From soil to cacao bean: Unravelling the pathways of cadmium translocation in a high Cd accumulating cultivar of Theobroma cacao L.

The research on strategies to reduce cadmium (Cd) accumulation in cacao beans is currently limited by a lack of understanding of the Cd transfer pathways within the cacao tree. Here, we elucidated the transfer of Cd from soil to the nib (seed) in a high Cd accumulating cacao cultivar. Here, we elucidated the transfer of Cd from soil to the nib (seed) in a high Cd accumulating cacao cultivar through Cd stable isotope fractionation, speciation (X-Ray Absorption Spectroscopy), and localization (Laser Ablation Inductively Coupled Plasma Mass Spectrometry). The plant Cd concentrations were 10-28 higher than the topsoil Cd concentrations and increased as placenta< nib< testa< pod husk< root< leaf< branch. The retention of Cd in the roots was low. Light Cd isotopes were retained in the roots whilst heavier Cd isotopes were transported to the shoots (Δ 114/110 Cd shoot-root = 0.27 ± 0.02 ‰ (weighted average ± standard deviation)). Leaf Cd isotopes were heavier than Cd in the branches (Δ 114/110 Cd IF3 leaves-branch = 0.18 ± 0.01 ‰), confirming typical trends observed in annual crops. Nibs and branches were statistically not distinguishable (Δ 114/110 Cd nib-branch = -0.08‰ ± 0.06 ‰), contrary to the leaves and nibs (Δ 114/110 Cd nib-IF3 leaves = -0.25‰ ± 0.05 ‰). These isotope fractionation patterns alluded to a more direct transfer from branches to nibs rather than from leaves to nibs. The largest fraction (57%) of total plant Cd was present in the branches where it was primarily bound to carboxyl-ligands (60-100%) and mainly localized in the phloem rays and phelloderm of the bark. Cadmium in the nibs was mainly bound to oxygen ligands (60-90%), with phytate as the most plausible ligand. The weight of evidence suggested that Cd was transferred like other nutrients from root to shoot and accumulated in the phloem rays and phelloderm of the branches to reduce the transfer to foliage. Finally, the data indicated that the main contribution of nib Cd was from the phloem tissues of the branch rather than from leaf remobilization. This study extended the limited knowledge on Cd accumulation in perennial, woody crops and revealed that the Cd pathways in cacao are markedly different than in annual crops.

Posture and Muscle Activity during Waste Collection Work.

The musculoskeletal load in waste collection has been examined through simulated assessment of pulling and pushing bins as well as lifting and throwing rubbish bags. With the onset of mechanization, many of these tasks do not exist and workers are faced with other loads not previously assessed. The purpose of this study was to quantify the postures and muscle activity during mechanized waste collection work. Three subtasks of mechanized waste collection were identified, namely driving, bin collection, and egress and access of the vehicle. Spinal, shoulder, and upper limb kinematics along with surface electromyography from three muscles were collected during these tasks in a typical work shift. During driving and bin collection, participants adopted a head-extended, torso forward-flexed posture with frequent rotations of the head and neck. Egress and access of the vehicle produced substantially larger ranges of movement compared with driving and bin collection. The forward-flex, sitting posture can increase the risk of low back pain if there are undulations in the terrain and if this posture is adopted for prolonged periods. The frequent head and neck rotations can increase the incidence and severity of neck pain. Prolonged driving has been linked with an increased cardiometabolic risk and egress and access has increased risk of trips and falls from a height. Managers of waste collection workers should consider implementing interventions to reduce the exposure of this important workforce to the deleterious demands of their work.

Plant metal concentrations in Theobroma cacao as affected by soil metal availability in different soil types.

Beans of cacao (Theobroma cacaoL.) are used to produce a variety of chocolate products. Bioaccumulation of metals at toxic levels through the consumption of contaminated products has been identified as a health concern in humans. Both metal diversity and concentration as well as their interactions in the soil influence essential and non-essential metal uptake in plants; but the effects of these on bioaccumulation of metals in cacao is not understood across diverse soil types. In this study eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were investigated in 12 soil subgroups belonging to four soil orders across 15 locations in Trinidad, with the aim to investigate the effect of soil metal diversity and concentration on metal bioaccumulation in cacao. Soil metals were extracted using five methods (aqua regia, DTPA, Mehlich 3, nitric acid, and water). Cacao leaf metal concentrations were determined using the USEPA 3052 method. Metal extraction efficiency ranged between methods with aqua regia ≥ nitric acid > Mehlich 3 ≥ DTPA ≥ water across all metals. The soil extraction method that best predicted cacao leaf metal concentrations varied with the metal - Mehlich 3 or DTPA for Cd, Ni, Zn; aqua regia, Mehlich 3, or nitric acid for Pb, and water for Mn. A stepwise regression analysis showed that plant metal concentration can be predicted using soil physicochemical characteristics as well as the concentration of metals in the soil. The importance of soil type on cacao leaf metal bioaccumulation is discussed.

