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This study aimed to examine whether social isolation (isolation) defined as having less contact than once a week with anyone outside the household was associated with medical and long-term care utilization. We conducted a two-wave questionnaire survey among city residents aged over 65 years (Wave 1 in 2008 and Wave 2 in 2010) in Wako city, Japan. From health insurance claim data and long-term care data from 2008 to 2011, the present cohort study extracted data receiving medical and long-term care and the related expenses in the three-year period. Using a two-part model to identify the association of isolation with receiving medical and long-term care and the related expenses, we analyzed 1,520 older adults. Approximately 29.6% of the participants were isolated. Using logistic regression-adjusted covariates (sex, age, educational level, resident status, household income, instrumental activities of daily living, depression symptoms, and the prevalence of cardiovascular disease, liver disease or other diseases), isolation was negatively associated with receiving medical outpatient care (adjusted odds ratio: 0.407, 95% confidence interval[95%CI]: 0.235 to 0.703). Moreover, in the generalized linear model for data with a gamma distribution with a log-link function, isolation was negatively associated with outpatient care expenses (adjusted risk ratio: 0.833, 95%CI: 0.747 to 0.928). There were no significant associations of isolation with inpatient care and long-term care and the related expenses. The negative associations of isolation with receiving outpatient care and the related expenses among older adults may demonstrate that those with isolation do not receive the medical outpatient care they required.

Ferns are the only major lineage of vascular plants not represented by a sequenced nuclear genome. This lack of genome sequence information significantly impedes our ability to understand and reconstruct genome evolution not only in ferns, but across all land plants. Azolla and Ceratopteris are ideal and complementary candidates to be the first ferns to have their nuclear genomes sequenced. They differ dramatically in genome size, life history, and habit, and thus represent the immense diversity of extant ferns. Together, this pair of genomes will facilitate myriad large-scale comparative analyses across ferns and all land plants. Here we review the unique biological characteristics of ferns and describe a number of outstanding questions in plant biology that will benefit from the addition of ferns to the set of taxa with sequenced nuclear genomes. We explain why the fern clade is pivotal for understanding genome evolution across land plants, and we provide a rationale for how knowledge of fern genomes will enable progress in research beyond the ferns themselves.

Vascular plants appeared ~410 million years ago, then diverged into several lineages of which only two survive: the euphyllophytes (ferns and seed plants) and the lycophytes. We report here the genome sequence of the lycophyte Selaginella moellendorffii (Selaginella), the first nonseed vascular plant genome reported. By comparing gene content in evolutionarily diverse taxa, we found that the transition from a gametophyte- to a sporophyte-dominated life cycle required far fewer new genes than the transition from a nonseed vascular to a flowering plant, whereas secondary metabolic genes expanded extensively and in parallel in the lycophyte and angiosperm lineages. Selaginella differs in posttranscriptional gene regulation, including small RNA regulation of repetitive elements, an absence of the trans-acting small interfering RNA pathway, and extensive RNA editing of organellar genes.

We determined the complete nucleotide sequence of the chloroplast genome of the leptosporangiate fern, Adiantum capillus-veneris L. (Pteridaceae). The circular genome is 150,568 bp, with a large single-copy region (LSC) of 82,282 bp, a small-single copy region (SSC) of 21,392 bp and inverted repeats (IR) of 23,447 bp each. We compared the sequence to other published chloroplast genomes to infer the location of putative genes. When the IR is considered only once, we assigned 118 genes, of which 85 encode proteins, 29 encode tRNAs and 4 encode rRNAs. Four protein-coding genes, all four rRNA genes and six tRNA genes occur in the IR. Most (57) putative protein-coding genes appear to start with an ATG codon, but we also detected five other possible start codons, some of which suggest tRNA editing. We also found 26 apparent stop codons in 18 putative genes, also suggestive of RNA editing. We found all but one of the tRNA genes necessary to encode the complete repertoire required for translation. The missing trnK gene appears to have been disrupted by a large inversion, relative to other published chloroplast genomes. We detected several structural rearrangements that may provide useful information for phylogenetic studies.