The insecticidal protein produced by Pseudomonas pseudoalcaligenes is purified from the suspension of the bacterial culture. As an intact molecule, the protein acts on the foregut, midgut, hindgut, vasa Malpighii and ...The insecticidal protein produced by Pseudomonas pseudoalcaligenes is purified from the suspension of the bacterial culture. As an intact molecule, the protein acts on the foregut, midgut, hindgut, vasa Malpighii and fat body, and kills locusts. The disinsection rates of feeding and injection are 63.3% and 65.7%, respectively. After 24h to 48h, it is observed that all these tissues and cells show pathological changes in varying degrees, and so did the host cellular organs of these cells, such as cytoblast, mitochondria, endoplasmic reticulum and ribosome. Particularly, the changes of the mitochondria are much more serious than those of others. Detection of oxygen electrode shows the efficiency of oxidative phosphorylation and the ATP synthesis decreases, while the activity of mitochondrial ATPase is almost not affected. That means the energy utilization of locusts is in gear, but the shortage of the supplying of energy results in their death. This research forms the substantial basis for controlling locusts.展开更多
We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures（24, 28 and 32℃）. G...We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures（24, 28 and 32℃）. Gas chromatography-mass spectrometry was applied to measure off-flavor compounds dimethyl sulfide（DMS）, dimethyl trisulfide（DMTS）,2-methylisoborneol, geosmin（GEO） and β-cyclocitral. During the lag phase of co-cultured M. aeruginosa（first 15 days）, P. pseudoalcaligenes significantly increased the production of DMS, DMTS and β-cyclocitral at all three temperatures. In the exponential phase of co-cultured M. aeruginosa（after 15 days）, M. aeruginosa became the main factor on off-flavors in the co-culture system, and β-cyclocitral turned to the highest off-flavor compound. These results also indicated that DMS, DMTS and β-cyclocitral were the main off-flavor compounds in our M. aeruginosa/P. pseudoalcaligenes co-culture system. Univariate analysis was applied to investigate the effects of M. aeruginosa and P. pseudoalcaligenes on the production of off-flavors. The results demonstrated that both M. aeruginosa and P. pseudoalcaligenes could increase the production of DMS and DMTS, while β-cyclocitral was mainly determined by M. aeruginosa. Our results also provide some insights into understanding the relationship between cyanobacteria and heterotrophic bacteria.展开更多
Pseudomonas pseudoalcaligenes strain M1\|2 isolated from oil\|contaminated soil collected from an oilfield in northern China was found to be able to synthesize a blend of polyhydroxyalkanoates (PHAs) containing mono...Pseudomonas pseudoalcaligenes strain M1\|2 isolated from oil\|contaminated soil collected from an oilfield in northern China was found to be able to synthesize a blend of polyhydroxyalkanoates (PHAs) containing monomers of 3\|hydroxybutyrate (C4), 3\|hydroxyvalerate (C5), 3\|hydroxyheptanoate (C7), 3\|hydroxyoctanoate (C8), 3\|hydroxynonanoate (C9), 3\|hydroxydecanoate (C10) and 3\|hydroxydodecanoate (C12) from various carbon sources. The hydroxyalkanoate (HA) monomer composition varied both quantitatively and qualitatively, depending on the carbon sources used. The presence of octanoate in substrates of myristic acid or tridecanoate promoted the synthesis of HB monomer in the blend. Concentration of octanoate was also found to significantly affect the PHB content in the blend. A PHA biosynthesis pathway in Pseudomonas pseudoalcaligens M1\|2 was proposed.展开更多
The isolation of microorganisms for biodegradation of minimal fats and oils at low temperatures was reported. By using rapeseed oil as a sole carbon source, six strains were isolated from five kinds of oils/fats-conta...The isolation of microorganisms for biodegradation of minimal fats and oils at low temperatures was reported. By using rapeseed oil as a sole carbon source, six strains were isolated from five kinds of oils/fats-contaminated wastewater, soil, and active sludge. Among them, two strains which show the highest oil removal ratios were identified as Pseudomonas pseudoalcaligenes and Pseudomonas mendocina, respectively. The experiments of orthogonal impact conditions show that the optimal oil degradation condition is at pH 8.0, 5 ℃ and 100 mg/L oil. Under this condition, the rapeseed oil degradation ratios of two strains after 24 hours amount to 92.6% and 92.0% respectively, whereas the removal ratios of lard decrease to 39.5% and 54.3%.展开更多
Promoter-probe vector pSUPV4 is used to clone the promoter of Pseudomonas pseudoalcaligenes directly in E. coli, and the recombinant pPA7, which has the highest kanamycin resistance, is obtained. Sequencing the PA7 fr...Promoter-probe vector pSUPV4 is used to clone the promoter of Pseudomonas pseudoalcaligenes directly in E. coli, and the recombinant pPA7, which has the highest kanamycin resistance, is obtained. Sequencing the PA7 fragment discloses several motifs similar to the conservative domains of prokaryotic promoters, including -10 box, -35 box, parallel SD fragment essential to transcription initiation, and the translation initiation site ATG. Southern blotting of PA7 indicates that the PA7 fragment comes from P. pseudoalcaligenes genome and has probably one copy. The PA7 fragment is subcloned by PCR, and the result shows that the 5’-flanking fragment from 889 to 1120 bp has promoter activity, which can be enhanced by the 0.7Kb fragment at 5’ end. The fragments of pPA7 and pPA7-2 are transferred into pseudomonas pseudoaligenes by electroporation, and the significant higher kanamycin resistance of transformants than that of control indicates that the PA7 fragment has the promoter activity in P. pseudoaligene.展开更多
文摘The insecticidal protein produced by Pseudomonas pseudoalcaligenes is purified from the suspension of the bacterial culture. As an intact molecule, the protein acts on the foregut, midgut, hindgut, vasa Malpighii and fat body, and kills locusts. The disinsection rates of feeding and injection are 63.3% and 65.7%, respectively. After 24h to 48h, it is observed that all these tissues and cells show pathological changes in varying degrees, and so did the host cellular organs of these cells, such as cytoblast, mitochondria, endoplasmic reticulum and ribosome. Particularly, the changes of the mitochondria are much more serious than those of others. Detection of oxygen electrode shows the efficiency of oxidative phosphorylation and the ATP synthesis decreases, while the activity of mitochondrial ATPase is almost not affected. That means the energy utilization of locusts is in gear, but the shortage of the supplying of energy results in their death. This research forms the substantial basis for controlling locusts.
