carbon and nitrogen. Beefextract- Source of amino acid, vitamins, minerals. Yeast extract- Source of vitamin, carbon, nitrogen. Distilled water Agar- Solidifying agent. What is a Defined medium? A defined medium has a known quantity of all ingredients, like carbon source (Glucose or Glycerol) and nitrogen source (Ammonium salt or Nitrate as inorganic nitrogen). The medium needs in metabolic, nutritional, and physiological growth experiments. (Czapek Dox Medium) º Whatis an Undefined medium? This medium has different complex ingredients in unknown quantities, for example- yeast extract, beef, various salts, and enzymatic protein. (Potato dextrose agar, MacConkey agar) º What is Complex media? This media is other than basal media; it has added ingredients to bring the characteristics of microorganisms with unique nutrients.  Types of culture media based on consistency/ physical state 1. Solid medium 2. Semi-solid medium 3. Liquid medium 1. Solid media > Principle of Solid Media It is for the isolation of bacteria as a pure culture on a solid medium. Robert Koch realized the use of solid media. Agar is used to hardening the media at 1.5- 2.0% concentration. Solid media allows the growth of bacteria as colonies by streaking on the medium. It solidified at 37 degrees Celsius. Agar is an un-branched polysaccharide extracted from red algae species like Gelidium. Colonies identification is done on this medium. Examples of Solid Media Nutrient agar, MacConkey agar, Blood agar, Chocolate agar. / Growth of bacteria on solid medium appear as smooth, rough, mucoid, round, irregular, filamentous, punctiform. 2. Semi-solid media Principle of Semi-solid media This media shows the motility of bacteria and the cultivation of micro aerophilic bacteria. This media has agar at a concentration of 0.5% or less. It has a jelly consistency. Examples of Semi-solid media Stuart's and Amies media, Hugh and Leifson's oxidation fermentation medium and Mannitol motility media. The growth of bacteria in semi-solid appears as a thick line in the medium. 3.Liquidmedia > Principle of Liquid media This media shows the growth of a large number of bacteria. It is called Broth that allows bacteria to grow uniformly with turbidity. The growth occurs at 37°Cin an incubator for 24hrs. Liquid media don't have the addition of agar; it is for fermentation studies. Examples of Liquid media Nutrient broth, Tryptic soy broth, MR-VP broth, phenol red carbohydrate broth. Growth of bacteria in liquid media- Turbidity is seen at the end of the broth. * Types of culture media based on oxygen requirement Microorganisms have different requirements for growth depending on OxYgen requirements. 1. Aerobic media In this media, it is easy to cultivate microbes, on solid media, the growth occurs by keeping the culture in the incubator. It shows the growth;of non-fastidious microorganisms. Examples of aerobic media are-liquid media, solid media Peptone water- 1%peptone + 0.5% Nacl +100ml water. Nutrient agar- Nutrient broth +2% agar. 2. Anaerobic media " The media cultivates anaerobic bacteria at low oxygen, reducing oxidation-reduction potential. Anaerobic media contains extra nutrients like vitamin K, hemin and oxygen that get reduced by a physical or chemical process. The addition of glucose (1%), thioglycolate (0.19%), ascorbic acid (0.1%), cysteine (0.05%), or iron fllings added to cause the medium to reduce. The medium is boiled in a water bath to force out dissolved oxygen and packed with sterile paraffin. Examples of Anaerobic media RCM (Robertson cooked meat) isolation for Clostridíum sp. Thioglycolate broth- It has sodium glycolate that maintains low oxygen. Types ofculture media based on chemical composition/anplication There are seven routine laboratory media. 1. Basal media 2. Enriched media 3. Selective media 4. Enrichment media 5. Indicator media or differential media 6. Transport media 7. Storage media 1. Basal media This media is simple as it enhances the growth of many microorganisms. It's a routinely used medium in the lab, having Carbon and Nitrogen. This media allows the growth; of non - fastidious bacteria without any enrichment source; used for sub-culturing. It's a non-selective medium. Staphylococcus and Enterobacteriaceae grow in this media. Examples of Basal media NutrientAgar, Peptone water. 