Afterwards, an additional quality check with the Agilent 2100 Bioanalyzer system was performed

Afterwards, an additional quality check with the Agilent 2100 Bioanalyzer system was performed. Transcriptome analysis. be adapted to another environment as we found several differentially expressed genes involved in the cells metabolism, motility, and chemotaxis as well as stress resistance, which are either up- or downregulated in 2 cells. As 2 cells, in contrast to 1 cells, chemotactically responded to different attractants, including plant root exudates, there is evidence for the rhizosphere being an alternative environment for the 2 2 cells. Since is usually biotechnologically used as a bio-insecticide, investigation of a putative conversation of 2 cells with plants is also of great interest Eltanexor for agriculture. IMPORTANCE The biological function and the fate of 2 cells were unclear. Here, we performed comparative transcriptomics of 1 1 and 2 cultures and found several genes, not only those coding for known phenotypic differences of the two cell forms, that are up- or downregulated in 2 cells compared to levels in 1 cells. Our results suggest that when 1 cells convert to 2 cells, they drastically change their way of life. Thus, 2 cells could easily adapt to an alternative environment such as the rhizosphere and live freely, independent of a host, putatively utilizing plant-derived compounds as nutrient sources. Since 2 cells are not able to reassociate with the nematodes, an alternative lifestyle in the rhizosphere would be conceivable. is a Gram-negative, entomopathogenic bacterium belonging to the family (1, 2). The bacteria undergo a dualistic life cycle including mutualistic symbiosis with nematodes and a pathogenic relationship in which they infect and kill insects (1). was first isolated from the gut of nematodes, found in temperate climates. The bacteria exist in two phenotypically different forms, which are designated primary (1) and secondary (2) cells. After prolonged cultivation, a large portion of single 1 cells undergo phenotypic switching and convert into 2 cells, which differ from 1 cells in various phenotypic traits (3) (Table 1). Most predominant is that 2 cells are less bioluminescent than 1 cells, do not produce red pigments, and are unable to live in symbiosis with the nematode partner (4,C7). So far, phenotypic switching of cells has been observed only unidirectionally from the 1 to the 2 2 cell form (1, 3; our unpublished observations). Previously, phenotypic switching of has been referred to as phase variation (8). However, this phenomenon differs from classical bacterial phase variation as both variants are genetically identical (1; our own unpublished observations) and has therefore been termed phenotypic heterogeneity (9). The exact regulatory mechanism behind phenotypic switching and the biological role of 2 cells still remain elusive. As 2 cells are known not to be capable of reassociating with nematodes and support their growth and Eltanexor development (6), it has been assumed that they might be better Rabbit Polyclonal to Patched adapted to a life in soil (10, 11). However, 2 cells have thus far not been isolated from soil. The fact that they are found only after prolonged cultivation of 1 1 cells led to the assumption that this switch occurs as a response to environmental or metabolic stress (12). It was also observed that, after a period of starvation, 2 cells adapted faster to the addition of nutrients and grew faster than 1 cells. Furthermore, proteome analysis exhibited that 2 cells experience an upregulation of several metabolic enzymes (11). According to this observation, major respiratory enzymes and also the transmembrane proton motive force were found Eltanexor to be upregulated in 2 cells, supporting the assumption that this cell variant might be more adapted for a life in soil Eltanexor (11, 13). TABLE 1 Genes corresponding to 1 1.