Calculation of the Ionization Cross Sections for Ion – Atom Collision by Using the Cdw-Eis Model.

In this paper we calculate total cross sections for proton and alpha particle-impact ionization of neutral atoms  H , He, Ne and Ar for the energies ranging from 10keV to 10MeV.Also, we calculate theoretical singly, doubly differential ionization cross sections in collisions between proton particle and helium atoms at different impact energies. The provided theoretical model for the program user is based on quantum mechanical approximations which have proved to be very successful in the study of ionization in ion–atom collisions. is on continuum distorted-wave eikonal-initial-state (CDW-EIS) approximation. The results are in reasonable agreement with available experimental data

Differential sensitivity of regulatory and effector T cells to cell death: a prerequisite for transplant tolerance

Despite significant progress achieved in transplantation, immunosuppressive therapies currently used to prevent graft rejection are still endowed with severe side effects impairing their efficiency over the long term. Thus, the development of graft-specific, non toxic innovative therapeutic strategies has become a major challenge, the goal being to selectively target alloreactive effector T cells while sparing CD4+Foxp3+ regulatory T cells (Tregs) to promote operational tolerance. Various approaches, notably the one based on monoclonal antibodies or fusion proteins directed against the TCR/CD3 complex, TCR coreceptors, or costimulatory molecules, have been proposed to reduce the alloreactive T cell pool which is an essential prerequisite to create a therapeutic window allowing Tregs to induce and maintain allograft tolerance. In this minireview, we focus on the differential sensitivity of Tregs and effector T cells to the depleting and inhibitory effect of these immunotherapies, with a particular emphasis on CD3-specific antibodies that beyond their immunosuppressive effect, also express potent tolerogenic capacities

Learning from agriculture: understanding low-dose antimicrobials as drivers of resistome expansion

Antimicrobial resistance is a growing public health challenge worldwide, with agricultural use of antimicrobials being one major contributor to the emergence and dissemination of antimicrobial resistance. Globally, most antimicrobials are used in industrial food animal production, a major context for microbiomes encountering low-doses or subtherapeutic-levels of antimicrobial agents from all mechanistic classes. This modern practice exerts broad eco-evolutionary effects on the gut microbiome of food animals, which is subsequently transferred to animal waste. This waste contains complex constituents that are challenging to treat, including antimicrobial resistance determinants and low-dose antimicrobials. Unconfined storage or land deposition of a large volume of animal waste causes its wide contact with the environment and drives the expansion of the environmental resistome through mobilome facilitated horizontal genet transfer. The expanded environmental resistome, which encompasses both natural constituents and anthropogenic inputs, can persist under multiple stressors from agriculture and may re-enter humans, thus posing a public health risk to humans. For these reasons, this review focuses on agricultural antimicrobial use as a laboratory for understanding low-dose antimicrobials as drivers of resistome expansion, briefly summarizes current knowledge on this topic, highlights the importance of research specifically on environmental microbial ecosystems considering antimicrobial resistance as environmental pollution, and calls attention to the needs for longitudinal studies at the systems level

Proteomic analysis of differentially expressed proteins involved in peel senescence in harvested mandarin fruit

Mandarin (Citrus reticulata), a non-climacteric fruit, is an economically important fruit worldwide. The mechanism underlying senescence of non-climacteric fruit is poorly understood. In this study, a gel-based proteomic study followed by LC-ESI-MS/MS analysis was carried out to investigate the proteomic changes involved in peel senescence in harvested mandarin ‘Shatangju’ fruit stored for 18 d. Over the course of the storage period, the fruit gradually senesced, accompanied by a decreased respiration rate and increased chlorophyll degradation and disruption of membrane integrity. Sixty-three proteins spots that showed significant differences in abundance were identified. The up-regulated proteins were mainly associated with cell wall degradation, lipid degradation, protein degradation, senescence-related transcription factors, and transcription-related proteins. In contrast, most proteins associated with ATP synthesis and scavenging of reactive oxygen species were significantly down-regulated during peel senescence. Three thioredoxin proteins and three Ca2+ signaling-related proteins were significantly up-regulated during peel senescence. It is suggested that mandarin peel senescence is associated with energy supply efficiency, decreased antioxidant capability, and increased protein and lipid degradation. In addition, activation of Ca2+ signaling and transcription factors might be involved in cell wall degradation and primary or secondary metabolism

Propagule pressure, habitat conditions and clonal integration influence the establishment and growth of an invasive clonal plant, Alternanthera philoxeroides

Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules) may affect the establishment, growth and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments) or low (one fragment) propagule pressure was established either in bare soil (open habitat) or dense native vegetation of Jussiaea repens (vegetative habitat), with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions

Phorbol ester reduces ethanol excitation of dopaminergic neurons of the ventral tegmental area: Involvement of protein kinase C theta

