漂白粉蓄积对日本蟳4种组织超微结构的影响

根据急性毒性试验确定了漂白粉对日本蟳的安全质量浓度为0．6mg／L，采用透射电镜技术研究了该质量浓度下漂白粉蓄积对日本蟳4种组织细胞(肌肉、鳃、肝胰脏和心脏)超微结构的影响。试验结果表明：漂白粉主要损伤日本蟳的鳃和肝胰脏，其次是心脏，肌肉基本无损害。鳃细胞的损害表现为鳃丝水肿，细胞器溶解，角质层变薄，线粒体、内质网的肿胀、解体；肝胰脏细胞的主要损害特征为肝管微绒毛减少、线粒体水肿解体、内质网扩张、细胞核空泡化、核膜水肿、脂肪滴增加；心脏细胞的毒理变化为线粒体内嵴肿胀、瓦解，肌原纤维不规则，内质网溶解。安全质量浓度的漂白粉经16d蓄积后，虽没有导致日本蟳死亡，但已对其体内的鳃、肝胰脏、心脏等组织细胞的超微结构产生了不同程度的影响。     

Spatially explicit fisheries simulation models for policy evaluation

This paper deals with the design of modelling tools suitable for investigating the consequences of alternative policies on the dynamics of resources and fisheries, such as the evaluation of marine protected areas (MPA). We first review the numerous models that have been developed for this purpose, and compare them from several standpoints: population modelling, exploitation modelling and management measure modelling. We then present a generic fisheries simulation model, Integration of Spatial Information for FISHeries simulation (ISIS‐Fish). This spatially explicit model allows quantitative policy screening for fisheries with mixed‐species harvests. It may be used to investigate the effects of combined management scenarios including a variety of policies: total allowable catch (TAC), licenses, gear restrictions, MPA, etc. Fisher's response to management may be accounted for by means of decision rules conditioned on population and exploitation parameters. An application to a simple example illustrates the relevance of this kind of tool for policy screening, particularly in the case of mixed fisheries. Finally, the reviewed models and ISIS‐Fish are discussed and confronted in the light of the underlying assumptions and model objectives. In the light of this discussion, we identify desirable features for fisheries simulation models aimed at policy evaluation, and particularly MPA evaluation.     

Numerical modeling of chaotic behavior for small-scale movements of demersal fishes in coastal water

ABSTRACT:   The presented model involves the application of chaos theory to generate fish movements resulting from environmental stimuli. The model uses three steps within a model neural network such as input stimuli, central decision making and response output resulting in fish movements. The stimuli in the first step include the main abiotic and biotic factors, which could be quantified as an intensity parameter that was then normalized as a ratio between 0 and 1. The decision-making process can be generated using chaos dynamics with the stimuli parameters. The response of fish movements from the output signal representing movement speed and direction of fish can be re-regulated as main movement pattern depending on physiological state or life cycle by third response filtering. The simulation results seen as a movement pattern for sea bream and flounder using this neural chaotic model fitted very well to the observations of fish tracked in the sea by ultrasonic tracking methods. It was also revealed that the fish movement components generated as movement velocity and direction when in tidal flow had similar patterns to those patterns seen in field observations with similar irregular and chaotic variations with time.     

Estimation of flow in a rearing tank of marine fish larvae by simplified numerical computation—a case of two-dimensional flow

Marine fish larvae are fragile against physical stress. However, few studies have been conducted to evaluate the flow field in a rearing tank, which is assumed to provide a high degree of physical stress to marine fish larvae. The flow field in a rearing tank (volume of 1 m³) is generated by aerators, which are commonly used to provide oxygen.

This paper is a report on the estimation of stationary flow in the rearing tank of marine fish larvae. The larvae are seven band grouper larvae of Epinephelus septemfasciatus, which have a very low survival rate immediately after the hatching of eggs. The experiments of rearing of seven band grouper larvae were carried out using rearing tanks with four aeration rates (1000, 200, 50 ml/min, and no aeration). The effects of aeration on the survival and floating death of seven band grouper larvae were examined. The experiments confirmed that the mass mortality of seven band grouper larvae depends on the flow rate in the rearing tank. Aeration at 200 ml/min resulted in the highest survival and growth rates of grouper larvae.

Larvae-rearing experiments provided evidence that the flow rates of the rearing tanks are very important design aspects of rearing tanks. The estimation of flow in a rearing tank for an aerating rate of 200 ml/min was carried out by numerical calculation. The computation was simplified by a two-dimensional flow based on experimental results. The calculated flow in the rearing tank was compared with the experimental one. The calculation of the stationary flow in the rearing tank showed good qualitative and quantitative agreement with the experimental results. The numerical estimation of the flow in a rearing tank of marine fish larvae was confirmed to be effective and satisfactory for the design of a tank that would provide optimum performance.     

