Virulence factors bacterial

There are several other host factors present that should be mentioned that inhibit what are known as bacterial virulence factors. In general, these virulence factors are mechanisms that bacteria utilize to cause infection and/or ensure their survival. 

Volume 235. Bacterial Pathogenesis (Part A Identification and Regulation of Virulence Factors)... 

Bacterial virulence factor /8-solenoid with L-, T-type cross sections and left-handed twist... 

Finally, new infections organisms arise continnally. The fact is that we do not understand the microbial diversity on Earth. Here is an amazing, bnt not reassuring, example. The shotgun DNA seqnencing of hltered water sampled from the Sargasso Sea revealed 1.2 million new genes and 1800 new bacterial species. " Most of these are doubtless harmless to man bnt some have the potential to develop or acquire virulence factors and become a threat. 

If we think about it for a bit, quorum sensing as a mechanism regulating the production of virulence factors makes good sense for the bacterial population. If the bacterial population is too low, secretion of virulence factors would seem to be of little use too few bacteria secreting too few virulence factor molecules to serve whatever purpose these serve for the bacteria. It would seem better to wait until the bacterial forces have massed, then release the virulence factors and have some real impact. 

Obviously siderophores can be potent virulence factors of pathogenic bacteria. Siderophores in many cases have elaborate structures providing recognition only by the receptor site of the producing species. This renders a pirating by competing microorganisms more difficult. The structural specificities of siderophores have been used for classification purposes of bacterial species (see especially pyoverdins, Sect. 2.1). 

Depending upon the types of bacteria and the specific response a variety of different fatty acyl groups may be present in the inducer. Other responses include the formation of bacterial film (biofilms) on a surface and release of virulence factors that induce attack on a host. 

Urease (urea amidohydrolase) is an enzyme first identified over a hundred years ago in bacterial extracts [22], The presence of urease is a virulence factor for some pathogenic bacteria [23,24], It is now known to occur also in plants, fungi, and invertebrates (see [24,25] for reviews). Urease from jack bean was the first enzyme to be crystallized, in 1926. Almost 50 years later its metal content was reexamined and it was found to contain two atoms of nickel per subunit [26]. Finally in 1995 the crystal structure of the enzyme from the enteric bacterium Klebsiella aerogenes was determined [27], Amino-acid sequence comparisons predict that the structures of the plant and bacterial enzymes are similar, although with different subunit arrangements. 

M Dziejman, JJ Mekalanos. Two-component signal transduction and its role in the expression of bacterial virulence factors. In JA Hoch, TJ Silhavy, eds. Two-component signal transduction. Washington, DC ASM Press, 1995, pp 305-317. 

Bottcher T, Sieber SA (2009) Structurally refined p-lactones as potent inhibitors of devastating bacterial virulence factors. ChemBioChem 10 663-666... 

Salmonella in the gut lumen can induce a host inflammatory response mediated by several proteins excreted from the bacterial cytoplasm through Salmonella TTSS-1. These virulence factors may play a role in the influx of neutrophils into the intestine and the resulting inflammation that leads to diarrhea and other symptoms (Norris et al., 1998) (Fig. 5.1). Inflammation is an important component of innate immunity that plays a role in recruiting host immune cells to damaged tissue or invading microbes. Interaction with components of the innate immune system initiates a cascade of events that can lead to elimination of the microbe (Singh et al., 2009). 

---