BIO312 Microbial Life 2024 PDF

Introduction: Microbial Life Chapter 1 Microbiology (BIO312) Dr. Dorrity August 29th, 2024  Goal: To summarize microbial diversity, origins, and ecological interactions Outcomes: defining “microbe” and identifying outliers understanding...

Introduction: Microbial Life Chapter 1 Microbiology (BIO312) Dr. Dorrity August 29th, 2024  Goal: To summarize microbial diversity, origins, and ecological interactions Outcomes: defining “microbe” and identifying outliers understanding phylogeny and classification into 3 domains describing spontaneous generation and the experiments that disproved it differentiating between antiseptics, antibiotics, and vaccines What is a microbe? Microbe ”a microscopic, living organism” Microbe “a microscopic, living organism” Living: acquire nutrients replicate (on their own) respond to stimuli Microbe What about viruses? What about large microbes? Can they be multicellular? Prokaryotic vs. Eukaryotic?  Not all microbes are pathogens!!! Even though the news might make you believe they are Organizing Microbes Phylogeny: representation of evolutionary relationships between organisms Nomenclature: naming of organisms How to classify microbes??? Observing Microbes Robert Hooke observes microscopic organisms Antonie van Leeuwenhoek observes single-celled organisms Can classify microbes based on what they look like shape, size, structures, etc. Microbial Metabolism Photosynthetic Microbial metabolisms are super diverse Can classify microbes based on what they metabolize/synthesize (Ties to where microbes live)  FeO3 -> FeO4 Extremophiles an organism that lives in an environment normally hostile to life high salt (halophile) high heat (thermophile) high acidity (acidophile)  Microbes and Ecological Cycles Microbial metabolisms play a critical role in recycling of certain nutrients Soil bacteria (and rhizobial bacteria) fix atmospheric nitrogen into useable Microbial Genomes Genome: total genetic information in an organism’s chromosomal DNA track mutation rate certain genes are “clocks” 16S rRNA Culturing Bacteria Pure culture important for sequencing And identifying disease-causing agents Only 0.1% of bacteria are culturable Metagenome: collection of multiple genomes from environmental samples Kingdoms of Organisms Plants and Animals Haekal Plants and Animals and Monera Copeland Plants and Animals and Protists and Bacteria Whittaker Plants and Animals and Protists and Bacteria and Fung  Three Domains of Life Carl Woese George Fox Archaea are as distant from Bacteria as Eukarya is from Bacteria Where do microbes come from? Spontaneous generation: belief that living organisms can arise from no parental organisms Lazzaro Spallanzani: boiled broth, kept it in a sealed container, failed to grow microbes What is the problem with Spallanzani’s experiment? What is the problem with Spallanzani’s experiment? No airflow! Pasteur disproved* spontaneous generation *Tyndall really finished it, showed some broth kept growing because of heat resistant endospores (development of the How does life originate without some form of spontaneous generation? Early Earth, reducing atmosphere, lightning Miller and Urey: water, hydrogen, methane, ammonia, spark = amino acids Oró: hydrogen cyanide, ammonia, spark = nucleic acids  Medical Microbiology Germ theory of disease How do we know a given microbe causes a given disease?  Epidemiology: Koch’s Postulates study of the spread of infectious disease Robert Koch: chain of infection Antiseptics Chemical agent that kills microbes Ignaz Semmelweis and handwashing (chlorine) Joseph Lister and wound treatment (phenol) Antiseptics can’t be used internally, why? Antibiotics Chemical agents that specifically kill microbes Alexander Fleming discovered penicillin (by accident!) Most are naturally occurring Rise of antibiotic resistance Overuse and incomplete dosing Inoculation Variolation Using scrapings from Variola minor patients to protect against Variola major (smallpox) Practiced in India for centuries brought to Europe by Lady Montagu Vaccination Used extraction from cowpox patients to protect against smallpox Commonly known amongst milkmaids and farmers “Discovered” by Edward Jenner  Vaccines rely on immunity and the immune system  Goal: To summarize microbial diversity, origins, and ecological interactions Outcomes: defining “microbe” and identifying outliers understanding phylogeny and classification into 3 domains describing spontaneous generation and the experiments that disproved it differentiating between antiseptics, antibiotics, and vaccines