Expression of pancreatic enzyme genes during the early larval stage of Japanese eel Anguilla japonica

ABSTRACT: To reveal the ontogeny of pancreatic exocrine function in the early larval stage of eel, cDNAs encoding major pancreatic enzymes, trypsinogen, amylase and lipase were identified from the Japanese eel Anguilla japonica and their expression pattern in larvae was analyzed. The cloned eel trypsinogen precursor consisted of 224 amino acids and showed 82.2% identity to trypsinogen-2 of winter flounder Pleuronectes americanus . The eel amylase precursor consisted of 512 amino acids and showed 77% identity to winter flounder amylase. Eel pancreatic lipase was composed of 470 amino acids and had 58.3% of identity to human pancreatic lipase. In the eel larvae, mRNA expression of trypsinogen and amylase was first detected at 6 days post-hatching (d.p.h.), and the expression level increased between 7 and 8 d.p.h. In contrast, mRNA expression of lipase was first detected at 8 d.p.h. Eel larvae start to feed actively at 8 d.p.h. Thus, it was indicated that eel pancreas starts to synthesize digestive enzymes at 6 d.p.h. and acquires full function by the onset of exogenous feeding at 8 d.p.h.     

Effects of dietary protein levels on the growth,survival, amylase and trypsin activities in large yellow croaker,Pseudosciaena Crocea R., larvae

A feeding trial was conducted to investigate the effects of dietary graded protein levels on the growth, survival, amylase and trypsin activities of large yellow croaker (Pseudosciaena crocea R.) larvae from 12 to 42 days after hatching (DAH). Five approximately isoenergetic microbound diets (16.65 MJ/kg diet) were formulated to contain different protein (47.1%, 52.0%, 57.1%, 62.2% and 67.5%) levels. Frozen copepods, containing 54.5% crude protein (CP), 6.0% crude lipid, 27.2% ash and 6.7% glycogen, were used as a control. Each diet was randomly fed to triplicate groups of larvae with an initial mean body weight of 1.76 ± 0.09 mg (mean ± SD) in 180 L white plastic tanks, and each tank was stocked initially with 3500 larvae. Both the survival and the specific growth rate (SGR) of large yellow croaker larvae significantly increased with increasing dietary protein level up to 57.1%, and decreased thereafter. Frozen copepods resulted in intermediate survival and low SGR compared with the other diets. Whole‐body moisture and protein of larvae were not significantly affected by the dietary protein level. In contrast, whole‐body lipid of larvae fed diet with 47.1% CP was significantly higher (P<0.05) than those from fish fed the diets containing more than 57.1% CP. Additionally, fish fed the frozen copepods had the lowest whole‐body protein and lipid. The amylase‐specific activity increased with increasing dietary carbohydrate level during the period of this experiment. However, trypsin activity was not significantly affected by the dietary protein content before 42 DAH, indicating a later onset of trypsin than amylase in the regulation of enzymatic synthesis induced by a dietary substrate.     

鲤鱼肠道细菌及其淀粉酶对宿主消化的影响

本文就鲤鱼肠道细菌对其宿主的影响和细菌淀粉酶对宿主消化的影响作了探讨。从鲤鱼肠道筛选细菌菌株６３株，这上结细菌中淀粉酶产生菌分布较广，溶血毒素产生菌较少，且产毒素的６株菌无致病性。淀粉酶活力较高的ＣＣＩ１３９菌株的淀粉酶和鲤鱼肝胰淀粉酶的最适ｐＨ和反应产物都不相同。原位酶反应法显示鲤鱼肠道食物混合液及肠壁样品中均有细菌淀粉酶。本文结果证明了鲤鱼肠道不稳定的细菌群落，细菌淀粉酶对鲤鱼消化食物的淀粉起     

