Biology subjects

Purvis, E. M.

Publications and source records attributed to Purvis, E. M..

2 recordsLinked to original sources

bioRxiv2025

Astrocyte Transcriptomics in a Three-Dimensional Tissue-Engineered Rostral Migratory Stream

The glial tube is a longitudinal structure predominantly composed of densely bundled, aligned astrocytes that projects from subventricular zone (SVZ) to olfactory bulb. Neural precursor cells (NPCs) generated in the SVZ migrate through this glial tube - referred to as the rostral migratory stream (RMS) - to replace olfactory bulb interneurons in the mammalian brain. RMS astrocytes have distinct morphological and functional characteristics facilitating their unique purpose as an endogenous living scaffold directing NPC migration and maturation. However, the transcriptomic factors underlying these unique structure-function attributes versus standard stellate astrocytes have not been examined. We previously developed biofabrication techniques to create the first tissue-engineered rostral migratory stream (TE-RMS) that replicates key features of the glial tube in vivo. We have shown that TE-RMS astrocytes exhibit elongated nuclei, longitudinally aligned intermediate filaments, and enrichment of key functional proteins - cytoarchitectural and surface features characteristic of native RMS astrocytes. In the current study, we performed RNAseq on TE-RMS astrocytes in comparison to planar astrocyte cultures to identify gene expression patterns that may underlie their profound morphological and functional differences. Remarkably, we found 4008 differentially expressed genes in TE-RMS astrocytes, with 2076 downregulated (e.g. LOC690251, ccn5) and 1932 upregulated (e.g. lrrc45, cntn1) compared to planar astrocytes. Moreover, there were 256 downregulated and 91 upregulated genes with >3-fold change. We also conducted analyses of gene sets related to cytoskeleton and nuclear structure, revealing greatest enrichment of actin-related components. Overall, the TE-RMS offers a platform to study interplay between transcriptomic and cytoarchitectural dynamics in a unique astrocyte population.

bioengineering↗

bioRxiv2024

Interactive effects of temperature and salinity on metabolism and activity of the copepod Tigriopus californicus

In natural environments two or more abiotic parameters often vary simultaneously, and interactions between covarying parameters frequently result in unpredictable, non-additive biological responses. To better understand the mechanisms and consequences of interactions between multiple stressors it is important to study their effects on both survival and performance. The splashpool copepod Tigriopus californicus tolerates extremely variable abiotic conditions and exhibits a non-additive, antagonistic interaction resulting in higher survival when simultaneously exposed to high salinity and acute heat stress. Here, we investigated T. californicus response in activity and oxygen consumption under simultaneous manipulation of salinity and temperature to identify if this interaction also arises in these sublethal measures of performance. Oxygen consumption and activity rates decreased with increasing assay salinity. Oxygen consumption also sharply increased in response to acute transfer to lower salinities, an effect that was absent upon transfer to higher salinities. Elevated temperature led to reduced rates of activity overall, resulting in no discernible impact of increased temperature on routine metabolic rates. This suggests that swimming activity has a non-negligible effect on copepods metabolic rates and must be accounted for in metabolic studies. Temperature also interacted with assay salinity to affect activity and with acclimation salinity to affect routine metabolic rates upon acute salinity transfer, implying that the sublethal impacts of these co-varying factors are also not predictable from experiments that study them in isolation. Summary StatementTemperature and salinity interact to affect metabolic rate in the copepod Tigriopus californicus, but the stressors individual effects and their interaction are complicated by concurrent changes in activity.

physiology↗