专家系统在植保上的应用

专家系统在植保上主要应用于病虫害诊断、预测预报、决策管理等领域。植保专家的特点是应用范围广、实用性增强、新技术和新方法不断应用、有向综合性系统发展的趋势。文中还对植保专家系统存在的问题和发展对策进行了讨论。     

以Taichung29为背景的小麦抗条锈病近等基因系转育进展

自1988年起,系统开展了以Taichung29为背景的小麦抗条锈病近等基因系转育及其基础性研究。采用回交法和系谱法相结合的转育方法,以春性品种Taichung29为轮回亲本作母本,分别与25个抗性供体即中国小麦条锈病菌鉴别寄主和国际上重要的抗条锈基因载体品种杂交、回交和自交。通过基因推导分析、单体分析和SSR标记技术检测目的基因,选育抗条锈近等基因系,现已获得重要进展,成功选育出8个以Taichung29为背景的抗条锈病单基因近等基因系,即Taichung29*6／Yr1、Taichung29*6／Yr2、Taichung29*6／Yr5、Taichung29*6／Yr7、Taichung29*6/Yr9、Taichung29*6／Yr10、Taichung29*6/YrSpP、Taichung29*6/YrKy2。另有9个组合转育获得343个抗性稳定株系,正检测其目的基因,3个组合转至BC₆F₃,自交纯合筛选抗性稳定株系,5个组合转至BC₅,继续回交转育。     

Effect of EGFP gene transfection on the cell cycle distribution of primary cultured human chondrocytes

AIM: To investigate the effect of enhanced green fluorescence protein (EGFP) gene transfection on the cell cycle distribution of primary cultured human chondrocytes in order to establish a tracking method of cultured human nasoseptal chondrocytes. METHODS: pEGFP-N1 plasmid was amplified in E.coli, and purified by high purity kit. Primary cultured human chondrocytes,which were initially obtained from the nasoseptal cartilage, were cultured in vitro and transferred with pEGFP-N1 by means of electroporation with Amaxa nucleofector device. Transfering process and transient expression were evaluated by laser scanning confocal microscope (LSCM), the transfer efficiency and the cell cycle distribution were evaluated by flow cytometry. RESULTS: There was significant expression of EGFP at 24 h after transferring. The transfection efficiency of pEGFP-N1 into primary cultured human chondrocytes reached 35.37％ at 48 h. It didn't affect the process of cell adherance and had no effect on the cell cycle distribution. CONCLUSION: Primary cultured human chondrocytes, which were transfected with pEGFP, are alive in vitro, and the transferring process doesn't affect the cell cycle distribution. These results suggest that pEGFP-N1 is an ideal transient expression vector for primary cultured human chondrocytes and it might be a well tracer in construction tissue engineered cartilage.     

Taurine reduced oxygen free radical production induced by homocysteine in electron transport chain and homocysteine inhibites taurine transporter in mitochondria membrane

AIM: To observe effects of homocysteine and antagonized effects of taurine on electronic leakage and free radical production in myocardial mitochondria. METHODS: Myocardial mitochondria of rat heart was isolated, and was broken by supersonic wave to prepare submitochondria. Recombinant of succinic acid cytochrome c reductase was prepared with mitochondria of porcine heart. They were co-incubated with homocysteine and/or taurine with various concentration. The H₂O₂ and O₂^- were determined by chemiluminescence methods. The taurine transporter of heart mitochondria and its propert, and effects of homocysteine on its function were studied with glass filter. RESULTS: Homocysteine stimulated oxygen free radical production in heart mitochondria, submitochondria, and succinic acid cytochrome c in a concentration-dependent manner. Although taurine itself did not affect oxygen free radical production, taurine did inhibit oxygen free radical production in mitochondria, submitochondria and succinic acid cytochrome c in a concentration-dependent manner. Taurine transporters of Na⁺-dependent were existed in mitochondria membrane. Homocysteine inhibited taurine transtport in mitochondria in a concentration-dependent manner. CONCLUSIONS: Taurine inhibited electronic leakage and oxygen free radical production induced by homocysteine in electron transport chain. There were taurine transporters in mitochondria membrane, and transport functions of taurine transporter were inhibited by homocysteine.     

Induction of tumor-specific cytotoxic T lymphocytes in vitro by dendritic cells pulsed with different glioma antigens

AIM: The goal of this study was to compare different methods for tumor antigen preparation, to observe the induction of tumor-specific cytotoxic T lymphocytes in rats by dendritic cells (DCs) pulsed with different tumor antigens. METHODS: The precursors of dendritic cells were isolated from bone marrow of rats, stimulated in vitro with recombinent rat granulocyte-macrophage colony-stimulating factor (rrGM-CSF) and interleukin-4 (rrIL-4). Then rat DCs were pulsed with C6 tumor cell antigens prepared with different methods: freeze-thaw, boiling or total protein extracted from ultrasonic crushed tumor cell. Subsequently primed DCs were cocultured with T lymphocytes isolated from spleen to induce CTL. Lymphocyte chemoattractant factor from DCs and cytokine IFN-γ release were determined by ELISA, the cytotoxicity of CTL was assayed by JAM test. RESULTS: DCs pulsed with boiled tumor cell in vitro induced an enhanced ability of T-cell proliferation and cytotoxic T lymphocyte activity.CONCLUSION: Our results demonstrated that DCs primed with boiled tumor cell may represent a method for inducing immune responses against the entire repertoire of tumor antigens of malignancies.     

