基于四个线粒体基因片段的银鱼科鱼类系统发育

银鱼科鱼类是我国重要的经济鱼类,但其属间系统发育关系与属、种的界定尚存争议。研究使用线粒体12S/16S核糖体RNA、细胞色素c氧化酶亚基Ⅰ(COⅠ)基因部分序列以及NADH脱氢酶亚基1全长序列重建银鱼科属间的系统发育。结果显示银鱼科鱼类是单系群,白肌银鱼属在银鱼系统发育的基部,"大银鱼属+新银鱼属"、"间银鱼属+银鱼属"形成两个单系亚群,但日本银鱼属的位置没有很好解决。基于COI基因序列计算的"短吻-陈氏-太湖-近太湖新银鱼复合群"种间遗传距离为0—0.19%、"乔氏-寡齿新银鱼复合群"种间遗传距离为0%。整合研究结果与前人形态、分子证据,详细地讨论了银鱼的属、种分类。     

鄱阳湖银鱼多样性及其时空格局

采用专门设计的银鱼拖网系统地调查了鄱阳湖银鱼夏季索饵期和春季产卵期的空间分布格局.结果显示鄱阳湖银鱼物种多样性低、空间分布不均匀;3种银鱼的相对丰度差异悬殊,小型物种寡齿新银鱼相对丰度最高（71.5%）,体型中等的太湖新银鱼次之（25.6%）,而体型较大的短吻间银鱼相对丰度最低（2.9%）.春季银鱼空间分布不均匀,南部受保护区域丰富度（R）高于北部受干扰生境;产卵场分布格局种间差异显著：2种新银鱼南北都有分布,寡齿新银鱼分布最广（发生率IO=70.0%）,太湖新银鱼次之（IO=55.0%）,而短吻间银鱼仅见于南部水域（IO=30.0%）.夏季银鱼分布广泛,种间分布格局相近,彼此相关显著.表明鄱阳湖银鱼区系多样性结构与其产卵场分布格局和状况相关,而受夏季银鱼索饵场空间布局影响不大.以物种多样性参数为变量的聚类分析将40个调查样点聚为6类,其中3类生境对银鱼区系稳定贡献显著,应受到优先保护.     

滴滴涕对太湖经济鱼类危害的生态风险

选取滴滴涕(diehloro-diphenyl-trichloro-ethane,DDT)作为太湖持久性有机氯污染的代表性污染物,以大银鱼、陈氏短吻银鱼和刀鲚为研究对象,建立太湖主要经济鱼类食物网模型,并结合DDT的生物化学特性以及蒙特卡罗(Monte Carlo)不确定性分析方法,应用食物网模型研究DDT在食物网主要经济鱼类中的迁移分布特性,分析由此导致的生态风险.结果表明:大银鱼DDT累积量为0～0.329 mg·kg-1,平均值为0.039 mg·kg-1;陈氏短吻银鱼DDT累积量为0-0.188 mg·kg-1,平均值为0.022 mg·kg-1;刀鲚DDT累积量为0-0.575 mg·kg-1,平均值为0.067 mg·kg-1;以脂溶性为代表的污染物累积性质是太湖经济鱼类富集DDT的主要控制因素;生态风险总体状况为:刀鲚＞大银鱼＞陈氏短吻银鱼.     

