Microbiology Chapter 11

What is bioleaching?

A process used to recover metals. Bacteria oxidize insoluble metal sulfides, producing sulfuric acid. This lowers the pH which converts the metal to a soluble form.

Which bacteria produce what chromogens?

spirillum

Obligate aerobes

• Obtain energy using respiration exclusively: none can ferment.

The most medically relevant member of Pseudomonas is P. aeruginosa.

True.

Chemolithotrophs

oxidize reduced inorganic materials such as H2 to obtain energy. They use carbon dioxide or sulfur as terminal electron acceptors.

What is the difference between aerobic and anaerobic chemoorganotrophs?

Anaerobic chemoorganotrophs either undergo respiration (using sulfate as a terminal electron acceptor, producing hydrogen sulfide), or fermentation. Aerobic chemoorganotrophs oxidize organic compounds to obtain energy, using O2 as a terminal electron acceptor.

What is bacteriochlorophyll?

Bacteriochlorophyll is a unique type of chlorophyll found only in anoxygenic phototrophs

What two cellular forms does Chlamydia produce and which one is infectious?

Chlamydia and Chlamydophila. Chlamydia trachomitis causes eye infections and STD's. Chlamydophila causes atypical "walking pneumonia".

Bacteria and Archaea both have members that use sulfur compounds as a terminal electron acceptor.

True

Endospores of Bacillus stearothermophilus are used in testing autoclave operation.

True

Streptomyces produces a number of antibiotics.

True

True or False:The skin and oral cavity may have anaerobic microenvironments.

True

Why is Bifidobacterium important?

Bifidobacterium are found in the intestinal tract of breast-fed infants and are thought to provide a protective function by excluding disease-causing bacteria.

Streptococcus pyogenes causes what disease/diseases?

Streptococcus pyogenes causes strep throat.

What is unusual about Thermus and Deinococcus?

Thermus- they have an unusual cell wall that stains gram-negaitve. They are thermophilic; and this trait has been proven to be extremely valuable because of their heat-stable enzymes which is an integral part of the polymerase chain reaction (PCR). Deinococcus- this species is unique in their extraordinary resistance to the damaging effects of gamma radiation. One type can survive exposure to a dose several thousand times that lethal to a human being. Scienctisits anticipate that through genetic engineering, Deinococcus species may eventually help clean up the soil and water contaminated by the 10 million cubic yards of radioactive waste that have accumulated in the U.S.

What two bacteria genera may form endospores?

Bacillus and Clostridium

What do purple sulfur bacteria and filamentous sulfur-oxidizers both have in common?

They both accumulate sulfur as intracellular granules

What is the stain method used for mycobacterium and nocardia species?

Acid-fast

anoxygenic phototrophs

Live in environments with little to no O2 yet light penetrates. They have a unique type of chlorophyll called bacteriochlorophyll.

Anoxygenic phototrophs grow photosynthetically only under aerobic conditions.

False

What are the characteristic of Lactic Acid Bacteria such as Streptococci?

They are gram-positive bacteria that produce lactic acid as a major end-product.. They ferment but can grow in the presence of O2, and they lack the enzyme catalase.

Which of the following best matches the description?

A.Diarrhea- E.coli B. Tetanus- Clostridium tetani C.Gonorrhea- Neisseira gonorrhea D.Pneumonia- Klebsiella pneumoniae E. Typhoid fever- Salmonella typhi

How is acidithiobacillus important and not important to the environment?

Acidithiobacillus is important in bioleaching and preventing acid rain. It is detrimental by causing runoff that can kill trees, fish, and other wildlife.

What is the difference between aerobic and anaerobic chemolithotrophs?

Anaerobic chemolithotrophs oxidize hydrogen gas using CO2 as a terminal electron acceptor.. Aerobic chemolithotrophs oxidize sulfur compounds as energy sources and use O2 as a terminal electron acceptor.

What organisms produce hydrogen sulfide?

Anaerobic chemoorganotrophs, more specifically, the sulfur- and sulfate- reducing bacteria

Describe the particular biochemical and morphological characteristic of disease-causing Streptococcus species

Cocci that grow in chains of varying lengths. Steptococcus species inhabit the oral cavity as part of the normal microbiota. Some are pathogens like S.pyogenes which causes pharyngitits (strep throat) and other diseases. Unlike the streptococci that inhabit the throat, S. pyogenes is Beta-hemolytic, an important characteristic used to distinguish it from most members of the normal micrsobiota.

The genus of bacteria that is able to fix nitrogen and form heterocysts is?

Cyanobactera

The earliest oxygenic prototrophs are thought to be?

Cyanobacteria

What organism is a primary producer of what by doing what?

Cyanobacteria are primary producers of oxygen by nitrogen-fixing, or breaking down elemental nitrogen.

From chapter 10, what is an evolutionary chronometer?

DNA sequences are viewed as evolutionary chronometers, meaning that sequence differences provide a relative measure of the time elapsed since the organisms diverged from a common ancestor. This is because random mutations cause sequences to change over times. Thus, the more time that has elapsed since two organisms diverged, the greater the differences in the sequences of their DNA.

List the medically important members of the family Enterobacteriaceae

E.coli, Klebsiella pneumoniae, Proteus, Salmonella enterica serotypes Enteritidis and Typhi, Shigella, Yersinia pestis, Haemophilus influenza ad ducreyi, Legionella pneumophila, and Pseudomonas aeruginosa.

What are endospores ad which organisms produce them?

Endospores are heat-resistant dormant forms of bacteria that can only be killed by autoclaving at 132 C for one hour. The organsims that produce them are Bacillus and Clostridium.

Obligate aerobes may transform energy via fermentation.

