Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
85 Cards in this Set
- Front
- Back
|
what are the classic traits used to identify and group microorganisms?
|
-presence of thick vs. thin cell wall (gram stain)
-presence of endospores -cell morphology (shape) -cell arrangement (group structure) -biochemical test (metabolic pathways, enzymes) |
|
|
what is a gram positive cell?
|
wall is thick layers of peptidoglycan that are held together by teichoic acid molecules
stains purple |
|
|
what is a gram positive cell?
|
wall is a thin layer of peptidoglycan covered by an outer membrane, which contains lipopolysaccharides (lps) or endotoxin. the periplasmic space is the compartment between the inner and outer membrane.
stains pink |
|
|
what are common cell shapes?
|
coccus: round berry shape
bacillus: rod shaped vibrio: bent rod spirillum: thick helical shape spirochete: very skinny helical shape coccobacillus: hard to say |
|
|
what are common cell arrangements?
|
strepto: chains
staphylo: a bunch tetrads: groups of 4 sarcina: groups of 8 diplo: two palisades: v-shaped |
|
|
explain classification based on gene sequences (esp. rRNA genes)
|
analysis of rRNA sequence data is useful for determining relationships between organisms having ribosomes (everything except viruses, viroids, prions)
based on genotypic data rather than phenotypes data is analyzed by a computer using mathmatical algorithms that remove human bias pioneering work was done by carl woese at illinois |
|
|
what are the similarities between archaea and bacteria?
|
-prokaryotic cell: no nuclear membrane, one circular chromosome
-70S ribosomes -most have cell walls some species stain purple and others end up red in the gram stain |
|
|
what are the differences between archaea and bacteria?
|
-ribosomal RNA sequence data
-archaeal cell walls lack peptidoglycan (no N-acetyl muramic acid) archaeal cytoplasmic membrane lipids have branched chain fatty acids that may extend through the membrane -the initial amino acid in protein synthesis in archaea is methionine rather than formyl-methionine, which is used in bacteria -archaeal RNA polymerase is similar to eukaryotic RNA pol. II -archaeal flagell are simple protein threads that rotate like those of bacteria, but they are very different. archaea flagella are not hollow tubes, they are solid. assembly differs from bacterial flagella too. |
|
|
how are archaea cell walls different from bacteria cell walls?
|
resistant to lysozyme, penicillins and vancomycin
vary among taxa (some stain purple, some red in gram stain) composed of a variety of compounds (proteins, glycoproteins, lipoproteins, and polysaccharides, but NOT peptidoglycan, they don't use n-acetyl muramic acid) |
|
|
what is pseudomurein?
|
is a cell wall polymer found in some species of archaea that is similar to peptidoglycan in that it consists of sugar chains that are cross linked by amino acid chains
differs from peptidoglycan in that it contains n-acetyl-l-talosaminuronic acid instead of n-acetyl-muramic acid, the cross-linking chains contain only l-amino acids, and the linkages of the sugar polymer are B(1-->3) rather than B(1-->4) linkages that are seen in bacteria peptidoglycan |
|
|
are there any archaea known to be human or animal pathogens?
|
no
|
|
|
what are subcategories of archaea?
|
methanogens
extremophiles |
|
|
what are extremophiles?
|
thermophiles: grow at temperatures over 45*C
hyperthermophiles: grow at temperatures over 80*C e.g. sulfolobus grows best at 75*C at a pH of 2.5 and is an obligate aerobe pyrodictium grows best at 105*C at pH of 6 and is anaerobic not all thermophiles are archaea, not all archaea are thermophiles |
|
|
what are methanogens?
|
obligate anaerobes that produce methane
substrates for methanogensis include: co2 + h2, methanol and various organic acids some methanogens are thermophiles: -methanogens convert organic wastes in pond, lake, and ocean sediments into methane and co2 -methanogens make gas in the gut of cows and grass eating animals -methanogens play an important role in the anaerobic digestion of organic wastes in sewage treatment e.g. methanopyrus, methanobacterium |
|
|
what are halophiles?
