光照强度对大花旋蒴苣苔叶形态和生理指标的影响

以复苏植物大花旋蒴苣苔(Boea clarkeana)为盆栽实验材料,通过梯度遮光处理,研究不同光照强度(100%、80%、60%、40%和20%透光率)和不同处理时间(30、60、90、120和150d)对大花旋蒴苣苔叶生长指标和生理指标的影响。结果表明:随着光照强度的减弱,大花旋蒴苣苔叶的各生长指标(叶片长、叶片宽、叶柄长、叶柄直径以及叶面积)呈现先增大后减小的趋势,透光率为60%时达到最大值;全光照(100%透光率)时,大花旋蒴苣苔表现出明显的外伤症状,透光率为80%和20%时,分别表现出中度伤害和轻度伤害,透光率为40%和60%时,未出现明显的外伤症状;过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和过氧化物酶(POD)3种抗氧化酶活性均较低且随着光强减弱呈现先降低后升高的趋势,随着处理时间的延长呈先上升后下降的趋势,全光照时抗氧化酶的活性最大,透光率60%处理下酶活性相对较低;丙二醛(MDA)含量、脯氨酸(Pro)含量和质膜透性随着光强减弱呈先降低后升高的趋势,随着处理时间的延长显著升高;叶绿素含量随着光强减弱呈逐渐上升的趋势,随着处理时间的延长先降低后升高。分析表明,40%～60%的透光率有利于大花旋蒴苣苔的生长,强光和弱光对大花旋蒴苣苔的生长均不利。     

Insulin-like growth factor 2 regulates the proliferation and differentiation of rat adipose-derived stromal cells via IGF-1R and IR

BackgroundInsulin-like growth factor 2 (IGF2), an essential component of the stem cell niche, has been reported to modulate the proliferation and differentiation of stem cells. Previously, a continuous expression of IGF2 in tissues was reported to maintain the self-renewal ability of several types of stem cells. Therefore, in this study, we investigated the expression of IGF2 in adipose tissues and explored the effects of IGF2 on adipose-derived stromal cells (ADSCs) in vitro.MethodsThe expression pattern of IGF2 in rat adipose tissues was determined by gene expression and protein analyses. The effect of IGF2 on proliferation, stemness-related marker expression and adipogenic and osteogenic differentiation was systematically investigated. Furthermore, antagonists of IGF2-specific receptors—namely, BMS-754807 and picropodophyllin—were added to explore the underlying signal transduction mechanisms.ResultsIGF2 levels displayed a tendency to decrease with age in rat adipose tissues. After the addition of IGF2, isolated ADSCs displayed higher proliferation and expression of the stemness-related markers NANOG, OCT4 and SOX2 and greater differentiation potential to adipocytes and osteoblasts. Additionally, both type 1 insulin-like growth factor receptor (IGF-1R) and insulin receptor (IR) participated in the IGF2-mediated promotion of stemness in ADSCs.ConclusionsOur findings indicate that IGF2 could enhance the stemness of rat ADSCs via IGF-1R and IR and may highlight an effective method for the expansion of ADSCs for clinical application.     

尿苷二磷酸糖固定化酶合成法研究

利用生物酶进行体外催化反应合成不同种类的尿苷二磷酸糖（uridine diphosphate sugar,UDP-糖）,生物酶的重复利用率较低。为提高尿苷二磷酸糖的合成效率及增加产物种类,以镍螯合聚丙烯酸酯树脂为载体,对带有HIS标签的N-乙酰己糖胺激酶（N-acetylhexosamine kinase,NahK）和尿苷转移酶（uridine transferase,GlmU）进行固定化。以固定化NahK和固定化GlmU为催化酶,不同单糖作为底物,研究尿苷二磷酸糖的一锅法合成情况。利用Q柱对产物进行纯化,通过高效液相色谱法、质谱法、核磁共振氢谱法对反应产物进行检测。确定了镍螯合聚丙烯酸酯树脂对游离NahK和GlmU的实际载量分别为10和20 mg·g^-1。固定化酶量的最优配比为5.5 g固定化NahK和2.5 g固定化GlmU。固定化酶的最适pH和温度分别为8.0和35℃,且能在重复反应中稳定反应5个批次。葡萄糖、N-乙酰氨基葡萄糖和甘露糖可以参与一锅法反应,生成UDP-糖的相对分子质量分别为566、607、566,而葡萄糖醛酸、半乳糖和果糖在该体系下不能合成相应的UDP-糖。基于固定化酶技术,一锅法可合成UDP-葡萄糖、UDP-N-乙酰氨基葡萄糖、UDP-甘露糖。     

