A reactive pattern of ischemia-induced nestin protein in the rat brain     

LEI Wan-long  YUAN Qun-fang  DONG Zhi-hong  YAO Zhi-bin 《园艺学报》2002,18(6):639-642

AIM:To explore the expressive profile of nestin protein in the focal ischemic brain and to study the recovery mechanism of brain focal infarct.METHODS:Cellular morphology,time-course and distribution pattern of nestin positive response were immunohistochemically examined in different brain regions of 36 adult male SD rats. RESULTS:Nestin positive response of different brain regions in sham operated rats was present in small- and micro-vasculartures and the third ventricle bottom and ependyma. A large number of nestin positive cells were detected in ischemic brain, and were more remarkable in the cortical areas of parietal lobe and preoptic area as well as ischemic caudoputamen. Stellate nestin positive cells were located in the deep layer of ischemic cortex, but fibrillary cells were located in the shallow layer. Nestin positive cells in the ischemic caudoputamen showed the same changes of morphology as those cells in the deep layer of ischemic cortex. Morphological and number alterations of nestin positive cells were the most remarkable at 1 weeks post-ischemia, which showed more hypertrophy and proliferation in morphology, and a marked increase in number was present in the ischemic cerebral cortex and the ischemic caudoputamen. These alterations of nestin positive cells persisted up to 6 weeks post-ischemia, and then, the nestin positive response in the ischemic brain decreased gradually.CONCLUSION:Focal cerebral ischemia induces nestin re-expression on reactive astrocytes, which may be very important to the self-recovery of cerebral infarct.  相似文献   

Variation of Parthenium hysterophorus in response to soil quality: implications for invasiveness   总被引：1，自引：0，他引：1  

C Annapurna  & J S Singh 《Weed Research》2003,43(3):190-198

Summary The performance of Parthenium hysterophorus , native to the tropical Americas and invasive to several countries, was evaluated for response to soil quality. Phenological (six stages) and quantitative growth variables [relative growth rates in height (R_h) and diameter (R_d)] were measured every fortnight. Based on harvest data, the variables, root:shoot (R:S) ratio, specific leaf area (SLA), relative growth rate in biomass (R_w), net assimilation rate (NAR) and dry matter allocation to plant components, were determined. High clay content in soils prolonged the rosette stage, enhanced R_h and R_d and hampered root growth, but promoted biomass allocation to shoots. The extreme degree of plant mortality was observed, with only 33.3% individuals surviving to reproduce in the soils with highest clay contents. This appears to be one of the most important findings that certainly has a major bearing on the range of adaptation of the weed. Seed mass declined whereas seed production increased in relatively coarser soils with the exception of nearly pure sand. In soils rich in clay, plants produced a smaller number of larger seeds. These data suggest that variation in fundamental functional traits would enable P. hysterophorus to adjust to a variety of habitat conditions.  相似文献   

