Actinomycetes population from continental slope sediment of the Bay of Bengal was studied. Samples were collected during two voyages of FORV Sagar Sampada in 2004 (May-June) and 2005 (July) respectively from 11 tr...Actinomycetes population from continental slope sediment of the Bay of Bengal was studied. Samples were collected during two voyages of FORV Sagar Sampada in 2004 (May-June) and 2005 (July) respectively from 11 transects (each transect had ca. 200 m, 500 m, and 1 000 m depth stations). The physicochemical parameters of overlying water, and sediment samples were also recorded. The actinomycete population ranged from 5.17 to 51.94 CFU/g dry sediment weight and 9.38 to 45.22 CFU/g dry sediment weight during the two cruises respectively. No actinomycete colony was isolated from stations in 1 000 m depth. Two-way analysis of variance showed significant variation among stations (ANOVA two-way, P〈0.05), but no significance was found between the two cruises (ANOVA two-way, P〈0.05). Populations in stations in 500 m depth in both cruises were higher than that of 200 m depth stations with statistically insignificant difference (ANOVA two-way, P〉0.05). Three actinomycetes genera were identified. Streptomyces was found to be the dominating one in both the cruises, followed by Micromonospora, and Actinomyces. The spore of Streptomyces isolates showed the abundance in spiral spore chain. Spore surface was smooth. Multiple regression analysis revealed that the influencing physico-chemical factors were sediment pH, sediment temperature, TOC, porosity, salinity, and pressure. The media used in the present study was prepared with seawater. Thus, they may represent an autochthonous marine flora and deny the theory of land runoff carriage into the sea for adaptation to the salinity of the seawater and sediments.展开更多
A new degraded sesquiterpene was isolated from the marine actinomycete Streptomyces sp. 0616208. Its structure was elucidated as (1α; 4aα; 5α, 7β, 8aβ)-5, 8a-dimethyl-decahydrona- phthalene-1, 4a, 7-triol on th...A new degraded sesquiterpene was isolated from the marine actinomycete Streptomyces sp. 0616208. Its structure was elucidated as (1α; 4aα; 5α, 7β, 8aβ)-5, 8a-dimethyl-decahydrona- phthalene-1, 4a, 7-triol on the basis of spectroscopic data.展开更多
Thirty-six strains of marine actinomycetes were isolated from a sample of marine sediment collected from the Yellow Sea and evaluated in terms of their inhibitory activity on the growth of Aspergillus parasiticus and ...Thirty-six strains of marine actinomycetes were isolated from a sample of marine sediment collected from the Yellow Sea and evaluated in terms of their inhibitory activity on the growth of Aspergillus parasiticus and the production of norsolorinic acid using dual culture plate assay and agar diffusion methods.Among them,three strains showed strong antifungal activity and were subsequently identified as Streptomyces sp.by 16 S rRNA gene sequencing analysis.The supernatant from the fermentation of the MA01 strain was extracted sequentially with chloroform and ethyl acetate,and the activities of the extracts were determined by tip culture assay.The assay results show that both extracts inhibited mycelium growth and toxin production,and the inhibitory activities of the extracts increased as their concentrations increased.The results of this study suggest that marine actinomycetes are biologically important for the control of mycotoxins,and that these bacteria could be used as novel biopesticides against mycotoxins.展开更多