不同浓度蔗糖诱导马铃薯微型薯形成时α-淀粉酶活性分析

利用不同浓度蔗糖诱导马铃薯微型薯 ,所生成的微型薯的产量不同。α 淀粉酶是马铃薯微型薯生长发育有关的一项重要生理生化指标 ,与块茎形成过程中干物质的积累密切相关。本文对在不同浓度蔗糖下形成的微型薯的α 淀粉酶活性进行分析 ,其结果表明 ,α 淀粉酶的活性与微型薯产量呈显著负相关     

猪血清淀粉酶多态性及遗传规律研究

采集２６７头二花脸、大约克纯种猪及它们的不同杂交组合后代血样，利用水平聚丙烯酰胺凝胶电泳法，对血清中淀粉酶（Ａｍ）的遗传多态型及遗传规律进行研究，并分析了血清淀粉酶型对猪初生重的影响。结果表明猪血清症粉酶表现出多态性，有九种表现型并分别受四个共显性复等位基因控制，而其他文献大多提及Ａｍ受三个共显性复等位基因控制，并有六种表现型。Ａｍ基因型的九个交配组合后代基因型经Ｘ￣２检验，有两个交配组合（ＢＤ×ＣＤ，ＢＤ×ＡＤ）的分离比Ｘ￣２值Ｐ＜０．０１差异极显著；有两个组合（ＢＤ×ＢＣ，ＢＣ×ＣＤ）的分离比Ｘ￣２值Ｐ＜０．０５，差异显著；其他五个组合（ＢＤ×ＡＣ，ＣＤ×ＢＢ，ＣＤ×ＡＢ，ＢＤ×ＣＣ，ＢＣ×ＤＤ），分离比Ｘ￣２值Ｐ＞０．０５，差异不显著，符合孟德尔遗传规律。有些交配组合分离比与预期比不符合，是否由于某些基因型与生命力有关，还有待于进一步探讨。猪血清淀粉酶型与仔猪初生重相关关系不明显。     

鸡胰和十二指肠淀粉酶的提纯和性质

用硫酸铵沉淀、离子交换层析和亲和层析等方法,从鸡的胰和十二指肠中提纯了胰淀粉酶(P-Amyl)和十二指肠淀粉酶(D-Amyl).提纯倍数分别为67.5倍和78.8倍.二者提取液等电聚焦电泳鉴定均出现1条酶带,等电点分别为4.5和4.6.聚丙烯酰胺梯度凝胶电泳测定,二者的分子量均为53500.以可溶性淀粉为底物,测得P-Amyl和D-Amyl的Km值分别为6.20×10~-5和1.16×10~-5mol/L.P-Amyl对热敏感,D-Amyl则较稳定.EDTA强烈地抑制P-Amyl的活性,而对D-Amyl的抑制作用弱.P-Amyl和D-Amyl的最适pH分别为7.0和6.6.对P-Amyl和D-Amyl,Ca~(2+)、Mg~(2+)和Co~(2+)均有不同程度的激活作用,Cu~(2+)和Mn~(2+)有抑制作用;Zn~(2+)对P-Amyl有抑制作用;低浓度Fe~(3+)对P-Amyl有激活作用,高浓度Fe~(2+)对P-Amyl和D-Amyl均有抑制作用.     

Gelatinized to non-gelatinized starch ratio in the diet of Labeo rohita: effect on digestive and metabolic response and on growth

A 60-days experiment was conducted to study the optimum gelatinized (G) to non-gelatinized (NG) starch ratio in the diet of Labeo rohita juveniles with respect to digestive and metabolic response and on growth. Two-hundred and thirty-four juveniles (avg. wt 2.53 ± 0.04 g) were randomly distributed in six treatment groups with each of three replicates. Six semipurified diets either containing NG and/or G corn starch viz., T₁ (100% NG, 0% G starch), T₂ (80% NG, 20% G starch), T₃ (60% NG, 40% G starch), T₄ (40% NG, 60% G starch), T₅ (20% NG, 80% G starch) and T₆ (0% NG, 100% G starch) were prepared. The dry matter digestibility and carbohydrate digestibility were highest (p < 0.05) in T₆ group and lowest in T₃ and T₄ groups. The amylase activity in intestine increased as G:NG level increased in the diet. Protease activity in intestine was highest in T₆ group and lowest in T₁ group. Similar trend was recorded for specific growth rate, protein efficiency ratio and apparent net protein utilization. Liver glycogen, hepatosomatic index and blood glucose level increased linearly with the increasing level of G starch in the experimental diet. The results indicate that higher nutrient digestibility and growth was recorded either at low (20% G starch, T₂) or high (100% G starch, T₆) G starch fed group. But high G starch fed group (T₆) exhibits higher liver glycogen and blood glucose level, which may lead to stress due to long-term feeding. Hence, it is suggested that 20% G and 80% NG starch is optimum for better nutrient digestibility and growth in L. rohita juveniles.     

