RESUMEN
Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease characterized by deposits of immune complexes (ICs) in organs and tissues. The expression of FcγRIIA by human platelets, which is their unique receptor for immunoglobulin G antibodies, positions them to ideally respond to circulating ICs. Whereas chronic platelet activation and thrombosis are well-recognized features of human SLE, the exact mechanisms underlying platelet activation in SLE remain unknown. Here, we evaluated the involvement of FcγRIIA in the course of SLE and platelet activation. In patients with SLE, levels of ICs are associated with platelet activation. Because FcγRIIA is absent in mice, and murine platelets do not respond to ICs in any existing mouse model of SLE, we introduced the FcγRIIA (FCGR2A) transgene into the NZB/NZWF1 mouse model of SLE. In mice, FcγRIIA expression by bone marrow cells severely aggravated lupus nephritis and accelerated death. Lupus onset initiated major changes to the platelet transcriptome, both in FcγRIIA-expressing and nonexpressing mice, but enrichment for type I interferon response gene changes was specifically observed in the FcγRIIA mice. Moreover, circulating platelets were degranulated and were found to interact with neutrophils in FcγRIIA-expressing lupus mice. FcγRIIA expression in lupus mice also led to thrombosis in lungs and kidneys. The model recapitulates hallmarks of human SLE and can be used to identify contributions of different cellular lineages in the manifestations of SLE. The study further reveals a role for FcγRIIA in nephritis and in platelet activation in SLE.
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Autoanticuerpos/inmunología , Plaquetas/inmunología , Inmunoglobulina G/inmunología , Nefritis Lúpica/inmunología , Activación Plaquetaria/inmunología , Receptores de IgG/inmunología , Animales , Autoanticuerpos/genética , Plaquetas/patología , Modelos Animales de Enfermedad , Inmunoglobulina G/genética , Nefritis Lúpica/genética , Nefritis Lúpica/patología , Ratones , Ratones Transgénicos , Activación Plaquetaria/genética , Receptores de IgG/genéticaRESUMEN
Adsorption of conditioning films on a solid surface is the first step in the development of biofilms. With the goal of understanding the preliminary adhesion mechanisms of cyanobacteria on photobioreactor (PBR) materials to prevent biofouling, the physical changes occurring on PBR materials were investigated during the initial adhesion and biofilm formation by Anabaena sp. PCC 7120, a cyanobacterium that is genetically modified to produce linalool. Atomic force microscopy (AFM) revealed that the conditioning film deposition was in the form of spike-like structures on all the materials except PVC. The average heights (in the range 9 - 16 nm) of the conditioning films deposited on glass, PMMA, PC and HDPE were 11 to 20 times higher than on PVC at 96 h. The time dependent change in thickness of conditioning films correlated well with Anabaena cell attachment to the PBR materials. The rapid and significant colonization of Anabaena on glass within 48 h was consistent with the increase in thickness of the conditioning film within this time period. Lack of the conditioning film spike structures and no change in thickness of the conditioning films with time on the PVC together with comparatively delayed cell attachment and conditioning-film protein deposition on this material, indicated that the nanoscale spike structures on the other PBR materials may be accelerating the cell attachment process but are not a prerequisite for cell attachment. These results suggest that PVC should be explored further as an antifouling material for photobioreactors. The thickness of the conditioning films on glass measured by a scratch and scan method was in good agreement with the thickness values measured by an adhesive tape method, indicating that both these methods can be used for fast and reliable AFM thickness determination of bacterial conditioning films.
