Biology subjects

Dey, P.

Publications and source records attributed to Dey, P..

3 recordsLinked to original sources

bioRxiv2026

Dynamic microtubules drive yolk-cytoplasm segregation in the syncytial Drosophila embryo

Yolk-cytoplasm segregation is among the earliest spatial organization events in the developing embryo of many oviparous animals. The segregation process is intimately linked to early embryonic cleavage and pattern formation, and exhibits a wide range of spatial and temporal diversity. However, the underlying cytoskeletal mechanism remains largely unknown, except for a small number of species. Using quantitative live imaging, we investigated yolk segregation in the Drosophila embryo during the syncytial nuclear cycles 11-14. We find that the yolk vesicles move progressively inward in spatial and temporal coordination with the inward expanding microtubule networks that are nucleated from centrosomes positioned at the cortex, whereas cortical actin meshwork remains spatially restricted. Using the gnu RNAi embryo to decouple nuclear migration and division from cytoskeletal dynamics, we establish causality with targeted pharmacological disruption and find that microtubule dynamics is required for yolk segregation, while depolymerization of actin has no discernible effect. In support of a mechanism of growth-propelled passive displacement, microtubule plus end comets come in apparent contact with yolk vesicles, and injected, inert microbeads are displaced towards the embryo center presumably by the same pushing force. These findings identify microtubule polymerization as a predominant driver of yolk-cytoplasm segregation in Drosophila and suggest that diverse cytoskeletal mechanisms evolved to accomplish this crucial reorganization process

developmental biology↗

bioRxiv2018

Detection of cellular microRNAs with programmable DNA nanoswitches

MicroRNAs are short non-coding regulatory RNAs that are increasingly used as disease biomarkers. Detection of microRNAs can be arduous and expensive, and often requires amplification, labeling, or radioactive probes. Here we report a single-step, non-enzymatic detection assay using conformationally responsive DNA nanoswitches. Termed miRacles (microRNA activated conditional looping of engineered switches), our assay has sub-attomole sensitivity and single-nucleotide specificity using an agarose gel electrophoresis readout. We detect cellular microRNAs from nanogram-scale RNA extracts of differentiating muscle cells, and demonstrate multiplexed detection of several microRNAs from one biological sample. We demonstrate one-hour detection without expensive equipment or reagents, making this assay a compelling alternative to qPCR and Northern blotting.\n\nSignificance statementDetection of microRNAs play a key role in biological research and medical diagnostics, and current detection methods are expensive and require sophisticated processes. We present microRNA activated conditional looping of engineered switches (miRacles), a mix-and-read strategy that is based on conformational changes of DNA nanoswitches upon binding a target microRNA. MiRacles has a sensitivity of [~]4 copies/cell and specificity of a single nucleotide, and can be performed in one hour at a fraction of the cost of traditional microRNA detection techniques. Our method can also be multiplexed to detect multiple microRNAs from one biological sample. The minimalistic miRacles assay has immediate application in biomedical research and longer term potential as a clinical tool.

bioengineering↗

bioRxiv2017

Correction of the Framingham Risk Score Data Reported in SPRINT

This report describes an error in the Framingham Risk Score data presented in the original SPRINT publication.1 The data, presented in Table 1 of the main SPRINT publication in the New England Journal of Medicine and made available to SPRINT Challenge participants, incorrectly calculated the level of baseline cardiovascular risk of the study participants using the Framingham Risk Score. The correct calculation increased the number of participants identified as having >15% 10-year risk from 5737 to 7089, a change from 61% to 76% of the total study population. This information is important for researchers attempting to validate and extend the trials findings and is particularly germane because the recently released American Heart Association/American College of Cardiology blood pressure guidelines changed blood pressure targets for pharmacologic therapy only for high-risk individuals.\n\nO_TBL View this table:\norg.highwire.dtl.DTLVardef@5ed416org.highwire.dtl.DTLVardef@1b60929org.highwire.dtl.DTLVardef@137409org.highwire.dtl.DTLVardef@127169borg.highwire.dtl.DTLVardef@13d3666_HPS_FORMAT_FIGEXP M_TBL O_FLOATNOTable 1C_FLOATNO O_TABLECAPTIONRegression Coefficients for Cox regression model used to predict CVD risk4\n\nC_TABLECAPTION C_TBL

clinical trials↗