Microbiology History and Key Concepts

• Microbiology includes the study of microscopic organisms like bacteria, fungi, protists, and viruses, covering aspects such as behavior, evolution, ecology, biochemistry, physiology, and pathology of diseases.

Branches of Microbiology

• Pure microbiology includes bacteriology (study of bacteria), mycology (study of fungi), protozoology (study of protozoa), phycology/algology (study of algae), parasitology (study of parasites), immunology (study of the immune system), virology (study of viruses), and nematology (study of multicellular nematodes).
• Applied microbiology/biotechnology includes medical, pharmaceutical, and industrial applications and genetic manipulation of microorganisms for useful products.

History of Microbiology

• The term "Microbiology" was coined by Louis Pasteur (1822-95), with the science expanding after 1850.
• "Microbe" was first used by Sedillot in 1878.

Transition Period

• Scientists once believed life sprang spontaneously from mud or lakes with sufficient nutrients.

Key Figures Challenging Spontaneous Generation

• Francesco Redi challenged spontaneous generation with experiments involving decaying meat.
• John Needham supported spontaneous generation, proposing tiny organisms arose in mutton gravy.
• Lazzaro Spallanzani refuted Needham by boiling beef broth and sealing flasks, but showed heated nutrients could grow animalcules when exposed to air.
• Nicolas Appert preserved soups and liquids by heating them in thick champagne bottles.
• Ignaz Semmelweis and John Snow heightened awareness of disease transmission, while Schulze and Theodor Schwan viewed air as a source of microbes.
• George Schroeder and Theodor Von Dusch introduced cotton plugs for microbial culture tubes.
• Darwin's ‘Origin of the Species' suggested disease may be a biological phenomenon, rather than magic.

Golden Age of Microbiology

• The era began with Louis Pasteur and Robert Koch, marking real beginnings of microbiology as biology discipline
• Louis Pasteur disproved spontaneous generation using goosenecked flasks, showing organisms grew in straight-necked flasks but not when dust particles were trapped in S-shape of goosenecked flasks.
• Pasteur found fermentation of fruits/grains was by microbes & bacteria caused wine spoilage.
• Pasteurization involves mild heating at 62.8°C (145°F) for 30 min to destroy undesirable organisms.
• Louis Pasteur is known as the "Father of Modern Microbiology / Father of Bacteriology".

Louis Pasteur's Contributions

• Proposed fermentation principles, introduced sterilization techniques, described pasteurization of milk.
• Contributed to vaccines against anthrax, fowl cholera, and rabies.
• Disproved spontaneous generation, stated disease is produced by microorganisms present in the air.
• Initiated liquid media concept and founded the Pasteur Institute, Paris.

Contributions to Germ Theory

• John Tyndall dealt final blow to spontaneous generation in 1877, demonstrating that dust carried germs and discovering endospores.
• Prolonged boiling or intermittent heating kills endospores, known as Tyndallisation.
• Robert Koch demonstrated bacteria's role in diseases, isolating Bacillus anthracis.
• Koch perfected isolating bacteria in pure culture and using solid culture media with gelatin, discovering Mycobacterium tuberculosis in 1882.
• Koch's postulates, published in 1884, are the foundation of germ theory.
• One requirement is the organism causing the disease MUST be recovered from the infected subject and displayed to be like the initial organism
• The combination of Pasteur and Koch resulted in the Germ theory of disease and the idea that microorganisms cause disease.
• Fanne Eilshemius Hesse proposed agar use in culture media, Richard Petri developed Petri dish.

Medical Practice Improvements

• Once scientists knew microbes caused disease, medical practices improved dramatically.
• Aseptic techniques, hand washing, and quarantine reduced disease spread.
• Lord Joseph Lister introduced antiseptic surgery using phenol to prevent microorganisms from entering wounds which marks aseptic techniques for microbe control.
• Joseph Lister is know as Father of antiseptic surgery
• Edward Jenner prevented smallpox using cowpox, leading to vaccination, "Vacca" meaning cow.
• Elie Metchnikoff proposed phagocytic theory of immunity.

