Biology subjects

Tsutaya, T.

Publications and source records attributed to Tsutaya, T..

3 recordsLinked to original sources

bioRxiv2025

Carbon and nitrogen stable isotopic profiling of chimpanzees and other primate hairs in Kalinzu Forest Reserve, Uganda

Stable isotope analysis is a widely used tool in primate ecology for investigating diet and environment, with numerous studies focusing on chimpanzees. However, few studies have explored the dietary niche of chimpanzees in comparison to other primates or examined intra-individual dietary variability. This limitation hinders the understanding of the comparability of isotopic data with the wealth of behavioral observational data in primate ecology. In this study, we report the carbon and nitrogen stable isotope ratios of hairs from wild chimpanzees and four other primate species in the Kalinzu Forest Reserve, Uganda. Bulk analysis revealed that both plant foods and chimpanzees in Kalinzu exhibited lower carbon isotope ratios than expected for the regions rainfall. Additionally, preliminary compound-specific nitrogen isotope analysis of amino acids was conducted, revealing that chimpanzees in Kalinzu have a lower degree of faunivory than the sympatric Cercopithecus primates. Furthermore, ultra-fine sectioning of a hair sample was conducted to investigate dietary variation over daily to weekly timescales. In one adult male chimpanzee, carbon and nitrogen isotope ratios fluctuated by more than 1{per thousand} within approximately 10 days. These findings highlight the importance of recognizing uncontrolled ecological variability and hidden intra-individual dietary changes when interpreting stable isotope data in relation to behavior and environmental traits.

ecology↗

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↗

bioRxiv2023

Palaeoproteomic investigation of an ancient human skeleton with abnormal deposition of dental calculus

Detailed investigation of extremely severe pathological conditions in ancient human skeletons is important as it could shed light on the breadth of potential interactions between humans and disease etiologies in the past. Here, we applied palaeoproteomics to investigate an ancient human skeletal individual with severe oral pathology, focusing our research on bacterial pathogenic factors and host defense response. This female skeleton, from the Okhotsk period (i.e., 5th-13th century) of Northern Japan, poses relevant amounts of abnormal dental calculus deposition and exhibits oral dysfunction due to severe periodontal disease. A shotgun mass-spectrometry analysis identified 81 human proteins and 15 bacterial proteins from the calculus of the subject. We identified two pathogenic or bioinvasive proteins originating from two of the three "red complex" bacteria, the core species associated with severe periodontal disease in modern humans, as well as two additional bioinvasive proteins of periodontal-associated bacteria. Moreover, we discovered defense response system-associated human proteins, although their proportion was mostly similar to those reported in ancient and modern human individuals with lower calculus deposition. These results suggest that the bacterial etiology was similar and the host defense response was not necessarily more intense in ancient individuals with significant amounts of abnormal dental calculus deposition.

evolutionary biology↗