Uso de nanobast?es de ouro para o desenvolvimento de aulas pr?ticas de nanotecnologia.

Use of gold nanoparticles functionalization experiment was conducted in a biotechnology summer course at UFOP as a model for the introduction of the laboratory practice in nanotechnology for postgraduate courses in the areas of chemistry and biotechnology. The gold nanorods were synthesized by the seed method and then, functionalized with anti-IL-6 antibodies using the reagents EDAC/NHS and polyethyleneimine (PEI). This nanocompound was tested against the binding with the specific antigen (IL-6) and changes in the longitudinal plasmon absorption spectrum showed the coupling efficiency, which was also verified by the decrease in zeta potential. The experiment was satisfactory, with a positive feedback from participants, and could be implemented in nanotechnology practical classes from postgraduate courses, as a way for improve education in the emergent area of nanobiotechnology

Implications of oxidative stress on viral pathogenesis.

Reactive species are frequently formed after viral infections. Antioxidant defences, including enzymatic and non-enzymatic components, protect against reactive species, but sometimes these defences are not completely adequate. An imbalance in the production of reactive species and the body?s inability to detoxify these reactive species is referred to as oxidative stress. The aim of this review is to analyse the role of oxidative stress in the pathogenesis of viral infections and highlight some major therapeutic approaches that have gained importance, with regards to controlling virus-induced oxidative injury. Attention will be focused on DNA viruses (papillomaviruses, hepadnaviruses), RNA viruses (flaviviruses, orthomyxoviruses, paramyxoviruses, togaviruses) and retroviruses (human immunodeficiency virus). In general, viruses cause an imbalance in the cellular redox environment, which depending on the virus and the cell can result in different responses, e.g. cell signaling, antioxidant defences, reactive species, and other processes. Therefore, the modulation of reactive species production and oxidative stress potentially represents a novel pharmacological approach for reducing the consequences of viral pathogenesis

Combination of extracts from Aristolochia cymbifera with streptomycin as a potential antibacterial drug.

The appearance of new antibiotic-resistant bacteria is a societal problem that requires the development of new alternative treatments. Therefore, this work evaluated the antibacterial activity of ethanolic (EHI), dichloromethanic (EDI) and hexanic (EHE) extracts from Aristolochia cymbifera stems and the combination of these extracts with an antimicrobial drug to develop a new antibacterial therapy. The EDI, EHE and EHI extracts were obtained by maceration using three different solvents. The minimal inhibitory concentrations (MIC) of these extracts were determined using the microdilution test to determine the antibacterial potential of these extracts and their combination with streptomycin against Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae and Shigella flexneri. The extract dose leading to the cytotoxicity of 50% of the cells (CC50) was evaluated using mammalian cells MA104 and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The extracts had a MIC under 500 mg/L and a CC50 lower than 50 mg/L. The antibiotic/extract proportion influenced the antibacterial activity of the mixtures, and the proportion that optimized the antibacterial activity of streptomycin was a mixture that contained 75 percent of extract. This composition included less than 6.5 mg/L of extract and 2.5 mg/L of streptomycin and has potential as a new antibacterial therapy

Oxidative stress in Mayaro virus infection.

Mayaro virus (MAYV) is a neglected tropical arbovirus that causes a febrile syndrome that is sometimes accompanied by incapacitating arthritis/arthralgia. The pathogenesis of MAYV has not been completely defined and oxidative stress mediated by an increase in reactive oxygen species (ROS) and/or depletion of antioxidant defences has been found to contribute to several aspects of viral disease. To investigate whether MAYV induced oxidative stress in host cells, we monitored ROS production, oxidative stress markers and antioxidant defences at different time points after infection. Our results show that MAYV induced significant oxidative stress in infected HepG2 cells, as indicated by the increase of malondialdehyde (MDA) and protein carbonyl levels, and by a significant decrease of the reduced versus oxidized glutathione (GSH/GSSG) ratio. Generally, MAYV-infected HepG2 cells also showed an increase in antioxidant defences. We observed an increase in the superoxide dismutase (SOD) and catalase (CAT) activities and the total glutathione content. To determine whether similar effects occurred in other cell types, we evaluated the ROS, MDA and SOD activity levels in J774 cells after MAYV infection. Similar to our observations in HepG2 cells, the J774 cells showed an increase in ROS, MDA and total SOD activity following MAYV infection. Thus, since the cellular redox environment is influenced by the production and removal of ROS, we hypothesize that the overproduction of ROS was responsible for the oxidative stress in response to the MAYV infection despite the increase in the antioxidant status. This study is the first report on the involvement of oxidative stress during MAYV infection. Collectively, our data shed light on some mechanisms that are operational in host cells following exposure to MAYV

Evaluation of the activity of Tontelea micrantha extracts against Bacteria, Candida and Mayaro virus.

