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1
Haggar, Axana, Muzaffar Hussain, Helena Lönnies, Mathias Herrmann, Anna Norrby-Teglund, and Jan-Ingmar Flock. "Extracellular Adherence Protein from Staphylococcus aureus Enhances Internalization into Eukaryotic Cells." Infection and Immunity 71, no. 5 (May 2003): 2310–17. http://dx.doi.org/10.1128/iai.71.5.2310-2317.2003.
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ABSTRACT In this study we have shown that Eap (extracellular adherence protein) plays a role in the internalization process of Staphylococcus aureus into eukaryotic cells. Eap is a protein that is mostly extracellularly and to a lesser extent is bound to the bacterial surface as a result of rebinding. Eap is able to bind to several plasma proteins, such as fibronectin, fibrinogen, and prothrombin. It has the capacity to form oligomers and is able to agglutinate S. aureus. A mutant strain, Newman mAH12 (eap:: Eryr), with a deficient eap gene was used in the present study. We have demonstrated that (i) strain Newman mAH12 could adhere to and become internalized to a higher extent by eukaryotic cells than the isogenic mutant, (ii) strain Newman mAH12 complemented with the eap gene displayed restoration of the internalization level, (iii) externally added Eap enhanced the internalization of laboratory and clinical S. aureus strains as well as of S. carnosus (a coagulase-negative species devoid of proteins important for internalization), and (iv) antibodies against Eap were able to block the internalization process in strain Newman mAH12 and clinical isolates. Eap, with its broad binding capacity and its surface localization, thus seems to contribute to the internalization of S. aureus into eukaryotic cells. We therefore propose a novel internalization pathway for S. aureus in which Eap plays an enhancing role.
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Bui, Long M. G., Peter Hoffmann, John D. Turnidge, Peter S. Zilm, and Stephen P. Kidd. "Prolonged Growth of a Clinical Staphylococcus aureus Strain Selects for a Stable Small-Colony-Variant Cell Type." Infection and Immunity 83, no. 2 (November 10, 2014): 470–81. http://dx.doi.org/10.1128/iai.02702-14.
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An undetermined feature ofStaphylococcus aureuspathogenesis is its persistence and then relapse of disease. This has been explained by its switch to alternative lifestyles, mainly as biofilm or small-colony variants (SCVs). Studying the native characteristics of SCVs has been problematic due to their reversion to the parental lifestyle. We have observed that for a number ofS. aureusstrains as they switch to an SCV lifestyle, there is the formation of an extracellular matrix. We focused our analysis on one strain, WCH-SK2. For bacterial survival in the host, the combination of low nutrients and the prolonged time frame forms a stress that selects for a specific cell type from the population. In this context, we used steady-state growth conditions with low nutrients and a controlled low growth rate for a prolonged time and with methylglyoxal. These conditions inducedS. aureusWCH-SK2 into a stable SCV cell type; the cells did not revert after subculturing. Analysis revealed these cells possessed a metabolic and surface profile that was different from those of previously described SCVs or biofilm cells. The extracellular matrix was protein and extracellular DNA but not polysaccharide. The SCV cells induced expression of certain surface proteins (such as Ebh) and synthesis of lantibiotics while downregulating factors that stimulate the immune response (leucocidin, capsule, and carotenoid). Our data reveal cell heterogeneity within anS. aureuspopulation and under conditions that resemble long-term survival in the host have identified a previously unnoticedS. aureuscell type with a distinctive metabolic and molecular profile.
3
Palma, Marco, Axana Haggar, and Jan-Ingmar Flock. "Adherence of Staphylococcus aureus Is Enhanced by an Endogenous Secreted Protein with Broad Binding Activity." Journal of Bacteriology 181, no. 9 (May 1, 1999): 2840–45. http://dx.doi.org/10.1128/jb.181.9.2840-2845.1999.
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ABSTRACT A novel mechanism for enhancement of adherence ofStaphylococcus aureus to host components is described. A secreted protein, Eap (extracellular adherence protein), was purified from the supernatant of S. aureus Newman and found to be able to bind to at least seven plasma proteins, e.g., fibronectin, the α-chain of fibrinogen, and prothrombin, and to the surface ofS. aureus. Eap bound much less to cells ofStaphylococcus epidermidis, Streptococcus mutans, or Escherichia coli. The protein can form oligomeric forms and is able to cause agglutination of S. aureus. Binding of S. aureus to fibroblasts and epithelial cells was significantly enhanced by addition of Eap, presumably due to its affinity both for plasma proteins on the cells and for the bacteria.
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Hussain, Muzaffar, Axana Haggar, Christine Heilmann, Georg Peters, Jan-Ingmar Flock, and Mathias Herrmann. "Insertional Inactivation of eap in Staphylococcus aureus Strain Newman Confers Reduced Staphylococcal Binding to Fibroblasts." Infection and Immunity 70, no. 6 (June 2002): 2933–40. http://dx.doi.org/10.1128/iai.70.6.2933-2940.2002.
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ABSTRACT To initiate invasive infection, Staphylococcus aureus must adhere to host substrates, such as the extracellular matrix or eukaryotic cells, by virtue of different surface proteins (adhesins). Recently, we identified a 60-kDa cell-secreted extracellular adherence protein (Eap) of S. aureus strain Newman with broad-spectrum binding characteristics (M. Palma, A. Haggar, and J. I. Flock, J. Bacteriol. 181:2840-2845, 1999), and we have molecularly confirmed Eap to be an analogue of the previously identified major histocompatibility complex class II analog protein (Map) (M. Hussain, K. Becker, C. von Eiff, G. Peter, and M. Herrmann, Clin. Diagn. Lab. Immunol. 8:1281-1286, 2001). Previous analyses of the Eap/Map function performed with purified protein did not allow dissection of its precise role in the complex situation of the staphylococcal whole cell presenting several secreted and wall-bound adhesins. Therefore, the role of Eap was investigated by constructing a stable eap::ermB deletion in strain Newman and by complementation of the mutant. Patterns of extracted cell surface proteins analyzed both by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by Western ligand assays with various adhesive matrix molecules clearly confirmed the absence of Eap in the mutant. However, binding and adhesion tests using whole staphylococcal cells demonstrated that both the parent and mutant strains bound equally well to fibronectin- and fibrinogen-coated surfaces, possibly due to their recognition by other staphylococcal adhesins. Furthermore, Eap mediated staphylococcal agglutination of both wild-type and mutant cells. In contrast, the mutant adhered to a significantly lesser extent to cultured fibroblasts (P < 0.001) than did the wild type, while adherence was restorable upon complementation. Furthermore, adherence to both epithelial cells (P < 0.05) and fibroblasts (not significant) could be blocked with antibodies against Eap, whereas preimmune serum was not active. In conclusion, Eap may contribute to pathogenicity by promoting adhesion of whole staphylococcal cells to complex eukaryotic substrates.
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Hinek, A., and M. Rabinovitch. "67-kD elastin-binding protein is a protective "companion" of extracellular insoluble elastin and intracellular tropoelastin." Journal of Cell Biology 126, no. 2 (July 15, 1994): 563–74. http://dx.doi.org/10.1083/jcb.126.2.563.
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The 67-kD elastin-binding protein (EBP) mediates cell adhesion to elastin and elastin fiber assembly, and it is similar, if not identical, to the 67-kD enzymatically inactive, alternatively spliced beta-galactosidase. The latter contains an elastin binding domain (S-GAL) homologous both to the aorta EBP and to NH2-terminal sequences of serine proteinases (Hinek, A., M. Rabinovitch, F. W. Keeley, and J. Callahan. 1993. J. Clin. Invest. 91:1198-1205). We now confirm the functional importance of this homology by showing that elastolytic activity of a representative serine elastase, porcine pancreatic elastase, was prevented by an antibody (anti-S-GAL) and by competing with purified EBP or S-GAL peptide. Immunohistochemistry of adult aorta indicates that the EBP exists as a permanent component of mature elastic fibers. This observation, together with the in vitro studies, suggests that the EBP could protect insoluble elastin from extracellular proteolysis and contribute to the extraordinary stability of this protein. Double immunolabeling of fetal lamb aorta with anti-S-GAL and antitropoelastin antibodies demonstrated, under light and electron microscopy, intracellular colocalization of the proteins in smooth muscle cells (SMC). Incubation of SMC with galactosugars to dissociate tropoelastin from EBP caused intracellular aggregation of tropoelastin. A tropoelastin/EBP complex was extracted from SMC lysates by coimmunoprecipitation and cross-linking, and its functional significance was addressed by showing that its dissociation by galactosugars caused degradation of tropoelastin by endogenous serine proteinase(s). This suggests that the EBP may also serve as a "companion" to intracellular tropoelastin, protecting this highly hydrophobic protein from self-aggregation and proteolytic degradation.
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Otto, Ben R., Silvy J. M. van Dooren, Jan H. Nuijens, Joen Luirink, and Bauke Oudega. "Characterization of a Hemoglobin Protease Secreted by the Pathogenic Escherichia coli Strain EB1." Journal of Experimental Medicine 188, no. 6 (September 21, 1998): 1091–103. http://dx.doi.org/10.1084/jem.188.6.1091.
