Question

cultures of a bacterial strain were incubated in a refrigerator (5°c), on a lab bench (22°c), in a 37°c incubator, and in a 50°c incubator. after incubation, there was no growth at 37°c and 50°c, slight growth in the refrigerator, and abundant growth on the lab bench top. which term best describes this organism?
a psychrotolerant
b capnophile
c anaerobe
d mesophile
e halophile

Explanation:

• Psychrotolerant bacteria can grow at lower temperatures (like \(5^{\circ}C\) in the refrigerator) and also at moderate temperatures (such as \(22^{\circ}C\) on the lab bench). They do not grow well at higher temperatures (\(37^{\circ}C\) and \(50^{\circ}C\) in this case).
• Capnophiles require high levels of carbon dioxide for growth - no information about \(CO_2\) requirements is given here.
• Anaerobes are related to oxygen requirements (e.g., obligate anaerobes cannot grow in the presence of oxygen, facultative anaerobes can grow with or without oxygen) - no oxygen - related information is provided.
• Mesophiles have an optimal growth temperature around \(37^{\circ}C\) (body temperature for many mesophiles associated with warm - blooded animals), but in this case, there is no growth at \(37^{\circ}C\).
• Halophiles require high salt concentrations for growth - no salt - related information is given.

Answer:

A. Psychrotolerant