46 research outputs found
Characterization of oxylipins and dioxygenase genes in the asexual fungus Aspergillus niger
<p>Abstract</p> <p>Background</p> <p><it>Aspergillus niger </it>is an ascomycetous fungus that is known to reproduce through asexual spores, only. Interestingly, recent genome analysis of <it>A. niger </it>has revealed the presence of a full complement of functional genes related to sexual reproduction <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>. An example of such genes are the dioxygenase genes which in <it>Aspergillus nidulans</it>, have been shown to be connected to oxylipin production and regulation of both sexual and asexual sporulation <abbrgrp><abbr bid="B2">2</abbr><abbr bid="B3">3</abbr><abbr bid="B4">4</abbr></abbrgrp>. Nevertheless, the presence of sex related genes alone does not confirm sexual sporulation in <it>A. niger</it>.</p> <p>Results</p> <p>The current study shows experimentally that <it>A. niger </it>produces the oxylipins 8,11-dihydroxy octadecadienoic acid (8,11-diHOD), 5,8-dihydroxy octadecadienoic acid (5,8-diHOD), lactonized 5,8-diHOD, 8-hydroxy octadecadienoic acid (8-HOD), 10-hydroxy octadecadienoic acid (10-HOD), small amounts of 8-hydroxy octadecamonoenoic acid (8-HOM), 9-hydroxy octadecadienoic acid (9-HOD) and 13-hydroxy octadecadienoic acid (13-HOD). Importantly, this study shows that the <it>A. niger </it>genome contains three putative dioxygenase genes, <it>ppoA</it>, <it>ppoC </it>and <it>ppoD</it>. Expression analysis confirmed that all three genes are indeed expressed under the conditions tested.</p> <p>Conclusion</p> <p><it>A. niger </it>produces the same oxylipins and has similar dioxygenase genes as <it>A. nidulans</it>. Their presence could point towards the existence of sexual reproduction in <it>A. niger </it>or a broader role for the gene products in physiology, than just sexual development.</p
Intracellular Localization of Lipoxygenases-1 and -2 in Germinating Soybean Seeds by Indirect Labeling with Protein A-Colloidal Gold Complexes
Analysis of shared common genetic risk between amyotrophic lateral sclerosis and epilepsy
Because hyper-excitability has been shown to be a shared pathophysiological mechanism, we used the latest and largest genome-wide studies in amyotrophic lateral sclerosis (n = 36,052) and epilepsy (n = 38,349) to determine genetic overlap between these conditions. First, we showed no significant genetic correlation, also when binned on minor allele frequency. Second, we confirmed the absence of polygenic overlap using genomic risk score analysis. Finally, we did not identify pleiotropic variants in meta-analyses of the 2 diseases. Our findings indicate that amyotrophic lateral sclerosis and epilepsy do not share common genetic risk, showing that hyper-excitability in both disorders has distinct origins
Skewed X-inactivation is common in the general female population
X-inactivation is a well-established dosage compensation mechanism ensuring that X-chromosomal genes are expressed at comparable levels in males and females. Skewed X-inactivation is often explained by negative selection of one of the alleles. We demonstrate that imbalanced expression of the paternal and maternal X-chromosomes is common in the general population and that the random nature of the X-inactivation mechanism can be sufficient to explain the imbalance. To this end, we analyzed blood-derived RNA and whole-genome sequencing data from 79 female children and their parents from the Genome of the Netherlands project. We calculated the median ratio of the paternal over total counts at all X-chromosomal heterozygous single-nucleotide variants with coverage ≥10. We identified two individuals where the same X-chromosome was inactivated in all cells. Imbalanced expression of the two X-chromosomes (ratios ≤0.35 or ≥0.65) was observed in nearly 50% of the population. The empirically observed skewing is explained by a theoretical model where X-inactivation takes place in an embryonic stage in which eight cells give rise to the hematopoietic compartment. Genes escaping X-inactivation are expressed from both alleles and therefore demonstrate less skewing than inactivated genes. Using this characteristic, we identified three novel escapee genes (SSR4, REPS2, and SEPT6), but did not find support for many previously reported escapee genes in blood. Our collective data suggest that skewed X-inactivation is common in the general population. This may contribute to manifestation of symptoms in carriers of recessive X-linked disorders. We recommend that X-inactivation results should not be used lightly in the interpretation of X-linked variants