A quantitative morphological study of human Leydig cells from birth to adulthood

Summary Human testicular specimens were obtained from biopsies and autopsies covering the period from birth to adulthood. The number of testosterone-containing Leydig cells was determined using the peroxidase-anti-peroxidase method. This number decreased markedly from 3–6 months of age to the end of the first year of life and, up to 6 years of age, only a small number of testosterone-containing cells was found. From 6 years onwards the number of Leydig cells progressively increased. Ultrastructural examination revealed four types of Leydig cells: (1) fetal-type Leydig cells (from birth to 1 year of age) with round nuclei, abundant smooth endoplasmic reticulum and mitochondria with tubular cristae; (2) infantile-type Leydig cells (from birth to 8–10 years of age), showing a multilobated nucleus, moderately abundant smooth endoplasmic reticulum, some lipid droplets and mitochondria with parallel cristae; (3) prepubertal, partially differentiated Leydig cells (from 6 years of age onwards) with regularly-outlined round nuclei, abundant smooth endoplasmic reticulum, mitochondria with tubular cristae, and some lipid droplets and lipofuscin granules; and (4) mature adult Leydig cells (from 8–10 years of age onwards). The ultrastructure of the infantile-type Leydig cells and the lack of delay between the disappearance of the fetal-type Leydig cells and the appearance of infantile-type Leydig cells suggest that fetal-type Leydig cells give rise to the infantile-type Leydig cells. Before puberty, myofibroblast-like precursor cells differentiate into the prepubertal, partially differentiated Leydig cells, which complete their differentiation into the adult Leydig cells.This work was supported by grants from the Comisión Asesora de Investigation Científica y Técnica, and the Fondo de Investigaciones Sanitarias de la Seguridad Social, Madrid, Spain     

Monthly day/night changes and seasonal daily rhythms of sexual steroids in Senegal sole (Solea senegalensis) under natural fluctuating or controlled environmental conditions

In this paper we attempted to investigate the existence of daily fluctuations on plasma sexual steroids (17beta-estradiol, E(2) and testosterone, T) in Senegal sole (Solea senegalensis) females. We described the monthly day/night concentrations and seasonal daily rhythms in animals reared under natural photo- and thermo-period. In addition, the influence of the natural annual fluctuation of the water temperature on the plasma concentration of these steroids was investigated, using one group of Senegal sole under a natural photoperiod, but with an attenuated thermal cycle (around 17-20 degrees C) for one year. Although no significant day/night differences were detected in monthly samplings, the existence of an annual rhythm of E(2) and T (p<0.01) with an acrophase in February was revealed by COSINOR analysis. Maximum values were reached in March for both steroids (6.1+/-1.7 ng mL(-1) at mid-dark, MD and 4.0+/-0.6 ng mL(-1) at mid-light, ML for E2 and 1.4+/-0.4 ng mL(-1) at MD and 0.8+/-0.1 ng mL(-1) at ML for T) in anticipation of the spawning season (May-June). As regards seasonal daily rhythms, the presence of daily oscillations was revealed. At the spring solstice (21st March) a daily rhythm was observed for both steroids (COSINOR, p<0.01), with an acrophase at 20:00 h (E(2)) and at 21:08 h (T). In summer, autumn and winter no daily rhythms were observed due to the low steroid levels at those seasons. When Senegal sole females were submitted to an attenuated annual thermal cycle, the steroid rhythm disappeared (there was no surge in spring, as in the control group) and these fish did not spawn, despite being subjected to natural photoperiod conditions. This result underlined the importance of the natural annual fluctuation of water temperature and photoperiod on the synchronization of the spawning season and on the onset of steroidogenesis.     

Glutamine synthetase sequence evolution in the mycobacteria and their use as molecular markers for Actinobacteria speciation

Background  

Although the gene encoding for glutamine synthetase (gln A) is essential in several organisms, multiple glnA copies have been identified in bacterial genomes such as those of the phylum Actinobacteria, notably the mycobacterial species. Intriguingly, previous reports have shown that only one copy (gln A1) is essential for growth in M. tuberculosis, while the other copies (gln A2, gln A3 and gln A4) are not.     

Changes in genomic methylation patterns during the formation of triploid asexual dandelion lineages

DNA methylation is an epigenetic mechanism that has the potential to affect plant phenotypes and that is responsive to environmental and genomic stresses such as hybridization and polyploidization. We explored de novo methylation variation that arises during the formation of triploid asexual dandelions from diploid sexual mother plants using methylation‐sensitive amplified fragment length polymorphism (MS‐AFLP) analysis. In dandelions, triploid apomictic asexuals are produced from diploid sexual mothers that are fertilized by polyploid pollen donors. We asked whether the ploidy level change that accompanies the formation of new asexual lineages triggers methylation changes that contribute to heritable epigenetic variation within novel asexual lineages. Comparison of MS‐AFLP and AFLP fragment inheritance in a diploid × triploid cross revealed de novo methylation variation between triploid F₁ individuals. Genetically identical offspring of asexual F₁ plants showed modest levels of methylation variation, comparable to background levels as observed among sibs in a long‐established asexual lineage. Thus, the cross between ploidy levels triggered de novo methylation variation between asexual lineages, whereas it did not seem to contribute directly to variation within new asexual lineages. The observed background level of methylation variation suggests that considerable autonomous methylation variation could build up within asexual lineages under natural conditions.     

