褐藻酸钠对向日葵幼苗耐盐性的影响

研究了褐藻酸钠对向日葵幼苗遭受盐胁迫的缓解作用。结果表明:在6 g/L的氯化钠胁迫下,加入0.5 g/L褐藻酸钠后,向日葵幼苗的存活率提高了69.1%,株重增加了54.7%,叶绿素含量提高了47.6%,根数增加了55.6%,根长增加了30.8%,SOD活性增强了50.2%;褐藻酸钠可提高向日葵幼苗的耐盐适应性,缓解氯化钠胁迫造成的伤害。     

基于响应面法的海藻酸钠固定β-呋喃果糖苷酶工艺优化

糖苷酶在水解/合成生产功能性食品配料(含低聚糖)方面扮演着重要角色。为提高糖苷酶的重复利用率与稳定性,本文对影响海藻酸钠固定化β-呋喃果糖苷酶(β-fructofuranosidase,FFase)工艺的因素进行分析,利用响应面法对固定化酶工艺进行优化,最后对所得固定化酶的稳定性进行评价。结果表明:影响海藻酸钠固定化FFase工艺的关键因素及最佳条件为4 g/L海藻酸钠、固定42 min、交联温度26℃,酶活回收率为60.95%;在此条件下与游离酶相比,4℃下保存12 d后,酶活力依然有60%以上,具有良好的储存稳定性;在温度低于70℃范围内有良好的热稳定性。连续使用5次后,其固定酶活仍保持初始酶活的51.71%,具有良好的重复再利用性。     

丝素-海藻酸钠-甘油共混膜的制备及性能研究

以丝素蛋白为原料,海藻酸钠和甘油作为添加剂,考察丝素蛋白溶液、海藻酸钠溶液的浓度和甘油的加入量对膜的厚度、断裂伸长率以及水蒸气迁移速率的影响,并通过正交试验来确定丝素-海藻酸钠-甘油共混膜的最佳配比.试验结果表明,最佳配方为丝素溶液浓度3%,海藻酸钠溶液浓度12.5 mg·mL-1,甘油加入量0.5 mL.在此条件下,膜的厚度、断裂伸长率及水蒸气迁移速率分别为0.075 mm、45.53%和13.76 g·m-2·h-1.     

肉桂油/海藻酸钠薄膜物理特性和抗菌性能分析

为了研究开发新型可降解抗菌包装材料,该文以添加不同体积肉桂油到海藻酸钠膜液中制成的肉桂油/海藻酸钠抗菌薄膜为研究对象,比较分析肉桂油添加量对肉桂油/海藻酸钠薄膜厚度、透光率、色泽和水蒸气透过率等物理特性的影响,同时,考察其对薄膜的抗菌性能的影响。膜液中肉桂油体积分数在0～1.0%时,薄膜厚度无明显变化,体积分数为1.2%时,薄膜厚度显著增加。随着肉桂油体积分数的增加,薄膜的透光率显著降低,薄膜水蒸气透过系数增大。肉桂油对薄膜色泽影响显著,随着肉桂油添加量的增加,薄膜色泽值a和b呈显著增加趋势。膜液中肉桂油体积分数为0.8%时,薄膜抗菌能力显著增强。研究结果表明,当膜液中肉桂油体积分数为0.8%时,薄膜具有较好的抗菌效果和物理性能。该研究可为肉桂油/海藻酸钠可降解抗菌薄膜生产工艺参数的进一步优化提供参考。     

海藻酸钠固定化细菌对毒死蜱的降解特性

毒死蜱的生产和使用日趋广泛,由其造成的环境污染和危害不容忽视。微生物是影响有机磷农药在环境中降解的最主要因素,也被认为是降解有机磷农药最可靠而高效的途径。固定化技术是提高微生物降解农药效率的有效方法之一。本研究以海藻酸钠为载体,采用注射器滴定法将蜡状芽孢杆菌(Bacillus cer-eus)HY-1用海藻酸钠溶胶包埋,研究了反应时间、固定化菌接入量、pH和毒死蜱初始浓度对毒死蜱降解的影响以及固定化菌的重复使用效果。结果表明:海藻酸钠固定化菌能够高效降解基础培养基中的毒死蜱,制备固定化小球海藻酸钠溶胶的最适浓度为2.5%(w/v),小球的平均粒径为3 mm。在培养时间为60 h时,固定化菌对100 mg·L-1毒死蜱的降解率达到最大。固定化小球接入量为160 g·L-1时,对100 mg·L-1毒死蜱的降解率最高。固定化菌对毒死蜱的降解有着较宽泛的pH适应范围,碱性环境更有利于其对毒死蜱的有效降解。当毒死蜱初始浓度为80 mg·L-1和100 mg·L-1时,固定化菌对毒死蜱的降解率较高,达90%左右。固定化菌可重复利用降解毒死蜱,当利用4次后,固定化小球虽已发生崩解,但对100 mg·L-1毒死蜱的降解率仍高达47%。因此,海藻酸钠固定化蜡状芽孢杆菌对水体中毒死蜱的降解率较高,环境适应性较强,固定化菌可在毒死蜱污染的净化去毒方面发挥重要作用。     

