云南滇池濒危特有种滇池金线鲃人工繁殖初报

滇池金线鲃(Sinocyclocheilus grahami)是滇池湖泊生态系统的指示物种和特有种.因水质污染和外来物种入侵等因素的影响,该鱼类自1986年起就从湖体中消失,仅有湖周围的少数龙潭中尚保存有少量滇池金线鲃.至2007年3月初,有两次繁殖试验取得了成功.先后试验了5尾雌鱼和6尾雄鱼,获得鱼卵约1 600粒,并实施干法受精.约有1 320粒受精,平均受精率为73%.孵化出鱼苗约480尾,平均孵化率为36%.经10天饲养,约有95%以上的鱼苗存活,体长达8-12 mm.滇池金线鲃人工繁殖成功的意义有三点:能有效保护该物种免于灭绝;繁殖的鱼苗放归湖泊合适水域,将有助于恢复滇池的土著生物多样性;有助于推动当地水产养殖业从非土著鱼类养殖向土著鱼类养殖的方向转变.

福尔马林固定白鲟(Psephurus gladius)标本的DNA提取及其相近种微卫星引物的适用性

白鲟是是世界上最大的淡水鱼之一,为我国独有,被誉为"长江中的活化石".目前白鲟群体已极度濒危,获取其新鲜材料非常困难,因此本文以保存于中科院水生所标本馆的福尔马林固定白鲟标本为研究材料,尝试从其肌肉、心脏、鳍条和肝脏组织提取白鲟基因组DNA,并检验相近种匙吻鲟和中华鲟微卫星引物对白鲟有无适用性.实验包括福尔马林固定白鲟标本从组织预处理到消化、抽提等步骤的整体优化过程;通过一系列对比试验分析在不同条件下提取到基因组DNA片段大小的差异,最终实现了福尔马林固定白鲟标本基因组DNA的稳定提取,并提出后续实验的延

高浓度CO_2对极大螺旋藻生长和光合作用的影响

以极大螺旋藻作为实验材料 ,研究了高CO2 浓度对极大螺旋藻的生长和光合作用效应 ,结果表明在高光强下 (40 0 μmolm- 2 s- 1 ) ,高浓度CO2 对其生长和光合作用有明显的影响 ,高浓度CO2 培养下 ,螺旋藻的比生长速率是低浓度CO2 培养的 1 2倍 ;而在低光强下 ,高浓度CO2 对其生长和光合作用无明显影响。两种不同CO2 浓度和光强下培养的极大螺旋藻 ,在不同的生长时期 ,分别测定其P -I曲线 ,结果表明低光强下培养的极大螺旋藻 ,在 5d、8d、1 1d ,两者的Ik、α值

分形理论对水生态系统空间格局研究初探

首先对分形理论在生态学中的应用情况作了简要介绍，然后应用它对梅子垭水库的藻类叶绿素a浓度场水平2维空间格局进行了分析，通过对不同时间各浓度轮廓线的空间占据能力进行比较分析，确定了各浓度的稳定程度。可由此说明浮游植物的变化情况和生长潜力。

Immunoglobulin joining (J) chain and its expression in the Chinese soft-shelled turtle (Pelodiscus sinensis)

The immunoglobulin (Ig) joining (J) chain plays an important role in the formation of polymeric Igs and their transport into secretions. In the present study, the cDNA sequence of J chain has been cloned from the Chinese soft-shelled turtle (Pelodiscus sinensis) by reverse transcription (RT)-PCR and rapid amplification of cDNA ends (RACE). The cDNA sequence is 2347 bp in length and contains an open reading frame of 480 bp encoding 160 aa including the signal sequence. The deduced amino acid sequence has a high degree of homology with that of an already reported turtle J chain (80.7%), and of chicken (71.3%). By using real-time quantitative RT-PCR analysis, a significant up-regulation of J-chain transcripts was observed in spleen, kidney and blood of turtles injected with inactivated Aeromonas hydrophila, indicating the immune role of J chain in response to bacterial infection. (C) 2009 Elsevier B.V. All rights reserved.

