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  • 1
    In: PLoS ONE, 2015, Vol.10(2)
    Description: Given the emerging evidence of an association between periodontal infections and systemic conditions, the search for specific methods to detect the presence of P. gingivalis , a principal etiologic agent in chronic periodontitis, is of high importance. The aim of this study was to characterize antibodies raised against purified P. gingivalis HmuY protein and selected epitopes of the HmuY molecule. Since other periodontopathogens produce homologs of HmuY, we also aimed to characterize responses of antibodies raised against the HmuY protein or its epitopes to the closest homologous proteins from Prevotella intermedia and Tannerella forsythia . Rabbits were immunized with purified HmuY protein or three synthetic, KLH-conjugated peptides, derived from the P. gingivalis HmuY protein. The reactivity of anti-HmuY antibodies with purified proteins or bacteria was determined using Western blotting and ELISA assay. First, we found homologs of P. gingivalis HmuY in P. intermedia (PinO and PinA proteins) and T. forsythia (Tfo protein) and identified corrected nucleotide and amino acid sequences of Tfo. All proteins were overexpressed in E. coli and purified using ion-exchange chromatography, hydrophobic chromatography and gel filtration. We demonstrated that antibodies raised against P. gingivalis HmuY are highly specific to purified HmuY protein and HmuY attached to P. gingivalis cells. No reactivity between P. intermedia and T. forsythia or between purified HmuY homologs from these bacteria and anti-HmuY antibodies was detected. The results obtained in this study demonstrate that P. gingivalis HmuY protein may serve as an antigen for specific determination of serum antibodies raised against this bacterium.
    Keywords: Research Article
    E-ISSN: 1932-6203
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  • 2
    Language: English
    In: Anaerobe, April 2017, Vol.44, pp.27-33
    Description: is a major etiologic agent and a key pathogen responsible for the development and progression of chronic periodontitis. Controlling the number of periodontal pathogens is one of the primary actions for maintaining oral health; therefore, active compounds with a capacity to exert antimicrobial activity have received considerable attention as they may represent potential new therapeutic agents for the treatment of chronic periodontitis. Heterocyclic compounds possessing 1,2,4- or 1,2,3-triazoles are known for several biological activities, including antibacterial properties. Among them are stable hemiaminals which can be obtained in reaction between nitrobenzaldehyde derivatives and 4-amino-1,2,4-triazole or 4-amino-3,5-dimethyl-1,2,4-triazole. In this study, we selected two relatively stable hemiaminals: (2,4-dinitrophenyl)(4 -1,2,4-triazole-4-ylamino)methanol (24DNTAM) and (2,4-dinitrophenyl)(4 -3,5-dimethyl-1,2,4-triazole-4-ylamino)methanol (24DNDMTAM). Both compounds showed promising anti- activity, higher against ATCC 33277 strain as compared to A7436 strain. The lowest hemiaminal concentration inhibiting visible planktonic bacterial growth under high-iron/heme conditions was ∼0.06 mg/ml, and the lowest hemiaminal concentration showing killing of bacteria was ∼0.25 mg/ml. Antimicrobial activity was also observed against grown on blood agar plates. Slightly higher antimicrobial activity of both compounds was observed when was grown in co-cultures with epithelial HeLa cells under low-iron/heme conditions, which mimic those occurring . 24DNTAM was more effective against , but exhibited higher cytotoxic activity against epithelial and red blood cells, as compared with 24DNDMTAM. We conclude that both hemiaminals might originate a novel group of biologically important molecules.
    Keywords: Porphyromonas Gingivalis ; Hemiaminal ; Antimicrobial Activity ; Biology
    ISSN: 1075-9964
    E-ISSN: 1095-8274
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  • 3
    Language: English
    In: Bioscience reports, 31 October 2018, Vol.38(5)
    Description: is considered the principal etiologic agent and keystone pathogen of chronic periodontitis. As an auxotrophic bacterium, it must acquire heme to survive and multiply at the infection site. HmuY is the first member of a novel family of hemophore-like proteins. Bacterial heme-binding proteins usually use histidine-methionine or histidine-tyrosine residues to ligate heme-iron, whereas HmuY uses two histidine residues. We hypothesized that other 'red complex' members, i.e. and might utilize similar heme uptake mechanisms to the HmuY. Comparative and phylogenetic analyses suggested differentiation of HmuY homologs and low conservation of heme-coordinating histidine residues present in HmuY. The homologs were subjected to duplication before divergence of lineages, which could facilitate evolution of functional diversification. We found that does not code an HmuY homolog. protein, termed as Tfo, binds heme, but preferentially in the ferrous form, and sequesters heme from the albumin-heme complex under reducing conditions. In agreement with that, the 3D structure of Tfo differs from that of HmuY in the folding of heme-binding pocket, containing two methionine residues instead of two histidine residues coordinating heme in HmuY. Heme binding to apo-HmuY is accompanied by movement of the loop carrying the His residue, closing the heme-binding pocket. Molecular dynamics simulations (MD) demonstrated that this conformational change also occurs in Tfo. In conclusion, our findings suggest that HmuY-like family might comprise proteins subjected during evolution to significant diversification, resulting in different heme-binding properties.
