Africanization of a feral honey bee (Apis mellifera) population in South Texas: does a decade make a difference?

The arrival to the United States of the Africanized honey bee, a hybrid between European subspecies and the African subspecies Apis mellifera scutellata, is a remarkable model for the study of biological invasions. This immigration has created an opportunity to study the dynamics of secondary contact of honey bee subspecies from African and European lineages in a feral population in South Texas. An 11‐year survey of this population (1991–2001) showed that mitochondrial haplotype frequencies changed drastically over time from a resident population of eastern and western European maternal ancestry, to a population dominated by the African haplotype. A subsequent study of the nuclear genome showed that the Africanization process included bidirectional gene flow between European and Africanized honey bees, giving rise to a new panmictic mixture of A. m. scutellata‐ and European‐derived genes. In this study, we examined gene flow patterns in the same population 23 years after the first hybridization event occurred. We found 28 active colonies inhabiting 92 tree cavities surveyed in a 5.14 km² area, resulting in a colony density of 5.4 colonies/km². Of these 28 colonies, 25 were of A. m. scutellata maternal ancestry, and three were of western European maternal ancestry. No colonies of eastern European maternal ancestry were detected, although they were present in the earlier samples. Nuclear DNA revealed little change in the introgression of A. m. scutellata‐derived genes into the population compared to previous surveys. Our results suggest this feral population remains an admixed swarm with continued low levels of European ancestry and a greater presence of African‐derived mitochondrial genetic composition.     

Network Analysis of Metabolite GWAS Hits: Implication of CPS1 and the Urea Cycle in Weight Maintenance

Background and Scope

Weight loss success is dependent on the ability to refrain from regaining the lost weight in time. This feature was shown to be largely variable among individuals, and these differences, with their underlying molecular processes, are diverse and not completely elucidated. Altered plasma metabolites concentration could partly explain weight loss maintenance mechanisms. In the present work, a systems biology approach has been applied to investigate the potential mechanisms involved in weight loss maintenance within the Diogenes weight-loss intervention study.

Methods and Results

A genome wide association study identified SNPs associated with plasma glycine levels within the CPS1 (Carbamoyl-Phosphate Synthase 1) gene (rs10206976, p-value = 4.709e-11 and rs12613336, p-value = 1.368e-08). Furthermore, gene expression in the adipose tissue showed that CPS1 expression levels were associated with successful weight maintenance and with several SNPs within CPS1 (cis-eQTL). In order to contextualize these results, a gene-metabolite interaction network of CPS1 and glycine has been built and analyzed, showing functional enrichment in genes involved in lipid metabolism and one carbon pool by folate pathways.

Conclusions

CPS1 is the rate-limiting enzyme for the urea cycle, catalyzing carbamoyl phosphate from ammonia and bicarbonate in the mitochondria. Glycine and CPS1 are connected through the one-carbon pool by the folate pathway and the urea cycle. Furthermore, glycine could be linked to metabolic health and insulin sensitivity through the betaine osmolyte. These considerations, and the results from the present study, highlight a possible role of CPS1 and related pathways in weight loss maintenance, suggesting that it might be partly genetically determined in humans.     

Development and Two-Year Follow-Up Evaluation of a Training Workshop for the Large Preventive Positive Psychology Happy Family Kitchen Project in Hong Kong

Evidence-based practice and capacity-building approaches are essential for large-scale health promotion interventions. However, there are few models in the literature to guide and evaluate training of social service workers in community settings. This paper presents the development and evaluation of the “train-the-trainer” workshop (TTT) for the first large scale, community-based, family intervention projects, entitled “Happy Family Kitchen Project” (HFK) under the FAMILY project, a Hong Kong Jockey Club Initiative for a Harmonious Society. The workshop aimed to enhance social workers’ competence and performance in applying positive psychology constructs in their family interventions under HFK to improve family well-being of the community they served. The two-day TTT was developed and implemented by a multidisciplinary team in partnership with community agencies to 50 social workers (64% women). It focused on the enhancement of knowledge, attitude, and practice of five specific positive psychology themes, which were the basis for the subsequent development of the 23 family interventions for 1419 participants. Acceptability and applicability were enhanced by completing a needs assessment prior to the training. The TTT was evaluated by trainees’ reactions to the training content and design, changes in learners (trainees) and benefits to the service organizations. Focus group interviews to evaluate the workshop at three months after the training, and questionnaire survey at pre-training, immediately after, six months, one year and two years after training were conducted. There were statistically significant increases with large to moderate effect size in perceived knowledge, self-efficacy and practice after training, which sustained to 2-year follow-up. Furthermore, there were statistically significant improvements in family communication and well-being of the participants in the HFK interventions they implemented after training. This paper offers a practical example of development, implementation and model-based evaluation of training programs, which may be helpful to others seeking to develop such programs in diverse communities.     

