LECTURE 4 Flashcards
how are bacterial species named?
binary combination of words in latin
genus and then epithet
genus name has capital letter
species epithet has lower case letter
species name italicised or underlined when written
contract the genus after the first use in text
what do the names of bacteria tell us about the species?
tells us about the
appearance
habitat
characteristic property
scientist name
what is the concept of a species in bacteriology?
collection of strains that share many stable properties and differ significantly from other groups of strains
assemblage of microorganisms so alike that there are no distinctions between them
how are species divided into strains?
clones but are genetically different
biovars: biochemical or physiological differences
morphovars: different morphology
serovars: different antigenic properties
what is the similarity constant and how is it calculated?
Sj
Sj= (number of similarities shared)/(number of similarities compared)
equal weight to all compared characters (different from eucaryotes)
Sj are used to create dendograms
what are some traditional characters that are used in comparison?
morphology:
shape
flagella
gram stain (positive or negative)
biochemistry and physiology:
aerobic or not
optimal temp
optimal pH
salt concentration
carbon source
fermentation properties (produces acids or gases)
serology:
antibodies against specific bacteria
phage typing: what bacteriophages can infect
host range (infect limited number of bacterial cells)
what are some methods to compare genomic characteristics?
indirect methods:
G+C content
melting point and density will be higher if you have more GC
DNA hybridization
total genome or probe hybridization
probe=target a specific gene
direct methods:
sequencing genes, rRNA, protein coding
gives phylogenetic relationships and real evolutionary links
what is another method to find out the species?
dichotomous keys
