植物病毒病的诊断技术

植物病毒病是一种全球性的病害,每年全世界由植物病毒病造成的农作物损失估计高达１５０亿美元。植物病毒病的准确诊断有利于病毒病的综合防治。近年来,由于植物病毒分类体系的逐步完善,以及病毒鉴定技术的不断进步,植物病毒病的诊断方法有很大发展。本文介绍植物病毒诊断技术的发展现状。１生物学鉴定 利用生物学鉴定进行植物病毒病的诊断,主要依据寄主植物和病毒的传播方式。寄主植物诊断的方法主要包括利用寄主病症、寄主范围和交叉保护现象。在早期的植物病毒研究中,病毒检测和鉴定是以病症为主要根据,现证实这不太可靠［１］,…     

植物病原细菌无毒基因与植物抗病性

植物诱导的防卫反应种类繁多 ,其中包括活性氧水平升高、植物抗毒素 (ｐｈｙｔｏａｌｅｘ ｉｎ)的生物合成、水解酶类和抑制蛋白的释放 ,以及超过敏性反应 (ｈｙｐｅｒｓｅｎｓｉｔｉｖｅｒｅ ｓｐｏｎｓｅ ,ＨＲ)等。ＨＲ被认为是植物对病原体抗性的一种普遍表现形式 ,是病原菌无毒基因 (ａｖｉｒｕｌｅｎｃｅｇｅｎｅ,简称ａｖｒ基因 )产生的诱导剂与植物抗性基因 (ｒｅｓｉｓｔａｎｃｅｇｅｎｅ ,Ｒ基因)产生的受体之间相互识别的结果。ａｖｒ基因是植物病原体中决定对带有相应抗病基因的寄主植物特异的不亲和无毒性基因。Ｓｔａｓｋａｕ…     

脂联素的研究进展及与多种疾病的关系

超重和肥胖对心血管疾病,糖尿病及其它疾病的发生发展及预后有着重要的意义。脂联素是脂肪细胞介导的分泌蛋白,在体内和体外的大量实验中,都被证实具有多种功能:抗炎、改善胰岛素抵抗、抗动脉粥样硬化、降血糖、降血脂、抗氧化等。作为生物标记物,脂联素在临床研究中受到广泛关注。根据最新的研究结果,本文简要的介绍了脂联素的主要结构特征,作用机制,参与胰岛μ细胞的功能和存活、胰岛素抵抗的作用,以及与多种疾病之间的关系。作为唯一一个在肥胖患者体内水平下调的脂肪因子,脂联素对肥胖症、糖尿病、心血管疾病、肾脏疾病的保护作用及其分子机制的研究具有深远的意义,为相关疾病的预防和治疗提供新的思路。同时相关研究也为药物治疗提供可靠的下游靶点。     

A Pathway-Based View of Human Diseases and Disease Relationships

It is increasingly evident that human diseases are not isolated from each other. Understanding how different diseases are related to each other based on the underlying biology could provide new insights into disease etiology, classification, and shared biological mechanisms. We have taken a computational approach to studying disease relationships through 1) systematic identification of disease associated genes by literature mining, 2) associating diseases to biological pathways where disease genes are enriched, and 3) linking diseases together based on shared pathways. We identified 4,195 candidate disease associated genes for 1028 diseases. On average, about 50% of disease associated genes of a disease are statistically mapped to pathways. We generated a disease network which consists of 591 diseases and 6,931 disease relationships. We examined properties of this network and provided examples of novel disease relationships which cannot be readily captured through simple literature search or gene overlap analysis. Our results could potentially provide insights into the design of novel, pathway-guided therapeutic interventions for diseases.     

关于防治肝病的植物资源

肝是人体中最大的消化腺 ,肝细胞分泌胆汁有助于脂肪的消化和吸收 ,肝细胞内进行着蛋白质、脂肪和糖的各种代谢活动 ,同时肝还是人体内主要的解毒器官。正因为肝脏的重要性 ,因而其发病轻则影响正常生活 ,重则危及生命。肝病常见的有病毒性肝炎、脂肪肝、肝脓肿、肝硬化和肝癌等。肝病在我国的发病率是很高的 ,目前许多国内外专家学者致力于攻克这一顽症的研究。为了维护人类的健康 ,防治肝病 ,力求从大量植物中寻找治疗肝病的植物资源是其中重要的一种途径 ,现在此简介几种。1.　鸡骨草 (ＡｂｒｕｓｃａｎｔｏｎｉｅｎｓｉｓＨａｎｃｅ)鸡…     

幽影病毒引起的几种主要植物病害

幽影病毒的基因组不编码外壳蛋白,不形成通常的病毒粒体结构。这类病毒往往和黄症病毒复合侵染引起植物病害,蚜虫传播是病害在田间传播流行的主要方式。对幽影病毒引起的胡萝卜杂色矮缩病、花生丛簇病以及烟草丛顶病等几种主要病害的症状、发生与危害、病原物特性以及病害的控制等进行了综述。     

植物病害免疫学诊断技术

植物病害免疫学诊断技术将以抗原和抗体的特异性反应为基础的传统免疫学继承并发展,应用于植物病害的诊断上.最近10几年,植物病害免疫学诊断技术已广泛应用到病原真菌的检测中.免疫学诊断方法分为非标记免疫分析方法和标记免疫分析方法两大类.着重介绍了应用于植物病害免疫学诊断技术中的酶联免疫吸附测定、免疫胶体金快速诊断技术.     

