The nitrogen-fixing symbiont of alfalfa, Sinorhizobium meliloti, is able to use myo-inositol as the sole carbon source. Putative inositol catabolism genes (iolA and iolRCDEB) have been identified in the S. meliloti genome based on their similarities with the Bacillus subtilis iol genes. In this study, functional mutational analysis revealed that the iolA and iolCDEB genes are required for growth not only with the myo-isomer but also for growth with scyllo-and D-chiro-inositol as the sole carbon source. An additional, hypothetical dehydrogenase of the IdhA/MocA/GFO family encoded by the smc01163 gene was found to be essential for growth with scyllo-inositol, whereas the idhA-encoded myo-inositol dehydrogenase was responsible for the oxidation of D-chiro-inositol. The putative regulatory iolR gene, located upstream of iolCDEB, encodes a repressor of the iol genes, negatively regulating the activity of the myo-and the scyllo-inositol dehydrogenases. Mutants with insertions in the iolA, smc01163, and individual iolRCDE genes could not compete against the wild type in a nodule occupancy assay on alfalfa plants. Thus, a functional inositol catabolic pathway and its proper regulation are important nutritional or signaling factors in the S. meliloti-alfalfa symbiosis.The sugar alcohol inositol, or cyclohexanehexol, occurs in several different stereoisomers, of which the myo-form (Fig. 1, compound 1) is the most abundant (1). myo-Inositol plays important structural and signaling roles in animal and plant cells (22). In the environment, myo-inositol mainly occurs in the phosphorylated form and is involved in the phosphate cycle of terrestrial and freshwater ecosystems (41). The stereoisomers D-chiro-and scylloinositol have recently attracted attention, because they have shown therapeutic potentials for diabetes and Alzheimer's disease, respectively (11, 21). Although there is only limited knowledge about the metabolism of D-chiro-and scyllo-inositol (25, 50), the catabolism of myo-inositol has been studied in a variety of microorganisms, including some members of the Firmicutes (17, 46, 51), Enterobacteriaceae (4,19,40), and Rhizobiaceae (16,29). The myo-inositol catabolic pathway and its regulation are best understood in the Gram-positive bacterium Bacillus subtilis. The B. subtilis iol genes are organized in a divergon comprising iolABCDEFGHIJ and iolRS (47-49). In the proposed inositol catabolic pathway, the myo-inositol dehydrogenase oxidizes myoinositol to its corresponding ketone 2-keto-myo-inositol (2KMI), which is then further catabolized by the actions of IolE, -D, -B, -C, -J, and -A (Fig. 1). The inducer of the inositol catabolic pathway in B. subtilis is the product of the IolC reaction, 2-deoxy-5-keto-D-gluconic acid 6-phosphate (DKGP; compound 6 in Fig. 1), which antagonizes the binding of the IolR repressor to the iol promoter region (51).Sinorhizobium meliloti, the nitrogen-fixing symbiont of alfalfa, can use myo-inositol as the sole carbon source (15). The idhA-encoded myo-inositol dehydrogenase had been s...

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Purpose of reviewThis review examines the delivery of rehabilitation care to cancer patients with relation to disease prognosis. This includes the evaluation when patients are referred for rehabilitation services and the effectiveness of rehabilitation interventions across the cancer continuum.Recent findingsAlthough prognosticating life expectancy is difficult, referrals for rehabilitation interventions appear to be affected by physician attitudes towards patients with advanced disease, in part because of misconceptions about the nature of rehabilitation for oncology patients. Rehabilitation may also be underutilized in long-term survivors with no evidence of disease. Despite this, our review found that rehabilitation in advanced disease, end-of-life, geriatric cancer patients, and in long-term survivors can be beneficial. There is a relative dearth in studies on rehabilitation interventions specifically at the end-of-life.SummaryCancer rehabilitation can be helpful to patients along the spectrum of cancer prognoses. Examining more accurate ways to prognosticate life expectancy, improving communication and education between oncologists and rehabilitation team members, and modifying survivorship plans to include patient education on functional changes over time may improve the delivery of rehabilitation care.

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