Milene Miranda

The clinically approved antiviral drug sofosbuvir inhibits Zika virus replication.

Zika virus (ZIKV) is a member of the Flaviviridae family, along with other agents of clinical significance such as dengue (DENV) and hepatitis C (HCV) viruses. Since ZIKV causes neurological disorders during fetal development and in adulthood, antiviral drugs are necessary. Sofosbuvir is clinically approved for use against HCV and targets the protein that is most conserved among the members of the Flaviviridae family, the viral RNA polymerase. Indeed, we found that sofosbuvir inhibits ZIKV RNA polymerase, targeting conserved amino acid residues. Sofosbuvir inhibited ZIKV replication in different cellular systems, such as hepatoma (Huh-7) cells, neuroblastoma (SH-Sy5y) cells, neural stem cells (NSC) and brain organoids. In addition to the direct inhibition of the viral RNA polymerase, we observed that sofosbuvir also induced an increase in A-to-G mutations in the viral genome. Together, our data highlight a potential secondary use of sofosbuvir, an anti-HCV drug, against ZIKV.

Synthesis and Characterization of Cr2O3 Nanoparticles Obtained by Gelatin

Nanoparticles of Cr2O3 were synthesized by means of gelatin and (KCr(SO4)2 12H2O). The particle size measured with X-ray diffraction (XRD) technique and confirmed by Transmission Electron Microscopy (TEM) is in the range of 15-60nm. We demonstrated that particle size increase with the sintering temperature in the interval of 500-800C and the surface area decrease. Also, other complementary techniques such as SEM and TGA were used to confirm our results. Introduction The interest in the physical of nanoparticles has increased in the last decades because of the different properties encountered in these materials when compared to their corresponding bulk. Chromium oxide nanoparticles have several applications such as catalysis of CO [1] and H2S [2], green pigments [3], thermal protection [4], wear resistance [5,6] as in advanced digital recording systems [7] that depend on the crystalline size and morphology. Reduced particle size is also needed for improved sintering abilities, that means decreased sintering temperatures and increased density of sintered powders [8]. Several methods have been implemented in order to obtain the nanocrystalline chromium oxide, including microwave plasma [9], sol-gel [10,11] and mechanochemical processing [12]. From an idea similar to that of using coconut water [13] as a precursor to obtain metal oxide, in this work we used commercial gelatin assuming that both precursors are constituted of the protein in the gelatin composition. Recently, Fe2O3 was obtained by gelatin with particle size of 100 nm [14]. Also, gelatin was used as a new application in medicine to obtain drugs with dimension of nanometer [15].

Development of standard methods for Zika virus propagation, titration, and purification

The emergence of Zika virus (ZIKV) infection has stimulated several research groups to study and collaborate to understand virus biology and pathogenesis. These efforts may assist with the development of antiviral drugs, vaccines and diagnostic tests, as well as to promote advancements in public health policies. Here, we aim to develop standard protocols for propagation, titration, and purification of ZIKV strains, by systematically testing different cell types, kinetics, multiplicity of infection and centrifugation protocols. ZIKV produces a productive infection in human, non-human primate, and rodents-derived cell lines, with different efficacies. The highest yield of ZIKV-AFR and ZIKV-BR infectious progeny was obtained at 7days post infection in C6/36 cells (7×107 and 2×108 PFU/ml, respectively). However, high titers of ZIKV-AFR could be obtained at earlier time points in Vero cells (2.5×107PFU/ml at 72hpi), whereas ZIKV-BR titers reached 108 PFU/ml at 4dpi in C6/36 cells. High yield of purified virus was obtained by purification through a discontinuous sucrose gradient. This optimized procedure will certainly contribute to future studies of virus structure and vaccine development. Beyond the achievement of efficient virus propagation, the normalization of these protocols will also allow different laboratories around the world to better compare and discuss data regarding different features of ZIKV biology and disease, contributing to more efficient collaborations and progression in ZIKV research.

Rochelle salt piezoelectric coefficients obtained by x-ray multiple diffraction

In this paper, the theory of the method which uses the sensitivity and versatility of the multiple diffraction phenomenon to probe small lattice deformation induced by electric field (Avanci et al 1998 Phys. Rev. Lett. 81 5426) was implemented to provide a relationship between the E-induced strain in the Rochelle salt (ferroelectric phase) crystal and the shift in the Renninger scan peak position. From that, all piezoelectric coefficients in a piezoelectric tensor row (d21 = 7.0(6) × 10 −10 CN −1 ,d 22 = 2.2(9) × 10 −9 CN −1 , d23 = 2.1(9) × 10 −9 CN −1 and d25 = 3.7(8) × 10 −11 CN −1 ) were determined by using the primary reflections ( 600 ) and ( 800 ) found as the best choices for the experiments with E parallel to the [0 1 0] direction (the b-axis).

