The Experts below are selected from a list of 26085 Experts worldwide ranked by ideXlab platform
Claudia S L Vicente - One of the best experts on this subject based on the ideXlab platform.
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the genome and genetics of a high oxidative stress tolerant Serratia sp lcn16 isolated from the plant parasitic nematode bursaphelenchus xylophilus
BMC Genomics, 2016Co-Authors: Yoriko Ikuyo, Manuel Mota, Claudia S L Vicente, Francisco X Nascimento, Peter J A Cock, Koichi HasegawaAbstract:Pine wilt disease (PWD) is a worldwide threat to pine forests, and is caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus. Bacteria are known to be associated with PWN and may have an important role in PWD. Serratia sp. LCN16 is a PWN-associated bacterium, highly resistant to oxidative stress in vitro, and which beneficially contributes to the PWN survival under these conditions. Oxidative stress is generated as a part of the basal defense mechanism used by plants to combat pathogenic invasion. Here, we studied the biology of Serratia sp. LCN16 through genome analyses, and further investigated, using reverse genetics, the role of two genes directly involved in the neutralization of H2O2, namely the H2O2 transcriptional factor oxyR; and the H2O2-targeting enzyme, catalase katA. Serratia sp. LCN16 is phylogenetically most closely related to the phytosphere group of Serratia, which includes S. proteamaculans, S. grimessi and S. liquefaciens. Likewise, Serratia sp. LCN16 shares many features with endophytes (plant-associated bacteria), such as genes coding for plant polymer degrading enzymes, iron uptake/transport, siderophore and phytohormone synthesis, aromatic compound degradation and detoxification enzymes. OxyR and KatA are directly involved in the high tolerance to H2O2 of Serratia sp. LCN16. Under oxidative stress, Serratia sp. LCN16 expresses katA independently of OxyR in contrast with katG which is under positive regulation of OxyR. Serratia sp. LCN16 mutants for oxyR (oxyR::int(614)) and katA (katA::int(808)) were sensitive to H2O2 in relation with wild-type, and both failed to protect the PWN from H2O2-stress exposure. Moreover, both mutants showed different phenotypes in terms of biofilm production and swimming/swarming behaviors. This study provides new insights into the biology of PWN-associated bacteria Serratia sp. LCN16 and its extreme resistance to oxidative stress conditions, encouraging further research on the potential role of this bacterium in interaction with PWN in planta environment.
Louis S Tisa - One of the best experts on this subject based on the ideXlab platform.
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inactivation of the major hemolysin gene influences expression of the nonribosomal peptide synthetase gene swra in the insect pathogen Serratia sp strain scbi
Journal of Bacteriology, 2017Co-Authors: Lauren M Petersen, Kaitlyn Lacourse, Tim A Schoner, Helge B Bode, Louis S TisaAbstract:Hemolysins are important virulence factors for many bacterial pathogens, including Serratia marcescens The role of the major hemolysin gene in the insect pathogen Serratia sp. strain SCBI was investigated using both forward and reverse-genetics approaches. Introduction of the major hemolysin gene into Escherichia coli resulted in a gain of both virulence and hemolytic activity. Inactivation of this hemolysin in Serratia sp. SCBI resulted in a loss of hemolysis but did not attenuate insecticidal activity. Unexpectedly, inactivation of the hemolysin gene in Serratia sp. SCBI resulted in significantly increased motility and increased antimicrobial activity. Reverse transcription-quantitative PCR (qRT-PCR) analysis of mutants with a disrupted hemolysin gene showed a dramatic increase in mRNA levels of a nonribosomal peptide synthetase gene, swrA, which produces the surfactant serrawettin W2. Mutation of the swrA gene in Serratia sp. SCBI resulted in highly varied antibiotic activity, motility, virulence, and hemolysis phenotypes that were dependent on the site of disruption within this 17.75-kb gene. When introduced into E. coli, swrA increases rates of motility and confers antimicrobial activity. While it is unclear how inactivation of the major hemolysin gene influences the expression of swrA, these results suggest that swrA plays an important role in motility and antimicrobial activity in Serratia sp. SCBI.IMPORTANCE The opportunistic Gram-negative bacteria of the genus Serratia are widespread in the environment and can cause human illness. A comparative genomics analysis between Serratia marcescens and a new Serratia species from South Africa, termed Serratia sp. strain SCBI, shows that these two organisms are closely related but differ in pathogenesis. S. marcescens kills Caenorhabditis nematodes, while Serratia sp. SCBI is not harmful and forms a beneficial association with them. This distinction presented the opportunity to investigate potential differences in regulation of common virulence mechanisms between these two species. With the emergence of antibiotic-resistant microorganisms, there is a widespread need to understand the regulation of pathogenesis. The significance of this study is the presentation of evidence for cross-pathway regulation of virulence factors and how the elimination of one mechanism may be compensated for by the upregulation of others.