Antibiotics and Chemotherapy

• Emile Roux and Alexandre Yersin demonstrated toxin production in diphtheria organism.
• Emil von Behring and Shibasaburo Kitasato discovered tetanus antitoxin.
• Paul Ehrlich found Trypan Red active against trypanosome, introduced Salvarsan for syphilis treatment.
• Paul Ehrlich work marked the use of chemotherapy to kill pathogens without harming the patient.

Contributions of Paul Erlich

• Paul was first to find acid-fast nature of tubercle bacillus, developed tissue/blood cell staining techniques
  • Reported toxin-antitoxin interaction and proposed antibody production theory.
  • Discovered salvarsan for syphilis treatment as magic bullet and hence "Father of chemotherapy".
  • The bacteria 'Ehrlichia'was named after him.

Discovery of Antibiotics

• Sir Alexander Fleming discovered penicillin in 1929, which kills pathogens.
• Waksman discovered streptomycin from Streptomyces griseus in 1944.

The End of The Golden Age of Microbiology

• Pasteur's scientific efforts were recognized after is death by the Nobel Prize awardees.
• Robert Koch's death in 1910 and World War I signaled the end of microbiology's golden age.

Era of Biology Introduction

• The field grew up in biology as microorganisms were picked up as ideal tools to study various life processes, thus molecular biology was born.
• Research shifted to bacteria, revealing secrets of genes and enzymes.
• Molecular Koch's postulates involve genes coding virulence.

Contributors in Microbiology

• Antonie Philips van Leeuwenhoek: Discovered single-lens microscope and named organisms as 'Little animalcules'.
• Edward Jenner: Developed the first vaccine of the world, the smallpox vaccine by using the cowpox virus.
• Joseph Lister: Joseph Lister is considered to be the father of antiseptic surgery. He used carbolic acid during surgery.
• Hans Christian Gram: He developed a 'Gram stain'.
• Ernst Ruska: He was the founder of the electron microscope.
• Alexander Fleming: He discovered the antibiotic penicillin.
• Elie Metchnikoff: He described phagocytosis and termed phagocytes.
• Kleinberger: He described the existence of L forms of bacteria.
• Barbara McClintock: She described transposons.
• Walter Gilbert and Frederick Sanger: were the first to develop (1977) the method of DNA sequencing.
• Karry B Mullis: Discovered polymerase chain reaction (PCR).
• Robert Hooke saw first cells.
• Anton van Leeuwenhoek observed called what he called "animalcules" with the use of his homemade microscopes.

Prokaryotes vs. Eukaryotes

• Prokaryotes are small cells lacking a nucleus and complex organelles, including Bacteria and Archaea.
• Eukaryotes are complex cells with a nucleus and organelles, including animals, fungi, and protoctista.
• Prokaryotes have a protective capsule, pili for attachment, and may contain mesosomes and plasmids.
• Eukaryotic cells possess a cell wall, plasma membrane, DNA-containing nucleus, and mitochondria.
• Prokaryotes reproduce through binary fission, eukaryotes through mitosis or meiosis.
• Prokaryotes have a single, circular DNA free in cytoplasm, and 70S ribosomes vs the more organized structure of eukaryotes
• Eukaryotes have many structures enveloped by single/double membranes
• Eukaryotes have cell wall of plants but bacteria has one containing polysaccharides-amino acids-murein
• Eukaryotes cell wall has strengthening elements such as cellulose -Most prokaryotes contain are Rigid while eukaryotes containt very few
• Plasmids very rare in eukaryotes but more popular in prokaryotes
• Endoplasmic reticulum - if this exists in prokayotes IT IS ALWAYS PRESENT. Eukaryotes - ABSENT

Cell Processes

• Eukaryotes make use of Mitochondria for aerobic respiration
• Prokaryotes make use of mesomes for respiration
• Lysosomes exist only in eukaryotes
• Flagella more large for Eukaryotes, simple in structure for prokaryotes

Classification of Prokaryotes

• The three main types of living categories are: Bacteria, Archaea, and Eukarya (also called Eukaryotes).
• horizontal gene transfer occurs when a cell acquires external DNA, resulting in shared DNA between unrelated individuals.
• • All prokaryotas have protective structures called cell walls- composition differes significantly between the three domains of life.
• cell wall for Bacterial is peptidoglycan versus polysaccharides for archaea; while eukaryotic wall has ells is cellulose and fungal is chitin.

Archa and Eubacteria- Cell well Composition

• Archae is pseudo peptidoglycans while Eubacteria is peptidoglycans with muramic acid.
• Growth for Arcae is asexual- binary fission or fragmentation and more, eubacteria has spores for hostile conditions
• growth for archae usually in extreme conditions and eubacteria are more often not

Disinfection vs Sterilization

• Sterilization kills all microorganisms via physical/chemical agents unlike disinfection which kills the same on inanimate objects
• Skin cannot be completely sterilized; disinfection in labs involves sterilization to implement culture media, reagents and equipment.

Sterilization Methods

• Dry heat kills spores. This method common with gladdwares, use heat sterilization causes Toxic effect
• Dry heat involves dry enviroinments, wet envolves moist
• Boil for 30 min with water or steam; but autoclave is MOST common method of steilization.

Moist Heat Sterilization

• Moist heat involves Tyndallization cycles for heat labile material; Autoclaving using hight pressure steam.
• Pasteurization reduces pathogens in liquids, does not sterilize and leads to protien denaturing
• Denaturing denaturizes the protien, causes loss of integrity, breaks DNA
• Filtration: used for media in general that cannot be added to heat
  • Used filter membranes
• UV Radiation: Used for laminar flows, sterile cabinets , but needs to be applied with autoclaving, hot air
• all the techniques use use

More cleaning Methods

• Disenfectent- Kills vegetation Cleaning- Removes contamination for safety

sanitization actions:

• Doesnt require sterilization cleaning, or antisepsis , cleaning the environment
• reduces microorganism for infection/spoilage

Degermination

• Lowers amount of microbes on skin by scrubber

MICROORGANISM ECONOMY

• Bacteria are both detrimental AND benificial.

Agricultire

• Bacteria Decay Organic Substance Causes decay of waste

Soil fertility

• Maintaines and increases fertilizes
• Changes materials to soluble forms
• The actions they undertake allow for ammonifying, Nitrifying and nitrogen Fixing processes.
• these bacterias take in nitrogen from the atmosphere- making nitrogen fixation

Industry

• creates alcohols and the products used in tea, wine , coffee. cheese fibers are also made during these processes.

Antibiotics

Are used for protection/treatment.

Good Harmful Actions For Bacterias

• bacteria has the ability to have various processes: animal/plant, food , soil destroying bacteria, and Animal disease
• Bacteria can affect domestic animalds, plants- citrus canker, or even humans.
• Bacteria reduces nitrates- results in a loss of plants. which means a loss of growth by plants The nitrogen cycle is ruined.

Importance bacteria

Bacteria are used for protection and can make antibiotics- they can also act adversly and be resistant.

Harm

Deteriorization of domestic articals

Fungi

• is a kingdom in mircooriganism group- cosmopolitan- yest and mold
• Used to create penicllin; also helps enchance soil, improve plant growth, product bread with most use with yeast and help in food Can both be good and bad Some viruses can casue diseases Virus Vaccine can help protect you.

Factors to have good microbial and aquatic growth

• Have low or high PH- high can destroy some microbes
• Have light available
• Good nutrients.

Explore the historical milestones in microbiology, including Koch’s postulates and the contributions of scientists like Joseph Lister and Paul Ehrlich. Understand the difference between prokaryotes and eukaryotes and the development of vaccines and antibiotics. Review key concepts in immunology.