Modulating the catalytic activity of enzyme-like nanoparticles through their surface functionalization

The inclusion of transition metal catalysts into nanoparticle scaffolds permits the creation of catalytic nanosystems (nanozymes) able to imitate the behaviour of natural enzymes. Here we report the fabrication of a family of nanozymes comprised of bioorthogonal ruthenium catalysts inserted in the protective monolayer of gold nanoparticles. By introducing simple modifications to the functional groups at the surface of the nanozymes, we have demonstrated control over the kinetic mechanism of our system. Cationic nanozymes with hydrophobic surface functionalities tend to replicate the classical Michaelis Menten model, while those with polar groups display substrate inhibition behaviour, a key mechanism present in 20% of natural enzymes. The structural parameters described herein can be used for creating artificial nanosystems that mimic the complexity observed in cell machinery. © 2018 The Royal Society of Chemistry

Determination of some heavy metals in soil and edible vegetables grown in two different farms in Damaturu Metropolis, Yobe State, Nigeria

Vegetables comprise an important part of our daily foods that contribute some minerals and other nutrients to human body. Consumption of contaminated vegetables by heavy metals results in bioaccumulation of these harmful elements in the body. Therefore, this study is designed to examine the amount of heavy metal concentrations (Nickel, Copper, Cadmium and Zinc) in soil and edible parts of four vegetables namely Amaranthus hybridus (spinach), Hibiscus sabdariffa (roselle), Urena lobata (caesar weed) and Ceratotheca sesamoides (false sesame) grown in two farms. Transfer factor of heavy metals from soil to the plants was also evaluated. Samples were prepared and analysed using Atomic Absorption Spectrophotometry (AAS). The mean concentrations of all the vegetables in the both farms for Ni, Cu, Cd and Zn were obtained as 0.215, 2.341, 0.023 and 2.251 mg/Kg respectively. Whereas, the mean concentrations in the soils were 0.317, 7.560, 0.071 and 9.910 mg/Kg for Ni, Cu, Cd and Zn respectively. The levels of the above heavy metals in almost all the samples from those farms were below the maximum allowable limits recommended by WHO/FAO and therefore, they had acceptable conditions for human consumption. The exception was Ni which was slightly above the (0.1 mg/Kg) WHO/FAO permissible limit in the samples of both farms excluding Urena lobata of Custom Farm. In Bin Bukar, the trend of the transfer factor was in rank of Ni > Cd > Cu > Zn, whereas, in Custom Farm the transfer factor was sort as Cu > Ni > Cd. The highest Transfer Factor (TF) value was 1.464 found in Ceratotheca sesamoides for Ni in Bin Bukar Farm and 0.627 in Urena lobata for Cu in Custom Farm. The Transfer Factor values for Cd, Cu and Zn for the range of vegetables were not substantially high, except for Ni which the ratio was greater than one indicating that the plants have accumulated elements

Airway smooth muscle cells from severe asthma patients with fixed airflow obstruction are responsive to steroid and bronchodilator treatment in vitro

Asthma is characterised by recurrent symptoms associated with variable airflow obstruction and airway hyperresponsiveness, all of which are improved with combination inhaled corticosteroid (ICS)/long-acting β-agonist (LABA) treatment in mild-to-moderate asthma [1]. A proportion of patients however develop fixed airflow obstruction (FAO), despite optimised treatment. FAO is prevalent in up to 60% of patients with severe asthma and is associated with a more rapid decline in lung function and increased symptoms [2]. The underlying mechanisms of FAO in asthma are poorly understood; therefore, development of novel treatment strategies remains a challenge. Airway smooth muscle cells (ASMCs) are the major effector cells of bronchoconstriction in asthma and also contribute to the inflammatory process by secreting pro-inflammatory cytokines and chemokines. Therefore, ASMCs are a major target of both β2-agonist and ICS treatment [3]. Although several studies have suggested that steroid signalling [4] or β2-adrenoceptor (β2AR) signalling may be abnormally regulated in severe asthma [5], it remains unknown whether impaired airway smooth muscle corticosteroid and/or β2-agonist response may contribute to the development of FAO. The aim of this study was to investigate whether primary human ASMCs obtained from severe asthma patients with FAO differ in their response to β2-agonists and corticosteroids compared with asthma patients without FAO and healthy controls. We hypothesised that ASMCs from asthma patients with FAO are less responsive to corticosteroid and β2-agonist treatment than those from patients without FA

CoForTips Congo basin forests: tipping points for biodiversity conservation and resilience. Final Report (La modélisation des changements d’utilisation des terres dans les pays d’Afrique Centrale 2000-2030)

L'utilisation des terres est un facteur crucial pour le développement économique et l'environnement. Ainsi une terre dédiée à l’agriculture permettra une production régulière qui sera bénéfique pour satisfaire les besoins alimentaires des populations alentour et potentiellement, pour l’économie dans son ensemble. Par contre, les terres agricoles ont un contenu carbone bien inférieur à une terre forestière et sont généralement pauvres en biodiversité. Les terres peuvent être utilisées de différentes manières afin de répondre à différents objectifs et il peut être potentiellement difficile de satisfaire tous ces objectifs à la fois, donnant lieu à des choix difficiles lors de la conception des politiques. Les pays membres de la Commission des forêts d'Afrique centrale (COMIFAC) ont identifié l’initiative pour la réduction des émissions issues de la déforestation et de la dégradation forestière et l'amélioration des stocks de carbone (REDD+) comme un enjeu majeur dans la dernière revision du Plan de Convergence pour la Gestion Durable des Forêts, aux côtés de la conservation et de l’utilisation durable de la diversité biologique et de la réduction des impacts du changement climatique. Cette étude a pour objectif d’identifier les zones soumises aux pressions de conversion les plus fortes dans le futur et les conséquences en termes de production agricole, d’émissions de gaz à effet de serre (GES) et de risque de perte de biodiversité, avec pour but d’accompagner les institutions impliquées dans la REDD+ ainsi que dans la planification des Stratégies Nationales et Plans d’Action pour la Biodiversité dans les pays de la COMIFAC

