三峡水库香溪河库湾春季水华期间悬浮物动态

在三峡水库香溪河库湾春季藻类水华期间开展了水体悬浮物动态研究.调查结果表明:总悬浮物浓度的中位数是6.80mg·L-1,波动范围是0.66～134.92mg·L-1,从河口到库尾入库点呈现逐渐递增的趋势;无机悬浮物空间格局与总悬浮物基本相似,而有机悬浮物空间格局与总悬浮物差异较大,与叶绿素a较为相似.回归分析表明:库湾中部水域叶绿素a与总悬浮物、有机悬浮物均有显著的线性关系,分别解释了总悬浮物、有机悬浮物总变异的66.7%～96.7%和58.9%～85.5%;在库湾两端(河口与库尾)叶绿素a与悬浮物参数均

鱼类生态形态学研究进展

国家自然科学基金项目(30571440); 国家科技支撑计划(2006BAD03B02); 湖北省科技攻关项目(2006AA203A03)

五里湖深水区沉水植被重建策略探索

本文以菹草(PotamogetoncrispusL.)和伊乐藻(Elodeanuttallii)为材料,在不同水深条件下对沉水植物的生长进行了研究。结果表明:随着水深的增加,菹草和伊乐藻的茎伸长速度逐渐增大,但分支数或株数减少,最终植物生物量减少;菹草和伊乐藻种群能够建立的水深极限条件分别为:2倍SD和2.3倍SD。在冬季透明度为1.1-1.2m条件下,伊乐藻种群在2.5m水深处成功建立。高透明度(>1.1m)是五里湖深水区伊乐藻种群建立的关键条件。在此研究的基础上,本文探讨了重建五里湖深水区沉水植被的可

五氯苯酚在武汉东湖底质颗粒物上的吸附研究

通过静态吸附实验,研究了五氯苯酚在武汉东湖底质颗粒物上的吸附行为,并考察了pH值、颗粒物浓度、盐度和腐殖酸对吸附行为的影响.结果表明,25℃时五氯苯酚在该颗粒物上的吸附行为可用Freundlich吸附等温式描述,在pH值3.0~10.0范围内,五氯苯酚在颗粒物上的平衡吸附量先减小后又缓慢增加;颗粒物浓度在0.1~2.0g.L-1之间变化时,东湖底质颗粒物对五氯苯酚的吸附具有浓度效应;腐殖酸和盐度在一定范围内对五氯苯酚在颗粒物上吸附行为的影响为先促进其平衡吸附量增加,然后这种促进作用趋于缓和.

中国串珠藻属的4个新记录种

记述了我国串珠藻属的 4个新记录种 ,即马赫拉串珠藻 Batrachospermum mahlacense Kum ano et Bowden-Kerby、可疑串珠藻 B.ambiguum Montagne、诺诺串珠藻 B.nonocense Kum ano et L iao和钏路串珠藻 B.kushiroenseKumano et Ohsaki

美国青蛙“旋游症”病原菌的分离鉴定及其组织病理学观察

从患有“旋游症”的美国青蛙（Ｒａｎａｇｒｙｌｉｏ）脑组织中分离出１株杆状细菌。人工注射该菌，可使健康蛙出现典型“旋游症”并引起死亡，表明该菌是引起蛙“旋游症”的病原菌。通过对菌的形态大小、生理生化及其他生物学性状的观察和测定，确认该菌为脑膜炎脓毒性黄杆菌（Ｆｌａｖｏｂａｃｔｅｒｉｕｍｍｅｎｉｎｇｏｓｅｐｔｉｃｕｍ）。组织病理学观察显示，病蛙中脑内的视盖组织细胞大量坏死，与视觉和调节平衡相关的神经纤维断裂、损坏，眼脉络膜与虹膜组织中的细胞病变严重，排列无序，微血管结构模糊不清，这应是引起病蛙泳动失调、视力丧

草鱼头肾免疫细胞超微结构的观察

光镜和电镜观察表明，草鱼头肾器官含有大量的免疫细胞，主要包括淋巴细胞、浆细胞、粒细胞、单核细胞和巨噬细胞等。其中粒细胞根据细胞质内的颗粒的形态结构和大小，又分为Ⅰ型、Ⅱ型和Ⅲ型粒细胞。