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Anabaena , Incrustaciones Biológicas , Adhesión Bacteriana , Biopelículas , Incrustaciones Biológicas/prevención & control , Microscopía de Fuerza Atómica , Fotobiorreactores , Propiedades de SuperficieRESUMEN
The transcription factor IRF8 (ICSBP) is required for the development and maturation of myeloid cells (dendritic cells, monocytes, macrophages), and for expression of intrinsic anti-microbial function such as antigen capture, processing and presentation to lymphoid cells, and for activation of these cells in response to cytokines and pro-inflammatory stimuli (IFN-γ, IFN-ß, LPS). IRF8 deficiency in humans causes a severe primary immunodeficiency presenting as susceptibility to infections, complete or severe depletion of blood dendritic cells (DC) subsets, depletion of CD14+ and CD16+ monocytes and reduced numbers and impaired activity of NK cells. In genome-wide association studies (GWAS), sequence variants near IRF8 are significant risk factors for multiple chronic inflammatory diseases in humans including inflammatory bowel disease, lupus, rheumatoid arthritis, multiple sclerosis, and several others. Recent studies have cataloged all the genes bound by and transcriptionally activated by IRF8 in myeloid cells, either alone or in combination with other transcription factors (PU.1, IRF1, STAT1) at steady state and in response to pro-inflammatory stimuli. This IRF1/IRF8 regulome comprises immune pathways such as antigen processing and presentation pathways, expression of costimulatory molecules, cytokines and chemokines, response to stimuli such as cytokine receptors, pathogen-associated molecular pattern receptors, TLRs and nucleotide-binding oligomerization domain-like receptor signaling pathways, and small antiviral GTPases. Members of the IRF8/IRF1 regulome are over-represented amongst genes in which mutations cause primary immunodeficiencies, and are specifically enriched at GWAS loci associated with chronic inflammatory diseases in humans. These recent studies highlight a critical role of IRF8 in the activity of several immune cell types for protection against infections, but also in pathological inflammation associated with common human inflammatory conditions.
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Síndromes de Inmunodeficiencia/etiología , Síndromes de Inmunodeficiencia/prevención & control , Inflamación/etiología , Inflamación/prevención & control , Factores Reguladores del Interferón/metabolismo , Linfocitos/inmunología , Células Mieloides/inmunología , Animales , Humanos , Síndromes de Inmunodeficiencia/metabolismo , Inflamación/metabolismo , Factores Reguladores del Interferón/genética , Linfocitos/metabolismo , Mutación , Células Mieloides/metabolismoRESUMEN
Although cyanobacteria are a common group of microorganisms well-suited to utilization in photobioreactors (PBRs), studies of cyanobacteria fouling and its prevention are scarce. Using a cyanobacterium, Anabaena sp. PCC 7120, which had been genetically modified to enhance linalool production, the formation of conditioning films and the effects of these on the physico-chemical surface properties of various PBR materials during initial adhesion and biofilm formation were investigated. The adhesion assay revealed that the overall attachment of Anabaena was substratum dependent and no correlation between the hydrophobicity/roughness of clean material and cell attachment was found. Surface hydrophilicity/hydrophobicity of all the materials changed within 12 h due to formation of conditioning films. ATR-FTIR spectroscopy revealed that the fractional change in protein deposition between 12 to 96 h was consistent with Anabaena cell attachment but polysaccharide deposition was material specific and did not correlate with cell attachment on the PBR materials. Also, the delay in conditioning film proteins on PVC and PTFE indicated that components other than proteins may be responsible for the decrease in contact angles on these surfaces within 12 h. This indicates the important role of the chemical nature of adsorbed conditioning films in determining the initial attachment of Anabaena to PBR materials. The lower rate of attachment of Anabaena on the hydrophilic surfaces (glass and PMMA) between 72 h to 96 h (regime 3) showed that these surfaces could potentially have low fouling characteristics at extended time scales and should be considered for further research.
