Gonzalez R, Islas L, Obregon A M, Escalante L, Sanchez S
Departamento de Biotecnologia, Universidad Nacional Autonoma de Mexico, Mexico D.F.
J Antibiot (Tokyo). 1995 Jun;48(6):479-83. doi: 10.7164/antibiotics.48.479.
The effect of ammonium on the fermentative production of gentamicin in Micromonospora purpurea has been studied using a chemically defined medium. Ammonium chloride concentrations ranging from 20 to 150 mM resulted in a proportional stimulation of growth and antibiotic formation. The use of other ammonium salts exerted a similar effect. Among the products of ammonium assimilation, glutamate and glutamine were able to exert the stimulatory effect. In addition, both amino acids reproduced the stimulation in resting cell systems of this microorganism and this result was not modified by the presence of chloramphenicol, eliminating a possible inductive action as the cause of this effect. The use of a glutamine synthetase inhibitor prevented antibiotic formation. This inhibition was reverted only by glutamine, suggesting that this amino acid was responsible of ammonium stimulation. Glutamine stimulation seems to be due to its ability to produce 2-deoxystreptamine and glucosamine, intermediates of the gentamicin biosynthetic pathway.
使用化学成分明确的培养基，研究了铵对紫色小单孢菌发酵生产庆大霉素的影响。氯化铵浓度在20至150 mM范围内会导致生长和抗生素形成呈比例地受到刺激。使用其他铵盐也产生了类似的效果。在铵同化产物中，谷氨酸和谷氨酰胺能够发挥刺激作用。此外，这两种氨基酸在该微生物的静止细胞系统中重现了这种刺激作用，并且氯霉素的存在并未改变这一结果，排除了可能的诱导作用是这种效应的原因。使用谷氨酰胺合成酶抑制剂会阻止抗生素的形成。这种抑制作用仅被谷氨酰胺逆转，表明这种氨基酸是铵刺激作用的原因。谷氨酰胺的刺激作用似乎是由于其产生2-脱氧链霉胺和葡糖胺的能力，这两种物质是庆大霉素生物合成途径的中间体。
