Pulmonary nosocomial infection.

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Recent studies described several different routes that facilitate nitrogen-nitrogen bond formation in natural product biosynthesis. We report herein the identification of unprecedented machinery for hydrazine formation involved in the biosynthesis of s56-p1, a dipeptide natural product with a unique hydrazone unit. The gene cassette comprising this machinery is widespread across several bacterial phyla, highlighting the overlooked potential of bacteria to synthesize hydrazine.

Enzymatic removal of various phenol compounds from artificial wastewater was undertaken by the combined use of mushroom tyrosinase (EC 1.14.18.1) and chitosan beads as function of pH value, temperature, tyrosinase dose, and hydrogen peroxide-to-substrate ratio. Chitosan film incubated in a p-crersol+tyrosinase mixture had the main peaks at 400-470 nm assigned to chemically adsorbed quinone derivatives, which increased over the immersion time. These results indicate that removal of phenol compounds is caused by their tyrosinase-catalyzed oxidation to the corresponding quinone derivatives and the subsequent chemical adsorption on the chitosan film. The optimum conditions for quinone adsorption were determined to be pH 7 and 45 degrees C for p-cresol. Some alkyl-substituted phenol compounds were removed by adsorption of quinone derivatives enzymatically generated on the chitosan beads, and the % removal for p-cresol, 4-ethylphenol, 4-n-propylphenol, 4-n-butylphenol, and p-chlorophenol went up to 93%. In addition, 4-tert-butylphenol underwent tyrosinase-catalyzed oxidation in the presence of hydrogen peroxide. This procedure was applicable to removal of chlorophenols and alkyl-substituted phenols.

Natural-abundance carbon-I 3 n.m.r. spectra of all the glucobioses and of four selected glucotrioses in aqueous solution have been measured and are discussed. Peak assignments were made on the basis of comparison with the spectra of methyl glucopyranosides, four mono-0-methylglucoses and five methyl glucobiosides. Carbon-I 3 n.m.r. spectroscopy proved to be a useful tool for stereochemical characterisation of these oligosaccharides. In addition, carbon-I 3 n.m.r. spectra of the a-limit dextrins from glycogen and amylopectin have been measured and the differences between them are discussed.SPECTROMETRIC methods (i.r.,l o.r.d.,2 and lH n.m.r.3~4) have been used for establishing the configuration of glycosidic linkages of oligosaccharides and polysaccharides. The Karplus equation in lH n.m.r. has been applied extensively in the structural studies of monosaccharide pyranose and furanose derivatives.5 Positions of linkage in oligosaccharides have been determined by chemical methods and by biochemical degradation.+lO Recently, the 13C n.m.r. spectra of monosaccharides 11,12 and some common oligosaccharides 13*14 have been published and interpreted. These reports show that 13C chemical shift differences in sugars could be explained in terms of steric hindrance and proximity effectsWe have already reported that 13C n.m.r. spectroscopy can be used for the determination of the anomeric configurations of glucobi~ses.~~ We now describe the application of 13C n.m.r. to the configurational and conformational analysis of glucose oligomers and polymers, as well as to the determination of their linkage positions. Some tentative assignments l5 arc corrected on the basis of further data reported here. RESULTS AND DISCUSSIONIn 13C n.m.r. spectroscopy, it is difficult and laborious t o give a full peak assignment of sugar carbon atoms, although information from previous work has made it considerably ~imp1er.ll-l~ Roberts and his co-workers l1 showed that (a) methylation of a hydroxy-group effects

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It has been widely accepted that cytokines play important roles in the development of organ failure in various pathophysiological conditions of critically ill patients. Various new technologies, including continuous renal replacement therapy, have been developed for the removal of causative humoral mediators in sepsis or other critical conditions. Nonselective blood purification technologies, such as hemofiltration and plasma exchange, are applied in cytokine removal technology. However, the more selective blood purification technologies, such as ad-sorption, and the combination of those technologies, should be considered in future applications. Only through a prospective randomized controlled study can it be elucidated whether or not these technologies have efficacy in the treatment of sepsis and critically ill patients with hypercytokinemia. We should join and discuss the design of future clinical trials with a standardized strategy for the evaluation of the technologies.

Amino-group carrier proteins (AmCPs) mediate the biosynthesis of lysine and arginine in some bacteria and archaea. Here we demonstrate that an uncharacterized AmCP-mediated biosynthetic system functions to biosynthesize the previously uncharacterized and nonproteinogenic amino acid (2S,6R)-diamino-(5R,7)-dihydroxy-heptanoic acid (DADH) in Streptomyces sp. SANK 60404. DADH is incorporated into a novel peptide metabolite, vazabitide A, featuring an azabicyclo-ring structure, by nonribosomal peptide synthetases and successive modification enzymes in this bacterium. As the AmCP-mediated machinery for DADH biosynthesis is widely distributed in bacteria, further analysis of uncharacterized AmCP-containing gene clusters will lead to the discovery of novel bioactive compounds and novel biosynthetic enzymes.