Antimicrobial activity-specific to Gram-negative bacteria and immune modulation-mediated NF-kappa B and Sp1 of a medaka beta-defensin

Defensins are a group of cationic antimicrobial peptides which play an important role in the innate immune system by exerting their antimicrobial activity against pathogens. In this study, we cloned a novel beta-defensin cDNA from medaka (Oryzias latipes) by rapid amplification of cDNA ends (RACE) technique. The full-length cDNA consists of 480 bp, and the open reading frame (CRF) of 189 bp encodes a polypeptide of 63 amino acids (aa) with a predicted molecular weight of 7.44 kDa. Its genomic organization was analyzed, and Southern blot detection confirmed that only one copy of beta-defensin exists in the medaka HNI strain. RT-PCR, Western blot and immunohistochemistry detections showed that the beta-defensin transcript and protein could be detected in eyes, liver, kidney, blood, spleen and gill, and obviously prevalent expression was found in eyes. Antimicrobial activity of the medaka beta-defensin was evaluated, and the antibacterial activity-specific to Gram-negative bacteria was revealed. Furthermore, the lipopolysaccharide (LPS), a major component of the outer membrane of Gram-negative bacteria, was demonstrated to be able to induce about 13-fol up-regulation of the beta-defensin within first 12 h. In addition, promoter and promoter mutagenesis analysis were performed in the medaka beta-defensin. A proximal 100 base pair(bp) sequence (+26 to -73)and the next 1700 bp sequence (-73 to -1755) were demonstrated to be responsible for the basal promoter activity and for the transcription regulation. Three nuclear factor kappa B (NF-kappa B) cis-elements and a Sp1 cis-element were revealed by mutagenesis analysis to exist in the 5' flanking sequence, and they were confirmed to be responsible for the up-regulation of medaka beta-defensin stimulated by LPS. And, the Sp1 cis-element was further revealed to be related to the basal promoter activity, and transcriptional factor II D (TFIID) was found to be in charge of the gene transcription initiation. All the obtained data suggested that the novel medaka beta-defensin should have antimicrobial activity-specific to Gram-negative bacteria, and the antibacterial immune function should be modulated by NF-kappa B and Sp1. (C) 2008 Elsevier Ltd. All rights reserved.

Effects of solar ultraviolet radiation on the photochemical efficiency, photosynthetic pigments and biomass production of Spirulina platensis

Effects of solar ultraviolet radiation (UVR) on Spirulina platensis were studied by investigating its photochemical efficiency, photosynthetic pigments and biomass production while exposed to full spectrum solar radiation or depleted of UVR for understanding how and to what extent UVR influences its photosynthetic physiology and production. It was found that UVR brought about an extra inhibition of photochemical efficiency by 26%-30%. The greatest inhibition of photochemical efficiency in S. platensis was observed at noontime, and then recovered to some extent in late afternoon no matter which treatment they were exposed to. The contents of chlorophyll a, phycocyanin and carotenoids increased during initial stage of the exposure, but decreased with elongated exposure. UVR decreased the biomass yield by about 6%. It indicated that filtering out UVR of solar radiation would raise the productivity of S. platensis, which is an important factor that should be considered in the production.

Construction and characterization of a novel recombinant single-chain variable fragment antibody against White Spot Syndrome Virus from shrimp

An antibody phage display library against White Spot Syndrome Virus (WSSV) was constructed. After four rounds of panning against WSSV, 192 out of 480 clones displayed WSSV binding activity. One of the positive clones, designated A1, had relatively higher activity specifically binding to WSSV A1-soluble, single-chain fragment variable (scFv) antibody has an affinity constant (K-aff) of 2.02 +/- 0.42 x 10(9) M-1. Dot blot assays showed that A1-soluble scFv could detect WSSV directly from shrimp hemolymph after 24-h feeding infection by WSSV. A1 scFv has potential for the development of a cheap, simple and sensitive diagnostic kit for WSSV in the field. (C) 2003 Elsevier Science B.V. All rights reserved.

