Effect of the luteinizing hormone on embryo production in superovulated rabbit does

For most domestic animals, the responses to superovulation treatments are not controlled as a consequence of the lack of knowledge on exogenous gonadotrophins effects on the ovarian function. The role of luteinizing hormone (LH) on the number and quality of embryos produced was evaluated on rabbit does superovulated with porcine FSH (pFSH). Parameters of embryos recovery, in vitro and in vivo embryo development rates after freezing/thawing were compared. We used three experimental groups: (1) control group without superovulation treatment, (2) "pFSH+pLH" and (3) "pFSH" groups where females were treated with pFSH, respectively, with (20%) or without (0%) porcine LH supplementation. The number of corpora lutea and the number of embryos produced were significantly higher (p<0.001) in superovulated does than in control group (27.1, 26.7 versus 11.9 corpora lutea and 20.3, 21.2 versus 9.6 embryos produced for pFSH+pLH, pFSH and control group, respectively). However, both gonadotrophins administrations (groups 2 and 3) led to defaults of ovulation when compared with untreated does. No significant difference was observed between the number and quality of the embryos produced by does treated with pFSH+pLH or with pFSH alone. Moreover, we observed no significant difference between results of in vivo and in vitro viability assays after thawing. We concluded that pFSH alone seems to be sufficient to stimulate the follicles growth and that exogenous pLH administrated has no effect on the quantity and quality of embryos. Further studies are needed to evaluate the hormonal patterns before and after the gonadotrophins injections in the rabbit species.     

Conformationally restricted homotryptamines 3. Indole tetrahydropyridines and cyclohexenylamines as selective serotonin reuptake inhibitors

A series of indole tetrahydropyridine and indole cyclohexenylamines was prepared, and their binding affinities at the human serotonin transporter (SERT) were determined. In particular, a nitrile substituent at the C5 position of the indole ring gave potent SERT activity. The stereochemistry of the N,N-dimethylamine substituent was determined for the most potent indole cyclohexenylamine, 6a. The enantiomers of 6a were energy minimized and compared to other conformationally restricted SSRIs. Compound 6a was found to give a dose-response similar to the SSRI fluoxetine in microdialysis studies in rats.     

Atg1 allows second-signaled autophagic cell death in Dictyostelium

We investigated the role of Atg1 in autophagic cell death (ACD) in a Dictyostelium monolayer model. The model is especially propitious, not only because of genetic tractability and absence of apoptosis machinery, but also because induction of ACD requires two successive exogenous signals, first the combination of starvation and cAMP, second the differentiation factor DIF-1. This enables one to analyze separately first-signal-induced autophagy and subsequent second-signal-induced ACD. We used mutants of atg1, a gene that plays an essential role in the initiation of autophagy. Upon starvation/cAMP, in contrast to parental cells, atg1 mutant cells showed irreversible lesions, clearly establishing a protective role for Atg1. Upon subsequent exposure to DIF-1 or to more ACD-specific second signals, starved parental cells progressed to ACD, but starved atg1 mutant cells did not, showing that Atg1 was required for ACD. Thus, in the same cells Atg1 was required in two apparently opposite ways, upon first-signaling for cell survival and upon second-signaling for ACD. Our findings strongly suggest that Atg1, thus presumably autophagy, protects the cells from starvation-induced cell death, allowing subsequent induction of ACD by the second signal. ACD is therefore not only "with" autophagy (since it showed signs of autophagy throughout), but is also "allowed by" autophagy. This does not exclude a role for autophagy also after second signaling. These results may account for discrepancies reported in the literature, encourage searches for second signals in different developmental models of ACD, and incite caution in autophagy-related therapeutic attempts.     

R5-SHIV induces multiple defects in T cell function during early infection of rhesus macaques including accumulation of T reg cells in lymph nodes

Background

HIV-1 is a pathogen that T cell responses fail to control. HIV-1gp120 is the surface viral envelope glycoprotein that interacts with CD4 T cells and mediates entry. HIV-1gp120 has been implicated in immune dysregulatory functions that may limit anti-HIV antigen-specific T cell responses. We hypothesized that in the context of early SHIV infection, immune dysregulation of antigen-specific T-effector cell and regulatory functions would be detectable and that these would be associated or correlated with measurable concentrations of HIV-1gp120 in lymphoid tissues.

