Identification and molecular characterization of a peritrophin-like protein from fleshy prawn (Fenneropenaeus chinensis)

Peritrophin, one of the components of the peritrophic matrix, was first isolated from the intestine of insects. It is thought to protect insects from invasion of microorganisms and to stimulate digestion of food. Peritrophin-like proteins have also been found in crustaceans, as a component of the egg layer. In this study, one fragment of the peritrophin-like gene was obtained from fleshy prawn (Chinese shrimp) (Fenneropenaeus chinensis) by panning the T7 phage display library constructed with the shrimp hemocyte cDNA. The total sequence of the peritrophin cDNA was cloned by modified SMART cDNA and LD-PCR methods. The full cDNA is 1048 bp and the deduced protein is composed of 274 amino acids, including 21 amino acid signal peptide, and four peritrophin A domains and the latter three forming three chitin-binding domains. Similarity analysis results showed that the peritrophin-like protein from F chinensis has significant similarities with peritrophin-like and cortical rod proteins from other shrimp. It was inducing expression in hemocytes, heart, stomach, gut, and gills of the infected shrimp, and constitutive expression in the ovaries. No expression signal was detected in the hepatopancreas of either infected or noninfected shrimp. The recombinant peritrophin-like protein has the activity of binding Gram-negative bacteria and strong binding activity to chitin. Therefore, the bacteria and chitin binding activities of the peritrophin-like protein suggest that it may plays a role in immune defense and other physiological resposes. (c) 2005 Elsevier Ltd. All rights reserved.

Cadinane Sesquiterpenes from the brown alga Dictyopteris divaricata

Seven new cadinane sesquiterpenes, (-)-(1R,6S,7S,10R)-1-hydroxycadinan-3-en-5-one (1), (+)-(1R,5S,6R,7S, 10R)-cadinan-3-ene-1,5-diol (2), (+)-(1R,5R,6R,7S,10R)-cadinan-3-ene-1,5-diol (3), (+)-(1R,5S,6R,7S,10R)-cadinan-4(11)-ene-1,5-diol (4), (+)-(1R,5R,6R,7R,10R)-cadinan-4(11)-ene-1,5,12-triol (5), (-)-(1R,4R,5S,6R,7S, 10R)-cadinan-1,4,5-triol (6), and (-)-(1R,6R,7S,10R)-11-oxocadinan-4-en-1-ol (7), together with nine known compounds were isolated from the brown alga Dictyopteris divaricata. The structures of the new natural products, as well as their absolute configuration, were established by means of spectroscopic data including IR, HRMS, 1D and 2D NMR, single-crystal X-ray diffraction, and CD. All compounds were inactive against several human cancer cell lines including lung adenocarcinoma (A549), stomach cancer (BGC-823), breast cancer (MCF-7), hepatoma (Bel7402), and colon cancer (HCT-8) cell lines.

低感应数条件下大地电导率测量方法研究

A frequency domain electromagnetic (conductivity) method for near surface soundings at low frequencies is discussed in this thesis. Its elementary principle is to detect the conductivity of the earth by the secondary magnetic fields induced by a current dipole on the earth. According to the EM induction theory, a coil with alternating current on the earth will generate a magnetic field in whole space which is referred to as the primary field Hp. The primary field would induce secondary currents in the earth which go down to depth like a batch of smoking rings. These currents further produce secondary magnetic field Hs .The primary and secondary magnetic fields are collected together by a receiver coil. Generally speaking，the secondary magnetic field is a complicated function of coil spacing, transmitting frequency and earth conductivity. But at low induction numbers, the secondary field is deduced to as a simple function of frequency, spacing and conductivity. Especially the ratio of secondary to primary field shares a linear proportion to the apparent conductivity. The earth conductivity can be interpreted by proper inversions with the apparent conductivity. The method is discussed at three steps: (1)Derivation of primary and secondary magnetic fields arising from vertical and horizontal magnetic dipoles on the earth based on the basic EM induction theory. (2)Field techniques and equipment developed for the method. (3)An interpretation technique was introduced using a cumulative and relative response function. Finally a test example is presented for examining the effectiveness of the method.

月表有效太阳辐照度实时模型

月表太阳辐射是深入研究月表温度分布的关键问题之一.本文根据月表有效太阳辐照度与太阳常数、太阳辐射入射角以及日月距离之间的关系,建立月表有效太阳辐照度的实时模型.该模型在1950-2050年的100年内的理论误差百分比小于0.28%,相对前人提出的模型在精度上有了很大程度的提高,能较为真实地反映月表有效太阳辐照度随时间的变化规律.计算结果表明2007年月表太阳辐照度的年变化范围在1321.5-1416.6 W·m^-2之间,平均为1368.0 W·m^-2.通过对月表太阳辐射入射角计算结果的分析,证实了月球的两极可能存在极昼极夜.

元素在气相中迁移的实验研究进展

气相对金属的搬运早在1644年就被人们注意到了，但是长期以来由于对金属气相迁移能力的认识不足和技术手段等原因，这方面的研究工作还很薄弱。对近些年来金属元素在气相中迁移的实验研究及其地质证据等方面的工作概况进行了论述，认为金属的气相迁移是由于金属和气体溶剂问发生反应，形成金属(氯化物)水合物，增大了金属在气相中的溶解度，而并不完全取决于金属元素的挥发性。这一认识对研究元素的气相迁移，尤其是挥发性相对弱的金属元素在气相中的活动行为十分重要。随着研究的深入与基础数据的积累，元素在气相中的迁移及其对金属成矿的重要作用必将引起人们的足够重视。