RESUMO
The sterol 3ß,5α,6ß,7α-tetrahydroxyergosta-8(14),22-diene was obtained from bio-guided fractioning of the chloroform extract of 50 L of liquid culture of Acremonium persicinum. This fungal strain was selected because of its anti-proliferative activity against solid human tumour cell lines (GI50 ≤ 50 µg/mL) in a bio-prospective study of fungi isolated from plant material, sediment and water samples obtained from alkaline lakes Alchichica and Atexcac in Puebla, Mexico. This compound showed GI50 (µM) values of: 16, 24, 18, 15 and 12 against tumour cell lines A-549, HBL-100, HeLa, T-47D and WiDr respectively. GI50 effects against tumour lines T-47D and WiDr were found to be greater than the clinically used drugs Etoposide and Cisplatin. Because of this, the results obtained support the pharmacological importance of the microorganisms that develop in these ecosystems and strengthen the non-invasive bio-prospection studies that our work group has developed in recent years.
Assuntos
Acremonium , Antineoplásicos/farmacologia , Lagos , Acremonium/química , Antineoplásicos/isolamento & purificação , Linhagem Celular Tumoral , Humanos , Lagos/microbiologia , MéxicoRESUMO
The newly characterized elicitor AsES obtained from Acremonium strictum induces a strong defence response in strawberry plants and confers plants resistance against the fungal pathogen Colletotricum acutatum the casual agent of anthracnose disease. Previous studies showed that AsES causes the accumulation of reactive oxygen species (ROS) that peaked 4 h post treatment (hpt), but due to the experimental approach used it was not clear whether the accumulation of ROS observed was intracellular or extracellular or took place as a single peak. By using a different experimental setup, a more complex early events associated to the activation of the innate immunity were observed. In this paper we report that strawberry plant cells treated with AsES exhibits a triphasic production of H2O2 and a rapid intracellular accumulation of NO. The first phase consists in a progressive extracellular accumulation of H2O2 that starts immediately after the treatment with AsES and is preceded by a rapid and transient cell membrane depolarization. During this phase takes place also a rapid intracellular accumulation of NO. Microscopic observations of mesophyll cells treated with AsES reveals that NO accumulates at the chloroplast. After the first extracellular H2O2 production phase, two intracellular H2O2 accumulation events occur, the first 2 hpt, and the second 7 hpt. Cells treated with AsES also show a transient increase of ion leakage, and a progressive alkalinization of the extracellular medium.
Assuntos
Acremonium/química , Membrana Celular/metabolismo , Fragaria/metabolismo , Proteínas Fúngicas/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Óxido Nítrico/metabolismo , Explosão Respiratória/efeitos dos fármacos , Álcalis/metabolismo , Sulfonatos de Arila/metabolismo , Membrana Celular/efeitos dos fármacos , Respiração Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Espaço Extracelular/efeitos dos fármacos , Espaço Extracelular/metabolismo , Fluorescência , Fragaria/citologia , Fragaria/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Íons , Células do Mesofilo/efeitos dos fármacos , Células do Mesofilo/metabolismo , Suspensões , Fatores de TempoRESUMO
Despite the importance of Acremonium chrysogenum as the only cephalosporin C (CPC) producer, there is still a limited understanding about the molecular mechanisms regulating antibiotic biosynthesis in this fungus. Based on the previously described relationship between environmental pH and antibiotic production in numerous filamentous fungi, we studied the expression of genes related to CPC production in A. chrysogenum. We report for the first time similarities and differences, characterizing CPC production by A. chrysogenum under a variable pH environment, in submerged and solid-state fermentation. This characterization is supported by measurements of parameters, like CPC production, pH, growth, and expression levels of several genes involved, directly or indirectly, in CPC production. Interesting differences in intermediate (Pen N) and certain biosynthetic gene expression levels were observed. Our results point out some relationships between physiological features and gene expression that open important improvement perspectives for both culture systems.
Assuntos
Acremonium/genética , Cefalosporinas/biossíntese , Fermentação , Transcriptoma , Acremonium/química , Meios de Cultura/química , DNA Fúngico/análise , DNA Fúngico/genética , Escherichia coli/química , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Glucosamina/química , Concentração de Íons de Hidrogênio , Micélio/química , Micélio/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
In a screening for antimicrobial metabolites, amides of D-allo- and L-isoleucine derivatives were isolated from the culture of a marine strain of Acremonium furcatum. Structural elucidation of these compounds was performed by analysis of spectroscopic data and confirmed by synthesis. All of the compounds, natural and synthetic intermediates, were bioassayed against bacteria and phytopathogenic fungi, with many showing remarkable antifungal activities.
Assuntos
Acremonium/química , Acremonium/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Bactérias/efeitos dos fármacos , Estrutura MolecularRESUMO
A relatively simple and inexpensive thin-layer chromatographic (TLC) method is described for the detection and semiquantitative measurement of ergovaline in leaf sheaths of tall fescue (Festuca arundinacea). Samples were finely ground and extracted with methanol. The extracts were filtered and the methanol was evaporated. The aqueous residue was extracted with hexane, followed by chloroform at pH 9. The chloroform extract was concentrated and further purified on a preparative silica gel TLC plate, developed with toluene/ethyl acetate/acetonitrile (50:10:40). The ergovaline band was scraped and eluted with methanol. The eluant was concentrated and an aliquot was applied to a silica gel TLC plate. The plate was developed successively with chloroform/acetone/acetic acid (90:10:5) and chloroform/ethanol (9:1). Ergovaline was visualized with p-dimethylaminobenzaldehyde and sulfuric acid. Semiquantitation of ergovaline was achieved by comparison with a known standard of ergotamine, which was shown to have the same Rf as ergovaline in this system. Spike recovery of ergotamine averaged 60%, with a limit of detection of 200 microg/kg of dry tall fescue leaf sheaths. The method was applied to 15 tall fescue samples with varying degrees of fungal infection, and ergovaline was identified in all contaminated samples with endophyte infection above 15%. Thin-layer chromatography may be also applicable for tall fescue seed, where the ergovaline content is usually higher and the amount of interfering pigments is much lower.
Assuntos
Acremonium/patogenicidade , Cromatografia em Camada Fina/veterinária , Ergotaminas/análise , Poaceae/química , Poaceae/microbiologia , Vasoconstritores/análise , Acremonium/química , Doenças dos Animais , Animais , Animais Domésticos , Cromatografia em Camada Fina/métodos , Ergotismo/veterinária , Folhas de Planta/química , Poaceae/intoxicação , Sensibilidade e EspecificidadeRESUMO
Five loline-type alkaloids, the known lolinine, N-formylloline, loline, N-methylloline and the new 5,6-dehydro-N-acetylloline, were characterized from the pooid-grass endophyte-infected Festuca argentina. These compounds are not responsible for the toxicity of the plant, as shown upon i.p. injection into mice. Their probable phytoalexine role and chemotaxonomical significance are discussed.