Later Passages of Neural Progenitor Cells from Neonatal Brain Are More Permissive for Human Cytomegalovirus Infection

Congenital human cytomegalovirus (HCMV) infection is the most frequent infectious cause of birth defects, primarily neurological disorders. Neural progenitor/stem cells (NPCs) are the major cell type in the subventricular zone and are susceptible to HCMV infection. In culture, the differentiation status of NPCs may change with passage, which in turn may alter susceptibility to virus infection. Previously, only early-passage (i.e., prior to passage 9) NPCs were studied and shown to be permissive to HCMV infection. In this study, NPC cultures derived at different gestational ages were evaluated after short (passages 3 to 6) and extended (passages 11 to 20) in vitro passages for biological and virological parameters (i.e., cell morphology, expression of NPC markers and HCMV receptors, viral entry efficiency, viral gene expression, virus-induced cytopathic effect, and release of infectious progeny). These parameters were not significantly influenced by the gestational age of the source tissues. However, extended-passage cultures showed evidence of initiation of differentiation, increased viral entry, and more efficient production of infectious progeny. These results confirm that NPCs are fully permissive for HCMV infection and that extended-passage NPCs initiate differentiation and are more permissive for HCMV infection. Later-passage NPCs being differentiated and more permissive for HCMV infection suggest that HCMV infection in fetal brain may cause more neural cell loss and give rise to severe neurological disabilities with advancing brain development.     

病毒颗粒:药物靶向传递领域中的新型载体

由于具有高效靶向药物传递的潜力,病毒颗粒已成为药物和生命科学领域的研究焦点.病毒颗粒具有病毒性载体和非病毒性载体的优点,同时克服了两者的局限性.病毒颗粒药物传递系统具有无毒、生物相容性、生物可降解性和非自动免疫等特点.研究表明,病毒颗粒能够在细胞间转运多种具有生物活性的分子,例如核酸或者基因、多肽、蛋白质以及其它抗癌药物等,因此在疾病治疗方面可能具有重要作用.如何制备携带有生物活性材料和治疗试剂的病毒颗粒和确定病毒颗粒药物的最佳剂型是目前该领域中挑战性的课题.本文综述了病毒颗粒技术多方面的特征及应用前景.     

Reactive oxygen species (ROS) generated by cyanobacteria act as an electron acceptor in the biocathode of a bio-electrochemical system

The enhanced electricity generation in a biocathode bio-electrochemical system (BES) with Microcystis aeruginosa IPP as the cathodic microorganism under illumination is investigated. The results show that this cyanobacterium is able to act as a potential cathodic microorganism under illumination. In addition, M. aeruginosa IPP is found to produce reactive oxygen species (ROS) in its growth in the BES. ROS, as more competitive electron acceptors than oxygen, are utilized prior to oxygen. The BES current is substantially reduced when the ROS production is inhibited by mannitol, indicating that the ROS secreted by the cyanobacterium play an important role in the electricity generation of such a biocathode BES. This work demonstrates that the ROS released by cyanobacteria benefit for an enhanced electricity generation of BES.     

细胞外ATP和水杨酸对烟草光合指标的影响

研究了细胞外ATP(eATP)和水杨酸(SA)对烟草(Nicotiana tabacum)叶片的气孔导度(GH2 O)、蒸腾速率(E)、光合作用速率(A)与叶绿素荧光参数[包括PSⅡ潜在最大光化学量子效率(Fv/Fm)、PSⅡ光适应下实际光化学效率Y(Ⅱ)、电子传递速率(ETR)、非光化学荧光淬灭(NPQ)和光化学荧光淬灭(qP)]的影响。结果表明：SA能导致A、GH2 O和E的下降,而eATP的处理能缓解SA造成的A、GH2 O和E的下降;但SA未对叶绿素荧光参数Fv/Fm、Y(Ⅱ)、NPQ、qP和ETR造成显著影响,eATP的加入也未改变SA处理下叶片叶绿素荧光参数的水平。这说明SA能导致光合作用的抑制,而eATP能明显缓解SA对光合作用的抑制,但以上作用可能均和光反应阶段无关。并对其内在机理进行了探讨。     

Distinct mechanisms for cross-protection of the upper versus lower respiratory tract through intestinal priming

A main feature of the common mucosal immune system is that lymphocytes primed in one mucosal inductive site may home to distant mucosal effector sites. However, the mechanisms responsible for such cross-protection remain elusive. To address these we have used a model of local mucosal infection of mice with reovirus. In immunocompetent mice local duodenal priming protected against subsequent respiratory challenge. In the upper respiratory tract this protection appeared to be mainly mediated by specific IgA- and IgG2a-producing B cells, whereas ex vivo active effector memory CTL were found in the lower respiratory tract. In accordance with these findings, clearance of reovirus from the lower respiratory tract, but not from the upper respiratory tract, of infected SCID mice upon transfer of gut-primed lymphocytes depended on the presence of T cells. Taken together this study reveals that intestinal priming leads to protection of both the upper and lower respiratory tracts, however through distinct mechanisms. We suggest that cross-protection in the common mucosal immune system is mediated by trafficking of B cells and effector memory CTL.     

