Spring Time and Autumn Time Toxic Effects of Copper (II), 3-(2-Furyl) Prop-2-Enal Semicarbazone and [CuCl2(FASC)2] Complex in Mice

In vitro, 3-(2-furyl) prop-2-enal semicarbazone-copper (II) complex [CuCl₂(FASC)₂] presents antimitotic effects. In this work we studied the in vivo seasonal toxic effects in male Swiss mice of CuCl₂, and FASC and the [CuCl₂(FASC)₂] complex. In spring, one injection of CuCl₂8.10^-2 mmol killed 16% of animals after 24 h. Cupric chloride lethal dose was up to 64.10^-2 mmol with 100% mice dead after 24 h. FASC was well tolerated from 0.65 to 1.3 mmol. The complex was 100% lethal with 48.10^-2 mmol. In autumn, mice were more sensitive to CuCl₂ and to the complex with lethal doses up to 32.10^-2 mmol and 8.10^-2 mmol, respectively. On the other hand, FASC was well tolerated. It is concluded that the in vivo toxic effects of CuCl₂ and [CuCl₂(FASC)₂] complex are quite different in spring and autumn.     

Nucleic acid testing (NAT) in high prevalence–low resource settings

Blood screening by NAT for major transfusion transmitted viral infections (TTIs) was originally intended to complement serology for detection of infected donations. Reports from developed countries showed limited marginal value to NAT blood screening in improving blood safety. Reports on NAT results from Europe indicated yield of 1:0.6 million donations for HBV, <1:M for HCV and HIV-1-related to low prevalence of TTI. In contrast, prevalence of TTI in resource-limited countries is almost always high. As a result, more incident cases can be expected among first-time blood donors. Most reports of NAT blood donation screening in these countries showed NAT confirmed yield as high as 1/2800 for HBV and 1/3100 blood donations for HCV as reported from Thailand and Egypt, respectively. The issues for low resource countries are mostly the high cost of NAT but also the requirements of staff qualification, adequate facilities, reagent procurement and maintenance of delicate equipment. Alternatives to commercial NAT are the use of combos antigen-antibody for HIV and HCV, anti-HBc for HBV and in-house NAT. Most of these alternatives have been reported but very few comparisons are available. Once yield data is available, models for estimation of feasibility and cost-effectiveness are proposed to help decision-making.     

Merino sheep: a further look at quantitative trait loci for wool production

A quantitative trait loci (QTL) analysis of wool traits from experimental half-sib data of Merino sheep is presented. A total of 617 animals distributed in 10 families were genotyped for 36 microsatellite markers on four ovine chromosomes OAR1, OAR3, OAR4 and OAR11. The markers covering OAR3 and OAR11 were densely spaced, at an average distance of 2.8 and 1.2 cM, respectively. Body weight and wool traits were measured at first and second shearing. Analyses were conducted under three hypotheses: (i) a single QTL controlling a single trait (for multimarker regression models); (ii) two linked QTLs controlling a single trait (using maximum likelihood techniques) and (iii) a single QTL controlling more than one trait (also using maximum likelihood techniques). One QTL was identified for several wool traits on OAR1 (average curvature of fibre at first and second shearing, and clean wool yield measured at second shearing) and on OAR11 (weight and staple strength at first shearing, and coefficient of variation of fibre diameter at second shearing). In addition, one QTL was detected on OAR4 affecting weight measured at second shearing. The results of the single trait method and the two-QTL hypotheses showed an additional QTL segregating on OAR11 (for greasy fleece weight at first shearing and clean wool yield trait at second shearing). Pleiotropic QTLs (controlling more than one trait) were found on OAR1 (clean wool yield, average curvature of fibre, clean and greasy fleece weightand staple length, all measured at second shearing).     

