Biology subjects

Wu, Y.-T.

Publications and source records attributed to Wu, Y.-T..

4 recordsLinked to original sources

bioRxiv2024

Phoretic mites as benign passengers: no influence on mate choice in the burying beetle Nicrophorus nepalensis

Mate choice is a fundamental aspect of sexual selection where the chooser chooses a courter by assessing a variety of traits that communicate potential fitness. However, the influence of interspecific interactions, such as symbiosis, on mate choice remains underexplored. We addressed this shortcoming with experiments on burying beetle Nicrophorus nepalensis and their interactions with phoretic mites Poecilochirus carabi. The mites can act either as mutualists or parasites depending on the presence of competitors and mite densities, thus potentially influencing mate choice. In a laboratory experiment, we presented female N. nepalensis with a range of natural mite densities: 0, 5, 10, or 20, with males carrying either 0 or 10 mites in an olfactory-based mate choice assay. Subsequently we allowed females to breed with their chosen male and all their mites before evaluating the fitness effects of the varying mite densities. We found that females across all mite densities had no preference for males with or without mites. In line with this, the mite densities had no effect on the brood size or the averaged larva mass. However, the mite densities per breeding cohort did positively affect the number of mite offspring. Our results suggest that mites act as benign passengers, not directly affecting mate choice or fitness.

ecology↗

bioRxiv2024

Human activity, not environmental factors, drives Scedosporium and Lomentospora distribution in Taiwan

Scedosporium and Lomentospora species are emerging fungal pathogens capable of causing severe infections in both immunocompetent and immunocompromised individuals. Previous environmental surveys have suggested potential associations between these fungi and various soil chemical parameters, though the relative influence of human activity versus environmental factors has not been systematically evaluated. Here, we conducted a comprehensive survey of 406 soil samples from 132 locations across Taiwan, analyzing fungal abundance alongside soil physicochemical parameters and the Human Footprint Index (HFI). We recovered 236 fungal isolates comprising 10 species, with S. boydii (32.2%), S. apiospermum (30.9%), and S. dehoogii (14.4%) being the most prevalent. The highest fungal burdens were observed in urban environments (up to 1293 CFU/g), particularly in public spaces and healthcare facilities. Statistical analysis revealed a significant positive correlation between fungal abundance and HFI (r = 0.125, p = 0.013), while soil chemical parameters including nitrogen, carbon, pH, electrical conductivity, and various base cations showed no significant associations despite their wide ranges. These findings indicate that anthropogenic disturbance of environments, rather than soil chemistry, is the primary driver of Scedosporium and Lomentospora distribution in Taiwan. This understanding holds important implications for predicting infection risks and developing targeted public health strategies, particularly in rapidly urbanizing regions. Future studies incorporating more specific indicators of human impact may further elucidate the mechanisms underlying these distribution patterns. Lay AbstractWe found that human activities, rather than soil properties, determine where Scedosporium/Lomentospora fungi distribute in Taiwan. These fungi are more abundant in urban areas than less-human-disturbed environments, suggesting increased infection risks in densely populated regions.

ecology↗

bioRxiv2024

Genome diversification of symbiotic fungi in beetle-fungus mutualistic symbiosis

Ambrosia beetles and their fungal symbionts represent a widespread and diverse insect-fungus mutualism. This study investigates the genomic adaptations associated with the evolution of the ambrosia lifestyle across multiple fungal lineages. We performed comparative genomic analyses on 70 fungal genomes from four families (Irpicaceae, Ceratocystidaceae, Nectriaceae, and Ophiostomataceae), including 24 ambrosia and 34 non-ambrosia lineages. Our phylogenomic analyses reveal multiple independent colonization of insect vectors by the fungi, spanning from the mid-Cretaceous (114.6 Ma) to the early Quaternary (1.9 Ma). Contrary to expectations for obligate symbionts, ambrosia fungi showed no significant genome-wide reductions in size, gene count, or secreted protein repertoire compared to their non-symbiotic relatives. Instead, we observed conservation of most assessed genomic features; where genome traits differ between free-living relatives and ambrosia fungi, the changes are lineage-specific, not convergent. Key findings include lineage-specific expansions in carbohydrate-active enzyme families (AA4 in Nectriaceae, CE4 in Ophiostomataceae, and GH3 in Ophiostomataceae and Ceratocystidaceae), suggesting potential enhancement or loss of lignin modification, hemicellulose deacetylation, and cellulose degradation in different ambrosia lineages. Repeat-Induced Point mutation analysis revealed family-specific patterns rather than lifestyle-associated differences. These results highlight the diverse genomic strategies employed by ambrosia fungi, demonstrating that symbiont evolution can proceed through refined, lineage-specific changes rather than genome-wide, or convergent alterations. Unlike other insect-associated fungi, ambrosia fungi do not seem to be domesticated crops, but rather free-living fungi which co-opted wood boring beetles as vectors via subtle, lineage-specific adaptations.

evolutionary biology↗

bioRxiv2022

Pregnenolone reorganizes cytoskeleton to promote neuron development via CLIP1

Pregnenolone (P5) is a neurosteroid produced in the brain. It improves cognitive function and protects against cannabis intoxication as well as spinal cord injury. P5 activates CLIP1, which helps microtubule polymerization at its growing end; however, the significance of P5 activation of CLIP1 in the brain is still unknown. Here we examined the roles of P5 in cultured neurons and in zebrafish cerebellum. We show that P5 promotes neurite outgrowth and facilitates axon development of cultured cerebellar granule neurons. P5 also changes the morphology of axon growth cone and promotes dynamic microtubule invasion into the distal part of filopodia at the growth cone. We have used CRISPR to disrupt clip1a in zebrafish, disrupting the ability of P5 to change microtubule dynamics and growth cone morphology, as well as to reorganize cytoskeleton. In vivo, P5 accelerated cerebellum development in WT but not clip1a mutant zebrafish, and expression of exogenous CLIP1 in clip1a mutant promoted cerebellum development in response to P5. Thus, we have delineated the pathway by which P5 promotes cerebellum development by activating CLIP1 to promote microtubule dynamics leading to increased microtubule penetration into the growth cone and accelerated neurite outgrowth. This study reveals the mechanism by which P5 and CLIP1 function to promote neural development. Significance Statement1. We have elucidated the mechanism of pregnenolone (P5) actionP5 enhances brain functions, but its mode of action was unclear. Here we show that P5 activates CLIP1 to promote microtubule dynamics at the growth cone and to accelerate neural development. 2. We have generated a zebrafish model of CLIP1 deficiencyCLIP1 deficiency causes intellectual disability and defective neural development. Our zebrafish model can be used to study mechanisms related to this disease and other microtubule defects. 3. We point to therapeutic intervention of neurological diseases using P5P5 is beneficial to the brain. We elucidate the mechanism of P5 action, thus accelerate the development of therapeutics using P5 and its derivatives.

neuroscience↗