5种生物杀虫剂对4种天敌昆虫的安全性评价

【目的】生物杀虫剂及天敌昆虫的应用是绿色防控的发展方向,但有关生物杀虫剂对天敌昆虫的安全性尚不明确。研究生物杀虫剂对天敌昆虫的影响可以为更好地协调使用生物杀虫剂和天敌昆虫提供理论依据。【方法】在实验室条件下采用药膜法和滤纸膜片法测定了5种生物杀虫剂(苦参碱、桉油精、鱼藤酮、除虫菊素、橄榄鲨)在田间推荐使用浓度下,对4种天敌昆虫(丽蚜小蜂、东亚小花蝽、食蚜瘿蚊、巴氏新小绥螨)的致死率。【结果】除虫菊素对丽蚜小蜂、东亚小花蝽、巴氏新小绥螨的影响较大,致死率均达到100%;鱼藤酮对丽蚜小蜂、食蚜瘿蚊、巴氏新小绥螨的影响均较大,致死率在98.65%以上;橄榄鲨对丽蚜小蜂、东亚小花蝽、食蚜瘿蚊的影响较小,致死率均小于30%;苦参碱对丽蚜小蜂的影响最大,致死率达100%,对食蚜瘿蚊和巴氏新小绥螨的影响较小,致死率分别为15.56%和15.91%;桉油精对巴氏新小绥螨的影响最大,致死率达100%,对东亚小花蝽和食蚜瘿蚊的影响较小,致死率分别为15.91%和6.67%。【结论】这5种生物杀虫剂中,橄榄鲨对丽蚜小蜂、东亚小花蝽、食蚜瘿蚊安全,桉油精对东亚小花蝽、食蚜瘿蚊安全,苦参碱对食蚜瘿蚊、巴氏新小绥螨安全,鱼藤酮对东亚小花蝽安全,除虫菊素对食蚜瘿蚊安全。     

干旱胁迫下冠菌素对玉米幼苗光合参数和内源激素含量的影响

采用沙培称重法研究冠菌素对玉米幼苗光合参数及内源激素系统影响的结果表明,干旱胁迫下,0.01μmol·L-1冠菌素显著增加玉米幼苗茎基部粗、根长、干鲜重、光合速率、蒸腾速率和气孔导度,降低胞间二氧化碳浓度,提高幼苗的ABA和1-氨基环丙烷-1-羧酸(ACC)含量。叶片与根中ABA/GA3大时耐旱性增大。     

Global investigation of the co‐evolution of MIRNA genes and microRNA targets during soybean domestication

Although the selection of coding genes during plant domestication has been well studied, the evolution of MIRNA genes (MIRs) and the interaction between microRNAs (miRNAs) and their targets in this process are poorly understood. Here, we present a genome‐wide survey of the selection of MIRs and miRNA targets during soybean domestication and improvement. Our results suggest that, overall, MIRs have higher evolutionary rates than miRNA targets. Nonetheless, they do demonstrate certain similar evolutionary patterns during soybean domestication: MIRs and miRNA targets with high expression and duplication status, and with greater numbers of partners, exhibit lower nucleotide divergence than their counterparts without these characteristics, suggesting that expression level, duplication status, and miRNA–target interaction are essential for evolution of MIRs and miRNA targets. Further investigation revealed that miRNA–target pairs that are subjected to strong purifying selection have greater similarities than those that exhibited genetic diversity. Moreover, mediated by domestication and improvement, the similarities of a large number of miRNA–target pairs in cultivated soybean populations were increased compared to those in wild soybeans, whereas a small number of miRNA–target pairs exhibited decreased similarity, which may be associated with the adoption of particular domestication traits. Taken together, our results shed light on the co‐evolution of MIRs and miRNA targets during soybean domestication.     

