High levels of diversity and population structure in the potato late blight pathogen at the Mexico centre of origin

Globally destructive crop pathogens often emerge by migrating out of their native ranges. These pathogens are often diverse at their centre of origin and may exhibit adaptive variation in the invaded range via multiple introductions from different source populations. However, source populations are generally unidentified or poorly studied compared to invasive populations. Phytophthora infestans, the causal agent of late blight, is one of the most costly pathogens of potato and tomato worldwide. Mexico is the centre of origin and diversity of P. infestans and migration events out of Mexico have enormously impacted disease dynamics in North America and Europe. The debate over the origin of the pathogen, and population studies of P. infestans in Mexico, has focused on the Toluca Valley, whereas neighbouring regions have been little studied. We examined the population structure of P. infestans across central Mexico, including samples from Michoacán, Tlaxcala and Toluca. We found high levels of diversity consistent with sexual reproduction in Michoacán and Tlaxcala and population subdivision that was strongly associated with geographic region. We determined that population structure in central Mexico has contributed to diversity in introduced populations based on relatedness of U.S. clonal lineages to Mexican isolates from different regions. Our results suggest that P. infestans exists as a metapopulation in central Mexico, and this population structure could be contributing to the repeated re‐emergence of P. infestans in the United States and elsewhere.     

Mibefradil improves beta-adrenergic responsiveness and intracellular Ca(2+) handling in hypertrophied rat myocardium

The present study investigated the effects of mibefradil, a novel T-type channel blocker, on ventricular function and intracellular Ca(2+) handling in normal and hypertrophied rat myocardium. Ca(2+) transient was measured with the bioluminescent protein, aequorin. Mibefradil (2 microM) produced nonsignificant changes in isometric contraction and peak systolic intracellular Ca(2+) concentration ([Ca(2+)](i)) in normal rat myocardium. Hypertrophied papillary muscles isolated from aortic-banded rats 10 weeks after operation demonstrated a prolonged duration of isometric contraction, as well as decreased amplitudes of developed tension and peak Ca(2+) transient compared with the sham-operated group. Additionally, diastolic [Ca(2+)](i) increased in hypertrophied rat myocardium. The positive inotropic effect of isoproterenol stimulation was blunted in hypertrophied muscles despite a large increase in Ca(2+) transient amplitude. Afterglimmers and corresponding aftercontractions were provoked with isoproterenol (10(-5) and 10(-4) M) stimulation in 4 out of 16 hypertrophied muscles, but were eliminated in the presence of mibefradil (2 microM). In addition, hypertrophied muscles in the presence of mibefradil had a significant improvement of contractile response to isoproterenol stimulation and a reduced diastolic [Ca(2+)](I), although a mild decrease of peak Ca(2+)-transient was also shown. However, verapamil (2 microM) did not restore the inotropic and Ca(2+) modulating effects of isoproterenol in hypertrophied myocardium. Mibefradil partly restores the positive inotropic response to beta-adrenergic stimulation in hypertrophied myocardium from aortic-banded rats, an effect that might be useful in hypertrophied myocardium with impaired [Ca(2+)](i) homeostasis.     

Allergenic pollen plants and their influential factors in urban areas

Owing to unsuitable green space construction, abundant allergenic pollen plants are centralized in urban areas, producing allergenic pollen. A mass of airborne allergenic pollen could cause pollinosis to badly influence people's robustness. To provide scientific basis for reasonable green space construction, the research advances of allergenic plants were reviewed. Firstly, species composition, phenological characteristics and influential factors (which include unsuitable green land construction, urban heat island effect, traffic pollution, etc.) were summarized. Secondly, the strategies controlling allergenic pollen plants were proposed. Thirdly, some problems on allergenic plants worthy of more research, including allergenic mechanism and methodology, were also put forward.     

