Division of Labor during Biofilm Matrix Production

Organisms as simple as bacteria can engage in complex collective actions, such as group motility and fruiting body formation. Some of these actions involve a division of labor, where phenotypically specialized clonal subpopulations or genetically distinct lineages cooperate with each other by performing complementary tasks. Here, we combine experimental and computational approaches to investigate potential benefits arising from division of labor during biofilm matrix production. We show that both phenotypic and genetic strategies for a division of labor can promote collective biofilm formation in the soil bacterium Bacillus subtilis. In this species, biofilm matrix consists of two major components, exopolysaccharides (EPSs) and TasA. We observed that clonal groups of B. subtilis phenotypically segregate into three subpopulations composed of matrix non-producers, EPS producers, and generalists, which produce both EPSs and TasA. This incomplete phenotypic specialization was outperformed by a genetic division of labor, where two mutants, engineered as specialists, complemented each other by exchanging EPSs and TasA. The relative fitness of the two mutants displayed a negative frequency dependence both in vitro and on plant roots, with strain frequency reaching a stable equilibrium at 30% TasA producers, corresponding exactly to the population composition where group productivity is maximized. Using individual-based modeling, we show that asymmetries in strain ratio can arise due to differences in the relative benefits that matrix compounds generate for the collective and that genetic division of labor can be favored when it breaks metabolic constraints associated with the simultaneous production of two matrix components

Product Generation Module: Automated Production Planning for optimized workload and increased efficiency in Matrix Production Systems

Ever increasing demand for individualized and customized products induce the need for high variability in production and manufacturing through Mass Customisation. Mass Customisation requires more flexibility and adaptability capabilities in production systems. Matrix Production is a tact free job-shop like production system enabling variable production routing through a matrix shaped layout of partially redundant machines. Hence, it is one way to increase a production system’s flexibility and adaptability. A more powerful production control system comes hand in hand with the evolution towards a tact free Matrix Production System. However, the additional degree of freedom due to the flexibility not only touches production control, but also production planning, thus enabling the production of portfolio external products. Implementation of a Product Generation Module optimizes the workload of Matrix Production Systems to increase their efficiency by assessing the suitability of co-production of portfolio external products. Generation of suitable production orders increase machine utilization without impeding the original multi-dimensional production goals. Thus, reaching new production strategies that include the creation of value through effective manipulation of minor products and byproducts. The flexibility of Matrix Production Systems acts as the Product Generation Modules enabler, insofar as flexibility is the ability of a system to perform within an acceptable production corridor without layout and planning adjustments. This can be enhanced by making use of the Matrix Production Systems adaptability to increase the set of portfolio external products through layout and planning adjustments. Hence, this strategy leads to a continuous automated planning phase and additional revenue due to the additional manufacture of minor products within a Matrix Production System. Doing so allows the Matrix Production System to react towards external demand related and internal capacity related events without sacrificing precious value creation opportunities

Autocrine Transforming Growth Factor β Signaling Regulates Extracellular Signal-regulated Kinase 1/2 Phosphorylation via Modulation of Protein Phosphatase 2A Expression in Scleroderma Fibroblasts

BACKGROUND. During scleroderma (SSc) pathogenesis, fibroblasts acquire an activated phenotype characterized by enhanced production of extracellular matrix (ECM) and constitutive activation of several major signaling pathways including extracellular signal-related kinase (ERK1/2). Several studies have addressed the role of ERK1/2 in SSc fibrosis however the mechanism of its prolonged activation in SSc fibroblasts is still unknown. Protein phosphatase 2A (PP2A) is a key serine threonine phosphatase responsible for dephosphorylation of a wide array of signaling molecules. Recently published microarray data from cultured SSc fibroblasts suggests that the catalytic subunit (C-subunit) of PP2A is downregulated in SSc. In this study we examined the role and regulation of PP2A in SSc fibroblasts in the context of ERK1/2 phosphorylation and matrix production. RESULTS. We show for the first time that PP2A mRNA and protein expression are significantly reduced in SSc fibroblasts and correlate with an increase in ERK1/2 phosphorylation and collagen expression. Furthermore, transforming growth factor β (TGFβ), a major profibrotic cytokine implicated in SSc fibrosis, downregulates PP2A expression in healthy fibroblasts. PP2A-specific small interfering RNA (siRNA) was utilized to confirm the role of PP2A in ERK1/2 dephosphorylation in dermal fibroblasts. Accordingly, blockade of autocrine TGFβ signaling in SSc fibroblasts using soluble recombinant TGFβ receptor II (SRII) restored PP2A levels and decreased ERK1/2 phosphorylation and collagen expression. In addition, we observed that inhibition of ERK1/2 in SSc fibroblasts increased PP2A expression suggesting that ERK1/2 phosphorylation also contributes to maintaining low levels of PP2A, leading to an even further amplification of ERK1/2 phosphorylation. CONCLUSIONS. Taken together, these studies suggest that decreased PP2A levels in SSc is a result of constitutively activated autocrine TGFβ signaling and could contribute to enhanced phosphorylation of ERK1/2 and matrix production in SSc fibroblasts.National Institutes of Health (AR-44883

