RESUMO
Bacteriophages put intense selective pressure on microbes, which must evolve diverse resistance mechanisms to survive continuous phage attacks. We used a library of spontaneous Bacteriophage Insensitive Mutants (BIMs) to learn how the plant pathogen Ralstonia solanacearum resists the virulent lytic podophage phiAP1. Phenotypic and genetic characterization of many BIMs suggested that the R. solanacearum Type II Secretion System (T2SS) plays a key role in phiAP1 infection. Using precision engineered mutations that permit T2SS assembly but either inactivate the T2SS GspE ATPase or sterically block the secretion portal, we demonstrated that phiAP1 needs a functional T2SS to infect R. solanacearum. This distinction between the static presence of T2SS components, which is necessary but not sufficient for phage sensitivity, and the energized and functional T2SS, which is sufficient, implies that binding interactions alone cannot explain the role of the T2SS in phiAP1 infection. Rather, our results imply that some aspect of the resetting of the T2SS, such as disassembly of the pseudopilus, is required. Because R. solanacearum secretes multiple virulence factors via the T2SS, acquiring resistance to phiAP1 also dramatically reduced R. solanacearum virulence on tomato plants. This acute fitness trade-off suggests this group of phages may be a sustainable control strategy for an important crop disease. IMPORTANCE Ralstonia solanacearum is a destructive plant pathogen that causes lethal bacterial wilt disease in hundreds of diverse plant hosts, including many economically important crops. Phages that kill R. solanacearum could offer effective and environmentally friendly wilt disease control, but only if the bacterium cannot easily evolve resistance. Encouragingly, most R. solanacearum mutants resistant to the virulent lytic phage phiAP1 no longer secreted multiple virulence factors and had much reduced fitness and virulence on tomato plants. Further analysis revealed that phage phiAP1 needs a functional type II secretion system to infect R. solanacearum, suggesting this podophage uses a novel infection mechanism.
Assuntos
Bacteriófagos , Ralstonia solanacearum , Solanum lycopersicum , Sistemas de Secreção Tipo II , Fatores de Virulência/genética , Ralstonia solanacearum/genética , Bacteriófagos/genética , Sistemas de Secreção Tipo II/metabolismo , Doenças das Plantas/microbiologiaRESUMO
In eucalyptus plantations, the presence of understory increases the risk of fires, acts as an obstacle to forest operations, and leads to yield losses due to competition. The objective of this study was to develop an approach to discriminate the presence or absence of understory in eucalyptus plantations based on airborne laser scanning surveys. The bimodal canopy height profile was modeled by two Weibull density functions: one to model the canopy, and other to model the understory. The parameters used as predictor in the logistic model successfully discriminated the presence or absence of understory. The logistic model composed by ℽ canopy, ℽ understory, and ℽ understory showed higher values of accuracy (0.96) and kappa (0.92), which means an adequate classification of presence of understory and absence of understory. Weibull parameters could be used as input in the logistic regression to effectively identify the presence and absence of understory in eucalyptus plantation.
