Colonization and histopathology of susceptible and resistant carnation cultivars infected with Fusarium oxysporum f. sp. dianthi

Stems of the susceptible Early Sam and resistant Novada carnations were inoculated with a conidial suspension ofFusarium oxysporum f. sp.dianthi. Stem segments of either cultivar were sampled regularly and used for determination of fungal growth and for microscopical investigation.Early Sam showed typicalFusarium wilt symptoms and its stems were colonized intensively. The observed vascular browning appeared to be caused by discolouration of primary walls of infected vessels and surrounding cells. Vessels were rarely occluded with gel. Cell wall degradation led to the formation of stem cavities. Hyperplasia of xylem parenchyma was not seen.In Novada, fungal colonization remained low throughout the experiment. Macroscopic symptoms were absent except for longitudinal bursts in the stem, which appeared to be caused by hyperplasia of xylem parenchyma bordering infection. Vascular gelation occurred in the infected tissues, causing some vascular browning also. Xylem vessel regeneration was observed in the hyperplastic layer. Cavities were not formed, and wall discolouration was rare. Vascular gelation is considered part of theFusarium wilt resistance mechanism. It is followed by xylem vessel regeneration, which expresses a general plant response to vascular dysfunction rather than being part of the resistance mechanism.Although of different origin, vascular browning as such occurs in both susceptible and resistant interactions. In breeding for resistance, care should hence be taken with the current use of browning as an indication of disease.Samenvatting Anjers van de vatbare cultivar Early Sam en de resistente cultivar Novada werden geïnoculeerd met een conidiënsuspensie vanFusarium oxysporum f. sp.dianthi. Van beide cultivars werden regelmatig stengeldelen geoogst om deze microscopisch te onderzoeken en om de schimmelgroei te bepalen.Early Sam vertoonde de voor deze verwelkingsziekte kenmerkende symptomen en werd intensief gekoloniseerd. Aan het vaatweefsel waargenomen bruinkleuring bleek veroorzaakt te worden door verkleuring van de primaire wanden van geïnfecteerde vaten en de hen omringende cellen. Zelden trad er in de vaten gomvorming op. Celwandafbraak veroorzaakte de vorming van holten in de stengel. Hyperplasie van het houtparenchym werd niet waargenomen.In Novada bleef de schimmelgroei gedurende het hele experiment beperkt. Macroscopisch waren er enkel lengtescheuren in de stengel te zien, die veroorzaakt bleken te worden door hyperplasie van aan de infectie grenzend houtparenchym. In het geïnfecteerde vaatweefsel optredende gomvorming veroorzaakte ook enige bruinkleuring. In het hyperplastische weefsel werd regeneratie van houtvaten waargenomen. In de stengel werden geen holten gevormd, en verkleuring van de celwanden kwam weinig voor. De vorming van gommen in de houtvaten maakt waarschijnlijk deel uit van het resistentiemechanisme. De daarop volgende houtvatregeneratie is eerder een algemene reactie van de plant op vaatverstopping dan een deel van het resistentiemechanisme.Vaatverbruining, zij het van verschillende oorsprong, komt voor in zowel vatbare als resistente interacties. Om die reden moet men in de resistentieveredeling bij de anjer voorzichtig zijn met het gebruik van bruinkleuring als ziekteïndicatie.     

Biochemical properties of the pathogenesis-related proteins from tobacco

This review describes the discovery and identification of the pathogenesis-related proteins (PRs) from tobacco. In crude leaf extracts the PRs are distinguished from the proteins in uninfected plants by their solubility at pH 3, resistance to a range of proteases, and mobility in polyacrylamide gels upon electrophoresis (PAGE) in non-denaturing conditions. PAGE has been used as a qualitative and semi-quantitative assay for PRs, and their migration in gels made from different acrylamide concentrations has been used to identify charge and size isomers and electrophoretically identical PRs in different tobacco cultivars. The subunit composition and molecular weight (mol. wt) of the four PRs identified first in Xanthi-nc were determined by SDS-PAGE; staining the gels has shown that these same four proteins in Samsun NN did not contain carbohydrate, lipid or nucleic acid, nor were they isozymic forms of twenty five enzymes known to increase in activity following infection with TMV. Evidence suggests that most of the PRs in Xanthi-nc and Samsun NN are extracellular.The purification of several PRs from Xanthi-nc, Samsun NN and other tobaccos is described, as well as their mol. wt, subunit and amino acid composition. PRs 1a, b and c consist of a single polypeptide and have similar mol. wt and amino acid compositions. Antisera prepared against purified Xanthi-nc b₁ protein have been used to determine serological relationships between PRs and form the basis of a very sensitive quantitative assay using ELISA. The regulation of synthesis of some PRs has been shown to involve translational control.     

Selection and amplification of the liver stem cell subset from rat bone marrow cells with a medium containing cholestatic serum in vitro

AIM: To explore the feasibility of direct separat and selective enlargement of the bone marrow-derived liver stem cells (BDLSC) from bone marrow cells with a culture system containing cholestatic serum in vitro. METHODS: Bone marrow cells of rats were cultured with selective media containing 2%, 5%, 7% and 10% cholestatic rat serum, respectively. The BDLSC were then induced to proliferate with the addition of hepatocyte growth factor (HGF) on the firth day. BDLSC were characterized using immunocytochemistry and RT-PCR for lineage markers, glycogen staining and urea synthetic assay for functions 2 weeks later. RESULTS: Bone marrow cells were unble to form colony in the presence of 2% cholestatic serum and apopotosis appeared gradually in 7% or 10% cholestatic serum. The BDLSC survived in the medium containing 5% cholestatic serum while the other types of cells did not. The survival cells proliferated with a high speed during the second week and then formed hepatocyte-like colony-forming units (H-CFU). Cells in the H-CFU expressed the characteristic proteins of fetal hepatocytes. Furthermore, they had glycogen storage and urea synthesis functions, two of the critical features of hepatocytes. CONCLUSION: The selective micro-environment effectively selected BDLSC from the bone marrow cell, and will be a new way to provide an abundant source of donor hepatocytes for clinical cell therapy.     

