Hyper- and Hypo-Osmoregulatory Performance of Atlantic Salmon (Salmo salar) Smolts Infected With Pomphorhynchus tereticollis (Acanthocephala)

Migratory species must cope with different parasite communities in different environments, but little is known about the ecophysiological effects of parasites on migratory performance. Some species/strains of acanthocephalan parasites in the genus Pomphorhynchus use anadromous salmonids as preferred definitive hosts, perforating the intestines, destroying mucosa and inducing inflammation–all of which might affect osmoregulatory function during transition between freshwater and marine environments. We used genetic barcoding to identify acanthocephalans in the intestines of wild Irish Atlantic salmon (Salmo salar L.) smolts as being the recently taxonomically resurrected species Pomphorhynchus tereticollis. We then investigated whether natural infection intensities of this parasite were associated with reduced osmoregulatory performance, as measured by plasma chloride concentrations, or potentially elevated stress, as measured by blood glucose, of hosts in freshwater or saltwater environments (24 or 72 h in ∼26PPT salt water, reflecting salinities of coastal waters through which smolts migrate). Although infection prevalence was high amongst sampled smolts, no associations were found within or across treatment groups between parasite abundance and plasma chloride concentrations or blood glucose levels. We found no intestinal perforations that would indicate P. tereticollis had recently vacated the intestines of smolts in either of the saltwater groups. Exploratory sampling in the 2 years preceding the experiment indicated that parasite prevalence and abundance are consistently high and comparable to the experimental individuals. Collectively, these results indicate that naturally occurring abundances of P. tereticollis do not reduce osmoregulatory function or affect blood glucose content in fresh water or within 72 h of entering coastal waters, although delayed pathologies affecting marine survival may occur. Future consideration of ecophysiological interactions between anadromous fish hosts and their parasites across different osmotic environments should provide general insights into coevolution between migratory hosts and their parasites.

Genomic Adaptations to Salinity Resist Gene Flow in the Evolution of Floridian Watersnakes

The migration-selection balance often governs the evolution of lineages, and speciation with gene flow is now considered common across the tree of life. Ecological speciation is a process that can facilitate divergence despite gene flow due to strong selective pressures caused by ecological differences; however, the exact traits under selection are often unknown. The transition from freshwater to saltwater habitats provides strong selection targeting traits with osmoregulatory function. Several lineages of North American watersnakes (Nerodia spp.) are known to occur in saltwater habitat and represent a useful system for studying speciation by providing an opportunity to investigate gene flow and evaluate how species boundaries are maintained or degraded. We use double digest restriction-site associated DNA sequencing to characterize the migration-selection balance and test for evidence of ecological divergence within the Nerodia fasciata-clarkii complex in Florida. We find evidence of high intraspecific gene flow with a pattern of isolation-by-distance underlying subspecific lineages. However, we identify genetic structure indicative of reduced gene flow between inland and coastal lineages suggesting divergence due to isolation-by-environment. This pattern is consistent with observed environmental differences where the amount of admixture decreases with increased salinity. Furthermore, we identify significantly enriched terms related to osmoregulatory function among a set of candidate loci, including several genes that have been previously implicated in adaptation to salinity stress. Collectively, our results demonstrate that ecological differences, likely driven by salinity, cause strong divergent selection which promotes divergence in the N. fasciata-clarkii complex despite significant gene flow.

Plasticity in gene expression facilitates invasion of the desert environment in house mice

Understanding how organisms adapt to new environments is a key problem in evolution, yet it remains unclear whether phenotypic plasticity generally facilitates or hinders this process. Here we studied the evolved and plastic responses to water stress in lab-born descendants of wild house mice (Mus musculus domesticus) collected from desert and non-desert environments. Using a full sib design, we measured organismal phenotypes and gene expression under normal (hydrated) and water stressed (dehydrated) conditions. After many generations in the lab, mice from the desert consumed significantly less water than mice from other localities, indicating that this difference has a genetic basis. Under water stress, desert mice lost less weight than non-desert mice, and desert mice exhibited differences in blood chemistry related to osmoregulatory function. Gene expression in the kidney revealed evolved differences between mice from different environments as well as plastic responses between hydrated and dehydrated mice. Desert mice showed reduced gene expression plasticity under water stress compared to non-desert mice. Importantly, the non-desert mice generally showed shifts towards desert-like expression under water stress, consistent with adaptive plasticity. Finally, patterns of gene expression identified several candidate genes for adaptation to the desert, including Aqp1 and Apoe. These findings provide evidence for local adaptation in a recently introduced species and suggest that adaptive plasticity may have facilitated the colonization of the desert environment.

THE CONDITION OF VOLUMETRIC AND OSMOREGULATORY FUNCTION OF THE KIDNEYS IN TOXICEMIA OF PURULENT-SEPTIC GENESIS IN PATIENTS WITH DIABETES MELLITUS

The aim of the study is to investigate the state of volumetric and osmoregulatory function of the kidneys in diabetes complicated by the syndrome of the endogenous intoxication of purulent-septic genesis. Materials and methods: The study group was consisted of patients with insulin-dependent diabetes mellitus with complicated syndrome of the endogenous intoxication of purulent-septic genesis (CSDI). Results: The starting indices of volumetric and osmoregulatory function of the kidneys in patients with INCs complicated by the endogenous intoxication of purulent-septic genesis (CEI GHG) syndrome are characterized by the values of the inhibition of the volumorregulatory (by the clearance of sodium by 11%, p <0.05) and the activation of the osmoregulatory osmotically active substances by 23%, p <0.05) renal function. The volume increasing of the extracellular space by the Ringer solution activates the volumetric and osmoregulatory function of the kidneys, respectively, in patients with NSCL at 162 ± 27.1% (Δ, p <0.05) and 138 ± 48.3% (Δ, p <0.05), and at INCS complicated CEE GHS by 260 ± 47.8% (Δ, p <0.05) and 147 ± 46.9% (Δ, p <0.05). Conclusions: The low-level isotonic loads with Ringer’s solution initiate the same direction of change in indices of volumetric and osmoregulatory function of the kidneys in patients with systemic inflammatory response syndrome and diabetes mellitus with complicated endogenous intoxication syndrome of purulent-septic genesis and show dissociative hyper reactivity of the volumorregulatory function in relation to the osmoregulatory one.

Monitoring of adaptive potential by functional loads and feeding regime of sturgeon juveniles

The article presents the results of research on the physiological and biochemical state of sturgeon juveniles using various functional loads at the early stages of post-embryonic development of sturgeon raised on an experimental diet in the presence of live food. The article analyzes the effectiveness of the application of functional load methods and feeding regimen to establish the physiological status of released juveniles to replenish natural populations. The article provides information about the stability of young sturgeon fish during the period of release from sturgeon hatcheries to replenish the natural population, further entry from fresh to sea water, and placement in places of natural feeding. The temperature and salinity of water for hydrobionts is a factor that has an integral effect on the activity of functionally important systems of the body at all stages of the life cycle. Juveniles obtained from artificial generations and grown in a combined way on various feeds retain high plasticity, adequate nutrition forms an osmoregulatory function and resistance to temperature conditions of the environment. It is proved experimentally that the feeding regime is an important factor affecting the fish-breeding and biological and physiological and biochemical parameters of young Russian sturgeon, stellate sturgeon and bester.