Free N-linked oligosaccharide chains: Formation and degradation

There is growing evidence that N-linked glycans play pivotal roles in protein folding and intra- and/or intercellular trafficking of N-glycosylated proteins. It has been shown that during the N-glycosylation of proteins, significant amounts of free oligosaccharides (free OSs) are generated in the lumen of the endoplasmic reticulum (ER) by a mechanism which remains to be clarified. Free OSs are also formed in the cytosol by enzymatic deglycosylation of misfolded glycoproteins, which are subjected to destruction by a cellular system called “ER-associated degradation (ERAD).” While the precise functions of free OSs remain obscure, biochemical studies have revealed that a novel cellular process enables them to be catabolized in a specialized manner, that involves pumping free OSs in the lumen of the ER into the cytosol where further processing occurs. This process is followed by entry into the lysosomes. In this review we summarize current knowledge about the formation, processing and degradation of free OSs in eukaryotes and also discuss the potential biological significance of this pathway. Other evidence for the occurrence of free OSs in various cellular processes is also presented.     

基于专利分析的生物传感器发展态势研究*

生物传感器将固定化的生物敏感材料作为识别元件,具有体积小、专一性强、响应快、准确度高等特点,市场应用前景广阔。近年来,生物传感器技术发展迅速,研究成果不断涌现。为更好地了解我国生物传感器研究现状,进一步促进生物传感器行业健康快速发展,基于IncoPat专利数据库,利用ITGinsight作为文献分析工具,对全球范围内生物传感器领域的总体研究态势、区域布局、技术构成及研究热点等方面进行专利分析,并对核心专利进行识别。结果表明,我国生物传感器领域的专利数量排在世界前列,但科研实力存在区域分布不均衡、企业研发实力不强、关键核心技术不足等问题。针对这些问题,提出我国生物传感器技术的未来发展策略。     

发酵透明质酸寡糖兽疫链球菌工程菌株的构建

透明质酸(HA)广泛应用于医学、化妆品、食品等领域。HA的生物活性取决于其分子量(M_w)。透明质酸寡糖由于具有重要的生理活性与特殊生理功能,在医药领域具有重要的应用前景。兽疫链球菌因其发酵周期短、生产强度较强的特点,在商业生产HA上具有广泛的应用。为了高效发酵合成透明质酸寡糖和解决发酵过程的溶氧问题,文中通过在兽疫链球菌WSH-24中过表达透明质酸合酶HasA以及优化表达水蛭来源的透明质酸酶LHAase。重组菌株摇瓶发酵24h,透明质酸寡糖积累至0.97g/L,比野生菌提高了182.0%。在3L发酵罐中发酵24 h,透明质酸寡糖生产强度为294.2 mg/(L·h),HA积累至7.06 g/L,比野生菌的罐上水平提高了112.4%。文中所构建的发酵合成透明质酸寡糖的兽疫链球菌重组菌株具有重要的应用前景。     

丝绸之路经济带核心区新疆城镇建设用地扩展的时空演变特征及影响机理

将丝绸之路经济带核心区新疆城镇建设用地扩展作为一个时空变化系统进行分析,提取1980—2015年7个年份用地演变信息,结合10 km×10 km方格网构建,从总量趋势、分地州市级区域、分用地类型及特殊性全面认知扩展的时空演变特征,采用地理探测器模型,在县域尺度定量诊断城镇建设用地扩展的人文要素和自然要素的影响程度及各要素间的交互影响作用,进而识别其主控要素并探讨其作用机理,对比分析天山北坡城市群和喀什都市圈两个重点发展区域的分异性。研究结果表明:近35年以来,丝绸之路经济带核心区新疆城镇建设用地扩展约2.9倍,扩展强度波动增长且以分散小斑块为主,各地州市扩展规模和强度的时空差异性显著,次一级城镇建设用地类型扩展呈现动态变化特征,用地扩展受自然本底胁迫条件和经济社会发展过程多重影响有其特殊性;全域城镇建设用地在县域尺度以低水平扩展与各级人文要素和自然要素水平的耦合匹配关系为主;综合地理探测器因子分析模块和交互作用模块的探测结果,判定地形位指数、城镇化率、地形起伏度、二三产业比重为影响丝绸之路经济带核心区新疆县域城镇建设用地扩展的主控要素,并探寻各主控要素的作用机理;在重点发展区域天山北坡城市群和喀什都市圈的驱动要素有共性也有明显分异性。该研究为丝绸之路经济带核心区新疆城镇建设用地因地因城因类的差别化调控及区域可持续发展提供科学支撑和决策依据。     

