Oxidative stress caused by lead in the lichen Xanthoria parietina

The assessment of the air quality is a major concern to the current time. The monitoring and maintenance of air quality necessarily pass by detecting and estimating the overall air pollution. The use of lichens must be an assessmenttool to be studied. In our work we were interested about the toxicity of lead on the various parameters of stress in the lichen Xanthoria parietina. For this purpose, lichen thalli have been incubated at lead concentrations of 0, 0.5, 1.0, 5.0 and 10.0 mM, for time scale of 0, 24, 48 and 96 hours. The obtained results showed that lead has an action on the various studied parameters, and the intensity of oxidative stress observed in lichens thalli depends on the concentration, and time of exposure. Lead induced a decrease in chlorophyll and protein contents, and an increase in the contents of catalase, hydrogen peroxide and reduced glutathione. Furthermore, the results also showed that high concentrations of lead caused total destruction of reduced glutathione.(AU)

Gas exchange and growth of soursop under salt stress and H2O2 application methods / Trocas gasosas e crescimento de graviola sob estresse salino e métodos de aplicação de H2O2

The production of soursop seedlings in the Northeast region of Brazil has faced limitations due to the high concentrations of salts in the water, so it is necessary to use techniques that enable its cultivation, and the application of hydrogen peroxide to minimize the deleterious effects of salt stress stands out. In this context, the objective was to evaluate forms of application of hydrogen peroxide as an attenuator of salt stress on the gas exchange and growth of soursop seedlings cv. Morada Nova. The experiment was conducted under greenhouse conditions, in an Regolithic Neosol of sandy loam texture, from the municipality of Lagoa Seca - PB. A completely randomized design was used in a 5 × 4 factorial arrangement, whose treatments resulted from the combination of five levels of electrical conductivity of irrigation water - ECw (0.6 - control, 1.2, 1.8, 2.4 and 3.0 dS m-1) and four forms of hydrogen peroxide application (M1 - without H2O2 application, M2 - application by seed soaking, M3 - application by foliar spraying, and M4 - application by seed soaking + foliar spraying), with four replicates and two plants per experimental unit, totaling 160 plants. The concentration of H2O2 used in the different forms of application was 20 µM. Irrigation water salinity from 0.6 dS m-1 reduced the gas exchange and growth of soursop. The method of H2O2 application by foliar spraying minimized the effects of salt stress on gas exchange. The method of H2O2 application by seed soaking reduced the effect of salt stress on the growth of soursop at 85 days after sowing.

A produção de mudas de gravioleira na região semiárida do Brasil tem enfrentado limitações devido às elevadas concentrações de sais nas águas, sendo necessário o uso de técnicas que viabilizem seu cultivo, destacando-se a aplicação do peróxido de hidrogênio. Neste contexto, objetivou-se avaliar as formas de aplicação do peróxido de hidrogênio como atenuante do estresse salino nas trocas gasosas e no crescimento de mudas de gravioleira cv. Morada Nova. O estudo foi conduzido sob condições de casa de vegetação, em um Neossolo Regolítico de textura franco-arenosa, utilizando-se o delineamento inteiramente casualizado, no arranjo fatorial 5 × 4, cujos tratamentos resultaram da combinação de cinco níveis de condutividade elétrica da água de irrigação - CEa (0,6 - testemunha; 1,2; 1,8; 2,4 e 3,0 dS m-1) e quatro formas de aplicação de peróxido de hidrogênio (M1- sem aplicação de H2O2, M2 - aplicação via embebição das sementes, M3 -aplicação por pulverização foliar e M4 - aplicação via embebição das sementes + pulverização foliar), com quatro repetições e duas plantas por unidade experimental, perfazendo o total de 160 plantas. A concentração de H2O2 utilizada nas diferentes formas de aplicação foi de 20 µM. A salinidade da água de irrigação a partir de 0,6 dS m-1 diminuiu as trocas gasosas e o crescimento das plantas de gravioleira. O método de aplicação do H2O2 via pulverização foliar minimizou o efeito do estresse salino sobre as trocas gasosas. O método de aplicação do H2O2 via embebição das sementes diminuiu o estresse salino no crescimento de gravioleira aos 85 dias após o semeio.

Potential of indigenous plants seed extracts of Anisophyllea boehmii and Aframomum sanguineum from Burundi to protect against oil oxidation / Potencial de extratos de sementes em plantas indígenas de Anisophyllea boehmii e Aframomum sanguineum do Burundi para a proteção contra a oxidação de óleo

The objective of seed extracts from Anisophyllea boehmii and Aframomum sanguineum were to evaluate their ability to stabilize against oxidation of oils exposed to sunlight on one hand and subjected to high temperatures on the other hand. Determination of the peroxide value (PV) showed that the extracts had reduced the oxidation of sunflower oils. After 8 weeks of sunlight exposure, the concentration of 265.45 mg/l of A. boehmii extract showed a PV of 30.78 meq O2/kg, 67.4 mg/l extract of A. sanguineum had a PV of 42.75 meq O2/kg while the oils without extracts had a very high PV (125.06 meq O2/kg). Heating of the oils to 180°C for 8 hours was found, with A. boehmii extract (265.45 mg/l), to have a PV of 29.66 meq O2/kg, with that of A. sanguineum, while the PV of the oils without extract reached 50.66 meq O2/kg. In the light of these results, the seeds of A. boehmii and A. sanguineum contain antioxydant compounds, which, once extracted, can be used for many purposes in the food processing, pharmaceutical and cosmetic industries.

O objetivo da extração de sementes de Anisophyllea boehmii e Aframomum sanguineum foi avaliar sua capacidade de estabilização contra a oxidação de óleos expostos à luz solar, por um lado, e submetidos a altas temperaturas, por outro. A determinação do valor de peróxido (VP) mostrou que os extratos tinham reduzido a oxidação dos óleos de girassol. Após 8 semanas de exposição à luz solar, a concentração de 265,45 mg/l de extrato de A. boehmii mostrou um VP de 30,78 ppm O2/kg, 67,4 mg/l de extrato de A. sanguineum tinha um VP de 42,75 ppm O2/kg enquanto os óleos sem extratos tinham um VP muito alto (125,06 ppm O2/kg). Aquecimento dos óleos a 180 °C por 8 horas foi obtido com extrato de A. boehmii (265,45 mg/l), para obtenção de um VP de 29,66 ppm O2/kg, com o de A. sanguineum, enquanto o VP dos óleos sem extrato atingiu 50,66 ppm O2/kg. A partir desses resultados, pode-se afirmar que as sementes de A. boehmii e A. sanguineum contêm compostos antioxidantes que, uma vez extraídos, podem ser utilizados para diversos fins nas indústrias de processamento de alimentos, farmacêutica e cosmética.

