Microbiology-Ch. 11 Study Guide-Prokayotes

Coxiella

C. burnetii is only characterized species Obligate intracellular bacterium; can survive outside host cell as spore-like structures called small-cell variants (SCVs) formed during intracellular growth Not as resistant as endospores to heat, disinfectants

Obligate Intracellular Parasites

Cannot reproduce outside a host cell: host cells supply compounds they would otherwise need to synthesize Most have lost ability to synthesize needed substances Multiple bacterial examples; all are tiny Gram-negative rods or coccobacilli

Oxygenic phototrophs-cyanobacteria

Earliest oxygenic phototrophs, primary producers; Anabaena Use water as source of electrons for reducing power

Proteus

Implicated in many infections of the urinary tract and in wounds

Obligate aerobes

Microorganisms that can survive only in the presence of oxygen. To obtain energy, these organisms metabolize substances like sugar or fats through cellular respiration. Oxygen acts as the terminal electron acceptor. They gather at the top of the tube where the oxygen concentration is highest

Aerotolerant anaerobes

Organisms cannot use oxygen for growth but tolerate its presence. Use fermentation to produce ATP eg Strep

Obligate anaerobes

Organisms that cannot live where molecular oxygen is present Gather at the bottom of the tube where the oxygen concentration is lowest

Aerobic chemoorganotrophs

Oxidize organic compounds for energy; use oxygen as TEA Some inhabit specific environments, others ubiquitous Gram-positive cocci Found in soil, dust particles, inanimate objects, skin Pigmented colonies Tolerate dry, salty conditions

Hyperthermophiles

Pyrodictium (barophile) Sulfolobus (Thermoacidophilic) Domain: Archaea

Describe the contribution of Cornelis B. van Neil.

Studied photosynthetic purple bacteria Demonstrated requirement of light for growth No evolution of oxygen Oxidize hydrogen sulfide during CO2 fixation Noted remarkable similarity of photosynthetic reactions in all photosynthetic organisms

Enterococcus

Grows in low oxygen like intestinal tract and vagina and also in human stool They persist as contaminants in a hospital environment like hands and bedding Leading cause of hospital infections due to high resistance to antibiotics

Rhizobia

Bacteria that Associate with Plants Gram-negative rods that often fix nitrogen

Gram negative rods

Bacteria that Inhabit Mucous Membranes

Gram positive rods

Bacteria that Inhabit Mucous Membranes Purple

How many genera and species of bacteria are classified currently?

950 genera

Gram positive irregular rods

Bacteria that Inhabit Mucous Membranes Respiratory, genitourinary, intestinal tracts inhabited by numerous kinds of bacteria

M. pneumoniae

A type of "atypical" bacteria that commonly causes mild infections of the respiratory system Antibiotics that target peptidoglycan synthesis not effective Medically important Genus: Mycoplasma

Gram positive cocci_

Bacteria that Inhabit the Skin

Streptomyces G+

Aerobic Gram-positive bacteria Terrestrial Growth resembles fungi: form mass of branching hyphae called mycelium Chains of spores (conidia) develop at tips Conidia resistant to drying; easily spread by air currents Produce extracellular enzymes, geosmins

Anaerobic chemoorganotrophs-fermentation

Aka: Chemoheterotrophs Oxidize glucose to obtain energy (use organics for energy and carbon) Numerous anaerobic bacteria ferment, different organic energy sources, end products. E.g. Clostridium, lactic acid bacteria

Salmonella

Almost all members are potentially pathogenic, gram negative rod Inhabit intestines of poultry and cattle Salmonella typhi- causative agent of typhoid fever Other members of this genus causes salmonellosis, one of the most common foodborne illness

Facultative anaerobes

An organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent. They use oxygen as electron acceptor. They gather mostly at the top because aerobic respiration generates more ATP than either fermentation or anaerobic respiration.

Microaerophiles

An organism that need oxygen because they cannot ferment or respire anaerobically. However, they are poisoned by high concentrations of oxygen. They gather in the upper part of the test tube but not the very top. Eg H. Pylori or Campylobacter

Treponema

Are obligate anaerobes or microaerophiles; often inhabit mouth, genital tract

Bifidobacteria

Are used in treatment as so-called "probiotics," Used to treat skin infections, excema

Agrobacterium

Bacteria that Associate with Plants Gram-negative rods Genetically modify plants via plasmid to form tumors DNA encodes ability to synthesize plant growth hormone; results in tumor Also encodes synthesis of unusual amino acid derivative opine Use opine as nutrient

Yersinia

Bubonic plague, transmitted by fleas

What causes Q fever and is most often acquired by inhaling bacteria shed from infected animals?