Nature reserve group planning for conservation of giant pandas in North Minshan, China

Formation of nature reserve groups (NRGs) is an important approach for optimising spatial patterns in nature reserves and for improving the efficiency of nature reserve networks. In this study, based on habitat evaluation and connectivity analysis, the approach and method for optimising spatial patterns and functional zoning of reserves were analysed using the case study of giant panda (Ailuropoda melanoleuca) reserves in North Minshan. Results indicated that five panda nature reserves had been established, which formed a reserve group and covered 48.4% of panda habitat and three of five population components. Although the nature reserves were connected to each other, core zones were divided into seven isolated areas. These divisions can reduce the efficiency of protecting giant pandas in reserve systems. To optimise spatial patterns in nature reserves, one new reserve is proposed and it is recommended that core zones be expanded and merged into two areas, in accordance with the spatial distribution of the panda population. Three linkage areas are also proposed—for facilitating panda exchange and movement among different populations. The study is expected to provide a scientific basis for planning the development of nature reserves in this mountain range, to promote the establishment of nature reserve groups in other areas, and to optimise entire nature reserve systems in China.     

橄榄ISSR和RAPD遗传多样性分析和核心种质构建

为揭示中国橄榄(Canarium album)种质资源的遗传多样性,采用ISSR和RAPD标记对橄榄主要分布区的86份种质资源进行遗传多样性分析并构建核心种质。结果表明,基于UPGMA遗传相似系数,86份种质资源可分为3个大类;基于STRUCTURE模型聚类,可分为4个类群,这基本符合橄榄的地域性分布规律。采用ISSR和RAPD获得的中国橄榄种质资源的整体遗传多样性水平分别为0.284±0.169和0.244±0.163,多态性位点百分率分别为92.56%和100%,总遗传分化系数分别为0.127和0.142,基因流分别为3.423和3.025,群体间遗传相似系数分别为0.930和0.939,个体间遗传相似系数分别为0.736和0.732。因此,中国橄榄种质资源丰富的遗传多样性主要来源于个体间的遗传分化或变异,且这种遗传多样性存在明显的地域性差异。     

Species-Specific Association of the Cell-Aggregation Molecule Mediates Recognition in Marine Sponges

Reaggrcgation of dissociated cells of marine sponges, resulting in reformation of functional sponges, is a calcium-dependent process mediated by large, proteoglycan-like molecules termed aggregation factors (AF). During aggregation, species-specific sorting of cells is often observed. We purified and characterized AFs from three different sponge species and investigated their role in species-specific aggregation using novel approaches. The calcium-dependent association between purified AFs is species-specific in most combinations, as was shown in overlay assays and bead-sorting assays with AFs immobilized onto colored beads. Species-specific interactions of living cells and AF-beads resulted in incorporation of only homospecific AF-beads into reforming cell aggregates. Sequences from peptides obtained from the AF core proteins could all be aligned to the sequence of one species, the Microciona prolifera AFp3 core protein. In contrast to this similarity, major species-specific differences were seen in carbohydrate composition and in the response of AFs to specific carbohydrate-recognizing antibodies. In summary, our data point to a prominent role for the calcium-dependent association of AFs in recognition processes during aggregation. As this association of AFs occurs via carbohydrate -carbohydrate interactions, we speculate that the specificity of those interactions may be fundamental to recognition mechanisms required for regeneration of individuals from dissociated cells and for rejection of foreign material by sponge individuals.     

