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Morrissey, M.

Publications and source records attributed to Morrissey, M..

4 recordsLinked to original sources

A self-organizing single-cell morphology circuit optimizes Podophrya collini predatory trap structure

Cellular structure self-organizes through an interplay between internal mechanisms and external cues. In predatory ciliates, structures that capture prey obtain the resources needed for their construction, creating feedback between environmental inputs and morphological outputs. Here, we describe a self-organizing single-cell morphology circuit that adaptively optimizes the predatory trap structure of the suctorian Podophrya collini. These trap structures ensnare large cellular targets using an array of straw-like tentacles that siphon out prey cytoplasm upon contact with their tips. We find that trap architecture scales anisotropically, favoring tentacle number over length, to construct traps that maximize capture probability for the resources on hand. Drug perturbations, transcriptomics, proteomics, and expansion microscopy define distinct molecular and structural requirements that regulate trap structure maintenance and tentacle biogenesis. We integrate these findings into a mathematical model that explains the adaptive scaling of the trap and that makes predictions we confirm experimentally. More broadly, this circuits architecture provides a general-purpose control logic for organizing the number and size of sub-cellular structures applicable to other natural and engineered cellular systems.

cell biology↗

Orthogonal and Robust Analytics Enable Reproducible and Scalable Manufacturing of High Purity Extracellular Vesicles Derived from Mesenchymal Stromal Cells

The development of extracellular vesicle (EV) based therapeutics requires robust analytical assays and scalable downstream processing (DSP) strategies to ensure product quality and reproducibility. In this study, we established an analytical toolbox comprising scattering and fluorescence mode nanoparticle tracking analysis (NTA), fluorescence-based flow cytometry (Fl-FC), and multi-detector analytical size exclusion chromatography. Liposomes, selected for their physicochemical similarity to EVs, were used as reference materials to optimize assay parameters, fluorescence labeling conditions, and dynamic range, minimizing artifacts such as photobleaching and masking effects. Using these optimized analytical tools, we designed a scalable DSP workflow for human bone marrow mesenchymal stromal cell (hBM-MSC) derived EVs, incorporating clarification, tangential flow filtration (TFF), ion exchange chromatography (IEX), buffer exchange, and sterile filtration. IEX chromatography resulted in the elution of two cell-secreted populations, with similar scattering signals while eluate 1 showed approximately 30 times higher absorbance signal compared to eluate 2. Transmission electron microscopy revealed that eluate 1 contained non-vesicular extracellular particles (NVEPs), and eluate 2 was enriched in EVs and showed higher expression of positive markers such as CD81 and CD73 using Simple Western. Additionally, the two IEX eluates showed different proteomic and lipidomic profiles. Then the analytical toolbox was utilized to monitor the DSP process in terms of particle recovery and impurity removal throughout the process determining the high purity level of the final EV preparation. Together, these results demonstrate that orthogonal analytics coupled to a scalable DSP yield reproducible MSC-EV preparations while depleting commonly co-isolated NVEPs. This practical framework advances process analytics of MSC-EV manufacturing and supports reporting of identity, purity, and function aligned with existing guidelines in the field. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/672476v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@142ff8aorg.highwire.dtl.DTLVardef@196c0bforg.highwire.dtl.DTLVardef@485c36org.highwire.dtl.DTLVardef@9dff39_HPS_FORMAT_FIGEXP M_FIG C_FIG Liposomes were used as reference materials to optimize single particle analytics as well as multi detector analytical chromatography to assess particle recovery and impurity removal. This optimized analytical toolbox enabled accurate monitoring of downstream processing steps, establishing a robust workflow for reproducible and scalable mesenchymal stromal derived extracellular vesicles bioprocessing.

bioengineering↗

Spatiotemporal variation in size-dependent growth rates in small isolated populations of Arctic charr (Salvelinus alpinus)

As a key life-history trait, growth rates are often used to measure individual performance and to inform parameters in demographic models. Furthermore, intra-specific trait variation generates diversity in nature. Therefore, partitioning out and understanding drivers of spatiotemporal variation in growth rate is of fundamental interest in ecology and evolution. However, this has rarely been attempted due to the amount of individual-level data required through both time and space, and issues with missing data in important covariates. Here we implemented a Bayesian state-space model using individual-level data from 20 populations of Arctic charr (Salvelinus alpinus) across 15 capture occasions, which allowed us to: (1) integrate over the uncertainty of missing recapture records; (2) robustly estimate size-dependence; and (3) include a covariate (water temperature) that contained missing data. Interestingly, although there was substantial spatial, temporal, and spatiotemporal variation in growth rate, this was only weakly associated with variation in water temperature and almost entirely independent of size, suggesting that spatiotemporal variation in other environmental conditions affected individuals across sizes similarly. This fine-scale spatiotemporal variation emphasises the importance of local conditions and highlights the potential for spatiotemporal variation in a size-dependent life-history trait, even when environmental conditions are apparently very similar.

ecology↗

Animal personality adds complexity to the processes of adaptive divergence and speciation.

Divergent selection is a powerful driver of speciation and has been widely studied in relation to the physical characters of organisms. Because evolution of behavioural traits may contribute to evolutionary processes, we explored how consistent variation in behaviours may affect the process of adaptive divergence and speciation. We studied whether two sympatric morphs of Arctic charr (Salvelinus alpinus) have recently evolved genetically-based differences in personality that conform to their respective ecological niches, and whether these differences contribute to reproductive isolation by generating maladaptive hybrid behaviours. Studying three aspects of behavioural variation (average trait value, consistent individual differences and trait covariance), we assessed the sociality and risk-taking propensity of hybrid and pure-morph offspring reared in common conditions. Contrary to expectations, the two morphs did not differ in the average values of these traits but showed different behavioural syndromes (trait covariances). While the hybrids did not differ from either morph in their average behavioural responses, they showed less individual consistency in these behaviours and a different set of behavioural syndromes. Differences between morphs and their hybrids in other behavioural aspects than their average behavioural responses suggest that our understanding of speciation processes can benefit from an integrative view of behavioural variation.

evolutionary biology↗