Emerson José Venancio

Enzymatic properties of venoms from Brazilian scorpions of Tityus genus and the neutralisation potential of therapeutical antivenoms.

Tityus scorpion stings are an important public health problem in Brazil, where the incidence of such stings exceeds the incidence of the health problems caused by other venomous animals, including snakes. In this study, we have analysed specific enzymatic activities of the venom from the Brazilian scorpions of Tityus genus, i.e., Tityus serrulatus, Tityus bahiensis and Tityus stigmurus. The data presented here revealed that Tityus spp. venoms exhibited significant hyaluronidase activity but no phospholipase activity. All the venom samples exhibited the ability to hydrolyse Abz-FLRRV-EDDnp and dynorphin 1-13 substrates. These activities were inhibited by 1,10-phenanthroline but not by PMSF, indicating the presence of metalloproteinases in the Tityus spp. venoms. The venom peptidase activity on Abz-FLRRV-EDDnp and on dynorphin 1-13 was partially inhibited by therapeutic Brazilian anti-scorpion and anti-arachnidic antivenoms. Dynorphin 1-13 (YGGFLRRIRPKLK) contains two scissile bonds between the residues Leu-Arg and Arg-Arg that are susceptible to cleavage by the Tityus venom metallopeptidase(s). Their cleavage releases leu-enkephalin, an important bioactive peptide. The detection of metalloproteinase(s) with specificity for both dynorphin 1-13 degradation and leu-enkephalin releasing can be important for the mechanistic understanding of hypotension and bradycardia induction in cases of scorpion stings, whereas hyaluronidases might contribute to the diffusion of the toxins present in these venoms. Furthermore, the limited inhibition of the toxic enzymatic activities by commercial antivenoms illustrates the necessity of improvements in current antivenom preparation.

Detection of OXA-231, a new variant of blaOXA-143, in Acinetobacter baumannii from Brazil: a case report

Department of Microbiology, Universidade Estadual de Londrina, Londrina, Paraná, Brazil; Department of Science Pathological, Universidade Estadual de Londrina, Londrina, Paraná, Brazil; Laboratório ALERTA, Division of Infectious Diseases, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil; Department of Pathology, Clinical and Toxicological Analysis, Hospital Universitário de Londrina, Universidade Estadual de Londrina, Londrina, Paraná, Brazil

An optimized one-tube, semi-nested PCR assay for Paracoccidioides brasiliensis detection

INTRODUCTION Herein, we report a one-tube, semi-nested-polymerase chain reaction (OTsn-PCR) assay for the detection of Paracoccidioides brasiliensis. METHODS We developed the OTsn-PCR assay for the detection of P. brasiliensis in clinical specimens and compared it with other PCR methods. RESULTS The OTsn-PCR assay was positive for all clinical samples, and the detection limit was better or equivalent to the other nested or semi-nested PCR methods for P. brasiliensis detection. CONCLUSIONS The OTsn-PCR assay described in this paper has a detection limit similar to other reactions for the molecular detection of P. brasiliensis, but this approach is faster and less prone to contamination than other conventional nested or semi-nested PCR assays.

Efeitos comportamentais e imunológicos da fluoxetina em ratos submetidos ao nado forçado

Evidencias sugerem que a depressao envolve alteracoes imunologicas. No presente trabalho, os efeitos comportamentais e imunomoduladores de um antidepressivo, a fluoxetina, sao avaliados num modelo animal de depressao, o nado forcado. Nesse modelo, o comportamento de flutuar e usado como indice de desespero comportamental. Ratos foram tratados por 12 dias com fluoxetina ( 10mg/kg ) tres vezes ao dia ou com salina; e, nos mesmos dias, foram submetidos a sessoes de nado forcado. Adicionalmente, a resposta imune humoral a uma imunoestimulacao foi avaliada. Os animais tratados com fluoxetina apresentaram menor producao total de anticorpos e queda de massa corporal, alem d e passarem mais tempo flutua ndo. Os resultados sugerem que o desespero comportamental e a producao de anticorpos sao simultaneamente atenuados pela fluoxetina.

Phospholipase gene expression during Paracoccidioides brasiliensis morphological transition and infection

Phospholipase is an important virulence factor for pathogenic fungi. In this study, we demonstrate the following: (i) the Paracoccidioides brasiliensis pld gene is preferentially expressed in mycelium cells, (ii) the plb1 gene is mostly up-regulated by infection after 6 h of co-infection of MH-S cells or during BALB/c mice lung infection, (iii) during lung infection, plb1, plc and pld gene expression are significantly increased 6-48 h post-infection compared to 56 days after infection, strongly suggesting that phospholipases play a role in the early events of infection, but not during the chronic stages of pulmonary infection by P. brasiliensis.