太湖新银鱼线粒体D-loop和Cytb片段序列结构与进化速率比较

共获得49个太湖新银鱼(Neosalanx taihuensis)个体的线粒体细胞色素b(Cyt b)全序列和控制区(D-loop)部分序列。所测线粒体D-loop部分序列长度变化范围为648～680bp,识别到位于前端的一个串联重复序列、一个终止相关序列(ETAS),3个中央保守区保守序列(CSB-F、CSB-E、CSB-D)及一个保守序列区保守序列(CSB-1),结构与其他鱼类的研究结果类似。太湖新银鱼线粒体Cyt b和D-loop片段的相对进化速率的比较研究结果表明,太湖新银鱼D-loop总的序列多态性位点的比例为0.83%,低于线粒体Cyt b部分总的序列多态性位点的比例(1.31%)。假设太湖新银鱼Cyt b基因平均进化速率相对值为1,贝叶斯(Bayes)MCMC模拟给出Cyt b基因的相对速率区间估计为1.000±0.131,而D-loop基因的相对速率为0.859±0.261,表明太湖新银鱼D-loop基因的进化速率低于Cyt b基因,同时,后验概率分布的变异方差也比较大。说明Cyt b基因比D-loop基因具有相对较高的进化速率,也相对更接近分子钟假设。因此,可以认为Cyt b基因比D-loop基因更适于太湖新银鱼种内及近缘种间相关分子生态及系统地理格局的研究。     

基于稳定同位素技术的三峡库区短颌鲚营养生态位特征研究

为了预测三峡库区外来鱼类短颌鲚（Coilia nasus）在库区的种群发展趋势,评估其对库区水域生态系统的影响,基于碳氮稳定同位素技术,分析了三峡库区腹地,包括长江一级支流草堂河、大宁河,现有短颌鲚及杂食性和肉食性典型鱼类的营养级,在此基础上选择4种与短颌鲚营养级相近（包括太湖新银鱼Neosalanx taihuensis、翘嘴鲌Culter alburnus、鳡Elopichthys bambusa、大眼鳜Siniperca kneri）,及1种食谱存在较大重叠的鱼类（即鳙Aristichthys nobilis）,探讨了其营养生态位特征。结果显示,三峡库区短颌鲚δ¹⁵N值分布范围为12.112‰-14.497‰,营养级为3.762±0.196（Mean±SD）,低于太湖新银鱼,并高于大眼鳜、翘嘴鲌、鳡及鳙;三峡库区短颌鲚δ¹³C值分布范围为-27.236‰- -22.952‰,变幅低于鳙,高于太湖新银鱼、大眼鳜、翘嘴鲌及鳡,δ¹³C值分布频率呈单峰型与太湖新银鱼高度接近,表明短颌鲚在该水域食性广泛,且与太湖新银鱼的摄食偏好趋近。据此推测三峡库区短颌鲚营养级较高的主要原因是短颌鲚在三峡库区食物来源广泛,决定其富集¹⁵N途径可能更丰富。此外,营养生态位分析结果显示三峡库区短颌鲚营养生态位宽幅低于鳡、鳙,高于太湖新银鱼、翘嘴鲌、大眼鳜,据此推测三峡库区短颌鲚对饵料需求的特化程度可能不高,从营养角度对环境的适应性较强;且其与营养级相近鱼类的营养生态位重叠程度较低,存在明显的营养生态位分化,种间竞争不激烈。综上所述,从目前三峡库区现有短颌鲚营养生态位特征来看,其种群规模仍有进一步扩大的可能。上述研究结果可为全面了解三峡库区外来鱼类的适应对策提供研究思路和基础数据。     

不同温度对太湖短吻银鱼秋季孵化的试验研究

太湖短吻银鱼是太湖的主要经济鱼类之一。本文在1975和1981年对不同温度下太湖短吻银鱼秋季人工授精孵化进行了8次试验,胚胎发育和孵化仔鱼均属正常,并得到如下统计分析结果: 1.在试验温度范围内孵化温度与积算温度(A)的相关为A=3441.97-93.41t; 2.孵化温度与孵化时间(H)的相关为logH=4.3615-1.8946logt; 3.孵化温度与初孵仔鱼全长(L)的相关为logL=1.0917-0.5246logt。     

