Application of ELISA-based kit for detecting AOZ and determining its clearance in eel tissues

Furazolidone, an antibacterial drug that was once widely used in the livestock industry and aquaculture, is now prohibited in numerous countries. It is difficult to detect residual furazolidone because it is readily metabolized in animal tissues but, by using and liquid chromatography coupled with tandem mass spectrometry, its metabolite, 3-amino-2-oxazolidinone (AOZ) can be detected. Here we describe the validity of an enzyme-linked immunosorbent assay (ELISA) kit to detect AOZ in Japanese eel Anguilla japonica tissue. ELISA is capable of detecting AOZ at 1.0 μg/kg in an eel sample with excellent accuracy and precision. Our results show that ELISA is suitable for regulatory purposes and for studying the fate of AOZ residues in eel treated with furazolidone. To measure the persistence of AOZ in eel tissues, eels (1.4–6.5g) were immersed in tanks containing 2 and 10 mg furazolidone/L for 3 h, and then maintained in a tank supplying well water for the next 160 days. The half-lives of AOZ, calculated from the linear terminal part of the excretion curve, were 25.0 days in muscle and 21.6 days in liver from fish exposed to 2 mg/L furazolidone. In the eels treated with 10 mg/L furazolidone, by contrast, high levels of AOZ were detected in liver and muscle, but the half-lives of AOZ were similar to those in fish treated with 2 mg/L furazolidone. The half-lives of AOZ in eel tissues were prolonged by the condition of low water temperature.     

Beluga (Huso huso, Brandet 1869) bioenergetics under dietary methylmercury

Recently, there have been reports of increasing amounts of mercury (Hg) in muscles of beluga (Huso huso, Brandet 1869) in the Caspian Sea which exceeds its guideline level for food in the UK. Our intensive effort was to investigate the effects of dietary methylmercury (MeHg) on Beluga bioenergetics. Beluga juveniles were fed with four diets containing MeHg (control: 0.04 mg kg⁻¹; low: 0.76 mg kg⁻¹; medium: 7.88 mg kg⁻¹; and high: 16.22 mg kg⁻¹) for 70 days. There were significant differences in food consumption among the treatment groups. After 42 days, all individuals of the high dose died. After 35 and 70 days, all treatment groups (low, medium and high) showed a significant decline in their growth rate, unlike the control group. They also showed considerable lower specific growth rates (SGR) comparing to the control group. All treatment groups assimilated the dietary MeHg into their muscle tissue in a dose-dependent manner. Assimilation percent was significant among the treatment groups at days 35 and 70, but it was lower in the first 35 days than in the second 35 days. The data obtained from the dietary MeHg concentration and bioaccumulation rates were modeled for better natural resources management of the Caspian Sea.     

温度对奥尼罗非鱼受精卵孵化和仔鱼活力的影响

研究了温度对奥尼罗非鱼(Oreochromis niloticus×O.aureus)受精卵孵化和仔鱼活力的影响。在盐度为5不同温度(22、24、26、28、30、32和34℃)下,比较观察奥尼罗非鱼受精卵的培育周期、孵化周期、孵化率和畸形率。同时在以上不同温度条件下对初孵的奥尼罗非鱼仔鱼进行耐饥饿试验,测定其不投饵存活系数(Survivalactivity index,SAI)。结果表明:在温度为24~32℃,受精卵孵化率较高(84.3%~91%),温度高于34℃和低于22℃时,孵化率较低。温度与培育周期呈负相关关系,函数关系为y=0.3607x2-26.836x+553.5,R2=0.973。仔鱼生存适宜温度是24~30℃,最适的温度是24~26℃。温度为22℃时,SAI值分别为19.9,但是仔鱼发育的缓慢,部分仔鱼的身体色素一直没有出现,不适合仔鱼的培育。     

鲫肠道上皮细胞原代培养方法的研究

探讨了健康鲫(Carassius auratus)幼鱼肠道上皮细胞的原代培养方法。结果显示,用含有抗生素、胶原蛋白酶Ⅰ、EDTA和胶原蛋白酶Ⅳ组成的D-Hanks液消化无菌分离的鲫肠道可以获得大量细胞团及绒毛隐窝;用含有抗生素、胎牛血清(FBS)、表皮生长因子(EGF)、胰岛素的DMEM培养液进行培养,并根据肠道上皮细胞与成纤维细胞贴壁时间的差异进一步纯化,连续培养12d后可以得到纯化的肠道上皮细胞。     

乳山湾沉积物中酸挥发性硫化物(AVS)的分布变化特征

2005年12月和2006年3、6、9月,乳山湾滩涂底质环境调查中的16个站点的酸挥发性硫化物(AVS)含量的测定分析结果表明,表层沉积物中AVS具有明显的时、空变化。水平变化范围分别为:春季16·46~230·62mg/kg(干重,下同)、夏季33·65~568·48mg/kg、秋季23·49~350·69mg/kg、冬季15·77~190·96mg/kg,平均值分别为92·82、208·65、177·27和82·87mg/kg。对养殖区与非养殖区AVS含量进行比较,结果表明,养殖区明显高于非养殖区。在深度为0~20cm之间,AVS含量基本是随着深度的增加而增加。本文还就近几年乳山湾东流区表层底质中的AVS含量作了年际比较分析,结果表明,AVS含量年际变化不明显。     

