Microbiology Chapter 1 PDF

Chapter 1 Microbiology Microbes In our Lives: Microorganisms are organisms that are TOO small to be seen with the unaided eye. Microbes include bacteria, fungi, protozoa, microscopic algae, and viruses. A few are pathogenic (disease-producing) ○ Pathogenic: viruses, a ba...

Chapter 1 Microbiology Microbes In our Lives: Microorganisms are organisms that are TOO small to be seen with the unaided eye. Microbes include bacteria, fungi, protozoa, microscopic algae, and viruses. A few are pathogenic (disease-producing) ○ Pathogenic: viruses, a bacterium that causes disease. Decompose organic waste ○ Bioremediation is the use of naturally occurring, introduced microorganisms or other forms of life to consume and break down environmental pollutants in order to clean up polluted sites. Generate oxygen by photosynthesis Produce chemical products such as ethanol, acetone, and vitamins. Produce fermented foods such as vinegar, cheese, and bread. Produce products used in manufacturing (e.g. cellulose) and disease treatment (e.g. insulin) ○ Insulin is produced in response to blood sugar levels. Knowledge of microorganisms allows humans to: ➔ Prevent food spoilage ➔ Prevent disease ➔ Understand the causes and transmission of disease to prevent epidemics. Naming and Classifying Microorganisms Carlos Linnaeus established the system of scientific nomenclature in 1735. Each organism has two names: the genus and the specific epithet. Nomenclature Scientific names  ○ Are italicized or underlined The genus is capitalized: the specific epithet is lowercase ○ Are “Latinized” and used worldwide ○ May be descriptive or honor a scientist Escherichia coli - Honors the discoverer, Theodor Escherich - Describes the bacterium’s habitat-the large intestine, or color - Definition: Digestion of a harmful bacteria entering your body. (E. coli) Staphylococcus aureus - Describes the clustered (staphylo-) spherical (coccus cells) - Describes the gold-colored (aureus) colonies. (describing the color) - Definition: can cause infection when it enters the body through a break in the skin or mucous membranes: After the first use, scientific names may be abbreviated with the first levels of the genus and the specific epithet. - Escherichia coli and Staphylococcus aureus are found in the human body. - E. coli is found in the large intestine, and S. aureus is on the skin. Types of Microorgnaims: Bacteria Archaea Fungi Protozoa Algae ○ Usually are photosynthetic (usually not pathogenic) Viruses (not living cellular) Multicellular Animal Parasites ○ Ex: Helminth (parasitic worms) Bacteria Prokaryotes ○ “Prenucleus” Single-celled  Peptidoglycan cell walls Divide via binary fission ○ This means that a bacterium produces by splitting itself into two identical daughter cells, creating a copy of itself through a process called binary fission. Asexual reproduction. Derive nutrition from organic or inorganic chemical or photosynthesis May “swim” by using moving appendages called flagella. Bacteria cell structure: Archaea Are prokaryotes Lack of peptidoglycan cell walls ○ May lack cell walls entirely Often live in extreme environments Include: ○ Methanogens ○ Extreme halophiles Live in extremely salty conditions ○ Extreme thermophiles Thrive in high-temperature environments Generally not known to cause disease in humans. Fungi Eukaryotes  ○ Distinct nucleus surrounding DNA genetic material Chitin cell walls Absorb organic chemicals for energy Yeasts are unicellular Molds and mushrooms are multicellular ○ Molds consist of mycelia masses, composed of filaments called hyphae. Images of a type of organism: Hyphae (a type of fungi) - Kills or inhibits growth - Do not give antibiotics because not caused by bacteria - If antibiotics are given, it creates resistance and does not protect against bacterial infection. Hyphae are long, branching filaments that make up the structure of fungi. They are the basic building blocks of fungi and are responsible for growth, nutrient absorption, and reproduction. Hyphae grow by extending at their tips and forming a network called a mycelium. Some Anitfungal treatments target hyphae to stop fungal browth. For example, certain antifungal drugs can damage cell walls of the fungus, which will inhibit the growth of hyphea. ○ Antibiotics won’t affect anything because antibiotics target bacteria, not fungi growth. ○ If given antiobiotics used incorrecntly to treat a fungal infection, they would NOT be effective and could contribute to antiobiotic resistance. Protozoa Eukaryotes ○ Are unicellular ○ Could be pathogens Absorb or ingest organic chemicals May be motile via pseudopods, cilia, or flagella ○ Protozoa can use different mechanisms - pseudopods, cilia, or flagella - to move through their environment, depending on the species. Free-living or parasitic (derive nutrients from a living host) ○ Some are photosynthetic Reproduce sexually or asexually. Algae Eukaryotes ○ Can be either multi or unicellular Cellulose cell walls Found in freshwater, saltwater, and soil Use photosynthesis for energy ○ Produces oxygen and carbohydrates Sexual and asexual reproduction is possible. Viruses Acellular Consist of DNA or RNA core The core is surrounded by a protein coat  ○ The coat may be enclosed in a lipid envelope (some may have envelope) Are replicated ONLY when they are in a living host cell. ○ Insert outside living hosts. **************GO OVER THIS PART → Multicellular Animal Parasites Eukaryotes Multicellular animals Not strictly microorganisms Parasitic flatworms and roundworms are called helminths ○ Some microscopic stages in their life cycle Classification of Microorganisms Developed by Carl Woese in 1978 ○ Domains are the broadest units of classification Three domains based on cellular organizations: ○ Bacteria ○ Archaea ○ Eukarya Protists Fungi Plants Animals The most SUCCESSFUL on Earth are prokaryotes. Three domain system: Description: Archaea and Bacteria came first during evolution, then Eukarya came into light. Bacteria is the origin of prokaryote by endosymbiotic. First Observations: 1665: Robert Hooke reported that living things are composed of little boxes, or “cells” ○ Marked the beginning of cell theory: All living things are composed of cells The first microbes were observed from 1623 to 1673 by Anton van Leeuwenhoek (Father of microbiology) (got credit to discover bacteria) ○ “Animalcules” viewed through magnifying lenses Description: the image of the tool used for Anton van Leeuwenhoek. First saw microorganisms (bacteria) by magnifying them 300 times more. Robert Hooke Built a compound microscope Observed thin slices of cork Continued the term “cells” (1665) Observed protozoa and some fungi This was the beginning of the cell theory. The Debate over Spontaneous Generation: ➔ Spontaneous generation: the hypothesis that life arises from nonliving matter; a “vital force” is necessary for life. ➔ Biogenesis: the hypothesis that living cells are ONLY from preexisting living cells. Summary: biogenesis is the idea that cells only grow in the existence of other living cells but spontaneous generation means that life can appear out of nowhere, even if it's covered from any living cell life. Examples of Spontaneous Generation examples: ★ 1745: John Needham put boiled nutrient borth into covered flasks. ○ Conditions: nutrient broth heated, then placed in covered flask → (results): microbial growth. Would be considered to be spontaneous (but the experiment is wrong). The flask is not sterile, so microorganisms are already present in the broth. Examples of Biogenesis examples: ★ 1668: Francesco Redi filled jars with decaying meat. ○ Conditions: Jars covered with fine net → No maggots  Opened jars → maggots appeared Sealed jars → no maggots ○ Purpose of the sealed jars? Prevents from flies arriving at the jar and laying their eggs. Considered to be biogenesis ★ 1765: Lazzaro Spallanzani boiled nutrient solutions in sealed flasks ○ Conditions: Nutrient broth placed in a flask, sealed, then heated → (results): no microbial growth. ○ Biogenesis The Theory of Biogenesis Cell theory was eventually formulated in 1839. Many scientists like Rudolf Virchow contributed to the theory. 1858: Rudolf Virchow said cells arise from preexisting cells - biogenesis. ○ It was an important step in the movement away from spontaneous generation. The Cell Theory All living things are composed of cells. The cell is the basic unit of structure and organization in organisms. Cells arise from pre-existing cells. The Theory of Biogenesis Pasteur also used S-shaped flasks ○ Keep microbes out but let air in The broth in flasks showed NO signs of life The neck of the flask traps microbes Microorganisms originate in air or fluids, not mystical forces. The invention that was used to disprove the spontaneous generation by adding broth into the long-necked flask and heating up, seeing that no microbes were present, meaning that there are only microorganisms when there is a presence of preexisting cells/microbes. The Golen Age of Microbiology 1857- 1914 Beginning with Louis Pasteur’s work, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs. Pasteur’s discoveries led to the development of aseptic techniques used in laboratory and medical procedures to prevent contamination by microorganisms. Pasteur showed that microbes are responsible for fermentation Fermentation is the microbial conversion of sugar to alcohol without air. Microbial growth is also responsible for the spoilage of food and beverages. Bacteria that use air spoil wine by turning it into vinegar (acetic acid) ○ This means that acetic acid bacteria thrive in the presence of oxygen (air) and can convert the alcohol of wine into acidic acid, an important component of vinegar. Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine. Pasteurization is the application of high heat for a short time to kill harmful bacteria in beverages. The Germ Theory 1835: Agonista Bassi showed that a fungus caused a silkworm disease. 1865: Pasteure showed that a protozoan caused another silkworm disease. 1840s: Ignaz Semmelweis advocated handwashing to prevent transmission of puerperal fever from one obstetrical patient to another. 1860s: Applying Pasteur’s work showing that microbes are in the air, can spoil food, and cause animal diseases, Joseph Lister used a chemical antiseptic (phenol) to prevent surgical wound infections. 1876: Robert Koch discovered that a bacterium causes anthrax and provided the experimental steps, Koch’s postulates, to demonstrate that a specific microbe causes a specific disease. Vaccination 1796: Edward Jenner inoculated a person with a cowpox virus, who was then immune to smallpox. Vaccination is derived from the Latin word vacca, meaning cow. The protection is called immunity. The Birth of Moden Chemotherapy: Dreams of a “Magic Bullet” Treatment of disease with chemicals is called chemotherapy Chemotherapeutic agents used to treat infectious diseases can be synthetic drugs or antibiotics. Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes. The First Synthetic Drugs Quinine from tree bark was long used to treat malaria. Paul Ehrlich speculated about “magic bullet” that could destroy a pathogen without harmnig the host. ○ 1910: Ehrlich developed a synthetic arsenic drug, salvarsa, to treat syphilis 1930s: Sulfonamides were synthesized. A Fortunate Accident-Antibiotics 1928: Alexander Fleming discovered the first antibiotic (by accident) Fleming observed that Penincillin fungus made an antibiotic, penicillin, that killed S. aureus. 1940s: Penicillin was tested cilincally and mass-produced Problems with Antimicrobial Chemicals Overuse can lead to resistance Some drugs can be toxic to humans ○ Especially antivirals Research used to overcome these problems has ushered in a Third Golde Age of Microbiology from the late 1980’s to the present. ➔ Bacteriology: is the study of bacteria. ➔ Mycology: is the study of fungi. ➔ Virology: is the study of viruses. ➔ Phycology: is the study of lgae. ➔ Parasitiology: is the study of protozoa and parasitic worms. Immunology Immunology is the study of immunity ○ Vaccines and interferons are used to prevent and cure viral diseases A major advance in immunology occured in 1933 when Rebecca Lancefield classified streptococci based on their cell wall components. Rebecca Lancefield (1895 - 1981) Rebecca Lancefield (1895 - 1981), who discovered differences in the chemical composition of a polysaccharide in the cell walls of many pathogenic streptococci. Virology Virology is the study of viruses Dmitri Iwanowski in 1892 and Wendell Stanley in 1935 discovered the cause of mosaic disease of tobacco to be a virus. Electron microscopes have made it possible to study the structure of viruses in detail. Recycling Vital Elements Microbial ecology is the study of the relationship between microorganisms and their environment. Bacteria convert carbon, oxygen, nitrogen, sulfur, and phosphorus into forms used by plants and animals. Sewage Treatment: Using Microbes to Recycle Water ❖ Sewage is 99.9% water, with a few hundredths of 1% suspended solids. ❖ Treatment of sewage removes undesirable components so water can be released or reused. Large solids are removed physically Microbes convert leftover liquid and organic materials into by-products such as carbon dioxide. Bioremediation: Using Microbes to Clean Up Pollutants Bacteria degrade organic matter in sewage Bacteria degrade or detoxify pollutants such as oil and mercury. ○ Meaning that naturally occurring bacteria to break down or degrade organic matter, including harmful substances like sewage and pollutants. Insect Pest Control by Microorganisms Microbes that are pathogenic to insects are alternatives to chemical pesticides. ○ Prevent insect damage to agricultural crops and disease transmission. Bacillus thurigiensis infections are fatal in many insets but harmless to animals and plants. ○ The bacteria produce protein crystals toxic to insects ○ The toxin gene has been inserted into some plants to confer insect resistance. Biotechnology and Recombinant DNA technology Biotechnology is the use of microbes for practical applications, such as producing foods and chemicals. Recombinant DNA technology enables bacteria and fungi to produce a variety of proteins, vaccines, and enzymes. ○ Missing or defecting genes in human cells can be replaced in gene therapy. ○ Genetically modified bacteria are used to protect crops from insects and from freezing.