Invalidation of Hyperamoeba by Transferring its Species to Other Genera of Myxogastria

ABSTRACT. The genus Hyperamoeba Alexeieff, 1923 was established to accommodate an aerobic amoeba exhibiting three life stages—amoeba, flagellate, and cyst. As more species/strains were isolated, it became increasingly evident from small subunit (SSU) gene phylogenies and ultrastructure that Hyperamoeba is polyphyletic and its species occupy different positions within the class Myxogastria. To pinpoint Hyperamoeba strains within other myxogastrid genera we aligned numerous myxogastrid sequences: whole small subunit ribosomal (SSU or 18S rRNA) gene for 50 dark‐spored (i.e. Stemonitida and Physarida) Myxogastria (including a new “Hyperamoeba”/Didymium sequence) and a ～400‐bp SSU fragment for 147 isolates assigned to 10 genera of the order Physarida. Phylogenetic analyses show unambiguously that the type species Hyperamoeba flagellata is a Physarum (Physarum flagellatum comb. nov.) as it nests among other Physarum species as robust sister to Physarum didermoides. Our trees also allow the following allocations: five Hyperamoeba strains to the genus Stemonitis; Hyperamoeba dachnaya, Pseudodidymium cryptomastigophorum, and three other Hyperamoeba strains to the genus Didymium; and two further Hyperamoeba strains to the family Physaridae. We therefore abandon the polyphyletic and redundant genus Hyperamoeba. We discuss the implications for the ecology and evolution of Myxogastria, whose amoeboflagellates are more widespread than previous inventories supposed, being now found in freshwater and even marine environments.     

用3E原则评价云南野生裸子植物遗传资源收集保存的优先性

为了探讨局部地区遗传资源优先性评价的方法和管理问题,我们采用"3E"原则对云南裸子植物进行了评价."3E"分别指珍稀濒危的(Endangered)、特有的(Endemic)和具有经济价值的(Economic)三个方面.我们首先介绍了"3E"原则的由来、内涵和价值,并应用"3E"原则,以种(变种)为分析单元,对分布于云南的10科29属107种(变种)野生裸子植物遗传资源的状况进行了分析,确定了需要优先保护的遗传资源类群.结果表明,云南省野生裸子植物资源兼有受威胁严重、特有率高、经济价值高等多种特征,如南方红豆杉(Taxus chinensis var.mairei)、灰干苏铁(Cycas hongheensis)、油麦吊云杉(Picea brachytyla var.complanata)等58种不仅受威胁严重,而且具有重要的经济价值和潜在的开发利用价值.具有"3E"特性的裸子植物遗传资源有72种,其中贡山三尖杉(Cephalotaxus lanceolata)、苏铁(Cycas revoluta)、大理罗汉松(Podocarpus forrestii)、德保苏铁(C.debaoensis)、德钦柏(Juniperus baimashanensis)、巧家五针松(Pinus squamata)、灰干苏铁、万钧柏(J.chengii)、毛枝五针松(P.wangii)等9种亟待进行抢救性保存,中甸冷杉(Abies ferreana)、绿春苏铁(C.tangingii)、麦吊杉(Picea brachytyla)、怒江冷杉(A.nukiangensis)、河内苏铁(C.tonkinensis)等40种需要优先收集和保存.保存的方式包括原地保存、异地保存、设施保存和栽培利用等综合措施.将"3E"原则应用于云南裸子植物遗传资源的管理,具有科学合理性和可操作性,对遗传资源的保护和可持续利用具有一定的参考价值.     