Assuntos
Controle de Plantas Daninhas/métodos , Eucalyptus , Árvores , Tecnologia de Sensoriamento RemotoRESUMO
In eucalyptus plantations, the presence of understory increases the risk of fires, acts as an obstacle to forest operations, and leads to yield losses due to competition. The objective of this study was to develop an approach to discriminate the presence or absence of understory in eucalyptus plantations based on airborne laser scanning surveys. The bimodal canopy height profile was modeled by two Weibull density functions: one to model the canopy, and other to model the understory. The parameters used as predictor in the logistic model successfully discriminated the presence or absence of understory. The logistic model composed by ℽ canopy, ℽ understory, and ℽ understory showed higher values of accuracy (0.96) and kappa (0.92), which means an adequate classification of presence of understory and absence of understory. Weibull parameters could be used as input in the logistic regression to effectively identify the presence and absence of understory in eucalyptus plantation.(AU)
Assuntos
Eucalyptus , Árvores , Controle de Plantas Daninhas/métodos , Tecnologia de Sensoriamento RemotoRESUMO
Our goal was to establish the requirement of ß3 adrenoceptor (ß3Adr) for green tea (GT) effects on the energy metabolism of obese mice. This study was carried out in wild-type (WT) and ß3Adr knockout (KO) male mice fed with a standard diet or a high-fat diet (HFD/16 weeks) treated or not with GT (0.5 g/kg of body weight (BW)/12 weeks). GT-treatment attenuated final BW, BW gain, and adiposity index increased by HFD, improving insulin resistance (IR) and FGF21 level, without changing the food intake of WT mice. GT-treatment of ß3AdrKO mice attenuated only IR, denoting GT-effects independent of ß3Adr. We observed increased lipolysis accompanied by decreased adipocyte size in white adipose tissue (WAT) as well as browning of the subcutaneous WAT induced by GT in a way dependent on ß3Adr. In brown adipose tissue (BAT) mRNA levels of lipolytic/oxidative genes, including ß3Adr/Ucp1 and energy expenditure (EE) was increased by GT dependent on ß3Adr. GT-treatment increased adiponectin independent of ß3Adr. Also, independent of ß3Adr pathway GT promoted an increase in ß2Adr/Ucp1 mRNA levels and EE in BAT whereas; in the liver, GT has a dual role in increasing lipid synthesis and oxidation. These data lead us to suggest that GT uses ß3Adr pathway activation to achieve some of its beneficial health effects.
Assuntos
Fármacos Antiobesidade/farmacologia , Camellia sinensis , Metabolismo Energético/efeitos dos fármacos , Obesidade/tratamento farmacológico , Extratos Vegetais/farmacologia , Receptores Adrenérgicos beta 3/deficiência , Adiponectina/genética , Adiponectina/metabolismo , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/patologia , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Tecido Adiposo Branco/patologia , Adiposidade/efeitos dos fármacos , Animais , Fármacos Antiobesidade/isolamento & purificação , Camellia sinensis/química , Dieta Hiperlipídica , Modelos Animais de Doenças , Lipólise/efeitos dos fármacos , Masculino , Camundongos Knockout , Obesidade/genética , Obesidade/metabolismo , Obesidade/patologia , Extratos Vegetais/isolamento & purificação , Receptores Adrenérgicos beta 3/genética , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo , Aumento de Peso/efeitos dos fármacosRESUMO
Clustered regularly interspaced short palindromic repeats (CRISPRs) are composed of an array of short DNA repeat sequences separated by unique spacer sequences that are flanked by associated (Cas) genes. CRISPR-Cas systems are found in the genomes of several microbes and can act as an adaptive immune mechanism against invading foreign nucleic acids, such as phage genomes. Here, we studied the CRISPR-Cas systems in plant-pathogenic bacteria of the Ralstonia solanacearum species complex (RSSC). A CRISPR-Cas system was found in 31% of RSSC genomes present in public databases. Specifically, CRISPR-Cas types I-E and II-C were found, with I-E being the most common. The presence of the same CRISPR-Cas types in distinct Ralstonia phylotypes and species suggests the acquisition of the system by a common ancestor before Ralstonia species segregation. In addition, a Cas1 phylogeny (I-E type) showed a perfect geographical segregation of phylotypes, supporting an ancient acquisition. Ralstoniasolanacearum strains CFBP2957 and K60T were challenged with a virulent phage, and the CRISPR arrays of bacteriophage-insensitive mutants (BIMs) were analysed. No new spacer acquisition was detected in the analysed BIMs. The functionality of the CRISPR-Cas interference step was also tested in R. solanacearum CFBP2957 using a spacer-protospacer adjacent motif (PAM) delivery system, and no resistance was observed against phage phiAP1. Our results show that the CRISPR-Cas system in R. solanacearum CFBP2957 is not its primary antiviral strategy.