Neurons of the ventral tegmental area (VTA) play a key role in the rewarding and reinforcing effects of drugs of abuse, including alcohol. Ethanol directly increases the firing rate of dopaminergic (DAergic) VTA neurons, but modulation of the firing rate of DAergic VTA neurons can be controlled by a number of factors, including some that are under the control of protein kinase C (PKC). Application of phorbol esters activates PKC and the present study assessed the effect of a phorbol ester, phorbol 12-myristate 13-acetate (PMA), on ethanol-induced excitation of DA VTA neurons. Ethanol-induced excitation of DAergic VTA neurons was reduced significantly in the presence of PMA. This action of PMA was antagonized by chelerythrine chloride, a non-selective antagonist of PKC, but not by moderate concentrations of antagonists of conventional PKC isoforms (Gö6976 and Gö6983). A PKC δ/θ inhibitor antagonized PMA-induced reduction of ethanol excitation. Since PKCδ antagonist Gö6983 did not antagonize the effect of PMA on ethanol excitation, the PMA reduction of ethanol excitation is most likely to be mediated by PKCθ. Antagonists of intracellular calcium pathways were ineffective in antagonizing PMA action on ethanol excitation, consistent with the lack of calcium dependence of PKCθ. In summary, ethanol-induced excitation of VTA neurons is attenuated in the presence of PMA, and this attenuation appears to be mediated by PKCθ. This novel mechanism for interfering with ethanol activation of reward-related neurons could provide a new target for pharmacotherapy to ameliorate alcoholism

Alternative splicing during Arabidopsis flower development results in constitutive and stage-regulated isoforms

Alternative splicing (AS) is a process in eukaryotic gene expression, in which the primary transcript of a multi-exon gene is spliced into two or more different mature transcripts, thereby increasing proteome diversity. AS is often regulated differentially between different tissues or developmental stages. Recent studies suggested that up to 60% of intron-containing genes in Arabidopsis thaliana undergo AS. Yet little is known about this complicated and important process during floral development. To investigate the preferential expression of different isoforms of individual alternatively spliced genes, we used high throughput RNA-Seq technology to explore the transcriptomes of three floral development stages of Arabidopsis thaliana and obtained information of various alternative splicing events. We identified approximately 24,000 genes that were expressed at one or more of these stages, and found that nearly 25% of multi-exon genes had two or more spliced variants. This is less frequent than the previously reported 40%~60% for multiple organs and stages of A. thaliana, indicating that many genes expressed in floral development function with a single predominant isoform. On the other hand, 1,716 isoforms were differentially expressed between the three stages, suggesting that AS might still play important roles in stage transition during floral development. Moreover, 337 novel transcribed regions were identified and most of them have a single exon. In addition, our analyses provide a comprehensive survey of alternative splicing in floral development and facilitate further genomic and genetic studies

Glycine cleavage powers photoheterotrophic growth of Chloroflexus aurantiacus in the absence of H2

Chloroflexus aurantiacus is an anoxygenic phototrophic bacterium. Its unique CO2 fixation pathway and primitive light-harvesting antenna complexes have attracted extensive research attentions. In this work, we investigated the photoheterotrophic growth of C. aurantiacus J-10-fl using acetate (at 55 oC and without H2(g)). The results indicate that glycine can promote anaerobic biomass production in a minimal medium by 3~5 folds. Via 13C-metabolite analysis, we observed that glycine was involved in serine synthesis. Instead of being used as a major carbon source, glycine was degraded to produce C1 units and NAD(P)H. Tracer experiments also suggest that photoheterotrophic cultures growing with a exogenous glycine source exhibited capabilities of assimilating CO2 via multiple routes (including the 3-hydroxypropionate pathway). Finally, glycylglycine, a commonly used culture buffer, could also release glycine via thermal or enzymatic degradation to significantly enhance photoheterotrophic growth of C. aurantiacus

Atypical modulation of distant functional connectivity by cognitive state in children with Autism Spectrum Disorders

We examined whether modulation of functional connectivity by cognitive state differed between pre-adolescent children with Autism Spectrum Disorders (ASD) and age and IQ-matched control children. Children underwent functional magnetic resonance imaging (fMRI) during two states, a resting state followed by a sustained attention task. A voxel-wise method was used to characterize functional connectivity at two levels, local (within a voxel’s 14 mm neighborhood) and distant (outside of the voxel’s 14 mm neighborhood to the rest of the brain) and regions exhibiting Group X State interaction were identified for both types of connectivity maps. Distant functional connectivity of regions in the left frontal lobe (dorsolateral [BA 11, 10]; supplementary motor area extending into dorsal anterior cingulate [BA 32/8]; and premotor [BA 6, 8, 9]), right parietal lobe (paracentral lobule [BA 6 ]; angular gyrus [BA 39/40]), and left posterior middle temporal cortex (BA 19/39) showed a Group X State interaction such that relative to the resting state, connectivity reduced (i.e., became focal) in control children but increased (i.e., became diffuse) in ASD children during the task state. Higher state-related increase in distant connectivity of left frontal and right angular gyrus predicted worse inattention in ASD children. Two graph theory measures (global efficiency and modularity) were also sensitive to Group X State differences, with the magnitude of state-related change predicting inattention in the ASD children. Our results indicate that as ASD children transition from an unconstrained to a sustained attentional state, functional connectivity of frontal and parietal regions with the rest of the brain becomes more widespread in a manner that may be maladaptive as it was associated with attention problems in everyday life