Genetic variation in bioaccumulation and partitioning of cadmium in Theobroma cacao L.

Cadmium (Cd) is a non-essential heavy metal that is toxic to both plants and animals and chocolates have been identified as a contributor to the human dietary Cd intake. One hundred accessions representing the various genetic groups and hybrid populations in Theobroma cacao L. held at the International Cocoa Genebank, Trinidad were evaluated for leaf and bean cadmium levels with three tree replications. Representative samples of soil from the drip zone around each tree were evaluated for bioavailable cadmium. Although there were significant differences (P ≤ 0.05) among genetic groups for leaf and bean Cd much of the variation was between accessions. There was a 13-fold variation in bean Cd and a 7-fold variation in leaf Cd between accessions despite the bioavailable Cd in the soil being uniform. There were differences in the level of partitioning into beans evident by significant variation (P ≤ 0.05) in bean Cd as a percentage of the cumulative leaf and bean Cd concentration (15-52%) between accessions. Although in general there was a higher concentration of cadmium in the testa than the cotyledon of the cocoa bean there was considerable genetic variation. These results point to the potential of using a genetic strategy to mitigate cadmium within cocoa beans either through breeding or through the use of low cadmium uptake rootstocks in grafting. The results will fuel further work into the understanding of mechanisms and genetics of cadmium uptake and partitioning in cocoa.

Re-sensitizing Multidrug Resistant Bacteria to Antibiotics by Targeting Bacterial Response Regulators: Characterization and Comparison of Interactions between 2-Aminoimidazoles and the Response Regulators BfmR from Acinetobacter baumannii and QseB from Francisella spp.

2-aminoimidazole (2-AI) compounds inhibit the formation of bacterial biofilms, disperse preformed biofilms, and re-sensitize multidrug resistant bacteria to antibiotics. 2-AIs have previously been shown to interact with bacterial response regulators, but the mechanism of interaction is still unknown. Response regulators are one part of two-component systems (TCS). TCSs allow cells to respond to changes in their environment, and are used to trigger quorum sensing, virulence factors, and antibiotic resistance. Drugs that target the TCS signaling process can inhibit pathogenic behavior, making this a potent new therapeutic approach that has not yet been fully exploited. We previously laid the groundwork for the interaction of the Acinetobacter baumannii response regulator BfmR with an early 2-AI derivative. Here, we further investigate the response regulator/2-AI interaction and look at a wider library of 2-AI compounds. By combining molecular modeling with biochemical and cellular studies, we expand on a potential mechanism for interaction between response regulators and 2-AIs. We also establish that Francisella tularensis/novicida, encoding for only three known response regulators, can be a model system to study the interaction between 2-AIs and response regulators. We show that knowledge gained from studying Francisella can be applied to the more complex A. baumannii system, which contains over 50 response regulators. Understanding the impact of 2-AIs on response regulators and their mechanism of interaction will lead to the development of more potent compounds that will serve as adjuvant therapies to broad-range antibiotics.

Using Community Advisory Boards to Build Partnerships and Develop Peer-Led Services for Rural Student Veterans.

BACKGROUND: The Department of Veterans' Affairs (VA)/Student Partnership for Rural Veterans (VSP) built partnerships between institutional (health services researchers, VA chaplains) and community groups to develop veteran-to-veteran services on college campuses. OBJECTIVES: Describe challenges and lessons learned in year 1 of the VSP project at six campuses in rural Arkansas. METHODS: Researchers leveraged established community advisory boards (CABs) to develop veteran-to-veteran services. Ethnographic and qualitative methods were used to assess partnership building and evaluate peer-led services. RESULTS: Local established CABs and buy-in from student services and veteran organizations was instrumental to building partnerships and developing services. Challenges included developing rapport with campus leaders and creating sustainable role/expectations for student veteran leaders. CONCLUSIONS: Peer-led services are an ideal way to connect student veterans and link them to resources and health care services. Partnerships can facilitate grassroots efforts to develop local services that meet the needs of diverse student veteran populations.

Building partnerships with rural Arkansas faith communities to promote veterans' mental health: lessons learned.

BACKGROUND: The Mental Health-Clergy Partnership Program established partnerships between institutional (Department of Veterans' Affairs [VA] chaplains, mental health providers) and community (local clergy, parishioners) groups to develop programs to assist rural veterans with mental health needs. OBJECTIVES: Describe the development, challenges, and lessons learned from the Mental Health-Clergy Partnership Program in three Arkansas towns between 2009 and 2012. METHODS: Researchers identified three rural Arkansas sites, established local advisory boards, and obtained quantitative ratings of the extent to which partnerships were participatory. RESULTS: Partnerships seemed to become more participatory over time. Each site developed distinctive programs with variation in fidelity to original program goals. Challenges included developing trust and maintaining racial diversity in local program leadership. CONCLUSIONS: Academics can partner with local faith communities to create unique programs that benefit the mental health of returning veterans. Research is needed to determine the effectiveness of community based programs, especially relative to typical "top-down" outreach approaches.