核桃炭疽病高效生防菌株鉴定及抑菌活性

在对土壤有益微生物的分离、筛选中获得4株对核桃炭疽病菌具有较强抑制活性的拮抗细菌(编号分别为PF-1,PF-2,Bs-03,Bf-02)。通过对菌株的形态特征、染色反应、培养性状、生理生化特征、染色反应、培养性状、生理生化特性等试验项目,初步鉴定Bf-02为坚强芽孢杆菌(Bacillus firmus),Bs-03为枯草芽孢杆菌(Bacil-lus subtilis),PF-1为幼虫芽孢杆菌(Bacillus lacivae),PF-2为短芽孢杆菌(Bacillus brevis)。采用平板对峙培养法测定4株拮抗细菌对核桃炭疽病菌抑菌活性,4株拮抗细菌对核桃炭疽病菌具有较强的抑制活性,抑菌率均达到83%以上,抑制活性最强的是PF-2,抑菌率为88.47%,与其它3株拮抗细菌的抑菌率在P<0.05水平上具有显著性差异。其次为PF-1,抑菌率为86.11%,Bs-03和Bf-02的抑菌率在P<0.05水平上无显著性差异。     

草食性鱼种抑制凤眼莲生长的试验

通过严密的设计,在相同规格的16只网箱中,采用草鱼、杂交鱼[草鱼（6）和赤眼鳟（早）杂交繁育的F1]、三角鲂、赤眼鳟、异育银鲫和翘嘴红鲐等为试验对象,对凤眼莲生长的影响进行研究。结果表明：不同品种的鱼苗具有不同的控制凤眼莲的能力;在2．5～9．0cm范围内各鱼苗食用凤眼莲能力依次为：草鱼〉杂交鱼〉三角鲂〉赤眼鳟〉异育银鲫〉翘嘴红舶。     

感染鸡贫血病毒雏鸡接种新城疫疫苗后免疫保护效应及其机理研究

 雏鸡 1日龄人工感染鸡贫血病毒 (CAV) ,于 8日龄接种 L asota疫苗 ,免疫后 2 8d进行新城疫强毒 (v NDV)攻击 ,以同龄未感染 CAV和用 L asota疫苗免疫并经 v NDV攻毒雏鸡为对照 ,检测其免疫保护效应 ,胸腺和脾脏 T细胞数量及 T细胞增殖反应 ,法氏囊和脾脏 Ig G+、Ig M+、Ig A+抗体生成细胞数量 ,血清免疫球蛋白 Ig G、Ig M、Ig A含量 ,血凝抑制抗体 (HI)滴度等。结果表明 ,CAV人工感染并用新城疫 (ND)疫苗免疫雏鸡经 v NDV攻击后的免疫保护率为 6 0 % ,对照组雏鸡 v NDV攻击后免疫保护率为 10 0 % ,胸腺和脾脏 T细胞数量和 T细胞增殖反应、法氏囊和脾脏Ig G+ 、Ig M+ 、Ig A+ 抗体生成细胞数量、血清 Ig G、Ig M、Ig A含量及 HI抗体滴度 ,均较对照组雏鸡显著降低。说明感染鸡贫血病毒雏鸡接种新城疫疫苗后的免疫保护效应及免疫功能明显降低。     

植物单宁对烟草花叶病毒的抑制活性

测试了从11种植物提取的单宁对烟草花叶病毒(TMV)的抑制活性.结果表明:(1)任一植物的单宁质量浓度为5.000或2.500mg·mL-1时,与TMV混合10min后接种,其抑制率均达80%以上.(2)单宁质量浓度为5.000mg·mL-1时,与TMV混合后立即接种,其抑制率也均达80%以上,表明单宁与病毒粒体作用时间很短.(3)TMV与单宁混合,透析3d后,可恢复大部分侵染力;混合3d但未作透析处理,与混合10min的处理相比,抑制率下降,表明部分植物的单宁体外稳定性可能较差,与TMV粒体作用能力下降.(4)这11种植物的单宁对TMV体内抑制复制效果不明显.(5)大飞扬、杠板归、虎杖3种植物的单宁,在接种前先喷施心叶烟再接种TMV,可抑制病毒的初侵染;在接种前先喷施普通烟草K326再接种TMV,烟株发病期推迟3-8d.     