X-ray multiple diffraction as a probe to determine all the piezoelectric coefficients of a crystal: Rochelle salt case

The x-ray multiple diffraction method, which allows us to determine the piezoelectric coefficients of a single crystal under an external electric field (E), was applied to Rochelle salt (dos Santos et al 2001 J. Phys.: Condens. Matter 13 10497) for E parallel to the piezoelectric Y direction. In this work, the theory was extended to consider an observed monoclinic–triclinic distortion under E application into the other two piezoelectric X and Z directions. Renninger scans carried out using the chosen (060) primary reflection have provided the four remaining coefficients through the measurement of the properly chosen secondary peaks. so that all eight piezoelectric coefficients (d14, d16, d21, d22, d23, d25, d34 and d36) for Rochelle salt were determined.

Whole-genome sequences of influenza A(H3N2) viruses isolated from Brazilian patients with mild illness during the 2014 season

The influenza A(H3N2) virus has circulated worldwide for almost five decades and is the dominant subtype in most seasonal influenza epidemics, as occurred in the 2014 season in South America. In this study we evaluate five whole genome sequences of influenza A(H3N2) viruses detected in patients with mild illness collected from January-March 2014. To sequence the genomes, a new generation sequencing (NGS) protocol was performed using the Ion Torrent PGM platform. In addition to analysing the common genes, haemagglutinin, neuraminidase and matrix, our work also comprised internal genes. This was the first report of a whole genome analysis with Brazilian influenza A(H3N2) samples. Considerable amino acid variability was encountered in all gene segments, demonstrating the importance of studying the internal genes. NGS of whole genomes in this study will facilitate deeper virus characterisation, contributing to the improvement of influenza strain surveillance in Brazil.

Inhibitory effect of microalgae and cyanobacteria extracts on influenza virus replication and neuraminidase activity

Background The influenza virus can cause seasonal infections with mild to severe symptoms, circulating worldwide, and it can affect people in any age group. Therefore, this infection is a serious public health problem that causes severe illness and death in high-risk populations. Every year, 0.5% of the world’s population is infected by this pathogen. This percentage can increase up to ten times during pandemics. Influenza vaccination is the most effective way to prevent disease. In addition, anti-influenza drugs are essential for prophylactic and therapeutic interventions. The oseltamivir (OST, a neuraminidase inhibitor) is the primary antiviral used in clinics during outbreaks. However, OST resistant viruses may emerge naturally or due to antiviral pressure, with a prevalence of 1–2% worldwide. Thus, the search for new anti-influenza drugs is extremely important. Currently, several groups have been developing studies describing the biotechnological potential of microalgae and cyanobacteria, including antiviral activity of their extracts. In Brazil, this potential is poorly known and explored. Methods With the aim of increasing the knowledge on this topic, 38 extracts from microalgae and cyanobacteria isolated from marine and freshwater biomes in Brazil were tested against: cellular toxicity; OST-sensitive and resistant influenza replications; and neuraminidase activity. Results For this purpose, Madin-Darby Canine Kidney (MDCK)-infected cells were treated with 200 μg/mL of each extract. A total of 17 extracts (45%) inhibited influenza A replication, with seven of them resulting in more than 80% inhibition. Moreover, functional assays performed with viral neuraminidase revealed two extracts (from Leptolyngbya sp. and Chlorellaceae) with IC50 mean < 210 μg/mL for influenza A and B, and also OST-sensitive and resistant strains. Furthermore, MDCK cells exposed to 1 mg/mL of all the extracts showed viability higher than 80%. Discussion Our results suggest that extracts of microalgae and cyanobacteria have promising anti-influenza properties. Further chemical investigation should be conducted to isolate the active compounds for the development of new anti-influenza drugs. The data generated contribute to the knowledge of the biotechnological potential of Brazilian biomes that are still little explored for this purpose.

Corrigendum: The clinically approved antiviral drug sofosbuvir inhibits Zika virus replication

Scientific Reports 7: Article number: 40920; published online 18 January 2017; updated on 24 April 2017 The Competing Financial Interests section in this Article is incorrect and should read: “Dr. Karin Bruning is a member of the BMK consortium, able to produce sofosbuvir”.