474-1 Intro and History of Microbiology

Lecture 1: An Introduction to Microbiology

A History of Microbiology

WHAT IS MICROBIOLOGY? Microbiology is the study of organisms too small to

be seen with the naked eye. Organisms/entities included in the study of

microbiology Viruses (acellular) Prions (acellular) Bacteria (procaryote) Archaea/Archaeobacteria (procaryote) Fungi (eucaryote) Protozoa (eucaryote) Algae (microscopic) (eucaryote) Helminths/Parasitic worms (eucaryote)

Basic Principles of Microbiology

Listed below are the fields of microbiology according to the group of organisms studied. Virology: the study of viruses Bacteriology: the study of bacteria Mycology: the study of fungi Protozoology: the study of protozoa Phycology/Algology: the study of algae Parasitology: the study of parasitic

organisms, traditionally identified as protozoa and parasitic worms

Basic Principles of Microbiology

Microbes are diverse.

Morphology (size, shape)

Ecology (environment, interactions with other organisms)

Nutrition (growth requirements)

Genetics

Disease types

Introduction to Microbiology

Microbiology is the basis of more specific disciplines

microbial genetics

molecular biology/genetic engineering/recombinant DNA technology

biotechnology

immunology


Microbiologist focus on understanding the microorganisms encountered daily.

They work to provide cures to major diseases, e.g. AIDS

Emphasis is placed on improving the quality of life

Gene therapy

Genetically modified organisms/foods

Vaccines (e.g. flu shoots)


Humans support a diverse microbial community

Normal flora (Resident microbiota) vs. transient microbiota

Bacteria: Gram positive vs. Gram negative

Fungi: yeast, dimorphic molds

Microscopic arthropods, e.g mites

Introduction to Microbiology A balanced normal flora on the skin and other

parts of the body help to protect from infection by pathogenic (disease-causing) micro-organisms

Bacteria in the intestine aid in digestion and help to synthesize vitamins that the body needs that it cannot make itself; e.g. vitamin K and some B vitamins

Probiotics: living organisms, mostly bacteria similar to the normal flora typically found in the digestive tract, that are used to support intestinal health.


Microorganisms are used in the production of food items:

Yogurt

Cheese

Wine and other alcoholic beverages

Bread

Vinegar

Soy sauce

Applied Microbiology: Food science


Microorganisms are used in industrial settings to produce chemicals

Acetone

Organic acids

Enzyme

Alcohols (e.g. ethanol and butanol)

Antibiotics

Applied Microbiology: industrial microbiology and biotechnology


Certain bacteria and algae are photosynthetic and provide benefits similar to plants in replenishing the oxygen supply.

Marine and freshwater microorganisms form the basis of the food chain in these environments.


Soil microorganisms help to break down wastes, convert atmospheric nitrogen into organic compounds, etc.

Bioremediation: microorganisms are used to clean up pollutants and hazardous materials (e.g. oil spills, radioactive wastes and trichloroethylene which is a highly toxic solvent used in dry cleaning.)

Introduction to Microbiology Disease

The study of how diseases are caused (etiology)

The study of how diseases are spread (transmission)

Identification of pathogen

Diagnosis

Treatment

Prophylaxis (prevention)

Applied Microbiology: Infectious Disease Medicine


Microbes are important in sewage treatment.

Organic liquids left behind after chemical and mechanical treatment are converted to carbon dioxide, nitrates, phosphates, etc. by bacteria and protozoa.

Basic Microbial Principles and Processes

Physiology

Growth

Metabolism

Fermentation

Respiration

Genetics

Replication

Plasmid Biology

Drug Resistance

Pathogenesis Virulence Infection and

Disease Parasitism Microbial Ecology Epidemiology Taxonomy and

Systematics


“Microbes make a critical contribution to the welfare of the world’s inhabitants by helping to maintain the balance of living organisms and chemicals in our environment.”

