Bacteria diversity Flashcards
cyanobacteria
- larger than other bacteria
- all carry out oxygenic photosynthesis
- all are autotrophs
- photosynthesis in thylakoids
- have cells walls
- contain peptidoglycan
- gram negative cell wall
- lowest nutritional requirements of any organisms (primary producers)
- distributed in terrestrial, freshwater and marine habitats
Proteobacteria
- many most commonly encountered bacteria
- most metabolically diverse (chemolithotrophs, chemoorganotrophs, phototrophs, facultative organisms that switch from one metabolic lifestyle to another)
- 6 classes
- Includes pathogens and non pathogens
- gammaproteobacteria-many grow well in the lab and have becomes important research models and are metabolically and ecologically diverse
Firmicutes
- one of two phyla with gram positive cell walls
- low GC gram positives
- includes lactic acid bacteria- fermentation produces lactic acid as an end product
- and non lactic acid
Endospore forming Firmicutes
- The best studied genera of endospore formers:
- bacillus-aerobic endospore formers
- clostridium-anaerobic endospore formers
- endospore formers are found primarily in soil
- most are non-pathogenic saprophytic(plants or fungi that live on dead or decomposing matter) soil organisms
- however, some can be dangerous pathogens
Tenericutes: the mycoplasmas
- Phylogenitically related to gram positives, but they don’t have a cell wall
- gram negative
- often pleomorphic- the ability of some bacteria to alter their shape or size in response to environmental conditions
Actinobacteria
second phylum of gram positive bacteria
high GC gram positives
includes coryneform bacteria (club shaped morphology)
Actinobacteria: mycobacteriaum
- mycobacteria have a modified gram positive cell wall
- layer of mycolic acids outside peptidogylcan layer makes them acid-fast (stain)
filamentous actinobacteria: streptomyces
- genus of filamentous gram positives
- form branching hyphae and mycleia
- hyphae produces reproductive spores for dispersal- Conidia- not endospores
- most are obligate aerobes
- live in well aerated soils
- give soil its earthy smell-geosmins
- produces substances that kill or inhibit the growth of other microbes- antibiotics
Bacteroidetes
- large, heterogeneous phylum of gram negative bacteria
- aerobes and anaerobes
- few unifying characteristics
Chlamydiae
-gram negative cell wall type, but lack peptidogylcan
-obligate intracellular parasites
-unique life-cycle with two types of cells
elementary body
-small dense cell, resists drying
-allows infection of new host cells
reticulate body
-larger vegetative cells
-multiply insides an existing host but are not infective
Planctomyetes
- budding and appendaged bacteria
- protein stalk used for attachement
- lack peptidoglycan in the cell wall
- some have membrane-bound compartments inside the cell
hyperthermophilic bacteria
- there are several deeply branching phyla that consist of hyperthermophilic bacteria
- suggest that the last universal common ancestor (LUCA) may have been a hyperthermophile
deinococcus-thermus
-two famous species
thermus aquaticus
deinococcus radiodurans
