山楂叶螨经济受害水平的研究

1988～1989年,在北京四季青乡11～12年生红星苹果树上,采用人工接螨的方法建立了山楂叶螨雌成螨螨日MD(mite days)级别与苹果2年联合产量损失率Q关系模型。利用此模型建立了雌成螨、雌成螨螨日、活动螨(雌成螨+幼若螨)、有雌成螨叶率时间动态多指标经济受害水平(EIL)模型EIL(Ⅰ)～EIL(Ⅳ)。并应用Croft提出的方法设计了配合该EIL模型的调查取样方法。     

脐带间充质干细胞（HUC-MSCs）质体（Cytoplast）来源CD64过表达纳米囊泡的构建方法研究

目的：人脐带间充质干细胞（HUC-MSCs）来源的纳米颗粒可通过多种载药方式用于药物靶向,是近年来医药领域的研究热点。本文应用过表达CD64(FcγRI)的脐带间充质干细胞（HUC-MSCs）细胞质体（Cytoplast）为原料,制备可装载Ig G1/IgG3靶向抗体的纳米囊泡,并检测纳米囊泡的入胞效率。方法：应用组织块培养法分离HUC-MSCs;建立pLV-CD64慢病毒包装载体并包装慢病毒,用慢病毒感染HUC-MSCs并筛选稳定表达CD64的细胞株;通过细胞松胞菌素B共孵育/离心法去除HUC-MSCs细胞核获得质体;超声法和梯度挤出法制备直径约200 nm的囊泡;将纳米囊泡与抗EGFR的Ig G1抗体共孵育以装载靶向抗体,并观察该纳米囊泡进入A549细胞的入胞效率变化。结果：成功获得稳定表达CD64的HUC-MSCs质体,制备装载EGFR抗体的纳米囊泡（粒径为195±82 nm）并有效提高了该囊泡对靶细胞的入胞效率。结论：成功构建可装载Ig G1抗体的纳米微泡,该纳米囊泡可高效进入表达EGFR的A549靶细胞。     

丹江口水库三种鲤科鱼类寄生木村小棘吻虫的季节动态

作者于2004年2月至2005年2月调查了丹江口水库木村小棘吻虫Micracanthornhynchina motomurai(Harada,1935)感染三种小型经济鲤科鱼类--马口鱼(Opsariichthys uncirostris)、宽鳍(鱼鼠)(Zacco platypus)和油(粲鱼)(Hemiculter bleekeri bleekeri)的季节动态情况.在感染率和感染丰度方面,寄生于马口鱼和油(鱼鼠)的木村小棘吻虫呈现出显著的季节变化:秋冬季节感染率和感染丰度都比较高,而春夏季节比较低;与此不同的是,寄生于宽鳍(鱼鼠)中的木村小棘吻虫则全年都维持着较稳定的感染水平;木村小棘吻虫种群在三种宿主体内的总体感染丰度差异显著,但都呈聚集分布,三者的方均比与感染率和感染丰度之间无显著相关关系.     

A method to test compounds for feeding deterrence towards redlegged earth mite (Acarina: Penthaleidae)

A bioassay, based on a membrane sachet technique, has been developed to identify antifeeding compounds affecting the redlegged earth mite, Halotydeus destructor (Acari: Penthaleidae). The method consists of counting H. destructor numbers on membrane sachets in choice experiments, which was quicker and more efficient than weighing the mites. Five per cent aqueous glucose solution was used as a feeding stimulant, with Tween 80® at 5% concentration as a solubilising agent for water-insoluble compounds. (+)-Catechin, rutin, biochanin A, formononetin, chlorogenic acid, and gramine acted as feeding deterrents at 1% concentration. Quercetin (1 %) and azadirachtin (100 ppm) had no significant effect. At lower concentrations (0.01%), compounds showed antifeeding (gramine), phagostimulating (quercetin and chlorogenic acid), or no effects on mite numbers. Dose-dependent deterrent effects of plant extracts were demonstrated with the bioassay, which could be used for other mites.     

