Optic atrophy type 1 (OPA1, MIM 165500) is a dominantly inherited optic neuropathy occurring in 1 in 50,000 individuals that features progressive loss in visual acuity leading, in many cases, to legal blindness. Phenotypic variations and loss of retinal ganglion cells, as found in Leber hereditary optic neuropathy (LHON), have suggested possible mitochondrial impairment. The OPA1 gene has been localized to 3q28-q29 (refs 13-19). We describe here a nuclear gene, OPA1, that maps within the candidate region and encodes a dynamin-related protein localized to mitochondria. We found four different OPA1 mutations, including frameshift and missense mutations, to segregate with the disease, demonstrating a role for mitochondria in retinal ganglion cell pathophysiology.

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Regular surveys of heterotrophic microflora from seawater were conducted in the subantarctic (Kerguelen archipelago) and Antarctic (Terre Adélie area). Although a predominance of psychrophilic bacteria could be expected for such polar marine environments, there were no significant differences between results obtained after incubation at two different temperatures (4°C for 21 days or 18°C for 6 days). To investigate this further, four sets of bacterial strains were isolated from the subantarctic area (early fall, late fall, spring, and summer) and one set of Antarctic bacteria was isolated in summer. The growth rates of the 143 strains collected were determined at four different temperatures (4, 7, 20, and 30°C). The results clearly indicated that a large majority of the isolated bacteria must be considered psychrotrophic and not truly psychrophilic strains.