scholarly journals Slipped strand mispairing in the gene encoding sialidase NanH3 in Gardnerella spp

2020 ◽  
Author(s):  
Shakya P. Kurukulasuriya ◽  
Mo H. Patterson ◽  
Janet E. Hill
Keyword(s):  
Cell Wall ◽  
Biofilm Formation ◽  
Gene Sequence ◽  
Phase Variation ◽  
Cell Wall Proteins ◽  
Vaginal Microbiome ◽  
Gene Encoding ◽  
Reading Frame ◽  
Sialidase Activity ◽  
Mucosal Surfaces

AbstractCell wall proteins with sialidase activity are involved in carbohydrate assimilation, adhesion to mucosal surfaces, and biofilm formation. Gardnerella spp. inhabit the human vaginal microbiome and encode up to three sialidase enzymes, two of which are suspected to be cell wall associated. Here we demonstrate that the gene encoding extracellular sialidase NanH3 is found almost exclusively in G. piotii and closely related Gardnerella genome sp. 3, and its presence correlates with sialidase positive phenotype in a collection of 112 Gardnerella isolates. The nanH3 gene sequence includes a homopolymeric repeat of cytosines that varies in length within cell populations, indicating that this gene is subject to slipped-strand mispairing, a mechanisms of phase variation in bacteria. Variation in the length of the homopolymer sequence results in encoding of either the full length sialidase protein or truncated peptides lacking the sialidase domain due to introduction of reading-frame shifts and premature stop codons. Phase variation in NanH3 may be involved in immune evasion or modulation of adhesion to host epithelial cells, and formation of biofilms characteristic of the vaginal dysbiosis known as bacterial vaginosis.

scholarly journals Slipped strand mispairing in the gene encoding sialidase NanH3 in Gardnerella spp.

2020 ◽  
Author(s):  
Shakya P. Kurukulasuriya ◽  
Mo H. Patterson ◽  
Janet E. Hill
Keyword(s):  
Cell Wall ◽  
Biofilm Formation ◽  
Gene Sequence ◽  
Phase Variation ◽  
Cell Wall Proteins ◽  
Vaginal Microbiome ◽  
Gene Encoding ◽  
Reading Frame ◽  
Sialidase Activity ◽  
Mucosal Surfaces

Cell wall proteins with sialidase activity are involved in carbohydrate assimilation, adhesion to mucosal surfaces, and biofilm formation. Gardnerella spp. inhabit the human vaginal microbiome and encode up to three sialidase enzymes, two of which are suspected to be cell wall associated. Here we demonstrate that the gene encoding extracellular sialidase NanH3 is found almost exclusively in G. piotii and closely related Gardnerella genome sp. 3, and its presence correlates with sialidase positive phenotype in a collection of 112 Gardnerella isolates. The nanH3 gene sequence includes a homopolymeric repeat of cytosines that varies in length within cell populations, indicating that this gene is subject to slipped-strand mispairing, a mechanisms of phase variation in bacteria. Variation in the length of the homopolymer sequence results in encoding of either the full length sialidase protein or truncated peptides lacking the sialidase domain due to introduction of reading-frame shifts and premature stop codons. Phase variation in NanH3 may be involved in immune evasion or modulation of adhesion to host epithelial cells, and formation of biofilms characteristic of the vaginal dysbiosis known as bacterial vaginosis.

scholarly journals Phase Variation of Campylobacter jejuni 81-176 Lipooligosaccharide Affects Ganglioside Mimicry and Invasiveness In Vitro

2002 ◽  
Vol 70 (2) ◽  
pp. 787-793 ◽  
Author(s):  
Patricia Guerry ◽  
Christine M. Szymanski ◽  
Martina M. Prendergast ◽  
Thomas E. Hickey ◽  
Cheryl P. Ewing ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Phase Variation ◽  
Outer Core ◽  
Gene Encoding ◽  
Site Specific ◽  
Reading Frame ◽  
Specific Mutation ◽  
Normal Human ◽  
A Site

