广西八角良种研究综述

八角主产广西,是南亚热带重要的香料树种。广西的八角良种研究始于20世纪80年代初,经过全区品种资源普查,划定了17个农家品种,确定4个类型为优良类型,然后继续优良个体的选择,突破了无性繁殖技术的关键,初步选出了优良单株,并有3个无性系通过区级良种认定。     

水牛卵母细胞孤雌激活及孤雌胚与体外受精胚发育比较

比较了水牛卵母细胞体外成熟时间对孤雌激活胚发育能力的影响,以及不同化学激活方法对水牛卵母细胞孤雌激活效果的影响,并在相同条件下,对孤雌激活胚与体外受精胚的发育能力进行了比较.结果表明,水牛卵母细胞体外成熟27 h或30 h的囊胚发育率(19.0%、17.7%)明显高于体外成熟21 h或24h的囊胚发育率(12.3%、13.8%);Ion联合6-DMAP激活水牛卵母细胞的效果优于其他几组激活方法;在相同条件下,孤雌激活胚与体外受精胚的发育能力存在着差异,其中卵裂率差异不显著,但孤雌激活胚的囊胚发育率显著高于体外受精胚.     

基于液压加载的拖拉机PTO测试装置设计与试验

针对当前多数负荷车仅适用于拖拉机牵引试验测试,模拟完整田间作业状态不全面的现状,设计了一种可挂接负荷车的液压加载式拖拉机动力输出轴测试装置,在满足负荷车牵引试验国标要求的基础上可以进行拖拉机PTO测试试验。该装置采用的液压测功机与应用普遍的直流电力测功机经过试验对比,系统响应和稳定速度更快,综合加载性能更好。对该测试设备进行拖拉机PTO田间转矩载荷谱模拟动态加载试验,结果显示：实际加载转矩与转矩载荷谱试验数据相关性良好,拟合优度为0.83。通过数据分析计算实际液压加载系统响应时间约为2.1s,最大超调量为7.52%,均在可控范围内。说明该测试设备可以通过输入转矩载荷谱的形式有效模拟田间作业拖拉机PTO工作状态,为后续拖拉机牵引及转矩全面加载田间模拟试验提供参考。     

小肽对大黄鱼仔鱼生长和小肠发育的影响及其在低温胁迫下的抗氧化应激效应

本试验分为生长试验和低温胁迫试验2部分.先分别投喂大黄鱼(Larimichthys cro-cea)仔鱼经不同浓度(0、0.5、1.0、2.0和3.0 mL/m3)小肽营养强化后的轮虫和卤虫12 d,以探讨小肽对大黄鱼仔鱼生长和小肠发育的影响;再将大黄鱼仔鱼暴露在温度为12℃的水体中24 h,以探讨小肽对低温胁迫下大黄...     

建兰花叶病毒广东分离物的全基因组序列分析

【目的】建兰花叶病毒(Cymbidium mosaic virus,CymMV)是最主要的兰花病毒病原之一,其广泛传播对兰花产业发展造成严重威胁。探究CymMV遗传信息和进化,为广东省兰花病毒病的监测预警和兰花抗病毒病基因工程提供重要科学依据。【方法】对采自广州地区的墨兰疑似病毒病叶片进行CymMV的RT-PCR及DA-SELISA检测鉴定,利用相关分子生物学软件对CymMV分离物进行基因组序列组装、注释、系统进化及选择压力分析。【结果】首次在广东省发现2个CymMV分离物GZV013和ZC-29,基因组全长均为6227 nt,编码5个功能蛋白;GZV013与台湾分离物M2的核苷酸序列一致性为97.03%;ZC29与南京分离物NJ-1的核苷酸序列一致性为97.11%;CymMV各分离物的全基因组序列一致性为86.85%～98.31%,且多样性种群的分化与寄主种类和地理隔离关系密切;CymMV基因组每个区域均受到负选择的影响,并符合中性进化模型;编码RdRp、TGB1和TGB2的基因在基因组中变异率最高。【结论】GZV013与台湾分离物M2的亲缘关系最近,ZC29与南京分离物NJ-1的亲...     

Vitellogenin in tilapia (Oreochromis mossambicus): Induction of two forms by estradiol,quantification in plasma and characterization in oocyte extract