A co-designed mHealth programme to support healthy lifestyles in Māori and Pasifika peoples in New Zealand (OL@-OR@):A cluster-randomised controlled trial

© 2019 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license Background: The OL@-OR@ mobile health programme was co-designed with Māori and Pasifika communities in New Zealand, to support healthy lifestyle behaviours. We aimed to determine whether use of the programme improved adherence to health-related guidelines among Māori and Pasifika communities in New Zealand compared with a control group on a waiting list for the programme. Methods: The OL@-OR@ trial was a 12-week, two-arm, cluster-randomised controlled trial. A cluster was defined as any distinct location or setting in New Zealand where people with shared interests or contexts congregated, such as churches, sports clubs, and community groups. Members of a cluster were eligible to participate if they were aged 18 years or older, had regular access to a mobile device or computer, and had regular internet access. Clusters of Māori and of Pasifika (separately) were randomly assigned (1:1) to either the intervention or control condition. The intervention group received the OL@-OR@ mHealth programme (smartphone app and website). The control group received a control version of the app that only collected baseline and outcome data. The primary outcome was self-reported adherence to health-related guidelines, which were measured with a composite health behaviour score (of physical activity, smoking, alcohol intake, and fruit and vegetable intake) at 12 weeks. The secondary outcomes were self-reported adherence to health-related behaviour guidelines at 4 weeks; self-reported bodyweight at 12 weeks; and holistic health and wellbeing status at 12 weeks, in all enrolled individuals in eligible clusters; and user engagement with the app, in individuals allocated to the intervention. Adverse events were not collected. This study is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12617001484336. Findings: Between Jan 24 and Aug 14, 2018, we enrolled 337 Māori participants from 19 clusters and 389 Pasifika participants from 18 clusters (n=726 participants) in the intervention group and 320 Māori participants from 15 clusters and 405 Pasifika participants from 17 clusters (n=725 participants) in the control group. Of these participants, 227 (67%) Māori participants and 347 (89%) Pasifika participants (n=574 participants) in the intervention group and 281 (88%) Māori participants and 369 (91%) Pasifika participants (n=650 participants) in the control group completed the 12-week follow-up and were included in the final analysis. Relative to baseline, adherence to health-related behaviour guidelines increased at 12 weeks in both groups (315 [43%] of 726 participants at baseline to 329 [57%] of 574 participants in the intervention group; 331 [46%] of 725 participants to 369 [57%] of 650 participants in the control group); however, there was no significant difference between intervention and control groups in adherence at 12 weeks (odds ratio [OR] 1·13; 95% CI 0·84–1·52; p=0·42). Furthermore, the proportion of participants adhering to guidelines on physical activity (351 [61%] of 574 intervention group participants vs 407 [63%] of 650 control group participants; OR 1·03, 95% CI 0·73–1·45; p=0·88), smoking (434 [76%] participants vs 501 [77%] participants; 1·12, 0·67–1·87; p=0·66), alcohol consumption (518 [90%] participants vs 596 [92%] participants; 0·73, 0·37–1·44; p=0·36), and fruit and vegetable intake (194 [34%] participants vs 196 [30%] participants; 1·08, 0·79–1·49; p=0·64) did not differ between groups. We found no significant differences between the intervention and control groups in any secondary outcome. 147 (26%) intervention group participants engaged with the OL@-OR@ programme (ie, set at least one behaviour change goal online). Interpretation: The OL@-OR@ mobile health programme did not improve adherence to health-related behaviour guidelines amongst Māori and Pasifika individuals. Funding: Healthier Lives He Oranga Hauora National Science Challenge

Application of isothermal titration calorimetry in evaluation of protein–nanoparticle interactions

Nanoparticles (NPs) offer a number of advantages over small organic molecules for controlling protein behaviour inside the cell. Protein binding to the surface of NPs depends on their surface characteristics, composition and method of preparation (Mandal et al. in J Hazard Mater 248–249:238–245, 2013). It is important to understand the binding affinities, stoichiometries and thermodynamical parameters of NP–protein interactions in order to see which interaction will have toxic and hazardous consequences and thus to prevent it. On the other side, because proteins are on the brink of stability, they may experience interactions with some types of NPs that are strong enough to cause denaturation or significantly change their conformations with concomitant loss of their biological function. Structural changes in the protein may cause exposure of new antigenic sites, “cryptic” peptide epitopes, potentially triggering an immune response which can promote autoimmune disease (Treuel et al. in ACS Nano 8(1):503–513, 2014). Mechanistic details of protein structural changes at NP surface have still remained elusive. Understanding the formation and persistence of the protein corona is critical issue; however, there are no many analytical methods which could provide detailed information about the NP–protein interaction characteristics and about protein structural changes caused by interactions with nanoparticles. The article reviews recent studies in NP–protein interactions research and application of isothermal titration calorimetry (ITC) in this research. The study of protein structural changes upon adsorption on nanoparticle surface and application of ITC in these studies is emphasized. The data illustrate that ITC is a versatile tool for evaluation of interactions between NPs and proteins. When coupled with other analytical methods, it is important analytical tool for monitoring conformational changes in proteins