RESPONSE OF GUANOSINE 5'-TRIPHOSPHATE CONCENTRATION TO NUTRITIONAL CHANGES AND ITS SIGNIFICANCE FOR BACILLUS-SUBTILIS SPORULATION
RESPONSE OF GUANOSINE 5'-TRIPHOSPHATE CONCENTRATION TO NUTRITIONAL CHANGES AND ITS SIGNIFICANCE FOR BACILLUS-SUBTILIS SPORULATION
复制标题
DOI：
10.1128/jb.146.2.605-613.1981
复制
发表时间：
1981-01-01
影响因子：
3.2
通讯作者：
FREESE, E
中科院分区：
文献类型：
--
作者：
LOPEZ, JM;DROMERICK, A;FREESE, E
研究了枯草杆菌严格菌株和松弛菌株在经常用来启动产孢子的条件下，GTP和P-核糖基-PP(P-核糖基-PP)库的变化。在从酪氨酸-谷氨酸转移到谷氨酸介质(Sterlini-Mandelstam Shift down)后，两个菌株的ATP和P-核糖-PP库都增加了；在严格菌株中，ppGpp[鸟苷3‘’-二磷酸5‘-二磷酸]和pppGpp[鸟苷3’‘-二磷酸5’-三磷酸]增加，GTP迅速下降，而在宽松菌株中，ppGpp和pppGpp仅略有增加，GTP仅缓慢和较少地下降。严格菌株孢子萌发较好，而宽松菌株孢子萌发较晚且较差。加入GMP合成酶抑制剂去氧核苷酸后，GTP进一步降低，并使松弛菌株产生良好的产孢量。在从葡萄糖-乳酸转移到乳酸介质(Ramaley-Burden Shift down)后，两个菌株的P-核糖基-PP(和GTP)池都减少了，表明嘌呤前体短缺。这种移位也引起了一种严格的反应，阻止了核苷酸的消耗，这从严格菌株中维持高浓度的ATP而在宽松菌株中没有显示出来。在延迟一段时间后，松弛菌株的GTP下降速度与严格菌株一样快，也同样有效地萌发孢子。在营养产孢剂中，严格菌株和松弛菌株在接近指数生长结束时暂时积累ppGpp和pppGpp，但效果较差。最终，两个菌株的P-核糖-PP池急剧减少。在所有情况下，产孢量的启动与GTP的显着降低有关。用一种阻止亮氨酰-tRNA充电的抗生素Granaticin表明，这种严格的反应抑制了IMP的XMP形成。它可以防止XMP在严格菌株的脱氧核嘌呤处理的培养物中积累，但不能在宽松菌株的培养物中积累。
The changes in the GTP and P-ribosyl-PP [phosphoribosyl pyrophosphate] pools in stringent and relaxed strains of B. subtilis were investigated under conditions frequently used to initiate sporulation. After a shiftdown from a Casamino Acid-glutamate to a glutamate medium (Sterlini-Mandelstam shiftdown), the pools of ATP and P-ribosyl-PP increased in both strains; in the stringent strain, ppGpp [guanosine 3''-diphosphate 5''-diphosphate] and pppGpp [guanosine 3''-diphosphate 5''-triphosphate] increased and GTP decreased rapidly, whereas in the relaxed strain, ppGpp and pppGpp increased only slightly and GTP decreased only slowly and less extensively. The stringent strain sporulated well; the relaxed strain sporulated late and poorly. Addition of decoyinine, an inhibitor of GMP synthetase, caused a further decrease of GTP and initiated good sporulation of the relaxed strain. After a shiftdown from a glucose-lactate to a lactate medium (Ramaley-Burden shiftdown), the pool of P-ribosyl-PP (and GTP) decreased in both strains, indicating a shortage of purine precursors. This shiftdown also caused a stringent response which prevented the consumption of nucleotides, as shown by the maintenance of ATP at a high concentration in the stringent strain but not in the relaxed strain. After a delay, the relaxed strain, in which GTP decreased as fast as in the stringent strain, sporulated also as efficiently. In nutrient sporulation medium the stringent strain and, less effectively, the relaxed strain accumulated ppGpp and pppGpp transiently towards the end of exponential growth. Eventually, the P-ribosyl-PP pool decreased drastically in both strains. In all cases the initiation of sporulation was correlated with a significant decrease of GTP. Granaticin, an antibiotic which prevents the charging of leucyl-tRNA was used to show that the stringent response inhibited the formation of XMP from IMP. It prevented the accumulation of XMP in decoyinine-treated cultures of the stringent strain but not in those of the relaxed strain.