Visuospatial Attention to Single and Multiple Objects Is Independently Impaired in Parkinson's Disease

Parkinson’s disease (PD) is associated with deficits in visuospatial attention. It is as yet unknown whether these attentional deficits begin at a perceptual level or instead reflect disruptions in oculomotor or higher-order processes. In the present study, non-demented individuals with PD and matched normal control adults (NC) participated in two tasks requiring sustained visuospatial attention, both based on a multiple object tracking paradigm. Eye tracking was used to ensure central fixation. In Experiment 1 (26 PD, 21 NC), a pair of identical red dots (one target, one distractor) rotated randomly for three seconds at varied speeds. The task was to maintain the identity of the sole target, which was labeled prior to each trial. PD were less accurate than NC overall (p = .049). When considering only trials where fixation was maintained, however, there was no significant group difference, suggesting that the deficit’s origin is closely related to oculomotor processing. To determine whether PD had additional impairment in multifocal attention, in Experiment 2 (25 PD, 15 NC), two targets were presented along with distractors at a moderate speed, along with a control condition in which dots remained stationary. PD were less accurate than NC for moving (p = 0.02) but not stationary targets. This group difference remained significant when considering only trials where fixation was maintained, suggesting the source of the PD deficit was independent from oculomotor processing. Taken together, the results implicate separate mechanisms for single vs. multiple object tracking deficits in PD.     

How accessible are coral reefs to people? A global assessment based on travel time

The depletion of natural resources has become a major issue in many parts of the world, with the most accessible resources being most at risk. In the terrestrial realm, resource depletion has classically been related to accessibility through road networks. In contrast, in the marine realm, the impact on living resources is often framed into the Malthusian theory of human density around ecosystems. Here, we develop a new framework to estimate the accessibility of global coral reefs using potential travel time from the nearest human settlement or market. We show that 58% of coral reefs are located < 30 min from the nearest human settlement. We use a case study from New Caledonia to demonstrate that travel time from the market is a strong predictor of fish biomass on coral reefs. We also highlight a relative deficit of protection on coral reef areas near people, with disproportional protection on reefs far from people. This suggests that conservation efforts are targeting low‐conflict reefs or places that may already be receiving de facto protection due to their isolation. Our global assessment of accessibility in the marine realm is a critical step to better understand the interplay between humans and resources.     

Fragile X‐associated tremor/ataxia syndrome: Regional decrease of mitochondrial DNA copy number relates to clinical manifestations

Fragile X‐associated tremor/ataxia syndrome (FXTAS) is a late‐onset neurodegenerative disorder that appears in at least one‐third of adult carriers of a premutation (55‐200 CGG repeats) in the fragile X mental retardation 1 (FMR1) gene. Several studies have shown that mitochondrial dysfunction may play a central role in aging and also in neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease as well as in FXTAS. It has been recently proposed that mtDNA copy number, measured by the number of mitochondrial genomes per nuclear genome (diploid), could be a useful biomarker of mitochondrial dysfunction. In order to elucidate the role of mtDNA variation in the pathogenesis of FXTAS, mtDNA copy number was quantified by digital droplet Polymerase chain reaction. In human brain samples, mtDNA levels were measured in the cerebellar vermis, dentate nucleus, parietal and temporal cortex, thalamus, caudate nucleus and hippocampus from a female FXTAS patient, a FMR1 premutation male carrier without FXTAS and from three male controls. The mtDNA copy number was further analyzed using this technology in dermal fibroblasts primary cultures derived from three FXTAS patients and three controls as well as in cortex and cerebellum of a CGG knock in FXTAS mice model. Finally, qPCR was carried out in human blood samples. Results indicate reduced mtDNA copy number in the specific brain region associated with disease progression in FXTAS patients, providing new insights into the role of mitochondrial dysfunction in the pathogenesis of FXTAS.     

Paediatric brain tissue properties measured with magnetic resonance elastography

Biomechanics and Modeling in Mechanobiology - The aim of this study is to characterise the stiffness of white and grey matter in paediatric subjects using magnetic resonance elastography (MRE) and...     

Chelate-assisted phytoextraction of lead using Fagopyrum esculentum: laboratory vs. field experiments

Abstract

The development of more sustainable remediation techniques has been receiving greater attention, as an alternative to soil excavation plan in urban gardens. An in situ phytoextraction experiment with buckwheat (Fagopyrum esculentum) was performed with a 5?mmol kg^?1 citric acid (CA) application. Joint experiments under laboratory conditions were conducted using various cultivars of F. esculentum in two soils with a Pb contamination of either geogenic or anthropogenic origin and various chelate concentrations. Results show that a minimum dose of 50?mmol kg^?1 of CA is required to lower soil pH and raise the concentration of mobile Pb–CaCl₂ for both soils. Consequently, Pb shoot uptake is increased from 6.3 to 8.9 times depending on soil type. Phytoextraction efficiency is found to be 1.3 to 2.0 times higher in the anthropogenic contaminated soil than in the soil with geogenic Pb. A scale effect has also been identified since Pb root accumulation under laboratory conditions was 2.4 times higher than in the field experiment. Despite an increase in the Pb extraction rate with CA, buckwheat appears to lack the efficiency needed to remove Pb in moderately contaminated soils. The calculated remediation period would last 166?years to remove the mobile Pb fraction.