湖南猪致病性大肠杆菌的分离及药物敏感性监测

从湖南47个规模化猪场发生典型仔猪黄、白痢猪只的63份腹泻病猪分离出63株大肠杆菌，其中12株作致病力试验均有致病性，对25种抗菌药物药敏试验，大肠杆菌对胺卡那霉素和头孢唑啉敏感，敏感菌株分别占98．41％和92．06％；多种抗生素产生耐药性，且为多重耐药。     

TFSQ型高效环保组合式粮食杂质清理筛的研制

通过对振动筛理、垂直风选、旋风分离与沉降系统的研究,研制出集振动筛理、风选、旋风分离沉降、含尘气流循环再利用为一体的TFSQ型高效环保组合式粮食杂质清理筛。经应用测试和专家鉴定:该设备具有清理效率高、清理过程粉尘污染小,使用维护方便、可靠性强等优点,具有广阔的市场推广前景。     

江浙地区葡萄霜霉病菌的致病性差异研究

为明确江苏、浙江不同地区葡萄霜霉病菌的致病性分化情况,采用单斑分离法和叶盘接种法,对分离得到的不同葡萄霜霉病菌单斑菌株进行致病性测定。结果表明,分离获得的80个葡萄霜霉病菌株都有致病性,且2个省份均有半数以上的菌株的病情指数在40~60之间。致病力聚类分析表明,2个省份的菌株都可以聚类为强、中、弱3种致病力类型,江苏以强致病力菌株为优势菌株,浙江以中等致病力菌株为优势菌株。对同一省份的菌株进行致病力分析发现,江苏树山和浙江永福的菌株致病力明显强于同省其他地区,而江苏新坊和浙江上钱的菌株与同省其他地区相比,致病力最弱。同时,构建菌株的系统发育树,结果显示,同源性相同的菌株间有致病力不同的情况,致病力相同的菌株间也存在rDNA-ITS序列有差异的情况。综上,江苏、浙江的葡萄霜霉病菌都存在致病力分化现象,这种分化现象与菌株的亲缘关系远近没有相关性,但同一省份不同地区间的菌株致病力差异与菌株的地理来源有一定的相关性。     

诱导Paracin1.7生成的刺激因子的分离与纯化

旨在分离纯化枯草芽孢杆菌(Bacillus subtilis)中能够诱导细菌素Paracin1.7分泌的刺激因子,并探明其对副干酪乳杆菌(Lactobacillus paracasei) HD1.7细菌素生成量及群体感应相关基因luxS表达的影响。本研究通过60%硫酸铵沉淀、CM Sepharose Fast Flow弱阳离子交换柱层析中度纯化及Superdex 75凝胶层析精度纯化,将获得的层析分离物与L. paracasei HD1.7共培养,检测共培养发酵液的抑菌活性及luxS基因的转录水平,并用SDS-PAGE与Native-PAGE检测分离物质。结果表明L. paracasei HD1.7抑菌活性为126.68%;luxS基因上调表达,为对照菌株的2.43倍;刺激因子的表观分子量约为30 kDa。本研究利用三步法初步分离纯化出诱导Paracin1.7生成的刺激因子,明确该刺激因子可以启动种间群体感应相关基因luxS,为L. paracasei HD1.7的群体感应研究奠定了理论和技术基础。     

葡萄种植中土石分离混料机的设计——基于TRIZ理论

针对宁夏贺兰山东麓葡萄种植基地,葡萄种植定值沟的挖掘作业步骤繁琐、耗费时间长,劳动强度大、工作效率低等现状,基于TRIZ理论并运用技术矛盾冲突设计了土石分离混料机。该机是集土石分离、土壤与农家肥混合并回填定植沟等作业同步进行的机械设备,彻底改变了人工捡石、施肥、旋耕、机械挖掘等传统的作业模式,大大节省了人力、物力,并提高了葡萄种植定植沟挖掘作业的工作效率。     

An improved method for extraction of sorghum polymeric protein complexes

A method for fractionating sorghum proteins using extraction solvents and techniques designed to obtain polymeric protein structures (especially disulfide linked) was developed. Extraction and separation conditions were optimized in terms of completeness of protein extraction, sample stability, and analytical resolution. After pre-extraction of albumins and globulins, a 3-step sequential procedure involving no reducing agents was applied to ground whole sorghum flour. The three fractions obtained represented proportionally different protein polymer contents and molecular weight distribution as evidenced by comparative size exclusion chromatography. Protein composition also varied among the extracts with differences in kafirin composition and non-kafirin proteins detected in the fractions by RP-HPLC and SDS-PAGE analysis. The ability to quantify and further characterize sorghum polymeric protein complexes will be useful for additional studies linking protein structures with functionality and digestibility and variations for these properties within diverse sorghum germplasm.     

三峡大学校园垃圾分类回收现状及回收机制的建立探讨

指出了垃圾分类回收具有重要的意义，有利于资源节约型和环境友好型社会的建设，有利于循环经济的可持续发展。分析了校园垃圾分类回收现状，对建立校园分类回收机制进行了探讨。