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Lingyan Li, Xuewei Pan, Xiaoli Cui, Qinghui Sun, Xiaojing Yang, Hongjiang Yang
Phage genomic information and the nature of host-phage interactions are important for phage applications. In this study, Pseudomonas aeruginosa phage K5 is characterized as a linear double-stranded genomic DNA molecule of 93,754 bp with identical 1182-bp direct terminal repeats. Comparative genomic analysis reveals that phage K5 is highly homologous to the "PaP1-like" phages. Thirteen mutants resistant to phage K5 are screened in a transposon mutant library. The disrupted genetic loci are identified as gene Y880_RS05480 encoding a putative O-antigen polymerase Wzy and gene wapH encoding a glycosyltransferase...
September 16, 2016: Journal of Basic Microbiology
Nathan A M Chrismas, Gary Barker, Alexandre M Anesio, Patricia Sánchez-Baracaldo
BACKGROUND: Cyanobacteria are major primary producers in extreme cold ecosystems. Many lineages of cyanobacteria thrive in these harsh environments, but it is not fully understood how they survive in these conditions and whether they have evolved specific mechanisms of cold adaptation. Phormidesmis priestleyi is a cyanobacterium found throughout the cold biosphere (Arctic, Antarctic and alpine habitats). Genome sequencing of P. priestleyi BC1401, an isolate from a cryoconite hole on the Greenland Ice Sheet, has allowed for the examination of genes involved in cold shock response and production of extracellular polymeric substances (EPS)...
2016: BMC Genomics
Susana Merino, Victor Gonzalez, Juan M Tomás
In the Wzx/Wzy-dependent assembled pathway, the assembled O-antigen repeat units are translocated from the cytosolic to the periplasmic face of the inner membrane by a Wzx translocase and then polymerized by the integral membrane protein Wzy to form a glycan chain. We demonstrate that the activity of the Escherichia coli O-antigen polymerase (Wzy) is dependent on the first sugar of the O-antigen repeat unit to produce the O-antigen polymerization and therefore, there is a need for a concerted action with the enzyme transferring the initial HexNAc to undecaprenyl phosphate (UDP-HexNAc: polyprenol-P HexNAc-1-P transferase)...
July 2016: Future Microbiology
Lei Li, Robert L Woodward, Weiqing Han, Jingyao Qu, Jing Song, Cheng Ma, Peng G Wang
Polysaccharides are essential and immunologically relevant components of bacterial cell walls. These biomolecules can be found covalently attached to lipids (e.g., O-polysaccharide (PS) contains undecaprenyl and lipopolysaccharide (LPS) contains lipid A) or noncovalently associated with cell wells (e.g., capsular PS (CPS)). Although extensive genetic studies have indicated that the Wzy-dependent biosynthetic pathway is primarily responsible for producing such polysaccharides, in vitro biochemical studies are needed to determine, for example, which gene product is responsible for catalyzing each step in the pathway, and to reveal molecular details about the Wzx translocase, Wzy polymerase and O-PS chain-length determinant...
July 2016: Nature Protocols
Keding Cheng, Huixia Chui, Larissa Domish, Angela Sloan, Drexler Hernandez, Stuart McCorrister, Alyssia Robinson, Matthew Walker, Lorea A M Peterson, Miles Majcher, Sam Ratnam, David J M Haldane, Sadjia Bekal, John Wylie, Linda Chui, Shaun Tyler, Bianli Xu, Aleisha Reimer, Celine Nadon, J David Knox, Gehua Wang
Mass spectrometry-based phenotypic H-antigen typing (MS-H) combined with whole-genome-sequencing-based genetic identification of H antigens, O antigens, and toxins (WGS-HOT) was used to type 60 clinical Escherichia coli isolates, 43 of which were previously identified as nonmotile, H type undetermined, or O rough by serotyping or having shown discordant MS-H and serotyping results. Whole-genome sequencing confirmed that MS-H was able to provide more accurate data regarding H antigen expression than serotyping...
August 2016: Journal of Clinical Microbiology
Yaoqin Hong, Peter R Reeves
The Wzx/Wzy O-antigen pathway involves synthesis of a repeat unit (O unit) consisting of 3 to 8 sugars on an inner-membrane-embedded lipid carrier. These O units are translocated across the membrane to its periplasmic face by Wzx, while retaining linkage to the carrier, and then polymerized by Wzy to O-antigen polymer, which WaaL ligase transfers to a lipopolysaccharide precursor to complete lipopolysaccharide synthesis, concomitantly releasing the lipid carrier. This lipid carrier is also used for peptidoglycan assembly, and sequestration is known to be toxic...
January 2016: MSphere
Xiaomei Zhao, Guiming Zhao, Ping Wang, Ying Chen, Yanchao Jiao, Adong Luo
OBJECTIVE: To establish a rapid assay to detect enterohemorrhagic Escherichia coli O157 (E. coli O157) and enterohemorrhagic Escherichia coli O104 (E. coli O104) in the legume plants and its products by using the duplex real-time PCR. METHODS: Based on part fragments of E. coli O157 specific gene rfbE and E. coli O104 specific gene wzy, primers and Taq-Man probes were designed. Results DNA (Q157): DNA (O104) = 1 : 3, DNA 2 μL, Master Mix 12.5 μL, primers (10 μmol/L) 1 μL,Taq-Man probes( 10 μmol/L) 0...