苎麻新品种“华苎4号”选育研究

“华苎 4号”是从稀节巴品种自然杂交后代中选育出来的新品种。该品种产量高 ,在品系比较试验中平均亩产 2 2 6 .5kg ,比对照细叶绿品种增产 5 9.1 3% ,在湖北省区试中较对照增产 33.81 % :纤维品质优良 ,在品系比较试验中年均纤维细度 2 0 82支 ,在区试中经湖北省纤检所测试 ,年均纤维细度 2 2 39支 ;该品种植株高大整齐 ,出麻率特别高 (鲜皮出麻率和鲜茎出麻率分别在 1 4%和 5 %以上 ) ;“华苎 4号”的抗逆性强 ,高抗炭疽病 ,不感染花叶病 ,抗旱抗风性强 ,但耐渍性略差。     

粳稻柱头外露率QTL定位

【目的】柱头外露是影响杂交水稻制种的一个重要性状。本研究旨在初步鉴定控制柱头外露率的QTL。【方法】以高柱头外露率粳稻两系不育系大S×低柱头外露率热带粳稻品系D50的F_2群体及海南陵水、浙江杭州两地重复种植的F_(2:3)群体为材料,考查F_2群体及陵水、杭州两地两次重复F_(2:3)群体单边柱头外露率(PSES)、双边柱头外露率(PDES)和柱头总外露率(PES)。【结果】相关分析表明,单边柱头外露率、双边柱头外露率和柱头总外露率之间存在极显著的正相关。根据构建的大S×D50 F_2群体遗传连锁图谱,QTL分析检测到水稻柱头外露率QTL 21个,分布于第1、2、3、4、6、7和12染色体上,贡献率变幅为0.1%~57.6%,除个别贡献率极低的位点外,绝大部分QTL加性效应来自于高值亲本大S。其中位于第4染色体和第12染色体的两个位点q PDES4,q PES12在F_2和两次重复F_(2:3)群体中均检测到,贡献率分别达17.86%和16.98%。位于第3染色体的q PES3位点在陵水、杭州两次F_(2:3)群体中重复检测到,贡献率高达25.6%。【结论】检测到的QTL,有些与其他学者报道的处于同一位置,有些则是新的柱头外露率QTL。这些水稻柱头外露率QTL为今后柱头外露率基因精细定位、克隆、以及利用分子标记辅助选择(MAS)选育高柱头外露率粳型不育系提供理论依据。     

一个水稻小热休克蛋白的异源表达及寡聚特性分析

【目的】在前期研究中,本实验室已克隆了一个水稻小热休克蛋白基因(OsSHSP17.6),并发现该基因的表达明显受到热激和病毒侵染调控,表明该蛋白可能在逆境胁迫过程中起重要作用。本研究的目的在于进一步明确OsSHSP17.6的特性。【方法】在本研究中,进一步将该基因亚克隆至原核表达载体p ET-32a并导入大肠杆菌E.coli BL21(DE3)pLysS诱导表达,通过亲和层析的方法纯化了该重组蛋白,进一步用于非变性聚丙烯酰胺凝胶电泳和Western blotting分析。【结果】异源表达的重组OsSHSP17.6能减轻IPTG对宿主菌的毒害。非变性聚丙烯酰胺凝胶电泳和Western blotting分析显示纯化的重组OsSHSP17.6蛋白在体外能形成同源二聚体和寡聚体。【结论】这些结果支持OsSHSP17.6是一个有功能的分子伴侣蛋白并表明该蛋白可能通过形成同源寡聚体的方式参与逆境胁迫反应,这为进一步明确OsSHSP17.6的功能机制奠定基础。     

云南镇雄县金佛山方竹低效林改造效果

金佛山方竹是中国西南地区特有竹种,云南省镇雄县有金佛山方竹林面积为3.23万hm²。多年来,由于竹农过度采笋,而忽视竹林的科学经营,导致大面积竹林低产低效。文章分析了镇雄县金佛山方竹低效林的成因,提出了具体的改造措施,评估了低效林改造效果,以期为提升竹林质量、提高竹林生产力提供技术支撑。     

植保无人机喷施锌锰型水稻降Cd叶面阻控剂的飞行参数研究

应用植保无人机喷施叶面阻控剂有利于提高喷施均匀度、减少劳动力成本、提升作业效率。为规范植保无人机喷施叶面阻控剂田间作业,确保作业技术效果,本研究以大疆T16植保无人机为作业机,研究了喷施"美鑫隆"锌锰型叶面阻控剂以降低水稻Cd积累的最佳飞行高度、飞行速度和喷雾剂量等参数。结果表明,喷施锌锰型叶面阻控剂最佳降镉(Cd)效果的植保无人机作业参数分别为:喷施叶面阻控剂质量分数为12%,喷头总流量为3.6 L·min~(-1),飞行高度3 m,飞行速度5 m·s~(-1)。第二年在最佳参数下喷施叶面阻控剂,黄华占和湘晚籼13号的糙米Cd含量分别比对照下降了0.24 mg·kg~(-1)和0.12 mg·kg~(-1),降Cd率分别达到52.7%和62.1%(P0.01)。