Navegando por Autor "Brito, Cássia de Fátima Pereira de"

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    Identificação molecular, caracterização bioquímica e prospecção de metabólitos secundários produzidos por Photorhabdus sp.
    (Universidade Estadual do Norte do Paraná, 2021) Brito, Cássia de Fátima Pereira de; Alves, Viviane Sandra; https://orcid.org/0000-0003-2381-8115; http://lattes.cnpq.br/3794580975938452; Alves, Viviane Sandra; https://orcid.org/0000-0003-2381-8115; http://lattes.cnpq.br/3794580975938452; Lescano, Luis Eduardo Azevedo Marques; https://orcid.org/0000-0003-0874-9211; http://lattes.cnpq.br/0477576296995064; Ferreira, Dhiego Gomes; https://orcid.org/0000-0003-4375-6556; http://lattes.cnpq.br/7326714947358202
    This study aimed to identify the symbiont bacteria of four isolates of entomopathogenic nematodes (NEPs) of the genus Heterorhabditis sp. (isolates UENP-n 04, 05, 06 and UEL 08), native to Northern Paraná, and to perform the molecular, biochemical and biological characterization of these bacteria, besides prospecting the production capacity of secondary metabolites with antimicrobial, fungicidal and insecticidal effects. The bacteria were isolated from the hemolymph of larvae of Galleria mellonella L. (Lepidoptera: Pyralidae) and molecular identification was done by amplification of part of the 16S rRNA gene. It was also characterized by biochemical tests for motility, Gram staining, lipase, protease, lecithinase and bioluminescence activity and evaluated the production of antimicrobial compounds against the bacteria Bacillus thuringiensis, Staphylococcus aureus and Escherichia coli. The pathogenicity on insects was evaluated on caterpillars of G. mellonella, Anticarsia gemmatalis (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) and the fungicidal effect on the fungi Metarhizium anisopliae and Beauveria bassiana. Furthermore, the production of secondary metabolites from extracts was prospected and evaluated for their insecticidal effect on G. mellonella (oral application and via hemolymph), antimicrobial effect on S. aureus, E. coli, and B. thuringiensis bacteria, and fungicidal effect on M. anisopliae and B. bassiana fungi. Three bacterial strains obtained were identified as belonging to the species Photorhabdus luminescens (P05, P06 and L08) and the other as Photorhabdus asymbiotica (P04). As for the biochemical tests, all strains were positive for motility, lipase and protease activity, and bromothymol blue uptake, but negative for lecithinase activity. When inoculated into the hemolymph of G. mellonella, S. frugiperda and A. gemmatalis larvae as suspension, the strains were highly virulent, causing mortality above 85% in all three caterpillar species. When evaluated at different concentrations, P04 proved to be more aggressive, killing over 95% of the infected caterpillars in all concentrations evaluated after 18 hours of inoculation. Regarding the antimicrobial effect, it was observed that the four bacterial strains showed positive activity inhibiting the growth of B. thuringiensis and S. aureus, but only P04 showed antimicrobial effect against E. coli. The effect of the aqueous extracts obtained from the bacterial cultures P04 showed positive results for fungicidal action on B. bassiana and M. anisopliae and the extract from the L08 strain showed antimicrobial effect on S. aureus bacteria, but showed no insecticidal effect on G. mellonella when inoculated in the hemolymph or when ingested.