Two forms of vitellogenin were isolated by DEAE agarose ion-exchange chromatography from plasma of the tilapia, Oreochromis mossambicus. The monomers have apparent molecular masses of 200 and 130 kDa, as indicated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), and a total amount of phosphorus of 1.7 and 0.1%, respectively. Antibodies specific to the two forms, designated tVTG-200 and tVTG-130, were generated in rabbits and used to develop enzyme-linked immunosorbent assays (ELISAs) and in Western blot analyses of plasma and oocyte extract. SDS-PAGE of the oocyte extract showed a major protein band at 106.6, minor bands at 26.6, 24.2, and 23.7 kDa, and very faint bands at 83.4 and 17.5 kDa. Western blots of the oocyte extract revealed that the antiserum to tVTG-200 recognized strongly the protein bands at 24.2 and 23.7 kDa, and less strongly the bands at 25.1 and 22.6 kDa, whereas the antiserum to tVTG-130 recognized mainly the protein band at 106.6 kDa. The presence of both VTGs in untreated male tilapia was detected with the ELISAs using relatively high plasma volumes. Their presence in males was confirmed by VTG-like immunoreactive materials eluting from the ion-exchange column at the same positions as tVTG-200 and tVTG-130. The concentrations of the VTGs in males were several orders of magnitude lower than in vitellogenic females. Treatment of male tilapia with estradiol-17β (E₂) induced both VTGs within 24h. After 7 days, tVTG-130 reached a maximum concentration in plasma, whereas tVTG-200 continued to increase. Our findings demonstrate that the two vitellogenins are biochemically distinct, possibly differentially regulated, and made by both sexes.     

鲢肠道淀粉酶的分离纯化及部分性质研究

以鲢(Hypophthalmichthys molitrix)加工下脚料为原料,分离提纯其中的淀粉酶并对其部分性质进行了研究。结果表明经多级分离,得到了一种相对分子质量约2.15×104的淀粉酶,命名为SCIG1。SCIG1是鲢肠道淀粉酶的一种,酶活性的最适温度为30℃,最适pH5.5。     

Stability comparison of three candidate internal reference genes in Chinese giant salamander (Andrias davidianus)

The Chinese giant salamander (Andrias davidianus) as food and medicinal product has been an important aquaculture object in China. Study of gene function in the Chinese giant salamander requires accurate normalization though the use of appropriate reference genes. In this study, the expression levels of three candidate reference genes including β‐actin, GAPDH and cytb of different tissues, different developmental stages and different challenges in Chinese giant salamander were evaluated by qPCR. The stabilities of these three reference genes were analysed by geNorm, NormFinder and BestKeeper software. The results showed that the expression of GAPDH was more stable than that of β‐actin and cytb in four tissues and at two developmental stages of Chinese giant salamander. Compared with GAPDH and cytb, β‐actin was the most stable in spleen of Chinese giant salamander treated with LPS or GSIV. Therefore, the result showed that GAPDH was the suitable reference gene in different tissues and at different developmental stages of Chinese giant salamander. The β‐actin could be used as a reference gene in spleen of Chinese giant salamander challenged with LPS and GSIV. This study provides convincing information for the GAPDH and β‐actin as suitable reference gene in Chinese giant salamander of different tissues, different developmental stages and different challenges respectively.     

发酵黄芪对山瑞鳖稚鳖生长性能的影响

采用单因素试验方法,研究发酵黄芪对山瑞鳖(Palea steindachneri)稚鳖生长的影响。选用960只稚鳖,随机分为4个处理组,每个处理组3个重复,每个重复80只。以基础饲料(幼鳖粉料)为对照组,试验组分别在基础饲料中添加0.2%、0.4%、0.6%发酵黄芪,饲养60 d。结果显示:1~#、2~#、3~#试验组稚鳖的增重率、成活率均显著高于0~#对照组(P<0.05),饲料系数显著低于0~#对照组(P<0.05);试验组之间差异不显著(P>0.05),以0.4%发酵黄芪组综合效果最好,与0~#对照组比,其均末重、成活率分别提高了31.86%、8.26%,饲料系数降低了14.58%。试验结果表明:发酵黄芪能显著促进稚鳖生长、提高成活率和饲料利用率的作用。     

Preparation and Characterization of Protein Hydrolysates From Little Loligo Squid (Uroteuthis chinensis)

Research on the little loligo squid (Uroteuthis chinensis) protein hydrolyzed by papain and Flavourzyme and characterization of hydrolysates was carried out in this article. The optimum hydrolysis conditions of papain were obtained by orthogonal experiments, and the influence factors on the degree of hydrolysis such as enzyme/substrate ratio, hydrolysis time, pH, and temperature were investigated. The effect of Flavourzyme on the degree of hydrolysis was also studied. The characteristics of freeze-dried hydrolysates such as yield, moisture, nitrogen recovery, molecular mass distribution, and amino acid composition were determined. The results showed that papain and Flavourzyme could hydrolyze the little loligo squid protein efficiently, and the degree of hydrolysis was up to 25.82% under the optimum hydrolysis conditions. The average molecular mass of hydrolysates obtained with papain and Flavourzyme was 1,246 Da, and the low molecular mass peptides were the main fraction of hydrolysates. The yield, moisture, and nitrogen recovery of freeze-dried hydrolysates was 19.8, 4.4, and 74.2%, respectively. Compared with suggested patterns of amino acid requirements by the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO), the hydrolysates of the little loligo squid had high nutritional value, and was a potential nutritious supplement used in various food products.