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influence of temperature on the physiology and virulence of the insect pathogen Serratia sp strain scbi
Applied and Environmental Microbiology, 2012Co-Authors: Lauren M Petersen, Louis S TisaAbstract:The physiology of a newly recognized Serratia species, termed South African Caenorhabditis briggsae Isolate (SCBI), which is both a nematode mutualist and an insect pathogen, was investigated and compared to that of Serratia marcescens Db11, a broad-host-range pathogen. The two Serratia strains had comparable levels of virulence for Manduca sexta and similar cytotoxic activity patterns, but motility and lipase and hemolytic activities differed significantly between them.
Koichi Hasegawa - One of the best experts on this subject based on the ideXlab platform.
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the genome and genetics of a high oxidative stress tolerant Serratia sp lcn16 isolated from the plant parasitic nematode bursaphelenchus xylophilus
BMC Genomics, 2016Co-Authors: Yoriko Ikuyo, Manuel Mota, Claudia S L Vicente, Francisco X Nascimento, Peter J A Cock, Koichi HasegawaAbstract:Pine wilt disease (PWD) is a worldwide threat to pine forests, and is caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus. Bacteria are known to be associated with PWN and may have an important role in PWD. Serratia sp. LCN16 is a PWN-associated bacterium, highly resistant to oxidative stress in vitro, and which beneficially contributes to the PWN survival under these conditions. Oxidative stress is generated as a part of the basal defense mechanism used by plants to combat pathogenic invasion. Here, we studied the biology of Serratia sp. LCN16 through genome analyses, and further investigated, using reverse genetics, the role of two genes directly involved in the neutralization of H2O2, namely the H2O2 transcriptional factor oxyR; and the H2O2-targeting enzyme, catalase katA. Serratia sp. LCN16 is phylogenetically most closely related to the phytosphere group of Serratia, which includes S. proteamaculans, S. grimessi and S. liquefaciens. Likewise, Serratia sp. LCN16 shares many features with endophytes (plant-associated bacteria), such as genes coding for plant polymer degrading enzymes, iron uptake/transport, siderophore and phytohormone synthesis, aromatic compound degradation and detoxification enzymes. OxyR and KatA are directly involved in the high tolerance to H2O2 of Serratia sp. LCN16. Under oxidative stress, Serratia sp. LCN16 expresses katA independently of OxyR in contrast with katG which is under positive regulation of OxyR. Serratia sp. LCN16 mutants for oxyR (oxyR::int(614)) and katA (katA::int(808)) were sensitive to H2O2 in relation with wild-type, and both failed to protect the PWN from H2O2-stress exposure. Moreover, both mutants showed different phenotypes in terms of biofilm production and swimming/swarming behaviors. This study provides new insights into the biology of PWN-associated bacteria Serratia sp. LCN16 and its extreme resistance to oxidative stress conditions, encouraging further research on the potential role of this bacterium in interaction with PWN in planta environment.
