Biology subjects

Torres, D.

Publications and source records attributed to Torres, D..

3 recordsLinked to original sources

bioRxiv2021

Sub-second multi-channel magnetic control of select neural circuits in behaving flies

Precisely timed activation of genetically targeted cells is a powerful tool for studying neural circuits and controlling cell-based therapies. Magnetic control of cell activity or "magnetogenetics" using magnetic nanoparticle heating of temperature-sensitive ion channels enables remote, non-invasive activation of neurons for deep-tissue applications and studies of freely behaving animals. However, the in vivo response time of thermal magnetogenetics is currently tens of seconds, which prevents the precise temporal modulation of neural activity similar to light-based optogenetics. Moreover, magnetogenetics has not provided a means to selectively activate multiple channels to drive behavior. Here we produce sub-second behavioral responses in Drosophila melanogaster by combining magnetic nanoparticles with a rate-sensitive thermoreceptor (TRPA1-A). Furthermore, by tuning the properties of magnetic nanoparticles to respond to different magnetic field strengths and frequencies, we can achieve sub-second, multichannel stimulation, analogous to multi-color optogenetic stimulation. These results bring magnetogenetics closer to the temporal resolution and multiplexed stimulation possible with optogenetics while maintaining the minimal invasiveness and deep-tissue stimulation only possible by magnetic control.

bioengineering↗

bioRxiv2021

Binocular vs. monocular recovery experience differentially promote recovery from visual deficits in a mouse model of amblyopia

Altered visual experience during monocular deprivation (MD) profoundly changes in ocular dominance (OD) in the developing primary visual cortex (V1). MD-driven changes in OD are an experimental model of amblyopia, where early-life alterations in vision lead visual disruption in adulthood. Current treatments for amblyopia include patching of the dominant eye, and more recently-developed binocular therapies. However, the relative impact of monocular vs. binocular recovery experiences on recovery of function in V1 is not well understood. Using single-unit recording, we compared how binocular recovery [BR] or reverse occlusion [RO] of identical duration and content affects OD and visual response recovery in mouse binocular V1 after a period of MD. We also tested how BR and RO affected MD-driven alterations of parvalbumin expression, and visually-driven expression of cFos in parvalbumin-positive and negative neurons. Finally, we tested how BR and RO affected recovery of normal visual acuity for the two eyes in the context of visually-driven behavior. We find that BR is quantitatively superior with respect to normalization of V1 neurons OD, visually-driven cFos expression, and visual acuity for the two eyes. However, MD-driven changes in the firing rate and response properties of V1 principal neuron and fast-spiking interneuron populations do not recover fully after either BR or RO. Binocular matching of orientation preference also remains disrupted in V1 neurons after both forms of recovery experience. Thus BR and RO, analogs of differing treatment regimens for amblyopia, differentially impact various aspects of visual recovery in a mouse model for amblyopia. Significance StatementAmblyopia resulting from altered childhood eye function is a leading cause of lifelong vision loss. Treatment typically involves patching of the dominant eye (forcing monocular visual experience), and produces only partial recovery of vision. Using a well-established mouse model of amblyopia, we directly compared how two types of visual experiences influence recovery of visual function. Our findings suggest that binocular vs. monocular visual experience differentially effect restoration of normal visual responses in cortical neurons, visually-driven neuronal gene expression, and visual acuity. Understanding how the quality of recovery experience impacts visual system recovery in amblyopia should provide critical insights for clinical strategies for its treatment.

neuroscience↗

bioRxiv2020

Comparative genomics of Verticillium dahliae isolates reveals the in planta-secreted effector protein recognized in V2 tomato plants

Plant pathogens secrete effector molecules during host invasion to promote host colonization. However, some of these effectors become recognized by host receptors, encoded by resistance genes, to mount defense response and establish immunity. Recently, a novel resistance was identified in tomato, mediated by the single dominant V2 locus, to control strains of the soil-borne vascular wilt fungus Verticillium dahliae that belong to race 2. We performed comparative genomics between race 2 strains and resistance-breaking race 3 strains to identify the avirulence effector that activates V2 resistance, termed Av2. We identified 277 kb of race 2-specific sequence comprising only two genes that encode predicted secreted proteins, both of which are expressed by V. dahliae during tomato colonization. Subsequent functional analysis based on genetic complementation into race 3 isolates confirmed that one of the two candidates encodes the avirulence effector Av2 that is recognized in V2 tomato plants. The identification of Av2 will not only be helpful to select tomato cultivars that are resistant to race 2 strains of V. dahliae, as the corresponding V2 resistance gene has not yet been mapped, but also to monitor adaptations in the V. dahliae population to deployment of V2-containing tomato cultivars in agriculture.

plant biology↗