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Anabaena/crecimiento & desarrollo , Adhesión Bacteriana , Biopelículas/crecimiento & desarrollo , Materiales de Construcción/microbiología , Fotobiorreactores/microbiología , Adsorción , Anabaena/fisiología , Interacciones Hidrofóbicas e Hidrofílicas , Propiedades de SuperficieRESUMEN
Systemic lupus erythematosus (SLE) is characterized by the development of autoantibodies against diverse self-antigens with damage to multiple organs. Immunization with the SLE autoantigen ß2 -glycoprotein I (ß2 GPI) and lipopolysaccharide (LPS), a known trigger of necroptosis, induces a murine model of SLE. We hypothesized that necroptotic cells, like apoptotic cells, provide a "scaffold" of cellular self-antigens, but, unlike apoptotic cells, necroptotic cells do so in a proinflammatory and immunogenic context. We demonstrate that ß2 GPI indeed binds to necroptotic cells and serves as a target for anti-ß2 GPI autoantibodies. We further demonstrate that necroptotic, but not apoptotic, cells promote antigenic presentation of ß2 GPI to CD4 T cells by dendritic cells. Finally, we show that ß2 GPI/LPS-immunized mice deficient in RIPK3 (receptor-interacting serine/threonine-protein kinase 3) or MLKL (mixed lineage kinase domain like), and consequently unable to undergo necroptosis, have reduced SLE autoantibody production and pathology. RIPK3-/- mice had low levels of SLE autoantibodies and no renal pathology, while MLKL-/- mice produced low levels of SLE autoantibodies initially, but later developed levels comparable with wild type (WT) mice and pathology intermediate to that of WT and RIPK3-/- mice. Serum cytokine levels induced by LPS tended to be lower in RIPK3-/- and MLKL-/- mice than in WT mice, suggesting that impaired proinflammatory cytokine production may impact the initiation of autoantibody production in both strains. Our data suggest that self-antigen (i.e. ß2 GPI) presented in the context of necroptosis and proinflammatory signals may be sufficient to overcome immune tolerance and induce SLE.
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Autoantígenos/inmunología , Lupus Eritematoso Sistémico/inmunología , Necroptosis/inmunología , beta 2 Glicoproteína I/metabolismo , Animales , Presentación de Antígeno/inmunología , Células Presentadoras de Antígenos/metabolismo , Apoptosis , Autoanticuerpos/inmunología , Línea Celular , Citocinas/metabolismo , Células Dendríticas/metabolismo , Antígenos de Histocompatibilidad Clase II/metabolismo , Mediadores de Inflamación/metabolismo , Lipopolisacáridos/farmacología , Ratones Endogámicos C57BL , Unión Proteica , Proteínas Quinasas/metabolismo , Proteína Serina-Treonina Quinasas de Interacción con Receptores/metabolismoRESUMEN
Systemic lupus erythematosus (SLE) is a prototypic model for B cell epitope spread in autoimmunity. Autoantibodies to numerous and molecularly distinct self-antigens emerge in a sequential manner over several years, leading to disease manifestations. Among the earliest autoantibodies to appear are those targeting the apoptotic cell-binding protein ß2-glycoprotein I (ß2GPI). Notably, mice immunized with ß2GPI and LPS display a remarkably similar pattern of autoantibody emergence to that seen in human SLE. Here, we used this model to investigate whether epitope spread to SLE-related autoantibodies is associated with a unique or limited ß2GPI-specific T cell response. We ask whether MHC class II haplotype and its associated T cell epitope restriction impact epitope spread to SLE-related autoantibodies. We found that ß2GPI/LPS-immunized mice produced similar SLE-related autoantibody profiles regardless of their ß2GPI T cell epitope specificity or MHC class II haplotype. Although ß2GPI T cell epitope specificity was clearly determined by MHC class II haplotype, a number of different ß2GPI T cell epitopes were associated with epitope spread to SLE-related autoantibodies. Notably, one ß2GPI T cell epitope (peptide 23, NTGFYLNGADSAKCT) was also recognized by T cells from an HLA-DRB1*0403(+) autoimmune patient. These data suggest that the generation of a ß2GPI-reactive T cell response is associated with epitope spread to SLE-related autoantibodies, independent of epitope specificity or MHC class II restriction. On the basis of these findings, we propose that factors enabling a ß2GPI-reactive T cell response may predispose individuals to the development of SLE-related autoantibodies independent of their MHC class II haplotype.
