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result(s) for
"Tobias, Fernando Luiz"
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Extracellular biosynthesis of silver nanoparticles using the cell-free filtrate of nematophagous fungus Duddingtonia flagrans
by
Tobias, Fernando Luiz
,
Pinto Oliveira, Jairo
,
Keijok, Wanderson Juvencio
in
Antimicrobial agents
,
Ascomycota
,
Biomass
2017
The biosynthesis of metallic nanoparticles (NPs) using biological systems such as fungi has evolved to become an important area of nanobiotechnology. Herein, we report for the first time the extracellular synthesis of highly stable silver NPs (AgNPs) using the nematophagous fungus
(AC001). The fungal cell-free filtrate was analyzed by the Bradford method and 3,5-dinitrosalicylic acid assay and used to synthesize the AgNPs in the presence of a 1 mM AgNO
solution. They have been characterized by UV-Vis spectroscopy, X-ray diffraction, transmission electron microscopy, dynamic light scattering, Zeta potential measurements, Fourier-transform infrared, and Raman spectroscopes. UV-Vis spectroscopy confirmed bioreduction, while X-ray diffractometry established the crystalline nature of the AgNPs. Dynamic light scattering and transmission electron microscopy images showed approximately 11, 38 nm monodisperse and quasispherical AgNPs. Zeta potential analysis was able to show a considerable stability of AgNPs. The N-H stretches in Fourier-transform infrared spectroscopy indicate the presence of protein molecules. The Raman bands suggest that chitinase was involved in the growth and stabilization of AgNPs, through the coating of the particles. Our results show that the NPs we synthesized have good stability, high yield, and monodispersion.
Journal Article
Control of Toxocara canis with Nematophagous Fungus: Perspective to Public Health
by
Hiura, Emy
,
Tobias, Fernando Luiz
,
Garcia Lopes, Aline Del Carmem
in
Letter to the Editor
,
Nematophagous fungi
,
Public health
2022
The article's abstract is not available.
Journal Article
Nematicidal activity of silver nanoparticles from the fungus Duddingtonia flagrans
by
Tobias, Fernando Luiz
,
Veloso, Francielle Bosi Rodrigues
,
Soares, Filippe Elias de Freitas
in
Animals
,
Anthelmintics - pharmacology
,
biological control
2019
Helminth parasites cause morbidity and mortality in both humans and animals. Most anthelmintic drugs used in the treatment of parasitic nematode infections act on target proteins or regulate the electrical activity of neurons and muscles. In this way, it can lead to paralysis, starvation, immune attack, and expulsion of the worm. However, current anthelmintics have some limitations that include a limited spectrum of activity across species and the threat of drug resistance, which highlights the need for new drugs for human and veterinary medicine.
Present study has been conducted to determine the anthelmintic activity of silver nanoparticles (AgNPs) synthesized from the extract of nematophagous fungus,
, on the infecting larvae of
(L
).
The nanoparticles were characterized by visual, ultraviolet, Fourier-transform infrared spectroscopy, transmission electron microscopy (TEM) analysis, and X-ray diffraction. The in vitro study was based on experiments to inhibit the motility of infective larvae (L
), and the ultrastructural analysis of the nematode was performed by images obtained by TEM.
The XRD studies revealed the crystalline nature of the nanoparticles, and FTIR results implied that AgNPs were successfully synthesized and capped with compounds present in the extract. The results showed that the green synthesis of AgNPs exhibited nematicidal activity, being the only ones capable of penetrating the cuticle of the larvae, causing changes in the tegmentum, and consequently, the death of the nematode.
The extract of the fungus
is able to synthesize AgNP and these have a nematicidal action.
