ميحرلا نمحرلا الله مسب

GROWTH AND NUTRITION OF BACTERIA

Prof. Khalifa Sifaw Ghenghesh

Dept. of Medical Microbiology, Faculty of Medicine, Tripoli University Tripoli - Libya

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Growth:

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An Orderly Increase in All components of an Organism Multiplication >> Binary Fission.

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Measurement of Growth:

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Increase in Numbers Increase in Mass

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Batch Culture:

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Growth Curve:

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A Total Count.

A Viable Count.

1.

Lag Phase 2.

Log (logarithmic) Phase 3.

Stationary Phase 4.

Death Phase

GROUTH REQUIREMENTS AND BACTERIAL NUTRITION:

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Suitable Nutrients Must Be Supplied Physical Conditions Must Be as Near as Possible for the Organism Under Consideration

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BACTERIAL METABOLISM: Bacteria Require: An Energy Source A Carbon Source A Nitrogen Source Other Inorganic Salts and Accessory Growth Factors.

1.

Photo-autotrophs: 2.

Chemo- autotrophs 3.

Heterotrophs:

OXYGEN REQUIREMENTS AND METABOLISM: 1.

Obligate Aerobes 2.

3.

Obligate Ananerobes Facultative Anaerobes 4.

Microaerophilic Bacteria.

MEDIA FOR BACTERIAL GROWTH: 1.

2.

3.

General Laboratory Media:

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Peptone >> Amino acids Growth factors and inoorganic salts NaCl Synthetic Media Special Media:

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Selective media

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Indicator media Enrichment media

PHYSICAL CONDITIONS REQUIRED FOR GROWTH 1.

Influence of Oxygen and CO: 2.

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Influence Temperature: On Growth:

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Mesophilic bacteria Psychrophilic bacteria Thermophilic bacteria 3.

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On Viability: Influence of Moisture and Desiccation:

4. Influence of Hydrogen Ion Concentration (pH): 5. Influence of Light and other radiations: 6. Influence of Osmotic Pressure: 7. Influence of Mechanical and Sonic Stresses: