Honors Microbiology

Chapter 1 – Scope of Microbiology

• I. Why Study Microbiology?– Microbes have a major impact on human health,

environment, and help maintain the balance of nature.

– Microbes play an important role in many of our foods and medicines

– The study of microbes provides insight into life processes in all life forms

Microbe Types

• Prokaryotes – 2 Domains/Superkingdoms

• Bacteria– Some pathogens– Science of Bacteriology

• Archaea– Environmental

extremophiles– Novel biochemistry

Eukaryotic Microbes

• Algae (Protozoa/Plants)– Photosynthetic– Aquatic– Science of Phycology

• Fungi (Kingdom)– Decomposers– Single or multicellular– Science of Mycology

Viruses (Acellular)

• Simple structure– Capsid– Nucleic acid

• Obligate intracellular growth• Science of Virology

• Smaller relatives– Viroids– Prions

Eukaryotic Parasites

• Protozoa (Kingdom)– Single celled– May be pathogenic– Science of Protozoology

• Helminths (Worms)– Microscopic life stages– Diagnosed microscopically– Sccience of Parasitology

• Arthropods– Cause/transmit disease

– Microbes are easily studied because:• Have relatively simple structures• Can be grown in large numbers• Can reproduce quickly

II. Scope of Microbiology

• The microbes – include the bacteria, algae, fungi, viruses and protozoa

• Other organisms studied – helminths (worms) and arthropods

• Microbiologists study a variety of areas:– Particular organisms– Processes or functions– Health-related– applications

Anthrax Bacteria

Algae

Athlete’s foot fungus

Giardia lambia (protozoa)

Guinea worm infestation

Arthropods as disease vectors

III. Historical Roots

• Mosaic laws found in the Bible involve basic sanitation practices that are still used today in preventive medicine.

• Greeks:– Set forth ethical standards for the practice of

medicine

• Hippocrates associated symptoms with illnesses and realized that disease could be transmitted via clothing and other objects

Hippocrates

• Thucydides observed that people who survived plague would not get the disease again (immunology)

Thucydides

• Romans:– Varro proposed that tiny animals entered the

body and caused disease.

• Lucretius cited “seeds” of disease in his written works

Lucretius

• Jews practiced ancient laws of sanitation and alternative types of medical treatments which helped them survive the Bubonic Plague.

• Development of the microscope:– Anton van Leeuwenhoek – first to make and use

lenses to observe living microorganisms– Electron microscopes – developed in the 1930’s

and 1940’s

Anton van Leeuwenhoek

First microscope

• Robert Hooke – first to build a compound microscope, and coined the term “cell”

Robert Hooke

Hooke’s microscope

• Electron microscopes – developed in the 1930’s and 1940’s

Electron Microscope

IV. Important scientists and their contributions to Microbiology

• Louis Pasteur:– Helped disprove the idea of spontaneous

generation– Developed the technique of pasteurization– Associated specific organisms with particular

diseases– Contributed to the development of vaccines

Louis Pasteur

• Robert Koch:– Identified the bacterium that causes anthrax, and

the bacterium that causes tuberculosis– Developed techniques for studying cells in vitro– Formulated a set of postulates to help establish

the Germ Theory of Disease– Conducted research on cholera, typhoid fever,

and sleeping sickness

Robert Koch

• Ignaz Semmelweis – worked to reduce childbed fever by establishing more sanitary practices in patient examinations

• Joseph Lister – ‘father of antiseptic surgery’, developed aseptic techniques, formulated carbolic acid (phenol)

Ignaz Semmelweis

Joseph Lister

• Edward Jenner – developed the vaccine for smallpox

• Elie Metchnikoff – discovered that certain cells in the body (“phagocytes”) could ingest microbes

Edward Jenner

• Martinus Beijerinck – first to characterize viruses

• Wendell Stanley – isolated RNA viruses• Hershey and Chase – isolated DNA viruses

Elie Metchnikoff

• Paul Ehrlich – suggested that chemicals might selectively kill invading microbes; considered the “father of chemotherapy”

• Alexander Fleming – discovered penicillin• Gerhard Domagk – developed sulfa drugs

Paul Ehrlich

Alexander Fleming

Gerhard Domagk

• Walter Reed – discovered the cause of yellow fever

• Selman Waksman – developed streptomycin and other antibiotics

Walter Reed

Selman Waksman