‘Plantibodies’: a flexible approach to design resistance against pathogens

Engineering resistance against various diseases and pests is hampered by the lack of suitable genes. To overcome this problem we started a research program aimed at obtaining resistance by transfecting plants with genes encoding monoclonal antibodies against pathogen specific proteins. The idea is that monoclonal antibodies will inhibit the biological activity of molecules that are essential for the pathogenesis. Potato cyst nematodes are chosen as a model and it is thought that monoclonal antibodies are able to block the function of the saliva proteins of this parasite. These proteins are, among others, responsible for the induction of multinucleate transfer cells upon which the nematode feeds. It is well documented that the ability of antibodies to bind molecules is sufficient to inactivate the function of an antigen and in view of the potential of animals to synthesize antibodies to almost any molecular structure, this strategy should be feasible for a wide range of diseases and pests.Antibodies have several desirable features with regard to protein engineering. The antibody (IgG) is a Y-shaped molecule, in which the domains forming the tips of the arms bind to antigen and those forming the stem are responsible for triggering effector functions (Fc fragments) that eliminate the antigen from the animal. Domains carrying the antigen-binding loops (Fv and Fab fragments) can be used separately from the Fc fragments without loss of affinity. The antigen-binding domains can also be endowed with new properties by fusing them to toxins or enzymes. Antibody engineering is also facilitated by the Polymerase Chain Reaction (PCR). A systematic comparison of the nucleotide sequence of more than 100 antibodies revealed that not only the 3′-ends, but also the 5′-ends of the antibody genes are relatively conserved. We were able to design a small set of primers with restriction sites for forced cloning, which allowed the amplification of genes encoding antibodies specific for the saliva proteins ofGlobodera rostochiensis. Complete heavy and light chain genes as well as single chain Fv fragments (scFv), in which the variable parts of the light (V_L) and heavy chain (V_H) are linked by a peptide, will be transferred to potato plants. A major challenge will be to establish a correct expression of the antibody genes with regard to three dimensional folding, assembly and intracellular location.     

土地资源结构与农林牧合理用地布局的探讨——以甘肃省河西走廊为例

本文以土地资源结构理论为依据,论述了甘肃省河西走廊地区的农业分区,土地资源质量数量结构、农林牧合理用地构成及区域开发的整体布局。     

Preliminary results of using in vitro axillary and adventitious buds in mutation breeding of Chinese gooseberry

Summary Aseptically cultured shoots of Chinese gooseberry exhibited growth disorder and morphological aberrances, and some died after being exposed to sufficient gamma-ray irradiation. The death rate was dose dependant and the LD₅₀ was 80–90 Gy and 50–60 Gy respectively for cv. Hayward and clone 4. All petiole explants irradiated with gamma-ray could form calli as the control, but the rate of differentiation of adventitious shoots of the petiole explants decreased and was dependant on dose. Sensitivity of the shoot or petiole explants to gamma-ray irradiation varied with species. Gamma-ray irradiation did not deter either the 2-node segments from producing axillary shoots M₁, M₂, and M₃ or the advantitious shoots originating in the petiole explants and the M₃ shoots from forming advantitious roots. Therefore, using aseptically cultured axillary or adventitious buds for mutation breeding of Chinese gooseberry is feasible. A bacterium surviving in the explants lessened the efficiency of these two in vitro techniques in mutation breeding of Chinese gooseberry.Abbreviations IAA 3-indole acetic acid - IBA -indole butyric acid - MS Murashige & Skoog (1962)     

自由放养下绵羊的营养参数

根据绵羊的营养参数和饲养标准,结合日增重水平,计算了不同日增重水平对应的体重月平均动态及其所对应的粗蛋白日需要量和代谢能日需要量。不同日增重水平,达到生长期望所需要的日数不同,日增重水平越高,达到生长期望总所需要的粗蛋白和代谢能越少,但月平均的日需要量越多。自由放养的东北细毛羊当年生羔羊的日增重水平仅相当于舍饲饲养日增重的100g水平,根据代谢能计算,年总需干草340kg,可以作为计算载畜量的基本参数。自由放养情况下,即使能量满足需要,粗蛋白也短缺。当年生羔羊日增重在150￣200g,9￣10月龄内体重达到46￣50kg是北方草地家畜生产的理想目标,通过补饲可以实现。     

Ovipositor length of threeApocrypta species: Effect on oviposition behavior and correlation with syconial thickness

We investigated oviposition behavior in three non-pollinating fig wasps: the sympatric speciesApocrypta bakeri Joseph onFicus hispida L.,A. westwoodi Grandi onF. racemosa L., andApocrypta sp. onF. semicordata Buch.-Ham. The oviposition behavior differs significantly between one pair of species (A. bakeri andA. westwoodi) and the other species (Apocrypta sp. onF. semicordata).A. bakeri andA. westwoodi were similar in the following aspects: the posture of the abdomen and the action of the hind legs before penetration, and the bending ovipositor sheath during penetration. In contrast, the oviposition behavior ofApocrypta sp. is quite different. This difference can be explained by the significant correlation between ovipositor length and syconial thickness.Apocrypta sp. has a shorter ovipositor than the two other species, which correlates with the thinner syconial wall of its host figF. semicordata. It is deduced that the ovipositor length adapts to the syconial thickness and induces the oviposition behavior in the different species to diverge. For all threeApocrypta species, the midleg length and hindleg length are significantly correlated with their ovipositor lengths. This may be explained as due to the fact that body movement adjusting the hindlegs and midlegs up and down, or forward and backward, is also influenced by the ovipositor length.     

板栗优良新品种‘黄棚’

 ‘黄棚’是20世纪90年代初从海拔300 m以上的山地栗园选出的实生变异优株。经多年高接鉴定和丰产栽培试验表明, 该品种早实, 丰产, 抗旱, 耐瘠薄, 品质优良, 为中早熟、适应范围广的炒食型板栗新品种。     

利用DTOPSIS法综合评价番茄新品种

以苏州地区2004年番茄区域试验数据为资料,利用DTOPSIS法进行综合分析,初步探讨了该统计方法在番茄新品种评价应用中的有关问题。结果表明,利用DTOPSIS法进行分析的结果与区域试验常规分析的结果基本一致,且比单用产量分析更为合理。     

万寿菊的研究进展

本文概述了万寿菊的主要品种、形态特征、生物学特性、香气组成成分、功能用途、栽培管理方式及育种等内容，并对万寿菊的发展前景作了展望．     

积极引导加强服务加快饲料行业质量认证步伐

同志们: 这次饲料行业危害分析与关键点控制(HACCP)安全管理体系及产品认证试点工作座谈会的主要任务是,深入贯彻中央一号文件,全面落实科学发展观,认真总结2004年以来全国饲料行业开展HACCP安全管理体系及产品认证试点工作,分析存在的问题,明确认证工作的思路,加快认证步伐,提高饲料行业质量管理水平.下面,我就HACCP安全管理体系及产品认证工作讲三方面的意见.     

哺乳犊牛的消化特点与蛋白质需要

本文从犊牛的消化生理特点出发,综述了犊牛出生后的生理特征及蛋白质、必需氨基酸的需要量,并对代乳品中蛋白质原料进行了论述。