Cardiovascular reactivity to acute psychological stress is associated with generalized self-efficacy and self-efficacy outcomes during adventure challenges.

Outdoor adventure challenges are commonly used to enhance self-efficacy, but the physiological mechanisms involved remain unexplored. Additionally, while studies have documented the influence of self-efficacy on stress management, general self-efficacy has yet to be fully understood in the context of cardiovascular stress reactivity (CVR). This study investigated the influence of self-efficacy beliefs on CVR during acute psychological stress tasks. Additionally, it explored whether CVR serves as a novel mechanism underlying the outcomes of outdoor adventure challenges. As part of a wider randomized controlled trial, participants (n = 55) were invited to complete a laboratory session to assess CVR to an active (paced auditory serial addition test (PASAT)) and a passive (cold pressor test (CPT)) stress task. Randomized participants (n = 33) to the experimental condition also engaged in a high ropes challenge course after the laboratory session. It was found that greater self-reported self-efficacy was associated with larger CVR during the CPT and positively associated with perceived engagement and performance during the PASAT. Secondly, participants reporting positive change in self-efficacy post-intervention were associated with greater CVR and greater CVR was associated with higher ratings of intervention engagement and perceived challenge. This study provides preliminary evidence suggesting that greater efficacy beliefs may heighten CVR to passive acute psychological stressors. Habitual stress reactivity may represent a novel mechanism involved in outdoor and adventure-based interventions. Future research should continue to explore the impact of psychological variables on stress physiology and examine CVR as a potential mechanism in adventure experiences.

Helicobacter pylori's historical journey through Siberia and the Americas.

The gastric bacterium Helicobacter pylori shares a coevolutionary history with humans that predates the out-of-Africa diaspora, and the geographical specificities of H. pylori populations reflect multiple well-known human migrations. We extensively sampled H. pylori from 16 ethnically diverse human populations across Siberia to help resolve whether ancient northern Eurasian populations persisted at high latitudes through the last glacial maximum and the relationships between present-day Siberians and Native Americans. A total of 556 strains were cultivated and genotyped by multilocus sequence typing, and 54 representative draft genomes were sequenced. The genetic diversity across Eurasia and the Americas was structured into three populations: hpAsia2, hpEastAsia, and hpNorthAsia. hpNorthAsia is closely related to the subpopulation hspIndigenousAmericas from Native Americans. Siberian bacteria were structured into five other subpopulations, two of which evolved through a divergence from hpAsia2 and hpNorthAsia, while three originated though Holocene admixture. The presence of both anciently diverged and recently admixed strains across Siberia support both Pleistocene persistence and Holocene recolonization. We also show that hspIndigenousAmericas is endemic in human populations across northern Eurasia. The evolutionary history of hspIndigenousAmericas was reconstructed using approximate Bayesian computation, which showed that it colonized the New World in a single migration event associated with a severe demographic bottleneck followed by low levels of recent admixture across the Bering Strait.

Hormesis depends upon the life-stage and duration of exposure: Examples for a pesticide and a nanomaterial.

Tests to assess toxic effects on the reproduction of adult C. elegans after 72h exposure for two chemicals, (3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)), also known as diuron, and silver nanoparticles (Ag NPs) indicated potential, although not significant hormesis. Follow up toxicity tests comparing the potential hormesis concentrations with controls at high replication confirmed that the stimulatory effect was repeatable and also statistically significant within the test. To understand the relevance of the hormesis effects for overall population fitness, full life-cycle toxicity tests were conducted for each chemical. When nematodes were exposed to DCMU over the full life-span, the hormesis effect for reproduction seen in short-term tests was no longer evident. Further at the putative hormesis concentrations, a negative effect of DCMU on time to maturation was also seen. For the Ag NPs, the EC50 for effects on reproduction in the life-cycle exposure was substantially lower than in the short-term test, the EC50s estimated by a three parameter log logistic model being 2.9mg/L and 0.75mg/L, respectively. This suggests that the level of toxicity for Ag NPs for C. elegans reproduction is dependant on the life stage exposed and possibly the duration of the exposure. Further, in the longer duration exposures, hormesis effects on reproduction seen in the short-term exposures were no longer apparent. Instead, all concentrations reduced both overall brood size and life-span. These results for both chemicals suggest that the hormesis observed for a single endpoint in short-term exposure may be the result of a temporary reallocation of resources between traits that are not sustained over the full life-time. Such reallocation is consistent with energy budget theories for organisms subject to toxic stress.