广西鲤科鱼类二新种

<正> 1981—1983年,我们在拍摄、编写《中国淡水鱼类原色图集》时,从广西采集一批鱼类标本,经鉴定其中有二新种。正模标本,编号83-IV-0388,全长183毫米,体长147毫米。副模标本7尾,编号83-IV-0008,83-IV-0085,83-IV-0384-0387,83-IV-0389,全长152一227毫米,体长121一184毫米。

20种鲤科鱼类同工酶的表型分析及有关进化问题的探讨

本文对20种鲤科鱼类的同工酶表型进行了分析比较。鲌亚科中存在几种不同的LDH同工酶表型,以各种LDH同工酶表型所组成的一些类群,反映出亚科水平中属间的亲缘关系。按同工酶的表型可将它们分为4个类群,这些类群的划分和进化趋异的过程是与经典的系统分类相一致的。按LDH同工酶表型的异同可将鲌亚科、密鲴亚科和鲢亚科的鱼类划分成两个主要的支系。一支鱼类是具有相同迁移率的LDH-A-4 同工酶,其中包括鲌亚科的多数鱼类,由LDH 同工酶的表型推断它们与雅罗鱼亚科有较密切的亲缘关系;另一支鱼类则是具有相同迁移率的 LDH

甲基睾丸酮诱导鲫鱼雌核发育子代性转化的研究

本文介绍了用甲基睾丸酮诱导鲫鱼雌核发育子代性转化的研究结果。对孵化后3天的人工雌核发育的红鲫仔鱼和天然雌核发育的银鲫仔鱼,以含有不同量的甲基睾丸酮激素饵料喂养90天,再用一般饵料喂养直到可以剖腹鉴别性别。结果是:1,喂用每克 MT_(25-30μg)激素饵料的,除 1尾发育为精卵巢外.全部试验鱼都发育成雄性;2,喂用每克含 MT_(50-100μg)激素饵料的,没有雄性鱼出现。此外,用 1ml 工业酒精同 1g饵料配制的混合饵料,喂养90天的试验鱼,有60—84.6％的个体发育成雄性。不加激素和酒精的饵料

Coagulation removal of melanoidins from biologically treated molasses wastewater using ferric chloride

The pigments (melanoidins) in molasses wastewater are refractory to conventional biological treatment. Ferric chloride was used as coagulant to remove color and chemical oxygen demand (COD) from molasses effluent. Using jar test procedure, main operating conditions such as pH and coagulant dosage were investigated. Under the optimum conditions, up to 86% and 96% of COD and color removal efficiencies were achieved. Residual turbidity in supernatant was less than 5 NTU and Fe3+ concentration was negligible because of effective destabilization and subsequent sedimentation. The results of high performance size exclusion chromatography (HPSEC) show that low molecular weight (MW) fraction of melanoidins is more reactive than high MW fraction and increase in the concentration of the lowest MW organic group is related to the capacity of charge neutralization. Aggregate size measurement reveals the size effect on the settleability of flocs formed, with larger flocs settling more rapidly. Charge neutralization and co-precipitation are proposed as predominant coagulation mechanism under the optimum conditions. (C) 2009 Elsevier B.V. All rights reserved.

Ontogeny of IgM-producing cells in the mandarin fish Siniperca chuatsi identified by in situ hybridisation

The ontogeny of IgM-producing cells was studied in juvenile mandarin fish Simperca chuatsi, an important fish in China's aquaculture sector. The IgM-producing cells were localised through in situ hybridisation with a probe complementary to the Ig mu-chain in lymphoid-related tissues, including head kidney, spleen, thymus, intestine and gills. In head kidney, transcripts of Ig mu were first detected at 20 days post-hatching (dph) with a few positive signals. and the number of IgM-producing cells increased obviously from 39 dph onwards. At 136 dph, a large amount of positive cells were observed in the entire organ with clusters of these cells located around the blood vessels. In spleen, IgM-producing cells were found from 26 dph onwards, followed by an increase until 67 dph: clusters of positive cells were also detected around blood vessels at 102 dph. In thymus, IgM-producing cells were first observed at 39 dph; thereafter, no obvious increase was detected until 78 dph. The positive cells in thymus were distributed mainly in the outer zone of thymus. A few IgM-producing cells were still observed in thymus of 1-year-old mandarin fish. IgM-producing cells were not detected in the intestine until 87 dph, with several discrete positively stained cells distributed in the lamina propria. IgM-producing cells, scattered mainly in primary gill filaments around blood vessels, were detected in gills from 90 dph. As in other teleosts, these results indicated that the head kidney appears to be the primary organ for IgM production in mandarin fish, and IgM-producing cells exist in all organs examined in the present study, implying their lymphoid role in fish. In addition, it is suggested that vaccination after 20 dph may be much more effective in mandarin fish. (C) 2009 Elsevier B.V. All rights reserved.