    Keywords: Hmuy ; Porphyromonas Gingivalis ; Tannerella Forsythia ; Tfo ; Heme ; Periodontitis ; Carrier Proteins -- Chemistry ; Chronic Periodontitis -- Genetics ; Hemeproteins -- Chemistry ; Porphyromonas Gingivalis -- Chemistry ; Tannerella Forsythia -- Chemistry
    ISSN: 01448463
    E-ISSN: 1573-4935
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  • 4
    Language: English
    Description: Understanding RNA processing and turnover requires knowledge of cleavages by major endoribonucleases within a living cell. We have employed TIER-seq (transiently inactivating an endoribonuclease followed by RNA-seq) to profile cleavage products of the essential endoribonuclease RNase E in Salmonella enterica. A dominating cleavage signature is the location of a uridine two nucleotides downstream in a single-stranded segment, which we rationalize structurally as a key recognition determinant that may favor RNase E catalysis. Our results suggest a prominent biogenesis pathway for bacterial regulatory small RNAs whereby RNase E acts together with the RNA chaperone Hfq to liberate stable 3′ fragments from various precursor RNAs. Recapitulating this process in vitro, Hfq guides RNase E cleavage of a representative small-RNA precursor for interaction with a mRNA target. In vivo, the processing is required for target regulation. Our findings reveal a general maturation mechanism for a major class of post-transcriptional regulators.
    Description: This study was funded by DFG ( Vo875/14-1 ) and BioSysNet grants. B.F.L. is supported by the Wellcome Trust. K.P. was supported by the Human Frontiers Science Program (CDA00024/2016-C) .
    Source: DSpace@Cambridge
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  • 5
    Language: English
    In: Molecular Cell, 05 January 2017, Vol.65(1), pp.39-51
    Description: Understanding RNA processing and turnover requires knowledge of cleavages by major endoribonucleases within a living cell. We have employed TIER-seq (transiently inactivating an endoribonuclease followed by RNA-seq) to profile cleavage products of the essential endoribonuclease RNase E in . A dominating cleavage signature is the location of a uridine two nucleotides downstream in a single-stranded segment, which we rationalize structurally as a key recognition determinant that may favor RNase E catalysis. Our results suggest a prominent biogenesis pathway for bacterial regulatory small RNAs whereby RNase E acts together with the RNA chaperone Hfq to liberate stable 3′ fragments from various precursor RNAs. Recapitulating this process in vitro, Hfq guides RNase E cleavage of a representative small-RNA precursor for interaction with a mRNA target. In vivo, the processing is required for target regulation. Our findings reveal a general maturation mechanism for a major class of post-transcriptional regulators. Chao et al. discover that the essential bacterial RNase E cleaves numerous transcripts at preferred sites by sensing uridine as a 2-nt ruler. RNase E processing of various precursor RNAs produces many small regulatory RNAs, constituting a major small-RNA biogenesis pathway in bacteria.
    Keywords: Rnase E ; RNA Degradome ; Non-Coding RNA ; Hfq ; 3′ Utr ; Arcz ; Rpra ; Srna Maturation ; Uridine Ruler ; Tier-Seq ; Biology
    ISSN: 1097-2765
    E-ISSN: 1097-4164
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  • 6
    Description: Understanding RNA processing and turnover requires knowledge of cleavages by major endoribonucleases within a living cell. We have employed TIER-seq (transiently inactivating an endoribonuclease followed by RNA-seq) to profile cleavage products of the essential endoribonuclease RNase E in Salmonella enterica. A dominating cleavage signature is the location of a uridine two nucleotides downstream in a single-stranded segment, which we rationalize structurally as a key recognition determinant that may favor RNase E catalysis. Our results suggest a prominent biogenesis pathway for bacterial regulatory small RNAs whereby RNase E acts together with the RNA chaperone Hfq to liberate stable 3′ fragments from various precursor RNAs. Recapitulating this process in vitro, Hfq guides RNase E cleavage of a representative small-RNA precursor for interaction with a mRNA target. In vivo, the processing is required for target regulation. Our findings reveal a general maturation mechanism for a major class of post-transcriptional regulators....
