AVALIAÇÃO DO USO DE RADIAÇÃO ULTRAVIOLETA DO TIPO C PARA A DESINFECÇÃO MICROBIANA E VIRAL

Emerging as an alternative to manual cleaning and disinfection methods, devices that use ultraviolet C (UVC) light present evidence capable of inactivating a wide spectrum of microorganisms such as bacteria, fungi and viruses. The aim of this study was to evaluate the effectiveness of UVC radiation in microbial and viral disinfection. For this, an experimental study was carried out using a cleaning squeegee composed of two 30 W mercury lamps for sterilization at a distance of 60 mm from the floor. For the antimicrobial evaluation assay, strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were grown on plates containing Mueler Hinton agar and subjected to different doses of UVC radiation (0 mJ/cm², 17.5 mJ/cm², 31.2 mJ/cm², 62.4 mJ/cm² and 175.5 mJ/cm²). For the antiviral evaluation assay, clinical samples with a positive result in RT-qPCR for SARS-CoV-2 were used in and in this case, each sterile plate that contained only these samples received a dose of UVC radiation equal to 0 mJ/cm², 19, 5 mJ/cm², 58.5 mJ/cm², 117.0 mJ/cm² and 175.0 mJ/cm², respectively. In the culture of E. coli there was no growth of the bacteria in any of the doses tested. In the culture of S. aureus, there was the growth of colonies in the dosages of 17.5 mJ/cm² and 31.2 mJ/cm². On the plates containing P. aeruginosa, there was growth at all doses evaluated, with a decrease in the number of colonies along the exposures. As for the viral results, a decrease in viral load can be observed. The use of the squeegee with UVC radiation was effective in disinfecting the bacteria and viruses tested.Surgindo como uma alternativa aos métodos de limpeza e desinfecção manuais, os dispositivos que utilizam luz ultravioleta C (UVC) apresentam evidências capazes de inativar um amplo espectro de micro-organismos como bactérias, fungos e vírus. O objetivo desse estudo foi avaliar a eficácia da radiação UVC na desinfecção microbiana e viral. Para isso, foi realizado um estudo experimental utilizando um rodo de limpeza composto de duas lâmpadas de mercúrio de 30 W para esterilização a uma distância de 60 mm do chão.  Para o ensaio de avaliação antimicrobiana, foram utilizadas cepas de Staphylococcus aureus, Escherichia coli e Pseudomonas aeruginosa cultivadas em placas contendo ágar Mueler Hinton sendo submetidas à diferentes doses de radiação UVC (0 mJ/cm², 17,5 mJ/cm², 31,2 mJ/cm², 62,4 mJ/cm² e 175,5 mJ/cm²). Para o ensaio de avaliação antiviral, foram utilizadas amostras clínicas com resultado positivo na RT-qPCR para o SARS-CoV-2 e nesse caso, placas estéreis que continham apenas essas amostras receberam uma dose de radiação UVC igual a 0 mJ/cm², 19,5 mJ/cm², 58,5 mJ/cm², 117,0 mJ/cm² e 175,0 mJ/cm², respectivamente. Na cultura de E. coli não houve crescimento da bactéria em nenhuma das dosagens testadas. Na cultura de S. aureus, houve o crescimento de colônias nas dosagens de 17,5 mJ/cm² e 31,2 mJ/cm². Já nas placas contendo P. aeruginosa houve crescimento em todas as dosagens avaliadas, com diminuição do número de colônias ao longo das exposições. Quanto aos resultados virais, pode-se observar uma diminuição da carga viral. A utilização do rodo com radiação UVC foi eficaz na desinfecção das bactérias e vírus testados

Sazonalidade da avifauna no campus Carreiros da Fundação Universidade Federal do Rio Grande, Rio Grande do Sul, Brasil