土壤重金属污染对蔬菜生长的抑制作用及其生态毒性

采用室内生长箱盆栽试验方法，进行了4种重金属铜、锌、铅、镉与蔬菜（株高、根伸长及株干重）生长的抑制－响应关系研究。结果表明，蔬菜株高与重金属浓度有较好的负相关性（r^2Cu=0.77,r^2Zn=0.96,r^2Pb=0.88,r^2Cd=0.98）；根长抑制率与重金属浓度相关性其次（r^2Cu=0.61,r^2Zn=0.88,r^2Pb=0.85,r^2Cu=0.78）。重金属对根伸长抑制作用最明显。蔬菜对铜的毒性响应比其它重金属敏感。蔬菜在重金属严重污染土壤中良好的生长状态，表明重金属通过蔬菜吸收可对人体健康造成潜在影响。     

不同水解程度丝素肽对黑色素生成抑制能力的研究

探讨了脱胶丝素经盐溶解后进行碱水解时 ,不同条件对丝素水解程度及不同水解程度丝素肽对蚕血黑色素生成的抑制能力的影响 .结果发现 ,温度对丝素的水解程度影响最大 ,时间其次 ,浓度的影响最小 ;丝素蛋白液未水解时 ,其对黑色素抑制率很低 ,只有 2 8.34% ,而丝素水解后 ,抑制率迅速提高到 4 8.95 % ,并且随着水解程度的加深不断提高 ,当氨基氮浓度达 0 .4 76 5g·L-1时 ,其对黑色素生成抑制率达最高值 6 7.14 % ;之后 ,随着水解程度的增加 ,其黑色素生成抑制率反而下降 .     

Inhibition of hirame rhabdovirus growth by RNA aptamers

RNA aptamers are artificial nucleic acids that specifically bind to a wide variety of targets. They are an effective tool for pharmaceutical research and development of antiviral agents. Here, we describe four Hirame rhabdovirus (HIRRV)‐RNA aptamers (H1, H2, H3 and H4) that we obtained from an in vitro process called the systematic evolution of ligands by exponential enrichment (SELEX). The HIRRV‐RNA aptamers specifically bind to HIRRV. Hirame natural embryo (HINAE) cells treated with virus and the RNA aptamer showed a decrease in appearance of cytopathic effect when compared with control (treated only with virus). Rhodovulum sulfidophilum was transformed with genes for the RNA aptamers, and the aptamers were detected in the culture medium, indicating that they were secreted from the cells. Thus, the recombinant R. sulfidophilum might be a powerful tool for the prevention of HIRRV in aquaculture.     

中国粳稻春江06抗白背飞虱的系谱分析

对中国粳稻春江06的抗白背飞虱特性进行系谱分析表明,春江06对白背飞虱的拒取食和杀卵抗性均来源于秀水620.秀水620的亲本中,只有秀水04具有较强的拒取食抗性,但没有杀卵抗性.在祥湖24中检测到明显的杀卵反应.亲本秀水04、单209和辐农709具有拒取食抗性,但测21没有.单209和辐农709的共同亲本农虎6号也具有拒取食抗性.然而,农虎6号、农垦58(日本粳稻)和老虎稻(中国粳稻地方品种)不具有拒取食抗性,在田间表现出感虫性.农虎6号、单209、辐农709和秀水04表现出稳定的田间抗性.春江06育种中的两个籼稻品种IR26和IR28高感白背飞虱,既无拒取食抗性,也无杀卵作用.     

响应曲面法优化美拉德反应以制备蘑菇酪氨酸酶活性抑制组分

MRPs作为天然抗褐变剂,可抑制引起果蔬酶促褐变的酪氨酸酶的酶活。为进一步优化美拉德反应以制备酪氨酸酶活性抑制组分,本研究采用响应面法对MRPs制备工艺进行研究。在单因素实验基础上,确定美拉德反应初始pH、反应温度、反应时间、底物浓度比(糖∶氨基酸)4个因素,设计4因素5水平的二次回归中心组合试验。经响应面法分析,为方便实际操作,确定最佳工艺条件为:初始pH为2.94,反应时间为1.9 h,反应温度为110.09℃,底物浓度比(糖∶氨基酸)为0.57。经实验验证,得出结果与理论值相对误差较小,故采用二次回归中心组合设计得到的最优MRPs制备条件参数准确可靠。     

Nitrous oxide emission measurement with acetylene inhibition method in paddy fields under flood conditions

Nitrous oxide (N₂O) emission from flooded rice paddy fields was continuously measured by the closed chamber method at an experimental plot in Thailand for a whole cultivation period. To characterize the N₂O emission with regard to the denitrification N loss, the C₂H₂ inhibition method was applied. Flood water on the soil greatly suppressed the N₂O emission. The N₂O emission was mitigated considerably by even a thin film of the flood water. The overall average N₂O emissions under flood conditions for one crop season (83 days) at the control site and the C₂H₂ treated site were 10.3 and 11.8 μg N m⁻² h⁻¹, respectively. The N₂O emission from the C₂H₂ treated site was consistently higher than that from the control site and the N₂O emission from both sites followed the same diurnal and seasonal variation pattern, indicating the effect of denitrification inhibition by the supplied C₂H₂. The N₂O emission enhanced along with temperature increase when NO₃–N concentration in the soil water was above 0.4 mg N l⁻¹ and soil temperature was above 24°C, suggesting specific temperature influence over the emission. The increase in NO₃–N concentration and temperature in the soil affected only the N₂O emission while the difference in the emission at the C₂H₂ treated site and the control site was not so much affected. It was suggested that most of the actively produced N₂O under higher NO₃–N concentration and temperature would likely to quickly emit to the atmosphere rather than to undergo further reduction to N₂.