scholarly journals NamZ1 and NamZ2 from the oral pathogen Tannerella forsythia are peptidoglycan processing exo-β-N-acetylmuramidases with distinct substrate specificity

2021 ◽  
Author(s):  
Marina Borisova ◽  
Katja Balbuchta ◽  
Andrew Lovering ◽  
Alexander Titz ◽  
Christoph Mayer
Keyword(s):  
Cell Wall ◽  
Oral Microbiome ◽  
Periodontal Pathogen ◽  
Nutrient Source ◽  
Tannerella Forsythia ◽  
Substrate Specificities ◽  
Naturally Occurring ◽  
Essential Growth ◽  
Essential Growth Factor ◽  
Broad Scale

ABSTRACTThe Gram-negative periodontal pathogen Tannerella forsythia is inherently auxotrophic for N-acetylmuramic acid (MurNAc), which is an essential carbohydrate constituent of the peptidoglycan (PGN) of the bacterial cell wall. Thus, to build up its cell wall, T. forsythia strictly depends on the salvage of exogenous MurNAc or sources of MurNAc, such as polymeric or fragmentary PGN, derived from cohabiting bacteria within the oral microbiome. In our effort to elucidate how T. forsythia satisfies its demand for MurNAc, we recognized that the organism possesses three putative orthologs of the exo-β-N-acetylmuramidase BsNamZ from Bacillus subtilis, which cleaves non-reducing end, terminal MurNAc entities from the artificial substrate pNP-MurNAc and the naturally-occurring disaccharide substrate MurNAc-β-1,4-N-acetylglucosamine (GlcNAc). TfNamZ1 and TfNamZ2 were successfully purified as soluble, pure recombinant His6-fusions and characterized as exo-lytic β-N-acetylmuramidases with distinct substrate specificities. The activity of TfNamZ1 was considerably lower compared to TfNamZ2 and BsNamZ, in the cleavage of pNP-MurNAc and MurNAc-GlcNAc. When peptide-free PGN glycans were used as substrates, we revealed striking differences in the specificity and mode of action of these enzymes, as analyzed by mass spectrometry. TfNamZ1, but not TfNamZ2 or BsNamZ, released GlcNAc-MurNAc disaccharides from these glycans. In addition, glucosamine (GlcN)-MurNAc disaccharides were generated when partially N-deacetylated PGN glycans from B. subtilis 168 were applied. This characterizes TfNamZ1 as a unique disaccharide-forming exo-lytic β-N-acetylmuramidase (exo-disaccharidase), and, TfNamZ2 and BsNamZ as sole MurNAc monosaccharide-lytic exo-β-N-acetylmuramidases.IMPORTANCETwo exo-β-N-acetylmuramidases from T. forsythia belonging to glycosidase family GH171 (www.cazy.org) were shown to differ in their activities, thus revealing a functional diversity within this family: NamZ1 releases disaccharides (GlcNAc-MurNAc/GlcN-MurNAc) from the non-reducing ends of PGN glycans, whereas NamZ2 releases terminal MurNAc monosaccharides. This work provides a better understanding of how T. forsythia may acquire the essential growth factor MurNAc by the salvage of PGN from cohabiting bacteria in the oral microbiome, which may pave avenues for the development of anti-periodontal drugs. On a broad scale, our study indicates that the utilization of PGN as a nutrient source, involving exo-lytic N-acetylmuramidases with different modes of action, appears to be a general feature of bacteria, particularly among the phylum Bacteroidetes.

scholarly journals Peptidoglycan Salvage Enables the Periodontal Pathogen Tannerella forsythia to Survive within the Oral Microbial Community

2021 ◽  
pp. 1-12
Author(s):  
Isabel Hottmann ◽  
Marina Borisova ◽  
Christina Schäffer ◽  
Christoph Mayer
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Tooth Loss ◽  
De Novo ◽  
Periodontal Pathogen ◽  
Tannerella Forsythia ◽  
Gram Negative ◽  
Salvage Pathways ◽  
Axenic Growth ◽  
Nutrition Source

<i>Tannerella forsythia</i> is an anaerobic, fusiform Gram-negative oral pathogen strongly associated with periodontitis, a multibacterial inflammatory disease that leads to the destruction of the teeth-supporting tissue, ultimately causing tooth loss. To survive in the oral habitat, <i>T. forsythia</i> depends on cohabiting bacteria for the provision of nutrients. For axenic growth under laboratory conditions, it specifically relies on the external supply of <i>N</i>-acetylmuramic acid (MurNAc), which is an essential constituent of the peptidoglycan (PGN) of bacterial cell walls. <i>T. forsythia</i> comprises a typical Gram-negative PGN; however, as evidenced by genome sequence analysis, the organism lacks common enzymes required for the <i>de novo</i> synthesis of precursors of PGN, which rationalizes its MurNAc auxotrophy. Only recently insights were obtained into how <i>T. forsythia</i> gains access to MurNAc in its oral habitat, enabling synthesis of the own PGN cell wall. This report summarizes <i>T. forsythia</i>’s strategies to survive in the oral habitat by means of PGN salvage pathways, including recovery of exogenous MurNAc and PGN-derived fragments but also polymeric PGN, which are all derived from cohabiting bacteria either via cell wall turnover or decay of cells. Salvage of polymeric PGN presumably requires the removal of peptides from PGN by an unknown amidase, concomitantly with the translocation of the polymer across the outer membrane. Two recently identified exo-lytic <i>N</i>-acetylmuramidases (Tf_NamZ1 and Tf_NamZ2) specifically cleave the peptide-free, exogenous (nutrition source) PGN in the periplasm and release the MurNAc and disaccharide substrates for the transporters Tf_MurT and Tf_AmpG, respectively, whereas the peptide-containing, endogenous (the self-cell wall) PGN stays unattached. This review also outlines how <i>T. forsythia</i> synthesises the PGN precursors UDP-MurNAc and UDP-<i>N</i>-acetylglucosamine (UDP-GlcNAc), involving homologs of the <i>Pseudomonas</i> sp. recycling enzymes AmgK/MurU and a monofunctional uridylyl transferase (named Tf_GlmU*), respectively.

scholarly journals Characterization of a Natural, Stable, Reversible and Colourful Anthocyanidin Network from Sphagnum Moss Based Mainly on the Yellow Trans-Chalcone and Red Flavylium Cation Forms

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 709
Author(s):  
Helge Berland ◽  
Øyvind M. Andersen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Cell Wall ◽  
Peat Moss ◽  
Sphagnum Moss ◽  
Naturally Occurring ◽  
Two Component ◽  
Colour System ◽  
The Common ◽  
Cis And Trans

Anthocyanins with various functions in nature are one of the most important sources of colours in plants. They are based on anthocyanidins or 3-deoxyanthocyanidins having in common a C15-skeleton and are unique in terms of how each anthocyanidin is involved in a network of equilibria between different forms exhibiting their own properties including colour. Sphagnorubin C (1) isolated from the cell wall of peat moss (Sphagnum sp.) was in fairly acidic and neutral dimethyl sulfoxide characterized by nuclear magnetic resonance (NMR) and ultraviolet–visible (UV–vis) absorption techniques. At equilibrium, the network of 1 behaved as a two–component colour system involving the reddish flavylium cationic and the yellow trans–chalcone forms. The additional D- and E-rings connected to the common C15-skeleton extend the π-conjugation within the molecule and provide both bathochromic shifts in the absorption spectra of the various forms as well as a low isomerization barrier between the cis- and trans-chalcone forms. The hemiketal and cis-chalcone forms were thus not observed experimentally by NMR due to their short lives. The stable, reversible network of 1 with good colour contrast between its two components has previously not been reported for other natural anthocyanins and might thus have potential in future photochromic systems. This is the first full structural characterization of any naturally occurring anthocyanin chalcone form.

BIOTIN (BIOS IIB, VITAMIN H)--AN ESSENTIAL GROWTH FACTOR FOR CERTAIN STAPHYLOCOCCI

Science ◽  
1940 ◽  
Vol 91 (2372) ◽  
pp. 576-577 ◽  
Author(s):  
J. R. PORTER ◽  
M. J. PELCZAR
Keyword(s):  
Growth Factor ◽  
Essential Growth ◽  
Essential Growth Factor

scholarly journals Nonulosonic acids contribute to the pathogenicity of the oral bacterium Tannerella forsythia

2019 ◽  
Vol 9 (2) ◽  
pp. 20180064 ◽  
Author(s):  
Susanne Bloch ◽  
Markus B. Tomek ◽  
Valentin Friedrich ◽  
Paul Messner ◽  
Christina Schäffer
Keyword(s):  
Cell Surface ◽  
Current Knowledge ◽  
Cell Envelope ◽  
Treatment Strategies ◽  
Periodontal Pathogen ◽  
Tannerella Forsythia ◽  
Oral Bacterium ◽  
Complex Protein ◽  
Unique Cell ◽  
Systemic Health

