1
|
Pascal SB, Lorenzo R, Farías MVN, Rossen JW, Lucchesi PMA, Krüger A. Characterization of the flanking region of the Shiga toxin operon in Stx2a bacteriophages reveals a diversity of the NanS-p sialate O-acetylesterase gene. AIMS Microbiol 2023; 9:570-590. [PMID: 37649799 PMCID: PMC10462455 DOI: 10.3934/microbiol.2023030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 09/01/2023] Open
Abstract
Shiga toxin-producing E. coli (STEC) are diarrheagenic strains that can cause bloody diarrhea and hemolytic-uremic syndrome. Their main virulence factor, the Shiga toxin (Stx), is encoded by phages integrated into the bacterial chromosome. Stx phages are widely diverse and carry many genes with limited or unknown function. As the toxin subtype Stx2a is associated with highly pathogenic strains, this study was mainly focused on the characterization of the stx flanking region of Stx2a phages. Of particular interest was a sialate O-acetylesterase (NanS-p), which has been described previously to be encoded downstream stx in some phage genomes and may confer a growth advantage for STEC. Complete DNA sequences of Stx2a phages and prophages were retrieved from the GenBank database, and the genomic regions from anti-terminator Q to holin S genes were bioinformatically analyzed. Predicted NanSp sequences from phages encoding other Stx subtypes were also studied. Additionally, expression of nanS-p was quantified by qPCR in strains selected from our laboratory collection. The analysis of Stx2a phage genomes showed that all carried the Q, stx2a, nanS-p and S genes, but with allele diversity and other sequence differences. In particular, sequence differences were detected in each of the three domains of NanS-p esterases encoded by Stx2a phages and other Stx phages; however, nanS-p was not identified in the Stx2e, Stx2f and Stx2g phages analyzed. The expression of nanS-p increased in most stx2a-positive strains under phage inducing conditions, as was previously shown for stx2a. As the present work showed diversity at the Q-S region among Stx phages, and particularly in the encoded NanS-p enzyme, future studies will be necessary to evaluate if NanS-p variants differ in their activity and to assess the impact of the absence of nanS-p in certain Stx phages.
Collapse
Affiliation(s)
- Stefanía B. Pascal
- Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Facultad de Ciencias Veterinarias, CISAPA, Tandil, Buenos Aires, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
| | - Ramiro Lorenzo
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
- Laboratory of Neurophysiology, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - María Victoria Nieto Farías
- Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Facultad de Ciencias Veterinarias, CISAPA, Tandil, Buenos Aires, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
| | - John W.A. Rossen
- Laboratory of Medical Microbiology and Infectious Diseases, Isala Hospital, Zwolle, The Netherlands
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Paula M. A. Lucchesi
- Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Facultad de Ciencias Veterinarias, CISAPA, Tandil, Buenos Aires, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
| | - Alejandra Krüger
- Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Facultad de Ciencias Veterinarias, CISAPA, Tandil, Buenos Aires, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
| |
Collapse
|
2
|
Albers M, Schröter L, Belousov S, Hartmann M, Grove M, Abeln M, Mühlenhoff M. The sialyl-O-acetylesterase NanS of Tannerella forsythia encompasses two catalytic modules with different regiospecificity for O7 and O9 of sialic acid. Glycobiology 2021; 31:1176-1191. [PMID: 33909048 DOI: 10.1093/glycob/cwab034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/14/2021] [Accepted: 04/15/2021] [Indexed: 12/12/2022] Open
Abstract
The periodontal pathogen Tannerella forsythia utilizes host sialic acids as a nutrient source. To also make O-acetylated sialyl residues susceptible to the action of its sialidase and sialic acid up-take system, Tannerella produces NanS, an O-acetylesterase with two putative catalytic domains. Here, we analyzed NanS by homology modeling, predicted a catalytic serine-histidine-aspartate triad for each catalytic domain and performed individual domain inactivation by single alanine exchanges of the triad nucleophiles S32 and S311. Subsequent functional analyses revealed that both domains possess sialyl-O-acetylesterase activity, but differ in their regioselectivity with respect to position O9 and O7 of sialic acid. The 7-O-acetylesterase activity inherent to the C-terminal domain of NanS is unique among sialyl-O-acetylesterases and fills the current gap in tools targeting 7-O-acetylation. Application of the O7-specific variant NanS-S32A allowed us to evidence the presence of cellular 7,9-di-O-acetylated sialoglycans by monitoring the gain in 9-O-acetylation upon selective removal of acetyl groups from O7. Moreover, we established de-7,9-O-acetylation by wild-type NanS as an easy and efficient method to validate the specific binding of three viral lectins commonly used for the recognition of (7),9-O-acetylated sialoglycans. Their binding critically depends on an acetyl group in O9, yet de-7,9-O-acetylation proved advantageous over de-9-O-acetylation as the additional removal of the 7-O-acetyl group eliminated ligand formation by 7,9-ester migration. Together, our data show that NanS gained dual functionality through recruitment of two esterase modules with complementary activities. This enables Tannerella to scavenge 7,9-di-O-acetylated sialyl residues and provides a novel, O7-specific tool for studying sialic acid O-acetylation.
Collapse
Affiliation(s)
- Malena Albers
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Larissa Schröter
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Sergej Belousov
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Maike Hartmann
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Melanie Grove
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Markus Abeln
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Martina Mühlenhoff
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| |
Collapse
|
3
|
Rodríguez-Rubio L, Haarmann N, Schwidder M, Muniesa M, Schmidt H. Bacteriophages of Shiga Toxin-Producing Escherichia coli and Their Contribution to Pathogenicity. Pathogens 2021; 10:404. [PMID: 33805526 PMCID: PMC8065619 DOI: 10.3390/pathogens10040404] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/18/2021] [Accepted: 03/24/2021] [Indexed: 12/25/2022] Open
Abstract
Shiga toxins (Stx) of Shiga toxin-producing Escherichia coli (STEC) are generally encoded in the genome of lambdoid bacteriophages, which spend the most time of their life cycle integrated as prophages in specific sites of the bacterial chromosome. Upon spontaneous induction or induction by chemical or physical stimuli, the stx genes are co-transcribed together with the late phase genes of the prophages. After being assembled in the cytoplasm, and after host cell lysis, mature bacteriophage particles are released into the environment, together with Stx. As members of the group of lambdoid phages, Stx phages share many genetic features with the archetypical temperate phage Lambda, but are heterogeneous in their DNA sequences due to frequent recombination events. In addition to Stx phages, the genome of pathogenic STEC bacteria may contain numerous prophages, which are either cryptic or functional. These prophages may carry foreign genes, some of them related to virulence, besides those necessary for the phage life cycle. Since the production of one or more Stx is considered the major pathogenicity factor of STEC, we aim to highlight the new insights on the contribution of Stx phages and other STEC phages to pathogenicity.
Collapse
Affiliation(s)
- Lorena Rodríguez-Rubio
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Diagonal 643, 08028 Barcelona, Spain; (L.R.-R.); (M.M.)
| | - Nadja Haarmann
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, 70599 Stuttgart, Germany; (N.H.); (M.S.)
| | - Maike Schwidder
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, 70599 Stuttgart, Germany; (N.H.); (M.S.)
| | - Maite Muniesa
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Diagonal 643, 08028 Barcelona, Spain; (L.R.-R.); (M.M.)
| | - Herbert Schmidt
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, 70599 Stuttgart, Germany; (N.H.); (M.S.)
| |
Collapse
|