Cholesterol metabolism: from lipidomics to immunology

Oxysterols, the oxidized forms of cholesterol or of its precursors, are formed in the first steps of cholesterol metabolism. Oxysterols have interested chemists, biologists, and physicians for many decades, but their exact biological relevance in vivo, other than as intermediates in bile acid biosynthesis, has long been debated. However, in the first quarter of this century, a role for side-chain oxysterols and their C-7 oxidized metabolites has been convincingly established in the immune system. 25-Hydroxycholesterol has been shown to be synthesized by macrophages in response to the activation of Toll-like receptors and to offer protection against microbial pathogens, whereas 7α,25-dihydroxycholesterol has been shown to act as a chemoattractant to lymphocytes expressing the G protein-coupled receptor Epstein-Barr virus-induced gene 2 and to be important in coordinating the action of B cells, T cells, and dendritic cells in secondary lymphoid tissue. There is a growing body of evidence that not only these two oxysterols but also many of their isomers are of importance to the proper function of the immune system. Here, we review recent findings related to the roles of oxysterols in immunology.     

Analysis of mtDNA sequences shows Japanese native chickens have multiple origins

In this study, we analysed the mitochondrial DNA D-loop region of Japanese native chickens to clarify their phylogenetic relationships, possible maternal origin and routes of introduction into Japan. Seven haplogroups (Types A-G) were identified. Types A-C were observed in Jidori, Shokoku and related breeds. However, Type C was absent in Shokoku, which was introduced from China, while most Indonesian native chickens were included in the Type C haplogroup. Types D-G were observed in Shamo and related breeds. Type E had a close genetic relationship with Chinese native chickens. Our results indicate that some breeds were not introduced into Japan as suggested in conventional literature, based on low nucleotide diversity of certain chicken breeds. Sequences originating from China and Korea could be clearly distinguished from those originating from Southeast Asia. In each group, domestic chickens were divided into the Jidori-Shokoku and Shamo groups. These results indicate that Chinese and Korean chickens were derived from Southeast Asia. Following the domestication of red junglefowl, a non-game type chicken was developed, and it spread to China. A game type chicken was developed in each area. Both non-game and game chickens formed the foundation of Japanese native chickens.     

酵母表面展示技术应用的最新进展

酵母表面展示(yeast surface display, YSD)技术是一种将外源靶蛋白基因序列与特定的载体基因序列融合后导入酵母细胞,利用酵母细胞内蛋白转运机制将靶蛋白表达并定位于酵母细胞表面的技术,最常用的是α-凝集素表达系统。酵母细胞具有真核细胞翻译后修饰机制,能够帮助目的蛋白正确折叠,可以用来展示各种真核蛋白,包括抗体、受体、酶和抗原肽等。酵母表面展示技术已成为生物技术和生物医学领域的强大蛋白质工程工具,结合流式细胞分选可用于改善蛋白质性质,包括亲和力、特异性、酶功能和稳定性等。本文从文库构建与筛选、抗体工程、蛋白质工程、酶工程和疫苗开发等方面对酵母表面展示技术应用最新进展进行了综述。     

细菌糖基化基本元件及其应用研究进展

近年来,细菌糖基化修饰系统的研究受到了越来越广泛的关注.已有文献报道了诸多细菌糖基化修饰系统,包括最具有代表性的空肠弯曲杆菌的N-糖基化修饰系统以及脑膜炎奈瑟菌的O-糖基修饰系统.本文在已有的研究基础上进行了系统的归纳总结,讨论对细菌蛋白质糖基化系统的理解,同时综述了细菌蛋白质糖基化应用方面的相关进展.     

植被含水量高光谱遥感监测研究进展

植被含水量是陆地植被重要的生物物理特征, 其定量遥感反演有助于植被干旱胁迫的实时监测与诊断评估。该文系统综述了国内外利用高光谱遥感评估植被水分状况的4个常见植被水分指标——冠层含水量、叶片等量水厚度、活体可燃物湿度和相对含水量的概念及其遥感估算方法研究进展, 评述了植被含水量高光谱遥感估算各类方法的优缺点, 探讨了植被含水量高光谱遥感估算目前存在的问题, 并提出进一步的研究任务, 即服务于植被干旱胁迫的高光谱遥感监测、预警与评估。     

乙肝基因疫苗在BALB/c小鼠体内的效力评价

采用ＨＢｓＡｇ高表达细胞株（ＣＨＯ－Ｃ２８）试制的乙肝基因疫苗,对ＢＡＬＢ／ｃ小鼠进行免疫,四周后进行了血清效力评价。并同时与血源乙肝疫苗进行了比较。结果表明,乙肝基因疫苗能达到与乙肝血源疫苗相同的免疫效果。     