False

What is Geosmin and what two organisms produce it?

Geosmin is a chemical that produces a distinct "earthy odor" which makes drinking water taste odd. Cyanobacteria and Streptomyces produce geosmin.

What are the characteristics of Propionibacterium?

Gram-positive pleomorphic rods that produce propionic acid as their major end-product. Propionibacterium are responsible for the nutty flavor and holes in swiss cheese caused by CO2.

What does Helicobacter pyloria and Mycoplasma cause?

H. pylori causes duodenal ulcers and stomach cancer, while Mycoplasma is responsbile for causing pneumonia.

Hansen's disease affect what parts of the body?

Hansen's disease affects lower temperature parts of the body such as the extremities, fingertips, nose, ears, toes.

What are the characteristics of Pseudomonas aeruginosa

It is medically the most significant species. It is a common opportunistic pathogen, meaning that it primarily infects people who have underlying medical conditions. Unfortunately, it can grow in nutrient-poor environments, such as water used in respirators, and is resistant to many disinfectants and antimicrobial medications. Because of this, hospitals must be diligent to prevent it from infecting patients

Define anoxygenic photographs and the role they play in the environment.

It is the use of hydrogen sulfide or organic compounds not water as a source of their electrons for reducing power to make NADPH and therefore do not generate oxygen. They have a unique type of chlorophyll called baccteriochlorophyll that absorb wavelengths that penetrates deeper than those for chlorophyll and are not used by other photosynthetic organisms.

Describe Methanogen.

Methanogens are a group of archae that generate ATP by oxidizing hydrogen gas, using CO2 as a terminal electron acceptor. They are highly sensitive to oxygen.

List the two mycobacterium species that cause disease in humans?

Mycobacterium tuberculosis and Mycobacterium leprae.

Organisms that typically produce colonies with a fried egg appearance are called?

Mycoplasma

Complex structures called fruiting bodies are a characteristic of what organism?

Myxobacteria

Which organisms produce what types of dormant structures that allow them to withstand extreme conditions?

Myxobacteria, which produce microcysts, or Bacillus and Clostridium, which produce endospores

It has been estimated that 99% of intestinal bacteria are what?

Obligate anaerobes

Describe purple sulfur and green sulfur bacteria

Purple sulfur • Gram negative Bacteria that can sometimes be seen growing as colored masses in a sulfur-rich aquatic habitats such as sulfur springs. • Use hydrogen sulphide to generate reducing power, although some species can use other inorganic molecules such as hydrogen or organic compounds (pyruvate) • Many are strict anaerobes and photographs' but some can grow in absence of light aerobically, oxidizing reduced inorganic or organic compounds as a source of energy. • The cells are relatively large (5um in diameter), and some are motile by flagella • May have gas vesicles that enable them to move to their preferred level in water column. • Most accumulate sulfur in granules and appear to be contained within the cell • Representative genera of purple sulfur bacteria include chromatium, thiospirillum and thiodictyon Green Bacteria • gram negative organisms that are found in similar habitats to the purple bacteria • use hydrogen sulfide as a source of electrons for reducing power and form sulfur granules (but the granules form outside of the cell) • the accessory pigments of the green sulphur bacteria are located in structures called chlorosomes • NO flagella but have gas vesicles • All are strict anaerobes and none can be use a chemotrophic metabolism • Representative genera include chlorobim and pelodictyon.

Which organisms are obligate intracellular parasites?

Rickettsia, Orientia, Ehrlichia, Coxiella, Chlamydia, and Wolbachia.

Clostridium, Lactobacillus, and Propionibacterium all have what in common?

They are all gram positive rods ,anaerobes that grow in the absence of oxygen, involved with fermentation. They oxidize organic compounds and use organic compounds as terminal electron acceptors. • Members of the genus clostridium are gram positive rods that can form endospores. They are common inhabitants of the soil where their vegetative cells live in the anaerobic micro environment created when the aerobic organisms consume available oxygen. A group of clostridium species ferment a wide variety of compounds including sugars and cellulose. • Members of the lactobacillus are rod shaped bacteria. Like the lactococci they are important in the production of fermented foods • Propionicbacteria species are gram positive pleomorphic rods that produce propionic acid as their primary fermentation end product. Species are important to the dairy industry because their end products play an indispensable role in the production of Swiss cheese. Propionic bacterium species are also found in the intestinal tract and in anaerobic microenvironment on the skin.

What are heterocysts and what are they used for?

They are special, thick-walled cells that protect nitrogenase (the enzyme that works in nitrogen-fixing) from O2, which destroys it.

Describe the role of Lactobacilli as normal flora in the vagina.

They break down glycogen in the vaginal lining in response to estrogen. This lowers the pH of the vagina, providing an acidic environment where bacteria cannot grow.

Chemoorganotrophs

They can be either undergo respiration or fermentation. Those that undergo respiration oxidize organic compounds such as glucose to obtain energy and use either sulfur or sulfate as terminal electron acceptors. Those that undergo fermentation, and can only obtain energy by fermentation.

What is the significant role of sulfur oxidizers to the environment?

They obtain energy by oxidizing elemental sulfur and reduced sulfur compounds. O2 is their terminal electron acceptor, which generates sulfuric acid. These bacteria are important in the sulfur cycle.

Chlamydia occurs in two forms, a reticulate body and an elementary body.

True

What disease does Treponema and Borrelia cause?

Treponema causes Syphillis, while borrelia causes Lyme disease and relapsing fevers.

What are trichomes?

Trichomes are filamentous cellular associations that may or may not be enclosed within a sheath (a tube that holds and surrounds a chain of cells). Motile trichomes glide as a unit.