Journal Article
A descriptive review of the use of organic acids and peracetic acid as a decontaminating strategy for meat
by
Rossi, Gabriel Augusto Marques
,
Mioni, Mateus de Souza Ribeiro
,
Tobias, Fernando Luiz
in
Bacteria
,
Beef
,
Contamination
2023
Meat can be a pathogen vehicle, and its spoilage contributes to food insecurity. Besides the importance of adopting good hygienic practices to avoid meat contamination, several decontaminating strategies have been studied. This review discusses the mechanisms of action of organic acids and peracetic acid, the factors that affect their efficacy, and compiles information about their microbiological and sensorial effects on meat. Factors that affect their efficacy include the species of microorganisms, the acid‐susceptibility within the same species, the initial contamination degree, the organic acid used and concentration, pH and volume of solutions, methods of application, contact time, steps of a flowchart where the treatment occurred and quantity of applications, site of carcass/meat treated and tissues composition, and combinations with other decontaminating treatments. Inspite of the amount of available data, the log reductions with their standard deviations and the temperature of solutions applied are rarely presented; and several studies lack information on the pH of the solutions. This strategy will be helpful for industries, contributing to enhanced food security and safety. However, studies for in loco validation must be performed before implementing these treatments. We provided extensive information of factors that affect the efficacy of organic and peracetic acids on meat decontamination. Rarely the log reductions and temperature of solutions are presented in the literature. Modifications on physico‐chemical and sensory aspects of meat do not appear to be worrisome. Organic acids and peracetic acid efficacy are a good strategy for meat decontamination, despite a wide variation in the results. In loco validation must be performed before implementing these treatments in industries.
Journal Article
Pathological aspects of disseminated protothecosis-like infection in a dog
by
Flecher, Mayra Cunha
,
Silva, Halana do Carmo
,
Tobias, Fernando Luiz
in
AGRONOMY
,
Algae
,
Animals
2024
Anatomopathological descriptions of infections caused by saprophytic algae in dogs are rare. This study reported the anatomopathological and microbiological findings suggestive of disseminated protothecosis in a dog residing in the state of Espírito Santo, Brazil. During necropsy, macroscopic alterations were observed in peripheral lymph nodes, heart, kidneys, pancreas, and lungs. Microbiological, cytological, and histopathological examinations were performed. Cytology and histopathology revealed piogranulomatous inflammation associated with sporangia and endospores, while microbiological culture suggested the growth of Prototheca spp.. These anatomopathological and microbiological findings were crucial for diagnosing and documenting the first case of disseminated Prototheca spp. compatible infection in a dog in the state of Espírito Santo, Brazil. RESUMO: Descrições anatomopatológicas de infecções causadas por algas saprófitas em cães são raras. Este estudo relata os achados anatomopatológicos e microbiológicos sugestivos de prototecose disseminada em um cão residente no estado do Espírito Santo, Brasil. Durante a necropsia foram observadas alterações macroscópicas em linfonodos periféricos, coração, rins, pâncreas e pulmões. Foram realizados exames microbiológicos, citológicos e histopatológicos. A citologia e a histopatologia revelaram inflamação piogranulomatosa associada a esporângios e endósporos, enquanto a cultura microbiológica sugeriu o crescimento de Prototheca spp. Esses achados anatomopatológicos e microbiológicos foram cruciais para diagnosticar e documentar o primeiro caso de infecção disseminada compatível com Prototheca spp.. estado do Espírito Santo, Brasil.
Journal Article
Feasibility of replacing the viral isolation technique in mice with RT-qPCR for the diagnosis of rabies
by
Magalhães Júnior, Cássio Alexandre Costa
,
Tobias, Fernando Luiz
,
Langoni, Hélio
in
AGRONOMY
,
Bats
,
Brain
2024
Rabies is a viral encephalitis that affects mammals, including humans. Rapid and effective laboratory diagnosis of the rabies virus is critical for public health. This study evaluated the operational, technical, and financial viability of the RT-qPCR in replacement of inoculation in mice for diagnosing rabies in the laboratory routine. A total of 316 samples of mammalian brains were analyzed, 121 positives and 195 negatives, previously diagnosed by direct immunofluorescence (DIF) and mouse inoculation test (MIT). The samples were submitted to the duplex TaqMan RT-qPCR technique. The accuracy, sensitivity, and specificity of RT-qPCR were analyzed. We analyzed the costs for performing the RT-qPCR technique and compared it with the cost of MIT. The results showed 99.37% accuracy, 99.17% sensitivity, and 99.49% specificity by RT-qPCR when related to DIF and MIT