Resumo

The control of Dermanyssus gallinaein small productions of laying hens is carried out by using chemical methods. However, its indiscriminate use has generated resistance and environmental pollution problems. This problem has encouraged the use of natural substances to control mites. Thus, the objective of this work was to evaluate the acaricidal activity of the bioactivecitral (Ci), geraniol (Ge) and thymol (Thy) on D. gallinae under in vitro conditions using six concentrations (0.05, 1, 2, 3, 4 and 5g/mL). In addition, the interactions of the mixtures of the three bioactive were evaluated through binary (1:1) and tertiary (1:1:1) combinations. The interaction between of the combination of bioactive was performed by using CompuSyn software and calculating the combination index (CI). LC50, LC90, and LC99with 95% confidence limits were estimated by Probit analysis. The bioactive Ci, Ge and Thy showacaricidal activity on the poultry red mite. The combination of Ge:Thy and Ci:Ge showed very strong synergism with CI of 0.084 and 0.052, whereas Ci:Thy showed strong synergism with CI of 0.122 at a concentration of 0.05g/mL. Thetertiary combination in 1:1:1 showed a higher toxic effect and strong synergistic effects at low concentrations with 100% mortality at 1g/mL concentration with a CI of 0.147. The combination of natural bioactive could be an additional way to control D. gallinae without putting thewelfare of the birds at risk and would be an environmentally friendly measure.(AU)

O controle de Dermanyssus gallinaeem pequenas produções de poedeiras é realizado por métodos químicos.No entanto, seu uso indiscriminado tem gerado problemas de resistência e poluição ambiental. Este problema tem incentivado o uso de substâncias naturais para o controle de ácaros. Assim, o objetivo deste trabalho foi avaliar a atividade acaricida dos bioativos citral (Ci), geraniol (Ge) e timol (Thy) sobre D. gallinaeem condições in vitro utilizando seis concentrações (0,05, 1, 2, 3, 4 e 5g/mL). Além disso, as interações das misturas dos três bioativos foram avaliadas por meio decombinações binárias (1:1) e terciárias (1:1:1). O sinergismo da combinação dos bioativos foi realizado utilizando o software CompuSyn e calculando o índice de combinação (CI). LC50, LC90e LC99com limites de confiança de 95% foram estimados por análise Probit. Os bioativos Ci, Ge e Thy apresentam atividade acaricida sobre o ácaro-vermelho-da-aves. A combinação de Ge:Thy e Ci:Ge apresentou sinergismo muito forte com CI de 0,084 e 0,052, enquanto Ci:Thy apresentou forte sinergismo com CI de 0,122 na concentração de 0,05g/mL. A combinação terciária em 1:1:1 apresentou maior efeito tóxico e fortes efeitos sinérgicos em baixas concentrações com 100% de mortalidade em concentração de 1g/mL com CI de 0,147. A combinação de bioativos naturais poderia ser uma forma adicional de controle deD. gallinaesem colocar em risco o bem-estar das aves e seria uma medida ecologicamente correta.(AU)

Resumo

Os antimicrobianos são amplamente utilizados na medicina veterinária, portanto são necessários critérios na hora da prescrição desses fármacos a fim de evitar a resistência bacteriana que se tornou uma grande preocupação tanto para a saúde humana quanto para a medicina veterinária, devido ao seu uso indiscriminado. Uma técnica muito utilizada na rotina, são as associações entre antimicrobianos, que combinam o mecanismo de ação de cada fármaco para se obter os efeitos desejados, acarretando nas interações medicamentosas. Porém, se utilizado de forma incorreta, essas interações podem ser prejudiciais para a saúde dos pacientes. O objetivo desse estudo foi analisar prontuários de pacientes caninos e felinos hospitalizados afim de avaliar os critérios de seleção para o uso de antimicrobianos e suas associações. Foram analisados 112 prontuários, sendo eles 24 felinos e 88 caninos atendidos e hospitalizados no Hospital Veterinário "Prof. Ricardo Alexandre Rippler" da Universidade Vila Velha-UVV. O estudo demonstrou que o metronidazol foi o antimicrobiano mais utilizado em cães e a amoxicilina com clavulanato de potássio foi o mais utilizado nos felinos, além disso, a amoxicilina com clavulanato de potássio e metronidazol foi a associação mais observada em cães e gatos. A maior parte dos pacientes fizeram uso dos antibióticos de forma empírica, o que pode contribuir para a resistência microbiana. Além disso, foram encontradas algumas interações entre antimicrobianos de efeitos antagônicos, porém a maioria das associações foram realizadas de forma correta provocando efeito sinérgico no organismo dos pacientes. Conclui-se que o conhecimento sobre a utilização dos antimicrobianos na rotina da internação de cães e gatos é importante e com base nesses conhecimentos podemos aplicar medidas para atenuar a resistência aos antimicrobianos.

Antimicrobials are widely used in veterinary medicine, so criteria are needed when prescribing these drugs in order to avoid bacterial resistance, which has become a major concern for both human health and veterinary medicine, due to its indiscriminate use. A technique widely used in routine is the association between antimicrobials, which combine the mechanism of action of each drug to obtain the desired effects, resulting in drug interactions. However, if used incorrectly, these interactions can be harmful to the health of patients. The aim of this study was to analyze the medical records of hospitalized canine and feline patients in order to assess the selection criteria for the use of antimicrobials and their associations. 112 medical records were analyzed, of which 24 were cats and 88 canines treated and hospitalized at the "Prof. Ricardo Alexandre Rippler" from Universidade Vila Velha-UVV. The study showed that metronidazole was the most used antimicrobial in dogs and amoxicillin with potassium clavulanate was the most used in felines. Furthermore, amoxicillin with potassium clavolanate and metronidazole was the most observed association in dogs and cats. Most patients used antibiotics empirically, which may contribute to microbial resistance. In addition, some interactions were found between antimicrobials with antagonistic effects, but most associations were correctly performed, causing a synergistic effect in the patients' bodies. It is concluded that knowledge about the use of antimicrobials in the routine hospitalization of dogs and cats is important and based on this knowledge we can apply measures to mitigate antimicrobial resistance.

