Limits...
Extensive adaptive changes occur in the transcriptome of Streptococcus agalactiae (group B streptococcus) in response to incubation with human blood.

Mereghetti L, Sitkiewicz I, Green NM, Musser JM - PLoS ONE (2008)

Bottom Line: Most (83%) of the significantly altered transcripts were down-regulated after 30 minutes of incubation in blood, and all functional categories of genes were abundantly represented.Extensive transcript changes also occurred for genes involved in carbohydrate metabolism, including multi-functional proteins and regulators putatively involved in pathogenesis.Taken together, the data provide extensive new information about transcriptional adaptation of GBS exposed to human blood, a crucial step during GBS pathogenesis in invasive diseases, and identify many new leads for molecular pathogenesis research.

View Article: PubMed Central - PubMed

Affiliation: Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology, The Methodist Hospital Research Institute, Houston, Texas, United States of America.

ABSTRACT
To enhance understanding of how Streptococcus agalactiae (group B streptococcus, GBS) adapts during invasive infection, we performed a whole-genome transcriptome analysis after incubation with whole human blood. Global changes occurred in the GBS transcriptome rapidly in response to blood contact following shift from growth in a rich laboratory medium. Most (83%) of the significantly altered transcripts were down-regulated after 30 minutes of incubation in blood, and all functional categories of genes were abundantly represented. We observed complex dynamic changes in the expression of transcriptional regulators and stress response genes that allow GBS to rapidly adapt to blood. The transcripts of relatively few proven virulence genes were up-regulated during the first 90 minutes. However, a key discovery was that genes encoding proteins involved in interaction with the host coagulation/fibrinolysis system and bacterial-host interactions were rapidly up-regulated. Extensive transcript changes also occurred for genes involved in carbohydrate metabolism, including multi-functional proteins and regulators putatively involved in pathogenesis. Finally, we discovered that an incubation temperature closer to that occurring in patients with severe infection and high fever (40 degrees C) induced additional differences in the GBS transcriptome relative to normal body temperature (37 degrees C). Taken together, the data provide extensive new information about transcriptional adaptation of GBS exposed to human blood, a crucial step during GBS pathogenesis in invasive diseases, and identify many new leads for molecular pathogenesis research.

Show MeSH

Related in: MedlinePlus

Differential regulation of virulence gene expression in GBS strain NEM316 during incubation with human blood.The scatter diagram displays normalized spot intensities of the microarray analysis from proven and putative GBS virulence genes. Genes of interest are in blue or green; other proven and putative GBS virulence factors are in gray. (a) After 30 min of incubation with blood at 37°C (time 1 relative to time 0). Higher level of transcription is shown for genes encoding proteins with LPXTG motifs: gbs0428, gbs1087 (fbsA), gbs1420 (bsp), and gbs2018 (bibA); and genes encoding proteins implicated in binding/activation of plasminogen: gbs0608 (eno), gbs1811 (gapC), and gbs1195 (ska). Numerous other proven and putative virulence genes were either down-regulated or their transcription was not modified. (b) After 90 min of incubation with blood at 37°C (time 2 relative to time 0). Six of the previous seven genes (except gbs1087-fbsA) remained up-regulated after 90 min of incubation with blood. Levels of transcription of the other proven and putative virulence genes were higher relative to incubation of 30 min.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2519835&req=5

pone-0003143-g004: Differential regulation of virulence gene expression in GBS strain NEM316 during incubation with human blood.The scatter diagram displays normalized spot intensities of the microarray analysis from proven and putative GBS virulence genes. Genes of interest are in blue or green; other proven and putative GBS virulence factors are in gray. (a) After 30 min of incubation with blood at 37°C (time 1 relative to time 0). Higher level of transcription is shown for genes encoding proteins with LPXTG motifs: gbs0428, gbs1087 (fbsA), gbs1420 (bsp), and gbs2018 (bibA); and genes encoding proteins implicated in binding/activation of plasminogen: gbs0608 (eno), gbs1811 (gapC), and gbs1195 (ska). Numerous other proven and putative virulence genes were either down-regulated or their transcription was not modified. (b) After 90 min of incubation with blood at 37°C (time 2 relative to time 0). Six of the previous seven genes (except gbs1087-fbsA) remained up-regulated after 90 min of incubation with blood. Levels of transcription of the other proven and putative virulence genes were higher relative to incubation of 30 min.

Mentions: Relatively few proven virulence genes were significantly up-regulated in response to culturing in human blood. Most known and putative virulence genes were either down-regulated or their transcript level was not altered, although after 90 min of incubation in blood the level of many transcripts was increased (Fig. 4). Importantly, we observed up-regulation of four genes encoding LPXTG proteins after 30 min of incubation in blood, including gbs0428, gbs1087 (fbsA) encoding a major receptor for fibrinogen, gbs1420 (bsp) which encodes a putative choline-binding protein, and gbs2018 (bibA) which encodes a protein that binds to human C4-binding protein and contributes to survival in human blood [10] (Fig. 4A and Table 2). Interestingly, the level of transcripts of three genes encoding proteins implicated in binding or activation of plasminogen also were higher in human blood than in THY, including gbs0608 (eno) encoding enolase, gbs1811 (gapC) encoding glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and gbs1195 (ska) encoding a secreted protein similar to streptokinase [26] (Fig. 4A and Table 2). After 90 minutes of incubation, six of these seven genes (except gbs1087-fbsA) remained up-regulated relative to time 0 (Fig. 4B and Table 2).