C. burnetii

Facultative anaerobes

Can live with or without oxygen Enterics Gram negative rods , E.coli Obtain energy from fermentation reactions, use organics as energy source Various end products

B. recurrentis and B. hermsii

Cause relapsing fever Genus: Borrelia

B. burgdorferi

Causes Lyme disease Genus: Borrelia

S. mutans

Causes cavities (dental caries) Genus: Streptococcus

C. diphtheriae

Causes diphtheria Toxin producing strain Genus: Corynebacterium

S. pyogenes

Causes scarlet fever, sore throat (pharyngitis), rheumatic fever Genus: Streptococcus

T. pallidum

Causes syphilis, difficult to culture Genus: Treponema

H. pylori

Causes ulcers, produces urease(breaks down to CO2 and NH3<-alkalizes, which breaks down urea to ammonia to neutralize local pH Multiple flagella Peptic ulcers Stomach cancer

Name the features common to most bacteria.

Cell wall Flagella Capsule Pili Fimbre

Anaerobic chemolithotrophs

Chemolithotrophs oxidize reduced inorganic chemicals to obtain energy; E.g., H2, CO2, sulfur Anaerobes use alternative electron acceptor

Anaerobic chemoorganotrophs-respiration

Chemoorganotrophs oxidize organic compounds (e.g., glucose) to obtain energy Sulfur- and Sulfate-Reducing Bacteria; sulfur cycle *Anaerobes often use sulfur, sulfate as electron acceptor *Hydrogen sulfide (rotten-egg smell) ;Gram-negative curved rods & some archaea

Archaea

Domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycan Thrive in extremes High heat, acidity, alkalinity, salinity Many others detected in non-extreme environments using molecular techniques

B. anthracis

Facultative anaerobe Causative agent of anthrax Genus: Bacillus

Klebsiella

Found in soil or water K. pneumonia: contains a capsule; causes a serious form of pneumonia in humans 50% mortality rate Facultative Anerobic Gram negative rod

Shigella

Found only in humans Second only to E. coli as a cause of traveler's diarrhea

Aerobic chemolithotrophs

Gain energy by oxidizing inorganic chemicals(S); but use O2 as TEA *Energy from oxidation of sulfur, sulfur compounds including H2S, thiosulfate; responsible for sulfur cycles Sulfur-oxidizing bacteria: Gram-negative rods, spirals; Beggiatoa

Pseudomonas

Gram-Negative Rods Aerobic rods Fluoresce under UV light Motile by flagella Metabolically diverse P. aeruginosa Infects urinary tract, burns, wounds Can grow on antiseptics and are resistant to most antibiotics Responsible for 1 in 10 hospital infections

Bacillus

Gram-Positive Rods Endospore forming Few are pathogenic

Clostridium

Gram-Positive Rods Obligate anaerobes Common in soils; vegetative cells live in anaerobic microenvironments created by aerobes consuming O2 Endospores tolerate O2, survive long periods of heat, drying, chemicals, irradiation; Germinate when conditions improve (eg ingested makes anaerobic environment) Diverse metabolism; some cause diseases Endospore-producing: C. tetani: tetanus C. botulinum: botulism C. perfringens: foodborne diarrhea

Neisseria

Gram-negative cocci with fimbrae, typically kidney bean-shaped cocci found in pairs Aerobic cocci

Haemophilus

Gram-negative coccobacilli "Blood-loving": require hematin and/or NAD blood Many common microbiota of respiratory tract H. influenzae causes ear infections, respiratory infections, meningitis Greatest cause of childhood meningitis before Hib vaccine Encapsulated forms from csf H. ducreyi causes STD chancroid

Bacteroides

Gram-negative rods and coccobacilli Small; strict anaerobes that inhabit mouth, intestinal tract, genital tract of humans and other animals B. fragilis and related species comprise ~1/3 of bacteria in human feces Pleomorphic Non endospore formers Opportunistic infections

Purple bacteria

Gram-negative; appear red, orange, or purple Photosynthetic apparatus in cytoplasmic membrane

Green bacteria

Gram-negative; typically green or brownish

Staphylococci

Gram-positive cocci Facultative anaerobes; catalase-positive Most harmless (e.g., S. epidermidis)

Micrococcus

Gram-positive cocci Found in soil, dust particles, inanimate objects, skin Pigmented colonies Tolerate dry, salty conditions

Streptococci

Gram-positive cocci that occur in chains. Generally aerotolerant anaerobes Responsible for more illness than any other group Produce products that destroy phagocytic cells Some digest connective tissue which causes it to spread

Bifidobacterium

Gram-positive irregular rods Anaerobes; reside primarily in intestinal tract of humans and other animals Predominant members of intestinal microbiota of breast-fed infants; thought to exclude pathogens

Corynebacterium

Gram-positive pleomorphic rods Obligate Aerobes Wide-spread Often club-shaped and form V shapes or palisades Referred to as coryneforms or diphtheroids Generally facultative anaerobes; some strict aerobes Many harmless

Green Sulfur Bacteria

Habitats similar to purple sulfur bacteria Form granules outside of cell Accessory pigments located in chlorosomes Lack flagella May have gas vesicles Strict anaerobes None are chemotrophic Representatives include: Chlorobium, Pelodictyon

Halophiles

Halobacterium Domain: Archaea

Dichotomous key

Identification scheme Paired questions; answering one question leads to another paired question until Identification of organisms

Borrelia

Includes three pathogens, transmitted by ticks and lice Genome is linear chromosome and many linear and circular plasmids

Why is Nitrogen-fixing cyanobacteria critical ecologically?