Neste estudo foram estabelecidas a composição específica e a sazonalidade da ocorrência das aves na área do Campus Carreiros da Fundação Universidade Federal do Rio Grande (FURG), Rio Grande, RS. Para isso foram realizadas saídas de campo entre maio de 1999 e agosto de 2005. Em média, 15 observações foram realizadas a cada estação do ano e pelo menos uma seção mensal de captura com redes de neblina, a partir de novembro de 2003. A área foi percorrida de modo a amostrar os diferentes tipos de ambientes existentes no local. A identificação das espécies foi feita por análise visual ou do canto. Ao longo deste período foi registrada uma riqueza de 120 espécies de aves, das quais 79 ocorreram no outono, 80 no inverno, 84 na primavera e 89 no verão. Os maiores valores foram verificados na primavera e verão e são devidos à presença de espécies migratórias na área, mas a riqueza foi similar ao longo do ano. Os resultados sugerem que o desenho paisagístico e a posição do Campus, próximo ao estuário da Laguna dos Patos, Praia do Cassino entre outras, favorece a riqueza observada. Este espaço, portanto é um importante recurso para pesquisa e utilização didática, devido às facilidades logísticas. Os resultados também poderão auxiliar em decisões sobre áreas a serem futuramente impactadas com obras de infra-estrutura

Birds seasonality at the Campus Carreiros, Fundação Universidade Federal do Rio Grande, Rio Grande do Sul, Brazil

Submitted by Franciele Cruz ([email protected]) on 2010-09-30T14:00:49Z No. of bitstreams: 1 Sazonalidade da avifauna no Campus Carreiros da Fundação Universidade Federal do Rio Grande, RS, Brasil.pdf: 49134 bytes, checksum: 023025d941f7d577a82613a6e16a1492 (MD5)Approved for entry into archive by Helena Moraes([email protected]) on 2010-09-30T21:20:06Z (GMT) No. of bitstreams: 1 Sazonalidade da avifauna no Campus Carreiros da Fundação Universidade Federal do Rio Grande, RS, Brasil.pdf: 49134 bytes, checksum: 023025d941f7d577a82613a6e16a1492 (MD5)Made available in DSpace on 2010-09-30T21:20:06Z (GMT). No. of bitstreams: 1 Sazonalidade da avifauna no Campus Carreiros da Fundação Universidade Federal do Rio Grande, RS, Brasil.pdf: 49134 bytes, checksum: 023025d941f7d577a82613a6e16a1492 (MD5) Previous issue date: 2006Neste estudo foram estabelecidas a composição específica e a sazonalidade da ocorrência das aves na área do Campus Carreiros da Fundação Universidade Federal do Rio Grande (FURG), Rio Grande, RS. Para isso foram realizadas saídas de campo entre maio de 1999 e agosto de 2005. Em média, 15 observações foram realizadas a cada estação do ano e pelo menos uma seção mensal de captura com redes de neblina, a partir de novembro de 2003. A área foi percorrida de modo a amostrar os diferentes tipos de ambientes existentes no local. A identificação das espécies foi feita por análise visual ou do canto. Ao longo deste período foi registrada uma riqueza de 120 espécies de aves, das quais 79 ocorreram no outono, 80 no inverno, 84 na primavera e 89 no verão. Os maiores valores foram verificados na primavera e verão e são devidos à presença de espécies migratórias na área, mas a riqueza foi similar ao longo do ano. Os resultados sugerem que o desenho paisagístico e a posição do Campus, próximo ao estuário da Laguna dos Patos, Praia do Cassino entre outras, favorece a riqueza observada. Este espaço, portanto é um importante recurso para pesquisa e utilização didática, devido às facilidades logísticas. Os resultados também poderão auxiliar em decisões sobre áreas a serem futuramente impactadas com obras de infra-estrutura

