Peculiar citric acid cycle of hydrothermal vent chemolithoautotroph Hydrogenovibrio crunogenus, and insights into carbon metabolism by obligate autotrophs.

The genome sequence of the obligate chemolithoautotroph Hydrogenovibrio crunogenus paradoxically predicts a complete oxidative citric acid cycle (CAC). This prediction was tested by multiple approaches including whole cell carbon assimilation to verify obligate autotrophy, phylogenetic analysis of CAC enzyme sequences and enzyme assays. Hydrogenovibrio crunogenus did not assimilate any of the organic compounds provided (acetate, succinate, glucose, yeast extract, tryptone). Enzyme activities confirmed that its CAC is mostly uncoupled from the NADH pool. 2-Oxoglutarate:ferredoxin oxidoreductase activity is absent, though pyruvate:ferredoxin oxidoreductase is present, indicating that sequence-based predictions of substrate for this oxidoreductase were incorrect, and that H. crunogenus may have an incomplete CAC. Though the H. crunogenus CAC genes encode uncommon enzymes, the taxonomic distribution of their top matches suggests that they were not horizontally acquired. Comparison of H. crunogenus CAC genes to those present in other 'Proteobacteria' reveals that H. crunogenus and other obligate autotrophs lack the functional redundancy for the steps of the CAC typical for facultative autotrophs and heterotrophs, providing another possible mechanism for obligate autotrophy.

Trends in adrenalectomy rates, indications, and physician volume: A statewide analysis of 1816 adrenalectomies.

BACKGROUND: Adrenalectomy rates seem to be increasing in Florida, possibly due to increased availability of laparoscopic adrenalectomy, identification of incidentalomas, and access to care for minorities. We hypothesized that the rate of adrenalectomies in Florida increased from 1998-2005 while characteristics of patients, diagnoses, operations, and operating physicians changed over this period. METHODS: Prospectively-collected, mandatory-reported, hospital discharge data for all inpatient adrenalectomies undertaken in Florida from 1998-2005 were obtained along with Florida census and physician certification and education data. Characteristics of adrenalectomy patients, diagnoses, operations, and physicians were analyzed. RESULTS: 1816 adrenalectomies were available for analysis. Yearly rates of adrenalectomy nearly doubled from 1.20 to 2.26 per 100,000 Florida residents (P = .0024). Overall, patient characteristics such as demographics, indications and comorbidities did not change, whereas hospital charges increased and length-of-stay (LOS) significantly decreased (P = .0031 and P < .0001, respectively). There was a non-significant trend toward a yearly increase in physician volume and an inverse relationship between physician volume categories and mean LOS (P < .0001). CONCLUSIONS: The rate of adrenalectomies is increasing in Florida. This increase was not associated with distinct trends in patient characteristics, although a significant decrease in LOS was identified. As these trends continue and adrenalectomy is applied more liberally, indications for adrenalectomy may need to be re-evaluated.