|
extremophiles
grow at extremely salty environments habitats are more than 9% NaCl (sea water is .9%), some can survive at 35% many make red-orange pigments that absorb light energy and protect from UV eg. halobacterium, halococcus use sunlight to produce PMF that is used to make ATP lack chlorophylls or bacteriochlorophylls makes bacteriohodopsins (purple-red pigments) rhodopsinprotein helps protect halococcus from the extreme salinity of their natural environments |
|
|
how many phyla are bacteria broken into?
|
23 based on 16S rRNA sequence data
|
|
|
what are deeply branching bacteria?
|
thought to be similar to very earliest life forms
eg. Aquificaeles species, hyperthermophyllic chemoautotrophic anaerobes, derive energy and carbon from inorganic sources, habitat includes hot mineral springs also Deinococcus radiodurans multiple copies of the chromosome and radiation absorbing pigments allow it to endure exposure to extremely high doses of ionizing radiation they have an outer membrane like gram negative bacteria but stain purple in gram stain |
|
|
what are phototrophic bacteria?
|
-blue green bacteria (cyanobacteria, blue-green algae)
-green sulfur bacteria -green nonsulfur bacteria -purple sulfur bacteria -purple nonsulfur bacteria |
|
|
oxygenic photosynthesis in cyanobacteria
|
12h2o + 6co2 --> c6h12o6 + 6h2o + 6o2
plant chloroplasts are thought to have evolved from endosymbiotic cyanobacteria |
|
|
anoxygenic photosynthesis in sulfur bacteria
|
12h2s + 6co2 --> c6h12o6 + 6h20 + 12s*
|
|
|
what is low g + c gram-positive bacteria?
|
DNA contains more A=T basepairs than G=C basepairs
|
|
|
examples of low g + c gram-positive bacteria are?
|
clostridium
bacillus mycoplasma listeria lactobacillus streptococcus enterococcus staphylococcus |
|
|
what is high g + c gram-positive bacteria?
|
DNA contains more G=C basepairs than A=T basepairs
|
|
|
what are examples of high g + c gram-positive bacteria?
|
corynebacterium
mycobacterium actinomycetes |
|
|
what is clostridium?
|
meads club-shaped
anaerobes (many are obligate anaerobes that die in the presence of o2) produce heat resistant endospores they have a wide variety of fermentative pathways such as acetone-butanol production many produce and excrete potent toxins |
|
|
what are examples of clostridium bacteria?
|
clostridium botulinum
clostridium tetani clostridium perfringens clostridium difficile |
|
|
what is clostridium botulinum?
|
natural habitat is anaerobic sediments in ponds/soil
produces a potent neurotoxin that causes flaccid paralysis has been involved in large duck die offs grows in contaminated canned food most cases of botulism are due to ingestion of toxin botulism toxin is denatured by cooking may infect the stomachs of infants and produce toxin in vivo spores are common in honey botox is used therapeutically to relax facial muscles A-B type toxin enters host cells and enzymatically inactivates nerotransmitter releasing mechanisms |
|
|
what is clostridium tetani?
|
natural habitat is anaerobic soils layers and sediments
produces a toxin that causes rigid paralysis infects wounds and produces toxins in vivo tatanus vaccine is a toxoid that provides immunity to toxin |
|
|
what is clostridium perfringens?
|
spores are common in soil
wound infection causes gas gangrene produces a number of necrotizing toxins that kill tissues |
|
|
what is clostridium difficile?
|
may be found in low numbers in the human gut
naturally resistant to several antibiotics may multiply in patients on antibiotic therapy produce toxins may cause antibiotic induced diarrhea |
|
|
what is bacillus?
|
means rod
aerobes or faculative heat resistane endospores |
|
|
what are some examples of bacillus?
|
bacillus anthracis
bacillus stearothermophilus bacillus thuringiensis bacillus licheniformis |
|
|
what is bacillus anthracis?
|
primarily an herbivore disease (sheep/cattle esp.)
