Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one ...Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one of the secretion systems and it usually consists of 12 genes： VirB1, VirB2 ...VirB11, and VirD4[2]. The structure and molecular mechanisms of these genes have been well analyzed in Gram-negative strains[3] and Gram-positive strains were once believed to be lack of T4SS. However, some recent studies revealed that one or more virB/D genes also exist in some kinds of Gram-positive bacteria and play similar role, and form a T4SS-like system[3]. The VirBl-like, VirB4, VirB6, and VirD4 genes were identified in the chromosome of Gram-positive bacterium Streptococcus suis in our previous studies and their role as important mobile elements for horizontal transfer to recipients in an 89 K pathogenicity island （PAl） was demonstrated[45]. However, their structure and molecular mechanisms in other strains, especially in Gram-positive strains, are remained unclear.展开更多
Leukocytes from peripheral blood (PB) are of great value for diagnosis as well as basic and clinical research. However, no easy, centrifugation-free method is available for the isolation of live leukocytes from blood....Leukocytes from peripheral blood (PB) are of great value for diagnosis as well as basic and clinical research. However, no easy, centrifugation-free method is available for the isolation of live leukocytes from blood. We here develop a simple and quick method for the purification of viable leukocytes from whole blood using novel tools, named tLeukoCatch (tip-type) or sLeukoCatch (syringe-type), which is equipped with three Pall filter layers and captures leukocytes but not red blood cells (RBCs) in whole blood. Indeed, we showed that several million leukocytes per mL (~35% of the recovery rate) were captured and eluted from whole blood. The number of contaminant RBCs decreased from several million to several thousand. When mouse blood was hemolysed, almost all of the lysed RBC fragments were removed by passage through sLeukoCatch. Optical microscopic observation confirmed that the recovered leukocytes were sufficiently healthy to respond to growth stimuli. Efficient leukocyte recovery was also confirmed for hemolysed human blood. These results suggest that the LeukoCatchTM system is useful for bedside diagnosis and basic research with blood samples.展开更多
The development of a cost-competitive bioprocess requires that the cell factory converts the feedstock into the product of interest at high rates and yields.However,microbial cell factories are exposed to a variety of...The development of a cost-competitive bioprocess requires that the cell factory converts the feedstock into the product of interest at high rates and yields.However,microbial cell factories are exposed to a variety of different stresses during the fermentation process.These stresses can be derived from feedstocks,metabolism,or industrial production processes,limiting production capacity and diminishing competitiveness.Improving stress tolerance and robustness allows for more efficient production and ultimately makes a process more economically viable.This review summarises general trends and updates the most recent developments in technologies to improve the stress tolerance of microorganisms.We first look at evolutionary,systems biology and computational methods as examples of non-rational approaches.Then we review the(semi-)rational approaches of membrane and tran-scription factor engineering for improving tolerance phenotypes.We further discuss challenges and perspectives associated with these different approaches.展开更多
基金supported by the National Natural Science Foundation of China (No. 81201322)the Priority Project on Infectious Disease Control and Prevention 2011ZX10004-001 and 2013ZX10003006-002 by the Chinese Ministry of Science and Technology and the Chinese Ministry of Healththe Foundation of State Key Laboratory for Infectious Disease Prevention and Control (Grand No. 2011SKLID303)
文摘Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one of the secretion systems and it usually consists of 12 genes： VirB1, VirB2 ...VirB11, and VirD4[2]. The structure and molecular mechanisms of these genes have been well analyzed in Gram-negative strains[3] and Gram-positive strains were once believed to be lack of T4SS. However, some recent studies revealed that one or more virB/D genes also exist in some kinds of Gram-positive bacteria and play similar role, and form a T4SS-like system[3]. The VirBl-like, VirB4, VirB6, and VirD4 genes were identified in the chromosome of Gram-positive bacterium Streptococcus suis in our previous studies and their role as important mobile elements for horizontal transfer to recipients in an 89 K pathogenicity island （PAl） was demonstrated[45]. However, their structure and molecular mechanisms in other strains, especially in Gram-positive strains, are remained unclear.
文摘Leukocytes from peripheral blood (PB) are of great value for diagnosis as well as basic and clinical research. However, no easy, centrifugation-free method is available for the isolation of live leukocytes from blood. We here develop a simple and quick method for the purification of viable leukocytes from whole blood using novel tools, named tLeukoCatch (tip-type) or sLeukoCatch (syringe-type), which is equipped with three Pall filter layers and captures leukocytes but not red blood cells (RBCs) in whole blood. Indeed, we showed that several million leukocytes per mL (~35% of the recovery rate) were captured and eluted from whole blood. The number of contaminant RBCs decreased from several million to several thousand. When mouse blood was hemolysed, almost all of the lysed RBC fragments were removed by passage through sLeukoCatch. Optical microscopic observation confirmed that the recovered leukocytes were sufficiently healthy to respond to growth stimuli. Efficient leukocyte recovery was also confirmed for hemolysed human blood. These results suggest that the LeukoCatchTM system is useful for bedside diagnosis and basic research with blood samples.
基金the Novo Nordisk Foundation(NNF18OC0034844)the Chalmers Foundation and Angpanneforeningens Forskningsstiftelse.
文摘The development of a cost-competitive bioprocess requires that the cell factory converts the feedstock into the product of interest at high rates and yields.However,microbial cell factories are exposed to a variety of different stresses during the fermentation process.These stresses can be derived from feedstocks,metabolism,or industrial production processes,limiting production capacity and diminishing competitiveness.Improving stress tolerance and robustness allows for more efficient production and ultimately makes a process more economically viable.This review summarises general trends and updates the most recent developments in technologies to improve the stress tolerance of microorganisms.We first look at evolutionary,systems biology and computational methods as examples of non-rational approaches.Then we review the(semi-)rational approaches of membrane and tran-scription factor engineering for improving tolerance phenotypes.We further discuss challenges and perspectives associated with these different approaches.