Reset of a critically disturbed microbial ecosystem: faecal transplant in recurrent Clostridium difficile infection

Recurrent Clostridium difficile infection (CDI) can be effectively treated by infusion of a healthy donor faeces suspension. However, it is unclear what factors determine treatment efficacy. By using a phylogenetic microarray platform, we assessed composition, diversity and dynamics of faecal microbiota before, after and during follow-up of the transplantation from a healthy donor to different patients, to elucidate the mechanism of action of faecal infusion. Global composition and network analysis of the microbiota was performed in faecal samples from nine patients with recurrent CDI. Analyses were performed before and after duodenal donor faeces infusion, and during a follow-up of 10 weeks. The microbiota data were compared with that of the healthy donors. All patients successfully recovered. Their intestinal microbiota changed from a low-diversity diseased state, dominated by Proteobacteria and Bacilli, to a more diverse ecosystem resembling that of healthy donors, dominated by Bacteroidetes and Clostridium groups, including butyrate-producing bacteria. We identified specific multi-species networks and signature microbial groups that were either depleted or restored as a result of the treatment. The changes persisted over time. Comprehensive and deep analyses of the microbiota of patients before and after treatment exposed a therapeutic reset from a diseased state towards a healthy profile. The identification of microbial groups that constitute a niche for C. difficile overgrowth, as well as those driving the reinstallation of a healthy intestinal microbiota, could contribute to the development of biomarkers predicting recurrence and treatment outcome, identifying an optimal microbiota composition that could lead to targeted treatment strategies.     

PTRF/cavin-1 and MIF proteins are identified as non-small cell lung cancer biomarkers by label-free proteomics

With the completion of the human genome sequence, biomedical sciences have entered in the "omics" era, mainly due to high-throughput genomics techniques and the recent application of mass spectrometry to proteomics analyses. However, there is still a time lag between these technological advances and their application in the clinical setting. Our work is designed to build bridges between high-performance proteomics and clinical routine. Protein extracts were obtained from fresh frozen normal lung and non-small cell lung cancer samples. We applied a phosphopeptide enrichment followed by LC-MS/MS. Subsequent label-free quantification and bioinformatics analyses were performed. We assessed protein patterns on these samples, showing dozens of differential markers between normal and tumor tissue. Gene ontology and interactome analyses identified signaling pathways altered on tumor tissue. We have identified two proteins, PTRF/cavin-1 and MIF, which are differentially expressed between normal lung and non-small cell lung cancer. These potential biomarkers were validated using western blot and immunohistochemistry. The application of discovery-based proteomics analyses in clinical samples allowed us to identify new potential biomarkers and therapeutic targets in non-small cell lung cancer.     

Androgens contribute to sex differences in myocardial remodeling under pressure overload by a mechanism involving TGF-β

Background

In clinical studies, myocardial remodeling in aortic valve stenosis appears to be more favorable in women than in men, even after menopause. In the present study, we assessed whether circulating androgens contribute to a less favorable myocardial remodeling under pressure overload in males. We examined sex-related differences in one-year-old male and female mice. Whereas male mice at this age exhibited circulating androgen levels within the normal range for young adults, the circulating estrogens in females were reduced. The contribution of gonadal androgens to cardiac remodeling was analyzed in a group of same-age castrated mice.

Methodology/Principal Findings

Animals were subjected to transverse aortic constriction (TAC). Echocardiography was performed 2 weeks after TAC and myocardial mRNA levels of TGF-βs, Smads 2 and 3, collagens, fibronectin, β-myosin heavy chain and α-myosin heavy chain were determined by q-PCR. Protein detection of p-SMAD2/3 was performed by Western Blot. Histological staining of fibrosis was performed with picrosirius red and Masson''s trichrome. Compared with females, males developed more severe tissue fibrosis, LV dilation and hemodynamic dysfunction. TAC-males showed higher myocardial expression levels of TGF-βs and the treatment with a neutralizing antibody to TGF-β prevented myocardial fibrosis development. Orchiectomy diminished TAC-induced up-regulation of TGF-βs and TGF-β target genes, and it also reduced fibrosis and hemodynamic dysfunction. The capability of androgens to induce TGF-β expression was confirmed in NIH-3T3 fibroblasts and H9C2 cardiomyocytes exposed to dihydrotestosterone.

Conclusions/Significance

Our results indicate that circulating androgens are responsible for the detrimental effects in the myocardium of older male mice subjected to pressure overload through a mechanism involving TGF-βs.     

Phylogeny of some Fusarium species, as determined by large-subunit rRNA sequence comparison

Fifty-two strains from eight species of Fusarium were analyzed by rapid rRNA sequencing. Two highly variable stretches (138 and 214 nucleotides) of the 5' end of the 28S-like rRNA molecule were sequenced. Such stretches permit evaluation of the divergence between closely related species and even between varieties within a species. The phylogenetic tree computed from the number of nucleotide differences shows seven Fusarium species to be more closely related to one another than the eighth species, F. nivale, is to them. On the basis of these data, we discuss both the phylogenetic value of taxonomical criteria and the impact of our findings on the demarcation of the genus Fusarium. We conclude that this method is suitable for establishing a precise phylogeny between closely related species within a genus.