Resumo

Green synthesis of silver nanoparticles (AgNPs) is an ecofriendly, cost-effective and promising approach for discovery of novel therapeutics. The aim of the current work was to biogenic synthesize, characterize AgNPs using seed extracts of three economically important varieties of date palm (Iklas, Irziz and Shishi), and assess their anti-pathogenic bacterial activities. AgNPs were synthesised then characterised using electron microscopy and Fourier transform infrared analyses. The bactericidal activities of AgNPs against five different bacterial pathogens, Bacillus subtilis, Escherichia coli, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and Streptococcus pneumoniae, were determined in vitro. In particular, changes in membrane integrity of virulent bacterial strains in response to AgNPs were investigated. Results of lactate dehydrogenase, alkaline phosphatase activity assays, and measurement of membrane potential revealed that the cytotoxic effects of the AgNPs were mainly centred on the plasma membrane of bacterial cells, leading to loss of its integrity and eventually cell death. In conclusion, green synthesis of AgNPs is an efficient, cost-effective and promising strategy to combat virulent antibiotic-resistant strains.

A síntese verde de nanopartículas de prata (AgNPs) é uma abordagem ecologicamente correta, econômica e promissora para a descoberta de novas terapêuticas. O objetivo do presente trabalho foi sintetizar biogênica, caracterizar AgNPs usando extratos de sementes de três variedades economicamente importantes de tamareira (Iklas, Irziz e Shishi) e avaliar suas atividades bacterianas antipatogênicas. AgNPs foram sintetizados e caracterizados usando microscopia eletrônica e análise de infravermelho por transformada de Fourier. As atividades bactericidas de AgNPs contra cinco diferentes patógenos bacterianos, Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Staphylococcus aureus resistente à meticilina e Streptococcus pneumoniae, foram determinadas in vitro. Em particular, foram investigadas alterações na integridade da membrana de cepas bacterianas virulentas em resposta a AgNPs. Os resultados da lactato desidrogenase, dos ensaios da atividade da fosfatase alcalina e da medição do potencial de membrana revelaram que os efeitos citotóxicos dos AgNPs estavam principalmente centrados na membrana plasmática das células bacterianas, levando à perda de sua integridade e, eventualmente, à morte celular. A síntese verde de AgNPs é uma estratégia eficiente, econômica e promissora para combater cepas virulentas resistentes a antibióticos.

Resumo

The application of herbicide tank mixtures is a common practice in agricultural settings, especially for controlling weed communities with mono and eudicotyledons species occurring simultaneously. Therefore, thisstudy was carried out with the objective of evaluating the effectiveness and interaction of dicamba-haloxyfop tank mixtures used to control four weed species. For this, four different experiments were conducted, each with one of the plant species, namely: sourgrass (Digitaria insularis), horseweed (Conyza spp.), morning glory (Ipomoea triloba) and goosegrass (Eleusine indica). In each experiment, the experimental design consisted of completely randomized blocks, in a 4x4 factorial scheme of treatments, totaling 16 treatments with five replications, i.e., 80 plots of each species. Four doses of the herbicide dicamba (480, 240, 120 and 0 g ha-1) and four doses of the herbicide haloxyfop (60, 30, 15 and 0 g ha-1) were adopted. Percentage control was evaluated at 14 and 28 days after application (DAA) and mass of dry matter was evaluated at 28 DAA. Antagonistic, additive and synergistic effects were observed for dicamba-haloxyfop tank mixtures, with a greater preponderance of additive effects. Considering all four plant species, in different doses and dates of evaluation, 72 dicamba-haloxyfop interactions were evaluated, in which 50 were considered additives.

A aplicação de misturas de herbicidas é uma prática recorrente no ambiente agrícola, sobretudo para controle de comunidades mistas de plantas daninhas, quando há ocorrência simultânea de espécies mono e eudicotiledôneas. Assim sendo, este trabalho foi realizado com o objetivo de avaliar a eficácia e a interação de misturas dos herbicidas haloxyfop (graminicida) e dicamba (latifolicida) para controle de quatro espécies de plantas daninhas.  Para tanto, quatro experimentos distintos foram realizados, cada um com uma espécie vegetal, a saber: capim-amargoso (Digitaria insularis), buva (Conyza spp.), corda-de-viola (Ipomoea triloba) e capim-pé-de-galinha (Eleusine indica). Em cada experimento, foi adotado modelo experimental de blocos ao acaso, no esquema fatorial 4x4, totalizando 16 tratamentos e cinco repetições, ou seja, 80 parcelas de cada espécie. Foram utilizadas quatro doses do herbicida dicamba (480, 240, 120 e 0 g ha-1) e quatro doses do herbicida haloxyfop (60, 30, 15 e 0 g ha-1). Foi avaliado o controle percentual das parcelas aos 14 e 28 dias após aplicação (DAA) e massa seca residual aos 28 DAA. Foram observados efeitos antagônicos, aditivos e sinérgicos para misturas entre dicamba e haloxyfop, com maior preponderância de efeitos aditivos. Considerando-se todas as quatro espécies vegetais, em diferentes doses e datas de avaliação, foram avaliadas 72 misturas

Resumo

The objective of this research was to develop fertility life tables in order to estimate the population parameters of black aphid (Aphis craccivora Koch) in cowpea (Vigna unguiculata) varieties, aiming to propose a risk scale for its use. The experiment consisted of six treatments and six replicates (five varieties plus the cultivar VITA 7 as a susceptible control). A cohort was formed with six adult females distributed in six replicates of each genotype, and the insects were observed daily. Based on the data, fertility life tables were drawn for each variety and the population parameters were estimated. The different values of the finite growth rate (λ) were considered to propose a risk scale for the use of the genotypes. The results obtained give the dimension of the variability of V. unguiculata in respect to the character, resistance to A. craccivora, with antibiosis as the main mechanism of resistance. Considering all the results, the varieties studied can be classified according to their suitability as a plant favorable to the development of the black aphid as follows: VITA 7 > CE-13 > CE-51 > CE-08 = CE-07. The proposal of a risk scale for the use of V. unguiculata genotypes against the A. craccivora population, based on the finite growth rate (λ) values, was adequate to discriminate the varieties studied.(AU)