Methods

Rhesus macaques were intravaginally inoculated with a Clade C CCR5-tropic simian-human immunodeficiency virus, SHIV-1157ipd3N4. HIV-1gp120 levels, antigen-specificity, levels of apoptosis/anergy and frequency and function of Tregs were examined in lymph node and blood derived T cells at 5 and 12 weeks post inoculation.

Results/Conclusions

We observed reduced responses to Gag in CD4 and gp120 in CD8 lymph node-derived T cells compared to the peripheral blood at 5 weeks post-inoculation. Reduced antigen-specific responses were associated with higher levels of PD-1 on lymph node-derived CD4 T cells as compared to peripheral blood and uninfected lymph node-derived CD4 T cells. Lymph nodes contained increased numbers of Tregs as compared to peripheral blood, which positively correlated with gp120 levels; T regulatory cell depletion restored CD8 T cell responses to Gag but not to gp120. HIV gp120 was also able to induce T regulatory cell chemotaxis in a dose-dependent, CCR5-mediated manner. These studies contribute to our broader understanding of the ways in which HIV-1 dysregulates T cell function and localization during early infection.     

The phylogenetic tree gathering the plant Zn/Cd/Pb/Co P1B-ATPases appears to be structured according to the botanical families

Plant Zn/Cd/Pb/Co P_1B-ATPases (HMAs) play different roles, among which are the control of metal transport from the roots to the shoot and/or from the cytoplasm into the cell vacuole. Transferring the knowledge acquired on HMAs from model species to HMAs from other species requires one to identify orthologues in these other species. Through an extensive screening of the public sequence databases, 96 plant P_1B-ATPases showing orthology to any of the AtHMA1, AtHMA2, AtHMA3 or AtHMA4 isoforms were identified from 32 plant species belonging to 15 botanical families. The number of paralogues within a species varied greatly from species to species, even within a specific botanical family, suggesting that gene duplication events occurred after speciation. The phylogenetic tree gathering the Zn/Cd/Pb/Co P_1B-ATPases was strongly structured according to the botanical family to which the sequences could be related to. In particular, no strict orthology relationship links the Brassicaceae HMAs to the non-Brassicaceae or the Poaceae ones. Recent data showed that the sole rice HMA characterised to date displays different functional properties from the Arabidopsis HMAs. Altogether, data suggest that it might be risky to directly transfer the knowledge acquired through the study of HMAs in model plant species to HMAs from other species.     

Interspecific hybridization in oysters: Restriction Enzyme Digestion Chromosome Banding confirms Crassostrea angulata × Crassostrea gigas F1 hybrids

The taxonomic status of the two commercially important cupped oysters, Crassostrea angulata, the Portuguese oyster (Lamarck, 1819) and Crassostrea gigas, the Japanese oyster (Thunberg, 1793) has long been in question. The recent observation of the hybridization between C. gigas and C. angulata and the production of fertile F1s led us to search for cytogenetic evidence of both parental genomes in the interspecific hybrids. The cytogenetic characterization of the hybrids was performed by the use of restriction endonuclease treatments. This technique has recently shown the potential for individual chromosome identification by banding in oysters. Chromosomes of C. gigas, C. angulata and their hybrids were treated with two different restriction enzymes (ApaI and HaeIII), stained with Giemsa, and examined for banding patterns. These chromosome markers allowed the parental haploid sets to be identified in the hybrids. The analysis of the banded karyotypes of the interspecific hybrids showed that for each chromosome pair, one of the homologues presented a banding pattern consistent with that of C. gigas and the other homologue presented a banding pattern consistent with that of C. angulata. These cytogenetic results substantiate the reported interspecific hybridization between C. gigas and C. angulata. In view of these results and taking into account the present expansion of C. gigas aquaculture in southern Europe, the question of the need for preservation of pure C. angulata stocks should be raised as only a few populations remain in the south of Spain and Portugal. Recently, changes in the genetic composition of populations in southern Portugal have indeed been observed, showing that human activities have created contact zones between the two taxa while no natural sympatric zones exist in Europe.     

