RESUMO
Canastra cheese is a cheese with geographical indication recognized by the Brazilian National Institute of Industrial Protection under number IG201002. It is produced in seven municipalities in the state of Minas Gerais in a region called Serra da Canastra. In this work, samples of milk, "pingo" (natural starter), whey and Canastra cheese were collected on a farm in Medeiros-MG/Brazil to evaluate the yeast microbiota and select yeasts for whey fermentation to produce ethanol and volatile aromatic compounds of relevance in the production of cheese. Thirty-nine isolates capable of fermenting lactose in a synthetic medium were identified by MALDI-TOF as Kluyveromyces lactis (29), Torulaspora delbrueckii (7) and Candida intermedia (3). Eleven isolates of K. lactis and three of T. delbrueckii efficiently fermented lactose until 4th day, and due to this reason were selected for cheese whey fermentation with Brix 12, 14 and 18. Generally, the isolates T. delbrueckii B14, B35, and B20 and K. lactis B10 were the most effective regardless of the initial Brix value. The identification of these four isolates by MALDI TOF was confirmed by sequencing of the ITS region. In the fermentation of cheese whey 14 Brix, T. delbrueckii B14 and B35, respectively yielded 24.06g/L and 16.45g/L of ethanol, while K. lactis B10 was more efficient in the consumption of lactose. In sequential culture with K. lactis B10 inoculated 48h after T. delbrueckii B14, 97.82% of the total sugars were consumed resulting in the production of 19.81g/L ethanol and 39 aromatic volatile compounds. The most abundant compounds were 3-methyl-1-butanol, octanoic acid and ethyl decanoate, which are reported as important for the aroma and flavor of cheeses. Based in our results, B10 isolate inoculated 48h after B14 isolate is a promising yeast inoculum to be used for fermentation of dairy substrates.
Assuntos
Queijo/microbiologia , Fermentação , Manipulação de Alimentos/métodos , Microbiologia de Alimentos/métodos , Soro do Leite/microbiologia , Leveduras/metabolismo , Brasil , Caprilatos/metabolismo , Decanoatos/metabolismo , Kluyveromyces/metabolismo , Lactose/metabolismo , Odorantes , Pentanóis/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Paladar , Torulaspora/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Leveduras/classificação , Leveduras/isolamento & purificaçãoRESUMO
This study identified chemicals found on the eggs of two stink bug species, one native to western North America, Euschistus conspersus, and an invasive species from Asia, Halyomorpha halys. The responses of two scelionid egg parasitoids, Trissolcus erugatus and Telenomus podisi, toward natural stink bug egg volatiles, and synthetic reconstructions of egg volatiles, were tested in bioassays. A compound, methyl (2E,4Z)-2,4-decadienoate, previously identified as the major component of the male-produced aggregation pheromone of E. conspersus, was the major volatile identified from extracts of E. conspersus eggs. In contrast, for H. halys, the sesquiterpenoids that compose the male-produced aggregation pheromone of this species were not detected on eggs, whereas the presence of hexadecanal, octadecanal, and eicosanal was detected. In laboratory olfactometer tests, both Tr. erugatus and Te. podisi females were attracted to extracts of E. conspersus eggs, and to synthetic methyl (2E,4Z)-2,4-decadienoate. However, female Tr. erugatus and Te. podisi wasps were repelled, both by extracts of H. halys eggs and by a blend of the aldehydes identified from H. halys eggs. A follow-up field study, using hexane-washed and intact E. conspersus as sentinel eggs, showed that the parasitoids Trissolcus erugatus and Gryon obesum emerged from these eggs. Sentinel hexane-washed eggs treated with 3 ng of methyl (2E,4Z)-2,4-decadienoate were parasitized more by these two species than were hexane-washed or unwashed eggs, whereas hexane-washed eggs treated with a comparable dose of the C16,18,20 aldehyde mixture were avoided by these parasitoids. In a further field experiment, Trissolcus basalis was the primary parasitoid found in sticky traps baited with methyl (2E,4Z)-2,4-decadienoate, indicating that this species was attracted to, but either did not oviposit or develop in the E. conspersus sentinel eggs in the previous experiment.
Assuntos
Heterópteros/parasitologia , Óvulo/parasitologia , Vespas/fisiologia , Animais , Decanoatos/análise , Decanoatos/metabolismo , Feminino , Heterópteros/química , Heterópteros/fisiologia , Interações Hospedeiro-Parasita , Masculino , Oviposição , Óvulo/química , Óvulo/fisiologia , Controle de Pragas , Feromônios/análise , Feromônios/metabolismo , Olfato , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo , Vespas/anatomia & histologiaRESUMO
Rhamnolipids produced by Pseudomonas aeruginosa are biosurfactants with a high biotechnological potential, but their extensive commercialization is limited by the potential virulence of P. aeruginosa and by restrictions in producing these surfactants in heterologous hosts. In this work, we report the characterization of P. aeruginosa strain ATCC 9027 in terms of its genome-sequence, virulence, antibiotic resistance, and its ability to produce mono-rhamnolipids when carrying plasmids with different cloned genes from the type strain PAO1. The genes that were expressed from the plasmids are those coding for enzymes involved in the synthesis of this biosurfactant (rhlA and rhlB), as well as the gene that codes for the RhlR transcriptional regulator. We confirm that strain ATCC 9027 forms part of the PA7 clade, but contrary to strain PA7, it is sensitive to antibiotics and is completely avirulent in a mouse model. We also report that strain ATCC 9027 mono-rhamnolipid synthesis is limited by the expression of the rhlAB-R operon. Thus, this strain carrying the rhlAB-R operon produces similar rhamnolipids levels as PAO1 strain. We determined that strain ATCC 9027 with rhlAB-R operon was not virulent to mice. These results show that strain ATCC 9027, expressing PAO1 rhlAB-R operon, has a high biotechnological potential for industrial mono-rhamnolipid production.
