50 research outputs found

    A sensetive zonagenetic assay for rapid in vivo assessment of estrogenic potency of xenobiotics and mycotoxins

    Get PDF
    Mounting evidence confirms that hepatic biosynthetic processes are essential for female sexual maturation in fish, which is directly controlled by estrogens. These oogenetic events (zonagenesis and vitellogenesis) are induced in both sexes by estrogens. In this paper, we report the induction of zona radiata (zr) proteins and vitellogenin in primary hepatocytes from Atlantic salmon (Salmo salar L.) exposed to xenoestrogens and mycotoxins. Cells were treated with doses of 1, 5, and 10 microM 4-nonylphenol (4-NP), o, p'-DDT, lindane ([gamma]-HCH), and bisphenol A (BPA), which all induced zr proteins and vitellogenin in an approximate dose-dependent manner. Hepatocytes were also treated with combinations of xenoestrogens at 1 or 2 microM, resulting in elevated levels of both zr proteins and vitellogenin, compared to single treatment. The estrogenic activity of the mycotoxin zearalenone (ZEA) and its metabolites [alpha]-ZEA) and ss-zearalenol (ss-ZEA)], with regard to zonagenesis and vitellogenesis, was assessed in this assay system. Mycotoxins were used at concentrations of 10, 100, or 1,000 nM. All induced zr proteins and vitellogenin, with [alpha]-ZEA being the strongest inducer. When cells were treated with xenoestrogens or mycotoxins in combination with an estrogen receptor inhibitor (ICI 182,780), the induction of both zr proteins and vitellogenin was inhibited in all cases. Thus, the reported estrogen effects are bonafide estrogen responses. Zona radiata proteins were more responsive than vitellogenin to both xenoestrogens and mycotoxins. The versatility and sensitivity of the hepatocyte assay demonstrates that biosynthesis of zr proteins provides a new supplementary method for estimating xenoestrogenicity and mycotoxin action.publishedVersio

    Mendelian randomisation analysis provides no evidence for a relationship between adult height and testicular cancer risk.

    Get PDF
    Observational studies have suggested anthropometric traits, particularly increased height are associated with an elevated risk of testicular cancer (testicular germ cell tumour). However, there is an inconsistency between study findings, suggesting the possibility of the influence of confounding factors. To examine the association between anthropometric traits and testicular germ cell tumour using an unbiased approach, we performed a Mendelian randomisation study. We used genotype data from genome wide association studies of testicular germ cell tumour totalling 5518 cases and 19,055 controls. Externally weighted polygenic risk scores were created and used to evaluate associations with testicular germ cell tumour risk per one standard deviation (s.d) increase in genetically-defined adult height, adult BMI, adult waist hip ratio adjusted for BMI (WHRadjBMI), adult hip circumference adjusted for BMI (HIPadjBMI), adult waist circumference adjusted for BMI (WCadjBMI), birth weight (BW) and childhood obesity. Mendelian randomisation analysis did not demonstrate an association between any anthropometric trait and testicular germ cell tumour risk. In particular, despite good power, there was no global evidence for association between height and testicular germ cell tumour. However, three SNPs for adult height individually showed association with testicular germ cell tumour (rs4624820: OR = 1.47, 95% CI: 1.41-1.55, p = 2.7 × 10-57 ; rs12228415: OR = 1.17, 95% CI: 1.11-1.22, p = 3.1 × 10-10 ; rs7568069: OR = 1.13, 95% CI: 1.07-1.18, p = 1.1 × 10-6 ). This Mendelian randomisation analysis, based on the largest testicular germ cell tumour genome wide association dataset to date, does not support a causal etiological association between anthropometric traits and testicular germ cell tumour aetiology. Our findings are more compatible with confounding by shared environmental factors, possibly related to prenatal growth with exposure to these risk factors occurring in utero

    Methylobacterium Genome Sequences: A Reference Blueprint to Investigate Microbial Metabolism of C1 Compounds from Natural and Industrial Sources

