滇池典型区域磷与铁的形态分布规律

通过调查滇池三个湖湾不同深度水层磷与铁的形态分布,研究三个湖湾内源磷的释放规律.结果表明,在海埂湾间隙水中,磷的释放强度远高于另外两个湖湾,根据水体中各种形态磷和铁的关系,推测出在这三个湖湾中,铁结合态磷是湖水悬浮物和沉积物中一种重要的可释放磷.

我国早期的一篇淡水藻类分类学论文及其作者

在国立武昌高等师范学校编辑出版的《博物学会杂志》第一卷到第四卷 (共 4期 )上刊载的毕祖高撰写的“武昌长湖之藻类”一文是迄今所知由中国科学家研究中国标本所正式发表的淡水藻类分类学的第一篇论文 .此篇论文的发表 ,标志着中国淡水藻类的采集、调查研究和发表完全由中国人己独立承担任务并取得成绩的开始 .毕祖高是国立武昌高师博物部 1917年的毕业生 ,发表此文时 ,他是国立武昌高师附属中学的博物学教员 .

中国真缓步纲三新种及六新纪录种记述(近爪目:大生熊虫科,高生熊虫科)

记述了大生熊虫科大生熊虫属Macrobiotus一新种和三新纪录种,即神农大生熊虫,新种M.shennongensissp.nov.、桃形大生熊虫M.persimilisBinda&Pilato,1972,卷形大生熊虫M.rolleiHeinis,1921,陆栖大生熊虫M.terricolaMihelcic,1949以及趾生熊虫属一新种,即水生趾生熊虫,新种Dactylobiotusaquatilissp.nov.;高生熊虫科等高熊虫属Isohypsibius一新种和二新纪录种,即长白等高熊虫,Is.ch

草鱼出血病病毒的研究进展

根据80－90年代中国关于草鱼出血病病毒研究的进展，就草鱼出血病病毒的发现、形态结构特征、理化特性、基因组结构及其所编码的多肽、基因组的转录和翻译过程，病毒的繁殖动态、体外细胞培养特性，病毒对鱼体的致病机理和宿主范围，草鱼出血病的诊断和防治等问题进行综合评述，总结概括了草鱼出血病病毒的研究现状以及研究中需要亟待解决的问题，并提出该领域以后的重点研究方向。

池养鲤和草鱼血液学指标的研究

1.鲤鱼和草鱼的血液细胞包含红血球、淋巴球、单核球、嗜中性球、嗜酸性球及纺锤细胞。没有见到嗜碱性球。2.鲤鱼及草鱼的红血球数及血红蛋白量,在正常条件下,与水中溶氧量及成熟系数成十分显著的负相关。成熟雌鲤的红血球数(y)与溶氧量(x1)及成熟系数(x2)的迥归公式为:y=122+2.9x1-1.2x2。3.性腺发育程度及生殖活动强烈地影响鱼类血液有形成分。在生殖季节雄鱼的红血球数及血红蛋白量比雌鱼高,红血球沉降率则相反。白血球则在生殖季节及性腺退化吸收时比较活跃,而在非生殖季节两性之间无明显差异。4.发育成

Phytoremediation of triazophos by Canna indica Linn. in a hydroponic system

The phytoremediation of triazophos (O, O-diethyl-O-(1-phenyl-1, 2, 4-triazole-3-base) sulfur phosphate, TAP) by Canna indica Linn. in a hydroponic system was studied. After 21 d of exposure, the removal kinetic constant (K) of TAP was 0.0229-0.0339 d(-1) and the removal percentage of TAP was 41-55% in the plant system and the K and removal percentage of TAP were about 0.002 d(-1) and 1%, respectively, in darkness and disinfected control. However, the K and removal percentage of TAP were 0.006 d(-1) and approximately 11%, respectively, in the treatment with eluate from the media of constructed wetland. The contribution of plant to the remediation of TAP was 74% and C. indica played the most important role in the hydroponic system. Under the stress of TAP and without inorganic phosphorus nutrient, the activity of phosphatase in the plant system increased and phytodegradation was observed. The production and release of phosphatase is seen as the key mechanism for C. indica to degrade TAP. C. indica, which showed the potential of phytoremediation of TAP, and is commonly used in constructed wetland, so the technique of phytoremediation of TAP from contaminated water can be developed with the combination of constructed wetland.

Garra rotundinasus, a new species of cyprinid fish (Pisces : Teleostei) from the upper Irrawaddy River basin, China

Garra rotundinasus, a new cyprinid species from the upper Irrawaddy River basin in Yunnan, China, is herein described. It shares with G. gravelyi the presence of a snout having a poorly developed proboscis represented by a truncate area in front of the nostrils, a character distinguishing both from all other Southeast Asian and Chinese congeners. The two species are distinct in coloration, morphometric and meristic characters. The sympatrically occurring G. tengchongensis is very similar to G. rotundinasus in possessing 36-37 perforated lateral line scales, 5 or 6 scales between the anus and anal-fin origin, and an anterior position of the anus (anus to anal distance 32.1-51.8% of pelvic to anal distance). Garra rotundinasus can be differentiated from G. tengehongensis in having a more slender caudal peduncle, a larger disc and no dark central band on the dorsal fin.

