| 产品名称： | 叶酸干酪培养基；叶酸测定培养基（干酪乳杆菌法）、叶酸酪蛋白培养基 |
|---|---|
| 英文名称： | Folic Acid Casei Medium、BD282210、BD 282210 |
| 培养基类型： | 营养培养基 |
| 级别： | for microbiology |
| 品牌： | ELITE-MEDIA（艾礼培养基） |
| 产品目录号： | M350-01、M350-02 |
| 产品规格： | 100g、250g |
| 产品外观： | 浅黄色或麦秸色粉末，易形成软块。 |
| 灭菌后颜色与澄清度： | 溶液呈浅琥珀色，透明，基本无沉淀。 |
| 保存条件： | 密封，2-25°C保存。制备好的培养基2-8°C避光保存。 |
| 注意事项： | 避免摄入、吸入、皮肤接触。 |
| 相关产品： |
叶酸测定培养基（希氏肠球菌法） 叶酸培养基（AOAC法） |
产品描述：
叶酸干酪培养基(Folic Acid Casei Medium)，也叫叶酸酪蛋白培养基是叶酸测定培养基，利用干酪乳杆菌ATCC7469对血清中的叶酸含量进行微生物法测定。工作原理
维生素测定培养基用于水溶性维生素的微生物学测定。该方法中涉及3类培养基：1. 护理培养基：用于扩增、培养和护理培养物，保持培养物的活力和敏感性。
2. 接种培养基：处理培养物，然后立即接种到测定培养基上。
3. 测定培养基：含有检测菌生长所需的营养成分，只缺少待测B族维生素，用于定量测分析待测维生素。
检测用细菌有莱希曼氏乳杆菌（Lactobacillus leichmanni ATCC7830）、植物乳杆菌（Lactobacillus plantarum ATCC8014）、干酪乳杆菌（Lactobacillus casei ATCC7469）、希氏肠球菌（Enterococcus hirae ATCC8043）和其它必需维生素B的菌株。
该方法的测试菌株为干酪乳杆菌ATCC7469。叶酸培养基含有干酪乳杆菌生长所必需的除叶酸外所有营养成分。而叶酸是干酪乳杆菌ATCC7469生长所必需的B族维生素。
用途：
该培养基被推荐用于确定血清中的叶酸含量。配方与配制方法
| 组分 | (g/L) |
| 酸水解酪蛋白（不含维生素） | 10 |
| 葡萄糖 | 40 |
| 乙酸钠 | 40 |
| 磷酸氢二钾 | 1 |
| 磷酸二氢钾 | 1 |
| DL-色氨酸 | 0.2 |
| L-天冬酰胺 | 0.6 |
| L-胱氨酸盐酸盐 | 0.5 |
| 硫酸腺嘌呤 | 0.01 |
| 盐酸鸟嘌呤 | 0.01 |
| 尿嘧啶 | 0.01 |
| 黄嘌呤 | 0.02 |
| 吐温80 | 0.1 |
| 还原型谷胱甘肽 | 0.005 |
| 硫酸镁 | 0.4 |
| 氯化钠 | 0.02 |
| 硫酸亚铁 | 0.02 |
| 硫酸锰 | 0.015 |
| 核黄素（维生素B2） | 0.001 |
| 对氨基苯甲酸(PABA) | 0.002 |
| 盐酸吡哆辛 | 0.004 |
| 盐酸硫胺 | 0.0004 |
| 泛酸钙 | 0.0008 |
| 烟酸 | 0.0008 |
| 生物素 | 0.00002 |
| pH 6.7±0.1 |
1. 用100ml去离子水重悬9.4g本产品，加入50mg抗坏血酸。
2. 混合均匀，分装时使沉淀均匀分布。每个测定试管中分装5ml。
3. 加入标准样或待测样。用去离子水定容至10ml。
4. 121°C灭菌5min。立即冷却。
本产品配方与BD282210、BD 282210配方完全一致！
实验方法
Stock cultures of Lactobacillus casei ATCC 7469 are prepared by stab inoculation of Lactobacilli Agar AOAC. Following incubation at 35-37°C for 18-24 hours the tubes are stored in a refrigerator. Transfers are made at monthly intervals. Inoculum for assay is prepared by subculturing from stock culture of Lactobacillus casei ATCC 7469 into a tube containing 10 ml of Micro Vitamin Test Inoculum Broth or Lactobacilli Broth. After 24 hours incubation at 35-37°C, the cells are centrifuged, under aseptic conditions, and the supernatant liquid is decanted. The cells are then resuspended in 10 ml of sterile single strength Folic Acid Casei Medium, resedimented as before and washed one more time. Finally, the washed cells are resuspended in 10 ml of sterile single strength Folic Acid Casei Medium and diluted 1:100 with the same medium. One drop of this suspension is used to inoculate each of the assay tubes. 0.85% NaCl can be used instead of the single strength basal medium to wash and dilute the inoculum. A standard curve for each assay should be prepared, since the conditions of sterilization, temperature of incubation, etc, which influence the standard curve readings, cannot be duplicated exactly from time to time. The standard curve is obtained by using folic acid at levels of 0.0, 0.1, 0.2, 0.4, 0.6, 0.8 and 1 ng per assay tube (10 ml). Preparation of Folic Acid ConcentrationsDissolve 20 mg dried folic acid in 100 ml distilled water containing 20 ml ethanol. Adjust the pH of the solution to 10.0 with 0.1N NaOH to dissolve the acid and then adjust pH to 7.0 with 0.05N HCl. This solution contains 200 mcg folic acid per ml. Dilute 1 ml of this solution with 999 ml of distilled water to get 200ng per ml and finally, dilute 1 ml of this solution with 999 ml of Folic Acid Buffer A to get a standard solution containing 0.2 ng folic acid per ml. Use 0.0, 0.5, 1.0, 2.0, 3.0, 4.0 and 5 ml per assay tube.
Preservation of Serum Specimen
Allow the blood specimen to clot so as to separate the serum. Separate the serum into a clean dry tube and centrifuge to remove any blood cells present. Take care to avoid haemolysis of erythrocytes. Dispense 5 ml of serum sample into clean dry test tubes and add 25 mg ascorbic acid to each tube. Keep the tubes frozen below -20°C till assay.
Preparation of Serum Specimens
Thaw the serum containing ascorbic acid. Add 5 ml of this sample to 45 ml of rehydrated Folic Acid Buffer A . Incubate this serum - buffer solution at 37°C for 90 minutes and then autoclave at 15 lbs pressure (121°C) for 2.5 minutes. Remove the coagulated protein by centrifuging and transfer the supernatant to a clean, dry tube. This clear solution obtained is used as a sample in the folic acid assay. Procedure for determination of Total Folic Acid concentration in specimens.
Use 0.5, 1.0, 1.5 ml or other volumes of the prepared serum extracts as described earlier. Fill each tube with 5 ml Folic Acid Casei Medium and sufficient distilled water to give total volume of 10 ml per tube. Sterilize tubes at 15 lbs pressure (121°C) for 5 minutes. Cool the tubes and add one drop of inoculum to each assay tube. Turbidimetric reading should be made after 18-24 hours incubation at 35-37°C. Tubes are refrigerated for 15-30 minutes to stop growth before reading. The turbidometric readings are recorded at 620 nm. The amount of folic acid in the test samples can be determined by interpreting the results with the values obtained on the standard curve taking into consideration the dilution of sample. Extreme care should be taken to avoid contamination of media or glassware used for the assay. Detergent free clean glassware should be used. Even small amount of contamination by foreign material can be lead to erroroneus results.