Objetivou-se nesta pesquisa elaborar tabelas de vida de fertilidade com o intuito de estimar os parâmetros populacionais de pulgão-preto (Aphis craccivora Koch) em variedades de feijão-caupi (Vigna unguiculata), visando propor uma escala de risco para o seu uso. O experimento constituiu-se em seis tratamentos (cinco variedades mais o cultivar VITA 7 como padrão de suscetibilidade) com seis repetições. Formou-se uma coorte com seis fêmeas adultas distribuídas em cada genótipo, sendo todos os indivíduos observados diariamente. De posse dos dados, foram elaboradas tabelas de vida de fertilidade para cada variedade e estimados os parâmetros populacionais. Para propor uma escala de risco de uso de genótipos, ponderou-se sob os diferentes valores da razão finita de crescimento (λ). Os resultados obtidos dão a dimensão da variabilidade de V. unguiculata com relação ao caráter da resistência a A. craccivora, sendo a antibiose o principal mecanismo de resistência associado. Considerando-se todos os resultados, foi possível hierarquizar as variedades estudadas segundo sua aptidão como planta favorável ao desenvolvimento ao pulgão-preto conforme segue: VITA 7 >> CE-13 > CE-51 > CE-08 = CE-07. A proposta de uma escala de risco do uso de genótipos de V. unguiculata frente à população de A. craccivora, baseada nos valores da razão finita de crescimento (λ), foi adequada para discriminar as variedades estudadas.(AU)

Resumo

Minas artisanal cheese is made from endogenous starter cultures, including lactic acid bacteria (LAB). Some LAB may possess probiotic potential. Thus, this study aimed to evaluate the in vitro probiotic properties of lactobacilli isolated from Minas artisanal cheeses produced in Minas Gerais. Ten samples of lactobacilli, formerly isolated from those cheeses, were submitted to the following assays: antimicrobial susceptibility, tolerance to artificial gastric juice and biliary salts, production of hydrogen peroxide and antagonism against pathogenic and non-pathogenic micro-organisms. Only L. plantarum (C0) was sensitive to all tested antimicrobials, while the other LAB samples were resistant to at least one drug. Six samples were tolerant to artificial gastric juice, and L. brevis (A6) even grew in that medium. Three samples were tolerant to biliary salts. Only L. brevis (E35) produced hydrogen peroxide. Difference (P< 0.05) was observed among the means of inhibition haloes of lactobacilli against Enterococcus faecalis ATCC 19433 and Lactobacillus plantarum C24 in spot-on-the-lawn assay. All samples of lactobacilli inhibited Escherichia coli ATCC 25922, Salmonella enterica var. Typhimurium ATCC 14028 in co-culture antagonism test (P< 0.0001). Most lactobacilli samples showed in vitro probiotic potential. From the tested samples, L. brevis (A6) presented the best results considering all in vitro probiotic tests.(AU)

O queijo minas artesanal é produzido por culturas starters endógenas, incluindo bactérias ácido-láticas (BAL). Algumas BAL podem possuir potencial probiótico. Com isso, este estudo teve como objetivo avaliar as propriedades probióticas in vitro de lactobacilos isolados de queijo minas artesanal produzido no estado de Minas Gerais. Dez amostras de lactobacilos, previamente isoladas desses queijos, foram submetidas aos seguintes testes: susceptibilidade aos antimicrobianos, tolerância ao suco gástrico artificial e aos sais biliares, produção de peróxido de hidrogênio e antagonismo contra micro-organismos patogênicos e não patogênicos. Apenas L. plantarum (C0) foi sensível a todos os antimicrobianos testados, enquanto as outras amostras de BAL foram resistentes a, pelo menos, uma droga testada. Seis amostras foram tolerantes ao suco gástrico artificial, e L. brevis (A6) apresentou crescimento nesse meio. Três amostras foram tolerantes aos sais biliares. Apenas L. brevis (E35) produziu peróxido de hidrogênio. Diferença (P<0,05) foi observada entre as médias dos halos de inibição de lactobacilos contra Enterococcus faecalis ATCC 19433 e Lactobacillus plantarum C24 no teste do spot-on-the-lawn. Todas as amostras de lactobacilos inibiram Escherichia coli ATCC 25922, Salmonella enterica var. Typhimurium ATCC 14028 no teste de antagonismo em cocultura (P<0,0001). A maioria das amostras de lactobacilos apresentou potencial probiótico in vitro. Com base nas amostras testadas, L. brevis (A6) apresentou os melhores resultados, considerando-se todos os testes probióticos in vitro.(AU)

Resumo

In Brazil, there are few records of insects associated with the cultivation of lima beans; among them, there is the black aphid Aphis craccivora Koch, 1854. The objective of this study was to evaluate the effects of silicon application on the resistance induction of lima bean plants, Phaseolus lunatus, to the black aphid A. craccivora. The experiment was conducted in the Entomology Laboratory of the Phytosanitary Sector of Centro de Ciências Agrárias, Universidade Federal do Piauí (UFPI), Brazil. The effects of the following treatments on biological aspects of the insect were evaluated: silicon applied to soil; silicon applied to soil + leaf; silicon applied to leaf; and control, without silicon application. The following biological variables were evaluated: generation period, reproductive period, and the fertility and daily average of produced nymphs per female. Plant silicon and lignin content were also evaluated. A 1% solution of silicic acid (2.0 g of product diluted in 200 mL of water) was applied around the plant stem (on soil), 15 days after emergence. Leaf application was performed with a 1-L spray, 5 days after the soil application. The non-preference of A. craccivora on lima beans was also evaluated. The evaluations were performed after 48 and 72 hours of infestation by counting nymphs and adults at each leaf section. Silicon application reduces nymph production, thereby interfering in the biological aspects of A. craccivora. Therefore, it can be used in cowpea pest management programs.(AU)