Optimal conditions for protoplasts formation of marine Actinomycete sp. isolate M048 were described, dense and disperse mycelia were cultured in SGGP medium, 0.5% glycine, lysozyme exposure (2 mg/cm^3, 37 ℃, 40 min...Optimal conditions for protoplasts formation of marine Actinomycete sp. isolate M048 were described, dense and disperse mycelia were cultured in SGGP medium, 0.5% glycine, lysozyme exposure (2 mg/cm^3, 37 ℃, 40 min), and the concentration of sucrose in protoplast buffer was 0.4 mol/dm^3 for keeping the balance of osmotic pressure. Using PEG-mediated pmtoplasts transformarion, the transformation frequency was 89 transformants per microgramme of pIJ702. Meanwhile, an effective transformation procedure was established based on intergeneric conjugation from E. coli ET12567 (pUZS002) using shuttle vectors pPM801, pPM803 and a φC31-derived integration vector pIJ8600 containing onT and attP fragments. Transformation frequencies were 5.30 ×10^-4 ±0.26 ×10^-4 , 8.92 ×10^-4 ±0. 19 ×10^-4 and 6.38 ×10^-5 ±0.41×10^-5 respectively. Further, the heterologous expression of the allophycocyanin gene (apc) in the strain M048 was used to demonstrate this transformation system. SDS - PAGE and Western blot analysis confirmed the expression of recombinant APC (rAPC).展开更多
Angucyclinones are aromatic polyketides produced by type Ⅱ polyketide synthases(PKS) and are mainly found in terrestrial actinomycetes. To discover more angucyclinones from marine actinomycetes, a genomic DNA-based...Angucyclinones are aromatic polyketides produced by type Ⅱ polyketide synthases(PKS) and are mainly found in terrestrial actinomycetes. To discover more angucyclinones from marine actinomycetes, a genomic DNA-based PCR assay targeting type Ⅱ polyketide synthases was performed. Among the 167 marine actinomycetes strains screened, twelve strains were identified as the "positive" strains possessing type Ⅱ PKS-encoding genes based on the sequencing of PCR products. One of the 12 "positive" strains, Streptomyces sp. PKU-MA00218 was selected for the large-scale fermentation based on the HPLC and TLC analysis. Four angucyclinones, 6-deoxy-8-O-methylrabelomycin(1), 8-O-methylrabelomycin(2), 8-O-methyltetrangulol(3), C-ring cleavage product of angucyclinone C(4), were isolated and their structures were elucidated based on spectroscopic analyses. The isolation of angucyclinones 1–4 highlights the power of genome mining technologies based on biosynthetic knowledge in natural products discovery.展开更多
Actinomycetes in five marine sediments collected from the Arctic Ocean atdepths of 43 to 3 050 m were cultivated using a variety of media. A total of 61 actinomycetecolonies with substrate mycelia only were observed, ...Actinomycetes in five marine sediments collected from the Arctic Ocean atdepths of 43 to 3 050 m were cultivated using a variety of media. A total of 61 actinomycetecolonies with substrate mycelia only were observed, and no colonies with aerial mycelia wereobserved under aerobic conditions at 15℃. From these colonies, 28 were selected to representdifferent morphological types. Denaturing gradient gel electrophoresis (DGGE) was used to check thepurity of isolates and select representatives for subsequent sequencing. Phylogentic analyses basedon nearly full-length 16S ribosomal RNA gene (rDNA) sequences indicated that the actinomycetesisolated were accommodated within genus Rhodococcus of family Nocardiaceae, genus Dietzia of familyDietziaceae, genera Janibacter and Terrabacter of family Instrasporangiaceae and genera Kocuria andA nhrobacter of family Micrococcaceae. One of the strains (P27-24) from the deep-sea sediment atdepth of 3 050 m was found to be identical in 16S rDNA sequence(1474/1474) with theradiation-resistant Kocuria rosea ATCC 187~T isolated from air. More than half of the isolatesshowed the similarities ranging from 99.5% to 99.9% in 16S rDNA sequence to dibenzofran-degrading,butyl 2-ethylhexanoate-hydrolysising and nitrile-metabolizing actinomycetes. All the strainsisolated were psychrotolerant bacteria and grew better on the media prepared with natural seawaterthan on the media prepared with deionized water. Three of them (Dietzia sp. P27-10, Rhodococcus sp.S11-3 and Rhodococcus sp.P11-5) had an obligate growth requirement for salt, confirming that thesestrains are indigenous marine actinomycetes.展开更多
