Biology subjects

Yoshioka, A.

Publications and source records attributed to Yoshioka, A..

3 recordsLinked to original sources

bioRxiv2023

Chemo-senolytic therapeutic potential against angiosarcoma

Angiosarcoma is an aggressive soft-tissue sarcoma with a poor prognosis. Chemotherapy for this cancer typically employs paclitaxel, one of the taxanes (genotoxic drugs), although it has a limited effect due to chemoresistance for prolonged treatment. Here we examine a new angiosarcoma treatment approach that combines chemotherapeutic and senolytic agents. We first find that the chemotherapeutic drugs, cisplatin and paclitaxel, efficiently induce cellular senescence of angiosarcoma cells. Subsequent treatment with a senolytic agent, ABT-263, eliminates senescent cells through the activation of the apoptotic pathway. In addition, expression analysis indicates that senescence-associated secretory phenotype (SASP) genes are activated in senescent angiosarcoma cells and that ABT-263 treatment eliminates senescent cells expressing genes in the type-I interferon (IFN-I) pathway. Moreover, we show that cisplatin treatment alone requires a high dose to remove angiosarcoma cells, whereas a lower dose of cisplatin is sufficient to induce senescence, followed by the elimination of senescent cells by senolytic treatment. This study sheds light on a potential therapeutic strategy against angiosarcoma by combining a relatively low dose of cisplatin with the ABT-263 senolytic agent, which can help ease the deleterious side effects of chemotherapy.

cancer biology↗

bioRxiv2023

Evolution of a large periplasmic disk in Campylobacterota flagella facilitated efficient motility alongside autoagglutination

Although the bacterial flagella of Escherichia coli and Salmonella enterica are distributed around the cell body, many bacteria instead place their flagella at their poles. This widespread form of flagellar motility is relatively poorly understood, but these polar flagellar motors invariably feature periplasmic disk structures of unknown function. The flagellar motor of Campylobacter jejuni features a 100 nm-wide periplasmic disk associated with scaffolding a wider ring of motor proteins to increase torque, but the size of this disk is excessive for a role solely in scaffolding motor proteins. Here we show that the basal disk in C. jejuni is a flange that braces the motor during disentanglement of the flagellar filament from interactions with the cell body and other filaments, interactions that are otherwise important for host colonization. Our results reveal an entanglement of co-dependencies in the evolution of flagellar motor structure and cell plan in the Campylobacterota (previously epsilonproteobacteria). Note that this manuscript has a sibling manuscript titled Molecular model of a bacterial flagellar motor in situ reveals a "parts-list" of protein adaptations to increase torque that describes a molecular model of the Campylobacter jejuni flagellar motor discussed here.

microbiology↗

bioRxiv2023

Distance sampling with vehicle-mounted cameras for the estimation of farmland bird abundance over a wide area.

Farmland bird populations are declining due to farmland abandonment and agricultural intensification. Effective conservation strategies require appropriate monitoring approaches, including efficient and scalable survey methods. In this study, we developed a large-scale monitoring method for herons and egrets (Ardeidae) using vehicle-mounted video cameras and distance sampling models that incorporate location uncertainty. The survey was conducted in and around the evacuation zone of the Fukushima Daiichi nuclear power plant accident. A total of 7,031 km of roadside video footage was recorded, covering 24.41 km{superscript 2} of farmland. Ardeidae were observed only outside the evacuation zone and were entirely absent within it. Predicted abundance differed greatly between areas inside (0.0279 {+/-} 0.0307/km{superscript 2}) and outside (4.57 {+/-} 5.36/km{superscript 2}) the evacuation zone. Incorporating location uncertainty into the distance sampling model had little effect on the estimates (4.57 {+/-} 5.36 vs. 4.51 {+/-} 5.29/km{superscript 2} with and without integrating location uncertainty, respectively). This suggests that our video-based roadside survey method is robust to location uncertainty in structured landscapes such as Japanese rice paddies. The accuracy may be attributed to the study system, where levees and roads divide paddy fields, limiting potential error in observer-target distances Our method can be applied to other open habitats, such as natural grasslands and wetlands, especially in areas lacking artificial markers, by incorporating measurement uncertainty into the model. This combination of roadside surveys with vehicle-mounted cameras and distance sampling provides a practical and transferable approach for monitoring large-bodied species in open landscapes, enhancing both the efficiency and spatial coverage of biodiversity assessments. HighlightsBroad-scale farmland abandonment following the Fukushima Daiichi nuclear power plant accident led to sharp declines in large farmland bird abundance. Efficient large-scale roadside surveys were conducted using vehicle-mounted video cameras. Ardeidae abundance was estimated using distance sampling models that incorporated location uncertainty. The survey method is robust and applicable to open habitats such as farmlands, grasslands, and wetlands.

ecology↗