Essay - Molecular Biology Clostridium Difficile How Important is the Experimental Question...


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Molecular Biology Clostridium difficile

How important is the experimental question being addressed to ***** field?

***** study of Matamorous, England, and Dupuy (2007) aimed to present two things. First, the authors would like to provide evidence that TcdC negatively regulates the synthesis ***** Clostridium ***** toxins. Second, the authors also wanted to show that TcdC destabilizes ***** TcdR-containing holoenzyme. This further suggests that TcdC has an ability ***** regulate toxin expression in its unique way. To understand the relevance of ***** two objectives *****cited, it must first be established what ***** is. TcdC gene ***** found at the right end of the pathogenicity locus (PaLoc) of C. difficile. It is found along with other genes such as TcdA, TcdB, and TcdR, genes that positively regulate the production ***** ***** A and B. It has *****en postulated that TcdC negatively ***** the gene expression of these toxin-producing ***** (Govind et al. 2006; Matamorous et al 2007). ***** is highly expressed when C. ***** are found to grow exponentially, and expression is silenced ***** cells enter the stationary p*****e; TcdC expression is upped when ***** toxin-producing *****s are shut **********. There have also been studies that demonstrated mutations in the ***** genes among epidemic strains that produce both *****xins ***** and B (Chernak and Johnson 2005; ***** et al. 2007).

Evidence to support the ***** aforementioned problems ***** relevant to the field of molecular and clinical biology. TcdC is a relatively new discovery. It is a membr*****ne-associated protein with a rel*****tively unknown regula*****ry mechanism. The virulence of C. difficile is due to the synthesis of *****xins produced by *****, TcdB, and TcdR *****. There has also ***** a *****ing number of ***** th*****t supports the presence of ***** mutations among ***** strains of C. difficile. To prove that Tcd***** negatively regulates TcdA, ***** and TcdR expression may allow a more in-depth underst*****ing of the pathogenesis of C. difficile. In turn, this may be a good *************** in developing medications ***** could combat ***** effects of this highly pathogenic microbe. An understanding of the negative regulatory effects ***** TcdC can help in addressing epidemic outbreaks.

Is the design of ***** experiment appropriate and efficient for the question? How else the experiment might ***** been designed ***** ***** an alternate design be b*****ter or worse?

***** quantitative, *****al study essentially had two major parts. First, the authors tested ***** ability ***** TcdC to repress ***** *****. This was demonstrated ***** using in vivo and ***** vitro models. TcdC repressive activity was compared to TcdR's augmentative effect in the expression of TcdA. Using C. perfingens to take ***** place ***** C. *****, β-glucuronidase ***** was used to measure promoter activity; the lack of β-glucuronidase activity in ***** absence ***** TcdR demonstrated that there ***** a consequent lack of tcdA expression. This was in contrast to the increase in b-glucuronidase ***** with TcdR. However, in the culture ***** an overexpression of *****, no glucuronidase activity was demonstrated despite ***** presence of TcdR. Its ability ***** repress

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