Dataset Information

Community behavior and spatial regulation within a bacterial microcolony in deep tissue sites serves to protect against host attack.

ABSTRACT: Bacterial pathogens express virulence-specific transcriptional programs that allow tissue colonization. Although phenotypic variation has been noted in the context of antibiotic exposure, no direct evidence exists for heterogeneity in virulence-specific transcriptional programs within tissues. In a mouse model of Yersinia pseudotuberculosis infection, we show that at least three subpopulations of bacteria develop within a single tissue site in response to distinct host signals. Bacteria growing on the exterior of spleen microcolonies responded to soluble signals and induced the nitric oxide (NO)-detoxifying gene, hmp. Hmp effectively eliminated NO diffusion and protected the interior bacterial population from exposure to NO-derived inducing signals. A third subpopulation, constituting the most peripherally localized bacteria, directly contacted neutrophils and transcriptionally upregulated a virulence factor. These studies demonstrate that growth within tissues results in transcriptional specialization within a single focus of microbial replication, facilitating directed pathogen counterattack against the host response.

SUBMITTER: Davis KM

PROVIDER: S-EPMC4669952 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Community behavior and spatial regulation within a bacterial microcolony in deep tissue sites serves to protect against host attack.

Davis Kimberly M KM Mohammadi Sina S Isberg Ralph R RR

Cell host & microbe 20141211 1

Bacterial pathogens express virulence-specific transcriptional programs that allow tissue colonization. Although phenotypic variation has been noted in the context of antibiotic exposure, no direct evidence exists for heterogeneity in virulence-specific transcriptional programs within tissues. In a mouse model of Yersinia pseudotuberculosis infection, we show that at least three subpopulations of bacteria develop within a single tissue site in response to distinct host signals. Bacteria growing ...[more]

PMID: 25500192

Similar Datasets

Project description:The aggregation behavior of two cationic surfactants, i.e., cetyldimethylethanolammonium bromide (CDMEAB) and cetyltributylphosphonium bromide (CTBPB), within an aqueous deep eutectic solvent (DES) is studied. The synthesized DES is composed of 1:2 mole ratio of choline chloride and glycerol and is further characterized by Fourier transform infrared (FTIR) and 1H NMR spectroscopy techniques. The critical micellar concentration (CMC), micellar size, and intermolecular interaction in surfactants within Gly-based DES solutions are investigated by various techniques including surface tension, conductivity, fluorescence, dynamic light scattering (DLS), FTIR, 1H NMR, and two-dimensional (2D) nuclear Overhauser effect spectroscopy (NOESY). The various interfacial properties and thermodynamic parameters are determined in the presence of 5 wt % glyceline (Gly)-based DES in an aqueous solution. The CMC, aggregation number (N agg), and Stern-Volmer constant (K sv) have also been determined by a steady-state fluorescence method. DLS is used to obtain information regarding the size of the aggregates formed by the cationic surfactants in DES solutions. FTIR spectroscopy is used to study the surfactant-DES interactions that tune the micellar structure of the surfactants within the Gly-based DES solution. The functional groups involved in the interactions (H-bonding and electrostatic) are the head groups (HO-CH2-CH2-N+ ion for CDMEAB and quaternary phosphonium (P+) ion for CTBPB) of the surfactants with the -OH-containing Gly DES. The hydrophobic moieties are involved in the hydrophobic interactions. The 1H NMR data show that differences in chemical shifts can provide significant information about the interactions taking place within the system. 1H NMR and NOESY techniques are further employed to strengthen our claim on the feasible structural arrangements within the aqueous surfactant-DES self-assembled structures. It is observed that both the cationic surfactants, i.e., CDMEAB and CTBPB, form self-assembled nanostructures in the Gly-based DES solutions. The present results are expected to be useful for colloidal solutions of DES and their mixtures with water.

Project description:BackgroundThe chlamydial developmental cycle involves the alternation between the metabolically inert elementary body (EB) and the replicating reticulate body (RB). The triggers that mediate the interchange between these particle types are unknown and yet this is crucial for understanding basic Chlamydia biology.Presentation of the hypothesisWe have proposed a hypothesis to explain key chlamydial developmental events whereby RBs are replicating strictly whilst in contact with the host cell membrane-derived inclusion via type three secretion (T3S) injectisomes. As the inclusion expands, the contact between each RB and the inclusion membrane decreases, eventually reaching a threshold, beyond which T3S is inactivated upon detachment and this is the signal for RB-to-EB differentiation.Testing the hypothesisWe explore this hypothesis through the development of a detailed mathematical model. The model uses knowledge and data of the biological system wherever available and simulates the chlamydial developmental cycle under the assumptions of the hypothesis in order to predict various outcomes and implications under a number of scenarios.Implications of the hypothesisWe show that the concept of in vitro persistent infection is not only consistent with the hypothesis but in fact an implication of it. We show that increasing the RB radius, and/or the maximum length of T3S needles mediating contact between RBs and the inclusion membrane, and/or the number of inclusions per infected cell, will contribute to the development of persistent infection. The RB radius is the most important determinant of whether persistent infection would ensue, and subsequently, the magnitude of the EB yield. We determine relationships between the length of the T3S needle and the RB radius within an inclusion, and between the RB radius and the number of inclusions per host cell to predict whether persistent infection or normal development would occur within a host cell. These results are all testable experimentally and could lead to significantly greater understanding of one of the most crucial steps in chlamydial development.

Dataset Information

Community behavior and spatial regulation within a bacterial microcolony in deep tissue sites serves to protect against host attack.

Publications

Community behavior and spatial regulation within a bacterial microcolony in deep tissue sites serves to protect against host attack.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets