| 产品名称： | 抗生素测定培养基M；拉沙里菌素测定培养基 |
|---|---|
| 英文名称： | Antibiotic Assay Medium M |
| 培养基类型： | 非选择性培养基 |
| 级别： | for microbiology |
| 品牌： | ELITE-MEDIA（艾礼培养基） |
| 产品目录号： | M296-01、M296-02 |
| 产品规格： | 250g、500g |
| 产品外观： | 麦秸色粉末。 |
| 灭菌后颜色与澄清度： | 浅黄色略不透明凝胶。 |
| 保存条件： | 密封，2-25°C保存。 |
| 注意事项： | 避免摄入、吸入、皮肤接触。 |
| 相关产品： | -- |
产品描述：
抗生素测定培养基M（Antibiotic Assay Medium M，AOAC）作为底层琼脂，利用枯草芽孢杆菌ATCC6633（Bacillus subtilis ATCC6633），结合琼脂扩散法测定饲料中拉沙里菌素（Lasalocid）效价。本配方为AOAC推荐配方。用途：
抗生素测定培养基M被AOAC推荐用于微生物法测定测定饲料中拉沙里菌素效价。配方与配制方法
| 成分 | g/L |
|---|---|
| 磷酸氢二钾 | 0.69 |
| 磷酸二氢钾 | 0.45 |
| 酵母提取物 | 2.5 |
| 无水葡萄糖 | 10 |
| 琼脂 | 20 |
| 终溶液pH | 6.0± 0.2 |
配制方法：
1. 称取33.64g本产品，用1000ml纯水重悬。
2. 加热使培养基完全溶解。
3. 121°C 灭菌15min。
4. 冷却至45-50°C 时倒平板。
实验方法
Prepare slant culture of Bacillus subtillis (ATCC 6633) on Assay Medium No. 1 and incubate for 16-24 hours at 37°C. Wash the growth with sterile distilled water and transfer it to surface of Assay Medium No. 32 and incubate at 37°C for 7 days. Wash the growth with sterile distilled water. Heat to 65°C for 30 minutes in water bath. Centrifuge, decant the supernatant and resuspend the cells. Repeat this for 3 minutes in water bath. Dilute suspension with sterile distilled water (1 + 50) to read 20%T on sprectrophotometer at 530 nm before use.Use single inoculated agar layer. Optimum concentration of suspension of Bacillus subtillis is determined prior to assay to be added to Medium M to obtain inhibition zone of adequate size (17.5 ± 2.5 mm with 1.0 µg/ml). For actual assay add appropriate amount of suspension to sterile, molten medium M (pH 6.0). Mix and add 6 ml to each plate. Prepare plates 2.5 3 hours before use. Weigh 1.0 g premix. Transfer to flask and add 100 ml methanol. Shake vigorously for 3 minutes and dilute with methanol. Dilute 4 ml of this to 100 ml methanol. Further dilute 3 ml with 22 ml methanol and water to 100 ml (1 ml= ca/µg lasalocid Na/ml 25% methanol). Prepare final concentration of feed to 0.0075%. For more details refer AOAC.
Using lasalocid, sodium obtain standard response line, assay solution. Place cylinders on each plate and alternatively fill with reference concentration and other standard concentration. Incubate at 35-36°C. Calculate zone diameters of L (Low concentration giving measurable zone) and H (Highest concentration) of standard response line and connect with straight line. This corrected reference point is used for sample calculations. Average the 9 readings of reference concentration and 9 readings of assay solution. If assay solution gives larger average than reference concentration, add difference between them to reference point on standard response line. If the assay solution gives lower average than reference concentration, subtract the difference from reference point. Using the corrected value of assay solution, amount of antibiotic is determined.