Extensive adaptive changes occur in the transcriptome of Streptococcus agalactiae (group B streptococcus) in response to incubation with human blood.

Mereghetti L, Sitkiewicz I, Green NM, Musser JM - PLoS ONE (2008)

Differential regulation of virulence gene expression in GBS strain NEM316 during incubation with human blood.The scatter diagram displays normalized spot intensities of the microarray analysis from proven and putative GBS virulence genes. Genes of interest are in blue or green; other proven and putative GBS virulence factors are in gray. (a) After 30 min of incubation with blood at 37°C (time 1 relative to time 0). Higher level of transcription is shown for genes encoding proteins with LPXTG motifs: gbs0428, gbs1087 (fbsA), gbs1420 (bsp), and gbs2018 (bibA); and genes encoding proteins implicated in binding/activation of plasminogen: gbs0608 (eno), gbs1811 (gapC), and gbs1195 (ska). Numerous other proven and putative virulence genes were either down-regulated or their transcription was not modified. (b) After 90 min of incubation with blood at 37°C (time 2 relative to time 0). Six of the previous seven genes (except gbs1087-fbsA) remained up-regulated after 90 min of incubation with blood. Levels of transcription of the other proven and putative virulence genes were higher relative to incubation of 30 min.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2519835&req=5

pone-0003143-g004: Differential regulation of virulence gene expression in GBS strain NEM316 during incubation with human blood.The scatter diagram displays normalized spot intensities of the microarray analysis from proven and putative GBS virulence genes. Genes of interest are in blue or green; other proven and putative GBS virulence factors are in gray. (a) After 30 min of incubation with blood at 37°C (time 1 relative to time 0). Higher level of transcription is shown for genes encoding proteins with LPXTG motifs: gbs0428, gbs1087 (fbsA), gbs1420 (bsp), and gbs2018 (bibA); and genes encoding proteins implicated in binding/activation of plasminogen: gbs0608 (eno), gbs1811 (gapC), and gbs1195 (ska). Numerous other proven and putative virulence genes were either down-regulated or their transcription was not modified. (b) After 90 min of incubation with blood at 37°C (time 2 relative to time 0). Six of the previous seven genes (except gbs1087-fbsA) remained up-regulated after 90 min of incubation with blood. Levels of transcription of the other proven and putative virulence genes were higher relative to incubation of 30 min.
Mentions: Relatively few proven virulence genes were significantly up-regulated in response to culturing in human blood. Most known and putative virulence genes were either down-regulated or their transcript level was not altered, although after 90 min of incubation in blood the level of many transcripts was increased (Fig. 4). Importantly, we observed up-regulation of four genes encoding LPXTG proteins after 30 min of incubation in blood, including gbs0428, gbs1087 (fbsA) encoding a major receptor for fibrinogen, gbs1420 (bsp) which encodes a putative choline-binding protein, and gbs2018 (bibA) which encodes a protein that binds to human C4-binding protein and contributes to survival in human blood [10] (Fig. 4A and Table 2). Interestingly, the level of transcripts of three genes encoding proteins implicated in binding or activation of plasminogen also were higher in human blood than in THY, including gbs0608 (eno) encoding enolase, gbs1811 (gapC) encoding glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and gbs1195 (ska) encoding a secreted protein similar to streptokinase [26] (Fig. 4A and Table 2). After 90 minutes of incubation, six of these seven genes (except gbs1087-fbsA) remained up-regulated relative to time 0 (Fig. 4B and Table 2).

Bottom Line: Most (83%) of the significantly altered transcripts were down-regulated after 30 minutes of incubation in blood, and all functional categories of genes were abundantly represented.Extensive transcript changes also occurred for genes involved in carbohydrate metabolism, including multi-functional proteins and regulators putatively involved in pathogenesis.Taken together, the data provide extensive new information about transcriptional adaptation of GBS exposed to human blood, a crucial step during GBS pathogenesis in invasive diseases, and identify many new leads for molecular pathogenesis research.

View Article: PubMed Central - PubMed

Affiliation: Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology, The Methodist Hospital Research Institute, Houston, Texas, United States of America.

ABSTRACT
To enhance understanding of how Streptococcus agalactiae (group B streptococcus, GBS) adapts during invasive infection, we performed a whole-genome transcriptome analysis after incubation with whole human blood. Global changes occurred in the GBS transcriptome rapidly in response to blood contact following shift from growth in a rich laboratory medium. Most (83%) of the significantly altered transcripts were down-regulated after 30 minutes of incubation in blood, and all functional categories of genes were abundantly represented. We observed complex dynamic changes in the expression of transcriptional regulators and stress response genes that allow GBS to rapidly adapt to blood. The transcripts of relatively few proven virulence genes were up-regulated during the first 90 minutes. However, a key discovery was that genes encoding proteins involved in interaction with the host coagulation/fibrinolysis system and bacterial-host interactions were rapidly up-regulated. Extensive transcript changes also occurred for genes involved in carbohydrate metabolism, including multi-functional proteins and regulators putatively involved in pathogenesis. Finally, we discovered that an incubation temperature closer to that occurring in patients with severe infection and high fever (40 degrees C) induced additional differences in the GBS transcriptome relative to normal body temperature (37 degrees C). Taken together, the data provide extensive new information about transcriptional adaptation of GBS exposed to human blood, a crucial step during GBS pathogenesis in invasive diseases, and identify many new leads for molecular pathogenesis research.

Show MeSH
Related in: MedlinePlus