2. Enriched media This media requires the addition of other substances like blood, egg, or serum. An enriched media allows the growth of devised microorganisms but inhibits other and fastidious microbes grow as they require nutrients like vitamins and growth-promoting substances. Example of Enriched media Blood agar, Chocolate agar, LSS, Monsur's taurocholate, Lowenstein Jensen media. Blood agar identifies hemolytic bacteria, chocolate media for N. gonorrhea. 3. Selective media As by name, we can tell, this media shows the growth of selective; microbes or desired microorganisms and inhibits the growth of unwanted microbes. The inhibition occurs by adding bile salts, antibiotics, dyes, PH adjustments. Media is agar-based; any media is possible to transform into selective by adding inhibitory agar. * Examples of Selective media S.N. Culture media Inhibiting substances Bacteria Thayer Martin Contains antibiotics; Used for Neisseria 1 vancomycin, Colistin, and gonorrhoeae Agar Nystatin 2 Mac-Conkey's Contains bile salts Used for Entero Agar bacteriaceae members Lowenstein Addition of malachite Used for M. tuberculosis 3 Jensen Medium green Mannitol Salt Contains 10% NaCl Used tO recover S.aureus 4 Agar 5 Crystal Violet Contains 0.0002% crystal Used for Streptococcus Blood Agar violet Pyogenes Thiosulfate Have elevated pH of Used for Isolating Vibrio citrate bile salts about 8.5-8.6 cholerae 6 sucrose (TCBS) agar Wilson and Addition of dye brilliant Used for recovering S. 7 Blair's Agar green typhi Potassium Contalns 0.04% Used recover 8 tellurite medium Potassiumtellurite C.diphtheriae 9 pseudosel Agar Contalns cetrlmide Used to recover (cetrimide agar) (antiseptic agent) Pseudomonas aeruginosa Salmonella Contalns bile salts, Used for the isolation of 10 brilllant green, and Salmonella, which causes Shigella Agar sodium citrate typhoid  4. Transport media The media transport specimens after collection to control the overgrowth of organisms. For the cultivation, this media act as temporary storage. It also maintains the viability of pathogens in the specimen and prevents them from drying. Examples of Transport media Stuart's transport medium (lacks carbon, nitrogen, growth factors). Cary Blair's transport media and VR are used to transport feces samples from cholera patients. Pikes medium helps to transport streptococci from throat patients. 5.Indicator or differential media This media shows visible changes due to the presence of an indicator. It differentiates bacteria based on colony color growing on the same plate; biochemical characteristics show organism's growth with chemical indicators like neutral red, phenol red, methylene blue. OExamples of Indicator or differential media º Mannitol salt agar (mannitol fermentation shows yellow color colonies): blood agar is used to differentiate between hemolytic and non hemolytic. º MacConkey agar produces pink colonies due to lactose utilization and, non-lactose shows pale color colonies. 6. Enrichment media > It isa liquid medium, which also permits the growth of desired bacteria at a low density. The media provides an environment and conditions as selective media and inhibits unwanted bacteria from growing. > It is for the isolation of the soil and fecal microorganisms. Examples of Enrichment media Selenite F-broth does the isolation of Salmonella Typhi from a fecal sample. Selenium allows the growth of desired organisms and, detection levels increase for intestinal flora.  7. Storage media > It maintains the longevity of bacterial culture. Examples are- cooked meat broth, NA egg saline. 3 Types of special purpose culture media 1Assay media The media assay vitamins, amino acids, and antibiotics. Example Antibiotic sensitivity test the media used is Muller-Hinton agar has 1.7% agar for better diffusion of antibiotics. It also contains starch, which absorbs toxins released by bacteria. In this media plate Zone of inhibition is seen around antibiotics. 