BMSC210 CH4.4 Flashcards
What color do gram-positive prokaryotes appear after Gram staining?
Purple
What additional characteristics can be used to classify gram-positive prokaryotes?
G+C ratios in DNA and composition of 16S rRNA subunits
What is the class of gram-positive bacteria with high G+C ratios in their DNA?
Actinobacteria
Where do most Actinobacteria live?
Soil but some are aquatic
What are obligate aerobes?
Aerobes that require oxygen for growth
How do obligate aerobes divide?
By snapping, forming V-like pairs of daughter cells
What is the role of obligate aerobes in bioremediation?
They degrade phenol and can be used for bioremediation
What unique characteristic does Streptomyces have?
Aerobic, spore-forming bacteria
What is the DNA composition of low G+C gram-positive bacteria?
Less than 50% guanine and cytosine
Where can endospores be found?
Anaerobic habitats like soil and aquatic sediments rich in organic nutrients
How long can endospores survive?
Many years
What are the genera included in the order Lactobacillales?
Lactobacillus, Leuconostoc, Enterococcus, and Streptococcus
What is another name for necrotizing fasciitis?
Flesh eating disease
What does the class Bacilli include?
Bacteria with diverse shapes including bacillus and cocccus
What can bacteria in the genus Bacillus produce?
endospores
What are some industries that use Bacillus spp.?
antibiotics, enzymes, detergents
What does the name Staphylococcus mean?
bunches of grapes
What are the characteristics of Staphylococcus spp.?
facultative anaerobic, halophilic, nonmotile
What are some antibiotic-resistant strains of S. aureus?
MRSA and VRSA
Why are MRSA and VRSA difficult to treat?
Resistance to nearly all available antibiotics
Where are MRSA and VRSA a serious threat?
Hospitals, nursing homes, dialysis facilities
How are Mycoplasmas different from other bacteria?
They do not possess a cell wall.
Are Mycoplasmas stained by Gram-stain reagents?
No.
What does it mean for the cells to be pleomorphic?
They may take on a variety of shapes
What is the microscopic morphology of Enterococcus?
Gram-positive coccus; forms microscopic pairs
What are the unique characteristics of Enterococcus?
Anaerobic aerotolerant bacteria; may cause infections in nosocomial environment
What is the microscopic morphology of Lactobacillus?
Gram-positive bacillus
What are the unique characteristics of Lactobacillus?
Facultative anaerobes; ferment sugars into lactic acid; part of the vaginal microbiota; used as probiotics
What is the microscopic morphology of Leuconostoc?
Gram-positive coccus; may form microscopic chains
What are the unique characteristics of Leuconostoc?
Fermenter; used in food industry to produce sauerkraut and kefir
What are the unique characteristics of Mycoplasma?
Smallest bacteria; have no cell wall; causes ‘walking’ pneumonia
What is the microscopic morphology of Staphylococcus?
Gram-positive coccus; forms microscopic clusters in culture that resemble bunches of grapes
What are the unique characteristics of Staphylococcus?
Tolerate high salt concentration; facultative anaerobes; produce catalase; S. aureus can also produce coagulase and toxins responsible for local (skin) and generalized infections
What is the microscopic morphology of Streptococcus?
Gram-positive coccus; forms chains or pairs in culture
What are the unique characteristics of Streptococcus?
Diverse genus; classified into groups based on sharing certain antigens; some species cause hemolysis and may produce toxins responsible for human local (throat) and generalized disease
What is the microscopic morphology of Ureaplasma?
Similar to Mycoplasma
What are the unique characteristics of Ureaplasma?
Part of the human vaginal and lower urinary tract microbiota; may cause inflammation, sometimes leading to internal scarring and infertility