Bacillus licheniformis SMIA-2 protease used as an additive in detergent formulations

Microbial proteases, especially from Bacillus spp., have been widely exploited for a broad variety of applications, such as the improvement of the cleaning efficiency of conventional detergents. In this work, the statistical design of the experiment was used to optimize the concentrations of a three-component mixture: Bacillus licheniformis SMIA-2 protease, Linear Alkylbenzene Sulphate and hydrogen peroxide, in an attempt to prepare an environmentally correct cleaning formulation. The results demonstrated that the combination of 1% (w/v) protease with 1.5% (w/v) LAS and 1% (w/v) H2O2 was effective in removing blood from cloth pieces and that a protease concentration decrease from 1.0% to 0.5% (w/v) would not have a signi&64257;cant impact on percent blood removal if LAS concentrations between 1.5-2.0% (w/v) in combination with lower (<0.5%, w/v) concentrations of H2O2 were used. Thus, the protease from Bacillus licheniformis SMIA-2 can be effectively incorporated into cleaning formulations together with LAS and hydrogen peroxide to formulate more sustainable detergents.

Bacillus licheniformis SMIA-2 protease used as an additive in detergent formulations

Microbial proteases, especially from Bacillus spp., have been widely exploited for a broad variety of applications, such as the improvement of the cleaning efficiency of conventional detergents. In this work, the statistical design of the experiment was used to optimize the concentrations of a three-component mixture: Bacillus licheniformis SMIA-2 protease, Linear Alkylbenzene Sulphate and hydrogen peroxide, in an attempt to prepare an environmentally correct cleaning formulation. The results demonstrated that the combination of 1% (w/v) protease with 1.5% (w/v) LAS and 1% (w/v) H2O2 was effective in removing blood from cloth pieces and that a protease concentration decrease from 1.0% to 0.5% (w/v) would not have a signi&64257;cant impact on percent blood removal if LAS concentrations between 1.5-2.0% (w/v) in combination with lower (<0.5%, w/v) concentrations of H2O2 were used. Thus, the protease from Bacillus licheniformis SMIA-2 can be effectively incorporated into cleaning formulations together with LAS and hydrogen peroxide to formulate more sustainable detergents.(AU)

Foliar application of H2O2 as salt stress attenuator in 'BRS Rubi do Cerrado' sour passion fruit / Aplicação foliar de H2O2 como atenuante do estresse salino em maracujazeiro-azedo 'BRS Rubi do Cerrado'

Irrigation with saline water causes a reduction in yield, especially in semi-arid regions. Cultivation strategies have been developed to mitigate salt stress on plants, such as the use of hydrogen peroxide. The objective of this study was to evaluate the attenuating effect of hydrogen peroxide on the gas exchange and growth of 'BRS Rubi do Cerrado' sour passion fruit cultivated under irrigation with saline water. The design was completely randomized in split-plot plots, with water salinity levels ECw (0.6, 1.2, 1.8, 2.4, and 3.0 dS m-1) considered the plots and the concentrations of hydrogen peroxide H2O2 (0, 15, 30, and 45 µM) considered the subplots, with three replicates. Gas exchange (stomatal conductance, transpiration, CO2 assimilation rate, intercellular CO2 concentration, instantaneous water use efficiency, and instantaneous carboxylation efficiency), and absolute and relative growth rates in stem diameter were evaluated. An increase in irrigation water salinity from 0.6 dS m-1 reduced gas exchange, and exogenous application of hydrogen peroxide did not promote a significant effect on gas exchange. However, foliar application of hydrogen peroxide at 15 µM increased the growth of 'BRS Rubi do Cerrado' sour passion fruit.(AU)

A irrigação com águas salinas causa redução na produtividade, principalmente nas regiões semiáridas. Estratégias de cultivo vêm sendo desenvolvidas, a exemplo uso de peróxido de hidrogênio para mitigar o estresse salino sobre as plantas. Objetivou-se avaliar o efeito atenuante do peróxido de hidrogênio sobre as trocas gasosas e o crescimento do maracujazeiro-azedo 'BRS Rubi do Cerrado' cultivado sob irrigação com águas salinas. O delineamento foi inteiramente casualizados em parcelas subdivididas, sendo os níveis de salinidade da água - CEa (0,6, 1,2, 1,8, 2,4 e 3,0 dS m-1) consideradas as parcelas, e as concentrações de peróxido de hidrogênio ­ H2O2 (0, 15, 30 e 45 µM) as subparcelas, com três repetições. Foram avaliadas as trocas gasosas (condutância estomática, transpiração, taxa de assimilação de CO2, concentração intercelular de CO2, eficiência instantânea no uso da água e eficiência instantânea de carboxilação), e a taxa de crescimento absoluto e relativo do caule. O aumento na salinidade da água de irrigação a partir da salinidade de 0,6 dS m-1 reduziu as trocas gasosas; a aplicação exógena de peróxido de hidrogênio não promoveu efeito significativos sob as trocas gasosas. A aplicação foliar de 15 µM de peróxido de hidrogênio aumentou o crescimento do maracujazeiro-azedo 'BRS Rubi do Cerrado'.(AU)

Oxidative stress and antioxidant defense in detoxification systems of snake venom-induced toxicity

Snakebites remain a major life-threatening event worldwide. It is still difficult to make a positive identification of snake species by clinicians in both Western medicine and Chinese medicine. The main reason for this is a shortage of diagnostic biomarkers and lack of knowledge about pathways of venom-induced toxicity. In traditional Chinese medicine, snakebites are considered to be treated with wind, fire, and wind-fire toxin, but additional studies are required. Methods: Cases of snakebite seen at the Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine were grouped as follows: fire toxin - including four cases of bites by Agkistrodon acutus and three bites by Trimeresurus stejnegeri - and wind-fire toxin - four cases of bites by vipers and three bites by cobras. Serum protein quantification was performed using LC-MS/MS. Differential abundance proteins (DAPs) were identified from comparison of snakebites of each snake species and healthy controls. The protein interaction network was constructed using STITCH database. Results: Principal component analysis and hierarchical clustering of 474 unique proteins exhibited protein expression profiles of wind-fire toxins that are distinct from that of fire toxins. Ninety-three DAPs were identified in each snakebite subgroup as compared with healthy control, of which 38 proteins were found to have significantly different expression levels and 55 proteins displayed no expression in one subgroup, by subgroup comparison. GO analysis revealed that the DAPs participated in bicarbonate/oxygen transport and hydrogen peroxide catabolic process, and affected carbon-oxygen lyase activity and heme binding. Thirty DAPs directly or indirectly acted on hydrogen peroxide in the interaction network of proteins and drug compounds. The network was clustered into four groups: lipid metabolism and transport; IGF-mediated growth; oxygen transport; and innate immunity. Conclusions: Our results show that the pathways of snake venom-induced toxicity may form a protein network of antioxidant defense by regulating oxidative stress through interaction with hydrogen peroxide.(AU)