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Many pathogenic bacteria can use heme compounds as a source of iron. Pathogenic Escherichia coli strains are capable of using hemoglobin as an iron source. However, the mechanism of heme acquisition from hemoglobin is not understood for this microorganism. We present the first molecular characterization of a hemoglobin protease (Hbp) from a human pathogenic E. coli strain. The enzyme also appeared to be a heme-binding protein. Affinity purification of this bifunctional protein enabled us to identify the extracellular gene product, and to clone and analyze its gene. A purification procedure developed for Hbp allowed us to perform functional studies. The protein interacted with hemoglobin, degraded it and subsequently bound the released heme. These results suggest that the protein is involved in heme acquisition by this human pathogen. Hbp belongs to the so-called IgA1 protease-like proteins, as indicated by the kinetics of its membrane transfer and DNA sequence similarity. The gene of this protein appears to be located on the large pColV-K30 episome, that only has been isolated from human and animal pathogens. All these characteristics indicate that Hbp may be an important virulence factor that may play a significant role in the pathogenesis of E. coli infections.
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Lee, Y. M., L. H. Miau, C. J. Chang, and S. C. Lee. "Transcriptional induction of the alpha-1 acid glycoprotein (AGP) gene by synergistic interaction of two alternative activator forms of AGP/enhancer-binding protein (C/EBP beta) and NF-kappaB or Nopp140." Molecular and Cellular Biology 16, no. 8 (August 1996): 4257–63. http://dx.doi.org/10.1128/mcb.16.8.4257.
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Alpha-1 acid glycoprotein/enhancer-binding protein (AGP/EBP) (C/EBPbeta), a member of the C/EBP family, is one of the key transcription factors responsible for the induction of a wide array of genes, some of which are expressed during the acute-phase response. Both activator and repressor were shown to be encoded by the intronless agp/ebp or its rat and human homologs, which contain a common bZIP domain at their C-terminal regions. Expression of the AGP gene (agp) is regulated by AGP/EBP in liver during the acute-phase response. However, the molecular mechanism for this regulation is poorly understood. The experiments reported here demonstrate that two activator forms of AGP/EBP, one of which has an additional 21 amino acids at its N-terminal region, are expressed in liver as well as in a number of cell lines. We have also demonstrated that NF-kappaB and a phosphoprotein of 140 kDa, Nopp140, interact with different AGP/EBP activators synergistically, which results in induction of the agp gene in an AGP/EBP-binding-motif-dependent manner. Furthermore, extracellular stimuli that are known to be NF-kappaB inducers can selectively activate the agp gene by cooperating with one of the two activator forms of AGP/EBP. The physiological significance of differential regulation for the function of two activator forms of AGP/EBP through selective interaction with different transcription factors is discussed.
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Jiang, J. G., and R. Zarnegar. "A novel transcriptional regulatory region within the core promoter of the hepatocyte growth factor gene is responsible for its inducibility by cytokines via the C/EBP family of transcription factors." Molecular and Cellular Biology 17, no. 10 (October 1997): 5758–70. http://dx.doi.org/10.1128/mcb.17.10.5758.
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Hepatocyte growth factor (HGF) is an inducible cytokine that is essential for the normal growth and development of various tissues, such as the liver. To decipher the molecular mechanisms that regulate HGF gene induction at the transcriptional level, we carried out in vitro and in vivo studies on the mouse HGF gene promoter. We have identified a novel regulatory element, located between -6 and +7 bp (from the transcription start site) in the HGF basal promoter region, which binds to inducible transcription factors and dictates responsiveness to extracellular stimuli that activate this gene. The core binding sequence for the inducible cis-acting factors was determined to be TTTGCAA (-4 to +3 bp) within the HGF promoter. Competition and gel mobility supershift assays showed that these binding complexes are composed of C/EBPbeta (CCAAT/enhancer-binding protein beta) and C/EBPdelta. DNA binding analysis also revealed that the binding site for the C/EBP family of transcription factors in the HGF promoter region overlaps that of another binding protein (complex C1), which binds specifically to a novel sequence with a core binding site of ACCGGT located adjacent to the C/EBP site (-9 to -4 bp). C1 binds to this region of the promoter and represses the inducible upregulation by C/EBP through direct competition for their individual binding sites. Partial hepatectomy, which is known to activate HGF gene expression in the liver, increased C/EBP (especially C/EBPbeta) binding activity to this region of the HGF promoter. Thus, our present results provide a mechanistic explanation for the transcriptional induction of the HGF gene by extracellular signals (i.e., cytokines) that induce tissue growth and regeneration.
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Kida, Yutaka, Hiroyoshi Inoue, Takashi Shimizu, and Koichi Kuwano. "Serratia marcescens Serralysin Induces Inflammatory Responses through Protease-Activated Receptor 2." Infection and Immunity 75, no. 1 (October 16, 2006): 164–74. http://dx.doi.org/10.1128/iai.01239-06.
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ABSTRACT The Serratia marcescens-derived protease serralysin is considered to play an important role in the pathogenesis of infection. Protease-activated receptor 2 (PAR-2) is activated by trypsin and also several other trypsin-like serine proteases, leading to the modulation of inflammatory and immune responses. However, little is known about the activation of PAR-2 by bacterial proteases and its roles in bacterial infection. In this study, we investigated whether S. marcescens serralysin activates host inflammatory responses through PAR-2. Our results demonstrated that serralysin induces interleukin-6 (IL-6) and IL-8 mRNA expression in a human lung squamous cell carcinoma, EBC-l cells. In addition, serralysin activated activator protein 1 (AP-1)-, CCAAT/enhancer-binding protein (C/EBP)-, and nuclear factor-κB (NF-κB)-driven promoters in EBC-1 cells. An electrophoretic mobility shift assay showed that serralysin activates the binding of AP-1, C/EBPβ, and NF-κB in the cells. Inactivation of serralysin resulted in the failure of transactivation of AP-1-, C/EBP-, and NF-κB-driven promoters in the cells. Furthermore, serralysin activated AP-1-, C/EBP-, and NF-κB-driven promoters via PAR-2 in HeLa cells. PAR-2 antagonist peptides decreased serralysin-induced transactivation of AP-1-, C/EBP-, and NF-κB-driven promoters in EBC-1 cells. Considered together, these results suggest that serralysin requires PAR-2 to activate the critical transcription factors AP-1, C/EBPβ, and NF-κB for host inflammatory responses.
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Kwak, Dong Hoon, Ji-Hye Lee, Dong-Gun Kim, Taesoo Kim, Kwang Jin Lee, and Jin Yeul Ma. "Inhibitory Effects of Hwangryunhaedok-Tang in 3T3-L1 Adipogenesis by Regulation of Raf/MEK1/ERK1/2 Pathway and PDK1/Akt Phosphorylation." Evidence-Based Complementary and Alternative Medicine 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/413906.
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Hwangryunhaedok-tang (HRT) has been long used as traditional medicine in Asia. However, inhibitory role of HRT is unclear in early stage of 3T3-L1 adipocyte differentiation related to signaling. In the present study, we investigated the inhibitory effects of HRT on upstream signaling of peroxisome proliferation-activity receptor-γ(PPAR-γ) and CCAAT/enhancer binding protein-β(C/EBP-β) expression in differentiation of 3T3-L1 preadipocytes. We found that HRT significantly inhibited the adipocyte differentiation by downregulating several adipocyte-specific transcription factors including PPAR-γ, C/EBP-α, and C/EBP-βin 3T3-L1 preadipocytes. Furthermore, we observed that HRT markedly inhibited the differentiation media-mediated phosphorylation of Raf/extracellular mitogen-activated protein kinase 1 (MEK1)/signal-regulated protein kinase 1/2 (ERK1/2) and phosphorylation of phosphoinositide-dependent kinase 1 (PDK1)/Akt. These results indicate that anti-adipogenesis mechanism involves the downregulation of the major transcription factors of adipogenesis including PPAR-γand C/EBP-αthrough inhibition of Raf/MEK1/ERK1/2 phosphorylation and PDK1/Akt phosphorylation by HRT. Furthermore, high performance liquid chromatography (HPLC) analysis showed HRT contains active antiobesity constituents such as palmatine, berberine, geniposide, baicalin, baicalein, and wogonin. Taken together, this study suggested that anti-adipogenesis effects of HRT were accounted by downregulation of Raf/MEK1/ERK1/2 pathway and PDK1/Akt pathway during 3T3-L1 adipocyte differentiation.
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Son, Gwang-ic, Eunil Lee, Mari Kim, Seoeun Lee, Yesol Moon, and Joonhee Kim. "Elevated barometric pressure suppresses cell proliferation by delaying the G2/M phase and weakening integrin-mediated cell adhesion and actin assembly." Archives of Biological Sciences, no. 00 (2023): 19. http://dx.doi.org/10.2298/abs230313019s.
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Human cells are continuously exposed to various stress factors in their physiological environment. Evidence suggests that certain mechanical stress can affect cell cycle progression and cell proliferation. However, the signaling pathways involved in this process are not well understood. To investigate this, we developed a pressure chamber capable of producing an elevated barometric pressure (EBP) environment of 2?atmospheric absolute pressure (ATA). We then studied the effect of EBP on cell proliferation and its underlying mechanism. Our results show that EBP inhibited cell proliferation by delaying the G2/M phase. Specifically, EBP reduced the expression levels of cell adhesion-related genes and downregulated integrin subunit genes, resulting in weaker interaction between cells and extracellular matrix proteins. In addition, Ras-related C3 botulinum toxin substrate 1 (Rac1) and cell division control protein 42 homolog (Cdc42) activity was suppressed, and actin assembly was decreased. These findings suggest that the EBP-mediated G2/M phase delay is due to attenuated cell adhesion and actin cytoskeleton assembly, leading to the inhibition of cell proliferation. Our results provide a crucial molecular mechanism for how certain pressure (changes) can negatively regulate cell proliferation. These findings could potentially be used in the future to develop a pressure therapy to inhibit cell proliferation in cancer patients.
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Ghrayeb, Mnar, Shahar Hayet, Neta Lester-Zer, Yael Levi-Kalisman, and Liraz Chai. "Fibrilar Polymorphism of the Bacterial Extracellular Matrix Protein TasA." Microorganisms 9, no. 3 (March 4, 2021): 529. http://dx.doi.org/10.3390/microorganisms9030529.
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Functional amyloid proteins often appear as fibers in extracellular matrices of microbial soft colonies. In contrast to disease-related amyloid structures, they serve a functional goal that benefits the organism that secretes them, which is the reason for the title “functional”. Biofilms are a specific example of a microbial community in which functional amyloid fibers play a role. Functional amyloid proteins contribute to the mechanical stability of biofilms and mediate the adhesion of the cells to themselves as well as to surfaces. Recently, it has been shown that functional amyloid proteins also play a regulatory role in biofilm development. TasA is the major proteinaceous fibrilar component of the extracellular matrix of biofilms made of the soil bacterium and Gram-positive Bacillus subtilis. We have previously shown, as later corroborated by others, that in acidic solutions, TasA forms compact aggregates that are composed of tangled fibers. Here, we show that in a neutral pH and above a certain TasA concentration, the fibers of TasA are elongated and straight and that they bundle up in highly concentrated salt solutions. TasA fibers resemble the canonic amyloid morphology; however, these fibers also bear an interesting nm-scale periodicity along the fiber axis. At the molecular level, TasA fibers contain a twisted β-sheet structure, as indicated by circular dichroism measurements. Our study shows that the morphology of TasA fibers depends on the environmental conditions. Different fibrilar morphologies may be related with different functional roles in biofilms, ranging from granting biofilms with a mechanical support to acting as antibiotic agents.
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Chamorro-Jorganes, Aranzazu, Laura Calleros, Mercedes Griera, Marta Saura, Alicia Luengo, D. Rodriguez-Puyol, and M. Rodriguez-Puyol. "Fibronectin upregulates cGMP-dependent protein kinase type Iβ through C/EBP transcription factor activation in contractile cells." American Journal of Physiology-Cell Physiology 300, no. 3 (March 2011): C683—C691. http://dx.doi.org/10.1152/ajpcell.00251.2010.
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The nitric oxide (NO)-soluble guanylate cyclase (sGC) pathway exerts most of its cellular actions through the activation of the cGMP-dependent protein kinase (PKG). Accumulation of extracellular matrix is one of the main structural changes in pathological conditions characterized by a decreased activity of this pathway, such as hypertension, diabetes, or aging, and it is a well-known fact that extracellular matrix proteins modulate cell phenotype through the interaction with membrane receptors such as integrins. The objectives of this study were 1) to evaluate whether extracellular matrix proteins, particularly fibronectin (FN), modulate PKG expression in contractile cells, 2) to analyze the mechanisms involved, and 3) to evaluate the functional consequences. FN increased type I PKG (PKG-I) protein content in human mesangial cells, an effect dependent on the interaction with β1-integrin. The FN upregulation of PKG-I protein content was due to increased mRNA expression, determined by augmented transcriptional activity of the PKG-I promoter region. Akt and the transcription factor CCAAT enhancer-binding protein (C/EBP) mediated the genesis of these changes. FN also increased PKG-I in another type of contractile cell, rat vascular smooth muscle cells (RVSMC). Tirofiban, a pharmacological analog of FN, increased PKG-I protein content in RVSMC and rat aortic walls and magnified the hypotensive effect of dibutyryl cGMP in conscious Wistar rats. The present results provide evidence of a mechanism able to increase PKG-I protein content in contractile cells. Elucidation of this novel mechanism provides a rationale for future pharmacotherapy in certain vascular diseases.
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Schraw, Wayne, Mark S. McClain, and Timothy L. Cover. "Kinetics and Mechanisms of Extracellular Protein Release by Helicobacter pylori." Infection and Immunity 67, no. 10 (October 1, 1999): 5247–52. http://dx.doi.org/10.1128/iai.67.10.5247-5252.1999.
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ABSTRACT To investigate the kinetics and mechanisms of extracellular protein release by Helicobacter pylori, we analyzed the entry of metabolically radiolabeled bacterial proteins into broth culture supernatant. At early time points, vacuolating cytotoxin (VacA) constituted a major extracellular protein. Subsequently, culture supernatants accumulated many proteins that were components of intact bacterial cells. This nonselective release of proteins was associated with a decreasing turbidity of cultures and loss of bacterial viability, indicative of an autolytic process. The rates of VacA secretion and autolysis were each influenced by medium composition, and therefore these may be regulated phenomena. Extracellular release of proteins by H. pylori may be an important adaptation that facilitates the persistence of H. pylori in the human gastric mucus layer. Moreover, entry of proinflammatory proteins into the gastric mucosa may contribute to the induction of a mucosal inflammatory response.
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Tetz, George, and Victor Tetz. "Bacterial Extracellular DNA Promotes β-Amyloid Aggregation." Microorganisms 9, no. 6 (June 15, 2021): 1301. http://dx.doi.org/10.3390/microorganisms9061301.
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Alzheimer’s disease is associated with prion-like aggregation of the amyloid β (Aβ) peptide and the subsequent accumulation of misfolded neurotoxic aggregates in the brain. Therefore, it is critical to clearly identify the factors that trigger the cascade of Aβ misfolding and aggregation. Numerous studies have pointed out the association between microorganisms and their virulence factors and Alzheimer’s disease; however, their exact mechanisms of action remain unclear. Recently, we discovered a new pathogenic role of bacterial extracellular DNA, triggering the formation of misfolded Tau aggregates. In this study, we investigated the possible role of DNA extracted from different bacterial and eukaryotic cells in triggering Aβ aggregation in vitro. Interestingly, we found that the extracellular DNA of some, but not all, bacteria is an effective trigger of Aβ aggregation. Furthermore, the acceleration of Aβ nucleation and elongation can vary based on the concentration of the bacterial DNA and the bacterial strain from which this DNA had originated. Our findings suggest that bacterial extracellular DNA might play a previously overlooked role in the Aβ protein misfolding associated with Alzheimer’s disease pathogenesis. Moreover, it highlights a new mechanism of how distantly localized bacteria can remotely contribute to protein misfolding and diseases associated with this process. These findings might lead to the use of bacterial DNA as a novel therapeutic target for the prevention and treatment of Alzheimer’s disease.
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Rana, B., D. Mischoulon, Y. Xie, N. L. Bucher, and S. R. Farmer. "Cell-extracellular matrix interactions can regulate the switch between growth and differentiation in rat hepatocytes: reciprocal expression of C/EBP alpha and immediate-early growth response transcription factors." Molecular and Cellular Biology 14, no. 9 (September 1994): 5858–69. http://dx.doi.org/10.1128/mcb.14.9.5858-5869.1994.
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Previous investigations have shown that culture of freshly isolated hepatocytes under conventional conditions, i.e., on dried rat tail collagen in the presence of growth factors, facilitates cell growth but also causes an extensive down-regulation of most liver-specific functions. This dedifferentiation process can be prevented if the cells are cultured on a reconstituted basement membrane gel matrix derived from the Englebreth-Holm-Swarm mouse sarcoma tumor (EHS gel). To gain insight into the mechanisms regulating this response to extracellular matrix, we are analyzing the activities of two families of transcription factors, C/EBP and AP-1, which control the transcription of hepatic and growth-responsive genes, respectively. We demonstrate that isolation of hepatocytes from the normal quiescent rat liver by collagenase perfusion activates the immediate-early growth response program, as indicated by increased expression of c-jun, junB, c-fos, and c-myc mRNAs. Adhesion of these activated cells to dried rat tail collagen augments the elevated levels of these mRNAs for the initial 1 to 2 h postplating; junB and c-myc mRNA levels then drop steeply, with junB returning to normal quiescence and the c-myc level remaining slightly elevated during the 3-day culture period. Levels of c-jun mRNA and AP-1 DNA binding activity, however, remain elevated from the outset, while C/EBP alpha mRNA expression is down-regulated, resulting in a decrease in the steady-state levels of the 42- and 30-kDa C/EBP alpha polypeptides and C/EBP alpha DNA binding activity. In contrast, C/EBP beta mRNA production remains at near-normal hepatic levels for 5 to 8 days of culture, although its DNA binding activity decreases severalfold during this time. Adhesion of hepatocytes to the EHS gel for the same period of time dramatically alters this program: it arrests growth and inhibits AP-1 DNA binding activity and the expression of c-jun, junB, and c-myc mRNAs, but, in addition, it restores C/EBP alpha mRNA and protein as well as C/EBP alpha and C/EBP beta DNA binding activities to the abundant levels present in freshly isolated hepatocytes. These changes are not due merely to growth inhibition, because suppression of hepatocyte proliferation on collagen by epidermal growth factor starvation or addition of transforming growth factor beta does not inhibit AP-1 activity or restore C/EBP alpha DNA binding activity to normal hepatic levels. These data suggest that expression of the normal hepatic phenotype requires that hepatocytes exist in a G0 state of growth arrest, facilitated here by adhesion of cells to the EHS gel, in order to express high levels of hepatic transcription factors such as C/EBP alpha.
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Rana, B., D. Mischoulon, Y. Xie, N. L. Bucher, and S. R. Farmer. "Cell-extracellular matrix interactions can regulate the switch between growth and differentiation in rat hepatocytes: reciprocal expression of C/EBP alpha and immediate-early growth response transcription factors." Molecular and Cellular Biology 14, no. 9 (September 1994): 5858–69. http://dx.doi.org/10.1128/mcb.14.9.5858.
