Detection of ureolytic activity of bacterial strains isolated from entomopathogenic nematodes using infrared spectroscopy

Abstract

The pathogenicity of entomopathogenic nematodes (EPNs) depends directly on the presence of bacteria in the nematode digestive tracts. Based on 16S rRNA and MALDI-TOF analyses 20 isolated bacteria were assigned to 10 species with 10 isolates classified as Pseudomonas ssp. Six strains (30%) show ureolytic activity on Christensen medium. Spectroscopic analysis of the strains showed that the ureolytic activity is strongly correlated with the following wavenumbers: 935 cm(-1) in window W4, which carries information about the bacterial cell wall construction and 1158 cm(-1) in window W3 which corresponds to proteins in bacterial cell. A logistic regression model designed on the basis of the selected wavenumbers differentiates ureolytic from non-ureolytic bacterial strains with an accuracy of 100%. Spectroscopic studies and mathematical analyses made it possible to differentiate EPN-associated Pseudomonas sp. strains from clinical Pseudomonas aeruginosa PAO1. These results suggest, that infrared spectra of EPN-associated Pseudomonas sp. strains may reflect its adaptation to the host.

Comparison of Biological Activity of Field Isolates of Steinernema feltiae with a Commercial S. feltiae Biopesticide Product

“…and Photorhabdus (in Heterorhabditis spp. ), e.g., X. bovienii Akhurst, 1983, and P. luminescens Thomas et Poinar, 1979 [ 22 ], although it has been proven that these nematodes also form relationships with other symbiotic bacterial species [ 23 , 24 ]. The efficacy and biocontrol success of EPN can be enhanced through improved understanding of their biology and ecology.…”

“…The efficacy and biocontrol success of EPN can be enhanced through improved understanding of their biology and ecology. Many endogenous (microbiome) and environmental factors influence the survival of EPN and their transmission to the target species following their application as a biocontrol agent [ 23 , 25 ].…”

Impact of Abiotic and Biotic Environmental Conditions on the Development and Infectivity of Entomopathogenic Nematodes in Agricultural Soils

“…Research on the nematode–bacterium system indicates that, in addition to the main EPN bacterial endosymbionts ( Xenorhabdus and Photorhabdus ), there is a frequently associated microbiota (FAM) consisting of several members of the Proteobacteria phylum. The endosymbionts and the accompanying microbiota determine the pathobiome of EPNs [ 77 , 78 , 79 ].…”