Belly Punchin Partner

Aquatic Microorganisms: Isolation and Identification Count - Part 2

NUMERICAL TAXONOMY

CLASSIC
phenotypic characters (morphology, nutrition, etc.).
some genotypes:% G + C, DNA-DNA hybridization
weighting of characters (dichotomous key)

- classical phenotypic phenotypic value taxonómicoCaracterísticas classical taxonomic value

Morphology: shape, size and staining
Nutrition and Physiology: phototrophs, chemotrophs, aerobic or anaerobic, temperature and pH optimum, alternative sources of C, N and smovil: type and arrangement of flagella

Other: pigments, cellular inclusions, antibiotic sensitivity, pathogenicity

- Features classic genotypic
............ G + C content

% G + C = G + C x 100
G + C + A + T
determination CsCl gradient, or chromatography thermal denaturation in prokaryotes
Wide range: 20 to 80%
little information for the taxonomic characterization

Exclusion criteria:% GC> 3, probably different species
% GC> 10, probably different genres
.............. DNA-DNA hybridization
- depends on the complete genome sequence
- useful in closely related organisms-determination by:
% hybridization ADN1 - ADN2

Δ Tm of the hybrid - is the current standard definition
species

NUMERICAL TAXONOMY Pooling
taxonomic units or taxa by numerical methods
is based on a large number of characters
Pesola Each character has equal similarity is based on the proportion of common characters

- phenotypic (not less than 60)
- similarity coefficient = a + d.
a + b + c + d

to: number of positive characters in both strains
b: number of positive character only strain 1
c: number of positive character only strain 2
d: number negative character in both strains given schema



Shewan et al. determinative proposed a scheme for identifying most bacteria isolated from marine environments.
Advantage: uses a small number of biochemical, morphological, cultural, staining and sensitivity to antibiotics, reason why it has gained widespread acceptance.
taxonomic schemes for marine bacteria Oliver (1982), Sawabe et al. (1995) and Jensen and Fenical (1995).


Sneath Identification Numerical taxonomy: The most logical way to identify bacteria is to compare the average similarity of microorganisms, using the principle adansoniano (equal weight to each character.)
Since then, several researchers have used numerical taxonomy to the study of marine strains. Unfortunately, this technique has its disadvantages:
Using reference strains that have generally been identified by classical methods Employment
much time and effort: It is recommended to study not less than 80 features
The need to consider numerous strains: over 100
The researcher's influence in the selection of features and provides interpretation of the variation resultadosNo (not phylogenetic)
Taxonomy Identification
numerical
Percentage of similarity (S%) = NS x 100 NS + N dN S = total number of positive features
N d = total number of different features
The results are expressed as a matrix
em TAXONOMY POLYPHASE
Consider:
% Guanine - Number of bases cytosine


InmunoelectroforesisProporción DNA Serotyping and nitrogen RNAContenido
antibiosis tests: Facing pathogenic bacteria in fish and shellfish

MOLECULAR TAXONOMY

PCR TECHNIQUE



PRESERVATION CROPS:

- Consider mortal nature of fresh cultures of bacteria:

- Reseeding fresh media periodically:
bacteria can be maintained in tubes of medium in which they have been grown by periodic steps to fresh media.
reseeding intervals vary with the type of microorganism
note: the appropriate culture medium, the proper temperature to keep the crops, and time to replant.
- Freeze: is very effective, they survive for more than 10 years
- glycerol broth at - 29 ° C (survive approximately 2 years) or dimethyl sulfoxide

- Preservation of cultures with mineral oil:
Many bacteria are well preserved by covering the agar in which are growing with sterile mineral oil. Some species have survived for 15 or 20 years.