基金supported by the National Basic Research Program (973) of China (No. 2008CB418101)the State Key Laboratory of Freshwater Ecology and Biotechnology (No. 2008FBZ01)
文摘We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures（24, 28 and 32℃）. Gas chromatography-mass spectrometry was applied to measure off-flavor compounds dimethyl sulfide（DMS）, dimethyl trisulfide（DMTS）,2-methylisoborneol, geosmin（GEO） and β-cyclocitral. During the lag phase of co-cultured M. aeruginosa（first 15 days）, P. pseudoalcaligenes significantly increased the production of DMS, DMTS and β-cyclocitral at all three temperatures. In the exponential phase of co-cultured M. aeruginosa（after 15 days）, M. aeruginosa became the main factor on off-flavors in the co-culture system, and β-cyclocitral turned to the highest off-flavor compound. These results also indicated that DMS, DMTS and β-cyclocitral were the main off-flavor compounds in our M. aeruginosa/P. pseudoalcaligenes co-culture system. Univariate analysis was applied to investigate the effects of M. aeruginosa and P. pseudoalcaligenes on the production of off-flavors. The results demonstrated that both M. aeruginosa and P. pseudoalcaligenes could increase the production of DMS and DMTS, while β-cyclocitral was mainly determined by M. aeruginosa. Our results also provide some insights into understanding the relationship between cyanobacteria and heterotrophic bacteria.
基金the Trans-Century Training Pro gramme Foundation for Talent by the Ministry of Education of China and the Major Research
文摘Pseudomonas pseudoalcaligenes strain M1\|2 isolated from oil\|contaminated soil collected from an oilfield in northern China was found to be able to synthesize a blend of polyhydroxyalkanoates (PHAs) containing monomers of 3\|hydroxybutyrate (C4), 3\|hydroxyvalerate (C5), 3\|hydroxyheptanoate (C7), 3\|hydroxyoctanoate (C8), 3\|hydroxynonanoate (C9), 3\|hydroxydecanoate (C10) and 3\|hydroxydodecanoate (C12) from various carbon sources. The hydroxyalkanoate (HA) monomer composition varied both quantitatively and qualitatively, depending on the carbon sources used. The presence of octanoate in substrates of myristic acid or tridecanoate promoted the synthesis of HB monomer in the blend. Concentration of octanoate was also found to significantly affect the PHB content in the blend. A PHA biosynthesis pathway in Pseudomonas pseudoalcaligens M1\|2 was proposed.
文摘The isolation of microorganisms for biodegradation of minimal fats and oils at low temperatures was reported. By using rapeseed oil as a sole carbon source, six strains were isolated from five kinds of oils/fats-contaminated wastewater, soil, and active sludge. Among them, two strains which show the highest oil removal ratios were identified as Pseudomonas pseudoalcaligenes and Pseudomonas mendocina, respectively. The experiments of orthogonal impact conditions show that the optimal oil degradation condition is at pH 8.0, 5 ℃ and 100 mg/L oil. Under this condition, the rapeseed oil degradation ratios of two strains after 24 hours amount to 92.6% and 92.0% respectively, whereas the removal ratios of lard decrease to 39.5% and 54.3%.
文摘Promoter-probe vector pSUPV4 is used to clone the promoter of Pseudomonas pseudoalcaligenes directly in E. coli, and the recombinant pPA7, which has the highest kanamycin resistance, is obtained. Sequencing the PA7 fragment discloses several motifs similar to the conservative domains of prokaryotic promoters, including -10 box, -35 box, parallel SD fragment essential to transcription initiation, and the translation initiation site ATG. Southern blotting of PA7 indicates that the PA7 fragment comes from P. pseudoalcaligenes genome and has probably one copy. The PA7 fragment is subcloned by PCR, and the result shows that the 5’-flanking fragment from 889 to 1120 bp has promoter activity, which can be enhanced by the 0.7Kb fragment at 5’ end. The fragments of pPA7 and pPA7-2 are transferred into pseudomonas pseudoaligenes by electroporation, and the significant higher kanamycin resistance of transformants than that of control indicates that the PA7 fragment has the promoter activity in P. pseudoaligene.