results, which proved to be a robust and repeatable technique. The minimum time for a positive diagnosis was reduced in RT-qPCR (1 day) if compared to MIT (9.64 days), with a 17.7% reduction in the cost of the molecular technique. The present study demonstrated that the molecular biology technique is an efficient tool to diagnose rabies in the laboratory routine, being able to replace MIT. RESUMO: A raiva é uma encefalite viral que acomete os mamíferos, incluindo humanos. O diagnóstico laboratorial rápido e eficaz do vírus da raiva é importante para a saúde pública. Este estudo teve como objetivo avaliar a viabilidade operacional, técnica e financeira da RT-qPCR em substituição à inoculação em camundongos para o diagnóstico da raiva na rotina laboratorial. Foram analisadas 316 amostras de cérebros de mamíferos, 121 positivas e 195 negativas, previamente diagnosticadas por imunofluorescência direta (IFD) e isolamento viral em camundongos, por inoculação intracerebral em camundongos. As amostras foram submetidas à técnica duplex TaqMan RT-qPCR. A precisão, sensibilidade e especificidade da RT-qPCR foram analisadas. Os custos para realizar a técnica de RT-qPCR foram analisados e comparados com o custo do isolamento viral em camundongos. Os resultados demostraram 99,37% de acurácia, 99,17% de sensibilidade e 99,49% de especificidade pela RT-qPCR quando relacionada aos resultados de IFD e isolamento viral em camundongos, que se mostrou uma técnica robusta e com repetibilidade. O tempo mínimo para diagnóstico positivo foi reduzido na RT-qPCR (1 dia) quando comparado ao isolamento viral em camundongos (9,64 dias), e com redução de 17,7% no custo pela técnica molecular. O presente estudo demonstrou que a técnica de biologia molecular é uma ferramenta eficiente para o diagnóstico da raiva na rotina laboratorial, podendo substituir o isolamento viral em camundongos.
Journal Article
Epidemiology and economic impact of bovine cysticercosis in the state of Espírito Santo, Brazil
by
Tobias, Fernando Luiz
,
Mathias, Luis Antonio
,
Veloso, Francielle Bosi Rodrigues
in
Abattoirs
,
AGRONOMY
,
Animals
2022
Bovine cysticercosis (BCC) is an important disease in Brazil due to its detection in abattoirs, resulting in economic losses for cattle farmers, and a public health corcern. Besides its importance, the knowledge about BCC epidemiology and impact remains not fully described in several areas in this country, requiring more studies. Thus, this study focused on establishing BCC prevalence in the regions and municipalities of the state of Espírito Santo from 2017 to 2019, establishing the associated risk factors, and estimating the economic losses for cattle farmers. A set of 2,330 cases of BCC was detected in the 407,529 bovine inspected by Federal Inspection Service (0.57%; C.I. 95% 0.55 - 0.60%) with a higher detection of unviable cysticercus (66.14%). The beef producers lost at least US $153,000.20 due to BCC through this period. The highest risk for BCC infection occurred in Metropolitana (OR = 9.19), Litoral Sul (OR = 7.77), Caparó (OR = 7.44), and Central Sul (OR = 7.19) mesoregions, respectively. The BCC was detected in animals from 67 municipalities and its prevalence increased in areas with high human population density (OR = 1.58;; p = 0.01). In conclusion, BCC is an important disease for beef production chain in the Brazilian state of Espírito Santo and a cause of economic losses, mainly in some areas, and urgently requires the adoption of prophylactic strategies to reduce the ocurrence of this parasite. RESUMO: A cisticercose bovina (CB) é uma doença importante no Brasil devido à sua detecção em abatedouros-frigoríficos que resulta em impactos econômicos aos criadores de bovinos, e um problema de saúde pública. Apesar da sua importância, o conhecimento sobre a sua epidemiologia e impacto persiste não completamente descritos em diversas áreas do país requer mais estudos. Portanto, esse estudo objetivou estabelecer a prevalência nos municípios e regiões do Estado do Espírito Santo de 2017 a 2019; estabelecer os fatores de risco associados; e estimar o impacto econômico aos pecuaristas. Durante o período, 2.330 casos de BC foram dectados entre os 407.529 bovinos inspecionados sob regime de inspeção federal (0,57%; I.C. 95% 0,55 - 0,60%), com maior frequência de cisticercos inviáveis (66,14%). Os pecuaristas perderam pelo menos US$ 153.000,20 devido à ocorrência de CB durante o período. As áreas de maior risco para a enfermidade nesse estado estão nas mesoregiões Metropolitana (OR = 9,19), Litoral Sul (OR = 7,77), Caparó (OR = 7,44), e Central Sul (OR = 7,19), respectivamente. A doença foi detectada em animais de 67 municípios e a prevalência da enfermidade foi maior em áreas com elevada densidade populacional humana (OR = 1,58; p = 0,01). Assim, conclui-se que a CB é uma importante doença para a cadeia da carne bovina no estado, além de uma importante causa de perdas econômicas, principalmente em algumas áreas, e necessita, urgentemente, da adoação de medidas profiláticas para reduzir a ocorrência desse parasita.
