Structural and ultrastructural alterations of Malpighian tubules of Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) larvae infected with different Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) recombinant viruses

Malpighian tubules constitute the main excretion organ of insects. Infection by egt⁻ recombinant AcMNPV baculovirus in lepidopteran larvae promotes early degeneration of these structures, which has been correlated with earlier death of the host. However, no trace of viral infection has been detected in that tissue. We constructed two AgMNPV recombinants with the egfp gene under control of the hsp70 promoter, one being egt⁻, and used another two recombinants (one egt⁻) containing the lacZ gene. Morphological alterations in the tubules were analyzed by light and electron microscopies. Bioassays were conducted to compare the pathogenicity of recombinants. Results showed progressive presence of marker proteins and tissue degeneration without signals of infection in the tissue. Morphological and bioassay results showed increased pathogenicity for lacZ-containing recombinants compared to the egfp ones; as for egt⁻ viruses, we noted higher intensity and earlier onset of alterations. The absence of infection led us to believe that Malpighian tubules degeneration is provoked initially by the death of tracheal cells attached to the tubules and later, by the death of Malpighian tubule cells themselves. Tubule cell death might be due to oncosis and apoptosis, which may be activated by depletion of energy reserves and by accumulation of marker proteins, respectively. Absence of the egt gene may be leading to a higher energetic expense due to molting, thus aggravating tubule cell death, resulting in faster death of host.     

H5N1 influenza marker vaccine for serological differentiation between vaccinated and infected chickens

Using plasmid-based reverse genetics, we generated a molecularly altered virus, H5N1/PR8-5B19, containing modified HA and NA genes from A/Goose/Guangdong/1/96 (GS/GD/1/96). In the H5N1/PR8-5B19 virus, the HA cleavage site was modified to resemble that of low-pathogenic avian strains and a portion of the NA stalk region was replaced by the immunodominant 5B19 epitope of the S2 glycoprotein of murine hepatitis virus (MHV). H5N1/PR8-5B19 is not lethal to embryonated eggs or chickens. Chickens immunized with the H5N1/PR8-5B19 inactivated vaccine produced high levels of HI antibody and a measurable antibody response against the MHV 5B19 epitope, and were fully protected against subsequent challenge with different highly pathogenic H5N1 avian influenza viruses. H5N1/PR8-5B19 is therefore an attractive marker vaccine candidate, eliciting a strong, protective antibody response and enabling serological discrimination between vaccinated and wild-type virus-infected chickens.     

海南主要普通野生稻的调查及利用RAPD技术进行鉴别分析

通过对海南现存的主要普通野生稻资源进行考察,报道了海南主要普通野生稻的最新生存状况;并用RAPD技术对其进行分析。从供试材料中筛选出具有多态性的RAPD引物13条,共扩增出155条带,其中多态性条带120条,多态性条带比率(PPB)值为77.42%。UPGMA聚类结果表明:海南主要普通野生稻之间遗传关系较复杂、差异较明显,并将海南主要普通野生稻资源划分为5个小类群,可以很好地将海南本地野生稻与收集保存的野生稻鉴别开来,为海南普通野生稻资源的合理利用与有效保护提供了重要依据。     

作物抗旱相关分子标记及其辅助选择的研究进展

分子标记辅助选择育种给作物抗旱育种提供了新的途径。本介绍了国内外在小麦、玉米、水稻、大豆等重要农作物抗旱相关分子标记方面的研究进展。对作物抗旱相关QTL分子标记辅助育种进行了探讨,并对其发展策略提出了一些思考。     

Prediction of sample size to maintain genetic variation in doubled-haploid populations following marker selection

Marker selection (MS) and doubled-haploid (DH) technologies have the potential to reduce the time taken to breed new cereal cultivars. However, a limiting factor is the potential increased genetic drift. The aim of this study was to design and test a genetic model for predicting the sample sizes needed to maintain genetic variation among DH plants following marker selection. The model estimates the amount of the genome that is fixed during the production of DH populations of a given size using a given number of markers. To test the model, doubled-haploids were produced from wheat plants selected for three PCR-based markers. When the genetic variation of the DH population (108 plants), produced from 15 selected F₂ plants homozygous at three loci, was compared to the genetic variation of an unselected F₃ population (200 plants), five of the six measured quantitative traits were identical and normally distributed. This model should prove to be a valid breeding tool, allowing a breeder to apply MS to a breeding programme and estimate the minimum DH population sizes required for minimal loss of genetic variation through genetic drift. Received: 16 October 2000 / Accepted: 20 March 2001     

