Ameliorative Effects of Oyster Protein Hydrolysates on Cadmium-Induced Hepatic Injury in Mice

Cadmium (Cd) is a widespread environmental toxicant that can cause severe hepatic injury. Oyster protein hydrolysates (OPs) have potential effects on preventing liver disease. In this study, thirty mice were randomly divided into five groups: the control, Cd, Cd + ethylenediaminetetraacetic acid (EDTA, 100 mg/kg), and low/high dose of OPs-treatment groups (100 mg/kg or 300 mg/kg). After continuous administration for 7 days, the ameliorative effect of OPs on Cd-induced acute hepatic injury in Cd-exposed mice was assessed. The results showed that OPs significantly improved the liver function profiles (serum ALT, AST, LDH, and ALP) in Cd-exposed mice. Histopathological analysis showed that OPs decreased apoptotic bodies, hemorrhage, lymphocyte accumulation, and inflammatory cell infiltration around central veins. OPs significantly retained the activities of SOD, CAT, and GSH-Px, and decreased the elevated hepatic MDA content in Cd-exposed mice. In addition, OPs exhibited a reductive effect on the inflammatory responses (IL-1β, IL-6, and TNF-α) and inhibitory effects on the expression of inflammation-related proteins (MIP-2 and COX-2) and the ERK/NF-κB signaling pathway. OPs suppressed the development of hepatocyte apoptosis (Bax, caspase-3, and Blc-2) and the activation of the PI3K/AKT signaling pathway in Cd-exposed mice. In conclusion, OPs ameliorated the Cd-induced hepatic injury by inhibiting oxidative damage and inflammatory responses, as well as the development of hepatocyte apoptosis via regulating the ERK/NF-κB and PI3K/AKT-related signaling pathways.     

利用大豆浓缩蛋白乳清制备水苏糖的发酵条件

利用酵母对大豆浓缩蛋白乳清进行发酵处理制备水苏糖.在确定最佳起始发酵液的糖度为31.8Brix后,对温度、pH、接种量、装液量等工艺条件进行了单因素试验及正交试验,结果表明最佳发酵条件为:温度32°C,pH5.5,接种量8%,在此发酵条件下利用酵母对大豆浓缩蛋白乳清进行发酵处理48 h,水苏糖的纯度达到了90%,保留率为68%.     

酵母双杂交系统及其应用研究进展

酵母双杂交系统作为一种有效研究蛋白质相互作用的分子生物学方法,具有真实、高效、敏感、广泛的特点,被广泛应用于诸如蛋白质组学、基因组学等领域.主要对酵母双杂交技术的原理、特点及应用现状进行了综述.     

日粮中鱼蛋白水解物对黄颡鱼生长、体成分和血清生理指标的影响

为了探讨鱼蛋白水解物对黄颡鱼生产性能的影响,以日本鳀粉为对照,以实用型黄颡鱼饲料配方模式为基础开展实验:1以30.5%鱼粉为对照(FM),在相同配方模式下,以6%鱼蛋白水解物(MPH6)替代20%的鱼粉;2以30.5%鱼粉为对照(FM),在无鱼粉日粮中分别添加3%(FPH3)、6%(FPH6)、12%(FPH12)鱼蛋白水解物;共设计5组等氮等能实验日粮,在池塘网箱中养殖黄颡鱼[初始体质量(30.08±0.35)g]60 d。结果显示:与FM相比,FPH12在SGR、FCR、PRR和FRR方面均无显著差异,而MPH6、FPH3、FPH6组SGR降低了15.45%~24.39%,FCR升高了32.14%~42.86%,MPH6、FPH6差异显著,在PRR和FRR方面,MPH6、FPH3、FPH6组PRR降低了21.11%~27.78%,MPH6组FRR降低了41.51%;全鱼水分、粗蛋白、粗脂肪和灰分各组间差异不显著,FPH3、FPH6、FPH12肌肉多种游离氨基酸水平显著高于FM,其中Thr、Val、His与其在日粮中的水平显著相关;FPH6组HSI显著低于FM,鱼蛋白水解物对CP、VSI、肠体比的影响不显著;血清AST、ALT、HDL、LDL、TP、CHOL、TG无显著差异,FPH3组ALB显著低于FM。研究表明:黄颡鱼日粮中,12%鱼蛋白水解物(干物质)与30.5%鱼粉在生长速度、饲料效率、血清生理指标等方面具有一定的等效性;过高的植物蛋白日粮影响了黄颡鱼的生产性能;饲喂鱼蛋白水解物日粮使黄颡鱼肌肉游离氨基酸的含量升高,特别是呈味氨基酸的含量增加。     

