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71.
不同蛋白水平饲料对刺参生长和消化酶活性的影响   总被引:1,自引:0,他引:1  
通过在刺参饲料中添加不同含量的鱼粉,调节饲料中蛋白水平,测定不同蛋白水平对刺参(Apostichopus japonicus)消化酶活性的影响,以稳定同位素分析技术研究刺参对不同食物组分的吸收效率。实验分6个饲料处理组,鱼粉添加量分别为0(A组)、2%(B组)、5%(C组)、10%(D组)、15%(E组)和20%(F组)。实验过程中,分别于初始时间、第一周、第二周、第四周、第八周和第十二周采集刺参样品,测定刺参的特定生长率、稳定同位素13 C/12 C、15 N/14 N值和消化酶活性。结果显示:D组刺参的特定生长率最高,且与C组无显著差异(P0.05),F组显著低于其它组(P0.05);D组鱼粉对刺参的食物贡献率最高,显著高于其它组(P0.05);消化酶活性方面,蛋白酶和淀粉酶活性均为C组最高,且在饲养过程中,蛋白酶活性一直呈上升趋势,而淀粉酶活性则是先下降后上升。从刺参生长、鱼粉食物贡献率和消化酶活性综合考虑,鱼粉添加量在5%~10%最利于刺参生长。  相似文献   
72.
The effects of a diet containing Hanseniaspora opuntiae C21 on growth and digestive enzyme activity were estimated in juvenile Apostichopus japonicus. Groups of sea cucumbers were fed diets containing H. opuntiae C21 at 0(control), 10 4, 10 5, and 10 6 CFU(colony-forming units)/g feed. Results showed that after 45 d the specific growth rate(SGR) of sea cucumbers fed a C21-supplemented diet at 10 4 CFU/g feed was significantly higher than that of the control( P 0.05). Intestinal trypsin and lipase activities were significantly enhanced by C21 administration at 10 4 and 10 5 CFU/g feed compared with the control( P 0.05). After feeding for 23–42 d, C21 was demonstrated by denaturing gradient gel electrophoresis to be present in the intestine of sea cucumbers. In addition, after feeding the C21-supplemented diets for 15 d, the sea cucumbers were switched to an unsupplemented diet and C21 was confirmed to be capable of colonizing the intestine for at least 31 d after cessation of feeding. In conclusion, C21 was shown to successfully colonize the intestine of juvenile A. japonicus via dietary supplementation, and improve growth and digestive enzyme activity.  相似文献   
73.
Rice straw is supposed to be an environment-friendly biomaterial for inhibiting the growth of harmful blooms of the cyanobacterium Microcystis aeruginosa. However, its potential mechanism is not well known. To explore this mechanism, the growth, cell viability (esterase activity, membrane potential, and membrane integrity), photosynthesis, and cell size ofM. aeruginosa were determined using flow cytometry and Phyto-PAM after exposure to rice straw extracts (RSE). The results show that doses from 2.0 to 10.0 g/L of RSE efficiently inhibited the alga for 15 days, while the physiologic and morphologic responses of the cyanobacteria were time-dependent. RSE interfered with the cell membrane potential, cell size, and in vivo chlorophyll-a fluorescence on the first day. After 7 days of exposure, RSE was transported into the cytosol, which disrupted enzyme activity and photosynthesis. The cyanobacteria then started to repair its physiology (enzyme activity, photosynthesis) and remained viable, suggesting that rice straw act as an algistatic agent.  相似文献   
74.
黄海冷水团海域浮游植物磷胁迫的季节变动   总被引:2,自引:0,他引:2  
The Yellow Sea is located between the China Mainland and the Korean Peninsula, representing a typical shallow epicontinental sea. The Yellow Sea Cold Water Mass(YSCWM) is one of the most important physical features in the Yellow Sea. The characteristics of vertical profiles and seasonal variations of biogenic elements in the YSCWM may lead the variations of nutrient availability(e.g., phosphorus) and phosphorus stress of phytoplankton. In this study, the authors surveyed the seasonal variations of phytoplankton phosphorus stress with emphasis on the effect of the YSCWM during the four cruises in April and October 2006, March and August 2007. Using both bulk and single-cell alkaline phosphatase activity(APA) assays, this study evaluated phosphorus status of phytoplankton community, succession of phytoplankton community and ecophysiological responses of phytoplankton to phosphorus in the typical region of the YSCWM. With the occurrence of the YSCWM, especially the variations of concentration of dissolved inorganic phosphorus(DIP), the results of bulk APA appeared corresponding seasonal variations. Along Transects A and B, the mean APA in August was the highest, and that in March was the lowest. According to the ELF-labeled assay's results, seasonal variations of the ELF-labeled percentages within dominant species indicated that diatoms were dominant in March, April and October, while dinoflagellates were dominant in August. During the four cruises, the ELF-labeled percentages of diatoms except Paralia sulcata showed that diatoms were not phosphorus deficient in April 2006 at all, but suffered from severe phosphorus stress in August 2007. In comparison, the ELF-labeled percentages of dinoflagellates were all above 50% during the four time series, which meant dinoflagellates such as Alexandrium and Scrippsiella, sustained perennial phosphorus stress.  相似文献   
75.