Oxidative stress and antioxidant defense in detoxification systems of snake venom-induced toxicity

Snakebites remain a major life-threatening event worldwide. It is still difficult to make a positive identification of snake species by clinicians in both Western medicine and Chinese medicine. The main reason for this is a shortage of diagnostic biomarkers and lack of knowledge about pathways of venom-induced toxicity. In traditional Chinese medicine, snakebites are considered to be treated with wind, fire, and wind-fire toxin, but additional studies are required. Methods: Cases of snakebite seen at the Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine were grouped as follows: fire toxin - including four cases of bites by Agkistrodon acutus and three bites by Trimeresurus stejnegeri - and wind-fire toxin - four cases of bites by vipers and three bites by cobras. Serum protein quantification was performed using LC-MS/MS. Differential abundance proteins (DAPs) were identified from comparison of snakebites of each snake species and healthy controls. The protein interaction network was constructed using STITCH database. Results: Principal component analysis and hierarchical clustering of 474 unique proteins exhibited protein expression profiles of wind-fire toxins that are distinct from that of fire toxins. Ninety-three DAPs were identified in each snakebite subgroup as compared with healthy control, of which 38 proteins were found to have significantly different expression levels and 55 proteins displayed no expression in one subgroup, by subgroup comparison. GO analysis revealed that the DAPs participated in bicarbonate/oxygen transport and hydrogen peroxide catabolic process, and affected carbon-oxygen lyase activity and heme binding. Thirty DAPs directly or indirectly acted on hydrogen peroxide in the interaction network of proteins and drug compounds. The network was clustered into four groups: lipid metabolism and transport; IGF-mediated growth; oxygen transport; and innate immunity. Conclusions: Our results show that the pathways of snake venom-induced toxicity may form a protein network of antioxidant defense by regulating oxidative stress through interaction with hydrogen peroxide.(AU)

Budburst and flowering intensity by the spraying of dormancy-breaking products in 'Eva' apple trees / Brotação e intensidade de floração pela aplicação de indutores de brotação em macieiras 'Eva'

Spraying of dormancy-breaking chemicals is a mandatory procedure to produce temperate fruits in low-chill regions. Although hydrogen cyanamide (HC) + mineral oil (MO) show efficiency enhancing budburst, the usage of HC is restricted in some countries due to its toxicity. Therefore, this research aimed to evaluate the efficiency of spraying different dormancy-breaking agents on ‘Eva apple tree buds, under the conditions of the Depressão Central of Rio Grande do Sul, Brazil. Different doses of Erger® (0, 2, 3, 4, 5%) + 3% Ca(NO3)2 were tested and compared with MO (4%) or MO (4%) + HC (0.6%). Budburst rate of apical and axillary buds, physiological alterations in buds, return bloom, yield and fruit weight were evaluated. Erger® treatments efficiently enhanced budburst, with a result equivalent to HC + MO treatment. The budburst rate increased as the Erger® dose increased, also causing the increment of the return bloom in the following year. However, doses of 4 and 5% caused the death of shoots. The activity of the peroxidases and the content of H2O2 in the buds were affected by the treatments. Yield and fruit mass were different in response to treatments, although the effect varied between years. Erger® + Ca(NO3)2 spraying increase budburst in apical and axillary buds of ‘Eva apple tree in low-chill conditions and doses up to 3% of the commercial product do not cause toxicity.(AU)

A aplicação de indutores de brotação é uma prática fundamental para a produção de frutíferas temperadas em regiões com menor quantidade de horas de frio. Apesar de cianamida hidrogena (CH) + óleo mineral (OM) apresentarem eficiência na indução da brotação de gemas de macieira, a toxicidade de CH ao aplicador resultou em restrições ao seu uso em alguns países. Assim, o objetivo do trabalho foi avaliar a eficiência da aplicação de diferentes indutores de brotação de gemas na macieira ‘Eva, nas condições da Depressão Central do RS. Testaram-se diferentes doses de Erger® (0, 2, 3, 4, 5%) + 3% Ca(NO3)2, comparados com OM (4%) ou OM (4%) + CH (0,6%). Foram avaliados a taxa de brotação de gemas apicais e axilares, alterações fisiológicas nas gemas, o retorno floral, a produção e a massa dos frutos. Os tratamentos de Erger® foram eficientes em aumentar a brotação de gemas, com resultados equivalentes ao tratamento CH + OM. A taxa de brotação de gemas aumentou em resposta ao aumento na dose de Erger®, provocando também incremento no retorno floral no ano seguinte, no entanto doses de 4 e 5% provocaram morte de ramos. A atividade de peroxidases e os teores de peróxidos de hidrogênio nas gemas apicais foram afetadas pelos tratamentos. A produção e a massa média dos frutos diferiram entre tratamentos, porém o efeito variou entre as safras. A aplicação de Erger® + Ca(NO3)2 aumenta a brotação de gemas apicais e axilares em macieiras ‘Eva em condição de baixo acúmulo de frio e doses de até 3% do produto comercial não causam toxidez.(AU)

Budburst and flowering intensity by the spraying of dormancy-breaking products in 'Eva' apple trees / Brotação e intensidade de floração pela aplicação de indutores de brotação em macieiras 'Eva'

Spraying of dormancy-breaking chemicals is a mandatory procedure to produce temperate fruits in low-chill regions. Although hydrogen cyanamide (HC) + mineral oil (MO) show efficiency enhancing budburst, the usage of HC is restricted in some countries due to its toxicity. Therefore, this research aimed to evaluate the efficiency of spraying different dormancy-breaking agents on ‘Eva’ apple tree buds, under the conditions of the Depressão Central of Rio Grande do Sul, Brazil. Different doses of Erger® (0, 2, 3, 4, 5%) + 3% Ca(NO3)2 were tested and compared with MO (4%) or MO (4%) + HC (0.6%). Budburst rate of apical and axillary buds, physiological alterations in buds, return bloom, yield and fruit weight were evaluated. Erger® treatments efficiently enhanced budburst, with a result equivalent to HC + MO treatment. The budburst rate increased as the Erger® dose increased, also causing the increment of the return bloom in the following year. However, doses of 4 and 5% caused the death of shoots. The activity of the peroxidases and the content of H2O2 in the buds were affected by the treatments. Yield and fruit mass were different in response to treatments, although the effect varied between years. Erger® + Ca(NO3)2 spraying increase budburst in apical and axillary buds of ‘Eva’ apple tree in low-chill conditions and doses up to 3% of the commercial product do not cause toxicity.

