The-rcsA-gene-of-Klebsiella-pneumoniae-O1--K20-is-involved-in-reflexion-of-the-serotypespecific-K--capsular--antigen-a

In klebsiella pneumoniae , the ability to synthesize declamatory amounts of capsular polyose is an significant correlate of virulence . We composition the cloning of rcsA from K. pneumoniae serotype O1 : K20 and exhibit that rcsA is postulate in the locution of the K antigen capsulate . We have determined the base episode for the rcsA gene from K. pneumoniae K20 and shown it to be superposable to the episode reported previously for rcsA from try K21 ( Allen et al. , J .

Gen. Microbiol . 133:331-340 , 1987 ) . Polysaccharides argue that this gene is wide distributed among different klebsiella K serotypes . When clone into Escherichia coli K-12 , the K. pneumoniae rcsA gene induce a mucoid phenotype , resulting from the activating of colanic acid synthesis . Activation of colanic acid synthesis was not subordinate on outgrowth at low temperatures ( less than or match to 30 stage C ) .

The K. pneumoniae rcsA gene complemented E. coli K-12 rcsA sport but could not accompaniment defects in rcsB , suggest that RcsA may be functionally homologous in these bacteria . The clone rcsA gene also complement a defect in nonmucoid strain K20 differential that normally produced only trace total of K20 antigen and were unable to forgather a wild-type capsular construction . variation that were K20-deficient were not complement . The K antigen capsule of K. pneumoniae so joins a ontogenesis list of polysaccharide-synthetic organization in which `` RcsA-like proteins are involved .

functional analysis of conserved gene ware involved in forum of escherichia coli capsules and exopolysaccharides : evidence for molecular recognition between Wza and Wzc for colanic acid biosynthesis.Group 1 capsular polysaccharides ( CPSs ) of escherichia coli and some loosely cell-associated exopolysaccharides ( EPSs ) , such as colanic acid , are assembled by a Wzy-dependent polymerization arrangement . In this biosynthesis pathway , Wza , Wzb , and Wzc homologues are required for coat expression of wild-type CPS or EPS . Multimeric complexes of Wza in the forbidden membrane are believe to provide a conduct for polymer exportation ; Wzc is an interior membrane tyrosine autokinase and Wzb is its consanguine phosphatase . This field was perform to determine whether the Wza , Wzb , and Wzc proteins for colanic acid expression in E. coli K-12 could function in the E. coli K30 image group 1 capsulize system .

When expressed unitedly , colanic acid Wza , Wzb , and Wzc could complement a wza-wzb-wzc flaw in E. coli K30 , advise preservation in their collective function in Wzy-dependent CPS and EPS systems . Expressed separately , colanic acid Wza and Wzb could also function in K30 CPS construction . In contrast , the geomorphologic essential for Wzc work were more stringent because colanic acid Wzc could restore translocation of K30 CPS to the cell surface only when express with its cognate Wza protein . Chimeric colanic acid-K30 Wzc proteins were constructed to further study this interaction . These proteins could repair K30 biosynthesis but were ineffectual to span synthesis to export . The chimeral protein consist the periplasmic field of colanic acid Wzc was functional for effective K30 CPS coat expression only when coexpressed with colanic acid Wza .

Purchase today of Wza-Wzc interactions in radical 1 CPS assembly.Cation complexation by mucoid Pseudomonas aeruginosa extracellular Mucoid Pseudomonas aeruginosa is a prevalent cystic fibrosis ( CF ) lung colonizer , producing an extracellular matrix ( ECM ) composed predominantly of the extracellular polyose ( EPS ) alginate . The ECM limits antimicrobial penetration and , accordingly , CF sufferers are prostrate to chronic mucoidal P. aeruginosa lung transmission . Interactions betwixt cations with rarefied assiduousness in the CF lung and the anionic EPS , raise the geomorphologic rigidness of the biofilm and exasperate virulence . In this work , two large mucoidal P. aeruginosa EPS models , free-base on β-D-mannuronate ( M ) and β-D-mannuronate-α-L-guluronate organisation ( M-G ) , and encompassing thermodynamically unchanging acetylation configurations-a morphologic theme unequalled to mucoid P .

aeruginosa-were created . employ extremely precise initiative rule calculations , stable coordination environs dramatize by the cations have been place and thermodynamic stability quantify . These models show the weak cross-link capability of Na+ and Mg2+ ions relative to Ca2+ ions and indicate a preference for cation adhere within M-G immobilize due to the smaller torsional rearrangements need to divulge static binding sites .