Expression of natural killer cell stimulatory receptor NKG2D and its ligand MICA in Tibetan patients with gastric cancer at Qinghai plateau

AIM: To investigate the expression of natural killer cell stimulation receptor D(NKG2D) in peripheral blood and the expression of major histocompatibility complex class I chain-related protein A(MICA) on the gastric carcinoma tissue and the neighboring non-cancerous tissue in Tibetan patients with gastric cancer at Qinghai plateau. METHODS: Samples of 33 patients and 20 healthy persons were collected to detect NKG2D in peripheral blood by Flow cytometry analysis. The expressions of MICA in part of the correspondent tissues were examined by RT-PCR and immunohistochemistry.RESULTS: The expression of NKG2D in the plateau of Tibetan patients with gastric cancer group (13.47 ±5.26)% was significantly lower than that in healthy groups (32.62±10.08)%. The mRNA level of MICA in gastric cancer was significantly higher than that in neighboring non-cancerous tissue (P<0.05). The expressions of MICA proteins showed a significant difference between the neighboring non-cancerous tissue (21.21%, 7/33) and the gastric carcinoma tissue (78.79%, 26/33), between the high differentiation (60.00%, 3/5) and the moderate (72.73%, 8/11), low differentiation (88.24%, 15/17). The expressions of MICA were not correlated with tumor size, sex, age, lymph node metastasis of the patients (P>0.05). Spearman rank correlation displayed that the expressions of MICA mRNA were positively correlated with the MICA protein level (r=0.903, P<0.01).CONCLUSION: The immune escape in Tibetan patients with gastric cancer at Qinghai plateau probably relates to the down-regulation of NKG2D and the up-regulation of its ligand MICA. The activity of NK cells and the anti-cancer cellular immunity level are descending in the plateau of Tibetan patients with gastric cancer. The decrease in the receptor NKG2D is a reason for the activity of NK cell descending.     

野生稻与栽培稻的杂种后代对褐稻虱的抗性机制初探

为了开拓抗虫基因源,培育抗性稳定的水稻抗虫品种,采用感虫的栽培稻雄性不育株为母本,以高抗褐稻虱的野生稻为父本进行有性杂交。通过用改良的苗期群体筛选法,对其后代进行抗性鉴定,证实其抗性可以遗传,已成功地获得了抗褐稻虱的杂种后代。并根据飞虱在抗虫植株上的生存率、群体建立、蜜露量和稻株的受害级别等指标与感虫对照种TN1上的差异显著性作比较,综合评定杂种后代对褐稻虱的抗性机制。结果表明,测试的N482(A)/101392组合的F_5、F_6、F_7和H_4等几个后代对褐稻虱的抗性机制均为抗生性。     

转hrf1基因水稻对稻曲病抗性分析

用注射接种法测定9个转hrf1基因水稻品系对稻曲病的抗性,结果表明B12-2m、B12、HTRP2和NJH12转基因系对稻曲病的抗性有显著提高,其中NJH12对稻曲病的抗性表现最突出。在江苏南京和安徽潜山两地的田间测定结果显示NJH12对稻曲病的抗性表现明显,与对照相比防效提高65%以上。用RT-PCR测定抗病转基因系中防卫基因的表达,在抗病转基因系中,Ospr1a、Ospr1b和PAL等防卫反应基因的表达明显增强。转hrf1基因水稻可能通过诱导防卫反应基因的表达提高水稻对稻曲病的抗性。     

中国水稻害虫治理对策的演变及其展望

本文简要回顾了中国水稻害虫的变迁、相应的对策演变,从中了解、总结害虫发生与人类治虫对策之间的因果渊源,指出只有师法自然、通过生态工程实施生态治理技术才能持续双赢。     

8个WRKY转录因子在水稻叶片生长和抗病过程中的表达分析

 WRKY是植物体内最大的转录因子家族之一, 其成员在植物生长发育和抗逆过程中发挥重要作用。为了解水稻WRKY的功能, 本研究利用蛋白质免疫印迹(western blotting, WB)技术, 检测了8个WRKY转录因子在水稻叶片生长和Xa21介导的抗白叶枯病过程中的表达丰度变化。结果表明:OsWRKY12、43、55和86在苗期表达量较低, 随叶片的生长表达逐步增加;OsWRKY50和84在苗期叶片中的表达量相对较高, 成熟期下降;未检测到OsWRKY40/64和52在叶片中的表达。在Xa21介导的白叶枯病抗性反应中, OsWRKY40/64、50和52受白叶枯病菌诱导表达, OsWRKY84受侵染后表达量上调, OsWRKY12、43、55和86在抗病过程中没有检测到表达丰度的变化。进一步比较这些转录因子在抗、感和对照(Mock)反应中的表达, 发现抗、感反应间蛋白质的表达变化是相似的。研究结果提示:OsWRKY12、43、55和86可能在叶片正常生长中发挥作用;OsWRKY40/64和52可能在水稻-白叶枯病菌互作过程中发挥作用;OsWRKY50和84则在叶片生长和抗白叶枯病过程中都有一定的功能。     

