发病鲆鲽类分离菌株的16S rRNA基因测序分析

细菌性疾病是中国海水养殖鲆鲽类的主要病害,为全面了解病原菌种类,本研究对1999~2012年从山东、江苏、河北、天津等沿海地区养殖场发病鲆鲽鱼类中分离得到的124株优势菌株进行了16S rRNA基因测序和系统发育学分析。将基因序列与GenBank核酸序列数据库进行相似度比对分析,结果显示,有83株与弧菌属(Vibriosp.)细菌相似度最高,11株与气单胞菌属(Aeromonas sp.)细菌相似度最高,4株与爱德华氏菌属(Edwardsiella sp.)细菌相似度最高,26株为其他15种属的细菌。根据系统发育学分析结果,进一步将66株菌鉴定为16个种,优势种为溶藻弧菌(V.alginolyticus)、哈氏弧菌(V.harveyi)、鳗弧菌(V.anguillarum)、杀鲑气单胞菌(A.salmonicida)和迟缓爱德华氏菌(E.tarda)。选择其中的9株鳗弧菌和4株迟缓爱德华氏菌进行人工感染实验,结果显示,其中7株鳗弧菌和3株迟缓爱德华氏菌对大菱鲆(Scophthalmus maximus)有较强的致病性。研究结果可为阐明中国海水养殖鲆鲽类的流行病发生历史、病原种类、病原监测及疾病控制提供重要参考。     

不同产地鲍鱼特征元素分析与主成分评价模型的建立

为了找出不同产地鲍鱼(Haliotis Spp.Abalone)的区域性差异,并探究一种有效的鲍鱼产地的鉴别方法,采用主成分分析法对对广东、福建、山东、辽宁4个主要养殖省份鲍鱼样品肌肉中的特征元素(Na、K、Mg、Ca、Fe、Zn、Cu、Ni、As、Al、Mn、Cr、Se)进行分析。结果显示,鲍鱼样品的元素含量存在差异,Mn的变异程度最大,变异系数为74%,Ni次之,为65%,其次是Se (60%),其余元素的变异系数均高于10%。同时,通过对这些数据进行降维处理,有效地从13个特征元素中提取了6个元素作为主成分,累计方差贡献率达89.87%;同时发现Ca、Se、Na、Fe、Mn、K、Ni这7种元素是不同产地鲍鱼的特征元素,并建立了主成分综合评价模型:F=0.2777F_1+0.2652F_2+0.1295F_3+0.1066F_4+0.0656F_5+0.0541F_6。模型的建立可以为利用特征元素对不同产地鲍鱼的产地溯源提供一定的理论参考。     

1976-2006年江苏省气温和降水量的时空变化特征

气候变化的时空差异及其发展趋势是我国生态环境变化的重要驱动因子。通过获取江苏省13个气象站点1976—2006年气象资料,应用空间插值、线性趋势法、滑动平均法、Mann-Kendall 非参数检验、滑动t-检验和小波变换等方法对江苏省气温和降水量进行线性趋势分析、平滑预测分析、突变分析和周期性分析,揭示该地区气候时空差异和变化发展趋势。结果表明：1976—2006年,苏北、苏中和苏南地区平均气温、平均最高气温和平均最低气温呈现波动上升趋势,且多在20世纪90年代发生突变现象,呈现明显上升趋势,在25～32 a、15～25 a和10～15 a的三类时间尺度上存在着比较稳定的周期变化规律;降水量均波动起伏较大,无明显的增减现象,且在1990—2000年间以正距平为主;年降水量多在20世纪70年代末和本世纪初发生突变;降水量在25～32 a、15～25 a和10～15 a的三类时间尺度上存在着明显的周期性变化。通过上述研究,有助于科学认识气候变化规律,积极应对区域气候变化,保障江苏省生态稳定及促进社会经济发展。     

鲁西牛生长发育规律研究

[目的]为进一步了解鲁西牛生长发育规律及体重与各体尺间的内在联系。[方法]研究利用SPSS 26.0软件,分析鲁西牛体重与各体尺性状间的相关性,建立各体尺性状对体重的最优回归模型。[结果]结果显示鲁西牛群体I中所有体尺性状均与体重间存在极显著正相关(P<0.01),其中腹围(X5)、体高(X1)和胸围(X3)通过较强的直接作用影响体重(Y)。鲁西牛体尺(X)对体重(Y)的最优回归模型为：Y=2.374X1+2.455X3+2.721X5-923.527 (R=0.955,P<0.01)。根据最优回归模型,对鲁西牛群体II的体重数据进行预测,并将群体I和群体II进行合并为群体III,分析鲁西牛群体III体重与体高(X1)、胸围(X3)和腹围(X5)的相关性,并对相关系数进行分解。结果显示,体重(Y)相关程度最高的胸围(X3)性状对体重的直接作用最大(P=0.939),与体重间相关系数最小的体高(X1)则是通过较强的间接作用影响体重。[结论]综上,体高、胸围和腹围可作为3个重要参考指标,为后续合理评估鲁西牛生长发育性能提供理论参考。     

禽腺联病毒全基因组的克隆及感染性病毒的拯救

为了克隆禽腺联病毒(Avian adeno-associated virus,AAAV)全基因组用于构建基因转移载体研究,以鸡胚致死孤儿病毒(CELO)作为辅助病毒与AAAV共接种SPF鸡胚进行AAAV的增殖,将AAAV约4.7kb双链基因组DNA与pCR2.1载体连接,构建了含AAAV全基因组的重组质粒pAAAV并进行了测序。序列分析表明,AAAV YZ-1株的基因组为4684bp,两端具有141bp的末端倒置重复序列和Rep蛋白结合位点特征序列,与GenBank中收录的AAAV DA-1株和VR-865株的核苷酸序列同源性分别为95.0%和92.2%。将pAAAV质粒转染CELO病毒感染的鸡胚肝细胞系,获得了感染性AAAV病毒粒子,结果证明克隆的AAAV基因组中存在与病毒复制和包装相关的正确关键序列,可用于重组AAAV载体的构建。     

