Gut microbiome in gastrointestinal cancer: a friend or foe?

The impact of the gut microbiome on host health is becoming increasingly recognized. To date, there is growing evidence that the complex characteristics of the microbial community play key roles as potential biomarkers and predictors of responses in cancer therapy. Many studies have shown that altered commensal bacteria lead to cancer susceptibility and progression in diverse pathways. In this review, we critically assess the data for gut microbiota related to gastrointestinal cancer, including esophageal, gastric, pancreatic, colorectal cancer, hepatocellular carcinoma and cholangiocarcinoma. Importantly, the underlying mechanisms of gut microbiota involved in cancer occurrence, prevention and treatment are elucidated. The purpose of this review is to provide novel insights for applying this understanding to the development of new therapeutic strategies in gastrointestinal cancer by targeting the microbial community.     

民勤绿洲边缘积沙带植物群落健康分析

甘肃河西走廊经过60多年的防沙治沙,在绿洲边缘形成了一条积沙带。其中,民勤绿洲边缘积沙带相对最典型、最完整。积沙带上的植被不仅是积沙带的形成因素,更是维持积沙带稳定的重要因素。从一定意义上说,积沙带上植被的健康状况,决定着积沙带的稳定性。为了分析积沙带上的植被状况,在民勤绿洲边缘积沙带上等间距设定了11条样线,通过60多个样方的植被调查,对民勤绿洲边缘积沙带上植物群落进行了健康序列分析。结果表明:民勤绿洲边缘积沙带上的植被普遍是不健康的,民勤绿洲边缘人工固沙林积沙带上的植被健康状况相对好于天然灌丛积沙带上的植被健康状况,乔灌混交林积沙带上的植被健康状况最差。民勤绿洲下游积沙带上的优势种植物柽柳严重枯死,健康状况最差,积沙带潜在风蚀活化的危险。农田弃耕后,沙区农田边缘防护林及其积沙带的保护是一个新的值得考虑的问题。     

基于NGS的染色质测序在肿瘤研究中的应用

染色质是真核生物细胞核内由核酸和蛋白质组成的复合结构,有着精密且复杂的三维结构。染色质除基本的DNA序列外,内部还存在着不同化学修饰,DNA-蛋白质相互作用,DNA-DNA相互作用和DNA-RNA相互作用,以上这些若发生改变都可能在肿瘤发生发展过程中起到至关重要的作用。通过不同的染色质测序方法,可以解析出这些改变,并进一步加深研究者对肿瘤形成机制的理解,最终应用于肿瘤的治疗。本文对常见的染色质测序技术部分原理和应用进行综述。     

ER-lysosome lipid transfer protein VPS13C/PARK23 prevents aberrant mtDNA-dependent STING signaling

Mutations in VPS13C cause early-onset, autosomal recessive Parkinson’s disease (PD). We have established that VPS13C encodes a lipid transfer protein localized to contact sites between the ER and late endosomes/lysosomes. In the current study, we demonstrate that depleting VPS13C in HeLa cells causes an accumulation of lysosomes with an altered lipid profile, including an accumulation of di-22:6-BMP, a biomarker of the PD-associated leucine-rich repeat kinase 2 (LRRK2) G2019S mutation. In addition, the DNA-sensing cGAS-STING pathway, which was recently implicated in PD pathogenesis, is activated in these cells. This activation results from a combination of elevated mitochondrial DNA in the cytosol and a defect in the degradation of activated STING, a lysosome-dependent process. These results suggest a link between ER-lysosome lipid transfer and innate immune activation in a model human cell line and place VPS13C in pathways relevant to PD pathogenesis.     

新疆苦豆子根瘤菌的数值分类研究

苦豆子(Sophora alopecuroides)对于干旱荒漠地区的畜牧业发展有着非常重要的意义,其生长特性与根瘤菌有密切关系。我们对分离自新疆苦豆子根瘤的67株根瘤菌及36个模式菌株进行了118项表型性状的测定,包括唯一碳源利用、唯一氮源利用、对抗生素和染料的抗性、耐盐性、初始pH值生长范围、生长温度范围及石蕊牛奶反应、氧化酶、过氧化氢酶和脲酶。对测定结果用聚类分析方法进行了分析,获得数值分类树状图。结果表明：新疆苦豆子根瘤菌在碳氮源利用、抗生素敏感性以及对染料的抗性程度等方面存在着差异。新疆苦豆子根瘤菌能耐受低温,并具有较强的耐盐、碱能力,所有供试菌株均能在初始pH值为9－12的YMA培养基上生长,92.5％的菌株能耐受3.0％的NaCl,91.0％的菌株能耐受4.0％的NaCl,有18株菌甚至能耐受5.0％和6.0％的NaCl。聚类结果表明, 在84.8%的相似性水平上,67个供试菌株构成了4个新的表观群,第Ⅰ、Ⅱ、Ⅲ、Ⅳ类群分别有21、7、4、3个菌株,中心菌株分别为NWBC152、NWTKX101、NWYJS12、NWLP112。此外,数值分类结果还表明,苦豆子根瘤菌与模式菌株的相似性较低,它们所形成的4个独立群可能有新种出现。     

Changes in the Chlorophyll Content and Cytokinin Levels in the Top Three Leaves of New Plant Type Rice During Grain Filling

This paper reports the ways that the differences in leaf senescence are related to grain filling, grain yield, and the dynamics of cytokinins (CKs) in the top three leaves of four field-grown new plant type (NPT) rice, a tropical japonica developed at the International Rice Research Institute, Philippines, to increase the yield potential of rice. The chlorophyll content in leaves decreased from flowering to maturity in all the NPT lines, whereas the grain filling percentage was higher in the fast-senescing NPT line than in slow-senescing NPT line. Grain yield was positively correlated with senescence in the flag leaf. Rapid changes in the CK levels were recorded in the leaves of the fast-senescing line, whereas the CK levels were relatively stable in leaves of the slow-senescing line, suggesting that the dynamics of CKs in the fast-senescing line are vital for fast senescence. There were no significant changes in bioactive CKs, CK O-glucosides (storage CKs), and cis-zeatin derivatives in different leaves of the slow-senescing NPT line between 0 and 3 weeks after flowering, suggesting that the content of these CKs is relatively stable during grain filling. A progressive increase in levels of bioactive CKs was positively correlated with gradual accumulation of CK N-glucosides (inactive CKs) in the top three leaves of the slow-senescing NPT line, whereas the decrease of bioactive CKs in the flag leaf of the fast-senescing line was accompanied by accumulation of CK O-glucosides. These results suggest that there is a higher rate of biosynthesis and/or import of bioactive CKs as well as their turnover which may favor delay of leaf senescence in the slow-senescing NPT line.     

供水及间甲酚对小麦间作蚕豆土壤微生物多样性和酶活性的影响

通过盆栽试验,探讨供水(田间持水量的45%、60%和75%)和化感物质间甲酚对小麦、蚕豆不同种植模式生长盛期土壤微生物多样性和酶活性的影响.结果表明,随灌水水平的降低,不同处理的土壤细菌、真菌和放线菌数量随之减少,间甲酚可加剧灌水减少引起的微生物数量的减少;间甲酚对不同处理土壤微生物多样性指数均具有降低作用,提高灌水水平可缓解间甲酚对间作群体土壤微生物多样性的负效应,但间甲酚在75%灌水水平下对单作微生物多样性的负效应最大,45%的供水水平和间甲酚作用下间作可维持更高的土壤微生物多样性.间甲酚对土壤过氧化氢酶的化感作用不显著,对脲酶和酸性磷酸酶活性的化感作用显著;3种土壤酶活性随供水水平的降低均显著下降,但供水与间甲酚、种植模式的互作效应对酶活性的影响不显著;间作对土壤过氧化氢酶和酸性磷酸酶活性具有极显著影响.