Origin and timing of de novo variants implicated in type 2 von Willebrand disease

Very few studies have shown the real origin and timing of de novo variants (DNV) implicated in von Willebrand disease (VWD). We investigated four families with type 2 VWD. First, we conducted linkage analysis using single nucleotide variant genotyping to recognize the possible provenance of DNV. Second, we performed amplification refractory mutation system‐quantitative polymerase chain reaction to confirm the real origin of variant (~0% mutant cells) or presence of a genetic mosaic variant (0%–50% mutant cells) in three embryonic germ layer‐derived tissues and sperm cells. Then, three possible timings of DNV were categorized based on the relative likelihood of occurrence according to the number of cell divisions during embryogenesis. Two each with type 2B VWD (proband 1 p.Arg1308Cys, proband 4 p.Arg1306Trp) and type 2A VWD (proband 2 p.Leu1276Arg, proband 3 p.Ser1506Leu) were identified. Variant origins were identified for families 1, 2 and 3 and confirmed to originate from the mother, father and father, respectively. However, the father of family 4 was confirmed to have isolated germline mosaicism with 2.2% mutant sperm cells. Further investigation confirmed the paternal grandfather to be the origin of variant. Thus, we proposed that DNV originating from the two fathers most likely occurred at the single sperm cell, the one originating from the mother occurred at the zygote during the first few cellular divisions; alternatively, in family 4, the DNV most likely occurred at the early postzygotic development in the father. Our findings are essential for understanding genetic pathogenesis and providing accurate genetic counselling.     

Establishment of a five‐enzalutamide‐resistance‐related‐gene‐based classifier for recurrence‐free survival predicting of prostate cancer

To identify prostate cancer (PCa) patients with a high risk of recurrence is critical before delivering adjuvant treatment. We developed a classifier based on the Enzalutamide treatment resistance‐related genes to assist the currently available staging system in predicting the recurrence‐free survival (RFS) prognosis of PCa patients. We overlapped the DEGs from two datasets to obtain a more convincing Enzalutamide‐resistance‐related‐gene (ERRG) cluster. The five‐ERRG‐based classifier obtained good predictive values in both the training and validation cohorts. The classifier precisely predicted RFS of patients in four cohorts, independent of patient age, pathological tumour stage, Gleason score and PSA levels. The classifier and the clinicopathological factors were combined to construct a nomogram, which had an increased predictive accuracy than that of each variable alone. Besides, we also compared the differences between high‐ and low‐risk subgroups and found their differences were enriched in cancer progression‐related pathways. The five‐ERRG‐based classifier is a practical and reliable predictor, which adds value to the existing staging system for predicting the RFS prognosis of PCa after radical prostatectomy, enabling physicians to make more informed treatment decisions concerning adjuvant therapy.     

Cell delivery systems: Toward the next generation of cell therapies for type 1 diabetes

Immunoprotection and oxygen supply are vital in implementing a cell therapy for type 1 diabetes (T1D). Without these features, the transplanted islet cell clusters will be rejected by the host immune system, and necrosis will occur due to hypoxia. The use of anti‐rejection drugs can help protect the transplanted cells from the immune system; yet, they also may have severe side effects. Cell delivery systems (CDS) have been developed for islet transplantation to avoid using immunosuppressants. CDS provide physical barriers to reduce the immune response and chemical coatings to reduce host fibrotic reaction. In some CDS, there is architecture to support vascularization, which enhances oxygen exchange. In this review, we discuss the current clinical and preclinical studies using CDS without immunosuppression as a cell therapy for T1D. We find that though CDS have been demonstrated for their ability to support immunoisolation of the grafted cells, their functionality has not been fully optimized. Current advanced methods in clinical trials demonstrate the systems are partly functional, physically complicated to implement or inefficient. However, modifications are being made to overcome these issues.     

Parasite reliance on its host gut microbiota for nutrition and survival

Studying the microbial symbionts of eukaryotic hosts has revealed a range of interactions that benefit host biology. Most eukaryotes are also infected by parasites that adversely affect host biology for their own benefit. However, it is largely unclear whether the ability of parasites to develop in hosts also depends on host-associated symbionts, e.g., the gut microbiota. Here, we studied the parasitic wasp Leptopilina boulardi (Lb) and its host Drosophila melanogaster. Results showed that Lb successfully develops in conventional hosts (CN) with a gut microbiota but fails to develop in axenic hosts (AX) without a gut microbiota. We determined that developing Lb larvae consume fat body cells that store lipids. We also determined that much larger amounts of lipid accumulate in fat body cells of parasitized CN hosts than parasitized AX hosts. CN hosts parasitized by Lb exhibited large increases in the abundance of the bacterium Acetobacter pomorum in the gut, but did not affect the abundance of Lactobacillus fructivorans which is another common member of the host gut microbiota. However, AX hosts inoculated with A. pomorum and/or L. fructivorans did not rescue development of Lb. In contrast, AX larvae inoculated with A. pomorum plus other identified gut community members including a Bacillus sp. substantially rescued Lb development. Rescue was further associated with increased lipid accumulation in host fat body cells. Insulin-like peptides increased in brain neurosecretory cells of parasitized CN larvae. Lipid accumulation in the fat body of CN hosts was further associated with reduced Bmm lipase activity mediated by insulin/insulin-like growth factor signaling (IIS). Altogether, our results identify a previously unknown role for the gut microbiota in defining host permissiveness for a parasite. Our findings also identify a new paradigm for parasite manipulation of host metabolism that depends on insulin signaling and the gut microbiota.Subject terms: Animal physiology, Microbial ecology     