含肽肝素渣水解物对早期断奶仔猪免疫功能的影响

本试验研究了含肽肝素渣水解物对早期断奶仔猪免疫器官生长发育、血清IgG含量、淋巴细胞数、腹泻指数以及生产性能的影响。试验表明,肝素渣水解后产生的寡肽可促进仔猪免疫器官发育,提高血清免疫球蛋白浓度、猪瘟抗体OD值和血液中淋巴细胞数,提高了断奶仔猪的免疫功能,降低了仔猪的腹泻指数,并能提高仔猪的日增重和饲料转化率。     

Antioxidative Effect of Chlorella Pyrenoidosa Protein Hydrolysates and Their Application in Krill Oil-in-Water Emulsions

Chlorella pyrenoidosa is an excellent source of protein, and in this research, we assessed the antioxidant and emulsifying effects of Chlorella protein hydrolysate (CPH) using neutral proteases and alkaline proteases, as well as the properties of CPH-derived krill oil-in-water (O/W) emulsions. The CPHs exhibited the ability to scavenge several kinds of free radicals, including 1,1-diphenyl-2-picrylhydrazyl (DPPH), O₂⁻, hydroxyl, and ABTS. Additionally, the CPHs (5 mg/mL) scavenged approximately 100% of the DPPH and ABTS. The CPHs showed similar emulsifying activities to Tween 20 and excellent foaming activities (max FS 74%), which helped to stabilize the krill oil-in-water emulsion. Less than 10 mg/mL CPHs was able to form fresh krill oil-in-water emulsions; moreover, the CPHs (5 mg/mL) in a krill O/W emulsion were homogenous, opaque, and stable for at least 30 days. Based on their inhibitory effects on the peroxide value (POV) and thiobarbituric acid reactive substances (TRABS), the CPHs were found to be able to inhibit lipid oxidation in both emulsifying systems and krill O/W emulsions. Thus, the CPHs could improve superoxide dismutase (SOD) activities by 5- or 10-fold and decrease the high reactive oxygen species (ROS) level caused by the addition of H₂O₂ in vitro. In conclusion, health-promoting CPHs could be applied in krill oil-in-water emulsions as both emulsifiers and antioxidants, which could help to improve the oxidative and physical stability of emulsions.     

一种基于硼氢化钠的新型储氢材料研究

硼氢化钠的水解产物是一种新的储氢材料，其良好的可逆储氢能力在5MPa氢气压力真空条件下3分钟后在室温下吸收氢150。根据报道，它已被证明，这两种改变的催化剂NaBH4水解和添加催化剂直接插入接口是两个非常有效进一步提高接口的储氢容量。对hpsb-y2o3脱氢TiO2分别掺杂均达到重量2.4%和重量4.6%。重要的是对hpsb-y2o3可逆的脱氢能力不下降后成功———超循环。相比之下，对hpsb-ceo2可逆脱氢高达到重量5.9%，在室温下5分钟后3MPa氢气压力150氢吸附。     