Photodynamic action of Benzo[a]pyrene in K562 Cells

Benzo[a]pyrene (BaP) is ubiquitously distributed in the environment, being considered the most phototoxic element among polycyclic aromatic hydrocarbon (PAHs). In presence of oxygen, PAHs can act as a photosensitizer by means of promoting photo-oxidation of biological molecules (photodynamic action, PDA). Thus, the present study analyzed the photodynamic action of BaP under UVA irradiation (BaP + UVA) and its oxidative effects on K562 cells. The evaluation of BaP kinetics showed that the highest intracellular concentration occurred after 18 h of incubation. Cell viability, reactive oxygen species (ROS) generation, lipid peroxidation, DNA damage (breaks and DNA–protein cross-link [DNAPC]) were assessed after exposure to BaP, UVA and BaP plus UVA irradiation (BaP + UVA). Cell viability was decreased just after exposure to BaP + UVA. Lipid peroxidation and DNA breaks increased after BaP + UVA exposure, while the DNAPC increased after BaP, UVA and BaP + UVA exposure, suggesting that BaP + UVA effects were a consequence of both type II (producing mainly singlet oxygen) and type I (producing others ROS) mechanisms of PDA

Antimycobacterial and cytotoxicity activity of microcystins. Journal of venomous animals and toxins including tropical diseases

Background: The present work aimed to evaluate the antimycobacterial activity and cytotoxicity of Microcystis aeruginosa toxins, the MC-LR variant and purified extract of [D-Leu1 ] microcystin-LR. Methods: The antimicrobial activity of M. aeruginosa extract and microcystin was evaluated by resazurin microtiter assay against Mycobacterium tuberculosis, M. terrae, M. chelonae and M. kansasii. The cytotoxicity assay was performed by trypan blue exclusion against the HTC cell line. Results: Antimicrobial activity was observed in the hexanic extract of M. aeruginosa (RST 9501 strain) against M. tuberculosis, including sensitive and resistant strains with minimal inhibitory concentrations (MIC) between 1.93 μM and 0.06 μM. The high activity of M. aeruginosa hexanic extract could be attributed to the major presence of the toxins MC-LR and [D-Leu1 ] MC-LR that showed activity at MIC between 53 and 0.42 μM against tested mycobacterial strains. Even at the highest concentration tested, no toxicity of M. aeruginosa extracts was identified against HTC cells. Conclusions: These preliminary results suggest that [D-Leu1 ] MC-LR is a promising candidate for the development of a new antimycobacterial agen

Nitric oxide-dependent pigment migration induced by ultraviolet radiation in retinal pigment cells of the crab neohelice granulata

The purpose of this study was to verify the occurrence of pigment dispersion in retinal pigment cells exposed to UVA and UVB radiation, and to investigate the possible participation of a nitric oxide (NO) pathway. Retinal pigment cells from Neohelice granulata were obtained by cellular dissociation. Cells were analyzed for 30 min in the dark (control) and then exposed to 1.1 and 3.3 J cm)2 UVA, 0.07 and 0.9 J cm)2 UVB, 20 nM b-PDH (pigment dispersing hormone) or 10 lM SIN-1 (NO donor). Histological analyses were performed to verify the UV effect in vivo. Cultured cells were exposed to 250 lM L-NAME (NO synthase blocker) and afterwards were treated with UVA, UVB or b-PDH. The retinal cells in culture displayed significant pigment dispersion in response to UVA, UVB and b-PDH. The same responses to UVA and UVB were observed in vivo. SIN-1 did not induce pigment dispersion in the cell cultures. L-NAME significantly decreased the pigment dispersion induced by UVA and UVB but not by b-PDH. All retinal cells showed an immunopositive reaction against neuronal nitric oxide synthases.Therefore, UVA and UVB radiation are capable of inducing pigment dispersion in retinal pigment cells of Neohelice granulata and this dispersion may be nitric oxide synthase dependent

Toxicity mechanisms of onion (Allium cepa) extracts and compounds in multidrug resistant erythroleukemic cell line

Onion (Allium cepa) is being studied as a potential anticancer agent, but little is known regarding its effect in multidrug resistance (MDR) cells. In this work, the cytotoxicity of crude onion extract (OE) and fractioned extract (aqueous, methanolic and ethyl acetate), as well as some onion compounds (quercetin and propyl disulfide) were evaluated in Lucena MDR human erythroleukemic and its K562 parental cell line. The capacity of OE to induce apoptosis and/or necrosis in these cells, the possible participation of oxidative stress and DNA damage were also assessed. Similar sensitivities were obtained for both tumoral cells, however only OE caused significant effects in the cells. In K562 cells, a significant increase of apoptosis was verified while the Lucena cells experienced a significant increase of necrosis. An antioxidant capacity was verified for OE discarding oxidative damage. However, OE provoked similar significant DNA damage in both cell lines. Thus, the OE capacity to overcome the MDR phenotype suggests anti-MDR action of OE

Antioxidant properties of the mucus secreted by Laeonereis acuta (Polychaeta, Nereididae): a defense against environmental pro-oxidants?

