After deregulating the purine and riboflavin synthesis in the Gram-positive bacterium Bacillus subtilis,it is critical to amplify riboflavin operon with appropriate dosage in the host strain for remarkable increase of...After deregulating the purine and riboflavin synthesis in the Gram-positive bacterium Bacillus subtilis,it is critical to amplify riboflavin operon with appropriate dosage in the host strain for remarkable increase of riboflavin production.Bacillus subtilis RH13, a riboflavin-producing strain, was selected as host strain in the construction of engineering strains by protoplast fusion. The integrative plasmid pRB63 and autonomous plasmid pRB49, pRB62 containing riboflavin operon of B.subtilis 24 were constructed and transformed into the host strain respectively. Increasing one operon copy in B.subtilis RH13 results in about 0.4 g/L improvement in riboflavin yield and the appropriate number of operon copies was about 7—8. Amplifying more riboflavin operons is of no use for further improvement of yield of riboflavin. Furthermore, excessive operon dosage results in metabolic unbalance and is fatal to the host cells producing riboflavin.展开更多
Objective To clarify the role of vitamin D receptor (VDR) expression in parathyroid proliferation and resistance of parathyroid glands to 1,25(OH) 2D 3 with secondary hyperparathyroidism (SHPT) Methods This study...Objective To clarify the role of vitamin D receptor (VDR) expression in parathyroid proliferation and resistance of parathyroid glands to 1,25(OH) 2D 3 with secondary hyperparathyroidism (SHPT) Methods This study used archive parathyroid with 7 uremic patients The expression of proliferation cell nuclear antigen (PCNA) and VDR was evaluated in nineteen surgically excised parathyroid tissues, including 11 diffuse hyperplasia (DH type) and 8 nodular hyperplasia (NH type) of parathyroid glands, by immunohistochemistry (avidin biotin complex method) Results The weight of parathyroid in SHPT was remarkably increased by 16 1 times The numbers of parathyroid cells were increased by 1 86 times The rate of PCNA was remarkably increased in parathyroid hyperplasia with SHPT compared with that in control group [(6 35±3 36)‰ vs (1 73±1 31)‰, P <0 001] The number of PCNA in DH type was lower than that in NH type ( P <0 001) The density of VDR in the parathyroid with SHPT was significantly decreased [(40 28±13 13)% vs (83 79±3 77)%, P <0 001], VDR immunoreactivity expression in NH type was lower than that in DH type [(27 14±4 12)% vs (49 84±7 33)%, P <0 001] A significantly negative correlation was found between VDR density and the weight of the parathyroid ( r =-0 46, P <0 05), the same as VDR and PCNA ( r = -0 75, P <0 001) Conclusion VDR density was significantly decreased in parathyroid tissue of uremic patients showing nodular hyperplasia compared with that in diffuse hyperplasia and there was significantly negative correlation between VDR density and the weight of the parathyroid, and this may contribute to the progression of SHPT Furthermore, VDR deficiency may cause the resistance of parathyroid cells to 1, 25(OH) 2D 3, in part展开更多
文摘After deregulating the purine and riboflavin synthesis in the Gram-positive bacterium Bacillus subtilis,it is critical to amplify riboflavin operon with appropriate dosage in the host strain for remarkable increase of riboflavin production.Bacillus subtilis RH13, a riboflavin-producing strain, was selected as host strain in the construction of engineering strains by protoplast fusion. The integrative plasmid pRB63 and autonomous plasmid pRB49, pRB62 containing riboflavin operon of B.subtilis 24 were constructed and transformed into the host strain respectively. Increasing one operon copy in B.subtilis RH13 results in about 0.4 g/L improvement in riboflavin yield and the appropriate number of operon copies was about 7—8. Amplifying more riboflavin operons is of no use for further improvement of yield of riboflavin. Furthermore, excessive operon dosage results in metabolic unbalance and is fatal to the host cells producing riboflavin.
文摘Objective To clarify the role of vitamin D receptor (VDR) expression in parathyroid proliferation and resistance of parathyroid glands to 1,25(OH) 2D 3 with secondary hyperparathyroidism (SHPT) Methods This study used archive parathyroid with 7 uremic patients The expression of proliferation cell nuclear antigen (PCNA) and VDR was evaluated in nineteen surgically excised parathyroid tissues, including 11 diffuse hyperplasia (DH type) and 8 nodular hyperplasia (NH type) of parathyroid glands, by immunohistochemistry (avidin biotin complex method) Results The weight of parathyroid in SHPT was remarkably increased by 16 1 times The numbers of parathyroid cells were increased by 1 86 times The rate of PCNA was remarkably increased in parathyroid hyperplasia with SHPT compared with that in control group [(6 35±3 36)‰ vs (1 73±1 31)‰, P <0 001] The number of PCNA in DH type was lower than that in NH type ( P <0 001) The density of VDR in the parathyroid with SHPT was significantly decreased [(40 28±13 13)% vs (83 79±3 77)%, P <0 001], VDR immunoreactivity expression in NH type was lower than that in DH type [(27 14±4 12)% vs (49 84±7 33)%, P <0 001] A significantly negative correlation was found between VDR density and the weight of the parathyroid ( r =-0 46, P <0 05), the same as VDR and PCNA ( r = -0 75, P <0 001) Conclusion VDR density was significantly decreased in parathyroid tissue of uremic patients showing nodular hyperplasia compared with that in diffuse hyperplasia and there was significantly negative correlation between VDR density and the weight of the parathyroid, and this may contribute to the progression of SHPT Furthermore, VDR deficiency may cause the resistance of parathyroid cells to 1, 25(OH) 2D 3, in part