Dynamic Characteristics of Soil Sucrase and Amylase Activities during Vegetation Degradation in Gahai Wetland北大核心CSCD

In order to study the activities and dynamic characteristics of soil invertase and amylase during the process of vegetation degradation (Non-degradation, Light degradation,Moderate degradation, and Heavy degradation),the filed experiments were conducted in marsh meadow of Gahai wetland in Gannan state,Gansu province. The main results were as following: the average activity values of invertase and amylase activities in 0~100 cm layers varied in different stages of vegetation degradation of marsh meadow, following the order of CK (Non-degradation) > SD (Light degradation) > MD (Moderate degradation) > HD (Heavy degradation). With the increasing of soil layers,the activity of invertase significantly decreased (P<0.05),while the activity of amylase decreased fluctuantly. The activities of enzymes in the surface soil (0~20 cm) accounted for more than 60% of the total activities of each enzyme. The activities of invertase and amylase showed the obvious dynamic characteristics with time in all stages of vegetation degradation. The average activity of invertase in different months was the highest in June (47.07 mg·g-1) and the lowest in August (22.69 mg·g-1). The average activity of amylase was the highest in July,85.18 mg·g-1,while the activity values in other months were low. Correlation analysis showed that soil organic carbon was significantly correlated with invertase and amylase (P<0.01),and soil water content was only significantly correlated with invertase (P<0.01). The results showed that the vegetation degradation in Gahai wetland significantly affects soil invertase and amylase activities,reduces the efficiency of enzymatic reaction,and leads to the deterioration of wetland soil environment. © 2019 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.     

百合种球大小对不同发育阶段鳞茎中糖和淀粉含量及淀粉酶活性的影响

以兰州百合与亚洲系精粹百合鳞茎为试材,研究不同规格鳞茎发育过程中糖和淀粉含量及淀粉酶活性的变化。结果表明：较小规格鳞茎淀粉积累始期与高峰期分别比较大规格鳞茎提前约10d。兰州百合鳞茎A[φ=（6．4&#177;0．6）cm]可溶性糖的积累比鳞茎B[Φ=（4．9&#177;0．3）cm]提前10d,而精粹百合鳞茎C[φ=（6．0&#177;0．5）cm]比鳞茎D[Φ=（4．3&#177;0．5）cm]提前20d。精粹百合萌发阶段总可溶性糖的下降幅度大于兰州百合。百合鳞茎中的α-淀粉酶活性显著高于β-淀粉酶活性,并且较大鳞茎的淀粉酶活性高于较小鳞茎。采收期不同,不同规格的百合鳞茎内部的碳水化合物含量水平有较大差异。兰州百合鳞茎A淀粉含量在植株半枯期达到最大值（30.39％）,鳞茎B花后60d淀粉含量达最大值（37．87％）。     

不同物候期芍药根淀粉酶活性的变化

采用DNS比色法,精确测定了不同物候期芍药根中淀粉酶的活性。结果表明,芍药出苗到开花期,α淀粉酶活性由低到高,在孕蕾期达到最高峰;β淀粉酶活性变化与α淀粉酶相反,只在苗期具有显著活性。芍药的质量与其粉性有一定关系,且淀粉含量与芍药体内淀粉酶的活性变化密切相关。