Investigation of trypanothione reductase inhibitory activity by 1,3,4-thiadiazolium-2-aminide derivatives and molecular docking studies

The biological activities of a series of mesoionic 1,3,4-thiadiazolium-2-aminide derivatives have been studied. The most active compounds (MI-HH; MI-3-OCH(3); MI-4-OCH(3) and MI-4-NO(2)) were evaluated to determine their effect on trypanothione reductase (TryR) activity in Leishmania sp. and Trypanosoma cruzi. Among the assayed compounds, only MI-4-NO(2) showed enzyme inhibition effect on extracts from different cultures of parasites, which was confirmed using the recombinant enzyme from T. cruzi (TcTryR) and Leishmania infantum (LiTryR). The enzyme kinetics determined with LiTryR demonstrated a non-competitive inhibition profile of MI-4-NO(2). A molecular docking study showed that the mesoionic compounds could effectively dock into the substrate binding site together with the substrate molecule. The mesoionic compounds were also effective ligands of the NADPH and FAD binding sites and the NADPH binding site was predicted as the best of all three binding sites. Based on the theoretical results, an explanation at the molecular level is proposed for the MI-4-NO(2) enzyme inhibition effect. Given TryR as a molecular target, it is important to continue the study of mesoionic compounds as part of a drug discovery campaign against Leishmaniasis or Chagas' disease.     

Biodiversity influences ecosystem functioning in aquatic angiosperm communities

Knowledge of the connection between aquatic plant diversity and ecosystem processes is still limited. To examine how plant species diversity affects primary productivity, plant nutrient use, functional diversity of secondary producers and population/community stability, we manipulated submerged angiosperm species diversity in a field experiment lasting 15 weeks. Plant richness increased the shoot density for three of four species. Polyculture biomass production was enhanced by increasing richness, with positive complementarity and selection effects causing positive biodiversity effects. Species richness enhanced the community stability for biomass production and shoot density. Sediment ammonium availability decreased with plant diversity, suggesting improved nutrient usage with increasing plant richness. Interestingly, positive multitrophic effects of plant species richness on structural and functional diversity of macrobenthic secondary producers were recorded. The results suggest that mixed seagrass meadows play an important role for ecosystem functioning and thus contribute to the provision of goods and services in coastal areas.     

The role of biotic and abiotic cues in stimulating aggregation by larval cane toads (Rhinella marina)

Tadpoles of the cane toad (Rhinella marina) form dense aggregations in the field, but the proximate cues eliciting this behavior are not well understood. We sampled water‐bodies in the Northern Territory of Australia, finding that the density of cane toad tadpoles increased with increasing temperature. Furthermore, we conducted laboratory experiments to explore the roles of biotic factors (attraction to conspecifics; chemical cues from an injured conspecific; food) and spatially heterogeneous abiotic factors (light levels, water depth, physical structure) to identify the cues that induce tadpole aggregation. Annulus and binary choice trials demonstrated weak but significant attraction between conspecifics. Tadpoles decreased swimming speeds, but did not increase grouping in response to cues from an injured conspecific. Larvae aggregated in response to abiotic cues (high levels of illumination and proximity to physical structures) and were strongly attracted to feeding conspecifics. Overall, aggregation by cane toad tadpoles is likely driven by weak social attraction coupled with a shared preference for specific abiotic features, creating loose aggregations that are then reinforced by movement toward feeding conspecifics.     

An ER clamp for endosome fission

Endosomes are known to undergo budding and fission reactions that separate regions destined for lysosomal degradation from carriers to be recycled to the plasma membrane. A recent paper (Rowland et al, 2014 ) shows that contact sites between endosomes and the endoplasmic reticulum (ER) define the position and timing for fission. This uncovers an unanticipated role for the ER in controlling endosomal sorting and maturation.     

Parental food provisioning is related to nestling stress response in wild great tit nestlings: implications for the development of personality

Background

Variation in early nutrition is known to play an important role in shaping the behavioural development of individuals. Parental prey selection may have long-lasting behavioural influences. In birds foraging on arthropods, for instance, the specific prey types, e.g. spiders and caterpillars, matter as they have different levels of taurine which may have an effect on personality development. Here we investigated how naturally occurring variation in the amounts of spiders and caterpillars, provisioned to nestlings at day 4 and 8 after hatching, is related to the response to handling stress in a wild passerine, the great tit (Parus major). Broods were cross-fostered in a split-brood design allowing us to separate maternal and genetic effects from early rearing effects. Adult provisioning behaviour was monitored on day four and day eight after hatching using video recordings. Individual nestlings were subjected to a handling stress test at an age of 14 days, which is a validated proxy for exploratory behaviour as an adult.

Results

Variation in handling stress was mainly determined by the rearing environment. We show that, contrary to our predictions, not the amount of spider biomass, but the amount of caterpillar biomass delivered per nestling significantly affected individual performance in the stress test. Chicks provisioned with lower amounts of caterpillars exhibited a stronger stress response, reflecting faster exploratory behaviour later on in life, than individuals who received larger amounts of caterpillars.

Conclusions

These results suggest that natural variation in parental behaviour in wild birds modulates the developmental trajectories of their offspring's personality via food provisioning. Since parental provisioning behaviour might also reflect the local environmental conditions, provisioning behaviour may influence how nestlings respond to these local environmental conditions.

     

Effects of subthalamic deep brain stimulation on fixational eye movements in Parkinson’s disease

Journal of Computational Neuroscience - Miniature yoked eye movements, fixational saccades, are critical to counteract visual fading. Fixational saccades are followed by a return saccades forming...     

Introducing digital tools for sustainable food supply management: Tackling food loss and waste in industrial canteens

Reducing food waste is essential if we want to create a more sustainable food system, which is why halving per capita food waste by 2030 has been included in the UN Sustainable Development Goals. The main aim of this paper is to demonstrate that by using digital tools to monitor food provisioning and management within canteens, it is possible to achieve a more sustainable food service management within industrial companies and to reduce the overall quantity and environmental impacts of food preparation and consumption thus achieving economic benefits. Longitudinal 2018 and 2019 data collected from the canteen of a major Italian food production company were analyzed. The results showed that the amount of food lost and wasted has decreased over time, reaping important environmental benefits and illustrating specific differences between the food lost in meal preparation and the food left on employees’ plates. It is therefore important to implement education initiatives and to use digital tools to share food-related data collected within companies among both employees and kitchen and catering staff in order to raise awareness of their behavioral strengths and weaknesses. From this perspective, new interventions at both kitchen and customer/worker levels are introduced and discussed.