过氧化物酶体增殖物激活受体y (peroxisome proliferator activated receptorγ,PPARγ)辅助激活因子1α (PPARγ coactivator-lα,PGC-lα)作为一个重要的转录激活因子,参与多种生理活动的调节.本研究探究了PGC-1α在斑马鱼(Danio rerio) ZF4细胞(胚胎发育3d成纤维样细胞)冷应激过程中所起的作用.通过慢病毒质粒转染干扰PGC-1α基因的表达,并用嘌呤霉素筛选得到稳转细胞系,给与其18℃7d和10℃7d的低温刺激后使用CM-H2DCFDA探针染色,通过流式细胞仪检测细胞内活性氧(reactive oxygen species,ROS)含量;JC-1探针染色,流式细胞仪检测低温处理后PGC-1α敲降的细胞线粒体膜电位的变化.研究表明,在低温刺激下,PGC-1α基因未敲降的ZF4细胞内ROS含量升高,线粒体膜电位下降;而在PGC-1α基因敲降的ZF4细胞内,ROS含量在前者的水平上进一步升高,线粒体膜电位的下降也加剧,故PGC-1α在ZF4细胞冷应激过程中对细胞起到保护作用,能维持细胞内ROS含量和线粒体膜电位水平.本研究对PGC-1α基因在斑马鱼ZF4细胞冷应激过程中所起的功能进行初步探究,为鱼类在低温下的适应性研究提供依据.

[目的]了解罗氏沼虾亲虾越冬时循环养殖系统对水质的调控效果,探明其中微生物群落的作用.[方法]采集循环养殖系统运行88 d后的越冬池池水、池中人工水草(普通纤维膜)以及外置式生物滤器中的纳米纤维膜等3种不同基质上的微生物,利用DNA抽提、PCR扩增和定量以及高通量MiSeq测序技术等对3种不同基质上的微生物进行16S rRNA基因序列V4-V5区的测定和分析,并根据测序得到的双端测序读长(Pair-end reads)进行质量控制和过滤,之后进行操作分类单元(OTU)聚类分析,并基于OTU对微生物群落的多样性指数和群落结构进行分析;每3-4 d对越冬池池水水质进行监测.[结果]养殖池塘的水质保持在良好的状态,其中氨氮和亚硝氮浓度控制在0.17+0.08 mg/L和0.28±0.15 mg/L;不同基质上的微生物组成和多样性都不相同.在3种基质上共检测并鉴定出细菌64种,隶属于9门64属,包括变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、绿弯菌门(Chloroflexi)、厚壁菌门(Firmicutes)、浮霉菌门(Planctomycetes)、硝化螺旋菌门(Nitrospirae)、酸杆菌门(Acidobacteria)和绿菌门(Chlorobi).从属水平上对3种基质上的细菌进行分析,发现养殖池水中含量最高的为丛毛单菌科下的一个未分类类群(Comamonadaceae unclassified),其也是3种基质的共有优势类群;普通纤维膜上为Inhella,纳米纤维膜上则是小纺锤状菌属(Fusibacter).3种基质上细菌群落多样性顺序为:纳米纤维膜＞普通纤维膜＞养殖池水.通过对亲虾越冬养殖全过程的水质监测,发现越冬期间亲虾池水质始终保持在良好状态,并且在循环水系统开启约40 d后水质达到了相对稳定的状态.[结论]通过在育苗池中悬挂人工水草,配合内含纳米纤维膜的外置式生物滤器,可使罗氏沼虾越冬亲虾池保持良好的水质.随着新型材料科学的发展,开发出适用于水产养殖业的滤料很有必要.

Although it has been reported that autophagy is required for organisms surviving various unfavorable environmental conditions,the detailed role of autophagy under cold stress is still unclear.In this study,we investigated the role of autophagy under cold stress in HeLa cells (human cervical adenocarcinoma cells).A putative autophagosome marker EGFP-LC3 (enhanced green fluorescent protein-microtubule-associated protein 1A/1B-light chain 3) was used to monitor the process of autophagy in HeLa cells cultured at 37 ℃ (control) or cold stress conditions (10,8,28 ℃).The results showed that cold stress caused autophagy in HeLa cells in time-and temperaturedependent manners:substantial autophagosome accumulation was observed during 3-6 h at 10 ℃,while the most significant autophagy was detected after 3 d at 18℃,and only very low level of autophagosome formation was observed at 28 ℃.Further study showed that HeLa cells underwent decreased cell viability following the turnover of autophagosome,and Bafilomycin A1 treatment enhanced cold stress-induced decrease of cell viability,indicating a protective role of autophagy in HeLa cells against cold stress.Bafilomycin A1 treatment also enhanced cold stress-induced production of intracellular production of reactive oxygen species (ROS),indicating the involvement of ROS in the protective function of autophagy under cold stress.Our data suggested the essential role of autophagy in HeLa cells under cold stress.

2014年4月中下旬，笔者接到江苏泗洪县曹庙乡一养殖户报告其养殖的河蟹出现烂肢病，经现场诊断与实验室检验，确定了病原种类。现将具体情况简单介绍如下，以供养殖户参考。