Designer solvent ability of alcohols in aqueous biphasic systems composed of deep eutectic solvents and potassium phosphate

Deep eutectic solvents (DES) have been proposed as phase forming components of aqueous biphasic systems (ABS). However, the DES hydrogen bonding complexes are not stable in the high concentrations of water present in this type of systems. Therefore, as previously shown, DES-based ABS should be treated as quaternary systems. This confers DES-based ABS with an extra degree of freedom for the design of separation processes since while one of the DES components acts as a phase forming component, the other could induce the modification of the ABS phase properties and, consequently, the control of the partition of various biomolecules. In this context, the designer solvent effect of the hydrogen bond donor (HBD), using four different alcohols – ethanol, n-propanol 1,2-propanediol and ethylene glycol – mixed at three different molar fractions (2:1; 1:1 and 1:2) with cholinium chloride (the hydrogen bond acceptor, HBA) in quaternary systems composed of K2HPO4 and water, was evaluated in this work. The results show that the presence of the HBD has an impact upon the liquid–liquid equilibrium, and these changes are dependent on the alcohol nature. The NRTL model was correlated to the tie-line experimental data with a low mean deviation. Moreover, several biomolecules (phenolic compounds, alkaloids, and amino acids) were use as molecular probes to evaluate the ability of alcohols to tune the partition in the studied systems. The alcohol presence changes the properties of the ABS’s phases and it is here shown that the HBD of the DES can indeed be used to modulate the partition behavior of target molecules.publishe

Understanding the role of the hydrogen bond donor of the deep eutectic solvents in the formation of the aqueous biphasic systems

Deep eutectic solvents (DES) have been proposed as phase-forming compounds of aqueous biphasic systems (ABS). However, due to DES nature and the high water content of the ABS, their nature and behavior remains controversial. To foster the understanding of DES-based ABS, the present work uses the relative hydrophilicity of the hydrogen bond donor (HBD) as a descriptor to clarify its role on ABS for- mation and phase properties. Dipotassium phosphate (K2HPO4)-based ABS phase diagrams composed of cholinium chloride ([N111(2OH)]Cl), as hydrogen bond acceptor (HBA), and several HBD (alcohols and sugars) were compared in molality units and the saturation solubility point for each binodal curve determined. The results here reported establish the HBD role as function of its relative hydrophilicity: very hydrophilic HBD act only as an adjuvant in the formation of ABS; HBD of intermediate hydrophilicity influence the ABS formation; while the most hydrophobic HBD tend to form organic-aqueous two-phase systems, where the HBA acts as an adjuvant to the system.publishe

Schistosoma mansoni Stomatin Like Protein-2 Is Located in the Tegument and Induces Partial Protection against Challenge Infection

Schistosomiasis is a parasitic disease causing serious chronic morbidity in tropical countries. Together with the publication of the transcriptome database, a series of new vaccine candidates were proposed based on their functional classification. However, the prediction of vaccine candidates from sequence information or even by proteomics or microarrays data is somewhat speculative and there remains the considerable task of functional analysis of each new gene/protein. In this study, we present the characterization of one of these molecules, a stomatin like protein 2 (SmStoLP-2). Sequence analysis predicts signals that could contribute to protein membrane association and mitochondrial targeting, which was confirmed by differential extractions of schistosome tegument membranes and mitochondria. Additionally, confocal microscope analysis showed SmStoLP-2 present in the tegument of 7-day-old schistosomula and adult worms. Studies in patients living in endemic areas for schistosomiasis revealed high levels of IgG1, IgG2, IgG3 and IgA anti-SmStoLP-2 antibodies in individuals resistant to reinfection. Recombinant SmStoLP-2 protein, when used as vaccine, induced significant levels of protection in mice. This reduction in worm burden was associated with a typical Th1-type immune response. These results indicate that SmStoLP-2 could be useful in association with other antigens for the composition of a vaccine against schistosomiasis

On the three-finger protein domain fold and CD59-like proteins in Schistosoma mansoni

Background: It is believed that schistosomes evade complement-mediated killing by expressing regulatory proteins on their surface. Recently, six homologues of human CD59, an important inhibitor of the complement system membrane attack complex, were identified in the schistosome genome. Therefore, it is important to investigate whether these molecules could act as CD59-like complement inhibitors in schistosomes as part of an immune evasion strategy. Methodology/Principal Findings: Herein, we describe the molecular characterization of seven putative SmCD59-like genes and attempt to address the putative biological function of two isoforms. Superimposition analysis of the 3D structure of hCD59 and schistosome sequences revealed that they contain the three-fingered protein domain (TFPD). However, the conserved amino acid residues involved in complement recognition in mammals could not be identified. Real-time RT-PCR and Western blot analysis determined that most of these genes are up-regulated in the transition from free-living cercaria to adult worm stage. Immunolocalization experiments and tegument preparations confirm that at least some of the SmCD59-like proteins are surface-localized; however, significant expression was also detected in internal tissues of adult worms. Finally, the involvement of two SmCD59 proteins in complement inhibition was evaluated by three different approaches: (i) a hemolytic assay using recombinant soluble forms expressed in Pichia pastoris and E. coli; (ii) complement-resistance of CHO cells expressing the respective membrane-anchored proteins; and (iii) the complement killing of schistosomula after gene suppression by RNAi. Our data indicated that these proteins are not involved in the regulation of complement activation. Conclusions: Our results suggest that this group of proteins belongs to the TFPD superfamily. Their expression is associated to intra-host stages, present in the tegument surface, and also in intra-parasite tissues. Three distinct approaches using SmCD59 proteins to inhibit complement strongly suggested that these proteins are not complement inhibitors and their function in schistosomes remains to be determined.Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP, Grant Number:04/12872-3)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)National Institute of Health, National Institute of Allergy and Infectious Diseases (NIH-NIAID), Grant AI-095893NIH-NIAID Grant AI-056273FAPESP 00/11624-

