Bacterial attachment is influenced by the cell surface, attachment media and other environmental factors. Bacterial community composition involved in biofilm formation in extremely high rainfall areas like Cherrapunje...Bacterial attachment is influenced by the cell surface, attachment media and other environmental factors. Bacterial community composition involved in biofilm formation in extremely high rainfall areas like Cherrapunjee has not been reported. The present study was undertaken to characterize bacteria involved in biofilm formation on different substrata in water bodies of Cherrapunjee, the highest rainfall receiving place on planet earth and to assess if the continuous rainfall has an effect on nature and colonization of biofilm bacteria. We developed the biofilm bacteria on stainless steel and glass surfaces immersed in water bodies of the study sites. Isolation of biofilm bacteria were performed on different culture media followed by estimation of protein and carbohydrate content of bacterial exopolysaccharides. 16S rRNA gene sequences were amplified for molecular characterization. The results showed that the biofilm bacterial diversity in water bodies of Cherrapunjee was influenced by substratum and was observed more in stainless steel than glass surface. Scanning electron microscopy images revealed that biofilm microstructure may represent a key determinant of biofilm growth and physiology of associated bacteria. The overall protein content of the extracted EPS of all the isolates were relatively higher than the carbohydrate content. Diverse bacteria proliferated on the substrata regardless of each other's presence, with more diverse bacteria colonizing the substrata on 7th day compared to 15th day of incubation. The biofilm bacteria compositions in the highest rainfall receiving habitat were not distinctly different from reports available, hence not unique from other water bodies.展开更多
As part of a long time analysis to examine the ecological impacts of heavy rain coupled to soil degradation, soil fungal communities from two closely spaced sites bearing distinct ecology—one receiving heaviest rainf...As part of a long time analysis to examine the ecological impacts of heavy rain coupled to soil degradation, soil fungal communities from two closely spaced sites bearing distinct ecology—one receiving heaviest rainfall but degraded patch on earth and the other pristine sacred grove forest were investigated over a period of three years. Cherrapunji besides being highest rainfall receiving area, is characterized by complete deforestation and soil erosion with sparse grasses forming the surface growth, whereas the sacred forests are conserved in their pristine nature due to religious beliefs of the indigenous tribes. The effect of deforestation and land degradation on soil microbes, soil organic carbon, soil nitrate nitrogen, soil pH, soil temperature, and fungal CFU/g were investigated from the two contrasting sites. The sites showed great variability in physical and chemical parameters including soil composition, temperature, pH, soil carbon, nitrogen content, water availability and enzyme activities. The population count of fungi was higher in sacred forest soil than degraded land of Cherrapunji. In both soil types, Penicillium perpurogenum markedly dominated and the co-dominant species (Aspergillus sp., Fusarium sp. and Trichoderma sp.) were common in both virgin and degraded soils. A total of 63 species were identified during the study period. The species composition between the two sites showed some variation as Syncephalastrum sp., S. chartarum, Gliocladium sp., Eupenicillium osmophilum and Eurotium sp. were not present in Cherrapunji. The undisturbed sacred forest fungal communities had significantly higher Simpson, Shannon and evenness indices than that of degraded soil of Cherrapunji. The prolonged anthropogenic activity in the area leading to degradation coupled with heavy rainfall has decreased the diversity level of fungal communities and masked the pristine differentiating effect of soil on the fungal community.展开更多
文摘Bacterial attachment is influenced by the cell surface, attachment media and other environmental factors. Bacterial community composition involved in biofilm formation in extremely high rainfall areas like Cherrapunjee has not been reported. The present study was undertaken to characterize bacteria involved in biofilm formation on different substrata in water bodies of Cherrapunjee, the highest rainfall receiving place on planet earth and to assess if the continuous rainfall has an effect on nature and colonization of biofilm bacteria. We developed the biofilm bacteria on stainless steel and glass surfaces immersed in water bodies of the study sites. Isolation of biofilm bacteria were performed on different culture media followed by estimation of protein and carbohydrate content of bacterial exopolysaccharides. 16S rRNA gene sequences were amplified for molecular characterization. The results showed that the biofilm bacterial diversity in water bodies of Cherrapunjee was influenced by substratum and was observed more in stainless steel than glass surface. Scanning electron microscopy images revealed that biofilm microstructure may represent a key determinant of biofilm growth and physiology of associated bacteria. The overall protein content of the extracted EPS of all the isolates were relatively higher than the carbohydrate content. Diverse bacteria proliferated on the substrata regardless of each other's presence, with more diverse bacteria colonizing the substrata on 7th day compared to 15th day of incubation. The biofilm bacteria compositions in the highest rainfall receiving habitat were not distinctly different from reports available, hence not unique from other water bodies.
文摘As part of a long time analysis to examine the ecological impacts of heavy rain coupled to soil degradation, soil fungal communities from two closely spaced sites bearing distinct ecology—one receiving heaviest rainfall but degraded patch on earth and the other pristine sacred grove forest were investigated over a period of three years. Cherrapunji besides being highest rainfall receiving area, is characterized by complete deforestation and soil erosion with sparse grasses forming the surface growth, whereas the sacred forests are conserved in their pristine nature due to religious beliefs of the indigenous tribes. The effect of deforestation and land degradation on soil microbes, soil organic carbon, soil nitrate nitrogen, soil pH, soil temperature, and fungal CFU/g were investigated from the two contrasting sites. The sites showed great variability in physical and chemical parameters including soil composition, temperature, pH, soil carbon, nitrogen content, water availability and enzyme activities. The population count of fungi was higher in sacred forest soil than degraded land of Cherrapunji. In both soil types, Penicillium perpurogenum markedly dominated and the co-dominant species (Aspergillus sp., Fusarium sp. and Trichoderma sp.) were common in both virgin and degraded soils. A total of 63 species were identified during the study period. The species composition between the two sites showed some variation as Syncephalastrum sp., S. chartarum, Gliocladium sp., Eupenicillium osmophilum and Eurotium sp. were not present in Cherrapunji. The undisturbed sacred forest fungal communities had significantly higher Simpson, Shannon and evenness indices than that of degraded soil of Cherrapunji. The prolonged anthropogenic activity in the area leading to degradation coupled with heavy rainfall has decreased the diversity level of fungal communities and masked the pristine differentiating effect of soil on the fungal community.
