Mucosal and systemic T cell response in mice intragastrically infected with Neospora caninum tachyzoites

The murine model has been widely used to study the host immune response to Neospora caninum. However, in most studies, the intraperitoneal route was preferentially used to establish infection. Here, C57BL/6 mice were infected with N. caninum tachyzoites by the intragastric route, as it more closely resembles the natural route of infection through the gastrointestinal tract. The elicited T-cell mediated immune response was evaluated in the intestinal epithelium and mesenteric lymph nodes (MLN). Early upon the parasitic challenge, IL-12 production by conventional and plasmacytoid dendritic cells was increased in MLN. Accordingly, increased proportions and numbers of TCRαβ⁺CD8⁺IFN-γ⁺ lymphocytes were detected, not only in the intestinal epithelium and MLN, but also in the spleen of the infected mice. In this organ, IFN-γ-producing TCRαβ⁺CD4⁺ T cells were also found to increase in the infected mice, however later than CD8⁺ T cells. Interestingly, splenic and MLN CD4⁺CD25⁺ T cells sorted from infected mice presented a suppressive activity on in vitro T cell proliferation and cytokine production above that of control counterparts. These results altogether indicate that, by producing IFN-γ, TCRαβ⁺CD8⁺ cells contribute for local and systemic host protection in the earliest days upon infection established through the gastrointestinal tract. Nevertheless, they also provide substantial evidence for a parasite-driven reinforcement of T regulatory cell function which may contribute for parasite persistence in the host and might represent an additional barrier to overcome towards effective vaccination.     

Direct observation of molecular preorganization for chirality transfer on a catalyst surface

The chemisorption of specific optically active compounds on metal surfaces can create catalytically active chirality transfer sites. However, the mechanism through which these sites bias the stereoselectivity of reactions (typically hydrogenations) is generally assumed to be so complex that continued progress in the area is uncertain. We show that the investigation of heterogeneous asymmetric induction with single-site resolution sufficient to distinguish stereochemical conformations at the submolecular level is finally accessible. A combination of scanning tunneling microscopy and density functional theory calculations reveals the stereodirecting forces governing preorganization into precise chiral modifier-substrate bimolecular surface complexes. The study shows that the chiral modifier induces prochiral switching on the surface and that different prochiral ratios prevail at different submolecular binding sites on the modifier at the reaction temperature.     

Model-based optimal delineation of drip irrigation management zones

Precision Agriculture - Delineation of management zones for applying Variable Rate Irrigation (VRI) in drip irrigation presents unique challenges due to the directionality of the drip lines and the...     

High-yielding preparation of a stable precursor of hydroxytyrosol by total synthesis and from the natural glycoside oleuropein

The unprecedented acetonide of the antioxidant hydroxytyrosol has been synthesized by a two-step high-yielding procedure and found to be both purifiable by chromatography and stable over a wide pH range. The protection stabilizes hydroxytyrosol against oxidation, thereby allowing long-term storage. The protection can quantitatively be removed, under nonaqueous conditions, to afford pure hydroxytyrosol suitable for use as an additive in food and cosmetic preparations. Extension of the same methodology to the natural and easily accessible glycoside oleuropein, followed by saponification of the resulting complex mixture of acetonides, allowed hydroxytyrosol acetonide to be recovered in high yield. This constitutes a new interesting methodology to obtain the antioxidant hydroxytyrosol.     

Assessing the potential of marine Natura 2000 sites to produce ecosystem‐wide effects in rocky reefs: A case study from Sardinia Island (Italy)

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Fish reproductive activity reveals temporal variations predominating spatial heterogeneity in maintaining high functional diversity of a Neotropical reservoir

The reproductive activity of the fish assemblage in a large Neotropical reservoir was evaluated by surveying the occurrence of ichthyoplankton in response to spatial and temporal variation in environmental factors. Fish reproduction was investigated by capturing larvae along representative spatial gradients in the main body (longitudinal) and arms (lateral) of the reservoir. After identification, the captured larvae were classified into different groups according to the functional traits of their parental stock. Sampling occurred monthly at night from October to March over five reproductive periods between 2009 and 2016, using conical-cylindrical plankton nets with flowmeter. Water samples were taken simultaneously allowing the measurement of environmental factors related to reproductive activity. The relationship between the environmental factors and the functional traits was assessed using RLQ and fourth-corner analyses. An evaluation of 51,995 larvae revealed there was greater larval abundance in the lacustrine and transition zones of both longitudinal and lateral gradients. Occurrences often correlated with temporal instead of spatial gradients. Higher rainfall correlated with abundances of detritivorous and migratory species. Higher water levels correlated with higher abundances of non-native species, species without parental care, with external fecundation, and partial spawning. Dry periods, with lower water and higher dissolved oxygen, correlated with higher abundances of insectivores and sedentary species. Although the presence of a dam-free stretch of river upstream of the reservoir had a positive influence on fish larvae in the fluvial zone, the results did not show differentiation along either gradient. Thus, the composition of the functional groups of fish species that reproduce in the Itaipu Reservoir appears to be predominantly influenced by the temporal variation in environmental factors rather than the formation of spatial gradients.     

Soil quality and fertility in sustainable agriculture,with a contribution to the biological classification of agricultural soils

Soils and crops are particularly vulnerable to climate change and environmental stresses. In many agrosystems, soil biodiversity and ecosystem services provided by soils are under threat from a range of natural and human drivers. Agricultural soils are often subject to agronomic practices that disrupt soil trophic networks and make soils less productive in the long term. In this scenario, sustainable soil use aimed at improving plant/root status, growth and development plays a crucial role for enhancing the biological capacity of agricultural soils. This commentary paper is divided into the following four main sections: (i) the contentious nature of soil organic matter; (ii) soil biological quality/fertility; (iii) soil classification; and, (iv) which agricultural practices can be defined as sustainable? The published literature was analyzed within a holistic framework, with agrosystems considered as living systems where soil, vegetation, fauna and microorganisms co-evolve and are reciprocally influenced. Ultimately, this article will suggest a better stewardship of agricultural soils as a natural capital.