Bacteria abundance and diversity of different life stages of Plutella xylostella (Lepidoptera: Plutellidae), revealed by bacteria culture‐dependent and PCR‐DGGE methods

Microbial abundance and diversity of different life stages (fourth instar larvae, pupae and adults) of the diamondback moth, Plutella xylostella L., collected from field and reared in laboratory, were investigated using bacteria culture‐dependent method and PCR‐DGGE analysis based on the sequence of bacteria 16S rRNA V3 region gene. A large quantity of bacteria was found in all life stages of P. xylostella. Field population had higher quantity of bacteria than laboratory population, and larval gut had higher quantity than pupae and adults. Culturable bacteria differed in different life stages of P. xylostella. Twenty‐five different bacterial strains were identified in total, among them 20 strains were presented in larval gut, only 8 strains in pupae and 14 strains in adults were detected. Firmicutes bacteria, Bacillus sp., were the most dominant species in every life stage. 15 distinct bands were obtained from DGGE electrophoresis gel. The sequences blasted in GenBank database showed these bacteria belonged to six different genera. Phylogenetic analysis showed the sequences of the bacteria belonged to the Actinobacteri, Proteobacteria and Firmicutes. Serratia sp. in Proteobacteria was the most abundant species in larval gut. In pupae, unculturable bacteria were the most dominant species, and unculturable bacteria and Serratia sp. were the most dominant species in adults. Our study suggested that a combination of molecular and traditional culturing methods can be effectively used to analyze and to determine the diversity of gut microflora. These known bacteria may play important roles in development of P. xylostella.     

降钙素基因相关肽参与运动诱导的心脏保护作用

目的：探讨降钙素基因相关肽（CGRP）在运动诱导的心脏保护中的作用和机制。方法：64只健康雄性SD大鼠随机分为4组（n=16）,经耐力训练和力竭运动后,观察心肌CGRP的分布与表达、血清心肌肌钙蛋白I（cTnI）、心肌缺血低氧改变、心肌NO、SOD、MDA的变化。结果：TG心肌CGRP免疫反应和SOD总活性较CG显著增强,TEG和EG组CGRP免疫反应减弱,SOD总活性降低,MDA增加,且EG组血清心肌肌钙蛋白I显著升高,心肌出现明显的缺血低氧改变,NO含量下降。结论：CGRP参与耐力训练诱导的心脏保护作用,与上调SOD活性、促进NO合成有关。     

Melatonin Regulates the Viability and Differentiation of Rat Midbrain Neural Stem Cells

(1) Neurogenesis driven by neural stem cells (NSCs) is regulated by physiological and pathological factors. Melatonin (MT) has profound neurotrophic and neuroprotective effects. Hence, we studied the role of MT in regulating the viability and differentiation of NSCs derived from rat ventral midbrain. (2) NSCs were isolated from the rat ventral midbrain. The viability of NSCs was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-ulfophenyl)-2H-tetrazolium assay. The differentiation of NSCs was examined by analyzing the expression of the neural markers, MT receptors, brain derived neurotropic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) with semi-quantitative RT-PCR, immunofluorescence cytochemistry, and Western blot. (3) Our results showed that MT could promote the viability of NSCs. In addition, MT could significantly elevate the mRNA and protein levels of tyroxine hydroxylase (TH), a marker of dopaminergic neurons, and decrease the expression of the astrocytes maker glial fibrillary acidic protein (GFAP). MT also increased the production of BDNF and GDNF in the cultured NSCs. Meanwhile, we first found that two subtypes of MT receptors, MT1 and MT2, were expressed in the ventral midbrain NSCs. (4) These results demonstrated that MT could induce NSCs to differentiate into dopaminergic neurons and decrease astrocyte production. These findings also suggest that MT could offer a beneficial tool in guiding directional differentiation of NSCs.     

ETA基因作为荧光定量PCR靶基因设计TaqMan探针快速检测铜绿假单胞菌的研究

铜绿假单胞菌是临床上常见致病菌, 传统的检测方法有各种弊端。本研究对该细菌的ETA基因用生物信息学方法加以分析, 选取相对保守且高度特异的DNA序列, 设计一对特异性引物和一个TaqMan探针, 建立FQ-PCR (fluorescence quantitative PCR)检测PA的方法。通过对梯度浓度的铜绿假单胞菌基因组DNA样品进行FQ-PCR检测和对多种细菌的DNA进行扩增, 来检测其灵敏度和验证引物和探针的特异性。试验结果表明, 对比现有的检测方法, 以ETA基因为靶基因, 基于TaqMan探针的快速FQ-PCR检测技术有更高的灵敏度和更好的特异性等优点, 具有很好的研究价值和应用前景。     

Expression studies of neogenin and its ligand hemojuvelin in mouse tissues.

