\u3cem\u3eC. elegans\u3c/em\u3e Synmuv B Proteins Regulate Spatial and Temporal Chromatin Compaction During Development

Tissue-specific establishment of repressive chromatin through creation of compact chromatin domains during development is necessary to ensure proper gene expression and cell fate. Caenorhabditis elegans synMuv B proteins are important for the soma/germline fate decision and mutants demonstrate ectopic germline gene expression in somatic tissue, especially at high temperature. We show that C. elegans synMuv B proteins regulate developmental chromatin compaction and that the timing of chromatin compaction is temperature sensitive in both wild type and synMuv B mutants. Chromatin compaction in mutants is delayed into developmental time periods when zygotic gene expression is upregulated and demonstrates an anterior-to-posterior pattern. Loss of this patterned compaction coincides with the developmental time period of ectopic germline gene expression, which leads to a developmental arrest in synMuv B mutants. Finally, accelerated cell division rates at elevated temperature may contribute to a lack of coordination between expression of tissue specific transcription programs and chromatin compaction at high temperature. Thus, chromatin organization during development is regulated both spatially and temporally by synMuv B proteins to establish repressive chromatin in a tissue-specific manner to ensure proper gene expression

Temperature Stressed \u3cem\u3eCaenorhabditis elegans\u3c/em\u3e Males Fail to Mate Successfully and Successful Males Produce Very Few Viable Cross Progeny

Exposure to moderate temperature stress can have profoundly negative effects on an organism’s reproductive capacity at temperatures where there are minimal or indiscernible effects on the organism as a whole. These negative effects are often more pronounced in males of the species that produce sperm. Previously we showed that few males of Caenorhabditis elegans wild type strains are able to successfully produce any cross progeny after experiencing temperature stress. However, these experiments did not assess the number of progeny from temperature stressed males. To understand if temperature stress can reduce the number of progeny a male sires, we crossed temperature stressed males of three wild type strains of C. elegans: JU1171, LKC34, and N2, to strain matched hermaphrodites of their own genetic background or to uncoordinated hermaphrodites in the N2 background. We found that significantly fewer males exposed to moderate temperature stress can successfully mate and that the small number of males in the population that do successfully mate produce significantly fewer viable cross progeny than unstressed controls. Our results suggest that exposure to moderate temperature stress significantly reduces male C. elegans chances at reproducing similar to what is seen in other organisms

Copper Oxide Nanoparticles Impact Several Toxicological Endpoints and Cause Neurodegeneration in \u3cem\u3eCaenorhabditis elegans\u3c/em\u3e

Engineered nanoparticles are becoming increasingly incorporated into technology and consumer products. In 2014, over 300 tons of copper oxide nanoparticles were manufactured in the United States. The increased production of nanoparticles raises concerns regarding the potential introduction into the environment or human exposure. Copper oxide nanoparticles commonly release copper ions into solutions, which contribute to their toxicity. We quantified the inhibitory effects of both copper oxide nanoparticles and copper sulfate on C. elegans toxicological endpoints to elucidate their biological effects. Several toxicological endpoints were analyzed in C. elegans, including nematode reproduction, feeding behavior, and average body length. We examined three wild C. elegans isolates together with the Bristol N2 laboratory strain to explore the influence of different genotypic backgrounds on the physiological response to copper challenge. All strains exhibited greater sensitivity to copper oxide nanoparticles compared to copper sulfate, as indicated by reduction of average body length and feeding behavior. Reproduction was significantly reduced only at the highest copper dose, though still more pronounced with copper oxide nanoparticles compared to copper sulfate treatment. Furthermore, we investigated the effects of copper oxide nanoparticles and copper sulfate on neurons, cells with known vulnerability to heavy metal toxicity. Degeneration of dopaminergic neurons was observed in up to 10% of the population after copper oxide nanoparticle exposure. Additionally, mutants in the divalent-metal transporters, smf-1 or smf-2, showed increased tolerance to copper exposure, implicating both transporters in copper-induced neurodegeneration. These results highlight the complex nature of CuO nanoparticle toxicity, in which a nanoparticle-specific effect was observed in some traits (average body length, feeding behavior) and a copper ion specific effect was observed for other traits (neurodegeneration, response to stress)

Defects in Mating Behavior and Tail Morphology Are the Primary Cause of Sterility in \u3cem\u3eCaenorhabditis elegans\u3c/em\u3e Males at High Temperature

