Expression of a(n) ________ alters gene transcription in E. coli by activating transcription of specialized heat stress response genes
Fill in the blank(s) with correct word
alternative sigma factor
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Salmonella is commonly associated with wound infections
Indicate whether the statement is true or false.
A mutation in E. coli results in the loss of both restriction endonucleases and modification enzymes. Would you expect any difference in the frequency of gene transfer via transduction FROM Salmonella INTO this E. coli strain?
A. No-since the Salmonella strain is normal, the rate of production of transducing virus particles would still be the same, resulting in the same frequency of gene transfer. B. Yes-the loss of the restriction endonucleases would leave the recipient E. coli unable to break down "invading"' viral DNA from the transducing phage. This would lead to higher rates of successful transduction. C. Yes-the loss of the modification enzymes would leave the recipient E. coli unable to tag its own DNA as "self," leaving the viral DNA untagged and recognizable as "foreign," and targeted for destruction. This would lead to higher rates of successful transduction. D. No-transduction efficiency isn't affected by either restriction endonucleases or modification enzymes, so there'd be no effect on the overall rate. E. Yes-the loss of the restriction endonucleases would leave the recipient E. coli unable to break down "invading" viral DNA from the transducing phage, AND the loss of the modification enzymes would leave the recipient E. coli unable to tag its own DNA as "self," leaving the viral DNA untagged and recognizable as "foreign," and targeted for destruction. Together, thesewould lead to higher rates of successful transduction.
A cell may meet the demand for large quantities of a specific protein by:
a. blocking transcription of the gene that encodes the protein. b. decreasing the half-life of the mRNA that specifies the protein. c. adding methyl groups to the gene that encodes the protein. d. gene amplification e. inhibition of DNA synthesis
You have isolated a gram-positive bacterium with low G + C content. It was a contaminant in unpasteurized milk. It infected a pregnant woman, and now you are worried that her child will be stillborn. What bacterium is it?
a. Anabaena b. Listeria monocytogenes c. Clostridium d. Mycobacterium