On the biosynthesis of biotin in Achromobacter IVSW a reinvestigation

[3-¹⁴C, ³⁵S]-L-cysteine was tested as precursor of biotin in Achromobacter IVSW. No significant incorporation was observed, in contradiction with the data previously reported. On the other hand, Achromobacter IVSW converts [³H, ¹⁴C]-dethiobiotin into biotin. This suggests that biotin is biosynthesized in Achromobacter according to the classical dethiobiotin pathway.     

What Do We Know About Metal Recycling Rates?

The recycling of metals is widely viewed as a fruitful sustainability strategy, but little information is available on the degree to which recycling is actually taking place. This article provides an overview on the current knowledge of recycling rates for 60 metals. We propose various recycling metrics, discuss relevant aspects of recycling processes, and present current estimates on global end‐of‐life recycling rates (EOL‐RR; i.e., the percentage of a metal in discards that is actually recycled), recycled content (RC), and old scrap ratios (OSRs; i.e., the share of old scrap in the total scrap flow). Because of increases in metal use over time and long metal in‐use lifetimes, many RC values are low and will remain so for the foreseeable future. Because of relatively low efficiencies in the collection and processing of most discarded products, inherent limitations in recycling processes, and the fact that primary material is often relatively abundant and low‐cost (which thereby keeps down the price of scrap), many EOL‐RRs are very low: Only for 18 metals (silver, aluminum, gold, cobalt, chromium, copper, iron, manganese, niobium, nickel, lead, palladium, platinum, rhenium, rhodium, tin, titanium, and zinc) is the EOL‐RR above 50% at present. Only for niobium, lead, and ruthenium is the RC above 50%, although 16 metals are in the 25% to 50% range. Thirteen metals have an OSR greater than 50%. These estimates may be used in considerations of whether recycling efficiencies can be improved; which metric could best encourage improved effectiveness in recycling; and an improved understanding of the dependence of recycling on economics, technology, and other factors.     

Transfer and expression of the cryIVB and cryIVD genes of Bacillus thuringiensis subsp. israelensis in Bacillus sphaericus 2297

Abstract The genes encoding the CryIVB and CryIVD crystal polypeptides of B. thuringiensis subsp. israelensis were cloned indepently on a stable shuttle vector, and transfered into B. sphaericus 2297. Recombinant cells expressed the B. thuringiensis toxins during sporulation and were shown to be toxic to Aedes aegypti fourth instar larvae, whereas the parental strain was not.     

Fate of biomedical research protocols and publication bias in France: retrospective cohort study

Objectives To describe the fate of protocols approved by the French research ethics committees, a national system created by the French 1988 Huriet-Sérusclat Act; to assess publication bias at a national level.Design Retrospective cohort study.Setting Representative sample of 25/48 French research ethics committees in 1994.Protocols 649 research protocols approved by committees, with follow-up information.Main outcome measures Protocols'' initial characteristics (design, study size, investigator) abstracted from committees'' archives; follow-up information (rates of initiation, completion, and publication) obtained from mailed questionnaire to principal investigators.Results Completed questionnaires were available for 649/976 (69%) protocols. Of these, 581 (90%) studies were initiated, 501/581 (86%) were completed, and 190/501 (38%) were published. Studies with confirmatory results were more likely to be published as scientific papers than were studies with inconclusive results (adjusted odds ratio 4.59, 95% confidence interval 2.21 to 9.54). Moreover, studies with confirmatory results were published more quickly than studies with inconclusive results (hazard ratio 2.48, 1.36 to 4.55).Conclusion At a national level, too many research studies are not completed, and among those completed too many are not published. We suggest capitalising on research ethics committees to register and follow all authorised research on human participants on a systematic and prospective basis.     

1H, 13C and 15N resonance assignment of phage T4 endoribonuclease RegB

RegB is involved in the control of the phage T4 life cycle. It inactivates the phage early mRNAs when their translation is no more required. We determined its structure and identified residues involved in substrate binding. For this, all backbone and 90% of side-chain resonance frequencies were assigned.     

Prise en charge des troubles de la reproduction chez l’adolescent

Adolescence is a period marked by the search for sexual identity. How do paraplegic or quadriplegic teenagers develop their sexual identity? How can the nursing team help them in this process? The authors study erection and the quality of sexual relations and then examine the problem of procreation. Early, practical information adapted to the neurological definition of the spinal cord injury is essential, with preservation of sperm prior to the development of urological and infectious complications. The authors report their experience of 24 paraplegic or tetraplegic teenagers at the CMPA in Neufmoutiers and the CECOS at Cochin Hospital in Paris.     

Gas chromatographic determination of low concentrations of benzoic acid in human plasma and urine

A method for the determination of benzoic acid down to concentrations of 10 ng/ml in plasma or urine is described. After addition of an internal standard, benzoic acid is extracted at acid pH into diethyl ether. Both compounds are derivatized with pentafluorobenzyl bromide. The derivatives are determined by gas chromatography using a ⁴³Ni electron-capture detector. Hippuric acid is hydrolysed in plasma and urine and total benzoic acid is determined by the same technique.