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Additional file 2: Figure S1. of The genome and genetics of a high oxidative stress tolerant Serratia sp. LCN16 isolated from the plant parasitic nematode Bursaphelenchus xylophilus
2016Co-Authors: Claudia Vicente, Francisco Nascimento, Yoriko Ikuyo, Peter Cock, Manuel Mota, Koichi HasegawaAbstract:Comparison of Serratia sp. LCN16 genome and the closest Serratia representatives, S. proteamaculans 568 (Spro568) and S. liquefaciens ATCC 27592. Genome to genome alignment conducted using MAUVE software [64]. S1A figure shows the syntenic regions (locally collinear blocks, LCD) between genomes. In each LCD, the height of the similarity profile indicates the level of conservation in that genome region. White areas indicate specific sequences of the genome. The genome rearrangements are indicated as different colored lines. S1B figure presents the similarities between genomes are indicate as follows: purple indicates conserved regions in all genomes; green indicates Serratia sp. LCN16 and ATCC 27592 genomes (highlighted with red arrow); reds indicate Serratia sp. LCN16 and Spro568 genomes; and orange, conservation between Spro568 and ATCC 27592. (PDF 3065 kb
Manuel Mota - One of the best experts on this subject based on the ideXlab platform.
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the genome and genetics of a high oxidative stress tolerant Serratia sp lcn16 isolated from the plant parasitic nematode bursaphelenchus xylophilus
BMC Genomics, 2016Co-Authors: Yoriko Ikuyo, Manuel Mota, Claudia S L Vicente, Francisco X Nascimento, Peter J A Cock, Koichi HasegawaAbstract:Pine wilt disease (PWD) is a worldwide threat to pine forests, and is caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus. Bacteria are known to be associated with PWN and may have an important role in PWD. Serratia sp. LCN16 is a PWN-associated bacterium, highly resistant to oxidative stress in vitro, and which beneficially contributes to the PWN survival under these conditions. Oxidative stress is generated as a part of the basal defense mechanism used by plants to combat pathogenic invasion. Here, we studied the biology of Serratia sp. LCN16 through genome analyses, and further investigated, using reverse genetics, the role of two genes directly involved in the neutralization of H2O2, namely the H2O2 transcriptional factor oxyR; and the H2O2-targeting enzyme, catalase katA. Serratia sp. LCN16 is phylogenetically most closely related to the phytosphere group of Serratia, which includes S. proteamaculans, S. grimessi and S. liquefaciens. Likewise, Serratia sp. LCN16 shares many features with endophytes (plant-associated bacteria), such as genes coding for plant polymer degrading enzymes, iron uptake/transport, siderophore and phytohormone synthesis, aromatic compound degradation and detoxification enzymes. OxyR and KatA are directly involved in the high tolerance to H2O2 of Serratia sp. LCN16. Under oxidative stress, Serratia sp. LCN16 expresses katA independently of OxyR in contrast with katG which is under positive regulation of OxyR. Serratia sp. LCN16 mutants for oxyR (oxyR::int(614)) and katA (katA::int(808)) were sensitive to H2O2 in relation with wild-type, and both failed to protect the PWN from H2O2-stress exposure. Moreover, both mutants showed different phenotypes in terms of biofilm production and swimming/swarming behaviors. This study provides new insights into the biology of PWN-associated bacteria Serratia sp. LCN16 and its extreme resistance to oxidative stress conditions, encouraging further research on the potential role of this bacterium in interaction with PWN in planta environment.
