Biology subjects

Tsuruda, M.

Publications and source records attributed to Tsuruda, M..

3 recordsLinked to original sources

bioRxiv2026

Developmental Gfi1 Dynamics Define Hematopoietic Emergenceand Adult Hematopoietic Stem Cell Potency

Gfi1 regulates endothelial-to-hematopoietic transition (EHT) and hematopoietic stem cell (HSC) maintenance; however, its expression dynamics remain unclear. We generated a non-disruptive Gfi1-T2A-mScarlet reporter to track Gfi1 expression. At E10.5, reporter selectively marked EHT in the dorsal aorta, umbilical artery, and vitelline artery. At E9.5, mScarlet-positive endothelial cells were present in the umbilical and vitelline arteries but were scarce in the dorsal aorta, indicating vascular-bed-specific differences in hemogenic activation. Gfi1 was broadly expressed in fetal liver HSCs, while higher expression levels identified HSCs with enhanced multilineage reconstitution and preferential T-cell output. Although Gfi1 expression declined during fetal-to-adult maturation, a subset of adult bone marrow HSCs retained expression and exhibited superior repopulating and self-renewal capacity. Bulk and single-cell transcriptomic analyses linked this subset to dormant and fetal-associated programs, including imprinted genes. Reduced chromatin accessibility at a conserved Gfi1 +26.5kb putative enhancer correlated with developmental Gfi1 downregulation. Thus, Gfi1 dynamics define EHT onset and functionally distinct HSC stemness.

cell biology↗

bioRxiv2025

Island invasions by the non-native vinegar fly Drosophila suzukii and its parasitoid wasps

Understanding how island characteristics influence the establishment and impact of invasive species and their natural enemies could inform both island biogeography and biological control theory. We studied the occurrence and relative abundances of the globally invasive fruit fly, Drosophila suzukii, and its recently introduced larval parasitoids, Leptopilina japonica and Ganaspis kimorum, across islands with varying sizes and levels of human-mediated transport in the Gulf and San Juan Islands of British Columbia (Canada) and Washington State (USA). Across two years and 58 sites, we collected D. suzukii and its parasitoids from wild blackberry, Rubus armeniacus, fruit. We predicted that parasitoids were more likely to be present on larger islands with higher levels of human activity and higher D. suzukii densities, and that the less specialized parasitoid species (L. japonica) would be more likely to establish on islands. We detected D. suzukii across all islands, indicating widespread establishment of this invasive pest. In contrast, we observed parasitoids on fewer than half of the islands. Leptopilina japonica was the only parasitoid of D. suzukii detected on islands. Parasitoid presence was marginally positively associated with island area and host density, but not average annual vehicle-ferry traffic (an indicator of human-mediated propagule pressure). Parasitism levels were low throughout the study region and we did not observe lower relative abundances of D. suzukii on islands where parasitoids were present - in fact, the relative abundance of D. suzukii tended to be higher on islands where the parasitoid L. japonica was detected. These findings suggest that island characteristics, host density, and a consumers host specificity may be associated with early establishment of introduced consumers on islands, but that a consumers presence may not inevitably result in host population suppression, at least over the short term.

ecology↗

bioRxiv2021

Adventive larval parasitoids reconstruct their close association with spotted-wing drosophila in the invaded North American range

Two species of larval parasitoids of the globally invasive fruit pest, Drosophila suzukii (Diptera: Drosophilidae), Leptopilina japonica and Ganaspis brasiliensis (both Hymenoptera: Figitidae), were detected in British Columbia, Canada in 2019. Both are presumed to have been unintentionally introduced from Asia, however; the extent of their establishment across different habitats with diverse host plants used by D. suzukii was unclear. In addition, there was no knowledge of the temporal dynamics of parasitism of D. suzukii by these two parasitoids. We repeatedly sampled the fruits of known host plants of D. suzukii over the entire 2020 growing season in British Columbia. We documented the presence of L. japonica and G. brasiliensis and estimated the apparent percentage of D. suzukii parasitized. Across a large region of southwestern British Columbia, both L. japonica and G. brasiliensis were found to be very common across a variety of mostly unmanaged habitats over the entire course of the season (May-October) in the fruits of most host plants known to host D. suzukii larvae. The two parasitoids were responsible for more than 98% of D. suzukii larval parasitism and usually co-existed. Parasitism of D. suzukii was variable among hosts plants and sites (0-66% percent parasitism) and appeared to be time-structured. Our study demonstrates that the close association between the two larval parasitoids and D. suzukii that exists in Asia has evidently been reconstructed in North America, resulting in the highest parasitism levels of D. suzukii yet recorded outside of its area of origin.

ecology↗