VALU J A
Appl Microbiol. 1965 May;13(3):486-90. doi: 10.1128/am.13.3.486-490.1965.
Since washed cells of Lactobacillus leichmannii ATCC 7830 frequently showed erratic results in vitamin B(12) assays, a depletion technique was used to stabilize the inoculum. The method consisted of incubating the twice-washed cells at 37 C for 45 min in distilled water. Survival and growth studies indicated that the stabilizing procedure (i) did not affect cell numbers, (ii) was optimal for depleting possible carry-over of vitamin B(12) or other nutrilites and reserves, and (iii) brought about a phasing of the cells of the inoculum which underwent logarithmic growth immediately on inoculation. This minimal period (45 min) was the same when the cells were incubated in dextrose-water. Survival of the cells in physiological saline was greater than in distilled water, but a longer time was required for stabilizing the inoculum in saline, which precluded its use in routine work. The prepared inoculum showed an improvement over the washed inoculum in that readings between duplicate and triplicate tubes agreed closely and the standard curves were reproducible whether acidimetric or turbidimetric methods were followed. No erratic results were noted in more than 1 year of testing.
由于莱氏乳杆菌ATCC 7830的洗涤细胞在维生素B12测定中经常出现不稳定的结果，因此采用了一种耗尽技术来稳定接种物。该方法包括将洗涤两次的细胞在蒸馏水中于37℃孵育45分钟。存活和生长研究表明，稳定程序（i）不影响细胞数量，（ii）对于耗尽可能残留的维生素B12或其他营养物质及储备是最佳的，（iii）使接种物的细胞同步化，接种后立即进行对数生长。当细胞在葡萄糖水中孵育时，这个最短时间（45分钟）是相同的。细胞在生理盐水中的存活率高于在蒸馏水中，但在盐水中稳定接种物需要更长时间，这排除了其在常规工作中的使用。制备的接种物与洗涤后的接种物相比有改进，即重复管和三联管之间的读数非常一致，并且无论采用酸碱滴定法还是比浊法，标准曲线都是可重复的。在一年多的测试中未发现不稳定的结果。