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Autoanticuerpos/inmunología , Epítopos de Linfocito T/inmunología , Lupus Eritematoso Sistémico/inmunología , Linfocitos T/inmunología , beta 2 Glicoproteína I/inmunología , Secuencia de Aminoácidos , Animales , Células Cultivadas , Ensayo de Inmunoadsorción Enzimática , Epítopos de Linfocito T/metabolismo , Femenino , Cadenas HLA-DRB1/genética , Cadenas HLA-DRB1/inmunología , Haplotipos/inmunología , Antígenos de Histocompatibilidad Clase II/genética , Antígenos de Histocompatibilidad Clase II/inmunología , Humanos , Hibridomas , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Linfocitos T/metabolismo , beta 2 Glicoproteína I/metabolismoRESUMEN
Autoimmune diseases result from a break in immune tolerance leading to an attack on self-antigens. Autoantibody levels serve as a predictive tool for the early diagnosis of many autoimmune diseases, including type 1 diabetes. We find that a genetic locus on mouse chromosome 12 influences the affinity maturation of antibodies as well as autoantibody production. Thus, we generated a NOD.H2(k) congenic strain bearing B10 alleles at the locus comprised within the D12Mit184 and D12Mit12 markers, which we named NOD.H2(k)-Chr12. We determined the biological relevance of the Chr12 locus on the autoimmune process using an antigen-specific TCR transgenic autoimmune mouse model. Specifically, the 3A9 TCR transgene, which recognizes a peptide from hen egg lysozyme (HEL) in the context of I-A(k), and the HEL transgene, which is expressed under the rat-insulin promoter (iHEL), were bred into the NOD.H2(k)-Chr12 congenic strain. In the resulting 3A9 TCR:iHEL NOD.H2(k)-Chr12 mice, we observed a significant decrease in diabetes incidence as well as a decrease in both the quantity and affinity of HEL-specific IgG autoantibodies relative to 3A9 TCR:iHEL NOD.H2(k) mice. Notably, the decrease in autoantibodies due to the Chr12 locus was not restricted to the TCR transgenic model, as it was also observed in the non-transgenic NOD.H2(k) setting. Of importance, antibody affinity maturation upon immunization and re-challenge was also impeded in NOD.H2(k)-Chr12 congenic mice relative to NOD.H2(k) mice. Together, these results demonstrate that a genetic variant(s) present within the Chr12 locus plays a global role in modulating antibody affinity maturation.
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Afinidad de Anticuerpos , Autoanticuerpos/biosíntesis , Cromosomas de los Mamíferos/genética , Diabetes Mellitus Tipo 1/inmunología , Sitios Genéticos , Animales , Afinidad de Anticuerpos/genética , Autoanticuerpos/genética , Autoantígenos/genética , Autoantígenos/inmunología , Autoinmunidad/genética , Diabetes Mellitus Tipo 1/genética , Modelos Animales de Enfermedad , Sitios Genéticos/genética , Variación Genética , Humanos , Insulina/genética , Ratones , Ratones Congénicos , Ratones Endogámicos NOD , Ratones Transgénicos , Muramidasa/genética , Muramidasa/inmunología , RatasRESUMEN
Nanowires (NW) have been extensively studied for Shewanella spp. and Geobacter spp. and are mostly produced by Type IV pili or multiheme c-type cytochrome. Electron transfer via NW is the most studied mechanism in microbially induced corrosion, with recent interest in application in bioelectronics and biosensor. In this study, a machine learning (ML) based tool was developed to classify NW proteins. A manually curated 999 protein collection was developed as an NW protein dataset. Gene ontology analysis of the dataset revealed microbial NW is part of membranal proteins with metal ion binding motifs and plays a central role in electron transfer activity. Random Forest (RF), support vector machine (SVM), and extreme gradient boost (XGBoost) models were implemented in the prediction model and were observed to identify target proteins based on functional, structural, and physicochemical properties with 89.33%, 95.6%, and 99.99% accuracy. Dipetide amino acid composition, transition, and distribution protein features of NW are key important features aiding in the model's high performance.