São poucos os registros no Brasil de insetos associados à cultura da fava; entre eles, destaca-se o pulgão preto Aphis craccivora Koch, 1854. O objetivo deste estudo foi avaliar os efeitos da aplicação de silício na indução de resistência de plantas de feijão-fava Phaseolus lunatus a esse inseto. O experimento foi conduzido no Laboratório de Entomologia do setor de Fitossanidade do Centro de Ciências Agrárias da Universidade Federal do Piauí (UFPI). Os efeitos da aplicação do silício sobre os aspectos biológicos do inseto foram avaliados utilizando os tratamentos: silício aplicado no solo, silício aplicado no solo + folha, silício aplicado à folha; e controle, sem aplicação de silício. Foram avaliadas as variáveis biológicas: duração do período pré-reprodutivo, período reprodutivo e fertilidade, e média diárias de ninfas produzidas por fêmea. Os teores de silício e de lignina nas plantas também foram avaliados. O ácido silícico foi aplicado em uma solução a 1% ao redor do caule das plantas (no solo), 15 dias após a emergência, diluindo-se 2,0 g do produto em 200 mL de água. Já a aplicação foliar foi realizada com um pulverizador de 1 L, 5 dias após a aplicação em solo. A não preferência de A. craccivora em feijão também foi avaliada. As avaliações foram realizadas após 48 e 72 horas da infestação, por meio da contagem de ninfas e adultos em cada secção foliar. A aplicação de silício promove a redução da produção de ninfas, interferindo nos aspectos biológicos de A. craccivora, podendo ser utilizado em programas de manejo de pragas do feijão-fava.(AU)

Resumo

This study was aimed at assessing some biological parameters of Bemisia tabaci B biotype at immature stages to examine antibiosis in six soybean genotypes, besides antixenosis resistance to oviposition in choice and non-choice tests, under greenhouse and laboratory conditions. Between April 2016 and August 2016, bioassays were carried out at the Laboratory of Applied Entomology at College of Agricultural Sciences at Federal University of Grande Dourados (UFGD) Dourados (MS), Brazil. The following variables were evaluated: egg incubation period, nymphal and egg-to-adult duration, egg and nymph viability, and egg-to-adult survival on the soybean genotypes 68i70 RSF IPRO, M6210 IPRO, MS 947 IPRO, BMX Potência RR, M6410 IPRO, and ANTA 82 RR. Antixenosis resistance to oviposition by the silverleaf whitefly was found for MS 947 IPRO, while oviposition was highest for ANTA 82 RR, M6210 IPRO, and M6410 IPRO. The genotype MS 947 IPRO adversely affected egg and nymph viability, and egg-to-adult survival rates was the lowest among genotypes (59.75%), suggesting antibiosis resistance to this pest.(AU)

Este trabalho teve por objetivo avaliar a antibiose em seis genótipos de soja da Bemisia tabaci biótipo B mediante alguns parâmetros biológicos das fases imaturas do inseto, assim como analisar a resistência do tipo antixenose para oviposição em testes com e sem chance de escolha, em laboratório e casa de vegetação. Os ensaios foram conduzidos no Laboratório de Entomologia Aplicada da Faculdade de Ciências Agrárias da Universidade Federal da Grande Dourados (UFGD), Dourados (MS), entre os meses de abril e agosto de 2016. As variáveis averiguadas foram: período de incubação dos ovos; período ninfal; duração de ovo a adulto; viabilidade de ovo; viabilidade de ninfa e sobrevivência de ovo a adulto. Os genótipos de soja avaliados foram: 68i70 RSF IPRO, M6210 IPRO, MS 947 IPRO, BMX Potência RR, M6410 IPRO e ANTA 82 RR. O genótipo que apresentou antixenose para oviposição da mosca-branca foi o MS 947 IPRO, e constatou-se que o maior número de postura foi realizado nos genótipos ANTA 82 RR, M6210 IPRO e M6410 IPRO. O genótipo MS 947 IPRO também afetou negativamente a viabilidade de ovos e ninfas, bem como a sobrevivência de ovo a adulto, com as menores porcentagens de sobrevivência (59,75%), indicando possível resistência do tipo antibiose à mosca-branca.(AU)

Resumo

ABSTRACT Salinity and alkalinity are major abiotic stresses that limit growth and development of poplar. We investigated biocontrol potential of saline- and alkaline-tolerant mutants of Trichoderma asperellum to mediate the effects of salinity or alkalinity stresses on Populus davidiana × P. alba var. pyramidalis (PdPap poplar) seedlings. A T-DNA insertion mutant library of T. asperellum was constructed using an Agrobacterium tumefaciens mediated transformation system; this process yielded sixty five positive transformants (T1-T65). The salinity tolerant mutant, T59, grew in Potato Dextrose Agar (PDA) containing up to 10% (1709.40 mM) NaCl. Under NaCl-rich conditions, T59 was most effective in inhibiting Alternaria alternata (52.00%). The alkalinity tolerant mutants, T3 and T5, grew in PDA containing up to 0.4% (47.62 mM) NaHCO3. The ability of the T3 and T5 mutants to inhibit Fusarium oxysporum declined as NaHCO3 concentrations increased. NaHCO3 tolerance of the PdPap seedlings improved following treatment with the spores of the WT, T3, and T5 strains. The salinity tolerant mutant (T59) and two alkalinity tolerant mutants (T3 and T5) generated in this study can be applied to decrease the incidence of pathogenic fungi infection under saline or alkaline stress.