2. Minimalmedia Principal of minimal media Minimal media is a defined medium with different compositions depending on microorganisms cultured. > It contains a carbon source like sugar/succinate and inorganic salts like magnesium, nitrogen, sulfur, phosphorus. Carbon is a source of energy: magnesium and ammonium salts are the sources of ions for metabolism stimulation. Phosphate is a buffering agent. The growth comparison of microbe culture and mutant forms- Minimal media and supplementary-minimal media- allow the differentiation of wild-type and mutant cells. Use- The selection of recombinants, for the growth of wild-type microorganisms. 3. Fermentation media > The media is for optimum micro organisms. Fermentation media produce high yields of the product; media provide energy and nutrients for growth, and medium gives the substrate for the synthesis of products in the fermentation. Fermentation media contains major and minor components Major components - Carbon and nitrogen for energy. Minor components > This contains inorganic salts, growth factors, vitamins, buffer, anti foaming agents, dissolved oxygen, gases, growth inhibitors, enzymes. The nutrients in fermentation media depend on the organism and type of fermentation process. Growth media º It haslow nutrients and creates raw material for further fermentation. Fermentation media > It has high nutrients and creates end products. Example- The yeast requires 19% carbon, but the fermentation of alcohol, demands 12-13% carbon in the medium. * ROLE OF FERMENTATION MEDIA The media has a high level of nutrients, microorganisms, and optimum conditions. During the incubation period under optimum conditions, microorganisms undergo metabolism. Fermentation organisms become hyperactive due to nutrients being in high quantities and, the result is nutrients getting consumed, media partially degraded. The waste effluent is the output product. The death of cells occurs if substrate-level reaches the inhibitory concentration and excess substrate causes them to inhibit vital enzymes. Excess substrate increases osmotic pressure and disturbs enzymatic activity in cells. Microbes release excess substrate as partially digested fermentation media and convert it into the insoluble inert compound as reserve food, which is harmless to cells. Example- Yeast extract, Beef extract, YPD, BMGY. RESUSCITATION CULTURE MEDIA The resuscitation method is for the stressed bacterial recovery; this is a specialized medium that allows the growth of microbes that have lost the ability to produce because of the environmental harness. The culture provides nutrients and recovers their metabolism. For example- Bacteria require histamine for growth, and the medium lacks this component. Then it inhibits growth. The same bacterium is put in a medium having histamine, then it starts to grow again, and this medium acts as resuscitation media. For example- Tryptic Soy Agar. APPLICATION OF CULTURE MEDIA To culture microbes. To identify the cause of infection. To identify characteristics of microorganisms. To isolate pure culture. To store the culture stock. To observe biochemical reactions. To test microbial contamination in any sample. To check antimicrobial agents and preservatives effect. To observe microbe colony type, its color, shape, cause. To differentiate between different colonies. To create antigens for laboratory use. To estimate viable count. To test antibiotic sensitivity.  