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Genome biology of Actinobacillus pleuropneumoniae JL03, an isolate of serotype 3 prevalent in China.

Xu Z, Zhou Y, Li L, Zhou R, Xiao S, Wan Y, Zhang S, Wang K, Li W, Li L, Jin H, Kang M, Dalai B, Li T, Liu L, Cheng Y, Zhang L, Xu T, Zheng H, Pu S, Wang B, Gu W, Zhang XL, Zhu GF, Wang S, Zhao GP, Chen H - PLoS ONE (2008)

Bottom Line: Preliminary analysis of the genomic sequence and the functions of the encoded proteins not only confirmed the present physiological and pathological knowledge but also offered new insights into the metabolic and virulence characteristics of this important pathogen.In addition to confirming the lack of ApxI toxin, identification of a nonsense mutation in apxIVA and a 5'-proximal truncation of the flp operon deleting both its promoter and the flp1flp2tadV genes have provided convincing scenarios for the low virulence property of JL03.Comparative genomic analysis using the available sequences of other serotypes, probable strain (serotype)-specific genomic islands related to capsular polysaccharides and lipopolysaccharide O-antigen biosyntheses were identified in JL03, which provides a foundation for future research into the mechanisms of serotypic diversity of A. pleuropneumoniae.

View Article: PubMed Central - PubMed

Affiliation: Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.

ABSTRACT
Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, a cause of considerable world wide economic losses in the swine industry. We sequenced the complete genome of A. pleuropneumoniae, JL03, an isolate of serotype 3 prevalent in China. Its genome is a single chromosome of 2,242,062 base pairs containing 2,097 predicted protein-coding sequences, six ribosomal rRNA operons, and 63 tRNA genes. Preliminary analysis of the genomic sequence and the functions of the encoded proteins not only confirmed the present physiological and pathological knowledge but also offered new insights into the metabolic and virulence characteristics of this important pathogen. We identified a full spectrum of genes related to its characteristic chemoheterotrophic catabolism of fermentation and respiration with an incomplete TCA system for anabolism. In addition to confirming the lack of ApxI toxin, identification of a nonsense mutation in apxIVA and a 5'-proximal truncation of the flp operon deleting both its promoter and the flp1flp2tadV genes have provided convincing scenarios for the low virulence property of JL03. Comparative genomic analysis using the available sequences of other serotypes, probable strain (serotype)-specific genomic islands related to capsular polysaccharides and lipopolysaccharide O-antigen biosyntheses were identified in JL03, which provides a foundation for future research into the mechanisms of serotypic diversity of A. pleuropneumoniae.

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Related in: MedlinePlus

A schematic diagram of virulence factors located in virtual cell environment of A. pleuropneumoniae JL03.CDSs corresponding to the illustrated proteins with designated APJL numbers are listed in Table 5 (adherence and secretion relevant genes), Table 6 (capsule polysaccharide relevant genes), Table 7 (lipopolysaccharide relevant genes), Table S3 (iron relevant genes) and S4 (the rest portion relevant genes). Proteins involved in iron uptake, transport and regulation are colored in yellow.
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pone-0001450-g005: A schematic diagram of virulence factors located in virtual cell environment of A. pleuropneumoniae JL03.CDSs corresponding to the illustrated proteins with designated APJL numbers are listed in Table 5 (adherence and secretion relevant genes), Table 6 (capsule polysaccharide relevant genes), Table 7 (lipopolysaccharide relevant genes), Table S3 (iron relevant genes) and S4 (the rest portion relevant genes). Proteins involved in iron uptake, transport and regulation are colored in yellow.

Mentions: Iron is essential for bacterial growth and acts as an environmental signal that regulates the expression of many virulence factors [3]. Mammals have evolved a mechanism to reduce the availability of iron to potential bacterial pathogens by using of very-high-affinity iron-chelating molecules, while host-adapted pathogens have accordingly evolved means to use these iron-bearing molecules as an iron source [46]. It is known that A. pleuropneumoniae can use porcine transferrin, hemoglobin and ferrichrome [3], [46]. Approximately 2.6% (55 genes) of the JL03 genome are involved in iron uptake with additional 5 related pseudogenes likely impaired by mutations. Comparing with the genomes of other Pasteurellaceae members, large proportion of genes involved in iron metabolism seems common at least within the family (Table S3). These iron metabolism related proteins are highly conserved between JL03 and L20 except for TbpB1 (APJL1598) and FhuA (APJL2066). An analogous cell model of some iron-related protein complexes and other virulence factors is illustrated in Figure 5.