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Particulate methane monooxygenase (pMMO), a membrane-bound enzyme having three subunits (α, ß, and γ) and copper-containing centers, is found in most of the methanotrophs that selectively catalyze the oxidation of methane into methanol. Active sites in the pMMO of Methylosinus trichosporium OB3b were determined by docking the modeled structure with ethylbenzene, toluene, 1,3-dibutadiene, and trichloroethylene. The docking energy between the modeled pMMO structure and ethylbenzene, toluene, 1,3-dibutadiene, and trichloroethylene was -5.2, -5.7, -4.2, and -3.8 kcal/mol, respectively, suggesting the existence of more than one active site within the monomeric subunits due to the presence of multiple binding sites within the pMMO monomer. The evaluation of tunnels and cavities of the active sites and the docking results showed that each active site is specific to the radius of the substrate. To increase the catalysis rates of methane in the pMMO of M. trichosporium OB3b, selected amino acid residues interacting at the binding site of ethylbenzene, toluene, 1,3-dibutadiene, and trichloroethylene were mutated. Based on screening the strain energy, docking energy, and physiochemical properties, five mutants were downselected, B:Leu31Ser, B:Phe96Gly, B:Phe92Thr, B:Trp106Ala, and B:Tyr110Phe, which showed the docking energy of -6.3, -6.7, -6.3, -6.5, and -6.5 kcal/mol, respectively, as compared to the wild type (-5.2 kcal/mol) with ethylbenzene. These results suggest that these five mutants would likely increase methane oxidation rates compared to wild-type pMMO.
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Methylosinus trichosporium , Tricloroetileno , Catálisis , Cobre/metabolismo , Metano/metabolismo , Methylosinus trichosporium/genética , Methylosinus trichosporium/metabolismo , Tolueno/metabolismo , Tricloroetileno/metabolismoRESUMEN
Sensing surface topography, an upsurge of signaling biomolecules, and upholding cellular homeostasis are the rate-limiting spatio-temporal events in microbial attachment and biofilm formation. Initially, a set of highly specialized proteins, viz. conditioning protein, directs the irreversible attachment of the microbes. Later signaling molecules, viz. autoinducer, take over the cellular communication phenomenon, resulting in a mature microbial biofilm. The mandatory release of conditioning proteins and autoinducers corroborated the existence of two independent mechanisms operating sequentially for biofilm development. However, both these mechanisms are significantly affected by the availability of the cofactor, e.g., Copper (Cu). Generally, the Cu concentration beyond threshold levels is detrimental to the anaerobes except for a few species of sulfate-reducing bacteria (SRB). Remarkably SRB has developed intricate ways to resist and thrive in the presence of Cu by activating numerous genes responsible for modifying the presence of more toxic Cu(I) to Cu(II) within the periplasm, followed by their export through the outer membrane. Therefore, the determinants of Cu toxicity, sequestration, and transportation are reconnoitered for their contribution towards microbial adaptations and biofilm formation. The mechanistic details revealing Cu as a quorum quencher (QQ) are provided in addition to the three pathways involved in the dissolution of cellular communications. This review articulates the Machine Learning based data curing and data processing for designing novel anti-biofilm peptides and for an in-depth understanding of QQ mechanisms. A pioneering data set has been mined and presented on the functional properties of the QQ homolog in Oleidesulfovibrio alaskensis G20 and residues regulating the multicopper oxidase properties in SRB.
