韧皮部运输和防御作用的分子机理

韧皮部是维管系统的重要组成部分,在物质运输、信息传递、机械支持以及防御作用中发挥重要作用。近年来,在建立了一系列研究方法的基础上,对韧皮部运输和防御功能特别是碳水化合物装载和卸出机理进行了大量研究,克隆出一些特异基因,初步阐明了韧皮部装载的分子机制,取得可喜进展。本文综述了一些相关研究结果,并提出几个有待解决的问题     

小麦目标产量设计及适宜品种选择的动态知识模型

运用知识工程和系统建模方法,在综合考虑决策点光温生产潜力、历史平均产量水平、土壤肥力、肥水管理水平和生产技术水平等诸多因子对增产系数影响的基础上,通过定量计算动态增产系数,建立了具有时空适应性的小麦目标产量设计知识模型;通过定量计算小麦品种特征值与环境因子和生产需求之间的符合度,建立了适宜品种选择的量化知识模型．利用南京、郑州、泰安、保定和太原5个不同生态点的不同年型每日气象资料以及不同历史平均产量水平、土壤肥力和肥水管理水平,对目标产量设计模型进行了实例分析;利用广州、南京、泰安、北京、哈尔滨5个不同生态点常年气象资料以及15个不同品种资料,对品种选择知识模型进行了实例分析．结果表明,所建知识模型具有较好的决策性和广泛适应性．     

Inhibition of protein kinase A in murine enteric neurons causes lethal intestinal pseudo‐obstruction

A number of in vitro studies suggest that many important developmental and functional events in the enteric nervous system are regulated by the intracellular signaling enzyme cAMP protein kinase A (PKA). To evaluate the in vivo significance of these observations, a Cre‐inducible, dominant‐negative, mutant regulatory subunit (RIαB) of PKA was activated in enteric neurons by either a Proteolipid protein‐Cre transgene or a Hox11L1‐Cre “knock‐in” allele. In both models, RIαB activation resulted consistently in profound distension of the proximal small intestine within 2 weeks after birth. Intestinal transit of radio‐opaque tracers was severely retarded in the double‐transgenic animals, which died shortly after weaning. In the enteric nervous system, recombination was restricted to neurons as demonstrated by histochemical analysis and confocal microscopic colocalization of a Cre recombinase‐dependent reporter gene with the neuronal marker Hu(C/D), in contrast with the glial marker S100. Histochemical analysis of β‐galactosidase expression and acetylcholinesterase activity, as well as neuronal counts, demonstrated that intestinal dysmotility was not associated with obvious malformation of the myenteric plexus. However, inhibition of PKA activity in enteric neurons disrupted the major motor complexes of isolated intestinal segments in vitro. These results provide strong evidence that PKA activity plays a critical role in enteric neurotransmission in vivo, and highlight neuronal PKA or related signaling molecules as potential therapeutic targets in gastrointestinal motility disorders. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2006     

Isolation and characterization of a novel thermostable non-specific lipid transfer protein-like antimicrobial protein from motherwort (Leonurus japonicus Houtt) seeds

In screening for potent antimicrobial proteins from plant seeds, a novel heat-stable antimicrobial protein, designated LJAMP2, was purified from seeds of the motherwort (Leonurus japonicus Houtt), a medicine herb, with a procedure involving cation exchange chromatography on a CM FF column, and reverse phase HPLCs on C8 column and C18 column. LJAMP2 exhibited a molecular mass of 6.2 kDa determined. Automated Edman degradation determined the partial N-terminal sequence of LJAMP2 to be NH2-AIGCNTVASKMAPCLPYVTGKGPLGGCCGGVKGLIDAARTTPDRQAVCNCLKTLAKSYSG, which displays homology with plant non-specific lipid transfer proteins (nsLTPs). In vitro bioassays showed that LJAMP2 inhibits the growth of a variety of microbes, including filamentous fungi, bacteria and yeast. The growth of three phytopathogenic fungi, Alternaria brassicae, Botrytis maydis, and Rhizoctonia cerealis, are inhibited at 7.5 μM of LJAMP2, whereas Bacillus subtilis is about 15 μM. The IC₅₀ of LJAMP2 for Aspergillus niger, B. maydis, Fusarium oxysporum, Penicillium digitatum and Saccharomyces cerevisiae are 5.5, 6.1, 9.3, 40.0, and 76.0 μM, respectively.     

浙江省首例人禽流感病例的病原学与分子生物学研究

为确认浙江省首例疑似人禽流感病例,进行病原学分析,对患者气管吸出物进行核酸RT-PCR、荧光定量RT-PCR检测以及病毒分离,并对患者血清进行HI抗体测定.结果表明患者气管吸出物H5N1亚型和A型流感病毒特异核酸均呈阳性,分离到禽流感病毒A/Zhejiang/16/06(H5N1)株;双份血清中禽流感病毒(H5N1)HI抗体滴度分别为1320和1640,从病原学和血清学上证实为人禽流感病例.分离毒株测序结果显示,A/Zhejiang/16/06(H5N1)株在HA裂解位点为多个碱性氨基酸,符合高致病性禽流感病毒特征;该毒株的HA、NA、PB2、NP、M和NS基因序列均为禽源,与2005年我国福建、安徽等地禽流感病毒分离株高度同源,而与越南、泰国以及香港1997年分离到的禽流感病毒株之间存在明显差异.     

Which RhD alleles are risk factors stimulating allo- anti-D?