Biodiesel production using Aspergillus niger as a whole‐cell biocatalyst in a packed‐bed reactor

Enzymatic lipase transesterification of palm oil to biodiesel in a packed‐bed reactor (PBR) using a novel strain of the fungus Aspergillus niger, immobilized within polyurethane biomass support particles (BSPs), was investigated. A three‐step addition of methanol was used to reduce lipase inhibition by immiscible methanol. The influence of water content and PBR flow rate was investigated. FAME yield was enhanced with an increase of PBR flow rate in the range of 0.15–30 L h^?1, where inefficient mixing of the reaction mixture at lower flow rates resulted in low conversion rates i.e. 69% after 72‐h reaction. Adding the third mole equivalent of methanol resulted in lipase inhibition due to methanol migration into the accumulated glycerol layer. Glutaraldehyde (GA) solution (0.5 vol.%) was used to stabilize lipase activity, which led to a high FAME yield (>90%) in the PBR after 72‐h of reaction time at a flow rate of 15 L h^?1, and a water content of 15%. Moreover, a high conversion rate (>85%) was maintained after four palm oil batch conversion cycles in the PBR. In contrast, lipase activity of non‐GA‐treated cells decreased with each PBR batch cycle, where only 70% FAME was produced after the forth PBR cycle. Transesterification of palm oil in a PBR system using BSPs‐immobilized A. niger as a whole‐cell biocatalyst is a viable process for enzymatic biodiesel production.     

黄河裸裂尻鱼肥胖基因克隆及其对青藏高原季节性冷环境的适应性表达

目的克隆黄河裸裂尻鱼肥胖基因(obese gene,ob),分析编码蛋白leptin的序列特征,检测ob mR-NA的组织特异性表达和不同环境温度下肝胰脏和白肌ob mRNA的相对表达水平,为探究黄河裸裂尻鱼在青藏高原季节性寒冷环境下的生态适应机制提供科学数据。方法利用RT-PCT、5’-RACE和3’-RACE法获得ob基因全长cDNA序列。通过已知cDNA序列设计半定量RT-PCR和real-time PCR引物,进行表达研究。结果黄河裸裂尻鱼ob基因序列全长为1 337 bp,其中开放阅读框(ORF)长513 bp,编码170个氨基酸。黄河裸裂尻鱼ob mRNA在心脏、肾脏、脂肪、肠、精巢、肝胰脏、鳃、脑和肌肉9个被检组织中均有表达,其中在心脏中表达最强,肌肉组织中表达最弱。栖息水域环境温度下降,将显著抑制黄河裸裂尻鱼肝胰脏和白肌ob mRNA的表达。结论黄河裸裂尻鱼ob基因特殊的组织表达特征可能与其特定组织的能量代谢及其特殊的生物学功能有关。Leptin在黄河裸裂尻鱼能量代谢调节和季节性环境适应方面发挥着重要作用。     

SARS冠状病毒结构蛋白在血清学诊断中潜在应用价值的比较

为了确定特异的SARS抗体检测抗原,比较了SARS冠状病毒(SARS-CoV)主要结构蛋白与SARS患者血清的反应性。从SARS死亡患者的肺组织提取的总RNA为模板,用RT-PCR技术分别扩增S、N、M和E4种结构蛋白基因,对3种S截短突变体和N、M、E的重组蛋白在大肠杆菌中进行表达。以表达的蛋白为抗原,应用Western blot跟踪检测11例SARS患者血清54份。结果显示：SARS—CoV的重组N蛋白和s蛋白有很强的抗原性,s蛋白的3个区段的抗原性强弱存在差异,S3抗原性强于S1和s2;在患病第1周、2周、3周及3周以上,N蛋白和s3蛋白抗体检出率分别为40％、65。2％、100％、100％和40％、61％、76.2％、100％;提示SARS-CoV重组N蛋白和S3蛋白在SARS的血清学诊断中有一定的应用价值。