Showing papers by "Lei Wang published in 2011"
TL;DR: This study will facilitate the identification of pathogenicity-related genes and provide a broad foundation for understanding the molecular and evolutionary mechanisms underlying fungi-nematodes interactions.
Abstract: Nematode-trapping fungi are “carnivorous” and attack their hosts using specialized trapping devices. The morphological development of these traps is the key indicator of their switch from saprophytic to predacious lifestyles. Here, the genome of the nematode-trapping fungus Arthrobotrys oligospora Fres. (ATCC24927) was reported. The genome contains 40.07 Mb assembled sequence with 11,479 predicted genes. Comparative analysis showed that A. oligospora shared many more genes with pathogenic fungi than with non-pathogenic fungi. Specifically, compared to several sequenced ascomycete fungi, the A. oligospora genome has a larger number of pathogenicity-related genes in the subtilisin, cellulase, cellobiohydrolase, and pectinesterase gene families. Searching against the pathogen-host interaction gene database identified 398 homologous genes involved in pathogenicity in other fungi. The analysis of repetitive sequences provided evidence for repeat-induced point mutations in A. oligospora. Proteomic and quantitative PCR (qPCR) analyses revealed that 90 genes were significantly up-regulated at the early stage of trap-formation by nematode extracts and most of these genes were involved in translation, amino acid metabolism, carbohydrate metabolism, cell wall and membrane biogenesis. Based on the combined genomic, proteomic and qPCR data, a model for the formation of nematode trapping device in this fungus was proposed. In this model, multiple fungal signal transduction pathways are activated by its nematode prey to further regulate downstream genes associated with diverse cellular processes such as energy metabolism, biosynthesis of the cell wall and adhesive proteins, cell division, glycerol accumulation and peroxisome biogenesis. This study will facilitate the identification of pathogenicity-related genes and provide a broad foundation for understanding the molecular and evolutionary mechanisms underlying fungi-nematodes interactions.
240 citations
TL;DR: This study provides the first draft genome and comprehensive lipid profile for M. alpina, and lays the foundation for possible genetic engineering of M.Alpina to produce higher levels and diverse contents of dietary lipids.
Abstract: Mortierella alpina is an oleaginous fungus which can produce lipids accounting for up to 50% of its dry weight in the form of triacylglycerols. It is used commercially for the production of arachidonic acid. Using a combination of high throughput sequencing and lipid profiling, we have assembled the M. alpina genome, mapped its lipogenesis pathway and determined its major lipid species. The 38.38 Mb M. alpina genome shows a high degree of gene duplications. Approximately 50% of its 12,796 gene models, and 60% of genes in the predicted lipogenesis pathway, belong to multigene families. Notably, M. alpina has 18 lipase genes, of which 11 contain the class 2 lipase domain and may share a similar function. M. alpina's fatty acid synthase is a single polypeptide containing all of the catalytic domains required for fatty acid synthesis from acetyl-CoA and malonyl-CoA, whereas in many fungi this enzyme is comprised of two polypeptides. Major lipids were profiled to confirm the products predicted in the lipogenesis pathway. M. alpina produces a complex mixture of glycerolipids, glycerophospholipids and sphingolipids. In contrast, only two major sterol lipids, desmosterol and 24(28)-methylene-cholesterol, were detected. Phylogenetic analysis based on genes involved in lipid metabolism suggests that oleaginous fungi may have acquired their lipogenic capacity during evolution after the divergence of Ascomycota, Basidiomycota, Chytridiomycota and Mucoromycota. Our study provides the first draft genome and comprehensive lipid profile for M. alpina, and lays the foundation for possible genetic engineering of M. alpina to produce higher levels and diverse contents of dietary lipids.
140 citations
TL;DR: These are the first direct measurements for a clone in a well-defined host community that includes rates of mutation and host transmission of a uropathogenic E. coli clone that persisted for 3 years within a household, including a dog, causing a urinary tract infection in the dog after 2 years.
Abstract: Although over 50 complete Escherichia coli/Shigella genome sequences are available, it is only for closely related strains, for example the O55:H7 and O157:H7 clones of E. coli, that we can assign differences to individual evolutionary events along specific lineages. Here we sequence the genomes of 14 isolates of a uropathogenic E. coli clone that persisted for 3 years within a household, including a dog, causing a urinary tract infection (UTI) in the dog after 2 years. The 20 mutations observed fit a single tree that allows us to estimate the mutation rate to be about 1.1 per genome per year, with minimal evidence for adaptive change, including in relation to the UTI episode. The host data also imply at least 6 host transfer events over the 3 years, with 2 lineages present over much of that period. To our knowledge, these are the first direct measurements for a clone in a well-defined host community that includes rates of mutation and host transmission. There is a concentration of non-synonymous mutations associated with 2 transfers to the dog, suggesting some selection pressure from the change of host. However, there are no changes to which we can attribute the UTI event in the dog, which suggests that this occurrence after 2 years of the clone being in the household may have been due to chance, or some unknown change in the host or environment. The ability of a UTI strain to persist for 2 years and also to transfer readily within a household has implications for epidemiology, diagnosis, and clinical intervention.