Periodontitis is a polymicrobial, biofilm-caused, inflammatory disease affecting the tooth-supporting tissues. It is not only the leading cause of tooth loss worldwide, but can also impact systemic health. The development of effective treatment strategies is hampered by the complicated disease pathogenesis which is best described by a polymicrobial synergy and dysbiosis model. This model classifies the Gram-negative anaerobe Tannerella forsythia as a periodontal pathogen, making it a prime candidate for interference with the disease. Tannerella forsythia employs a protein O -glycosylation system that enables high-density display of nonulosonic acids via the bacterium's two-dimensional crystalline cell surface layer. Nonulosonic acids are sialic acid-like sugars which are well known for their pivotal biological roles. This review summarizes the current knowledge of T. forsythia' s unique cell envelope with a focus on composition, biosynthesis and functional implications of the cell surface O -glycan. We have obtained evidence that glycobiology affects the bacterium's immunogenicity and capability to establish itself in the polymicrobial oral biofilm. Analysis of the genomes of different T. forsythia isolates revealed that complex protein O -glycosylation involving nonulosonic acids is a hallmark of pathogenic T. forsythia strains and, thus, constitutes a valuable target for the design of novel anti-infective strategies to combat periodontitis.

scholarly journals Dysbiosis in the oral microbiomes of anti-CCP positive individuals at risk of developing rheumatoid arthritis

2020 ◽  
pp. annrheumdis-2020-216972
Author(s):  
Zijian Cheng ◽  
Thuy Do ◽  
Kulveer Mankia ◽  
Josephine Meade ◽  
Laura Hunt ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
At Risk ◽  
Risk Group ◽  
Orthologous Gene ◽  
Oral Microbiome ◽  
Periodontal Pathogen ◽  
P Value ◽  
Illumina Hiseq ◽  
Early Ra ◽  
Taxonomic Profile

ObjectivesAn increased prevalence of periodontitis and perturbation of the oral microbiome has been identified in patients with rheumatoid arthritis (RA). The periodontal pathogen Porphyromonas gingivalis may cause local citrullination of proteins, potentially triggering anti-citrullinated protein antibody production. However, it is not known if oral dysbiosis precedes the onset of clinical arthritis. This study comprehensively characterised the oral microbiome in anti-cyclic citrullinated peptide (anti-CCP) positive at-risk individuals without clinical synovitis (CCP+at risk).MethodsSubgingival plaque was collected from periodontally healthy and diseased sites in 48 CCP+at risk, 26 early RA and 32 asymptomatic healthy control (HC) individuals. DNA libraries were sequenced on the Illumina HiSeq 3000 platform. Taxonomic profile and functional capability of the subgingival microbiome were compared between groups.ResultsAt periodontally healthy sites, CCP+at risk individuals had significantly lower microbial richness compared with HC and early RA groups (p=0.004 and 0.021). Microbial community alterations were found at phylum, genus and species levels. A large proportion of the community differed significantly in membership (523 species; 35.6%) and structure (575 species; 39.1%) comparing CCP+at risk and HC groups. Certain core species, including P. gingivalis, had higher relative abundance in the CCP+at risk group. Seventeen clusters of orthologous gene functional units were significantly over-represented in the CCP+at risk group compared with HC (adjusted p value <0.05).ConclusionAnti-CCP positive at-risk individuals have dysbiotic subgingival microbiomes and increased abundance of P. gingivalis compared with controls. This supports the hypothesis that the oral microbiome and specifically P. gingivalis are important in RA initiation.

scholarly journals Analysis of oral microbiome from fossil human remains revealed the significant differences in virulence factors of modern and ancient Tannerella forsythia

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Anna Philips ◽  
Ireneusz Stolarek ◽  
Luiza Handschuh ◽  
Katarzyna Nowis ◽  
Anna Juras ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Human Remains ◽  
Oral Microbiome ◽  
Tannerella Forsythia

scholarly journals Inducible Expression of Human β-Defensin 2 byFusobacterium nucleatum in Oral Epithelial Cells: Multiple Signaling Pathways and Role of Commensal Bacteria in Innate Immunity and the Epithelial Barrier