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Additional file 2: Figure S1. of The genome and genetics of a high oxidative stress tolerant Serratia sp. LCN16 isolated from the plant parasitic nematode Bursaphelenchus xylophilus
2016Co-Authors: Claudia Vicente, Francisco Nascimento, Yoriko Ikuyo, Peter Cock, Manuel Mota, Koichi HasegawaAbstract:Comparison of Serratia sp. LCN16 genome and the closest Serratia representatives, S. proteamaculans 568 (Spro568) and S. liquefaciens ATCC 27592. Genome to genome alignment conducted using MAUVE software [64]. S1A figure shows the syntenic regions (locally collinear blocks, LCD) between genomes. In each LCD, the height of the similarity profile indicates the level of conservation in that genome region. White areas indicate specific sequences of the genome. The genome rearrangements are indicated as different colored lines. S1B figure presents the similarities between genomes are indicate as follows: purple indicates conserved regions in all genomes; green indicates Serratia sp. LCN16 and ATCC 27592 genomes (highlighted with red arrow); reds indicate Serratia sp. LCN16 and Spro568 genomes; and orange, conservation between Spro568 and ATCC 27592. (PDF 3065 kb
Lauren M Petersen - One of the best experts on this subject based on the ideXlab platform.
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inactivation of the major hemolysin gene influences expression of the nonribosomal peptide synthetase gene swra in the insect pathogen Serratia sp strain scbi
Journal of Bacteriology, 2017Co-Authors: Lauren M Petersen, Kaitlyn Lacourse, Tim A Schoner, Helge B Bode, Louis S TisaAbstract:Hemolysins are important virulence factors for many bacterial pathogens, including Serratia marcescens The role of the major hemolysin gene in the insect pathogen Serratia sp. strain SCBI was investigated using both forward and reverse-genetics approaches. Introduction of the major hemolysin gene into Escherichia coli resulted in a gain of both virulence and hemolytic activity. Inactivation of this hemolysin in Serratia sp. SCBI resulted in a loss of hemolysis but did not attenuate insecticidal activity. Unexpectedly, inactivation of the hemolysin gene in Serratia sp. SCBI resulted in significantly increased motility and increased antimicrobial activity. Reverse transcription-quantitative PCR (qRT-PCR) analysis of mutants with a disrupted hemolysin gene showed a dramatic increase in mRNA levels of a nonribosomal peptide synthetase gene, swrA, which produces the surfactant serrawettin W2. Mutation of the swrA gene in Serratia sp. SCBI resulted in highly varied antibiotic activity, motility, virulence, and hemolysis phenotypes that were dependent on the site of disruption within this 17.75-kb gene. When introduced into E. coli, swrA increases rates of motility and confers antimicrobial activity. While it is unclear how inactivation of the major hemolysin gene influences the expression of swrA, these results suggest that swrA plays an important role in motility and antimicrobial activity in Serratia sp. SCBI.IMPORTANCE The opportunistic Gram-negative bacteria of the genus Serratia are widespread in the environment and can cause human illness. A comparative genomics analysis between Serratia marcescens and a new Serratia species from South Africa, termed Serratia sp. strain SCBI, shows that these two organisms are closely related but differ in pathogenesis. S. marcescens kills Caenorhabditis nematodes, while Serratia sp. SCBI is not harmful and forms a beneficial association with them. This distinction presented the opportunity to investigate potential differences in regulation of common virulence mechanisms between these two species. With the emergence of antibiotic-resistant microorganisms, there is a widespread need to understand the regulation of pathogenesis. The significance of this study is the presentation of evidence for cross-pathway regulation of virulence factors and how the elimination of one mechanism may be compensated for by the upregulation of others.
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influence of temperature on the physiology and virulence of the insect pathogen Serratia sp strain scbi
Applied and Environmental Microbiology, 2012Co-Authors: Lauren M Petersen, Louis S TisaAbstract:The physiology of a newly recognized Serratia species, termed South African Caenorhabditis briggsae Isolate (SCBI), which is both a nematode mutualist and an insect pathogen, was investigated and compared to that of Serratia marcescens Db11, a broad-host-range pathogen. The two Serratia strains had comparable levels of virulence for Manduca sexta and similar cytotoxic activity patterns, but motility and lipase and hemolytic activities differed significantly between them.
