[Objective] The aim was to isolate a prodigiosin producing strain and study its pigment fractions.[Method] Red pigment-producing bacteria was identified by physiological and biochemical characteristics after isolation...[Objective] The aim was to isolate a prodigiosin producing strain and study its pigment fractions.[Method] Red pigment-producing bacteria was identified by physiological and biochemical characteristics after isolation in plate.By using column chromatography and thin-layer chromatography,pigment fractions were separated and purified from the extractives of the strain after fermentation in flask,and then pigment fractions were analyzed via UV-Vis and LC/MS.[Result] A red pigment-producing Serratia marcescens strain NS-17 sampled from soil of Nanchang was isolated and identified.2 pigment fractions showing similar UV-Vis and LC/MS characters were separated and purified,the characters of fraction 1 were identical to those of prodigiosin,while fraction 2 showed a special UV-Vis absorption spectrum that had not been reported.[Conclusion] A prodigiosin-producing Serratia marcescens strain NS-17 and its 2 pigment fractions were isolated.展开更多
Threshold trait analysis was used to estimate realized heritability (h 2) of re sistance to five acaricides (three single acaricide and two mixtures) and resistance risk in Tetranychus cinnabarinus (Boiduval). Tetran...Threshold trait analysis was used to estimate realized heritability (h 2) of re sistance to five acaricides (three single acaricide and two mixtures) and resistance risk in Tetranychus cinnabarinus (Boiduval). Tetranychus cinnabarinus collected from the field of Beibei, Chongqing reared more than 60 generations under pesticide free conditions and considered s usceptible. Successively selected for about 30 generations, the strain had a 65.55-, 5.82 - , 1.23-, 5.20- and 1.42-fold increase in resistance to fenpropathrin, abam ectin, pyridaben, pyridab en-abamectin (pyridaben: abamectin=7.4:0.1, m/m) and fenpropathrin-abamectin (fenpropathri n: abamectin=8.9:0.1, m/m), respectively. The realized heritability of resista nce t o fenpropathrin, abamectin, pyridaben, pyridaben-abamectin (pyridaben: abamectin=7.4:0.1, m/m) and fenpropathrin-abamectin (fenpropathrin: abamectin=8.9:0.1, m/m) is 0.2167, 0 .0967, 0.0130, 0.0800 and 0.0172, respectively. Under the selected condition, a 10-fold incr ease in resistance would be expected 15 generations for fenpropathrin, 34 generations for abamectin , 333 generations for pyridaben, 42 generations for pyridaben-abamectin (pyridaben: a bamectin=7.4:0.1, m/m) and 200 generations for fenpropathrin-abametcin (fenpropathrin: abamectin= 8.9:0.1, m/m). The highest resistance risk of the five acaricides in Tetranychus cinnabarinus was fenpropathrin, then abamection, pyridaben-abamectin (pyridaben: abamectin=7.4:0.1, m/m), fen propathrin- abamectin (fenpropathrin: abamectin=8.9:0.1, m/m) and that to py ridaben was the lowest. The mixture of pyridaben and abamectin is not useful in delaying development of resistance in the pest to the two single acaricide while the mixture of fenpropathrin and abamectin could do it.展开更多
Bacterial prodigiosins are red-colored secondary metabolites with multiple activities,such as anticancer,antimalarial and immunosuppressive,which hold great potential for medical applications.In this study,dramaticall...Bacterial prodigiosins are red-colored secondary metabolites with multiple activities,such as anticancer,antimalarial and immunosuppressive,which hold great potential for medical applications.In this study,dramatically enhanced prodigiosins(RED) production in Streptomyces coelicolor was achieved by combinatorial metabolic engineering,including inactivation of the repressor gene ohkA,deletion of the actinorhodin(ACT) and calcium-dependent antibiotic(CDA) biosynthetic gene clusters(BGCs) and multi-copy chromosomal integration of the RED BGC.The results showed that ohkA deletion led to a 1-fold increase of RED production over the wild-type strain M145.Then,the ACT and CDA BGCs were deleted successively based on the AohkA mutant(SBJ101).To achieve multi-copy RED BGC integration,artificial ΦC31 attB site(s) were inserted simultaneously at the position where the ACT and CDA BGCs were deleted.The resulting strains SBJ102(with a single deletion of the ACT BGC and insertion of one artificial attB site) and SBJ103(with the deletion of both BGCs and insertion of two artificial attB sites) produced 1.9-and 6-fold higher RED titers than M145,respectively.Finally,the entire RED BGC was introduced into mutants from SBJ101 to SBJ103,generating three mutants(from SBJ104 to SBJ106) with chromosomal integration of one to three copies of the RED BGC.The highest RED yield was from SBJ106,which produced a maximum level of 96.8 mg g^(-1) cell dry weight,showing a 12-fold increase relative to M145.Collectively,the metabolic engineering strategies employed in this study are very efficient for the construction of high prodigiosin-producing strains.展开更多
文摘[Objective] The aim was to isolate a prodigiosin producing strain and study its pigment fractions.[Method] Red pigment-producing bacteria was identified by physiological and biochemical characteristics after isolation in plate.By using column chromatography and thin-layer chromatography,pigment fractions were separated and purified from the extractives of the strain after fermentation in flask,and then pigment fractions were analyzed via UV-Vis and LC/MS.[Result] A red pigment-producing Serratia marcescens strain NS-17 sampled from soil of Nanchang was isolated and identified.2 pigment fractions showing similar UV-Vis and LC/MS characters were separated and purified,the characters of fraction 1 were identical to those of prodigiosin,while fraction 2 showed a special UV-Vis absorption spectrum that had not been reported.[Conclusion] A prodigiosin-producing Serratia marcescens strain NS-17 and its 2 pigment fractions were isolated.
