改进型拟态弧菌选择性鉴别培养基的研制

Improvement of a selective differential medium for Vibrio mimicus

旨在研究一种更适用于拟态弧茵快速筛检的改进型选择性鉴别培养基。根据拟态弧茵的特殊生态、营养、代谢、抵抗力等多方特点，并基于保留拟态弧茵选择性鉴别培养基（VmDM）的优点，改进其不足，分析研究并设计了改进型拟态弧茵选择性鉴别培养基（imVmDM）。继而对imVmDM的特异性、显色效果、阳性检出率、灵敏度和准确性进行了与VmDM和TCBS的对此评价。结果显示，培养18～24h，在imVmDM上，拟态弧茵菌落呈紫色，其他致病茵菌落呈黄色或不生长，色差对比显著；而在VmDM上，拟态孤菌茵落呈绿色，与培养基颜色相近；TCBS不能区分拟态孤茵与其余多种致病性弧菌。imVmDM与VmDM、TCBS的检出限都为101cfu／mL，但污染有非拟态弧茵时，imVmDM的特异性、准确性和显色效果更好。并且LimVmDM有效降低了检测成本，每个平板的配制价格由VmDM的5．58元降至0．33元。因此，imVmDM更适用于水产品中拟态弧菌的快速筛检，特别是大量样品的检测，能很大程度地降低检测成本，具有良好的市场应用前景。

Microstructure resulted from thermomechanial processing for an ultrahigh strength microalloyed steel 30Cr3SiNiMoVA （30Cr3） was characterized using optical and scanning electron microscopy in order to optimize parameters in the processing to obtain required properties. Tensile properties and work hardening behavior were analyzed for the steel tempered at different temperatures in the thermomechanial routes. The mierostructure of the steel after spinning deformation and tempering at 400℃ exhibits a better combination of strength and toughness owing to its fine tempered ferrite matrix and precipitation of dispersed carbide. Plastic deformation results in high density dislocations in microalloyed steel 30Cr3 by the thermomechanial treatment, which improves the precipitation of carbides in the matrix to rise the tension strength, however, overgrowth of the carbides after the tempering at temperature higher than 400 ℃ decreases the tension property because of the vanishing of carbide dispersion-strengthening. The optimized tempering temperature of 400 ℃ is recommended for thermomechanically treated 30Cr3 steel based on the experiment.