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Previous investigations have shown that culture of freshly isolated hepatocytes under conventional conditions, i.e., on dried rat tail collagen in the presence of growth factors, facilitates cell growth but also causes an extensive down-regulation of most liver-specific functions. This dedifferentiation process can be prevented if the cells are cultured on a reconstituted basement membrane gel matrix derived from the Englebreth-Holm-Swarm mouse sarcoma tumor (EHS gel). To gain insight into the mechanisms regulating this response to extracellular matrix, we are analyzing the activities of two families of transcription factors, C/EBP and AP-1, which control the transcription of hepatic and growth-responsive genes, respectively. We demonstrate that isolation of hepatocytes from the normal quiescent rat liver by collagenase perfusion activates the immediate-early growth response program, as indicated by increased expression of c-jun, junB, c-fos, and c-myc mRNAs. Adhesion of these activated cells to dried rat tail collagen augments the elevated levels of these mRNAs for the initial 1 to 2 h postplating; junB and c-myc mRNA levels then drop steeply, with junB returning to normal quiescence and the c-myc level remaining slightly elevated during the 3-day culture period. Levels of c-jun mRNA and AP-1 DNA binding activity, however, remain elevated from the outset, while C/EBP alpha mRNA expression is down-regulated, resulting in a decrease in the steady-state levels of the 42- and 30-kDa C/EBP alpha polypeptides and C/EBP alpha DNA binding activity. In contrast, C/EBP beta mRNA production remains at near-normal hepatic levels for 5 to 8 days of culture, although its DNA binding activity decreases severalfold during this time. Adhesion of hepatocytes to the EHS gel for the same period of time dramatically alters this program: it arrests growth and inhibits AP-1 DNA binding activity and the expression of c-jun, junB, and c-myc mRNAs, but, in addition, it restores C/EBP alpha mRNA and protein as well as C/EBP alpha and C/EBP beta DNA binding activities to the abundant levels present in freshly isolated hepatocytes. These changes are not due merely to growth inhibition, because suppression of hepatocyte proliferation on collagen by epidermal growth factor starvation or addition of transforming growth factor beta does not inhibit AP-1 activity or restore C/EBP alpha DNA binding activity to normal hepatic levels. These data suggest that expression of the normal hepatic phenotype requires that hepatocytes exist in a G0 state of growth arrest, facilitated here by adhesion of cells to the EHS gel, in order to express high levels of hepatic transcription factors such as C/EBP alpha.
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Notley, Colleen, Shawn Tinlin, Lisa Sawyer, Megan Begbie, and David Lillicrap. "The Factor VIII Acute Phase Response Requires the Participation of NFκB and C/EBP." Thrombosis and Haemostasis 84, no. 08 (2000): 216–22. http://dx.doi.org/10.1055/s-0037-1613999.
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SummaryCoagulation Factor VIII is an acute phase protein in humans that has recently been shown to be transcriptionally responsive to interleukin-6. In this study, we have demonstrated that the human Factor VIII promoter is activated in cultured hepatocytes exposed to bacterial lipopolysaccharide (LPS). Deletion analysis has narrowed the LPS-responsive element of the Factor VIII promoter to a small region which contains two C/EBP binding sites and an adjacent NFκB binding site. Mutation of the downstream C/EBP site reduces LPS-responsiveness by ∼50%, while mutation of the NFκB binding site completely eliminates LPS-responsiveness. While binding of C/EBPβ and NFκB is still observed in gel retardation studies using acute phase nuclear extracts and a probe containing mutations to the downstream C/EBP site, neither NFκB nor C/EBP appear to bind to a probe in which the NFκB site has been mutated. Conservation of this region of the Factor VIII promoter in species which exhibit an increase in Factor VIII levels in response to inflammatory stimuli suggests that these transcription factor binding sites are important for normal regulation of the Factor VIII gene under conditions of stress.
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Ashraf, Noreen, Fiaz Ahmad, Yandu Lu, and Da-Chuan Yin. "Bacterial extracellular protein interacts with silver ions to produce protein-encapsulated bactericidal AgNPs." Process Biochemistry 106 (July 2021): 120–29. http://dx.doi.org/10.1016/j.procbio.2021.04.006.
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Abbasi, Razan, Reem Mousa, Noa Dekel, Hadar Amartely, Tsafi Danieli, Mario Lebendiker, Yael Levi‐Kalisman, Deborah E. Shalev, Norman Metanis, and Liraz Chai. "The Bacterial Extracellular Matrix Protein TapA Is a Two‐Domain Partially Disordered Protein." ChemBioChem 20, no. 3 (December 13, 2018): 355–59. http://dx.doi.org/10.1002/cbic.201800634.
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Serio, Kenneth J., K. Veera Reddy, and Timothy D. Bigby. "Lipopolysaccharide induces 5-lipoxygenase-activating protein gene expression in THP-1 cells via a NF-κB and C/EBP-mediated mechanism." American Journal of Physiology-Cell Physiology 288, no. 5 (May 2005): C1125—C1133. http://dx.doi.org/10.1152/ajpcell.00296.2004.
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We examined induced expression of the 5-lipoxygenase-activating protein (FLAP), which is critical for leukotriene synthesis in mononuclear phagocytes. Prolonged exposure to the bacterial component, lipopolysaccharide (LPS), increased FLAP gene transcription, mRNA expression, and protein expression in the human monocyte-like THP-1 cell line. Activation and inhibition of the NF-κB pathway modulated LPS induction of FLAP gene expression. An NF-κB-mediated mechanism of action was supported by overexpression of dominant-negative IκBα and p50/p65 proteins. EMSA/supershift and DNase I footprint analyses revealed that p50 binds to an NF-κB site located in the proximal FLAP promoter, while chromatin immunoprecipitation assays demonstrated that LPS induced binding of p50 but not of p65. Moreover, EMSA/supershift analyses demonstrated that LPS induced time-dependent binding of THP-1 nuclear extracts (containing p50) to this promoter region. Mutation of the NF-κB site decreased basal promoter activity and abolished the p50- and p65-associated induction. EMSA/supershift analyses also demonstrated that LPS induced binding of THP-1 nuclear extracts [containing CCAAT/enhancer binding protein (C/EBP)-α, -δ, and -ε] to a C/EBP site located adjacent to the NF-κB site in the FLAP promoter. We conclude that LPS enhances FLAP gene expression via both NF-κB- and C/EBP-mediated transcriptional mechanisms in mononuclear phagocytes.
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Lin, Lin, Teresa M. Stringfield, Xianglin Shi, and Yan Chen. "Arsenite induces a cell stress-response gene, RTP801, through reactive oxygen species and transcription factors Elk-1 and CCAAT/enhancer-binding protein." Biochemical Journal 392, no. 1 (November 8, 2005): 93–102. http://dx.doi.org/10.1042/bj20050553.
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RTP801 is a newly discovered stress-response gene that is induced by hypoxia and other cell stress signals. Arsenic is a heavy metal that is linked to carcinogenesis in humans. Here, we investigated the mechanism by which arsenic induces RTP801 transcription. In HaCaT human keratinocytes, arsenite was able to induce a rapid rise in the RTP801 mRNA level. Correspondingly, arsenite treatment was capable of stimulating a 2.5 kb human RTP801 promoter. Such a stimulatory effect was inhibited by co-expression of superoxide dismutase or glutathione peroxidase, and was abrogated by N-acetylcysteine, implying that ROS (reactive oxygen species) were involved in transcriptional regulation of the RTP801 gene. A series of deletion studies with the promoter revealed a critical arsenic-responsive region between −1057 and −981 bp of the promoter. Point mutations of the putative Elk-1 site and the C/EBP (CCAAT/enhancer-binding protein) site within this region were able to reduce the stimulatory effect of arsenite, indicating that Elk-1 and C/EBP are involved in transcriptional regulation of the RTP801 gene by arsenite. Furthermore, a gel mobility-shift assay demonstrated that arsenite was able to mount the rapid formation of a protein complex that bound the arsenic-responsive region as well as the C/EBP-containing sequence. The arsenite stimulation on RTP801 transcription was partly mediated by the ERK (extracellular-signal-regulated kinase) pathway, since the effect of RTP801 was inhibited by a selective ERK inhibitor. In addition, overexpression of Elk-1 and C/EBPβ was able to elevate the promoter activity. Therefore these studies indicate that RTP801 is a transcriptional target of arsenic in human keratinocytes, and that arsenic and ROS production are linked to Elk-1 and C/EBP in the transcriptional control.
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Chen, Baoyu, Tatyana A. Sysoeva, Saikat Chowdhury, and B. Tracy Nixon. "Regulation and action of the bacterial enhancer-binding protein AAA+ domains." Biochemical Society Transactions 36, no. 1 (January 22, 2008): 89–93. http://dx.doi.org/10.1042/bst0360089.
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Bacterial EBPs (enhancer-binding proteins) play crucial roles in regulating cellular responses to environmental changes, in part by providing efficient control over σ54-dependent gene transcription. The AAA+ (ATPase associated with various cellular activites) domain of the EBPs, when assembled into a ring, uses energy from ATP binding, hydrolysis and product release to remodel the σ54–RNAP (RNA polymerase) holoenzyme so that it can transition from closed to open form at promoter DNA. The assembly, and hence activity, of these ATPases are regulated by many different signal transduction mechanisms. Recent advances in solution scattering techniques, when combined with high-resolution structures and biochemical data, have enabled us to obtain mechanistic insights into the regulation and action of a subset of these σ54 activators: those whose assembly into ring form is controlled by two-component signal transduction. We review (i) experimental considerations of applying the SAXS (small-angle X-ray scattering)/WAXS (wide-angle X-ray scattering) technique, (ii) distinct regulation mechanisms of the AAA+ domains of three EBPs by similar two-component signal transduction receiver domains, and (iii) major conformational changes and correlated σ54-binding activity of an isolated EBP AAA+ domain in the ATP hydrolysis cycle.
