Protease inhibitors from Theobroma cacao impair SARS-CoV-2 replication in vitro.

SARS-CoV-2 is a newly emerging virus from the Coronaviridae family that has already infected over 700 million people worldwide and killed over 6 million. This virus uses protease molecules to replicate and infect the host, which makes these molecules targets for therapeutic substances to eliminate the virus and treat infected people. Through the protein-protein molecular docking approach, we detected two cystatins from Theobroma cacao, TcCYS3 and TcCYS4, described as papain-like protease inhibitors. These inhibitors decreased SARS-CoV-2 genomic copies without toxicity to Vero cells. There is a need to perform comprehensive studies in relevant animal models and to investigate the action mechanisms of protease inhibitors from Theobroma cacao that control the replication of SARS-CoV-2 in human cells.

Rational selection of hidden epitopes for a molecularly imprinted electrochemical sensor in the recognition of heat-denatured dengue NS1 protein.

Rational selection of predicted peptides to be employed as templates in molecular imprinting was carried out for the heat-denatured non-structural protein 1 (NS1) of dengue virus (DENV). Conservation analysis among 301 sequences of Brazilian isolates of DENV and zika virus (ZIKV) NS1 was carried out by UniProtKB, and peptide selection was based on in silico data of the conservational, structural and immunogenic properties of the sequences. The selected peptide (from dengue 1 NS1) was synthesized and employed as a template in the electropolymerization of polyaminophenol-imprinted films on the surface of carbon screen-printed electrodes. Heat denaturation of the protein was carried out prior to analysis, in order to expose its internal hidden epitopes. After removal of the template, the molecularly imprinted cavities were able to rebind to the whole denatured protein as determined by electrochemical impedance spectroscopy. This label-free sensor was efficient to distinguish the NS1 of DENV from the NS1 of ZIKV. Additionally, the sensor was also selective for dengue NS1, in comparison with human serum immunoglobulin G and human serum albumin. Additionally, the device was able to detect the DENV NS1 at concentrations from 50 to 200 µg L-1 (RSD below 5.04%, r = 0.9678) in diluted human serum samples. The calculated LOD and LOQ were, respectively, 29.3 and 88.7 µg L-1 and each sensor could be used for six sequential cycles with the same performance.

Serro 2 Virus Highlights the Fundamental Genomic and Biological Features of a Natural Vaccinia Virus Infecting Humans.

Vaccinia virus (VACV) has been implicated in infections of dairy cattle and humans, and outbreaks have substantially impacted local economies and public health in Brazil. During a 2005 outbreak, a VACV strain designated Serro 2 virus (S2V) was collected from a 30-year old male milker. Our aim was to phenotypically and genetically characterize this VACV Brazilian isolate. S2V produced small round plaques without associated comets when grown in BSC40 cells. Furthermore, S2V was less virulent than the prototype strain VACV-Western Reserve (WR) in a murine model of intradermal infection, producing a tiny lesion with virtually no surrounding inflammation. The genome of S2V was sequenced by primer walking. The coding region spans 184,572 bp and contains 211 predicted genes. Mutations in envelope genes specifically associated with small plaque phenotypes were not found in S2V; however, other alterations in amino acid sequences within these genes were identified. In addition, some immunomodulatory genes were truncated in S2V. Phylogenetic analysis using immune regulatory-related genes, besides the hemagglutinin gene, segregated the Brazilian viruses into two clusters, grouping the S2V into Brazilian VACV group 1. S2V is the first naturally-circulating human-associated VACV, with a low passage history, to be extensively genetically and phenotypically characterized.

Role of the suppressor of cytokine signaling 2 (SOCS2) during meningoencephalitis caused by Bovine herpesvirus 5 (BoHV-5).

The role of suppressors of cytokine signaling (SOCS) in meningoencephalitis caused by Bovine herpesvirus 5 (BoHV-5) was evaluated by intracranial infection in C57BL/6 wild-type mice (WT) and SOCS2 deficient mice (SOCS2(-/-)). Both infected groups presented weight loss, ruffled fur and hunched posture. Additionally, infected SOCS2(-/-) mice showed swollen chamfer and progressive depression. Infected WT animals developed mild meningitis, characterized by infiltration of mononuclear cells. Moreover, viral DNA was detected in liver and lung from infected WT group. This group also showed elevated brain levels of IFN-γ, IL-10, CXCL1 and CCL5, when compared with non-infected WT animals. Brain inflammation was exacerbated in infected SOCS2(-/-) mice with widespread distribution of the virus and increased brain levels of TNF-α, IFN-γ, IL-10, IL-12, CXCL1 and CCL5, when compared with WT infected mice. Moreover, infected SOCS2 deficient mice exhibited reduced brain mRNA expression of IFNα and IFNß and increased expression of mRNA of SOCS1, compared with infected WT mice. Taken together, our study provides an insight into the role of SOCS2 in modulating the immune response to BoHV-5 infection.

Outbreak of severe zoonotic vaccinia virus infection, Southeastern Brazil.

In 2010, a vaccinia virus isolate caused an atypically severe outbreak that affected humans and cattle in Brazil. Of 26 rural workers affected, 12 were hospitalized. Our data raise questions about the risk factors related to the increasing number and severity of vaccinia virus infections.