Mitra Anindita, Santra Subhas Chandra, Mukherjee Joydeep
School of Environmental Studies, Jadavpur University, Kolkata, 700 032, India.
Appl Microbiol Biotechnol. 2008 Sep;80(4):685-95. doi: 10.1007/s00253-008-1626-8. Epub 2008 Aug 5.
We examined the relationship between distribution of actinomycetes and antagonistic behaviour with the physico-chemical characteristics of the Sundarbans, off the Bay of Bengal, India. Soil/sediment samples were collected from three regions: near to the sea, intertidal regions and mangrove forests. For the enumeration of actinomycetes, four treatments combining dilution with distilled or sea water with or without heating followed by plating onto starch-casein, glycerol-arginine and starch-nitrate media were done. Dilution with seawater, heating and plating onto starch-casein yielded maximum number of actinomycetes. The highest number of actinomycetes was isolated from an intertidal region having alluvial soil and the lowest from a site containing sandy sediments. Antimicrobial activity was dependent upon seawater. Antimicrobial score of an actinomycetes strain was calculated allotting maximum points to the isolate showing activity against all the test bacteria, next lower point to the isolate showing activity against one less the total and so on. The antagonistic potential (AP) of a sampling site was the ratio of total antimicrobial score of the isolates and their number. The high AP sites were influenced by tides, while the low AP sites were not. Pearson's correlation between soil chemical parameters and microbiological parameters revealed soil nitrogen as the key factor determining the antagonistic activity.
我们研究了印度孟加拉湾沿岸孙德尔本斯地区放线菌分布及拮抗行为与理化特性之间的关系。从三个区域采集土壤/沉积物样本：近海区域、潮间带区域和红树林。为了对放线菌进行计数，采用了四种处理方法，即将样本用蒸馏水或海水稀释，加热或不加热，然后接种到淀粉酪蛋白培养基、甘油精氨酸培养基和淀粉硝酸盐培养基上。用海水稀释、加热并接种到淀粉酪蛋白培养基上得到的放线菌数量最多。从含有冲积土的潮间带区域分离出的放线菌数量最多，而从含有沙质沉积物的地点分离出的数量最少。抗菌活性取决于海水。计算放线菌菌株的抗菌得分时，对能抑制所有测试细菌的菌株给予最高分，对能抑制细菌种类比总数少一种的菌株给予次高分，依此类推。采样点的拮抗潜力（AP）是分离菌株的总抗菌得分与其数量的比值。高AP值的采样点受潮汐影响，而低AP值的采样点则不受影响。土壤化学参数与微生物参数之间的皮尔逊相关性表明，土壤氮是决定拮抗活性的关键因素。