    Get PDF
    Methylotrophy describes the ability of organisms to grow on reduced organic compounds without carbon-carbon bonds. The genomes of two pink-pigmented facultative methylotrophic bacteria of the Alpha-proteobacterial genus Methylobacterium, the reference species Methylobacterium extorquens strain AM1 and the dichloromethane-degrading strain DM4, were compared. Methodology/Principal Findings The 6.88 Mb genome of strain AM1 comprises a 5.51 Mb chromosome, a 1.26 Mb megaplasmid and three plasmids, while the 6.12 Mb genome of strain DM4 features a 5.94 Mb chromosome and two plasmids. The chromosomes are highly syntenic and share a large majority of genes, while plasmids are mostly strain-specific, with the exception of a 130 kb region of the strain AM1 megaplasmid which is syntenic to a chromosomal region of strain DM4. Both genomes contain large sets of insertion elements, many of them strain-specific, suggesting an important potential for genomic plasticity. Most of the genomic determinants associated with methylotrophy are nearly identical, with two exceptions that illustrate the metabolic and genomic versatility of Methylobacterium. A 126 kb dichloromethane utilization (dcm) gene cluster is essential for the ability of strain DM4 to use DCM as the sole carbon and energy source for growth and is unique to strain DM4. The methylamine utilization (mau) gene cluster is only found in strain AM1, indicating that strain DM4 employs an alternative system for growth with methylamine. The dcm and mau clusters represent two of the chromosomal genomic islands (AM1: 28; DM4: 17) that were defined. The mau cluster is flanked by mobile elements, but the dcm cluster disrupts a gene annotated as chelatase and for which we propose the name “island integration determinant” (iid).Conclusion/Significance These two genome sequences provide a platform for intra- and interspecies genomic comparisons in the genus Methylobacterium, and for investigations of the adaptive mechanisms which allow bacterial lineages to acquire methylotrophic lifestyles.Organismic and Evolutionary Biolog

    Identification of 22 susceptibility loci associated with testicular germ cell tumors

    Get PDF
    Testicular germ cell tumors (TGCT) are the most common tumor in young white men and have a high heritability. In this study, the international Testicular Cancer Consortium assemble 10,156 and 179,683 men with and without TGCT, respectively, for a genome-wide association study. This meta-analysis identifies 22 TGCT susceptibility loci, bringing the total to 78, which account for 44% of disease heritability. Men with a polygenic risk score (PRS) in the 95th percentile have a 6.8-fold increased risk of TGCT compared to men with median scores. Among men with independent TGCT risk factors such as cryptorchidism, the PRS may guide screening decisions with the goal of reducing treatment-related complications causing long-term morbidity in survivors. These findings emphasize the interconnected nature of two known pathways that promote TGCT susceptibility: male germ cell development within its somatic niche and regulation of chromosomal division and structure, and implicate an additional biological pathway, mRNA translation

    Standards in semen examination: publishing reproducible and reliable data based on high-quality methodology

    Get PDF
    Biomedical science is rapidly developing in terms of more transparency, openness and reproducibility of scientific publications. This is even more important for all studies that are based on results from basic semen examination. Recently two concordant documents have been published: the 6th edition of the WHO Laboratory Manual for the Examination and Processing of Human Semen, and the International Standard ISO 23162:2021. With these tools, we propose that authors should be instructed to follow these laboratory methods in order to publish studies in peer-reviewed journals, preferable by using a checklist as suggested in an Appendix to this article

    A sensetive zonagenetic assay for rapid in vivo assessment of estrogenic potency of xenobiotics and mycotoxins

