MICROBIOLOGY - INTRODUCTION

2017-09-08T03:25:00.002-07:00

MICROBIOLOGY:

Deals with micro-organism and their studies. Or,

The study of organisms too small to be seen by eyes.

BRANCHES:

1. Bacteriology – deals with bacteria

2. Parasitology – deals with parasites

3. Virology – deals with virus

4. Mycology – Deals with fungi

5. Immunology – deals with immune system or host defense system of the body.

MICRO-ORGANISM:

It is the smallest living creature which is “a cellular” or multicellular organism which is microscopic or sub-microscopic in nature.

Ø A cellular- virus

Ø Unicellular-bacteria

Ø Multicellular– fungus , algae

Ø Microscopic- bacteria, algae

Ø Submicroscopic (too small to be seen by ordinary light microscope.) - virus, rickettsia

CLASSIFICATION OF ORGANISM:

1. Plant

2. Animal

3. Protest

i) Eukaryotes

ii) Prokaryotes

BENIFICIAL EFFECT OF MICROBES:

1. Production of nutrition and energy

2. Decomposition

1. Production of foods, drugs, and vaccine(recombinant DNA vaccine from virus)

2. Bioremediation – use of metabolism of microbes to remove pollutants.

HARMFUL EFFECT OF MICROBES:

1. Microbes play a great role in genesis of disease.

IMPORTANT NAMES IN MICROBIOLOGY:

ANTONIE PHILLIPS VAN LEEWENHOEK:

· First to observe living microbes.

· Invented simple light microscope.

· Father of microbiology, also known as father of microscope.

LOUIS PASTURE:

· Disapproved theory of spontaneous generation of microorganism.

· Showed microbe causes fermentation and spoilage.

ROBERT KOCH:

· Established a sequence of experimental steps to show specific microbe causes specific disease.

· Identified cause of anthrax, tuberculosis and cholera.

· Developed pure culture methods.

· Father of bacteriology.

KOCH’S PROSTULATE:

· The organism should be associated with a specific disease and not found in healthy individual.

· The same organism should be isolated in pure culture from the lesion.

· It produces the same disease in susceptible animal.

· The same organism should be isolated from the lesion produced in susceptible animal.

LIMITATIONS:

· Many microbes do not fulfill the criteria as-

Ø Virus cannot be grown in cell free media.

Ø Treponema pallidum and Mycobacterium leprae cannot be grown in artificial culture media.

Ø Some microbes cannot produce disease in experimental animal e.g., Neisseria gonorrhea.

Ø Some disease may be caused by mixed infection with more than one microbes.

TOXONOMY:

It is the scientific method of organizing, classifying and naming living things. Levels of classifications are:

§ Domain

§ Kingdom

§ Phylum

§ Class

§ Order

§ Family

§ Genus

§ Species

VIRUS -ACELLULAR:

ü Have no nucleus

ü Acellular –

No cytoplasm so they depend on host cell to provide machinery for protein synthesis and energy generation.

They contain either DNA or RNA but never both.

Replicate by producing many copies if their nucleic acid and protein and resemble into multiple progeny virus.

PROKARYOTES:

Pro: primitive; karyotes: nucleus

They are cells having a primitive nucleus or nucleoid consisting of a single molecule of loosely organized DNA lacking nuclear membrane, nucleolus, nucleoplasm and mitotic apparatus.

Example: Bacteria

EUKARYOTES:

Eu: true; karyotes: nucleus

They are the cell having a true nucleus with multiple chromosome, nucleolus and nucleoplasm surrounded by a nuclear membrane and using mitotic apparatus for their division.

Example:

Human cell, protozoa, fungi, helminths.

MOTILITY:

· Most protozoa and some bacteria are motile whereas virus are non-motile.

· Protozoa contains three organs of locomotion: flagella, cilia and pseudo pods . The motile bacteria move only by flagella.

MBBS NOTES

MICROBIOLOGY - INTRODUCTION

BRANCHES: