General Microbiology

Nickolas V. Kapp Ph.D

What is a Microbe

• Smaller than 0.1mm

• Includes bugs, things, germs, viruses, protozoan, bacteria, animalcules, small suckers

Nomenclature

• Carolus Linnaeus (1735)

• Genus species

• By custom once mentioned can be abbreviated with initial of genus followed by specific epithet. E. coli

• When two organisms share a common genus are related.

Why study Microbiology

• Microbes are related to all life.– In all environments– Many beneficial aspects– Related to life processes (food web, nutrient

cycling)– Only a minority are pathogenic.– Most of our problems are caused by microbes

Microbes in research

• 10 trillion human cells 10x this number microbes

• Easy to grow• Biochemistry is

essentially the same• Simple and easy to

study

Diversity of Microbes

• Bacteria-single celled prokaryotes

• Protozoa-eukaryotic, single celled, colonial, many ways of nutrition

• Fungi- absorb nutrients, single celled filamentous

• Viruses-acellular entities

• Others- worms, insects

A timeline of Microbiology

• Fig 1.4• Some highlights

– 1665 Hooke– 1673 van Leeuwenhoek’s microscopes– 1735 Linnaeus Nomenclature– 1798 Jenner vaccine– 1857 Pasteur Fermentation– 1876 Koch germ theory of disease

The Golden Age of Microbiology

• 1857-1914

• Beginning with Pasteur’s work, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs

• Pasteur showed that microbes are responsible for fermentation.

• Fermentation is the conversation of sugar to alcohol to make beer and wine.

• Microbial growth is also responsible for spoilage of food.

• Bacteria that use alcohol and produce acetic acid spoil wine by turning it to vinegar (acetic acid).

Fermentation and Pasteurization

• Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine. This application of a high heat for a short time is called pasteurization.

Fermentation and Pasteurization

Figure 1.4

• 1835: Agostino Bassi showed a silkworm disease was caused by a fungus.

• 1865: Pasteur believed that another silkworm disease was caused by a protozoan.

• 1840s: Ignaz Semmelwise advocated hand washing to prevent transmission of puerperal fever from one OB patient to another.

The Germ Theory of Disease

• 1860s: Joseph Lister used a chemical disinfectant to prevent surgical wound infections after looking at Pasteur’s work showing microbes are in the air, can spoil food, and cause animal diseases.

• 1876: Robert Koch provided proof that a bacterium causes anthrax and provided the experimental steps, Koch’s postulates, used to prove that a specific microbe causes a specific disease.

The Germ Theory of Disease

• Treatment with chemicals is chemotherapy.

• Chemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibiotics.

• Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes.

• Quinine from tree bark was long used to treat malaria.

• 1910: Paul Ehrlich developed a synthetic arsenic drug, salvarsan, to treat syphilis.

• 1930s: Sulfonamides were synthesized.

The Birth of Modern Chemotherapy

• 1928: Alexander Fleming discovered the first antibiotic.

• He observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus.

• 1940s: Penicillin was tested clinically and mass produced.

The Birth of Modern Chemotherapy

Similar to Figure 1.5

• Bacteriology is the study of bacteria.

• Mycology is the study of fungi.

• Parasitology is the study of protozoa and parasitic worms.

• Recent advances in genomics, the study of an organism’s genes, have provided new tools for classifying microorganisms.

• Proteomics is looking at the gene products

Modern Developments in Microbiology

Principles of Microscopy

• Metric units (table 3.1)– Micrometer– Nanometer– angstrom

Compound light microscopy

• Basic parts– Eyepieces (ocular lens)

– Base

– Condenser

– Iris diaphragm

– Objective lens

– Body tube

– Mechanical stage

– Adjustment knobs

Magnification

• Calculation:– Objective power x ocular power = total power

• Parafocial

• Paracentric

• Microscopic measurement– Micrometer? Why must we calibrate it?

Modern Developments in Microbiology

• Diagnostics

• Prevention

• Use as a tool

• Surveys and vigilance

What you should know?

• What are microbes?

• What types of microbes?

• Some history Highlights

• The Magic Bullet

• Microbes and human Welfare

• Microbes and Human Disease

• The CDC