Objectives: This work aimed to evaluate the antibacterial, antifungal, and anti-Mayaro virus(MAYV) activity of leaf and branch extracts from Tontelea micrantha. Materials and Methods: T. micrantha extracts were prepared through the partition of the leaf and branch samples in different solvents. Then, the antibacterial and antifungal activity was assessed against bacterial pathogens and Candida sp. by the determination of the minimum inhibitory concentration (MIC) by the broth microdilution method. The activity against anti-MAYV was evaluated through the quantification of the extract concentration that promoted the protection of 50% of the cells after the viral infection. Results: The extracts of T. micrantha were inactive (MIC >500 ?g/mL) against Gram-positive, Gram-negative and Candida species at the highest concentration tested (500 ?g/mL). Anti-MAYV activity was also not detected, with SI <10, ranging from 1.2 to 3.6. Conclusion: Although it is used in traditional medicine, Leaf and branch extracts from T. micrantha did not present antimicrobial activity, which could be caused by the antagonistic effect of the compounds present in the extract

The hypocholesterolemic activity of a?a? (Euterpe oleracea Mart.) is mediated by the enhanced expression of the ATP-binding cassette, subfamily G transporters 5 and 8 and low-density lipoprotein receptor genes in the rat.

Previous studies have demonstrated that the ingestion of a?a? pulp can improve serum lipid profile in various animal models; therefore, we hypothesized that a?a? pulp (Euterpe oleracea Mart.) may modulate the expression of the genes involved in cholesterol homeostasis in the liver and increase fecal excretion, thus reducing serum cholesterol. To test this hypothesis, we analyzed the expression of 7?-hydroxylase and ATP-binding cassette, subfamily G transporters (ABCG5 and ABCG8), which are genes involved with the secretion of cholesterol in the rat. We also evaluated the expression of sterol regulatory element?binding protein 2, 3-hydroxy-3-methylglutaryl CoA reductase, low-density lipoprotein receptor (LDL-R), and apolipoprotein B100, which are involved in cholesterol biosynthesis. Female Fischer rats were divided into 4 groups: the C group, which was fed a standard AIN-93 M diet; the CA group, which was fed a standard diet supplemented with 2% a?a? pulp; the H group, which was fed a hypercholesterolemic diet (25% soy oil and 1% cholesterol); and the HA group, which was fed a hypercholesterolemic diet supplemented with 2% a?a? pulp. At the end of the experimental period, the rats were euthanized, and their blood and livers were collected. The HA group exhibited a significant decrease in serum total cholesterol, low-density lipoprotein cholesterol, and atherogenic index and also had increased high-density lipoprotein cholesterol and cholesterol excretion in feces compared with the H group. In addition, the expression of the LDL-R, ABCG5, and ABCG8 genes was significantly increased by the presence of a?a? pulp. These results suggest that a?a? pulp promotes a hypocholesterolemic effect in a rat model of dietary-induced hypercholesterolemia through an increase in the expression of ATP-binding cassette, subfamily G transporters and LDL-R genes

Caraparu virus induces damage and alterations in antioxidant defenses in the liver of BALB/c mice after subcutaneous infection.

Oxidative stress is a disturbance in the oxidantantioxidant balance leading to potential cellular damage. Most cells can tolerate a mild degree of oxidative stress because they have a system that counteracts oxidation that includes antioxidant molecules such as glutathione (GSH) and superoxide dismutase (SOD). Disruption of the host antioxidant status has been recognized as an important contributor to the pathogenesis of many viruses. Caraparu virus (CARV) is a member of group C of the Bunyaviridae family of viruses. In South American countries, group C bunyaviruses are among the common agents of human febrile illness and have caused multiple notable outbreaks of human disease in recent decades; nevertheless, little is known about the pathogenic characteristics of these viruses. The purpose of this study was to examine the hepatic pathogenesis of CARV in mice and the involvement of oxidative stress and antioxidant defenses on this pathology. Following subcutaneous infection of BALB/c mice, CARV was detected in the liver, and histopathology revealed acute hepatitis. Increased serum levels of aspartate and alanine aminotransferases (AST/ALT) and greater hepatic expression of the proinflammatory cytokine tumor necrosis factor- a (TNF-a) were found in infected animals. CARV infection did not alter the biomarkers of oxidative stress but caused an increase in GSH content and altered the expression and activity of SOD. This is the first report of an alteration of oxidative homeostasis upon CARV infection, which may, in part, explain the hepatic pathogenesis of this virus, as well as the pathogenesis of other Bunyaviridae members

Detection of the antiviral activity of epicatechin isolated from Salacia crassifolia (Celastraceae) against Mayaro virus based on protein C homology modelling and virtual screening.

