Staphylococcus stability

The class I FruA isolated from rabbit muscle aldolase (RAMA) is the aldolase employed for preparative synthesis in the widest sense, owing to its commercial availability and useful specific activity of 20 U mg . Its operative stability in solution is limiting, but the more robust homologous enzyme from Staphylococcus carnosus has been cloned for overexpression [87], which offers unusual stability for synthetic purposes. Recently, it was shown that less polar substrates may be converted as highly concentrated water-in-oil emulsions [88]. 

Figure B3.5.12 Effect of mutations detected by CD. The far-UV CD spectra (A) show that the secondary structure of p-lactamase PC1 (solid line) from Staphylococcus aureus is essentially unaffected by point mutations P2 (Thr 140—>lle dashed line) and P54 (Asp 146->Asn dotted line). The crystallographic structure of P54 (Herzberget al., 1991) confirms that, apart from a loop region, the main body of the molecule that contains the thirteen tyrosine residues is very closely similar to that in the wild-type enzyme. The intensity of the tyrosine ellipticity (B) is, however, markedly decreased in each of the mutants, the lower thermodynamic stabilities of which support the interpretation of increased dynamics (Craig et al., 1985).

V8, as indicated by two-dimensional peptide maps of tryptic digests (44)- It appears, therefore, that various strains of S. aureus produce a major extracellular nuclease with covalent structures extremely similar to that of nuclease V8. Staphylococcus aureus has been reported, however, to produce several minor extracellular nucleases with different isoionic points and heat stabilities 45)- The covalent structures of these materials have not been studied. 

Of the several aldolases that are now commercially available, the rabbit muscle enzyme with a useful specific activity of 20 Umg-1 still remains the most cost-efficient catalyst for preparative work, although the reported higher stability of the Staphylococcus carnosus enzyme is a challenge [252,285], Literally hundreds of aldehydes have so far been tested successfully by enzymatic... 

Besides acid stability and resistance against /flactamases, the ideal antibiotic should feature broad-spectrum utility against various bacteria and effectiveness against bacterial problem strains which cannot be combated by naturally occurring antibiotics or which develop resistance, such as the problem strain in hospitals, Staphylococcus aureus. 

Catalases are mainly present in microorganisms such as Kocuria and Staphylococcus and are responsible for peroxide reduction. This reaction contributes to eolor and flavor stabilization. Nitrate reductase, also present in those microorganisms, is a very important enzyme for the reduction of nitrate to nitrite in slow ripened sausages where there is initial addition of nitrate. Recently, two strains of Lactobacillus fermentum have proved to be able to generate nitric oxide and give an acceptable color in sausages without nitrate/nitrite. This may be important in the case of cured meats with no addition of either nitrate or nitrite (Moller et al. 2003). 

In addition to enzymes, the vaginal lumen is a non-sterile area inhabited by a variety of microorganisms, mainly Lactobacillus, Bacteroides, and Staphylococcus epidermidis, as well as potentially pathogenic aerobesJ The existence of these microbes and their metabolites may also have a detrimental effect on the intravaginal stability of a vaginal drug delivery device. 

EDTA is reported to be effective as the metal ions sequester and is approved for use in the food industry as a stabilizer and antioxidant. It acts also as an inhibitor of Staphylococcus aureus by forming stable chelates in the media with multivalent cations that are essential for cell growth. The effect is largely bacteriostatic and easily reversed by releasing the complexed cations with other cations for which EDTA has higher affinity (Kraniak and Shelef, 1988). 

Crosslinked chloromethylated PS beads were reacted with hydantoin and imidazolidinone derivatives to produce functionalised beads which could be rendered biocidal by reaction with free chlorine or bromine. The biocidal efficacies of the N-chlorinated and, in one case, the N-brominated polymeric beads against Staphylococcus aureus or Escherichia coli 0157 H7 in aqueous suspension were determined. The N-halogenated polymeric beads were effective in aqueous disinfection application, requiring short contact times for inactivation of the two bacteria. The functionalised polymers could be tailored to the application, depending on whether rapid biocidal activity or long-term stability to loss of oxidative halogen was desired. 11 refs. (Pt.III, ibid, p.363-7)... 

The synthesis and biocidal efficacies of two PEG-N-halamine polymers were studied. The N-halamines were classified as dichlorohydantoins and chloroimidazolidin-4-ones, which were attached to a methoxy-PEG terminated amine. A1000 ppm solution of each N-halamine polymer was prepared in water and it was demonstrated that Staphylococcus aureus was inactivated when it was in contact with these polymeric solutions for ten minutes. The stability of these solutions was determined over prolonged periods of time, as well as the biocidal efficacies. These polymeric materials showed commercial potential as surface active biocides if the PEG moiety could be anchored to a srrrface. 22 refs. 

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