Lecture 17 Flashcards
Archaea
features in common with eukarya (rep, transcrip and transla), common with bacteria (size, no nucleus)
Highly diverese
Archaeal shape
cocci, rods common, 1-2 x 1-5 um for rods, 1-3 um in diameter for cocci
Archaeal cell morphology
coccus, branched, filamentous
archaeal cell walls
lack peptidoglycan, protein sheath
Archaeal membrane
unique lipids: isoprene units, ether linkages (rather than ester to glycerol)
Archaeal lipids
branched chain hydrocarbons attached to glycerol by ether linkages
Differences of archaeal flagella
powered by ATP (rather than H+), filament is hollow, hook and basal body hard to distinguish, growth occurs at base not end
Dna replication in Archaea
hybrid, single origin of replication, use same DNA polymerases as euks,
Transcription in archaea
occurs in cytoplasm, mRNA might be polycistronic, introns rare, use 1 RNA polymerase
Transcription in euks
nucleus, RNA moves to cytoplasm, genes split or interrupted, have exons
Transcription in euks (promotors)
RNA polymerase 2 must be recruited to a promotor, several elements define core promotor, euk and archaeal share sequences
Transcription factors (euk)
Rna polymerase 2 must be properly aligned on promotor, euks and archaea use transcription factors (they bind to DNA and recruit RNA polymerase)
Biogeochemical cycling
oxidation + reduction of substances carried out by living organisms/ abiotic processes, cycling pf elements in diff parts of ecosystem
Carbon cycle
carbon fixation - conversion of co2 into organic matter by microbes and plants, carbon enters common pool of organic matter that can be oxidized back into Co2
Methanogens
archaea that produce methane, largest group of cultured archaea, 16s rRNA
Methanogenesis
final step in decay of organic matter - generates CH4 (anaerobic environments), terminal electron acceptor is carbon
Reduction to methane
inorganic carbon can reduce anaerobically to methane, methane diffuses upward and is oxidized by other microbes
Importance of methanogens
wastewater treatment, produce significant amounts of methane (1 billion tons), clean burning fuel
microbial containment candidates
potential pathogens that can survive in water and represent serve health risks
Adenoviruses (waterborne)
resp illness sometimes GI diseases
Caliciviruses
cause self limiting nausea, vomiting, diarrhea
campylobacter jejuni
nausea, vomiting, diarrhea
Entero virus
polio, can cause CNS disorders
E.coli O157:H7
serve GI illness
helicobacter pylori
bacterium can cause gastic ulcers and cancer
Hep A
liver disease/ jaundice
Legionella pneumophila
hot water system, bacterial pneumonia when inhaled
mycobacterium avium
resp illness (w/ immunosuppresion)
Naegleria fowleri
protazoan found in warm surfaces and ground water (meningoencephalitis)
Salmonella enterica
GI illness
Shigella sonnei
GI illness, bloody diarrhea
Water purification
coagulation: chemical cogulats like alum and lime added
flocs: coagulated particles
rapid sand filters: physically traps particles
water disinfected: chlorine, ozone, UV
Indicator organisms
coliforms: gram -, ferment lactose, environment in feces of warm blooded animals, presence indicates fecal organisms may be present
Tests to detect coliforms
colilert defined substrate test
Membrane filter technique
Multiple tube fermentation test
Multiple tube fermentation test
- water sample added to lactose or lauryl tryptose broth - gas indicates co2 formation
- pos sample inoculated into green lactose broth
- Pos tubes inoculated into Eosin methylene blue plates (inhibits gram +)
- gram staining, microscopy
