Microbiology Chp 11
The Green Bacteria
- Anoxygenic Phototrophs - Green Sulfur Bacteria (use hydrogen sulfide as a source of e-, granules form outside of the cell, chlorosomes accessory pigment, no flagella, may have vesicles. - Filamentous Anoxygenic Phototrophic Bacteria (multicellular arrangements, exhibit gliding motility, may have chlorosomes
The Hydrogen-Oxidizing Bacteria
- Aquifex and Hydrogenobacter species are thermophilic bacteria and thought to be among the earliest bacterial forms to exist on earth.
Extreme Halophiles
- Archaea - found in salt lakes, soda lakes, and brines used for curing fish
Bacteria That Associate with Plants
- Agrobacterium species cause plant tumors. - Rhizobia reside as endosymbionts in nodules formed on the roots of legumes, fix N2
Methanogens
- Anaerobic Chemolithotrophs - are a group of archaea that generate ATP by oxidizing hydrogen gas, using CO2 as a terminal electron acceptor. - include Methanospirillum and Methanosarcina - found in anaerobic environments where hydrogen gas and carbon dioxide are available. - sensitive to O2
The Lactic Acid Bacteria
- Anaerobic Chemoorganotrophs that uses fermentation - Gram + bacteria that produce lactic acid as a major end product - include Streptococcus, Enterococcus, Lactococcus, Lactobacillus, and Leuconostoc - obligate fermenters (no O2 benefit) - Most can grow in aerobic environments
The Genus Propionibacterium
- Anaerobic Chemoorganotrophs that uses fermentation - Gram-positive pleomorphic (irregular- shaped) rods that produce propionic acid - can also ferment lactic acid (the waste of Lactic acid bacteria) - important to the dairy industry in the production of Swiss cheese - also grows in the intestinal tract & in anaerobic microenvironments on the skin
The Genus Propionibacterium
- Anaerobic Chemoorganotrophs that uses fermentation - Gram-positive rods that can form endospores - common inhabitants of soil - endospores indifferent to O2, survive long periods of heat, desiccation, chemicals, and irradiation - causes tetanus (C. tetani), gas gangrene (C. perfringens), and botulism (C. botulinum) - ferment a wide variety of compounds, including sugars and cellulose - includes normal inhabitants of the intestinal tract - C. acetobutylicum produces acetone and butanol
Sulfur- and Sulfate-Reducing Bacteria
- Anaerobic Chemoorganotrophs—Anaerobic Respiration - reduces sulfur (the terminal electron acceptors) to form hydrogen sulfide - H2S is a problem to industry because it reacts with metals - generally live in mud rich in organic material - includes Desulfovibrio (Gram-negative curved rod shaped) - mesophiles or thermophiles bacteris - hyperthermophiles archaea
Bacteria That Form a Resting Stage
- Bacillus and Clostridium form endospores - Azotobacter form a cyst, fix N2 in aerobic conditions - Myxobacteria form a fruiting body - Streptomyces form chains of conidia at the end of hyphae
The Purple Bacteria
- Anoxygenic Phototrophs - Gram-negative organisms that appear red, orange, or purple due to their light-harvesting pigments - includes Purple Sulfur Bacteria (use H2S, has gas vesicles, flagellated, accumulate sulfur granules) - Purple Non-Sulfur Bacteria (use organic molecules, no gas vesicles)
Name two genera of endospore-forming bacteria. How do they differ?
Bacillus and Clostridium
What kind of bacteria might compose the subsurface scum of polluted ponds?
Cyanobacteria
What characteristics of Azotobacter species protects their nitrogenase enzyme from inactivation by O2?
Due to high respiration rate anaerobic environment is maintained in the cell
Give three examples of energy sources used by chemolithotrophs.
H2, CO2, Lactic Acid
What unique motility structure characterizes the spirochetes?
axial filament.
Which of the following genera fix nitrogen? 1. Anabaena 2. Azotobacter 3. Deinococcus 4. Mycoplasma 5. Rhizobium a) 1, 3, 4 b) 1, 2, 5 c) 2, 3, 5 d) 2, 4, 5 e) 3, 4, 5
b) 1, 2, 5
The dormant forms of which of the following genera are the most resistant to environmental extremes? 1. Azotobacter 2. Bacillus 3. Clostridium 4. Myxobacteria 5. Streptomyces a) 1, 2 b) 2, 3 c) 3, 4 d) 4, 5 e) 1, 5
b) 2, 3
All of the following genera are spirochetes, except a) Borrelia b) Caulobacter c) Leptospira d) Spirochaeta e) Treponema
b) Caulobacter
Which of the following archaea would most likely be found coexisting with bacteria? a) Nanoarchaeum b) Halobacterium c) Methanococcus d) Picrophilus e) Sulfolobus
c) Methanococcus
Serological tests involving which structures help distinguish the different enterobacteria from each other?