March 2016: Wei Sheng Yan Jiu, Journal of Hygiene Research
Atsushi Iguchi, Sunao Iyoda, Kazuko Seto, Hironobu Nishii, Makoto Ohnishi, Hirohisa Mekata, Yoshitoshi Ogura, Tetsuya Hayashi
Serotyping is one of the typing techniques used to classify strains within the same species. O-serogroup diversification shows a strong association with the genetic diversity of O-antigen biosynthesis genes. In a previous study, based on the O-antigen biosynthesis gene cluster (O-AGC) sequences of 184 known Escherichia coli O serogroups (from O1 to O187), we developed a comprehensive and practical molecular O serogrouping (O genotyping) platform using a polymerase chain reaction (PCR) method, named E. coli O-genotyping PCR...
2016: Frontiers in Microbiology
Johanna J Kenyon, Mikhail M Shneider, Sofya N Senchenkova, Alexander S Shashkov, Maria N Siniagina, Sergey Y Malanin, Anastasiya V Popova, Konstantin A Miroshnikov, Ruth M Hall, Yuriy A Knirel
Polymerization of the oligosaccharides (K units) of complex capsular polysaccharides (CPSs) requires a Wzy polymerase, which is usually encoded in the gene cluster that directs K unit synthesis. Here, a gene cluster at the Acinetobacter K locus (KL) that lacks a wzy gene, KL19, was found in Acinetobacter baumannii ST111 isolates 28 and RBH2 recovered from hospitals in the Russian Federation and Australia, respectively. However, these isolates produced long-chain capsule, and a wzy gene was found in a 6.1 kb genomic island (GI) located adjacent to the cpn60 gene...
August 2016: Microbiology
Jumpei Uchiyama, Masato Suzuki, Koji Nishifuji, Shin-Ichiro Kato, Reina Miyata, Tadahiro Nasukawa, Kotoe Yamaguchi, Iyo Takemura-Uchiyama, Takako Ujihara, Hidekatsu Shimakura, Hironobu Murakami, Noriaki Okamoto, Yoshihiko Sakaguchi, Keigo Shibayama, Masahiro Sakaguchi, Shigenobu Matsuzaki
UNLABELLED: Pseudomonas aeruginosa causes serious intractable infections in humans and animals. Bacteriophage (phage) therapy has been applied to treat P. aeruginosa infections, and phages belonging to the PB1-like virus genus in the Myoviridae family have been used as therapeutic phages. To achieve safer and more effective phage therapy, the use of preadapted phages is proposed. To understand in detail such phage preadaptation, the short-term antagonistic evolution of bacteria and phages should be studied...
August 1, 2016: Applied and Environmental Microbiology
Zhifeng Duan, Tomasz Niedziela, Czeslaw Lugowski, Boyang Cao, Tianwei Wang, Lingling Xu, Baopeng Yang, Bin Liu, Lei Wang
Hafnia alvei is a facultative and rod-shaped gram-negative bacterium that belongs to the Enterobacteriaceae family. Although it has been more than 50 years since the genus was identified, very little is known about variations among Hafnia species. Diversity in O-antigens (O-polysaccharide, OPS) is thought to be a major factor in bacterial adaptation to different hosts and situations and variability in the environment. Antigenic variation is also an important factor in pathogenicity that has been used to define clones within a number of species...
2016: PloS One
Véronique L Taylor, Jesse F J Hoage, Sandra Wingaard Thrane, Steven M Huszczynski, Lars Jelsbak, Joseph S Lam
Pseudomonas aeruginosa is a Gram-negative bacterium that produces highly varied lipopolysaccharide (LPS) structures. The O antigen (O-Ag) in the LPS is synthesized through the Wzx/Wzy-dependent pathway where lipid-linked O-Ag repeats are polymerized by Wzy. Horizontal-gene transfer has been associated with O-Ag diversity. The O-Ag present on the surface of serotypes O5 and O16, differ in the intra-molecular bonds, α and β, respectively; the latter arose from the action of three genes in a serotype converting unit acquired from bacteriophage D3, including a β-polymerase (Wzyβ)...
2016: Frontiers in Microbiology
Qiong Liu, Qing Liu, Xinxin Zhao, Tian Liu, Jie Yi, Kang Liang, Qingke Kong
Lipopolysaccharide (LPS) is a major virulence factor present in the outer membrane of Salmonella enterica serovar Typhimurium (S. Typhimurium). Outer membrane proteins (OMPs) from Salmonella show high immunogenicity and provide protection against Salmonella infection, and truncated LPS alters the outer membrane composition of the cell wall. In our previous study, we demonstrated that Salmonella mutants carrying truncated LPS failed to induce strong immune responses and cross-reaction to other enteric bacteria, due to their high attenuation and low colonization in the host...