大枣低聚糖对蛋雏鸡生长性能和免疫功能的影响

试验选用罗曼1日龄蛋雏鸡200羽,采用单因子随机设计,分成4组(空白组、试验1组、试验2组、试验3组),每组5个重复,分别饲喂添加0、500、1000、1500 mg/kg大枣低聚糖的基础日粮,试验期35 d,探讨大枣低聚糖对蛋雏鸡生产性能和免疫机能的影响。结果表明:与对照组相比,试验2组、3组日均采食量分别提高了9.4%和8.9%(P<0.05),平均日增重分别提高了14.8%和13.1%(P<0.05);试验2、3组脾脏指数、胸腺指数、法氏囊指数、IgA和IgG水平均显著提高(P<0.05);试验1组脾脏指数、胸腺指数和IgA水平均显著提高(P<0.05)。本试验表明,饲料中添加大枣低聚糖可提高蛋雏鸡的生产性能和免疫机能,其中日粮中添加量为1000 mg/kg效果较理想。     

大豆黄浆水处理过程中超滤膜的选择

通过实验研究了不同截留分子量和膜材料的超滤膜在超滤大豆黄浆水时的渗透通量、膜衰减系数、蛋白质截留率和总糖透过率,结果表明:PS-10膜是分离大豆黄浆水的适宜用膜。     

Healing and Preventive Effects of Calcium Alginate on Carbon Tetrachloride Induced Liver Injury in Rats

The purpose of this study was to investigate the pharmacological effects of calcium alginate on carbon tetrachloride (CCL₄)-induced hepatotoxicity in rats. The study included two experiments. In the first experiment the animals were given daily CCL₄ through gavage for 7 days and then 10, 50, or 250 mg/kg b.w. of calcium alginate for 21 days. The increased bilirubin level, enhanced alanine and aspartate aminotransferase activity in plasma and reduced liver glycogen content induced by CCL₄ were partly normalized by alginate administration in a dose-dependent manner. In addition, alginate significantly improved CCL₄-induced alterations of pro-oxidant and antioxidant biochemical parameters in liver and plasma compared to those of rats administered CCL₄. In the second experiment the animals were given daily 10, 50 or 250 mg/kg b.w. of calcium alginate for 21 days before 7-day administration of CCL₄. Pretreatment with alginate before CCL₄ administration resulted in significantly inhibited increase of the blood enzymatic activities of alanine and aspartate aminotransferases and bilirubin level in a dose-dependent manner. Also, preliminary administration of alginate prevented elevation of lipid peroxidation products and reduction of liver glutathione content in rats given CCL_4. These results suggest that calcium alginate exerts healing and preventive effects on CCL₄-induced hepatotoxicity in rats.     

海藻酸钠地膜制备及其性能研究

[目的]针对塑料地膜造成的白色污染问题,研究了可降解海藻酸钠地膜的制备方法.[方法]研究了海藻酸钠浓度、增塑剂种类及浓度和持水剂浓度对膜性能的影响,并通过大田试验研究了膜的降解情况.[结果]随着海藻酸钠浓度的增大,膜的拉伸强度和断裂伸长率逐渐上升.增稠剂提高了膜的拉伸强度和断裂伸长率,其中羧甲基纤维素钠的效果最好.持水剂使膜的拉伸强度和断裂伸长率降低,但解决了膜干裂的问题.[结论]海藻酸钠地膜最佳成膜液的组成为:1.0％海藻酸钠、0.2％羧甲基纤维素钠和0.6％甘油,此时海藻酸钠地膜的膜薄、拉伸强度和断裂伸长率高、透光率好,且可生物降解.     

Impact of Fusarium oxysporum on the holoparasitic weed Phelipanche ramosa: biocontrol efficacy under field-grown conditions

Under the changing agro-climatic conditions of western Europe, the parasitic weed Phelipanche ramosa infests host crops such as tomato, hemp, tobacco and oilseed rape at an increasing rate. A Fusarium oxysporum isolate (FOG), that had effectively reduced the parasite's incidence under controlled environmental conditions, was tested in different granular formulations (pesta granules, alginate pellets) on P. ramosa parasitising tobacco under field-grown conditions. FOG reduced number and biomass of P. ramosa shoots by between 50% and 70% in three consecutive years (2006–2008). A single pesta application did not show consistent results throughout seasons; 50% reduction of P. ramosa biomass (DM) in the first year could not be repeated in the following years (20–30%). An alginate formulation applied alone performed better. However, a combination of pesta granules with alginate pellets had the highest reliable control efficacy (60–70%) of all treatments in two seasons, compared with the untreated control. Fungal population counts in soil samples did not show a close correlation to biocontrol efficacy. To understand field performance of this biocontrol agent, additional glasshouse and laboratory studies were conducted using soil from the experimental site. The glasshouse study revealed some fungistatic effects of the field soil that partly explain the reduced efficacy (-40%) in the field compared with results obtained under controlled conditions. Results show the potential of FOG for P. ramosa control. Because formulation affected the biocontrol efficacy, it may be worthwhile to test how the delivery system can be changed in order to achieve increased disease development in the field.