Navegando por Autor "Abreu, Lucas M."
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Item Fusarium udum revisited: a common, but poorly understood member of the Fusarium fujikuroi species complex(Mycological Progress, 2019-02) Abreu, Lucas M.; Pfenning, Ludwig H.; Melo, Maruzanete Pereira de; Costa, Marileide Moreira; Reis, Ailton; Cabral, Cleia Santos; Lima, Cristiano S.Fusarium udum is the causal agent of a wilt disease on pigeon pea (Cajanus cajan) in tropical regions. This species shares morphological characteristics with F. oxysporum, leading to misidentification when the diagnosis is solely based on morphological markers. The sexual stage of this fungus was observed on stems of Cajanus in India and was formally described as Gibberella indica. In Brazil, a wilt disease is reported on Crotalaria, but the etiological agent has not been identified correctly so far. In this study, we tested the hypothesis that the causal agent of a wilt on Crotalaria belongs to the same species pathogenic to C. cajan. Strains obtained from diseased Crotalaria spp. were characterized through molecular phylogeny of TEF, TUB and RPB2, laboratory crosses, morphological markers, and pathogenicity tests. Strains from Crotalaria from Brazil formed a well-supported clade with F. udum strains from Crotalaria and Cajanus from other countries. Strains from Brazil intercrossed among themselves and also with others from all geographic regions, and formed fertile perithecia, defining a distinct mating population inside the Fusarium fujikuroi species complex. One strain obtained from Cajanus cajan in India is indicated as epitype, and female-fertile tester strains of both mating types were selected for the identification of field isolates through sexual crosses. These results confirm that the species associated with wilt disease on Crotalaria and Cajanus is F. udum. Wilt symptoms caused by F. udum in Cr. ochroleuca are described and illustrated.Item Lactone derivatives produced by a Phaeoacremonium sp., an endophytic fungus from Senna spectabilis(Journal of Natural Products, 2017-04-20) Silva, Geraldo H.; Zeraik, Maria L.; Oliveira, Camila M. de; Teles, Helder L.; Trevisan, Henrique C.; Pfenning, Ludwig H.; Nicolli, Camila P.; Young, Maria C. M.; Mascarenhas, Yvonne P.; Abreu, Lucas M.; Saraiva, Amanda C.; Medeiros, Alexandra I.; Bolzani, Vanderlan da S.; Araujo, Angela R.Three new isoaigialones, A, B, and C (1–3), along with aigialone (4), were isolated from the crude EtOAc extract of a Phaeoacremonium sp., an endophytic fungus obtained from the leaves of Senna spectabilis. The structures of these compounds were elucidated based on the analysis of spectroscopic data. Compounds 2 and 4 were active against the phytopathogenic fungi Cladosporium cladosporioides and C. sphaerospermum. This is the first report of metabolites produced by an Phaeoacremonium sp., associated with S. spectabilis.Item Larvicidal Activity of Beauveria bassiana extracts against Aedes aegypti and identification of beauvericins(Journal of the Brazilian Chemical Society, 2017-06) Abreu, Lucas M.; Daniel, Juliana F. S.; Silva, Andressa A.; Nakagawa, Danielle H.; Medeiros, Lívia S. de; Carvalho, Mário G.; Tavares, Lucineli J.; Rodrigues-Filho, EdsonBeauveria bassiana is an entomopathogenic fungus that has been well known for its capacity to act as biopesticide on various disease vectors. The analysis of organic extracts of strains CG71 and UNI40 led to identification of cyclodepsipeptides beauvericin, beauvericin A or F, beauvericin E and bassianolide by ultra-high pressure liquid chromatography-high resolution mass spectrometry in tandem mode (UHPLC-HRMS/MS). The larvicidal activity on 3rd instar of Aedes aegypti revealed LC50 0.9887 and 0.4653 ppm in 24 and 48 hours (CG71 methanolic extract), LC50 0.7834 ppm in 48 hours (CG71 ethyl acetate), LC50 0.7834 and 1.8149 ppm (UNI 40 for ethyl acetate and methanolic extracts, respectively) in 48 hours. These findings highlight the potential of B. bassiana metabolites for controlling the vector of Dengue and Zika diseases.Item Multilocus phylogeny of Clonostachys subgenus Bionectria from Brazil and description of Clonostachys chloroleuca sp. nov.(Mycological Progress, 2016-10) Abreu, Lucas M.; Moreira, Gláucia M.; Carvalho, Vívian G.; Schroers, Hans-Josef; Pfenning, Ludwig H.Phylogenetic analyses based on protein-encoding gene exons and introns of ATP citrate lyase (ACL1), beta tubulin (TUB), the largest subunit of RNA polymerase II (RPB1), and translation elongation factor 1-α (TEF1) are used for inferring the existence of a new Clonostachys species from the Cerrado biome in Brazil, described here as C. chloroleuca. The species produces dimorphic, primary, and secondary conidiophores that form consistently greenish conidial masses on artificial media. It resembles therefore C. rosea f. catenulata although it differs from this species by less adpressed branches in the secondary conidiophores. The new species is also phylogenetically related to C. byssicola and C. rhizophaga. Our inventory suggests that C. byssicola, C. chloroleuca, C. pseudochroleuca, C. rhizophaga, C. rogersoniana, and C. rosea commonly occur in native and agriculturally used soils of the Cerrado and Amazon Forest. Using sequences available from two genome-sequenced strains employed as biological control agents, we confirm the identity of the European strain IK726 as C. rosea and identify strain 67-1 from China as C. chloroleuca.