中药山豆根的研究进展

本文对中药山豆根进行了本草考证,并概括总结了半个世纪以来国内外对山豆根(广豆根)和北豆根在生药学研究、化学成分、药理作用与临床应用等方面的研究成果,为山豆根的进一步研究提供参考。全文附参考文献105篇。     

Passive protective effect of egg-yolk antibodies against enterotoxigenic Escherichia coli K88+ infection in neonatal and early-weaned piglets

The protective effects of egg-yolk antibodies obtained from hens immunized with fimbrial antigens from a local strain (Escherichia coli K88+ MB, Manitoba, Canada) of K88+ piliated enterotoxigenic E. coli (ETEC) were evaluated in 3- and 21-day-old piglets in which ETEC diarrhea was induced and also in early-weaned piglets in a commercial farm. The results demonstrated that the E. coli K88+ MB-induced diarrhea in 3-day-old piglets was cured 24 h after treating with egg-yolk antibodies while those treated with egg-yolk powder from conventional hens continued to have diarrhea and 62.5% of them died of severe diarrhea. For 21-day-old weaned piglets, those fed egg-yolk antibodies had transient diarrhea, positive body weight gains and 100% survival during the period of the experiment, whereas control piglets that were treated with placebo had severe diarrhea and dehydration and some died within 48 h after infection. In the field trial, the incidence and severity of diarrhea of 14-18-day-old weaned piglets fed egg-yolk antibodies were much lower than in those fed a commercial diet containing an antibiotic. These results indicate that the neonatal and early-weaned piglets that received the egg-yolk antibodies were protected against ETEC infection.     

Lipidomic changes during different growth stages of Nitzschia closterium f. minutissima

Ultra Performance Liquid Chromatography-Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry (UPLC-ESI-Q-TOF–MS) is a powerful lipidomic tool. In this study, we developed a UPLC/Q-TOF–MS based method to investigate the lipid metabolomic changes in different growth phases of Nitzschia closterium f. minutissima. The data classification and biomarker selection were carried out by using multivariate statistical analysis, including principal components analysis (PCA), projection to latent structures with discriminant analysis (PLS-DA), and orthogonal projection to latent structures with discriminant analysis (OPLS-DA). We discovered that the intercellular lipid metabolites were significantly different among exponential, early stationary and late stationary phases. Thirty-one lipid molecules were selected and identified as putative biomarkers, including free fatty acid, Harderoporphyrin, phosphatidylglycerol, 1,2-diacyglycerl-3-O-4′-(N,N-trimethy)-homoserine, triacylglycerol, cholesterol, sulfoquinovosyldiacylglycerol, lyso-sulfoquinovosyldiacylglycerol, monogalactosyldiacylglycerol, digalactosyldiacylglycerol and lyso-digalactosyldiacylglycerol. These lipids have been shown previously to function in energy storage, membrane stability and photosynthesis efficiency during the growth of diatoms. Further analysis on the putative biomarkers demonstrated that nitrate starvation played critical role in the transition from exponential phase to stationary phase in N. closterium. This study is the first one to explore the lipidomic changes of microalgae in different growth phases, which promotes better understanding of their physiology and ecology.     

无花果叶共生菌发酵的菌种富集及抑菌活性的筛选

目的从无花果叶中分离和筛选能发酵分解无花果叶及具有抑菌作用的共生菌。方法采用以无花果叶作为唯一碳源的富集培养方法,分离共生菌并分析发酵菌群的构成。同时,通过研磨法直接分离无花果叶内生菌,对分离菌株进行分子生物学鉴定,利用平板滤纸片法进行菌株的抑菌活性分析。结果无花果叶发酵菌群由11种22株细菌构成,其中优势菌为短波单胞菌(Brevundimonas naejangsanensis)、嗜温鞘氨醇杆菌(Sphingobacterium thalpophilum)和副球菌(Paracoccus sp.)。没有获得发酵无花果叶的真菌菌群,只分离出1株产黄青霉菌(Penicillium chrysogenum)。直接分离共获得无花果叶内生细菌8种14株和内生真菌3种9株。抑菌试验表明,来源于富集培养的泡囊短波单胞菌(Brevundimonas vesicularis)和产黄青霉菌以及来源于内生菌的枯草芽胞杆菌(Bacillus subtilis)对枯草芽胞杆菌、大肠埃希菌和金黄色葡萄球菌3种指示菌有不同的抑菌作用,且它们的抑菌谱各不相同。泡囊短波单胞菌只在无花果叶中培养时才表现出抑菌活性。结论短波单胞菌可能与无花果叶的发酵分解有关,泡囊短波单胞菌与无花果叶之间发生了相互作用,因此,这2株菌可以作为无花果叶发酵的候选菌种应用。     

