To assess the extent of genotypic and phenotypic diversity within species of purple nonsulfur bacteria found in aquatic sediments, a total of 128 strains were directly isolated from agar plates that had been inoculated with sediment samples from Haren and De Biesbosch in The Netherlands. All isolates were initially characterized by BOX-PCR genomic DNA fingerprinting, and 60 distinct genotypes were identified. Analyses of 16S rRNA gene sequences of representatives of each genotype showed that five and eight different phylotypes of purple nonsulfur bacteria were obtained from the Haren and De Biesbosch sites, respectively. At the Haren site, 80.5% of the clones were Rhodopseudomonas palustris, whereas Rhodoferax fermentans and Rhodopseudomonas palustris were numerically dominant at the De Biesbosch site and constituted 45.9 and 34.4% of the isolates obtained, respectively. BOX-PCR genomic fingerprints showed that there was a high level of genotypic diversity within each of these species. The genomic fingerprints of Rhodopseudomonas palustris isolates were significantly different for isolates from the two sampling sites, suggesting that certain strains may be endemic to each sampling site. Not all Rhodopseudomonas palustris isolates could degrade benzoate, a feature that has previously been thought to be characteristic of the species. There were differences in the BOX-PCR genomic fingerprints and restriction fragment length polymorphisms of benzoate-coenzyme A ligase genes and form I and form II ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) genes between benzoate-degrading and non-benzoate-degrading genotypes. The ability to distinguish these two Rhodopseudomonas palustris groups based on multiple genetic differences may reflect an incipient speciation event resulting from adaptive evolution to local environmental conditions.Many species of bacteria in the environment, particularly in soil, are composed of genetically distinct and diverse clones (5,13,21,22,27,28,52). This diversification has resulted from evolutionary processes (4,28,30,35,41) that occur during adaptive evolution to local conditions in heterogeneous environments that contain a range of ecologically distinct habitats (28). This is in contrast to what is observed with many pathogenic and commensal bacterial species, which often exhibit clonal population structures that are correlated to differences in host environmental specificity and geographic differences (1,7,12,27,29,40,43,51).There have been numerous studies to assess the genetic diversity in closely related bacteria by PCR-based genome analysis techniques, including repetitive-sequence-based PCR (rep-PCR), amplified fragment length polymorphism, and random amplified polymorphic DNA techniques. The species studied include human-, animal-, and plant-associated bacteria, such as Escherichia coli (7,17), Helicobacter pylori (2), Bradyrhizobium sp. (47, 48), Pseudomonas syringae (24, 25), Rhizobium sp. (6, 23), and several species of the genus Xanthomonas (32,33). These studies were ai...

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ObjectiveTo determine the vision-related quality of life (VR-QOL) after surgery for macula-off rhegmatogenous retinal detachment (RRD) in relation to visual acuity, contrast acuity, and color vision.MethodsIn a prospective observational study, we included 55 patients with a macula-off RRD. Best corrected visual acuity (BCVA), color vision (saturated and desaturated color confusion indices (CCI)) and contrast acuity were measured at 12 months postoperatively in both the RRD eye and the fellow control eye, and the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) was filled out.ResultsOperated and fellow control eyes differed significantly in mean LogMAR BCVA (P<0.0001), median Log contrast acuity (P<0.0001), saturated CCI (P = 0.009), and desaturated CCI (P = 0.016). Significant correlations were observed between the NEI VFQ-25 overall composite score and postoperative LogMAR BCVA (R = −0.551, P<0.0001), contrast acuity (R = 0.472, P<0.0001), saturated CCI (R = −0.315, P = 0.023), and desaturated CCI (R = −0.283, P = 0.044).ConclusionsA lower VR-QOL was highly correlated to a worse postoperative BCVA and contrast acuity and to a lesser extent to color vision disturbances.

No author has a financial or proprietary interest in any material or method mentioned.