2000 ◽  
Vol 68 (5) ◽  
pp. 2907-2915 ◽  
Author(s):  
Suttichai Krisanaprakornkit ◽  
Janet R. Kimball ◽  
Aaron Weinberg ◽  
Richard P. Darveau ◽  
Brian W. Bainbridge ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Cell Wall ◽  
Epithelial Cells ◽  
Signaling Pathways ◽  
Inducible Expression ◽  
Periodontal Pathogen ◽  
Gingival Tissue ◽  
Necrosis Factor Alpha ◽  
Tnf Α

ABSTRACT Human gingival epithelial cells (HGE) express two antimicrobial peptides of the β-defensin family, human β-defensin 1 (hBD-1) and hBD-2, as well as cytokines and chemokines that contribute to innate immunity. In the present study, the expression and transcriptional regulation of hBD-2 was examined. HBD-2 mRNA was induced by cell wall extract of Fusobacterium nucleatum, an oral commensal microorganism, but not by that of Porphyromonas gingivalis, a periodontal pathogen. HBD-2 mRNA was also induced by the proinflammatory cytokine tumor necrosis factor alpha (TNF-α) and phorbol myristate acetate (PMA), an epithelial cell activator. HBD-2 mRNA was also expressed in 14 of 15 noninflamed gingival tissue samples. HBD-2 peptide was detected by immunofluorescence in HGE stimulated with F. nucleatum cell wall, consistent with induction of the mRNA by this stimulant. Kinetic analysis indicates involvement of multiple distinct signaling pathways in the regulation of hBD-2 mRNA; TNF-α and F. nucleatum cell wall induced hBD-2 mRNA rapidly (2 to 4 h), while PMA stimulation was slower (∼10 h). In contrast, each stimulant induced interleukin 8 (IL-8) within 1 h. The role of TNF-α as an intermediary in F. nucleatum signaling was ruled out by addition of anti-TNF-α that did not inhibit hBD-2 induction. However, inhibitor studies show that F. nucleatum stimulation of hBD-2 mRNA requires both new gene transcription and new protein synthesis. Bacterial lipopolysaccharides isolated from Escherichia coli andF. nucleatum were poor stimulants of hBD-2, although they up-regulated IL-8 mRNA. Collectively, our findings show inducible expression of hBD-2 mRNA via multiple pathways in HGE in a pattern that is distinct from that of IL-8 expression. We suggest that different aspects of innate immune responses are differentially regulated and that commensal organisms have a role in stimulating mucosal epithelial cells in maintaining the barrier that contributes to homeostasis and host defense.

scholarly journals Novel class of glutathione transferases from cyanobacteria exhibit high catalytic activities towards naturally occurring isothiocyanates

2007 ◽  
Vol 406 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Eric Wiktelius ◽  
Gun Stenberg
Keyword(s):  
Catalytic Properties ◽  
Structural Features ◽  
Glutathione Transferases ◽  
Substrate Specificities ◽  
Catalytic Activities ◽  
Genome Databases ◽  
Naturally Occurring ◽  
Physiological Relevance ◽  
Associated Proteins

In the present paper, we report a novel class of GSTs (glutathione transferases), called the Chi class, originating from cyanobacteria and with properties not observed previously in prokaryotic enzymes. GSTs constitute a widespread multifunctional group of proteins, of which mammalian enzymes are the best characterized. Although GSTs have their origin in prokaryotes, few bacterial representatives have been characterized in detail, and the catalytic activities and substrate specificities observed have generally been very modest. The few well-studied bacterial GSTs have largely unknown physiological functions. Genome databases reveal that cyanobacteria have an extensive arsenal of glutathione-associated proteins. We have studied two cyanobacterial GSTs which are the first examples of bacterial enzymes that are as catalytically efficient as the best mammalian enzymes. GSTs from the thermophile Thermosynechococcus elongatus BP-1 and from Synechococcus elongatus PCC 6301 were found to catalyse the conjugation of naturally occurring plant-derived isothiocyanates to glutathione at high rates. The cyanobacterial GSTs studied are smaller than previously described members of this enzyme family, but display many of the typical structural features that are characteristics of GSTs. They are also active towards several classical substrates, but at the same moderate rates that have been observed for other GSTs derived from prokaryotes. The cloning, expression and characterization of two cyanobacterial GSTs are described. The possible significance of the observed catalytic properties is discussed in the context of physiological relevance and GST evolution.

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