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MLS303 Part 2
Microbiology Systematics- Taxonomy, Nomenclature, Identification
43
Microbiology
Undergraduate 3
10/22/2012

Additional Microbiology Flashcards

 


 

Cards

Term

 

What are the three types of taxonomy?

Definition

Biologic

Numeric

DNA

Term
What are the three elements to any biological systematics?
Definition

Taxonomy

Nomenclature

Identification

Term
What do the suffix's "ales" and "aceae" AWLAYS refer to?
Definition

ales: order

aceae: family

Term
What is the purpose of Taxonomy?
Definition
  • It is to provide useful ways for identifying and comparing organisms.
  • Another goal is to asses the extent of diversity of different types of organisms.
Term

 

What is numeric taxonomy and what is usually used to chart it?

Definition

Numeric taxonomy is a Phenetic system that uses observable characteristics (gram stain, cell shape, motility, size, cell wall chemistry etc....) to group organisms


A Similarity Matrix is used to group the organisms by greatest number of characteristics in common and a dendogram is used to graphically display similarity coefficients. 

 

Term

 

What is a phenon?

Definition

it is a group of organisms with great similarity


*In numeric taxonomy >%80 similarity= same species

Term
What is Phylogenetic (Genotypic) system of taxonomy?
Definition

This groups organisms based on shared evolutionary heritage. 

*DNA and RNA sequencing techniques are considered to give the most meaningful phylongenies

Term
What is the G + C ratio?
Definition

How much Guanine and Cytosine in a  strand of DNA 

Determined by: G+C/ G+C+T+A

Term
How do we determine G+C amount?
Definition
DNA with greater G+C content have more hydrogen bonds and the strand seperates at a higher temperaure which equals a higher melting point. When the DNA strand is slowly heated the midpoint of the rising curve gives the melting temperature, which is a direct measure of G+C content. 
Term
What is the average Genome size for bacteria?
Definition
between 1 x 10^9 and 4 x 10^9 daltons per cell of DNA
Term

 

What is the purpose of a thermalstability test?

Definition
to figure out what temperature is best to stick DNA acid and bases together
Term
What are molecular species?
Definition

o   two organisms are considered to be in the same molecular species if they exhibit 70% or greater relatedness and the related sequences contain 5% or fewer unpaired bases

Term

 

What is Multilocus Sequence Typing (MLST)

Definition

the seqeuncing and comparison of 5-7 housekeeping genes done to prevent misleading results from analysis of one gene introduced by lateral gene transfer.

** also used for microbial classification and determination of phylogenetic relationships

Term
What are restriction enzymes used for?
Definition

·      use restriction enzymes to recognize specific nucleotide sequences

·      repetitive sequences amplified by the polymerase chain reaction

o   amplified fragments run on agarose gel, with each lane of gel corresponding to one microbial isolate

§  pattern of bands analyzed by computer

Term
Why is amino acid sequencing useful? Which protiens are found useful?
Definition

 a.a. sequencing of a protien is a reflections of mRNA seqeunce and therefore of the gene which encodes that protien. 

[cytochrome, histones, and heatshock proteins provided relevant taxonomic and phylogentic info]


Term
What are oligonucleotide signature sequences?
Definition
short, conserved nucleotide sequences that are specific for a phylogentically defined group of organisms. 
Term

when comparing rRNA sequences between 2 organisms, their relatedness is represented by an associatin coefficient of Sab valuethe higher the Sab value…..

 

Definition
the more closely related the two organisms are. 
Term
What is the difference between a "lumper"and a "splitter"...referring to dendograms...
Definition
splitter thinks that every difference matters and lumpers think organisms at least 92% similar are in one species.
Term

 

Who was Carl Linne (Carlus Linnaeus)?

