RESUMO
The relationships between six bacterial symbionts of the entomopathogenic nematodes Heterorhabditis bacteriophora and Heterorhabditis megidis from Poland to species and subspecies of the genus Photorhabdus were evaluated. This study was based on phylogenetic analysis of sequence data of five genes: 16S rRNA, gyrB, recA, gltX, and dnaN. The bacteria were also characterized phenotypically by biochemical and physiological tests. Our results have revealed that the Photorhabdus strains isolated from H. megidis belong to P. temperata, subsp. temperata and subsp. cinerea. Isolates from H. bacteriophora represent P. luminescens subs. kayaii and P. temperata subs. cinerea. This study for the first time provides evidence for H. bacteriophora and P. temperata subsp. cinerea symbiotic association. In addition, we tested whether the microsymbionts of the Polish H. bacteriophora and H. megidis isolates support the development of non-native nematode host population and colonization of their infective juveniles. It has been shown that the studied Photorhabdus strains can readily swap their nematode host, both at intra- and interspecies level. It supports the hypothesis of different symbiotic associations in the Heterorhabditis-Photorhabdus lineage.
Assuntos
Photorhabdus , Rhabditoidea/microbiologia , Animais , Proteínas de Bactérias/genética , DNA Girase/genética , DNA Bacteriano/genética , DNA Polimerase Dirigida por DNA/genética , Genes Essenciais/genética , Tipagem de Sequências Multilocus , Fenótipo , Photorhabdus/classificação , Photorhabdus/genética , Photorhabdus/isolamento & purificação , Filogenia , Polônia , RNA Ribossômico 16S/genética , Recombinases Rec A/genética , Análise de Sequência de DNA , SimbioseRESUMO
Steinernema silvaticum is a common entomopathogenic nematode in soil of Europe; however, little is known about the bacteria living in symbiosis with this animal. In this study, we have isolated four bacterial strains from S. silvaticum and identified them as members of the species Xenorhabdus bovienii. This study was based on 16S rRNA and concatenated recA, dnaN, gltX, and gyrB gene sequence analysis. In addition, phenotypic traits have been considered, indicating that the tested strains are the most similar to those of X. bovienii. The phylogenetic relationships between the isolated strains and other strains of X. bovienii derived from various nematode hosts were analyzed and discussed. This is the first report confirming the symbiotic association of X. bovienii with S. silvaticum.
Assuntos
Rabditídios/metabolismo , Rabditídios/microbiologia , Solo/parasitologia , Simbiose/fisiologia , Xenorhabdus/metabolismo , Animais , Proteínas de Bactérias/genética , DNA Girase/genética , DNA Polimerase Dirigida por DNA/genética , Europa (Continente) , Fenótipo , Filogenia , RNA Ribossômico 16S/genética , Recombinases Rec A/genética , Xenorhabdus/genéticaRESUMO
The objective of the presented study was to investigate the adsorption of Cu, Co, Mn, Zn, Cd and Mn on A-type zeolite. The isotherms for adsorption of metals from their nitrates were registered. The following adsorption constants K of metals were found: 162,890, 124,260, 69,025, 16,035, 10,254, and 151 [M(-1)] for Cu, Co, Mn, Zn, Cd, and Ni, respectively, for the concentration range 10(-4)-10(-3) M. On the other hand, the investigation of pH influence on the distribution constants of metals showed that the adsorption of metals proceeds essentially through an ion-exchange process, surface hydrolysis, and surface complexation. The supplementary results from DRIFT, scanning electron microscopy, and X-ray diffraction methods confirmed the presumption about the possible connection between the electronic structure of divalent ions and their adsorption behavior, showing that ions with d5 and d10 configurations such as Mn2+, Zn2+, Cd2+, with much weaker hydrolytic properties than Cu2+ and Ni2+, strongly interact with the zeolite framework and therefore their affinity to the zeolite phase is much stronger when compared with that of the Ni2+ ion, but at the same time not as strong as the affinity of the Cu2+ ion, the latter forming a new phase during the interaction with zeolite framework. For Zn2+, during inspection of the correlation between the proton concentration H/Al and zinc concentration Zn/Al on the zeolite surface, the formation of the surface complex [triple bond]S-OZn(OH) was proposed. A correlation between the heterogeneity of proton concentrations H/Al on Me-zeolite surfaces and the hydrolysis constants pKh of Me2+ ions was found.