The chemotaxonomic classification of Korean Campanulaceae based on triterpene,sterol, and polyacetylene contents

The taxonomic usefulness of selected marker compounds was investigated by analyzing the chemotaxonomy of 25 taxa in the Korean Campanulaceae. Our data permit discrimination of the source plants of crude drugs listed in the Korean Pharmacopoeia and the Korean Herbal Pharmacopoeia. Chemotaxonomic analysis methods were validated, and quantitative measurements of six marker compounds were made using HPLC. Marker compound similarities among taxa were identified through multivariate statistical analyses (principal component analysis and hierarchical cluster analysis). The chemical analysis method was validated with regard to linearity, lower limit of detection, lower limit of quantitation, precision, accuracy, and recovery. The analysis revealed differences in the marker compound composition of each genus. Eight genera comprising Adenophora, Codonopsis, Asyneuma, Campanula, Hanabusaya, Platycodon, Wahlenbergia, and Peracarpa clustered according to the chemical classification. The results indicated that the six marker compounds used in this analysis were useful in identifying Korean Campanulaceae. These marker compound data were able to successfully discriminate among the three species that are sold as the crude drug Adenophorae Radix.     

分子标记辅助选择改良水稻不育系臻达A及其杂交种的稻瘟病抗性

水稻抗稻瘟病基因Pi25是一个遗传传递能力强的广谱抗性基因。本研究以携带抗稻瘟病基因Pi25的BL27为抗源供体,与优质、配合力强、感稻瘟病的水稻保持系臻达B为受体亲本进行杂交、回交创制水稻抗病保持系新种质,再与臻达A测交和回交进行不育系转育,结合分子标记辅助选择和农艺性状筛选,获得3个抗性基因纯合、农艺性状和开花习性均与臻达A相似的改良不育系株系。利用福建省近年来致病性代表的22个稻瘟病菌株对3个改良不育系及其15个杂交种进行抗性鉴定,3个改良不育系的抗性频率为95.45%~100%,15个杂交种的抗性频率均达75%以上,而原始对照臻达A及其杂交种的抗性频率仅为54.55%和40.91%~63.64%。自然病圃诱发鉴定表明,3个改良不育系的叶瘟和穗颈瘟均为0级,表现高抗,而对照臻达A的叶瘟为5级,穗颈瘟为7级,表现感病;15个杂交种均表现良好的稻瘟病抗性。进一步分析比较15个杂交种的产量、农艺性状和稻米品质表现,结果表明臻达A-Pi25-3改良不育系的综合性状表现最优,继续回交转育,于2015年育成了稻瘟病抗性强、配合力好、群体整齐和性状稳定的不育系,命名为157A。研究表明,抗稻瘟病基因Pi25不仅在水稻不育系臻达A的遗传背景下的抗性表达完全,且在不同水稻恢复系测交种的背景下同样表现出较高水平的抗性,说明抗性基因Pi25对不育系稻瘟病改良的效果明显。创制的新不育系157A的稻瘟病抗性显著提高,还基本保留了原来不育系高配合力等优良特性,为选育高产、优质、抗病杂交稻新品种提供了不育系新种质。     

珊瑚和海葵来源红荧光蛋白的研究和应用

绿色荧光蛋白作为标记蛋白和报告蛋白在生物学研究中应用越来越广。但在荧光共振能量转移(fluorescenceresonanceenergytransfer,FRET)等技术中存在一些缺陷,需要更大波长范围的荧光蛋白。最近研究发现了多种来源于珊瑚和海葵的红荧光蛋白,这些长波长的荧光蛋白对绿色荧光蛋白是一种很好的代替和补充,可以实现细胞内多荧光标记,提供更理想的FRET荧光对。经随机突变和定点突变等方法改建获得的红荧光蛋白变种显示出更高的荧光强度,成熟时间也更短。目前应用较多的是来源于香菇珊瑚(Discosomasp.)的红荧光蛋白DsRed。     

Efficacy of bacteriophage Lysed Pasteurella marker vaccine in laboratory animal models with a novel DIVA for haemorrhagic septicaemia

Objective

The present study aimed at evaluating the efficacy of an improved phage lysate marker vaccine for haemorrhagic septicaemia in mice and rabbit model and development of a DIVA ELISA based on iron restricted outer membrane protein (IROMP).