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1.
瓦氏黄颡鱼不同季节鱼体的化学组成及能量密度预测模型   总被引:18,自引:0,他引:18  
王军辉  谢小军 《生态学报》2003,23(1):122-129
以三峡库区即将淹没的嘉陵江下游 段瓦氏黄颡鱼(Pelteobagrus vachelli)的成鱼群体为实验对象,于2000年12月至2001年10月期间,分冬、春,、繁殖期、繁殖后、秋季5个时间共采集到标本114尾(体重变幅为47.60-165.30g)。其中冬、春、繁殖后、秋季分别采集雌、雄性标本各10尾;繁殖期的雌性标本为14尾,雄性20尾。测定了这10个样本的鱼化化学组成,估算了其能量密度,并对鱼体的化学组成与能量密度进行了相关分析,以期为三峡工程截流后鱼类种群变动的对比研究提供基础资料。实验结果表明:各时期样本能量密度均分别与干物质含量和脂肪含量呈显著的直线相关关系,冬季雌性和秋季雄怀样本的能量密度与蛋白质含量之间的负相关关系达到显著性,繁殖后雌性样本及春季、繁殖期、繁殖后和秋季雄性标本的能量密度与灰分含量也呈显著的负相关关系。通过对10个样本各自的能量密度(kJ/g)分别与其干物质含量(D,%B.W.)的直线回归主程的协方差分析(ANCOVA),可将雄性5个样本的回归方程合并为一个公共方程作为预测雄性鱼体能量密度(EA)的模型:EA=-4.33 0.408D,将雌性冬季、春季、繁殖后及秋季的4个回归方程合并为一个公共方程作为预测雌性鱼体非繁殖期的能量密度(EB)的模型;EB=-3.09 0.395D,而雌性繁殖期的能量密度(EC)的预测模型为:EC=-3.16 0.381D。通过讨论发现,该种鱼的脂肪含量占体重的变幅为8.72%-14.3%(B.W),占其干物质含量的变幅为30.5%-43.7%(D.W)。高于文献报道的大多数鱼类的相应的脂肪含量。  相似文献   

2.
井冈山自然保护区12种常见灌木生物量的估测模型   总被引:7,自引:0,他引:7       下载免费PDF全文
灌木生物量模型是估测灌木生物量的重要方法之一。以井冈山自然保护区林下12种常见灌木为研究对象,根据树高(H)和地径(D)两个形态因子作为变量,进行回归分析构建模型。通过对比判别系数R 2的大小,筛选最佳生物量估测模型。方程W=a+b X12 X2、W=a+b X+c X 2和W=a X b在模拟生物量时相关指数均较高,为0.904-0.991,达到极显著水平,可用于实际生物量估测,而方程W=a+b X、W=a+b X1+c X2和W=a+b ln X在模拟灌木生物量时结果较差。利用此类方法建立的生物量模型,精度高,简便易行,对以后估算井冈山自然保护区灌木生物量和碳储量具有十分重要的意义。  相似文献   

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室内研究了体重和温度对黄鳝最大摄食率的影响。在水温相同(20℃)的条件下,随着体重的增加(4.77-144.65 g),黄鳝最大摄食量增加,但最大摄食率呈下降的趋势,两者与体重的相关关系分别为Cmax(g/d•per fish)=5.86×10-2W0.46和RLmax(J/g•d)=611.74W-0.54。初始体重(13-21g)对黄鳝最大摄食率没有显著影响(p>0.05),水温(11-38℃)对黄鳝最大摄食率的影响非常明显(p<0.01),最大摄食率和水温的回归方程为:RLmax(J/g•d)=418.56-80.78t+4.73t2-0.074t3。黄鳝的最佳食欲温度为30.8℃,此时最大摄食率为255.46J/g•d。试验发现,南京地区的黄鳝最低摄食温度为8℃。采用方程RLmax(J/g•d)=(1526.49-294.60t+17.25t2-0.27t3)W-0.54能够预测黄鳝在不同体重和不同温度条件下的最大摄食率。  相似文献   

4.
湾鳄采食量活动性季节变化与环境温度的关系   总被引:3,自引:0,他引:3  
湾鳄是外热动物,其采食量及活动规律受环境温度的影响极为明显,呈现苏醒期、发情期、产蛋繁殖期(盛食期),越冬准确期,越冬期等季节性周期现象。越冬期人工保温,是提高湾鳄成活率的关键。  相似文献   

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【目的】评价日粮中不同水平亮氨酸对繁殖期意大利蜜蜂Apis mellifera ligustica蜂群群势及工蜂发育的影响。【方法】选取重庆荣昌本地繁殖期意大利蜜蜂21群,随机分为7组,分别饲喂添加0,15.30,17.50,26.25,35.00,43.75和52.5 g/kg亮氨酸的试验日粮,每12 d测定各组蜂群群势、封盖子量、蜂群取食量和营造王台情况,24 d后测定蜂群采集行为、工蜂初生重、工蜂虫体蛋白质含量及工蜂寿命。【结果】当亮氨酸添加水平为43.75和52.50 g/kg时能够显著提高繁殖期意大利蜜蜂的蜂群群势、封盖子量、蜂群取食量及采集行为(P0.05)。与空白对照组相比,基础日粮组及各亮氨酸添加组的新出房蜂和6日龄幼虫体蛋白质含量较高(P0.05);各亮氨酸添加组的工蜂初生重显著高于空白组(P0.05);不同亮氨酸添加水平对意大利蜜蜂工蜂寿命影响较小。此外,亮氨酸添加水平26.25,35.00和43.75 g/kg能够在饲喂0-24 d时促进蜂群营造自然王台,刺激蜂群分蜂。【结论】配方日粮中43.75和52.5 g/kg的亮氨酸能够显著促进繁殖期意大利蜜蜂蜂群发展,其中43.75 g/kg的亮氨酸饲喂量还能刺激蜂群营造自然王台,激发蜂群分蜂。  相似文献   

6.
大鳍鳠鱼体能量密度及其预测模型   总被引:9,自引:1,他引:8  
于2000年11月至2001年10月由嘉陵江收集野生大鳍鳠成鱼100尾,其中冬季(12月)、春季(3月)、繁殖前(6月)、繁殖后(8月)、秋季(10月)雌雄各10尾。测定了这10个样本的鱼体能量密度及生化组成。统计分析结果表明:鱼体各生化成分含量,能量密度的性别间差异在各个季度均不显。在雌性群体中,秋季样本的蛋白质含量(16.23%),脂肪含量(5.84%),干物质含量(26.67%)和能量密度(6.14kJ/g)显高于其余各样本的相应指标。春季样本中鱼体脂肪含量和能量密度最低(2.39%,4.55kJ/g)。在雄性群体中,秋季样本的蛋白质含量(16.34%)与能量密度(5.85kJ/g)最高;春季样本中脂肪含量(1.3l%)、干物质含量(22.49%)、能量密度(4.16k.J/g)最低。各样本能量密度均分别与干物质和脂肪含量呈显的直线相关关系。通过协方差分析,将雌性群体中冬季、春季、秋季以及繁殖后样本共4个样本的能量密度与干物质含量的公共回归方程作为以干物质含量(D)预测大鳍鳠雌性群体在非繁殖期能量密度(E)的预测模型:E=-5.573 0.437D;将繁殖前雌性样本的能量密度与干物质含量的回归方程作为预测大鳍鳠雌性群体在繁殖期的能量密度的预测模型:E=-0.605 0.250D;将冬季、春季、秋季以及繁殖后雄性4个样本的能量密度与干物质含量的公共回归方程作为预测大鳍鳠雄性群体在非繁殖期的能量密度的预测模型:E=-6.046 0.456D;将繁殖前雄性样本的能量密度与干物质含量回归方程作为预测大鳍鳠雄性群体在繁殖期的能量密度的预测模型:E=-3.64 0.366D。  相似文献   

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Regulatory T (Treg) cells are a subpopulation of T cells that not only prevent autoimmunity, but also control a wide range of T cell-dependent immune responses. Glucocorticoid treatment (dexamethasone, or Dex) has been reported to amplify IL-2-mediated selective in vivo expansion of Treg cells. We simultaneously administered Dex and IL-2 to the donor in a murine allogeneic lymphocyte transplantation model to expand functional suppressive CD4+CD25+FOXP3+ T cells in the graft and to raise the regulatory T cell/effector T cell (Treg/ Teff) ratio to prevent graft-versus-host disease (GVHD). After combined treatment of the donor with Dex (5 mg/kg/day) and IL-2 (300,000 IU/mouse/day) for 3 days, grafts were subjected to flow cytometric analysis, and transplantation was carried out from male C57BL/6 mice to female BALB/c mice aged 8-12 weeks. Results showed that short-term simultaneous administration of Dex and IL-2 markedly expanded functional suppressive CD4+CD25+FOXP3+ T cells in the murine spleen. In this murine allogeneic transplantation model, the grafts from donors with Dex and IL-2 pre-treatment led to a longer survival time for the recipients than for the control group (median survival time 〉 60 day vs. 12 day, P = 0.0002). The ratio of Treg/Teff also increased remarkably (0.43 ±0.15 vs. 0.14 ± 0.01, P = 0.01). This study demonstrated that co-stimulation with Dex and IL-2 selectively expanded functional CD4+CD25+FOXP3+ T cells in vivo, and that grafts from donors pre-treated with Dex and IL-2 led to longer survival time and greater suppression of GVHD after allogeneic transplantation. Thus, GVHD can be suppressed by the specific expansion of regulatory T cells with Dex and IL-2 in graft donors.  相似文献   

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目的: 观察健康志愿者不同功率递增速率完成症状限制性极限心肺运动试验(CPET)对CPET峰值运动相关核心指标的影响,及运动中呼吸交换率(RER)的变化。以探讨不同功率递增速率对CPET峰值运动相关指标的影响。方法: 选择12名健康志愿者在一周内不同工作天随机完成中等适度程度(30 W/min)及比较低(10 W/min)和比较高(60 W/min)3种不同功率递增速率CPET。按标准方法比较CPET数据主要峰值运动核心指标:峰值运动时的摄氧量、二氧化碳排出量、负荷功率、呼吸频率、潮气量、分钟通气量、心率、血压和氧脉搏,运动持续时间和CPET各时段的RER。对三组不同功率递增速率下各个指标的差异进行组间两两比较。结果: 与中等适度功率递增速率组比较,比较低和比较高功率递增速率组的峰值功率分别显著地降低和升高((162.04±41.59)W/min vs (132.92±34.55) W/min vs (197.42±46.14) W/min, P<0.01);运动时间显著延长和缩短((5.69±1.33) min vs (13.49±3.43) min vs (3.56±0.76) min,P<0.01);峰值RER(1.27±0.07 vs 1.18±0.06 vs 1.33±0.08,P<0.01~P<0.05)与恢复期RER最大值(1.72±0.16 vs 1.61±0.11 vs 1.81±0.14,P<0.01~P<0.05)均显著降低和升高。结论: 不同功率递增速率CPET显著改变峰值运动时的功率、运动持续时间、峰值RER和恢复期最大RER。CPET规范化操作要选择个体化适合受试者的中等适度功率递增速率,而且也不能以某一固定的RER值作为保证安全、受试者达到极限运动和提前终止运动的依据。  相似文献   

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目的:在参考Davis等建立的侧脑室注射(ICV)法的基础上,建立鸡ICV法。方法:利用改建的鸡ICV法研究梯度注射神经肽Y(NPY,2.5p.g/bird和5μg/bird)对鸡采食量的影响。结果:ICV套管安装手术的成功率为88%(37/42),注射成功率为64%(23/36);NPY可显著提高注射后1~4h和24h鸡的采食量(P〈0.05),提高幅度在6.88%(5μg/bird,注射后24h)-138.95%(注射后1h)之间,注射后3h内,采食量随注射剂量增加而增加。结论:本研究建立的鸡ICV注射法是适用的,NPY是鸡重要的诱食因子之一,利用建立的ICV法,2.5μg/bird的外源性NPY就足以使鸡产生采食反应,为今后进一步开展鸡行为学研究提供方法和依据。  相似文献   

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目的以SD大鼠为模型,观察孕前炔雌醇(ethinyl estradiol,EE)暴露对子代糖代谢变化和肝脏内与糖代谢相关基因表达的影响。方法 52只雌性大鼠随机分为4组:对照组(芝麻油)、50、200、800μg/kg EE组,每天1次,连续灌胃暴露15 d后受孕。在子代出生后第23天(postnatal day,P23)和P25分别进行口服葡萄糖耐量(OGTT)和胰岛素耐量(ITT)实验,并用RT-PCR检测肝脏中糖代谢相关基因表达水平。结果子代雌鼠OGTT:200μg/kg EE组空腹血糖值显著低于对照组(P0.05);800μg/kg EE组第15min血糖值显著高于对照组、50、200μg/kg EE组(P0.01,P0.01,P0.01),50、800μg/kg EE组2 h血糖值显著低于对照组(P0.05,P0.01)。子代雄鼠OGTT:在第15 min,800μg/kg EE组血糖值显著高于对照组(P0.01);第30 min时,200μg/kg EE组血糖值显著低于对照组(P0.05)。子代雌鼠ITT:第15 min时,50、200μg/kg EE组血糖值显著高于对照组(P0.001,P0.01)。子代雄鼠ITT:第30 min时50、200μg/kg EE组血糖值显著高于对照组(P0.01,P0.01)。子代雌鼠RT-PCR:50,200μg/kg EE和800μg/kg EE组Glut2和Lpk mRNA表达水平显著低于对照组(P0.01,P0.05,P0.05);50、200μg/kg EE组Gys2 mRNA表达水平显著低于对照组(P0.01,P0.01)。子代雄鼠RT-PCR:200μg/kg EE组G6pase和Pepck mRNA表达水平显著高于对照组(P0.01,P0.01),50μg/kg EE组Glut2 mRNA表达水平相对于对照组显著降低(P0.01),800μg/kg EE组Gys2 mRNA表达水平显著高于对照组(P0.01)。结论孕前炔雌醇暴露会导致子代雌鼠葡萄糖耐量受损、子代出现胰岛素抵抗及肝脏内糖代谢相关基因表达异常。而且这些效应具有性别差异,子代雌鼠对孕前EE暴露更敏感。  相似文献   

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Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.  相似文献   

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Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.  相似文献   

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Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.  相似文献   

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正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases  相似文献   

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