Phylogeography and refugia of the Japanese endemic alpine plant, Phyllodoce nipponica Makino (Ericaceae)

Aim  This study aims to elucidate the phylogeography of the Japanese endemic alpine plant, Phyllodoce nipponica Makino (Ericaceae) and to infer the location of refugia of alpine plants in Japan during climatic oscillations.
Location  Alpine zone in the Japanese archipelago.
Methods  We determined the chloroplast (cp) DNA haplotypes of 155 individuals (22 populations) based on sequence data from the trnL-F and trnT-L intergenic spacers and the trnL intron, whose phylogenetic relationships were analysed using the program tcs . To examine the genetic structure, analysis of molecular variance ( amova ) was carried out and the population differentiation was shown by the parameters G _ST and N _ST.
Results  The haplotype composition and the results of amova showed that populations in the Japanese Central Mountain Region (JCMR) and in the westernmost region were highly divergent (18.8%). The diversity within populations was very high in the JCMR ( h _S = 0.421); less variation was found within populations located in other regions at lower elevations.
Main conclusions  Phyllodoce nipponica survived climatic changes during the Quaternary in the JCMR and the westernmost region. Most of the distribution range was colonized during only one range expansion. The source location from which the range expansion occurred was unclear.     

Short-Term Temporal Changes in Tree Live Biomass in a Central Amazonian Forest, Brazil

We monitored seventy-two 1 ha permanent plots spread over 64 km² of terra firme forest at Reserva Ducke (Manaus, Amazonas, Brazil) over 2-yr intervals to assess the effects of a soil and topographic gradient on the rate of change in the aboveground tree live biomass (AGLB). AGLB increased significantly over the 2-yr intervals, exhibiting a mean rate of change of 1.65 Mg/ha/yr (bootstrapped 95% CI: 1.15, 2.79). The rate of change varied according to tree size class; understory and sub-canopy trees exhibited higher rates of change. Over the whole period, the rate of change was not related to soil or topographic features of the plots, but there was evidence that the relationships varied depending on the year of measurement. In the plots monitored between 2001 and 2003 we found a significant relationship between AGLB change and the soil textural gradient, but this relationship was not evident in plots monitored between 2002 and 2004. This suggests that both the temporal variation in the soil–biomass change relationship and the size structure of the forest need to be included in models of biomass change in Amazonia. We also noted that the rate of biomass change is sensitive to the equation used to estimate AGLB. Allometric models that incorporate wood-density data provide higher per plot AGLB estimates, but lower rates of change, suggesting that variations in floristic composition have important implications for carbon cycling in diverse tropical forests.
Abstract in Portuguese is available at http://www.blackwell-synergy.com/loi/btp .     

结核分枝杆菌四价 DNA 疫苗免疫原性 和保护效率研究

对结核杆菌四价 DNA 疫苗的免疫应答和保护效果进行了评价. 用编码结核分枝杆菌 Ag85B、 MPT64、 MPT70 和 PstS-3 等 4 种抗原蛋白的基因分别构建的单价 DNA 疫苗混合成四价苗免疫小鼠. 3 次免疫后 21 天,四种抗原特异性抗体滴度分别达到 1∶6 400、 1∶51 200、 1∶6 400、 1∶ 6 400. 四种蛋白质均能诱导脾脏细胞产生较高水平的抗原特异性 IFN-γ,浓度分别为 10 582.14 ng/L、 13 635.97 ng/L、 14 213.15 ng/L 和 9 657.35 ng/L. 三次免疫后经静脉强毒攻击,四价苗组小鼠肺脏和脾脏的载菌数分别减少到阴性组的 1/650 和 1/130. 对肺组织的病理形态特征观察表明,空载体免疫的小鼠肺部严重损伤,肺实质干酪样坏死,坏死结节占肺实质的 70%~80%,而四价苗免疫的小鼠,肺组织结构正常,肺泡轮廓清晰. 研究首次证实, Ag85B、 MPT64、 MPT70 和 PstS-3 4 种结核杆菌抗原蛋白编码基因组成的四价 DNA 疫苗,具有很高的免疫应答水平和保护效率.     

DNA疫苗的黏膜免疫

DNA做为一种新型的疫苗在免疫人和动物后可以引起强烈的体液免疫和细胞免疫.目前大多数DNA疫苗都是通过肌肉注射和基因枪肠道外途径免疫.然而通过黏膜途径免疫机体也可以得到有效的保护.现主要就DNA疫苗的黏膜免疫进展作一综述.