植物体表与昆虫的关系

昆虫与植物的关系是当前昆虫学研究中十分活跃的领域。昆虫与植物之间的相互作用首先发生于植物体表。植物体表是植物与其生物和物理环境之间的界面,是一个功能器官,其结构的多样化是植物遭受环境压力多样化的反映。许多特性是植物与昆虫相互作用的结果［１５］。植物不...     

遥感技术对早期植物病毒病的诊断

本文讨论了利用遥感技术对植物病毒病早期诊断的实验研究。试验表明,该方法对植物病毒的检测是很敏感的。本研究结果为今后利用航空、卫星遥感进行大面积植物病害的监测提供了依据。     

Relationships of Histones to RNA Synthesis in Plant Tissues

The RNA-synthesizing activity of the tissue, template activity of the chromatin, histones and other parameters were analyzed for young leaves, senescent leaves and the pith tissue of tobacco. The amount, of RNA, DNA and the extent of incorporation of ³²P into RNA was much lower in old leaves and the pith tissue than in young leaves. Furthermore, the ³²P sucrose density gradient patterns of RNA from the three tissues were very different. In old leaves, the label was found mostly in low molecular weight RNA region, presumably as a result of degradation of RNA by soluble and chromatin-associated ribonucleases which were higher in old leaves. — In addition to significant differences in the composition of chromatin, large differences in the ratios of F_I : F_II : F_III : : histone fractions from the three tissues were noted and the fully differentiated old leaves and the pith tissue had proportionately more F_IIand F_III histones than the less differentiated young leaves. The F_III histone of tobacco differed from that of pea and calf thymus in having lys/arg = 1.2. — Although some correlation between RNA-synthesizing activity of the tissue, template activity of chromatin and the histone composition was noted for the pith tissue and the young leaves, the situation with old leaves was more complicated, probably due to the occurrence of chromatin-associated deoxyribonuclease and involvement of other factors which may also effect RNA synthesis.     

The Use of Canonical Correlation Analysis in the Investigation of Relationships Between Plant Growth and Environmental Factors

The relationship between environmental factors and growth inImpatiens parviflora was analysed by the method of canonicalcorrelation analysis. The method was able to identify the majorrelationships which had been detected by conventional methodsof analysis. The method was also able to detect relationshipsnot identified by conventional methods. The canonical correlationanalysis also clearly showed that relationships between growthand environment detected at a plant dry weight of 100 mg couldalso be detected at 300 mg despite masking due to ontogeneticdrift and confusion by different patterns of adaptation. Itis concluded that the method of canonical correlation analysisis most useful for the analysis of considerable bodies of datarelating plant growth to environmental factors. Marked effectsof spectral composition on growth and development of both leavesand stems were demonstrated. Different spectral compositioneffects on hypocotyl and internode elongation exist. Impatiens parviflora, growth analysis, canonical correlation analysis, spectral composition, stemelongation     

Phylogenomics and Coalescent Analyses Resolve Extant Seed Plant Relationships

The extant seed plants include more than 260,000 species that belong to five main lineages: angiosperms, conifers, cycads, Ginkgo, and gnetophytes. Despite tremendous effort using molecular data, phylogenetic relationships among these five lineages remain uncertain. Here, we provide the first broad coalescent-based species tree estimation of seed plants using genome-scale nuclear and plastid data By incorporating 305 nuclear genes and 47 plastid genes from 14 species, we identify that i) extant gymnosperms (i.e., conifers, cycads, Ginkgo, and gnetophytes) are monophyletic, ii) gnetophytes exhibit discordant placements within conifers between their nuclear and plastid genomes, and iii) cycads plus Ginkgo form a clade that is sister to all remaining extant gymnosperms. We additionally observe that the placement of Ginkgo inferred from coalescent analyses is congruent across different nucleotide rate partitions. In contrast, the standard concatenation method produces strongly supported, but incongruent placements of Ginkgo between slow- and fast-evolving sites. Specifically, fast-evolving sites yield relationships in conflict with coalescent analyses. We hypothesize that this incongruence may be related to the way in which concatenation methods treat sites with elevated nucleotide substitution rates. More empirical and simulation investigations are needed to understand this potential weakness of concatenation methods.     

Modulation of Plant Resistance to Diseases by Water-Soluble Chitosan

Low-molecular-weight water-soluble chitosan (5 kDa) obtained after enzymatic hydrolysis of native crab chitosan was shown to display an elicitor activity by inducing the local and systemic resistance of Solanum tuberosum potato and Lycopesicon esculentum tomato to Phytophthora infestans and nematodes, respectively. Chitosan induced the accumulation of phytoalexins in tissues of host plants; decreased the total content; changed the composition of free sterols producing adverse effects on infesters; activated chitinases, -glucanases, and lipoxygenases; and stimulated the generation of reactive oxygen species. The activation of protective mechanisms in plant tissues inhibited the growth of taxonomically different pathogens (parasitic fungus Phytophthora infestans and root knot nematode Meloidogyne incognita).