Characterization of mono- and mixed-culture Campylobacter jejuni biofilms

Campylobacter jejuni, one of the most common causes of human gastroenteritis, is a thermophilic and microaerophilic bacterium. These characteristics make it a fastidious organism, which limits its ability to survive outside animal hosts. Nevertheless, C. jejuni can be transmitted to both humans and animals via environmental pathways, especially through contaminated water. Biofilms may play a crucial role in the survival of the bacterium under unfavorable environmental conditions. The goal of this study was to investigate survival strategies of C. jejuni in mono- and mixed-culture biofilms. We grew monoculture biofilms of C. jejuni and mixed-culture biofilms of C. jejuni with Pseudomonas aeruginosa. We found that mono- and mixed-culture biofilms had significantly different structures and activities. Monoculture C. jejuni biofilms did not consume a measurable quantity of oxygen. Using a confocal laser scanning microscope (CLSM), we found that cells from monoculture biofilms were alive according to live/dead staining but that these cells were not culturable. In contrast, in mixed-culture biofilms, C. jejuni remained in a culturable physiological state. Monoculture C. jejuni biofilms could persist under lower flow rates (0.75 ml/min) but were unable to persist at higher flow rates (1 to 2.5 ml/min). In sharp contrast, mixed-culture biofilms were more robust and were unaffected by higher flow rates (2.5 ml/min). Our results indicate that biofilms provide an environmental refuge that is conducive to the survival of C. jejuni.     

Pathways of glyceride glycerol synthesis

Isolated rat liver parenchymal cells were incubated for various periods with [U-(14)C,2-(3)H]glycerol and the radioisotopic yields in the major products were determined, as well as the (3)H/(14)C ratios in glyceride glycerol and intracellular glycerol phosphate. Under the conditions used (0.1mm-glycerol+10mm-l-lactate or 10mm-glycerol as substrates), only small differences were found between these (3)H/(14)C ratios. The results suggest a minor role for a pathway of glyceride glycerol synthesis involving reduction of acylated dihydroxyacetone phosphate, under these experimental conditions.     

Lipase-catalyzed synthesis of glycerol carbonate from renewable glycerol and dimethyl carbonate through transesterification

Glycerol carbonate is a key multifunctional compound employed as solvent, additive, monomer, and chemical intermediate. Enzymatic synthesis of glycerol carbonate from renewable starting materials (glycerol and dimethyl carbonate) was successfully achieved by immobilized lipase from Candida antarctica (CALB, Novozym 435). Addition of molecular sieves as scavenger for the removal of methanol, which was generated from dimethyl carbonate during the reaction, accelerated a reaction rate. After the optimization, the equimolar use of glycerol and dimethyl carbonate in the Novozym 435-catalyzed reaction yielded a glycerol carbonate with almost quantitative yield. The resulting glycerol carbonate from 60 °C reaction has shown the low enantiomeric excess (13% ee) as configuration of (R)-enantiomer.     

A one pot synthesis of mono- and di-lactosyl sphingosines

The importance of analogues of lactosyl ceramides as basic structures of many natural glycosphingolipids provided a rationale for developing an efficient synthetic route to these compounds. We report herein a novel approach to synthesize several members of this family. Glycosylation of N-diphenylmethylene-spingosine, which exists in an imine–oxazolidine tautomeric mixture, with acetobromolactose under a modified Koenigs-Knorr condition yielded lactosyl -(1 1) sphingosine, lactosyl -(1 3) sphingosine and dilactosyl sphingosine in good yields. A similar glycosylation could be applicable to the synthesis of other glycosphingolipids.     

Comparative study of neurophysiological effects of unsubstituted phenol ethers of alpha mono- and diglycerides]

The addition of a second alpha-glyceryl to alpha-phenoxypropanediol strongly modifies the inhibitor actions on the synaptic transmission. These new di-ethers do not show solubility nor effect on the water superficial tension and simultaneously do not provoke any neurophysiological inhibitor effect. The ability of cellular penetration by lipidic solubility seems a necessary condition for pharmacological effect of alpha-glyceric ethers.     

The synthesis of cholesteryl alkyl ethers

Seventeen cholesteryl alkyl ethers were synthesized through alcoholysis of cholesterol p-toluenesulfonate. This method was found superior to the etherification of sodium or potassium cholesterylate with alkyl halides or methanesulfonates, especially for the preparation of long-chain unsaturated alkyl ethers of [7(n)-³H]cholesterol of high specific activity.     

Characterization of glycerol nonutilizing and protoperithecial mutants ofNeurospora

Summary Mutants defective in polyol metabolism and/or in protoperithecial development were selected inNeurospora tetrasperma, a species in which protoperithecial development occurs at nonpermissively high temperature if certain polyols are used in lieu of sucrose as carbon source. Mutants selected for nonutilization of one of the four polyols tested, glycerol, mannitol, sorbitol, or xylitol, were usually found to be nonutilizers of the other three polyols as well. Mutants blocked at various stages of protoperithecial development complemented pairwise to produce more advanced developmental stages, usually mature protoperithecia and, when of opposite mating type, mature perithecia. About one-third of the mutants manifested both polyol auxotrophy and defective protoperithecial development upon initial isolation, but protoperithecial defectiveness in such mutants usually showed erratic segregation in crosses and/or instability to repeated vegetative transfer, whereas polyol auxotrophy usually did not and was, therefore, studied further. Two glycerol nonutilizing strains were introgressed intoN. crassa to facilitate genetic analysis. One,glp-4, lacked both inducible and constitutive glycerol kinase and mapped to linkage group VI, betweenad-1 andrib-1; the other,glp-5, lacked glyceraldehyde kinase and mapped to linkage group I, proximal toad-9. Another mutant,gly-u(234), has been reported by other investigators to lack inducible glycerol kinase but to map to linkage group I, distal toad-9.     

Acrolein synthesis from glycerol in hot-compressed water

Glycerol conversion was conducted in hot-compressed water (HCW: 573-673 K, 25-34.5 MPa) using a batch and a flow apparatus and the influences of temperature, H(2)SO(4), glycerol concentration, and pressure, were examined. The yield of acrolein was enhanced by higher glycerol and H(2)SO(4) concentration, and higher pressure. Approximately 80% selectivity of acrolein was obtained at 90% of glycerol conversion with an acid catalyst in supercritical condition (673 K and 34.5 MPa). The rate constant of acrolein decomposition was always higher than that of acrolein formation in the absence of acid catalyst but the rate constant of acrolein formation could be overcome that of acrolein decomposition by addition acid in supercritical condition.