Oestrogènes et reproduction masculine

The role of estrogen on male reproductive function has become clearer in the last decade. During these years the study of the effect of testosterone, estrogen or an aromatase inhibitor in hypogonadal men provided a first evidence of the effects of estrogens in the regulation of gonadotropin secretion. At the same time, the development of a line of transgenic male mice lacking estrogen receptor α, estrogen receptor β or aromatase gene provided further evidence about the role of estrogens not only in the regulation of gonadotropin secretion, but also on the effects of estrogens on testicular function and development. A confirmation of these actions of estrogens came from the observation of naturally occurring mutations of the estrogen receptor and of the aromatase gene in human males. Based on these data it has been demonstrated that estrogens are major regulators of gonadotropin secretion acting both at pituitary and hypotalamic level. The presence in the human reproductive structures of estrogen receptor α, estrogen receptor β and the aromatase enzyme indicates the existence of receptor α, estrogen receptor β or aromatase estrogen actions at this level. Anyway, the precise role of estrogens in testicular development and function and on the regulation of human spermatogenesis has not yet been precisely clarified.     

Assessing the Fecal Microbiota: An Optimized Ion Torrent 16S rRNA Gene-Based Analysis Protocol

Assessing the distribution of 16S rRNA gene sequences within a biological sample represents the current state-of-the-art for determination of human gut microbiota composition. Advances in dissecting the microbial biodiversity of this ecosystem have very much been dependent on the development of novel high-throughput DNA sequencing technologies, like the Ion Torrent. However, the precise representation of this bacterial community may be affected by the protocols used for DNA extraction as well as by the PCR primers employed in the amplification reaction. Here, we describe an optimized protocol for 16S rRNA gene-based profiling of the fecal microbiota.     

Identification of an epithelial protein related to the desmosome and intermediate filament network

Using a mAb, referred to as 08L, we have identified a protein, of M(r) approximately 140,000, associated with desmosomes of epithelial cells. The 08L antibody stained the intracellular side of lateral cell margins of monolayer epithelial cells but did not stain cell margins free of cell contact. Immunoelectron microscopy revealed that the 08L antigen was localized to the cytosolic surface of the desmosomal plaque near points of intermediate filament convergence with apparently little staining of the desmosomal plaque proper. Western blots revealed the 08L antigen to be a protein, of M(r) approximately 140,000, found in the Triton-X 100 insoluble pellet. High salt-containing buffers extracted the 08L antigen from the insoluble material. Examination of the assembly of 08L to the desmosome complex, in cells grown in low confluent culture or in calcium-switch assays, by double immunofluorescence with 08L and anti-desmoplakin antibody, revealed that 08L was recruited to morphologically identifiable desmosomes. 08L antigen may exist in a cytosolic pool prior to assembly to the cell surface. The solubility of 08L in low calcium and normal calcium conditions, however, was similar. 08L association to the desmosome was correlated with increased organization of the intermediate filament network. We suggest that the 08L antigen may be involved in the organization and stabilization of the desmosome-IF complexes of epithelia.     

CRISPR/Cas9-mediated gfp gene inactivation in Arabidopsis suspension cells

Molecular Biology Reports - Targeted genome editing using CRISPR/Cas9 is a promising technology successfully verified in various plant species; however, it has hardly been used in plant cell...     

Intensification of agriculture in southwestern Germany between the Bronze Age and Medieval period,based on archaeobotanical data from Baden-Württemberg

Vegetation History and Archaeobotany - A system of farming with an alternation of land use between being cultivated or left fallow as grassland (Feldgraswirtschaft) developed in southwestern...     

Discovery of 17 conserved structural RNAs in fungi

Many non-coding RNAs with known functions are structurally conserved: their intramolecular secondary and tertiary interactions are maintained across evolutionary time. Consequently, the presence of conserved structure in multiple sequence alignments can be used to identify candidate functional non-coding RNAs. Here, we present a bioinformatics method that couples iterative homology search with covariation analysis to assess whether a genomic region has evidence of conserved RNA structure. We used this method to examine all unannotated regions of five well-studied fungal genomes (Saccharomyces cerevisiae, Candida albicans, Neurospora crassa, Aspergillus fumigatus, and Schizosaccharomyces pombe). We identified 17 novel structurally conserved non-coding RNA candidates, which include four H/ACA box small nucleolar RNAs, four intergenic RNAs and nine RNA structures located within the introns and untranslated regions (UTRs) of mRNAs. For the two structures in the 3′ UTRs of the metabolic genes GLY1 and MET13, we performed experiments that provide evidence against them being eukaryotic riboswitches.     

Functional LCAT deficiency in human apolipoprotein A-I transgenic, SR-BI knockout mice

Reduction of plasma LCAT activity has been observed in several conditions in which the size of HDL particles is increased; however, the mechanism of this reduction remains elusive. We investigated the plasma activity, mass, and in vivo catabolism of LCAT and its association with HDL particles in human apolipoprotein A-I transgenic, scavenger receptor class B type I knockout (hA-ITg SR-BI-/-) mice. Compared with hA-ITg mice, hA-ITg SR-BI-/- mice had a 4-fold higher total plasma cholesterol concentration, which occurred predominantly in 13-18 nm diameter HDL particles, a significant reduction in plasma esterified cholesterol-total cholesterol (EC/TC) ratio, and significantly lower plasma LCAT activity, suggesting a decrease in LCAT protein. However, LCAT protein in plasma, hepatic mRNA for LCAT, and in vivo turnover of 35S-radiolabeled LCAT were similar in both genotypes of mice. HDL from hA-ITg SR-BI-/- mice was enriched in sphingomyelin (SM), relative to phosphatidylcholine, and had less associated [35S]LCAT radiolabel and endogenous LCAT activity compared with HDL from hA-ITg mice. We conclude that the decreased EC/TC ratio in the plasma of hA-ITg SR-BI-/- mice is attributed to a reduction in LCAT reactivity with SM-enriched HDL particles.     

Expression of PSACH-associated mutant COMP in tendon fibroblasts leads to increased apoptotic cell death irrespective of the secretory characteristics of mutant COMP.

OBJECTIVE: Pseudoachondroplasia (PSACH) is a dominantly inherited chondrodysplasia associated with mutations of cartilage oligomeric matrix protein (COMP), characterized clinically by disproportionate dwarfism and laxity of joints and ligaments. Studies in chondrocytes and cartilage biopsies suggest that the cartilage disease is caused by retention of mutant COMP in the endoplasmic reticulum of chondrocytes and by disruption of the collagen network of the extracellular matrix. The pathogenesis of the tendon disease remains unclear in the absence of a cell culture model, with available tendon biopsies leading to conflicting results with respect to the intracellular retention of mutant COMP. METHODS: We established a cell culture model using adenoviral gene transfer in tendon fibroblast cultures. We compared the effect of expression of three PSACH-associated COMP mutants and the wildtype protein on COMP secretion, matrix composition and cellular viability. RESULTS: Our results show that mutants D475N and D469Delta are retained within the endoplasmic reticulum of tendon cells similar to what is known from chondrocytes, whereas mutant H587R is secreted like wildtype COMP. In spite of this difference, the collagen I matrix formed in culture appears disturbed for all three mutants. All COMP-mutants induce apoptotic cell death irrespective of their differing secretion patterns. CONCLUSION: Pathogenic pathways leading to tendon disease in humans appear to be heterogeneous between different COMP mutants.