Biology subjects

Aruga, N.

Publications and source records attributed to Aruga, N..

4 recordsLinked to original sources

bioRxiv2026

Dual targeting of astrocytic and endothelial GLUT1 enables functional rescue in GLUT1 deficiency syndrome

Glucose transporter 1 deficiency syndrome (GLUT1-DS) is a severe neurometabolic disorder caused by impaired brain glucose transport. Because GLUT1 has been classically viewed as predominantly localized to blood-brain barrier endothelial cells, gene therapy strategies have largely focused on endothelial GLUT1 restoration. However, whether this endothelial-centered model fully explains disease pathogenesis and therapeutic rescue has remained unclear. Using enhanced detection in mouse brain and human postmortem tissue, we show that GLUT1 is broadly expressed in astrocytes as well as endothelial cells, extending beyond perivascular endfeet into astrocytic somata and processes. Conditional Glut1 haploinsufficiency in either astrocytes or endothelial cells reproduced GLUT1-DS-like reductions in cerebrospinal fluid glucose availability and brain parenchymal glucose responses, together with cognitive and motor impairments. To determine the therapeutic consequence of this revised cellular model, we used complementary endothelial- and astrocyte-directed AAV delivery to restore GLUT1 in systemic Glut1 haploinsufficient mice. Single-compartment restoration produced partial benefit, whereas dual-compartment restoration more robustly improved cerebrospinal fluid glucose availability and cognitive function. These findings indicate that endothelial GLUT1 restoration alone is insufficient for robust rescue and redefine GLUT1-DS as a multicellular disorder of the neurovascular unit.

neuroscience↗

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↗

bioRxiv2024

Mouth-attaching copepod Salmincola markewitschi reduces the body condition and growth of juvenile salmonid Salvelinus leucomaenis by decreasing host feeding activity: evidence from parasite removal experiment

Ectoparasitic copepods in the genus Salmincola Wilson, 1915 are considered harmful to host salmonids, yet experimental studies on whether and how these copepods affect hosts are critically limited. We evaluated the effects of the mouth-attaching Salmincola markewitschi Shedko and Shedko, 2002 on juvenile white-spotted charr Salvelinus leucomaenis (Pallas, 1814) using a parasite removal experiment where all individuals were artificially infected, and then parasites were removed in one group (i.e., treatment), while the copepods were left in another group (i.e., control). We hypothesized that the copepods reduce host feeding, thereby reducing host body condition and growth. The alternative hypothesis is that parasites do not change host feeding, or even increase because of the compensation for the negative effect. In this case, host condition and growth would not be reduced. The control group (parasite remained) had lower food consumption, body condition, and growth compared to the treatment (parasite removed). Thus, S. markewitschi negatively affected hosts by reducing host feeding, and no behavioral compensation was observed. It remains unknown, however, whether reduced feeding was due to impaired swallowing or physiological stresses caused by infections. Further experiments on gill- and body-surface-attaching Salmincola species could provide deeper insights into how these parasites influence host health.

ecology↗

bioRxiv2023

Hot spots in a cold river synchronize temporarily separated salmon runs in their offsprings development

The identification of thermal heterogeneity in the environment and its inclusion in adaptive strategies are key to habitat management of cold-water fish, including salmonid species. This study tested the hypothesis that upwelling of groundwater (GW) from a tributary catchment through a relatively deep aquifer (tributary GW) affects salmon redds selection in an urbanized gravel-bed river, and that the spawning preference of such areas depends on the seasonal context. The field study was conducted between 2001 and 2015 in an approximately 6-km long segment of the Toyohira River, Northern Japan. Chum salmon redds distribution data over 15 years (2001-2015) were combined with spatial distribution data of hyporheic water affected by tributary GW in the riverbed to examine seasonally variable redds site selection in relation to the presence of unique GW. Furthermore, models that predicted the hyporheic water thermal regime were coupled with redds count data to estimate the approximate timing of fry emergence from the riverbed. The redds site selection was seasonally variable, with a higher dependence on tributary-GW-affected areas with a decrease in water temperature. The time until fry emergence from spawning was shortened when the tributary-GW area was chosen during the cold winter. Overall, the present study identified hotspots for salmon spawning redds in winter with a disproportionately high level of site selection because of their warmer temperature compared to surface river water in winter. Thermally diverse spawning habitats allow the diversification of spawner strains in synchronized descents to the sea. Signs of tributary-GW pollution was suggested, and thus the conservation of the groundwater pathway and its sources, followed by improvements in quality, can be beneficial to the Chum salmon populations in the Toyohira River.

ecology↗