Isolation and characterization of microsatellite loci for the endangered wetland plant Adenophora palustris (Campanulaceae).

PREMISE OF THE STUDY: Adenophora palustris (Campanulaceae) is an endangered wetland plant species in Japan. Although it is widely distributed in East Asia, only six extant populations are known in Japan, with fewer than 1000 individuals in total. We developed 15 microsatellite markers for this species and confirmed their utility for the closely related species A. triphylla var. japonica. METHODS AND RESULTS: Ten polymorphic loci were characterized for genetic variation within three populations of A. palustris. The number of alleles per locus ranged from four to 15, with an average of 9.3; the expected heterozygosity ranged from 0.48 to 0.89, with an average of 0.74. Nine loci were successfully amplified in A. triphylla var. japonica, and three of these loci showed polymorphism. CONCLUSIONS: These markers are useful for investigating genetic diversity and gene flow within and among remnant populations of A. palustris in Japan, and the results will provide crucial information for conservation.

Evaluation of the Environmental DNA Method for Estimating Distribution and Biomass of Submerged Aquatic Plants.

The environmental DNA (eDNA) method has increasingly been recognized as a powerful tool for monitoring aquatic animal species; however, its application for monitoring aquatic plants is limited. To evaluate eDNA analysis for estimating the distribution of aquatic plants, we compared its estimated distributions with eDNA analysis, visual observation, and past distribution records for the submerged species Hydrilla verticillata. Moreover, we conducted aquarium experiments using H. verticillata and Egeria densa and analyzed the relationships between eDNA concentrations and plant biomass to investigate the potential for biomass estimation. The occurrences estimated by eDNA analysis closely corresponded to past distribution records, and eDNA detections were more frequent than visual observations, indicating that the method is potentially more sensitive. The results of the aquarium experiments showed a positive relationship between plant biomass and eDNA concentration; however, the relationship was not always significant. The eDNA concentration peaked within three days of the start of the experiment in most cases, suggesting that plants do not release constant amounts of DNA. These results showed that eDNA analysis can be used for distribution surveys, and has the potential to estimate the biomass of aquatic plants.

Microsatellite markers for Nuphar japonica (Nymphaeaceae), an aquatic plant in the agricultural ecosystem of Japan.

PREMISE OF THE STUDY: Nuphar species (Nymphaeaceae) are representative aquatic plants in irrigation ponds in Japanese agricultural ecosystems. We developed 15 polymorphic microsatellite markers for N. japonica and confirmed their utility for its close relatives N. oguraensis var. akiensis and N. ×saijoensis, which originated from natural hybridization between N. japonica and N. oguraensis. METHODS AND RESULTS: Genetic variation was characterized in 15 polymorphic loci in three populations of N. japonica. The average number of alleles per locus was 3.47 (range = 2-9; n = 32), and the average expected heterozygosity per locus was 0.84 (range = 0.5-1.0); 11 loci were amplified in N. oguraensis var. akiensis and 15 in N. ×saijoensis. CONCLUSIONS: The polymorphic microsatellite markers developed in this study will be useful for investigating the levels of genetic diversity within remnant populations of Nuphar taxa and could provide a valuable tool for conservation genetics of these taxa.

SPDL-1 functions as a kinetochore receptor for MDF-1 in Caenorhabditis elegans.

The spindle assembly checkpoint (SAC) ensures faithful chromosome segregation by delaying anaphase onset until all sister kinetochores are attached to bipolar spindles. An RNA interference screen for synthetic genetic interactors with a conserved SAC gene, san-1/MAD3, identified spdl-1, a Caenorhabditis elegans homologue of Spindly. SPDL-1 protein localizes to the kinetochore from prometaphase to metaphase, and this depends on KNL-1, a highly conserved kinetochore protein, and CZW-1/ZW10, a component of the ROD-ZW10-ZWILCH complex. In two-cell-stage embryos harboring abnormal monopolar spindles, SPDL-1 is required to induce the SAC-dependent mitotic delay and localizes the SAC protein MDF-1/MAD1 to the kinetochore facing away from the spindle pole. In addition, SPDL-1 coimmunoprecipitates with MDF-1/MAD1 in vivo. These results suggest that SPDL-1 functions in a kinetochore receptor of MDF-1/MAD1 to induce SAC function.

Spindle assembly checkpoint gene mdf-1 regulates germ cell proliferation in response to nutrition signals in C. elegans.

When newly hatched Caenorhabditis elegans larvae are starved, their primordial germ cells (PGCs) arrest in the post-S phase. This starvation-induced PGC arrest is mediated by the DAF-18/PTEN-AKT-1/PKB nutrient-sensing pathway. Here, we report that the conserved spindle assembly checkpoint (SAC) component MDF-1/MAD1 is required for the PGC arrest. We identified 2 Akt kinase phosphorylation sites on MDF-1. Expression of a non-phosphorylatable mutant MDF-1 partially suppressed the defect in the starvation-induced PGC arrest in L1 larvae lacking DAF-18, suggesting that MDF-1 regulates germ cell proliferation as a downstream target of AKT-1, thereby demonstrating a functional link between cell-cycle regulation by the SAC components and nutrient sensing by DAF-18-AKT-1 during post-embryonic development. The phosphorylation status of MDF-1 affects its binding to another SAC component, MDF-2/MAD2. The loss of MDF-2 or another SAC component also caused inappropriate germ cell proliferation, but the defect was less severe than that caused by mdf-1 hemizygosity, suggesting that MDF-1 causes the PGC arrest by two mechanisms, one involving MDF-2 and another that is independent of other SAC components.

An analysis of the length of stay and effectiveness of treatment for hip fracture patients in Japan: evaluation of the 2002 Revision of the Medical Service Fee Schedule.

The length of hospital stay and effectiveness of medical treatment are analyzed using data of patients hospitalized due to hip fractures of four hospitals in Japan. The influence of the Revision of the Medical Service Fee Schedule in April, 2002, is evaluated, and factors which may have affected the length of stay and effectiveness of treatment (walking ability upon departure from the hospital) are also analyzed by a newly developed simultaneous equation model.

A new ferrochelatase mutation combined with low expression alleles in a Japanese patient with erythropoietic protoporphyria.

We investigated the molecular defect of the ferrochelatase gene in a Japanese patient with erythropoietic protoporphyria (EPP), and identified a novel 16 base pair (574-589) deletion within exon 5. This deletion resulted in a frame-shift mutation and created a premature stop codon at amino acid position 198. The same molecular defect was also identified in his mother and a brother who had symptomatic EPP, but not in his father who was asymptomatic. The subjects with EPP were homozygous for the low expression haplotype, while his father was heterozygous for this haplotype. These results indicate that the combination of a 16 base pair deletion and low expression of the wild-type allelic variant is responsible for EPP in this pedigree.