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Deciphering the genome of polyphosphate accumulating actinobacterium Microlunatus phosphovorus.

Kawakoshi A, Nakazawa H, Fukada J, Sasagawa M, Katano Y, Nakamura S, Hosoyama A, Sasaki H, Ichikawa N, Hanada S, Kamagata Y, Nakamura K, Yamazaki S, Fujita N - DNA Res. (2012)

Bottom Line: The number of genes for polyP metabolism was greater in M. phosphovorus than in other actinobacteria; it possesses genes for four polyP kinases (ppks), two polyP-dependent glucokinases (ppgks), and three phosphate transporters (pits).Furthermore, M. phosphovorus lacks the phaABC genes for PHA synthesis and the actP gene encoding an acetate/H(+) symporter, both of which play crucial roles in anaerobic PHA accumulation in proteobacterial PAOs.Thus, while the general features of M. phosphovorus regarding aerobic polyP accumulation are similar to those of proteobacterial PAOs, its anaerobic polyP use and PHA synthesis appear to be different.

View Article: PubMed Central - PubMed

Affiliation: Biological Resource Center, National Institute of Technology and Evaluation, 2-10-49 Nishihara, Tokyo 151-0066, Japan.

ABSTRACT
Polyphosphate accumulating organisms (PAOs) belong mostly to Proteobacteria and Actinobacteria and are quite divergent. Under aerobic conditions, they accumulate intracellular polyphosphate (polyP), while they typically synthesize polyhydroxyalkanoates (PHAs) under anaerobic conditions. Many ecological, physiological, and genomic analyses have been performed with proteobacterial PAOs, but few with actinobacterial PAOs. In this study, the whole genome sequence of an actinobacterial PAO, Microlunatus phosphovorus NM-1(T) (NBRC 101784(T)), was determined. The number of genes for polyP metabolism was greater in M. phosphovorus than in other actinobacteria; it possesses genes for four polyP kinases (ppks), two polyP-dependent glucokinases (ppgks), and three phosphate transporters (pits). In contrast, it harbours only a single ppx gene for exopolyphosphatase, although two copies of ppx are generally present in other actinobacteria. Furthermore, M. phosphovorus lacks the phaABC genes for PHA synthesis and the actP gene encoding an acetate/H(+) symporter, both of which play crucial roles in anaerobic PHA accumulation in proteobacterial PAOs. Thus, while the general features of M. phosphovorus regarding aerobic polyP accumulation are similar to those of proteobacterial PAOs, its anaerobic polyP use and PHA synthesis appear to be different.

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Schematic representation of possible pathways for polyP and PHA metabolisms under (A) aerobic and (B) anaerobic conditions. The upper panels in each figure represent models proposed in this study for M. phosphovorus, while the lower ones represent models recognized in proteobacterial species. Not all intermediate reactions are shown in detail.
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DSS020F5: Schematic representation of possible pathways for polyP and PHA metabolisms under (A) aerobic and (B) anaerobic conditions. The upper panels in each figure represent models proposed in this study for M. phosphovorus, while the lower ones represent models recognized in proteobacterial species. Not all intermediate reactions are shown in detail.

Mentions: Based on the genome analysis as described in this report and previous experimental observations, possible pathways of M. phosphovorus that may represent the features of an actinobacterial PAO were summarized in Fig. 5 (upper panels) together with a model proposed in proteobacterial species (lower panels).4,9,11 Under aerobic conditions, M. phosphovorus takes up Pi through a PstSCAB and multiple Pits. PhnCDE rarely exists in non-proteobacteria and is absent in M. phosphovorus. For Pi uptake via Pits, a proton motive force is required. In ‘Ca. Accumulibacter phosphatis’, the electron transport chain of aerobic respiration was proposed for that function11 and may be the primary source of the proton motive force in aerobic M. phosphovorus, as well. The ingested intracellular Pi is then polymerized into polyP by some of the multiple PPK(s) and stored as volutin granules. In M. phosphovorus, PHA may be synthesized through the β-oxidation pathway, whereas proteobacteria degrade PHA and utilize it as an energy source under the aerobic conditions.Figure 5.