The Variability in Circadian Phase and Amplitude Estimates Derived from Sequential Constant Routines

Both the constant routine (CR) and the dim light melatonin onset have been suggested as reliable methods to determine circadian phase from a single circadian cycle. However, both techniques lack published studies quantifying the intercycle variability in their phase resolution. To address this question eight healthy male subjects participated in two CRs, 7 days apart. Circadian phase was determined using 3-min samples of core body temperature and two hourly urinary sulphatoxy melatonin excretion rates. Phase and amplitude were estimated using simple (24 h) and complex (24 + 12 h) cosinor models of temperature data and the onset, offset, and a distance-weighted-least-squares (DWLS) fitted acrophase for the melatonin metabolite. The variability in phase estimates was measured using the mean absolute difference between successive CRs. Using the simple 24 h model of temperature data, the mean absolute phase difference was 51 min (SD = 35 min). Using the complex model, the mean absolute phase difference was 62 min (SD = 35 min). Using the DWLS fitted acrophase for the melatonin metabolite, the mean absolute phase difference between CR1 and CR2 was 40 min (SD = 26 min). The results indicate that for CRs a week apart, the mean absolute difference in an individual's phase estimate can vary by 40-60 min depending on the choice of dependent measure and analytic technique. In contrast to the intraindi-vidual variability, the group results showed considerably less variability. The mean algebraic difference between CRs, using temperature- or melatonin-derived estimates, was less than 5 min, and well within the range of normal measurement error.     

Bright Light Therapy for Winter Depression—Is Phase Advancing Beneficial?

Bright light is the recommended treatment for winter seasonal affective disorder (SAD). Previously we showed that the antidepressant effect of morning (but not evening) light was greater than placebo after 3 weeks of treatment. Here, we determined if the magnitude and direction of circadian rhythm phase shifts produced by the bright light in the previous study were related to the antidepressant effects. Twenty-six SAD patients from the original sample of 96 had their rectal temperature continuously monitored while they participated in a placebo-controlled parallel design conducted over six winters. After a baseline week, there were three treatments for 4 weeks—morning light, evening light, or morning placebo. Bright light was produced by light boxes (?6000 lux). Placebos were sham negative ion generators. All treatments were 1.5 h in duration. Depression ratings were made weekly by blind raters. Circadian phase shifts were determined from changes in the timing of the core body temperature minimum (Tmin). Morning light advanced and evening light delayed the Tmin by about 1 h. The placebo treatment did not alter circadian phase. As the sleep schedule was held constant, morning light increased and evening light decreased the Tmin to wake interval, or phase angle between circadian rhythms and sleep. Phase advance shifts and increases in the phase angle were only weakly associated with antidepressant response. However, there was an inverted U-shaped function showing that regardless of treatment assignment the greatest antidepressant effects occurred when the phase angle was about 3 h, and that patients who moved closer to this phase angle benefited more than those who moved farther from it. However 46% of our sample had a phase angle within 30 min of this 3 h interval at baseline. So it does not appear that an abnormal phase angle can entirely account for the etiology of SAD. A majority (75%) of the responders by strict joint criteria had a phase angle within this range after treatment, so it appears that obtaining the ideal phase relationship may account for some, but not all of the antidepressant response. In any case, regardless of the mechanism for the antidepressant effect of morning light, it can be enhanced when patients sleep at the ideal circadian phase and reduced when they sleep at a more abnormal circadian phase.     

Glycogen Phosphorylase Activity in Fat Body During Development of the Silkworm,Bombyx mori

Changes in the small intestinal mucin contents in rats were evaluated by two methods, viz., a newly established ELISA and a method based on the measurement of O-linked oligosaccharide chains (OSC) as a mucin marker. Significant correlation was observed between the values of ELISA-derived mucins and OSC. The results confirm the usefulness of measurement of OSC as an alternative method for mucin determination.