市售农残速测试剂盒对5种有机磷农药的敏感性评价

为了对商品化农残速测试剂盒进行评价,全面了解市售农残速测试剂盒的质量,本研究采用市售的6个品牌农残速测试剂盒,在2种情况下（提取液取用2.5 mL和3 mL）对甲拌磷、蝇毒磷、二嗪磷、对硫磷、久效磷进行敏感性测定,根据5种农药在5个浓度水平下的测定结果,绘制6个品牌的试剂盒的抑制率对农药浓度的效应曲线并用抑制率和农药浓度之对数进行线性拟合、计算出相关系数、IC₅₀和IC₁₀,根据IC₁₀对各种试剂盒对每种农药的敏感性进行比较并以此判定试剂盒的优劣。结果表明同一种试剂盒对不同的农药、不同的试剂盒对同一种农药的敏感性均不同;抑制率和农药浓度对数相关性较好的试剂盒其相关系数R²分别为0.4835~1（提取液取用2.5 mL）和0.6602~1（提取液取用3 mL）,IC₁₀分别为2.01×10^-4~3.78 mg/kg（提取液取用2.5 mL）和3.92×10^-3~3.36 mg/kg（提取液取用3 mL）;6种试剂盒对甲拌磷均不敏感,除了A试剂盒外其他试剂盒在5个浓度水平下抑制率均为0。根据所测试的5种农药,将试剂盒分为3个等次,D试剂盒最优,其次是C和E,第三是A、B和F。建议国标和行标修改50%或者70%的判定阈值。     

金针菇DNA提取方法比较

[目的]筛选有效的金针菇DNA提取方法。[方法]以培养的金针菇菌丝体为材料,分别采用CTAB法和试剂盒法提取金针菇DNA,并用琼脂糖凝胶电泳法和分光光度法检测所提取DNA样液的浓度与纯度。[结果]分光光度结果及电泳鉴定表明CTAB法提取的DNA产量较大但杂质多,试剂盒法提取的DNA产量小但杂质少。[结论]CTAB法和试剂盒法均可用于金针菇DNA的提取,如后续试验对提取的DNA纯度没有特别要求,可用CTAB法替代试剂盒法。     

龙井茶机械化加工配套技术的开发研究

通过对两种主要龙井茶加工工艺,三种辉锅方式,手工辅助辉锅作对照的比较分析,结果表明：两种工艺流程以第二条加工工艺为佳,即经理条后的加工工艺优于未经理条工艺,两种工艺手工辅助辉锅方式所制干茶差异不明显;辉锅试验结果表明：八角滚筒机优于其他两种辉锅设备,也优于手工辅助辉锅;最佳辉锅参数为组合2,即投叶量3.5～4 kg,160℃25 min＋200℃15 min。     

新孢子虫病rELISA抗体检测试剂盒的应用

[目的]研发一种成熟稳定的新孢子虫病rELISA抗体检测试剂盒.[方法]在新孢子虫病rELISA检测方法建立的基础上,组装检测新孢子虫病的rELISA抗体检测试剂盒,对试剂盒的敏感性、保存期、特异性和重复性进行评价,并与两种商品化试剂盒进行对比试验,应用自制的试剂盒检测来自新疆各地州新孢子虫疑似病例区血清,共1329份.[结果]成功组装了新孢子虫病rELISA抗体检测试剂盒,且该试剂盒敏感性高、保存期长、特异性强、重复性较好.与两种进口商品化诊断试剂盒比较,其符合率均在90;以上.在1 329样品血清中157份是阳性,其平均阳性率为11.8;.[结论]该试剂盒可以取代商品化试剂盒进行新孢子虫病诊断,为新孢子虫病的防治工作提供技术和产品支撑.     

一种多尺度纹理主频的检测与分割

介绍了一种对含有多种纹理结构的图像的纹理主频检测——香农小波包分解的纹理主频检测 ,然后利用 Gabor滤波器确定主频 ,最后应用边缘提取实现纹理分割     

滚筒干燥条件对荞麦雪花片质构特性的影响

考察了不同滚筒温度、滚筒转速、料液比对滚筒干燥工艺制得的荞麦雪花片质构特性的影响。研究结果表明,当滚筒温度由135℃增加到165℃时,荞麦雪花片质构特性值增大显著,每个参数都增加了70%左右;当滚筒转速由2 r·min^-1增加到4 r·min^-1时,荞麦雪花片坚实度增加了23.6%,稠度增加了11.6%,粘聚性增加了44.7%,粘度指数增加了30.8%;当料液比从1:1增加到1:1.4时,荞麦雪花片质构特性值都增大了20%,且滚筒温度、转速及料液比与质构特性的相关性强,相关系数R2都在0.96到1.0之间。本研究对不同工艺条件下荞麦雪花片质构特性的变化进行了理论分析,通过分析推测荞麦淀粉糊化过程中结构的变化及荞麦雪花片内部蜂窝结构的变化是导致荞麦雪花片质构特性变化的原因。     

Vitrification of sperm from marine fish: effect on motility and membrane integrity