Genetic diversity of common carp from two largest Chinese lakes and the Yangtze River revealed by microsatellite markers

Six polymorphic microsatellites (eight loci) were used to study the genetic diversity and population structure of common carp from Dongting Lake (DTC), Poyang Lake (PYC), and the Yangtze River (YZC) in China. The gene diversity was high among populations with values close to 1. The number of alleles per locus ranged from 2 to 11, and the average number of alleles among 3 populations ranged from 6.5 to 7.9. The mean observed (H (O)) and expected (H (E)) heterozygosity ranged from 0.4888 to 0.5162 and from 0.7679 to 0.7708, respectively. Significant deviations from Hardy-Weinberg Equilibrium expectation were found at majority of the loci and in all three populations in which heterozygote deficits were apparent. The analysis of molecular variance (AMOVA) indicated that the percent of variance among populations and within populations were 3.03 and 96.97, respectively. The Fst values between populations indicated that there were significant genetic differentiations for the common carp populations from the Yangtze River and two largest Chinese freshwater lakes. The factors that may result in genetic divergence and significant reduction of the observed heterozygosity were discussed.

alr0117, a two-component histidine kinase gene, is involved in heterocyst development in Anabaena sp PCC 7120

Anabaena sp. PCC; 7120 was mutagenized by transposon Tn5-1087b, generating a mutant whose heterocysts lack the envelope polysaccharide layer. The transposon was located between nucleotides 342 and 343 of alr0117, a 918 bp gene encoding a histidine kinase for a two-component regulatory system. Complementation of the mutant with a DNA fragment containing alr0117 and targeted inactivation of the gene confirmed that alr0117 is involved in heterocyst development. RT-PCR showed that alr0117 was constitutively expressed in the presence or absence of a combined-nitrogen source. hepA and patB, the two genes turned on during wild-type heterocyst development, were no longer activated in an alr0117-null mutant. The two-component signal transduction system involving alr0117 may control the formation of the envelope polysaccharide layer and certain late events essential to the function of heterocysts.

Molecular cloning and characterization of crucian carp (Carassius auratus L.) interferon regulatory factor 7

Interferon (IFN) can induce an antiviral state via interferon-regulatory transcription factors (IRFs), which bind to and control genes directed by the interferon-stimulated response element (ISRE). Here we describe a fish IRF, termed CaIRF7, cloned from a subtractive cDNA library which is constructed with mRNAs obtained from crucian carp (Carassius auratus L.) blastulae embryonic (CAB) cells infected by UV-inactivated GCHV and mock-infected cells. CaIRF7 cDNA was found to be 1816 bp in length, with a 42 bp 5' UTR and a 508 bp 3' UTR. The open reading frame translates into 421 amino acids in which a DNA-binding domain (DBD) containing the repeated tryptophan motif and IRFs association domain have been identified. Like chicken GgIRF3, CaIRF7 was most similar to mammalian IRF7 with 27 to 30% identity overall and some 37% identity in their DBDs. A single transcript of 1.9 kb was detected in virally induced CAB cells by virtual Northern blotting. RT-PCR analysis revealed a wide tissue distribution of CaIRF7 constitutive expression, with detectable transcript in non-infected CAB cells and various tissues of healthy crucian carp. In addition, CaIRF7 expression was differentially increased by stimulation of the CAB cells with active GCHV, UV-inactivated GCHV or CAB IFN, indicating that the activation of CaIRF7 was directly regulated by IFN. (C) 2003 Published by Elsevier Ltd.

High repetition rate Q-switched microchip Nd:YVO4 laser with pulse duration as short as 1.1 ns

We have demonstrated a compact and an efficient passively Q-switched microchip Nd:YVO4 laser by using a composite semiconductor absorber as well as an output coupler. The composite semiconductor absorber was composed of an LT (low-temperature grown) In0.25Ga0.75As absorber and a pure GaAs absorber. To our knowledge, it was the first demonstration of the special absorber for Q-switching operation of microchip lasers. Laser pulses with durations of 1.1 ns were generated with a 350 mu m thick laser crystal and the repetition rate of the pulses was as high as 4.6 MHz. The average output power was 120 mW at the pump power of 700 mW. Pulse duration can be varied from 1.1 to 15.7 ns by changing the cavity length from 0.45 to 5 mm. Pulses with duration of 1.67 and 2.41 ns were also obtained with a 0.7 mm, thick laser crystal and a 1 mm thick laser crystal, respectively. (C) 2007 Elsevier GmbH. All rights reserved.

Fracture properties of silicon carbide thin films by bulge test of long rectangular membrane

This paper reports the mechanical properties and fracture behavior of silicon carbide (3C-SiC) thin films grown on silicon substrates. Using bulge testing combined with a refined load-deflection model of long rectangular membranes, which takes into account the bending stiffness and prestress of the membrane material, the Young's modulus, prestress, and fracture strength for the 3C-SiC thin films with thicknesses of 0.40 and 1.42 mu m were extracted. The stress distribution in the membranes under a load was calculated analytically. The prestresses for the two films were 322 +/- 47 and 201 +/- 34 MPa, respectively. The thinner 3C-SiC film with a strong (111) orientation has a plane-gstrain moduli of 415 +/- 61 GPa, whereas the thicker film with a mixture of both (111) and (110) orientations exhibited a plane-strain moduli of 329 +/- 49 GPa. The corresponding fracture strengths for the two kinds of SiC films were 6.49 +/- 0.88 and 3.16 +/- 0.38 GPa, respectively. The reference stresses were computed by integrating the local stress of the membrane at the fracture over edge, surface, and volume of the specimens and were fitted with Weibull distribution function. For the 0.40-mu m-thick membranes, the surface integration has a better agreement between the data and the model, implying that the surface flaws are the dominant fracture origin. For the 1.42-mu m-thick membranes, the surface integration presented only a slightly better fitting quality than the other two, and therefore, it is difficult to rule out unambiguously the effects of the volume and edge flaws.