Micro chapter 11

Pseudomonas

((Aerobic chemoorganotrophs-obligate aerobe) oxidase positive, gram-negative rods, widespread in soils and water, most harmless

Mycobacterium

(Aerobic chemoorganotrophs-obligate aerobe) acid-fast bacteria

Clostridium

(Anaerobic chemoorganotrophs) Gram-positive rods that can form endospores. They ferment a wide variety of compounds, including sugar and cellulose

Purple bacteria

(Anoxygenic phototroph) gram-negative; appear red, orange, or purple due to their light-harvesting pigments; components of photosynthetic apparatus are all contained within the cytoplasmic membrane

Oxygenic phototrophs

Use water as a source of electrons and the biproduct of that is oxygen

Anaerobic chemotrophs

Organisms that harvest energy by oxidizing chemicals. Use carbon dioxide or sulfur as terminal electron acceptors

Methanogens

An example of anaerobic chemolithotrophs. Oxidize H2 gas to generate ATP and use CO2 as terminal electron acceptor. Common in sewage, swamps, digestive tracts

Ammonia oxidizers

Concert ammonia to nitrite

Nitrite oxidizers

Convert nitrite to nitrate

Nitrogen-fixing Cyanobacteria

Critical ecologically; they can incorporate both N2 and CO2 into organic material( so these nutrients can be used by other organisms)

Cyanobacteria

Earliest oxygenic phototrophs; still play essential role as primary producers (harvest sunlight to convert CO2 into organic compounds), gram-negative; diverse group; wide range of environments

Anoxygenic phototrophs

Earliest photo synthesizing organisms. They use hydrogen sulfide or organic compounds (not water) to make NADPH and do not generate O2. Have a different photosystem than plants, algae and Cyanobacteria (use bacteria chlorophyll and absorb wavelengths that penetrate deeper)

Green bacteria

Gram-negative organisms that are typically green or brownish in color; anoxygenic phototrophs

Enterobacteriaceae

Gram-negative rods found in intestinal test of humans and animals: facultative anaerobes that ferment glucose (ex: E.coli) -lactose fermenters called coliforms

Sulfur-oxidizing bacteria

Gram-negative rods, spirals, obtain energy by oxidizing sulfur and reduced sulfur compounds; filmanetous and unicellular lifestyles

Lactic Acid Bacteria

Gram-positive bacteria that produce lactic acid as a major end product of their fermentative metabolism. They lack catalase.

Propionibacterium

Gram-positive irregular shaped rods; produce propionic acid as their primary fermentation end product and can also ferment lactic acid (aka extract energy from a waste product of other bacteria). Important in diary industry: gives cheese the nutty flavor and holes

Heterocysts

Isolate Nitrogenase by confining process of nitrogen fixation to specialized thick-walled cells

Streptococcus

Lactic acid bacteria. Inhabit oral cavity and some are pathogenic

Lactobacillus

Lactic acid bacteria; rod shaped, common in mouth and vagina; present in decomposing materials and important in production of fermented food

Lactococcus

Lactic acid bacteria; used by the dairy industry to produce fermented milk products such as cheese and yogurt

Nitrogenase

The enzyme complex that catalyzes nitrogen fixation is destroyed by O2: therefore nitrogen-fixing Cyanobacteria must protect the enzyme from the O2 they generate

Hydrogen-oxidizing bacteria

Thermophillic: hydrogen (energy source) + oxygen (terminal electron acceptor)= water

Purple non-sulfur bacteria

Use a variety of organic molecules rather than hydrogen sulfide as a source of electrons for reducing power; they lack gas vesicles; they are remarkably versatile metabolically

Nitrifiers

A diverse group of gram-negative bacteria that obtain energy by oxidizing inorganic nitrogen compounds such as ammonia or nitrite; a concern to farmers using ammonium nitrogen; 2 metabolically distinct groups that grow in close association: together they can oxidize ammonia to form nitrate

Obligate aerobe

Obtain energy using respiration exclusively; none can ferment

Aerobic chemoorganotrophs

Oxidize organic compounds for energy (this is what we are): organic compounds (energy source)+oxygen (terminal electro acceptor) =carbon dioxide

Anaerobic chemoorganotrophs

Oxidize organic compounds such as glucose to obtain energy. Often use sulfur or sulfate as a terminal electron acceptor

Aerobic chemolithotrophs

Gain energy by oxidizing reduced inorganic chemicals- use O2 as a terminal electron acceptor: sulfur-oxidizing bacteria

Anaerobic chemolithotrophs

Oxidize reduced inorganic chemicals to obtain energy. Relatively few discovered: methanogens

Facultative anaerobes

Preferentially use aerobic respiration if O2 is available. As an alternative however they can ferment

Purple sulfur bacteria

Relatively large and motile by flagella; most store sulfur in intracellular granules. Use hydrogen sulfide to generate reducing power, but some can use other inorganic molecules (H2) or organic compounds (pyruvate). Many are strict anaerobes and phototrophs but some can grow in the absence of light, oxidize reduced inorganic/organic compounds as a source of energy

Green sulfur bacteria

Similar to purple sulfur bacteria and use hydrogen sulfide as a source of electrons for reducing powers but they form sulfur granules OUTSIDE of the cell; strict anaerobes and none are chemotrophic