Accumulation of anthocyanins and characteristics of fruits of blood oranges during cold storage

Este trabalho teve como objetivo avaliar o conteúdo de antocianinas no suco e as características físicas e químicas dos frutos de oito variedades de laranjas sanguíneas e de laranja Valência, e, também, verificar os efeitos do armazenamento dos frutos a 10ºC, durante um período de até 60 dias, nos parâmetros avaliados. Os teores de antocianina foram determinados utilizando-se de um método espectrofotométrico, assim como dez características físicas e químicas dos frutos e dos sucos foram avaliadas antes e durante o armazenamento. Todas as variedades de laranja avaliadas apresentaram naturalmente baixos teores ou nenhum teor de antocianina no suco. O armazenamento durante um período de até 60 dias, em baixa temperatura, possibilitou acúmulo significativo de antocianina no suco, porém de maneira desigual nas variedades de laranjas sanguíneas testadas. As variedades Moro foram as que apresentaram suco contendo os maiores teores de antocianina no final do armazenamento. À exceção de duas variedades, Sanguinelli (Marrocos e Polidari), as demais variedades sanguíneas avaliadas podem ser consideradas como semelhantes entre si e adequadas ao consumo. O armazenamento dos frutos a 10ºC, durante o período máximo de 60 dias, alterou significativamente somente as variáveis: largura de frutos, teor de SS, acidez e o rendimento de suco.The aim of this study was to assess the content of anthocyanins in the juice and the physical and chemical characteristics of the fruit of eight blood orange varieties and of orange Valencia, and also verify the effects of storage of fruits at 10ºC, for a period of up to 60 days, in the same parameters. The anthocyanin content was determined using a spectrofotometric method and ten physical and chemical characteristics of the fruits and juice were also evaluated before and during the storage. Under natural conditions all varieties showed fruits with low anthocyanin content in the juice. Cold storage during a period of up to 60 days enables a significant accumulation of anthocyanin in the juice, but in a different level in the evaluated blood orange varieties. Moro is the variety that showed the highest anthocyanin content in the end of the storage period. Except for two Sanguinelli varieties (Morocco and Polidari), the other varieties can be considered as similar as others and suitable for consumption. The storage of fruits to 10ºC during the maximum period of 60 days significantly modifies only fruit width, juice content in fruits, soluble solids content and acidity of the juice

Evidences of siderophores synthesis by Grapevine Xylella fastidiosa, causal agent of pierce's disease, through instrumental approaches

Siderophore molecules from grapevine Xylella fastidiosa were investigated. Such metabolites sequester iron, an essential element, from the host, making them a potential factor of pathogenicty. In an iron-limited medium, siderophores were detected in culture plates of X. fastidiosa containing the complex Chromeazurol S (CAS). A combination of different instrumental analyses was used for siderophore(s) characterization, such as: immobilized metal affinity chromatography (IMAC), micelar electrokinetic capillary chromatography (MEKC) and electrospray-mass spectrometry (ESI-MS). The results show that grapevine X. fastidiosa produced siderophore(s), as confirmed by the CAS plate assay. The extraction of the compound(s) using IMAC with immobilized Fe3+ was important for analyte purification. The chelator was not separated by capillary zone electrophoresis, indicating the possibility of a neutral compound under the investigated pHs. MEKC runs presented a different peak (when compared to the control analysis) which represented a slightly hydrophobic compound. Mass spectrometry showed that the compound(s) may have a relative molecular mass within the expected range for siderophore molecules, such as 875, 1004 and 1092 Da

Evidences of siderophores synthesis by Grapevine Xylella fastidiosa, causal agent of pierce's disease, through instrumental approaches

Siderophore molecules from grapevine Xylella fastidiosa were investigated. Such metabolites sequester iron, an essential element, from the host, making them a potential factor of pathogenicty. In an iron-limited medium, siderophores were detected in culture plates of X. fastidiosa containing the complex Chromeazurol S (CAS). A combination of different instrumental analyses was used for siderophore(s) characterization, such as: immobilized metal affinity chromatography (IMAC), micelar electrokinetic capillary chromatography (MEKC) and electrospray-mass spectrometry (ESI-MS). The results show that grapevine X. fastidiosa produced siderophore(s), as confirmed by the CAS plate assay. The extraction of the compound(s) using IMAC with immobilized Fe3+ was important for analyte purification. The chelator was not separated by capillary zone electrophoresis, indicating the possibility of a neutral compound under the investigated pHs. MEKC runs presented a different peak (when compared to the control analysis) which represented a slightly hydrophobic compound. Mass spectrometry showed that the compound(s) may have a relative molecular mass within the expected range for siderophore molecules, such as 875, 1004 and 1092 Da.Os sideróforos provenientes de Xylella fastidiosa de videiras foram investigados. Tais metabólitos seqüestram ferro, um elemento essencial, do hospedeiro, o que os torna um potencial fator de patogenicidade. Em um meio de cultura em placa com limitação de ferro, tais sideróforos foram detectados pela reação com o complexo cromoazurol S (CAS). Diferentes métodos de análise instrumentais foram utilizados para caracterização dos sideróforos, como: cromatografia de afinidade por metal imobilizado (IMAC), cromatografia micelar eletrocinética capilar (MEKC) e espectrometria de massas com ionização por electrospray (ESI-MS). Os resultados obtidos confirmaram a produção de sideróforos. A extração do(s) composto(s) por IMAC com Fe3+ imobilizado foi uma etapa importante. O(s) sideróforo(s) não foi separado por eletroforese capilar de zona, indicando sua neutralidade sob os pHs investigados. As análises por MEKC apresentaram um pico diferente (quando comparadas à análise do controle), com caráter levemente hidrofóbico. A espectrometria de massas mostrou que os compostos alvos podem ter uma massa molecular relativa dentro da esperada para sideróforos, como: 875, 1004 e 1092 Da.635641Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Hepatotoxin microcystin-LR extraction optimization