Epigenetic heredity in mice: involvement of RNA and miRNas.

By contrast with a wide definition of the 'epigenetic variation', including all changes in gene expression that do not result from alteration of the gene structure, a more restricted class had been defined, initially in plants, under the name 'paramutation'. It corresponds to epigenetic modifications distinct from the regulatory interactions of the cell differentiation pathways, mitotically stable and sexually transmitted with non-Mendelian patterns. This class of epigenetic changes appeared for some time restricted to the plant world, but examples progressively accumulated of epigenetic inheritance in organisms ranging from mice to humans. Occurrence of paramutation in the mouse and possible mechanisms were then established in the paradigmatic case of a mutant phenotype maintained and hereditarily transmitted by wild type homozygotes. Together with recent findings in plants indicative of a necessary step of RNA amplification in the reference maize paramutation, the mouse studies point to a new role of RNA, as an inducer and hereditary determinant of epigenetic variation. Given the known presence of a wide range of RNAs in human spermatozoa, as well as a number of unexplained cases of familial disease predisposition and transgenerational maintenance, speculations can be extended to possible roles of RNA-mediated inheritance in human biology and pathology.La paramutation est une modification épigénétique héréditaire, découverte chez des plantes et récemment, chez la souris. C'est un changement héréditaire du phénotype associé avec un allèle sauvage à la suite de son passage dans une structure hétérozygote avec un allèle mutant (phénomène quelquefois appelé "conversation interchromosomique"). Souvent il est considéré comme une exception à la base de lois de Mendel, "les allèles sont retrouvés inchangés lors des ségrégations au cours des croisements". Au contraire la paramutation observée chez la souris résulte d'une modification de l'allèle sauvage du gène Kit après transmission à partir d'un hétérozygote avec un allèle mutant "insertion". Le phénotype des taches blanches visibles aisément par la couleur du pelage est transmis en absence de l'allèle inducteur sur plusieurs générations. Il est corrélé avec une diminution du niveau d'ARNm de Kit et une accumulation d'ARN de taille variable de Kit dans les spermatozo?des des souris paramutantes. La micro-injection de l'ARN de l'hétérozygote, ou de l'ARN et des microARN spécifiques de Kit dans l'oeuf fécondé induit le phénotype "taches blanches". Le r?le de l'ARN dans l'établissement et le maintien d'un état épigénétique héréditaire est proposé et discuté.     

Interfering Residues Narrow the Spectrum of MLV Restriction by Human TRIM5α

TRIM5α is a restriction factor that limits infection of human cells by so-called N- but not B- or NB-tropic strains of murine leukemia virus (MLV). Here, we performed a mutation-based functional analysis of TRIM5α-mediated MLV restriction. Our results reveal that changes at tyrosine³³⁶ of human TRIM5α, within the variable region 1 of its C-terminal PRYSPRY domain, can expand its activity to B-MLV and to the NB-tropic Moloney MLV. Conversely, we demonstrate that the escape of MLV from restriction by wild-type or mutant forms of huTRIM5α can be achieved through interdependent changes at positions 82, 109, 110, and 117 of the viral capsid. Together, our results support a model in which TRIM5α-mediated retroviral restriction results from the direct binding of the antiviral PRYSPRY domain to the viral capsid, and can be prevented by interferences exerted by critical residues on either one of these two partners.     

Effects of sub-minimal inhibitory concentrations of EDTA on growth of Escherichia coli and the release of lipopolysaccharide

Abstract Release of lipopolysaccharide from E. coli was studied in the presence of sub-minimal inhibitory concentrations of ethylenediaminetetraacetic acid (EDTA). In untreated cells no release was detected with 50 mM Mg²⁺ in the medium, but a steady release of over 50% of the synthesized lipopolysaccharide was observed with 0.1 mM Mg²⁺. EDTA at MIC/8 led to a 2- to 3-fold higher release, presumably by an adjustment of the concentration of unchelated Mg²⁺ to a value still sustaining normal growth but giving rise to a highly unstable outer membrane. No structural difference was observed between cell-bound and released lipopolysaccharide.