A aplicação de indutores de brotação é uma prática fundamental para a produção de frutíferas temperadas em regiões com menor quantidade de horas de frio. Apesar de cianamida hidrogena (CH) + óleo mineral (OM) apresentarem eficiência na indução da brotação de gemas de macieira, a toxicidade de CH ao aplicador resultou em restrições ao seu uso em alguns países. Assim, o objetivo do trabalho foi avaliar a eficiência da aplicação de diferentes indutores de brotação de gemas na macieira ‘Eva’, nas condições da Depressão Central do RS. Testaram-se diferentes doses de Erger® (0, 2, 3, 4, 5%) + 3% Ca(NO3)2, comparados com OM (4%) ou OM (4%) + CH (0,6%). Foram avaliados a taxa de brotação de gemas apicais e axilares, alterações fisiológicas nas gemas, o retorno floral, a produção e a massa dos frutos. Os tratamentos de Erger® foram eficientes em aumentar a brotação de gemas, com resultados equivalentes ao tratamento CH + OM. A taxa de brotação de gemas aumentou em resposta ao aumento na dose de Erger®, provocando também incremento no retorno floral no ano seguinte, no entanto doses de 4 e 5% provocaram morte de ramos. A atividade de peroxidases e os teores de peróxidos de hidrogênio nas gemas apicais foram afetadas pelos tratamentos. A produção e a massa média dos frutos diferiram entre tratamentos, porém o efeito variou entre as safras. A aplicação de Erger® + Ca(NO3)2 aumenta a brotação de gemas apicais e axilares em macieiras ‘Eva’ em condição de baixo acúmulo de frio e doses de até 3% do produto comercial não causam toxidez.

Comparison of the efficacy of hydrogen peroxide and salt for control of fungal infections on brown trout (Salmo trutta) eggs

Background: Fungal infections can cause serious problems infecting fish eggs, especially unfertilized or dead eggs. In the past, this problem was solved by using very effective chemicals such as malachite green and formalin. But, due to its toxicity and carcinogenicity, malachite green was banned for use in fish intended for human consumption. Formalin also has been banned in most countries. Chemicals and drugs recommended for use to treat fungal infections are hydrogen peroxide, salt, potassium permanganate etc. The goal of the present study was to determine and compare the efficacy of antifungal effects of hydrogen peroxide and sodium chloride on brown trout eggs.Materials, Methods & Results: The experiment was conducted in the brown trout hatchery, Šipovo, Bosnia and Herzegovina. The experimental groups contained 500 and 1,000 mg/L of hydrogen peroxide with 15 and 30 min of exposition; 1 and 2.5% of sodium chloride with 15 and 30 min of exposition and a negative control group (no chemical treatment). The treatment concentrations were calculated and prepared from hydrogen peroxide of 35% active ingredient, and sodium chloride (sterilized) of 100% active ingredient. Eggs for the study were spawned from 11 females and 4 males. The first treatment was performed on the fourth day, and each next treatment was performed at 3-day intervals. Six treatments were administered until the 19th day after the fertilization. The treatment of the eggs was provided until the eggs reached the eyed stage. The effectiveness of the chemical treatments was measured by a hatch rate. There was a significant difference between all treated groups and the negative control group (P < 0.05). Hydrogen peroxide with a concentration of 500 mg/L for 30 min was the most effective and demonstrated a higher hatching rate (75.7%). Sodium chloride treatments resulted in statistically significantly lower hatching rates than hydrogen peroxide treatments.[...]

Comparison of the efficacy of hydrogen peroxide and salt for control of fungal infections on brown trout (Salmo trutta) eggs

Background: Fungal infections can cause serious problems infecting fish eggs, especially unfertilized or dead eggs. In the past, this problem was solved by using very effective chemicals such as malachite green and formalin. But, due to its toxicity and carcinogenicity, malachite green was banned for use in fish intended for human consumption. Formalin also has been banned in most countries. Chemicals and drugs recommended for use to treat fungal infections are hydrogen peroxide, salt, potassium permanganate etc. The goal of the present study was to determine and compare the efficacy of antifungal effects of hydrogen peroxide and sodium chloride on brown trout eggs.Materials, Methods & Results: The experiment was conducted in the brown trout hatchery, Šipovo, Bosnia and Herzegovina. The experimental groups contained 500 and 1,000 mg/L of hydrogen peroxide with 15 and 30 min of exposition; 1 and 2.5% of sodium chloride with 15 and 30 min of exposition and a negative control group (no chemical treatment). The treatment concentrations were calculated and prepared from hydrogen peroxide of 35% active ingredient, and sodium chloride (sterilized) of 100% active ingredient. Eggs for the study were spawned from 11 females and 4 males. The first treatment was performed on the fourth day, and each next treatment was performed at 3-day intervals. Six treatments were administered until the 19th day after the fertilization. The treatment of the eggs was provided until the eggs reached the eyed stage. The effectiveness of the chemical treatments was measured by a hatch rate. There was a significant difference between all treated groups and the negative control group (P < 0.05). Hydrogen peroxide with a concentration of 500 mg/L for 30 min was the most effective and demonstrated a higher hatching rate (75.7%). Sodium chloride treatments resulted in statistically significantly lower hatching rates than hydrogen peroxide treatments.[...](AU)

Heterologous expression of a rice metallothionein isoform (OsMTI-1b) in Saccharomyces cerevisiae enhances cadmium, hydrogen peroxide and ethanol tolerance

Metallothioneins are a superfamily of low-molecular-weight, cysteine (Cys)-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. The main purpose of this study was to investigate the effect of heterologous expression of a rice metallothionein isoform (OsMTI-1b) on the tolerance of Saccharomyces cerevisiae to Cd2+, H2O2 and ethanol stress. The gene encoding OsMTI-1b was cloned into p426GPD as a yeast expression vector. The new construct was transformed to competent cells of S. cerevisiae. After verification of heterologous expression of OsMTI-1b, the new strain and control were grown under stress conditions. In comparison to control strain, the transformed S. cerevisiae cells expressing OsMTI-1b showed more tolerance to Cd2+ and accumulated more Cd2+ ions when they were grown in the medium containing CdCl2. In addition, the heterologous expression of GST-OsMTI-1b conferred H2O2 and ethanol tolerance to S. cerevisiae cells. The results indicate that heterologous expression of plant MT isoforms can enhance the tolerance of S. cerevisiae to multiple stresses.(AU)

