ch11

The species ______ has been linked to gastric ulcers in humans.

Helicobacter pylori The -(epsilon) Proteobacteria

Why do many gastric-ulcer patients respond favorably to treatment with antibiotics?

If antibacterial drugs lead to improvement, the assumption is that some gastric ulcers must be caused by stomach bacteria sensitive to the antibiotic. Do you recall if there is such a bacterium?

Members of the genus ______are common in soil and water. Many fix nitrogen from the air. Klebsiella pneumoniae causes pneumonia in humans.

Klebsiella

______species and other sulfur-oxidizing bacteria are parts of the important sulfur cycle . These chemoautotrophic bacteria oxidize reduced forms of sulfur, such as hydrogen sulfide (H2S) or elemental sulfur (S0 ) into sulfates (SO4 2-).

Thiobacillus The -(beta) Proteobacteria

The ______species are the cause of the disease brucellosis in mammals. They are able to survive phagocytosis by the host's defenses.

Brucella (The -(alpha) Proteobacteria )

These gram-positive rod-shaped bacteria, aerobic or facultatively anaerobic, are distinguished by possession of endospores. ______ is the cause of anthrax in humans and animals; ______is an insect pathogen; ______is an occasional cause of food poisoning.

Bacillus anthracis, Bacillus thuringiensis , Bacillus cereus

The genus ______is a member of a group of anaerobic, gram-negative bacteria that live in the human intestinal tract in huge numbers. Infections by Bacteroides bacteria often result from wounds or surgery.

Bacteroides

The genus _____contains several members that are human pathogens. This includes Bartonella henselae, the cause of cat-scratch disease.

Bartonella (The -(alpha) Proteobacteria )

The only species is_____, which morphologically resembles cyanobacteria but is not photosynthetic. It uses hydrogen sulfide as an energy source.

Beggiatoa alba The -(gamma) Proteobacteria

The cause of pertussis, or whooping cough, is ____

Bordetella pertussis The -(beta) Proteobacteria

______means that the G + C ratio is on the order of, as an example, that of the genus Streptococcus, whose ratio is 33-44%.

A low G + C positive bacteria ratio

The genera ______ are industrially important aerobic bacteria that convert ethanol into acetic acid (vinegar).

Acetobacter and Gluconobacter (The -(alpha) Proteobacteria )

The genus ______was formerly classified with the genus Pseudomonas. These are aerobic, gram-negative rods that are motile with a single polar flagellum or tuft of flagella. Nutritionally, they are capable of degrading a wide spectrum of organic molecules.

Burkholderia The -(beta) Proteobacteria

_______ causes spontaneous abortion in domestic animals; Campylobacter jejuni causes foodborne intestinal disease.

Campylobacter fetus The -(epsilon) Proteobacteria

Both ______ produce prominent prosthecae, a term applied to protrusions such as stalks or buds. Caulobacteria are found in aquatic environments such as lakes. They feature stalks that anchor them to surfaces. This increases their nutrient uptake in these low-nutrient environments. ______reproduction results in one stalked cell and one flagellated swarmer cell, which eventually becomes another stalked cell. _______bacteria, which divide by budding, increase in size until separating into new cells, and are found in low-nutrient waters.

Caulobacter and Hyphomicrobium, Caulobacter, Hyphomicrobium (The -(alpha) Proteobacteria )

Treponema, Borrelia, Leptospira______. The spirochetes have a coiled morphology and are motile by means of axial filaments (endoflagella). _____, attached at the end of the cell, are wound around the body of the cell in the space between an outer sheath and the body of the cell. The cell moves by stretching and relaxing the axial filaments. Treponema pallidum, the cause of syphilis; the genus Borrelia, which causes relapsing fever and Lyme disease; and Leptospira species, which cause leptospirosis, are all spirochetes.

commonly called spirochetes, Axial filaments

The ______tend to be pleomorphic. The best-known species is Corynebacterium diphtheriae, the cause of diphtheria.

corynebacteria

The _______are photosynthetic aerobes that carry out oxygen-producing photosynthesis much like higher plants. Many species of cyanobacteria are capable of fixing nitrogen from the atmosphere. For this they use enzymes carried in structures called ________. They are morphologically varied; unicellular and filamentous forms are common.

