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The Multiple DSF-family QS Signals are Synthesized from Carbohydrate and Branched-chain Amino Acids via the FAS Elongation Cycle.

Zhou L, Yu Y, Chen X, Diab AA, Ruan L, He J, Wang H, He YW - Sci Rep (2015)

Bottom Line: Furthermore, our biochemical analyses show that the key DSF synthase RpfF has both thioesterase and dehydratase activities, and uses 3-hydroxydedecanoyl-ACP as a substrate to produce BDSF.Finally, our results show that the classic fatty acid synthesis elongation cycle is required for the biosynthesis of DSF-family signals.Taken all together, these findings establish a general biosynthetic pathway for the DSF-family quorum sensing signals.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.

ABSTRACT
Members of the diffusible signal factor (DSF) family are a novel class of quorum sensing (QS) signals in diverse Gram-negative bacteria. Although previous studies have identified RpfF as a key enzyme for the biosynthesis of DSF family signals, many questions in their biosynthesis remain to be addressed. In this study with the phytopathogen Xanthomonas campestris pv. campestris (Xcc), we show that Xcc produces four DSF-family signals (DSF, BDSF, CDSF and IDSF) during cell culture, and that IDSF is a new functional signal characterized as cis-10-methyl-2-dodecenoic acid. Using a range of defined media, we further demonstrate that Xcc mainly produces BDSF in the presence of carbohydrates; leucine and valine are the primary precursor for DSF biosynthesis; isoleucine is the primary precursor for IDSF biosynthesis. Furthermore, our biochemical analyses show that the key DSF synthase RpfF has both thioesterase and dehydratase activities, and uses 3-hydroxydedecanoyl-ACP as a substrate to produce BDSF. Finally, our results show that the classic fatty acid synthesis elongation cycle is required for the biosynthesis of DSF-family signals. Taken all together, these findings establish a general biosynthetic pathway for the DSF-family quorum sensing signals.

No MeSH data available.


Related in: MedlinePlus

The effects of cerulenin on bacterial growth and the production of BDSF and DSF in Xcc.Bacterial growth (a), supernatant BDSF levels (b) and supernatant DSF levels (c) of the ΔrpfC strain after the addition of cerulenin to NA liquid medium. Cerulenin (3 mg/ml) was added to the cultures at OD600 of 1.0. The data are the means ± one standard deviation of three independent assays. Different letters indicate significant differences between treatments (LSD at P = 0.05).
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f7: The effects of cerulenin on bacterial growth and the production of BDSF and DSF in Xcc.Bacterial growth (a), supernatant BDSF levels (b) and supernatant DSF levels (c) of the ΔrpfC strain after the addition of cerulenin to NA liquid medium. Cerulenin (3 mg/ml) was added to the cultures at OD600 of 1.0. The data are the means ± one standard deviation of three independent assays. Different letters indicate significant differences between treatments (LSD at P = 0.05).

Mentions: To further verify the roles of FAS elongation cycle, cerulenin, an antibiotic that binds in equimolar ratio to long chain 3-keto-acyl-ACP synthases (FabF and FabB)3536, was used to block fatty acid synthesis. The minimum inhibitory concentration of cerulenin on Xcc growth in liquid NA medium was 30 μg/ml. The OD600 of the cell culture treated with cerulenin (30 μg/ml) for 9 h was 2.7, which was a little lower than the OD600 of 3.1 of the untreated cell culture (Fig. 7a). DSF level of the cerulenin-treated culture was 11.5 μM (5.5 × 10−3 μmol/109 cells), and this was about one fifth of 63.5 μM (25.0 × 10−3 μmol/109 cells) which was found in untreated cell cultures (Fig. 7b). Similarly, the BDSF level of the cerulenin-treated culture was 4.3 μM (2.0 × 10−3 μmol/109 cells), and this was about one-fourth of the levels found in the untreated cell cultures (19.1 μM or 7.6 × 10−3 μmol/109 cells) (Fig. 7c). Neither CDSF nor IDSF were detected in the supernatant of cerulenin-treated Xcc culture.