Predominant expression and cellular distribution of fish Agr2 in renal collecting system

Anterior gradient 2 (Agr2) genes encode secretory proteins, and play significant roles in anterior-posterior patterning and tumor metastasis. Agr2 transcripts were shown to display quite diverse tissue distribution in different species, and little was known about the cellular localization of Agr2 proteins. In this study, we identified an Agr2 homologue from gibe[ carp (Carassius auratus gibelio), and revealed the expression patterns and cellular localization during embryogenesis and in adult tissues. The full-length cDNA of CagAgr2 is 803 nucleotides (nt) with an open reading frame of 510 nt encoding 169 amino acids. The Agr2 C-terminus matches to the class I PDZ-interacting motif, suggesting that it might be a PDZ-binding protein. During embryogenesis, CagAgr2 was found to be transcribed in the mucus-secreting hatching gland from tailbud stage and later in the pharynx region, swim bladder and pronephric duct as revealed by RT-PCR and whole mount in situ hybridization. In the adult fish, its transcription was predominantly confined to the kidney, and lower transcription levels were also found in the intestine, ovary and gills. To further localize the Agr2 protein, the anti-CagAgr2 polyclonal antibody was produced and used for immunofluorescence observation. In agreement with mRNA expression data, the Agr2 protein was localized in the pronephric duct of 3dph larvae. In adult fish, Agr2 protein expression is confined to the renal collecting system with asymmetric distribution along the apical-basolateral axis. The data provided suggestive evidence that fish Agr2 might be involved in differentiation and secretory functions of kidney epithelium. (C) 2009 Elsevier Inc. All rights reserved.

Identification and characterization of hypoxia-induced genes in Carassius auratus blastulae embryonic cells using suppression subtractive hybridization

Organisms living in water are inevitably exposed to periods of hypoxia. Environmental hypoxia has been an important stressor having manifold effects on aquatic life. Many fish species have evolved behavioral, physiological, biochemical and molecular adaptations that enable them to cope with hypoxia. However, the molecular mechanisms of hypoxia tolerance in fish, remain unknown. in this study, we used suppression subtractive hybridization to examine the differential gene expression in CAB cells (Carassius auratus blastulae embryonic cells) exposed to hypoxia for 24 h. We isolated 2100 clones and identified 211 differentially expressed genes (e-value <= 5e-3; Identity > 45%). Among the genes whose expression is modified in cells, a vast majority involved in metabolism, signal transduction, cell defense, angiogenesis, cell growth and proliferation. Twelve genes encoding for ERO1-L, p53, CPO, HO-1, MKP2, PFK-2, cystatin B, GLUT1, BTG1, TGF beta 1, PGAM1, hypothetical protein F1508, were selected and identified to be hypoxia-induced using semi-quantitive RT-PCR and real-time PCR. Among the identified genes, two open reading frames (ORFs) encoding for CaBTG1 and Cacystatin B were obtained. The deduced amino acid sequence of CaBTG1 had 94.1%, 72.8%, 72.8%, 72.8%, 68.6% identity with that of DrBTG1, HsBTG1, BtBTG1, MmBTG1 and XIBTG1. Comparison of Cacystatin B with known cystatin B, the molecules exhibited 49.5 to 76.0% identity overall. These results may provide significant information for further understanding of the adaptive mechanism by which C. auratus responds to hypoxia. (c) 2008 Elsevier Inc. All rights reserved.