Do summer temperatures trigger spring maturation in Pacific lamprey,Entosphenus tridentatus?     

B. J. Clemens  S. van de Wetering  J. Kaufman  R. A. Holt  C. B. Schreck 《Ecology of Freshwater Fish》2009,18(3):418-426

Abstract –  Pacific lamprey, Entosphenus tridentatus , return to streams and use somatic energy to fuel maturation. Body size decreases, the lamprey mature, spawn, and then die. We predicted that warm, summer temperatures (>20 °C) would accentuate shrinkage in body size, and expedite sexual maturation and subsequent death. We compared fish reared in the laboratory at diel fluctuating temperatures of 20–24 °C (mean = 21.8 °C) with fish reared at cooler temperatures (13.6 °C). The results confirmed our predictions. Lamprey from the warm water group showed significantly greater proportional decreases in body weight following the summer temperature treatments than fish from the cool water group. A greater proportion of warm water fish sexually matured (100%) and died (97%) the following spring than cool water fish (53% sexually mature, 61% died). Females tended to mature and die earlier than males, most obviously in the warm water group.  相似文献   

温湿度和幼虫饥饿胁迫对白僵菌毒杀甜菜夜蛾效果的影响     

崔璟辉  陈浩涛 《湖南农业科学》2012,(13):94-96

为了研究温、湿度和饥饿胁迫对白僵菌防治甜菜夜蛾幼虫的影响,进行了室内试验。结果表明:温度对白僵菌的致病力有显著影响,24～27℃下有利于白僵菌感染甜菜夜蛾幼虫;湿度对白僵菌的致病力也有显著影响,高湿环境有利于白僵菌感染甜菜夜蛾幼虫;饥饿胁迫能显著缩短甜菜夜蛾幼虫被白僵菌杀死的时间。因此,在利用白僵菌防治甜菜夜蛾幼虫时,只有充分考虑温、湿度等天气因素,害虫的食物摄取,幼虫虫龄等基本情况,才能取得最佳的防治效果。  相似文献   

莱茵衣藻氮胁迫基因数字表达谱分析     

李亚军  费小雯  邓晓东 《热带农业科学》2012,32(11):66-70

以正常培养条件下的莱茵衣藻为对照,通过数字表达谱技术对缺氮诱导3 d的藻细胞进行转录水平上的检测,并结合pathway分析。结果表明:差异表达基因共有482个,其中上调表达基因108个,下调表达基因374个;这些差异表达的基因共分布在85个pathways中。此结果为进一步揭示氮元素缺乏诱导微藻油脂积累的分子机理提供有用信息。  相似文献   

Role of Belowground Parts of Green Manure Legumes,Crotalaria spectabilis and Sesbania rostrata,in N Uptake by the Succeeding Tendergreen Mustard Plant     

《Plant Production Science》2013,16(1):116-123

Using symbiotically N₂-fixing legumes as green manures is a way to supply N from the atmosphere to cropping ecosystems. Usually whole plants of the green manure are incorporated into soil; hence, the belowground parts as well as the aboveground parts would contribute to N transfer to succeeding crops. However, little is known about the contribution of the belowground parts alone. We assessed N transfer from belowground parts compared to whole plants of two legumes, Crotalaria spectabilis and Sesbania rostrata. Each of the legumes was grown approximately for 3 months in a 1/2000a Wagner pot filled with soil media, and then the roots alone (R) or shoot and root (S + R) were harvested and incorporated in the pots. Tendergreen mustard (Brassica rapa) as the succeeding crop was grown for 66 days in these pots without additional fertilizer. Although the amount of N in green manure in S + R pots was approximately 4-fold higher than that in R pots, differences in N uptake by tendergreen mustard between the S + R and R pots were smaller (1.7-fold for C. spectabilis and 2.3-fold for S. rostrata). This means that N recovery rate by tendergreen mustard was significantly higher in R than in S + R pots with either green manures. Differences in C/N ratio of the green manures could not likely explain the higher N recovery rate in R pots. Bioassay of the aqueous extracts from the green manure with lettuce seedlings suggested that growth inhibitory effects might be responsible for the lower recovery rate in S + R treatment.  相似文献   

饥饿和重摄食对鲤鱼脂蛋白脂肪酶活性的影响     

王钦  李建林  唐永凯  李红霞  吴钧晟  张磊  沈泽恩  俞菊华 《湖南农业大学学报(自然科学版)》2019,45(1)

采用对硝基苯酚法测定正常摄食、饥饿(14 d)和重摄食(3 d)状态下鲤鱼不同组织和器官中脂肪酶及脂蛋白脂肪酶(lipoproteinlipase,LPL)的活性。结果显示:与正常摄食相比,饥饿鲤鱼肌肉、脂肪和心脏中脂肪酶比活力显著下降(P0.05),但脂肪和心脏中LPL比活力显著升高(P0.05);除脂肪中LPL外,重摄食3d的鲤鱼各组织和器官中脂肪酶和LPL比活力比正常摄食和饥饿鲤鱼均显著升高(P0.05),有明显的补偿作用。  相似文献   

饥饿和光照对鳙仔鱼耳石沉积和日轮形成的影响     

解玉浩  李勃 《大连水产学院学报》1999,14(3):1-6

用同１尾雌鱼催产孵出的鳙鱼仔鱼进行了饥饿、光照对耳石沉积和日轮形成影响的实验研究。结果表明,仔鱼全长生长饥饿组慢于对照组,差异极显,ＤＤ组、ＬＬ组与对照组相接近,无显差异。耳石直径各实验组与对照组无显差异。饥饿组仔鱼在体长生长停止的情况下耳石仍能继续沉积。仔鱼孵出后第２ｄ形成第１轮,之后每天１轮,对照组１６日龄仔鱼耳石上有１５个日轮。饥饿组约９０％的个体烽比对照组少２０％,约１０％的个体耳石  相似文献   