Substrate consumption and excess sludge reduction of activated sludge in the presence of uncouplers: a modeling approach

A mathematical model with a consideration of energy spilling is developed to describe the activated sludge in the presence of different levels of metabolic uncouplers. The consumption of substrate and oxygen via energy spilling process is modeled with a Monod term, which is dependent on substrate and inhibitor. The sensitivity of the developed model is analyzed. Three parameters, maximum specific growth rate (μ _max), energy spilling coefficient (q _max), and sludge yield coefficient (Y _H) are estimated with experimental data of different studies. The values of μ _max, q _max, and Y _H are found to be 6.72 day^-1, 5.52 day^-1, and 0.60 mg COD mg^-1 COD for 2, 4-dinitrophenol and 7.20 day^-1, 1.58 day^-1, and 0.62 mg COD mg^-1 COD for 2, 4-dichlorophenol. Substrate degradation and sludge yield could be predicted with this model. The activated sludge process in the presence of uncouplers that is described more reasonably by the new model with a consideration of energy spilling. The effects of uncouplers on substrate consumption inhibition and excess sludge reduction in activated sludge are quantified with this model.     

重组谷糠源过氧化物酶的克隆、表达及逆转结肠癌化疗耐药活性

本课题组前期首次从谷糠中获得具抗肿瘤活性的过氧化物酶FMBP。为了该蛋白质后期在体外的规模化生产,本研究以谷子cDNA为模板,利用基因工程手段构建了pMal-s-FMBP融合质粒,并优化诱导条件进行原核表达与纯化,最终获得纯度大于90 %的具抗肿瘤活性的重组FMBP（Re-FMBP）。研究发现,Re-FMBP可以逆转HCT-8/5-Fu耐药细胞对5-Fu的耐药性,耐药逆转倍数达到9.6倍。通过Annexin V/碘化丙啶双染色流式细胞仪检测显示：Re-FMBP能够诱导HCT-8/5-Fu耐药细胞发生凋亡;通过罗丹明123染色,流式细胞仪检测结果显示,Re-FMBP处理后,HCT-8/5-Fu耐药细胞内的荧光强度增强。说明Re-FMBP能够增加5-Fu药物在HCT-8/5-Fu耐药细胞内的蓄积。结果揭示,Re-FMBP蛋白可通过抑制耐药细胞增殖,诱导耐药细胞凋亡,抑制耐药细胞对5-Fu药物外排功能来增加HCT-8/5-Fu耐药细胞对5-Fu药物的敏感性。因此,谷糠来源的Re-FMBP蛋白可以作为肿瘤化疗辅助药物来开发。     

Electricity generation from mixed volatile fatty acids using microbial fuel cells

Fermentative hydrogen production, as a process for clean energy recovery from organic wastewater, is limited by its low hydrogen yield due to incomplete conversion of substrates, with most of the fermentation products being volatile fatty acids (VFAs). Thus, further recovery of the energy from VFAs is expected. In this work, microbial fuel cell (MFC) was applied to recover energy in the form of electricity from mixed VFAs of acetate, propionate, and butyrate. Response surface methodology was adopted to investigate the relative contribution and possible interactions of the three components of VFAs. A stable electricity generation was demonstrated in MFCs after the enrichment of electrochemically active bacteria. Analysis showed that power density was more sensitive to the composition of mixed VFAs than coulombic efficiency. The electricity generation could mainly be attributed to the portion of acetate and propionate. However, the two components showed an antagonistic effect when propionate exceeded 19%, causing a decrease in coulombic efficiency. Butyrate was found to exert a negative impact on both power density and coulombic efficiency. Denaturing gradient gel electrophoresis profiles revealed the enrichment of electrochemically active bacteria from the inoculum sludge. Proteobacteria (Beta-, Delta-) and Bacteroidetes were predominant in all VFA-fed MFCs. Shifts in bacterial community structures were observed when different compositions of VFA mixtures were used as the electron donor. The overall electron recovery efficiency may be increased from 15.7% to 27.4% if fermentative hydrogen production and MFC processes are integrated.     

Impact of a static magnetic field on the electricity production of Shewanella-inoculated microbial fuel cells

The electricity production of Shewanella-inoculated microbial fuel cells (MFCs) under magnetic field (MF) exposure was investigated in different reactor systems. The persistency of the MF effect and the influences of MF intensity and direction on MFC performance were also studied. Application of a 100-mT static MF to the MFCs improved electricity production considerably, with an increase in the maximum voltage by 20-27% in both single- and two-chamber MFCs, while a more conspicuous improvement in the electricity generation was observed in a three-electrode cell. The MF effects were found to be immediate and reversible, and adverse effects seemed to occur when the MF was suddenly removed. The medium components analysis demonstrated that the application of MF led to an enhanced bioelectrochemical activity of Shewanella, and no significant promotion in mediator secretion was found. The improvement in the electricity production of MFCs under MF was mainly attributed to the enhanced bioelectrochemical activity, possibly through the oxidative stress mechanism. An accelerated cell growth under MF might also contribute to the enhanced substrate degradation and power generation.