Introduction to microbiology.Morphology of microorganisms

Vinnitsa National Pirogov Memorial Medical University/ Department of microbiology

Microbiology is a great complex of biological sciences about microorganisms

Branches of microbiology Basic or general microbiology Industrial microbiology and biotechnology Pharmaceutical microbiology Agricultural microbiology Veterinary microbiology Sanitary microbiology (microbiology of food,

water, soil and air) Medical microbiology

Medical microbiology

Taxonomy of microorganisms

Classification Nomenclature (binominal

system ) Systematic

Ranks of hierarchical arrangement

Main methods of classification

Intraspecies classification

Biotype

Serotype

Phagotype

Present classification of microorganisms

Cellular microorganisms non-cellular microorganisms

Superkingdom

Eucaryotae Procaryotae

Kingdom

Animalia Fungi Eubacteriae

Protozoa

Kingdom

Vira

Canonical viruses

Non-canonical viruses

Methods of morphology investigation

Light microscopy :

Immersion microscopy

Dark-field microscopy

Phase-contrast microscopy Electron microscopy

Luminescent microscopy

Main morphological signs of micro-organisms

Shape Size Cell arrangement Tinctorial properties Structure:

CapsuleStructure of cell wallFlagellaEndospores

Cocci.

Micrococci

Diplococci

Tetracocci

Streptococci

Sarcinae

Staphylococci

Rod-shaped forms

Bacteria Bacilli Clostridia

Spiral-shaped bacteria.

Vibrio Spirilla Spirochaetes

Thread-shaped bacteria

Main differences of the cell structure

Type of cell procaryotes eucaryotes

size 1-10 µm 10-100 µm

genom

exhibited

Nucleoid is not separeted from cytoplasm

1 chromosome (circular)

Nucleus

Have a nuclear membrane

A few chromosomes (linear)

Mitochondria absent present

Apparatus Golgi absent present

Endoplasmatic reticulum

absent present

ribosome Within cytoplasm 70S

(50S+30S)

into ЕPR 80S

(60S+40S)

Cell wall peptidoglycane cellulose

endospores + —

Structure of the bacteria

Cell envelope:- capsule- Cell wall- Cytoplasmic membraneOutside appendages:- flagella- Pili or fimbriaInside structure:- cytoplasm- nucleoid- ribosomes- mesosomes- Intracellular inclusion

Features of the structure Gram-positive cell wall

Feature of the structure Gram-negative cell envelope

Flagella

Motile bacteria may be divided into:

1.Creeping

2.Swimming

• (1) monotrichous,

• (2) amphitrichous,

• (3) lophotrichous,

• (4) peritrichous

Pili or fimbriae

1. Common-pili

2. F – pili or sex-pili

Methods for flagella revealingDirect methods (microscopy)

Indirect methods

wet-mount

hanging-drop techniques

Intracytoplasmatic inclusions.

Volutin granules

EndosporesEndospores

Historical development of microbiology Period before microorganisms were seen Micrographic period (from the middle of 17th century

to the middle of 18th century ; A.van Leeuwenhoek ) Physiological period (19th century: L. Pasteur, R.

Koch) Immunological period (first part of 20th century:

G.Bordet, I.I.Metchnikoff, P.Ehrlich, D.I.Ivanowsky): development of immunology and the start of development of the virology)

Modern (now-day) period (development of molecular immunology, genetic engineering, immunochemistry, microbial genetics and other parts of microbiology)

Antony van Leeuwenhoek (1632-1723)

He was the first person who observed and described microorganisms (he named their as “animalcules”)

He constructed first microscope with magnification about 50 to 300 times

Louis Pasteur (1822-1895)

He established that fermentation was the result of microbial activity

He introduced techniques of sterilization and made steam sterilizer, hot air oven, and autoclave

He showed that microorganisms do not arise by spontaneous generation

He elaborated methods of pathogenic microorganisms attenuation

He developed rabies vaccine and anthrax one

Robert Koch (1843-1910) He elaborated methods of staining and cultivation of

microorganisms He discovered causative agents of anthrax (1877),

cholera (1883) and tubercle bacillus (1882) He proposed techniques for pure culture isolation He elaborated criteria for proving relationship between a

microorganism and a specific diseases (Koch's postulates) The microorganism must be present in every case of the

disease but absent in healthy organism The suspected microorganism must be isolated and grown in a

pure culture The same disease must result when the isolated microorganism

is inoculated into a healthy host The same microorganism must be isolated again from the

diseased host