Singh R P, Setlow B, Setlow P
J Bacteriol. 1977 Jun;130(3):1130-8. doi: 10.1128/jb.130.3.1130-1138.1977.
We have determined the amounts of a number of small molecules and enzymes in the mother cell compartment and the developing forespore during sporulation of Bacillus megaterium. Significant amounts of adenosine 5'-triphosphate and reduced nicotinamide adenine dinucleotide were present in the forespore compartment before accumulation of dipicolinic acid (DPA), but these compounds disappeared as DPA was accumulated. 3-Phosphoglyceric acid (3-PGA) accumulated only within the developing forespore, beginning 1 to 2 h before DPA accumulation. Throughout its development the forespore contained constant levels of enzymes of both 3-PGA synthesis (phosphoglycerate kinase and glyceraldehyde-3-phosphate dehydrogenase) and 3-PGA utilization (phosphoglycerate mutase, enolase, and pyruvate kinase) at levels similar to those in the mother cell and the dormant spore. Despite the presence of enzymes for 3-PGA utilization, this compound was stable within isolated forespores. Two acid-soluble proteins (A and B proteins) also accumulated only in the forespore, beginning 1 to 2 h before DPA accumulation. At this time the specific protease involved in degradation of the A and B proteins during germination also appeared, but only in the forespore compartment. Nevertheless, the A and B proteins were stable within isolated forespores. Arginine and glutamic acid accumulated within the forespore in parallel with DPA accumulation. The forespore also contained the enzyme arginase at a level similar to that in the mother cell and a level of glutamic acid decarboxylase 2- to 25-fold higher than that in the mother cell, depending on when in sporulation the forespores were isolated. The specific activities of several other enzymes (protease active on hemoglobin, ornithine transcarbamylase, malate dehydrogenase, aconitase, and isocitrate dehydrogenase) in forespores were about 10% or less of the values in the mother cell. Aminopeptidase was present at similar levels in both compartments; threonine deaminase was not found in either compartment.
我们已经测定了巨大芽孢杆菌芽孢形成过程中母细胞区室和发育中的前芽孢内多种小分子和酶的含量。在吡啶二羧酸（DPA）积累之前，前芽孢区室中存在大量的腺苷5'-三磷酸和还原型烟酰胺腺嘌呤二核苷酸，但随着DPA的积累，这些化合物消失了。3-磷酸甘油酸（3-PGA）仅在发育中的前芽孢内积累，在DPA积累前1至2小时开始。在前芽孢的整个发育过程中，其3-PGA合成酶（磷酸甘油酸激酶和甘油醛-3-磷酸脱氢酶）和3-PGA利用酶（磷酸甘油酸变位酶、烯醇化酶和丙酮酸激酶）的水平保持恒定，与母细胞和休眠芽孢中的水平相似。尽管存在3-PGA利用酶，但该化合物在分离的前芽孢内是稳定的。两种酸溶性蛋白（A蛋白和B蛋白）也仅在前芽孢中积累，在DPA积累前1至2小时开始。此时，参与萌发过程中A蛋白和B蛋白降解的特异性蛋白酶也出现了，但仅在前芽孢区室中。然而，A蛋白和B蛋白在分离的前芽孢内是稳定的。精氨酸和谷氨酸与DPA积累同时在前芽孢内积累。前芽孢中还含有与母细胞中水平相似的精氨酸酶，以及比母细胞中高2至25倍的谷氨酸脱羧酶水平，这取决于在前芽孢形成过程中的何时进行分离。前芽孢中其他几种酶（对血红蛋白有活性的蛋白酶、鸟氨酸转氨甲酰酶、苹果酸脱氢酶、乌头酸酶和异柠檬酸脱氢酶）的比活性约为母细胞中值的10%或更低。氨肽酶在两个区室中的水平相似；苏氨酸脱氨酶在两个区室中均未发现。
