Modulation of immune responses by Plasmodium falciparum infection in asymptomatic children living in the endemic region of Mbita,western Kenya

Individuals living in malaria endemic areas become clinically immune after multiple re-infections over time and remain infected without apparent symptoms. However, it is unclear why a long period is required to gain clinical immunity to malaria, and how such immunity is maintained. Although malaria infection is reported to induce inhibition of immune responses, studies on asymptomatic individuals living in endemic regions of malaria are relatively scarce. We conducted a cross-sectional study of immune responses in asymptomatic school children aged 4–16 years living in an area where Plasmodium falciparum and Schistosoma mansoni infections are co-endemic in Kenya. Peripheral blood mononuclear cells were subjected to flow cytometric analysis and cultured to determine proliferative responses and cytokine production. The proportions of cellular subsets in children positive for P. falciparum infection at the level of microscopy were comparable to the negative children, except for a reduction in central memory-phenotype CD8⁺ T cells and natural killer cells. In functional studies, the production of cytokines by peripheral blood mononuclear cells in response to P. falciparum crude antigens exhibited strong heterogeneity among children. In addition, production of IL-2 in response to anti-CD3 and anti-CD28 monoclonal antibodies was significantly reduced in P. falciparum-positive children as compared to -negative children, suggesting a state of unresponsiveness. These data suggest that the quality of T cell immune responses is heterogeneous among asymptomatic children living in the endemic region of P. falciparum, and that the responses are generally suppressed by active infection with Plasmodium parasites.     

Understanding the Impact of Oligomeric Polystyrene Side Chain Arrangement on the All‐Polymer Solar Cell Performance

The introduction of oligomeric polystyrene (PS) side chains into the conjugated backbone is proven to enhance the processability and electronic properties of semiconducting polymers. Here, two series of donor and acceptor polymers are prepared with different molar percentages of PS side chains to elucidate the effect of their substitution arrangement on the all‐polymer solar cell performance. The observed device performance is lower when the PS side chains are substituted on the donor polymer and higher when on the acceptor polymer, indicating a clear arrangement effect of the PS side chain. The incorporation of PS side chains to the acceptor polymer contributes to the decrease in phase separation domain size in the blend films. However, the reduced domain size was still an order of magnitude larger than the typical exciton diffusion length. A detailed morphological study together with the estimation of solubility parameter of the pristine PS, donor, and acceptor polymers reveals that the relative value of solubility parameter of each component dominantly contributes to the purity of the phase separated domain, which strongly impacts the amount of generated photocurrent and overall solar cell performance. This study provides an understanding of the design strategies to improve the all‐polymer solar cells.     

Insights into wolf presence in human‐dominated landscapes: the relative role of food availability,humans and landscape attributes

Aim Understanding which human or environmental factors interact to enable or to limit the occurrence and persistence of large carnivores in human‐dominated landscapes is an important issue for their effective conservation, especially under the current scenario of global change where most of their former habitat is being transformed by humans. Location NW Iberian Peninsula. Methods We combine data on the distribution of Iberian wolves (Canis lupus signatus) living in a human‐dominated landscape in NW Spain and variation and partitioning methods to investigate the relative importance of three groups of predictors: food availability, humans and landscape attributes – each group expected to have unequal effects on wolf reproduction and survival – and their interactions on the occurrence of this species. Results We found that the group of predictors related with landscape attributes (altitude, roughness and refuge) strongly determined wolf occurrence, followed by humans and food availability. Variance partitioning analysis revealed that the three most important components determining wolf occurrence were related with landscape attributes: (1) the joint effects of the three predictor groups, (2) the joint effect of humans and landscape attributes and (3) the pure effect of landscape attributes. Altitude had the main independent contribution to explain the probability of wolf occurrence. Main conclusions In human‐dominated landscapes, the occurrence of wolves is the result of a complex interaction among several environmental and human factors. Our results suggest that the characteristics of the landscape (spatial context) – factors associated with the security of wolves facilitating that animals go unnoticed by humans, wolf movements, dispersal events and short‐time colonization – become more important in human‐dominated landscapes and may have played a key role in the occurrence and persistence of this species throughout decades modulating the relationship between humans and wolf distribution.     