    ISSN: 1097-2765
    Source: DataCite
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  • 7
    Language: English
    Description: Understanding RNA processing and turnover requires knowledge of cleavages by major endoribonucleases within a living cell. We have employed TIER-seq (transiently inactivating an endoribonuclease followed by RNA-seq) to profile cleavage products of the essential endoribonuclease RNase E in Salmonella enterica. A dominating cleavage signature is the location of a uridine two nucleotides downstream in a single-stranded segment, which we rationalize structurally as a key recognition determinant that may favor RNase E catalysis. Our results suggest a prominent biogenesis pathway for bacterial regulatory small RNAs whereby RNase E acts together with the RNA chaperone Hfq to liberate stable 30 fragments from various precursor RNAs. Recapitulating this process in vitro, Hfq guides RNase E cleavage of a representative small-RNA precursor for interaction with a mRNA target. In vivo, the processing is required for target regulation. Our findings reveal a general maturation mechanism for a major class of post-transcriptional regulators.
    Source: Open Access LMU (Universitätsbibliothek der LMU München)
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  • 8
    Language: English
    In: BMC Microbiology, 01 June 2019, Vol.19(1), pp.1-16
    Description: Abstract Background Porphyromonas gingivalis is considered a keystone pathogen responsible for chronic periodontitis. Although several virulence factors produced by this bacterium are quite well characterized, very little is known about regulatory mechanisms that allow different strains of...
    Keywords: Porphyromonas Gingivalis ; Ferric Uptake Regulator ; Pgfur ; Iron ; Heme ; Virulence ; Biology
    E-ISSN: 1471-2180
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  • 9
    Language: English
    In: Frontiers in cellular and infection microbiology, 2019, Vol.9, pp.233
    Description: , a keystone pathogen of chronic periodontitis, uses ferric uptake regulator homolog (PgFur) to regulate production of virulence factors. This study aimed to characterize PgFur protein in regard to its structure-function relationship. We experimentally identified the 5' mRNA sequence encoding the 171-amino-acid-long PgFur protein in the A7436 strain and examined this PgFur version as a full-length protein. PgFur protein did not bind to the canonical Fur box, but the wild-type phenotype of the mutant Δ strain was restored partially when expression of the gene was induced from the native promoter. The full-length PgFur protein contained one zinc atom per protein monomer, but did not bind iron, manganese, or heme. Single cysteine substitutions of CXXC motifs resulted in phenotypes similar to the mutant Δ strain. The modified proteins were produced in at significantly lower levels, were highly unstable, and did not bind zinc. The gene was expressed at the highest levels in bacteria cultured for 24 h in the absence of iron and heme or at higher levels in bacteria cultured for 10 h in the presence of protoporphyrin IX source. No influence of high availability of Fe, Zn, or Mn on gene expression was observed. Two chromosomal mutant strains producing protein lacking 4 (Δ) or 13 (Δ) C-terminal amino acid residues were examined in regard to importance of the C-terminal lysine-rich region. The Δ strain showed a phenotype typical for the mutant Δ strain, but both the wild-type PgFur protein and its truncated version bound zinc with similar ability. The Δ mutant strain produced higher amounts of HmuY protein compared with the wild-type strain, suggesting compromised regulation of its expression. Potential PgFur ligands, Fe, Mn, Zn, PPIX, or serum components, did not influence HmuY production in the Δ mutant strain. The mutant Δ and Δ strains exhibited affected HmuY protein production. PgFur, regardless of the presence of the C-terminal lysine-rich region, bound to the operon promoter. Our data suggest that cooperation of PgFur with partners/cofactors and/or protein/DNA modifications would be required to accomplish its role played in an multilayer regulatory network.
    Keywords: Hmuy ; Pgfur ; Porphyromonas Gingivalis ; Ferric Uptake Regulation Protein (Fur) ; Periodontitis ; Transcription Regulation
    E-ISSN: 2235-2988
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  • 10
    Language: English
    In: European Polymer Journal, 2008, Vol.44(11), pp.3556-3563
    Description: The comparative studies on the anionic polymerization of β-butyrolactone (BL) initiated with various salts of acetic acid have revealed strong sensitivity of the reaction rate on solvent polarity (benzene, THF, DMSO) and size of counterion. It was found that the polymerization rate in THF depends on the size of counterion and the type of macrocyclic ligand; it decreases in the following order: K /Kryptofix® 222 ≈TBA 〉 K /18C6 〉 Na /18C6 〉 Na /15C5 〉 K . It was also shown that the anionic polymerization of BL initiated with carboxylic acid salts depends strongly on the solvent polarity. In the polymerization initiated by acetate anions with a large counterion, the high-polar solvent as DMSO affects unfavorably the reaction rate, however, when a small counterion is applied, the opposite tendency is observed.
    Keywords: Anionic Polymerization ; Β-Butyrolactone ; Solvent Effect ; Counterion Effect ; Kinetics ; Chemistry
    ISSN: 0014-3057
    E-ISSN: 1873-1945
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