Important Pioneers in the Development of Microbiology

A Brief History of

Microbiology

Zacharias Jansen (1597): Dutch lens maker

(also Zaccharias Janssen)

Credited with the creation of the first compound (double lens) microscope; 20-30x magnification

One lens was close to the eyes (ocular) and the other was close to the sample (objective)

HISTORY OF MICROBIOLOGY

Robert Hooke(1665): English scientist

Microscopist

Improved Jansen’s compound microscope

First to publish drawings of microorganisms in the publication Micrographia

Demonstrated the fruiting bodies of mold



Robert Hooke (continued)

Observed thin slices of cork and noticed small, orderly arrangements.

He called the structured, orderly arrangements he observed under the microscope “cells” because they reminded him of the cells (or small, bare rooms) of monks.

His observations provided the basis for the cell theory


Antony van Leeuwenhoek (1632-1723)

Also Antonie van Leeuwenhoek

Dutch tailor, merchant and lens grinder

Microscope maker: Improved the lens used in microscopes; 270x magnification

Amateur scientist: First to accurately observe and describe microorganisms (1674)

Animalcules: bacteria and protozoa

Taken from samples of pond water, rain water, and material scraped from his teeth

HISTORY OF MICROBIOLOGY Carl von Linne (1701-1778)

Commonly known as Linnaeus; also Carolus Linnaeus

Swedish botanist

Created the binomial system

Binomial system

Is a two-word naming system

Genus name, then specific epithet (species name)

E.g. Escherichia coli, Staphylococcus aureus

Latin or Greek words are used for the names

Name is either descriptive or credits the discoverer

Escherichia: named after Theodore Escherich

Staphylococcus: From the Greek word, staphyle, for “grapelike cluster”.

HISTORY OF MICROBIOLOGY Binomial System

History of Microbiology Ferdinand Cohn (1828-1898)

German botanist, and microscopist

Studied algae and bacteria

Is known as the father of bacteriology

Best known for discovering endospores, based on his studies of Bacillus

Is credited with devising simple, but effective methods to prevent contamination of culture media

Use of cotton to stopper culture flasks

HISTORY OF MICROBIOLOGY Spontaneous generation/Abiogenesis Theory

Belief that living things arise spontaneously from non-living matter

People believed that:

moist grain gave rise to rodents

dust gave rise to beetles

mud gave rise to worms and frogs

rotten meat gave rise to “worms”, i.e. maggots.

Spontaneous generation

Proponents of the theory believed that all previously living organic matter contained a “vital force” that allowed life to arise from non-life.

Oxygen was also important for growth.

Important contributor: John Needham (English clergyman)



Biogenesis theory

Opposing theory to spontaneous generation that claims that living cells can only arise from pre-existing living cells


Important contributors to support the theory of Biogenesis

Francesco Redi (1626-1697)

Lazzaro Spallanzani (1729-1799)

Louis Pasteur (1822-1895)

John Tyndall (1820-1893)


Francesco Redi: Italian physician

Devised a set of experiments to demonstrate that rotting meat did not give rise to “worms” i.e. maggots (1688).

Lazzaro Spallanzani: Italian cleric and scientist

Performed a set of experiments to show that living organisms did not spontaneously appear in boiled broth of meat infusions (1765-1776)

Louis Pasteur: French chemist

Conducted experiments with swan-necked flasks and boiled infusions that helped to support the theory that life can only come from life.

John Tyndall: English physicist

A contemporary of Pasteur who performed experiments of boiled infusions and sealed flasks that were later opened to the air


The debate between spontaneous generation and the biogenesis theory finally ended in the 19th century with the formulation of the “Germ theory of Disease”

Germ theory of Disease the concept that human disease is caused by

microorganisms Important Contributors

Louis Pasteur Robert Koch



Louis Pasteur: French chemist and scientist (1822-1895)

“Pasteurization”

Important work with fermentation and putrefaction

Produced vaccines using attenuated strains of disease causing organisms

Created vaccines for rabies and anthrax.