UNIT- I (CHAPTER- 4) BACTERIA Pointsto be covered inthis topic ’ 1. INTRODUCTION OF BACTERISA 2. ECOLOGY (HABITAT) OF BACTERIA 3. STRUCTURE OFABACTERIAL CELL External Structure of a Bacteria Internal structure of bacteria 4. SHAPES AND ARRANGEMENT OF BACTERIA 5. CLASSIFICATION OF BACTERIA / Classification of Bacteria based on Gram Staining / Classification of Bacteria based on Oxygen Requirements Classification of Bacteria based on optimum Temperature Classification of Bacteria based on Arrangement of Flagella Classification of Bacteria based on mode of nutrition  OINTRODUCTION Bacteria are microscopic, unicellular, prokaryotic organisms. They do not have membrane-bound cell organelles and lack a true nucleus, hence are grouped under the domain "Prokaryota" together with Archae. In a three-domain system, Bacteria is the largest domain. Bacteria, a singular bacterium, is derived from the Ancient Greek word "backerion" meaning "cane", as the first bacteria observed were bacilli. The study of Bacteria' is called 'Bacteriology', a branch of 'Microbiology. Evolutionof Bacteria Bacteria are considered as the first life-form to arise on the Earth about 4 billion years ago. All other life-forms are evolved from the bacteria. Ahyper-thermophile of about 2.5 - 3.2 billion years ago was the ancestor of bacteria and archaea that are found in the present time. Endosymbiotic association between diferent bacteria around 1.6 - 2.0 billion years ago give rise to the first proto-eukaryotic cell, which gradually gives rise to eukaryotes. Ecology (Habitat) of Bacteria Bacteria are evolved to adapt and survive in any kind of ecological niches; from normal to extreme environments. Hence, they are ubiquitous. They are found in every possible habitat on the Earth; soil, air, and water. They are associated with all the biotic and abiotic components of the Earth. They are essential components of every ecosystem. Such bacteria are called Extremophilic bacteria. They are found in extreme cold (Psychrophiles), extremely hot (Thermophiles), extreme pH (Acidophiles and Alkaliphiles), extreme pressure (Barophiles), anoxic environments (anaerobic), desertic area (Xerophiles), high radiation area, toxic wastes, barren sand and rocks, deep underground and mountain tip, etc.  Soil is the most heavily habituated place where they constitute about 0.5% W/W of the soil mass. One gram of topsoil may contain as many as one billion bacterial cells. It isestimated that there are approximately 2x100 bacteria on the Earth, but only around 2% of them are fully studied to date. " Hence, there is a huge research gap on the diversity and ecology of many unknown bacterial species. DSTRUCTURE OF ABACTERIAL CELL Capeue Bacteria are unicellular i.e. made up Raem of a single cell. They are prokaryotes den and their cells are different from Rosone Pasmi animal and plant cells. Elagen In general, the structure of bacteria can be studied as external and internal structures; External Structure of aBacteria It includes a cell wall and all the structures outside the cell wall. º 1. Flagella (sing. Flagellum) Flagella are long hair-like filamentous structures of about 4-5 um long and 0.01-0.03 um in diameter They confer motility to the bacteria. Flagella are divided into three parts; filament, hook, and the basal body. The filament is athreadlike part extending outside the cellwal. It is made up of Flagellin protein. The hook is a short curved structure that joins filament with the basal body. It produces repulsion like the propeller during the revolving of flagella. The basal body is a set of rings embedded in the cell wall and plasma membrane. It consists of 2 pairs of rings in Gram-Negative bacteria and 1 pair of rings in Gram-Positive bacteria. It synthesizes polymers of the flagellum, produces energy for revolution, and regulates movements of the flagellum. Functions of Flagella Responsible for motility Aids in Chemotaxis Aids in bacterial pathogenicity and survival 2. Pili/Fimbriae. They are the short, hollow, non-helical filamentous structure of about 0.5 um in length and 0.01 um in diameter. They are exclusively found in Gram-Negative bacteria. They are composed of protein 'pilin' arranged non-helically. They are short, numerous, and straight than flagella. Sex pili are a special kind of pilithat take part in bacterial conjugation. They are larger than usual pili; 10-20 um in length. They are few in number, just 1-4 in number. They are further classified into two types; F-pili and I pili. Functions of Pili/Fimbriae Aids in adherence to host cells Sex pili helps in bacterial DNA transfer during bacterial conjugation 3. Capsule It is a viscous outermost layer surrounding