ABSTRACT The outer cores of the lipooligosaccharides (LOS) of many strains of Campylobacter jejuni mimic human gangliosides in structure. A population of cells of C. jejuni strain 81-176 produced a mixture of LOS cores which consisted primarily of structures mimicking GM2 and GM3 gangliosides, with minor amounts of structures mimicking GD1b and GD2. Genetic analyses of genes involved in the biosynthesis of the outer core of C. jejuni 81-176 revealed the presence of a homopolymeric tract of G residues within a gene encoding CgtA, an N-acetylgalactosaminyltransferase. Variation in the number of G residues within cgtA affected the length of the open reading frame, and these changes in cgtA corresponded to a change in LOS structure from GM2 to GM3 ganglioside mimicry. Site-specific mutation of cgtA in 81-176 resulted in a major LOS core structure that lacked GalNAc and resembled GM3 ganglioside. Compared to wild-type 81-176, the cgtA mutant showed a significant increase in invasion of INT407 cells. In comparison, a site-specific mutation of the neuC1 gene resulted in the loss of sialic acid in the LOS core and reduced resistance to normal human serum but had no affect on invasion of INT407 cells.

scholarly journals Chitin Utilization by the Insect-Transmitted Bacterium Xylella fastidiosa

2010 ◽  
Vol 76 (18) ◽  
pp. 6134-6140 ◽  
Author(s):  
Nabil Killiny ◽  
Simone S. Prado ◽  
Rodrigo P. P. Almeida
Keyword(s):  
Carbon Source ◽  
Biofilm Formation ◽  
Xylella Fastidiosa ◽  
Chitinolytic Activity ◽  
Gene Encoding ◽  
Reading Frame ◽  
Biological Assays ◽  
Chitinase A ◽  
Transcriptional Changes

ABSTRACT Xylella fastidiosa is an insect-borne bacterium that colonizes xylem vessels of a large number of host plants, including several crops of economic importance. Chitin is a polysaccharide present in the cuticle of leafhopper vectors of X. fastidiosa and may serve as a carbon source for this bacterium. Biological assays showed that X. fastidiosa reached larger populations in the presence of chitin. Additionally, chitin induced phenotypic changes in this bacterium, notably increasing adhesiveness. Quantitative PCR assays indicated transcriptional changes in the presence of chitin, and an enzymatic assay demonstrated chitinolytic activity by X. fastidiosa. An ortholog of the chitinase A gene (chiA) was identified in the X. fastidiosa genome. The in silico analysis revealed that the open reading frame of chiA encodes a protein of 351 amino acids with an estimated molecular mass of 40 kDa. chiA is in a locus that consists of genes implicated in polysaccharide degradation. Moreover, this locus was also found in the genomes of closely related bacteria in the genus Xanthomonas, which are plant but not insect associated. X. fastidiosa degraded chitin when grown on a solid chitin-yeast extract-agar medium and grew in liquid medium with chitin as the sole carbon source; ChiA was also determined to be secreted. The gene encoding ChiA was cloned into Escherichia coli, and endochitinase activity was detected in the transformant, showing that the gene is functional and involved in chitin degradation. The results suggest that X. fastidiosa may use its vectors' foregut surface as a carbon source. In addition, chitin may trigger X. fastidiosa's gene regulation and biofilm formation within vectors. Further work is necessary to characterize the role of chitin and its utilization in X. fastidiosa.

scholarly journals Hwp1 and Related Adhesins Contribute to both Mating and Biofilm Formation in Candida albicans

2009 ◽  
Vol 8 (12) ◽  
pp. 1909-1913 ◽  
Author(s):  
Iuliana V. Ene ◽  
Richard J. Bennett
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Sexual Differentiation ◽  
Biofilm Formation ◽  
Filamentous Growth ◽  
Cell Wall Proteins ◽  
Related Cell

ABSTRACT Candida albicans Hwp1, Hwp2, and Rbt1 are related cell wall proteins expressed during the programs of sexual differentiation and filamentous growth. In this study, we compare strains lacking either single factors or a combination of these genes, and we demonstrate distinct but overlapping roles in mating and biofilm formation.

scholarly journals Cloning and Expression of the algL Gene, Encoding the Azotobacter chroococcum Alginate Lyase: Purification and Characterization of the Enzyme

