Isolation and structure elucidation of aerial mycelium-inhibitory substance in actinomycetes and differentiation mechanism of aerial mycelia

1.白黑链霉菌气生菌丝体抑制物质的研究白黑链霉菌在Bennet培养基中培养滤液用乙酸乙酯在pH 3条件下萃取，得到乙酸乙酯可溶性酸性组分。提取物经硅胶柱层析和pTLC纯化，ODS-HPLC在215 nm处紫外吸收峰的指引下进行分离。在室温7.8min处的峰显示出对气生菌丝体的抑制活性，但经ODS-HPLC后活性不完全，经光谱分析确定其活性物质为苯乙酸。在室温4.7分钟的峰馏分添加到苯乙酸中恢复了完全的气生菌丝体抑制。在Rt 4.7 min下的协同物质被鉴定为4-羟基苯甲醛。由于苯乙酸是苯丙氨酸的代谢产物，因此检查了其他相关代谢产物的气生菌丝体抑制活性。结果表明，苯乙胺和苯乙醛的活性比苯丙氨酸本身强。sp.by羟基苯甲醛的构效关系也进行了研究。2.卡巴霉素产量的提高卡巴霉素是本课题组从轮枝链霉菌中分离得到的一种气生菌丝体抑制物质。为了实现卡巴霉素的大规模生产，我们对发酵条件进行了改进。利用与卡唑霉素类似的咔唑核的卡唑霉素抗生素生产培养基，并添加消泡剂，卡唑霉素的产量提高了56倍。3.气生菌丝体调节物质产生菌的筛选本实验室对气生菌丝体抑制或诱导物质产生菌进行了调查。尚未发现气生菌丝抑制物产生菌，但发现3株气生菌丝诱导物产生菌。

1.Aerial mycelium-inhibitory substance in Streptomyces alboniger Culture filtrate of S.alboniger in Bennet's medium was extracted with EtOAc at pH3 to give EtOAc soluble acidic fraction. The extract was purified by silica gel column and pTLC,and then fractionated by ODS-HPLC with the guidance of UV absorption at 215 nm. The peak at Rt 7.8 min showed aerial mycelium-inhibitory activity, however its activity became incomplete after ODS-HPLC.The active substance was identified as phenylacetic acid by spectral analysis. Addition of the peak fraction at Rt 4.7 min to phenylacetic acid recovered complete aerial mycelium inhibition. The synergistic substance at Rt 4.7 min was identified as 4-hydroxybenzaldehyde. Since phenylacetic acid is a metabolite of phenylalanine, the aerial mycelium-inhibitory activity of other related metabolites were examined. As a result, phenylethylamine and phenylacetaldehyde showed stronger activity than phenylalanine by itself. The structure-activity relationships of 4-hydroxybenzaldehyde was also examined.2.Improvement of carbazomycinal production Carbazomycinal is an aerial mycelium-inhibitory substance isolated from Streptoverticillium sp.by our group. For the mass production of carbazomycinal, we improved cultured conditions. Use of the production medium of carbazomycin antibiotics, which have carbazole nucleus similarly to carbazomycinal, and addition of antifoaming agentresulted in 56-fold yield of carbazomycinal.3.Screening of the strain that produce aerial mycelium-regulatory substance The strain that produce aerial mycelium-inhibitory or-inducing substance was surveyed in the culture collection of our laboratory. We have not found aerial mycelium inhibitor producing strain yet, but could found 3 strains that produce aerial mycelium-inducing substance.