Polyketide synthases (PKSs) and/or nonribosomal peptide synthetases (NRPSs) are central components of secondary metabolism in bacteria, plants, and fungi. In filamentous fungi, diverse PKSs and NRPSs participate in the biosynthesis of secondary metabolites such as pigments, antibiotics, siderophores, and mycotoxins. However, many secondary metabolites as well as the enzymes involved in their production are yet to be discovered. Both PKSs and NRPSs require activation by enzyme members of the 4-phosphopantetheinyl transferase (PPTase) family. Here, we report the isolation and characterization of Aspergillus nidulans strains carrying conditional (cfwA2) and null (⌬cfwA) mutant alleles of the cfwA gene, encoding an essential PPTase. We identify the polyketides shamixanthone, emericellin, and dehydroaustinol as well as the sterols ergosterol, peroxiergosterol, and cerevisterol in extracts from A. nidulans large-scale cultures. The PPTase CfwA/NpgA was required for the production of these polyketide compounds but dispensable for ergosterol and cerevisterol and for fatty acid biosynthesis. The asexual sporulation defects of cfwA, ⌬fluG, and ⌬tmpA mutants were not rescued by the cfwA-dependent compounds identified here. However, a cfwA2 mutation enhanced the sporulation defects of both ⌬tmpA and ⌬fluG single mutants, suggesting that unidentified CfwA-dependent PKSs and/or NRPSs are involved in the production of hitherto-unknown compounds required for sporulation. Our results expand the number of known and predicted secondary metabolites requiring CfwA/NpgA for their biosynthesis and, together with the phylogenetic analysis of fungal PPTases, suggest that a single PPTase is responsible for the activation of all PKSs and NRPSs in A. nidulans.Filamentous fungi represent a rich and diverse source of bioactive compounds derived from secondary metabolism. Indeed, many positive and negative effects that fungi have on human activity are mediated by secondary metabolites such as antibiotics and other pharmaceutical drugs, mycotoxins, or pathogen virulence factors (22, 30, 54-56, 60, 66). In contrast to primary metabolism, common to most living organisms, secondary metabolism is not essential for the immediate survival of the producing organism. Furthermore, different taxonomic groups produce different types of secondary metabolites.Despite their large chemical diversity, secondary metabolites can be grouped according to their primary metabolism precursors. Acetyl coenzyme A, shikimate, and amino acids are major secondary metabolite building units. Acetyl coenzyme A is used to produce terpenoids, steroids, carotenoids, and polyketides.
There are many species of endemic plants from Mexico, without food or commercial use, but with different applications in traditional medicine and valuable for their content of secondary metabolites. In this sense, we found two species of Cucurbitacea family plants natives of southeast and gulf of México, with traditionally use how soap and laundry agent, control of some pests, and it has also been used how infusion for the treatment of different types of dermatitis and stomachache. In the present work, we evaluate the antiproliferative activity in vitro, of six crude organic extracts, tested against six human tumor cell lines, A549 (lung), HBL-100 (breast), HeLa (cervix), SW1573 (lung), T-47D (breast) and WiDr (colon), the results indicated that at least three extracts from both species presents an interesting antiproliferative activity on five tumor cell lines.
Red algae of Laurencia continue to provide wide structural diversity and complexity of halogenated C15 acetogenin medium-ring ethers. Here, we described the isolation of three new C15 acetogenins (3–5), and one truncated derivative (6) from Laurencia viridis collected on the Canary Islands. These compounds are interesting variations on the pinnatifidenyne structure that included the first examples of ethynyl oxirane derivatives (3–4). The structures were elucidated by extensive study of NMR (Nuclear Magnetic Resonance) data, J-based configuration analysis and DFT (Density Functional Theory) calculations. Their antiproliferative activity against six human solid tumor cell lines was evaluated.
