SHIGELLA-FLEXNERI INHIBITION BY ACETIC-ACID
SHIGELLA-FLEXNERI INHIBITION BY ACETIC-ACID
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DOI：
10.1128/iai.8.1.91-97.1973
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发表时间：
1973-01-01
影响因子：
3.1
通讯作者：
HENTGES, DJ
中科院分区：
文献类型：
--
作者：
BASKETT, RC;HENTGES, DJ
在化学成分确定的培养基中，乙酸对福氏志贺菌的抑制程度取决于培养基中未解离乙酸的浓度。在本实验条件下，未解离乙酸完全抑制S.弗氏增殖约为0.0018 M。培养后将培养基的pH从6.0调整到7.0，使未解离酸的浓度降低了10倍，完全逆转了抑制作用，S. Flexneri获得了与其在不含乙酸的培养基中的种群相当的存活种群。研究了乙酸对细胞过程的影响。酸干扰细胞内积累的葡萄糖和谷氨酸，但不干扰磷酸盐的积累。葡萄糖类似物3-O-甲基-D-葡萄糖，其被S.使用Flexneri但未代谢的葡萄糖来确定抑制是否是由于通过抑制葡萄糖代谢干扰渗透或干扰细胞内积累而导致的。乙酸不干扰S对葡萄糖类似物的摄取。flexneri，表明抑制可能涉及干扰代谢。从存在和不存在乙酸的无细胞浸提液的呼吸研究中获得了该结论的进一步证据。在没有渗透屏障的情况下，乙酸对氧摄取的抑制表明是代谢阻滞，而不是渗透干扰。在pH 6.0和7.0时，无细胞提取物对氧摄取的抑制作用均发生，表明酸的解离程度对细胞内物质代谢的干扰并不重要。解离度是重要的，但是，关于吸收乙酸的S。整个细胞对未解离形式的乙酸比解离形式的乙酸更具有渗透性。数据表明，当乙酸被S.福氏杆菌干扰细胞的葡萄糖代谢。
The degree ofShigella flexneriinhibition by acetic acid in a chemically defined medium was dependent upon the concentration of undissociated acetic acid in the medium. Under the conditions of the experiments, the critical concentration of undissociated acetic acid that completely inhibitedS. flexnerimultiplication was approximately 0.0018 M. Adjustment of the medium from pH 6.0 to 7.0 after incubation, which reduced the concentration of undissociated acid 10-fold, completely reversed inhibition, andS. flexneriattained a viable population equivalent to its population in medium without acetic acid. The effects of acetic acid on cellular processes were also studied. The acid interfered with the intracellular accumulation of glucose and glutamic acid but did not interfere with the accumulation of phosphate. The glucose analogue 3-o-methyl-D-glucose, which is taken up byS. flexneribut not metabolized, was used to determine if inhibition resulted from interference with permeation or interference with intracellular accumulation through inhibition of glucose metabolism. Acetic acid did not interfere with the uptake of the glucose analogue byS. flexneri, indicating that inhibition probably involves interference with metabolism. Further evidence for this conclusion was obtained from respiration studies with cell-free extracts in the presence and absence of acetic acid. Inhibition of oxygen uptake by acetic acid in the absence of a permeability barrier suggested a metabolic block rather than interference with permeation. The inhibition of oxygen uptake by cell-free extracts occurred at both pH 6.0 and 7.0, indicating that the degree of dissociation of the acid is unimportant regarding interference with metabolism by intracellular material. The degree of dissociation is important, however, regarding uptake of acetic acid byS. flexneri.Whole cells were more permeable to the undissociated form of acetic acid than to the dissociated form. The data indicate that acetic acid, when taken up byS. flexneri, interferes with the metabolism of glucose by the cells.