First-Principles Study of Magnetic Properties of 3d Transition Metals Doped in ZnO Nanowires

The defect formation energies of transition metals (Cr, Fe, and Ni) doped in the pseudo-H passivated ZnO nanowires and bulk are systematically investigated using first-principles methods. The general chemical trends of the nanowires are similar to those of the bulk. We also show that the formation energy increases as the diameter of the nanowire decreases, indicating that the doping of magnetic ions in the ZnO nanowire becomes more difficult with decreasing diameter. We also systematically calculate the ferromagnetic properties of transition metals doped in the ZnO nanowire and bulk, and find that Cr ions of the nanowire favor ferromagnetic state, which is consistent with the experimental results. We also find that the ferromagnetic coupling state of Cr is more stable in the nanowire than in the bulk, which may lead to a higher T (c) useful for the nano-materials design of spintronics.

Microstructural and compositional characteristics of GaN films grown on a ZnO-buffered Si(111) wafer

Polycrystalline GaN thin films have been deposited epitaxially on a ZnO-buffered (111)-oriented Si substrate by molecular beam epitaxy. The microstructural and compositional characteristics of the films were studied by analytical transmission electron microscopy (TEM). A SiO2 amorphous layer about 3.5 nm in thickness between the Si/ZnO interface has been identified by means of spatially resolved electron energy loss spectroscopy. Cross-sectional and plan-view TEM investigations reveal (GaN/ZnO/SiO2/Si) layers exhibiting definite a crystallographic relationship: [111](Si)//[111](ZnO)//[0001](GaN) along the epitaxy direction. GaN films are polycrystalline with nanoscale grains (similar to100 nm in size) grown along [0001] direction with about 20degrees between the (1 (1) over bar 00) planes of adjacent grains. A three-dimensional growth mode for the buffer layer and the film is proposed to explain the formation of the as-grown polycrystalline GaN films and the functionality of the buffer layer. (C) 2004 Elsevier Ltd. All rights reserved.

Optical properties of boron-doped Si nanowires

Raman scattering and photoluminescence (PL) of boron-doped silicon nanowires have been investigated. Raman spectra showed a band at 480 cm(-1), indicating that the crystallinity of the nanowires was suppressed by boron doping. PL taken from B-doped SiNWS at room temperature exhibited three distinct emission peaks at 1.34, 1.42. and 1.47 eV and the PL intensity was much stronger than that of undoped SiNWS. The increased PL intensity should be very profitable for nano-optoelectronics. (C) 2004 Elsevier B.V. All rights reserved.

Structure and magnetic properties of ScFe6Ga6-type RCo5Ga7 (R = Y, Tb, Dy, Ho and Er)

The structure and magnetic properties of the RCo5Ga7 (R = Y, Tb, Dy, Ho and Er) compounds with the ScFe6Ga6-type structure have been studied. The stability of RCo5Ga7 is closely related with the ratio of the metal radii R-RE/R-(Co,R-Ga). With R-RE/R-(Co,R-Ga) less than or equal to 1.36, the compounds can be stabilized in the ScFe6Ga6-type structure. The lattice of RCo5Ga7 shrinks as the atomic order of R increases, and it is consistent with the lanthanide contraction. The structure analysis based on X-ray diffraction patterns reveals that in the orthorhombic RCo5Ga7 (Immm), R occupies the 2a site, and Co enters into the 8k and the 4h sites, and Ga is at the 4e, 4f, 4g, 4h and 8k sites. The interatomic distances and the coordination numbers of RCo5Ga7 are provided from the refinement results. The short interatomic distance (less than 2.480 Angstrom) between the Co ions results in the negative magnetic interaction, which does not favor ferromagnetic ordering. The magnetic moment of YCo5Ga7 is absent, and RCo5Ga7 (R = Tb, Dy, Ho and Er) may have long-range magnetic ordering with the paramagnetic Curie temperature lower than 5 K. (C) 2004 Elsevier Inc. All rights reserved.