Changing shape and reducing projected area in flow are two distinct strategies employed by flexible seaweeds to resist drag. Flexible reconfiguration contributes to the uncertainty of drag extrapolation, and researchers should use caution when predicting drag and dislodgement of seaweeds in the field.

The California ribbed mussel Mytilus californianus (Conrad 1837) is a dominant intertidal species that ranges from Alaska (USA) to Baja California (Mexico) along the west coast of North America. Despite its broad latitudinal range, which results in populations living at widely different temperatures, multiple studies have concluded that this species is genetically homogenous. This may be due to high gene flow, which would inhibit local adaptation, and lack of strong post-settlement selection pressure, which would not favor shifts in allelic frequencies among sites. We investigated several physiological traits that show temperature-adaptive variation in other Mytilus species. We sampled populations of M. californianus at 7 sites across 33° of latitude to test for the possibility of local adaptation or phenotypic plasticity. Individuals acclimated to common conditions were examined for possible differences in whole-organism thermal tolerance. The most northern population (Tatoosh Island) had a significantly lower survival rate following an acute heat stress event than the other populations. Additional physiological processes were examined that affect thermal optima and limits: critical thermal maximum (Hcrit) of cardiac function and metabolic capacity (as indexed by tissue activity of an indicator enzyme, malate dehydrogenase). Tatoosh mussels had a significantly lower Hcrit than other sites, indicating that this population may be adapted to cooler conditions compared to other populations. Metabolic activity did not correlate with latitude of collection. Phenotypic plasticity at the adult stage did not explain differences in thermal tolerance. Thus, genetic differences (local adaptation or balanced polymorphism), developmental plasticity, maternal effects, or within-site thermal heterogeneity may be responsible for the observed variation among populations.KEY WORDS: Adaptation · Environmental variability · Latitudinal differences · Mytilus · Physiology · Stress · Temperature · Phenotypic plasticity Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 450: [93][94][95][96][97][98][99][100][101][102][103][104][105] 2012 Suchanek 1978, Sarver & Foltz 1993, Addison et al. 2008, which extends over 4000 km and across 33° of latitude from Baja California (Mexico) to the Gulf of Alaska (USA). Addison et al. (2008) attributed the genetic homogeneity they found in M. californianus to high gene flow (due to a long pelagic larval duration and year-round spawning), but also suggested that lack of a strong selective gradient across its range, rather than high gene flow per se, might be a key element underlying the broad-scale genetic homogeneity.Several strong and persistent environmental gradients do occur in the rocky intertidal environment along the west coast of North America, including water and air temperatures, pH, and nutrients (Menge et al. 1997, Helmuth et al. 2006, Feely et al. 2008. Genetic differentiation can occur under high gene flow conditions, and popula...

DNA methylation (DNAm) has been shown to play a role in mediating food allergy, however, the mechanism by which it does so is poorly understood. In this study, we used targeted NextGen bisulfite sequencing to evaluate DNAm levels in 125 targeted highly informative genomic regions containing 602 CpG sites on 70 immune-related genes to understand whether DNAm can differentiate peanut allergy (PA) vs non-allergy (NA). We found PA-associated DNAm signatures associated with 12 genes (7 potentially novel to food allergy, 3 associated with Th1/Th2, and 2 associated with innate immunity) as well as DNAm signature combinations with superior diagnostic potential compared to serum peanut specific-IgE for PA vs. NA. Further, we found that following peanut protein stimulation, peripheral blood mononuclear cell (PBMCs) from PA participants showed increased production of cognate cytokines compared to NA participants. The varying responses between PA and NA participants may be associated with the interaction between the modification of DNAm and the interference of environment. Using Euclidean distance analysis, we found that the distances of methylation profile comprising 12 DNAm signatures between PA and NA pairs in monozygotic (MZ) twins were smaller than that in randomly paired genetically unrelated individuals, suggesting that PA related DNAm signatures may be associated with genetic factors.

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