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Tjalsma, Harold, Haike Antelmann, Jan D. H. Jongbloed, Peter G. Braun, Elise Darmon, Ronald Dorenbos, Jean-Yves F. Dubois, et al. "Proteomics of Protein Secretion by Bacillus subtilis: Separating the “Secrets” of the Secretome." Microbiology and Molecular Biology Reviews 68, no. 2 (June 2004): 207–33. http://dx.doi.org/10.1128/mmbr.68.2.207-233.2004.
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SUMMARY Secretory proteins perform a variety of important“ remote-control” functions for bacterial survival in the environment. The availability of complete genome sequences has allowed us to make predictions about the composition of bacterial machinery for protein secretion as well as the extracellular complement of bacterial proteomes. Recently, the power of proteomics was successfully employed to evaluate genome-based models of these so-called secretomes. Progress in this field is well illustrated by the proteomic analysis of protein secretion by the gram-positive bacterium Bacillus subtilis, for which ∼90 extracellular proteins were identified. Analysis of these proteins disclosed various“ secrets of the secretome,” such as the residence of cytoplasmic and predicted cell envelope proteins in the extracellular proteome. This showed that genome-based predictions reflect only∼ 50% of the actual composition of the extracellular proteome of B. subtilis. Importantly, proteomics allowed the first verification of the impact of individual secretion machinery components on the total flow of proteins from the cytoplasm to the extracellular environment. In conclusion, proteomics has yielded a variety of novel leads for the analysis of protein traffic in B. subtilis and other gram-positive bacteria. Ultimately, such leads will serve to increase our understanding of virulence factor biogenesis in gram-positive pathogens, which is likely to be of high medical relevance.
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Billack, Blase, Diane E. Heck, Thomas M. Mariano, Carol R. Gardner, Runa Sur, Debra L. Laskin, and Jeffrey D. Laskin. "Induction of cyclooxygenase-2 by heat shock protein 60 in macrophages and endothelial cells." American Journal of Physiology-Cell Physiology 283, no. 4 (October 1, 2002): C1267—C1277. http://dx.doi.org/10.1152/ajpcell.00609.2001.
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The 60-kDa heat shock protein (HSP60), an endogenous ligand for the toll-like 4 receptor, is generated in response to inflammation, tissue injury, and/or stress and stimulates macrophages to produce cytotoxic and proinflammatory mediators including nitric oxide, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-12. In the present studies we report that HSP60 is an effective inducer of cyclooxygenase-2 (COX-2) in macrophages, as well as endothelial cells. In both cell types, the synthesis of COX-2 was coordinate with induction of nitric oxide synthase (NOS)-2 and with nitric oxide production. With the use of promoter constructs in transient transfection assays, optimal expression of COX-2 in macrophages was found to require nuclear factor (NF)-κB, the cAMP-response element (CRE), and NF-IL-6, but not the E-box. Mobility shift assays revealed that HSP60 induced NF-κB and CRE binding activity, while CCAAT/enhancer binding protein (C/EBP), which binds to NF-IL-6, was constitutively active in the cells. Both c-Jun and CRE binding protein (CREB) bound to the CRE, while C/EBP-β bound to NF-IL-6. These data indicate that NF-κB, C/EBP-β, c-Jun, and CREB are important in HSP60-induced expression of COX-2. The c-Jun-NH2-terminal kinase (JNK), p44/42 mitogen-activated protein (MAP) kinase [extracellular signal-regulated kinase 1/2 (ERK1/2)], and p38 MAP kinase were rapidly activated by HSP60 in the macrophages. PD-98059, an inhibitor of phosphorylation of ERK1/2, caused a marked inhibition of HSP60-induced COX-2 and NOS-2 expression. Unexpectedly, SB-203580, a p38 kinase antagonist, was found to block HSP60-induced expression of COX-2, but not NOS-2. These data indicate that both ERK1/2 kinase and p38 kinase play a role in regulating HSP60-induced expression of COX-2.
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Burgess-Beusse, Bonnie L., and Gretchen J. Darlington. "C/EBPα Is Critical for the Neonatal Acute-Phase Response to Inflammation." Molecular and Cellular Biology 18, no. 12 (December 1, 1998): 7269–77. http://dx.doi.org/10.1128/mcb.18.12.7269.
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ABSTRACT Members of the C/EBP (CCAAT/enhancer binding protein) family of transcription factors play important roles in mediating the acute-phase response (APR), an inflammatory process resulting from infection and/or tissue damage. Among the C/EBP family of proteins, C/EBPβ and -δ were thought to be the primary mediators of the APR. The function of C/EBPα in the APR has not been fully characterized to date. Here, we investigate the role of C/EBPα in the APR by using neonatal mice that lack C/EBPα expression. Northern blot analysis of acute-phase protein gene expression in neonatal mice treated with purified bacterial lipopolysaccharide or recombinant interleukin 1β as an inflammation stimulus showed a strong APR in wild-type mice, but a response in C/EBPα null animals was completely lacking. The C/EBPα knockout and wild-type mice demonstrated elevations in C/EBPβ and -δ mRNA expression and DNA binding as well as increased DNA binding of NF-κB, all of which are known to be important in the APR. Null mice, however, failed to activate STAT3 binding in response to lipopolysaccharide. Our results provide the first evidence that C/EBPα is absolutely required for the APR in neonatal mice, is involved in STAT3 regulation, and cannot be compensated for by other C/EBP family members.
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Forrest, Suzanne, and Martin Welch. "Arming the troops: Post-translational modification of extracellular bacterial proteins." Science Progress 103, no. 4 (October 2020): 003685042096431. http://dx.doi.org/10.1177/0036850420964317.
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Protein secretion is almost universally employed by bacteria. Some proteins are retained on the cell surface, whereas others are released into the extracellular milieu, often playing a key role in virulence. In this review, we discuss the diverse types and potential functions of post-translational modifications (PTMs) occurring to extracellular bacterial proteins.
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Luo, Haiwei. "Predicted Protein Subcellular Localization in Dominant Surface Ocean Bacterioplankton." Applied and Environmental Microbiology 78, no. 18 (July 6, 2012): 6550–57. http://dx.doi.org/10.1128/aem.01406-12.
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ABSTRACTBacteria consume dissolved organic matter (DOM) through hydrolysis, transport and intracellular metabolism, and these activities occur in distinct subcellular localizations. Bacterial protein subcellular localizations for several major marine bacterial groups were predicted using genomic, metagenomic and metatranscriptomic data sets following modification of MetaP software for use with partial gene sequences. The most distinct pattern of subcellular localization was found forBacteroidetes, whose genomes were substantially enriched with outer membrane and extracellular proteins but depleted of inner membrane proteins compared with five other taxa (SAR11, Roseobacter,Synechococcus,Prochlorococcus, oligotrophic marineGammaproteobacteria). When subcellular localization patterns were compared between genes and transcripts, three taxa had expression biased toward proteins localized to cell locations outside of the cytosol (SAR11, Roseobacter, andSynechococcus), as expected based on the importance of carbon and nutrient acquisition in an oligotrophic ocean, but two taxa did not (oligotrophic marineGammaproteobacteriaandBacteroidetes). Diel variations in the fraction and putative gene functions of transcripts encoding inner membrane and periplasmic proteins compared to cytoplasmic proteins suggest a close coupling of photosynthetic extracellular release and bacterial consumption, providing insights into interactions between phytoplankton, bacteria, and DOM.
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GREGOIRE, FRANCINE M., CYNTHIA M. SMAS, and HEI SOOK SUL. "Understanding Adipocyte Differentiation." Physiological Reviews 78, no. 3 (January 7, 1998): 783–809. http://dx.doi.org/10.1152/physrev.1998.78.3.783.
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Gregoire, Francine M., Cynthia M. Smas, and Hei Sook Sul. Understanding Adipocyte Differentiation. Physiol. Rev. 78: 783–809, 1998. — The adipocyte plays a critical role in energy balance. Adipose tissue growth involves an increase in adipocyte size and the formation of new adipocytes from precursor cells. For the last 20 years, the cellular and molecular mechanisms of adipocyte differentiation have been extensively studied using preadipocyte culture systems. Committed preadipocytes undergo growth arrest and subsequent terminal differentiation into adipocytes. This is accompanied by a dramatic increase in expression of adipocyte genes including adipocyte fatty acid binding protein and lipid-metabolizing enzymes. Characterization of regulatory regions of adipose-specific genes has led to the identification of the transcription factors peroxisome proliferator-activated receptor-γ (PPAR-γ) and CCAAT/enhancer binding protein (C/EBP), which play a key role in the complex transcriptional cascade during adipocyte differentiation. Growth and differentiation of preadipocytes is controlled by communication between individual cells or between cells and the extracellular environment. Various hormones and growth factors that affect adipocyte differentiation in a positive or negative manner have been identified. In addition, components involved in cell-cell or cell-matrix interactions such as preadipocyte factor-1 and extracellular matrix proteins are also pivotal in regulating the differentiation process. Identification of these molecules has yielded clues to the biochemical pathways that ultimately result in transcriptional activation via PPAR-γ and C/EBP. Studies on the regulation of the these transcription factors and the mode of action of various agents that influence adipocyte differentiation will reveal the physiological and pathophysiological mechanisms underlying adipose tissue development.
