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Molecular methods for bacterial picture show

Outline
Microorganisms Classical methods Molecular methods to study bacteria

1

Microorganisms
bed everywhere Represent more than 50% of the biomass on primer Beneficial & pathogenic Extremely diverse (the oldest life stool on earth)

Coccus

Bacillus

Coccobacillus Fusiform bacillus Spirillum Spirochaete

Vibrio

Cultivation as a classical bacteria study method
Cultivation of bacteria for: Obtaining pure cultures Identification Enumeration Liquid media

Specific (selective) media and harvest-home conditions are required

Solid media

Cultivation

Cannot enumerate both viable and cold Does not represent host-microbe interaction Difficult and time consume (fastidious growth conditions)

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Low culturability of bacteria
Habitat
Human gastrointestinal tract1 Seawater2 Freshwater2 Mesotrophic lake2 Unpolluted estuarine waters2 Activated sludge2 Sediments2 Soil2
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Culturability (%)
10 0.001 0.25 0.1 0.1 1 0.25 0.3
Vaughan et al. Curr. Is.Intest. Microbiol 1, 2000, 1-12 2 Amann, Rudolf I., et al. Microbiological reviews, 59 (1), 1955, 143-169

50 0.



1

1 3 15

A need for methods that circumvent culturing and practice reliable and fast analysis of microbial communities

Molecular characterization of microorganisms
Extraction of molecular markers directly from (environmental) samples for: Identification Enumeration
Cellular molecular markers: DNA RNA Proteins

Ribosomes consist of RNA

3

Bacterial identification utilise 16S rRNA
16S rRNA
(1540nt)

23S rRNA
(2900nt)

5S rRNA
(120nt)

Variable region

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2

3

4

5

6

7

8

9

Present in every bacterial cell
V6 V4 V5 V7

genetically stable
V8

V3

>200,000 sequences in databases Variable and conserved regions

V1

(identification and determining evolutionary exceed between bacteria)

V9 V2

16S rRNA folding

16S rRNA is a suitable tar sterilize for...If you want to get a full essay, order it on our website: Orderessay



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