Proteomics analysis of mitochondrial extract from liver of female zebrafish undergoing starvation and refeeding     

Y.‐L. ENYU  A.C. SHU‐CHIEN 《Aquaculture Nutrition》2011,17(2):e413-e423

Many fish species can withstand long period of food deprivation and consequently compensate for any weight loss by undergoing rapid growth during resumption of feeding. There is an interest in taking advantage of compensatory growth to reduce feed cost. In this present study, we attempted to compare the changes in hepatic mitochondrial proteome of zebrafish undergoing starvation and refeeding. Two‐dimensional gel separation and image analysis revealed a total of 65 spots that showed changes in expression after 15 days of starvation followed by 7 days of refeeding. A total of 35 proteins were selected for mass spectrometry analysis, resulting in the positive identification of 18 proteins. Identified proteins indicated that starvation resulted in reduction in glycolysis and increase in gluconeogenesis, while refeeding caused these activities to return to normal levels. Expression pattern of several proteins related to fatty acid and amino acid metabolism also suggested the utilization of non‐carbohydrate resources for energy during starving conditions. Proteins with chaperoning and antioxidative roles such as glucose‐regulated protein, paraxonase and heat‐shock protein were also upregulated in starved conditions.  相似文献   

氮饥饿与磷饥饿促使缺刻缘绿藻花生四烯酸含量增加的比较   总被引：5，自引：2，他引：3  

童牧  于水燕  欧阳珑玲  周志刚 《水产学报》2011,35(5):763-773

以富含花生四烯酸(AA)的缺刻缘绿藻H4301为研究对象,探讨了不同光照强度条件下氮饥饿与磷饥饿对藻生物量、AA及脂肪酸含量变化的影响。发现氮饥饿与磷饥饿均降低了藻类的生长速率与生物量,当在60 μmol photons/(m²·s)的低光照强度下,磷饥饿时的藻类平均生长速率最低［0.025 g/(d·L)］,不足BG-11完全培养基中该藻生长速率的一半;氮饥饿与磷饥饿均能提高藻细胞总脂肪酸及AA的含量,但在低光照强度下磷饥饿的促进效果比较差;无论是完全培养基中还是饥饿处理时,200 μmol photons/(m²·s)的高光照强度都不利于藻细胞AA及多不饱和脂肪酸的合成与积累;随着饥饿时间的不断持续,AA占总脂肪酸的百分含量逐渐增加,而亚油酸的百分含量逐渐降低,但在磷饥饿时,油酸的百分含量也增加,特别在高光照强度下,以油酸为主的单不饱和脂肪酸含量在第27天时占细胞干重的5.28%,以致AA含量的增加没有氮饥饿时的显著。从脂肪酸成分的变化来分析,该藻在氮或磷饥饿过程中主要是从亚油酸到γ-亚麻酸再到20∶3ω6这个途径来合成并积累AA,其中Δ6去饱和酶是限速酶,而ω3去饱和酶催化步骤受饥饿处理的负调控对确保AA的合成与积累有较大的积极作用。氮饥饿使藻细胞蛋白质合成受阻以及磷饥饿使核酸合成、糖类与能量代谢产生障碍,从而阻止藻类的生长并迫使细胞代谢流转向不含氮和磷的脂肪酸合成代谢,以提高藻细胞总脂肪酸及AA含量。  相似文献   

饥饿对褐菖鲉消化道指数及消化酶活力的影响   总被引：1，自引：0，他引：1  

江丽华  朱爱意  苑淑宾 《水产科学》2011,30(4):187-191

在水温(18±0.5)℃、盐度27.0±0.5条件下,测定了褐菖鲉不同饥饿时间(0、3、7、14、21 d)的比肝质量、比胃质量、比幽门质量、比肠长及各消化组织消化酶活力。试验结果表明,在饥饿过程中,褐菖鲉消化道组织萎缩,比肝质量、比胃质量、比幽门质量和比肠长呈显著下降趋势(P<0.01),其中比肝质量下降速率最大,饥饿21 d的比肝质量比对照组下降85.033%。饥饿期间,蛋白酶活力总体呈先升后降的趋势,差异显著(P<0.05)。淀粉酶活力的变化趋势亦为先升后降,饥饿1 d,前、中、后肠、幽门的淀粉酶活力呈不同程度上升,之后,除胃和幽门外,随着饥饿时间的延长,皆呈下降趋势,与对照组相比,差异显著(P<0.05);脂肪酶活力总体呈缓慢下降趋势,差异不显著(P>0.05)。  相似文献   

饥饿胁迫对虾夷扇贝几种免疫因子的影响   总被引：2，自引：0，他引：2  

李石磊  李文姬  付成东  于佐安  滕炜鸣  刘忠颖 《水产科学》2011,30(8):441-444

在(17±1)℃条件下,研究了壳长(8.83±0.52)cm的虾夷扇贝在不同饥饿时间(5、10、15、20、30 d)处理后,血液中血细胞总数、血细胞吞噬水平、酸性磷酸酶、过氧化物歧化酶的变化。结果表明,扇贝的血细胞总数随着饥饿时间的延长逐渐降低,饥饿20 d以上的扇贝血细胞数明显降低,与投喂组差异极显著(P<0.01),扇贝血细胞吞噬率和酸性磷酸酶活性呈现出先小幅上升后下降的趋势,饥饿253、0 d与投喂组差异显著(P<0.05),饥饿253、0 d的扇贝过氧化物歧化酶的活性有所升高,饥饿30d,与投喂组差异显著(P<0.05)。试验表明,饥饿超过20 d,扇贝的免疫系统受到较为严重的破坏。  相似文献