BackgroundThe blood transcriptome can reflect both systemic exposures and pathological changes in other organs of the body because immune cells recirculate through the blood, lymphoid tissues, and affected sites. In human and veterinary medicine, blood transcriptome analysis has been used successfully to identify markers of disease or pathological conditions, but can be confounded by large seasonal changes in expression. In comparison, the use of transcriptomic based analyses in wildlife has been limited. Here we report a longitudinal study of four managed bottlenose dolphins located in Waikoloa, Hawaii, serially sampled (approximately monthly) over the course of 1 year to establish baseline information on the content and variation of the dolphin blood transcriptome.ResultsIllumina based RNA-seq analyses were carried out using both the Ensembl dolphin genome and a de novo blood transcriptome as guides. Overall, the blood transcriptome encompassed a wide array of cellular functions and processes and was relatively stable within and between animals over the course of 1 year. Principal components analysis revealed moderate clustering by sex associated with the variation among global gene expression profiles (PC1, 22 % of variance). Limited seasonal change was observed, with < 2.5 % of genes differentially expressed between winter and summer months (FDR < 0.05). Among the differentially expressed genes, cosinor analysis identified seasonal rhythmicity for the observed changes in blood gene expression, consistent with studies in humans. While the proportion of seasonally variant genes in these dolphins is much smaller than that reported in humans, the majority of those identified in dolphins were also shown to vary with season in humans. Gene co-expression network analysis identified several gene modules with significant correlation to age, sex, or hematological parameters.ConclusionsThis longitudinal analysis of healthy managed dolphins establishes a preliminary baseline for blood transcriptome analysis in this species. Correlations with hematological parameters, distinct from muted seasonal effects, suggest that the otherwise relatively stable blood transcriptome may be a useful indicator of health and exposure. A robust database of gene expression in free-ranging and managed dolphins across seasons with known adverse health conditions or contaminant exposures will be needed to establish predictive gene expression profiles suitable for biomonitoring.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3020-8) contains supplementary material, which is available to authorized users.

No abstract

No abstract

No abstract

We have successfully isolated cells with stem-like properties from bottlenose dolphin (Tursiops truncatus) umbilical cord. Our results show that this cetacean species has embryonic fetal and adult stem cells as do humans and other studied mammals. This accomplishment allows to eventually investigate whether dolphins, due to their unique adaptations to aquatic environments, have special stem cell lineages or distinctive mechanisms of cell programming. Further characterization of their potency to differentiate into multiple cell lineages would fulfill numerous applicative purposes. We characterized, developed and refined a new protocol for obtaining potential stem cells from umbilical cord tissues of the bottlenose dolphin. Tissue samples were taken from umbilical cords of successful deliveries immediately after placenta ejection and collection from the water. Umbilical cord samples (2-3 cm 3 ) were excised and subjected to enzymatic digestion and mechanical dissociation. Viable cells from specimens resident in the Oceanografic Valencia were cultured and subsequently isolated and tested for pluripotent characteristics (cell morphology, phenotype and expression of surface markers). Cell viability was confirmed also after freezing/thawing. The established protocol is suitable for collection/isolation/culture of dolphin potential mesenchymal stem cells from dolphin umbilical cord, which can be deposited in cell banks for future research needs.