The response of bacteria to various carbohydrates in the deep-sea sediments and the Antarctic soils was investigated using cellulose, chitin, and olive oil. It was found that the carbohydrates significantly increased ...The response of bacteria to various carbohydrates in the deep-sea sediments and the Antarctic soils was investigated using cellulose, chitin, and olive oil. It was found that the carbohydrates significantly increased the corresponding specific ectoenzyme activity （β- glucosidase, β-N-acetylglucosaminidase, lipase） in the samples from deep-sea sediments. In the case of Antarctic soil samples, the cellulose or olive oil amendments had minor or no effect on β-glucosidase or lipase activity, except the chitin which stimulated β- N-acetylglucosaminidase production. The responses of the bacteria in the deep-sea sediment sample WP02-3 and the Antarctic soil sample CC-TY2 towards the chitin amendment were further analyzed. Chitin amendments were shown to stimulate the ectoenzyme activity in all the tested sediments and the soils. The bacterial response before and after the carbohydrates amendments were compared by denaturing gradient gel electrophoresis and quantitative competitive polymerase chain reaction. Significant changes were found in the structure and density of the bacterial community in the deep sea sediments as compared to the Antarctic soil sample, where the effects were relatively lower. There was no change in the bacterial population in both studied samples in response to carbohydrates amendments. These data indicate that the bacterial communities in the oligotrophic deep-sea sediments are more dynamic than that in the Antarctic soils as they respond to the nutrient sources efficiently by regulation of ectoenzyme activity and/or changing community structure.展开更多
Human mesenchymal stem cells(MSCs)are a rare population of non-hematopoietic stem cells with multilineage potential,originally identified in the bone marrow.Due to the lack of a single specific marker,MSCs can be reco...Human mesenchymal stem cells(MSCs)are a rare population of non-hematopoietic stem cells with multilineage potential,originally identified in the bone marrow.Due to the lack of a single specific marker,MSCs can be recognized and isolated by a series of features such as plastic adherence,a panel of surface markers,the clonogenic and the differentiation abilities.The recognized role of MSCs in the regulation of hemopoiesis,in cell-degeneration protection and in the homeostasis of mesodermal tissues through their differentiation properties,justifies the current interest in identifying the biochemical signals produced by MSCs and their active crosstalk in tissue environments.Only recently have extracellular nucleotides(eNTPs)and their metabolites been included among the molecular signals produced by MSCs.These molecules are active on both ionotropic and metabotropic receptors present in most cell types.MSCs possess a significant display of these receptors and of nucleotide processing ectoenzymes on their plasma membrane.Thus,from their niche,MSCs give a significant contribution to the complex signaling network of eNTPs and its derivatives.Recent studies have demonstrated the multifaceted aspects of eNTP metabolism and their signal transduction in MSCs and revealed important roles in specifying differentiation lineages and modulating MSC physiology and communication with other cells.This review discusses the roles of eNTPs,their receptors and ectoenzymes,and the relevance of the signaling network and MSC functions,and also focuses on the importance of this emerging area of interest for future MSC-based cell therapies.展开更多
Microbial ectoenzymes play essential roles in the transformation and mineralization of organic matter in the ocean.However,conventional methods for measuring microbial ectoenzyme activities(MEAs)in the deep ocean unde...Microbial ectoenzymes play essential roles in the transformation and mineralization of organic matter in the ocean.However,conventional methods for measuring microbial ectoenzyme activities(MEAs)in the deep ocean under atmospheric conditions can misrepresent the metabolic activities of indigenous microbial communities.To overcome this limitation,we measured the activities of three microbial ectoenzymes(aminopeptidase,α-glucosidase,andβ-glucosidase)under both atmospheric and in situ pressure conditions in seawater collected using pressure-retaining and non-pressure-retaining samplers in the Challenger Deep,Mariana Trench.In the case of aminopeptidase andα-glucosidase,the highest isobaric MEAs were observed in the surface layer(50 m),followed by those at abyssopelagic depths(4,000–6,000 m)for aminopeptidase,hadal realm(10,903 m)forα-glucosidase,whileβ-glucosidase activity exhibited the highest value at 10,903 m.Furthermore,the isobaric MEAs in hadal waters were commonly found to be higher than the decompressed counterparts,highlighting the importance of pressure-retaining sampling and isobaric enzymatic assays.The half-saturation constant(K_(m))showed a general decreasing trend with depth,suggesting that the deep ocean microbes might have adapted to the high-pressure and oligotrophic environment by increasing their ectoenzyme's affinity to substrate.Furthermore,particle-free MEAs contribute more to the total MEAs in the deep ocean than particle-associated MEAs,suggesting the significance of cell-associated and dissolved ectoenzymes in ocean ecosystems.This study provides a foundation for future investigations of MEAs in the ocean and has important implications for understanding the dynamics of microbially mediated biogeochemical cycling in marine ecosystems.展开更多
基金supported by the China Ocean Mineral Resources R&D Association(No.DYXM-115-02-2-01)the National Natural Science Foundation of China(No.40830213)the Hi-Tech Research and Development Program(863) of China(No.2007AA091904)
文摘The response of bacteria to various carbohydrates in the deep-sea sediments and the Antarctic soils was investigated using cellulose, chitin, and olive oil. It was found that the carbohydrates significantly increased the corresponding specific ectoenzyme activity （β- glucosidase, β-N-acetylglucosaminidase, lipase） in the samples from deep-sea sediments. In the case of Antarctic soil samples, the cellulose or olive oil amendments had minor or no effect on β-glucosidase or lipase activity, except the chitin which stimulated β- N-acetylglucosaminidase production. The responses of the bacteria in the deep-sea sediment sample WP02-3 and the Antarctic soil sample CC-TY2 towards the chitin amendment were further analyzed. Chitin amendments were shown to stimulate the ectoenzyme activity in all the tested sediments and the soils. The bacterial response before and after the carbohydrates amendments were compared by denaturing gradient gel electrophoresis and quantitative competitive polymerase chain reaction. Significant changes were found in the structure and density of the bacterial community in the deep sea sediments as compared to the Antarctic soil sample, where the effects were relatively lower. There was no change in the bacterial population in both studied samples in response to carbohydrates amendments. These data indicate that the bacterial communities in the oligotrophic deep-sea sediments are more dynamic than that in the Antarctic soils as they respond to the nutrient sources efficiently by regulation of ectoenzyme activity and/or changing community structure.
文摘Human mesenchymal stem cells(MSCs)are a rare population of non-hematopoietic stem cells with multilineage potential,originally identified in the bone marrow.Due to the lack of a single specific marker,MSCs can be recognized and isolated by a series of features such as plastic adherence,a panel of surface markers,the clonogenic and the differentiation abilities.The recognized role of MSCs in the regulation of hemopoiesis,in cell-degeneration protection and in the homeostasis of mesodermal tissues through their differentiation properties,justifies the current interest in identifying the biochemical signals produced by MSCs and their active crosstalk in tissue environments.Only recently have extracellular nucleotides(eNTPs)and their metabolites been included among the molecular signals produced by MSCs.These molecules are active on both ionotropic and metabotropic receptors present in most cell types.MSCs possess a significant display of these receptors and of nucleotide processing ectoenzymes on their plasma membrane.Thus,from their niche,MSCs give a significant contribution to the complex signaling network of eNTPs and its derivatives.Recent studies have demonstrated the multifaceted aspects of eNTP metabolism and their signal transduction in MSCs and revealed important roles in specifying differentiation lineages and modulating MSC physiology and communication with other cells.This review discusses the roles of eNTPs,their receptors and ectoenzymes,and the relevance of the signaling network and MSC functions,and also focuses on the importance of this emerging area of interest for future MSC-based cell therapies.
基金supported by the National Natural Science Foundation of China(Grant No.92251303)the Shanghai Municipal Education Commission(Grant No.2023ZKZD53)the Marine Biomedical Science and Technology Innovation Platform。
文摘Microbial ectoenzymes play essential roles in the transformation and mineralization of organic matter in the ocean.However,conventional methods for measuring microbial ectoenzyme activities(MEAs)in the deep ocean under atmospheric conditions can misrepresent the metabolic activities of indigenous microbial communities.To overcome this limitation,we measured the activities of three microbial ectoenzymes(aminopeptidase,α-glucosidase,andβ-glucosidase)under both atmospheric and in situ pressure conditions in seawater collected using pressure-retaining and non-pressure-retaining samplers in the Challenger Deep,Mariana Trench.In the case of aminopeptidase andα-glucosidase,the highest isobaric MEAs were observed in the surface layer(50 m),followed by those at abyssopelagic depths(4,000–6,000 m)for aminopeptidase,hadal realm(10,903 m)forα-glucosidase,whileβ-glucosidase activity exhibited the highest value at 10,903 m.Furthermore,the isobaric MEAs in hadal waters were commonly found to be higher than the decompressed counterparts,highlighting the importance of pressure-retaining sampling and isobaric enzymatic assays.The half-saturation constant(K_(m))showed a general decreasing trend with depth,suggesting that the deep ocean microbes might have adapted to the high-pressure and oligotrophic environment by increasing their ectoenzyme's affinity to substrate.Furthermore,particle-free MEAs contribute more to the total MEAs in the deep ocean than particle-associated MEAs,suggesting the significance of cell-associated and dissolved ectoenzymes in ocean ecosystems.This study provides a foundation for future investigations of MEAs in the ocean and has important implications for understanding the dynamics of microbially mediated biogeochemical cycling in marine ecosystems.