cyanobacteria , heterocysts

1. Bdellovibrio. 2. Helicobacter. 3. Pseudomonas. 4. Escherichia. 5. Rhizobium. 6. Neisseria.

d. Delta proteobacteria e. Epsilon proteobacteria c. Gamma proteobacteria c. Gamma proteobacteria a. Alpha proteobacteria b. Beta proteobacteria

Usually, nutrients are assimilated during metabolism; when they are not assimilated and external products such as hydrogen sulfide gas are formed, this is termed______metabolism.

dissimilatory

1. Serovars, typhoid fever. 2. Cause of Q fever. 3. Several Pseudomonas species have been reclassified into this genus. 4. Grow obligately in white blood cells; cause a tickborne disease. 5. Endosymbionts of insects.

e. Salmonella c. Coxiella a. Burkholderia b. Ehrlichia d. Wolbachia

The genus Rhizobium is important for agriculture because it allows ____plants such as peas to fix nitrogen.

leguminous

A gram-positive bacterium with a G + C content of 35% would be considered a member of the ______G + C gram-positive bacteria.

low

Appendages such as stalks or buds on bacteria are called_____

prosthecae

The _____, which include most of the gram-negative, chemoheterotrophic bacteria, are presumed to have arisen from a common photosynthetic ancestor. Few are now photosynthetic

proteobacteria

This physiological group is taxonomically confusing: There are purple sulfur bacteria and purple nonsulfur bacteria and green sulfur bacteria and green nonsulfur bacteria. The important _____ bacteria are -proteobacteria. The _____bacteria are -proteobacteria. The ______ bacteria are nonproteobacteria. For simplicity we group them all here. These are photosynthetic bacteria, which, unlike plants, do not produce oxygen (are anoxygenic), and are generally anaerobic. Their habitat is deep aquatic sediments. _____is an important genus.

purple sulfur, purple nonsulfur , green sulfur and green nonsulfur, Chromatium

Serratia marcescens colonies produce a______-colored pigment.

red

The _____, gram-positive cocci that typically appear in chains, are metabolically similar to the lactobacilli. _____bacteria cause a great variety of diseases. _____ species form a greenish zone around a colony on blood agar. _____ species form a clear zone of hemolysis. This hemolytic group includes Streptococcus pyogenes, which is the principal streptococcal pathogen. It causes scarlet fever, pharyngitis (sore throat), erysipelas, impetigo, and rheumatic fever. _______ streptococci are nonhemolytic. Streptococcal pathogens also include Streptococcus pneumoniae, the most common cause of human pneumonia, and Streptococcus mutans, the cause of dental caries (cavities).

streptococci, Streptococcus , Alpha-hemolytic, Beta-hemolytic, Gamma-hemolytic

The term ______is applied to helical bacteria that do not complete a full turn morphologically.

vibrioid

The genera _______ are heavily capsulated aerobes that fix nitrogen from the atmosphere.

Azotobacter and Azomonas

_______species are the cause of the respiratory disease legionellosis.

Legionella

______ produces a distinctive red pigment and occasionally causes infections of the urinary and respiratory tracts in hospital patients.

Serratia marcescens

1. Endospores. 2. Anaerobic, gram-negative, slender rods with pointed ends. 3. Filamentous bacteria that produce most of our commercial antibiotics. 4. Gram-positive cocci that form grapelike clusters. 5. Gram-positive cocci that are aerotolerant anaerobes. 6. Cause of cat-scratch disease.

a. Clostridium e. Fusobacterium d. Streptomyces c. Staphylococcus d. Streptomyces f. Bartonella

1. Many of these are plant pathogens, causing plant soft-rot diseases. 2. Infectious by elementary bodies. 3. Filamentous bacteria, aerobes; cell wall resembles mycobacteria; often stain acid-fast. 4. Spirochetes. 5. Some of these are stalked and attach themselves to aquatic surfaces. 6. Many are capable of fixing nitrogen from air.

a. Erwinia f. Chlamydia d. Nocardia c. Leptospira b. Caulobacter e. Klebsiella

Streptococcus pyogenes is an example of _____-hemolytic bacteria.