Incorporate N2 and CO2 into organic material Form usable by other organisms

Mycoplasma

Lack cell wall, gives flexibility Pleomorphic 0.1 - 0.24 µm Most have sterols for added strength and rigidity Among smallest forms of life; genomes thought to be minimum size encoding essential functions Colony growth produces characteristic "fried egg" appearance

What is the major metabolic end product of Streptococcus species?

Lactic acid

Purple sulfur bacteria

Large cells; some motile May have gas vesicles to control depth Most store sulfur in intracellular granules Preferentially use H2S to generate reducing power Some can grow aerobically in absence of light

Geosmins

Metabolic products in soil from the microbes Medically useful antibiotics including streptomycin, tetracycline, erythromycin

Methanogens

Methanobacterium Domain: Archaea

Campylobacter

Microaerophilic Gram Negative Curved Rods C. jejuni (causes diarrhea in humans)

Purple Non-Sulfur Bacteria

Moist soils, bogs, paddy fields Preferentially use organic molecules instead of H2S as source of electrons Lack gas vesicles May store sulfur; granules form outside cell Remarkably diverse metabolism

Current methods to classify bacteria.

Morphological characteristics: Useful for identifying eukaryotes Differential staining: Gram staining, acid-fast staining Biochemical tests: Determines presence of bacterial enzymes

S. pneumoniae

Most common cause of pneumonia Genus: Streptococcus

E.coli

Most common inhabitant of human intestinal tract Most well characterized organism in microbiology Main cause of traveler's diarrhea

Lactobacillus species are common members of the normal microbiota of which human body sites?

Mouth Intestinal tract Vagina

Metabolic Diversity in the prokaryotes

Numerous approaches to harvesting energy to produce ATP PCR indicates up to 10,000 bacteria/gm of soil. Many bacteria have not been identified or characterized because they: Haven't been cultured Need special nutrients Are part of complex food chains requiring the products of other bacteria Need to be cultured to understand their metabolism and ecological role

Mycobacterium

Obligate Aerobes Acid-fast bacteria Mycolic acid in cell wall prevents Gram-staining Special staining used; resist destaining Generally pleomorphic rods Notable pathogens: M. tuberculosis, M. leprae More resistant to disinfectants, differ in susceptibility to antimicrobial drugs Related Nocardia species also acid-fast

Oxygen requirements.

Obligate Aerobes eg Micrococcus Obligate Anaerobes eg Clostridium Facultative anaerobes eg most common in your ecoli

Name the four features common to all bacteria.

Plasma membrane Cytoplasm Ribosomes DNA

Cyanobacteria

Produce oxygen Use water as source of electrons for reducing power Still play essential role as primary producers: Harvest sunlight to convert CO2 into organic compounds Diverse group of Gram-negative bacteria

What roles do hydrogen gas and carbon dioxide play in the metabolism of methanogens?

Produces methane

Obligate aerobes

Require O2 for cellular respiration Micrococcus

Previous methods to classify bacteria.

Shape Gram Stain Metabolism (growth in oxygen)

S. aureus

Skin and wound infections; food poisoning Medically important Genus: Staphylococcus

Rickettsia

Slime layer Rocky Mountain spotted fever Obligate Intracellular Parasite Include species responsible for several serious arthropod-transmitted human diseases

Bergeys Manual of Bacteriology

The main resource for determining the identity of prokaryotic organisms, emphasizing bacterial species, using every characterizing aspect.

Acidophiles

Thermoplasma Domain: Archaea

Gram negative Spirochetes

Treponema and Borrelia

G-rods Enterobacteriaceae

Typically found in intestinal tract of humans, other animals; some thrive in soil Facultative anaerobes that ferment glucose Normal intestinal microbiota include Enterobacter, Klebsiella, Proteus, most E. coli strains Those that cause diarrheal disease include Shigella, Salmonella enterica, and some E. coli strains Life-threatening systemic diseases include typhoid fever (Salmonella enterica serotype Thyphi) and bubonic and pneumonic plague (Yersinia pestis) Lactose fermenters termed coliforms

S. saprophyticus

Urinary tract infections Medically important Genus: Staphylococcus

Vibrio

vibrio-lowercase; shape Vibrio-uppercase; genus Gram-Negative Curved Rods Facultative anaerobic curved rods Found in coastal water; transmitted by raw shellfish Causes cholera (profuse diarrhea)