Among the 116 actinomycetes collected from marine sediments of the Yellow Sea,56 grew slowly and appeared after 2?3 weeks of incubation.Among the 56 strains,only 3 required seawater(SW) for growth,and 21 grew well in ...Among the 116 actinomycetes collected from marine sediments of the Yellow Sea,56 grew slowly and appeared after 2?3 weeks of incubation.Among the 56 strains,only 3 required seawater(SW) for growth,and 21 grew well in the medium prepared with SW rather than distilled water(DW),while the remaining 32 grew well either with SW or with DW.Six representatives with different morphological characteristics,including 1 SW-requiring strain and 5 well-growing with SW strains,were selected for phy-logenetic analysis based on 16S rRNA gene.Two strains belong to Micrococcaceae and Nocardiopsaceae respectively.The other 4 strains belong to the family of Streptomycetaceae.In the analyzed 6 strains,one was related to Nocardiopsis spp.and the other three were related to Streptomyces spp.,representing new taxa.Bioactivity testing of fermentation products from 3 SW-requiring strains and 21 well-growing with SW strains revealed that 17 strains possessed remarkable activities against gram-positive pathogen or/and tumor cells,suggesting that they were prolific resources for natural drug discovery.展开更多
Objective:To evaluate the isolation of actinomycetes strains with potential for producing antimicrobials with high methicilin resistance capability.Methods:The soil samples were collected from four different locations...Objective:To evaluate the isolation of actinomycetes strains with potential for producing antimicrobials with high methicilin resistance capability.Methods:The soil samples were collected from four different locations of Lagos lagoon.The Actinomycetes were isolated from the samples by serial dilution using spread plate method.Isolates were selected based on their cultural characteristics as well as their Gram reaction and phenotypically and molecularly characterized Streptomyces sp.Isolates were inoculated in starch casein and Kuster’s broth media and secondary metabolites were screened for antimicrobial activity against the following microorganisms:methicillin resistant Staphylococcus aureus,Staphylococcus aureus ATCC 29213,Escherichia coli ATCC 29522,Pseudomonas aeruginosa ATCC 27853,Candida albicans,Enterococcus faecalis ATCC 29212.Coagulase-negative staphylococci isolated from HIV patients were also used(Staphylococcus warneri,Staphylococcus xylosus and Staphylococcus epidermidis).The antimicrobial metabolites of the isolates were identified using gas chromatography-mass spectrometer.Results:Extracts from isolates ULS12 and ULS13 showed antimicrobial activity against methicillin resistant Staphylococcus aureus while ULK3 inhibited Candida albicans only.The gas chromatography-mass spectrometer data analysis showed the antibiotic profile of these isolates.Conclusions:The isolates ULS12 and ULS13 were found to display the highest antimicrobial activity against the test organisms and could be a potential source of new antibiotics.展开更多
BACKGROUND: Marine actinomycetes are efficient producers of new secondary metabolites that show different biological activities, including antibacterial, antifungal, anticancer, insecticidal, and enzyme inhibition ac...BACKGROUND: Marine actinomycetes are efficient producers of new secondary metabolites that show different biological activities, including antibacterial, antifungal, anticancer, insecticidal, and enzyme inhibition activities. METHODS: The morphological, physiological, and biochemical properties of the strain Streptomyees sp. VITPSA were confirmed by conventional methods. Antibacterial, anti-oxidant, anti-inflammatory, anti-diabetic, and cytotoxic activities of Streptomyces sp. VITPSA extract were determined. The media were optimized for the production of secondary metabolites. Characterization and identification of secondary metabolites were conducted by high-performance liquid chromatography, gas chromatography-mass spectroscopy, and Fourier transform