beta

These bacteria are filamentous and often resemble molds by using externally carried asexual spores for reproduction. One genus, Frankia, causes formation of nitrogen-fixing nodules on alder tree roots. Streptomyces form conidiospores at the ends of filaments. Strict aerobes, these bacteria are important degraders of proteins, starch, and cellulose in soil. They produce ______, a gas that gives soil its odor. Most commercial antibiotics are produced by Streptomyces. The genus Actinomyces consists of facultative anaerobes found in the mouth and throat of humans and animals. These bacteria occasionally form filaments that can fragment for reproduction. Actinomyces israelii causes actinomycosis. Nocardia morphologically resemble Actinomyces; however, they are aerobic. Their cell wall resembles the mycobacteria and they are often acid-fast. Nocardia asteroides is an occasional cause of pulmonary infections or mycetoma (tissue destruction) of the hands or feet.

geosmin

The _____are aerobic rods that stain acid-fast. This staining characteristic is related to their cell wall, in which the outer lipopolysaccharide layer of most gram-negative bacteria is replaced by mycolic acids. This makes it difficult for stains, nutrients, and antimicrobials to enter the cell, but makes them relatively resistant to environmental stresses. Important pathogens are Mycobacterium tuberculosis, the cause of tuberculosis, and Mycobacterium leprae, the cause of leprosy.

mycobacteria

Members of the _____move by gliding and leave a slime trail. For nutrition they ingest and lyse bacteria. In their life cycle large numbers of vegetative cells converge on a single point, where they aggregate and differentiate into a stalked body that carries resting cells called myxospores. These myxospores eventually germinate and renew the cycle.

myxobacteria

This is a genus of small, pleomorphic bacteria that includes the cause of tularemia, _______

Francisella tularensis The -(gamma) Proteobacteria

Another genus of gram-negative anaerobic bacteria is ______. These slender microbes have pointed rather than blunt ends. They are found in the gingival crevices of the gums and may cause some abscesses.

Fusobacterium

______is the best-studied genus of the sulfur-reducing -proteobacteria. It is found in anaerobic sediments and in the intestinal tracts of mammals. It uses hydrogen sulfide as part of photosynthesis or as an energy source. Because the H2S is not assimilated as a nutrient, this type of metabolism is termed dissimilatory.

Desulfovibrio

The ______are motile by gliding over surfaces and are important cellulose degraders in soil

Cytophaga

Which morphological type of bacteria would be the most efficient in taking up nutrients, given that they have the same volume, a spherical cell or a filamentous cell? Briefly explain your answer.

All things being equal, the ratio of surface area to volume is critical in determining the uptake of nutrients. A sphere has the smallest surface area for a given volume. Filamentous shapes generally have a much larger surface area for a given volume and take up nutrients more efficiently. However, the spherical shape is stronger for resistance to environmental stresses.

______is a predator on other bacteria, reproducing within gram-negative bacteria, which it kills.

Bdellovibrio The -(delta) Proteobacteria

This group of organisms includes the extreme halophiles such as Halobacterium or Halococcus that require high concentrations of sodium chloride to grow. Sulfolobus also thrives in extreme environments such as acidic, sulfur-rich hot springs. The methane-producing bacteria, Methanobacterium, which derive their energy by combining hydrogen (H2) with CO2 to form methane (CH4), are important in anaerobic sewage treatment. The archaea are grouped by related ribosomal RNA sequences; their cell walls lack peptidoglycan.

Domain Archaea

Urinary tract infections and hospital-acquired infections are often caused by ______

Enterobacter cloacae and Enterobacter aerogenes.

_______lacunata is considered a cause of conjunctivitis, an eye infection

Moraxella

Members of the genus _____are aerobic, gram-negative cocci that include Neisseria gonorrhoeae, which causes gonorrhea, and Neisseria meningitidis, which causes meningococcal meningitis.

Neisseria The -(beta) Proteobacteria

The genus _____infects roots of leguminous plants such as peas, beans, or clover. This causes formation of nodules, within which the bacteria symbiotically fix nitrogen for the plant. ______ also infects plants. It introduces bacterial DNA in a plasmid that results in a disease called crown gall. This bacterium's plasmid is also used in genetic engineering of plants to introduce foreign DNA.