1999 ◽  
Vol 181 (5) ◽  
pp. 1409-1414 ◽  
Author(s):  
Ana Peciña ◽  
Alberto Pascual ◽  
Antonio Paneque
Keyword(s):  
Gene Sequence ◽  
Azotobacter Vinelandii ◽  
Alginate Lyase ◽  
Azotobacter Chroococcum ◽  
Open Reading Frame ◽  
Cloning And Expression ◽  
Gene Encoding ◽  
Reading Frame ◽  
Encoding Gene

ABSTRACT The alginate lyase-encoding gene (algL) ofAzotobacter chroococcum was localized to a 3.1-kbEcoRI DNA fragment that revealed an open reading frame of 1,116 bp. This open reading frame encodes a protein of 42.98 kDa, in agreement with the value previously reported by us for this protein. The deduced protein has a potential N-terminal signal peptide that is consistent with its proposed periplasmic location. The analysis of the deduced amino acid sequence indicated that the gene sequence has a high homology (90% identity) to the Azotobacter vinelandii gene sequence, which has very recently been deposited in the GenBank database, and that it has 64% identity to the Pseudomonas aeruginosa gene sequence but that it has rather low homology (15 to 22% identity) to the gene sequences encoding alginate lyase in other bacteria. The A. chroococcum AlgL protein was overproduced in Escherichia coli and purified to electrophoretic homogeneity in a two-step chromatography procedure on hydroxyapatite and phenyl-Sepharose. The kinetic and molecular parameters of the recombinant alginate lyase are similar to those found for the native enzyme.

scholarly journals Involvement of Sortase Anchoring of Cell Wall Proteins in Biofilm Formation by Streptococcusmutans

2005 ◽  
Vol 73 (6) ◽  
pp. 3773-3777 ◽  
Author(s):  
Céline M. Lévesque ◽  
Elena Voronejskaia ◽  
Yi-Chen Cathy Huang ◽  
Richard W. Mair ◽  
Richard P. Ellen ◽  
...  
Keyword(s):  
Cell Wall ◽  
Biofilm Formation ◽  
Cell Wall Proteins ◽  
Planktonic Cells ◽  
Genes Encoding

ABSTRACT Streptococcus mutans is one of the best-known biofilm-forming organisms associated with humans. We investigated the role of the sortase gene (srtA) in monospecies biofilm formation and observed that inactivation of srtA caused a decrease in biofilm formation. Genes encoding three putative sortase-dependent proteins were also found to be up-regulated in biofilms versus planktonic cells and mutations in these genes resulted in reduced biofilm biomass.

scholarly journals Cloning, Identification, and Characterization of therpoS-Like Sigma FactorrpoXfromVibrio alginolyticus

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Jing-jing Zhao ◽  
Chang Chen ◽  
Lv-ping Zhang ◽  
Chao-qun Hu
Keyword(s):  
Hydrogen Peroxide ◽  
Survival Rate ◽  
Sigma Factor ◽  
Biofilm Formation ◽  
Phase Variation ◽  
Wild Type ◽  
Switching Rate ◽  
Gene Encoding ◽  
Identification And Characterization

Vibrio alginolyticusZJ-51 displays phase variation between opaque/rugose colonies (Op) and translucent/smooth colonies (Tr). These colony variants show great differences in biofilm formation and motility. In this study, a gene encoding for anrpoS-like sigma factor,rpoX, has been cloned and characterized. The absence ofrpoXdid not affect colony switching rate but did decrease biofilm formation in both the Op and the Tr variants. When challenged with hydrogen peroxide, theΔrpoXin the Op background showed a slightly higher survival rate compared with the wild type, whereas survival was decreased in the Tr background. Deletion ofrpoXin the Tr background resulted in a higher ability to resist ethanol challenges and to survive hyperosmolarity challenges, and in the Op background the opposite phenotype was observed. This indicates that therpoXgene is involved in biofilm formation and stress response but the effects are controlled by colony phase variation inV. alginolyticus.

scholarly journals Uncovering Roles of Streptococcus gordonii SrtA-Processed Proteins in the Biofilm Lifestyle