Allelopathy in crop/weed interactions--an update

Since varietal differences in allelopathy of crops against weeds were discovered in the 1970s, much research has documented the potential that allelopathic crops offer for integrated weed management with substantially reduced herbicide rates. Research groups worldwide have identified several crop species possessing potent allelopathic interference mediated by root exudation of allelochemicals. Rice, wheat, barley and sorghum have attracted most attention. Past research focused on germplasm screening for elite allelopathic cultivars and the identification of the allelochemicals involved. Based on this, traditional breeding efforts were initiated in rice and wheat to breed agronomically acceptable, weed-suppressive cultivars with improved allelopathic interference. Promising suppressive crosses are under investigation. Molecular approaches have elucidated the genetics of allelopathy by QTL mapping which associated the trait in rice and wheat with several chromosomes and suggested the involvement of several allelochemicals. Potentially important compounds that are constitutively secreted from roots have been identified in all crop species under investigation. Biosynthesis and exudation of these metabolites follow a distinct temporal pattern and can be induced by biotic and abiotic factors. The current state of knowledge suggests that allelopathy involves fluctuating mixtures of allelochemicals and their metabolites as regulated by genotype and developmental stage of the producing plant, environment, cultivation and signalling effects, as well as the chemical or microbial turnover of compounds in the rhizosphere. Functional genomics is being applied to identify genes involved in biosynthesis of several identified allelochemicals, providing the potential to improve allelopathy by molecular breeding. The dynamics of crop allelopathy, inducible processes and plant signalling is gaining growing attention; however, future research should also consider allelochemical release mechanisms, persistence, selectivity and modes of action, as well as consequences of improved crop allelopathy on plant physiology, the environment and management strategies. Creation of weed-suppressive cultivars with improved allelopathic interference is still a challenge, but traditional breeding or biotechnology should pave the way.     

云南高海拔粳稻区白叶枯病菌致病型的鉴定

水稻白叶枯病是危害水稻的重要细菌性病害之一,病原为稻生黄单胞菌水稻致病变种Xanthomonas oryzae pv.oryzae (Xoo).近10年来云南省水稻白叶枯病的危害向高海拔粳稻区扩散,在海拔2200m的剑川县,白叶枯病已成为最严重的水稻病害[1-2].开展高海拔粳稻区白叶枯病菌致病型的鉴定、分布和分化研究,对云南高海拔粳稻区稻作生产具有指导意义.     

花生除草地膜对田间杂草防除及花生产量的影响研究

通过在广东省花生主产区进行花生除草地膜覆盖栽培试验,探讨了该地膜对不同土壤类型和不同耕作制度的花生田间杂草的防除效果。结果表明:花生除草地膜适用于广东省各花生主产区,且产量平均增加28.93%;花生除草地膜对水旱轮作田和旱地的杂草防除效果略有不同,其中对水旱轮作田杂草的防除效果达80%以上,对旱地杂草的防除效果高达90%以上且防效稳定;在前茬作物为水稻或蔬菜的花生地,花生除草地膜对田间的防除效果均达到80%以上,但要注意控制多年生杂草。     

Multifunctionalised benzoxazinones in the systems Oryza sativa–Echinochloa crus‐galli and Triticum aestivum–Avena fatua as natural‐product‐based herbicide leads

BACKGROUND: Fifteen novel derivatives of D‐DIBOA, including aromatic ring modifications and the addition of side chains in positions C‐2 and N‐4, had previously been synthesised and their phytotoxicity on standard target species (STS) evaluated. This strategy combined steric, electronic, solubility and lipophilicity requirements to achieve the maximum phytotoxic activity. An evaluation of the bioactivity of these compounds on the systems Oryza sativa–Echinochloa crus‐galli and Triticum aestivum–Avena fatua is reported here. RESULTS: All compounds showed inhibition profiles on the two species Echinochloa crus‐galli (L.) Beauv. and Avena fatua L. The most marked effects were caused by 6F‐4Pr‐D‐DIBOA, 6F‐4Val‐D‐DIBOA, 6Cl‐4Pr‐D‐DIBOA and 6Cl‐4Val‐D‐DIBOA. The IC₅₀ values for the systems Echinochloa crus‐galli–Oryza sativa and Avena fatua–Triticum aestivum for all compounds were compared. The compound that showed the greatest selectivity for the system Echinochloa crus‐galli–Oryza sativa was 8Cl‐4Pr‐D‐DIBOA, which was 15 times more selective than the commercial herbicide propanil (Cotanil‐35). With regard to the system Avena fatua–Triticum aestivum, the compounds that showed the highest selectivities were 8Cl‐4Val‐D‐DIBOA and 6F‐4Pr‐D‐DIBOA. The results obtained for 6F‐4Pr‐D‐DIBOA are of great interest because of the high phytotoxicity to Avena fatua (IC₅₀ = 6 µM , r² = 0.9616). CONCLUSION: The in vitro phytotoxicity profiles and selectivities shown by the compounds described here make them candidates for higher‐level studies. 8Cl‐4Pr‐D‐DIBOA for the system Echinochloa crus‐galli‐Oryza sativa and 6F‐4Pr‐D‐DIBOA for Avena fatua‐Triticum aestivum were the most interesting compounds. Copyright © 2010 Society of Chemical Industry     

水稻抗条纹叶枯病鉴定方法的研究

鉴于国内至今尚无水稻条纹叶枯病品种抗性鉴定标准的现状,本文分别研究了接种时间、接种强度与水稻接种苗龄3因素对抗性鉴定的影响。结果表明水稻条纹叶枯病的适合抗性鉴定方法应为：接种时间48～72 h, 接种强度2～6头/株和水稻接种龄期0.5～1.5叶龄。以本研究结果为基础制定了水稻条纹叶枯病品种抗性鉴定的江苏省地方标准。