Project description:Expression of bumblebees (Bombus terrestris) from four colonies exposed to 3 different genotypes of the trypanosome parasite Crithidia bombi
Project description:Expression of bumblebees (Bombus terrestris) from four colonies exposed to 3 different genotypes of the trypanosome parasite Crithidia bombi RNA from guts of exposed individuals. Sacrificed 18hr after exposure.
Project description:Methanococcus maripaludis utilizes selenocysteine-(Sec-) containing proteins (selenoproteins), mostly active in the organism’s primary energy metabolism, methanogenesis. Under selenium depletion, M. maripaludis employs a set of enzymes containing cysteine (Cys) instead of Sec. The genes coding for these Sec-/Cys-containing isoforms are the only genes known expression of which is influenced by the selenium status of the cell. Using quantitative proteomics and transcriptomics approx. 7% and 12%, respectively, of all genes/proteins were differentially expressed/synthesized in response to the selenium supply. Some of the genes identified involve methanogenesis, nitrogenase functions, and putative transporters. An increase of transcript abundance for putative transporters under selenium-depleted conditions indicated the organism’s effort to tap into alternative sources of selenium. Selenium sources M. maripaludis is known to utilize are selenite and dimethylselenide. To expand this list, a selenium responsive reporter strain was assessed with nine other, environmentally relevant selenium species. While some had a similar biological window as selenite, others were effectively utilized at lower concentrations. Conversely, selenate and seleno-amino acids were only utilized at unphysiologically high concentrations and two compounds were not utilized at all. To address the role of the selenium-regulated putative transporters in selenium transport, M. maripaludis mutant strains lacking one or two of the putative transporters were tested for the capability to utilize the different selenium species. Of the five putative transporters analyzed by loss-of-function mutagenesis, none appeared to be absolutely required for utilizing any of the selenium species tested, indicating they have redundant and/or overlapping specificities, or are not dedicated selenium transporters.
Project description:Moderate selenium deficiency may lead to an impaired capacity to cope with health challenges. Functional effects of suboptimal selenium intake are not fully known, and biomarkers for an insufficient selenium supply are inadequate. We therefore fed mice diets of moderately deficient or adequate selenium intake for 6 weeks. Changes in global gene expression were monitored by microarray analysis in splenic leukocytes. Genes for four selenoproteins, Sepw1, Gpx1, Selh and Sep15, were the most significantly down-regulated in moderate selenium deficiency, and this was confirmed by quantitative polymerase chain reaction (qPCR). Classification of significantly affected genes revealed that processes related to inflammation, heme biosynthesis, DNA replication and transcription, cell cycle and transport were affected by selenium restriction. Down-regulation by moderate selenium deficiency of specific genes involved in inflammation and heme biosynthesis was confirmed by qPCR. Myeloperoxidase and lysozyme activities were decreased in selenium-restricted leukocytes, providing evidence for functional consequences. Genes for 31 nuclear factor (NF)-κB targets were down-regulated in moderate selenium deficiency, indicating an impaired NF-κB signaling. Together, the observed changes point to a disturbance in inflammatory response. The selenoproteins found here to be sensitive to selenium intake in murine leukocytes might also be useful as biomarkers for a moderate selenium deficiency in humans.
Project description:We studied the application of transcriptome technology in alfalfa selenium treatment. After spraying sodium selenite on the leaves, the process of selenium absorption and assimilation of alfalfa is unknown. The time point of transcriptome determination was determined by measuring the change of selenium content. Our results showed that 12 h was the key point of the change of selenium content in alfalfa, that is, the selenium content increased continuously before 12 h, decreased gradually after 12 h, and remained stable after 48 h. Transcriptome sequencing showed that phosphorus transporter and endocytosis related genes may be involved in selenium absorption at 12 h compared with 0 H. 12-48 h, some thiometabolic pathways may be involved in selenium metabolism and ubiquitination pathway, which may be the detoxification pathway of selenoprotein.
Project description:Transcriptional profiling of mice fed a diet deficient in selenium and folate during weaning and in utero (LL), a diet deficient in selenium and folate during weaning but not in utero (HL), a diet sufficient in selenium and folate during weaning but deficient in utero (LH), and a diet sufficient in selenium and folate during weaning and in utero (HH)
Project description:Selenium is an essential micronutrient. Its recommended daily allowance is not attained by a significant proportion of the population in many countries and its intake has been suggested to affect colorectal carcinogenesis. Therefore, microarrays were used to determine how both selenoprotein and global gene expression patterns in the mouse colon were affected by marginal selenium deficiency comparable to variations in human dietary intakes. Two groups of 12 mice each were fed a selenium-deficient (0.086mg Se/kg) or a selenium-adequate (0.15mg Se/kg) diet. After 6wk, plasma selenium level, liver, and colon glutathione peroxidase (GPx) activity in the deficient group was 12, 34, and 50%, respectively, of that of the adequate group. Differential gene expression was analysed with mouse 44K whole genome microarrays. Pathway analysis by GenMAPP identified the protein biosynthesis pathway as most significantly affected, followed by inflammation, Delta-Notch and Wnt pathways. Selected gene expression changes were confirmed by quantitative real-time PCR. GPx1 and the selenoproteins W, H, and M, responded significantly to selenium intake making them candidates as biomarkers for selenium status. Thus, feeding a marginal selenium-deficient diet resulted in distinct changes in global gene expression in the mouse colon. Modulation of cancer-related pathways may contribute to the higher susceptibility to colon carcinogenesis in low selenium status.