Assuntos
Decanoatos/metabolismo , Engenharia Metabólica , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidade , Ramnose/análogos & derivados , Tensoativos/metabolismo , Animais , Modelos Animais de Doenças , Farmacorresistência Bacteriana , Genoma Bacteriano , Redes e Vias Metabólicas/genética , Camundongos , Óperon , Plasmídeos , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , Ramnose/metabolismo , Análise de Sequência de DNA , VirulênciaRESUMO
This work describes the structural elucidation of the sex pheromone of the soybean stink bug, Pallantia macunaima. The biological activity of the synthetic pheromone was demonstrated by behavioral and EAD experiments. Furthermore, the absolute configuration of the natural pheromone was determined as (6R,10S)-6,10,13-trimethyltetradecan-2-one. This is the first ketone identified as a male-produced sex pheromone in Pentatomidae, and the trivial name, pallantione, was assigned to this novel pheromone molecule.
Assuntos
Decanoatos/isolamento & purificação , Hemípteros/química , Atrativos Sexuais/isolamento & purificação , Animais , Decanoatos/química , Decanoatos/metabolismo , Hemípteros/fisiologia , Masculino , Estrutura Molecular , Feromônios/química , Atrativos Sexuais/química , Atrativos Sexuais/metabolismo , EstereoisomerismoRESUMO
The accumulation of octanoic (OA) and decanoic (DA) acids in tissue is the common finding in medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD), the most frequent defect of fatty acid oxidation. Affected patients present hypoketotic hypoglycemia, rhabdomyolysis, hepatomegaly, seizures and lethargy, which may progress to coma and death. At present, the pathophysiological mechanisms underlying hepatic and skeletal muscle alterations in affected patients are poorly known. Therefore, in the present work, we investigated the in vitro effects of OA and DA, the accumulating metabolites in MCADD, on various bioenergetics and oxidative stress parameters. It was verified that OA and DA decreased complexes I-III, II-III and IV activities in liver and also inhibit complex IV activity in skeletal muscle. In addition, DA decreased complexes II-III activity in skeletal muscle. We also verified that OA and DA increased TBA-RS levels and carbonyl content in both tissues. Finally, DA, but not OA, significantly decreased GSH levels in rat skeletal muscle. Our present data show that the medium-chain fatty acids that accumulate in MCADD impair electron transfer through respiratory chain and elicit oxidative damage in rat liver and skeletal muscle. It may be therefore presumed that these mechanisms are involved in the pathophysiology of the hepatopathy and rhabdomyolysis presented by MCADD-affected patients.
Assuntos
Caprilatos/metabolismo , Decanoatos/metabolismo , Fígado/metabolismo , Músculo Esquelético/metabolismo , Estresse Oxidativo , Acil-CoA Desidrogenase/deficiência , Acil-CoA Desidrogenase/metabolismo , Animais , Caprilatos/farmacologia , Creatina Quinase/metabolismo , Decanoatos/farmacologia , Transporte de Elétrons , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Glutationa/metabolismo , Erros Inatos do Metabolismo Lipídico/metabolismo , Fígado/efeitos dos fármacos , Fígado/enzimologia , Masculino , Mitocôndrias/metabolismo , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/enzimologia , Oxirredução , Carbonilação Proteica , Ratos , Ratos Wistar , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Pseudomonas aeruginosa produces rhamnolipids which are tenso-active compounds with potential industrial and environmental applications. There are two main types of rhamnolipids produced in liquid cultures, rhamnosyl-beta-hydroxydecanoyl-beta-hydroxydecanoate (mono-rhamnolipid) and rhamnosyl-rhamnosyl-beta-hydroxydecanoyl-beta-hydroxyd ecanoate (di-rhamnolipid). In this work we report the selective isolation of a rhamnolipid deficient mutant (IBT8), which does not accumulate mono-rhamnolipid while still producing di-rhamnolipid. IBT8 was selected after random mutagenesis with Tn501; yet, its mono-rhamnolipid deficiency was found associated neither with its Tn501 insertion nor with a possible alteration in the rhlABRI genes for rhamnosyl-transferase 1 synthesis. Different possibilities to explain IBT8 phenotype are discussed.