EFEITO DO GÁS OZÔNIO E DO ÓLEO DE GIRASSOL OZONIZADO NO CRESCIMENTO IN VITRO DO Pythium insidiosum CANINO

A pitiose é uma doença infecciosa granulomatosa causada pelo oomiceto aquático Pythium insidiosum. Trata-se de uma infecção crônica responsável por graves danos locais e sistêmicos. Os tratamentos convencionais possuem eficácia reduzida. Assim, a busca por terapias alternativas se faz necessária para o devido combate da doença. Neste contexto, o ozônio (O3) tem apresentado alto poder antimicrobiano frente a patógenos diversos, como fungos e bactérias. Assim, o presente estudo teve por objetivo caracterizar o efeito do gás ozônio e do óleo de girassol ozonizado no crescimento in vitro do P. insidiosum isolado de cães. No Experimento 1, o patógeno foi exposto à mistura gasosa O2-O3 por períodos distintos (72 g O3 mL-1 durante 5, 15 ou 30 minutos) ou com diferentes concentrações por 30 minutos (32, 52 ou 72 gO3 mL-1 ). No Experimento 2, fragmentos de P. insidiosum foram recobertos com óleos de girassol ozonizados com índice de peróxido distintos (25, entre 400 e 500 ou 600 mmolequiv. kg-1 ). As amostras foram cultivas em Ágar Sabouraud Dextrose durante os primeiros 14 dias pós-tratamento ao logo dos quais, a área de crescimento foi mensurada digitalmente. Amostras que não apresentaram crescimento nesses foram recultivadas para avaliar a ação germicida ou germiostática do respectivo tratamento. No Experimento 1, a exposição do P. insidiosum ao gás O3 por 30 minutos apresentou ação germicida independente da concentração utilizada. Todavia, amostras do patógeno expostas ao gás O3 por tempos inferiores (15 ou 05 min) apresentaram taxa de crescimento semelhante ao grupo controle (P>0,1). No Experimento 2, o óleo de girassol ozonizado com índice de peróxido ou 600 mmol-equiv. kg-1 foi o único a inibir o crescimento do patógeno. Frente as condições experimentais do presente estudo, conclui-se que a exposição à mistura gasosa O2-O3 durante 30 minutos e ao óleo de girassol com alto índice de peróxido apresentam ação germicida frente ao P. insidiosum isolado de cães.

Pythiosis is an infectious granulomatous disease caused by the aquatic oomycete Pythium insidiosum. Conventional treatments have reduced effectiveness against the chronic infection, which can be responsible for local and systemic damage in several species. In this context, ozone (O3) has shown high antimicrobial action against several pathogens, such as fungi and bacteria. Threfore, the present study aimed to characterize the effect of O3 gas and ozonated sunflower oil on the in vitro growth of P. insidiosum isolated from dogs. In Experiment 1, the pathogen was exposed to the O2-O3 gas mixture for different periods (72 g O3 mL-1 for 5, 15 or 30 minutes) or with different concentrations (32, 52 or 72 gO3 mL-1 for 30 minutes). In Experiment 2, fragments of P. insidiosum were covered with ozonized sunflower oils with different peroxide index (25, between 400 and 500 or 600 mmol-equiv. Kg-1 ). The growth area of the pathogen was digitally measured during the first 14 days post-treatment. Samples with absence of grow were recultured to assess the germicidal or germiostatic action of the respective treatment. In Experiment 1, exposure of P. insidiosum to O3 gas for 30 minutes showed germicidal action regardless of the concentration. However, samples of the pathogen exposed to O3 gas for 15 or 05 min showed similar growth rate when compared to the control group (P> 0.1). In Experiment 2, ozonized sunflower oil with a peroxide index 600 mmolequiv. kg-1 inhibit the growth of the pathogen. Considering the experimental conditions of the present study, the treatment with O2-O3 gas mixture for 30 minutes or sunflower oil with a high peroxide index have a germicidal action against P. insidiosum isolated from dogs.

Esterilização química para o cultivo in vitro de porta-enxerto de pessegueiro / Chemical sterilization of in vitro culture for peach rootstook

A esterilização dos meios de cultura é normalmente realizada por autoclavagem. Decorre que, este processo pode degradar ou reduzir a ação de compostos com efeito fisiológico desejável, como vitaminas e fitorreguladores. Objetivou-se avaliar a ação de agentes esterilizantes adicionados ao meio de cultura para o estabelecimento in vitro de umezeiro ‘Rigitano’. Para tanto, segmentos nodais foram inoculados em meio de cultura MS, preparado considerando os seguintes tratamentos: adição de hipoclorito de sódio (0,01 e 0,05% v/v); de dióxido de cloro (0,1; 0,5 e 1,0 % v/v); e de peróxido de hidrogênio (0,3; 0,7 e 1,5% v/v). O tratamento controle constou da ausência de agente esterilizante, autoclavado e não autoclavado. Em períodos variáveis de avaliação (7, 14 e 21 dias), foram determinadas sobrevivência dos explantes, contaminação total, contaminação por bactéria, contaminação por fungos e oxidação. Constatou-se a ocorrência de fungos dos gêneros Alternaria, Cladosporium, Penicillium, Trichoderma e Criptococcus. Podese concluir que o uso de peróxido de hidrogênio ou dióxido de cloro é eficiente para a esterilização química de meios de cultivo.

The culture media sterilization is typically performed by autoclaving. However, this process may degrade or reduce the action of compounds with desired physiological effect, such as vitamins and growth regulators. This study aimed to evaluate the effect of sterilizing agents added to the culture medium in vitro mume 'Rigitano' establishment. For this purpose, nodal segments were inoculated into culture medium prepared considering the following treatments: addition of sodium hypochlorite (0.01 and 0.05 % v/v), chlorine dioxide (0.1, 0.5 and 1% v/v) or hydrogen peroxide (0.3, 0.7 and 1.5 %, v/v). The control treatment consisted of the absence of sterilizing, autoclaved and non-autoclaved. In different periods (7, 14 and 21 days), it was determined survival explants, whole contamination, contamination by bacteria, fungi contamination and oxidation. It was found ocurrence of Alternaria, Cladosporim, Penicillium, Trichoderma and Cryptococcus fungal genera. It was conclude that the use of hydrogen peroxide or chlorine dioxide is effective for the chemical sterilization of culture media.

