Rhizopines such as scyllo-inosamine (SIA) and L-3-O-methyl-scyllo-inosamine (3-O-MSI) play an int... more Rhizopines such as scyllo-inosamine (SIA) and L-3-O-methyl-scyllo-inosamine (3-O-MSI) play an intricate role as nutritional mediators during the establishment of the symbiotic relationship between legumes and rhizobia. The mechanism of action is not well understood. One challenge is the availability of rhizopines, which occur in only minute amounts in plant nodules. We herewith report an efficient synthesis of scyllo-inosamine and its biochemical activity in specific bacteria. SIA was prepared in 7 steps and 32% overall yield from readily available myo-inositol. The chemically synthesized SIA was tested to determine whether it can serve as sole carbon and nitrogen source for Sinorhizobium meliloti wild-type strain L5-30 and for strains carrying mutations in the rhizopine degradation (moc) genes. The analysis of the phenotype of the mutant strains revealed that the moc genes previously shown to be essential for the breakdown of the rhizopines isolated from root nodules are also essential for the utilization of the chemically synthesized SIA.
ABSTRACT A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designa... more ABSTRACT A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designated enterocin 62-6, was characterized following purification and DNA sequence analysis and compared to previously described bacteriocins. Enterocin 62-6 was isolated from brain heart infusion (BHI) culture supernatants using ammonium sulfate precipitation followed by elution from a Sepharose cation exchange column using a continuous salt gradient (0.1-0.7 M NaCl). SDS-PAGE of an active column fraction resulted in an electrophoretically pure protein, which corresponded to the growth inhibition of the sensitive Lactobacillus indicator strain in the gel overlay assay. Purified enterocin 62-6 was shown to be heat- and pH-stable, and sensitive to the proteolytic enzymes alpha-chymotrypsin and pepsin. Results from mass spectrometry suggested that it comprised two peptides of 5206 and 5219+/-1 Da, which was confirmed by DNA sequence analysis. The characteristics of enterocin 62-6 as a small, heat- and pH-stable, cationic, hydrophobic, two-peptide, plasmid-borne bacteriocin, with an inhibitory spectrum against a broad range of Gram-positive but not Gram-negative bacteria, were consistent with its classification as a class IIc bacteriocin. Furthermore, its wide spectrum of growth inhibitory activity against Gram-positive bacteria of vaginal origin including lactobacilli, and stability under the acidic conditions of the vagina, are consistent with our hypothesis that it could have potential significance in disrupting the ecology of the vaginal tract and pave the way for the establishment of the abnormal microbiota associated with the vaginal syndrome bacterial vaginosis. This is the first class IIc bacteriocin produced by a strain of E. faecium of vaginal origin to be characterized.
Microbial Ecology in Health and Disease, Dec 1, 2007
ABSTRACT A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designa... more ABSTRACT A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designated enterocin 62-6, was characterized following purification and DNA sequence analysis and compared to previously described bacteriocins. Enterocin 62-6 was isolated from brain heart infusion (BHI) culture supernatants using ammonium sulfate precipitation followed by elution from a Sepharose cation exchange column using a continuous salt gradient (0.1-0.7 M NaCl). SDS-PAGE of an active column fraction resulted in an electrophoretically pure protein, which corresponded to the growth inhibition of the sensitive Lactobacillus indicator strain in the gel overlay assay. Purified enterocin 62-6 was shown to be heat- and pH-stable, and sensitive to the proteolytic enzymes alpha-chymotrypsin and pepsin. Results from mass spectrometry suggested that it comprised two peptides of 5206 and 5219+/-1 Da, which was confirmed by DNA sequence analysis. The characteristics of enterocin 62-6 as a small, heat- and pH-stable, cationic, hydrophobic, two-peptide, plasmid-borne bacteriocin, with an inhibitory spectrum against a broad range of Gram-positive but not Gram-negative bacteria, were consistent with its classification as a class IIc bacteriocin. Furthermore, its wide spectrum of growth inhibitory activity against Gram-positive bacteria of vaginal origin including lactobacilli, and stability under the acidic conditions of the vagina, are consistent with our hypothesis that it could have potential significance in disrupting the ecology of the vaginal tract and pave the way for the establishment of the abnormal microbiota associated with the vaginal syndrome bacterial vaginosis. This is the first class IIc bacteriocin produced by a strain of E. faecium of vaginal origin to be characterized.
ABSTRACT Biogeophysical investigations over the last decade have provided evidence documenting th... more ABSTRACT Biogeophysical investigations over the last decade have provided evidence documenting that geophysical technique can be used to assess in-situ biogeochemical processes. In this study, we investigated a site contaminated by crude oil at Bemidji, Minnesota where intrinsic bioremediation is known to occur and iron is the dormant electron acceptor process.
Rhizopines such as scyllo-inosamine (SIA) and L-3-O-methyl-scyllo-inosamine (3-O-MSI) play an int... more Rhizopines such as scyllo-inosamine (SIA) and L-3-O-methyl-scyllo-inosamine (3-O-MSI) play an intricate role as nutritional mediators during the establishment of the symbiotic relationship between legumes and rhizobia. The mechanism of action is not well understood. One challenge is the availability of rhizopines, which occur in only minute amounts in plant nodules. We herewith report an efficient synthesis of scyllo-inosamine and its biochemical activity in specific bacteria. SIA was prepared in 7 steps and 32% overall yield from readily available myo-inositol. The chemically synthesized SIA was tested to determine whether it can serve as sole carbon and nitrogen source for Sinorhizobium meliloti wild-type strain L5-30 and for strains carrying mutations in the rhizopine degradation (moc) genes. The analysis of the phenotype of the mutant strains revealed that the moc genes previously shown to be essential for the breakdown of the rhizopines isolated from root nodules are also essential for the utilization of the chemically synthesized SIA.
ABSTRACT A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designa... more ABSTRACT A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designated enterocin 62-6, was characterized following purification and DNA sequence analysis and compared to previously described bacteriocins. Enterocin 62-6 was isolated from brain heart infusion (BHI) culture supernatants using ammonium sulfate precipitation followed by elution from a Sepharose cation exchange column using a continuous salt gradient (0.1-0.7 M NaCl). SDS-PAGE of an active column fraction resulted in an electrophoretically pure protein, which corresponded to the growth inhibition of the sensitive Lactobacillus indicator strain in the gel overlay assay. Purified enterocin 62-6 was shown to be heat- and pH-stable, and sensitive to the proteolytic enzymes alpha-chymotrypsin and pepsin. Results from mass spectrometry suggested that it comprised two peptides of 5206 and 5219+/-1 Da, which was confirmed by DNA sequence analysis. The characteristics of enterocin 62-6 as a small, heat- and pH-stable, cationic, hydrophobic, two-peptide, plasmid-borne bacteriocin, with an inhibitory spectrum against a broad range of Gram-positive but not Gram-negative bacteria, were consistent with its classification as a class IIc bacteriocin. Furthermore, its wide spectrum of growth inhibitory activity against Gram-positive bacteria of vaginal origin including lactobacilli, and stability under the acidic conditions of the vagina, are consistent with our hypothesis that it could have potential significance in disrupting the ecology of the vaginal tract and pave the way for the establishment of the abnormal microbiota associated with the vaginal syndrome bacterial vaginosis. This is the first class IIc bacteriocin produced by a strain of E. faecium of vaginal origin to be characterized.
Microbial Ecology in Health and Disease, Dec 1, 2007
ABSTRACT A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designa... more ABSTRACT A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designated enterocin 62-6, was characterized following purification and DNA sequence analysis and compared to previously described bacteriocins. Enterocin 62-6 was isolated from brain heart infusion (BHI) culture supernatants using ammonium sulfate precipitation followed by elution from a Sepharose cation exchange column using a continuous salt gradient (0.1-0.7 M NaCl). SDS-PAGE of an active column fraction resulted in an electrophoretically pure protein, which corresponded to the growth inhibition of the sensitive Lactobacillus indicator strain in the gel overlay assay. Purified enterocin 62-6 was shown to be heat- and pH-stable, and sensitive to the proteolytic enzymes alpha-chymotrypsin and pepsin. Results from mass spectrometry suggested that it comprised two peptides of 5206 and 5219+/-1 Da, which was confirmed by DNA sequence analysis. The characteristics of enterocin 62-6 as a small, heat- and pH-stable, cationic, hydrophobic, two-peptide, plasmid-borne bacteriocin, with an inhibitory spectrum against a broad range of Gram-positive but not Gram-negative bacteria, were consistent with its classification as a class IIc bacteriocin. Furthermore, its wide spectrum of growth inhibitory activity against Gram-positive bacteria of vaginal origin including lactobacilli, and stability under the acidic conditions of the vagina, are consistent with our hypothesis that it could have potential significance in disrupting the ecology of the vaginal tract and pave the way for the establishment of the abnormal microbiota associated with the vaginal syndrome bacterial vaginosis. This is the first class IIc bacteriocin produced by a strain of E. faecium of vaginal origin to be characterized.
ABSTRACT Biogeophysical investigations over the last decade have provided evidence documenting th... more ABSTRACT Biogeophysical investigations over the last decade have provided evidence documenting that geophysical technique can be used to assess in-situ biogeochemical processes. In this study, we investigated a site contaminated by crude oil at Bemidji, Minnesota where intrinsic bioremediation is known to occur and iron is the dormant electron acceptor process.
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