Mayaro fever, caused by Mayaro virus (MAYV) is a sub-lethal disease with symptoms that are easily confused with those of dengue fever, except for polyarthralgia, which may culminate in physical incapacitation. Recently, outbreaks of MAYV have been documented in metropolitan areas, and to date, there is no therapy or vaccine available. Moreover, there is no information regarding the three-dimensional structure of the viral proteins of MAYV, which is important in the search for antivirals. In this work, we constructed a three-dimensional model of protein C of MAYV by homology modelling, and this was employed in a manner similar to that of receptors in virtual screening studies to evaluate 590 molecules as prospective antiviral agents. In vitro bioassays were utilized to confirm the potential antiviral activity of the flavonoid epicatechin isolated from Salacia crassifolia (Celastraceae). The virtual screening showed that six flavonoids were promising ligands for protein C. The bioassays showed potent antiviral action of epicatechin, which protected the cells from almost all of the effects of viral infection. An effective concentration (EC50) of 0.247 ?mol/mL was observed with a selectivity index (SI) of 7. The cytotoxicity assay showed that epicatechin has low toxicity, with a 50% cytotoxic concentration (CC50) greater than 1.723 ?mol/mL. Epicatechin was found to be twice as potent as the reference antiviral ribavirin. Furthermore, a replication kinetics assay showed a strong inhibitory effect of epicatechin on MAYV growth, with a reduction of at least four logs in virus production. Our results indicate that epicatechin is a promising candidate for further testing as an antiviral agent against Mayaro virus and other alphaviruses

Antiviral activity of silymarin against Mayaro virus and protective effect in virus-induced oxidative stress.

Mayaro virus (MAYV) is a neglected arbovirus belonging to the family Togaviridae. Its infection leads to Mayaro fever, with clinical manifestations such as fever, myalgia, headache, rash, arthralgia, vomiting, and diarrhea. The most prominent complaint from infected person is the long-lasting arthritis/arthralgia. The treatment for Mayaro fever is mainly symptom-based and there are no vaccines or antiviral drugs currently available, thus, natural products with anti-MAYV activity may provide a potential alternative. Recent evidences suggest that oxidative stress plays an important role in MAYV infection and compounds capable of modulating oxidative stress could represent a novel therapeutic approach in modulating MAYV-associated oxidative cellular damage. Silymarin is a complex extracted of Silybum marianum, or milk thistle, and its major active compound is silybin, which has a remarkable biological effect. Its antioxidant and antiviral effects, including its antiviral activity against the Chikungunya virus (CHIKV), prompted us to think whether silymarin could also reduce the replication of the MAYV and restore the pro-oxidant/antioxidant balance in the context of MAYV infection, leading to reduced cellular oxidative stress. We assessed the antiviral activity and protective effect of silymarin against oxidative stress in MAYV-infected HepG2 cells. Cytopathic effect inhibition, viral replication, and plaque reduction assays were used to determine the anti-MAYV activity of silymarin. Additionally, we determined whether silymarin could reduce MAYV-induced oxidative cell damage. Briefly, silymarin exhibited potent antiviral activity against MAYV and reduced MAYV-induced ROS formation and levels of malondialdehyde (MDA) and carbonyl protein, which are biomarkers of oxidative stress. In conclusion, the ability of silymarin to inhibit MAYV replication and attenuate MAYV-induce oxidative stress warrants further investigation of this compound as a novel therapeutic approach to Mayaro fever disease

Identification of a phylogenetically distinct orthobunyavirus from group C.

Apeu virus (APEUV) (family Bunyaviridae, genus Orthobunyavirus) was plaque purified and characterised by serological and molecular analysis. Neutralising assays confirmed cross-reactivity between purified APEUV clones and the Caraparu virus complex of group C orthobunyaviruses. Partial sequencing of the L, M and S segments of one APEUV clone (APEUV-CL5) was carried out. A phylogenetic tree constructed with the L amino acid sequences clustered APEUV-CL5 within the genus Orthobunyavirus, confirming its serological classification. Analysis of M segment sequences clustered APEUV-CL5 in the Caraparu virus complex (Group C), in agreement with serological tests and previous molecular characterisation. However, the sequence of the nucleocapsid gene (N) gave low identity values when compared to those of the group C viruses. The phylogenetic tree based on N nucleotide sequences clustered APEUV-CL5 next to the California and Bwamba groups. This remarkable S nucleotide variability suggests that APEUV-CL5 could be a genetic reassortant and that this evolutionary mechanism is present in the history of the group C viruses