生态效率视角下旅游业生态福利及驱动因素——以常州市为例

经济效益最大化与环境影响最小化是绿色旅游与可持续发展的内在诉求。本文立足于生态效率模型,创新性地提出旅游业生态福利指数,据此分析1995—2017年常州市旅游业生态福利变化趋势及驱动效应,旨在为评价旅游产业绿色可持续发展能力提供新视角。研究发现:(1)1995年来常州市生态足迹呈现先增长后下降趋势,但旅游业各部门生态足迹均不断增长,游客人均资源消耗约为本地居民人均资源消耗的2.81—9.37倍,面临艰巨的节能减排压力。(2)1995年来常州市本底生态效率与旅游生态效率逐年提升,分别增加了37033元/hm²和44226元/hm²;同等资源消耗下,旅游业平均每单位产出高14409元/hm²,但游客年均消耗的自然资源却为本地居民的5.78倍。(3)1995—2007年间常州市旅游生态福利升降波动频繁,2007年来呈以直线式地骤降,受规模效益影响,旅游业的绿色生态福利和高效性不断弱化,为全市的资源节约量下降了10.7倍。(4)迪氏对数指标分解法(Logarithmic Mean Disivia Index, LMDI)揭示规模...     

人乳铁蛋白(hLF)转基因山羊的遗传背景分析

以随机整合方式获得的转基因动物外源基因的拷贝数、整合位点及染色体核型等遗传背景并不清楚,可能会存在外源基因的沉默整合、无效整合、毒性整合以及其表达水平不可预测等问题。文中选取了6只原代(F0)及其相对应的子一代(F1)的人乳铁蛋白(hLF)转基因山羊作为研究对象,分别颈静脉采血、提取DNA,通过染色体核型分析、实时荧光定量PCR(qPCR)、ELISA和Westernblotting等检测技术,研究其外源基因的遗传背景与表达水平。结果显示,6只F0代转基因山羊的染色体没有明显的形态变异、数量改变等异常情况。相对拷贝数高低不同(2–16),且能够稳定地遗传给下一代,F0和F1代hLF基因拷贝数一致。F1代转基因山羊表达hLF水平最高可达1.12 g/L(L3-1,拷贝数8)。结果表明,整合的外源基因能够稳定地遗传下一代,也没有对转基因山羊个体的生长发育造成障碍,而且拷贝数高低与hLF表达水平无明显的相关性,这为转基因山羊及其他转基因动物的新品种培育奠定了基础,解析了遗传背景。     

基因编辑技术发展现状

鉴于以CRISPR/Cas9为代表的基因编辑技术在可操作性、经济性和时效性上取得的革命性突破,以及国内外对此技术的研发和应用现状,中国有可能在基因编辑技术的下游技术研发(特别是植物基因编辑的应用)、专业公司孵化等方面取得突破。因此分析目前中国基因编辑技术发展的关键需求、潜在应用领域就显得尤为迫切和必要。采用问卷调查和计量方法对基因编辑技术发展的关键技术需求和最潜在应用领域进行研究。首先建立有序多分类Logistic回归模型并进行因变量分析,通过显著性检验在4个方面共24个问卷问题中选择8个存在显著因果关系的自变量,然后基于有序多分类Logistic回归模型,分析8个问题中不同选项对基因编辑技术发展的具体影响作用。调查结果表明多数基因编辑领域的研究人员认为在注重基因编辑基础技术研发的同时应更多地关注如何进行技术产业化,要注重在植物领域发展潜在竞争优势;促进我国基因编辑技术发展不仅需要科研机构参与,更需要包括高校、政府在内的多方力量协同作用;正确引导公众的基因编辑技术舆论认识和建立安全规范体系较为迫切;技术风险规避的重点应放在生物武器和生物恐怖、基因编辑相关传染病、物种基因改变对生态环境的...     

ABC转运蛋白及其在合成生物学中的应用

ABC转运蛋白(ATP-binding cassette transporter,ABC transporter)作为一种超大膜转运蛋白家族,在大多数生物体中发挥着重要作用。文中从结构特征、转运机制以及生理功能等方面论述了ABC转运蛋白的研究进展,进而着重综述了近些年来ABC转运蛋白在合成生物学领域中的应用,并为今后进一步的研究提出了展望,希望为扩展其应用提供指导。