Esterilização química para o cultivo in vitro de porta-enxerto de pessegueiro / Chemical sterilization of in vitro culture for peach rootstook

A esterilização dos meios de cultura é normalmente realizada por autoclavagem. Decorre que, este processo pode degradar ou reduzir a ação de compostos com efeito fisiológico desejável, como vitaminas e fitorreguladores. Objetivou-se avaliar a ação de agentes esterilizantes adicionados ao meio de cultura para o estabelecimento in vitro de umezeiro ‘Rigitano. Para tanto, segmentos nodais foram inoculados em meio de cultura MS, preparado considerando os seguintes tratamentos: adição de hipoclorito de sódio (0,01 e 0,05% v/v); de dióxido de cloro (0,1; 0,5 e 1,0 % v/v); e de peróxido de hidrogênio (0,3; 0,7 e 1,5% v/v). O tratamento controle constou da ausência de agente esterilizante, autoclavado e não autoclavado. Em períodos variáveis de avaliação (7, 14 e 21 dias), foram determinadas sobrevivência dos explantes, contaminação total, contaminação por bactéria, contaminação por fungos e oxidação. Constatou-se a ocorrência de fungos dos gêneros Alternaria, Cladosporium, Penicillium, Trichoderma e Criptococcus. Podese concluir que o uso de peróxido de hidrogênio ou dióxido de cloro é eficiente para a esterilização química de meios de cultivo.(AU)

The culture media sterilization is typically performed by autoclaving. However, this process may degrade or reduce the action of compounds with desired physiological effect, such as vitamins and growth regulators. This study aimed to evaluate the effect of sterilizing agents added to the culture medium in vitro mume 'Rigitano' establishment. For this purpose, nodal segments were inoculated into culture medium prepared considering the following treatments: addition of sodium hypochlorite (0.01 and 0.05 % v/v), chlorine dioxide (0.1, 0.5 and 1% v/v) or hydrogen peroxide (0.3, 0.7 and 1.5 %, v/v). The control treatment consisted of the absence of sterilizing, autoclaved and non-autoclaved. In different periods (7, 14 and 21 days), it was determined survival explants, whole contamination, contamination by bacteria, fungi contamination and oxidation. It was found ocurrence of Alternaria, Cladosporim, Penicillium, Trichoderma and Cryptococcus fungal genera. It was conclude that the use of hydrogen peroxide or chlorine dioxide is effective for the chemical sterilization of culture media.(AU)

Fontes de Minerias orgânicos e inorgânicos sobre a oxidação lipídica em pet food

Minerais orgânicos ou quelatados, desenvolvidos tecnologicamente em sua forma complexada a outras moléculas (aminoácidos ou peptídeos), vêm sendo estudados por sua melhor disponibilidade em relação a fontes inorgânicas. Contudo, os efeitos de fontes de minerais orgânicos na oxidação lipídica durante a extrusão ainda são pouco conhecidos. Portanto, o objetivo deste estudo foi comparar as fontes de minerais (inorgânicas e/ou orgânicas) na oxidação lipídica em alimentos extrusados para gatos adultos, durante a extrusão e shelf-life de pet food. Para tal, foram formuladas 5 tratamentos, sendo uma dieta controle, e dietas suplementadas com dois níveis das fontes inorgânicas e orgânicas dos minerais Ferro, Cobre e Zinco. Tais tratamentos foram analisados com relação às concentrações de ácidos graxos e residuais de antioxidante durante a extrusão e shelf-life das rações, índice de peróxido, atividade de água e umidade durante o armazenamento. O teste de palatabilidade durante a shelf-life foi realizado para verificar a percepção organolética dos gatos frente a alimentos com diferentes fontes de minerais. Observou-se reduções significavas dos ácidos graxos palmítico (16:0), oleíco (18:1n9); linoleíco (18:2n6), linolênico (18:3n3) e araquidônico (20:4n6) durante a extrusão, bem como a redução na concentração de antioxidantes sintéticos de 49,72%; 35,04%; 38,56%, 33,61% e 33,14% para os tratamentos controle, MI-1, MI-2, MO-1 e MO- 2. Durante a vida de prateleira, os níveis de metais de transição afetaram a estabilidade oxidativa. O índice de peróxido para as dietas suplementadas com a fonte orgânica tendeu a crescimento menos acentuado quando comparado a fonte inorgânica. A atividade de água aumentou durante a estocagem das rações, seguindo o comportamento da umidade. Houve preferência pela dieta suplementada com minerais orgânicas, no início e com 360 dias de armazenamento, quando comparada à dieta controle e às dietas com minerais inorgânicos nos dias 90 e 360 de shelf-life. Conclui-se que o processo de extrusão causa alterações oxidativas significativas em pet food e que esta não é influenciada pela fonte ou níveis dos metais de transição cobre, ferro e zinco. Durante a vida de prateleira, os níveis de metais de transição afetam a estabilidade oxidativa dos alimentos que pode ser controlada parcialmente pelo uso de fontes orgânicas de minerais.

Organic or chelated minerals, technologically developed in their form complexed to other molecules (amino acids or peptides), have been studied due to their better availability in relation to inorganic sources. However, the effects of organic mineral sources on lipid oxidation during extrusion are still little known. Therefore, the aim of this study was to compare minerals sources (inorganic and/or organic) in lipid oxidation in extruded foods for adult cats, during extrusion and shelf-life of pet food. For this, 5 treatments were formulated, being a control diet, and diets supplemented with two levels of inorganic and organic sources of Iron, Copper and Zinc minerals. These treatments were analysed in relation to the concentrations of fatty acids and antioxidant residuals during extrusion and shelf-life of the diets, peroxide index, water activity and humidity during storage. The palatability test during shelf-life was performed to verify the organoleptic perception of cats in food with different mineral sources. There were significant reductions in palmitic fatty acids (16:0), oleic (18:1n9); linoleic (18:2n6), linolenic (18:3n3) and arachidonic (20:4n6) during extrusion, as well as a reduction in the concentration of synthetic antioxidants of 49.72%; 35.04%; 38.56%, 33.61% and 33.14% for control, MI-1, MI2, MO-1 and MO-2 treatments. During shelf-life, the transition of metal levels affected the oxidative stability. The peroxide index for diets supplemented with organic source tended to have a less pronounced growth when compared to inorganic source. Water activity increased during shelf-life, following humidity behaviour. There was preference for diet supplemented with organic minerals, at the beginning and with 360 days of storage, when compared to the control diet and diets with inorganic minerals on the 90th and 360th of shelf-life. It was concluded that the extrusion process causes significant oxidative changes in pet food and that it was not influenced by source or levels of the metals copper, iron and zinc transition. During shelf-life, the transition of metal levels affected the oxidative stability of food, which can be partially controlled by the use of organic mineral sources.

