Biology subjects

Oswald, J.

Publications and source records attributed to Oswald, J..

3 recordsLinked to original sources

bioRxiv2025

A genetic model for development, physiology and behavior of zebrafish larvae devoid of catecholamines

Dopamine and noradrenaline have conserved roles in control of physiology and behaviors of vertebrates. However, vertebrate genetic systems completely devoid of catecholamines are not available. We have generated a genetic zebrafish model completely devoid of catecholamines by combining mutations in all three genes involved in L-DOPA synthesis: the tyrosine hydroxylase genes th and th2, and tyrosinase tyr. We found catecholamine-deficient zebrafish larvae to be viable and to develop an anatomically normal nervous system including catecholaminergic neuron somata and projections, albeit with reduced cell numbers detected in some clusters. In contrast, selected physiological functions that depend on catecholamines are impaired, including hatching and heart rate regulation upon temperature challenges. Spontaneous locomotion and optomotor behaviors are also impaired. Despite the changes observed, it is surprising that larvae develop a largely normal behavioral repertoire. Our model will be useful to investigate how physiology and neural circuit function are regulated in catecholamine deficient larvae.

developmental biology↗

bioRxiv2024

Sustained neurotrophic factor cotreatment enhances donor and host retinal ganglion cell survival in mice

Retinal ganglion cells (RGCs) lack regenerative capacity in mammals, and their degeneration in glaucoma leads to irreversible blindness. Autologous and allogeneic RGC replacement with stem cell-derived neurons has been established as a promising strategy for vision restoration, but it has been limited by relatively low (<1%) survival rates of donor cells in the hostile microenvironment of a diseased retina and optic nerve. Brain-derived neurotrophic factor (BDNF) and glial-derived neurotrophic factor (GDNF) are known to support the survival of neurons, including RGCs in. vitro and in vivo. Here, we aim to improve donor RGC survival by supplementing our in vitro cultures and in transplants with a slow-release formulation of these neuroprotective agents. We show that slow-release BDNF/GDNF significantly enhances RGC differentiation, survival, and function in vitro. Furthermore, we demonstrated that BDNF/GDNF co-treatment improved mouse and human stem cell-derived donor RGC transplantation outcomes by 2.7- and 15-fold in mice, respectively. Lastly, we show that slow-release BDNF/GDNF provides neuroprotective effects on host RGCs, preserving retinal function in a model of optic neuropathy. Altogether, this approach of engineering the retinal microenvironment with slow-release neurotrophic factors significantly enhances both donor and host neuron survival, representing a promising approach for treating glaucoma and other optic neuropathies. Table of Contents Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/583961v3_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@62d2eorg.highwire.dtl.DTLVardef@1805635org.highwire.dtl.DTLVardef@9bbea7org.highwire.dtl.DTLVardef@101e2f9_HPS_FORMAT_FIGEXP M_FIG C_FIG Engineering the retinal environment with neurotrophic factors to mimic development improves donor and host neuron survival, outgrowth, and function in an optic neuropathy mouse model.

bioengineering↗

bioRxiv2019

Methods for broad-scale plant phenology assessments using citizen scientists’ photographs

Broad-scale plant flowering phenology data has predominantly come from geographically and taxonomically restricted monitoring networks. However, platforms such as iNaturalist, where citizen scientists upload photographs and curate identifications, provide a promising new source of data. Here we develop a general set of best practices for scoring iNaturalist digital records supporting downstream re-use in phenology studies. We focus on a case study group, Yucca, because it has showy flowers and is well documented on iNaturalist. Additionally, drivers of Yucca phenology are not well-understood despite need for Yucca to synchronize flowering with obligate moth pollinators. Finally, evidence of anomalous flowering events have been recently reported, but the extent of those events is unknown. We use best-practices approach to annotate nearly 9,000 Yucca iNaturalist records, and compare the spatiotemporal coverage of this dataset with other broad-scale monitoring resources. Our findings demonstrate that iNaturalist provides unique phenology information, including delineation of extents of unusual flowering events. We also determine if unusual early flowering events impact later, typical flowering periods. Finally, we adapt a plant phenology global knowledge-store to integrate iNaturalist annotation results, supporting broadest reuse. Our approach has application to other plant groups, leveraging rapidly increasing data resources from iNaturalist to study phenology.

ecology↗