2016: International Journal of Molecular Sciences
Xuewei Pan, Xiaoli Cui, Fenjiao Zhang, Yang He, Lingyan Li, Hongjiang Yang
Phage therapy requires the comprehensive understanding of the mechanisms underlying the host-phage interactions. In this work, to identify the genes related to Pseudomonas aeruginosa phage K8 receptor synthesis, 16 phage-resistant mutants were selected from a Tn5G transposon mutant library of strain PAK. The disrupted genetic loci were identified and they were related to O-specific antigen (OSA) synthesis, including gene wbpR, ssg, wbpV, wbpO, and Y880_RS05480, which encoded a putative O-antigen polymerase Wzy...
2016: Frontiers in Microbiology
Véronique L Taylor, Steven M Huszczynski, Joseph S Lam
Bacterial polysaccharides play an essential role in cell viability, virulence, and evasion of host defenses. Although the polysaccharides themselves are highly diverse, the pathways by which bacteria synthesize these essential polymers are conserved in both Gram-negative and Gram-positive organisms. By utilizing a lipid linker, a series of glycosyltransferases and integral membrane proteins act in concert to synthesize capsular polysaccharide, teichoic acid, and teichuronic acid. The pathways used to produce these molecules are the Wzx/Wzy-dependent, the ABC-transporter-dependent, and the synthase-dependent pathways...
February 9, 2016: Current Topics in Microbiology and Immunology
Sabine Delannoy, Byron D Chaves, Sarah A Ison, Hattie E Webb, Lothar Beutin, José Delaval, Isabelle Billet, Patrick Fach
Current methods for screening Enterohemorrhagic Escherichia coli (EHEC) O157 and non-O157 in beef enrichments typically rely on the molecular detection of stx, eae, and serogroup-specific wzx or wzy gene fragments. As these genetic markers can also be found in some non-EHEC strains, a number of "false positive" results are obtained. Here, we explore the suitability of five novel molecular markers, espK, espV, ureD, Z2098, and CRISPRO26:H11 as candidates for a more accurate screening of EHEC strains of greater clinical significance in industrialized countries...
2016: Frontiers in Microbiology
Alexander S Shashkov, Johanna J Kenyon, Sof'ya N Senchenkova, Mikhail M Shneider, Anastasiya V Popova, Nikolay P Arbatsky, Konstantin A Miroshnikov, Nikolay V Volozhantsev, Ruth M Hall, Yuriy A Knirel
Capsular polysaccharides (CPSs), from Acinetobacter baumannii isolates 1432, 4190 and NIPH 70, which have related gene content at the K locus, were examined, and the chemical structures established using 2D(1)H and(13)C NMR spectroscopy. The three isolates produce the same pentasaccharide repeat unit, which consists of 5-N-acetyl-7-N-[(S)-3-hydroxybutanoyl] (major) or 5,7-di-N-acetyl (minor) derivatives of 5,7-diamino-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulosonic (legionaminic) acid (Leg5Ac7R), D-galactose, N-acetyl-D-galactosamine and N-acetyl-D-glucosamine...
May 2016: Glycobiology
Eun Hwa Choi, Fan Zhang, Ying-Jie Lu, Richard Malley
The efficacy of the serotype 3 (ST3) pneumococcal conjugate vaccine (PCV) remains unclear. While the synthesis of capsular polysaccharide (CPS) of most serotypes is wzy dependent, the strains of two serotypes, 3 and 37, synthesize CPS by the synthase-dependent pathway, resulting in a polysaccharide that is not covalently linked to peptidoglycan and can be released during growth. We hypothesized that the release of CPS during growth reduces anti-type 3 CPS antibody-mediated protection and may explain the lower efficacy of the type 3 component of PCV than that of other PCVs...
February 2016: Clinical and Vaccine Immunology: CVI
Yi-Jiun Pan, Tzu-Lung Lin, Chun-Tang Chen, Yi-Yin Chen, Pei-Fang Hsieh, Chun-Ru Hsu, Meng-Chuan Wu, Jin-Town Wang
A total of 79 capsular types have been reported in Klebsiella spp., whereas capsular polysaccharide synthesis (cps) regions were available in only 22 types. Due to the limitations of serotyping, complete repertoire of cps will be helpful for capsular genotyping. We therefore resolved the rest 57 cps and conducted comparative analysis. Clustering results of 1,515 predicted proteins from cps loci categorized proteins which share similarity into homology groups (HGs) revealing that 77 Wzy polymerases were classified into 56 HGs, which indicate the high specificity of wzy between different types...
2015: Scientific Reports
Sara B Pereira, Rita Mota, Cristina P Vieira, Jorge Vieira, Paula Tamagnini
Many cyanobacteria produce extracellular polymeric substances (EPS) with particular characteristics (e.g. anionic nature and presence of sulfate) that make them suitable for industrial processes such as bioremediation of heavy metals or thickening, suspending or emulsifying agents. Nevertheless, their biosynthetic pathway(s) are still largely unknown, limiting their utilization. In this work, a phylum-wide analysis of genes/proteins putatively involved in the assembly and export of EPS in cyanobacteria was performed...
2015: Scientific Reports
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