cell walls, flagella, and capsules
Members of which of the following genera are coliforms? a) Bacteroides b) Bifidobacterium c) Clostridium d) Escherichia e) Streptococcus
d) Escherichia
All of the following genera are obligate intracellular parasites, except a) Chlamydia b) Coxiella c) Ehrlichia d) Mycoplasma e) Rickettsia
d) Mycoplasma
Thermoplasma and Picrophilus grow best in which of the following extreme conditions? a) Low pH b) High salt c) High temperature d) a and c e) b and c
d) a and c
Which of the following genera would you most likely find growing in acidic runoff from a coal mine? a) Clostridium b) Escherichia c) Lactic acid bacteria d) Thermus e) Acidithiobacillus
e) Acidithiobacillus
A catalase-negative colony growing on a plate that was incubated aerobically could be which of these genera? a) Bacillus b) Escherichia c) Micrococcus d)Staphylococcus e) Streptococcus
e) Streptococcus
Bacteria That Inhabit Mucous Membranes
- Bacteroides species inhabit mouth, intestinal tract, genital tract - Bifidobacterium species reside primarily in the intestinal tract - Campylobacter and Helicobacter species are microaerophilic - Haemophilus species found in blood - Neisseria species in the oral cavity and genital tract, nutritionally fastidious, obligate aerobes - Treponema and Borrelia - spirochetes, inhabit mucous membranes
Bacteria That Derive Nutrients from Other Organisms
- Bdellovibrio species prey on other bacteria - Epulopiscium species reside within the intestinal tract of surgeon fish -Legionella species often reside within protozoa and can cause respiratory disease
The Sulfur-Oxidizing Bacteria
- Beggiatoa and Thiothrix - live in sulfur springs, sewage-polluted waters, surface of marine and freshwater sediments - Acidithiobacillus species found in terrestrial and aquatic habitats.
Prosthecate Bacteria
- Caulobacter species have a single polar prostheca called a stalk; at the tip of the stalk is a holdfast. divide by binarry fission - Hyphomicrobium species divide by forming a bud at the tip of their single polar prostheca
Facultative Anaerobes
- Corynebacterium - inhabit soil, water, and the surface of plants - Enterobacteriaceae - inhabit the intestinal tract of animals, soil -
Extreme Thermophiles
- Methanothermus species - hyperthermophiles that generate methane - Nanoarchaea grow as spheres attached to Ignicoccus species -
Obligate Aerobes
- Micrococcus - found in soil, dust particles, inanimate objects, skin - Mycobacterium species are widespread, acid fast - Pseudomonas - widespread in nature, have extremely diverse metabolic capabilities - Thermus aquaticus is the source of Taq polymerase - Deinococcus radiodurans can survive high gamma radiation
The Nitrifiers
- Nitrosomonas and Nitrosococcus (ammonia oxidizers) convert ammonia to nitrite - Nitrobacter and Nitrococcus (nitrite oxidizers) convert nitrite to nitrate
Aerobic Chemoorganotrophs
- Obligate Aerobes - Facultative Anaerobes
The Cyanobacteria
- Oxygenic Phototrophs - convert CO2 into organic compounds using sunlight - primary producers, gram -, N2 fixation - have chlorophyll and phycobiliproteins
Obligate Intracellular Parasites
- Rickettsia, Orientia, and Ehrlichia are spread by vectors - Chlamydia & Chlamydophila transmitted directly from person to person - Wolbachia pipientis alters the reproductive biology of infected arthropods -
Bacteria that Thrive in Aquatic Environments
- Sheathed Bacteria - Prosthecate Bacteria - Bacteria That Derive Nutrients from Other Organisms - Bacteria That Move by Unusual Mechanisms - Bacteria That Form Storage Granules
Bacteria That Form Storage Granules
- Spirillum volutans forms polyphosphate granules - Thiomargarita namibiensis - largest known bacterium, stores granules of sulfur and has a nitrate-containing vacuole.
Bacteria That Move by Unusual Mechanisms
- Spirochetes move by means of an axial filament - Magnetotactic bacteria contain a string of magnetic crystals that enable them to move
Bacteria That Inhabit the Skin
- Staphylococcus (facultative anaerobes)
Aerobic Chemolithotrophs
- The Sulfur-Oxidizing Bacteria - The Nitrifiers - The Hydrogen-Oxidizing Bacteria
Oxygenic Phototrophs
- cyanobacteria - The Sulfur-Oxidizing Bacteria
Anoxygenic Phototrophs
- earliest photosynthesizing organisms - se hydrogen sulfide or organic compounds rather than water for e- - have unique bacteriochlorophyll but do not generate O2 - The Purple Bacteria - The Green Bacteria - Heliobacterium
Sheathed Bacteria
- form chains of cells encased in a sheath, which enables cells to attach to solid objects in favorable habitats while sheltering them from attack by predators
Anaerobic Chemoorganotrophs—Fermentation
- obtain energy by fermentation, producing ATP only by substrate-level phosphorylation - The Genus Colostrum - The Lactic Acid Bacteria - The Genus Propionibacterium
Anaerobic Chemoorganotrophs—Anaerobic Respiration
- oxidize organic compounds such as glucose to obtain energy - Those that grow anaerobically often employ sulfur or sulfate as a terminal electron acceptor
Anaerobic Chemolithotrophs
- oxidize reduced inorganic chemicals such as hydrogen gas (H2) to obtain energy - most are members of the Domain Archaea
Compare and contrast the relationships of Agrobacterium and Rhizobium species with plants.
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What kind of bacterium might be responsible for plugging the pipes in a sewage treatment facility?
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Anaerobic Chemotrophs
Anaerobic Chemolithotrophs Anaerobic Chemoorganotrophs—Anaerobic Respiration Anaerobic Chemoorganotrophs—Fermentation
In what way does the metabolism of Streptococcus species differ from that of Staphylococcus species?
Staphylococcus species are catalase positive. This distinguishes them from Streptococcus, Enterococcus, and Lactococcus species, which are also Gram + cocci but lack the enzyme catalase.
How have species of Streptomyces contributed to the treatment of infectious diseases?
Streptomyces species naturally produce a wide array of medically useful antibiotics, including streptomycin, tetracycline, and erythromycin.
Which of the following genera preys on other bacteria? a) Bdellovibrio b) Caulobacter c) Hyphomicrobium d) Photobacterium e) Sphaerotilus
a) Bdellovibrio
