双酶法水解罗非鱼下脚料制备降血糖肽的工艺研究

以水解度和α-葡萄糖苷酶抑制率为评价指标,确定双酶复合水解罗非鱼下脚料的方案,并通过单因素试验和正交试验进行优化,最后得到最适酶解工艺参数为先在碱性蛋白酶在温度50℃,加酶量10000 U/g,pH值9.5,底物质量分数6%条件下水解;再在胰蛋白酶在温度37℃,加酶量10000 U/g,pH值8条件下水解100 min。此工艺条件下罗非鱼下脚料水解度、水解产物的α-葡萄糖苷酶抑制率分别为48.26%和41.46%。     

温州南部沿岸海域鱼类群落特征及其与环境因子的关系

根据2015年春季(5月)和秋季(9月)温州南部沿岸海域渔业资源调查数据,利用物种多样性指数、多元分析及其典范对应分析等方法,对该海域鱼类种类组成、多样性和群落与环境因子间的关系进行了分析。结果表明:温州南部沿岸海域共鉴定鱼类47种,隶属于9目27科41属,主要以暖水性和暖温性为主,鲈形目(Perciformes)种类最多,共26种;其次为鲱形目(Clupeiformes),共6种;再次为形目(Tetraodontiformes),共4种。春季,优势种依次为日本鳀(Engraulis japonicas)、镰鲳(Pampus echinogaster)、六丝矛尾虾虎鱼(Amblychaeturichthys hexanema)和棘头梅童鱼(Collichthys lucidus),其渔获量占总渔获量的49.3%;秋季,优势种为龙头鱼(Harpodon nehereus)、棘头梅童鱼和六指马鲅(Polynemus sextarius),占总渔获量的50.8%。日本鳀、蓝圆鲹(Decapterus maruadsi)、刺鲳(Psenopsis anomala)、龙头鱼、鳓(Ilisha elongata)和六指马鲅等是各季节各站位组的典型种及造成不同站位组间群落差异的主要分歧种。此外,组内的典型种一定程度上是组间的分歧种和群落的优势种。经Pearson分析,Margalef种类丰富度指数(D)和Shannon-Wiener多样性指数(H')与溶解氧呈极显著正相关,而与盐度和温度均呈显著正相关。通过典范对应分析(CCA)得出,影响鱼类群落的主要环境因子为酸碱度p H、水深和盐度。     

沿浦湾秋茄种植前后大型底栖动物生态位和功能群变化

基于沿浦湾2014年10月(秋季)和2016年10月(秋季)的潮间带大型底栖动物调查资料,运用生态位宽度、生态位重叠、功能群分类和冗余分析(RDA)等指标与方法,分析秋茄(Kandelia candel)种植前、后大型底栖动物的生态位、功能群变化。研究结果表明,秋茄种植后广生态位种和中生态位种物种数占比与种植前相比较均有所增加,窄生态位种物种数占比减少。种植前生态位重叠值最大的种对为大青弹涂鱼(Scartelaosgigas)和细螯虾(Leptochela gracilis)(0.94),种植后则分别为豆形拳蟹(Pyrhila pisum)和微黄镰玉螺(Lunatica gilva)(0.99)、堇拟沼螺(Assiminea violacea)和光滑河篮蛤(Potamocorbula laevis)(0.99)。种植后高、中潮带功能群多样性较种植前上升,而低潮带功能群多样性下降;种植后浮游生物食者(Pl)、植食者(Ph)和杂食者(Om)的密度较种植前均增加,而肉食者(Ca)的密度略有减少。秋茄种植前3个潮带之间无显著性差异(P0.05);秋茄种植后高潮带与低潮带,以及中潮带与低潮带均有显著性差异(P0.05)。冗余分析(RDA)得出,对大型底栖动物群落具有较大影响的因子由种植前的铅、镉和石油类变为种植后的锌、镉和砷。总之,苍南沿浦湾秋茄林种植对大型底栖动物生态位和功能群总体上具有积极的改善作用。     

Modelling the impacts of environmental variation on habitat suitability for Pacific saury in the Northwestern Pacific Ocean

We developed habitat suitability index (HSI) models for two size classes of Pacific saury Cololabis saira in the Northwestern Pacific Ocean. Environmental data, including sea surface temperature, sea surface height, salinity, and net primary production, and catch and effort data from Taiwanese distant‐water stick‐held dip net fisheries during the main fishing season (August–October) during 2002–2015 were used. Habitat preferences and suitable habitat area differed between size classes. The suitable habitat was located between 40–47.5°N and 145–165°E for large‐sized Pacific saury but encompassed a greater area (35–47°N and 140–165°E) for medium‐sized Pacific saury. Both size classes were affected by substantial interannual variation in the environmental variables, which in turn can be important in determining the potential fishing grounds. We found a significant negative relationship between the suitable habitat area and the Niño3.4 indices with a time‐lag of 6 months for the large‐sized (r = ?0.68) and medium‐sized (r = ?0.42) Pacific saury, respectively, as well as the total landings of Pacific saury by all fishing fleets (r = ?0.46). As remotely‐sensed environmental data become increasingly available, HSI models may prove useful for evaluation of possible changes in habitat suitability resulting from climate change or other environmental phenomena and in formulating scientific advice for management.     

Characterization of the monoclonal antibody specific to the ORF72 protein of koi herpesvirus and cellular distribution analysis of the viral protein

Koi herpesvirus (KHV) is an emerging pathogen of koi and common carp that causes a severe disease and mass mortality of infected fish. The KHV ORF72 protein is an important capsid protein that has been suggested to be a candidate for the development of diagnostic reagents and KHV vaccines. The purpose of this study was to clone and express the KHV ORF72 gene for further preparation of a specific monoclonal antibody (mAb) and to analyse cellular distribution of the viral protein. The mAb 3E1 could specifically recognize the expressed ORF72 protein of transfected cells by indirect immunofluorescence, and the antigenic site recognized by the mAb 3E1 was mapped to the region of N-terminal 124 residues of KHV ORF72. This mAb was further demonstrated to specifically detect the KHV-infected fish tissue by immunohistochemistry, thereby suggesting its high diagnostic potential. In addition, the cellular distribution analysis of the KHV ORF72 protein revealed that the region of amino acid residues 125–247 was related to mitochondrial localization and proliferation. Furthermore, a putative nuclear export signal (NES) of ORF72 at the residues 201–212 was confirmed on the basis of its function associated with NES activity.     

The impacts of fiscal decentralization on environmental innovation in China

Environmental innovation is the fundamental support for sustainable development. Exploiting Chinese provincial panel data from 2007 to 2017, this study investigates the impacts of fiscal decentralization on environmental innovation. In particular, we discuss the regulating role of government’s environmental protection expenditures relying on the mediator effect model. The empirical analyses show that fiscal decentralization cannot only directly promote environmental innovation, but also indirectly weaken environmental innovation through the environmental protection expenditure of the local government. The overall performance is that fiscal decentralization promotes environmental innovation. It is noteworthy that there is regional heterogeneity in the impact of fiscal decentralization on environmental innovation. The impact in the east is significantly higher than in the central and western regions in China.     

Assessment of pentachlorophenol toxicity in newborn calves: clinicopathology and tissue residues

Newborn Holstein bull calves were fed either analytical pentachlorophenol (aPCP) or technical pentachlorophenol (tPCP) for 6 wk to establish and compare the clinical and pathologic manifestations of toxicity. Four groups of three calves/group were each fed either 1 or 10 mg X (kg body weight)-1 X d-1 of either aPCP or tPCP. A fifth group served as control. Dosages of both PCP preparations were normalized to contain equal concentrations of PCP. Toxic effects were observed only at the 10 mg/kg dose in the tPCP-treated calves. These effects included decreased body weight gain, anorexia, decreased serum protein concentration, elevated serum gamma glutamyl transferase, and decreased triiodothyronine (T3) and thyroxine (T4) concentrations. Histologic lesions included cortical atrophy in the thymus and squamous metaplasia and hyperkeratous changes in the Meibomian gland of the eyelid. Thyroid function, which was assessed in vivo by measuring the rate of T3 and T4 production over 4 h after thyrotropin-releasing hormone (TRH)-challenge, was not impaired suggesting an extrathyroidal site of toxic action. Although serum chemistry indicators were suggestive of hepatic injury there were no discernable lesions. Organ weight analyses were inconclusive but there was a tendency toward enlargement of liver, kidneys and thyroid and decreased weight of lungs, spleen and thymus. A toxic effect clearly related to PCP and not its contaminants was depressed active transport of p-aminohippurate measured in kidney slices in vitro. Steady state concentrations of PCP in serum were about 40 and 90 ppm for the 1 and 10 mg/kg groups, respectively. Concentrations of PCP among the major organs were comparable.     

色氨酸水平对12～17周龄金定蛋鸭抗氧化性能影响的研究

试验旨在通过研究不同水平色氨酸对12~17周龄金定蛋鸭抗氧化指标的影响,最终确定最佳的色氨酸水平。试验采用单因素完全随机分组法,将12周龄健康的金定蛋鸭300只随机分成5组,每组设6个重复,每个重复10只。Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组饲喂的色氨酸水平依次为0.199%、0.220%、0.240%、0.260%、0.300%。采用二次曲线方程确定12~17周龄金定蛋鸭色氨酸的最佳水平。结果表明:0.250%~0.267%水平的色氨酸能显著提高试鸭血清和肝脏过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-PX)和总抗氧化能力(T-AOC)(P<0.05),显著提高试鸭肝脏超氧化物歧化酶(SOD)活性(P<0.05),但是对试鸭血清SOD活性影响不显著(P>0.05),显著降低试鸭血清和肝脏丙二醛(MDA)浓度(P<0.05)。综上,0.250%~0.267%水平的色氨酸对12~17周龄金定蛋鸭抗氧化功能具有最好的调节作用。     

Long‐term Effects of Pyrethrin and Cyfluthrin,a Type II Synthetic Pyrethroid,Insecticide Applications on Bull Reproductive Parameters

The objectives of this study were to determine effects of cyfluthrin and pyrethrin spray products, used in combination with cyfluthrin topical and ear tag applications, on bull reproductive parameters over 18 weeks. Angus or Angus x Simmental bulls were randomly assigned to one of three treatment groups: (i) no exposure to pyrethrins/cyfluthrin (CONT; n = 10), (ii) cyfluthrin ear tag and topical applications (ET; n = 10), or (iii) cyfluthrin ear tag, topical, premise spray and pyrethrin fog spray applications (ET+S; n = 8). Bull body weight was measured every 3 week, and body condition score and scrotal circumference were recorded on weeks 0, 9 and 18. Semen and serum were collected every 3 weeks for sperm evaluation and testosterone measurement, respectively. There was a treatment × week interaction (p < 0.01) for sperm with primary defects; bulls in CONT group had a greater (p = 0.01) percentage of sperm with primary defects than bulls treated with insecticides at week 18. Overall and progressive sperm motility, normal sperm morphology, secondary sperm defects and serum testosterone concentrations changed (p < 0.01) over time in all bulls; however, treatment did not affect (p ≥ 0.13) any of these parameters. There were also no treatment effects (p ≥ 0.08) on bull body weight, body condition score or scrotal circumference. The use of pyrethrin‐ and cyfluthrin‐based insecticides, regardless of application, did not negatively affect reproductive parameters in beef bulls when administered over 18 weeks.