the cell wall. It is composed of either polysaccharides or polypeptides of both (~29%) and water (~98%). They are present only in some species of bacteria. The capsule is of 2 types; macro-capsule (capsule with a thickness of 0.2 um or more) and micro Streptococcus (Capsulated) capsule (capsule with thickness less than 0.2 um). Instead of viscous covering, some bacteria are surrounded by amorphous/ paracrystalline colloidal protein materials called the slime layer. Functions of Capsule Aids in adherence Prevents from desiccation Confer resistance against phagocytosis The Slime layer protects from proteolytic enzymes 4.Sheathand Prosthecae > Asheath is a hollow tube-like structure enclosing chain-forming bacteria, mostly aquatic bacteria. It provides mechanical strength to the chain. Prosthecae is a semi-rigid extension of the cell wall and plasma membrane. It increases nutrient absorption and also helps in adhesion. 5. Cell Wall " The cell wall is a rigid structure made up of peptidoglycan that surrounds the plasma membrane as an external coat. It is 10 -25 um in thickness. Peptidoglycan is a cross-linked polymer of alternately repeating N-Acetylmuramic Acid (NAM) and N-Acetyl glucosamine (NAG) polysaccharide sub-units. Gram-positive cell wall The gram-positive cell wall is a thick cell wall containing a large amount of peptidoglycan, about 40 - 90% of the cell wall, arranged in several layers. This type of cell wall also contains acidic sugars like Teichoic acids, teichuronic acids, and neutral sugars like mannose, arabinose, Rhamnose, and glucosamine as matrix substances. Teichoic acids are made of polyribitol phosphate or Sram-Postre Bacter CalWal Strsture polyglycerol phosphate. They Techoc Lpotectoc are major surface antigens of cid gram-positive bacteria. They are of two types; wall Teichoic acid Pgoga and lipoteichoic acid. Teichuronic acid is a polymer of N-acetylmannuronic acid or D Membrane pon glucuronic acid. This type of cell wall takes up the crystal violet dye and confer the purple color of the gram-positive bacteria in Gram staining.  Gram-negative cell wall The gram-negative cell wall is a thin cell wall with significantly less amount of peptidoglycan. " It is comparatively more complex than the gram-positive cell wall. It contains lipoprotein, lipopolysaccharide, and outer membrane in addition to peptidoglycan. The lipoprotein layer is composed of Braun's lipoprotein. It is embedded in the outer membrane and stabilizes the outer membrane. The outer membrane is a bilayered structure containing an inner layer -e9oooooooo MEMBRANE resembling the plasma membrane in ourER LIPOPROTEINS composition, and an outer layer PEPTIDOGLYCAN made up of lipopolysaccharide. 2ERIPUSMIC SPACE PRoTEN It is rich in a variety of proteins ASMIC GUgAANE like 'porin and outer membrane proteins. Lipopolysaccharide is a complex molecule consisting of 3 components; Lipid-A, core oligosaccharide, and 0-polysaccharide. Lipid-A is composed of phosphorylated glucosamine disaccharides, long chain fatty acids, and hydrosymyristic acid. Core oligosaccharide is composed of two sugars; keto-deoxy octanoic acid and a heptose sugar bounded together by Lipid A. O-polysaccharide are composed of a wide variety of sugars that difer in between bacterial strains. Cell-wall of acid-fast bacilli It is unique with a large number of mycolic acids. They resist the Decolorization of acid alcohol or sulfuric acid, hence called acid-fast. Bacteria withouta cell wall Mycoplasma is a minute (50 -300 nm) bacteria without a cellwall. They do not have a fixed shape. Besides this natural bacteria, there are several other cell walls deficient forms like protoplasts, spheroplasts, and L-forms.  * Gram-Positive Cell-Wall ys Gram-Negative Cell-Wall GRAM-POSITIVE CELL-WALL GRAM-NEGATIVE CELL-WALL Thick (20 - 80 nm) Thin (10 - 15 nm) Higher peptidoglycan content Lower peptidoglycan content Lower lipid content (2 - 5%) Higher lipidcontent (15- 20%) The main components are The main components are peptidoglycan, teichoic acid, and peptidoglycan, lipoprotein, teichuronic acid |lipopolysaccharide, outer membrane Very few amino acids without any Wide variety of amino acids with aromatic amino acids different aromatic amino acids * Internal structureof bacteria 1.Cell membrane/Plasma membrane > It is the innermost phospholipid bilayer, just beneath the cell wall, enclosing ytoplasm. It is athin (~5-10 nm) semipermeable layer. Unlike eukaryotie plasma membrane, they lack sterols (except in Mycoplasma), and comparatively have a higher proportion of proteins. In place of sterols, they have sterol-like compounds, called 'hapanoids. They contain a wide variety of fatty acids like usual saturated and unsaturated types and additionally methyl, hydroxyl, or cyclic groups too. The plasma membrane is equipped with several porin proteins for the passive transport of nutrients and ions. Functions of Cell membrane/Plasma membrane / Selective permeability regulates the inflow and outflow of nutrients, ions, and metabolites Electron transport and oxidative phosphorylation 2. Cytoplasm º It is a colorless, colloidal, viscous fluid with suspended organic and inorganic solutes enclosed within the plasma membrane. Unlike eukaryotic cytoplasm, they lack membrane-bound organelles. They have ribosomes, mesosomes, inclusion bodies, nucleic acids floating in them. 2.1 Ribosomes Bacterial ribosomes are of 7OS type and quite smaller than eukaryotic 80S types. They are made up of 2 subunits, the 50S, and 30S. Their main role is to synthesize bacterial proteins and enzymes. They are target sites for different antibiotics like erythromycin, macrolides, aminoglycosides, etc. 2.2 Mesosomes They are vesicular or branched structures formed by invaginated of the plasma membrane. They represent the eukaryotic mitochondria in function and are the site of action of the bacterial respiration enzymes. 2.3 Inclusion bodies > They are believed to be storage food. They are of two types; )Organic inclusion bodies, containing glycogen or polyhydroxy-butyrate granules, and () Inorganic inclusion bodies, containing polyphosphate or sulfur granules. 3. Bacterial Nucleus > They are called nucleoids. Unlike eukaryotic nuclei, they are not enclosed in the nuclear membrane and lack nucleolus and nucleoplasm. > It is represented by a dsDNA molecule either ina closed circular form or in coiled form. > Bacterial DNAs are found either in nucleoid as chromosomal DNA or outside nucleoid as a plasmid. 4. Endospore ofa bacteria Some bacteria under stress form a dormant stage called an endospore. They are produced during unfavorable environmental conditions. > They have four distinct structural components; ()Core, containing nucleoid and condensed cytoplasm, (i) Spore wall, the innermost wall of peptidoglycan, (ii) Cortex, the thickest wall with unusual peptidoglycan. (iv) Protein coat, an outer impermeable layer made of keratin like protein.  Shapes and Arrangement of Bacteria > Basically, bacteria are of four distinct shapes, cocci, bacilli, spiral, and comma-shaped. A. Coccishape bacteria They are spherical bacteria. Based on the arrangement of cells they are further sub-grouped as; i. Monococci; singular cocci. Eg. Micrococcus luteus, ii. Diplococci; two spherical bacteria are arranged in pairs. Eg. Neisseria spp., Moraxella catarrhalis, Streptococcus pneumoniae, etc. ii. Streptococci; spherical bacteria are arranged in a long chain. Eg. Streptococcus pyogenes, S. agalactiae, etc. iv. Staphylococci; spherical bacteria arranged in irregular clusters like a bunch of grapes. Eg. Staphylococcus aureus, S. saprophyticus, etc. V. Tetrad; arrangement in a group of 4 cocci. Eg. Aerococcus urinae, Pediococcus spp., etc. vi. Sarcinae; arrangement of cocci in a group of 8. Eg. Sarcina spp., Clostridium maximum,etc. Cocci Others Coccus Diplococci Diplococci (encapsulated) Staphylococci Club rod Vibrio Spirillum Helical form Sarcina Tetrad Streptococci cOccus cOCcus Spirochete Bacilli Filamentous Coccobacillus Bacillus Diplobacli Appendaged bacteria Streptobacillil Palisades Hypha Stalk  B. Bacillishape bacteria They are rod-shaped bacteria. Based on the arrangement of cells they are also