Resumo

ABSTRACT This work aimed to characterize 20 isolates obtained from upland rice plants, based on phenotypic (morphology, enzymatic activity, inorganic phosphate solubilization, carbon source use, antagonism), genotypic assays (16S rRNA sequencing) and plant growth promotion. Results showed a great morphological, metabolic and genetic variability among bacterial isolates. All isolates showed positive activity for catalase and protease enzymes and, 90% of the isolates showed positive activity for amylase, catalase and, nitrogenase. All isolates were able to metabolize sucrose and malic acid in contrast with mannitol, which was metabolized only by one isolate. For the other carbon sources, we observed a great variability in its use by the isolates. Most isolates showed antibiosis against Rhizoctonia solani (75%) and Sclerotinia sclerotiorum (55%) and, 50% of them showed antibiosis against both pathogens. Six isolates showed simultaneous ability of antibiosis, inorganic phosphate solubilization and protease activity. Based on phylogenetic analysis of the 16S rRNA gene all the isolates belong to Bacillus genus. Under greenhouse conditions, two isolates (S4 and S22) improved to about 24%, 25%, 30% and 31% the Total N, leaf area, shoot dry weight and root dry weight, respectively, of rice plants, indicating that they should be tested for this ability under field conditions.

Resumo

Abstract In this study for the first-time microbial communities in the caves located in the mountain range of Hindu Kush were evaluated. The samples were analyzed using culture-independent (16S rRNA gene amplicon sequencing) and culture-dependent methods. The amplicon sequencing results revealed a broad taxonomic diversity, including 21 phyla and 20 candidate phyla. Proteobacteria were dominant in both caves, followed by Bacteroidetes, Actinobacteria, Firmicutes, Verrucomicrobia, Planctomycetes, and the archaeal phylum Euryarchaeota. Representative operational taxonomic units from Koat Maqbari Ghaar and Smasse-Rawo Ghaar were grouped into 235 and 445 different genera, respectively. Comparative analysis of the cultured bacterial isolates revealed distinct bacterial taxonomic profiles in the studied caves dominated by Proteobacteria in Koat Maqbari Ghaar and Firmicutes in Smasse-Rawo Ghaar. Majority of those isolates were associated with the genera Pseudomonas and Bacillus. Thirty strains among the identified isolates from both caves showed antimicrobial activity. Overall, the present study gave insight into the great bacterial taxonomic diversity and antimicrobial potential of the isolates from the previously uncharacterized caves located in the world's highest mountains range in the Indian sub-continent.

Resumo

Abstract A total of 276 endophytic bacteria were isolated from the root nodules of soybean (Glycine max L.) grown in 14 sites in Henan Province, China. The inhibitory activity of these bacteria against pathogenic fungus Phytophthora sojae 01 was screened in vitro. Six strains with more than 63% inhibitory activities were further characterized through optical epifluorescence microscopic observation, sequencing, and phylogenetic analysis of 16S rRNA gene, potential plant growth-promoting properties analysis, and plant inoculation assay. On the basis of the phylogeny of 16S rRNA genes, the six endophytic antagonists were identified as belonging to five genera: Enterobacter, Acinetobacter, Pseudomonas, Ochrobactrum, and Bacillus. The strain Acinetobacter calcoaceticus DD161 had the strongest inhibitory activity (71.14%) against the P. sojae 01, which caused morphological abnormal changes of fungal mycelia; such changes include fracture, lysis, formation of a protoplast ball at the end of hyphae, and split ends. Except for Ochrobactrum haematophilum DD234, other antagonistic strains showed the capacity to produce siderophore, indole acetic acid, and nitrogen fixation activity. Regression analysis suggested a significant positive correlation between siderophore production and inhibition ratio against P. sojae 01. This study demonstrated that nodule endophytic bacteria are important resources for searching for inhibitors specific to the fungi and for promoting effects for soybean seedlings.

Resumo

Tomato bacterial spot caused by Xanthomonas spp., is a common disease in tomato fields that causes significant economic losses. Due to the difficulty with control of bacterial spot by conventional methods, new techniques such as biological control and induction of resistance are gaining prominence. This study aimed to select saprobe fungi from semi-arid regions of the Brazilian Northeast for the biological control of bacterial spot of tomato. To select the best isolates to control bacterial spot, a greenhouse experiment was initially conducted. Tomato plants (‘Santa Cruz Kada’) were treated with filtrates of 25 saprobe fungi and inoculated three days later with Xanthomonas euvesicatoria. Filtrates of Memnoniella levispora, Periconia hispidula, Zygosporium echinosporum, and Chloridium virescens var. virescens were selected as the most effective. Filtrates and volatile compounds from these four isolates were tested for their antibacterial activity in cultures of X. euvesicatoria and in tomato plants (‘Santa Cruz Kada’) inoculated with X. euvesicatoria. In vitro, the addition of nonvolatile fungal metabolites into the culture medium at 5% and 50% (v/v) inhibited bacterial growth by 28.9% and 53.8%, respectively. The volatile compounds produced by C. virescens var. virescens reduced the number of colony-forming units of X. euvesicatoria by 25.9%. In vivo, all treatments reduced from 62.4 to 71.3% the area under bacterial spot progress curve, showing the same control efficacy as the commercial resistance inducer used as a positive control (acibenzolar-S-methyl). Systemicity of the fungal filtrates was confirmed in a separate experiment, where application of the treatments exclusively to the third leaf decreased the severity of the disease on the fourth leaf (except for C. virescens var. virescens)...

A mancha bacteriana do tomateiro causada por Xanthomonas spp. é uma doença frequente nos campos de cultivo, provocando importantes perdas econômicas. Devido à dificuldade de controle com os métodos tradicionais, novas ferramentas de manejo para esta doença, como o controle biológico e a indução de resistência vêm ganhando destaque. O objetivo desse trabalho foi a seleção de fungos sapróbios do semiárido nordestino brasileiro para o controle biológico da mancha bacteriana do tomateiro. Inicialmente, com o objetivo de selecionar os isolados que apresentassem melhor controle da mancha bacteriana, foi montado um ensaio em casa de vegetação com tomateiros (‘Santa Cruz Kada’) tratados com os filtrados de 25 fungos sapróbios e inoculados com a bactéria Xanthomonas euvesicatoria três dias depois. Foram selecionados os isolados de Memnoniella levispora, Periconia hispidula, Zygosporium echinosporum e Chloridium virescens var. virescens. Filtrados e voláteis fúngicos desses quatro isolados foram testados in vitro, para se determinar a sensibilidade da bactéria fitopatogênica, e in vivo em tomateiros (‘Santa Cruz Kada’) tratados e inoculados com X. euvesicatoria. A incorporação de metabólitos não voláteis dos fungos no meio de cultura a 5% e 50% (v/v) controlou o crescimento da bactéria em até 28,9% e 53,8%, respectivamente. Os compostos voláteis produzidos por C. virescens var. virescens inibiram até 25,9% das unidades formadoras de colônias. Com relação ao experimento in vivo, todos os tratamentos testados reduziram de 62,4 a 71,3% a área abaixo da curva de progresso da mancha bacteriana, mostrando nível de controle igual ao indutor de resistência comercial utilizado como controle positivo (acibenzolar-S-metílico). A sistemicidade deste controle foi confirmada em outro experimento, onde a aplicação dos tratamentos somente na terceira folha determinou menor severidade da doença na quarta folha (exceto para C. virescens var. virescens)...