infrared spectroscopy analysis. RESULTS: The strain showed significant antibacterial, anti-oxidant, and cytotoxic activities, moderate anti-inflammatory activity, and no satisfactory anti-diabetic activity. The ethyl acetate extract of Streptomyces sp. VITPSA showed maximum antibacterial activity against two gram-positive and gram-negative bacteria at 0.5 mg/mL. The antioxidant potential of the crude extract exhibited strong reducing power activity at 0.5 mg/mL with 95.1% inhibition. The cytotoxic effect was found to be an ICso of 50 gg/mL on MCF-7 cell lines. Experimental design of optimization by one-factor analysis revealed the most favorable sucrose, yeast extract, pH (7.25), and temperature (28~C) conditions for the effective production of secondary metabolites. CONCLUSION: This study revealed that Streptomyces sp. VITPSA is an excellent source of secondary metabolites with various bioactivities.展开更多
文摘Actinomycetes population from continental slope sediment of the Bay of Bengal was studied. Samples were collected during two voyages of FORV Sagar Sampada in 2004 (May-June) and 2005 (July) respectively from 11 transects (each transect had ca. 200 m, 500 m, and 1 000 m depth stations). The physicochemical parameters of overlying water, and sediment samples were also recorded. The actinomycete population ranged from 5.17 to 51.94 CFU/g dry sediment weight and 9.38 to 45.22 CFU/g dry sediment weight during the two cruises respectively. No actinomycete colony was isolated from stations in 1 000 m depth. Two-way analysis of variance showed significant variation among stations (ANOVA two-way, P〈0.05), but no significance was found between the two cruises (ANOVA two-way, P〈0.05). Populations in stations in 500 m depth in both cruises were higher than that of 200 m depth stations with statistically insignificant difference (ANOVA two-way, P〉0.05). Three actinomycetes genera were identified. Streptomyces was found to be the dominating one in both the cruises, followed by Micromonospora, and Actinomyces. The spore of Streptomyces isolates showed the abundance in spiral spore chain. Spore surface was smooth. Multiple regression analysis revealed that the influencing physico-chemical factors were sediment pH, sediment temperature, TOC, porosity, salinity, and pressure. The media used in the present study was prepared with seawater. Thus, they may represent an autochthonous marine flora and deny the theory of land runoff carriage into the sea for adaptation to the salinity of the seawater and sediments.
文摘A new degraded sesquiterpene was isolated from the marine actinomycete Streptomyces sp. 0616208. Its structure was elucidated as (1α; 4aα; 5α, 7β, 8aβ)-5, 8a-dimethyl-decahydrona- phthalene-1, 4a, 7-triol on the basis of spectroscopic data.
基金Supported by the China Ocean Mineral Resources Research and Development Association Project(No.DY125-15-R-01)the National Natural Science Foundation of China(Nos.30870003,31100090)
文摘Thirty-six strains of marine actinomycetes were isolated from a sample of marine sediment collected from the Yellow Sea and evaluated in terms of their inhibitory activity on the growth of Aspergillus parasiticus and the production of norsolorinic acid using dual culture plate assay and agar diffusion methods.Among them,three strains showed strong antifungal activity and were subsequently identified as Streptomyces sp.by 16 S rRNA gene sequencing analysis.The supernatant from the fermentation of the MA01 strain was extracted sequentially with chloroform and ethyl acetate,and the activities of the extracts were determined by tip culture assay.The assay results show that both extracts inhibited mycelium growth and toxin production,and the inhibitory activities of the extracts increased as their concentrations increased.The results of this study suggest that marine actinomycetes are biologically important for the control of mycotoxins,and that these bacteria could be used as novel biopesticides against mycotoxins.
