Taxonomy of bacteria Flashcards
What system was found by Carl Linneaus to name microorganisms ?
Binomial system:
- generic name ( genus)
- Specific name (species)
What is a species?
A species is a group of organisms that can interbreed.
Plants, animals, organsims that are capable of reproduction
Most microorganisms reproduce …
asexually
Classification goes in 2 branches
Overall similarity (Phenetic) Evolutionary relationships (Phylogenetic)
What is a mutation?
is a change in the genome of an organism (nucleotide change, insertion, dele/on).
What is gene loss and horizontal gene transfer ?
acquisition of a whole new gene from another organism
What can be the effect of gene change?
- Silent (no effect)
- deleterious
- beneficial
What did Carl Woese do/discover?
- Sequencing of the small subunit rRNA (SSU rRNA ), 16 rRNA in prokaryotes and 18 rRNA in eukaryotes
- Established 3 domains of life: bacteria, eukarya, archea
- Provided a unified phylogenic framework
What is rRNA sequencing used for?
it is used to infer the phylogeny of prokaryotes and other microorganisms
What are the steps in sequencing rRNA ?
- isolate DNA
- amplify 16S gene
- Sequence
Eukaryotes are phylogenically closer too bacteria or archea?
Archea
What is endosymbiosis ?
hypothesis of origin of eukarya.
- Mito and chloroplast arose from symbiosis association between prokaryotes within another type of cell.
The transcription and translation machinery of eukaryotes is more similar to…
archea
The lipid and energy mechanism of bacteria is more similar to eukaryotes or archea?
eukaryotes
Give and exemple of predatory bacteria
Bdellovibrio
What is taxonomy? (3 things…)
- Nomenclature
- Classification
- Identification
What do predatory bacteria do?
- infect other bacterial cells
- acquire nutrients from the host
- does not grow on agar plate
- Gram positive bacteria are note infected
How do you compare rRNA?
- sEquencing the gene
2. Align the genes
what are the 2 endosymbiotic hypothesis?
- Nucleus first, then endosymbiosis
2. Endosymbiosis first, then nucleus
what does MLST stands for? and explain..
Multilocus sequencing typing
- Many genes,
- Comparison between sequencing of housekeeping genes
What are the 2 phylogenic analysis of archea?
- 16 rRNA
2. MLST
What are 2 methods of identification? and differences?
Dichotomous key :
- Easy way to identify pathogens ?
- APT strip–> flow chart to identify
- You have to know some info first….
Serotyping :
- Uses antibodies to determine characteristics of bacteria
What are the serotypes for LPS, Capsule and Flagella?
- LPS: O serotype
- Capsule: K serotype
- Flagella : H seotype
Give and exemple of filamentous actinobacteria? Describe your exemple.
Streptomyces
- hyphal growth
- produce sporophores –> dessication resistant spores
What is an exemple of Stalker bacteria?
Caulobacter
What type of bacteria does not use binary fission?
Caulobacter ( stalker bacteria)
What are characteristics of caulobacters?
- Marine
- Don’t do binary fission (stalk production)
- tip of the stalt produce the stickiest substance known
Give an exemple of obligate intracellular bacteria?
Chlamydia
What are characteristics of Chlamydia?
- live in host only
- Reticulate bodies –> active in host cell, become elementotary bodies
- Elementary bodies –> are going to be secreted , infectious particles
in what bacteria do we find reticulate and elementory bodies?
- Chlamydia