仿生法评定抗草甘膦玉米和转Bt基因玉米的酶水解物能值的研究

本试验旨在分析抗草甘膦玉米和转Bt基因玉米原料及饲粮与同源非转基因玉米原料及饲粮体外总能消化率以及酶水解物能值,为转基因玉米的营养实质等同性仿生评定方法的研究提供参考。试验采用单因素完全随机设计,使用单胃动物仿生消化系统模拟饲料原料和饲粮在鸡胃肠道的消化过程,分析同源非转基因玉米、抗草甘膦玉米和转Bt基因玉米以及对应的3种玉米-豆粕饲粮在不同体外模拟消化阶段的干物质消化率、总能消化率和酶水解物能值的差异。结果表明:同源非转基因玉米、抗草甘膦玉米和转Bt基因玉米以及对应饲粮在常规概率成分含量上是相似的。抗草甘膦玉米及饲粮与同源非转基因玉米及饲粮相比,在干物质和能量胃消化率、全消化道消化率及酶水解物能值上均没有显著差异(P0.05)。转Bt基因玉米全消化道总能消化率低于同源非转基因玉米(P=0.03,变异系数=0.50%),对应玉米饲粮的酶水解物能值则高于同源非转基因玉米饲粮(P=0.02,变异系数=1.12%),但均处于仿生消化系统测试的误差范围内(变异系数≤1.64%)。由此可见,抗草甘膦玉米的酶水解物能值与同源对照玉米没有差异,而转Bt基因玉米存在统计学意义上的差异,但所有的测值均处于仿生消化系统的测试误差之内。仿生法发现的差异是否具有生物学意义有待体内试验验证。仿生法可为转基因饲料营养等同性研究提供一种新方法。     

大肠杆菌表达系统和酵母表达系统的研究进展

由于DNA重组技术和蛋白组技术的发展与成熟,外源基因表达技术备受关注。其在生物、食品、工业以及医学领域发挥着举足轻重的作用。以原核生物细胞及真核生物细胞作为表达系统,进行目的基因序列的表达以生产蛋白疫苗、核酸疫苗和生物酶制剂等是近年来发酵工业的新型领域。原核和真核表达系统是近年来研究和应用最广泛和最成熟的外源基因表达系统。对近年来关于大肠杆菌表达系统和酵母表达系统的研究进展进行了综述。     

Effect of Partial Replacement of Steam Rolled Corn With Soybean Hulls or Prickly Pear Cactus in the Horse's Diet in the Presence of Live Saccharomyces cerevisiae on In Vitro Fecal Gas Production

The aim of the study was to evaluate the fecal fermentation of partial replacing steam rolled corn with soybean hulls (SH) or prickly pear cactus (PC) as energy source in horse diets, in the presence of Saccharomyces cerevisiae. Steam rolled corn was replaced with SH at 0% (control), 7.5% (SH75), and 15% (SH150) in the first trial, whereas it was replaced with PC at 0% (control; the same of the first trial), 7.5% (PC75), and 15% (PC150) in the second trial. Yeast of S. cerevisiae was added at 0, 2, and 4 mg/g dry matter (DM) of incubated substrates. Fecal inoculum was obtained from four adult English Thoroughbred horses fed on an amount of commercial concentrate and oat hay ad libitum. Interactions observed between PC rations and yeast doses for the asymptotic gas production (GP), the rate of GP and carbon dioxide (CO₂) production during some incubation hours. Moreover, with no effect due to SH rations (P > .05), increased (P < .05) rate of GP was observed with the ration PC75 compared with other rations. Besides, PC75 and PC150 rations with 0 mg yeast/g DM linearly decreased (P < .05) CO₂ production at some incubation hours. However, SH75 and SH150 ration had increased (P = .005) DM degradability (DMD). Yeast addition at 2 mg/g DM increased the asymptotic GP (P = .048) with the SH75 and PC150 rations. The level of 4 mg yeast/g DM increased the asymptotic GP (P = .048) from the SH150 ration. Yeast addition at 2 and 4 mg/g DM increased (P < .05) ​the asymptotic GP from PC75 and PC150 rations, respectively, with increasing DMD with the both doses. Yeast addition increased (P < .05) CO₂ production from SH75, SH150, PC75, and PC150 rations. It could be concluded that SH and PC can replace steam rolled corn at levels of 7.5% to 15% without negative effect of fermentation kinetics and with better fermentation performance in the presence of yeast at 2 mg/g DM of substrates.