Short-term storage and cryopreservation of Urechis unicinctus (Echiura: Urechidae) sperm

In the present study, attempts were made to preserve Urechis unicinctus sperm at 4°C. Cryopreservation procedures were optimized for various cryoprotectants and freezing rates, equilibration times and dilution ratios. During short‐term storage, the motility of undiluted sperm was extended for 6 days of cold storage,and in 70% and 100% artificial seawater only persisted for 2 and 4 days respectively. The survival rate of undiluted sperm was maintained at a high level accordingly. After cryopreservation, the highest motility and survival rate (41.5±2.2%) were obtained in 15% dimethyl sulphoxide (Me₂SO) using a freezing rate of 30°C min^?1. After thawing the sperm cryopreserved in glycerol lost almost all motility. The motility and survival rate of post‐thawing sperm did not show significant differences after 8 and 15 min equilibration using 15% Me₂SO as cryoprotectant; the values were significantly higher than those of 2 min equilibration. Comparisons of motility and survival rate between treatments pooled by dilution ratio showed that the effect of 1:1 ratio (sperm volume to cryoprotectant volume) was best. There was no difference between 1:3 and 1:5, and other ratioswere significantly worse.     

Using a combination of SAR element and enhancer to increase the expression level of hybrid genes in transgenic animals

A regulatory element consisting of a MAR element sequence of Drosophila heat shock genes and enhancer from a long terminal repeat of the mouse mammary tumor virus is created for studying the possibility of increasing the expression level of hybrid genes in transgenic animals. Two lines of transgenic mice containing the described regulatory element and hybrid gene intended for expressing human beta interferon in milk of transgenic animals are obtained by the method of coinjection into the pronuclei of murine zygotes. It is shown that the use of the given regulatory element doesn’t lead to an increase of activity of human beta interferon in milk compared with transgenic rabbits containing only the hybrid gene for expressing beta interferon. Furthermore, a decrease of tissue-specific expression of beta interferon is observed with the use of the regulatory element.     

Fluorescence polarization immunoassay based on a monoclonal antibody for the detection of the organophosphorus pesticide parathion-methyl

A fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody for the detection of parathion-methyl (PM) was developed and optimized. Fluorescein-labeled PM derivatives (tracers) with different structures were synthesized and purified by thin-layer chromatography. The influence of immunogen and tracer structures on the assay characteristics was investigated. PM concentration determinable by the FPIA ranged from 25 to 10000 ppb. The detection limit was 15 ppb. Methanol extracts of vegetable, fruit, and soil samples were diluted 1/10 for the analysis. Recovery in spiked samples averaged between 85 and 110%. The method developed is characterized by high specificity and reproducibility (CV ranged from 1.5 to 9.1% for interassay and from 1.8 to 14.1% for intra-assay). The FPIA method can be applied to the screening of food and environmental samples for PM residues without complicated cleanup.     

Barley Stripe Mosaic Virus (<Emphasis Type="Italic">Virgaviridae,Hordeivirus</Emphasis>) As Etiological Agent of Maize Chlorotic Stripe Disease

The presence of barley stripe mosaic virus (BSMV) (Virgaviridae, Hordeivirus) infection background in maize (Zea mays) crops in the territory of Primorsky krai was demonstrated. Field data and model experiments established that BSMV causes the disease formerly called “maize chlorotic stripe disease” with the following symptoms: general chlorosis of leaves at the early stages of plant development, the emergence of pale yellow, nearly white strikes along the midrib throughout the length of the leaf, and loss of infected plants to the stage of pulling (12–25%; average value of 17.1%) and elongation with the absence of severe death in the later stages. The coefficient of harmfulness for BSMV (37.1%) was determined in the study. We concluded that planned monitoring in relation to BSMV is required for planting maize.     

Use of LOD score technology in mapping quantitative trait loci in plants

The use of LOD score analysis developed on the basis of the maximum likelihood method for establishing genetic linkage between loci determining the manifestation of quantitative traits and molecular markers in plant genetics is examined. Experimental data on the use of this approach for revealing LOD values in higher plants for the example of mapping Brassica rapa L. populations are given.     

Probing gene expression in live cells, one protein molecule at a time

We directly observed real-time production of single protein molecules in individual Escherichia coli cells. A fusion protein of a fast-maturing yellow fluorescent protein (YFP) and a membrane-targeting peptide was expressed under a repressed condition. The membrane-localized YFP can be detected with single-molecule sensitivity. We found that the protein molecules are produced in bursts, with each burst originating from a stochastically transcribed single messenger RNA molecule, and that protein copy numbers in the bursts follow a geometric distribution. The quantitative study of low-level gene expression demonstrates the potential of single-molecule experiments in elucidating the workings of fundamental biological processes in living cells.     

北京鸭(Anas Domestica L.)舌部的肌肉和神经

本文解剖了北京鸭头15例,两侧共30面。观察了舌骨的构造,舌骨的肌肉分布和分布至舌的舌咽神经和舌下神经的分支。北京鸭的舌骨中,舌内骨分为二部;后部为骨质。前部为软骨。二部间可活动,使前部向背侧运动则舌成杓状。舌部的肌肉有角舌骨肌,领舌骨肌,舌骨领肌均为长肌,舌骨横肌,舌骨舌肌,喉基鳃骨肌和基鳃骨舌骨肌为短肌以适应舌各段的运动。舌咽神经以2—3个根发自延髓侧面。根集中至舌咽神经管出颅腔。该管长0.45厘米,比迷走神经管稍长,也稍粗。神经出颅腔后位于交感神经颈前神经节的前方。在神经干上有大的岩神经节。并自干向后有与迷走神经的交通支。神经干在下颌骨腹侧缘附近分为前后二支。前支即舌支,穿经舌骨领肌与领舌骨肌间向前沿舌骨的外侧缘,到达舌背的粘膜。后支较细分为食管支和咽支。舌下神经以一系列的根丝出于延髓后部的腹侧面。根丝集成二组,合成二干,分别穿出舌下神经孔。出颅腔后二干平行,在头大腹侧直肌的背侧与头最长肌之问。二干合并后绕至头大腹侧直肌止端腱的外侧。有分支与迷走神经和第一颈神经交通。神经干经角舌骨肌和舌骨领肌的内侧分为前后二支。前支沿角舌骨肌的内侧向前伸延,分出角舌骨肌支再向前到达舌骨的腹外侧分支入舌骨舌肌等小肌。后支...     

大学生参加城镇居民医疗保险社会学探析

对当前我国大学生参加城镇居民医疗保险的意义、存在的问题、机制等方面进行了剖析,从社会学角度对大学生参加城镇居民医疗保险工作进行探析,借鉴社会学理论,为制定适合大学生的医保政策和参保的激励机制提供科学依据和理论支持,从而改善我国大学生医疗保障状况,提出完善大学生医疗保险工作的新思路。     

非战争军事行动视角下的军事英语教学研究

就我军而言,以非战争军事行动需求为牵引,凸显军事特色英语教学,培养军校学员灵活的军事英语能力,这对于执行国际化非战争军事任务,有效履行新时期重要使命具有特殊意义。本文结合我院军事英语教学实际探讨了进一步改进军事英语教学的对策,以促进军校英语教学又好又快地发展,培养更多部队急需的新型军事人才。     

二对角反对称矩阵的正交标准型

本文给出了二对角反对称矩阵的标准形式,它在典型群的表示论和概齐次空间的研究中有着非常重要的意义.