Resumo

Abstract This study aimed to evaluate the biocontrol potential of bacteria isolated from different plant species and soils. The production of compounds related to phytopathogen biocontrol and/or promotion of plant growth in bacterial isolates was evaluated by measuring the production of antimicrobial compounds (ammonia and antibiosis) and hydrolytic enzymes (amylases, lipases, proteases, and chitinases) and phosphate solubilization. Of the 1219 bacterial isolates, 92% produced one or more of the eight compounds evaluated, but only 1% of the isolates produced all the compounds. Proteolytic activity was most frequently observed among the bacterial isolates. Among the compounds which often determine the success of biocontrol, 43% produced compounds which inhibit mycelial growth of Monilinia fructicola, but only 11% hydrolyzed chitin. Bacteria from different plant species (rhizosphere or phylloplane) exhibited differences in the ability to produce the compounds evaluated. Most bacterial isolates with biocontrol potential were isolated from rhizospheric soil. The most efficient bacteria (producing at least five compounds related to phytopathogen biocontrol and/or plant growth), 86 in total, were evaluated for their biocontrol potential by observing their ability to kill juvenile Mesocriconema xenoplax. Thus, we clearly observed that bacteria that produced more compounds related to phytopathogen biocontrol and/or plant growth had a higher efficacy for nematode biocontrol, which validated the selection strategy used.

Resumo

Abstract Actinobacteria occur in many environments and have the capacity to produce secondary metabolites with antibiotic potential. Identification and taxonomy of actinobacteria that produce antimicrobial substances is essential for the screening of new compounds, and sequencing of the 16S region of ribosomal DNA (rDNA), which is conserved and present in all bacteria, is an important method of identification. Melanized fungi are free-living organisms, which can also be pathogens of clinical importance. This work aimed to evaluate growth inhibition of melanized fungi by actinobacteria and to identify the latter to the species level. In this study, antimicrobial activity of 13 actinobacterial isolates from the genus Streptomyces was evaluated against seven melanized fungi of the genera Exophiala, Cladosporium, and Rhinocladiella. In all tests, all actinobacterial isolates showed inhibitory activity against all isolates of melanized fungi, and only one actinobacterial isolate had less efficient inhibitory activity. The 16S rDNA region of five previously unidentified actinobacterial isolates from Ilha do Mel, Paraná, Brazil, was sequenced; four of the isolates were identified as Streptomyces globisporus subsp. globisporus, and one isolate was identified as Streptomyces aureus. This work highlights the potential of actinobacteria with antifungal activity and their role in the pursuit of novel antimicrobial substances.

Resumo

ABSTRACT Tomato is one of the most important vegetables in the world. Decay after harvest is a major issue in the development of tomato industry. Currently, the most effective method for controlling decay after harvest is storage of tomato at low temperature combined with usage of chemical bactericide; however, long-term usage of chemical bactericide not only causes pathogen resistance but also is harmful for human health and environment. Biocontrol method for the management of disease after tomato harvest has great practical significance. In this study, antagonistic bacterium B-6-1 strain was isolated from the surface of tomato and identified as Enterobacter cowanii based on morphological characteristics and physiological and biochemical features combined with sequence analysis of 16SrDNA and ropB gene and construction of dendrogram. Effects of different concentrations of antagonistic bacterium E. cowanii suspension on antifungal activity after tomato harvest were analyzed by mycelium growth rate method. Results revealed that antifungal activity was also enhanced with increasing concentrations of antagonistic bacterium; inhibitory rates of 1 × 105 colony-forming units (cfu)/mL antagonistic bacterial solution on Fusarium verticillioides, Alternaria tenuissima, and Botrytis cinerea were 46.31%, 67.48%, and 75.67%, respectively. By using in vivo inoculation method, it was further confirmed that antagonistic bacterium could effectively inhibit the occurrence of B. cinerae after tomato harvest, biocontrol effect of 1 × 109 cfu/mL zymotic fluid reached up to 95.24%, and antagonistic bacterium E. cowanii has biocontrol potential against B. cinerea after harvest of fruits and vegetables.

Resumo

Abstract Aneurinibacillus aneurinilyticus strain CKMV1 was isolated from rhizosphere of Valeriana jatamansi and possessed multiple plant growth promoting traits like production of phosphate solubilization (260 mg/L), nitrogen fixation (202.91 nmol ethylene mL-1 h-1), indole-3-acetic acid (IAA) (8.1 µg/mL), siderophores (61.60%), HCN (hydrogen cyanide) production and antifungal activity. We investigated the ability of isolate CKMV1 to solubilize insoluble P via mechanism of organic acid production. High-performance liquid chromatography (HPLC) study showed that isolate CKMV1 produced mainly gluconic (1.34%) and oxalic acids. However, genetic evidences for nitrogen fixation and phosphate solubilization by organic acid production have been reported first time for A. aneurinilyticus strain CKMV1. A unique combination of glucose dehydrogenase (gdh) gene and pyrroloquinoline quinone synthase (pqq) gene, a cofactor of gdh involved in phosphate solubilization has been elucidated. Nitrogenase (nif H) gene for nitrogen fixation was reported from A. aneurinilyticus. It was notable that isolate CKMV1 exhibited highest antifungal against Sclerotium rolfsii (93.58%) followed by Fusarium oxysporum (64.3%), Dematophora necatrix (52.71%), Rhizoctonia solani (91.58%), Alternaria sp. (71.08%) and Phytophthora sp. (71.37%). Remarkable increase was observed in seed germination (27.07%), shoot length (42.33%), root length (52.6%), shoot dry weight (62.01%) and root dry weight (45.7%) along with NPK (0.74, 0.36, 1.82%) content of tomato under net house condition. Isolate CKMV1 possessed traits related to plant growth promotion, therefore, could be a potential candidate for the development of biofertiliser or biocontrol agent and this is the first study to include the Aneurinibacillus as PGPR.

