microRNA‐124 inhibits stem‐like properties and enhances radiosensitivity in nasopharyngeal carcinoma cells via direct repression of expression of JAMA

Cancer stem cells (CSCs) are a source of tumour recurrence in patients with nasopharyngeal carcinoma (NPC); however, the function of microRNA‐124 (miR‐124) in NPC CSCs has not been clearly defined. In this study, we investigated the role of miR‐124 in NPC CSCs. qRT‐PCR was performed to measure miR‐124 expression in NPC tissues and cell lines and the effects of miR‐124 on stem‐like properties and radiosensitivity of NPC cells measured. Luciferase reporter assays and rescue experiments were used to investigate the interaction of miR‐124 with the 3′UTR of junctional adhesion molecule A (JAMA). Finally, we examined the effects of miR‐124 in an animal model and clinical samples. Down‐regulation of miR‐124 was detected in cancer tissues and was inversely associated with tumour stage and lymph node metastasis. Overexpression of miR‐124 inhibited stemness properties and enhanced radiosensitivity of NPC cells in vitro and in vivo via targeting JAMA. Up‐regulation of miR‐124 was correlated with superior overall survival of patients with NPC. Our study demonstrates that miR‐124 can inhibit stem‐like properties and enhance radiosensitivity by directly targeting JAMA in NPC. These findings provide novel insights into the molecular mechanisms underlying therapy failure in NPC.     

ClSnRK2.3 negatively regulates watermelon fruit ripening and sugar accumulation

Watermelon(Citrullus lanatus) as non-climacteric fruit is domesticated from the ancestors with inedible fruits. We previously revealed that the abscisic acid(ABA) signaling pathway gene ClSnRK2.3 might infuence watermelon fruit ripening. However,the molecular mechanisms are unclear. Here,we found that the selective variation of ClSnRK2.3 resulted in lower promoter activity and gene expression level in cultivated watermelons than ancestors, which indicated ClSnRK2.3 might be a negative regulator ...     

Ecotoxicity evaluation of PFBSK for the whole environmental compartments and comprehensive comparison of hazard and risk to PFOS

A series of perfluorobutane sulfonate (PFBS)-related substances are produced as the alternatives to corresponding perfluorooctane sulfonate (PFOS). However, there is little reliable information about PFBS available for the whole ecotoxicology compartments. At present, its ecotoxicity of perfluorobutane sulfonate potassium (PFBSK) was selected as a typical PFBS chemical to investigate and evaluate its aquatic, terrestrial, microorganism and sediment toxicity according to the Organization for Economic Cooperation and Development (OECD) guideline under the framework of the REACH regulation. Meanwhile, the ecotoxicology hazard and risk for PFBSK and PFOS were compared comprehensively.

PFBSK did not show acute and chronic aquatic, microorganisms and terrestrial animal toxicity, while exhibited some terrestrial plants toxicity. The ecotoxicology of PFBSK decreased sharply except for terrestrial plants compared with PFOS. Especially, for acute and chronic aquatic ecotoxicity, PFBSK is lower than 100 times those of PFOS.

Although the similar terrestrial plants toxicity level was observed for PFBSK and PFOS, the lower risk of PFBSK was deduced for the reason that there was far less chances to be exposed and retained in the soil and sediment for its high water solubility and low adsorption.

In conclusion, PFBSK showed lower ecotoxicity hazard and risk than those of PFOS. PFBSK could be an environmental friendly alternative to PFOS.     

小球藻病毒PBCV-1特异性溶壁酶(Lysin)的溶壁活性

从PBCV－1感染小球藻NC64A的细胞裂解液中提取了Lysin的粗制剂,酶活底物范围分析表明,几丁质酶、壳聚糖酶的β-1,3-葡萄糖苷酶是Lysin活性的主要组成部分,并与小球藻细胞壁的组成甩分相吻合。其中几丁酯酶和壳聚糖酶,特别是几丁酯酶在裂解小球藻细胞壁的过程中发挥了重要的作用。Lysin粗制剂经FPLC分离纯化得到分子量分别为52kD、56kD的两个几丁质酶（Chil和Chi2）和一个分子量为36kD的壳聚糖酶。     