Expression and purification of human (pro)renin receptor in insect cells using baculovirus expression system

The renin-angiotensin (RA) system is important for the regulation of blood pressure and electrolyte balance, and renin is the rate-limiting enzyme in this system. The recent discovery of (pro)renin receptor (PRR) has reinforced the functional role of the RA system. PRR non-proteolytically activates prorenin and its role has attracted the attention of researchers towards the RA system. However, there is insufficient information on the biochemical structure and biological functioning of PRR due to the difficulty of measuring PRR expression. In this work, human PRR (hPRR) with intact transmembrane and C-terminal domain (hPRR-wTM) and PRR without this domain (hPRR-w/oTM) were expressed in insect cells using baculovirus expression system (BES). Both hPRR-wTM and hPRR-w/oTM were fused with FLAG peptide by its N-terminus. Most of the hPRR-wTM was expressed in cell fraction and hPRR-w/oTM was secreted into the culture medium. hPRR-wTM was solubilized from the membrane fraction of recombinant baculovirus-infected cells by various detergents, suggesting that hPRR-wTM might be a transmembrane protein. hPRR-wTM was purified from the solubilized fraction using anti-FLAG M2 antibody agarose. Binding of purified hPRR-wTM to renin immobilized onto sensor chips was directly proportional to the hPRR-wTM concentration. Approximately 225 μg of functional hPRR-wTM was purified from 80 ml of baculovirus-infected cell culture. Scale-up of this system will lead to mass production and crystallization of hPRR-wTM and determination of its biochemical structure and biological function.     

Degradation of maternal poly(A)-containing RNA during early embryogenesis of an insect (Smittia spec., chironomidae,diptera)

Summary Eggs of the chironomid midgeSmittia spec. were shown to contain maternal rRNA, tRNA and poly(A)-containing RNA. The ribonucleoprotein spectrum consisted of monosomes, ribosomal subunits, and subribosomal particles, whereas polysomes could be detected only in small amounts. Poly(A)-containing RNA was found in different regions of the RNP spectrum, mainly between 15 S and 60 S. After labelling maternal RNA by feeding tritiated uridine to the larvae, the radioactivity associated with poly(A)-containing RNA accounted for about 4% of the label in the total RNA extracted from newly deposited eggs. About half of the radioactivity in the poly(A)-containing RNA was lost between egg deposition and an advanced blastoderm stage. The loss was accompanied by both a decrease in the size of the poly(A)-containing RNA molecules and a shift of poly(A)-containing RNP particles to less dense regions in sucrose gradients. Comparison with poly(A)-containing RNA synthesized by the embryo indicates that the reduction in size of maternal poly(A)-containing RNA is not artifactual but reflects its degradation after the formation of blastoderm.     

Transgenic insect-resistant maintainer line (IR68899B) for improvement of hybrid rice

Heterosis has helped to increase rice yield in F₁ hybrids by 15–20% beyond the level of inbred semidwarf varieties. For stable yield performance rice hybrids must also possess genetic resistance to biotic stresses. One of these, stem borer, reduces the expected yield of hybrid rice. The truncated synthetic cryIA(b) gene from Bacillus thuringiensis is known to be effective in controlling stem borer. The development of transformation techniques has provided the technology for incorporating this bacterial gene into the rice genome, which has not been possible by conventional breeding methods. We have introduced a new approach of using a transgenic maintainer line for developing an insect-resistant hybrid rice. An elite IRRI maintainer line (IR68899B) has been transformed with the cryIA(b) gene driven by the 35S constitutive promoter using the biolistic method. The integration and expression of the cryIA(b) gene could be demonstrated through Southern and Western blot analyses that have been carried out so far up to the T₂ generations. Insect bioassay data showed an enhanced resistance to yellow stem borer in the Bt ⁺ transgenic plants. This is the first report of the development of a transgenic maintainer line for use in hybrid rice improvement. Received: 17 December 1997 / Revision received: 23 June 1998 / Accepted: 25 September 1998     

遮荫对新疆紫草育苗的影响

目的 探讨新疆紫草育苗的最佳遮荫条件.方法 采用不同的遮荫条件,研究了遮荫处理对新疆紫草原生苗生长量和成活率的影响.结果 结果表明,不同强度的遮荫处理对原生苗的叶面积、成活率、地下生长量影响显著.适度遮荫可以增加叶面积和地下生长量,提高幼苗成活率,结论 采用30%遮荫率的遮荫处理能够同时满足增加生长量和提高成活率的要求,同时避免了叶片先端的日灼伤害.     

