Thiamine deficiency can result in life-threatening physiological and neurological complications. While a thiamine-deficient diet may result in the onset of such symptoms, the presence of thiaminase - an enzyme that breaks down thiamine - is very often the cause. In such instances, thiaminase counteracts the bioavailability and uptake of thiamine, even when food-thiamine levels are adequate.
View Article and Find Full Text PDFDedicated conservation efforts spanning the past two decades have saved the Fennoscandian Arctic fox () population from local extinction, and extensive resources continue to be invested in the species' conservation and management. Although increasing, populations remain isolated, small and are not yet viable in the longer term. An understanding of causes of mortality are consequently important to optimize ongoing conservation actions.
View Article and Find Full Text PDFBackground: Germline mutations provide the raw material for all evolutionary processes and contribute to the occurrence of spontaneous human diseases and disorders. Yet despite the daily interaction of humans and other organisms with an increasing number of chemicals that are potentially mutagenic, precise measurements of chemically induced changes to the genome-wide rate and spectrum of germline mutation are lacking.
Objectives: A large-scale mutation-accumulation experiment was propagated in the presence and absence of an environmentally relevant cadmium concentration to quantify the influence of cadmium on germline mutation rates and spectra.
We lack a thorough understanding of the origin and maintenance of standing genetic variation that enables rapid evolutionary responses of natural populations. Whole genome sequencing of a resurrected Daphnia population shows that standing genetic variation in over 500 genes follows an evolutionary trajectory that parallels the pronounced and rapid adaptive evolution of multiple traits in response to predator-driven natural selection and its subsequent relaxation. Genetic variation carried by only five founding individuals from the regional genotype pool is shown to suffice at enabling the observed evolution.
View Article and Find Full Text PDFThe evolution of our understanding of the formation of thrombin from the postulated thrombokinase of Morawitz to activated Factor X and prothrombinase occurred during a period of nearly 100 years. During this time structure-function relationships have emerged and the roles of phospholipid surfaces, the accessory factor, Factor V and its activated form have been clarified. This paper summarizes this story with particular acknowledgement of the seminal contributions of Haskell Milstone.
View Article and Find Full Text PDFRelationships between different measures of stability are not well understood in part because empiricists and theoreticians tend to measure different aspects and most studies only explore a single form of stability. Using time-series data from experimental plankton communities, we compared temporal stability typically measured by empiricists (coefficient of variation in biomass) to stability measures typically measured by theoreticians derived from the community matrix (asymptotic resilience, initial resilience and intrinsic stochastic invariability) using first-order multivariate autoregressive models (MAR). Community matrices were also used to derive estimates of interaction strengths between plankton groups.
View Article and Find Full Text PDFCarrion represents an unpredictable and widely distributed primary food source for vultures and other avian scavengers. Avian scavengers in African savanna ecosystems are reported to rely exclusively on visual stimuli to locate carcasses. However, carnivores' predation of large mammalian herbivores and subsequent competition for access to the carcass can result in considerable noise, often audible over long distances and for prolonged periods.
View Article and Find Full Text PDFPurpose: The purpose of this review was to evaluate the factors that influence well-being, job satisfaction, stress, and burnout in speech-language pathologists (SLPs), and to identify the impact of these variables on worker recruitment and retention.
Method: A systematic literature search was conducted. Four electronic databases (PsycARTICLES & PsycINFO, PubMed/Medline, CINHAL and ABI/INFORM) were searched.
Health risk behaviours (HRBs) are prevalent within the cystic fibrosis (CF) population, and there is a lack of research around what influences their engagement. This research explored beliefs associated with HRBs within an adult CF population using qualitative semi-structured interviews. Participants' beliefs towards their CF and its life impact were investigated to explore reasons for engaging in HRB.
View Article and Find Full Text PDFThis study aimed to understand the movement behaviour and utilization distributions of Kori bustards in space and time in the Serengeti ecosystem. A total of 14 individuals were tracked with the aid of GPS (Geographical positioning system) satellite transmitters, and their sexes were identified using DNA analysis. A species utilization distribution was estimated using the Brownian bridge movement model (hereafter dBBMM) in which the probability of being in an area is conditioned by starting and ending (GPS) relocations.
