Table of Contents
What is the Aerobactin system?
Aerobactin is a bacterial iron chelating agent (siderophore) found in E. coli. It is a virulence factor enabling E. coli to sequester iron in iron-poor environments such as the urinary tract.
What is K antigen E coli?
The K-1 antigen, a capsular homopolymer of sialic acid, and S-fimbriae are considered amongst others as major determinants of virulence among E. coli strains that cause neonatal meningitis. Contrary to ExPEC, disease caused by intestinal pathogenic E. coli often occurs in outbreaks.
How is iron acquired?
Iron Acquisition from Heme and Heme-Containing Proteins. One strategy for microbes to obtain iron during infection of mammals is to target heme, hemoglobin, or complexes containing these molecules (e.g., haptoglobin-hemoglobin, hemopexin-heme).
Is Enterobactin a siderophore?
Enterobactin is an archetypical siderophore with exceptionally high affinity for Fe3+ (Ka = 1052)9. Many Gram-negative bacteria, including E. coli10, produce and take up this siderophore.
How does E. coli uses the compound Enterobactin?
Enterobactin is a catechol-containing siderophore produced by E. coli. Under iron deprivation conditions, E. coli synthesizes these low molecular weight compounds, which bind ferric ions with high affinity and which are used to supply iron for metabolic pathways.
What is the main function of siderophores?
Siderophores are small molecular iron chelators that are produced by microbes and whose most notable function is to sequester iron from the host and provide this essential metal nutrient to microbes.
What are the significant roles of siderophores?
The role of siderophores is primarily to scavenge Fe, but they also form complexes with other essential elements (i.e. Mo, Mn, Co and Ni) in the environment and make them available for microbial cells (Bellenger et al., 2008; Braud et al., 2009a,b).
Why capsular antigen is called K antigen?
LPS contains O-linked polysaccharides (O-PS) comprised of repeating oligosaccharide units. The O-PS repeating units can be referred to as the O-antigens due to their immunogenicity. Some bacteria produce capsular polysaccharides (CPS), which are referred to as the K-antigens to distinguish them from the O-antigens.
Where is K antigen found?
One of the major virulent determinants of Gram-negative bacteria is capsular polysaccharide or K antigen located on the bacterial outer membrane surface, which is a potential drug & vaccine target.
How do bacteria absorb iron?
Moreover, iron is absorbed in the presence of fermentable carbohydrates that stimulate “the growth of bacteria that produces short-chain fatty acid such as propionic acid”, which increases mineral intake [83]. Micronutrient deficiencies are mostly observed in impoverished populations.
What is iron sequestration?
Iron sequestration is a recognized innate immune mechanism against invading pathogens mediated by iron-binding proteins called transferrins. Despite many studies on antimicrobial activity of transferrins in vitro, their specific in vivo functions are poorly understood.
What is siderophores in plants?
Siderophores are organic compounds with low molecular masses that are produced by microorganisms and plants growing under low iron conditions.
How does E coli uses the compound Enterobactin?
Is Enterobactin chiral?
The chirality of the iron center in enterobactin is Δ,6 and this chirality, while not essential for receptor recognition and outer membrane transport,7is essential for iron utilization; the mirror image enantio-enterobactin complex does not promote microbial growth.
Why do bacteria need siderophores?
Where are siderophores located?
Siderophores are a structurally diverse class of natural products commonly found in bacteria and fungi that chelate iron(III).
What is AK antigen?
Commonly but imprecisely called “Kell,” this is the most important antigen in the Kell blood group system. This antigen also goes by the name “KEL1.” While K is a relatively low-frequency antigen (present in only about 9% of Caucasians and 2% of African-Americans), it is very important for several reasons.
What is the role of yersiniabactin in the pathogenicity of Yersinia pestis?
As a part of such an iron-uptake system, yersiniabactin plays an important role in pathogenicity of Y. pestis, Y. pseudotuberculosis, and Y. entercolitica . Yersiniabactin is a four ring structure composed of carbon, hydrogen, nitrogen, oxygen, and sulfur.
What is ybtA yersiniabactin?
YbtA is believed to be a transcriptional activator of the yersiniabactin receptor and of the siderophore biosynthetic genes (22). Bearden et al. (3) have identified an approximately 22-kb region of the pgmlocus of Y. pestiswhich encodes several iron-regulated proteins.
Does yersiniabactin system have a role in vivo virulence?
Such a wide dissemination of HPI and its impact on the virulence of Yersiniaimplies an important, possible multifunctional role of yersiniabactin system in vivo and the availability of an efficient mechanism for its genetic transfer. ACKNOWLEDGMENTS
How many yersiniasiderophore yersiniabactin genes are there?
The ability to synthesize and uptake the Yersiniasiderophore yersiniabactin is a hallmark of the highly pathogenic, mouse-lethal species Yersinia pestis, Y. pseudotuberculosis, and Y. enterocolitica1B. We have identified four genes, irp1, irp3, irp4, and irp5, on a 13-kb chromosomal DNA fragment of Y. enterocoliticaO8, WA-314.