Publicaciones Narváez Trujillo Elizabeth Alexandr

Biatriospora (Ascomycota:Pleosporales) Is An Ecologically Diverse Genus Including Facultative Marine Fungi And Endophytes With Biotechnological Potencial.
REVISTA
PLANT SYSTEMATICS AND EVOLUTION

Publicación
2017-01-01
Biatriospora (Ascomycota: Pleosporales, Biatriosporaceae) is a genus with unexplored diversity and poorly known ecology. This work expands the Biatriospora taxonomic and ecological concept by describing four new species found as endophytes of woody plants in temperate forests of the Czech Republic and in tropical regions, including Amazonia. Ribosomal DNA sequences, together with protein-coding genes (RPB2, EF1a), growth rates and morphology, were used for species delimitation and description. Ecological data gathered by this and previous studies and the inclusion of sequences deposited in public databases show that Biatriospora contains species that are endophytes of angiosperms in temperate and tropical regions as well as species that live in marine or estuarine environments. These findings show that this genus is more diverse and has more host associations than has been described previously. The possible adaptations enabling the broad ecological range of these fungi are discussed. Due to the importance that Biatriospora species have in bioprospecting natural products, we suggest that the species introduced here warrant further investigation

Biosynthesis And Genomic Analysis Of Medium-Chain Hydrocarbon Production By The Endophytic Fungal Isolate Nigrograna Mackinnonii E5202H.
REVISTA
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

Publicación
2015-02-12
An endophytic fungus was isolated that produces a series of volatile natural products, including terpenes and odd chain polyenes. Phylogenetic analysis of the isolate using five loci suggests that it is closely related to Nigrograna mackinnonii CBS 674.75. The main component of the polyene series was purified and identified as (3E,5E,7E)-nona- 1,3,5,7-tetraene (NTE), a novel natural product. Nonoxygenated hydrocarbons of this chain length are uncommon and desirable as gasoline-surrogate biofuels. The biosynthetic pathway for NTE production was explored using metabolic labeling and gas chromatography time of flight mass spectometer (GCMS). Two-carbon incorporation 13C acetate suggests that it is derived from a polyketide synthase (PKS) followed by decarboxylation. There are several known mechanisms for such decarboxylation, though none have been discovered in fungi. Towards identifying the PKS responsable for the production of NTE, the genome of N. mackinnonii E5202H (ATCC SD-6839) was sequenced and assembled. Of the 32 PKSs present in the genome, 17 are predicted to contain sufficient domains for the production of NTE. These results exemplify the capacity of endophytic fungi to produce novel natural products that may have many uses, such as biologically derived fuels and commodity chemicals.

Celulasas Presentes En El Tracto Digestivodel Camarón Litopenaeus Vannamei.
REVISTA
REVISTA ECUATORIANA DE MEDICINA Y CIENCIAS BIOLÓGICAS

Publicación
2015-08-28
Las celulasas han sido clasificadas como endoglucanasas responsables de degradar celulosa, lo que le proporciona gran importancia en los procesos de la cadena alimentaria. Las celulasas y enzimas relacionadas son utilizadas ampliamente en varios procesos industriales. La celulosa es utilizada como una fuente nutricional por varios organismos, inicialmente se pensaba que únicamente microorganismos podrían degradarla, pero en la actualidad se ha encontrado celulasas en varios grupos de animales. En este trabajo, presentamos la detección de celulasas en extractos obtenidos del camarón Litopenaeus vannamei. En los ensayos se utilizaron individuos adultos y de los diferentes subestadios de L. vannamei colectados en los estanques de cría de las camaroneras de la Península de Santa Elena y Muisne, en las provincias de Santa Elena y Esmeraldas, respectivamente. Los hepatopáncreas, los estadios larvarios y los intestinos fueron homogeneizados en un homogeneizador Braun-Melsungen. Para la identificación de la celulasa, se utilizó como sustrato carboximetil celulosa (CMC) de mediana viscosidad. Para medir su actividad se añadió ácido 3,5 dinitrosalicílico (DNS). La actividad de la celulasa se determinó en base en la cantidad de los grupos reductores liberados. Para intentar determinar el origen sea endógeno o microbiano de las celulasas identificadas, se sometieron las muestras de adultos a antibióticos. En el subestadio zoea 3, se identificó una celulasa con un rango de pH óptimo entre pH 6.5 y pH 9.5.

