Repeated use of Bacillus subtilis cell walls for copper binding

Purified cell walls from Bacillus subtilis were repeatedly suspended in 5 mm CuCl₂ and, after removing unbound Cu, were suspended in 1% (v/v) HNO₃ to release bound Cu. The walls were then regenerated by washing in H₂O. After five cycles, copper binding actually increased slightly, probably due to enhanced exposure of binding sites in the walls. Thus bacterial walls may be used repeatedly for metal removal during bioremediation of heavy metal pollution.R.J.C. McLean is with the Department of Biology, Southwest Texas State University, 601 University Drive, San Marcos, TX 78666-4616, USA A.M. Campbell is with the Department of Chemical Engineering, Queen's University, Kingston, Ontario, K7L 3N6, Canada. P.T. Khu is with the Department of Mining Engineering, Queen's University, Kingston, Ontario, K7L 3N6, Canada. A.T. Persaud, L.E. Bickerton and D. Beauchemin are with the Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada.     

D-Mannitol oxidation in the land snail, Helix aspersa

Respiration by mitochondrial preparations from hepatopancreas tissue of the land snail Helix aspersa is stimulated by D-mannitol. The rate of mannitol-stimulated respiration is approximately one-half that given by succinate, the most effective substrate thus far tested with these preparations. Mannitol-stimulated respiration is cyanide-insensitive but is not inhibited by salicylhydroxamate. The product of the membrane-bound mannitol-oxidizing activity was shown to be D-mannose by thin layer chromatography, high voltage electrophoresis of the germanate and borate complexes, gas chromatography of the trimethylsilyl derivative, low resolution mass spectrometry of the trimethylsilyl derivative, and by an enzymatic method dependent upon phosphomannose isomerase. The reaction mannitol + O2 leads to mannose is stoichiometric; however, it is not known whether O2 is the immediate electron acceptor. The activity in Helix mitochondria is thus unique among most alditol-oxidizing enzymes in not being pyridine nucleotide linked and in acting on carbon 1 rather than carbon 2.     

Opiate receptor blockade in man reduces 2-deoxy-d-glucose-induced food intake but not hunger,thirst, and hypothermia

Opioid peptides may act as neuromodulators in the central nervous system to conserve energy stores and water in mammals. To examine this hypothesis in man, the effect of opiate receptor blockade with naloxone on the hunger, thirst, and hypothermic response to 2-deoxy-D-glucose-induced glucoprivic stress was assessed. Opiate receptor blockade decreased stress-induced food intake but did not reduce marked increases in hunger produced by glucoprivation. Naloxone infusions did not change the hypercortisolemic, polydipsic, hypothermic, and thermogenic response to 2-deoxy-D-glucose. While these results do not suggest a major role for a β-endorphin modulation of stress-induced hunger, hypothermia and water conservation, the reduction of food intake could be due to augmented satiety, perhaps associated with retardation of gastric emptying during opiate receptor blockade.     

Hepatitis C Virus Phylogenetic Clustering Is Associated with the Social-Injecting Network in a Cohort of People Who Inject Drugs

It is hypothesized that social networks facilitate transmission of the hepatitis C virus (HCV). We tested for association between HCV phylogeny and reported injecting relationships using longitudinal data from a social network design study. People who inject drugs were recruited from street drug markets in Melbourne, Australia. Interviews and blood tests took place three monthly (during 2005–2008), with participants asked to nominate up to five injecting partners at each interview. The HCV core region of individual isolates was then sequenced and phylogenetic trees were constructed. Genetic clusters were identified using bootstrapping (cut-off: 70%). An adjusted Jaccard similarity coefficient was used to measure the association between the reported injecting relationships and relationships defined by clustering in the phylogenetic analysis (statistical significance assessed using the quadratic assignment procedure). 402 participants consented to participate; 244 HCV infections were observed in 238 individuals. 26 genetic clusters were identified, with 2–7 infections per cluster. Newly acquired infection (AOR = 2.03, 95% CI: 1.04–3.96, p = 0.037, and HCV genotype 3 (vs. genotype 1, AOR = 2.72, 95% CI: 1.48–4.99) were independent predictors of being in a cluster. 54% of participants whose infections were part of a cluster in the phylogenetic analysis reported injecting with at least one other participant in that cluster during the study. Overall, 16% of participants who were infected at study entry and 40% of participants with newly acquired infections had molecular evidence of related infections with at least one injecting partner. Likely transmission clusters identified in phylogenetic analysis correlated with reported injecting relationships (adjusted Jaccard coefficient: 0.300; p<0.001). This is the first study to show that HCV phylogeny is associated with the injecting network, highlighting the importance of the injecting network in HCV transmission.