Rhizobium , Agrobacterium tumefaciens (The -(alpha) Proteobacteria )

______are microaerophiles. Morphologically they are vibrioids—a term applied to helical bacteria that do not have a complete turn.

The campylobacteria The -(epsilon) Proteobacteria

______ are adapted to areas rich in nutrients but low in oxygen, such as the gastrointestinal tract, vagina, and oral cavity. They have high resistance to antibiotics and are a cause of nosocomial infections, entering the bloodstream through indwelling catheters, surgical wounds, etc.

The enterococci (Enterococcus faecalis and E. faecium especially)

What characteristics do you think would favor the proliferation of a bacterial species a. in the human intestinal tract? b. on a rock of newly cooled liquid lava that is just protruding above the sea?

a. Conditions in the human intestinal tract would be rich in preformed organic nutrients, so little synthesizing from simple compounds such as carbon dioxide would be required. Environmental stresses such as low moisture or radiation would be low, so cellular resistance to such stresses would be minimal. Oxygen would be limited, so strictly aerobic bacteria would not thrive. b. On newly cooled rock there would be minimal amounts of nutrients. The ability to obtain energy from sunlight would be very advantageous. Among the nutrients that would be especially limited would be carbon and nitrogen. A bacterium that used carbon dioxide from the atmosphere and could extract nitrogen from the atmosphere would outgrow bacteria that had to obtain carbon and nitrogen from organic material. Nitrogen-fixing strains of cyanobacteria should come to mind.

1. Found in some nitrogen-fixing Cyanobacteria. 2. Found in cell wall of Mycobacterium. 3. Provide motility to spirochetes. 4. Produced by many Streptomyces.

a. Heterocysts d. Mycolic acids b. Endoflagella e. Geosmin

_____-hemolytic types of bacteria form a narrow, greenish zone of hemolysis on blood agar plates.

alpha

The _______ are gram-negative, rickettsialike bacteria that live obligately within white blood cells. They cause the tickborne disease ehrlichiosis.

ehrlichiae (The -(alpha) Proteobacteria )

The cell walls of the archaea do not contain_____

peplidoglican

Bergey's Manual of Systematic Bacteriology is the standard reference for bacterial taxonomy. At this time a second edition, based upon a phylogenetic system, is replacing the phenotypic system based upon morphologic characteristics. The new phylogenetic system is based mostly on differences in ribosomal RNA (rRNA). Ribosomal RNA is slow to change and performs the same functions in all microbes. Comparisons of DNA are sometimes useful at the species and genus level. In the second edition of Bergey's Manual the prokaryotes are grouped into two domains, ______. Both domains are bacteria in the sense that they are prokaryotic cells. Eukaryotic multicellular and unicellular organisms are in the domain ______.

the Archaea and the Bacteria (formerly Eubacteria), Eukarya

______is a soil bacterium that grows in close association with roots, especially of tropical grasses. They use excreted nutrients and aid plant growth by fixation of atmospheric nitrogen.

Azospirillum (The -(alpha) Proteobacteria )

Members of the genus ____are obligately anaerobic rod-shaped cells containing endospores that usually distend the cells. Clostridium botulinum causes botulism, Clostridium tetani causes tetanus, and Clostridium perfringens causes gas gangrene. Clostridium difficile is an inhabitant of the intestinal tract that may cause serious diarrhea when antibiotic therapy alters the normal intestinal flora.

Clostridium

_______ resembles the rickettsias, requiring a mammalian host cell to reproduce. It is the cause of Q fever, which is transmitted to cattle by ticks and to humans by contact or aerosols.

Coxiella burnetii

The bacterium ______fishelsoni is extraordinarily large, over half a millimeter in length. It does not reproduce by binary fission. Daughter cells formed within the cell are released through a slit opening in the parent cell—a process possibly related to the evolutionary development of sporulation.

Epulopiscium

_____ species are primarily plant pathogens, causing soft-rot diseases by hydrolyzing the pectin between plant cells.

Erwinia

_____ is one of the most common inhabitants of the human intestinal tract and a familiar laboratory bacterium. It is used as an indicator organism for fecal pollution. It can cause urinary tract infections. Occasionally, enterotoxins produced by E. coli cause traveler's diarrhea and even, in the case of E. coli O157:H7, very serious foodborne disease.

