Biology subjects

Seppala, O.

Publications and source records attributed to Seppala, O..

2 recordsLinked to original sources

bioRxiv2020

Transcriptome profiling of a multiuse model species Lymnaea stagnalis (Gastropoda) for ecoimmunological research

Host immune function can contribute to numerous ecological/evolutionary processes. Ecoimmunological studies, however, typically use one/few phenotypic immune assays and thus do not consider the complexity of the immune system. Therefore, "omics" resources that allow quantifying immune activity across multiple pathways are needed for ecoimmunological models. We applied short-read based RNAseq (Illumina NextSeq 500, PE-81) to characterise transcriptome profiles of a multipurpose model species Lymnaea stagnalis (Gastropoda). We used a genetically diverse snail stock and exposed individuals to immune elicitors (injury, bacterial/trematode pathogens) and changes in environmental conditions that can alter immune activity (temperature, food availability). Immune defence factors identified in the de novo assembly indicated uniform aspects of molluscan immunity: pathogen-recognition receptors (PRR) and lectins activate Toll-like receptor (TLR) pathway and cytokines that regulate cellular and humoral defences. However, also apparent differences to other taxa were detected (i.e., modest numbers of antimicrobial peptides and fibrinogen related proteins). Identified factors also indicate that several of them might contribute to the phenotypic immune assays used on this species. Experimental treatments revealed factors from non-self recognition (lectins) and signalling (TLR pathway, cytokines) to effectors [e.g., antibacterial proteins, phenoloxidase (PO) enzymes] whose gene expression depended on immune activations and environmental conditions, as well as components of snail physiology/metabolism that may drive these effects. Interestingly, gene expression of many factors (e.g., PRR, lectins, cytokines, PO enzymes, antibacterial proteins) showed high among-individual variation. Such factors are important to include in ecoimmunological research because they may explain among-individual differences in parasite resistance and fitness in natural populations.

genomics↗

bioRxiv2018

Direct and transgenerational effects of an experimental heat wave on early life stages in a freshwater snail

Global climate change imposes a serious threat to natural populations of many species. Estimates of the effects of climate change-mediated environmental stresses are, however, often based only on their direct effects on organisms, and neglect the potential transgenerational effects. We investigated whether high temperature (i.e. an experimental heat wave) that is known to reduce performance of adult Lymnaea stagnalis snails affects their offspring through maternal effects. Specifically, we tested whether eggs and hatched juveniles are affected by maternal thermal environment, and how strong these effects are compared with direct effects of temperature on offspring. We examined the effect of maternal thermal environment (15{degrees}C versus 25{degrees}C) on per offspring investment (egg size), and the role of both maternal and offspring thermal environments (15{degrees}C versus 25{degrees}C) on hatching success and developmental time of eggs, offspring survival after hatching, and hatchling size at the age of five weeks. Exposure of mothers to high temperature increased hatching success of eggs, and also made the onset of hatching earlier. However, high maternal temperature reduced the survival and the final size of hatched juveniles. Direct effects of high temperature on offspring survival were negative (both eggs and hatchlings), but increased the developmental rate and growth of those eggs and hatchlings that survived. Interestingly, the magnitude of transgenerational effects of high temperature on hatching success of eggs and hatchling survival were similar to its direct effects. This indicates that heat waves can affect natural populations through transgenerational effects, and that the magnitude of such effects can be equally strong to the direct effects of temperature, although this depends on the trait considered. Our results highlight the importance of considering transgenerational effects of climate warming when estimating its effects in the wild.

ecology↗