Sigma B Is a Stress-Induced Transcription Factor in Bacillus Subtilis

question 11

Multiple Choice

Sigma B is a stress-induced transcription factor in Bacillus subtilis. Bacteria producing a sigma B-YFP fusion protein were exposed to constant energy stress, and fluorescence pulses emitted by individual cells were detected by time-lapse microscopy. Could this result have been obtained using a sigma B-b-gal fusion protein?

• A) Yes. Hydrolysis of X-Gal by b-galactosidase produces a blue product detectable by eye.
• B) Yes. Hydrolysis of ONPG by b-galactosidase in liquid medium produces an orange compound measurable by spectrophotometry.
• C) Yes. It depends on how well the reporter gene is inserted into the vector with respect to the position of the ribosome-binding site.
• D) No. Whereas YFP fluorescence can be carefully observed and measured by time-lapse microscopy, b-gal activity is measured as an average of the population as a whole.
• E) No; the product would not be detectable by eye.

---

Definitions:

Reflexes

Automatic, involuntary responses to specific stimuli, such as the knee-jerk reaction, which serve protective roles for the body.

Gerontology

The study of aging and the challenges encountered as individuals grow older, including the biological, psychological, and social aspects of aging.

Conception To Death

A term describing the entire human lifecycle, from fertilization of the egg to the end of life.

Scheme

In cognitive development, a systematic pattern of thoughts, actions, and strategies that are developed and utilized in the process of learning and problem-solving.