The inhibitory effect of gadolinium on Sinorhizobium fredii USDA 205 was studied on a global scale using twodimensional gel electrophoresis and MALDI-TOF MS. The results indicated that 22 proteins were significantly a...The inhibitory effect of gadolinium on Sinorhizobium fredii USDA 205 was studied on a global scale using twodimensional gel electrophoresis and MALDI-TOF MS. The results indicated that 22 proteins were significantly affected by 1 mmol · L^-1 Gd^3 ＋ treatment when compared with an untreated control. Among these proteins, nine were up-regulated and thirteen were down-regulated. The differently expressed proteins were classified into 8 functional categories based on their functions, including transporters, proteins for cellular defence, and proteins involved in metabolism.展开更多
Previous investigations have shown that nifA gene is involved in nodulation and symbiotic nitrogen fixation regulation of Rhizobium. We study the role of nifA on nodulation of leguminous plants. We found that Sinorhiz...Previous investigations have shown that nifA gene is involved in nodulation and symbiotic nitrogen fixation regulation of Rhizobium. We study the role of nifA on nodulation of leguminous plants. We found that Sinorhizo-bium fredii harboring multi-copy plasmid carrying the con-stitutively expressed Klebsiella pneumoniae nifA exhibited an increase of nodulation activity and nodulation competitiveness on soybean plants. The Nod-factor secreted by the rhizobia cells containing the multi-copied nifA was assayed, and preliminary results showed that S. fredii containing the multi-copy plasmid carrying nifA produced higher strength of Nod-factor than the rhizobia containing the same plasmid carrying the vector did.展开更多
Sinorhizobium fredii strain HN01 can use proline as the sole carbon and nitrogen source. A mutant strain GXHN100 unable to catabolize proline was screened from 6000 Tn5gusA5 random insertional mutants of S.fredii stra...Sinorhizobium fredii strain HN01 can use proline as the sole carbon and nitrogen source. A mutant strain GXHN100 unable to catabolize proline was screened from 6000 Tn5gusA5 random insertional mutants of S.fredii strain HN01. Sequencing analysis showed that an open read- ing frame, named pmrA (proline metabolic relative), was inserted by the Tn5gusA5. A positive clone, named pGXHN100 which containing 3.3kb foreign DNA fragment of S.fredii strain HN01, was isolated from a partial gene library of S.fredii HN01 by colony in situ hybridization. Sequence analysis showed that pGXHN100 contained the entire pmrA gene. The 3.3kb DNA fragment of pGXHN100 was cloned into a broad-host-range cosmid vector pLAFR3 to form plasmid pGXHN200 which was subsequently introduced into GXHN100 to form a complemented strain GXHN200. Plant test showed that GXHN100 was effective and no obvious changes in nitrogenase activity comparing with parental strain. But GXHN100 nodulated 2 days later on soybean and its nodulation efficiency and competitiveness were decreased. The complemented strain GXHN200 restored the nodulation efficiency and competitiveness of GXHN100 to the wild type.展开更多
Sinorhizobium fredii RT19, a strain of free- living bacteria, was subjected to salt shock and its protein expression profiles were analyzed by differential display proteome approaches. The results of separation by two...Sinorhizobium fredii RT19, a strain of free- living bacteria, was subjected to salt shock and its protein expression profiles were analyzed by differential display proteome approaches. The results of separation by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) showed that the number of resolved proteins was 481, 465 and 424, corresponding to salt-free control, 5 and 50 min 1 mol/L salt treatment, respectively. Among the resolved proteins, 82 in total had altered expression in response to salt-shock stress. 26 out of the 82 proteins were induced and 23 were completely inhibited, while 12 were up-regulated and 21 down-regulated in response to salt shock. In addition, the appearance of differentially displayed proteins responding to different salt shock periods is also reported. The identity of the 26 induced proteins was revealed by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) followed by database searching. Among them, 20 were assigned to proteins with known functions. Their roles in response to salt shock stress are discussed.展开更多
基金Project supported by the National Natural Science Foundation of China (G2001CB108902 ,2004CB418506)
文摘The inhibitory effect of gadolinium on Sinorhizobium fredii USDA 205 was studied on a global scale using twodimensional gel electrophoresis and MALDI-TOF MS. The results indicated that 22 proteins were significantly affected by 1 mmol · L^-1 Gd^3 ＋ treatment when compared with an untreated control. Among these proteins, nine were up-regulated and thirteen were down-regulated. The differently expressed proteins were classified into 8 functional categories based on their functions, including transporters, proteins for cellular defence, and proteins involved in metabolism.
基金ACKN0WLEDGEMENT This work is part of the joint EC-prokect no. TS3-CT92-0127 and was supported in part by the National Natural Science Foundation of China （NSFC）.
基金This work was supported by the State "863" High-Tech Programs and the fund of the Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences.
文摘Previous investigations have shown that nifA gene is involved in nodulation and symbiotic nitrogen fixation regulation of Rhizobium. We study the role of nifA on nodulation of leguminous plants. We found that Sinorhizo-bium fredii harboring multi-copy plasmid carrying the con-stitutively expressed Klebsiella pneumoniae nifA exhibited an increase of nodulation activity and nodulation competitiveness on soybean plants. The Nod-factor secreted by the rhizobia cells containing the multi-copied nifA was assayed, and preliminary results showed that S. fredii containing the multi-copy plasmid carrying nifA produced higher strength of Nod-factor than the rhizobia containing the same plasmid carrying the vector did.
文摘Sinorhizobium fredii strain HN01 can use proline as the sole carbon and nitrogen source. A mutant strain GXHN100 unable to catabolize proline was screened from 6000 Tn5gusA5 random insertional mutants of S.fredii strain HN01. Sequencing analysis showed that an open read- ing frame, named pmrA (proline metabolic relative), was inserted by the Tn5gusA5. A positive clone, named pGXHN100 which containing 3.3kb foreign DNA fragment of S.fredii strain HN01, was isolated from a partial gene library of S.fredii HN01 by colony in situ hybridization. Sequence analysis showed that pGXHN100 contained the entire pmrA gene. The 3.3kb DNA fragment of pGXHN100 was cloned into a broad-host-range cosmid vector pLAFR3 to form plasmid pGXHN200 which was subsequently introduced into GXHN100 to form a complemented strain GXHN200. Plant test showed that GXHN100 was effective and no obvious changes in nitrogenase activity comparing with parental strain. But GXHN100 nodulated 2 days later on soybean and its nodulation efficiency and competitiveness were decreased. The complemented strain GXHN200 restored the nodulation efficiency and competitiveness of GXHN100 to the wild type.
文摘Sinorhizobium fredii RT19, a strain of free- living bacteria, was subjected to salt shock and its protein expression profiles were analyzed by differential display proteome approaches. The results of separation by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) showed that the number of resolved proteins was 481, 465 and 424, corresponding to salt-free control, 5 and 50 min 1 mol/L salt treatment, respectively. Among the resolved proteins, 82 in total had altered expression in response to salt-shock stress. 26 out of the 82 proteins were induced and 23 were completely inhibited, while 12 were up-regulated and 21 down-regulated in response to salt shock. In addition, the appearance of differentially displayed proteins responding to different salt shock periods is also reported. The identity of the 26 induced proteins was revealed by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) followed by database searching. Among them, 20 were assigned to proteins with known functions. Their roles in response to salt shock stress are discussed.
