Author: GABRIELA PATRICIA HEREDIA ABARCA
Los hongos Beltraniella japonica, B. portoricensis, Beltraniopsis sp., Gliomastix murorum y MR45 asociados a hojarasca, se cultivaron en dos medios líquidos, Czapeck–Dox–extracto de levadura (CDL) y caldo de papa dextrosa (CPD). En cada caso, el micelio se separó del filtrado y ambas fases se sometieron a maceración con AcOEt obteniendo los correspondientes extractos fúngicos de filtrado (EFF) y micelio (EFM). Éstos se evaluaron en los ensayos de reducción del radical 2,2–difenil–1 –picrilhidrazilo (DPPH) y el antimicrobiano por microdilución contra cuatro patógenos. Los resultados mostraron una alta capacidad antioxidante en los EFF de B. japonica, G. murorum y MR45, en los medios CPD y CDL. La actividad antimicrobiana más alta se detectó contra S. aureus, producido por las dos cepas de Beltraniella (200 µg) en CPD y contra E. carotovora en el EFM de B. japonica en CDL. En ambos medios, B. japonica produce meleína, no obstante, para las demás cepas activas no se identificaron los componentes. El perfil biológico y las exploraciones preliminares por cromatografía de gases – espectrometría de masas (CG–EM) de los extractos activos confirman la versatilidad metabólica de los hongos del trópico mexicano, los cuales pueden ser susceptibles de manipulación para la producción de metabolitos útiles en farmacia y agricultura.
Martín Antonio Pablo Moreno Pérez MARIA MARCELA GAMBOA ANGULO GABRIELA PATRICIA HEREDIA ABARCA Blondy Beatriz Canto Canché MIGUEL ENRIQUE ROSADO VALLADO Irma Leticia Medina Baizabal RAUL TAPIA TUSSELL (2014)
In the search for natural alternatives to control fungal diseases, antagonistic fungi are valuable sources to find new models. In the present study, a total of 41 tropical micromycetes were isolated from plant debris submerged in sinkholes of the Yucatán Península. All strains were tested in antagonist assays against four phytopathogenic fungi (Colletotrichum gloeosporioides, Corynespora cassiicola, Curvularia sp. and Fusarium sp.). Results of the antagonistic assays showed mycelial growth inhibition (MCI ≥50 %) by 17 isolates (41 %) against at least one of the targets tested. The highest inhibition was exhibited by the Hypocrea lixii OSN-37 (MCI=61-77%) and Rhizoctonia solani OSE-73 (MCI=55-64%) strains against all targets while Pestalotiopsis mangiferae OH-02 (51-59%) caused inhibition on three of four pathogen strains. These three strains were cultured in fermented rice to obtain their ethyl acetate and methanol extracts which were tested against C. gloeosporioides using the microdilution assay. Results showed H. lixii OSN-37 and R. solani OSE-73 to be producers of antifungal metabolites as one of their modes of action. In conclusion, three promising antagonistic native strains were isolated from plant debris submerged in the Yucatán sinkholes, representing a valuable contribution to the development of ecofriendly alternatives to control fungal diseases in agriculture crops of the tropical regions.
MARIA MANUELA DE JESUS REYES ESTEBANEZ ELIZABETH DE LOS ANGELES HERRERA PARRA JARIO CRISTOBAL ALEJO GABRIELA PATRICIA HEREDIA ABARCA BLONDY BEATRIZ CANTO CANCHE Irma Leticia Medina Baizabal MARIA MARCELA GAMBOA ANGULO (2011)
Forty seven fungal strains were isolated from plant debris in the tropical regions of Mexico, where fifteen of them were identified to species and twenty two to genus level. All isolates were grown in fermented rice and their EtOAc extracts screened against ten targets, four bacteria (Bacillus subtilis, Erwinia carotovora, Staphylococcus aureus and Xanthomonas campestris), the yeast Candida albicans, three phytopathogenic fungi (Alternaria tagetica, Colletotrichum gloeosporioides and Fusarium oxysporum), the Oomycete Pythium aphanidermatum and the nematode Meloidogyne incognita. Antimicrobial activity was detected in 18 isolates against at least one of the target strains tested. Seven of these isolates with broad spectrum activity, which were defatted and their minimum inhibitory concentrations (MICs) were determined by microdilution assay. The greatest antagonistic action was produced by Cylindrium elongatum with broad spectrum activity while Corynespora cassiicola and Memnoniella sp. MR33 showed moderate antimicrobial properties. On other hand, in vitro nematotoxic activity was clearly detected only in Selenosporella sp. GH26 with 91 (LD 50) and 147 µg/ml (LD 90). This is the first report on the isolation and biological evaluation of anamorphic fungi from some Mexican tropical regions, demonstrating their potential as a source of biologically active natural metabolites for use in future applications in agriculture or pharmacy. Antimicrobial and nematicidal screening of anamorphic fungi isolated from plant debris of tropical areas in Mexico
