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Growth phase-associated changes in the proteome and transcriptome of Lactobacillus rhamnosus GG in industrial-type whey medium.

Laakso K, Koskenniemi K, Koponen J, Kankainen M, Surakka A, Salusjärvi T, Auvinen P, Savijoki K, Nyman TA, Kalkkinen N, Tynkkynen S, Varmanen P - Microb Biotechnol (2011)

Bottom Line: Of the significantly differentially produced proteins, 61 were associated with alterations at the transcript level.The most remarkable growth phase-dependent changes occurred during the transition from the exponential to the stationary growth phase and were associated with the shift from glucose fermentation to galactose utilization and the transition from homolactic to mixed acid fermentation.Furthermore, several genes encoding proteins proposed to promote the survival and persistence of L. rhamnosus GG in the host and proteins that directly contribute to human health showed temporal changes in expression.

View Article: PubMed Central - PubMed

Affiliation: Research and Development, Valio Ltd, Helsinki, Finland.

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Related in: MedlinePlus

Growth curve of L. rhamnosus GG in whey medium at 37°C at pH 5.8. Cell density values represent the mean of four individual pH‐controlled bioreactor cultivations, and error bars represent the standard deviation. RNA samples were taken at five different time points representing mid‐exponential, late exponential, stationary transition point, early stationary and late stationary phases, while protein samples were collected at four different time points (the same as the RNA sampling phases, excluding the stationary transition point). The time points at which the RNA (R) and protein (P) samples were taken are indicated by arrows.
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f1: Growth curve of L. rhamnosus GG in whey medium at 37°C at pH 5.8. Cell density values represent the mean of four individual pH‐controlled bioreactor cultivations, and error bars represent the standard deviation. RNA samples were taken at five different time points representing mid‐exponential, late exponential, stationary transition point, early stationary and late stationary phases, while protein samples were collected at four different time points (the same as the RNA sampling phases, excluding the stationary transition point). The time points at which the RNA (R) and protein (P) samples were taken are indicated by arrows.

Mentions: In the present study, 2‐D DIGE and whole‐genome DNA microarrays were used to determine how global gene expression in the widely used probiotic, L. rhamnosus GG, changed over time during growth in industrial‐type whey medium under strictly defined bioreactor conditions (Fig. 1). Overall, the transcript levels of 636 genes were significantly changed (≥ 2‐fold difference, P ≤ 0.01) at one or more time points, representing 22% of the complete genome of L. rhamnosus GG (Fig. 2). This is comparable to results from a previous study, where 21% of the ORFs of the L. acidophilus genome were differentially expressed during shift from exponential to stationary growth phase in skim milk (Azcarate‐Peril et al., 2009). Expression profiles of the 636 significantly differentially expressed genes were clustered into 16 groups (Fig. S1, Table S1). A clear difference could be seen between the transcription profiles of the mid‐exponential (4 h) and stationary growth phases (20 and 31 h), although only a few genes were down‐ (five genes) or upregulated (eight genes) during the whole progression of growth (Fig. 2). Interestingly, clusters of orthologous groups (COGs) classification of significantly differentially expressed genes showed that the majority of genes regulated at time points 12, 16, 20 and 31 h, compared with the 4 h time point, could not be included in any COG category (Fig. 3). At the 20 h time point, Carbohydrate transport and metabolism (G), Energy production and conversion (C) and Transcription (K) seemed to be coordinately upregulated when compared with 4 h, while most of the downregulated genes were involved in Amino acid transport and metabolism (E) or were categorized as ‘General function prediction only’ (R). At 31 h, most of the upregulated genes were assigned to the G and C categories, and the majority of downregulated genes belonged to the Translation, ribosomal structure and biogenesis (J) and Nucleotide transport and metabolism (F) categories.


Growth phase-associated changes in the proteome and transcriptome of Lactobacillus rhamnosus GG in industrial-type whey medium.

Laakso K, Koskenniemi K, Koponen J, Kankainen M, Surakka A, Salusjärvi T, Auvinen P, Savijoki K, Nyman TA, Kalkkinen N, Tynkkynen S, Varmanen P - Microb Biotechnol (2011)

Growth curve of L. rhamnosus GG in whey medium at 37°C at pH 5.8. Cell density values represent the mean of four individual pH‐controlled bioreactor cultivations, and error bars represent the standard deviation. RNA samples were taken at five different time points representing mid‐exponential, late exponential, stationary transition point, early stationary and late stationary phases, while protein samples were collected at four different time points (the same as the RNA sampling phases, excluding the stationary transition point). The time points at which the RNA (R) and protein (P) samples were taken are indicated by arrows.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815411&req=5

f1: Growth curve of L. rhamnosus GG in whey medium at 37°C at pH 5.8. Cell density values represent the mean of four individual pH‐controlled bioreactor cultivations, and error bars represent the standard deviation. RNA samples were taken at five different time points representing mid‐exponential, late exponential, stationary transition point, early stationary and late stationary phases, while protein samples were collected at four different time points (the same as the RNA sampling phases, excluding the stationary transition point). The time points at which the RNA (R) and protein (P) samples were taken are indicated by arrows.
Mentions: In the present study, 2‐D DIGE and whole‐genome DNA microarrays were used to determine how global gene expression in the widely used probiotic, L. rhamnosus GG, changed over time during growth in industrial‐type whey medium under strictly defined bioreactor conditions (Fig. 1). Overall, the transcript levels of 636 genes were significantly changed (≥ 2‐fold difference, P ≤ 0.01) at one or more time points, representing 22% of the complete genome of L. rhamnosus GG (Fig. 2). This is comparable to results from a previous study, where 21% of the ORFs of the L. acidophilus genome were differentially expressed during shift from exponential to stationary growth phase in skim milk (Azcarate‐Peril et al., 2009). Expression profiles of the 636 significantly differentially expressed genes were clustered into 16 groups (Fig. S1, Table S1). A clear difference could be seen between the transcription profiles of the mid‐exponential (4 h) and stationary growth phases (20 and 31 h), although only a few genes were down‐ (five genes) or upregulated (eight genes) during the whole progression of growth (Fig. 2). Interestingly, clusters of orthologous groups (COGs) classification of significantly differentially expressed genes showed that the majority of genes regulated at time points 12, 16, 20 and 31 h, compared with the 4 h time point, could not be included in any COG category (Fig. 3). At the 20 h time point, Carbohydrate transport and metabolism (G), Energy production and conversion (C) and Transcription (K) seemed to be coordinately upregulated when compared with 4 h, while most of the downregulated genes were involved in Amino acid transport and metabolism (E) or were categorized as ‘General function prediction only’ (R). At 31 h, most of the upregulated genes were assigned to the G and C categories, and the majority of downregulated genes belonged to the Translation, ribosomal structure and biogenesis (J) and Nucleotide transport and metabolism (F) categories.

Bottom Line: Of the significantly differentially produced proteins, 61 were associated with alterations at the transcript level.The most remarkable growth phase-dependent changes occurred during the transition from the exponential to the stationary growth phase and were associated with the shift from glucose fermentation to galactose utilization and the transition from homolactic to mixed acid fermentation.Furthermore, several genes encoding proteins proposed to promote the survival and persistence of L. rhamnosus GG in the host and proteins that directly contribute to human health showed temporal changes in expression.

View Article: PubMed Central - PubMed

Affiliation: Research and Development, Valio Ltd, Helsinki, Finland.

Show MeSH
Related in: MedlinePlus