Dose-response time modelling for highly pathogenic avian influenza A (H5N1) virus infection

Aims: To develop time‐dependent dose–response models for highly pathogenic avian influenza A (HPAI) of the H5N1 subtype virus. Methods and Results: A total of four candidate time‐dependent dose–response models were fitted to four survival data sets for animals (mice or ferrets) exposed to graded doses of HPAI H5N1 virus using the maximum‐likelihood estimation. A beta‐Poisson dose–response model with the N₅₀ parameter modified by an exponential‐inverse‐power time dependency or an exponential dose–response model with the k parameter modified by an exponential‐inverse time dependency provided a statistically adequate fit to the observed survival data. Conclusions: We have successfully developed the time‐dependent dose–response models to describe the mortality of animals exposed to an HPAI H5N1 virus. The developed model describes the mortality over time and represents observed experimental responses accurately. Significance and Impact of the Study: This is the first study describing time‐dependent dose–response models for HPAI H5N1 virus. The developed models will be a useful tool for estimating the mortality of HPAI H5N1 virus, which may depend on time postexposure, for the preparation of a future influenza pandemic caused by this lethal virus.     

A method for estimating free Ca within human red blood cells,with an application to the study of their Ca-dependent K permeability

Summary Murphy, Coll, Rich and Williamson (J. Biol. Chem. 255:6600–6608, 1980) described a null-point method for estimating intracellular free Ca in liver cells. They used digitonin to lyse the cells in solutions of varying Ca concentration. This method has been adapted for use with human red cells. The values found are about 0.4 m Ca in fresh cells, and from 0.4 to 0.7 m Ca in blood-bank cells, at pH 7.2 and 37°C. These are likely to be overestimates, and the errors and limitations of the method are discussed. Red cells may be loaded with Ca by metabolic depletion in Ca-containing solutions. Such cells have an elevated K permeability, and the relationships between free Ca, total Ca and K permeability were investigated, using⁸⁶Rb as a tracer for K.⁸⁶Rb flux studies show that the affinity of the K channel for Ca is the same in cells as in resealed ghosts where intracellular Ca can be controlled with Ca buffers, but the rate of tracer equilibration is 3–6 times faster in ghosts than in cells.     

Induction of 2',5' oligo(A) synthetase in tumor-bearing mice with encephalomyocarditis (EMC) virus or poly(I)poly(C)

Infection of 13 month-old C3H mice with EMC virus or inoculation with the interferon inducer poly(I)poly(C) results in elevated levels of the enzyme 2',5' oligo(A) synthetase only in animals with spontaneous tumors (breast cancer or hepatomas). High enzymatic activities are detected in homogenates from liver, spleen, plasma and neoplastic cells of the animals with breast carcinomas and only in the neoplastic liver cells of the animals with hepatomas.     

Detection of mRNA degradation intermediates in tissues using the 3'-end poly(A)-tailing polymerase chain reaction method

It has become increasingly clear that mRNA stability is an important determinant of mRNA abundance in virtually all organisms. Although our understanding of prokaryotic lower eukaryotic mRNA stability mechanisms has progressed considerably, little is known about mammalian mRNA stability mechanisms, particularly at the tissue and animal levels. This is due largely to the lack of suitable methods to approach the problem. In this study, we have developed and refined the 3'-end poly(A)-tailing polymerase chain reaction (PCR) method to detect degradation intermediates in vivo. Using an in vitro transcribed RNA as a template, we found that the method could be used to detect a homogeneous pool of RNA down to 0.1 ng. The addition of 10 microg of total RNA from tissues decreased the sensitivity limit to 4 ng. Detection limits of the technique were determined precisely by varying the concentrations of in vitro transcribed RNA in a constant amount of total RNA and varying the concentration of total RNA while maintaining a constant amount of in vitro transcribed RNA. Our overall results showed that the poly(A)-tailing PCR method could be used to detect specific RNA species of approximately 1000 nt in a pool of heterogeneous RNA in the range of 1 in 2500 to 1 in 10,000. To our knowledge, this is the most sensitive method to date for identifying mRNA degradation intermediates. Employing sense strand gene-specific primers in this method, we have discovered the class II and class III P-glycoprotein (Pgp) mRNA degradation intermediates in normal rat tissues. This method should serve as an additional tool to help us understand mRNA decay mechanisms in tissues and at animal levels.     

一种稻飞虱室内稻芽饲养法

本文介绍了稻飞虱室内稻芽饲养的方法 ,并指出此方法具有操作简便、虫龄整齐、获虫量大、不易引入天敌、可整年饲养等优点 ,比较适合新农药筛选和需要大量试虫进行试验研究的农药研究单位进行饲养