Escherichia coli

Assuming that both types of bacteria were present on the Earth before other life arose, which photosynthesizing bacterium would have been the most valuable to support other life when it appeared, cyanobacteria or purple sulfur bacteria?

First, the cyanobacteria produce oxygen as they photosynthesize--a factor essential to mammalian life as we know it. Second, many cyanobacteria fix nitrogen, which would be valuable.

_____ is one of the most common forms of vaginitis. Highly pleomorphic and gram-variable, its taxonomic position has always been uncertain.

Gardnerella vaginalis

________ is a common cause of meningitis, earaches, and a number of other important diseases. Haemophilus bacteria are cultured on media enriched by hemoglobin or culture media containing X factors and V factors. Haemophilus ducreyi is the cause of the sexually transmitted disease chancroid.

Haemophilus influenzae

These gram-positive bacteria lack a cytochrome system and are unable to use oxygen as an electron acceptor. They are aerotolerant, however, and grow in the presence of oxygen. The genus ______is found in the vagina, intestinal tract, and oral cavity. Industrially, they are used in production of sauerkraut, pickles, buttermilk, and yogurt.

Lactobacillus

_____monocytogenes survives within phagocytic cells, can grow at refrigerator temperatures, and can cause serious damage to a fetus.

Listeria

A single gram of soil may contain 10,000 or so bacterial types—about twice as many as have ever been described. Illustrating such diversity, recently in coastal waters off Africa another example of a giant bacterium, Thiomargarita namibiensis, has been discovered. It is a fluid-filled sphere that in this way minimizes nutrient absorption problems. It obtains its energy mainly from oxidation of hydrogen sulfide.

Microbial Diversity

These are agriculturally important chemoautotrophs. ____ species oxidize ammonium (NH4 + ) to nitrite (NO2 - ), which is in turn oxidized by _______species to nitrates (NO3 - ). The process is called nitrification. (Nitrosomonas is discussed here for convenience, but is actually a member of the -proteobacteria.)

Nitrobacter, Nitrosomonas (The -(alpha) Proteobacteria )

These are nonmotile bacteria primarily causing diseases in domestic animals. _____ is transmitted to humans by animal bites.

Pasteurella multocida

Some species of this genus, which produces propionic acid, are used in the fermentation of Swiss cheese. ______ is a skin bacterium implicated as the primary bacterial cause of acne.

Propionibacterium acnes

Colonies of ______growing on agar show a swarming type of growth with the appearance of concentric rings. They are responsible for many urinary tract and wound infections.

Proteus

The genus _______characterized by one of several polar flagella. Many species excrete extracellular, water-soluble pigments. Pseudomonas aeruginosa produces a blue-green pigment and can infect the urinary tract, burns, and wounds. Pseudomonads are common in soil and can often grow at refrigerator temperatures. They are able to decompose chemicals such as pesticides in soil, and their ability to grow in antiseptic solutions and whirlpool baths, as well as their resistance to antibiotics, make them troublesome. Many pseudomonads substitute nitrate for oxygen during anaerobic respiration, depleting nitrate fertilizers, which escape as nitrogen gas. Pseudomonas syringaeis a plant pathogen.

Pseudomonasis

_______are gram-negative, obligately intracellular parasites, frequently pathogenic; they are responsible for diseases known as the spotted fever group. They are often transmitted to humans by bites of insects or ticks. Among rickettsial diseases are epidemic typhus caused by Rickettsia prowazekii (louseborne), endemic murine typhus caused by Rickettsia typhi (rat-flea-borne), and Rocky Mountain spotted fever caused by Rickettsia rickettsii (tickborne).

Rickettsias (The -(alpha) Proteobacteria )

Almost all members of the genus _____are pathogenic. Typhoid fever is caused by Salmonella typhi; most cause a less serious gastrointestinal disease called salmonellosis. Taxonomically, the salmonellae are divided into about 2300 _____ by serological means; serovars are further differentiated by biochemical, physiological properties into biovars (or biotypes). For most purposes all are considered a single species, Salmonella enterica. Many are known by antigenic formulas according to the Kauffman-White scheme. For example, Salmonella typhimurium (more properly written as Salmonella enterica serovar Typhimurium) is represented as O-antigens 1, 4, (5), 12 H-antigens i, 1, 2. S. bongori is a second species but is not a human pathogen.