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Lu, Hong, Jeng Yih Wu, Takahiko Kudo, Tomoyuki Ohno, David Y. Graham, and Yoshio Yamaoka. "Regulation of Interleukin-6 Promoter Activation in Gastric Epithelial Cells Infected withHelicobacter pylori." Molecular Biology of the Cell 16, no. 10 (October 2005): 4954–66. http://dx.doi.org/10.1091/mbc.e05-05-0426.
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The regulation of Helicobacter pylori induced interleukin (IL)-6 in the gastric epithelium remains unclear. Primary gastric epithelial cells and MKN28 cells were cocultured with H. pylori and its isogenic cag pathogenicity island (PAI) mutant and/or oipA mutants. H. pylori infection-induced IL-6 mRNA expression and IL-6 protein production, which was further enhanced by the cag PAI and OipA. Luciferase reporter gene assays and electrophoretic mobility shift assays showed that full IL-6 transcription required binding sites for nuclear factor-κB (NF-κB), cAMP response element (CRE), CCAAT/enhancer binding protein (C/EBP), and activator protein (AP)-1. The cag PAI and OipA were involved in binding to NF-κB, AP-1, CRE, and C/EBP sites. The cag PAI activated the extracellular signal-regulated kinase (ERK) and Jun N-terminal kinase (JNK) pathways; OipA activated the p38 pathway. Transfection of dominant negative G-protein confirmed roles for Raf, Rac1, and RhoA in IL-6 induction. Overall, the cag PAI-related IL-6 signal transduction pathway involved the Ras/Raf/MEK1/2/ERK/AP-1/CRE pathway and the JNK/AP-1/CRE pathway; the OipA-related pathway is p38/AP-1/CRE and both the cag PAI and OipA appear to be involved in the RhoA/Rac1/NF-κB pathway. Combination of different pathways by the cag PAI and OipA will lead to the maximum IL-6 induction.
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Orhan-Yanıkan, Esin, Gülcihan Gülseren, and Kamuran Ayhan. "Protein profile of bacterial extracellular polymeric substance by Fourier transform infrared spectroscopy." Microchemical Journal 156 (July 2020): 104831. http://dx.doi.org/10.1016/j.microc.2020.104831.
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Jones, Robert T., Maria Sanchez-Contreras, Isabella Vlisidou, Matthew R. Amos, Guowei Yang, Xavier Munoz-Berbel, Abhishek Upadhyay, et al. "Photorhabdus adhesion modification protein (Pam) binds extracellular polysaccharide and alters bacterial attachment." BMC Microbiology 10, no. 1 (2010): 141. http://dx.doi.org/10.1186/1471-2180-10-141.
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Denecke, M. "Protein extraction from activated sludge." Water Science and Technology 54, no. 1 (July 1, 2006): 175–81. http://dx.doi.org/10.2166/wst.2006.385.
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Two methods for the separation of protein originating from activated sludge were compared. In one method, the total protein was isolated out of the activated sludge (crude extract). These samples included all dissolved proteins originating from the bacterial cells and biofilm made up of extracellular polymeric substances (EPS). Every time polyacrylamide gel electrophoresis (PAGE) was done, the protein bands from samples of crude extract were covered by polymeric substances including carbohydrates, uronic acids or humic compounds. Using the immunoblot technique it was possible to demonstrate the presence of the heat shock protein HSP70 in crude extracts of activated sludge. The comparison of protein fingerprints required that clear and distinct bands appear on the PAGE analysis. To this end, a procedure to separates bacterial cells from the EPS was developed. Bacterial cells were separated by incubation with EDTA and subsequent filtration. The isolated cells were directly incubated in a sample buffer.
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Buck, M., D. Bose, P. Burrows, W. Cannon, N. Joly, T. Pape, M. Rappas, J. Schumacher, S. Wigneshweraraj, and X. Zhang. "A second paradigm for gene activation in bacteria." Biochemical Society Transactions 34, no. 6 (October 25, 2006): 1067–71. http://dx.doi.org/10.1042/bst0341067.
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Control of gene expression is key to development and adaptation. Using purified transcription components from bacteria, we employ structural and functional studies in an integrative manner to elaborate a detailed description of an obligatory step, the accessing of the DNA template, in gene expression. Our work focuses on a specialized molecular machinery that utilizes ATP hydrolysis to initiate DNA opening and permits a description of how the events triggered by ATP hydrolysis within a transcriptional activator can lead to DNA opening and transcription. The bacterial EBPs (enhancer binding proteins) that belong to the AAA+ (ATPases associated with various cellular activities) protein family remodel the RNAP (RNA polymerase) holoenzyme containing the σ54 factor and convert the initial, transcriptionally silent promoter complex into a transcriptionally proficient open complex using transactions that reflect the use of ATP hydrolysis to establish different functional states of the EBP. A molecular switch within the model EBP we study [called PspF (phage shock protein F)] is evident, and functions to control the exposure of a solvent-accessible flexible loop that engages directly with the initial RNAP promoter complex. The σ54 factor then controls the conformational changes in the RNAP required to form the open promoter complex.
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Sarvamangala, H., and K. A. Natarajan. "Microbially Induced Flotation of Galena and Quartz from Pyrite." Advanced Materials Research 71-73 (May 2009): 509–12. http://dx.doi.org/10.4028/www.scientific.net/amr.71-73.509.
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Selective separation of pyrite from galena and quartz was achieved through microbiologically induced flotation in presence of Bacillus subtilis. B. subtilis functions as a depressant for pyrite while it promotes the flotation of galena and quartz. Bacterial extracellular protein (EP) was isolated and the protein profile of bacterial cells grown in presence and absence of minerals established.
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Sun, Yan, Wentao Jiang, Mingzheng Zhang, Lingjun Zhang, Yan Shen, Shengbin Huang, Mingyun Li, et al. "The Inhibitory Effects of Ficin on Streptococcus mutans Biofilm Formation." BioMed Research International 2021 (March 23, 2021): 1–11. http://dx.doi.org/10.1155/2021/6692328.
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To investigate the effects of ficin on biofilm formation of conditionally cariogenic Streptococcus mutans (S. mutans). Biomass and metabolic activity of biofilm were assessed using crystal violet assay, colony-forming unit (CFU) counting, and MTT assay. Extracellular polysaccharide (EPS) synthesis was displayed by SEM imaging, bacteria/EPS staining, and anthrone method while acid production was revealed by lactic acid assay. Growth curve and live/dead bacterial staining were conducted to monitor bacterial growth state in both planktonic and biofilm form. Total protein and extracellular proteins of S. mutans biofilm were analyzed by protein/bacterial staining and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), severally. qRT-PCR was conducted to detect acid production, acid tolerance, and biofilm formation associated genes. Crystal violet assay, CFU counting, and MTT assay showed that the suppression effect of ficin on S. mutans biofilm formation was concentration dependent. 4 mg/mL ficin had significant inhibitory effect on S. mutans biofilm formation including biomass, metabolic activity, EPS synthesis, and lactic acid production ( p < 0.05 ). The growth curves from 0 mg/mL to 4 mg/mL ficin were aligned with each other. There was no significant difference among different ficin groups in terms of live/dead bacterial staining result ( p > 0.05 ). Protein/bacterial staining outcome indicated that ficin inhibit both total protein and biofilm formation during the biofilm development. There were more relatively small molecular weight protein bands in extracellular proteins of 4 mg/mL ficin group when compared with the control. Generally, ficin could inhibit biofilm formation and reduce cariogenic virulence of S. mutans effectively in vitro; thus, it could be a potential anticaries agent.
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Liu, J. K., C. M. DiPersio, and K. S. Zaret. "Extracellular signals that regulate liver transcription factors during hepatic differentiation in vitro." Molecular and Cellular Biology 11, no. 2 (February 1991): 773–84. http://dx.doi.org/10.1128/mcb.11.2.773-784.1991.
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A complex cell culture environment has been shown to maintain the differentiated state of hepatocytes, yet the mechanisms by which environmental cues selectively maintain liver-specific gene transcription have been unknown. In this paper we show that the hepatic environment regulates the activities of at least three liver-enriched transcription factors, eE-TF, eG-TF/HNF3, and eH-TF, that activate the mouse serum albumin enhancer. eE-TF is a heat-stable factor that has a DNA-binding specificity similar to that of the liver transcription factor C/EBP, but is a distinct protein. eG-TF/HNF3 contributes to the liver-specific transcription of several other serum protein genes. eH-TF binds to a TGTTTGC sequence that occurs at regulatory sites of the albumin promoter, the hepatitis B virus enhancer, and other hepatic genes. eE-TF, eG-TF/HNF3, and eH-TF are regulated by different combinations of the following cell culture conditions: a hormonally defined serum-free medium; an extracellular matrix gel; and a transformation-competent simian virus 40 large T antigen. We propose a regulatory network model to explain how cues from the cell lineage and the extracellular environment coordinately help maintain the activities of transcription factors involved in hepatocyte differentiation.
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Liu, J. K., C. M. DiPersio, and K. S. Zaret. "Extracellular signals that regulate liver transcription factors during hepatic differentiation in vitro." Molecular and Cellular Biology 11, no. 2 (February 1991): 773–84. http://dx.doi.org/10.1128/mcb.11.2.773.