The Multiple DSF-family QS Signals are Synthesized from Carbohydrate and Branched-chain Amino Acids via the FAS Elongation Cycle.

Zhou L, Yu Y, Chen X, Diab AA, Ruan L, He J, Wang H, He YW - Sci Rep (2015)

The effects of cerulenin on bacterial growth and the production of BDSF and DSF in Xcc.Bacterial growth (a), supernatant BDSF levels (b) and supernatant DSF levels (c) of the ΔrpfC strain after the addition of cerulenin to NA liquid medium. Cerulenin (3 mg/ml) was added to the cultures at OD600 of 1.0. The data are the means ± one standard deviation of three independent assays. Different letters indicate significant differences between treatments (LSD at P = 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542539&req=5

f7: The effects of cerulenin on bacterial growth and the production of BDSF and DSF in Xcc.Bacterial growth (a), supernatant BDSF levels (b) and supernatant DSF levels (c) of the ΔrpfC strain after the addition of cerulenin to NA liquid medium. Cerulenin (3 mg/ml) was added to the cultures at OD600 of 1.0. The data are the means ± one standard deviation of three independent assays. Different letters indicate significant differences between treatments (LSD at P = 0.05).
Mentions: To further verify the roles of FAS elongation cycle, cerulenin, an antibiotic that binds in equimolar ratio to long chain 3-keto-acyl-ACP synthases (FabF and FabB)3536, was used to block fatty acid synthesis. The minimum inhibitory concentration of cerulenin on Xcc growth in liquid NA medium was 30 μg/ml. The OD600 of the cell culture treated with cerulenin (30 μg/ml) for 9 h was 2.7, which was a little lower than the OD600 of 3.1 of the untreated cell culture (Fig. 7a). DSF level of the cerulenin-treated culture was 11.5 μM (5.5 × 10−3 μmol/109 cells), and this was about one fifth of 63.5 μM (25.0 × 10−3 μmol/109 cells) which was found in untreated cell cultures (Fig. 7b). Similarly, the BDSF level of the cerulenin-treated culture was 4.3 μM (2.0 × 10−3 μmol/109 cells), and this was about one-fourth of the levels found in the untreated cell cultures (19.1 μM or 7.6 × 10−3 μmol/109 cells) (Fig. 7c). Neither CDSF nor IDSF were detected in the supernatant of cerulenin-treated Xcc culture.

Bottom Line: Furthermore, our biochemical analyses show that the key DSF synthase RpfF has both thioesterase and dehydratase activities, and uses 3-hydroxydedecanoyl-ACP as a substrate to produce BDSF.Finally, our results show that the classic fatty acid synthesis elongation cycle is required for the biosynthesis of DSF-family signals.Taken all together, these findings establish a general biosynthetic pathway for the DSF-family quorum sensing signals.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.

ABSTRACT
Members of the diffusible signal factor (DSF) family are a novel class of quorum sensing (QS) signals in diverse Gram-negative bacteria. Although previous studies have identified RpfF as a key enzyme for the biosynthesis of DSF family signals, many questions in their biosynthesis remain to be addressed. In this study with the phytopathogen Xanthomonas campestris pv. campestris (Xcc), we show that Xcc produces four DSF-family signals (DSF, BDSF, CDSF and IDSF) during cell culture, and that IDSF is a new functional signal characterized as cis-10-methyl-2-dodecenoic acid. Using a range of defined media, we further demonstrate that Xcc mainly produces BDSF in the presence of carbohydrates; leucine and valine are the primary precursor for DSF biosynthesis; isoleucine is the primary precursor for IDSF biosynthesis. Furthermore, our biochemical analyses show that the key DSF synthase RpfF has both thioesterase and dehydratase activities, and uses 3-hydroxydedecanoyl-ACP as a substrate to produce BDSF. Finally, our results show that the classic fatty acid synthesis elongation cycle is required for the biosynthesis of DSF-family signals. Taken all together, these findings establish a general biosynthetic pathway for the DSF-family quorum sensing signals.

No MeSH data available.


Related in: MedlinePlus