Zygosaccharomyces rouxii is a salt-tolerant yeast species capable of removing cadmium(Cd) pollutant from aqueous solution. Presently, the physiological characteristics of Z. rouxii under the stress of sodium chloride(NaCl) and Cd are poorly understood. This study investigated the effects of NaCl and Cd on the growth, oxidative stress and antioxidant enzyme activities of Z. rouxii after stress treatment for 24 h. Results showed that NaCl or Cd alone negatively affected the growth of Z. rouxii, but the growth-inhibiting effect of Cd on Z. rouxii was reduced in the presence of NaCl. Flow cytometry assay showed that under Cd stress, NaCl significantly reduced the production of reactive oxygen species(ROS) and cell death of Z. rouxii compared with those in the absence of NaCl. The activities of superoxide dismutase(SOD), catalase(CAT), and peroxidase(POD) of Z. rouxii were significantly enhanced by 2%–6% NaCl, which likely contributed to the high salt tolerance of Z. rouxii. The POD activity was inhibited by 20 mg L-1Cd while the SOD and CAT activities were enhanced by 8 mg L-1 Cd and inhibited by 20 mg L-1 or 50 mg L-1 Cd. The inhibitory effect of high-level Cd on the antioxidant enzyme activities of Z. rouxii was counteracted by the combined use of NaCl, especially at 6%. This probably accounted for the decrease in Cd-induced ROS production and cell death of Z. rouxii after incubation with NaCl and Cd. Our work provided physiological clues as to the use of Z. rouxii as a biosorbent for Cd removal from seawater and liquid highly salty food.  相似文献   
76.
几种益生菌对大菱鲆幼鱼生长及消化酶活性的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
作者以初体质量为(4.80±0.11)g 的大菱鲆(Scophthalmus maximus)为研究对象,在循环水水族箱中进行60 d 饲喂实验,研究饵料中添加单一益生菌和复合益生菌对大菱鲆生长及消化道酶活性的影响.以基础饲料为对照组,在基础饲料中分别添加枯草芽孢杆菌(Bacillus subtilis)、地衣芽孢杆菌...  相似文献   
77.
龙雨娇  姚杰 《地理教学》2011,(16):32-33
在地理新课改的实践中,行为主义学习理论将地理课堂和实践操作紧密联系起来。地理作为一门实践性很强的学科,知识的获取并不能局限于课堂中的教学,我们应当跳出传统课堂的框架,结合有效的乡土资源,开设“第二课堂”,让学生通过“做中学”,获取直接经验的积累。  相似文献   
78.
一是调查摸底和统计分析相结合。该市要求各镇(街道)根据每年度农转用(征收)批次清单和已供建设项目台账,集中力量,落实责任人员.对1999—2010年已经办理农转用手续的土地和2007—2010年已供土地进行全面摸排:建立批而未供台账和供而未用台账。对每个批次中的未供土地逐项进行核对检查,按照绿化道路及安全间距等无法利用的土地、未供先用的违法用地和因其他原因造成的转而未供的土地等3种类型分别进行统计与处理;  相似文献   
79.
李文最 《地质实验室》1992,8(6):344-345
儿童生长发育、免疫功能和智力发育与人体必需的微量元素关系密切。由于头发易于取样和保存,且毛发中元素的含量是血和尿中的10~15倍。因而,头发分析日益受到人们的重视。近年来,相继出现了分析人发中微量元素的各种方法—AAS法、NAA法、XRF法、ICP—AES法等。而在同一消解液中,进行催化示波极谱法测定人发中Zn.Cu、Fe尚未见报道。本文研究、对比了不同的湿法消化体系,在同一份消解液中,进行人发中Zn、Cu、Fe的极谱测定。  相似文献   
80.
为了探究海带(Saccharina japonica)α-CA1和α-CA2是否具有催化CO2的可逆水合反应和酯酶活性,作者通过原核表达得到这两种α-CA的可溶性的异源重组蛋白。分别用电极法和酯酶活性检测法来检测重组α-CA1(rα-CA1)和rα-CA2的水合酶活性和酯酶活性,结果发现,rα-CA1的水合酶活性(1.52±0.120 U/mg)几乎是rα-CA2(0.54±0.046 U/mg)的3倍,表明rα-CA1催化CO2的水合能力明显大于rα-CA2。而两者的酯酶活性并没有显著的差别(rα-CA1比活力:0.697±0.176 U/g,rα-CA2比活力:0.743±0.129 U/g),说明催化乙酸对硝基苯酯(p-NPA)生成对硝基苯酚(p-NP)的能力是没有显著差别的。实验结果证实这2个α-CA为功能蛋白,可能参与海带无机碳吸收和储存过程,因此,本研究为海带无机碳吸收和储存机制的解析提供了生物化学依据。  相似文献   
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