精子介导GFP基因在小鼠早期胚胎中的表达

利用 DIG 末端标记技术和免疫组化技术分析了小鼠精子体外结合内化外源DNA的效率。试验结果表明,不同小鼠个体的精子结合外源DNA的阳性率有明显差异（P<0.01）,平均为13%。利用考马斯亮蓝染色评价了小鼠精子顶体反应发生的情况,筛选出TYH培养液为较合适的体外受精液。利用小鼠体外受精技术,将体外转染GFP基因并获能的小鼠精子与成熟卵母细胞进行体外受精,受精卵进行体外培养,表达GFP胎的阳性率为4.7%。验证了精子介导制备转基因小鼠胚胎的可行性,并建立了利用精子载体法制备转基因小鼠胚胎的平台。     

Asymmetric Somatic Hybridization Between Wheat (Triticum aestivum) and Bromus inermis

Asymmetric hybridization was conducted between wheat and Brorrats inermis keyss which is a distanfiy related intergeneric plant (belonging to different tribe) of wheat and possesses some favorable traits, such as resistant to cold, drought and disease. Protoplasts isolated from young embryo-derived calli of common wheat ( Triticura aestivum L., tv. 99P, (AABBDD), 2n = 42) were fused with UV-treated protoplasts isolated from young embryo-derived calli of Bromus inermis by PEG method. Three clones (No. 1 ~ No. 3) were regenerated from the fusion products and differentiated into albino seedlings. The clones and the seedlings were all verified as hybrids by chromosome counting, isozyme and RAPD analysis. Their isozyme and RAPD pattern contained the characteristic bands of both parents as well as new band(s). The chromosome numbers of albino were in the range of 42~54 with small chromosomes of Bromus inerm/s and chromosome fragments. The above results confirmed that hybrid albinos were obtained.     

Assembly characteristics of plant keratin intermediate filaments in vitro

After selective extraction and purification, plant keratin intermediate filaments were reassembled in vitro. Scanning tunneling microscope (STM) and transmission electron microscope (TEM) micrographs showed that acidic keratins and basic keratins can assemble into dimers and further into 10 nm filaments in vitro. In higher magnification images, it can be seen that fully assembled plant keratin intermediate filaments consist of several thinner filaments of 3 nm in diameter, which indicates the formation of protofilaments in the assembly processes. One of the explicit features of plant keratin intermediate filaments is a 24—25 nm periodic structural repeat alone the axis of beth the 10 nm filaments and protofilaments. The periodic repeat is one of the fundamental characteristic of all intermediate filaments, and demonstrates the half staggered arrangement of keratin molecules within the filaments.     

Composition and structure of nucleolar skeleton (nucleolar matrix)——Actin and fibrillarin are two main protein components of nucleolar skeleton

Purified nucleoli of HeLa cells were treated sequentially with nonionic detergent, nucleic acid enzyme, low salt and high salt. The residual nucleolar structure termed nucleolar skeleton (nucleolar matrix) was shown as a fine network under electron microscope with DGD embedding-unembedding technique. Such structures of BHK-21 cell and mouse liver cell are similar to that of HeLa cell. The protein composition of the nucleolar skeleton of HeLa cells was analyzed. The protein composition of such nucleolar residual shows obvious difference from the compositions of nuclear matrix and chromosome scaffold. The major protein composition of the nucleolar skeleton of HeLa cells contains 6-7 polypeptides. Their molecular weights are about 48, 43, 36 and 33 ku. Further studies show that actin and fib-rillarin are two major protein components of nucleolar skeleton of HeLa cells.     

水稻抗白叶枯病基因Xa-4的PCR标记研究

根据与水稻抗白叶枯病基因Xa-4紧密连锁的分子标记M55的序列设计引物,通过对国际水稻研究所育成的抗白叶枯病近等基因系和基因累加系的叶片DNA、半粒种子提取物及Xa-4基因的杂合体DNA的PCR特异扩增,初步建立了Xa-4的PCR标记体系。进而用该标记体系对我国籼型杂交水稻常用的亲本材料进行分析,揭示出了Xa-4在这些材料中的分布情况。 Abstract　Based on the sequence of a DNA marker tightly linked to the rice bacterial blight（BB） resistance gene Xa-4, two primers were designated and synthesized to develop a PCR marker for the gene. Specific amplified polymorphism analysis was carried out with these primers on a set of BB resistance isogenic lines and pyramided lines developed by IRRI. Two PCR bands were revealed corresponding to lines with dominant Xa-4 and those with the recessive allele, respectively, regardless the lines pyramided with other resistance genes. A hybrid with heterozygous Xa-4 produced both of the two allele PCR pattern. Then, the PCR marker was used to survey a range of hybrid rice germplasm. The results of the germplasm survey will be useful in hybrid rice breeding programs aimed at exploiting Xa-4.