The History and Scope of Microbiology

QUIZ

Microbiology

**is the study of microorganisms usually less than 1mm in diameter which requires some form of magnification (Microscope) to be seen clearly.**

Isolation**, Sterilization, Culture in artificial media**

Techniques necessary to isolate and culture microorganisms.

Microbiology may be interested in specific types of organisms:

**Virology - viruses**

**Bacteriology - bacteria**

**Phycology - algae**

**Mycology - fungi**

**Protozoology - protozoa**

ROBERT HOOKE

stated that life’s smallest structural units were cells.

ANTONY VAN LEEUWENHOEK

\-First to observe living microbes

\-His single-lens magnified **50-300X magnification**

\-Between 1674-1723 he wrote series of papers describing his observations of bacteria, algae, protozoa, and fungi **(Animalcules)**

SPONTANEOUS GENERATION

Early belief that some forms of life could arise from “vital forces” present in nonliving or decomposing matter, abiogenesis.  In other words, organisms can arise form non-living matter.

LOUIS JABLOT

In 1670 Jablot conducted an experiment in which he divided a hay infusion that had been boiled into two containers: a heated container that was closed to the air and a heated container that was freely open to the air.  Only the open vessel developed microorganisms.  This further helped to disprove abiogenesis.

Schwann, Friedrich Schroder and von Dusch

**Air allowed to enter flask but only after passing through a heated tube or sterile wool.**

John Tyndall (1820-1893)

Omission of dust à no growth.  Demonstrated heat resistant forms of bacteria (endospores)

**LOUIS PASTEUR (1822 - 1895)**

\-Disproved spontaneous generation of microbes by preventing “dust particles” from reaching the sterile broth.

\-Showed microbes caused fermentation and spoilage.

**Oliver Holmes (1773 - 1843)**

**showed that sepsis could be transmitted by hands of medical student and may cause disease.**

**M. J. Berkeley (ca. 1845)**

**demonstrated that the Great Potato Blight of Ireland was caused by a Fungus.**

**Louis Pasteur (1822 - 1895)**

showed **that the pébrine disease of silkworms was caused by a protozoan parasite.**

Edward Jenner (ca. 1798)

Develop the first Vaccine and used a vaccination procedure to protect individuals from smallpox.

**Louis Pasteur**

**developed other vaccines including those for chicken cholera, anthrax, and rabies.**

Robert Koch

His criteria became known as Koch’s Postulates and are still used to establish the link between a particular microorganism and a particular disease..

Koch’s Postulates

**The causative (etiological) agent must be present in all affected organisms but absent in healthy individuals.**

Gelatin

N**ot useful as solidifying agent (melts at >28 ºC and some bacteria hydrolyze it with enzymes)**

Fannie Hesse

the wife of one of Koch’s assistants, proposed using agar.

Richard Petri

another of Koch’s assistants, developed the Petri dish.

Vaccination

**Inoculation of healthy individuals with weakened (or attenuated) forms of microorganisms, that would otherwise cause disease, to provide protection, or active immunity from disease upon later exposure.**

Pasteur and Roux

**they noticed that animals injected with attenuated cultures were resistant to the disease.**

JOHN TYNDALL (1820 – 1893)

In **1876** discovered that there were two different types of bacteria.

2 types of bacteria

Heat sensitive & Heat resistant.

Sterilization Process or Tyndallization

process of heating & cooling if repeated five times, can kill all the endospores.

FERDINAND COHN

German botanist also discovered “heat-resistant forms of bacteria”.  These bacteria are now termed endospores.

GOLDEN AGE OF MICROBIOLOGY

The period from 1860 to 1900. During this period, rapid advances, spear-headed by Louis Pasteur and Robert Koch, led to the establishment of microbiology as a science.

Pasteurization

This process kills bacteria in the alcohol by heat, thus preventing the formation of acetic acid (vinegar).

LOUIS PASTEUR

stated that diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc.

LOUIS PASTEUR

**“Father of bacteriology and immunology”**

Joseph Lister

**developed a system of surgery designed to prevent microorganisms from entering wounds – phenol (Carbolic Acid) sprayed in air around surgical incision.**

Robert Koch

In 1860 developed an elaborate technique to isolate & identify specific Pathogens that cause specific diseases.

PAUL EHRLICH

proposed a theory of immunity in which antibodies were responsible for immunity (Antitoxin).  In addition, he is known as the father of modern chemotherapy.

ALEXANDER FLEMING 1929

Discovery of Penicillin (first antibiotic)

Walter Hesse

Used Agar as a solidifying agent to harden media. Agar is extracted from seaweeds red algae.

Richard Petri

Used agar dish to provide a large area to grow.

Christian Gram

Staining method that demonstrate bacteria and distinguish between Gram positive and Gram-negative bacteria.

Raymond Sabouraud

Develop culture media to study yeast and molds.

Dimitri Ivanovski

Tobacco mosaic virus could pass through filters used to remove bacteria.

Selman Waksman

Discovered a number of antibiotic such as Tetracycline and Streptomycin. 

Ruska (1938)

First Electron Microscope

Electron Microscope

is capable of magnifying biological specimens up to one million times.

WATSON and CRICK, FRANKLIN, and WILKINS

determined the structure of DNA. 

George W. Beadle and Edward L. Tatum

**studied the relationship between genes and enzymes using the bread mold,** ***Neurospora.***

Salvadore Luria and Max Delbruck

**Demonstrated spontaneous gene mutations in bacteria (not directed by the environment).**

**Oswald T. Avery, Colin M. MacLeod, and Maclyn McCarty (1944)**

they provided evidence that deoxyribonucleic acid (DNA) was the genetic material and carried genetic information during transformation.

**two types of microorganisms:**

**Prokaryotes & Eukaryotes**

**Prokaryotes**

**have a relatively simple morphology and lack a true membrane-bound nucleus.**

Eukaryotes

**are morphologically complex and have a true, membrane-bound nucleus.**

Organisms can be divided into five kingdoms:

***Monera*** **or** ***Procaryotae, Protista, Fungi, Animalia, Plantae***