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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Tapping the biotechnological potential of insect microbial symbionts: new insecticidal porphyrins

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Author(s):
Canovas Martinez, Ana Flavia ; de Almeida, Luis Gustavo ; Beraldo Moraes, Luiz Alberto ; Consoli, Fernando Luis
Total Authors: 4
Document type: Journal article
Source: BMC Microbiology; v. 17, JUN 27 2017.
Web of Science Citations: 2
Abstract

Background: The demand for sustainable agricultural practices and the limited progress toward newer and safer chemicals for use in pest control maintain the impetus for research and identification of new natural molecules. Natural molecules are preferable to synthetic organic molecules because they are biodegradable, have low toxicity, are often selective and can be applied at low concentrations. Microbes are one source of natural insecticides, and microbial insect symbionts have attracted attention as a source of new bioactive molecules because these microbes are exposed to various selection pressures in their association with insects. Analytical techniques must be used to isolate and characterize new compounds, and sensitive analytical tools such as mass spectrometry and high-resolution chromatography are required to identify the least-abundant molecules. Results: We used classical fermentation techniques combined with tandem mass spectrometry to prospect for insecticidal substances produced by the ant symbiont Streptomyces caniferus. Crude extracts from this bacterium showed low biological activity (less than 10% mortality) against the larval stage of the fall armyworm Spodoptera frugiperda. Because of the complexity of the crude extract, we used fractionation-guided bioassays to investigate if the low toxicity was related to the relative abundance of the active molecule, leading to the isolation of porphyrins as active molecules. Porphyrins are a class of photoactive molecules with a broad range of bioactivity, including insecticidal. The active fraction, containing a mixture of porphyrins, induced up to 100% larval mortality (LD50 = 37. 7 mu g.cm(-2)). Tandem mass-spectrometry analyses provided structural information for two new porphyrin structures. Data on the availability of porphyrins in 67 other crude extracts of ant ectosymbionts were also obtained with ion-monitoring experiments. Conclusions: Insect-associated bacterial symbionts are a rich source of bioactive compounds. Exploring microbial diversity through mass-spectrometry analyses is a useful approach for isolating and identifying new compounds. Our results showed high insecticidal activity of porphyrin compounds. Applications of different experiments in mass spectrometry allowed the characterization of two new porphyrins. (AU)

FAPESP's process: 14/21584-3 - Systemic and multidisciplinary approach to identify new insecticides produced by insect symbionts
Grantee:Ana Flávia Canovas Martinez
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 11/50877-0 - Diversity, ecology and biotechnological potential of the symbiotic bacteriofauna associated with insects
Grantee:Fernando Luis Cônsoli
Support type: BIOTA-FAPESP Program - Thematic Grants