Polychaeta species like Laeonereis acuta (Nereididae) usually secrete great amounts of mucus that wrap the animal inside. Taking into account that fungi action in the sediment and UV radiation acting on dissolved organic matter in the water produces reactive oxygen species (ROS) like hydrogen peroxide (H2O2), it was considered that the mucus secretion could represent an antioxidant defense against environmental ROS. Antioxidant enzymes (catalase—CAT; superoxide dismutase—SOD; glutathione peroxidase—GPx and glutathione-S-transferase—GST) and total antioxidant capacity (TOSC) were determined in worms and mucus secretion. Higher (pb0.05) CAT, GPx and TOSC values were registered in mucus samples respect worms, SOD activity was similar (pN0.05) in both kind of samples, and absence of GST activity was observed in mucus samples, suggesting absence of catalyzed phase II reactions. In assays conducted with hepatoma cell lines exposed to H2O2, it was verified that:(1) mucus co-exposure significantly (pb0.05) lowered DNA damage induced by H2O2; (2) ROS production was significantly (pb0.05) reduced when cells were exposed simultaneously with mucus samples and H2O2 respect H2O2 alone. It can be concluded that the mucus production contributes substantially to the antioxidant defense system of the worm against environmental ROS through the interception or degradation of H2O2, peroxyl and hydroxyl radicals

Infrared radiation influence on molt and regeneration of neohelice granulata dana, 1851 (Grapsidae, Sesarminae)

This paper analyzes the influence of infrared radiation (IR) on regeneration, after autotomy of limb buds of Neohelice granulata and consequently the time molt. Eyestalks were ablated to synchronize the start of molt. Afterward, animals were autotomized of five pereopods and divided into control and irradiated groups. The irradiated group was treated for 30 min daily until molt. Limb buds from five animals of days 4, 16 and 20 were collected and histological sections were made from them. These sections were photographed and chitin and epithelium content measured. Another group was made, and after 15 days limb buds were extracted to analyze mitochondrial enzymatic activity from complex I and II. The irradiated group showed a significant reduction in molt time (19.38 ± 1.22 days) compared with the control group (32.69 ± 1.57 days) and also a significant increase in mitochondrial complex I (388.9 ± 27.94%) and II (175.63 ± 7.66%) in the irradiated group when compared with the control group (100 ± 17.90; 100 ± 7.82, respectively). However, these effects were not acompanied by histological alterations in relation to chitin and epithelium. This way, it was possible to demonstrate that IR increases complex I and II activity, reduces the time molt and consequently increases the appendage regeneration rate

Sensitivity to microcystins: a comparative study in human cell lines with and without multidrug resistance phenotype

Multidrug resistance (MDR) is an obstacle in cancer treatment. An understanding of how tumoral cells react to oxidants can help us elucidate the cellular mechanism involved in resistance. Microcystins are cyanobacteria hepatotoxins known to generate oxidative stress. The aim of this study was to compare the sensitivity to microcystins of human tumoral cell lines with (Lucena) and without (K562) MDR phenotype. Endpoints analyzed were effective microcystins concentration to 50% of exposed cells (EC50), antioxidant enzyme activity, lipid peroxidation, DNA damage, reactive oxygen species (ROS) concentration, and tubulin content. Lucena were more resistant and showed lower DNA damage than K562 cells (P < 0.05). Although microcystins did not alter catalase activity, a higher mean value was observed in Lucena than in K562 cells. Lucena cells also showed lower ROS concentration and higher tubulin content. The highe metabolism associated with the MDR phenotype should increase ROS concentration and make for an improved antioxidant defense against the toxic effects of icrocystins