2020 ◽  
Vol 203 (2) ◽  
pp. e00544-20
Author(s):  
Brittany L. Nairn ◽  
Grace T. Lee ◽  
Ashwani K. Chumber ◽  
Patrick R. Steck ◽  
Mahmoud O. Mire ◽  
...  
Keyword(s):  
Cell Wall ◽  
Biofilm Formation ◽  
Deletion Mutant ◽  
Ex Vivo ◽  
Sortase A ◽  
Cell Wall Proteins ◽  
Mutant Library ◽  
Rich Medium ◽  
Content Type ◽  
Markerless Deletion

ABSTRACTStreptococcus gordonii is a commensal oral organism. Harmless in the oral cavity, S. gordonii is an opportunistic pathogen. S. gordonii adheres to body surfaces using surface adhesive proteins (adhesins), which are critical to subsequent formation of biofilm communities. As in most Gram-positive bacteria, S. gordonii surface proteins containing the C-terminal LPXTG motif cleavage sequence are processed by sortase A (SrtA) to become covalently attached to the cell wall. To characterize the functional diversity and redundancy in the family of SrtA-processed proteins, an S. gordonii DL1 markerless deletion mutant library was constructed of each of the 26 putative SrtA-processed proteins. Each library member was evaluated for growth in rich medium, biofilm formation on plastic, saliva and salivary fractions, cell surface hydrophobicity (CSH), hemagglutination, and integration into an ex vivo plaque biofilm community. Library members were compared to the non-SrtA-processed adhesins AbpA and AbpB. While no major growth differences in rich medium were observed, many S. gordonii LPXTG/A proteins impacted biofilm formation on one or more of the substrates. Several mutants showed significant differences in hemagglutination, hydrophobicity, or fitness in the ex vivo plaque model. From the identification of redundant and unique functions in these in vitro and ex vivo systems, functional stratification among the LPXTG/A proteins is apparent.IMPORTANCES. gordonii interactions with its environment depend on the complement of cell wall proteins. A subset of these cell wall proteins requires processing by the enzyme sortase A (SrtA). The identification of SrtA-processed proteins and their functional characterization will help the community to better understand how S. gordonii engages with its surroundings, including other microbes, integrates into the plaque community, adheres to the tooth surface, and hematogenously disseminates to cause blood-borne infections. This study identified 26 putative SrtA-processed proteins through creation of a markerless deletion mutant library. The library was subject to functional screens that were chosen to better understand key aspects of S. gordonii physiology and pathogenesis.

scholarly journals Promotion of Efficient Saccharification of Crystalline Cellulose by Aspergillus fumigatus Swo1

2010 ◽  
Vol 76 (8) ◽  
pp. 2556-2561 ◽  
Author(s):  
Xin-ai Chen ◽  
Nobuhiro Ishida ◽  
Nemuri Todaka ◽  
Risa Nakamura ◽  
Jun-ichi Maruyama ◽  
...  
Keyword(s):  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Plant Cell Wall ◽  
Sequence Similarity ◽  
Crystalline Cellulose ◽  
Carbohydrate Binding ◽  
Cell Wall Proteins ◽  
Gene Encoding ◽  
Endoglucanase Activity ◽  
Novel Approach

ABSTRACT Swollenin is a protein from Trichoderma reesei that has a unique activity for disrupting cellulosic materials, and it has sequence similarity to expansins, plant cell wall proteins that have a loosening effect that leads to cell wall enlargement. In this study we cloned a gene encoding a swollenin-like protein, Swo1, from the filamentous fungus Aspergillus fumigatus, and designated the gene Afswo1. AfSwo1 has a bimodular structure composed of a carbohydrate-binding module family 1 (CBM1) domain and a plant expansin-like domain. AfSwo1 was produced using Aspergillus oryzae for heterologous expression and was easily isolated by cellulose-affinity chromatography. AfSwo1 exhibited weak endoglucanase activity toward carboxymethyl cellulose (CMC) and bound not only to crystalline cellulose Avicel but also to chitin, while showing no detectable affinity to xylan. Treatment by AfSwo1 caused disruption of Avicel into smaller particles without any detectable reducing sugar. Furthermore, simultaneous incubation of AfSwo1 with a cellulase mixture facilitated saccharification of Avicel. Our results provide a novel approach for efficient bioconversion of crystalline cellulose into glucose by use of the cellulose-disrupting protein AfSwo1.

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