不同施肥水平对杂交水稻氮、磷、钾吸收积累的影响

为探索不同施肥量下2个杂交水稻植株氮、磷、钾的吸收积累特性,采用田间小区试验研究了两个杂交稻品种抽穗期和成熟期的植株氮、磷、钾吸收积累。结果表明,2个杂交水稻品种在不同施肥水平下,抽穗期和成熟期茎＋叶鞘、叶、穗各器官内的氮、磷、钾的含量无显著差异;抽穗期,叶的氮含量最高,茎＋叶鞘的磷、钾含量最高;成熟期,叶的氮含量、茎＋叶鞘的磷含量、穗的钾含量均下降。抽穗期,氮、钾吸收量及干物质量红泰优996高于粤优589,磷吸收量粤优589高于红泰优996;成熟期,氮、钾吸收量及干物质量粤优589高于红泰优996,磷吸收量2品种差异不明显。2个杂交水稻品种地上部植株对氮、磷、钾积累量比例的变幅范围均在高产水稻积累变幅范围内。     

Potential angiotensin I converting enzyme inhibitory peptides from gluten hydrolysate: Biochemical characterization and molecular docking study

The present study was carried out to characterize ACE inhibitory peptides which are released from the trypsin hydrolysate of wheat gluten protein. In silico proteolitic digestion of a high molecular weight glutenin subunit was performed. Among the resultant fragments, four peptides were selected for chemical synthesis based on the chemoinformatics studies and docking properties. The ACE inhibitory activity and kinetic parameters of the most important peptides were determined. Molecular docking simulation was also performed to predict the sites on ACE in which these peptides bind and displayed inhibition mechanisms. Two peptide sequences of IPALLKR (P4) and AQQLAAQLPAMCR (P6) showed higher ACE inhibitory activity among peptide collection. The IC₅₀ values of P6 and P4 were 43 ± 1.3 μM and 68 ± 2.8 μM, respectively. P6 peptide was proved to be a more potent ACE inhibitor than P4 peptide. Lineweaver-Burk plots revealed that P6 and P4 behaved as non-competitive and competitive ACE inhibitors, respectively. The simulations showed that P4 bound to the active site region. Conversely, P6 bound to the N-terminus entrance of substrate tunnel and obstructed the substrate access into the catalytic site. Overall, the results showed that these peptides would be considered as a model for discovering new bio-compatible ACE inhibitors.     

不同基因型水稻镉吸收差异及镉对水稻的影响研究进展

研究镉对水稻污染的生理生物学的作用机制,筛选富镉或低吸镉的水稻基因型品种对保护生态环境和生产绿色食品都具有重要的理论意义和实用价值。综述了稻田镉污染的现状、危害,水稻镉吸收积累差异以及镉对水稻生长发育的影响等方面的研究成果,并提出了今后的研究方向。     

杂交水稻不同器官重金属铅浓度与累积量

以生长于盆钵中的两系杂交稻和三系杂交稻共6个组合为试验材料,设置土壤铅(Pb)浓度为500mg/kg和不加Pb土壤(对照)两个处理,测定水稻植株不同器官Pb的浓度和累积量。结果表明,Pb处理降低了两优培九、103S/郑粳2号、丰优香占和汕优63的产量,主要是每穗粒数减少,对其余组合的产量无显著影响;不同基因型水稻植株对Pb吸收与积累存在差异,以103S/郑粳2号和两优培九累积量最多,K优818累积量最少;水稻植株不同器官Pb的浓度和累积量的大小顺序为根>茎鞘>叶片。籽粒不同部位Pb的浓度大小顺序为糠层>颖壳>精米,精米中Pb累积量仅为谷粒的25%左右,精米中Pb的浓度以103S/郑粳2号最高,K优818最低;在抽穗期和成熟期,同一器官Pb浓度与累积量呈显著或极显著正相关,但不同器官之间的相关不显著。对不同杂交稻组合植株中Pb浓度和累积量差异的原因进行了讨论。     

玉米自交系耐盐种质的筛选及耐盐性评价

在0+0、2.5+2.5、5+5和7.5+7.5 mmol/L（Na₂CO₃+NaHCO₃）盐浓度胁迫下,对118份玉米自交系芽期、苗期的耐盐性差异进行比较,以主要农艺性状综合表现为依据筛选耐盐种质。各指标受盐害影响程度大小顺序为株高>芽势>叶长>根长>地上含水量>地下含水量>叶宽>芽率>须根数>根冠比>茎粗>根粗;当盐胁迫溶液为7.5 mmol/LNa₂CO₃+7.5 mmol/L NaHCO₃时,对玉米自交系影响差异显著。综合各个指标的盐害率对118份玉米自交系进行评价和排序,5个耐盐性强的自交系品种为DL、A71、PHB1M、A92和WM33;对盐敏感的5个品种为06NY-25、Mo17、郑32、南引26和农M1。