Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession ...Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.展开更多
DnaK is implicated in protein folding, repair and degradation. Its protective role during heat shock is well documented and many other stresses can also induce its production. Using a competitive ELISA, intracellular ...DnaK is implicated in protein folding, repair and degradation. Its protective role during heat shock is well documented and many other stresses can also induce its production. Using a competitive ELISA, intracellular DnaK concentrations were determined in Escherichia coli ATCC 25922 exposed to a γ-irradiation dose of 0.3 KGy applied either at high (8 × 10-2 KGy/min) or low rates (3 × 10-3 KGy/min) and with or without a recuperation period of 22 h at 37℃ post-treatment. All four irradiation treatments reduced cell counts similarly and significantly compared to the control (P < 0.0001). However, the highest DnaK concentration was observed in cells irradiated at low rate without recuperation (105,416 molecules/cell;P = 0.0001). Furthermore, DnaK levels remained higher than the control (38,500 molecules/ cell) after the recuperation period (P < 0.05). Variation in the intracellular DnaK concentration indicates that the bacterial stress response was modulated differently according to the irradiation treatment (P = 0.0001).展开更多
基金The work was supported by the Hi-Tech Research and Development Program of China under contract Nos 2006AA09Z414 and 2007AA091903；the China Ocean Mineral Resources R ＆ D Association under contract No. DYXM - 115 - 02 - 2 - 6；the National Natural Science Foundation of China under contract No. Z2004D02；the Natural Science Foundation of Shandong Province of China under contract No. Z2004D02；the Foundation for Young Excellent Scientists in Shandong Province of China under contract No. 2006BS02002；the Program for New Century Excellent Talents in University under contract No. NCET - 06 - 0578.
文摘Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.
文摘DnaK is implicated in protein folding, repair and degradation. Its protective role during heat shock is well documented and many other stresses can also induce its production. Using a competitive ELISA, intracellular DnaK concentrations were determined in Escherichia coli ATCC 25922 exposed to a γ-irradiation dose of 0.3 KGy applied either at high (8 × 10-2 KGy/min) or low rates (3 × 10-3 KGy/min) and with or without a recuperation period of 22 h at 37℃ post-treatment. All four irradiation treatments reduced cell counts similarly and significantly compared to the control (P < 0.0001). However, the highest DnaK concentration was observed in cells irradiated at low rate without recuperation (105,416 molecules/cell;P = 0.0001). Furthermore, DnaK levels remained higher than the control (38,500 molecules/ cell) after the recuperation period (P < 0.05). Variation in the intracellular DnaK concentration indicates that the bacterial stress response was modulated differently according to the irradiation treatment (P = 0.0001).