Effects of Sini decoction on the ultrastructure of small intestinal epithelial cells in rats with intestinal ischemia-reperfusion

AIM: To investigate the effect of Sini decoction (SND)on the ultrastructure of small intestinal epithelial cells in rats with intestinal ischemia-reperfusion. METHODS: Thirty-two Sprague-Dawley rats of both sexes were randomly divided into 4 groups: (1) Control group in which sham operation was performed; (2) Model group in which intestinal I/R was produced by clamping super mesenteric artery(SMA) for 1 hour and declamping SMA for 3 hours; (3) SND1 group in which SD (0.6 g/200 g rat) was given via stomach tube 3 d before intestinal I/R; (4) SND2 group in which SD (1.2 g/200 g rat)was given via stomach tube 3 d before intestinal I/R. A strip of small intestine was taken from distal end of ileum for electron microscopic examination. The two-dimensional structural parameters and three-dimensional structural parameters of mitochondria were calculated. RESULTS: (1)Morphological changes of small intestine: In control group, epithelial cells were orderly arranged, with normal mitochondria and intestinal villi. In model group, the gaps between epithelial cells widened. There were a lot of apoptotic cells. Microvilli were short and swelled. Mitochondria were swelled obviously with broken ridges. Endoplasmatic reticulum was severely dilated. In SND1 and SND2 groups, microvilli and epithelial cells were orderly arranged relatively, mitochondria was slightly swelled. (2) Structural parameters of mitochondria: In model group, there were the least mitochondria and the swelling of mitochondria was severe. In SND1 and SND2 groups, the mitochondria was more than that of model group and the swelling were slight. CONCLUSION: Sini decoction can protect small intestine from ischemia-reperfusion injury without dose-dependent effect.     

Effects of non-excitatory electric stimulation on cardiac function in normal and infarcted heart rabbits and it's regional effect on myocardium

AIM: To investigate the influences of electric stimulation applied during the absolute refractory period (ARP) on the cardiac function of normal rabbits and rabbits after myocardial infarction (MI) and to observe the regional effects of this electric stimulation. METHODS: 64 rabbits were randomly assigned to normal and MI groups and each group was then divided into the anterior and posterior groups. A thoracotomy was performed 4 weeks after MI in rabbits. One set of electrodes was inserted into the anterior and posterior wall of left ventricle of the anterior and posterior groups, respectively. Current pulses were delivered during the ARP (called CCM) during sinus rhythm in rabbits. The left ventricular systolic pressure (LVSP) and the left ventricular end diastolic pressure(LVEDP) as well as maximum positive and negative left ventricular pressure change (±dp/dt_max) were observed. RESULTS: In the normal and MI groups, LVSP, +dp/dt_max significantly increased, and LVEDP, -dp/dt_max were reduced during CCM stimulation compared with the baseline (P<0.05). In the normal rabbits, electric stimulation in the anterior group improved the cardiac function more significantly than that in the posterior group (P<0.05). In the MI rabbits, there was no difference between the anterior and the posterior groups (P>0.05). CONCLUSION: Electric stimulation delivered during the ARP significantly enhances the contractility and the relaxation of myocardium in normal rabbits and rabbits after MI, and the effects of CCM stimulation on heart are regional.     

Effects of inhibition of Kupffer cell and splenectomy on thioacetamide-induced hepatic injury

AIM: To examine the effects of inhibition of Kupffer cell and splenectomy on intestinal endotoxemia and hepatic injury. METHODS: The hepatic injury model was established by treatment with thioacetamide (TAA). At the same time, inhibition of Kupffer cells by intravenous GdCl₃ and splenectomy were performed. Serum alanine aminotransferase (ALT), TNF-α, endotoxin content and phagocytic index were observed. RESULTS: In the TAA+GdCl₃ group, and TAA+splenectomy group, the endotoxin content was significently higher than that in normal and TAA group (P<0.05). The plasma TNF-α, ALT and total bilirubin were significantly lower than those in TAA group (P<0.05). CONCLUSION: Inhibition of Kupffer cells and splenectomy increase plasma endotoxin level, but decreases the plasma TNF-α levels and alleviates the hepatic injury induced by TAA.     

中国苜蓿育成品种遗传多样性及亲缘关系研究

以苜蓿的种子贮藏蛋白的多态性为研究指标,对中国14个审定登记的苜蓿育成品种的遗传多样性及亲缘关系进行了研究。研究结果表明:蛋白单体的分子量介于21.2～85.1kD之间,蛋白单体电泳图谱多态性品种间无显著的特异性;在参试的14个育成品种中,品种内基因多样性平均值(HS)为0.3136,总基因多样度(HT)为0.3741,基因分化系数(GST)为0.162;以λ=3.700为标准划分,14个育成品种划分为六个组群,各组群划分结果主要与参试品种的亲本来源有关,而与其种植地、育种地关系不大。     

新型除草剂防除狼毒效果研究

应用中国科学院寒旱所研制的新型除草剂———43.2%'灭狼毒'超低容量制剂在狼毒盛花期采用1.05l/hm2的施药量叶面喷雾,可使受药狼毒的死亡率达到95%以上,死亡狼毒植株次年返青率不足1%,而且能有效抑制草地狼毒群落,促进禾本科牧草生长,对草地可食牧草和非靶标生物安全。