Resumo

Colibacilosis is one of the major diseases of calves, causing huge losses. The aim in this study was to characterize and select lactic bacteria with probiotic potential from Nellore calves raised in northern Minas Gerais. Stool samples from six healthy calves were collected, with three days old and again at three months of age. After isolation, bacteria were enumerated and submitted to morphological and biochemical characterization with API 50 CH test, pH and acid resistance to bile salts and antagonist activity in vitro for three strains of Escherichia coli. The population of lactic acid bacteria was greater (p < 0.05) in feces of the calves at colostrum phase. For resistance to chloric acid, 92.3% of isolates from newborn calves resisted pH 4.0, presenting higher resistance than the isolates from calves at three months of age. In the antagonism test, the isolates Be4 1m, Be1 2b and Be6 2a were presumptively identified as Lactobacillus salivarius, L. crispatus and L. pentosus, respectively, and produced average inhibition zones greater than 10 mm of diameter and showed resistance acid pH and bile salts, indicating potential probiotics.

A colibacilose é uma das principais doenças que acomete bezerros nas fases iniciais, provocando prejuízos à bovinocultura. Nesta pesquisa, caracterizou-se e selecionou-se cepas de bactérias láticas com potencial probiótico, provenientes de bezerros Nelore criados no norte de Minas Gerais. Foram coletadas amostras fecais de bezerros hígidos contemporâneos, com três dias de vida e novamente aos três meses de idade. Após isolamento, realizou-se a quantificação, caracterização morfológica e bioquímica com teste API 50 CH, resistência a pH ácido e a sais biliares e atividade antagonista in vitro para três cepas de Escherichia coli. Verificou-se população superior (p < 0,05) de bactérias láticas nas fezes dos bezerros na fase colostral. Quanto à resistência ao ácido clorídrico, 92,3% dos isolados de bezerros recém-nascidos resistiram ao pH 4,0, apresentando-se superior aos isolados de bezerros aos três meses de idade. No teste de antagonismo, os isolados, Be4 1m, Be1 2b e Be6 2a, identificados presuntivamente, como Lactobacillus salivarius, L. crispatus e L. pentosus, respectivamente, produziram média de halo de inibição superior a 10 mm de diâmetro e demonstraram resistência ao pH ácido e sais biliares, indicando potencial para serem utilizados como probióticos.

Resumo

Foram conduzidos dois experimentos, com o objetivo de estimar a exigência de valina e isoleucina digestível para codornas de corte em crescimento. No experimento 1, foram utilizadas 2.160 codornas de corte de um dia de idade, não sexadas, distribuídas em um delineamento inteiramente ao acaso, com arranjo fatorial 4x4, sendo quatro níveis de valina digestível (0,90, 1,10, 1,30 e 1,50%) e quatro níveis de isoleucina digestível (0,80, 1,00, 1,20 e 1,40%), totalizando 16 tratamentos, com três repetições e 45 codornas por unidade experimental. O peso corporal, o ganho de peso e a biomassa corporal acumulada aumentaram linearmente em função dos níveis de valina digestível e foram influenciados de forma quadrática, estimando 1,38% de isoleucina digestível. No experimento 2, foram utilizadas 1.440 codornas de corte não sexadas, distribuídas em um delineamento inteiramente ao acaso, com arranjo fatorial 4x4, sendo quatro níveis de valina digestível (0,82, 1,02, 1,22 e 1,42%) e quatro níveis de isoleucina digestível (0,73, 0,93, 1,13 e 1,33%), totalizando 16 tratamentos, com três repetições e 30 codornas por unidade experimental. O desempenho de codornas de corte, no período de 15 a 35 dias de idade, não foi influenciado pelo aumento dos níveis de valina e isoleucina digestível nas rações experimentais. Conclui-se que as exigências de valina e isoleucina digestível para o máximo desempenho de codornas de corte, no período de um a 14 dias de idade, foram de 1,50% e 1,38%, respectivamente, correspondendo às relações valina:lisina de 95% e isoleucina:lisina de 88%. Os menores níveis avaliados, no período de 15 a 35 dias de idade, de 0,82% de valina digestível e de 0,73% de isoleucina digestível, correspondendo às relações valina:lisina de 52% e isoleucina: lisina de 46%, foram suficientes para satisfazer as exigências nutricionais das codornas de corte sem comprometer o desempenho.(AU)

Two experiments were carried out in order to estimate the requirements of digestible valine and isoleucine for growing meat quails. In experiment 1, 2160 meat quails with 1 day of age, not sexed, were used, distributed in a completely randomized design with a 4x4 factorial arrangement, with four levels of digestible valine (0.90, 1.10, 1.30, and 1.50%) and four levels of digestible isoleucine (0.80, 1.00, 1.20, and 1.40 %), totaling 16 treatments with three replications and 45 quails per experimental unit. The body weight, the weight gain, and the accumulated body biomass linearly increased in function of digestible valine levels and were influenced in a quadratic way estimating 1.38% of digestible isoleucine. In experiment 2, 1440 meat quails, not sexed, were used, distributed in a completely randomized design with a 4x4 factorial arrangement, with four levels of digestible valine (0.82, 1.02, 1.22, and 1.42%) and four levels of digestible isoleucine (0.73, 0.93, 1.13, and 1.33%), totaling 16 treatments with three replications and 30 quails per experimental unit. The performance of meat quails from 15 to 35 days of age was not affected by increased levels of digestible valine and digestible isoleucine in the experimental diets. It was concluded that the requirements of digestible valine and digestible isoleucine for maximum performance of meat quail from one to 14 days of age were 1.50% and 1.38%, respectively, corresponding to relations: valine: lysine of 95% and isoleucine: lysine of 88%. The lower levels evaluated, in the period of 15 to 35 days old, 0.82% digestible valine and 0.73% of digestible isoleucine, corresponding to relations valine: lysine of 52% and isoleucine: lysine of 46% were sufficient to meet the nutritional requirements of meat quails without compromising performance.(AU)