Ectopic Osteoid and Bone Formation by Three Calcium-Phosphate Ceramics in Rats,Rabbits and Dogs

Calcium phosphate ceramics with specific physicochemical properties have been shown to induce de novo bone formation upon ectopic implantation in a number of animal models. In this study we explored the influence of physicochemical properties as well as the animal species on material-induced ectopic bone formation. Three bioceramics were used for the study: phase-pure hydroxyapatite (HA) sintered at 1200°C and two biphasic calcium phosphate (BCP) ceramics, consisting of 60 wt.% HA and 40 wt.% TCP (β-Tricalcium phosphate), sintered at either 1100°C or 1200°C. 108 samples of each ceramic were intramuscularly implanted in dogs, rabbits, and rats for 6, 12, and 24 weeks respectively. Histological and histomorphometrical analyses illustrated that ectopic bone and/or osteoid tissue formation was most pronounced in BCP sintered at 1100°C and most limited in HA, independent of the animal model. Concerning the effect of animal species, ectopic bone formation reproducibly occurred in dogs, while in rabbits and rats, new tissue formation was mainly limited to osteoid. The results of this study confirmed that the incidence and the extent of material-induced bone formation are related to both the physicochemical properties of calcium phosphate ceramics and the animal model.     

RADtyping: An Integrated Package for Accurate De Novo Codominant and Dominant RAD Genotyping in Mapping Populations

Genetic linkage maps are indispensable tools in genetic, genomic and breeding studies. As one of genotyping-by-sequencing methods, RAD-Seq (restriction-site associated DNA sequencing) has gained particular popularity for construction of high-density linkage maps. Current RAD analytical tools are being predominantly used for typing codominant markers. However, no genotyping algorithm has been developed for dominant markers (resulting from recognition site disruption). Given their abundance in eukaryotic genomes, utilization of dominant markers would greatly diminish the extensive sequencing effort required for large-scale marker development. In this study, we established, for the first time, a novel statistical framework for de novo dominant genotyping in mapping populations. An integrated package called RADtyping was developed by incorporating both de novo codominant and dominant genotyping algorithms. We demonstrated the superb performance of RADtyping in achieving remarkably high genotyping accuracy based on simulated and real mapping datasets. The RADtyping package is freely available at http://www2.ouc.edu.cn/mollusk/ detailen.asp?id=727.     

亚热带不同林分土壤矿质氮库及氮矿化速率的季节动态

以亚热带地区天然林、格氏栲人工林和杉木人工林为对象,采取PVC管原位培养连续取样法,对不同林分土壤净氨化速率、净硝化速率及净氮矿化速率进行为期一年(2014年9月—2015年8月)的研究,分析林分类型和季节动态对土壤矿质氮库和净氮矿化速率的影响.结果表明: 硝态氮是该地区土壤矿质氮库的主要存在形式,天然林和杉木人工林土壤硝态氮含量分别占总土壤矿质氮库的55.1%～87.5%和56.1%～79.1%,林分间土壤铵态氮含量差异不显著,硝态氮含量差异显著,其中格氏栲人工林土壤硝态氮含量显著低于天然林和杉木人工林.土壤硝态氮库和矿质氮库在不同月份间差异显著,在植物非生长季节(10月至次年2月)较大,在植物生长季节(3—9月)较小.各林分全年土壤净硝化速率均较低,净氨化速率是净氮矿化速率的主要存在形式,林分类型对土壤净氨化速率有显著影响,其中杉木人工林显著低于天然林和格氏栲人工林.月份对土壤净氨化速率有显著影响,各林分土壤净氨化速率变化规律不一致,但均在11月和2月达到一年中的最低值.重复测量方差分析显示,林分类型和季节动态对土壤矿质氮库及氮矿化速率均有显著影响.温度和水分是影响土壤矿质库及氮矿化速率的重要因素,凋落物对土壤氮矿化速率的影响主要是通过质量控制而非数量控制.     

Structural diversity in the extracellular faces of peptidergic G-protein-coupled receptors. Molecular cloning of the mouse C5a anaphylatoxin receptor.