115 citations
TL;DR: The complete genome of deep-sea sedimentary bacterium SM9913 is described and compared with that of the closely related Antarctic surface sea-water ecotype Pseudoalteromonas haloplanktis TAC125, indicating a possible sensitivity to reactive oxygen species.
Abstract: Deep-sea sediment is one of the most important microbial-driven ecosystems, yet it is not well characterized. Genome sequence analyses of deep-sea sedimentary bacteria would shed light on the understanding of this ecosystem. In this study, the complete genome of deep-sea sedimentary bacterium Pseudoalteromonas sp. SM9913 (SM9913) is described and compared with that of the closely related Antarctic surface sea-water ecotype Pseudoalteromonas haloplanktis TAC125 (TAC125). SM9913 has fewer dioxygenase genes than TAC125, indicating a possible sensitivity to reactive oxygen species. Accordingly, experimental results showed that SM9913 was less tolerant of H2O2 than TAC125. SM9913 has gene clusters related to both polar and lateral flagella biosynthesis. Lateral flagella, which are usually present in deep-sea bacteria and absent in the related surface bacteria, are important for the survival of SM9913 in deep-sea environments. With these two flagellar systems, SM9913 can swim in sea water and swarm on the sediment particle surface, favoring the acquisition of nutrients from particulate organic matter and reflecting the particle-associated alternative lifestyle of SM9913 in the deep sea. A total of 12 genomic islands were identified in the genome of SM9913 that may confer specific features unique to SM9913 and absent from TAC125, such as drug and heavy metal resistance. Many signal transduction genes and a glycogen production operon were also present in the SM9913 genome, which may help SM9913 respond to food pulses and store carbon and energy in a deep-sea environment.
103 citations
TL;DR: The complete genome sequence of ST-III, a probiotic strain with several functions, was isolated from kimchi and compared with two published L. plantarum genomes.
Abstract: Lactobacillus plantarum strain ST-III, a probiotic strain with several functions, was isolated from kimchi. Here we report the complete genome sequence of ST-III and compared it with two published L. plantarum genomes.
87 citations
TL;DR: The complete genome sequence of Aeromonas veronii strain B565 is presented and represents an independent stepwise acquisition of virulence factors of pathogenic strains in this genus.
Abstract: Aeromonas veronii strain B565 was isolated from aquaculture pond sediment in China. We present here the complete genome sequence of B565 and compare it with 2 published genome sequences of pathogenic strains in the Aeromonas genus. The result represents an independent stepwise acquisition of virulence factors of pathogenic strains in this genus.
70 citations
TL;DR: The complete genome sequence of ND03 is presented and it is compared to three other published genomes of Streptococcus thermophilus strains to compare it to.
Abstract: Streptococcus thermophilus strain ND03 is a Chinese commercial dairy starter used for the manufacture of yogurt. It was isolated from naturally fermented yak milk in Qinghai, China. We present here the complete genome sequence of ND03 and compare it to three other published genomes of Streptococcus thermophilus strains.
67 citations
TL;DR: The serotype scheme presented here could prove to be a useful tool for serotyping C. sakazakii isolates and characterized the O-antigen gene clusters using restriction fragment length polymorphism (RFLP).
Abstract: Cronobacter sakazakii is an opportunistic pathogen that can cause severe infections. Serotyping provides a basis for the categorization of bacterial strains and is an important tool for epidemiological and surveillance purposes. In this study, of the 135 Cronobacter strains tested initially, 119 were identified as C. sakazakii and used. A serotyping scheme for C. sakazakii that classifies strains based on their different O antigens was developed. Seven antisera that exhibited high agglutinin titers (>640) were produced. O2 and O6 antisera were specific for their homologous strains, O4 and O7 antisera gave heterologous titers with O1 and O6 antigens, respectively, and O1, O3, and O5 antisera cross-reacted with each other and require preabsorption with the other two antigens. All of these 119 C. sakazakii strains were clearly assigned to these seven serotypes. O1 and O2 are the dominant serotypes, comprising 69.7% of the isolates. We also characterized the O-antigen gene clusters using restriction fragment length polymorphism (RFLP). The grouping of C. sakazakii strains based on their RFLP banding patterns correlated well with the grouping of strains based on our serotyping scheme. The serotype scheme presented here could prove to be a useful tool for serotyping C. sakazakii isolates.
64 citations
TL;DR: A finished, annotated, and compared 4.14-Mbp high-quality genome sequence of B. megaterium WSH-002, which is the companion strain for Ketogulonicigenium vulgare in the vitamin C industry and is stocked in the authors' laboratory.