problem in nations where animal vaccination is not practical virulence factors include: a capsule made of glutamic acid and toxins (edema factor, lethal factor, protective antigen) variations: inhalation anthrax, cutaneous anthrax, gastrointestinal anthrax |
|
|
what is inhalation anthrax?
|
initial flu-like symptoms
threatment is often too late to save the patien because the toxins are enzymes, even if the bacteria are killed the toxins keep on working to kill the patient very high mortality rate in untreated cases |
|
|
what is cutaneous anthrax?
|
infects minor wounds
necrotic effects on surrounding tissues AKA: wool sort's disease untreated mortality rate is 20% |
|
|
what is gastrointestinal anthrax?
|
infects gut due to eating contaminated meat
|
|
|
what is bacillus stearothermophilus?
|
a thermophile that is involved in hay spoilage
wet hay can lead to barn flies due to the heat released by microbial metabolism |
|
|
what is bacillus thuringiensis?
|
produces a toxin that kills insects but does not harm mammals
used as an organic method of controlling insect pests |
|
|
what is bacillus licheniformis?
|
synthesizes bacitracin - an antibiotic that inhibits peptidoglycan synthesis by interfering with the movement of precursor groups through the cell membrane to the cell wall
a common soil bacterium capable of reducing nitrate |
|
|
what is mycoplasma?
|
aka ureoplasm
very small (.2-.8) lack cell walls ergosterol is cytoplasmic membrane can be grown in acellular cultures eg. mycoplasma pneumonia (atypical pneumonia) |
|
|
what is listeria?
|
gram positive
no endospores L. monocytogenes intracellular parasitte that can move from host cell to host cell directly, without going through the blood, outbreaks associated with contaminated cheese |
|
|
what is lactobacillus?
|
gram positive, non-spore rods
ferment sugar to produce lactic acid l. bulgaricus and others used to make yogurt and cheeses |
|
|
what is streptococcus?
|
gram positive cocci
catalase negative and come in chains s. pyogenes causes strep throat and scarlet fever s. pneumonia common cause of pneumonia |
|
|
what is enterococcus?
|
gram positive cocci
catalase negative and come in chains e. faecalis is a normal inhabitant of the colon, but it can be involved in peritonitis |
|
|
what is staphylococcus?
|
gram positive cocci that are catalase positive and come in clusters.
s. aureus can be involved in: acne, toxic shock syndrome, staphylcoccal food poisoning; makes yellow-orange pigmented colonies aureus = gold |
|
|
give an example of listeria
|
listeria monocytogenes
-nonspore forming rod -food borne illness (dairy) -faculative intracellular parasite -capable of direct cell to cell movement - 20-30% mortality rate in symptomatic cases -grows over a wide range of pH and temp. |
|
|
give an example of lactobacillus
|
lactobacillus bulgaricus
-nonsporing forming rod -lactic acid fermentation -used in cheese and yogurt production |
|
|
give an example of streptococcus
|
microaerophilic, catalase negative (unable to break down h2o
streptococcus pyogenes -group A strep -beta hemolytic (complete clearing around colony on blood agar pharyngitis (strep) scarlet fever pyoderma erysipelas necrotizing fascilities |
|
|
give an example of enterococcus
|
natural habitata is in the large intestine
more tolerant to salt and bile salts than streptococcus |
|
|
give an example of staphylococcus?
|
catalase positive (breakdown H2O
staphylococcus aureus -yelloworange pigmented colonies -frequently involved in skin and burn infections, impetego, acne -s. aureus excretes several cytolytic or membrand damaging toxins -staphylococcal scalded skin syndrom -coagulase is an enzyme that causes fibrin to clot, this semms to protect the bacterium from phagocytes -hyalurondidase helps the infection to spread by breaking down hyaluronic acid which helps hold cells and tissues together like sticky glue |
|
|
what are high G + C gram-positive bacteria?