Project description:Oxidation of cysteines by reactive oxygen species (ROS) initiates thermogenesis in brown and beige adipose tissues. Cellular selenols, where sulfur is replaced with selenium, exhibit enhanced reactivity with ROS. Here we developed a mass spectrometric method to interrogate incorporation of selenols into proteins. Unexpectedly, this approach revealed facultative incorporation of selenium into proteins that lack canonical encoding for selenium-containing amino acids. Selenium was selectively incorporated into regulatory sites on key metabolic proteins, including as selenocysteine replacing cysteine at position 253 in UCP1. Remarkably, dietary selenium supplementation elevated facultative incorporation into UCP1, elevated energy expenditure through thermogenic adipose tissue, and protected against obesity. Together, these findings reveal the existence of facultative protein selenation, which correlates with impacts on thermogenic adipocyte function.
Project description:Selenoprotein P is a hepatokine which is essential for maintaining systemic selenium homeostasis and is used as serum biomarker for the selenium status in humans. In addition to selenium, also copper homeostasis is mainly regulated by the liver coordinating systemic distribution of copper bound to ceruloplasmin or excreting surplus copper into the bile. Circulating selenium and copper concentrations are most often negatively correlating, e.g. during aging copper levels are increasing while selenium levels are decreasing. Based on these results, we addressed the question of how both trace elements interfere with each other using the liver-derived cell line HepG2. We observed that copper treatment resulted in a substantial increase of intracellular selenium concentrations. In parallel, extracellular SELENOP concentrations were drastically reduced while SELENOP accumulated within the cells. The same observation was made when using primary murine hepatocytes. Indeed, SELENOP was one of the proteins most strongly downregulated by copper in an untargeted secretome approach. Accumulation of hepatic copper is a characteristic of Wilson’s disease. Accordingly, SELENOP levels were decreasing in the serum of LPP rats, a model of Wilson’s disease starting at disease onset. Also, Wilson’s disease patients showed reduced serum SELENOP concentrations when circulating copper concentrations were low. This positive correlation between copper and ceruloplasmin and SELENOP was also observed in a GWAS analysis of EPIC-Potsdam samples identifying SNP rs11708215 as a modulating factor. Our data indicate that under conditions of a suboptimal selenium supply combined with a high copper intake a functional selenium deficit can become even worse because peripheral tissues such as the brain depend on SELENOP for their selenium supply.
Project description:Background & aim: Micronutrient deficiencies, particularly those of zinc and selenium, are common in persons living with human immunodeficiency virus (PLWHIV), and have been associated with the development of non-AIDS related comorbidities, impaired immune system function, HIV disease progression and mortality. The implementation of intervention strategies on clinically stable long-term-treated PLWHIV could bring potential benefits on impeding or delaying the onset of non-AIDS associated comorbidities, improving their health status and overall quality of life. The aim of the present study is to analyze the effect of zinc and selenium supplementation on body composition, bone mineral density (BMD), lipids profile, glucose and immune system activation and function on PLWHIV on antiretroviral therapy (ART) without metabolic diseases. Methods: This pilot trial was composed of 60 PLWHIV on ART who were randomly assigned to either zinc, selenium, zinc + selenium supplementation or to a control group. Daily supplementation was prescribed during 6 months as follows: the zinc group received 30 mg of zinc gluconate, the selenium group received 200 mcg of selenium yeast and the zinc + selenium group received both micronutrients at the same doses and presentations. Individuals in the control group were followed during the same time without any nutritional supplementation. Body composition (weight, body mass index [BMI], fat mass and muscle mass), BMD, blood pressure, blood biochemical parameters (cholesterol, glucose and triglycerides), serum zinc and selenium concentrations, CD4+ T cell count and CD4+ and CD8+ T cells immune activation were assessed before and after supplementation. One individual of each supplementation group and one of the control group were analyzed for single cell transcriptomics before and after supplementation. Results: BMI (p=0.03), fat mass in kg (p=0.03) and percentage (p=0.02), as well as trunk fat (p=0.01), were significantly decreased after selenium supplementation. No changes were observed for body composition, BMD, biochemical determinations or blood pressure on the other intervention groups after supplementation (p>0.05 in all cases). The CD4+ T cells frequency and count significantly increased after selenium and zinc supplementation (p=0.03, p=0.05 respectively). CD4+ and CD8+ T-cell immune activation did not change after supplementation (p>0.05 in both cases). On the single cell transcriptome analysis, zinc and selenium supplementation significantly change de expression of genes associated with the function of naive and memory CD8+ T cells (adjusted p<0.05 in all cases). Conclusions: Selenium supplementation have beneficial effects on the body composition, while zinc and selenium supplementation increased CD4+ T cell replenishment of PLWHIV on long-term ART without metabolic diseases. Additionally, zinc and selenium supplementation modified the expression of genes associated with the function of naive and memory CD8+ T cells. Zinc and selenium supplementation are a simple, low-cost, and safe nutritional treatment that represents a complementary intervention to improve the health status and increase the quality of life of clinically stable PLWHIV without metabolic diseases. Registered: Under ClinicalTrails.gov identifier NCT03421314