EFEITO DO ÓLEO DE GIRASSOL OZONIZADO NA QUEBRA DE BIOFILME IN VITRO PRODUZIDO POR BACTÉRIAS ISOLADAS DO ÚTERO DE ÉGUAS SUSCETÍVEIS

Em éguas com endometrite infecciosa crônica, os microrganismos podem dificultar o diagnóstico e tratamento, levando ao uso indiscriminado de antibióticos, resultando no aumento da resistência antimicrobiana, geralmente associada à formação de biofilme. A ozonioterapia pode ser uma opção terapêutica da endomentrite, devido aos seus efeitos bactericidas e antiinflamatórios. O objetivo desse estudo foi realizar a identificação e perfil de sensibilidade/resistência a antimicrobianos, produção de biofilme de bactérias isoladas do útero de éguas e avaliar o efeito do óleo de girassol ozonizado na quebra de biofilme in vitro. Amostras de 41 éguas com histórico de subfertilidade foram coletadas. Para cultura bacteriana foram armazenadas em caldo BHI e para cultura fúngica em solução de NaCl a 0,9%, encaminhadas refrigeradas para o LABRAPE-UFRPE. As amostras foram submetidas à cultura e identificação e, posteriormente, ao teste de sensibilidade in vitro, e a produção de biofilme foi avaliada pelo método de cristal violeta. Bactérias formadoras de biofilme foram submetidas à ação do óleo de girassol ozonizado, em concentrações pré-determinadas por MIC e MBC. Foi observado isolamento microbiológico em 75,6% (31/41) das amostras. Sendo 25,8% (8/31) Staphylococcus spp.; 12,9% (4/31) bacilos Gram-negativos não fermentadores de lactose; 3,22% (1/31) Streptococcus -hemolítico; 3,22% (1/31) E. coli; 3,22% (1/31) Klebsiella spp. e 3,22% (1/31) Proteus spp.; 22,6% (7/31) das amostras apresentaram Bacillus spp. e Micrococcus spp em 6,45% (2/31). Dentre as amostras isoladas com fungos 6,45% (2/31) foram positivas para Cladosporium spp. Observou-se ainda 12,9% (4/31) presença de infecção mista, (Klebsiella spp. e E. colli - 1/31) (Staphylococcus spp. e Penicilium spp. 1/31), (Staphylococcus spp. e Cladosporium spp. 1/31) e (Klebsiella spp. e Trichosporon spp. 1/31). Quanto ao perfil de sensibilidade, 95,23% apresentaram sensibilidade para Amicacina; 90,47% para Gentamicina, Enrofloxacina, Tetraciclina e Ceftriaxona e 80,95% para Azitromicina. Em relação ao perfil de resistência, 95,24% das amostras resistentes a penicilina, e 100% das bactérias Gram-negativas resistentes e 70% para Ampicilina. Dos 21 isolados bacterianos submetidos à produção de biofilme 76,2% (16/21) apresentaram produção positiva, sendo 43,75% (7/16) fracas produtoras; 43,75% (7/16) moderadas produtoras e 12,5% (2/16) fortes produtoras, com uma média de massa de biofilme de 0,145 (0,328±0,066) paras os cocos Gram-positivos e 0,155 (0,307±0,077) para os bacilos Gram-negativos. Após a ação do Óleo de Girassol Ozonizado na concentração de 203,43 mEq/L foi observada redução na massa de biofilme dos bacilos Gram-negativos para 0,109 (0,054 ± 0,210). Pode-se concluir que a endometrite bacteriana foi mais prevalente nesse estudo, no entanto, alguns casos com presença de desenvolvimento de infecção fúngica concomitante. Os macrolídeos se mostraram efetivos contra os agentes testados e os -Lactâmicos inviáveis principalmente para endometrites por bactérias Gram-negativas. O Óleo de Girassol Ozonizado apresentou resultados favoráveis para quebra de biofilme de bactérias Gram negativas.

In mares with chronic infectious endometritis, microorganisms can make diagnosis and treatment difficult, leading to the indiscriminate use of antibiotics, resulting in increased antimicrobial resistance, usually associated with the formation of biofilm. Ozone therapy can be a therapeutic option for endomentritis, due to its bactericidal and anti-inflammatory effects. The aim of this study was to perform the identification and profile of sensitivity / resistance to antimicrobials, biofilm production of bacteria isolated from the uterus of mares and to evaluate the effect of ozonized sunflower oil on the breakdown of biofilm in vitro. Samples from 41 mares with a history of subfertility were collected. For bacterial culture they were stored in BHI broth and for fungal culture in 0.9% NaCl solution, sent refrigerated to LABRAPE-UFRPE. The samples were subjected to culture and identification and, subsequently, to the in vitro sensitivity test, and the biofilm production was evaluated by the violet crystal method. Biofilm-forming bacteria were subjected to the action of ozonated sunflower oil, in concentrations predetermined by MIC and MBC. Microbiological isolation was observed in 75.6% (31/41) of the samples. 25.8% (8/31) Staphylococcus spp .; 12.9% (4/31) non-lactose fermenting Gram negative bacilli; 3.22% (1/31) -hemolytic streptococcus; 3.22% (1/31) E. coli; 3.22% (1/31) Klebsiella spp. and 3.22% (1/31) Proteus spp .; 22.6% (7/31) of the samples presented Bacillus spp. and Micrococcus spp in 6.45% (2/31). Among the samples isolated with 6.45% (2/31) fungi were positive for Cladosporium spp. It was also observed 12.9% (4/31) presence of mixed infection, (Klebsiella spp. And E. coli - 1/31) (Staphylococcus spp. and Penicilium spp. 1/31), (Staphylococcus spp. and Cladosporium spp. - 1/31) and (Klebsiella spp. and Trichosporon spp. 1/31). As for the sensitivity profile, 95.23% had sensitivity to Amikacin; 90.47% for Gentamicin, Enrofloxacin, Tetracycline and Ceftriaxone and 80.95% for Azithromycin. Regarding the resistance profile, 95.24% of the samples resistant to penicillin, and 100% of gram-negative resistant bacteria and 70% to Ampicillin. Of the 21 bacterial isolates submitted to biofilm production, 76.2% (16/21) showed positive production, with 43.75% (7/16) being poor producers; 43.75% (7/16) moderate producers and 12.5% (2/16) strong producers, with an average biofilm mass of 0.145 (0.328 ± 0.066) for Gram positive coconuts and 0.155 (0.307 ± 0.077) for Gram Negative bacilli. After the action of Ozonized Sunflower Oil at a concentration of 203.43 mEq / L, a reduction in the biofilm mass of Gram negative bacilli was observed to 0.109 (0.054 ± 0.210). It can be concluded that bacterial endometritis was more prevalent in this study, however, some cases with the presence of concomitant fungal infection. Macrolides were effective against the tested agents and -Lactamics were not viable mainly for Gram-negative bacteria endometritis. Ozonized Sunflower Oil showed favorable results for the breakdown of Gram negative bacteria biofilm.