江湖阻隔对短吻间银鱼空间发生格局的影响

基于2001–2003年长江流域86个水体短吻间银鱼资源的连续调查,本文报道了短吻间银鱼(Hemisalanxbrachyrostralis)在流域尺度上的分布格局和年度动态,分析了其时空分布格局与湖泊面积和隔离因子间的关系,探讨了流域江-湖水网系统破碎化对短吻间银鱼种群结构和动态的影响。结果显示短吻间银鱼仅分布于葛洲坝以下的长江中下游,发生率低(年均21.3%),空间发生格局年度变动频率高,种群稳定性低。调查湖泊内目标种发生率、种群稳定性均与湖泊面积呈正相关关系,而与湖泊隔离系数呈负相关关系;三年的发生格局始终极显著地正相关于湖泊的面积因子,同时负相关于湖泊的隔离因子。表明江湖阻隔所引发的湖泊水面缩减和湖间隔离度增大对短吻间银鱼资源产生了深刻的影响,对其空间格局的形成贡献显著。     

徐家河水库陆封近太湖新银鱼生物学研究

1992年5月至1996年8月对徐家河水库近太湖新银鱼的形态学,繁殖特性,生长以及食性进行了研究。结果表明,徐家河水库近太湖新银鱼主要以枝角类和桡足类为食,繁殖季节为3-6月,其中4月中旬为繁殖高峰期,与太湖新银鱼不同只有春季产卵群体,生命周期为一年。体重与体长关系为:W=2.014×10-6L3.170(r=0.999)。其von Benrtalanffy生长方程为Lt=65.071-e-0.2394(t+0.5066)forbody length and Wt=1.1281-e-0.2394(t+0.5066)3.170。       

洪泽湖大银鱼和太湖新银鱼的生长、死亡参数及资源利用状况

2015年7月至2016年6月采用银鱼拖网对洪泽湖大银鱼和太湖新银鱼进行周年逐月采样, 确定单位水体面积(1 km2)捕捞渔获量, 估算种群生长和死亡相关参数; 利用平衡产量模型评估获得最高单位补充量渔产量时的最适开捕时间, 并设定为优化的管理方案; 构建单位补充量产卵群体生物量(Spawner biomass per-recruitment; SBR)模型, 评估洪泽湖银鱼资源在当前和优化管理方案下的捕捞利用状况, 为其资源管理提供指导。研究结果表明, 大银鱼体长和体重分别为29.0—182.6 mm和0.10—34.79 g, 世代周期中存在2个快速生长阶段, 即4—6月和8—11月; 最适生长方程为von Bertalanffy方程, L_t=173.35×[1–e–1.972(t–0.092)]; 捕捞死亡系数和自然死亡系数分别为8.583/year和3.292/year。太湖新银鱼体长和体重分别为20.4—82.7 mm和0.04—3.40 g, 整个世代周期持续生长, 最适生长方程为Logistic方程, L_t=66.82/[1+e–5.386(t–0.124)]; 捕捞死亡系数和自然死亡系数分别为7.006/year和1.146/year。平衡产量模型结果显示, 当大银鱼开捕年龄为0.593 year, 太湖新银鱼开捕年龄为0.420 year时, 即将银鱼开捕时间由现行的8月9日, 推迟20d, 并取消现行的5月一周捕捞, 可以获得最大总渔产量。SBR模型评估结果显示, 在当前管理模式下, 大银鱼SBR残存量相当于未开发状态的20.23%, 优化管理方式后可达到36.72%, 能有效缓解大银鱼的捕捞压力; 在优化管理方式后, 大湖新银鱼的SBR残存量从现行管理方式下相当于未开发状态的7.50%, 提升至12.86%, 但仍低于20%。     

太湖短吻银鱼春季早期胚胎发育以及温度与其孵化关系的研究

一、目的和意义 太湖短吻银鱼Neosalanx tangkahkeii taihuensis Chen为太湖中的名贵鱼类之一,也是太湖中的优势种类之一。调源丰富,产量较高。渔产品除供应国内市场外,又为我国主要出口水产品之一。根据过去记载,渔产量不断提高,尤以今年上半年又获较大丰收(接近100万斤),就春季繁殖生长的个体,在银鱼汛期的种群分析中占有一半左右(另一半为秒季繁殖的个体)。由于这一鱼类古今中外久享盛名,目前已列入国家水产资源中的重点繁殖保护对象之一。关于它在春季生殖时期的发育和孵化规律方面,目前尚缺乏参考资料。为此,作     

Identification key for European strand-forming house-rot fungi

An identification key for 20 common strand-forming indoor wood decay fungi is given. The key is based on observations of material from affected buildings and on wood samples that have been incubated in the laboratory. The key is with macro- and microscopic photographs.     

