Effects of leucine-enkephalin and methionine-enkephalin on prolactin and gonadotropin secretion and synthesis in vitro

In vivo, Enkephalins, stimulate PRL, inhibit LH and are inactive on FSH. However, in monolayer pituitary cell cultures, PRL, LH and FSH secretions and synthesis are not modified by Met-Enk. (5 microgram/ml) or Leu-Enk. (5 and 10 microgram/ml). But the simultaneous presence of LHRH and Enk. induces an increase in LH secretion and synthesis without modifying FSH and PRL. In conclusion 1) Enk do not act by themself at the pituitary level but 2) they are able to modify the responses induced by hypothalamic hormones.     

Possible relationships between SLA and porcine reproduction

The possible influence of the pig major histocompatibility complex on reproductive traits is reviewed. Among the parameters investigated, significant associations were observed between SLA and genital tract development in males. Several SLA haplotypes affected either positively or negatively the development of testes, the epididymes and the Cowper's glands, whereas the influence of these haplotypes on androsterone tissue content was limited. The impact of the SLA complex on female reproductive performance has been more difficult to ascertain, although some results suggest that the SLA region may interfere with ovulation rates. The influence on prolificacy of SLA sharing between sires and dams was also investigated. Even if fertilization rate is not affected, embryonic mortality and preimplantation embryo development might be influenced by the pig MHC region. Although the litter size was not only marginally affected by the SLA complex, there is one case where SLA identity between the boar and several related sows led to significantly reduced litter size. In these families piglets homozygous for a particular SLA haplotype were almost absent, suggesting the existence of a recessive lethal gene linked to SLA.     

Use of very low density light fluorescence microscopy: study of real-time of the development of chromatin of unicellular mouse embryos

Video enhanced fluorescence microscopy coupled to digitized image processing was used to follow the dynamics of chromatin changes in live one cell mouse embryos. The experimentation on live material was made possible through the use of very low concentrations of the DNA specific fluorophore, Hoechst 33342, and very low irradiation intensities, which maintain a good viability of embryos.     

Challenges and promise at the interface of metaproteomics and genomics: an overview of recent progress in metaproteogenomic data analysis

Introduction: The study of microbial communities based on the combined analysis of genomic and proteomic data – called metaproteogenomics – has gained increased research attention in recent years. This relatively young field aims to elucidate the functional and taxonomic interplay of proteins in microbiomes and its implications on human health and the environment.

Areas covered: This article reviews bioinformatics methods and software tools dedicated to the analysis of data from metaproteomics and metaproteogenomics experiments. In particular, it focuses on the creation of tailored protein sequence databases, on the optimal use of database search algorithms including methods of error rate estimation, and finally on taxonomic and functional annotation of peptide and protein identifications.

Expert opinion: Recently, various promising strategies and software tools have been proposed for handling typical data analysis issues in metaproteomics. However, severe challenges remain that are highlighted and discussed in this article; these include: (i) robust false-positive assessment of peptide and protein identifications, (ii) complex protein inference against a background of highly redundant data, (iii) taxonomic and functional post-processing of identification data, and finally, (iv) the assessment and provision of metrics and tools for quantitative analysis.     

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.     

Whole genome sequencing of a natural recombinant Toxoplasma gondii strain reveals chromosome sorting and local allelic variants

Background  

Toxoplasma gondii is a zoonotic parasite of global importance. In common with many protozoan parasites it has the capacity for sexual recombination, but current evidence suggests this is rarely employed. The global population structure is dominated by a small number of clonal genotypes, which exhibit biallelic variation and limited intralineage divergence. Little is known of the genotypes present in Africa despite the importance of AIDS-associated toxoplasmosis.