|
corynebacterium
nonspore forming rods, arranged in v-shaped palisades eg. c. diphtheria - infects the throat, excretes a toxin that enters host cells and inactivates the 80S ribosomes, diphtheria is characterized by a gray curtain-like sheet of dead tissue hanging down in the throat |
|
|
what are mycobacterium examples?
|
slow growing, nonspore forming rods, that have waxy mycolic acids in their cell walls (positive in acid-fast stain)
eg. m. tuberculosis causes a chronic lung infection that can spread to the other parts of the body; can grow inside phagolysosomes, that infected cells become surroundedy by lymphocytes and granulocytes leading to the formation of tissue lumps that appear similar to cheese curds use ziehl-neelsen acid-fast stain |
|
|
what are examples of actinomycetes?
|
wide variety of filamentous soil bacteria
many produce antibiotics eg. streptomyces grisues, makes streptomycin streptomycin is an aminoglycoside that inhibits bacterial ribosomes; spores (not endospores) form at the tips of the mature filaments; common scab on potato is caused by streptomycetes |
|
|
what are the differences btw gram positive and gram negative cell wall?
|
gram positive- thick, composed of many layers of peptidoglycan that are bound together by teichoic acids and lipoteichoic acids
gram negative- thinner layer of peptidoglycan; outer membrane with lipopolysaccharides on the outer surface, and a periplasmic space btw the inner and outer membrane |
|
|
gram negative bacteria grouping
|
group 1: spirochetes
group 2: aerobic/microaerophillic, motile, helical/vibroid (azospirillum, bdellovibrio, campylobacter) group3: nonmotile, curved bacteria group4: aerobic/microaerophillic rods and cocci (agrobacterium, azotobacter, azomonas, bordetella, legionella, neisseria, pseudomonas, rhizobium) group5: faculative anearobic rods(enterobacteriaceae, vibrionaceae, pasteurellaceae) group6:anaerobic, straight, curved and helical bacteria(bacteroides) group9: the rickettsias and chlamydias group12: aerobic chemolithotropic bacteria(nitrobacter, nitrosomonas, thiobacillus) |
|
|
gram negative grouping
|
alphaproteobacteria
betaproteobacteria gammaproteobacteria deltaproteobacteria episilonproteobacteria chlamydiae spirochaetes bacteroidetes |
|
|
alphaproteobacteria
|
azospirillum
rhizobium agrobacterium nitrobacter purple nonsulfur bacteria acetobacter and gluconobacter brucella rickettsia |
|
|
betaproteobacteria
|
nitrosomonas
neisseria bordetella burkholeria thiobacillus spirillum |
|
|
gammaproteobacteria
|
purple sulfur bacteria
legionella coxiella methane oxidizers glycolytic facultative anaerobes pseudomonas azotobacter and azomonas |
|
|
deltaproteobacteria
|
desulfovibrio
bdellovibrio myxobacteria |
|
|
episilonproteobacteria
|
campylobacter
helicobacter |
|
|
spirochaetes
|
treponema
borrelia |
|
|
what are bacteria that form symbiotic relationships with plants?