Resumo

A raça Guzerá apresenta grande contribuição para pecuária brasileira devido a sua rusticidade e sobrevivência nos trópicos, além de apresentar características relacionadas desempenho, eficiência alimentar e fertilidade. Essas características são critérios importantes na determinação dos índices zootécnicos e bioeconômicos dentro no sistema de produção. No entanto, é imprescindível o entendimento sobre comportamento dessas duas características, sobretudo o consumo alimentar residual, que surge como novo parâmetro para identificação de animais superiores na utilização dos alimentos. Ainda são escassos os trabalhos na literatura na raça Guzerá quanto ao impacto da seleção para consumo alimentar residual sobre o desempenho das características de importância econômica. Dessa forma, o objetivo desse trabalho foi avaliar e estimar os parâmetros genéticos para peso aos 120 dias de idade (P120), peso aos 210 dias de idade (P210), peso aos 365 dias de idade (P365), peso aos 450 dias de idade (P450), perímetro escrotal aos 365 dias de idade (PE365), perímetro escrotal aos 450 dias de idade (PE450), área de olho de lombo (AOL), espessura de gordura subcutânea (EG), espessura de gordura subcutânea na garupa (EGP8), consumo alimentar residual (CAR) e consumo de matéria seca (CMS) em bovinos da raça Guzerá. A estimação dos parâmetros genéticos foi realizada pelo método da máxima verossimilhança restrita (REML), sob modelo animal em análises uni, bi e multicaracterística, a fim de determinar qual modelo apresenta de forma acurada as associações genéticas e fenotípicas entre essas características e assim determinar o planejamento genético e os índices de seleção sem causar antagonismos em ambas as características. As herdabilidades para P120, P210, P365, P365 foram elevadas e superiores em na análise multicaráter, ao passo que que para PE365, PE450, AOL, EG e EGP8 foram moderadas. Da mesma forma que CAR e CMS em modelo multi (0.17 e 0.22), bi (0.14 e 0.20) e uni (0.15 e 0.20). As correlações genéticas entre CAR e PE365 e PE450 foram próximas de zero nos dois modelos (0.05 e 0.04) e (-0.06 e -0.06), respectivamente. Para CMS e PE365 e PE450 foram positivas e fortemente associadas, nos dois modelos bi (0.73 e 0.61) e multi (0.64 e 0.64), o mesmo comportamento foi observado na correlação genética magnitude moderada entre CAR e CMS nas duas analises (0.46 e 0.48). O CAR correlacionou-se positivamente com EG (0.16) e com AOL (-0.07) e EGP8 (0.10), as correlações genéticas foram baixas. De modo geral as herdabilidades e correlações genéticas foram relativamente elevadas no modelo multicaracterístico, o que demonstra ser mais apropriado em virtude da melhor acurácia das estimativas dos componentes de variância e assim melhor predição dos parâmetros genéticos em relação aos demais modelos. Ganhos genéticos significativos podem ser obtidos através seleção para características de eficiência alimentar e reprodução na raça Guzerá, podendo ser inclusas simultaneamente em programas de seleção, sem acarretar em prejuízos genéticos ou econômicos e assim promover maior progresso genético dos rebanhos.

The Guzerat breed makes a great contribution to Brazilian livestock due to its rusticity and areas in the tropics, in addition to presenting characteristics related to feed efficiency and fertility. Feeding efficiency and fertility are two important criteria in determining zootechnical and bioeconomic indexes within the production system. However, an understanding of the two characteristics is essential, especially residual food consumption, which appears as a new parameter for identifying superior animals in the use of food. There is still little work in the literature on the Guzerat breed regarding the impact of selection for residual food consumption on reproductive performance in the breed. Thus, the objective of this work was to evaluate and estimate the genetic parameters for circumference scrotal at 365 days of age (SC365), circumference scrotal at 450 days of age (SC450), residual feed intake (CAR) and dry matter intake (DMI) in Guzerat cattle. The estimation of genetic parameters was performed by the method of maximum restricted likelihood (REML), under animal model in single-trait, bi-trait, and multi-trait analyzes, in order to determine which model accurately presents as genetic and phenotypic associations between traits and thus determine genetic planning and the selection indexes without causing antagonisms in both characteristics. The heritability for PE365 and PE450 in mult-trait analysis (0.43 and 34) were superior to those obtained in single-trait (0.25 and 0.28) and bi-trait analysis (0.27 and 0.29). Like CAR and DMI in multi model (0.17 and 0.22), bi-trait (0.14 and 0.20) and single-trait (0.15 and 0.20). The genetic correlations between CAR and SC365 and SC450 were close to zero in the two models (0.05 and 0.04) and (-0.06 and -0.06), respectively. For DMI and SC365 and SC450 they were positive and strongly associated, in the two bi (0.73 and 0.61) and multi (0.64 and 0.64) models, the same behavior was observed in the high magnitude genetic correlation between CAR and DMI in the two analyzes (0.46 and 0.48). In general, heritability and genetic correlations were relatively high in the mult-trait model, which proves to be more appropriate due to the better accuracy of the estimates of the variance components and thus better prediction of the genetic parameters in relation to the other models. Significant genetic gains can be obtained through selection for characteristics of feeding efficiency and reproduction in the Guzerat breed, being able to be included simultaneously in selection programs, without causing genetic or economic losses and thus promoting greater genetic progress of the herds.