Role of TRPV4 in Astrocyte Extracellular Matrix Production

Traumatic Brain Injury (TBI) is an alteration of brain pathology following damage of the central nervous system (CNS) by an external force. In the CNS, glial scar formation often occurs following TBI, and astrocytes are widely believed to contribute to this scar formation. While the role of astrocytes in extracellular matrix (ECM) production is known, the exact mechanism(s) for this event remain unclear. One possible method is the activation of transient receptor potential vanilloid 4 (TRPV4). TRPV4 is a channel protein found in the astrocyte membrane which has been shown to generate intracellular calcium ions following mechanical stimulation. Previous research has shown activation of TRPV4 to increase collagen content in chondrocytes. This research compared mouse astrocyte matrix composition following TRPV4 biochemical activation/inactivation through rheological analysis techniques. Sample storage modulus values were shown to significantly increase following TRPV4 activation possibly due to an increase in astrocyte ECM production

The expression pattern of matrix-producing tumor stroma is of prognostic importance in breast cancer

Background: There are several indications that the composition of the tumor stroma can contribute to the malignancy of a tumor. Here we utilized expression data sets to identify metagenes that may serve as surrogate marker for the extent of matrix production and vascularization of a tumor and to characterize prognostic molecular components of the stroma. Methods: TCGA data sets from six cancer forms, two breast cancer microarray sets and one mRNA data set of xenografted tumors were downloaded. Using the mean correlation as distance measure compact clusters with genes representing extracellular matrix production (ECM metagene) and vascularization (endothelial metagene) were defined. Explorative Cox modeling was used to identify prognostic stromal gene sets. Results: Clustering of stromal genes in six cancer data sets resulted in metagenes, each containing three genes, representing matrix production and vascularization. The ECM metagene was associated with poor prognosis in renal clear cell carcinoma and in lung adenocarcinoma but not in other cancers investigated. Explorative Cox modeling using gene pairs identified gene sets that in multivariate models were prognostic in breast cancer. This was validated in two microarray sets. Two notable genes are TCF4 and P4HA3 which were included in the sets associated with positive and negative prognosis, respectively. Data from laser-microdissected tumors, a xenografted tumor data set and from correlation analyses demonstrate the stroma specificity of the genes. Conclusions: It is possible to construct ECM and endothelial metagenes common for several cancer forms. The molecular composition of matrix-producing cells, rather than the extent of matrix production seem to be important for breast cancer prognosis

Quorum Sensing Influences Burkholderia thailandensis Biofilm Development and Matrix Production

Members of the genus Burkholderia are known to be adept at biofilm formation, which presumably assists in the survival of these organisms in the environment and the host. Biofilm formation has been linked to quorum sensing (QS) in several bacterial species. In this study, we characterized Burkholderia thailandensis biofilm development under flow conditions and sought to determine whether QS contributes to this process. B. thailandensis biofilm formation exhibited an unusual pattern: the cells formed small aggregates and then proceeded to produce mature biofilms characterized by “dome” structures filled with biofilm matrix material. We showed that this process was dependent on QS. B. thailandensis has three acyl-homoserine lactone (AHL) QS systems (QS-1, QS-2, and QS-3). An AHL-negative strain produced biofilms consisting of cell aggregates but lacking the matrix-filled dome structures. This phenotype was rescued via exogenous addition of the three AHL signals. Of the three B. thailandensis QS systems, we show that QS-1 is required for proper biofilm development, since a btaR1 mutant, which is defective in QS-1 regulation, forms biofilms without these dome structures. Furthermore, our data show that the wild-type biofilm biomass, as well as the material inside the domes, stains with a fucose-binding lectin. The btaR1 mutant biofilms, however, are negative for fucose staining. This suggests that the QS-1 system regulates the production of a fucose-containing exopolysaccharide in wild-type biofilms. Finally, we present data showing that QS ability during biofilm development produces a biofilm that is resistant to dispersion under stress conditions. IMPORTANCE The saprophyte Burkholderia thailandensis is a close relative of the pathogenic bacterium Burkholderia pseudomallei, the causative agent of melioidosis, which is contracted from its environmental reservoir. Since most bacteria in the environment reside in biofilms, B. thailandensis is an ideal model organism for investigating questions in Burkholderia physiology. In this study, we characterized B. thailandensis biofilm development and sought to determine if quorum sensing (QS) contributes to this process. Our work shows that B. thailandensis produces biofilms with unusual dome structures under flow conditions. Our findings suggest that these dome structures are filled with a QS-regulated, fucose-containing exopolysaccharide that may be involved in the resilience of B. thailandensis biofilms against changes in the nutritional environment

Extracellular Matrix Production by Osteoblasts on Bioactive Substrata in Vitro

Some bone-substitute biomaterials have been classified as bioactive since they allow direct biological bonding to their surface in vivo. Using in vitro techniques, we have re-created the first stages of this biological bonding phenomenon and compared the initial, fibrillar, extracellular matrices produced by migrated primary osteoblast cell populations in contact with both dense and macroporous calcium phosphate substrata, apatite/bioactive glass composite (ABC) and 45S5 bioactive glass (BAG). The first formed fibrils in contact with these materials may be identified as collagen from their morphology as observed by scanning electron microscopy (SEM). However, the organization of this fibrillar material is significantly different on the five bioactive substrata examined. These in vitro findings may not only be related to both the surface morphology and surface chemistry of the substrata, but also correlated with their levels of in vivo bioactivity