水稻OsMS2基因在花药发育中的功能分析

拟南芥MS2(MALE STERILITY 2)是一个调控花药花粉发育的关键基因。水稻OsMS2(Os03g07140)基因与拟南芥MS2的序列具有高度同源性。利用RNA干扰技术研究OsMS2基因在水稻花药发育过程中的功能。与野生型水稻相比, 转基因 植株营养生长阶段正常, 但雄性育性降低。转基因植株雄性育性降低与RNA干扰引起的OsMS2基因表达水平降低有关。进一步对转基因植株花药进行细胞学观察, 结果表明OsMS2基因表达水平的降低导致绒毡层细胞退化延迟, 小孢子壁的形成出现异常。扫描电镜观察结果显示, 小孢子壁光滑, 不能形成正常的外壁。以上结果表明OsMS2基因在水稻花药发育过程中起重要作用。     

Down－regulated expression of atypical PKC－binding domain deleted asip isoforms in human hepatocellular carcinomas

INTRODUCTIONCell polarity is the reflection of complex mechanisms that establish and maintain the functionally specialized regions in the plasma membrane and cytoplasm, and is fundamentally important for differentiation, proliferation, morphogenesis and other functions of simple and complicated organisms[1].Molecular mechanisms of cell polarity during animal development have been analyzed mainly in the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster[2]. In early …     

水杉人工林树冠结构及生物生产力的研究

研究了水杉人工林的树冠结构和林分生物生产力。结果表明,不同密度及林龄的林分树冠结构存在较大差异,随着树冠部位上升和林分密度增大,分枝角度逐渐减小;径阶大小与枝叶率成反比,与树冠重量成正比,径阶增大,树冠最大叶量层的集团上移,有效光合面积相对减少,树冠结构的变化直接影响到林分的生物量生产、分配分配和经济生物量,林分干、枝、叶的干物质累积趋势可用Ｒｉｃｈａｒｄ方程描述;林龄增大,分配到主干的生物量比例     

温度胁迫下棉花粉蚧热激蛋白基因的表达分析

【目的】为了研究热激蛋白 Hsp70, Hsp70-4和Hsp90在棉花粉蚧Phenacoccus solenopsis抵抗逆温中的作用。【方法】在测序棉花粉蚧转录组的基础上,分析了该虫热激蛋白Hsp70基因家族的2个序列［Pshsp70（GenBank登录号为KJ909505）和Pshsp70-4（GenBank登录号为KJ909506）］和Hsp90基因家族的1个序列,［Pshsp90(GenBank登录号为KJ909507)］,采用实时荧光定量 PCR（RT-qPCR）检测了在不同温度（18和32℃恒温, 37, 39, 41, 43和45℃热激1 h 后26℃恢复1 h)下棉花粉蚧不同发育阶段（2龄若虫、3龄若虫、雌成虫）3种热激蛋白基因的表达量。【结果】Pshsp70 cDNA序列包含1 923 bp的开放阅读框,编码641个氨基酸,理论分子量和等电点分别为70.9 kDa和5.65; Pshsp70-4 cDNA序列包含1 962 bp的开放阅读框,编码654个氨基酸,理论分子量和等电点分别为71.8 kDa和5.38;Pshsp90 cDNA序列包含2 172 bp的开放阅读框,编码724个氨基酸,理论分子量和等电点分别为83.5 kDa和4.93。Pshsp70 和Pshsp70-4均含有Hsp70基因家族高度保守的基序,Pshsp70编码的氨基酸序列与烟粉虱Bemisia tabaci和家蚕Bombyx mori等昆虫的Hsp70 的氨基酸序列一致性为 85%;Pshsp70-4编码的氨基酸序列与白蜡蚧Ericerus pela和点蜂缘蝽Riptortus pedestris等昆虫的Hsp70的氨基酸序列一致性高达95%;Pshsp90也含有Hsp90基因家族高度保守的基序,Pshsp90编码的氨基酸序列与赤拟谷盗Tribolium castaneum和东亚小花蝽Orius sauteri等昆虫的Hsp90 的氨基酸序列一致性为 87%。热激蛋白基因表达量分析结果表明,在18℃恒温条件下,粉蚧2龄若虫的3个PsHsps基因的mRNA相对表达量均比对照(26℃)低,在32℃恒温条件下,各龄期的Hsp70基因的相对表达量均显著高于对照。在37~45℃下热激1 h并在26℃下恢复1 h,棉花粉蚧3个龄期的3个热激蛋白PsHsps基因的相对表达量随温度的升高总体呈增加趋势,相关性分析表明,除Pshsp70-4在雌成虫中的表达量与热胁迫温度的相关系数为0.225外,各龄期中3个基因的表达量与温度的相关系数均大于0.6,显著相关;43℃和45℃胁迫下,各龄期的3个热激蛋白基因相对表达量均显著高于对照组（P<0.05）。【结论】棉花粉蚧热激蛋白基因的表达与温度呈正相关,在该虫应对高温中起着重要作用。     