RESUMENC inco compuestos de una cepa comercial del hongo Pleurotus sp. se obtuvieron a partir de extracciones con acetato de etilo y metanol. Los compuestos se aislaron por medio de técnicas como la cromatografía en columna y en capa fina. Los siguientes esteroles fueron identificados mediante espectroscopía RMN 1 H: 1) ergosta-5, 7, 22-trien-3β-ol (ergosterol), 2) 5α, 8α-epidioxi-22E-ergosta-6, 22-dien-3β-ol (peróxido de ergosterol), 3) 3β, 5α, 6β, 9α-tetrahidroxiergosta-7, 22-dieno, 4) 3β, 5α, 6β, 9α-tetrahydroxyergosta-7, 22-dien y 5) 3β, 5α, 9α-trihidroxiergosta-7, 22-dien-6-ona. ABSTRACTF ive compounds in a commercial strain of the mushroom Pleurotus sp. were obtained from ethyl acetate and methanol extracts. The compounds were isolated using techniques such as column and thin layer chromatography. The following sterols were identified by 1 H NMR spectroscopy: 1) ergosta-5,7,22-trien-3β-ol (ergosterol), 2) 5α, 8α-epidioxy-22E-ergosta-6, 22-dien-3β-ol (ergosterol peroxide), 3) 3β,5α,6β,9α-tetrahidroxiergosta-7,22-dieno, 4) 3β, 5α, 6β, 9α-tetrahydroxyergosta-7, 22-dien and 5) 3β, 5α, 9α-trihidroxiergosta-7,22-dien-6-one.
de Tlaxcala. km 10.5 Autopista San Martín Texmelucan-Tlaxcala. C. P. 90122. Ixtacuixtla, Tlax. RESUMENL os hongos micorrizógenos se encuentran en asociación con las raíces de muchas plantas, incluyendo casi todas las especies de árboles como la familia Pinaceae. Algunos derivados triterpé-nicos de lanosterol se han aislado tanto del micelio como de los cuerpos fructíferos del hongo ectomicorrizógeno Pisolithus arhizus. En el presente trabajo, se cultivó una cepa de la especie P. arhizus, aislada de bosques de pino en Oaxaca en condiciones de laboratorio, con el fin de determinar qué tipo de compuestos se pueden encontrar en una cepa mexicana cultivada bajo condiciones asimbió-ticas y sus posibles implicaciones ecológicas. Los resultados confirman que, en la fermentación líquida in vitro del micelio, la cepa aislada de los bosques de México presenta el mismo tipo de triterpenos sin funcionalidad con el carbono-23 como otras cepas procedentes de bosques de Europa y Brasil, a pesar de que se utilizó un medio de cultivo PDA en lugar del medio de cultivo Melin-Norkrans. ABSTRACTM ycorrhizal fungi can be found in association with the roots of many plants, including almost all tree species such as the Pinaceae family. Some triterpene derivatives of lanosterol have been isolated both in the mycelium as well as in the fruiting bodies of the ectomycorrhizal fungus Pisolithus arhizus. In order to determine, what type of compounds can be found as well as any possible ecological implications involved in the case of a Mexican strain cultivated under asymbiotic conditions in the present research work, a strain isolated from P. arhizus from pine woods from Oaxaca was grown under laboratory conditions. These results confirm that the strain isolated from the forests of Mexico presents the same type of triterpenes unfunctionalized at carbon-23 in the in vitro liquid fermentation of mycelium, like other strains from forests in Europe and Brazil, despite the fact that they we used a PDA medium culture instead of a half Melin-Norkrans medium culture.
Antecedentes: El género Fusarium produce metabolitos secundarios como las micotoxinas y pigmentos. Dichos pigmentos presentan actividad biológica antibiótica, antiparasitaria, e insecticida y han sido utilizados en la identificación taxonómica. Objetivos: Aislar e identificar los hongos obtenidos del Hemíptero Bemisia aff. tabaci, parasitando una especie de cucurbitácea e identificar los pigmentos producidos por estas especies. Métodos: Se recolectaron insectos muertos de Bemisia aff. tabaci sobre frutos y hojas de una cucurbitácea arvense. El aislamiento fúngico se realizó mediante la colocación directa de los insectos, previamente desinfectados, en cajas Petri con medio PDA. Fueron incubados a 25 °C con un ciclo de 12 horas de luz y 12 horas de oscuridad. La extracción de los pigmentos de las cepas se obtuvo con acetato de etilo. La observación de los pigmentos se realizó mediante cromatografía en capa delgada (CCD), los extractos completos fueron analizados mediante resonancia magnética nuclear de protones (1HNMR). Resultados y conclusiones: Se aislaron e identificaron Fusarium avenaceum y F. oxysporum. Estas cepas produjeron tres y dos compuestos, respectivamente, que mediante comparación de las señales identificadas en el espectro de 1HNMR, con las reportadas en la literatura, podemos suponer que corresponden a pigmentos de tipo xantona y antraquinona de color rojo-vino.
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