History of Microbiology; Spontaneous Generation Nestor T. Hilvano, M.D., M.P.H.

Learning Objectives You should be able to: Describe the contributions of Leeuwenhoek. List six groups of microorganisms. Differentiate between prokaryotic and eukaryotic organisms. List and answer four questions that propelled research into what is called “the Golden Age of Microbiology.” Compare and contrast the investigations of Redi, Needham , Spallanzani, and Pasteur to disprove spontaneous generation. Discuss the significance of Pasteur's fermentation experiments to our world today. Identify the scientist whose experiments led to the field of biochemistry and the study of metabolism. Name two scientists whose work with vaccines began the field of immunology. List four major questions that drive microbiological investigations today (modern age of microbiology). Identify the field of microbiology that studies the role of microorganisms in the environment.

Introduction to Microbiology Branch of biology that deals with the study of microscopic forms of life. Microbes – short for microorganisms, single-cell life forms that can be seen through a microscope; some are beneficial and others are harmful Anton van Leeuwenhoek – made the first _____ microscope to examine the qualities of cloth. - reported protozoa (1674) & bacteria (1676) Compound b. Simple Electron d. dissecting

Microbes Classification Carolus Linnaeus – Taxonomic System, grouping similar organisms together 2 Types of Cell- Eukaryotes or Prokaryotes ___ unicellular, lack a nucleus (DNA in cytoplasm →nucleoid); bacteria and archaea ___ cells with nucleus (DNA in nucleus); fungi, algae, protozoa, 6 groups: Bacteria 2. Archaea 3. Fungi Protozoa 5. Algae 6. Little animals Viruses – smallest microbes, neither eukaryotes nor prokaryotes; obligate intracellular parasites Ex: Ebola virus is disastrous in humans, but the virus can be safely carried by its natural host (bats, monkey, chimp).

Fungi Differ from plants b/c they obtain food from other organisms; differ from animals b/c they have cell wall; include: a.) Molds – multicellular, grow as filaments (hyphae); reproduce by spores; cottony growth on cheese, bread, & jams b.) Yeasts – unicellular, oval; reproduce by budding Exercises: __ molds that produce penicillin __ yeasts which cause bread to rise and produce alcohol from sugar __ yeast infection in female a. Candida albicans b. Penicillium chrysogenum c. Saccharomyces cerevisiae d. Escherichia coli

Protozoa Single-celled eukaryotes, unicellular; most capable of locomotion Live freely in water, some cause disease Locomotive structures: ___ – cell extension during it’s travel; in Amoeba ___ – hair-like projection that beat rhythmically; in Paramecium ___ – whip-like cell in Trypanosoma (african sleeping sickness) a. cilia b. flagella c. pseudopodia

Algae Plant-like eukaryotes; photosynthesis Seaweeds and kelps, large algae Glasslike cell walls (diatoms) of algae Serve as food for marine animals and make chemicals used in microbiological growth media (solid agar culture)

Bacteria and Archaea Single-celled prokaryotes Reproduce asexually Bacteria - peptidoglycan cell walls; most are beneficial Archaea – cell wall composed of other polymers Exercises: __ What type of microbes is found in extreme environment (such as acidic hot spring, high saline lake, or oxygen depleted swamps)? a. Archaea b. Bacteria

Viruses Acellular, obligatory intracellular parasites Smallest microbes, neither eukaryotes nor prokaryotes composed of small amounts of genetic material (DNA or RNA) surrounded by a protein coat. Was discovered until the invention of EM in 1932 Ex: Ebola virus is disastrous in humans, but the virus can be safely carried by its natural host (bats, monkey, chimp).

4 Events during the Golden Age of Microbiology Is spontaneous generation of microbial life possible? What causes fermentation? What causes disease? How can we prevent infection and disease? 1. Proved that living things come from other living things 2. & 3. Microorganisms can cause fermentation and disease 4. Certain procedures and chemicals can prevent and cure infectious diseases

Is Spontaneous Generation of Microbial Life Possible? John Needham - boiled beef gravy and infusions of plant materials in vials, sealed with cork; revealed life force Francesco Redi - in sealed flask, decaying meat was kept from flies, maggots never developed Lazzaro Spallanzani - boiled infusion and sealed vials by melting their necks closed; reported results that contradicted Needham’s findings Louis Pasteur - father of microbiology; experiments with swan-necked flask, upright flask, no microbial growth Exercises: Which of the above scientists disproved spontaneous generation?

Pasteur’s Contributions: Father of Microbiology Began the field of industrial microbiology (biotechnology) – microbes are intentionally used to manufacture products. Discovered that bacteria ferment grape juice to produce acids; whereas yeast cells ferment grape juice to produce alcohol Pasteurization – use of heat to kill pathogens and reduce the number of spoilage of microbes in food and beverages (asepsis).

Buchner’s Experiments Demonstrated the presence of enzymes that promote chemical reactions Began the field of biochemistry and the study of metabolism

Infection and Disease Prevention Semmelweis (handwashing), Lister (antisepsis: phenol), Nightingale (hygiene), and Snow (public hygiene) investigations laid the foundation of infection control and epidemiology Edward Jenner, showed that vaccination with pus collected from cowpox lesions prevented smallpox (field of immunology). Later Pasteur, develop vaccines against fowl cholera, anthrax, and rabies. Ehrlich’s search for “magic bullets”, discovered chemicals effective against syphilis and sleeping sickness (field of chemotherapy).

Modern Age of Microbiology Biochemistry – study of metabolism; practical applications like design of herbicides and pesticides, diagnosis of illnesses, treatment of metabolic diseases, and design of drugs to treat disorders. Microbial genetics – study of inheritance in microbes Molecular biology – combines aspects of biochemistry, cell biology, and genetics to explain cell function at the molecular level Genetic engineering (recombinant DNA technology) – manipulation of genes for practical applications * Gene therapy – use of recombinant DNA to insert a missing gene or repair a defective gene in human. Environmental microbiology

Environmental Microbiology Studies the role microbes play in their natural environment - biodegradation - role in the causation of disease - control the spread such as sewage treatment, water purification, and sanitation measures

Homework Define terms: microbiology, molds, yeast, protozoa, algae, viruses, biotechnology, pathogen, microbes, spontaneous generation, bacteria, archaea, genetic engineering, and chemotherapy. Why was Pasteur considered as the Father of Microbiology? Name 3 scientist who disproved spontaneous generation. Name the contributions of Leewenhoek.