Binding and Uptake of RGD-Containing Ligands to Cellular α v β 3 Integrins

The cyclic peptide, cRGDf[N(me)]V, binds to the α _v β ₃ integrin and can disrupt binding of the integrin to its natural ligands in the extracellular matrix. In this work, the ability of a water-soluble, fluorescently labeled variant of the RGD-containing peptide (cRGDfK-488) to bind to integrins on human umbilical vascular endothelial cells (HUVEC) and subsequently undergo endocytosis was characterized. This information was compared to the binding and uptake properties of an α _v β ₃ integrin-specific monoclonal antibody, LM609X. The specificity of the RGD-containing peptide is assessed by comparison with control peptide that does not bind to the α _v β ₃ integrin, cRADfK-488. Using a high purity construct, it is shown that the RGD ligand exhibits dissociation constants in the micromolar range whereas LM609X exhibits dissociation constants in the nanomolar range. However, the RGD ligand showed greater uptake following incubation at temperatures which permit endocytosis. A 7.4-fold increase in uptake of the RGD peptide was observed following a 1 h incubation with HUVEC at 37°C (an endocytosis permissive temperature), as compared to that at 4°C (an endocytosis prohibitive temperature). In contrast, only a 1.9-fold increase in cell-associated fluorescence was observed for similar incubations with LM609X. Results from fluorescence microscopy supports the notion that the RGD peptide is rapidly endocytosed at 37°C as compared to LM609X. These results are discussed with regard to previous work indicating that RGD ligands enter cells by integrin-independent pathways. These studies provide well-controlled measures of how RGD ligands stimulate endocytosis. This may be of considerable interest for intracellular delivery of ligand-associated drugs in anti-angiogenic applications.     

Improving the Secretory Expression of an α-Galactosidase from Aspergillus niger in Pichia pastoris

α-Galactosidases are broadly used in feed, food, chemical, pulp, and pharmaceutical industries. However, there lacks a satisfactory microbial cell factory that is able to produce α-galactosidases efficiently and cost-effectively to date, which prevents these important enzymes from greater application. In this study, the secretory expression of an Aspergillus niger α-galactosidase (AGA) in Pichia pastoris was systematically investigated. Through codon optimization, signal peptide replacement, comparative selection of host strain, and saturation mutagenesis of the P1’ residue of Kex2 protease cleavage site for efficient signal peptide removal, a mutant P. pastoris KM71H (Mut^s) strain of AGA-I with the specific P1’ site substitution (Glu to Ile) demonstrated remarkable extracellular α-galactosidase activity of 1299 U/ml upon a 72 h methanol induction in 2.0 L fermenter. The engineered yeast strain AGA-I demonstrated approximately 12-fold higher extracellular activity compared to the initial P. pastoris strain. To the best of our knowledge, this represents the highest yield and productivity of a secreted α-galactosidase in P. pastoris, thus holding great potential for industrial application.