Brain plasticity and cognitive functions after ethanol consumption in C57BL/6J mice

Acute or chronic administrations of high doses of ethanol in mice are known to produce severe cognitive deficits linked to hippocampal damage. However, we recently reported that chronic and moderate ethanol intake in C57BL/6J mice induced chromatin remodeling within the Bdnf promoters, leading to both enhanced brain-derived neurotrophic factor (BDNF) expression and hippocampal neurogenesis under free-choice protocol. We performed here a series of cellular and behavioral studies to analyze the consequences of these modifications. We showed that a 3-week chronic free-choice ethanol consumption in C57BL/6J mice led to a decrease in DNA methylation of the Bdnf gene within the CA1 and CA3 subfields of the hippocampus, and upregulated hippocampal BDNF signaling pathways mediated by ERK, AKT and CREB. However, this activation did not affect long-term potentiation in the CA1. Conversely, ethanol intake impaired learning and memory capacities analyzed in the contextual fear conditioning test and the novel object recognition task. In addition, ethanol increased behavioral perseveration in the Barnes maze test but did not alter the mouse overall spatial capacities. These data suggested that in conditions of chronic and moderate ethanol intake, the chromatin remodeling leading to BDNF signaling upregulation is probably an adaptive process, engaged via epigenetic regulations, to counteract the cognitive deficits induced by ethanol

Theory and particle tracking simulations of a resonant radiofrequency deflection cavity in TM110_{110} mode for ultrafast electron microscopy

We present a theoretical description of resonant radiofrequency (RF) deflecting cavities in TM$_{110}$ mode as dynamic optical elements for ultrafast electron microscopy. We first derive the optical transfer matrix of an ideal pillbox cavity and use a Courant-Snyder formalism to calculate the 6D phase space propagation of a Gaussian electron distribution through the cavity. We derive closed, analytic expressions for the increase in transverse emittance and energy spread of the electron distribution. We demonstrate that for the special case of a beam focused in the center of the cavity, the low emittance and low energy spread of a high quality beam can be maintained, which allows high-repetition rate, ultrafast electron microscopy with 100 fs temporal resolution combined with the atomic resolution of a high-end TEM. This is confirmed by charged particle tracking simulations using a realistic cavity geometry, including fringe fields at the cavity entrance and exit apertures

Application of relativistic scattering theory of x rays to diffraction anomalous fine structure in Cu

We apply our recent first-principles formalism of magnetic scattering of circularly polarized x rays to a single Cu crystal. We demonstrate the ability of our formalism to interpret the crystalline environment related near-edge fine structure features in the resonant x-ray scattering spectra at the Cu K absorption edge. We find good agreement between the computed and measured diffraction anomalous fine structure features of the x-ray scattering spectra

Storage, fertilization and cost properties highlight the potential of dried microbial biomass as organic fertilizer

The transition to sustainable agriculture and horticulture is a societal challenge of global importance. Fertilization with a minimum impact on the environment can facilitate this. Organic fertilizers can play an important role, given their typical release pattern and production through resource recovery. Microbial fertilizers (MFs) constitute an emerging class of organic fertilizers and consist of dried microbial biomass, for instance produced on effluents from the food and beverage industry. In this study, three groups of organisms were tested as MFs: a high-rate consortium aerobic bacteria (CAB), the microalgaArthrospira platensis('Spirulina') and a purple non-sulfur bacterium (PNSB)Rhodobactersp. During storage as dry products, the MFs showed light hygroscopic activity, but the mineral and organic fractions remained stable over a storage period of 91 days. For biological tests, a reference organic fertilizer (ROF) was used as positive control, and a commercial organic growing medium (GM) as substrate. The mineralization patterns without and with plants were similar for all MFs and ROF, with more than 70% of the organic nitrogen mineralized in 77 days. In a first fertilization trial with parsley, all MFs showed equal performance compared to ROF, and the plant fresh weight was even higher with CAB fertilization. CAB was subsequently used in a follow-up trial with petunia and resulted in elevated plant height, comparable chlorophyll content and a higher amount of flowers compared to ROF. Finally, a cost estimation for packed GM with supplemented fertilizer indicated that CAB and a blend of CAB/PNSB (85%/15%) were most cost competitive, with an increase of 6% and 7% in cost compared to ROF. In conclusion, as bio-based fertilizers, MFs have the potential to contribute to sustainable plant nutrition, performing as good as a commercially available organic fertilizer, and to a circular economy

Synchrotron Studies of the First-Order Melting Transitions of Hexatic Monolayers and Multilayers in Freely Suspended Liquid-Crystal Films