Definition
He was a physician from swedan who developed the system of classification of plants based on number of stamen and carpels but one of his greatest contributions was the binomial system which we stil use today.
Term
What is a colloquial name?
Definition
It is the informal/common name. We do not used this becuase it is unreliable and miscommicative
Term
What are some of the the ways of organisms are named?
Definition

By:

  1. Discoverer
  2. Habitat
  3. Morphology
  4. Physiologic characteristics
  5. Pathogenicity
  6. Cultural Characteristics
  7. Pigmentation
Term
What does axenically pure mean?
Definition
less than 2 species
Term
In Indentification..What are some methods of Isolation?
Definition
  1. Streak plate - serial dilution on plate
  2. Pour Plate various colonies in molten agar (45-55 C)
  3. Colony Subculure - transfer colony from one environment to another
  4. Special Indentification Methods: Spore vs. veg cells (85 deg celsius, 5 min, kills veg but not spores) Add antimicrobials (screen out certain organisms) add dyes instead of antimicrobials (CV, brillant green), serial dilutions, single cell isolator (research lab)
Term
What is the First Biochemical test in Identification?
Definition

Gas Environment (second test in Identification)

Are they strict aerobes?

microaerophiles? facultative anaerobe? etc?

Term
What is the next step in identification after gas enivornment identification?
Definition

Step 3- Microscopic & Macroscopic Mophology

Determine colony formation, bacterial shape, on unadulturated organisms (close to orginal environment as possible)

Term
What tests are done for the Biochemical Characteristics of Microbial Identification?
Definition

1.Carbohydrate Dissimilation: Fermentation, Voges-Prokauer, and Fermentation and Proteolysis of Milk.


2. Proteolysis- Nutrient gelatin, gelatin hydrolysis, H2S production, Indole production, Nitrate Reduction, and rapid tests

Term
In the Carbohydrate Dissimilation test what are the 3 things used in the test for fermentation?
Definition

1. Durham Tube

2. Phenol Red broth base

3. Specific Carbohydrate

Term
In the Carbohydrate Dissimilation test what is the voges proskauer determine? 
Definition
Determine the amount of Acetylmethylcarbinal (AMC) using Barrits Reagent
Term
In the Carbohydrate Dissimilation test what usually is used and what happens in the fermantation and proteolysis of milk?
Definition
litmus milk is used and it is a acid reaction with protien precipitation and lipid hydrolysis
Term
In proteolysis detection how is the nutrient gelatin test preformed?
Definition

Nutrient broth + 10% gelatin incubated at 20C or 35C (melts at this temp so always read at 20C)

read as liquifiers, weak liquifiers, or non liqufiers

Term

In proteolysis detection How is the gelatin hydrolysis test preformed?

Definition

petri dish with nutrient gelatin, add frazier glacial acetic acid/ HCl-HgCl2 after innoc. and incub. then look for clearing zone

 

Term

In proteolysis detection how is the H2S production test performed?

Definition

reduction of thiol(sulfur containing) AAS

add Pb or Fe, it will turn black

 

Term

In proteolysis detection how is the indole test performed?

Definition

the trytophan will reduce to Indole + pyruciv acid

detect indole with Kovacks reagent

-n-amyl alcohol

-HCl

-PABA

you will get a red color

Term

In proteolysis detection how is the nitrate reduction test performed?

Definition

in a liquid media with a peptone to start it. 

Na, KNO2

(can organisms use nitrate as H acceptor?)

Term
Why are serologic characteristics tested for in Indentification of organisms? 
Definition

·      due to ultrastructure most microorganisms are capable of acting as antigens to the human immune system

Term
Why are pathophysiologic characteric tests done in identification?
Definition

even with all the previous test, sometimes the microorganisms still cant be identified so they innoculate an animal (kochs 3rd postulate)



issues with this are: time, cost, and space

Term
What is Phage testing in Identification of microorganisms?
Definition

-because bacteria are able to have their own parasites, bacteriophages, this test is done

**it needs to be narrowed down to 2 bacterias

-bc it is very host specific, you place the bacterias in a petri dish, add the bacteriophage that targets one, and if it "eats" the bacteria, the bacteria is host specific for that bacteriophage

Term

 

What is DNA  probe/Homology in Identification of microorganisms?

Definition

to be able to tell the organisms apart by their DNA

-need to have a good idea what you are looking for, a specific reason why

-some tests/labs may start with this

Term
List, in order of use, the methodologies used in the identification of bacteria:
Definition
  1. Isolation
  2. Gas environment
  3. Microscopic & Macroscopic Morphology
  4. Biochemical Characteristics
  5. Serologic Characteristics
  6. Pathophysiologic Characteristics
  7. Phage Testing
  8. DNA probes/homology
  9. PCR
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