文摘Optimal conditions for protoplasts formation of marine Actinomycete sp. isolate M048 were described, dense and disperse mycelia were cultured in SGGP medium, 0.5% glycine, lysozyme exposure (2 mg/cm^3, 37 ℃, 40 min), and the concentration of sucrose in protoplast buffer was 0.4 mol/dm^3 for keeping the balance of osmotic pressure. Using PEG-mediated pmtoplasts transformarion, the transformation frequency was 89 transformants per microgramme of pIJ702. Meanwhile, an effective transformation procedure was established based on intergeneric conjugation from E. coli ET12567 (pUZS002) using shuttle vectors pPM801, pPM803 and a φC31-derived integration vector pIJ8600 containing onT and attP fragments. Transformation frequencies were 5.30 ×10^-4 ±0.26 ×10^-4 , 8.92 ×10^-4 ±0. 19 ×10^-4 and 6.38 ×10^-5 ±0.41×10^-5 respectively. Further, the heterologous expression of the allophycocyanin gene (apc) in the strain M048 was used to demonstrate this transformation system. SDS - PAGE and Western blot analysis confirmed the expression of recombinant APC (rAPC).
基金National Natural Science Foundation of China(Grant No.81573326)
文摘Angucyclinones are aromatic polyketides produced by type Ⅱ polyketide synthases(PKS) and are mainly found in terrestrial actinomycetes. To discover more angucyclinones from marine actinomycetes, a genomic DNA-based PCR assay targeting type Ⅱ polyketide synthases was performed. Among the 167 marine actinomycetes strains screened, twelve strains were identified as the "positive" strains possessing type Ⅱ PKS-encoding genes based on the sequencing of PCR products. One of the 12 "positive" strains, Streptomyces sp. PKU-MA00218 was selected for the large-scale fermentation based on the HPLC and TLC analysis. Four angucyclinones, 6-deoxy-8-O-methylrabelomycin(1), 8-O-methylrabelomycin(2), 8-O-methyltetrangulol(3), C-ring cleavage product of angucyclinone C(4), were isolated and their structures were elucidated based on spectroscopic analyses. The isolation of angucyclinones 1–4 highlights the power of genome mining technologies based on biosynthetic knowledge in natural products discovery.
基金supported by Major Project of Chinese National Programs for Fundamental Research and Development under contract No.2004CB719601the Polar Science Innovation Fund for Young Scientists of China under contract No.JDQ200401+1 种基金the S&T Basic Work Program of China under contract No.2003DEB5J057the project“Second Chinese National Arctic Research Expedition”or CHNARE-2003 supported by the Ministry of Finance of China and organized by the Chinese Arctic and Antarctic Administration(CAA).
文摘Actinomycetes in five marine sediments collected from the Arctic Ocean atdepths of 43 to 3 050 m were cultivated using a variety of media. A total of 61 actinomycetecolonies with substrate mycelia only were observed, and no colonies with aerial mycelia wereobserved under aerobic conditions at 15℃. From these colonies, 28 were selected to representdifferent morphological types. Denaturing gradient gel electrophoresis (DGGE) was used to check thepurity of isolates and select representatives for subsequent sequencing. Phylogentic analyses basedon nearly full-length 16S ribosomal RNA gene (rDNA) sequences indicated that the actinomycetesisolated were accommodated within genus Rhodococcus of family Nocardiaceae, genus Dietzia of familyDietziaceae, genera Janibacter and Terrabacter of family Instrasporangiaceae and genera Kocuria andA nhrobacter of family Micrococcaceae. One of the strains (P27-24) from the deep-sea sediment atdepth of 3 050 m was found to be identical in 16S rDNA sequence(1474/1474) with theradiation-resistant Kocuria rosea ATCC 187~T isolated from air. More than half of the isolatesshowed the similarities ranging from 99.5% to 99.9% in 16S rDNA sequence to dibenzofran-degrading,butyl 2-ethylhexanoate-hydrolysising and nitrile-metabolizing actinomycetes. All the strainsisolated were psychrotolerant bacteria and grew better on the media prepared with natural seawaterthan on the media prepared with deionized water. Three of them (Dietzia sp. P27-10, Rhodococcus sp.S11-3 and Rhodococcus sp.P11-5) had an obligate growth requirement for salt, confirming that thesestrains are indigenous marine actinomycetes.