Salmonella , serovars (or serotypes)

Species of ____cause bacillary dysentery, or shigellosis, and are responsible for many cases of traveler's diarrhea. They infect only humans.

Shigella

Sheathed bacteria, including ______, are found in sewage and fresh water. These gram-negative bacteria with polar flagella form a hollow, filamentous sheath in which to live.

Sphaerotilus natans The -(beta) Proteobacteria

These are helical bacteria that are motile by conventional polar flagella. Species such as ______ are relatively large, gram-negative, aerobic bacteria whose habitat is fresh water.

Spirillum volutans The -(beta) Proteobacteria

______are gram-positive cocci that occur in grapelike clusters. The most important species is Staphylococcus aureus. Staphylococci are able to survive and grow at high osmotic pressures. S. aureus produces a yellow pigment and many toxins, including an enterotoxin that causes food poisoning.

Staphylococci

Members of the phylum Chlamydiae are grouped with other genetically similar bacteria that do not contain peptidoglycan in the cell walls. ________, which are gram-negative bacteria, have a unique developmental cycle that is illustrated in Figure 11.22 in the text. It requires a host mammalian cell. The elementary body attaches to a host cell, enters, and is housed in a cell vacuole. There the elementary body becomes a reticulate body that divides successively. Eventually, these condense into infectious elementary bodies that are released to infect surrounding host cells. Chlamydia trachomatis causes trachoma, as well as the sexually transmitted diseases nongonococcal urethritis and lymphogranuloma venereum. Chlamydia psittaci causes psittacosis (ornithosis). Chlamydia pneumoniae causes a mild form of pneumonia. Chlamydia are cultivated in laboratory animals, in cell cultures, or in the yolk sac of chicken embryos.

The chlamydia

_____may be the most common infectious bacterial genus. They live only inside the cells of their hosts, usually insects, a relationship called endosymbiosis

Wolbachia (The -(alpha) Proteobacteria )

______, transmitted by fleas, is the cause of plague.

Yersinia pestis

The genus _____is important in the operation of activated-sludge sewage systems.

Zoogloea The -(beta) Proteobacteria

1. Cause of whooping cough (pertussis). 2. Produces a food-poisoning enterotoxin. 3. Endospores. 4. Plague. 5. Important for operation of an activated-sludge sewage system. 6. Observed to fix nitrogen while living in close association with certain tropical grasses. 7. A filamentous bacterial pathogen.

b. Bordetella pertussis e. Staphylococcus aureus f. Clostridium tetani d. Yersinia pestis g. Zoogloea spp. i. Azospirillum h. Nocardia asteroides

______-hemolytic types of bacteria form a clear zone of hemolysis on blood agar plates.

beta

1. Genus Homo. 2. Genus Sulfolobus. 3. Genus Staphylococcus. 4. Genus Chlamydia.

c. Domain Eukarya b. Domain Archaea a. Domain Bacteria a. Domain Bacteria

1. A genus of gliding bacteria that is an important cellulose degrader. 2. A sheathed bacterium. 3. A chemoautotrophic bacterium that participates in nitrification in soil. 4. Photosynthetic bacteria that may fix nitrogen. 5. Photosynthetic, anoxygenic bacteria. Often use reduced-sulfur compounds for energy and sulfur granules accumulate in the cells.

e. Cytophaga c. Sphaerotilus natans a. Nitrosomonas b. Cyanobacteria d. Purple sulfur or green sulfur bacteria

The ______are highly pleomorphic because they lack a cell wall. They are exceptionally small, having the smallest genome of any bacteria. Related by DNA analysis to certain gram-positive bacteria, they appear to have lost genetic material (degenerative evolution). Among the mycoplasmas is Mycoplasma pneumoniae, which causes a mild pneumonia; Spiroplasma, which is a plant pathogen and insect parasite; and Ureaplasma, which enzymatically splits urea and is occasionally associated with urinary tract infections.

mycoplasmas