文摘Threshold trait analysis was used to estimate realized heritability (h 2) of re sistance to five acaricides (three single acaricide and two mixtures) and resistance risk in Tetranychus cinnabarinus (Boiduval). Tetranychus cinnabarinus collected from the field of Beibei, Chongqing reared more than 60 generations under pesticide free conditions and considered s usceptible. Successively selected for about 30 generations, the strain had a 65.55-, 5.82 - , 1.23-, 5.20- and 1.42-fold increase in resistance to fenpropathrin, abam ectin, pyridaben, pyridab en-abamectin (pyridaben: abamectin=7.4:0.1, m/m) and fenpropathrin-abamectin (fenpropathri n: abamectin=8.9:0.1, m/m), respectively. The realized heritability of resista nce t o fenpropathrin, abamectin, pyridaben, pyridaben-abamectin (pyridaben: abamectin=7.4:0.1, m/m) and fenpropathrin-abamectin (fenpropathrin: abamectin=8.9:0.1, m/m) is 0.2167, 0 .0967, 0.0130, 0.0800 and 0.0172, respectively. Under the selected condition, a 10-fold incr ease in resistance would be expected 15 generations for fenpropathrin, 34 generations for abamectin , 333 generations for pyridaben, 42 generations for pyridaben-abamectin (pyridaben: a bamectin=7.4:0.1, m/m) and 200 generations for fenpropathrin-abametcin (fenpropathrin: abamectin= 8.9:0.1, m/m). The highest resistance risk of the five acaricides in Tetranychus cinnabarinus was fenpropathrin, then abamection, pyridaben-abamectin (pyridaben: abamectin=7.4:0.1, m/m), fen propathrin- abamectin (fenpropathrin: abamectin=8.9:0.1, m/m) and that to py ridaben was the lowest. The mixture of pyridaben and abamectin is not useful in delaying development of resistance in the pest to the two single acaricide while the mixture of fenpropathrin and abamectin could do it.
基金supported by the National Natural Science Foundation of China(31430004,31421061,31630003,31370081 and 31570072)the Science and Technology Commission of Shanghai Municipality(16490712100)
文摘Bacterial prodigiosins are red-colored secondary metabolites with multiple activities,such as anticancer,antimalarial and immunosuppressive,which hold great potential for medical applications.In this study,dramatically enhanced prodigiosins(RED) production in Streptomyces coelicolor was achieved by combinatorial metabolic engineering,including inactivation of the repressor gene ohkA,deletion of the actinorhodin(ACT) and calcium-dependent antibiotic(CDA) biosynthetic gene clusters(BGCs) and multi-copy chromosomal integration of the RED BGC.The results showed that ohkA deletion led to a 1-fold increase of RED production over the wild-type strain M145.Then,the ACT and CDA BGCs were deleted successively based on the AohkA mutant(SBJ101).To achieve multi-copy RED BGC integration,artificial ΦC31 attB site(s) were inserted simultaneously at the position where the ACT and CDA BGCs were deleted.The resulting strains SBJ102(with a single deletion of the ACT BGC and insertion of one artificial attB site) and SBJ103(with the deletion of both BGCs and insertion of two artificial attB sites) produced 1.9-and 6-fold higher RED titers than M145,respectively.Finally,the entire RED BGC was introduced into mutants from SBJ101 to SBJ103,generating three mutants(from SBJ104 to SBJ106) with chromosomal integration of one to three copies of the RED BGC.The highest RED yield was from SBJ106,which produced a maximum level of 96.8 mg g^(-1) cell dry weight,showing a 12-fold increase relative to M145.Collectively,the metabolic engineering strategies employed in this study are very efficient for the construction of high prodigiosin-producing strains.