Semicircular canal system in early primates

Mammals with more rapid and agile locomotion have larger semicircular canals relative to body mass than species that move more slowly. Measurements of semicircular canals in extant mammals with known locomotor behaviours can provide a basis for testing hypotheses about locomotion in fossil primates that is independent of postcranial remains, and a means of reconstructing locomotor behaviour in species known only from cranial material. Semicircular canal radii were measured using ultra high resolution X-ray CT data for 9 stem primates (“plesiadapiforms”; n = 11), 7 adapoids (n = 12), 4 omomyoids (n = 5), and the possible omomyoid Rooneyia viejaensis (n = 1). These were compared with a modern sample (210 species including 91 primates) with known locomotor behaviours. The predicted locomotor agilities for extinct primates generally follow expectations based on known postcrania for those taxa. “Plesiadapiforms” and adapids have relatively small semicircular canals, suggesting they practiced less agile locomotion than other fossil primates in the sample, which is consistent with reconstructions of them as less specialized for leaping. The derived notharctid adapoids (excluding Cantius) and all omomyoids sampled have relatively larger semicircular canals, suggesting that they were more agile, with Microchoerus in particular being reconstructed as having had very jerky locomotion with relatively high magnitude accelerations of the head. Rooneyia viejaensis is reconstructed as having been similarly agile to omomyids and derived notharctid adapoids, which suggests that when postcranial material is found for this species it will exhibit features for some leaping behaviour, or for a locomotor mode requiring a similar degree of agility.     

Bacterial flora in the alimentary tract of chickens infected with Eimeria brunetti and in chickens immunized with Eimeria maxima and cross-infected with Eimeria brunetti

Differential bacterial counts were made on the intestinal and caecal contents of chickens after inoculation with a standard dose of 320 000 freshly sporulated oocysts of Eimeria brunetti.     

Analysis of the molecular cascade responsible for mesodermal limb chondrogenesis: Sox genes and BMP signaling

Here, we have studied how Sox genes and BMP signaling are functionally coupled during limb chondrogenesis. Using the experimental model of TGFbeta1-induced interdigital digits, we dissect the sequence of morphological and molecular events during in vivo chondrogenesis. Our results show that Sox8 and Sox9 are the most precocious markers of limb cartilage, and their induction is independent and precedes the activation of BMP signaling. Sox10 appears also to cooperate with Sox9 and Sox8 in the establishment of the digit cartilages. In addition, we show that experimental induction of Sox gene expression in the interdigital mesoderm is accompanied by loss of the apoptotic response to exogenous BMPs. L-Sox5 and Sox6 are respectively induced coincident and after the expression of Bmpr1b in the prechondrogenic aggregate, and their activation correlates with the induction of Type II Collagen and Aggrecan genes in the differentiating cartilages. The expression of Bmpr1b precedes the appearance of morphological changes in the prechondrogenic aggregate and establishes a landmark from which the maintenance of the expression of all Sox genes and the progress of cartilage differentiation becomes dependent on BMPs. Moreover, we show that Ventroptin precedes Noggin in the modulation of BMP activity in the developing cartilages. In summary, our findings suggest that Sox8, Sox9, and Sox10 have a cooperative function conferring chondrogenic competence to limb mesoderm in response to BMP signals. In turn, BMPs in concert with Sox9, Sox6, and L-Sox5 would be responsible for the execution and maintenance of the cartilage differentiation program.     