Journal Article
Silver Nanoparticles from Duddingtonia flagrans: Evaluation of Potential Ovicidal Activity on Toxocara canis Eggs
by
Tobias, Fernando Luiz
,
Langoni, Helio
,
Comério, Lara Coslop
in
Animals
,
Assaying
,
biological control
2024
The filtrate of the nematophagous fungus Duddingtonia flagrans produces silver nanoparticles (AgNPs) with nematicidal potential. However, there are currently no reports of its activity against Toxocara canis eggs. The aim of this study was to investigate the potential ovicidal activity of AgNPs–D. flagrans on T. canis eggs. T. canis eggs were obtained from the dissection of the uterus of adult female nematodes. After the biosynthesis of AgNPs, two experimental assays (A and B) were performed. In assay A, the ovicidal activity of AgNPs on eggs was evaluated after 15 and 30 days of interaction. In assay B, the inhibition (development) of the eggs was measured after 30 days of interaction. The results of assay A showed that the AgNPs destroyed an average of 47% of the eggs tested by the end of the experiment, causing significant structural damage. In assay B, an inhibition rate of 88% was observed at the end of 30 days. The results of the ovicidal activity of AgNP–D. flagrans were promising and indicate the potential for future studies on these biomolecules with ovicidal properties.
Journal Article
Antibodies against Bovine herpesvirus 1 in dairy herds in the state of Espirito Santo, Brasil
by
Tobias, Fernando Luiz
,
Santos, Marcos Antônio dos
,
Santos, Marcus Rebouças
in
AGRICULTURE, MULTIDISCIPLINARY
,
BoHV-1
,
Espírito Santo
2014
Bovine herpesvirus 1 (BoHV-1) causes major losses in worldwide livestock, affecting the respiratory and reproductive tracts of bovine. In the past decades, the number of cases in Brazil has been gradually increasing. Therefore, it is important to assess the distribution of infection in different regions of the country. In the state of Espírito Santo (ES) the BoHV 1 infection rate in dairy cattle herds is unknown. Thus, the aim of this study was to detect neutralizing antibodies against BoHV-1 in serum samples from 1,161 non-vaccinated cows from 59 dairy cattle herds in 23 municipalities of the Metropolitan, North, Northwest and South macro-regions. The identification of seropositive cows was evaluated by the virus neutralization test. The results showed that of all serum samples evaluated 775 (66.75%) had neutralizing antibodies against BoHV-1. Moreover, all herds were found positive; however, the percentage of positive cows varied among regions; 49.06%, 62.15%, 67.21% and 80.04% for the Metropolitan, South, North and Northwest macro-regions, respectively. In this study, the results clearly indicate the dissemination of the viral agent in dairy cattle in the ES state, requiring the monitoring and control of diseases related to BoHV-1 infection. O herpesvírus bovino 1 (Bovine herpesvirus 1 - BoHV-1) causa grandes prejuízos econômicos à pecuária bovina mundial, por comprometer os sistemas respiratório e reprodutivo de bovinos de corte e leiteiros. Nas últimas décadas, os registros de casos clínicos ocasionados pelo BoHV-1, no Brasil, mostram que têm aumentado gradualmente, o que torna importante o delineamento de estudos que mostrem a distribuição da infecção nas diversas regiões do país. O objetivo deste estudo foi investigar a frequência de anticorpos anti-BoHV-1 em rebanhos bovinos leiteiros do Estado do Espírito Santo (ES), região ainda carente de informações sobre a distribuição desse patógeno. Para o estudo, foram utilizadas amostras de soro de bovinos leiteiros, não vacinados contra o BoHV-1, de 1.161 animais, provenientes de 59 rebanhos, oriundos de 23 municípios pertencentes às macrorregiões metropolitana, norte, noroeste e sul do ES. Para a identificação de animais soropositivos, foi aplicada a técnica de vírus-neutralização em microplacas. Das amostras de soros avaliadas, 775 (66,75%) apresentaram anticorpos neutralizantes contra BoHV-1, sendo todos os rebanhos considerados positivos. As percentagens das frequências de animais positivos foram bastante variadas, apresentando 49,06, 62,15, 67,21 e 80,04%, para as macrorregiões metropolitana, sul, norte e noroeste, respectivamente. Neste estudo, os resultados claramente indicam a circulação do agente viral no rebanho bovino leiteiro do ES, sendo necessário o controle e monitoramento das enfermidades relacionadas com o BoHV-1.