The aim of this study was to identify the specific RhD alleles that are risk factors for stimulating allo-anti-D and develop a precise strategy for blood transfusion. To confirm the D phenotype, red blood cells suspended in saline should react to serological anti-D from three manufacturers. An antibody screen test, a saline phase test and a micro-column test were conducted to identify allo-anti-D and other allo-antibodies. RhD alleles were genotyped by PCR using sequence-specific primers. Seven hundred subjects who were either pregnant or had undergone transfusion were enrolled in our study; however, 28 samples were excluded because their RhD alleles were normal, as revealed by tests using genotyping kits. A total of 498 cases (74.1%) were RhD-null (lacking exons 1–10 of RhD), 336 were DEL RhD 1227A (20.2%), and 38 were RHD-CE (2-9) -D (5.6%). There were 136 cases (20.2%) with allo-anti-D among the 672 cases, with an allo-anti-D prevalence of 126 cases (25.3%) in 498 cases that were RhD-null, followed by 10 cases (26.3%) among 38 cases with RHD-CE (2-9) -D, and none in 366 cases with RhD1227A. RhD genetic polymorphism was observed in RhD-negative individuals. We concluded that RhD-null and partial D are risk factors for alloimmunization to the D antigen and should be transfused with Rh-negative blood. RHD1227A recipients can be transfused with RhD-positive blood. Pregnant women with the d/d and D-CE(2-9)-D alleles require appropriate anti-D prophylaxis and RhD1227A may induce a higher tolerance.     

A small zinc finger thylakoid protein plays a role in maintenance of photosystem II in Arabidopsis thaliana

This work identifies LOW QUANTUM YIELD OF PHOTOSYSTEM II1 (LQY1), a Zn finger protein that shows disulfide isomerase activity, interacts with the photosystem II (PSII) core complex, and may act in repair of photodamaged PSII complexes. Two mutants of an unannotated small Zn finger containing a thylakoid membrane protein of Arabidopsis thaliana (At1g75690; LQY1) were found to have a lower quantum yield of PSII photochemistry and reduced PSII electron transport rate following high-light treatment. The mutants dissipate more excess excitation energy via nonphotochemical pathways than wild type, and they also display elevated accumulation of reactive oxygen species under high light. After high-light treatment, the mutants have less PSII-light-harvesting complex II supercomplex than wild-type plants. Analysis of thylakoid membrane protein complexes showed that wild-type LQY1 protein comigrates with the PSII core monomer and the CP43-less PSII monomer (a marker for ongoing PSII repair and reassembly). PSII repair and reassembly involve the breakage and formation of disulfide bonds among PSII proteins. Interestingly, the recombinant LQY1 protein demonstrates a protein disulfide isomerase activity. LQY1 is more abundant in stroma-exposed thylakoids, where key steps of PSII repair and reassembly take place. The absence of the LQY1 protein accelerates turnover and synthesis of PSII reaction center protein D1. These results suggest that the LQY1 protein may be involved in maintaining PSII activity under high light by regulating repair and reassembly of PSII complexes.     

Analysis of fatty acids in A. szechenyianum Gay. by microwave‐assisted extraction and gas chromatography‐mass spectrometry

Introduction – Aconitum szechenyianum Gay. is a traditional Chinese medicinal herb with the detumescent and styptic effects and antitumor activity. There have been only a few researches on its chemical components, but no detailed report has appeared on its fatty acids. Objective – To develop a simple and effective method for the extraction of fatty acids from A. zechenyianum Gay. and then to investigate the fatty acid components. Methodology – Microwave‐assisted extraction (MAE) was optimized with response surface methodology, and the fatty acid compositions of extract were determined by GC–MS with previous derivatisation to fatty acid methyl esters (FAMEs). The results were compared with that obtained by classical Soxhlet extraction (SE). Results – Compared with SE, MAE showed significantly higher fatty acid yields, shorter extraction time, and lower energy and solvent consumption. The major fatty acids in A. szechenyianum Gay. are linoleic acid, palmitic acid, linolenic acid, oleic acid and stearic acid, and the unsaturated fatty acids occupy 66.4% of the total fatty acids. Copyright © 2010 John Wiley & Sons, Ltd.     

Crocodilian phylogeny inferred from twelve mitochondrial protein-coding genes, with new complete mitochondrial genomic sequences for Crocodylus acutus and Crocodylus novaeguineae

We report complete mitochondrial genomic sequences for Crocodylus acutus and Crocodylus novaeguineae, whose gene orders match those of other crocodilians. Phylogenetic analyses based on the sequences of 12 mitochondrial protein-coding genes support monophyly of two crocodilian taxonomic families, Alligatoridae (genera Alligator, Caiman, and Paleosuchus) and Crocodylidae (genera Crocodylus, Gavialis, Mecistops, Osteolaemus, and Tomistoma). Our results are consistent with monophyly of all crocodilian genera. Within Alligatoridae, genus Alligator is the sister taxon of a clade comprising Caiman and Paleosuchus. Within Crocodylidae, the basal phylogenetic split separates a clade comprising Gavialis and Tomistoma from a clade comprising Crocodylus, Mecistops, and Osteolaemus. Mecistops and Osteolaemus form the sister taxon to Crocodylus. Within Crocodylus, we sampled five Indopacific species, whose phylogenetic ordering is ((C. mindorensis, C. novaeguineae), (C. porosus, (C. siamensis, C. palustris))). The African species C. niloticus and New World species C. acutus form the sister taxon to the Indopacific species, although our sampling lacks three other New World species and an Australian species of Crocodylus.