sub-grouped as; 1.Bacillus /Mono-bacillus; single unattached rod-shaped bacteria. Eg. Salmonella enterica serovars, Bacillus cereus, etc. 2.Diplobacilli; bacilli arranged in a pair Eg. Moraxella bovis, Bacillus licheniformis, etc. 3.Streptobacilli; bacilli arranged in a chain. Eg. Streptobacillus moniliform, etc. 4.Palisade; bacilli arranged in fence-like form. Eg. Corynebacterium diptheriae, etc. 5.Coccobacilli; bacilli with rounded ends or oval-shaped. Eg. Chlamydia spp, H. influenzae, et. C. Spiral > They are long helical-shaped or twisted bacteria. Eg. Spirilla spp. , Spirochetes spp., etc. D. Comma shaped They are comma () like in structure. Eg. Vibrio spp. Besides these four basic shapes, several bacteria are found in other shapes like; 1. Filamentous (E.g. Actinobacteria, Candidatus savagella, etc.) 2. Star shaped (E.g, Stella vacuolata, Stella humosa, etc) 3.Appendaged / Budding (Eg Hypomicrobium, Rhodomicrobium, etc) 4. Pleomorphic (E.g. Mycoplasma spp.) 5.Chinese letter like (E.g. Corynebacterium spp.) 6. Lobed (Eg. Sulfolobus spp.) 7. Stalked (E.g. Caulobacter crescentus) 8. Sheathed (E.g. Leptothrix, Clonothrix)  Size of Bacteria Bacteria are microscopic with a wide range of sizes from 0.2 um to 100 m. Cocci are generally of 0.2 to 1.0 um. Bacilli are generally of 1.0 um 5 m in length and 0.5 to 1.0 um in diameter Spirochetes are generally 20 um in length and 0.1 to 1.0 um in diameter. The smallest bacilli are Pelagibacter ubique (370- 890 nm in length and 120- 200 nm in diameter). The smallest cocciare Mycoplasma genitalium with a diameter of 200 - 300 nm. The largest bacteria is Thiomargarita namibiensis with a diameter of 0.75 mm. Viruses Mycoplasma Bacteria Yeasts Eukaryotc cells Mycella 0.05-0.1 pm 0.1-0.5 um 1-10 ym 3-10 um 10-100 pm 100 um-several metres 0.05 pm 0.1 pm 0.5 um 1 pm 5 pm 10 um 50 pm 100 pm > 500 um Naked eye Lght microscopy Electron microecopy OCLASSIFICATION OF BACTERIA There are different schemes for the classification of bacteria. Some of the most common schemes of classifications are: a. Classification of Bacteria based on Gram Staining It is the most common mode of classification used widely in medical and research purposes. Bacteria are grouped into two groups as;  1. Gram-Positive Bacteria Bacteria having a thick peptidogycan layer and retaining the purple color of crystal violet during Gram staining are Gram-positive bacteria. E.g Staphylococcus Streptococcus, Enterococcus, Corynebacterium, Streptomyces, Bacillus, Haemophilus, Clostridium, Listeria, etc. 2.Gram-Negative Bacteria Bacteria having a thin peptidoglycan layer and losing crystal violet but retaining pink / red color of counterstain safranin during Gram staining are Gram-negative bacteria. E.g. Escherichia, Salmonella, Shigella, Neisseria, Klebsiella, Proteus Pseudomonas, Enterobacter, Citrobacter, etc. Gram-Positive Bacteria Gram-Negative Bacteria Stains violet/purple during Gram Stains red/pink during Gram staining staining Thin cell wall Thick cell wall V Thick peptidoglycan layer Thin peptidoglycan layer Lower mucopeptide and very high Higher mucopeptide and very low phospholipid phospholipid Mesosomes present Mesosomes absent (rarely present) Fimbriae or pili absent Fimbriae or pili present / Forms exospores Forms endospores Produce endotoxins Produce exotoxins V Teichoic acid absent, / Teichoic acid present, / Presence of an outer layer V Lack an outer layer b. Classification of Bacteria based on Oxygen Requirements Bacteria are classified into 3 types as; LAerobic bacteria They respire aerobically and can't survive in anoxic environments. E.g. Pseudomonas aeruginosa, Nocardia spp, Mycobacterium tuberculosis, etc. 2. Facultative aerobes They survive in very low oxygen levels and can survive in both oxygenic and anoxic environments. They are Microaerophiles. E.g. E. coli, Klebsiella pneumoniae, Lactobacillus spp., Staphylococcus spp., etc. 3.Anaerobic bacteria They respire anaerobically and can't survive in an oxygen-rich environment. E.g. Clostridium perfinges, Campylobacter, Listeria, Bifidobacterium, Bacteroides, etc. c.Classification