MARTIN PABLO ANTONIO MORENO PEREZ MARIA MARCELA GAMBOA ANGULO GABRIELA PATRICIA HEREDIA ABARCA BLONDY BEATRIZ CANTO CANCHE CECILIA MONICA RODRIGUEZ GARCIA Irma Leticia Medina Baizabal LETICIA PERAZA ECHEVERRIA (2016)
Nowadays, it is highly necessary to find more and safer agrochemicals. In this sense, micromycetes are an important source of natural products which could be used to control plant diseases. Therefore with the aims to contribute in this searching of natural products with antimicrobial applications, a total of 49 fungal strains were isolated from the Yucatan Peninsula. These fungi were cultured in fermented rice, their respective organic extracts macerated in ethyl acetate (EAE) and methanol (ME) were obtained and tested against five fungal pathogens of agricultural importance. These included Alternaria chrysanthemi, Colletotrichum gloeosporioides, Mycosphaerella fijiensis, and the bacteria Erwinia carotovora and Xanthomonas campestris using microdilution assays. The 69% of fungal extracts showed antifungal or antibacterial (2000 and 200 µg/mL, respectively) against at least one of the tested target. Strains Penicillium sp. OSE-61, Fusarium sp. OH2-30, Hypocrea lixii OSN-37 and Rhizoctonia solani OSE-73 showed activity against at least three of the five study pathogens. The most active EAE were partitioned, and its low (A), medium (B) polarity and precipitated (C) were obtained and assessed. The fraction A from Fusarium KS-15 displayed the lowest Minimum Inhibitory Concentration (MIC ≤25 µg/mL) and bactericide effect on X. campestris; fraction B of Penicillium sp. OSE-61 was relatively greater than the previous on A. chrysanthemi (MIC ≤500 µg/mL). Last fraction also exhibited good inhibitory effect on C. gloeosporioides. Finally, fraction B of H. lixii OSN-37 displayed promissory antifungal effect on C. gloeosporioides y M. fijiensis (MIC=1000 µg/mL). This research contributes to enrich the limited knowledge on the biological activity of native anamorphic fungi of the sinkholes of Yucatan and its potential use in biotechnological applications in agriculture.
Culture filtrates and mycelia extracts (methanol and ethyl acetate) from nine selected Mexican tropical fungal strains were tested against second stage juveniles (J2) of Meloidogyne incognita, in vitro conditions. The micromycetes Acremonium kiliense TA31, Aspergillus sp. 2XA5, Gliocladium sp. MR41, Selenosporella sp. MR26, Stagonospora sp. TA34, and four unidentified strains (TA13, 2TA6, 2TA7, and 2XA7) were cultured on Czapeck-Dox medium for 14 days and mycelial mat was separated by filtration for metabolites extraction. Aspergillus sp. 2XA5 and Selenosporella sp. MR26 showed the highest nematotoxic activity both in culture filtrates (100 % mortality) and methanol extracts (> 90 % mortality). The lowest EC50 (0.08 mg mL-1) was exhibited by the methanol extract of the unidentified strain 2XA7. The results obtained indicate that tropical mycobiota have potential as biological control agents of plant parasitic nematodes.
ANA LILIA RUIZ JIMENEZ AZUCENA GONZALEZ-COLOMA MARIA FE ANDRES ESAU RUIZ SANCHEZ GABRIELA PATRICIA HEREDIA ABARCA SERGIO RUBEN PERAZA SANCHEZ Irma Leticia Medina Baizabal MARIA MANUELA DE JESUS REYES ESTEBANEZ Blondy Beatriz Canto Canché MARIA MARCELA GAMBOA ANGULO (2017)
Fungal metabolites are promising alternatives for the development of biorational pesticides. In this sense, microfungi from tropical regions are valuable sources of natural compounds for pest management. With the aim of broadening the search for new eco-friendly products to manage plant pests, this study was carried out to evaluate the biological activity of 23 tropical fungal extracts on three species of phytophagous insects and a plant parasitic nematode. In addition, the active principles of the most effective extract were identified. The insect deterrent activity of fungal extracts was evaluated on the settling of aphids Myzus persicae and Rhopalosiphum padi, and on the feeding of lepidoptera larva Spodoptera littoralis; the nematostatic activity was evaluated on the mobility of Meloidogyne javanica. Active metabolites from Gliomastix masseei were identified by GC-MS techniques and by comparison with commercial standards. Results showed seven extracts with strong effect on the settling of M. persicae and R. padi (settling inhibition >80%). The calculated median of effective concentration (EC50) values ranged from 8 to 38μg/cm2 for the extracts of Clonostachys rosea and G. masseei, respectively. Bioassay-guided separation of the ethyl acetate extract of G. masseei revealed the presence of fatty acids and their derivatives, where methyl 9-octadecenoate was the most active compound with EC50 values of 16μg and 35μg/cm2 for M. persicae and R. padi, respectively. Extracts of C. rosea and G. masseei could be a promising option in the control of pest aphids in agriculture.