Leaf, floret and seed infection of wheat by Pyrenophora semeniperda     

M. A. Campbell  R. W. Medd †‡ 《Plant pathology》2003,52(4):437-447

Infection processes of Pyrenophora semeniperda on seedling and adult wheat leaves and wheat ears were investigated. Almost 100% germination of conidia occurred on seedling leaves, compared with 20–30% on adult leaves. Appressoria formed over the anticlinal epidermal cell walls and haloes always accompanied infection. Sometimes papillae formed within the leaves as a resistance mechanism. Infection hyphae ramified through the intercellular spaces of the mesophyll resulting in cellular disruption. The infection processes on floral tissues were similar to those observed on leaves; however, no infection occurred on anther, stigmatic or stylar tissues. Infection of ovarian tissue occurred both with and without appressoria formation. Hyphae grew mainly in the epidermal layers and appeared unable to breach the integumental layer as no growth was observed in endosperm or embryo tissues. The optimum dew period temperature for conidial germination was 23·6°C, compared with 19·9°C for lesion development, 20·4°C for the production of infection structures on seedling leaves and 23·7°C for floret infection. Leaf disease development occurred in a logistic manner in response to dew period, with maximum infection observed after 21 h compared with > 48 h in seeds. An initial dark phase during the dew period was necessary for infection and temperature after the dew period had an effect, with significantly more numerous and larger lesions being formed at 15°C compared with 30°C. Seedling leaves were found to be more susceptible than older leaves, under both field and controlled environment conditions. Infection of wheat seeds following inoculation of ears, or after harvest burial of inoculated disease-free seeds, was demonstrated. In the latter, 3-week-old seedlings were slightly stunted, whereas older plants were unaffected. The apparent unimportance of this plant pathogen as a cause of leaf disease in relation to its poor adaptation to dew periods and dew period temperature is discussed, along with the importance of its seed borne characteristics.  相似文献   

A new approach to evaluate relative resistance and tolerance of tomato cultivars to begomoviruses causing the tomato yellow leaf curl disease in Spain   总被引：1，自引：0，他引：1  

L. Rubio †  J. R. Herrerob  J. Sarrió  P. Morenoa  J. Guerria 《Plant pathology》2003,52(6):763-769

A simple procedure to evaluate relative resistance and tolerance of tomato cultivars to the begomoviruses causing tomato yellow leaf curl (TYLC) disease in Spain was developed. To estimate the resistance and tolerance levels of a cultivar, several formulae were developed based on the ratio of infected plants, virus titre (estimated by tissue–print hybridization) and symptom intensity. The formulae were applied to five commercial tomato cultivars (Amoretto, Birloque, Royesta, Tovigreen and Ulises) naturally infected by TYLC viruses. The analyses showed that Ulises, Birloque and Tovigreen exhibited a moderate resistance, and Ulises was also highly tolerant. There was a positive correlation between symptom intensity and virus titre in infected plants, suggesting that the hybridization technique could also be used as an early estimator of tolerance. Finally, molecular hybridization and nucleotide sequence analyses of the begomovirus intergenic region showed that the local TYLC virus population consisted of a single species, Tomato yellow leaf curl virus (TYLCV, formerly TYLCV-Israel), with low genetic variation (nucleotide identity between isolates higher than 97%).  相似文献   

一个马铃薯Y病毒山东分离物的分离与鉴定   总被引：4，自引：1，他引：4  

王秀芳  朱常香  温孚江  竺晓平  郭兴启 《植物病理学报》2003,33(3):203-208

 从具有典型花叶症状的马铃薯叶片中分离到马铃薯Y病毒(Potato virus Y,PVY)(本文称PVY-SD-TA分离物),扩繁后,提纯病毒,电镜下可观察到700~900 nm×11 nm的病毒粒体,病组织超薄切片观察可见风轮状的内含体结构,寄主反应特性研究表明其能侵染2科13种植物。SDS-PAGE电泳检测病毒编码的外壳蛋白亚基的分子量为33 kDa。以PVY-SD-TA基因组RNA为模板,应用RT-PCR方法和特异引物合成了外壳蛋白基因。对cDNA全序列分析表明,PVY-SD-TA CP基因核苷酸序列与N株系的同源性为96%,与GenBank中登录序列号为AJ390306的O株系分离物的同源性最高,为99%;与国内不同学者报道的PVY中国流行株的同源性分别为96%,97%和98%。通过以上生物学特性和分子水平的研究将PVY-SD-TA鉴定为普通株系(PVY^O株系)。  相似文献   

