Outbreak of gastroenteritis caused by the pandemic Vibrio parahaemolyticus O3:K6 in Mexico

During 2003 and during late September of 2004, more than 1230 cases of gastroenteritis were reported in the south of Sinaloa State, north-western Mexico. All cases were attributed to the consumption of raw or undercooked shrimp collected at the Huizache-Caimanero lagunary system. Vibrio parahaemolyticus was identified by standard biochemical methods, and many strains were positive for PCR amplifications of the tlh and tdh genes and negative for the trh gene. A representative strain belonged to the O3:K6 serogroup. This is the first outbreak of gastroenteritis caused by the pandemic strains of O3:K6 V. parahaemolyticus in México.     

Polypseudorotaxanes of pegylated insulin with cyclodextrins: application to sustained release system

The monosubstituted insulin with poly(ethylene glycol) (PEG, MW about 2200) formed polypseudorotaxanes with alpha- and gamma-cyclodextrins (CyDs), by inserting one PEG chain of the pegylated insulin in the alpha-CyD cavity and two PEG chains in the gamma-CyD cavity. The pegylated insulin/alpha- and gamma-CyD polypseudorotaxanes were less soluble in water and the release rate of the drug decreased in the order of drug alone > the gamma-CyD polypseudorotaxane > the alpha-CyD polypseudorotaxane. The subcutaneous administration of the pegylated insulin/gamma-CyD polypseudorotaxane in rats significantly sustained plasma glucose levels with an enhanced hypoglycemic effect. The results indicated that the pegylated insulin/CyD polypseudorotaxanes can work as a sustained drug release system and the polypseudorotaxane formation may be useful as a sustained drug delivery technique for pegylated proteins and peptides.     

Changes in protein phosphorylation in guinea pig polymorphonuclear leukocytes by treatment with membrane-perturbing agents which stimulate superoxide anion production

Phosphorylation of proteins was examined in guinea pig polymorphonuclear leukocytes in relation to the effects of membrane-perturbing agents, which stimulate superoxide anion production, and their inhibitors. The phosphorylation was detected by 32P autoradiography after separation by two-dimensional electrophoresis of proteins phosphorylated in 32P-preloaded cells. Though phosphorylation of various proteins was stimulated by each of the membrane-perturbing agents, the stimulation was especially marked in six proteins. Phorbol myristate acetate and digitonin enhanced the phosphorylation of the six proteins, while myristate and concanavalin A increased the phosphorylation of five and three proteins, respectively, out of the six proteins. p-Bromophenacyl bromide, an inhibitor of phospholipase A2, inhibited the stimulatory effect of phorbol myristate acetate on both superoxide anion production and protein phosphorylation. Trifluoperazine, a calmodulin inhibitor, also inhibited the effect of phorbol myristate acetate on both, except for an increase in the phosphorylation of one out of the six proteins. alpha-Methylmannoside, an inhibitor of concanavalin A binding, inhibited the stimulation of the phosphorylation of the three proteins by concanavalin A. The results indicate that the activation of superoxide anion production by the membrane-perturbing agents in guinea pig polymorphonuclear leukocytes is accompanied by the phosphorylation of, at least some of, these six proteins.     

Serum stability of selected decapeptide agonists of KISS1R using pseudopeptides

Metastin/kisspeptin, a 54-amino acid peptide, is the ligand of the G-protein-coupled receptor KISS1R which plays a key role in pathways that regulate reproduction and cell migration in many endocrine and gonadal tissues. The N-terminally truncated decapeptide, metastin(45–54), has 3–10 times higher receptor affinity and intracellular calcium ion-mobilizing activity but is rapidly inactivated in serum. In this study we designed and synthesized stable KISS1R agonistic decapeptide analogs with selected substitutions at positions 47, 50, and 51. Replacement of glycine with azaglycine (azaGly) in which the α-carbon is replaced with a nitrogen atom at position 51 improved the stability of amide bonds between Phe⁵⁰-Gly⁵¹ and Gly⁵¹-Leu⁵² as determined by in vitro mouse serum stability studies. Substitution for tryptophan at position 47 with other amino acids such as serine, threonine, β-(3-pyridyl)alanine, and d-tryptophan (d-Trp), produced analogs that were highly stable in mouse serum. d-Trp⁴⁷ analog 13 showed not only high metabolic stability but also excellent KISS1R agonistic activity. Other labile peptides may have increased serum stability using amino acid substitution.     

Purification and characterization of multiple bacteriocins and an inducing peptide produced by Enterococcus faecium NKR-5-3 from Thai fermented fish

Enterocins NKR-5-3A, B, C, and D were purified from the culture supernatant of Enterococcus faecium NKR-5-3 and characterized. Among the four purified peptides, enterocin NKR-5-3A (5242.3 Da) was identical to brochocin A, produced by Brochothrix campestris ATCC 43754, in mature peptides, and its putative synergistic peptide, enterocin NKR-5-3Z, was found to be encoded in ent53Z downstream of ent53A, encoding enterocin NKR-5-3A. Enterocin NKR-5-3B (6316.4 Da) showed a broad antimicrobial spectrum, and enterocin NKR-5-3C (4512.8 Da) showed high activity against Listeria. Enterocin NKR-5-3D (2843.5 Da), showing high homology to an inducing peptide produced by Lactobacillus sakei 5, induced the production of the enterocins. The enterocins showed different antimicrobial spectra and intensities. E. faecium NKR-5-3 concomitantly produced enterocins NKR-5-3A, B, C, and D which probably belong to different classes of bacteriocins. Furthermore, NKR-5-3 production was induced by enterocin NKR-5-3D.