Adaptation of acidogenic sludge to increasing glycerol concentrations for biohydrogen production

Hydrogen is a promising alternative as an energetic carrier and its production by dark fermentation from wastewater has been recently proposed, with special attention to crude glycerol as potential substrate. In this study, two different feeding strategies were evaluated for replacing the glucose substrate by glycerol substrate: a one-step strategy (glucose was replaced abruptly by glycerol) and a step-by-step strategy (progressive decrease of glucose concentration and increase of glycerol concentration from 0 to 5 g L^?1), in a continuous stirred tank reactor (12 h of hydraulic retention time (HRT), pH 5.5, 35 °C). While the one-step strategy led to biomass washout and unsuccessful H₂ production, the step-by-step strategy was efficient for biomass adaptation, reaching acceptable hydrogen yields (0.4?±?0.1 mol_H2?mol^?1 _{glycerol consumed}) around 33 % of the theoretical yield independently of the glycerol concentration. Microbial community structure was investigated by single-strand conformation polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE) fingerprinting techniques, targeting either the total community (16S ribosomal RNA (rRNA) gene) or the functional Clostridium population involved in H₂ production (hydA gene), as well as by 454 pyrosequencing of the total community. Multivariate analysis of fingerprinting and pyrosequencing results revealed the influence of the feeding strategy on the bacterial community structure and suggested the progressive structural adaptation of the community to increasing glycerol concentrations, through the emergence and selection of specific species, highly correlated to environmental parameters. Particularly, this work highlighted an interesting shift of dominant community members (putatively responsible of hydrogen production in the continuous stirred tank reactor (CSTR)) according to the gradient of glycerol proportion in the feed, from the family Veillonellaceae to the genera Prevotella and Clostridium sp., putatively responsible of hydrogen production in the CSTR.     

Isolation and characterization of novel bacterial strains exhibiting ligninolytic potential

Background

The number of biotransformations that use nicotinamide recycling systems is exponentially growing. For this reason one of the current challenges in biocatalysis is to develop and optimize more simple and efficient cofactor recycling systems. One promising approach to regenerate NAD⁺ pools is the use of NADH-oxidases that reduce oxygen to hydrogen peroxide while oxidizing NADH to NAD⁺. This class of enzymes may be applied to asymmetric reduction of prochiral substrates in order to obtain enantiopure compounds.

Results

The NADH-oxidase (NOX) presented here is a flavoenzyme which needs exogenous FAD or FMN to reach its maximum velocity. Interestingly, this enzyme is 6-fold hyperactivated by incubation at high temperatures (80°C) under limiting concentrations of flavin cofactor, a change that remains stable even at low temperatures (37°C). The hyperactivated form presented a high specific activity (37.5 U/mg) at low temperatures despite isolation from a thermophile source. Immobilization of NOX onto agarose activated with glyoxyl groups yielded the most stable enzyme preparation (6-fold more stable than the hyperactivated soluble enzyme). The immobilized derivative was able to be reactivated under physiological conditions after inactivation by high solvent concentrations. The inactivation/reactivation cycle could be repeated at least three times, recovering full NOX activity in all cases after the reactivation step. This immobilized catalyst is presented as a recycling partner for a thermophile alcohol dehydrogenase in order to perform the kinetic resolution secondary alcohols.

Conclusion

We have designed, developed and characterized a heterogeneous and robust biocatalyst which has been used as recycling partner in the kinetic resolution of rac-1-phenylethanol. The high stability along with its capability to be reactivated makes this biocatalyst highly re-useable for cofactor recycling in redox biotransformations.     

A deletion in exon 9 of the LIPH gene is responsible for the rex hair coat phenotype in rabbits (Oryctolagus cuniculus)

The fur of common rabbits is constituted of 3 types of hair differing in length and diameter while that of rex animals is essentially made up of amazingly soft down-hair. Rex short hair coat phenotypes in rabbits were shown to be controlled by three distinct loci. We focused on the "r1" mutation which segregates at a simple autosomal-recessive locus in our rabbit strains. A positional candidate gene approach was used to identify the rex gene and the corresponding mutation. The gene was primo-localized within a 40 cM region on rabbit chromosome 14 by genome scanning families of 187 rabbits in an experimental mating scheme. Then, fine mapping refined the region to 0.5 cM (Z = 78) by genotyping an additional 359 offspring for 94 microsatellites present or newly generated within the first defined interval. Comparative mapping pointed out a candidate gene in this 700 kb region, namely LIPH (Lipase Member H). In humans, several mutations in this major gene cause alopecia, hair loss phenotypes. The rabbit gene structure was established and a deletion of a single nucleotide was found in LIPH exon 9 of rex rabbits (1362delA). This mutation results in a frameshift and introduces a premature stop codon potentially shortening the protein by 19 amino acids. The association between this deletion and the rex phenotype was complete, as determined by its presence in our rabbit families and among a panel of 60 rex and its absence in all 60 non-rex rabbits. This strongly suggests that this deletion, in a homozygous state, is responsible for the rex phenotype in rabbits.