Effects of glucosidorum tripterygii tororum on cytokine productions in graft-versus-host disease mice

AIM:To observe the effect of glucosidorum tripterygii tororum (GTT) on cytokine productions in acute graft-versus-host disease (aGVHD) mice. METHODS: C₅₇BL/6 mice were exposed to radiation delivered by a linear accelerator. To establish a aGVHD model, the cell suspensions, which were obtained from bone marrow and spleen of the BALB/C mice, were transplanted to the radiated C₅₇BL/6 mice. The recipients were treated with GTT, GTT+CsA and CsA+MTX. The serum concentrations of IL-2, TNF-α, IL-4 and IL-10 were determined by ELISA. RESULTS:The survival rate on day 11 in GTT group (9/10) was higher than in allogeneic bone marrow transplatation (allo-BMT) group (8/19). The concentrations of IL-2 and TNF-α in GTT group were significantly lower, but the concentration of IL-10 was remarkably higher than that in allo-BMT group (P＜0.05). However, the concentration of IL-4 showed no changed in all groups (P＞0.05). CONCLUSION:GTT inhibited aGVHD development by regulating the production of cytokines in the host.     

中间寄主对甘蓝夜蛾赤眼蜂寄生行为的影响

麦蛾卵和米蛾卵作繁蜂寄主对甘蓝夜蛾赤眼蜂G和F两个品系的寄生行为是有影响的。尽管两种卵均可作为甘蓝夜蛾赤眼蜂繁蜂寄主 ,但用米蛾卵繁殖甘蓝夜蛾赤眼蜂比用麦蛾卵繁蜂更好。甘蓝夜蛾赤眼蜂G和F品系在米蛾卵上的总寄生卵量分别为 75.90粒和 67.00粒 ,明显高于在麦蛾卵上的总寄生卵量。用麦蛾卵和米蛾卵作繁蜂寄主 ,将甘蓝夜蛾赤眼蜂G和F品系各 20头进行5d的逐日寄生试验 ,结果表明 :每日平均的寄生卵量、子代羽化率、子代发育历期以及子代性比均随寄生日期的推延而降低。     

甘薯瘟菌系致病型与寄主品种的互作关系

阐述了甘薯瘟菌系致病类型、品种抗性分类、抗性遗传趋势和病菌潜伏侵染特征;介绍了近年来我国南方甘薯瘟病区菌系分布状况,抗病品种利用与抗病育种进展;讨论了病原菌与寄主相互作用中的遗传关系。     

Functional Characterization of Citrus Polygalacturonase-inhibiting Protein

A cDNA encoding a polygalacturonase-inhibiting protein gene (SaiPGIPA) was identified from the citrus cultivar Sainumphung (Citrus sp.), one of the most popular cultivars in northern Thailand. SaiPGIPA was expressed in Escherichia coli cells, and the functional properties of citrus PGIP were analyzed. The PGIP fusion protein inhibited by a maximum of about 60% of the endopolygalacturonase activity, and a mixture of the PGIP and fungal endopoly-galacturonase released oligogalacturonides from polygalacturonic acid. The mixture containing the oligogalactur-onides, endopolygalacturonase and PGIP induced expression of the PGIP gene and a chalcone synthase gene in citrus leaves. The mixture also induced resistance in cucumber leaves against Colletotrichum lagenarium. Received 5 September 2001/ Accepted in revised form 20 November 2001     

中红侧沟茧蜂成虫日龄及粘虫幼虫龄期对寄生效果的影响

室内研究了不同日龄中红侧沟茧蜂成虫对粘虫幼虫龄期的选择、寄主被寄生时的龄期对寄生蜂幼期发育历期和茧重的影响。结果表明：当寄主1～5龄幼虫同时存在时，该蜂可以寄生1—4龄幼虫，不寄生5龄；偏爱寄生2龄和3龄幼虫；对1、2、3和4龄幼虫的选择系数分别为0．21、0．31、0．27和0．21；寄主幼虫供寄生后，其寄生率随寄主幼虫供寄生时的龄期增大而下降。寄生于4龄寄主幼虫的蜂，其卵至结茧的历期显著长于寄生于2或3龄寄主幼虫的蜂；寄生4龄寄主幼虫所育出的蜂茧明显重于寄生于2或3龄寄主幼虫所育出的蜂茧。雌蜂日龄增加，寄生能力下降；但雌蜂日龄对寄生蜂子代卵至结茧的历期和茧重没有影响。     