View Article and Find Full Text PDFOver the past decade, significant advances have been made to unravel molecular mechanisms of stress response in different ecotoxicological model species. Within this study, we focus on population level transcriptomic responses of a natural population of Daphnia magna Straus, (1820), to heavy metals. We aim to characterize the population level transcriptomic responses, which include standing genetic variation, and improve our understanding on how populations respond to environmental stress at a molecular level.
View Article and Find Full Text PDFThe disappearance of an endangered African wild dog population from Serengeti National Park (SNP) led to international debate centered around one question: were researchers to blame? The "Burrows' hypothesis" postulated that stress induced by research-related immobilization and handling reactivated a latent rabies virus, eliminating the population. Insufficient data inhibited hypothesis testing, but since wild dogs persisted alongside SNP and have been studied since 2005, the hypothesis can be tested 25 years after its proposition. To be supported, wild dog immobilization interventions should have resulted in high mortality rates.
View Article and Find Full Text PDFThe Atlantic killifish (Fundulus heteroclitus), native to estuarine areas of the Atlantic coast of the United States, has become a valuable ecotoxicological model as a result of its ability to acclimate to rapid environmental changes and adapt to polluted habitats. MicroRNAs (miRNAs) are highly conserved small RNAs that regulate gene expression and play critical roles in stress responses in a variety of organisms. Global miRNA expression in killifish and the potential roles miRNA have in environmental acclimation have yet to be characterized.
View Article and Find Full Text PDFEnviron Sci Technol
August 2018
Toxicogenomic approaches can detect and classify adverse interactions between environmental toxicants and other environmental stressors but require more complex experimental designs and analytical approaches. Here we use novel toxicogenomic techniques to analyze the effect of arsenic exposure in wild killifish populations acclimating to changing salinity. Fish from three populations were acclimated to full strength seawater and transferred to fresh water for 1 or 24 h.
View Article and Find Full Text PDFInt J Offender Ther Comp Criminol
October 2018
Previous research has clearly demonstrated the positive impact of therapeutic interventions on offenders' well-being. Much less is known about the impact on prison staff facilitating and delivering such interventions. We employed qualitative methodology to capture a deeper understanding of the work of therapeutic prison officers.
View Article and Find Full Text PDFBackground: Regulatory adjustments to acute and chronic temperature changes are highly important for aquatic ectotherms because temperature affects their metabolic rate as well as the already low oxygen concentration in water, which can upset their energy balance. This also applies to severe changes in food supply. Thus, we studied on a molecular level (transcriptomics and/or proteomics) the immediate responses to heat stress and starvation and the acclimation to different temperatures in two clonal isolates of the model microcrustacean Daphnia pulex from more or less stressful environments, which showed a higher (clone M) or lower (clone G) tolerance to heat and starvation.
View Article and Find Full Text PDFMitochondrial DNA B Resour
May 2018
Here, we report the complete mitochondrial genome of the endangered Hine's emerald dragonfly (HED), Williamson. Data were generated via next generation sequencing (NGS) and assembled using a mitochondrial baiting and iterative mapping approach. The full length circular genome is 15,705 bp with 26.
View Article and Find Full Text PDF[This corrects the article DOI: 10.1093/conphys/cox067.][This corrects the article DOI: 10.
View Article and Find Full Text PDFJ Exp Zool A Ecol Integr Physiol
February 2017
Copy number variation (CNV) of genes coding for certain enzymes has been shown to be responsible for adaptation of arthropods to anthropogenic toxins. Natural toxins produced by cyanobacteria in freshwater ecosystems, that is, protease inhibitors (PIs), have been demonstrated to increase in frequency over the last decades due to eutrophication and global warming. These PIs inhibit digestive proteases of Daphnia, the major herbivore of phytoplankton and cyanobacteria.
View Article and Find Full Text PDFThe conservation of the African savanna elephant () is of prime importance for many African countries. Interactions between elephants and humans are known to induce stress and thereby have the potential to affect elephants' fitness. In Namibia, anthropogenic disturbances are increasing due to increasing human population size and development, particularly near protected areas, such as national parks.
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