The mouse C5a receptor gene was isolated using the human C5a receptor cDNA probe recently described (Gerard, N. P., and C. Gerard. 1991. Nature 349:614). By analogy with the human gene, the mouse homolog contains two exons with the 5' untranslated region and initiating methionine codon present in exon 1 and the remainder of the molecule in exon 2. Generation of an expressible cDNA for the mouse C5a receptor was accomplished using the polymerase chain reaction and a sense oligodeoxynucleotide primer which included an initiation codon just 5' to the sequence encoding the N-linked glycosylation site. When transfected into human 293 kidney epithelial cells the cloned cDNA directs expression of a binding site for human C5a anaphylatoxin with a binding constant of 2.5 +/- 0.3 nM; the human C5a receptor expressed under identical conditions has a Kd of 1.7 +/- 0.2 nM. Overall, the deduced amino acid sequences of the receptors are 65% identical given the analogous gene structures. Alignment of the sequences as seven transmembrane segment receptors reveals that the greatest structural diversity (approximately 70%) exists in the putative extracellular domains. In contrast, species differences among other members of this family of seven membrane-spanning receptors is generally only 10 to 20%, even for receptors whose ligands are relatively small and not expected to interact with sites on the extracellular surfaces. A high degree of structural identify is observed for the C5a receptors in the transmembrane segments and in all but one of the loops predicted to exist in the cytoplasm. Inasmuch as critical structures responsible for high affinity binding of the 74 amino acid polypeptide to both C5a receptors involve features conserved between species, these data provide the starting point for mutagenesis studies to determine the nature of the binding and activation sites for the chemotactic receptors. Additionally, these data provide a reagent for immunologic and molecular genetic studies on the role of C5a receptors in inflammatory models.     

心脏晶体停搏液和冷血停搏液不同灌注方法对心肌保护的评价

目的：评估二种心脏停搏液不同灌注方法对心肌保护作用。方法：30例双瓣患者随机分为冷晶体停搏液间断灌注组(n=10),冷血停搏液间断灌注组(n=10),冷血停搏液持续灌注组(n=10),观察血浆心肌肌钙蛋白T(CnT)、肌酸激酶(CK)、肌酸激酶同工酶(CK—MB)。结果：体外循环后冷晶体停搏液间断灌注组血浆心肌肌钙蛋白T和肌酸激酶、肌酶激酶同工酶较其他2组明显增高;冷血停搏液间断灌注组和冷血停搏液持续灌注组血浆心肌肌钙蛋白T、肌酸激酶、肌酸激酶同工酶无明显差异。结论：冷血停搏液的心肌保护优于冷晶体停搏液,冷血停搏液间断灌注与持续灌注没有明显差异。     

Exosomal microRNA-155-5p from PDLSCs regulated Th17/Treg balance by targeting sirtuin-1 in chronic periodontitis

The mechanism of local inflammation and systemic injury in chronic periodontitis is complicated, in which and exosomes play an important role. In our study, we found that T helper cell 17 (Th17)/regulatory T cell (Treg) balance is destabilized in the peripheral blood of patients with periodontitis, with upregulated Th17 or downregulated Treg, respectively. Porphyromonas gingivalis lipopolysaccharide (LPS) was used to simulate the inflammatory microenvironment of chronic periodontitis. The exosomes were extracted from periodontal ligament stem cells (PDLSCs) in LPS-induced periodontitis environment, which inversely effected on CD4+ T cells under normal and inflammatory conditions. Furthermore, compared with exosomes from normal PDLSCs, lower expression of microRNA-155-5p (miR-155-5p) and higher expression of Sirtuin-1 (SIRT1) were observed in exosomes from LPS-stimulated PDLSCs. Exosomes from PDLSCs alleviated inflammatory microenvironment through Th17/Treg/miR-155-5p/SIRT1 regulatory network. This study aimed to find the “switching” factors that affected the further deterioration of periodontitis to maximally control the multiple downstream damage signal factors to further understand periodontitis and find new targets for its treatment.     

Epigallocatechin gallate inhibits endothelial exocytosis

Consumption of green tea is associated with a decrease in cardiovascular mortality. The beneficial health effects of green tea are attributed in part to polyphenols, organic compounds found in tea that lower blood pressure, reduce body fat, decrease LDL cholesterol, and inhibit inflammation. We hypothesized that epigallocatechin gallate (EGCG), the most abundant polyphenol in tea, inhibits endothelial exocytosis, the initial step in leukocyte trafficking and vascular inflammation. To test this hypothesis, we treated human umbilical-vein endothelial cells with EGCG and other polyphenols, and then measured endothelial exocytosis. We found that EGCG decreases endothelial exocytosis in a concentration-dependent manner, with the effects most prominent after 4 h of treatment. Other catechin polyphenols had no effect on endothelial cells. By inhibiting endothelial exocytosis, EGCG decreases leukocyte adherence to endothelial cells. In searching for the mechanism by which EGCG affects endothelial cells, we found that EGCG increases Akt phosphorylation, eNOS phosphorylation, and nitric oxide (NO) production. NOS inhibition revealed that NO mediates the anti-inflammatory effects of EGCG. Our data suggest that polyphenols can decrease vascular inflammation by increasing the synthesis of NO, which blocks endothelial exocytosis.