寄主龄期和温度对管侧沟茧蜂寄生的影响

就管侧沟茧蜂对寄主龄期的选择、生殖能力、成蜂寿命及后代性比进行了研究。结果表明，管侧沟茧蜂偏爱寄生粘虫的1～2龄幼虫，3龄以上幼虫很少被寄生。对1、2、3龄幼虫的选择系数分别为0．42、0．54、0．05。管侧沟茧蜂羽化当天就能交配寄生，在19～25℃条件下单雌平均寄生30头幼虫，最多89头；雌蜂平均寿命6d，最长13d；后代雌雄性比为1：1．02～1：1．27。     

半闭弯尾姬蜂的寄主选择性及寄生对寄主发育和取食的影响

在24℃下研究了半闭弯尾姬蜂寄生对寄主幼虫龄期的选择性及对寄主生长发育、取食量的影响。结果表明，该蜂能寄生小菜蛾2-4龄的幼虫，但当2-4龄幼虫同时存在时，偏爱寄生2、3龄幼虫，对2、3、4龄幼虫的选择系数分别为0．37、0．44、0．19。该蜂对4龄幼虫的寄生能力随寄主日龄增大而下降。2-4龄小菜蛾幼虫被寄生后，总发育历期与预蛹期都比未被寄生的显著延长。当小菜蛾幼虫在2龄初被寄生后，总取食量比未被寄生的显著减少；但当幼虫在3、4龄初被寄生后，各龄的取食量与未被寄生的差异不显著。     

寄主植物对烟粉虱实验种群的影响

本文探讨了不同寄主植物对烟粉虱种群暴发的影响,在28℃恒温下,组建了烟粉虱在甘蓝、番茄、茄子、烟草、黄瓜、辣椒、西葫芦、青菜等8种不同寄主植物上的实验种群生命表.结果表明:烟粉虱对寄主有较强的选择性.烟粉虱在黄瓜、番茄上的产卵量最大，平均每头雌虫分别达382头和246头。各寄主植物上烟粉虱种群内禀增长率在0.2433～0.3790之间，取食番茄的内禀增长率rm最大，达0.3790，不同寄主植物上烟粉虱内禀增长率大小依次为番茄＞甘蓝＞黄瓜＞西葫芦＞茄子＞烟草＞辣椒＞青菜。保护地蔬菜面积扩大是烟粉虱种群暴发的重要原因之一.     

Constraints in implementing biological weed control: A review

Biological weed control is a selective, environment-friendly process, utilizing host-specific control agents towards targeted weeds that prevent damage to non-target crops or native plants. The objective of biological control for weeds is not to eradicate but, rather, to regulate weed populations below levels that cause economic injury. There has been criticism that biological weed control research efforts aim to substitute one purchased input (a bioherbicide) for another (a chemical herbicide). It is essential to remember that 'bioherbicides' and 'biological weed control' are not synonymous. Biological control of weeds involves using any organism to reduce or eliminate the detrimental effects of weed populations, whereas bioherbicides utilize plant pathogens repeatedly. The integration of herbicides, both chemical and biological, into ecologically based weed management is an essential process for the sustainability of agriculture. Throughout this review, the constraints affecting the implementation of biological weed control are described. Greater understanding of the morphology, phenology and genetic diversity of targeted weeds is emphasized and the need to examine all aspects related to biocontrol agents is stressed. Improved technologies, better public support and financial aid, and more scientific interest, will all contribute to the progress of the 'science of biological weed control'.     

Occurrence of viruses in field-grown pepper crops and some of their reservoir weed hosts in Samsun, Turkey

Pepper production is affected by several viral diseases in Samsun, Turkey. To determine the identity of these viruses, a total of 313 samples from field-grown peppers were collected during surveys in 1998 and 1999, and tested by enzyme linked immunosorbent assay (ELISA). Six viruses,Alfalfa mosaic virus (AMV),Cucumber mosaic virus (CMV),Potato virus Y (PVY),Tomato mosaic virus (ToMV),Tobacco mosaic virus (TMV) andTomato spotted wilt virus (TSWV) were detected in the samples. Of 313 plants tested, 42 were doubly infected, and TMV+PVY (15.4%) was the most common double infection. This is also the first report of AMV in pepper fields in Turkey. The effect of some weed species that may act as reservoir of these viruses was also investigated in the region and of 24 weed species belonging to 15 families tested, 16 were found to be infected with at least one virus.Amaranthus retroflexus (Redroot pigweed) appeared to be a common host of CMV, PVY, ToMV, TMV and TSWV, whereasHibiscus trionum (Venice mallow) was recorded as a new weed host of PVY and TSWV. The majority of weed species found to be virus infected were very common in the pepper growing areas of the region. This indicates that pepper fields contaminated with these weeds are under risk of viral infections. http://www.phytoparasitica.org posting July 21, 2005.