Analytical approaches to support current understanding of exposure, uptake and distributions of engineered nanoparticles by aquatic and terrestrial organisms.

Initiatives to support the sustainable development of the nanotechnology sector have led to rapid growth in research on the environmental fate, hazards and risk of engineered nanoparticles (ENP). As the field has matured over the last 10 years, a detailed picture of the best methods to track potential forms of exposure, their uptake routes and best methods to identify and track internal fate and distributions following assimilation into organisms has begun to emerge. Here we summarise the current state of the field, focussing particularly on metal and metal oxide ENPs. Studies to date have shown that ENPs undergo a range of physical and chemical transformations in the environment to the extent that exposures to pristine well dispersed materials will occur only rarely in nature. Methods to track assimilation and internal distributions must, therefore, be capable of detecting these modified forms. The uptake mechanisms involved in ENP assimilation may include a range of trans-cellular trafficking and distribution pathways, which can be followed by passage to intracellular compartments. To trace toxicokinetics and distributions, analytical and imaging approaches are available to determine rates, states and forms. When used hierarchically, these tools can map ENP distributions to specific target organs, cell types and organelles, such as endosomes, caveolae and lysosomes and assess speciation states. The first decade of ENP ecotoxicology research, thus, points to an emerging paradigm where exposure is to transformed materials transported into tissues and cells via passive and active pathways within which they can be assimilated and therein identified using a tiered analytical and imaging approach.

Effects of outdoor recreational physical challenges on general self-efficacy: A randomized controlled trial.

Outdoor programs involving recreational physical challenges are becoming increasingly popular for training and development purposes among adults, but rigorous studies investigating their effectiveness remain scarce. A randomized controlled trial was conducted to evaluate the effects of an outdoor adventure-based program on measures of self-efficacy, resilience, risk-taking propensity, and perceived stress. Participants were randomly assigned either to an intervention condition (half-day high ropes course) or a wait-list control group. Measures were taken at baseline and four days post-intervention and on the day to measure intervention perceptions. Significant increases in self-efficacy and risk-taking propensity were observed for the intervention arm compared to the control arm. Greater intervention engagement and affective valence ratings were associated with self-efficacy change. These findings highlight the practical relevance of adventure-based experiences for organizations and educational institutions seeking to enhance young adults' self-confidence. Additionally, they emphasize the importance of tailoring interventions to individual needs and ensuring positive participant experiences to achieve desired outcomes.

Genomic diversity of Salmonella enterica -The UoWUCC 10K genomes project.

Background: Most publicly available genomes of Salmonella enterica are from human disease in the US and the UK, or from domesticated animals in the US. Methods: Here we describe a historical collection of 10,000 strains isolated between 1891-2010 in 73 different countries. They encompass a broad range of sources, ranging from rivers through reptiles to the diversity of all S. enterica isolated on the island of Ireland between 2000 and 2005. Genomic DNA was isolated, and sequenced by Illumina short read sequencing. Results: The short reads are publicly available in the Short Reads Archive. They were also uploaded to EnteroBase, which assembled and annotated draft genomes. 9769 draft genomes which passed quality control were genotyped with multiple levels of multilocus sequence typing, and used to predict serovars. Genomes were assigned to hierarchical clusters on the basis of numbers of pair-wise allelic differences in core genes, which were mapped to genetic Lineages within phylogenetic trees. Conclusions: The University of Warwick/University College Cork (UoWUCC) project greatly extends the geographic sources, dates and core genomic diversity of publicly available S. enterica genomes. We illustrate these features by an overview of core genomic Lineages within 33,000 publicly available Salmonella genomes whose strains were isolated before 2011. We also present detailed examinations of HC400, HC900 and HC2000 hierarchical clusters within exemplar Lineages, including serovars Typhimurium, Enteritidis and Mbandaka. These analyses confirm the polyphyletic nature of multiple serovars while showing that discrete clusters with geographical specificity can be reliably recognized by hierarchical clustering approaches. The results also demonstrate that the genomes sequenced here provide an important counterbalance to the sampling bias which is so dominant in current genomic sequencing.