17β-雌二醇对延迟着床期小鼠子宫内膜基质细胞内钙的快速调节效应

本文旨在研究17β-雌二醇(17β-estradiol,E2)对延迟着床期小鼠子宫内膜基质细胞内钙振荡的影响和机制,探讨E2对着床期子宫内膜基质细胞是否存在非基因组快速作用.实验的第一部分,小鼠分为6组,每组4只,即0.1%二甲基亚砜(dimethylsulfoxide,DMSO)对照组、1×10-8mol/L牛血清白蛋白(bovine serum albumin,BSA)对照组、1×10-8mol/L E2组、1×10-8mol/L E2-BSA组、1×10-8mol/L E2 无钙液组、1×10-8mol/L E2 5μg/mL他莫西芬(tamoxifen)组.急性分离延迟着床小鼠孕第7天子宫内膜基质细胞,应用激光共聚焦显微镜技术实时检测各组基质细胞[Ca2 ]I的变化.实验的第二部分,分离7只延迟着床小鼠孕第7天子宫内膜基质细胞,用免疫荧光法检测1×10-8mol/L E2作用前和作用后5 min、15 min、30min细胞内磷酸化磷脂酶C(phospholipase C,PLC)的变化.基质细胞[Ca2 ]I的变化结果显示,在E2,E2-BSA和E2 无钙液组中[Ca2 ];均明显升高,15 min达到高峰,随后下降回到基础值.但DMSO和BSA组中[Ca2 ]I未见明显变化;加入传统雌激素胞浆受体阻断剂tamoxifen不能抑制E2引起的[Ca2 ]I升高.免疫荧光结果显示,加入1×10-8mol/L E2后,PLC的磷酸化水平升高,15 min达高峰(P<0.001),然后逐渐下降回到基础值.结果提示,E2对延迟着床小鼠子宫内膜基质细胞[Ca2 ]I的变化具有快速调节效应,该作用可能是通过非基因组途径实现的,与磷酸化PLC信号途径有关.     

西双版纳种子植物物种多样性的垂直格局及机制

物种多样性海拔分布格局及其形成机制的研究是生物地理学和宏观生态学的重要议题之一。本文利用西双版纳植物专著资料, 结合高分辨率的地形和气候等数据, 探讨了面积、边界限制和现代气候对西双版纳野生种子植物物种丰富度及物种密度海拔分布格局的影响。结果表明: (1)物种丰富度呈单峰分布格局, 面积(81.9%)、边界限制(17.5%)和气候(60.0-69.3%)都不同程度地解释了物种丰富度的单峰格局; (2)利用幂函数种-面积关系计算的物种密度沿海拔大致呈减小的分布趋势, 气候的解释率降低为32.6-40.6%, 与边界限制无显著相关关系; (3)利用等面积高度带划分得到的物种密度沿海拔呈单峰变化趋势, 物种密度与边界限制无显著相关性, 但气候对物种密度的解释率为81.6-89.9%。研究结果有助于准确全面地理解物种多样性的海拔分布格局及其成因机制, 为西双版纳生物多样性保护提供理论支撑和实践指导。     

金针菇退化菌丝的生理生化特征

【背景】金针菇菌种在继代培养的过程中会出现菌种退化的现象,影响着金针菇的产量与质量。【目的】为研究金针菇退化菌种菌丝的生理生化特征,筛选金针菇退化菌株。【方法】以金针菇原始菌株(H)和退化菌株(T)为研究对象,测定不同碳源培养基上菌丝的生理生化特征及超氧化物歧化酶(SuperoxideDismutase,SOD)、过氧化物酶(Peroxidase,POD)和过氧化氢酶(Catalase,CAT)的活性,并测定菌丝在栽培瓶中的漆酶(Laccase,Lac)和锰过氧化物酶(ManganesePeroxidase,MnP)的活性,记录菌丝在搔菌后的恢复情况。【结果】T在各个碳源的菌丝生长速度低于H,粉孢子等级在3-4级之间,SOD、CAT活性低于H,在栽培料中的Lac活性和MnP活性在第5天时与H相同,在第10、15、20天低于H。T在搔菌后菌丝恢复时间比H恢复时间长,恢复后的菌丝长势没有H长势浓密。【结论】通过探究金针菇原始菌株与退化菌株的菌丝生理生化特征,为判断金针菇菌株是否为退化菌株提供理论依据。