    No full text
    Mounting evidence confirms that hepatic biosynthetic processes are essential for female sexual maturation in fish, which is directly controlled by estrogens. These oogenetic events (zonagenesis and vitellogenesis) are induced in both sexes by estrogens. In this paper, we report the induction of zona radiata (zr) proteins and vitellogenin in primary hepatocytes from Atlantic salmon (Salmo salar L.) exposed to xenoestrogens and mycotoxins. Cells were treated with doses of 1, 5, and 10 microM 4-nonylphenol (4-NP), o, p'-DDT, lindane ([gamma]-HCH), and bisphenol A (BPA), which all induced zr proteins and vitellogenin in an approximate dose-dependent manner. Hepatocytes were also treated with combinations of xenoestrogens at 1 or 2 microM, resulting in elevated levels of both zr proteins and vitellogenin, compared to single treatment. The estrogenic activity of the mycotoxin zearalenone (ZEA) and its metabolites [alpha]-ZEA) and ss-zearalenol (ss-ZEA)], with regard to zonagenesis and vitellogenesis, was assessed in this assay system. Mycotoxins were used at concentrations of 10, 100, or 1,000 nM. All induced zr proteins and vitellogenin, with [alpha]-ZEA being the strongest inducer. When cells were treated with xenoestrogens or mycotoxins in combination with an estrogen receptor inhibitor (ICI 182,780), the induction of both zr proteins and vitellogenin was inhibited in all cases. Thus, the reported estrogen effects are bonafide estrogen responses. Zona radiata proteins were more responsive than vitellogenin to both xenoestrogens and mycotoxins. The versatility and sensitivity of the hepatocyte assay demonstrates that biosynthesis of zr proteins provides a new supplementary method for estimating xenoestrogenicity and mycotoxin action

    Akt/PTEN signaling mediates estrogen-dependent proliferation of primordial germ cells in vitro

    No full text
    Testicular tumors in humans are reported to be significantly increasing in incidence. Embryo exposure to environmental estrogens has been proposed as one of the possible underlying causes. In mice, genetic, immunological, and experimental evidence suggest that germ cell testicular tumors may derive from primordial germ cells (PGCs), the embryonic precursors of gametes. Here we show that relatively high concentrations of estrogens stimulate mouse PGC growth in vitro through the somatic cells of the gonadal ridges. Moreover, we found that estrogens stimulate the transcription of the Steel gene and the production of c-Kit ligand in gonadal somatic cells, and that this growth factor is likely to be responsible for the observed stimulation of PGC growth via an Akt/PTEN pathway. Finally, we show that estrogen stimulation of gonadal somatic cells in culture, in combination with PTEN down-regulation in PGCs and the presence of leukemia inhibitory factor in the culture medium, result in high frequency of PGC transformation in tumorigenic cells. Based on these results, we present a novel experimental in vitro model for tumorigenic germ cell transformation and identify molecular pathways likely involved in development of germ cell tumors after estrogen exposure

    Linkage between cryptorchidism, hypospadias, and GGN repeat length in the androgen receptor gene

    No full text
    Although sufficient androgen receptor (AR) function is crucial for normal male sexual differentiation, single-point mutations in the AR gene are infrequent in the two most common male congenital malformations, hypospadias and cryptorchidism. Because polymorphic CAG and GGN segments regulate AR function, we investigated whether there was any association between these polymorphisms and mentioned malformations. Genotyping was performed by direct sequencing of DNA from patients diagnosed with hypospadias (n = 51) and cryptorchidism ( n = 23) and controls ( n = 210). The subjects with hypospadias were divided into subgroups of glanular, penile, and penoscrotal hypospadias. Median GGN lengths were significantly higher ( 24 vs. 23) among both subjects with cryptorchidism, compared with controls ( P = 0.001), and those with penile hypospadias, compared with either controls ( P = 0.003) or glanular and penoscrotal hypospadias combined ( P = 0.018). The frequency of cases with GGN 24 or more vs. GGN = 23, differed significantly among those with cryptorchidism (65/35%), compared with controls (31/54%) ( P = 0.012), and among subjects with penile hypospadias (69/31%), compared with either controls ( P = 0.035) or glanular or penoscrotal hypospadias combined (32/55%) ( P = 0.056). There were no significant differences in CAG lengths between the cases and controls. Our findings indicate an association between GGN length and the risk of cryptorchidism and penile hypospadias, both conditions considered consequences of low androgenicity
    corecore