Genome biology of Actinobacillus pleuropneumoniae JL03, an isolate of serotype 3 prevalent in China.

Xu Z, Zhou Y, Li L, Zhou R, Xiao S, Wan Y, Zhang S, Wang K, Li W, Li L, Jin H, Kang M, Dalai B, Li T, Liu L, Cheng Y, Zhang L, Xu T, Zheng H, Pu S, Wang B, Gu W, Zhang XL, Zhu GF, Wang S, Zhao GP, Chen H - PLoS ONE (2008)

A schematic diagram of virulence factors located in virtual cell environment of A. pleuropneumoniae JL03.CDSs corresponding to the illustrated proteins with designated APJL numbers are listed in Table 5 (adherence and secretion relevant genes), Table 6 (capsule polysaccharide relevant genes), Table 7 (lipopolysaccharide relevant genes), Table S3 (iron relevant genes) and S4 (the rest portion relevant genes). Proteins involved in iron uptake, transport and regulation are colored in yellow.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2175527&req=5

pone-0001450-g005: A schematic diagram of virulence factors located in virtual cell environment of A. pleuropneumoniae JL03.CDSs corresponding to the illustrated proteins with designated APJL numbers are listed in Table 5 (adherence and secretion relevant genes), Table 6 (capsule polysaccharide relevant genes), Table 7 (lipopolysaccharide relevant genes), Table S3 (iron relevant genes) and S4 (the rest portion relevant genes). Proteins involved in iron uptake, transport and regulation are colored in yellow.
Mentions: Iron is essential for bacterial growth and acts as an environmental signal that regulates the expression of many virulence factors [3]. Mammals have evolved a mechanism to reduce the availability of iron to potential bacterial pathogens by using of very-high-affinity iron-chelating molecules, while host-adapted pathogens have accordingly evolved means to use these iron-bearing molecules as an iron source [46]. It is known that A. pleuropneumoniae can use porcine transferrin, hemoglobin and ferrichrome [3], [46]. Approximately 2.6% (55 genes) of the JL03 genome are involved in iron uptake with additional 5 related pseudogenes likely impaired by mutations. Comparing with the genomes of other Pasteurellaceae members, large proportion of genes involved in iron metabolism seems common at least within the family (Table S3). These iron metabolism related proteins are highly conserved between JL03 and L20 except for TbpB1 (APJL1598) and FhuA (APJL2066). An analogous cell model of some iron-related protein complexes and other virulence factors is illustrated in Figure 5.

Bottom Line: Preliminary analysis of the genomic sequence and the functions of the encoded proteins not only confirmed the present physiological and pathological knowledge but also offered new insights into the metabolic and virulence characteristics of this important pathogen.In addition to confirming the lack of ApxI toxin, identification of a nonsense mutation in apxIVA and a 5'-proximal truncation of the flp operon deleting both its promoter and the flp1flp2tadV genes have provided convincing scenarios for the low virulence property of JL03.Comparative genomic analysis using the available sequences of other serotypes, probable strain (serotype)-specific genomic islands related to capsular polysaccharides and lipopolysaccharide O-antigen biosyntheses were identified in JL03, which provides a foundation for future research into the mechanisms of serotypic diversity of A. pleuropneumoniae.

View Article: PubMed Central - PubMed

Affiliation: Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.

ABSTRACT
Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, a cause of considerable world wide economic losses in the swine industry. We sequenced the complete genome of A. pleuropneumoniae, JL03, an isolate of serotype 3 prevalent in China. Its genome is a single chromosome of 2,242,062 base pairs containing 2,097 predicted protein-coding sequences, six ribosomal rRNA operons, and 63 tRNA genes. Preliminary analysis of the genomic sequence and the functions of the encoded proteins not only confirmed the present physiological and pathological knowledge but also offered new insights into the metabolic and virulence characteristics of this important pathogen. We identified a full spectrum of genes related to its characteristic chemoheterotrophic catabolism of fermentation and respiration with an incomplete TCA system for anabolism. In addition to confirming the lack of ApxI toxin, identification of a nonsense mutation in apxIVA and a 5'-proximal truncation of the flp operon deleting both its promoter and the flp1flp2tadV genes have provided convincing scenarios for the low virulence property of JL03. Comparative genomic analysis using the available sequences of other serotypes, probable strain (serotype)-specific genomic islands related to capsular polysaccharides and lipopolysaccharide O-antigen biosyntheses were identified in JL03, which provides a foundation for future research into the mechanisms of serotypic diversity of A. pleuropneumoniae.

Show MeSH
Related in: MedlinePlus