of Bacteria based on Optimum Temperature Bacteria are classified broadly into 3 types as; 1. Psychrophiles They have optimum growth temperature at 15°C or below. E.g. Chryseobacterium, Psychrobaceter, Polaromonas, Sphingomonas, Alteromonas, Hyphomonas, Listeria monocytogenes, etc. 2. Mesophiles They have optimum growth temperature at 15 - 45°C. Pathogenic bacteria fall in this category. E.g E. coli, Staphylococcus aureus, Salmonella Typhi, Streptococcus pyogenes, Klebsiella spp, Pseudomonas spp, etc. 3.Thermophiles They have optimum growth temperature at above 45°C. E.g. Bacillus thermophilus, Methanothrix, Archaeglobus, Thermophilus aquaticus, Geogemma barosii (at 122°c), Pyrolobus fumarii (at 113°C), Pyrococcus spp., etc. d.Classification of Bacteria based on Arrangement of Flagella Bacteria are classified into 5 types as; 1. Atrichous They are bacteria without flagella. E.g, Lactobacillus spp., Bacillus anthracis, Staphylococcus spp., Streptococcus spp, etc.  2. Monotrichous They are bacteria with only one flagellum at one pole. E.g. Campylobacter spPp, Vibrio cholerae, etc. 3.Lophotrichus They are bacteria with multiple flagella at one end. E.g. Spirillum, Helicobacter pylori, Pseudomonas fluorescence, etc. 4. Peritrichous They are bacteria with multiple flagella projecting in all directions. E.g. E. coli, Klebsiella, Proteus, Salmonella Typhi, etc. 5. Amphitrichous They are bacteria with one flagellum at each pole. E.g. Alcaligenes faecalis, Nitrosomonas, etc. e. Classification of Bacteria based on mode of nutrition 1. Autotrophic bacteria They are bacteria capable of assimilating inorganic matters into organic matters i.e. capable of preparing their food like plants. They are of 2 types; Photoautotrophs; They use energy from sunlight for assimilation. It includes cyanobacteria (Nostoc, Prochlorococcus, etc.), purple sulfur bacteria (Nitrosococcus, Thiococcus, Halochromatium, etc.), purple non sulfur bacteria (Rhodopseudomonas spp.). green sulfur bacteria (Chlorobium, Chromatium, etc) Chemoautotrophs; They use chemical energy for assimilation. It includes sulfur bacteria (Beggiatoa, Thiobacillus, Thiothrix, Sulfolobus, etc.), nitrogen bacteria (Nitrosomonas, Nitrobacter, etc.), hydrogen oxidizing bacteria (H. pylori, Hydrogenbacter, Hydrogenvibrio marinus, etc.), methanotrophs (Methylomonas, Methylococcus, etc), iron bacteria (Thiobacillus ferroxidans, Ferrobacillus, Geobacter metallireducens, etc) 2.Heterotrophic bacteria They are bacteria that derive energy by consuming organic compounds, but they do not convert organic compounds to inorganics. They are parasitic or symbiotic types. E.g. E. coli, Rhizobium spp., Staphylococcus spp, Mycobacterium spp, Klebsiella pneumoniae, etc. 3. Saprophytic bacteria They are bacteria that decompose organic compounds into inoranic and derive energy. They are decomposers and feed on dead plants and animals. E.g. Cellulomonas, Clostridium thermosaccharolyticum, Pseudomonas denitrificans, Acetobacter, etc. FEEDING IN BACTERIA Bacteria feed on several organic or inorganic compounds. The food enters the bacterial body either by phagocytosis (active transport) or by osmosis and diffusion or through protein channels (passive transport). They obtain energy by either photo- or chemosynthesis decomposing organic compounds or breaking down inorganic compounds. Based on feeding habits, they are grouped as autotrophs, heterotrophs, and saprophytes.  UNIT-I (CHAPTER- 4.1) BACTERIA Points to be covered in this topic 1. REPRODUCTION IN BACTERIA 2. BACTERIAL METABOLISM 3. RESPIRATION IN BACTERIA 4.FERMENTATION IN BACTERIA 5. BACTERIAL DISEASES 6. BACTERIAL IDENTIFICATION Cultural Methods for Bacterial ldentification Staining and Microscopy for Bacterial Identification Biochemical Tests for Bacterialldentification d. Molecular Methods for Bacterial ldentification / e. Immunological Methods for Bacterial ldentification 7. IMPORTANCE, USES AND APPLICATIONS OF BACTERIA +8. DISADVANTAGES AND LIMITATIONS OF BACTERIA  OREPRODUCTION IN BACTERIA Bacteria have a very short generation time ie. they reproduce very quickBy The