Bacteria Nutrition, Growth, Physiology, and Metabolism Flashcards
What are the general macronutrient requirements? Micro?
water, carbon, oxygen, hydrogen, sulfur, phosphorus; iron and others
What is the category of bacteria that chelate iron?
siderophores; possible drug target
What is an obligate aerobe?
require O2 to grow, used as the terminal acceptor, undergo respiration
What is a microaerophiles?
aerobes but grow best with less oxygen than in the air, O2 used as terminal acceptor, use respiration
What is an obligate anaerobe?
unable to synthesize an oxygen-linked respiratory chain, don’t use O2 as terminal acceptor instead use organic compounds, utilize fermentation
What is an aerotolerant anaerobe?
oxygen indifferent, can grow in presence of O2 but use organic compounds as final acceptor, fermentation
What is a facultative anaerobe?
can grow in presence or absence of O2, will use it as final electron acceptor if its available (respiration) but will use organic compounds if its not available (fermentation)
What is a psychrophile? Examples.
grows at fridge temps (0-30C); listeria
What is a mesophile? Examples of some that prefer a little colder than human body temp?
grows at 10-45 C, human pathogen, most other bacteria; mycobacterium leprae (31), sporothrix schemkii (25), and rhinovirus (33)
What is a thermophile?
grows at 25-100C, hot springs bacteria
What is the optimal pH range for most bacteria?
6.5 - 7.5`
What is a halophile? Examples.
grow in hypertonic or high salt (sugar) concentration, Staph aureus and enterococcus are both facultative halophiles
What is generation time?
time required for population to double
What are the phases of growth?
lag, log, stationary, and death
What are the features of log phase of growth?
constant, min generation and max rate of reproduction, most AB susceptible, quorum sensing in late log
What are the features of lag phase of growth?
active metabolism, no division, inducible enzymes due to nutrients and constitutive enzymes- required an always present
What are the features of stationary phase?
nutrient depletion, waste accumulation, decrease in rate of cell division (decrease metabolic rate)
What are the features of death phase?
increase in death rate, autolysis
What is quorum sensing?
cell density regulated gene expression, could be a toxin or sporulation, cell to cell communication, essential for virulence of most pathogens studied
What are persistor cells?
metabolically dormant, responsible for : increased antibiotic resistance and chronic recurrent infections
In anaerobic respiration what metabolic systems/enzymes are used?
up to some of the cytochromes of the ETC to transfer electrons to an alternate acceptor (some, aerobes, facultative anaerobes and anaerobes)
In anaerobic respiration what is sometimes utilized for the final electron receptor? Why is this important clinically?
nitrate to nitrite, can test in urine for UTI, (some aerobes)
What is a B enzyme?
a virulence factor, breaks complex molecules (polysaccharides, fats and proteins) into simple form