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A complex cell culture environment has been shown to maintain the differentiated state of hepatocytes, yet the mechanisms by which environmental cues selectively maintain liver-specific gene transcription have been unknown. In this paper we show that the hepatic environment regulates the activities of at least three liver-enriched transcription factors, eE-TF, eG-TF/HNF3, and eH-TF, that activate the mouse serum albumin enhancer. eE-TF is a heat-stable factor that has a DNA-binding specificity similar to that of the liver transcription factor C/EBP, but is a distinct protein. eG-TF/HNF3 contributes to the liver-specific transcription of several other serum protein genes. eH-TF binds to a TGTTTGC sequence that occurs at regulatory sites of the albumin promoter, the hepatitis B virus enhancer, and other hepatic genes. eE-TF, eG-TF/HNF3, and eH-TF are regulated by different combinations of the following cell culture conditions: a hormonally defined serum-free medium; an extracellular matrix gel; and a transformation-competent simian virus 40 large T antigen. We propose a regulatory network model to explain how cues from the cell lineage and the extracellular environment coordinately help maintain the activities of transcription factors involved in hepatocyte differentiation.
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STEINMÜLLER, Lars, Giuseppe CIBELLI, Jonathan R. MOLL, Charles VINSON, and Gerald THIEL. "Regulation and composition of activator protein 1 (AP-1) transcription factors controlling collagenase and c-Jun promoter activities." Biochemical Journal 360, no. 3 (December 10, 2001): 599–607. http://dx.doi.org/10.1042/bj3600599.
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The activator protein 1 (AP-1) transcription factor is composed of heterodimers of the Fos/activating transcription factor (ATF) and Jun subfamilies of basic-region leucine-zipper (B-ZIP) proteins. In order to determine the identities of individual B-ZIP proteins in various AP-1 complexes we tested the effect of dominant-negative mutants to the B-ZIP proteins c-Fos, ATF2, ATF4 and CCAAT-enhancer-binding protein (C/EBP) on the activities of the collagenase and c-Jun promoters. These dominant-negative mutants inhibit DNA binding of wild-type B-ZIP proteins in a leucine-zipper-dependent fashion. Transcription of a collagenase promoter/reporter gene was induced in HepG2 hepatoma cells by expression of c-Fos and c-Jun, administration of PMA (‘TPA’) or by expression of a truncated form of MEK (mitogen-activated/extracellular-signal-regulated kinase kinase) kinase-1, MEKK1Δ. In all cases, the dominant-negative mutants A-Fos and A-ATF2 decreased collagenase promoter activity. However, A-ATF4 and A-C/EBP had no effect. A-Fos and A-ATF2 also reduced MEKK1Δ-induced stimulation of the c-Jun promoter. In contrast, constitutive c-Jun promoter activity was blocked solely by A-ATF2, strongly suggesting that ATF2 and/or an ATF2-dimerizing protein are of major importance for c-Jun transcription in unstimulated cells. These results demonstrate that AP-1 transcription factors of different compositions control c-jun gene transcription in resting or stimulated cells.
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Chudzik, Anna, Paweł Migdał, and Mariola Paściak. "Different Cutibacterium acnes Phylotypes Release Distinct Extracellular Vesicles." International Journal of Molecular Sciences 23, no. 10 (May 21, 2022): 5797. http://dx.doi.org/10.3390/ijms23105797.
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Bacterial extracellular vesicles (EVs) perform various biological functions, including those that are critical to microbes. Determination of EVs composition allows for a deep understanding of their role in the bacterial community and communication among them. Cutibacterium acnes, formerly Propionibacteriumacnes, are commensal bacteria responsible for various infections, e.g., prosthesis, sarcoidosis, soft-tissue infections, and the most known but still controversial—acnes lesion. In C. acnes, three major phylotypes represented variable disease associations. Herein, for the first time, we present a comparative analysis of EVs obtained from three C. acnes phylotypes (IA1, IB, and II) to demonstrate the existence of differences in their protein and lipid composition. In the following work, the morphological analysis of EVs was performed, and the SDS-PAGE protein profile and the lipid profile were presented using the TLC and MALDI-TOF MS methods. This study allowed us to show major differences between the protein and lipid composition of C. acnes EVs. This is a clear indication that EVs released by different phylotypes of the one species are not identical to each other in terms of composition and should be separately analyzed each time to obtain reliable results.
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Nallapareddy, Sreedhar R., Kavindra V. Singh, Jouko Sillanpää, Meng Zhao, and Barbara E. Murray. "Relative Contributions of Ebp Pili and the Collagen Adhesin Ace to Host Extracellular Matrix Protein Adherence and Experimental Urinary Tract Infection by Enterococcus faecalis OG1RF." Infection and Immunity 79, no. 7 (April 19, 2011): 2901–10. http://dx.doi.org/10.1128/iai.00038-11.
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ABSTRACTPrevious studies have demonstrated that theebpoperon and theacegene ofEnterococcus faecalis, encodingendocarditis- andbiofilm-associatedpili and anadhesin tocollagen ofE. faecalis, respectively, are both important in experimental urinary tract infections (UTI) and endocarditis. We have also shown that growth ofE. faecalisin brain heart infusion (BHI) serum enhances Ebp pilus and Ace production and increases adherence to several host extracellular matrix proteins. Here, we report that deletion ofebpABCalmost eliminated serum-elicited adherence to fibrinogen (P< 0.0001), resulted in moderate reduction in adherence to collagen (P< 0.05), and had no effect on fibronectin adherence relative to that of wild-type OG1RF. An OG1RFΔaceΔebpABCdouble mutant showed further reduced collagen adherence versus that of the OG1RFΔaceor OG1RFΔebpABCmutants (P< 0.001). These results were corroborated by complementation and/or studies with native pilus-enriched surface extracts and a collagen-secreting 3T6 fibroblast cell line, as well as antibody inhibition. In the UTI model, both the OG1RFΔaceand OG1RFΔaceΔebpABCmutants were found to be significantly attenuated compared to the wild type; however, no significant differences were observed between individualaceorebpmutants and the OG1RFΔaceΔebpABCmutant. In summary, these data implicate the Ebp pili as having some role in collagen adherence, albeit less than that of Ace, and a very major role in fibrinogen adherence, which may explain in part the importance of these pili in experimental endocarditis. The OG1RFΔaceΔebpABCmutant was attenuated in the UTI model, although not significantly more so than the Δaceor ΔebpABCmutants, suggesting involvement of otherE. faecalisfactors in urinary tract colonization or infection.
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Pietrocola, Giampiero, Angelica Pellegrini, Mariangela J. Alfeo, Loredana Marchese, Timothy J. Foster, and Pietro Speziale. "The iron-regulated surface determinant B (IsdB) protein from Staphylococcus aureus acts as a receptor for the host protein vitronectin." Journal of Biological Chemistry 295, no. 29 (June 4, 2020): 10008–22. http://dx.doi.org/10.1074/jbc.ra120.013510.
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Staphylococcus aureus is an important bacterial pathogen that can cause a wide spectrum of diseases in humans and other animals. S. aureus expresses a variety of virulence factors that promote infection with this pathogen. These include cell-surface proteins that mediate adherence of the bacterial cells to host extracellular matrix components, such as fibronectin and fibrinogen. Here, using immunoblotting, ELISA, and surface plasmon resonance analysis, we report that the iron-regulated surface determinant B (IsdB) protein, besides being involved in heme transport, plays a novel role as a receptor for the plasma and extracellular matrix protein vitronectin (Vn). Vn-binding activity was expressed by staphylococcal strains grown under iron starvation conditions when Isd proteins are expressed. Recombinant IsdB bound Vn dose dependently and specifically. Both near-iron transporter motifs NEAT1 and NEAT2 of IsdB individually bound Vn in a saturable manner, with KD values in the range of 16–18 nm. Binding of Vn to IsdB was specifically blocked by heparin and reduced at high ionic strength. Furthermore, IsdB-expressing bacterial cells bound significantly higher amounts of Vn from human plasma than did an isdB mutant. Adherence to and invasion of epithelial and endothelial cells by IsdB-expressing S. aureus cells was promoted by Vn, and an αvβ3 integrin-blocking mAb or cilengitide inhibited adherence and invasion by staphylococci, suggesting that Vn acts as a bridge between IsdB and host αvβ3 integrin.
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Jones, Leandra B., Sanjay Kumar, Courtnee’ R. Bell, Brennetta J. Crenshaw, Mamie T. Coats, Brian Sims, and Qiana L. Matthews. "Lipopolysaccharide Administration Alters Extracellular Vesicles in Cell Lines and Mice." Current Microbiology 78, no. 3 (February 9, 2021): 920–31. http://dx.doi.org/10.1007/s00284-021-02348-5.
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AbstractExtracellular vesicles (EVs) play a fundamental role in cell and infection biology and have the potential to act as biomarkers for novel diagnostic tools. In this study, we explored the in vitro impact of bacterial lipopolysaccharide administration on cell lines that represents a target for bacterial infection in the host. Administration of lipopolysaccharide at varying concentrations to A549 and BV-2 cell lines caused only modest changes in cell death, but EV numbers were significantly changed. After treatment with the highest concentration of lipopolysaccharide, EVs derived from A549 cells packaged significantly less interleukin-6 and lysosomal-associated membrane protein 1. EVs derived from BV-2 cells packaged significantly less tumor necrosis factor after administration of lipopolysaccharide concentrations of 0.1 µg/mL and 1 µg/mL. We also examined the impact of lipopolysaccharide administration on exosome biogenesis and cargo composition in BALB/c mice. Serum-isolated EVs from lipopolysaccharide-treated mice showed significantly increased lysosomal-associated membrane protein 1 and toll-like receptor 4 levels compared with EVs from control mice. In summary, this study demonstrated that EV numbers and cargo were altered using these in vitro and in vivo models of bacterial infection.
