我国现代农业发展研究

建设现代农业是当今农业和农村工作的主题.介绍现代农业的含义与特点,通过对国内外现代农业发展现状进行对比,阐述我国发展现代农业的必要性,提出我国现代农业发展的有效途径,以实现农业产业化和农村现代化,缩小城乡差别,提高农民收入,改善农民生活.     

农村电网标准化作业管理系统的设计

以C/S和B/S结构为基础,应用UML技术设计农村电网标准化作业管理系统。介绍标准化作业的管理流程,阐述该系统的开发环境、架构和功能,设计了系统用例,并重点介绍作业指导书的设计。经运行实践表明,应用该标准化作业管理系统可实现标准化作业管理的科学化和规范化。     

小麦保护性耕作技术研究与分析

小麦保护性耕作技术是以机械化作业为主要手段,采取少耕或免耕方法,保护土壤、降低生产成本、实现农业可持续发展的机械化耕作技术体系.将保护性耕作技术种植小麦的试验数据与常规耕作技术的试验数据相比较,结果表明:应用保护性耕作技术种植小麦的增温、保墒作用更为明显.麦田含水率较常规耕作的多2.52%,小麦个体发育健壮,平均增产1.6%,节约耕作费用450元/hm2,新增经济效益570元/hm2.     

农村变电站选址规划方法

农村变电站选址是电网规划的重要组成部分,在农网规划是起承上启下的作用,文中介绍最优化选址问题,并将优化选址的数学模型进行分类,又全面地比较分析应用于变电站选址方法的诸多算法,提出5项有利于电力市场环境下的农网变电站选址的建议.     

Immobilization antigen-independent protection of olive flounder (Paralichthys olivaceus) against Philasterides dicentrarchi (Ciliophora: Scuticociliatia) infection

To determine whether olive flounder (Paralichthys olivaceus) immunized with lysate of Philasterides dicentrarchi could be protected immobilization antigen (i-antigen) type independently, fish were immunized with lysate of ciliates obtained from in vitro cultures or ciliates obtained from infected fish. Fish immunized with ciliates obtained from infected fish were completely protected against artificial infection with in vitro cultured P. dicentrarchi, in spite of a weak or no serum agglutination activity against in vitro cultured ciliates. The present results indicate that i-antigen-independent protection was elicited by immunization of fish with the ciliates lysate, and the cultured ciliates would provide a good source for preparation of vaccines, which are cross-protective against various i-antigen types of P. dicentrarchi.     

Application of the rpoS gene for the detection of Vibrio anguillarum in flounder and prawn by polymerase chain reaction

Vibrio anguillarum , an opportunistic fish pathogen, is the main species responsible for vibriosis, a disease that affects feral and farmed fish and shellfish, and causes considerable economic losses in marine aquaculture. In this study, we used polymerase chain reaction (PCR) to detect V. anguillarum . PCR specificity was evaluated by amplifying the rpoS gene, a general stress regulator, in six strains of V. anguillarum and 36 other bacterial species. PCR amplified a species-specific fragment (689 bp) from V. anguillarum . Furthermore, the PCR assay was sensitive enough to detect rpoS expression from 3 pg of genomic DNA , or from six colony-forming units (CFU) mL⁻¹ of cultured V. anguillarum . However, the assay was less sensitive when genomic DNA from the infected flounder and prawn was used (limit of detection, 50 ng and 10 ng g⁻¹ tissue, respectively). These data demonstrate that PCR amplification of the rpoS gene is a sensitive and species-specific method to detect V. anguillarum in practical situations.     