Synchrotron x-ray diffraction has been used to study the surface and the interior hexatic-to-liquid (smectic-I to smectic-C) melting transitions of freely suspended liquid-crystal films of N-[4'-(n-heptyl)benzylidene]-4-(n-heptyl)aniline (7O.7) five molecular layers thick. Both the surface hexatic monolayers and the interior hexatic layers melt via hysteretic first-order transitions. After the two surface layers undergo a first-order transition to the smectic-I phase, the surface hexatic correlation length $\xi$ evolves smoothly from $\sim 100 to \sim 300 \mathring{A}$ with a roughly square-root form, $\xi \sim \mid T-T_c \mid ^{1/2}$.Engineering and Applied Science

Genomic Diversity and Evolution of Mycobacterium ulcerans Revealed by Next-Generation Sequencing

Mycobacterium ulcerans is the causative agent of Buruli ulcer, the third most common mycobacterial disease after tuberculosis and leprosy. It is an emerging infectious disease that afflicts mainly children and youths in West Africa. Little is known about the evolution and transmission mode of M. ulcerans, partially due to the lack of known genetic polymorphisms among isolates, limiting the application of genetic epidemiology. To systematically profile single nucleotide polymorphisms (SNPs), we sequenced the genomes of three M. ulcerans strains using 454 and Solexa technologies. Comparison with the reference genome of the Ghanaian classical lineage isolate Agy99 revealed 26,564 SNPs in a Japanese strain representing the ancestral lineage. Only 173 SNPs were found when comparing Agy99 with two other Ghanaian isolates, which belong to the two other types previously distinguished in Ghana by variable number tandem repeat typing. We further analyzed a collection of Ghanaian strains using the SNPs discovered. With 68 SNP loci, we were able to differentiate 54 strains into 13 distinct SNP haplotypes. The average SNP nucleotide diversity was low (average 0.06–0.09 across 68 SNP loci), and 96% of the SNP locus pairs were in complete linkage disequilibrium. We estimated that the divergence of the M. ulcerans Ghanaian clade from the Japanese strain occurred 394 to 529 thousand years ago. The Ghanaian subtypes diverged about 1000 to 3000 years ago, or even much more recently, because we found evidence that they evolved significantly faster than average. Our results offer significant insight into the evolution of M. ulcerans and provide a comprehensive report on genetic diversity within a highly clonal M. ulcerans population from a Buruli ulcer endemic region, which can facilitate further epidemiological studies of this pathogen through the development of high-resolution tools

Distribution of Mycobacterium ulcerans in Buruli Ulcer Endemic and Non-Endemic Aquatic Sites in Ghana

Mycobacterium ulcerans, the causative agent of Buruli ulcer, is an emerging environmental bacterium in Australia and West Africa. The primary risk factor associated with Buruli ulcer is proximity to slow moving water. Environmental constraints for disease are shown by the absence of infection in arid regions of infected countries. A particularly mysterious aspect of Buruli ulcer is the fact that endemic and non-endemic villages may be only a few kilometers apart within the same watershed. Recent studies suggest that aquatic invertebrate species may serve as reservoirs for M. ulcerans, although transmission pathways remain unknown. Systematic studies of the distribution of M. ulcerans in the environment using standard ecological methods have not been reported. Here we present results from the first study based on random sampling of endemic and non-endemic sites. In this study PCR-based methods, along with biofilm collections, have been used to map the presence of M. ulcerans within 26 aquatic sites in Ghana. Results suggest that M. ulcerans is present in both endemic and non-endemic sites and that variable number tandem repeat (VNTR) profiling can be used to follow chains of transmission from the environment to humans. Our results suggesting that the distribution of M. ulcerans is far broader than the distribution of human disease is characteristic of environmental pathogens. These findings imply that focal demography, along with patterns of human water contact, may play a major role in transmission of Buruli ulcer

Three Essential Ribonucleases—RNase Y, J1, and III—Control the Abundance of a Majority of Bacillus subtilis mRNAs

Bacillus subtilis possesses three essential enzymes thought to be involved in mRNA decay to varying degrees, namely RNase Y, RNase J1, and RNase III. Using recently developed high-resolution tiling arrays, we examined the effect of depletion of each of these enzymes on RNA abundance over the whole genome. The data are consistent with a model in which the degradation of a significant number of transcripts is dependent on endonucleolytic cleavage by RNase Y, followed by degradation of the downstream fragment by the 5′–3′ exoribonuclease RNase J1. However, many full-size transcripts also accumulate under conditions of RNase J1 insufficiency, compatible with a model whereby RNase J1 degrades transcripts either directly from the 5′ end or very close to it. Although the abundance of a large number of transcripts was altered by depletion of RNase III, this appears to result primarily from indirect transcriptional effects. Lastly, RNase depletion led to the stabilization of many low-abundance potential regulatory RNAs, both in intergenic regions and in the antisense orientation to known transcripts