A Century of Research on Mammalian Male Germ Cell Meiotic Differentiation In Vitro

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Detection of the pediocin gene pedA in strains from human faeces by real-time PCR and characterization of Pediococcus acidilactici UVA1

<p>Abstract</p> <p>Background</p> <p>Bacteriocin-producing lactic acid bacteria are commonly used as natural protective cultures. Among them, strains of the genus <it>Pediococcus </it>are particularly interesting for their ability to produce pediocin, a broad spectrum antimicrobial peptide with a strong antagonistic activity against the food-borne pathogen <it>Listeria monocytogenes</it>. Furthermore, there is increasing interest in isolating new bacteriocin-producing strains of human intestinal origin that could be developed for probiotic effects and inhibition of pathogenic bacteria in the gut. In this work, we typed a new strain, co-isolated from baby faeces together with a <it>Bifidobacterium thermophilum </it>strain, and characterized its proteinaceous compound with strong antilisterial activity.</p> <p>Results</p> <p>The newly isolated strain UVA1 was identified as a <it>Pediococcus acidilactici </it>by carbohydrate fermentation profile, growth at 50°C and 16S rDNA sequencing. The partially purified bacteriocin was heat resistant up to 100°C, active over a wide range of pH (2 to 9) and susceptible to proteolytic enzymes. The molecular weight, estimated by SDS-PAGE, was similar to that of pediocin AcH/PA-1 (4.5 kDa). <it>P. acidilactici </it>UVA1 harboured a 9.5-kb plasmid that could be cured easily, which resulted in the loss of the antimicrobial activity. Southern hybridization using the DIG-labelled <it>pedA</it>-probe established that the bacteriocin gene was plasmid-borne as for all pediocin described so far. Nucleotide sequence of the whole operon (3.5 kb) showed almost 100 % similarity to the pediocin AcH/PA-1 operon. The mRNA transcript for <it>pedA </it>could be detected in <it>P. acidilactici </it>UVA1 but not in the cured derivative, confirming the expression of the <it>pedA</it>-gene in UVA1. Using a new real-time PCR assay, eleven out of seventeen human faecal samples tested were found to contain <it>pedA</it>-DNA.</p> <p>Conclusion</p> <p>We identified and characterised the first pediocin produced by a human intestinal <it>Pediococcus acidilactici </it>isolate and successfully developed a new real-time PCR assay to show the large distribution of <it>pedA</it>-containing strains in baby faecal samples.</p

Semi-automated calibration method for modelling of mountain permafrost evolution in Switzerland

Permafrost is a widespread phenomenon in mountainous regions of the world such as the European Alps. Many important topics such as the future evolution of permafrost related to climate change and the detection of permafrost related to potential natural hazards sites are of major concern to our society. Numerical permafrost models are the only tools which allow for the projection of the future evolution of permafrost. Due to the complexity of the processes involved and the heterogeneity of Alpine terrain, models must be carefully calibrated, and results should be compared with observations at the site (borehole) scale. However, for large-scale applications, a site- specific model calibration for a multitude of grid points would be very time-consuming. To tackle this issue, this study presents a semi-automated calibration method using the Generalized Likelihood Uncertainty Estimation (GLUE) as implemented in a 1-D soil model (CoupModel) and applies it to six permafrost sites in the Swiss Alps. We show that this semi-automated calibration method is able to accurately reproduce the main thermal condition characteristics with some limitations at sites with unique conditions such as 3-D air or water circulation, which have to be calibrated manually. The calibration obtained was used for global and regional climate model (GCM/RCM)-based long-term climate projections under the A1B climate scenario (EU-ENSEMBLES project) specifically downscaled at each borehole site. The projection shows general permafrost degradation with thawing at 10 m, even partially reaching 20 m depth by the end of the century, but with different timing among the sites and with partly considerable uncertainties due to the spread of the applied climatic forcing

The pesticide methoxychlor given orally during the perinatal/juvenile period, reduced the spermatogenic potential of males as adults by reducing their Sertoli cell number

Perinatal and juvenile oral treatment of rats with the insecticide, methoxychlor (MXC), reduced testicular size and other reproductive indices including the number of epididymal spermatozoa in those animals as adults [6]. The objective was to determine if these males exposed during development had fewer Sertoli cells which might explain these testicular effects. Rat dams were gavaged with MXC at 0, 5, 50, or 150 mg.kg(-1).day(-1) for the week before and after they gave birth. Resulting male pups (15/group) then were dosed directly from postnatal day 7 to 42. Testes were fixed in Bouin's and in OsO4, embedded in Epon and sectioned at 0.5 mum, stained with toluidine blue, and evaluated stereologically or cut at 20 mm to measure Sertoli cell nuclei with Nomarski optics. Sertoli cell number was calculated as the volume density of the nucleus times the parenchymal weight (90% of testicular weight) divided by the volume of a single Sertoli cell nucleus. Across dose groups, there were no changes in the nuclear volume density, the volume of a single nucleus, or the number of Sertoli cells per g parenchyma. There were highly significant dose-related changes in the volume of Sertoli cell nuclei per testis and the number of Sertoli cells per testis. Reduced testicular weight (r = 0.94) and reduced numbers of epididymal spermatozoa (r = 0.43) were significantly (p < 0.01) correlated to reduced number of Sertoli cells per testis. Hence, perinatal and juvenile oral exposure to MXC can reduce spermatogenic potential of males as adults by reducing their number of Sertoli cells

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

Etude in vitro de la différenciation de la lignée spermatogénétique chez le rat

TOURS-BU Sciences Pharmacie (372612104) / SudocSudocFranceF