Our goal was to develop a standardized approach for sperm vitrification of marine fish that can be applied generally in aquatic species. The objectives were to: (i) estimate acute toxicity of cryoprotectants over a range of concentrations; (ii) evaluate the properties of vitrification solutions (VS); (iii) evaluate different thawing solutions and (iv) evaluate sperm quality after thawing by examination of motility and membrane integrity. Sperm were collected from red snapper (Lutjanus campechanus), spotted seatrout (Cynoscion nebulosus) and red drum (Sciaenops ocellatus). A total of 29 combinations of cryoprotectants were evaluated for toxicity and glass formation. Samples were loaded onto 10‐μL polystyrene loops and plunged into liquid nitrogen. There was a significant difference (P < 0.05) in post‐thaw motility among VS and among species when using the same VS. The sperm in VS of 15% DMSO + 15% ethylene glycol + 10% glycerol + 1% X‐1000^? + 1% Z‐1000^? had an average post‐thaw motility of 58% and membrane integrity of 19% for spotted seatrout, 38% and 9% for red snapper, and 30% and 19% for red drum. Adaptations by marine fish to higher osmotic pressures could explain the survival in the high cryoprotectant concentrations. Vitrification offers an alternative to conventional cryopreservation.     

Effects of dietary thyroid hormones on the red drum (Sciaenops ocellatus)

Four separate 8-week feeding trials were conducted to assess the effects of supplementing semipurified diets with either triiodothyronine (T₃) or thyroxine (T₄) at 0, 2, 10, and 50 mg/kg on growth and body composition of juvenile red drum (Sciaenops ocellatus) held in artificial brackish water (6‰) and artificial seawater (32‰). At both levels of salinity, increasing doses of T₃ resulted in fish with reduced weight gain, feed efficiency, condition factor (weight × 100/length³), and muscle ratio (muscle weight × 100/body weight), as well as a lighter body color. Significant (p < 0.05) effects of T₃ on the proximate composition of whole body, liver, and muscle were variable, generally reflecting decreased lipid and protein storage in liver and muscle, respectively. The two highest doses of T₃ given to seawater adapted fish increased survival. Dietary T₄ supplementation had no distinctive effects on appearance, growth or proximate body composition. These results indicate that whereas T₃ may function to regulate protein and lipid metabolism in red drum, dietary supplementation with T₃ leads to a hyperthyroidism-induced catabolic state. The elevated endogenous thyroid hormone levels found in fish fed optimal diets may thus adequately supply tissue needs during juvenile growth.     

美国红鱼游泳体能分配模型及其在海区选址中的应用

以深水网箱养殖的美国红鱼为研究对象,通过研究其游泳时主要能量物质和代谢产物的变化规律,构建美国红鱼的游泳体能分配模型,最后结合特定的潮流规律,建立养殖海区最大潮流选择的理论方法。结果显示,美国红鱼游泳过程中,血糖浓度会显著提高,肌糖原有少量减少,肝糖原会显著降低,鱼类游泳接近疲劳时,肝糖原浓度亦接近耗尽;美国红鱼以较高速度游泳过程中,血乳酸和肌乳酸浓度会有较明显的增加,表明美国红鱼游泳过程伴随着无氧呼吸和有氧呼吸两种能量物质代谢过程。本实验提出以肝糖原浓度作为判定鱼类持续游泳能力的重要指标,并建立了基于肝糖原储能消耗的美国红鱼游泳体能分配模型。最后基于美国红鱼体能分配模型,结合养殖海区潮流规律,提出了美国红鱼养殖海区最大潮流流速选择的计算方法。研究表明,本实验提出的鱼类游泳体能分配模型构建方法以及鱼类养殖海区潮流选择论证方法,可为相关研究提供新的途径,为深水网箱、浅海围网等海洋养殖模式的海区潮流选址提供科学的参考依据。     

A preliminary study on the effects of dietary supplementation of brewers yeast and nucleotides, singularly or in combination, on juvenile red drum (Sciaenops ocellatus)

This study was designed to evaluate the effects of dietary supplementation with brewers yeast (Brewtech^®) and nucleotides (Optimûn), either singularly or in combination, on red drum growth, body composition, stress responses and possible resistance to Amyloodinium ocellatum infection. Juvenile red drum (～1 g initially) fed practical fish‐meal‐based diets for 6 weeks had similar weight gain regardless of whether the diet was unsupplemented (basal) or supplemented with brewers yeast (2% of diet), nucleotides (Optimûn at 0.2% of diet) or both brewers yeast (2% of diet) and nucleotides (Optimûn at 0.2% of diet). Dietary effects on hepatosomatic index, intraperitoneal fat ratio or whole‐body composition were not significant, except that fish fed the singular nucleotide supplement had a significantly higher whole‐body lipid content compared with fish fed the basal diet. No significant dietary effects on cortisol response were observed after a 15 min confinement stress test perhaps because of the extreme variation among individual fish. Subsequently, in situ challenge by co‐habitation with A. ocellatum caused 100% mortality regardless of dietary treatment within a 48 h period. It is concluded that dietary supplementation of brewers yeast and nucleotides did not promote enhanced growth or improved cortisol response and resistance to uncontrolled amyloodiniosis in juvenile red drum, at least at the tested dosages.