Assuntos
Sistemas CRISPR-Cas/genética , Ralstonia solanacearum/genética , Ralstonia solanacearum/virologia , Imunidade Adaptativa/fisiologia , Bacteriófagos/genética , Bacteriófagos/metabolismo , Bacteriófagos/patogenicidadeRESUMO
The surgical treatment of the lesions located in the central lobe is a very difficult task for the neurosurgeon. The overall aim of this study is to verify the correlation of the coronal suture and the structures of the central lobe in 32 cadaver hemisphere brains and the importance of this information in surgical planning. The measurement of the nasion to the coronal suture ranged from 11.5 to 13.5 cm. The distance between the coronal suture in the midline to the central, precentral and paracentral sulcus ranged from 5.0 to 6.6, 2.5 to 4.5 and 1.3 to 4.0 cm respectively. Particularly in the normal cortex these measurements can be used to guide the surgical access. However, the identification of the central sulcus is not easy when the anatomical pattern is distorted or displaced by a lesion or edema. In cases such as these the use of other tools becomes crucial for good surgical planning and cortical mapping or awake craniotomy for a safer resection of the lesion as well.
Assuntos
Suturas Cranianas/anatomia & histologia , Lobo Frontal/anatomia & histologia , Cadáver , Suturas Cranianas/cirurgia , Craniotomia , Lobo Frontal/cirurgia , HumanosRESUMO
The surgical treatment of the lesions located in the central lobe is a very difficult task for the neurosurgeon. The overall aim of this study is to verify the correlation of the coronal suture and the structures of the central lobe in 32 cadaver hemisphere brains and the importance of this information in surgical planning. The measurement of the nasion to the coronal suture ranged from 11.5 to 13.5 cm. The distance between the coronal suture in the midline to the central, precentral and paracentral sulcus ranged from 5.0 to 6.6, 2.5 to 4.5 and 1.3 to 4.0 cm respectively. Particularly in the normal cortex these measurements can be used to guide the surgical access. However, the identification of the central sulcus is not easy when the anatomical pattern is distorted or displaced by a lesion or edema. In cases such as these the use of other tools becomes crucial for good surgical planning and cortical mapping or awake craniotomy for a safer resection of the lesion as well.
O tratamento cirúrgico de lesões localizadas no lobo central é difícil para o neurocirurgião. O objetivo deste estudo é verificar a relação da sutura coronária com as estruturas do lobo central utilizando-se de dissecção realizada em 32 hemisférios cerebrais de 16 cadáveres, assim como, a importância desta informação no planejamento cirúrgico. A medida da distância entre o nasion e a sutura coronária variou entre 11,5 e 13,5 cm. A distância da sutura coronária na linha média para os sulcos central, pré-central e paracentral variou de 5,0 a 6,6 cm, 2,5 a 4,5 cm e 1,3 a 4,0 cm respectivamente. O conhecimento destas medidas pode ser usado no planejamento cirúrgico principalmente num córtex normal. Porém, a identificação do sulco central é difícil quando as estruturas anatômicas estão deslocadas pela lesão ou quando há edema. Nestes casos a utilização de outros meios diagnósticos para o planejamento cirúrgico torna-se necessária, como também a estimulação cortical ou a craniotomia com o paciente acordado pode proporcionar uma ressecção mais segura da lesão.
