Dataset Information

Identifying genes and pathways that respond differently to dietary C:P between old (~700-yr-old) and young (~10-yr-old) resurrected Daphnia pulicaria genotypes that differ in C and P physiology

ABSTRACT: How does environmental change drive phenotypic evolution? We addressed this question using Daphnia genotypes separated by ~1600-years of evolution in a Minnesota lake using methods in resurrection ecology (i.e., reviving dormant eggs from sediments) and found substantial genetic and physiological differentiation. These shifts are highly correlated with anthropogenic environmental change, specifically phosphorus (P)-driven eutrophication. Here, we explore transcriptomic changes that may underlie the observed shifts in P use physiology (see poster by Fricsh et al for a detailed explanation). We compared the transcriptomes of two ancient and two contemporary genotypes in ancient (i.e., low P; LP) and contemporary (i.e., high P; HP) conditions using an 11000-gene microarray. Ancient and contemporary genotypes differed in the number of differentially expressed genes in the HP (mean ± SD; 645 ± 112.95) and LP (1071 ± 211.63) treatments. These results indicate considerable transcriptomic variation between ancient and contemporary genotypes in both dietary treatments, with stressful (LP) conditions invoking differential expression of more genes (t= -2.51; P= 0.04). Moreover, ancient and contemporary genotypes exhibited markedly different transcriptomic responses to dietary treatments. Contemporary genotypes upregulated 84.5 ± 28.99 while ancient genotypes upregulated 413.5 ± 26.16 genes (t= 164.5; P= 0.003). Similarly, ancient (127.5 ± 101.1) and contemporary (316 ± 98.99) genotypes differed significantly in the number of genes downregulated between the HP and LP treatments (t= 125.66; P= 0.005). These results indicate substantial regulatory shifts may underlie the striking physiological differences observed. Further analyses of gene families that were differentially expressed (DE) between ancient and contemporary genotypes revealed several gene families already known to be important in mitigating stoichiometric imbalances driven by P availability. Agglomerative hierarchical cluster analyses of DE loci between ancient and contemporary genotypes indicating age-based clustering will be presented. Together, our theoretical framework based on elemental supply, and unique model system enabled a millennial-scale exploration of the environmental contribution to phenotypic evolution.

ORGANISM(S): Daphnia pulex

PROVIDER: GSE48232 | GEO | 2015/06/01

SECONDARY ACCESSION(S): PRJNA209317

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:A reduction in voluntary feed intake is observed in ruminants consuming nutrient deficient diets, such as those with a low CP or P content, and has been attributed to active metabolic regulation, rather than a physical constraint. The hypothalamus is the key integrator of feed intake regulation in mammals. The objectives of this experiment were to 1) establish a model of metabolic feed intake regulation in ruminants consuming diets of variable CP and P content, and 2) determine key biochemical pathways and influential points of regulation within the hypothalamus. Merino wethers [n = 40; 23.7 ± 1.4 kg liveweight (mean ± SD)] were fed one of five dietary treatments (n = 8/treatment) for 63 days in individual pens. The treatments included targeted combinations of high (H) and low (L) CP (110 and 55 g/kg DM) and high and low P (2.5 and 0.7 g/kg DM) with 9 MJ metabolisable energy (ME) per kg DM which were fed ad libitum (UMEI; unrestricted ME intake) resulting in four experimental diets (HCP-HP-UMEI, LCP-HP-UMEI, HCP-LP-UMEI and LCP-LP-UMEI). An additional nutritional treatment (HCP-HP-RMEI) restricted intake of the HCP-HP diet to an equivalent ME intake of wethers consuming the LCP-LP-UMEI treatment. Wethers offered the LCP-HP-UMEI, HCP-LP-UMEI and LCP-LP-UMEI treatments consumed 42, 32 and 49% less total DM (P ≤ 0.05), respectively than the HCP-HP-UMEI treatment, and this was not attributable to any physical limitation of the rumen. Plasma concentrations of urea nitrogen and inorganic phosphate indicated that these nutrient deficiencies were successfully established. To assess potential mechanisms, RNA-seq was conducted on samples from the arcuate nucleus (ARC), ventromedial hypothalamus and lateral hypothalamus of the wethers, yielding a total of 301, 8 and 148 differentially expressed genes across all pairwise comparisons, respectively. The expression of NPY, AGRP and CARTPT, known for their regulatory role in mammalian feed intake regulation, had a similar transcriptional response in the ARC of wethers consuming nutrient deficient treatments and those consuming a ME restricted treatment, despite these wethers expressing behaviours indicative of satiated and hungry states, respectively. In addition, genes involved with glycolysis (TPI1), the citric acid cycle (CS, OGDH, GLUD1, GOT1) and oxidative phosphorylation (COX5A, ATP5MC1, ATP5F1B, ATP5MC3) were downregulated in the ARC of wethers fed a nutrient deficient (LCP-LP-UMEI) relative to the non-deficient (HCP-HP-UMEI) treatment. In summary, a model for voluntary feed intake restriction was established to determine genome-wide molecular changes in the hypothalamus of young ruminants.

Project description:MicroRNAs (miRNAs) are small noncoding RNAs that negatively regulate gene expression post-transcriptionally. They play a critical role in developmental and physiological processes and have been implicated in the pathogenesis of several diseases including cancer. To identify miRNA signatures associated with different stages of neoplastic development, we examined the expression profile of 776 primate miRNAs in the following cells: primary African green monkey kidney (pAGMK) cells; spontaneously immortalized, non-tumorigenic, low-passage VERO cells (10-87 LP); tumorigenic, high-passage VERO cells (10-87 HP); and a cell line (10-87 T) derived from a 10-87 HP cell tumor xenograft in athymic nude mice. When compared with pAGMK cells, the majority of miRNAs were expressed at lower levels in 10-87 LP, 10-87 HP, and 10-87 T cells. We identified 10 up-regulated miRNAs whose level of expression correlated with VERO cell evolution from a non-tumorigenic phenotype to a tumorigenic phenotype. Several miRNAs that were components of the tumorigenic phenotype-specific signatures in our AGMK model are also found in a variety of human tumors. This may prove to be of general relevance to the biology of neoplastic development as it occurs both in vivo as well as in vitro. In addition, one or more of these miRNAs could be potential biomarkers for the expression of the tumorigenic phenotype of VERO cells. The spontaneousely transformed VERO cells, non-tumorigenic, were pasasged at low density in culture up to 250. The high passage (p250) was found to be tumorigenic. The cell line from xenograft of high passage was also established. We then evaluated patterns of miRNA expression in pAGMK cells and in derivatives of the 10-87 VERO cell line (10-87 LP cells, 10-87 HP cells, and 10-87 T cells) in an attempt to identify the miRNAs whose altered expression might correlate with, and perhaps be involved in, the evolution of the neoplastic phenotypes that occurred during passage of these AGMK cells in tissue culture. performed high-throughput miRNA profiling to audit the expression level of miRNAs in pAGMK cells and in VERO cells at non-tumorigenic and tumorigenic stages of neoplastic development. The analysis involved pAGMK cells, non-tumorigenic 10-87 low-passage VERO cells (10-87 LP) tumorigenic, high-passage VERO cells (10-87 HP) and a cell line (10-87 T) derived from a 10-87 HP cell tumor xenograft in athymic nude mice.

Dataset Information

Identifying genes and pathways that respond differently to dietary C:P between old (~700-yr-old) and young (~10-yr-old) resurrected Daphnia pulicaria genotypes that differ in C and P physiology

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure