Differential ability to resist to complement lysis and invade host cells mediated by MBL in R4 and 860 strains of Trypanosoma cruzi

To produce an infection Trypanosoma cruzi must evade lysis by the complement system. During early stages of infection, the lectin pathway plays an important role in host defense and can be activated by binding of mannan-binding lectin (MBL) to carbohydrates on the surface of pathogens. We hypothesized that MBL has a dual role during parasite-host cell interaction as lectin complement pathway activator and as binding molecule to invade the host cell. We used two polarized strains of T. cruzi, R4 (susceptible) and 860 (resistant) strains, to investigate the role of MBL in complement-mediated lysis. Interestingly R4, but not 860 metacyclic strain, markedly increases the invasion of host cells, suggesting that MBL drives the invasion process while the parasite deactivates the Lectin complement pathway.     

The effect of hormonal condition on dose-dependent amphetamine-stimulated behaviors in the male rat

The effects of varying doses (1.25, 2.5, and 5.0 mg/kg, ip) of D-amphetamine sulfate (AMPH) on eight individual behaviors (Rearing, Grooming, Sniffing, Stationary, Gnawing, Head Bobbing, "Sleeping," and Licking) of Castrate + Oil-treated, Castrate + Testosterone Propionate (TP)-treated, and Intact male rats were examined. For Stationary, Sniffing, and "Sleeping" at 1.25 mg/kg AMPH and Rearing and Sniffing at the 2.5 mg/kg dose a significantly greater duration in the behavioral score was obtained for Castrate + Oil versus Castrate + TP and Intact males. These results indicate the complexity of the AMPH dose-response effects upon measurable behaviors, the alteration in the duration of these effects as a function of the hormonal condition of the male rat, and the importance of examining discrete components of behavior when hormone-amphetamine interactions are examined.     

Exploring the Limiting Open‐Circuit Voltage and the Voltage Loss Mechanism in Planar CH3NH3PbBr3 Perovskite Solar Cells

Perovskite solar cells based on CH₃NH₃PbBr₃ with a band gap of 2.3 eV are attracting intense research interests due to their high open‐circuit voltage (V_oc) potential, which is specifically relevant for the use in tandem configuration or spectral splitting. Many efforts have been performed to optimize the V_oc of CH₃NH₃PbBr₃ solar cells; however, the limiting V_oc (namely, radiative V_oc:V_oc,rad) and the corresponding ΔV_oc (the difference between V_oc,rad and V_oc) mechanism are still unknown. Here, the average V_oc of 1.50 V with the maximum value of 1.53 V at room temperature is achieved for a CH₃NH₃PbBr₃ solar cell. External quantum efficiency measurements with electroluminescence spectroscopy determine the V_oc,rad of CH₃NH₃PbBr₃ cells with 1.95 V and a ΔV_oc of 0.45 V at 295 K. When the temperature declines from 295 to 200 K, the obtained V_oc remains comparably stable in the vicinity of 1.5 V while the corresponding ΔV_oc values show a more significant increase. Our findings suggest that the V_oc of CH₃NH₃PbBr₃ cells is primarily limited by the interface losses induced by the charge extraction layer rather than by bulk dominated recombination losses. These findings are important for developing strategies how to further enhance the V_oc of CH₃NH₃PbBr₃‐based solar cells.     

Contrasting the distribution of butterflies and termites in plantations and tropical forests

In the tropics vast areas of natural forests are being converted into plantations. The magnitude of the resulting loss in arthropod biodiversity and associated ecosystem services represents a significant topic of research. In this study we contrasted the abundance, species richness and faunal turnover of butterflies, resident butterflies (i.e., whose host plants were ascertained to occur in the habitats studied) and termites between small (average 4.3 ha) 20+ year old exotic plantations (teak and Terminalia), native plantations (Cedro espino), and an old growth forest in Panama. We used Pollard walks and manual search to quantify the abundance or occurrence of butterflies and termites, respectively. In 2014 we observed 4610 butterflies representing 266 species and 108 termite encounters (out of 160 quadrats) representing 15 species. Butterflies were more abundant and diverse in plantations than in the forest, whereas this pattern was opposite for resident butterflies and termites. There was marked faunal turnover between plantations and forest. We conclude that (a) the magnitude of faunal changes between forest and plantations is less drastic for termites than for butterflies; (b) resident butterfly species are more impacted by the conversion of forest to plantations than all butterflies, including transient species; and (c) species richness does not necessarily decrease in the series forest > native > exotic plantations. Whereas there are advantages of studying more tractable taxa such as butterflies, the responses of such taxa can be highly unrepresentative of other invertebrate groups responsible for different ecological services.     

The binding of trivalent chromium to low-molecular-weight chromium-binding substance (LMWCr) and the transfer of chromium from transferrin and chromium picolinate to LMWCr

A recent model for the role of chromium in insulin signaling requires that the oligopeptide low-molecular-weight chromium-binding substance (LMWCr) tightly bind four chromic ions before the oligopeptide obtains a conformation required for binding to the tyrosine kinase active site of the insulin receptor. To test this model, the chromium-binding constant of LMWCr was determined, and the ability of LMWCr to remove chromium from Cr2-transferrin and the nutritional supplement chromium picolinate, Cr(pic)3, was examined. These results are consistent with the model of the mode of action of LMWCr; a Hill study indicates the four chromic ions bind to apoLMWCr in a highly cooperative fashion (n =3.47) with a binding constant of 1.54x 10(21). Chromium is readily transferred from transferrin to apoLMWCr at near neutral pH. The results also suggest that reduction of the chromic center of Cr(pic)3 may be required for the supplement to release chromium; thus, release of chromium is related to a mechanism by which Cr(pic)3 may generate hydroxyl radicals in cells.     

CANVS: an easy-to-use application for the analysis and visualization of mass spectrometry–based protein–protein interaction/association data

The elucidation of a protein’s interaction/association network is important for defining its biological function. Mass spectrometry–based proteomic approaches have emerged as powerful tools for identifying protein–protein interactions (PPIs) and protein–protein associations (PPAs). However, interactome/association experiments are difficult to interpret, considering the complexity and abundance of data that are generated. Although tools have been developed to identify protein interactions/associations quantitatively, there is still a pressing need for easy-to-use tools that allow users to contextualize their results. To address this, we developed CANVS, a computational pipeline that cleans, analyzes, and visualizes mass spectrometry–based interactome/association data. CANVS is wrapped as an interactive Shiny dashboard with simple requirements, allowing users to interface easily with the pipeline, analyze complex experimental data, and create PPI/A networks. The application integrates systems biology databases such as BioGRID and CORUM to contextualize the results. Furthermore, CANVS features a Gene Ontology tool that allows users to identify relevant GO terms in their results and create visual networks with proteins associated with relevant GO terms. Overall, CANVS is an easy-to-use application that benefits all researchers, especially those who lack an established bioinformatic pipeline and are interested in studying interactome/association data.