Biology subjects

Diz, A. P.

Publications and source records attributed to Diz, A. P..

3 recordsLinked to original sources

bioRxiv2024

Evolution of thermal tolerance in marine diatoms: Metabolic strategies under heat stress.

In the last decade, numerous laboratory experiments have demonstrated that when marine phytoplankton are exposed to thermal stress, they can evolve high temperature tolerance in a short time (weeks to months). This evolutionary potential may ensure the persistence of marine phytoplankton species under current and future global warming. However, the effect of such adaptation on the phytoplankton interaction with the environment and other organisms depends on how cellular metabolism shifts during the evolutionary process. In order to elucidate which cellular strategies allow the emergence of thermo-tolerant populations, we analyzed the proteomics response of a marine diatom (Chaetoceros simplex) to both thermal acclimation and evolutionary adaptation. We found that high temperature-tolerant populations exhibit a conservative cellular strategy when acclimated to high, above-optimal temperature, where recycling and reallocation is favored at the expense of new structures biosynthesis. While this strategy gives the populations that evolved high temperature tolerance an advantage under thermal stress, the shift to resource reallocation may explain the absence of high-temperature adaptation when cells are exposed to low nitrate availability.

ecology↗

bioRxiv2024

Comprehensive Proteomic, Ultrastructural and Functional Analysis of Cryopreservation Effects on Marine Mussel Oocytes

Cryopreservation is a valuable tool for preserving marine genetic diversity and supporting selective breeding in aquaculture. The blue mussel (Mytilus galloprovincialis) is an important species for the aquaculture industry and a useful model for studying cryopreservation in marine invertebrates. Declining mussel seed availability over the past decade, combined with the growing demand for year-round hatchery production, has increased interest in developing effective cryopreservation methods for gametes and embryos. However, cryopreservation remains challenging, particularly for marine invertebrate oocytes, as it requires balancing cryoprotectant cytotoxicity with sufficient cell protection during freezing and thawing. Moreover, the molecular, structural, and functional changes associated with oocyte cryopreservation in invertebrates are still poorly understood. This study examines the effects of two commonly used cryoprotectants, dimethyl sulfoxide (DMSO) and ethylene glycol (EG), on M. galloprovincialis oocytes under a monitored slow freezing (MSF) protocol. Using an integrative analytical approach combining proteomics, functional assessments, and ultrastructural analyses, we provide a comprehensive understanding of cryoprotectant-induced changes. Our findings reveal that cryoprotectants cause significant proteomic alterations, with DMSO having more pronounced effects. These alterations are associated with increased oxidative stress, an insufficient antioxidant response, and disruptions in meiosis restart mechanisms, ultimately delaying larval development. Cryoprotectant-induced oxidative stress may also weaken the oocyte membrane, leading to rupture during the MSF protocol and subsequent fertilisation failure post-thawing. These results provide evidence that EG is less cytotoxic than DMSO and suggest that supplementing cryoprotectants with antioxidants and membrane stabilizers could enhance success rates in the cryopreservation of oocytes from mussels and other marine invertebrate species.

developmental biology↗

bioRxiv2023

Spatial and long-term temporal evolution of a marine mussel hybrid zone (Mytilus spp.) in SW England

The study of spatial and temporal changes in hybrid zones offers important insights into speciation. Earlier studies on hybrid populations of the marine mussel species Mytilus edulis and M. galloprovincialis in SW England provided evidence of admixture but were constrained by the limited number of molecular markers available. We use 57 highly ancestry-informative SNPs, most of which have been mapped genetically, to provide evidence of distinctive differences between highly admixed populations in SW England and asymmetrical introgression from M. edulis to M. galloprovincialis. We combine the genetic study with analysis of phenotypic traits of potential ecological and adaptive significance. We demonstrate that hybrid individuals have brown mantle edges unlike the white or purple in the parental species, suggesting allelic or non-allelic genomic interactions. We report differences in gonad development stage between the species consistent with a prezygotic barrier between the species. By incorporating results from publications dating back to 1980 we confirm the long-term stability of the hybrid zone consistent with higher viability of M. galloprovincialis. This stability coincides with a dramatic change in temperature of UK coastal waters and suggests that these hybrid populations might be resisting the effects of global warming. However, a single SNP locus associated with the notch 2 signalling transmembrane protein shows a markedly different pattern of variation to the others and might be associated with adaption of M. galloprovincialis to colder northern temperatures.

evolutionary biology↗