Saccharomyces uvarum mannoproteins stimulate a humoral immune response in mice

Yeasts discarded in industrial processes can be used as a nutritional supplement and to extract cellular components with biotechnological aims. In this study, the humoral immune response of Swiss mice treated with mannoproteins (MP) from the yeast Saccharomyces uvarum was evaluated. The mice were treated with MPs at different doses and times and inoculated with 2% sheep red blood cells. An increase in total Ig in mice treated with 100 μg of MP at the time of immunization or 24 h before was observed in the primary immune response; in the secondary immune response, an increase was observed in total Ig values for all groups, and an increase of IgG was observed in the mice treated with MPs (100 μg) at the time of immunization or 24 h before. These results show that S. uvarum MPs present an immunostimulatory action on the humoral immune response in mice.

Accurate and sensitive real-time PCR assays using intergenic spacer 1 region to differentiate Cryptococcus gattii sensu lato and Cryptococcus neoformans sensu lato.

In this work, two accurate and sensitive real-time polymerase chain reaction (PCR) assays to differentiate pathogenic Cryptococcus gattii sensu lato (s.l.) and C. neoformans sensu lato (s.l.) targeting the intergenic spacer 1 (IGS1) region from rDNA locus were developed. Specific primers were designed based on their IGS1 sequence analyses and the optimal real-time PCR assays showed that the dissociation curves generated two different melting peaks, at 82.8 and 84.2ºC for C. gattii s.l. and C. neoformans s.l., respectively. No amplifications were observed in the negative template control. The minimum limit of detection of both primers was 100 plasmid copies per reaction, and they were highly specific when tested with a range of fungal DNAs. Overall, the results showed that the designed primers completely differentiated C. gattii s.l. and C. neoformans s.l. from clinical and environmental sources with great accuracy when compared to phenotypic identification, with no cross-reactivity to other fungal DNA.

Study of differential expression of miRNAs in lung tissue of mice submitted to experimental infection by Paracoccidioides brasiliensis

Abstract MicroRNAs (miRNAs) are small single stranded RNA sequences involved in post‐transcriptional regulation of different biological and physiological processes. Paracoccidioidomycosis (PCM) is an infection caused by Paracoccidioides brasiliensis, and it is a major cause of mortality due to systemic mycoses in Brazil. To date, there have been few reports on the role of miRNAs in the immune response against fungi, especially PCM. The objective of this study was to evaluate the differential expression of miRNAs related to the inflammatory response associated with pulmonary infection by P. brasiliensis. For this purpose, lungs from BALB/c mice, intravenously infected with P. brasiliensis (2.7×107 yeast cells/ml, n = 12) and noninfected BALB/c mice (n = 8), were collected at the 28 and 56 day after infection. The lung parenchyma presented a great number of yeast cells, granulomas, and edema at 28 days and a framework of resolution of the inflammatory process after 56 days. The mRNAs gata‐3, ror‐&ggr;t, foxp3, and IL‐6 were positively regulated at the moment at the 56 day, while the TGF‐&bgr;1 mRNA was positively regulated at both moments. The miRNAs 126a‐5p, 340‐5p, 30b‐5p, 19b‐3p, 221‐3p, 20a‐5p, 130a‐3p, and 301a‐3p, 466k presented the greatest increase in expression levels 28 days after infection, and the miRNAs let‐7f‐5p, let‐7a‐5p, 5p‐26b, let‐7e‐5p and 369‐3p, 466k presented a greater increase in levels of expression 56 days after infection. This study shows a set of differentially expressed miRNAs possibly involved in the immune response in mice during pulmonary infection by P. brasiliensis.

Evaluation of the Humoral Immune Response of Wistar Rats Submitted to Forced Swimming and Treated with Fluoxetine

The term stress was introduced into the biomedical field by Hans Selye (1936) in reference to a General Adaptation Syndrome which would consist of all non-specific systemic reactions that occur during an intense and chronic exposure to a stressor (e.g., pressure at work and poor diet). This syndrome would be different from the specific adaptive reactions (such as muscle hypertrophy caused by exercise performed on a regular basis) and immune responses (Selye, 1936).

Low Doses of Ochratoxin-A Decrease IgY and IgA Production in Broiler Chicks

The mycotoxin, ochratoxin-A (OTA), produced by some fungi, and is a natural contaminant of many foods and animal feeds worldwide. Due to its toxic effects, the recommended maximum daily intake of OTA for poultry feeds is 0.1 mg OTA/kg (ECR2006/575/EC); this dose does not induce changes in hepatic/renal parameters, but decreases thymus size and serum globulin concentrations. Accordingly, in this study, we assessed quantitatively the total circulating IgY and IgA serum levels, in chicks consuming a 0.1 mg OTA/kg diet (limit) and higher doses (0.3–1.1 mg OTA/kg diet) for 14 or 21 days. We also evaluated other immunological parameters (thymus, bursa of Fabricius, and spleen weights and leukocyte profiles) at day 21. Decreased IgY serum levels were observed in all OTA-treated groups (p < 0.05). In the low-dose group, IgA levels were decreased on day 21, but not on day 14. The size of the thymus and the bursa of Fabricius was decreased in all OTA-treated groups (p < 0.05), whereas reduced spleen size and altered leukocyte profiles were detected only in the high-dose group (p < 0.05). We concluded that chronic exposure to OTA, even at the recommended highest dose, affected IgY and IgA production in chicks.