Preservatives and neutralizing substances in milk: analytical sensitivity of official specific and nonspecific tests, microbial inhibition effect, and residue persistence in milk / Sustâncias conservantes e neutralizantes no leite: sensibilidade analítica das provas oficiais específicas, provas inespecíficas, inibição microbiana e persistência de resíduos no leite

Milk fraud has been a recurring problem in Brazil; thus, it is important to know the effect of most frequently used preservatives and neutralizing substances as well as the detection capability of official tests. The objective of this study was to evaluate the analytical sensitivity of legislation-described tests and nonspecific microbial inhibition tests, and to investigate the effect of such substances on microbial growth inhibition and the persistence of detectable residues after 24/48h of refrigeration. Batches of raw milk, free from any contaminant, were divided into aliquots and mixed with different concentrations of formaldehyde, hydrogen peroxide, sodium hypochlorite, chlorine, chlorinated alkaline detergent, or sodium hydroxide. The analytical sensitivity of the official tests was 0.005%, 0.003%, and 0.013% for formaldehyde, hydrogen peroxide, and hypochlorite, respectively. Chlorine and chlorinated alkaline detergent were not detected by regulatory tests. In the tests for neutralizing substances, sodium hydroxide could not be detected when acidity was accurately neutralized. The yogurt culture test gave results similar to those obtained by official tests for the detection of specific substances. Concentrations of 0.05% of formaldehyde, 0.003% of hydrogen peroxide and 0.013% of sodium hypochlorite significantly reduced (P<0.05) the microbial counts in milk after 24 and 48h refrigeration. Formaldehyde and sodium hypochlorite remained detectable in milk after 48 and 24h of refrigeration, respectively; while hydrogen peroxide could not be detected after 24h. Official tests for the detection of milk fraud by the addition of preservatives and neutralizing substances present limitations and may be ineffective in detecting milk adulteration.(AU)

Fraudes no leite têm sido um problema recorrente no Brasil, tornando importante conhecer o efeito dos conservantes e neutralizantes utilizados com maior frequência, e a capacidade de detecção das provas oficiais. O objetivo deste trabalho foi avaliar a sensibilidade analítica de provas descritas pela legislação, das provas por inibição microbiana inespecífica, o efeito dessas substâncias na inibição do crescimento microbiano e a persistência de resíduos detectáveis após 48 horas de refrigeração. Lotes de leite cru, livres de sustâncias adulterantes, foram aliquotados e adicionados de diferentes concentrações de formaldeído, peróxido de hidrogênio, hipoclorito de sódio, cloro, detergente alcalino clorado e hidróxido de sódio. A sensibilidade analítica das provas oficiais foi: 0,005% para formaldeído; 0,003% para peróxido de hidrogênio e 0,013% para hipoclorito. Cloro e detergente alcalino clorado não foram detectados pelas provas oficiais. A prova de neutralizantes não detectou hidróxido de sódio quando a acidez foi neutralizada com precisão. A prova da cultura de iogurte apresentou resultados próximos ao das provas oficiais para substâncias específicas. Concentrações de 0,05% formaldeído, 0,003% de peróxido de hidrogênio e 0,013% de hipoclorito de sódio reduziram significativamente (P 0,05) a microbiota do leite após 24 e 48 horas de refrigeração. O formaldeído e hipoclorito de sódio permaneceram detectável no leite após 48 e 24 horas de refrigeração, respectivamente e o peróxido de hidrogênio não foi detectável após 24 horas. As provas oficiais para a pesquisa de fraudes por adição de conservantes e neutralizantes ao leite apresentam limitações e podem não ser capazes de detectar adulterações no leite.(AU)

Estratégias profiláticas contra estreptococose mediante diferentes metodologias de inativação, adjuvantes e suplementação com Mananoligossacarídeos em tilápias-do-nilo

O presente estudo teve como objetivo desenvolver estratégias profilácticas contra Streptococcus agalactiae mediante distintas metodologias de inativação, adjuvantes e suplementação com mananoligossacarídeos em tilápias-do-nilo. Para isto, no primeiro experimento foram comparadas três vacinas inativadas, usando três metodologias: formaldeído, peróxido de hidrogênio e manipulação de pH. Seguido, foi realizado um segundo experimento avaliando o efeito de dois adjuvantes na vacina selecionada e finalmente um terceiro experimento avaliando o efeito de mananoligossacarídeos durante o período pós- vacinação. Vinte oito dias após vacinação, os peixes foram desafiados com cepa homóloga de S. agalactiae utilizando uma dose letal (DL50%-15d). Além disso, se avaliou o efeito da vacinação nos níveis de anticorpos IgM anti-Streptococcus agalactiae, nas variáveis hematológicas e na resposta imune inata. Os resultados revelaram não diferença significativa entre as três metodologias e uma eficácia moderada. Adicionalmente, a vacina inativada com peróxido de hidrogênio e administrada principalmente com adjuvante incompleto de Freund conferiu ótima proteção contra S. agalactiae e a inclusão de MOS na dieta pós-vacinação até o desafio não interferiu na eficácia da vacina experimental com peróxido de hidrogênio.

The aim of the present study was to develop prophylactic strategies against Streptococcus agalactiae by using different inactivation methods, adjuvants and supplementation with mannan oligosaccharides (MOS) in Nile tilapias. For that, in the first trial were compared three inactivated vaccines by using three methods: formaldehyde, hydrogen peroxide and pH manipulation. The second trial compared the effect of two adjuvants on the hydrogen peroxide-inactivated vaccine and finally, the third trial investigated the effect of dietary supplementation with MOS after vaccination. Twenty-eight days after vaccination, fish were challenged with a homologous strain of S. agalactiae. In addition, were determined the anti-Streptococcus agalactiae IgM antibodies, hematological parameters and innate immune response. The results revealed no significant difference between the three methods and a moderate efficacy of the vaccines. Also, the results in this study demonstrated that hydrogen peroxide-inactivated vaccine administered with either aluminum hydroxide or FIA induce optimal levels of protection, with a superior performance for FIA vaccine and the dietary inclusion of MOS after vaccination for a period of 28 days had no influence on vaccine efficacy and confirmed the high efficacy of the novel hydrogen peroxide-inactivated vaccine.