Assuntos
Humanos , Suturas Cranianas/anatomia & histologia , Lobo Frontal/anatomia & histologia , Cadáver , Craniotomia , Suturas Cranianas/cirurgia , Lobo Frontal/cirurgiaRESUMO
A dieta enteral constitui uma das principais causas de infecção hospitalar, constituindo um importante veículo de contaminação microbiana. Foram analisadas dezoito amostras de dietas enterais líquidas, em unidade hospitalar, sendo seis amostras obtidas diretamente da embalagem original (Tetra Pak), seis adicionadas de água e seis com adição de suplemento (albumina e fibra solúvel). As amostras foram estudadas quanto à presença de diferentes patógenos. Nenhuma amostra avaliada revelou a presença de Escherichia coli. No entanto, a presença de Salmonella foi detectada em 67 por cento das amostras de dieta adicionada de suplementos e 17 por cento das amostras de dieta adicionada de água. A contaminação por Staphylococcus aureus foi evidenciada em 33 por cento da amostras de dieta pura e de dieta adicionada de água e em 17 por cento das amostras de dieta adicionada de suplementos. A contaminação por Coliformes totais foi evidenciada em 33 por cento das amostras de dieta adicionada de suplementos e em 17 por cento da dieta adicionada de água. Níveis não significativos de Bacillus cereus foram encontrados tanto na dieta pura quanto na adicionada de suplemento. Os resultados observados sugerem que medidas de controle higiênico-sanitárias na manipulação das dietas enterais sejam priorizados em unidades hospitalares, a fim de aumentar a segurança alimentar dos pacientes.(AU)
Enteral diet constitutes of the principal causes of hospitalar infection constituting an important vehicle of microbial contamination. Eighteen samples of liquid enteral diets were analyzed in hospitalar, six samples obtained directly of the original packing (Tetra Pak), six enteral diet added of water and six enteral diet added of supplement (albumin and soluble fiber). The samples were analyzed with relationship to the presence of pathogens different. None samples reveal the presence of Escherichia coli. However, the presence of Salmonella was detected in. 67% of the samples of diet added of supplements and 17% of the samples of diet added of water. The contamination for Staphylacaccus aureus was evidenced in. 33% of the pure diet and 33% of diet added of water and in 17% of the diet added f supplements. The contamination for total coliforms was evidenced in 33% of the diet added of, supplements and in 17% of the diet added of water. Levels non significant of Bacillus cereus were found in the pure diet and in the diet with addition of supplements. The observed results suggest that hygienic-sanitary control measures in the manipulation of the enteral diets are prioritired in hospitais, in order to increase the patients' alimentary safety. (AU)
Assuntos
Nutrição Enteral , Serviço Hospitalar de Nutrição , Contaminação de Alimentos , Coliformes , Salmonella/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Bacillus cereus/isolamento & purificaçãoRESUMO
A dieta enteral constitui uma das principais causas de infecção hospitalar, constituindo um importante veículo de contaminação microbiana. Foram analisadas dezoito amostras de dietas enterais líquidas, em unidade hospitalar, sendo seis amostras obtidas diretamente da embalagem original (Tetra Pak), seis adicionadas de água e seis com adição de suplemento (albumina e fibra solúvel). As amostras foram estudadas quanto à presença de diferentes patógenos. Nenhuma amostra avaliada revelou a presença de Escherichia coli. No entanto, a presença de Salmonella foi detectada em 67 por cento das amostras de dieta adicionada de suplementos e 17 por cento das amostras de dieta adicionada de água. A contaminação por Staphylococcus aureus foi evidenciada em 33 por cento da amostras de dieta pura e de dieta adicionada de água e em 17 por cento das amostras de dieta adicionada de suplementos. A contaminação por Coliformes totais foi evidenciada em 33 por cento das amostras de dieta adicionada de suplementos e em 17 por cento da dieta adicionada de água. Níveis não significativos de Bacillus cereus foram encontrados tanto na dieta pura quanto na adicionada de suplemento. Os resultados observados sugerem que medidas de controle higiênico-sanitárias na manipulação das dietas enterais sejam priorizados em unidades hospitalares, a fim de aumentar a segurança alimentar dos pacientes.
Assuntos
Nutrição Enteral , Contaminação de Alimentos , Microbiologia de Alimentos , Serviço Hospitalar de Nutrição , Bacillus cereus/isolamento & purificação , Coliformes , Salmonella/isolamento & purificação , Staphylococcus aureus/isolamento & purificaçãoRESUMO
A avaliação funcional possui grande importância para os amputados, uma vez que a reabilitação deste grupo de pacientes visa melhorar a mobilidade e a independência pessoal. O objetivo deste estudo foi buscar na literatura instrumentos existentes para se avaliar a função em pacientes amputados de membros inferiores e realizar uma análise crítica dos textos selecionados. Foram incluídos 52 artigos publicados no período entre 1985 a 2005, nos idiomas inglês, português, espanhol e francês, nas bases de dados Lilacs, Medline, Pubmed, Cochrane e por meio de busca não eletrônica, a partir das referências dos artigos selecionados. Este estudo demonstrou que existem diversos instrumentos usados para avaliar a função em pacientes amputados, porém não há um considerado padrão-ouro e que instrumentos genéricos não específicos para medir função de amputados são inapropriados para uso com este grupo de pacientes.