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The production, characterization and bioactivities of exopolysaccharides (EPSs) from a thermophilic bacterium Geobacillus sp. strain WSUCF1 were investigated. Using glucose as a carbon source 525.7 mg/L of exoproduct were produced in a 40-L bioreactor at 60 °C. Two purified EPSs were obtained: EPS-1 was a glucomannan containing mannose and glucose in a molar ratio of 1:0.21, while EPS-2 was composed of mannan only. The molecular weights of both EPSs were estimated to be approximately 1000 kDa, their FTIR and NMR spectra indicated the presence of α-type glycosidic bonds in a linear structure, and XRD analysis indicated a low degree of crystallinity of 0.11 (EPS-1) and 0.27 (EPS-2). EPS-1 and EPS-2 demonstrated high degradation temperatures of 319 °C and 314 °C, respectively, and non-cytotoxicity to HEK-293 cells at 2 and 3 mg/mL, respectively. In addition, both showed antioxidant activities. EPSs from strain WSUCF1 may expand the applications of microorganisms isolated from extreme environments and provide a valuable resource for exploitation in biomedical fields such as drug delivery carriers.
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Geobacillus/química , Polisacáridos Bacterianos/biosíntesis , Temperatura , Reactores Biológicos , Geobacillus/metabolismo , Células HEK293 , Humanos , Polisacáridos Bacterianos/químicaRESUMEN
Various microorganisms thrive under extreme environments, like hot springs, hydrothermal vents, deep marine ecosystems, hyperacid lakes, acid mine drainage, high UV exposure, and more. To survive against the deleterious effect of these extreme circumstances, they form a network of biofilm where exopolysaccharides (EPSs) comprise a substantial part. The EPSs are often polyanionic due to different functional groups in their structural backbone, including uronic acids, sulfated units, and phosphate groups. Altogether, these chemical groups provide EPSs with a negative charge allowing them to (a) act as ligands toward dissolved cations as well as trace, and toxic metals; (b) be tolerant to the presence of salts, surfactants, and alpha-hydroxyl acids; and (c) interface the solubilization of hydrocarbons. Owing to their unique structural and functional characteristics, EPSs are anticipated to be utilized industrially to remediation of metals, crude oil, and hydrocarbons from contaminated wastewaters, mines, and oil spills. The biotechnological advantages of extremophilic EPSs are more diverse than traditional biopolymers. The present review aims at discussing the mechanisms and strategies for using EPSs from extremophiles in industries and environment bioremediation. Additionally, the potential of EPSs as fascinating biomaterials to mediate biogenic nanoparticles synthesis and treat multicomponent water contaminants is discussed.
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Firmicutes is almost a ubiquitous phylum. Several genera of this group, for instance, Geobacillus, are recognized for decomposing plant organic matter and for producing thermostable ligninolytic enzymes. Amplicon sequencing was used in this study to determine the prevalence and genetic diversity of the Firmicutes in two distinctly related environmental samples-South Dakota Landfill Compost (SDLC, 60 °C), and Sanford Underground Research Facility sediments (SURF, 45 °C). Although distinct microbial community compositions were observed, there was a dominance of Firmicutes in both the SDLC and SURF samples, followed by Proteobacteria. The abundant classes of bacteria in the SDLC site, within the phylum Firmicutes, were Bacilli (83.2%), and Clostridia (2.9%). In comparison, the sample from the SURF mine was dominated by the Clostridia (45.8%) and then Bacilli (20.1%). Within the class Bacilli, the SDLC sample had more diversity (a total of 11 genera with more than 1% operational taxonomic unit, OTU). On the other hand, SURF samples had just three genera, about 1% of the total population: Bacilli, Paenibacillus, and Solibacillus. With specific regard to Geobacillus, it was found to be present at a level of 0.07% and 2.5% in SURF and SDLC, respectively. Subsequently, culture isolations of endospore-forming Firmicutes members from these samples led to the isolation of a total of 117 isolates. According to colony morphologies, and identification based upon 16S rRNA and gyrB gene sequence analysis, we obtained 58 taxonomically distinct strains. Depending on the similarity indexes, a gyrB sequence comparison appeared more useful than 16S rRNA sequence analysis for inferring intra- and some intergeneric relationships between the isolates.