Juvenile hemochromatosis is a severe hereditary iron overload disease caused by mutations in the HJV (hemojuvelin) and HAMP (hepcidin) genes. Hepcidin is an important iron regulatory hormone, and hemojuvelin may regulate hepcidin synthesis via the multifunctional membrane receptor neogenin. We explored the expression of murine hemojuvelin and neogenin mRNAs and protein. Real-time RT-PCR analysis of 18 tissues from male and female mice was performed to examine the mRNA expression profiles. To further study protein expression and localization we used immunohistochemistry on several tissues from three mouse strains. Mouse Neo1 mRNA was detectable in the 18 tissues tested, the highest signals being evident in the ovary, uterus, and testis. Neogenin protein was observed in the brain, skeletal muscle, heart, liver, stomach, duodenum, ileum, colon, renal cortex, lung, testis, ovary, oviduct, and uterus. The spleen, thymus, and pancreas were negative for neogenin. The highest signals for Hjv mRNA were detectable in the skeletal muscle, heart, esophagus, and liver. The results indicate that Neo1 mRNA is widely expressed in both male and female mouse tissues with the highest signals detected in the reproductive system. Moreover, Hjv and Neo1 mRNAs are simultaneously expressed in skeletal muscle, heart, esophagus, and liver.     

原子力显微镜对人羊膜间充质干细胞成脂分化的观察

观察人羊膜间充质干细胞(human amniotic mesenchymal stem cells,hAMSCs)成脂分化前后超微结构及其机械性能的变化,以期进一步了解hAMSCs在体外成脂分化的过程。用流式细胞仪分析细胞表面分子表达情况,油红O染色检测hAMSCs成脂分化情况,原子力显微镜观察(AFM)分化前后超微结构及机械性能的变化等。结果显示,流式细胞检测显示,CD34,CD45,HLA-DR,呈阴性表达,CD29,CD90呈阳性表达;油红O染色可见脂肪细胞胞质中有大小不等的圆性红色脂肪滴;AFM观察诱导后的hAMSCs表面有脂滴状的颗粒,粘弹力增大,硬度减小。运用AFM可以清晰观察到诱导前后形貌及机械性能变化。     

细菌内依赖TonB的外膜铁转运体的研究进展

铁是细菌所必需的微量营养元素,但由于易被氧化溶解性低,生物体的利用率大大降低。细菌在进化过程中形成多种策略来吸收环境中低浓度的铁,不同类型铁的吸收通过外膜上依赖TonB的转运体(TonB-dependent transporters,TBDTs)完成,TBDTs结合不同形式的铁复合物,通过内膜上的TonB-ExbB-ExbD复合物提供能量完成转运,对其机制的研究一直是微生物基础生命活动研究中的热点问题。近年来新鉴定了一些TBDTs的结构,并对其功能和转运机制有了更深入的研究,对此进行了综述,不仅有助于进一步揭示细菌的铁转运机制,而且有助于寻找新的靶位点以开发新的治疗药物。     

Changes and subcellular localizations of the enzymes involved in phenylpropanoid metabolism during grape berry development

The phenylpropanoid pathway yields a variety of phenolics that are closely associated with fruit qualities in addition to structural and defense-related functions. However, very little has been reported concerning its metabolism in fruit. This experiment was designed to assess changes of eleven phenolic acids in grape berry (Vitis vinifera L. cv. Cabernet Sauvignon) and explore both the activities and amounts of three key enzymes--phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-coumarate:coenzyme A ligase (4CL)--catalyzing the biosynthesis of these compounds during berry development. Finally, the subcellular localizations of the enzymes within berry tissues were also investigated using immuno-gold electron microscopic technique. The results indicated that the contents of gallic, protocatechuic, gentisic and caffeic acid all changed drastically during berry development, while other compounds containing p-hydroxybenzoic, vanillic, syringic, chlorogenic, p-coumaric, ferulic and sinapic acid varied only slightly. Activities of PAL, C4H and 4CL showed similar pattern changes with two accumulated peaks throughout berry development. In addition, their activities all showed a highly positive correlation with the total contents of phenolic acids, whereas the immunoblotting analysis showed that changes in enzyme activities were independent of the enzyme amounts. Results from the subcellular-localization study revealed that PAL was mainly present in the cell walls, secondarily thickened walls, and the parenchyma cells of the berry mesocarp cells, C4H was found primarily in the chloroplast (plastid) and nucleus and 4CL predominantly in the secondarily thickened walls and the parenchyma cells of mesocarp vascular tissue.     

海马锥体神经元树突中电压依赖性钾通道研究进展

海马锥体神经元树突上分布着多种电压依赖性钾离子通道,但这些通道在胞体和树突不同部位的分布密度以及在突触电活动中的功能意义各不相同。倒传递动作电位（b-AP）和兴奋性突触后电位（EPSP）是树突中常见的功能电信号。本文简要介绍了近年来海马锥体神经元树突上这些钾离子通道及其电活动的生理和病理学研究成果。