Fusaric Acid Induces A Notochord Malformation In Zebrafish Via Copper Chelation.
REVISTA
BIOMETALS

Publicación
2015-04-26
Over a thousand extracts were tested for phenotypic effects in developing zebrafish embryos to identify bioactive molecules produced by endophytic fungi. One extract isolated from Fusarium sp., a widely distributed fungal genus found in soil and often associated with plants, induced an undulated notochord in developing zebrafish embryos. The active compound was isolated and identified as fusaric acid. Previous literature has shown this phenotype to be associated with copper chelation from the active site of lysyl oxidase, but the ability of fusaric acid to bind copper ions has not been well described. Isothermal titration calorimetry revealed that fusaric acid is a modest copper chelator with a binding constant of 4.4 9 105 M-1. These results shed light on the toxicity of fusaric acid and the potential teratogenic effects of consuming plants infected with Fusarium sp.

Identification Of A Fungal 1,8-Cineole Synthase From Hypoxylon Sp. With Common Specificity Determinants To The Plant Synthases.
REVISTA
JOURNAL OF BIOLOGICAL CHEMISTRY

Publicación
2015-02-03
Background: 1,8-Cineole, a commercially important monoterpene, was identified as a fungal product. Results: The 1,8-cineole synthase was identified from a Hypoxylon fungal genome, and mutagenesis revealed a critical asparagine residue. Conclusion: The fungal 1,8-cineole synthase uses a mechanism similar to the plant version. Significance: This is the first identified fungal monoterpene synthase and may facilitate future terpene synthase identification and production.

The Biological Diversity And Production Of Volatile Organic Compounds By Stem-Inhabiting Endophytic Fungi Of Ecuador.
REVISTA
JOURNAL OF FUNGI

Publicación
2016-12-01
Fungal endophytes colonize every major lineage of land plants without causing apparent harm to their hosts. Despite their production of interesting and potentially novel compounds, endophytes—particularly those inhabiting stem tissues—are still a vastly underexplored component of microbial diversity. In this study, we explored the diversity of over 1500 fungal endophyte isolates collected from three Ecuadorian ecosystems: lowland tropical forest, cloud forest, and coastal dry forest. We sought to determine whether Ecuador’s fungal endophytes are hyperdiverse, and whether that biological diversity is reflected in the endophytes’ chemical diversity. To assess this chemical diversity, we analyzed a subset of isolates for their production of volatile organic compounds (VOCs), a representative class of natural products. This study yielded a total of 1526 fungal ITS sequences comprising some 315 operational taxonomic units (OTUs), resulting in a non-asymptotic OTU accumulation curve and characterized by a Fisher’s α of 120 and a Shannon Diversity score of 7.56. These figures suggest that the Ecuadorian endophytes are hyperdiverse. Furthermore, the 113 isolates screened for VOCs produced more than 140 unique compounds. These results present a mere snapshot of the remarkable biological and chemical diversity of stem-inhabiting endophytic fungi from a single neotropical country.

Total Petroleum Hydrocarbon Degradation By Endophytic Fungi From The Ecuadorian Amazon
REVISTA
ADVANCES IN MICROBIOLOGY

Publicación
2018-12-29
The capacity of 133 fungal endophyte isolates for degrading petroleum hydrocarbons was evaluated. The endophytes were isolated from leaf and stem tissues from 23 plants collected in a natural habitat contaminated with crude oil in southwestern Ecuador. Their capacity for hydrocarbon biodegradation was tested by an in vitro colorimetric qualitative test during 10 days, using the Minimal Salt Medium and crude oil as the carbon source. Taxonomic identification of the endophytic fungi that showed bioactivity in the qualitative test was carried out by analysis of the ITS gene of the region 18S of the rDNA. Endophytes showed the best results in the previous qualitative test where selected for a quantitative in vitro test for 30 days. Residual hydrocarbons were tracked by infrared spectroscopy (IR) and gas chromatography (GC) with a flame ionization detector. The maximum removal rates of total petroleum hydrocarbons were 99.6% (IR) and 99.8% (GC), corresponding to fungi of the genus Verticillium sp. and Xylaria sp. 1 respectively. This is the first report of biodegradation of crude oil hydrocarbons by endophytic fungi in a tropical ecosystem. The results suggest these fungal isolates are potential hydrocarbon biodegraders that could be used in bioremediation processes.