CD146 acts as a novel receptor for netrin-1 in promoting angiogenesis and vascular development

Angiogenesis, a process that newly-formed blood vessels sprout from pre-existing ones, is vital for vertebrate development and adult homeostasis. Previous studies have demonstrated that the neuronal guidance molecule netrin-1 participates in angiogenesis and morphogenesis of the vascular system. Netrin-1 exhibits dual activities in angiogenesis: either promoting or inhibiting angiogenesis. The anti-angiogenic activity of netrin-1 is mediated by UNC5B receptor. However, how netrin-1 promotes angiogenesis remained unclear. Here we report that CD146, an endothelial transmembrane protein of the immunoglobulin superfamily, is a receptor for netrin-1. Netrin-1 binds to CD146 with high affinity, inducing endothelial cell activation and downstream signaling in a CD146-dependent manner. Conditional knockout of the cd146 gene in the murine endothelium or disruption of netrin-CD146 interaction by a specific anti-CD146 antibody blocks or reduces netrin-1-induced angiogenesis. In zebrafish embryos, downregulating either netrin-1a or CD146 results in vascular defects with striking similarity. Moreover, knocking down CD146 blocks ectopic vascular sprouting induced by netrin-1 overexpression. Together, our data uncover CD146 as a previously unknown receptor for netrin-1 and also reveal a functional ligand for CD146 in angiogenesis, demonstrating the involvement of netrin-CD146 signaling in angiogenesis during vertebrate development.     

Allergenic pollen plants and their influential factors in urban areas

Owing to unsuitable green space construction, abundant allergenic pollen plants are centralized in urban areas, producing allergenic pollen. A mass of airborne allergenic pollen could cause pollinosis to badly influence people's robustness. To provide scientific basis for reasonable green space construction, the research advances of allergenic plants were reviewed. Firstly, species composition, phenological characteristics and influential factors (which include unsuitable green land construction, urban heat island effect, traffic pollution, etc.) were summarized. Secondly, the strategies controlling allergenic pollen plants were proposed. Thirdly, some problems on allergenic plants worthy of more research, including allergenic mechanism and methodology, were also put forward.     

RUV-III-NB: normalization of single cell RNA-seq data

Normalization of single cell RNA-seq data remains a challenging task. The performance of different methods can vary greatly between datasets when unwanted factors and biology are associated. Most normalization methods also only remove the effects of unwanted variation for the cell embedding but not from gene-level data typically used for differential expression (DE) analysis to identify marker genes. We propose RUV-III-NB, a method that can be used to remove unwanted variation from both the cell embedding and gene-level counts. Using pseudo-replicates, RUV-III-NB explicitly takes into account potential association with biology when removing unwanted variation. The method can be used for both UMI or read counts and returns adjusted counts that can be used for downstream analyses such as clustering, DE and pseudotime analyses. Using published datasets with different technological platforms, kinds of biology and levels of association between biology and unwanted variation, we show that RUV-III-NB manages to remove library size and batch effects, strengthen biological signals, improve DE analyses, and lead to results exhibiting greater concordance with independent datasets of the same kind. The performance of RUV-III-NB is consistent and is not sensitive to the number of factors assumed to contribute to the unwanted variation.     

肺细胞色素氧化酶体视学测量法在高压氧研究中的应用

采用超微结构细胞化学方法,用计算机图象分析仪测量计算了小鼠肺毛细血管和Ⅱ型肺泡线粒体、线粒体膜和嵴上细胞色素氧化酶活性变化的二维形态学、三维立体学定量参数。结果表明,毛细血管线粒体面积较Ⅱ型肺泡细胞小,但体密度却大;毛细血管线粒体细胞色素氧化酶阳性反应面积比正型肺泡细胞小,但酶反应体密度却大、暴露于高压氧（０．５ＭＰａ）后小鼠Ⅱ型肺泡细胞线粒体细胞色素氧化酶活性降低。     

Anti-breast cancer sinomenine derivatives via mechanisms of apoptosis induction and metastasis reduction

Sinomenine, a morphinane-type isoquinoline-derived alkaloid, was first isolated from stems and roots of Sinomenium diversifolius (Miq.) in 1920. Later discovery by researchers confirmed various essential biological efficacy sinomenine exerted in vitro and in vivo. In this study, a series of 15 sinomenine/furoxan hybrid compounds were designed and synthesised in search of a TNBC drug candidate. Some of the target compounds exhibited strong antiproliferative activities against cancer cell lines, especially for TNBC cells, compared to positive controls. Among them, hybrid 7Cc exerted superior cytotoxic effects on cancer cell lines with exceptionally low IC₅₀ (0.82 μM) against MDA-MB-231 cells with the highest safety index score. Further studies in mechanism displayed that 7Cc could induce an S phase cell cycle arrest, stimulate apoptosis in MDA-MB-231 cells, disrupt mitochondrial membrane potential and exert a genotoxic effect on DNA in cancer cells. In addition, 7Cc also notably inhibited MDA-MB-231 cells in both migration, invasion and adhesion.