Reproduction is a fundamental imperative of all forms of life. For all the advantages sexual reproduction confers, it has a deeply conserved flaw: it is temperature sensitive. As temperatures rise, fertility decreases. Across species, male fertility is particularly sensitive to elevated temperature. Previously, we have shown in the model nematode Caenorhabditis elegans that all males are fertile at 20°C, but almost all males have lost fertility at 27°C. Male fertility is dependent on the production of functional sperm, successful mating and transfer of sperm, and successful fertilization post-mating. To determine how male fertility is impacted by elevated temperature, we analyzed these aspects of male reproduction at 27°C in three wild-type strains of C. elegans: JU1171, LKC34 and N2. We found no effect of elevated temperature on the number of immature non-motile spermatids formed. There was only a weak effect of elevated temperature on sperm activation. In stark contrast, there was a strong effect of elevated temperature on male mating behavior, male tail morphology and sperm transfer such that males very rarely completed mating successfully when exposed to 27°C. Therefore, we propose a model where elevated temperature reduces male fertility as a result of the negative impacts of temperature on the somatic tissues necessary for mating. Loss of successful mating at elevated temperature overrides any effects that temperature may have on the germline or sperm cells

Device and method for converting direct current into alternate current

The device for converting direct current into alternate current comprises a multilevel converter associated with at least a source of direct current and a modulation unit having piloting means for piloting the converter for the conversion of the direct current into an alternate output current, in which the modulation unit comprises comparison means for comparing the output current value with a preset positive threshold value and a preset negative threshold value, the piloting means being suitable for piloting the converter with a pulse modulation of the unipolar type in the event of the output current value being above the positive threshold value or below the negative threshold value and with a pulse modulation of the complementary type in the event of the output current value being below the positive threshold value and above the negative threshold value. The method for converting direct current into alternate current comprises a piloting phase of a multilevel converter for the conversion of a direct voltage into an alternate output voltage, a comparison phase of the output current value with a preset positive threshold value and a preset negative threshold value, the piloting phase being suitable for piloting the converter with a pulse modulation of the unipolar type in the event of the output current value being above the positive threshold value or below the negative threshold value and with a pulse modulation of the complementary type in the event of the output current value being below the positive threshold value and above the negative threshold value

Gestational weight gain in overweight and obese women enrolled in a healthy lifestyle and eating habits program

OBJECTIVES: To determine whether changes in lifestyle in women with BMI > 25 could decrease gestational weight gain and unfavorable pregnancy outcomes. METHODS: Women with BMI > 25 were randomized at 1st trimester to no intervention or a Therapeutic Lifestyle Changes (TLC) Program including diet (overweight: 1700 kcal/day, obese: 1800 kcal/day) and mild physical activity (30 min/day, 3 times/week). At baseline and at the 36th week women filled-in a Food Frequency Questionnaire. OUTCOMES: gestational weight gain, gestational diabetes mellitus, gestational hypertension, preterm delivery. Data stratified by BMI categories. RESULTS: Socio-demographic features were similar between groups (TLC: 33 cases, CONTROLS: 28 cases). At term, gestational weight gain in obese women randomized to TLC group was lower (6.7 ± 4.3 kg) versus controls (10.1 ± 5.6 kg, p = 0.047). Gestational diabetes mellitus, gestational hypertension and preterm delivery were also significantly lower. TLC was an independent factor in preventing gestational weight gain, gestational diabetes mellitus, gestational hypertension. Significant changes in eating habits occurred in the TLC group, which increased the number of snacks, the intake of fruits-vegetables and decreased the consumption of sugar. CONCLUSIONS: A caloric restriction associated to changes in eating behavior and constant physical activity, is able to reduce gestational weight gain and related pregnancy complications in obese women.Objectives: To determine whether changes in lifestyle in women with BMI > 25 could decrease gestational weight gain and unfavorable pregnancy outcomes. Methods: Women with BMI > 25 were randomized at 1st trimester to no intervention or a Therapeutic Lifestyle Changes (TLC) Program including diet (overweight: 1700 kcal/day, obese: 1800 kcal/day) and mild physical activity (30 min/day, 3 times/week). At baseline and at the 36th week women filled-in a Food Frequency Questionnaire. Outcomes: gestational weight gain, gestational diabetes mellitus, gestational hypertension, preterm delivery. Data stratified by BMI categories. Results: Socio-demographic features were similar between groups (TLC: 33 cases, Controls: 28 cases). At term, gestational weight gain in obese women randomized to TLC group was lower (6.7 ± 4.3 kg) versus controls (10.1 ± 5.6 kg, p = 0.047). Gestational diabetes mellitus, gestational hypertension and preterm delivery were also significantly lower. TLC was an independent factor in preventing gestational weight gain, gestational diabetes mellitus, gestational hypertension. Significant changes in eating habits occurred in the TLC group, which increased the number of snacks, the intake of fruits-vegetables and decreased the consumption of sugar. Conclusions: A caloric restriction associated to changes in eating behavior and constant physical activity, is able to reduce gestational weight gain and related pregnancy complications in obese women. © 2014 Informa UK Ltd

