Biology subjects

Kumaki, T.

Publications and source records attributed to Kumaki, T..

3 recordsLinked to original sources

bioRxiv2025

From bones to sediments: ancient human DNA from open-air archaeological sites

Ancient human bones degrade and sometimes disappear, especially in regions with acidic soils, making it difficult to obtain genetic information from past populations. To explore alternative sources, we analyzed ancient DNA from sediment samples collected from a burial site and a settlement site in Japan, both dating to around 1000 years ago. We found that ancient human mitochondrial DNA was obtained from sediments surrounding bones, particularly close to rib bones, while human DNA was rarely detected in the settlement site sediments. Furthermore, the mitochondrial haplogroups identified in the sediments were identical to those from human bones, confirming the reliability of this approach. Our findings suggest that genetic information about past human populations can be directly obtained from archaeological sediments in open-air sites. This method also provides a non-destructive alternative to bones and teeth, expanding possibilities for ancient DNA research in regions where skeletal remains are poorly preserved.

molecular biology↗

bioRxiv2024

Enhanced anti-tumor effects through continuous administration of engineered CAR-macrophages derived from pluripotent stem cell-derived myeloid celllines.

Even after chimeric antigen receptor (CAR)-based immunotherapy has dramatically changed therapeutic approaches for malignancies, balancing therapeutic efficacy with labor and financial cost remains a major problem for immunotherapy. Current study developed a cost-effective and enhanced approach to chimeric antigen receptor (CAR)-macrophage therapy for cancer and demonstrated its therapeutic effects by repeated administration of anti-HER2 CAR macrophages generated from human pluripotent stem cell (PSC)-derived immortalized myeloid cell lines (ML). These ML-derived CAR macrophages (CAR-ML-MPs) exhibit potent antigen-specific killing activity against HER2-expressing tumor cells by phagocytosis in vitro and effectively inhibit tumor progression in vivo, which is enhanced by repeated administration. CAR-ML-MPs provide a promising off-the-shelf cellular resource for tumor adoptive cell immunotherapy, solving the cost and time problems associated with conventional CAR-based immunotherapy.

bioengineering↗

bioRxiv2018

Extreme genetic signatures of local adaptation during plant colonization

Colonization of new habitats is expected to require genetic adaptations to overcome environmental challenges. Here we use full genome re-sequencing and extensive common garden experiments to investigate demographic and selective processes associated with the recent colonization of Japan by Lotus japonicus. We carefully track the colonization process where L. japonicus gradually spread from subtropical conditions to much colder climates in northern Japan. We characterize the loss of diversity during this process and identify genomic regions with extreme genetic differentiation. Next, we perform population structure-corrected association mapping of phenotypic traits measured in a common garden and discover a number of genome-wide significant associations. Contrasting these analyses, we find that there is a strong concordance between phenotypic variation and extreme differentiation for overwintering and flowering time traits. Our results provide evidence that these traits were direct targets of selection by local adaptation during the colonization process and point to associated candidate genes.

evolutionary biology↗