Deciphering the genome of polyphosphate accumulating actinobacterium Microlunatus phosphovorus.

Kawakoshi A, Nakazawa H, Fukada J, Sasagawa M, Katano Y, Nakamura S, Hosoyama A, Sasaki H, Ichikawa N, Hanada S, Kamagata Y, Nakamura K, Yamazaki S, Fujita N - DNA Res. (2012)

Schematic representation of possible pathways for polyP and PHA metabolisms under (A) aerobic and (B) anaerobic conditions. The upper panels in each figure represent models proposed in this study for M. phosphovorus, while the lower ones represent models recognized in proteobacterial species. Not all intermediate reactions are shown in detail.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3473371&req=5

DSS020F5: Schematic representation of possible pathways for polyP and PHA metabolisms under (A) aerobic and (B) anaerobic conditions. The upper panels in each figure represent models proposed in this study for M. phosphovorus, while the lower ones represent models recognized in proteobacterial species. Not all intermediate reactions are shown in detail.
Mentions: Based on the genome analysis as described in this report and previous experimental observations, possible pathways of M. phosphovorus that may represent the features of an actinobacterial PAO were summarized in Fig. 5 (upper panels) together with a model proposed in proteobacterial species (lower panels).4,9,11 Under aerobic conditions, M. phosphovorus takes up Pi through a PstSCAB and multiple Pits. PhnCDE rarely exists in non-proteobacteria and is absent in M. phosphovorus. For Pi uptake via Pits, a proton motive force is required. In ‘Ca. Accumulibacter phosphatis’, the electron transport chain of aerobic respiration was proposed for that function11 and may be the primary source of the proton motive force in aerobic M. phosphovorus, as well. The ingested intracellular Pi is then polymerized into polyP by some of the multiple PPK(s) and stored as volutin granules. In M. phosphovorus, PHA may be synthesized through the β-oxidation pathway, whereas proteobacteria degrade PHA and utilize it as an energy source under the aerobic conditions.Figure 5.

Bottom Line: The number of genes for polyP metabolism was greater in M. phosphovorus than in other actinobacteria; it possesses genes for four polyP kinases (ppks), two polyP-dependent glucokinases (ppgks), and three phosphate transporters (pits).Furthermore, M. phosphovorus lacks the phaABC genes for PHA synthesis and the actP gene encoding an acetate/H(+) symporter, both of which play crucial roles in anaerobic PHA accumulation in proteobacterial PAOs.Thus, while the general features of M. phosphovorus regarding aerobic polyP accumulation are similar to those of proteobacterial PAOs, its anaerobic polyP use and PHA synthesis appear to be different.

View Article: PubMed Central - PubMed

Affiliation: Biological Resource Center, National Institute of Technology and Evaluation, 2-10-49 Nishihara, Tokyo 151-0066, Japan.

ABSTRACT
Polyphosphate accumulating organisms (PAOs) belong mostly to Proteobacteria and Actinobacteria and are quite divergent. Under aerobic conditions, they accumulate intracellular polyphosphate (polyP), while they typically synthesize polyhydroxyalkanoates (PHAs) under anaerobic conditions. Many ecological, physiological, and genomic analyses have been performed with proteobacterial PAOs, but few with actinobacterial PAOs. In this study, the whole genome sequence of an actinobacterial PAO, Microlunatus phosphovorus NM-1(T) (NBRC 101784(T)), was determined. The number of genes for polyP metabolism was greater in M. phosphovorus than in other actinobacteria; it possesses genes for four polyP kinases (ppks), two polyP-dependent glucokinases (ppgks), and three phosphate transporters (pits). In contrast, it harbours only a single ppx gene for exopolyphosphatase, although two copies of ppx are generally present in other actinobacteria. Furthermore, M. phosphovorus lacks the phaABC genes for PHA synthesis and the actP gene encoding an acetate/H(+) symporter, both of which play crucial roles in anaerobic PHA accumulation in proteobacterial PAOs. Thus, while the general features of M. phosphovorus regarding aerobic polyP accumulation are similar to those of proteobacterial PAOs, its anaerobic polyP use and PHA synthesis appear to be different.

Show MeSH
Related in: MedlinePlus