Activation of NF-kappaB/Rel transcription factors in human primary peripheral blood mononuclear cells by interleukin 7.

Pathways that regulate the activation of NF-kappaB/Rel transcription factors are known to include signaling through a number of cytokine receptors. Interleukin 7 (IL-7), produced by bone marrow and other stromal cells, is a key factor for differentiation and survival in the lymphoid and other compartments. We found that human recombinant IL-7 induced NF-kappaB/Rel activation, analyzed by electrophoretic mobility shift assay (EMSA), in human peripheral blood T lymphocytes from healthy donors. Induced complexes included p65 and p50 NF-kappaB/Rel subunits. These results demonstrate for the first time that IL-7 can participate in signaling leading to NF-kappaB/Rel activation

Impact of leadership on the nursing workforce during the COVID-19 pandemic

Background The aim was to determine how the learning about protective factors from previous pandemics was implemented and the impact of this on nurses’ experience. Methods Secondary data analysis of semistructured interview transcripts exploring the barriers and facilitators to changes implemented to support the surge of COVID-19 related admissions in wave 1 of the pandemic. Participants represented three-levels of leadership: whole hospital (n=17), division (n=7), ward/department-level (n=8) and individual nurses (n=16). Interviews were analysed using framework analysis. Results Key changes that were implemented in wave 1 reported at whole hospital level included: a new acute staffing level, redeploying nurses, increasing the visibility of nursing leadership, new staff well-being initiatives, new roles created to support families and various training initiatives. Two main themes emerged from the interviews at division, ward/department and individual nurse level: impact of leadership and impact on the delivery of nursing care. Conclusions Leadership through a crisis is essential for the protective effect of nurses’ emotional well-being. While nursing leadership was made more visible during wave 1 of the pandemic and processes were in place to increase communication, system-level challenges resulting in negative experiences existed. By identifying these challenges, it has been possible to overcome them during wave 2 by employing different leadership styles to support nurse's well-being. Challenges and distress that nurses experience when making moral decisions requires support beyond the pandemic for nurse’s well-being. Learning from the pandemic about the impact of leadership in a crisis is important to facilitate recovery and lessen the impact in further outbreaks

Repression of Germline Genes in \u3cem\u3eCaenorhabditis elegans\u3c/em\u3e Somatic Tissues by H3K9 Dimethylation of Their Promoters

Repression of germline-promoting genes in somatic cells is critical for somatic development and function. To study how germline genes are repressed in somatic tissues, we analyzed key histone modifications in three Caenorhabditis elegans synMuv B mutants, lin-15B, lin-35, and lin-37—all of which display ectopic expression of germline genes in the soma. LIN-35 and LIN-37 are members of the conserved DREAM complex. LIN-15B has been proposed to work with the DREAM complex but has not been shown biochemically to be a member of the complex. We found that, in wild-type worms, synMuv B target genes and germline genes are enriched for the repressive histone modification dimethylation of histone H3 on lysine 9 (H3K9me2) at their promoters. Genes with H3K9me2 promoter localization are evenly distributed across the autosomes, not biased toward autosomal arms, as are the broad H3K9me2 domains. Both synMuv B targets and germline genes display a dramatic reduction of H3K9me2 promoter localization in lin-15B mutants, but much weaker reduction in lin-35 and lin-37mutants. This difference between lin-15B and DREAM complex mutants likely represents a difference in molecular function for these synMuv B proteins. In support of the pivotal role of H3K9me2 in regulation of germline genes by LIN-15B, global loss of H3K9me2 but not H3K9me3 results in phenotypes similar to synMuv B mutants, high-temperature larval arrest, and ectopic expression of germline genes in the soma. We propose that LIN-15B-driven enrichment of H3K9me2 at promoters of germline genes contributes to repression of those genes in somatic tissues