|
azospirillum
rhizobium agrobacterium |
|
|
azospirillum
|
nitrogen fixing association with the roots of tropical grasses including sugar cane
bacteria colonize the surface of grass roots |
|
|
rhizobium
|
forms an endosymbiotic nitrogen fixing association with roots of legumes (peas, beans, clover, alfalfa)
bacteria colonize plant cells within root nodules bacteria converts atmospheric nitrogen to ammonia and then provides organic nitrogenous compounds such as glutamine or ureides to the plant plant provides the bacteria organic compounds made by photosynthesis |
|
|
agrobacterium
|
infects physical wounds of dicotyledenous plants
plasmid DNA is transferred from the bacterium into the plant cells causeing the formation of tumors called crown gall crown gall tumor tissue is modified by bacterial DNA to produce and excrete unusual amino acids called opines that the bacterium uses as food ability to genetically modify plant cells has been used to produce genetically modified crops segement of bacterial plasmid DNA is transferred into a plant cell |
|
|
nitrobacter
|
nitrifying bacterium that helps to convert ammonia to nitrate aerobically (chemolithotrophic metabolism)
ammonia is oxidized to nitrite by nitrosomonas nitrobacter oxidizes the nitrite to nitrate |
|
|
purple nonsulfur bacteria
|
rhodospirillaceae
anoxygenic photosynthesis can use light energy to produce PMF |
|
|
acetobacter and gluconobacter
|
used to make vinegar
incomplete oxidation of ethanol to acetic acid aerobic process, regarded as incomplete respiration |
|
|
brucella
|
brucella abortus
intracellular parasite of endothelial cells infects cattle but can spread to humans mostly causes a mild or assymptomatic disease in cattle but in complicated cases it can cause a cow to loose their unborn calf |
|
|
rickettsia
|
very small obligate intracellular parasites that can absorb ATP from their host cells
are transmitted by arthropods, esp lice ticks r. prowazekii causes typhus r. rikettsii causes rocky mountain spotted tick fever |
|
|
nitrosomes
|
nitrifying bacterium that converts ammonia to nitrite aerobically
|
|
|
neisseria
|
bean shaped diplococci
gram stain results may be misleading as they sometimes appear a bit purple n. gonorrhea = STD n. meningitidis causes meningitis, a severe inflammation of the tissue that covers the spinal cord and brain |
|
|
bordetella
|
b. pertussis causes whooping cough, a respiratory infection that can be very serious in young children
p in dpt vaccination = pertussis |
|
|
pseudomonas
|
respiratory metabolism, they do not ferment glucose anaerobically
many species are involved with rotting plant material p. syringae involved in nucleating ice crystals p. aeruginosa involved in wound and burn infections, produce a blue-green pigment that can lead to blue-pus p. aeruginosa also involved in swimmer's ear |
|
|
azobacter and azomonas
|
form nitrogen fixing symbiosis with plant roots
azotobacter vinelandia forms an association with ash trees |
|
|
glycolytic facultative anaerobes: enterobacteriaceae
|
enterobacteriaceae
entero: intestines many enter. are found in the mammalian large intestine facultative anaerobes that can ferment glucose oxidase negative, catalase postive eg. e. coli, salmonella, enterobacter aerogenes, klebsiella pneumonia, shigella dysenteriae |
|
|
glycolytic facultative anaerobes: vibrionaceae
|
includes:
vibrio cholera (severe diarrhea) vibrio parahaemolyticus (diarrhea) vibrio vulnificus (rapidly progressive wound infections after sea water contact) |
|
|
glycolytic facultative anaerobes: pasteurellaceae
|
includes:
haemophilus influenza (NOT cause of flu)may be involved in cellulitis, pneumonia haemophilus aegyptius (conjunctivitis, pink eye) pasteurella multocida (hemorrhagic septicemia) |
|
|
legionella and coxiella
|
two groups of microo are intracellular parasites
l. pneumophilia causes lung infection c. burnetii cause q fever, respiratory symptoms are mild similar to atypical pneumonia but it can spread to the liver and spleen and develop into acute q fever |
|
|
methane oxidizers
|
live in the aerobic layer of pond sediment that is just above the anaerobic sediments where methanogens live
|
|
|
acid-tolerant gram negative stomack pathogens
|
campybacter- c. jejunii leads to food borne gastroenteritis
helicobacter- h. pylorii involved in formation of gastric ulcers |
|
|
chlamydiae
|
intracellular parasites that are morphologically similar to rickettsia but are transmitted by direct contact rather than by arthropods
c. trachomatis cause std and also eye infectio trachoma c. psittace normally infects birds but can cause an atypical pneumonia in man that is called parrot fever |
|
|
spirochaetes
|
treponema pallidium causes syphillis
borellia burgdorferi is transmitted by ticks and causes lyme disease |
|
|
bacteroidetes
|
obligate anaerobes that make up the majority of normal intestinal microflora, they are present in very high numbers and may be involved in peritonitis if the intestinal wallis perforated
eg. b. fragilis, cause acute peritonitis |