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Investigations on microbial electrocatalysis as a strategy for enhancing the rates of substrate utilization leading to enhanced yield of biomass and enhanced biofilm formation are reported. A thermophilic Geobacillus sp. strain WSUCF1 (60⯰C), a potential lignocellulose degrading microorganism was used as the electrocatalyst. Glucose, cellulose, and corn stover were used as the feedstocks. The results of this investigation showed that applying the oxidation potential of -0.383â¯mV (vs PRE) increased the glucose utilization and COD removal by 25.5% and 29.7% respectively. The bioelectrocatalysis strategy also increased the biomass yield by 81.2, 42.1, and 49.5% in the case of systems fed with glucose, cellulose, and corn stover, respectively, when compared with the systems without applied oxidation potential. This is the first work reporting the effects of applied oxidation potential on increasing the rates of degradation of lignocellulosic biomass and enhanced biofilm formation.
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Geobacillus , Biopelículas , Biomasa , Celulosa , Lignina , Zea maysRESUMEN
The mimicking of evolution on a laboratory timescale to enhance biocatalyst specificity, substrate utilization activity, and/or product formation, is an effective and well-established approach that does not involve genetic engineering or regulatory details of the microorganism. The present work employed an evolutionary adaptive approach to improve the lignocellulose deconstruction capabilities of the strain by inducing the expression of laccase, a multicopper oxidase, in Geobacillus sp. strain WSUCF1. This bacterium is highly efficient in depolymerizing unprocessed lignocellulose, needing no preprocessing/pretreatment of the biomasses. However, it natively produces low levels of laccase. After 15 rounds of serially adapting this thermophilic strain in the presence of unprocessed corn stover as the selective pressure, we recorded a 20-fold increase in catalytic laccase activity, at 9.23 ± 0.6 U/mL, in an adapted yet stable strain of Geobacillus sp. WSUCF1, compared with the initial laccase production (0.46 ± 0.04 U/mL) obtained with the unadapted strain grown on unprocessed corn stover before optimization. Chemical composition analysis demonstrated that lignin removal by the adapted strain was 22 wt.% compared with 6 wt.% removal by the unadapted strain. These results signify a favorable prospect for fast, cost competitive bulk production of this thermostable enzyme. Also, this work has practical importance, as this fast adaptation of the Geobacillus sp. strain WSUCF1 suggests the possibility of growing industrial quantities of Geobacillus sp. strain WSUCF1 cells as biocatalysts on reasonably inexpensive carbon sources for commercial use. This work is the first application of the adaptive laboratory evolution approach for developing the desired phenotype of enhanced ligninolytic capability in any microbial strain.
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Numerous microorganisms inhabiting harsh niches produce exopolysaccharides as a significant strategy to survive in extreme conditions. The exopolysaccharides synthesized by extremophiles possess distinctive characteristics due to the varied harsh environments which stimulate the microorganisms to produce these biopolymers. Despite many bioprocesses have been designed to yield exopolysaccharides, the production of exopolysaccharides by extremophiles is inefficient compared with mesophilic and neutrophilic exopolysaccharide producers. Meanwhile, the industrial development of novel extremophilic exopolysaccharides remains constrained due to the lack of exploration. In this review, we summarize the structure and properties of various exopolysaccharides produced by extremophiles, and also discuss potential metabolic and genetic engineering strategies for enhanced yield and modified structure of extremophilic exopolysaccharides. Special focus is given to the applications of extremophilic exopolysaccharides in the areas of biomedicine, food industry, and biomaterials via nano-techniques, casting and electrospinning.