Zebrafish msxB, msxC and msxE function together to refine the neural-nonneural border and regulate cranial placodes and neural crest development

The zebrafish muscle segment homeobox genes msxB, msxC and msxE are expressed in partially overlapping domains in the neural crest and preplacodal ectoderm. We examined the roles of these msx genes in early development. Disrupting individual msx genes causes modest variable defects, whereas disrupting all three produces a reproducible severe phenotype, suggesting functional redundancy. Neural crest differentiation is blocked at an early stage. Preplacodal development begins normally, but placodes arising from the msx expression domain later show elevated apoptosis and are reduced in size. Cell proliferation is normal in these tissues. Unexpectedly, Msx-deficient embryos become ventralized by late gastrulation whereas misexpression of msxB dorsalizes the embryo. These effects appear to involve Distal-less (Dlx) protein activity, as loss of dlx3b and dlx4b suppresses ventralization in Msx-depleted embryos. At the same time, Msx-depletion restores normal preplacodal gene expression to dlx3b-dlx4b mutants. These data suggest that mutual antagonism between Msx and Dlx proteins achieves a balance of function required for normal preplacodal differentiation and placement of the neural-nonneural border.     

Parasites, emerging disease and wildlife conservation

In this review some emerging issues of parasite infections in wildlife, particularly in Australia, are considered. We discuss the importance of understanding parasite biodiversity in wildlife in terms of conservation, the role of wildlife as reservoirs of parasite infection, and the role of parasites within the broader context of the ecosystem. Using a number of parasite species, the value of undertaking longitudinal surveillance in natural systems using non-invasive sampling and molecular tools to characterise infectious agents is illustrated in terms of wildlife health, parasite biodiversity and ecology.     

Phylogenetic relationships among Southeast Asian climbing bamboos (Poaceae: Bambusoideae) and the Bambusa complex

A phylogenetic analysis of Bambusa and allies based on the plastid DNA non-coding regions rps16-trnQ, trnC-rpoB, trnH-psbA and trnD-T, and a partial nuclear GBSSI gene, was carried out. This included representatives from all four Bambusa subgenera (including type species), a group of segregate Southeast Asian genera distinctive by their climbing–scrambling culms (Dinochloa, Holttumochloa, Kinabaluchloa, Maclurochloa, Soejatmia, Sphaerobambos), and two other Bambusinae genera (Dendrocalamus, Gigantochloa). The results do not support the present subgeneric classification of Bambusa. The climbing Southeast Asian genera, all of which include species previously placed in Bambusa, are distinct from the “core Bambusa group” (type species and alliance) and the Bambusa complex generally.     

SNS: Adhesive properties, localization requirements and ectodomain dependence in S2 cells and embryonic myoblasts

The body wall muscles in the Drosophila larva arise from interactions between Duf/Kirre and Irregular chiasm C-roughest (IrreC-rst)-expressing founder myoblasts and sticks-and-stones (SNS)-expressing fusion competent myoblasts in the embryo. Herein, we demonstrate that SNS mediates heterotypic adhesion of S2 cells with Duf/Kirre and IrreC-rst-expressing S2 cells, and colocalizes with these proteins at points of cell contact. These properties are independent of their transmembrane and cytoplasmic domains, and are observed quite readily with GPI-anchored forms of the ectodomains. Heterotypic interactions between Duf/Kirre and SNS-expressing S2 cells occur more rapidly and to a greater extent than homotypic interactions with other Duf/Kirre-expressing cells. In addition, Duf/Kirre and SNS are present in an immunoprecipitable complex from S2 cells. In the embryo, Duf/Kirre and SNS are present at points of contact between founder and fusion competent cells. Moreover, SNS clustering on the cell surface is dependent on Duf/Kirre and/or IrreC-rst. Finally, although the cytoplasmic and transmembrane domains of SNS are expendable for interactions in culture, they are essential for fusion of embryonic myoblasts.