Robert Koch: German physician (1843-1910)

Derived techniques for studying bacteria in vitro

The creation of nutrient broth and nutrient agar, media suitable for the culture and isolation of microorganisms obtained from human diseases

Especially ways to grow bacteria in pure culture (i.e. cultures that only contain one species of microorganisms).

HISTORY OF MICROBIOLOGY Robert Koch (1876)

Agar: used as a substitute for potato slices and gelatin.

Introduced to him through Fanny Angelina Hesse, the wife of Walther Hesse, one of Koch’s colleagues.

Petri dish: a container to hold the agar medium

An invention by Julius Richard Petri

HISTORY OF MICROBIOLOGY Introduced the concept of one organism-one

disease

Started the field of etiology: the study of disease causation

Koch formulated a series proofs to verify that a disease is directly caused by a specific microorganism

Koch’s Postulates: 1.The microorganism must be present in every

case of the disease but absent from healthy organisms

2. The suspected microorganism must be isolated and grown in a pure culture

3. The same disease must result when the isolated microorganism is inoculated in a healthy host

4. The same microorganism must be isolated again from the diseased host



Matthias Schleiden and Theodor Schwann

Formulated the cell theory (1837)that says

The cell is the fundamental unit of life.

All living things are made up of cells.

It is the site for all of the basic functions of living organisms.

Living organisms are considered cellular organisms.


Matthias Schleiden (1804-1881)

German botanist who in 1838 studied plants and realized that all plants were made from smaller building blocks or cells.

Theodor Schwann (1810-1882)

German zoologist and physiologist who discovered the enzyme pepsin in 1836. In 1839, he extended the tenets of the cell theory to animal cells. He believed that new cells were derived from pre-existing cells.


Edward Jenner: British physician (1749-1823)

The first (in Western culture) to develop a vaccine (1798)

He provided protection from disease by using a less virulent or attenuated version of the disease-causing microorganism: smallpox

From his experiments with smallpox/cowpox, we get the word “vaccination” and “vaccine”; vacca (latin)= cow

HISTORY OF MICROBIOLOGY Dr. Oliver Wendell Holmes: American physician

(1809-1894)

First observed that mothers who gave birth at home had fewer incidences of peurperal fever than mothers that gave birth in hospitals. (1843)

Determined that the disease was transmitted from patient to patient by doctors and nurses

Shares credit with Dr. Semmelweis

His observation pre-dated Semmelweis by three years

HISTORY OF MICROBIOLOGY Dr. Ignaz Semmelweis (1818-1865)

Hungarian physician working in Vienna, Austria

Observed that many hospitalized women died of a fever associated with childbirth (puerperal or childbed fever) (1847)

Showed the disease associated with childbirth was a result of physicians examining the women after performing autopsies

Instituted the policy of handwashing and observed a marked reduction in the number of deaths associated with this disease

Joseph Lister: British surgeon (1827-1912)

Known for improving surgical techniques to prevent wound infection (1865)

Introduced the concepts of:

antiseptic surgery using heat sterilized tools

the use of phenol which inhibits bacterial cell growth and kills bacteria

use of carbolic acid on bandages


Hans Christian Gram (1853-1938)

Published a paper describing the technique for staining bacteria (1884)

The Gram stain

Is a stain that differentiates bacteria into two groups based on the composition of their cell wall

Gram positive and Gram negative

This method is still used in microbiology today



Florence Nightingale (1820-1910) British nurse who introduced cleanliness and other

aseptic techniques into nursing practices.

Set standards for hygiene in hospitals

The use of scrubbing brushes for nurses when washing hands

Separated patient care locations from locations where clothes and used bandages were cleaned

Worked at removing unsanitary conditions from hospitals


Alexander Fleming: Scottish physician (1881-1955)

Discovered and described the first antibiotic: penicillin

The discovery of antibiotics was accidental (1928)

Penicillin is derived from the mold Penicillium notatum

Antibiotics are substances produced by both bacteria and fungi to kill other microorganisms

Documents

474-1 Intro and History of Microbiology