Several cyanobacterial genera produce toxic secondary metabolites, the most well-known of which are the hepatotoxic microcystins (MCYSTs). Microcystin analyses in drinking water are a requirement of the Health Ministry (Regulation 518/2004) in Brazil, but this regulation does not establish which extraction and analytical method should be used; toxin quantification is usually carried out by ELISA (enzyme-linked immunosorbent assay) or HPLC (high performance liquid chromatography), the efficiency of which depends on the extraction method used. In this work a simple, fast and cheap method of extraction was developed for the isolation and identification of MCYSTs. For this, the strain Microcystis aeruginosa NPLJ-4, reported to be a MCYST-LR producer, was selected. Eight different treatments were tested to determine the best MCYST extraction. Samples were applied in LC-MS (liquid chromatography-mass spectrometry), ELISA and Q-TOF (quadrupole time-of-flight). The most efficient extraction was achieved by sonicating samples diluted in water. The proposed method permits rapid sample processing, and establishes an extraction method for both the analysis and identification of MCYST-LR and other variants.Vários gêneros de cianobactérias produzem metabólitos secundários tóxicos, entre eles as hepatotoxinas microcistinas. A análise de microcistinas em águas para abastecimento humano é uma exigência do Ministério da Saúde (Portaria 518/2004), mas essa portaria ainda não estabelece o método de extração e análise a serem usados e a quantificação da toxina é comumente realizada por ELISA ("enzyme-linked immunosorbent assay") ou HPLC (cromatografia líquida de alta eficiência), cuja eficiência depende do método de extração utilizado. Neste trabalho foi desenvolvido um método simples, rápido e barato de extração para o isolamento e identificação de microcistinas. Para isso, selecionou-se a linhagem Microcystis aeruginosa NPLJ-4 descrita como produtora de microcistina-LR. Oito diferentes tratamentos foram testados para determinar a melhor extração da toxina. As amostras foram analisadas por LC-MS (cromatografia líquida acoplada a espectrometria de massas), ELISA e Q-TOF ("quadrupole time-of-flight"). Os resultados mostraram que a melhor extração foi a que usou sonicação das amostras diluídas em água. O método proposto permite o processamento rápido das amostras e estabelece um método de extração para análise e identificação de microcistina-LR e outras variantes.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Composto antifúngico produzido pelo endófito de mandioca Bacillus pumilus MAIIIM4a

Na busca de novos organismos e novos metabólitos secundários, um estudo foi conduzido visando avaliar a diversidade de bactérias endofíticas de etnovariedades de mandioca cultivadas por tribos indígenas da Amazônia brasileira e também para estudar metabólitos secundários produzidos por Bacillus pumilus. Sessenta e sete bactérias endofíticas de mandioca foram identificadas através do seqüenciamento do gene 16S rRNA e por meio da análise de ácidos graxos (FAME). Essas análises revelaram que 25% de todos os endofíticos pertenciam ao gênero Bacillus. O isolado Bacillus pumilus MAIIIM4a apresentou forte ação inibitória contra os fitopatógenos Rhizoctonia solani, Pythium aphanidermatum e Sclerotium rolfsii. Os metabólitos secundários deste isolado foram extraídos do sobrenadante usando-se hexano, diclorometano e acetato de etila. Esses extratos foram utilizados nas análises de bioautografia e LC-MS, as quais permitiram a identificação do composto pumilacidina, um antifúngico produzido por B. pumilus MAIIIM4a. A localização das bactérias endofíticas foi confirmada examinando-se o tecido celular da mandioca através de microscopia eletrônica.In the search for new organisms and new secondary metabolites, a study was conducted to evaluate the diversity of endophytic bacteria from ethnovarieties of cassava cultivated by Brazilian Amazon Indian tribes and also to study the secondary metabolites produced by a Bacillus pumilus strain. Sixty seven cassava endophytic bacteria were subjected to 16S rRNA sequencing and FAME analysis. The bacterial profile revealed that 25% of all endophytic isolates belonged to the genus Bacillus. The isolate B. pumilus MAIIIM4a showed a strong inhibitory activity against the fungi Rhizoctonia solani, Pythium aphanidermatum and Sclerotium rolfsii. Secondary metabolites of this strain were extracted using hexane, dichloromethane and ethyl acetate. Extracts were subjected to bioautography and LC/MS analysis, which allowed the identification of pumilacidin, an antifungal compound produced by B. pumilus MAIIIM4a. The bacterial endophytic localization was confirmed by cassava cell tissue examination using scanning electron microscopy

Quorum Sensing Detected By Atomic Force Microscopy Imaging Of Corrals Surrounding Multicellular Arrangement Of Bacteria.

Connectivity of the glycocalyx covering of small communities of Acidithiobacillus ferrooxidans bacteria deposited on hydrophilic mica plates was imaged by atomic force microscopy. When part of the coverage was removed by water rinsing, an insoluble structure formed by corrals surrounding each individual bacterium was observed. A collective ring structure with clustered bacteria (>or=3) was observed, which indicates that the bacteria perceived the neighborhood in order to grow a protective structure that results in smaller production of exopolysaccharides material. The most surprising aspect of these collective corral structures was that they occur at a low bacterial cell density. The deposited layers were also analyzed by confocal Raman microscopy and shown to contain polysaccharides, protein, and glucoronic acid.71112-