Bbreviated as (CP/C), revealed the differential expression of 329 genes between the two biofilms (see Tables two, S4 and S5). Comparison of gene expression upon selfcolonization (CC/C experiment) and upon pathogen colonization (CP/C experiment) showed a prevalent genetic response to entry of exogenous bacteria into commensal MG1655 F9 biofilm, with all the exact same 89 overexpressed and 26 repressed genes in each circumstances (see Tables S4 and S5). In addition, comparison of nonself versus selfcolonized analyses (CP/CC comparison) indicated significant certain differential gene expression in response to 55989a colonization, with 61 repressed genes and 108 overexpressed genes. The distribution of these 169 genes in the diverse COG functional classes is comparable to that discovered in CP/C transcription profile analysis, including 30 to 40 of poorly characterized genes (Tables two, S4 and S5). Additionally, a number of overexpressed and underexpressed genes overlapped CP/C and CP/CC evaluation, (Table S1), suggesting that these genes may very well be involved in precise responses to colonization of E. coli commensal biofilm by pathogenic bacteria.3-(Hydroxymethyl)piperidin-2-one Formula Colonization responses of commensal biofilm bacteria minimize pathogen colonizationAlthough our analysis focused on E. coli MG1655 genes, most of these genes are also present on the E. coli 55989 genome and we could not rule out that the observed variation in transcription also reflected responses induced inside the 55989a pathogen. We nevertheless hypothesized that the identified genetic responses could contribute to limiting pathogen colonization within MG1655 F9 commensal biofilm. To test this, we chosen 22 genes differentially expressed by MG1655 F9 biofilm bacteria upon colonization by 55989a, by comparing the CP/C and CP/CC versus CC/C datasets.213125-87-2 Chemscene These 22 genes incorporated genes coding for membrane and envelope proteins (36 ), proteins of phage origin (27 ), regulators implicated in biofilmassociated phenotype (13 ) and genes of unknown function (14 ), (Table 3 and Fig.PMID:33395145 S1). RTPCR experiments on six of the most regularly expressed of these 22 genes (hokD, kduI, ylcE, yceP, yliH and yciF) indicated that, while ratios obtained using the two approaches differed, all tested genes displayed enhanced levels of transcription inside mixed CP biofilm in comparison to mixed CC biofilm (information not shown). We then performed nonpolar deletion on the 22 selected genes in commensal strain MG1655 F9. Together with the exception of yaeT (bamA), all mutants exhibited wildtype development and biofilm formation capability (data not shown). Biofilms corresponding to the 21 remaining mutants were inoculated with wildtype 55989a employing the process described in Fig. 1A. Determination on the percentage of pathogens in resulting mixed CP biofilms showed that biofilms formed by MG1655 F9 mutants yliE, ypjC, rcsA, stfE and yiaF mutant have been colonized by the pathogen 55989a at considerably greater levels than the wildtype strain (p,0.01) (Fig. 1B). yliE encodes a conserved inner membrane hypothetical protein of 90 kDa that consists of an EAL domain characteristic of phosphodiesterase enzymes degrading cdiGMP and normally involved in transition among person and community lifestyles [36]; ypjC encodes a hypothetical protein of 18 kDa; rcsA codes forPathogen colonization of commensal biofilm triggers particular genetic responsesTo investigate the genetic response of MG1655 F9 biofilm bacteria upon introduction of E. coli 55989a, we first compared the expression profile of monospecific.