Reinstatement of the fission yeast species Schizosaccharomyces versatilis Wickerham et Duprat, a sibling species of Schizosaccharomyces japonicus.

Schizosaccharomyces japonicus Yukawa et Maki (1931) and Schizosaccharomyces versatilis Wickerham et Duprat (1945) have been treated as varieties of S. japonicus or as conspecific, based on various approaches including mating trials and nDNA/nDNA optical reassociation studies. However, the type strains of S. japonicus and S. versatilis differ by five substitutions (99.15% identity) and one 1-bp indel in the sequences of the D1/D2 domain of the 26S rRNA gene, and 23 substitutions (96.3% identity) and 31-bp indels in the sequences of internal transcribed spacer (ITS) of rRNA, suggesting that they may not be conspecific. To reassess their taxonomic status, we conducted mating trials and whole-genome analyses. Mating trials using the type strains showed a strong but incomplete prezygotic sterility barrier, yielding interspecies mating products at two orders of magnitude lower efficiency than intraspecies matings. These mating products, which were exclusively allodiploid hybrids, were unable to undergo the haplontic life cycle of the parents. We generated chromosome-level gap-less genome assemblies for both type strains. Whole genome sequences yielded an average nucleotide identity (ANI) of 86.4%, indicating clear separation of S. japonicus and S. versatilis. Based on these findings, we propose the reinstatement of S. versatilis as a distinct species (holotype strain: CBS 103T and ex-types: NRRL Y-1026, NBRC 1607, ATCC 9987, PYCC 7100; Mycobank no.: 847838).

Linking the relationship between dietary folic acid intake and risk of osteoporosis among middle-aged and older people: A nationwide population-based study.

Among middle-aged and older people, balanced and nutritious diets are the foundation for maintaining bone health and preventing osteoporosis. This study is aimed at investigating the link between dietary folic acid intake and the risk of osteoporosis among middle-aged and older people. A total of 20,686 people from the National Health and Nutritional Examination Survey (NHANES) 2007-2010 are screened and included, and 5312 people aged ≥45 years with integral data are ultimately enrolled in evaluation. Demographics and dietary intake-related data are gathered and analyzed, and the odds ratio (OR) and 95% confidence interval (CI) of each tertile category of dietary folic acid intake and each unit increase in folic acid are assessed via multivariate logistic regression models. On this basis, the receiver operating characteristic (ROC) curve is used to identify the optimal cutoff value of dietary folic acid intake for indicating the risk of osteoporosis. Of 5312 people with a mean age of 62.4 ± 11.0 years old, a total of 513 people with osteoporosis are screened, and the dietary folic acid intake amount of the osteoporosis group is significantly lower than that of the non-osteoporosis group (p < .001). The lowest tertile category is then used to act as a reference category, and a higher dietary folic acid intake amount is observed to be positively related to lower odds for risk of osteoporosis. This trend is also not changed in adjustments for combinations of different covariates (p all < .05). Based on this, a dietary folic acid intake of 475.5 µg/day is identified as an optimal cutoff value for revealing osteoporosis. Collectively, this nationwide population-based study reveals that a higher daily dietary folic acid intake has potential protective effects on osteoporosis in middle-aged and older people.