Rehabilitation and release of confiscated songbirds into the wild: A pilot study

Songbirds are currently the most prevalent animals in illegal trafficking in Brazil and other countries, so they are often confiscated, and this poses legal, ethical, and conservation challenges. Returning them to nature requires complex and expensive management, a topic that is sparingly addressed in the literature. Here, we described the processes and costs associated with an attempt to rehabilitate and release confiscated songbirds into the wild. A total of 1,721 songbirds of several species were quarantined, rehabilitated, and released, primarily on two farms located within their typical geographical distribution. Health assessments were performed on samples from 370 birds. Serology revealed no antibodies against Newcastle disease, and Salmonella spp. cultures were negative. Real-time polymerase chain reactions detected M. gallisepticum in samples from seven birds. Atoxoplasma spp. and Acuaria spp. infections, sepsis, and trauma were the top causes of bird death. About 6% of the released birds were recaptured, within an average period of 249 days after release, and at a mean distance of 2,397 meters from the release sites. The majority of these birds were found with free-living mates within or close to fragments of transitional ecoregions with native or cultivated grasslands, and native groves/forests, and shrublands. However, eucalyptus plantations with rich understory regeneration provided a suitable environment for the released forest species to settle, since they were recaptured during the defense of these sites. Over half of the recaptured birds presented behavioral profiles with both dominant and tame traits. Birds with dominant traits are more likely to settle in habitats and face the live decoys during fieldwork, whereas birds with tame characteristics tend to accept close contact with humans. Ultramarine grosbeak (Cyanoloxia brissonii), the least common species among those released, at the release sites showed an almost 2-fold recapture rate in the shortest mean distances from the release sites. This suggests less territory competition, perhaps a major factor of bird re-establishment here. The total per-bird cost was USD 57. Our findings suggested suitable survival and re-establishment of confiscated songbirds in the wild, when managed as we describe

SARS-CoV-2 uses CD4 to infect T helper lymphocytes

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of a major global outbreak of respiratory tract disease known as Coronavirus Disease 2019 (COVID-19). SARS-CoV-2 infects mainly lungs and may cause several immune-related complications, such as lymphocytopenia and cytokine storm, which are associated with the severity of the disease and predict mortality. The mechanism by which SARS-CoV-2 infection may result in immune system dysfunction is still not fully understood. Here, we show that SARS-CoV-2 infects human CD4+ T helper cells, but not CD8+ T cells, and is present in blood and bronchoalveolar lavage T helper cells of severe COVID-19 patients. We demonstrated that SARS-CoV-2 spike glycoprotein (S) directly binds to the CD4 molecule, which in turn mediates the entry of SARS-CoV-2 in T helper cells. This leads to impaired CD4 T cell function and may cause cell death. SARS-CoV-2-infected T helper cells express higher levels of IL-10, which is associated with viral persistence and disease severity. Thus, CD4-mediated SARS-CoV-2 infection of T helper cells may contribute to a poor immune response in COVID-19 patients.</p

SARS-CoV-2 uses CD4 to infect T helper lymphocytes

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of a major global outbreak of respiratory tract disease known as Coronavirus Disease 2019 (COVID-19). SARS-CoV-2 infects mainly lungs and may cause several immune-related complications, such as lymphocytopenia and cytokine storm, which are associated with the severity of the disease and predict mortality. The mechanism by which SARS-CoV-2 infection may result in immune system dysfunction is still not fully understood. Here, we show that SARS-CoV-2 infects human CD4+ T helper cells, but not CD8+ T cells, and is present in blood and bronchoalveolar lavage T helper cells of severe COVID-19 patients. We demonstrated that SARS-CoV-2 spike glycoprotein (S) directly binds to the CD4 molecule, which in turn mediates the entry of SARS-CoV-2 in T helper cells. This leads to impaired CD4 T cell function and may cause cell death. SARS-CoV-2-infected T helper cells express higher levels of IL-10, which is associated with viral persistence and disease severity. Thus, CD4-mediated SARS-CoV-2 infection of T helper cells may contribute to a poor immune response in COVID-19 patients.</p