Journal Article
Feasibility of replacing the viral isolation technique in mice with RT-qPCR for the diagnosis of rabies/Viabilidade da substituicao da tecnica de isolamento viral em camundongos pela RT-qPCR para o diagnostico da raiva
2024
Rabies is a viral encephalitis that affects mammals, including humans. Rapid and effective laboratory diagnosis of the rabies virus is critical for public health. This study evaluated the operational, technical, and financial viability of the RT-qPCR in replacement of inoculation in mice for diagnosing rabies in the laboratory routine. A total of 316 samples of mammalian brains were analyzed, 121 positives and 195 negatives, previously diagnosed by direct immunofluorescence (DIF) and mouse inoculation test (MIT). The samples were submitted to the duplex TaqMan RT-qPCR technique. The accuracy, sensitivity, and specificity of RT-qPCR were analyzed. We analyzed the costs for performing the RT-qPCR technique and compared it with the cost of MIT. The results showed 99.37% accuracy, 99.17% sensitivity, and 99.49% specificity by RT-qPCR when related to DIF and MIT results, which proved to be a robust and repeatable technique. The minimum time for a positive diagnosis was reduced in RT-qPCR (1 day) if compared to MIT (9.64 days), with a 17.7% reduction in the cost of the molecular technique. The present study demonstrated that the molecular biology technique is an efficient tool to diagnose rabies in the laboratory routine, being able to replace MIT. Key words: laboratory diagnosis, molecular techniques, one health, viruses, zoonosis. A raiva é uma encefalite virai que acomete os mamíferos, incluindo humanos. O diagnóstico laboratorial rápido e eficaz do vírus da raiva é importante para a saúde pública. Este estudo teve como objetivo avaliar a viabilidade operacional, técnica e financeira da RT-qPCR em substituição à inoculação em camundongos para o diagnóstico da raiva na rotina laboratorial. Foram analisadas 316 amostras de cérebros de mamíferos, 121 positivas e 195 negativas, previamente diagnosticadas por imunofluorescência direta (IFD) e isolamento virai em camundongos, por inoculação intracerebral em camundongos. As amostras foram submetidas à técnica duplex TaqMan RT-qPCR. A precisão, sensibilidade e especificidade da RT-qPCR foram analisadas. Os custos para realizar a técnica de RT-qPCR foram analisados e comparados com o custo do isolamento virai em camundongos. Os resultados demostraram 99,37% de acurácia, 99,17% de sensibilidade e 99,49% de especificidade pela RT-qPCR quando relacionada aos resultados de IFD e isolamento virai em camundongos, que se mostrou uma técnica robusta e com repetibilidade. O tempo mínimo para diagnóstico positivo foi reduzido na RT-qPCR (1 dia) quando comparado ao isolamento virai em camundongos (9,64 dias), e com redução de 17,7% no custo pela técnica molecular. O presente estudo demonstrou que a técnica de biologia molecular é uma ferramenta eficiente para o diagnóstico da raiva na rotina laboratorial, podendo substituir o isolamento virai em camundongos. Palavras-chave: diagnóstico laboratorial, técnicas moleculares, saúde única, vírus, zoonose.
Journal Article