引起糖甜菜细菌性叶斑病的萎蔫短小杆菌新致病变种   总被引：3，自引：0，他引：3  

陈永芳  郭坚华  方中达 《植物病理学报》2003,33(5):396-400

 1995年在内蒙古临河市新发现了糖甜菜细菌性叶斑病,从病斑所分离的10个细菌菌株经柯赫氏法则验证,均确系该病的病原菌。采用形态观察、表型特征和生理生化特性测定、数值分析、血清学反应、细胞化学成分分析、DNA G+C mol%和DNA-DNA同源性测定进行了鉴定,并与植物病原棒形细菌15个标准菌株进行了比较。该病原菌为革兰氏阳性细菌,不规则短杆状,有一根鞭毛、亚极生或侧生,结合其生理生化特性、细胞化学成分和DNA G+C mol%和DNA-DNA同源性测定结果,认为应属于短小杆菌属(Curtobacterium)的萎蔫短小杆菌(Cur. flaccumfaciens),数值分析也支持这一结论。此外,据血清学反应结果及其对短小杆菌属的其它植物寄主的致病情况,认为该病原菌应是萎蔫短小杆菌种下的一个新的致病变种,定名为Curtobacterium flaccumfaciens pv. beticola pv. nov. Chen et al.,2000(萎蔫短小杆菌糖甜菜致病变种)。  相似文献   

A coat protein transgene from a Scottish isolate of potato mop-top virus mediates strong resistance against Scandinavian isolates which have similar coat protein genes     

Brian Reavy  Maria Sandgren  Hugh Barker  Pekka Heino  Per Oxelfelt 《European journal of plant pathology / European Foundation for Plant Pathology》1997,103(9):829-834

Resistance tests were made on seedlings of transformed lines of Nicotiana benthamiana which contain a transgene encoding the coat protein (CP) gene of a Scottish isolate of potato mop-top virus (PMTV). This transgene has been reported to confer strong resistance to the PMTV isolate from which the transgene sequence was derived and also to a second Scottish isolate. Plants of lines of the transgenic N. benthamiana were as resistant to two Swedish and two Danish PMTV isolates as to a Scottish isolate, and of five lines tested, greater than 93.5% of transgenic plants were immune. The coat protein gene sequences of these four Scandinavian isolates were very similar to those of the two Scottish isolates. The greatest divergence between the isolates was three amino acid changes and there was less than 2% change in CP gene nucleotide sequence. It is concluded that the PMTV CP transgene used in these experiments could confer resistance against isolates from different geographical areas because it is becoming apparent that the CP genes of PMTV isolates are highly conserved.  相似文献   

花粉多糖注射剂质量标准中几个项目测定     

王开发  支崇远  陆明 《蜜蜂杂志》2004,(3):3-4

根据中国药典对注射剂的要求,对花粉多糖的蛋白质、鞣质、树脂、草酸盐、炽灼残渣、钾离子、砷盐、重金属含量进行测定,均符合规定,达到质量标准。  相似文献   

种植方式与种植密度对大力士高粱的影响   总被引：1，自引：0，他引：1  

牟芝兰 《四川草原》2004,(3):27-28

本试验用裂区设计,研究了大力士高粱在16种不同种植密度、3种种植方式下,产草量、生产速度、茎叶比、茎粗的变化情况。结果表明,在撒播密度为18 kg/hm2、条播为22.5 kg/hm2、穴播为28.5 kg/hm2时达到最高产量;生长速度在第53-55 d时最高,达5.7 cm/d;茎叶比随着产量的增加逐渐减少;茎粗随着种植密度的增大而有减小的趋势。  相似文献   

按不同氨基酸模式配制肉鸭日粮的比较研究     

何健  冯光德 《中国家禽》2004,26(4):13-15

试验比较了不同氨基酸模式对肉鸭生产性能的影响。将320只1日龄的樱桃谷鸭随机分为4组,每组80只,设4个重复,每个重复20只,公母各半,分别饲喂四种日粮(按四种氨基酸模式配制),试验期21天。结果表明:日粮的氨基酸模式为Lys∶Met∶Trp∶Thr=100∶45∶21∶62时,其2周和3周体重高于其它各组,但差异不显著(P>0.05),且F/G和血清尿酸水平最低。  相似文献