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Chagnot, Caroline, Anne Listrat, Thierry Astruc, and Mickaël Desvaux. "Bacterial adhesion to animal tissues: protein determinants for recognition of extracellular matrix components." Cellular Microbiology 14, no. 11 (September 3, 2012): 1687–96. http://dx.doi.org/10.1111/cmi.12002.
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Dominiecki, Mary E., and Jerrold Weiss. "Antibacterial Action of Extracellular Mammalian Group IIA Phospholipase A2 against Grossly ClumpedStaphylococcus aureus." Infection and Immunity 67, no. 5 (May 1, 1999): 2299–305. http://dx.doi.org/10.1128/iai.67.5.2299-2305.1999.
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ABSTRACT Fibrinogen-dependent interactions of Staphylococcus aureus are believed to contribute to bacterial virulence by promoting bacterial attachment to fibrinogen-coated surfaces and inducing the formation of bacterial clumps that are likely resistant to phagocytosis. Although S. aureus produces several fibrinogen-binding proteins, the cell wall-associated protein clumping factor (encoded by clfA) appears to be most important in bacterial interactions with immobilized or soluble purified fibrinogen. We have compared bacterial clumping in several strains of S. aureus, including isogenic ClfA+ and ClfA− Newman strains, in the presence of purified rabbit fibrinogen, human plasma, and inflammatory fluid and examined the effect of clumping on bacterial sensitivity to mammalian group IIA phospholipase A2 (PLA2). This enzyme is the major extracellular bactericidal agent in inflammatory fluid active against S. aureus. Both ClfA-dependent and ClfA-independent bacterial clumping was observed, depending on the source and fibrinogen content of the biological fluid. In each case, clumping only partially reduced the antibacterial activity of PLA2, suggesting that this extracellular enzyme can substantially penetrate dense bacterial clumps. Bacterial clumps could be dispersed by added proteases, restoring full antibacterial activity to PLA2. Thus, the extracellular mobilization of group IIA PLA2 during inflammation may provide a mechanism by which the host can control the proliferation and survival of S. aureus even after bacterial clumping.
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He, Nan, Juan Zhou, Miyun Hu, Changyang Ma, and Wenyi Kang. "The mechanism of antibacterial activity of corylifolinin against three clinical bacteria from Psoralen corylifolia L." Open Chemistry 16, no. 1 (September 3, 2018): 882–89. http://dx.doi.org/10.1515/chem-2018-0091.
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AbstractEffective antibacterial activity against Grampositive bacteria isolated in clinical strains was exhibited when corylifolinin was tested using the Disc diffusion method (K-B method). Minimum inhibitory concentration (MIC) of corylifolinin against Staphylococcus aureus (SA), Methcillin-resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamases Staphylococcus aureus (ESBLs-SA) were 0.078, 0.156 and 0.078 mg/mL, respectively. The minimum bactericide concentrations (MBCs) were 0.156, 0.156 and 0.078 mg/mL respectively. Scanning electron microscopy (SEM), alkaline phosphatase (AKP) and bacterial extracellular protein leakage were used to investigate the antibacterial mechanism of corylifolinin. After adding corylifolinin at the MBC level, there were obvious changes to the Staphylococcus aureus of bacteria cells. Both MIC level and MBC levels of corylifolinin led to the leakage of AKP and bacterial extracellular protein.
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Lee, Jaewook, Eun-Young Lee, Si-Hyun Kim, Dae-Kyum Kim, Kyong-Su Park, Kwang Pyo Kim, Yoon-Keun Kim, Tae-Young Roh, and Yong Song Gho. "Staphylococcus aureus Extracellular Vesicles Carry Biologically Active β-Lactamase." Antimicrobial Agents and Chemotherapy 57, no. 6 (March 25, 2013): 2589–95. http://dx.doi.org/10.1128/aac.00522-12.
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ABSTRACTGram-positive bacteria naturally produce extracellular vesicles. However, little is known regarding the functions of Gram-positive bacterial extracellular vesicles, especially in the bacterial community. Here, we investigated the role ofStaphylococcus aureusextracellular vesicles in interbacterial communication to cope with antibiotic stress. We found thatS. aureusliberated BlaZ, a β-lactamase protein, via extracellular vesicles. These extracellular vesicles enabled other ampicillin-susceptible Gram-negative and Gram-positive bacteria to survive in the presence of ampicillin. However,S. aureusextracellular vesicles did not mediate the survival of tetracycline-, chloramphenicol-, or kanamycin-susceptible bacteria. Moreover,S. aureusextracellular vesicles did not contain theblaZgene. In addition, the heat-treatedS. aureusextracellular vesicles did not mediate the survival of ampicillin-susceptible bacteria. The β-lactamase activities ofS. aureussoluble and extracellular vesicle-associated BlaZ were similar, but only the extracellular vesicle-associated BlaZ was resistant to protease digestion, which suggests that the enzymatic activity of BlaZ in extracellular vesicles is largely protected by the vesicle structure. Our observations provide evidence of the important role ofS. aureusextracellular vesicles in antibiotic resistance, which allows the polymicrobial community to continue to evolve and prosper against antibiotics.
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Yu, Chao, Fenghuan Yang, Dingrong Xue, Xiuna Wang, and Huamin Chen. "The Regulatory Functions of σ54 Factor in Phytopathogenic Bacteria." International Journal of Molecular Sciences 22, no. 23 (November 24, 2021): 12692. http://dx.doi.org/10.3390/ijms222312692.
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σ54 factor (RpoN), a type of transcriptional regulatory factor, is widely found in pathogenic bacteria. It binds to core RNA polymerase (RNAP) and regulates the transcription of many functional genes in an enhancer-binding protein (EBP)-dependent manner. σ54 has two conserved functional domains: the activator-interacting domain located at the N-terminal and the DNA-binding domain located at the C-terminal. RpoN directly binds to the highly conserved sequence, GGN10GC, at the −24/−12 position relative to the transcription start site of target genes. In general, bacteria contain one or two RpoNs but multiple EBPs. A single RpoN can bind to different EBPs in order to regulate various biological functions. Thus, the overlapping and unique regulatory pathways of two RpoNs and multiple EBP-dependent regulatory pathways form a complex regulatory network in bacteria. However, the regulatory role of RpoN and EBPs is still poorly understood in phytopathogenic bacteria, which cause economically important crop diseases and pose a serious threat to world food security. In this review, we summarize the current knowledge on the regulatory function of RpoN, including swimming motility, flagella synthesis, bacterial growth, type IV pilus (T4Ps), twitching motility, type III secretion system (T3SS), and virulence-associated phenotypes in phytopathogenic bacteria. These findings and knowledge prove the key regulatory role of RpoN in bacterial growth and pathogenesis, as well as lay the groundwork for further elucidation of the complex regulatory network of RpoN in bacteria.
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Barker, William W., and Vernon J. Hurst. "Freeze etch replication of extracellular bacterial polymers adsorbed onto kaolinite." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 52–53. http://dx.doi.org/10.1017/s0424820100146102.
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Freeze etch replication of experimental mixtures of euhedral kaolinite and pure cultures of polysaccharide and protein-producing bacteria reveals that surface textures formed by adsorption of extracellular bacterial polymers onto kaolinite surfaces resemble structures observed in natural estuarine clay rich sediments, where anhedral 0.1 micrometer clay surfaces are covered by anhedral masses and fibrous elements of organic material.All samples, were cryofixed in a Balzers QFD101 propane jet and replicated in a Balzers 360M freeze etch device. Etching occurred at −100°C for 45 sec. and replicas were created with 15 nm Pt @ 45 °, 15 sec. C @ 90°. Following 24 h digestion in cone. HF, replicas were mounted on Formvar-coated 100 mesh Cu grids, carbon-coated for thermal stability, and examined in a Philips STEM 400.Anionic mucopolysaccharide produced by pure cultures of encapsulated Klebsiella pneumoniae (ATCC 8044) readily adsorbed to both the basal (negative charge) and edge (positive charge) surfaces of kaolinite (Fig. 1).
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Nandi, Ipsita, and Benjamin Aroeti. "Mitogen-Activated Protein Kinases (MAPKs) and Enteric Bacterial Pathogens: A Complex Interplay." International Journal of Molecular Sciences 24, no. 15 (July 25, 2023): 11905. http://dx.doi.org/10.3390/ijms241511905.
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Diverse extracellular and intracellular cues activate mammalian mitogen-activated protein kinases (MAPKs). Canonically, the activation starts at cell surface receptors and continues via intracellular MAPK components, acting in the host cell nucleus as activators of transcriptional programs to regulate various cellular activities, including proinflammatory responses against bacterial pathogens. For instance, binding host pattern recognition receptors (PRRs) on the surface of intestinal epithelial cells to bacterial pathogen external components trigger the MAPK/NF-κB signaling cascade, eliciting cytokine production. This results in an innate immune response that can eliminate the bacterial pathogen. However, enteric bacterial pathogens evolved sophisticated mechanisms that interfere with such a response by delivering virulent proteins, termed effectors, and toxins into the host cells. These proteins act in numerous ways to inactivate or activate critical components of the MAPK signaling cascades and innate immunity. The consequence of such activities could lead to successful bacterial colonization, dissemination, and pathogenicity. This article will review enteric bacterial pathogens’ strategies to modulate MAPKs and host responses. It will also discuss findings attempting to develop anti-microbial treatments by targeting MAPKs.