苹果试管苗热处理脱毒法的研究

苹果褪绿叶斑病毒（简称ＣＬＳＶ）、茎沟病毒（简称ＳＧＶ）,是感染苹果的两种重要的潜隐性病毒,在苹果上通常引起慢性衰退症。当用感病材料嫁接时,往往导致衰退病急性暴发,给生产造成毁灭性损失。ＣＬＳＶ和ＳＧＶ均是通过嫁接传染,目前尚无有效的预防和治疗方法,而采用脱毒方法杜绝苗木带毒,把好育苗关,是防治病毒的根本出路。热处理是脱除苹果病毒的主要方法,这在国内已有较多的报道。但直接对试管苗进行热处理脱毒,尚未见报道。本试验系统研究了茎尖培养的试管苗,在光照培养箱内直接进行热处理的方法及优点,并采用酶联免疫…     

Alteration of apoptotic susceptibility and bcl-2 gene in malignant transformation of human bronchial epithelial cells

AIM: To demonstrate the susceptibility of cell apoptosis varies during the progress of cell malignant transformation from human being in vitro. METHODS: A SV₄₀T-transfected human bronchial epithelial immortalized cell line (called M) was selected in this work, which has acquired some characteristics of malignant transformation at the later passage. The alterations of apoptosis and bcl-2, P53 genes between early and later passage of M cells were investigated by means of TDT labeling in situ, chromosome FISH, RNA and protein testing, etc. RESULTS: Incidence of apoptosis induced by cis-platin was significantly lower in later than in early passages of M. Levels of bcl-2 mRNA and protein in later passages were higher than early passages of M, and overexpression of bcl-2 was accumulated following the development of cellular malignancy. P53 protein level was as high in early as in later passages. CONCLUSION: Overexpression of bcl-2 decreases the cellular sensitivity to apoptotic inductors plays an important role during progress of carcinogenesis in human bronchial epithelial cancers. The inactivation of P53 protein in the SV₄₀-T transfected M cell line may be one of reasons of bcl-2 overexpression, but not associated with the accumulation of bcl-2 expressed level during cell transformation.     

Effects of psychological stress on in vitro expression of activated surface molecules on T cells of peripheral blood from healthy persons

AIM: To study cellular and molecular mechanism involved in increasing susceptibility of infection in psychological stress persons. METHODS: Comparative studies were performed with double staining and flow cytometry analysis on immunophenotyping and in vitro expression of early activating surface molecule CD69 in response to mitogens on T cells from peripheral blood of 20 healthy college student volunteers before and after psychological stress. A series of term final examinations was defined as psychological stress. RESULTS: Immunophenotyping analysis showed no statistically significant difference in the percentage of CD2, CD3, CD4, CD8, CD19, CD20, CD16 and CD56 positive lymphocyte populations before and after psychological stress. There was a statistically significant decrease in the in vitro expression of CD69 in response to polyclonal stimulators on the T cells from persons after psychological stress than those before psychological stress. The percentage of CD69 expression (CD69⁺CD3⁺/CD3⁺%) in response to PHA and PDB in the whole blood culture for 72 hours decreased respectively from 28.1±4.1 and 80.7±6.8 on the T cells obtained before psychological stress to 17.6±3.8 and 65.8±7.9 on those obtained after psychological stress, while there was no statistically significant difference between the CD69 expression rates without stimulators on the T cells obtained before and after psychological stress. CONCLUSIONS: The effects of psychological stress to immune system is not on the level of changing proportions of the sub-populations within peripheral blood lymphocytes. Psychological stress can decrease the activating response of T cells in healthy persons, which may be responsible for the increase of susceptibility to infection in the psychological stress persons.     

Effects of glucose and Mg2+ in the neurons damaged by glutamate

AIM and METHODS: To observe the effects of glucose-free and Mg²⁺-free in the extracellular fluid on the changes of [Ca ²⁺]_i in the cerebro-cortical neurons damaged by 1mmol/L glutamate using laser confocal scanning microscope. RESULTS: Both frequency and amplitude of neuronal calcium oscillation induced by glutamate were lowered in glucose-free and Mg²⁺-free buffers. The basic [Ca²⁺]_i concentration was lowered in the former case , but it was elevated in the latter case. CONCLUSION: Mg²⁺-free aggravates [Ca²⁺]_i overload induced by 1mmol/L glutamate ,under certain conditions the glucose-free might resist damage role of glutamate and Mg²⁺-free.