拉萨河流域非点源污染输出风险评估

有效识别流域非点源污染高风险区,对污染控制与管理以及水环境质量改善具有重要意义。该研究以拉萨河流域为研究对象,构建包括降雨、地形和施肥影响因子的输出风险模型,识别流域各级非点源污染输出风险的地域单元。结果表明:1996年和2010年,非点源污染输出风险概率分别为50.0%和46.3%;非点源污染风险处于较高以上程度的区域面积分别为12 985.8和11 628.0 km2,占全区总面积的38.9%和34.9%;与1996年相比,2010年非点源污染风险程度由低级别向高级别转换的总面积约为6 674.3 km2。拉萨河流域非点源污染发生的风险概率为中等,风险程度在局部范围内有所下降,主要表现在高风险区域面积减少、低风险区域面积增加,但是中等和较高风险区域面积有增加趋势。土地利用变化、农业生产和水土流失是非点源污染发生的主要原因,应巩固生态环境综合治理成果,提前应对可能出现的非点源污染问题,制定生态农业发展规划,营造控制非点源污染迁移的植被缓冲带。     

Ecological consequences of invasive lake trout on river otters in Yellowstone National Park

The introduction of lake trout (Salvelinus namaycush) to Yellowstone Lake in Yellowstone National Park has contributed to a significant decline in the endangered Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri), leading to concern over the persistence of this subspecies but also to piscivorous predators in this community. We assessed the impact of lake trout on a key piscivore, the river otter (Lontra canadensis) in two lakes in Yellowstone National Park. Yellowstone Lake continues to support a native cutthroat trout population, although the recent introduction of lake trout has dramatically impacted the cutthroat trout population. Nearby Lewis Lake has an entirely introduced fish fauna of lake trout, brown trout (Salmo trutta), and Utah chub (Gilia atraria) but lacks cutthroat trout. Analysis of otter scat from Yellowstone Lake implicated trout (lake or cutthroat trout) as a major prey item (57% of scat), whereas stable isotopes identified longnose suckers (Catostomus catostomus) as the primary prey there (58% of diet). By contrast, scat from Lewis Lake implicated minnows, presumably Utah chub, as the primary prey for otters occupying that lake (86%), while stable isotopes implicated brown trout (64%) over both lake trout and Utah chub (36% combined). Our data establish the importance of alternative prey to otters and suggest that lake trout-induced reductions in cutthroat trout may not be catastrophic for otter populations here. These data do not necessarily exonerate lake trout, as their impact on other species, most notably grizzly bears (Ursus arctos) and piscivorous birds, has been documented to be substantial, and further data on the nutritional value of alternate prey are required to confirm or refute a working hypothesis that otter populations will continue to thrive in the face of the lake trout invasion.     

基于主成分分析法的福建省资源环境承载力空间差异研究

基于主成分分析法,利用SPSS19．0软件对福建省的资源环境承载力进行了研究分析。结果表明：从总体上看,沿海地区资源环境承载力综合得分大于内陆地区,但沿海地区内部差异较大,其中,厦漳泉地区以及福州地区资源环境承载力明显高于其它地区。为了促进经济社会的可持续发展,必须充分合理地利用资源环境。     

Response of confection sunflower (Helianthus annuus L.) grown in a semi‐arid environment to planting date and early termination of irrigation

Adjustments on planting date and on the time to terminate irrigation may reduce agricultural water use. However, such management practices in regions with extreme weather conditions have the potential to negatively affect yield. A 3‐year (2012–2014) study was conducted on a clay‐loam soil in a cool, semi‐arid environment to (i) determine the response of confection sunflower to planting date and irrigation termination timing and (ii) identify the relative importance of yield components in irrigated confection sunflower across planting dates. Early May planting had considerable negative effects on all studied variables, except on the percentage of large seeds. The highest yield of total and large seeds was obtained from the late May plantings, averaging 3,777 and 3,379 kg/ha, respectively. None of the irrigation strategies affected the measured variables. However, the interaction between planting date and termination of irrigation significantly affected the 1,000‐seed weight. Our study revealed the last week of May as suitable planting period for confection sunflower in the semi‐arid north‐western region of Wyoming, USA, and that irrigation on heavy soils may be terminated as early as at R5.5 stage without a significant yield reduction. The path‐coefficient analysis indicated head diameter and the number of seeds per head as important traits that significantly influence the yield of confection sunflower across planting dates.     

Waxy durum acts as a unique form of crumb softener in bread

Flour milled from waxy durum grain was incorporated into bread formulations and its effects on crumb softness and loaf volume compared to those of added fats and emulsifiers. Waxy durum had a small effect on increasing loaf volume, and little of this effect could be explained by dough height or oven spring; effects of most other additives were closely related to dough height or oven spring. For all additives, the relationship between crumb softness and loaf volume fitted a power law relationship. Waxy durum and some of the additives had a greater softening effect than predicted from their effect on volume while others produced a much firmer crumb. With only one exception, when combined with other additives waxy durum reduced compression of the crumb more than predicted on the basis of the effects on loaf volume of the additives alone. In common with some of the added lipids, during compression analysis, crumb prepared with waxy durum flour had similar levels of structural damage as crumb baked from the standard formulation; other lipids and emulsifiers produced more fragile crumb. Waxy durum flour appears to have unique effects on crumb softness.