Phenotypic responses in Caenorhabditis elegans following chronic low-level exposures to inorganic and organic compounds.

Responses of organisms to sublethal exposure of environmental stressors can be difficult to detect. We investigated phenotypic changes in the tissue of Caenorhabditis elegans via Raman spectroscopy, as well as survival and reproductive output when exposed to chronic low doses of metals (copper, zinc, or silver), an herbicide (diuron), and a pesticide (imidacloprid). Raman spectroscopy measures changes in phenotype by providing information about the molecular composition and relative abundance of biomolecules. Multivariate analysis was used to evaluate the significance of treatment phenotype segregation plots compared with controls. Dose-dependent responses were observed for copper, zinc, silver, and diuron, whereas imidacloprid exposure resulted in a small response over the tested concentrations. Concentration-dependent shifts in nematode biomolecular phenotype were observed for copper. Despite having a dose-dependent reproductive response, silver, diuron, and imidacloprid produced inconsistent biological phenotype patterns. In contrast, there was a clear stepwise change between low concentrations (0.00625-0.5 mg/L) and higher concentration (1-2 mg/L) of ionic zinc. The findings demonstrate that measuring phenotypic responses via Raman spectroscopy can provide insights into the biomolecular mechanisms of toxicity. Despite the lack of consistency between survival and Raman-measured phenotypic changes, the results support the effectiveness of Raman spectroscopy and multivariate analysis to detect sublethal responses of chemicals in whole organisms and to identify toxic effect thresholds. Environ Toxicol Chem 2018;37:920-930. © 2017 SETAC.

A new medium for Caenorhabditis elegans toxicology and nanotoxicology studies designed to better reflect natural soil solution conditions.

A new toxicity test medium for Caenorhabditis elegans is presented. The test solution is designed to provide a better representation of natural soil pore water conditions than currently available test media. The medium has a composition that can readily be modified to allow for studies of the influences of a range of environmentally relevant parameters on nematode biology and toxicology. Tests conducted in the new medium confirmed that nematodes' reproduction was possible at a range of solution pH levels, offering the potential to conduct toxicity studies under a variety of conditions. A test to establish silver nanoparticle and dissolved silver nitrate toxicity, a study type not feasible in M9 or agar media due to precipitation and nanoparticle agglomeration, indicated lower silver nanoparticle (median effective concentration [EC50] of 6.5 mg Ag/L) than silver nitrate (EC50 0.28 mg Ag/L) toxicity. Characterization identified stable nanoparticle behavior in the new test medium.

Genetically variable nucleopolyhedroviruses isolated from spatially separate populations of the winter moth Operophtera brumata (Lepidoptera: Geometridae) in Orkney.

Here we report a lepidopteran system in which a pathogen is both abundant and genotypically variable. Geographically separate populations of winter moth (Operophtera brumata L.) were sampled in heather habitats on the Orkney Isles to investigate the prevalence of a pathogen, O. brumata Nucleopolyhedrovirus (OpbuNPV), within the natural system. Virus was recorded in 11 of the 13 winter moth populations sampled, with two populations suffering mortality due to virus at levels of 50%. The virus genome from 200 single insect isolations was investigated for variation using restriction endonuclease digests. Twenty-six variants of OpbuNPV were detected using SalI. The polyhedrin gene of the virus was partially sequenced, allowing the relationship between the 26 variants to be portrayed as a cladogram. The phylogenetic relationship between OpbuNPV and other known baculovirus polyhedrin gene sequences was also established. The discovery of virus at such high prevalence is discussed with reference to occurrence and genetic variation of pathogens in other lepidopteran host populations. This study shows encouraging results for further studies into the role of pathogens in the regulation of host insect populations.