The mutation for drug resistance in Mycobacterium tuberculosis, the bacteria that causes the disease tuberculosis, occurs within the chromosome, not in the plasmid. How do you think this would affect the likelihood of an individual bacterium becoming drug resistant?

Agrobacterium tumefaciens is a bacterium that infects a wide range of broad-leaved plants. During infection, a plasmid called Ti is transferred into the plant cells, where that plasmid DNA is integrated into the plant’s genome. Some of the genes encoded by this plasmid are expressed by host cell machinery in the plant cell. These gene products produce plant hormones which stimulate cell division in the infected cells, causing the development of a plant tumor which provides an environment for that bacterium to grow.  You are studying a novel isolate of A. tumefaciens and want to determine which of the genes on the Ti plasmid are expressed in the bacterium, and which are expressed in the plant. You start by sequencing the Ti plasmid. a)  Considering the DNA sequence of Ti, describe two specific genetic features that would help you to differentiate whether a given gene is likely expressed in the plant or bacterium. b)  You collect plant tumor tissue, containing both bacterial and plant…

In a hypothetical situation, the gene for tetracycline resistance is located on a plasmid within a particular bacterium. This bacterium readily forms a pilus and donates one strand of the plasmid to another bacterium. What do you know about the bacterium with the tetracycline resistance? O It cannot receive a plasmid from another bacterium. O It must have the F factor gene because it can perform conjugation. O If it donates the plasmid, it will lose its own tetracycline resistance. O It has the Hfr gene and it can participate in transformation.

You are a graduate student working to construct a single gene knockout library of Leptospiria kirschneri, one the causative agents of leptospirosis. You are looking for single gene mutants which disrupt the bacterium’s spirillum shape to determine what role this rare cellular morphology may play in disease development and progression. Using an appropriate donor strain, you introduce the plasmid shown into L. kirschneri. L. kirschneri is not able to replicate the plasmid. The repeat regions are denoted on the plasmid map as vertical black lines, the transposase is denoted as tnp, and kanamycin kinase is denoted as aph. The larger of the two regions is transposed. Following selection and counter-selection, you isolate several non-spirillum colonies, which you use to infect juvenile piglets. Most of the infected piglets develop leptospirosis. Isolating L. kirschneri from these animals reveals that it has regained its spirillum morphology. What is a likely explanation for this reversion of…

Below are two pictures of perithecium on microscope slides that have been squished under cover slips so that the asci inside have spread out. In the asci, we can clearly see the tan ascospores (light colored) and wildtype ascospores (dark colored). We will perform our tetrad analysis by counting how many of the asci are non-recombinant and how many of the acsi are recombinant. We can tell which are recombinant and non-recombinant by observing the patterns of the ascospores in the asci. See the patterns of ascospores for non- recombinant and recombinant asci in the table below. Ascospore pattern of non-recombinant asci OOOO OOOOO You will count the total number of non-recombinant and recombinant asci in the two pictures below. You will only count the asci that have a star next to them because these asci can be clearly identified as non-recombinant or recombinant. Select the correct number below after you are done. Total number of non-recombinant asci [Select] Ascospore pattern of…

when various strains of lambda phage are seeded on a lawn of e.coli, they can form clear or turbid plaques. Explain the difference between the two types of plaques. can all bacteriophage form clear and turbid plaques?