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A trophic niche shift can occur as an adaptive response to environmental change such as altered resource quality, abundance or composition. Alterations in digestive traits such as gut morphology and physiology may enable these niche shifts and affect the persistence of populations and species. Relatively few studies, however, have assessed how niche shifts influence suites of digestive traits through phenotypic plasticity and evolutionary mechanisms, and how these trait changes can subsequently alter the nutrition, fitness and life history of organisms. We investigated how population divergence and plasticity alter the gut physiology of wild Trinidadian guppies (Poecilia reticulata), assessing whether variation in digestive traits correspond with enhanced nutrient assimilation under a pronounced dietary shift. We examined gut enzyme activity, and gut size and mass of wild guppies from both high-predation (HP) and low-predation (LP) habitats when reared in the laboratory and fed on high- or low-quality diets designed to reflect their dietary differences previously found in nature. After 10weeks on the experimental diets, HP guppies maintained shorter and lighter guts than LP guppies on either diet. Guppies also differed in their digestive enzymatic profiles, more often reflecting nutrient balancing so that increased enzyme expression tended to correspond with more deficient nutrients in the diet. LP guppies had increased somatic phosphorus at the end of the experiment, possibly related to the higher alkaline phosphatase activity in their guts. Our results suggest that differences in gut physiology exist among populations of Trinidadian guppies that may reflect local adaptation to their disparate environments.

This study used a damaged skin, porcine model to evaluate the in vivo efficacy of WoundStat™ for the decontamination of superficial, nerve agent-contaminated wounds. Anaesthetized animals were randomly assigned to either control (n = 7), no decontamination (n = 12) or WoundStat™ (n = 12) treatment groups. Pigs were exposed to a 5× LD50 dose of neat, radiolabelled S-[2- (diisopropylamino)ethyl]-O-ethyl methyl-phosphonothioate (VX; or equivalent volume of sterile saline for the control group) via an area of superficially damaged skin on the ear. WoundStat™ was applied at 30 seconds post-exposure to assigned animals. The VX contaminant (or saline) and decontaminant remained in place for the duration of the study (up to 6 hours). Physiological parameters and signs of intoxication were recorded during the exposure period. Skin and organ samples were taken post mortem for 14C–VX distribution analyses. Blood samples were taken periodically for toxicokinetic and whole-blood acetylcholinesterase (AChE) activity analyses. VX exposure was accompanied by a rapid decrease in AChE activity in all animals, regardless of decontamination. However, decontamination significantly improved survival rate and time and reduced the severity of signs of intoxication. In addition, the distribution of 14C–VX in key internal organs and post mortem blood samples was significantly lower in the WoundStat™ treatment group. This study demonstrates that WoundStat™ may be a suitable medical countermeasure for increasing both survival rate and time following VX exposure. The results also suggest that AChE activity is not a useful prognostic indicator.

Background: Declines in gait velocity, stride length, cadence, and postural stability are common with advancing age and have further been linked to heightened fall risk and functional decline. Physical activity can slow or prevent such gait declines in older adults. In young adults, Nordic walking (NW) training has been shown to increase stride length and gait speed, yet has demonstrated inconsistent findings regarding joint loading, with reports of both increases and decreases in this respect. Further, research of this facet has very minimally been examined as it pertains to older adults. Purpose: The aim of the present study was to determine both the initial effect, and the prolonged effect following an 8-week intervention, of Nordic walking (NW) on older adult gait performance and postural alignment and stability. Methods: Gait and postural alignment and stability during NW and conventional walking were assessed and compared following an 8-week NW program (2x/week) in 12 healthy older adults (age: 68 ± 6.8 years; 8 female, 4 male). Participants performed six 5m walking trials, 3 with poles and 3 without, followed by two 6 Minute Walk Test (6MWT) trials, one with poles (WP) and the other without (NP). Gait characteristics and trunk measures in the sagittal and frontal planes were quantified using a 6 inertial sensor accelerometry system (APDM, Oregon, USA) as well as an eight camera 3-dimensional motion capture system (Vicon, Oxford, UK) with 2 force platforms (Kistler, Winterthur, Switzerland) embedded within. All variables were assessed using two-way repeated measures ANOVAs to compare NW to conventional walking and before and after the intervention. Results: When comparing walking WP to NP at initial pre-testing, significantly longer stride length, slower gait speed, and increased double support time were found to coincide with decreases in power generation and absorption at the hip and knee WP. However, following prolonged practice, a longer stride length, faster gait speed, and increased power generation at pre-swing at the hip and power absorption during loading and terminal swing about the knee were found WP post-intervention. Conclusions: An initial 8-week training period is necessary for novice NW in order to develop technique and to restore gait and postural alignment to more “normal” standards following training. Additionally, since the acquisition of the skill requires proper allocation of attention between two tasks: walking and pole manipulation, NW should be done so in a relatively safe environment, free of distraction and obstacles. Finally, with frail elderly, a longer acquisition period may be necessary since facilitation of movement must first occur.

Human-induced trait change has been documented in freshwater, marine, and terrestrial ecosystems worldwide. These trait changes are driven by phenotypic plasticity and contemporary evolution. While efforts to manage human-induced trait change are beginning to receive some attention, managing its ecological consequences has received virtually none. Recent work suggests that contemporary trait change can have important effects on the dynamics of populations, communities, and ecosystems. Therefore, trait changes caused by human activity may be shaping ecological dynamics on a global scale. We present evidence for important ecological effects associated with human-induced trait change in a variety of study systems. These effects can occur over large spatial scales and impact system-wide processes such as trophic cascades. Importantly, the magnitude of these effects can be on par with those of traditional ecological drivers such as species presence. However, phenotypic change is not always an agent of ecological change; it can also buffer ecosystems against change. Determining the conditions under which phenotypic change may promote vs prevent ecological change should be a top research priority.