Identification of the DDAH2 Protein in Pig Reproductive Tract Mucus: A Putative Oestrus Detection Marker

Precisely detecting oestrus is important for artificial insemination. The aims of this study were to identify oestrus‐specific sow mucus proteins to determine the optimal time for artificial insemination. The proestrous‐ and oestrous‐stage mucus proteins were purified and analysed with proteomic tools such as two‐dimensional gel electrophoresis and matrix‐assisted laser desorption/ionization–time‐of‐flight analyses. Among the differentially expressed proteins, the dimethylarginine dimethylaminohydrolase 2 (DDAH2) protein showed a 3.6‐fold increase during the proestrous stage compared to that during the oestrous stage. A western immunoblot study revealed that two of three sow mucus samples clearly showed negative anti‐DDAH2 antibody activity during the oestrous stage. This study demonstrated that the pig DDAH2 mucus protein exists during the proestrous stage, but not during the oestrous stage, suggesting that mucus DDAH2 could be useful as an oestrus detection marker.     

Indices of water quality for sustainable management and conservation of an arid region lake,Lake Kinneret (Sea of Galilee), Israel

1. Economic development in arid regions is closely linked to efficient use of limited water resources. As such, management and conservation of these water resources requires concurrent optimization of the interrelationships between supply quantity and resource quality. 2. Multiple uses of water resources generate conflicting needs within management, with different uses requiring objective characterization of quality for different management scenarios and goals. 3. A sound management programme needs close interactions between water policy makers, managers, users, engineers and limnologists, and thus needs a common language that can transcend the boundaries of the individual fields. 4. This paper describes a system of water quality indices and standards designed for conservation and sustainable management of Lake Kinneret (Sea of Galilee), Israel, based on observed variability in various chemical and biological parameters during a 25‐year period (1969–1992). Such a system can form a common language which can then be used as a tool for optimal management. 5. This system of water quality indices (a) includes both traditional limnological parameters (plant nutrients, chlorophyll, primary production) and engineering parameters (coliform bacteria, turbidity), (b) is acceptable to all parties involved in lake management, and (c) is easily adaptable to different management scenarios and to management‐induced changes in ecosystem functioning. 6. Analysis of variability in these water quality parameters in Lake Kinneret during 1994–1999 when the lake was showing signs of destabilization highlights the usefulness and limitations of this system. Copyright © 2000 John Wiley & Sons, Ltd.     

糖源对棉花花药培养的影响──Ⅰ 糖源对棉花花药愈伤组织诱导的影响

糖源在棉花花药培养中起着重要作用,不同糖源所起的作用不同。可溶性淀粉、蔗糖和葡萄糖有利于棉花花药愈伤组织的诱导和生长;麦芽糖对花药愈伤组织的诱导和生长促进作用不大;乳糖不利于愈伤组织的诱导。甘露醇的添加抑制了愈伤组织的诱导和生长。不同糖浓度对棉花花药愈伤组织诱导和生长的影响也不同,一般低浓度糖易诱导形成愈伤组织和愈伤组织的快速增殖。蔗糖的最佳使用浓度为３０ｇ／Ｌ。在不含糖源的培养基上棉花花药不能诱导形成愈伤组织,继代培养的愈伤组织也不易生长。培养条件和基因型也影响着糖源的使用效果。当以淀粉为糖源时,其具有胞外水解作用。     

DNA-templated carbon nanotube field-effect transistor

The combination of their electronic properties and dimensions makes carbon nanotubes ideal building blocks for molecular electronics. However, the advancement of carbon nanotube-based electronics requires assembly strategies that allow their precise localization and interconnection. Using a scheme based on recognition between molecular building blocks, we report the realization of a self-assembled carbon nanotube field-effect transistor operating at room temperature. A DNA scaffold molecule provides the address for precise localization of a semiconducting single-wall carbon nanotube as well as the template for the extended metallic wires contacting it.     

Neutralization of the AIDS retrovirus by antibodies to a recombinant envelope glycoprotein

Mammalian cell lines have been engineered to produce a secreted form of the AIDS retrovirus envelope glycoprotein. The recombinant protein has been isolated from growth-conditioned culture media and used to immunize animals. Antibodies directed against the recombinant molecule were found to react with the envelope glycoprotein produced in virus-infected cells. Furthermore, these antibodies were able to directly inactivate the AIDS retrovirus in a neutralization assay in vitro. The expression system reported here should provide sufficient quantities of the AIDS retrovirus envelope protein for biological and vaccination studies.     

Total alignment of calcite at acidic polydiacetylene films: cooperativity at the organic-inorganic interface

Biological matrices can direct the absolute alignment of inorganic crystals such as calcite. Cooperative effects at an organic-inorganic interface resulted in similar co-alignment of calcite at polymeric Langmuir-Schaefer films of 10,12-pentacosadiynoic acid (p-PDA). The films nucleated calcite at the (012) face, and the crystals were co-aligned with respect to the polymer's conjugated backbone. At the same time, the p-PDA alkyl side chains reorganized to optimize the stereochemical fit to the calcite structure, as visualized by changes in the optical spectrum of the polymer. These results indicate the kinds of interactions that may occur in biological systems where large arrays of crystals are co-aligned.     

Urinary metabolites in congenital hyperuricosuria

The excretion of oxypurine metabolites in urine of patients with congenital hyperuricosuria exceeds, on a creatinine basis, that observed in any previously recognized metabolic anomaly. The ratio of hypoxanthine to xanthine is from 2:1 to 3:1 and results from increased hypoxanthine excretion, in contrast to other hyperuricosuric conditions where ratios of less than one have been reported. Administration of allopurinol (a xanthine-oxidase inhibitor) reduces the excretion of uric acid but results in an equivalent increase in xanthine and hypoxanthine. These features appear to be unique to congenital hyper-uricosuria.