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Geobacillus sp. WSUCF1 is a Gram-positive, spore-forming, aerobic and thermophilic bacterium, isolated from a soil sample obtained from a compost facility. Strain WSUCF1 demonstrated EPS producing capability using different sugars as the carbon source. The whole-genome analysis of WSUCF1 was performed to disclose the essential genes correlated with nucleotide sugar precursor biosynthesis, assembly of monosaccharide units, export of the polysaccharide chain, and regulation of EPS production. Both the biosynthesis pathway and export mechanism of EPS were proposed based on functional annotation. Additionally, the genome description of strain WSUCF1 suggests sophisticated systems for its adaptation under thermophilic conditions. The presence of genes associated with CRISPR-Cas system, quorum quenching lactonase, polyketide synthesis and arsenic resistance makes this strain a potential candidate for various applications in biotechnology and biomedicine. The present study indicates that strain WSUCF1 has promise as a thermophilic EPS producer for a broad range of industrial applications. To the best of our knowledge, this is the first report on genome analysis of a thermophilic Geobacillus species focusing on its EPS biosynthesis and transportation, which will likely pave the way for both enhanced yield and tailor-made EPS production by thermophilic bacteria.
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Genómica , Geobacillus/genética , Geobacillus/metabolismo , Polisacáridos Bacterianos/biosíntesis , Temperatura , Biotecnología , Geobacillus/fisiología , Estrés FisiológicoRESUMEN
The aim of this study was to investigate the effect of atmospheric pressure cold plasma on the microbial substrate utilization and biomass yield in a thermophilic strain. Geobacillus sp. strain WSUCF1, a thermophile capable of producing cellulolytic enzymes with higher activity was used for this investigation. Treatment with cold plasma for 4â¯min increased the rates of glucose utilization by 74% and biomass yield by 60% when compared with the control. WSUCF1 treated with plasma also displayed enhanced biofilm formation. This study for the first time, reports the use of cold plasma for enhancing the substrate utilization and biofilm formation in a thermophile.
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Geobacillus , Presión Atmosférica , Biomasa , Gases em Plasma , Especificidad por SustratoRESUMEN
Thermophiles are promising options to use as electrocatalysts for bioelectrochemical applications including microbial electrolysis. They possess several interesting characteristics such as ability to catalyze a broad range of substrates at better rates and over a broad range of operating conditions, and better electrocatalysis/electrogenic activity over mesophiles. However, a very limited number of investigations have been carried out to explore the microbial reactions/pathways and the molecular mechanisms that contribute to better electrocatalysis/electrolysis in thermophiles. Here, we review the electroactive characteristics of thermophiles, their electron transfer mechanisms, and molecular insights behind the choice of thermophiles for bioelectrochemical/electrolytic processes.
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Transporte de Electrón , ElectrólisisRESUMEN
Systemic lupus erythematosus is a prototypic model for B-cell epitope spread in autoimmunity. Autoantibodies to numerous molecularly distinct self-antigens emerge in a sequential manner over several years, leading to disease manifestations. Among the earliest autoantibodies to appear are those targeting phospholipid-binding proteins, particularly ß2-glycoprotein I. Notably, mice immunized with ß2-glycoprotein I and lipopolysaccharide develop a strong T cell response to ß2-glycoprotein I that is associated with autoantibody production and renal disease, similar to that seen in human SLE. Here we hypothesized that mice with murine systemic lupus erythematosus, whether induced or spontaneous, should have T cells that recognize ß2-glycoprotein I. We evaluated the response of splenic T cells from mice with induced (C57BL/6 and C3H/HeN) and spontaneous (MRL/lpr) systemic lupus erythematosus to peptides spanning the entire sequence of human ß2GPI. We found that mice with induced and spontaneous systemic lupus erythematosus recognize a common T cell epitope (peptide 31; LYRDTAVFECLPQHAMFG) in domain III of ß2-glycoprotein I. ß2GPI-reactive CD4+ T cells from the two models differed primarily in cytokine production: T cells from mice with induced SLE expressed IFN-γ, while T cells from MRL/lpr mice expressed both IL-17 and IFN-γ, indicating that IL-17-expressing T cells are not necessary for generating a ß2GPI-reactive T cell response. These data suggest that the generation of a ß2-glycoprotein I-reactive T cell response is shared by both induced and spontaneous models of systemic lupus erythematosus and that this T cell response may mediate epitope spread to autoantibodies in both models.