文摘Among the 116 actinomycetes collected from marine sediments of the Yellow Sea,56 grew slowly and appeared after 2?3 weeks of incubation.Among the 56 strains,only 3 required seawater(SW) for growth,and 21 grew well in the medium prepared with SW rather than distilled water(DW),while the remaining 32 grew well either with SW or with DW.Six representatives with different morphological characteristics,including 1 SW-requiring strain and 5 well-growing with SW strains,were selected for phy-logenetic analysis based on 16S rRNA gene.Two strains belong to Micrococcaceae and Nocardiopsaceae respectively.The other 4 strains belong to the family of Streptomycetaceae.In the analyzed 6 strains,one was related to Nocardiopsis spp.and the other three were related to Streptomyces spp.,representing new taxa.Bioactivity testing of fermentation products from 3 SW-requiring strains and 21 well-growing with SW strains revealed that 17 strains possessed remarkable activities against gram-positive pathogen or/and tumor cells,suggesting that they were prolific resources for natural drug discovery.
基金Supported by University of Lagos Central Research Committee(Grant No:2012/08).
文摘Objective:To evaluate the isolation of actinomycetes strains with potential for producing antimicrobials with high methicilin resistance capability.Methods:The soil samples were collected from four different locations of Lagos lagoon.The Actinomycetes were isolated from the samples by serial dilution using spread plate method.Isolates were selected based on their cultural characteristics as well as their Gram reaction and phenotypically and molecularly characterized Streptomyces sp.Isolates were inoculated in starch casein and Kuster’s broth media and secondary metabolites were screened for antimicrobial activity against the following microorganisms:methicillin resistant Staphylococcus aureus,Staphylococcus aureus ATCC 29213,Escherichia coli ATCC 29522,Pseudomonas aeruginosa ATCC 27853,Candida albicans,Enterococcus faecalis ATCC 29212.Coagulase-negative staphylococci isolated from HIV patients were also used(Staphylococcus warneri,Staphylococcus xylosus and Staphylococcus epidermidis).The antimicrobial metabolites of the isolates were identified using gas chromatography-mass spectrometer.Results:Extracts from isolates ULS12 and ULS13 showed antimicrobial activity against methicillin resistant Staphylococcus aureus while ULK3 inhibited Candida albicans only.The gas chromatography-mass spectrometer data analysis showed the antibiotic profile of these isolates.Conclusions:The isolates ULS12 and ULS13 were found to display the highest antimicrobial activity against the test organisms and could be a potential source of new antibiotics.
文摘BACKGROUND: Marine actinomycetes are efficient producers of new secondary metabolites that show different biological activities, including antibacterial, antifungal, anticancer, insecticidal, and enzyme inhibition activities. METHODS: The morphological, physiological, and biochemical properties of the strain Streptomyees sp. VITPSA were confirmed by conventional methods. Antibacterial, anti-oxidant, anti-inflammatory, anti-diabetic, and cytotoxic activities of Streptomyces sp. VITPSA extract were determined. The media were optimized for the production of secondary metabolites. Characterization and identification of secondary metabolites were conducted by high-performance liquid chromatography, gas chromatography-mass spectroscopy, and Fourier transform infrared spectroscopy analysis. RESULTS: The strain showed significant antibacterial, anti-oxidant, and cytotoxic activities, moderate anti-inflammatory activity, and no satisfactory anti-diabetic activity. The ethyl acetate extract of Streptomyces sp. VITPSA showed maximum antibacterial activity against two gram-positive and gram-negative bacteria at 0.5 mg/mL. The antioxidant potential of the crude extract exhibited strong reducing power activity at 0.5 mg/mL with 95.1% inhibition. The cytotoxic effect was found to be an ICso of 50 gg/mL on MCF-7 cell lines. Experimental design of optimization by one-factor analysis revealed the most favorable sucrose, yeast extract, pH (7.25), and temperature (28~C) conditions for the effective production of secondary metabolites. CONCLUSION: This study revealed that Streptomyces sp. VITPSA is an excellent source of secondary metabolites with various bioactivities.