Abstract: Bacillus megaterium, an industrial strain, has been widely used in protein production and the vitamin C industry. Here we reported a finished, annotated, and compared 4.14-Mbp high-quality genome sequence of B. megaterium WSH-002, which is the companion strain for Ketogulonicigenium vulgare in the vitamin C industry and is stocked in our laboratory.
52 citations
TL;DR: The complete genome sequence of M. hyopneumoniae strain 168 is announced, a pathogenic strain prevalent in China that was isolated in 1974 and had not been determined.
Abstract: Mycoplasma hyopneumoniae strain 168, a pathogenic strain prevalent in China, was isolated in 1974. Although this strain has been widespread for a long time, the genome sequence had not been determined. Here, we announce the complete genome sequence of M. hyopneumoniae strain 168.
51 citations
TL;DR: An oligonucleotide-based microarray using the sequences of 16S-23S rDNA internal transcribed spacer regions (ITS) and the gyrase subunit B gene (gyrB) found in the most prevalent and devastating waterborne pathogenic agents is developed.
TL;DR: The comparative genome analysis indicates that these two strains may have attained their pathogenicity by completely separate evolutionary events, and the 105.5R(r) strain, a representative of the Old World biogroup, lies in a branch of Y. enterocolitica that is distinct from the “New World” 8081 strain.
Abstract: Yersinia enterocolitica is a heterogeneous bacterial species with a wide range of animal reservoirs through which human intestinal illness can be facilitated. In contrast to the epidemiological pattern observed in the United States, infections in China present a pattern similar to those in European countries and Japan, wherein “Old World” strains (biotypes 2 to 5) are prevalent. To gain insights into the evolution of Y. enterocolitica and pathogenic properties toward human hosts, we sequenced the genome of a biotype 3 strain, 105.5R(r) (O:9), obtained from a Chinese patient. Comparative genome sequence analysis with strain 8081 (1B/O:8) revealed new insights into Y. enterocolitica. Both strains have more than 14% specific genes. In strain 105.5R(r), putative virulence factors were found in strain-specific genomic pathogenicity islands that comprised a novel type III secretion system and rtx-like genes. Many of the loci representing ancestral clusters, which are believed to contribute to enteric survival and pathogenesis, are present in strain 105.5R(r) but lost in strain 8081. Insertion elements in 105.5R(r) have a pattern distinct from those in strain 8081 and were exclusively located in a strain-specific region. In summary, our comparative genome analysis indicates that these two strains may have attained their pathogenicity by completely separate evolutionary events, and the 105.5R(r) strain, a representative of the Old World biogroup, lies in a branch of Y. enterocolitica that is distinct from the “New World” 8081 strain.
TL;DR: The whole genome of strain H10 was sequenced and it was compared to the published genome sequence of Lactobacillus helveticus DPC4571 to show correspondence between the two strains.
Abstract: Lactobacillus helveticus strain H10 was isolated from traditional fermented milk in Tibet, China. We sequenced the whole genome of strain H10 and compared it to the published genome sequence of Lactobacillus helveticus DPC4571.
TL;DR: The complete genome sequence of LC2W is presented and the identification of a gene cluster implicated in the biosynthesis of exopolysaccharides is identified.
Abstract: Lactobacillus casei LC2W, a patented probiotic strain (Z. Wu, European patent EP 1642963 B1, February 2009), has been isolated from Chinese traditional dairy products and implemented in industrial production as starter culture. Here we present the complete genome sequence of LC2W and the identification of a gene cluster implicated in the biosynthesis of exopolysaccharides.
TL;DR: The main genome features of ND02 and several differences with two other published genomes of Lactobacillus delbrueckii subsp.
Abstract: Lactobacillus delbrueckii subsp. bulgaricus strain ND02 is a Chinese commercial dairy starter used for the manufacture of yoghurt. It was isolated from naturally fermented yak milk in Qinghai, China. Here, we report the main genome features of ND02 and several differences with two other published genomes of Lactobacillus delbrueckii subsp. bulgaricus strains.
TL;DR: The finished, annotated, and compared 3.28-Mbp high-quality genome sequence of Ketogulonicigenium vulgare WSH-001, a 2-keto-l-gulonic acid-producing industrial strain stocked in the laboratory is reported.
Abstract: Ketogulonicigenium vulgare is an industrial organism commonly used in the vitamin C industry. Here, we report the finished, annotated, and compared 3.28-Mbp high-quality genome sequence of Ketogulonicigenium vulgare WSH-001, a 2-keto-l-gulonic acid-producing industrial strain stocked in our laboratory.
TL;DR: The complete genome sequence of BD-II, a patented probiotic strain isolated from homemade koumiss in China, shows high similarity with the well-studied probiotic BL23.
Abstract: Lactobacillus casei BD-II, a patented probiotic strain (U.S. patent 7,270,994 B2), was isolated from homemade koumiss in China and has been implemented in the industrial production as starter cultures. Here we report the complete genome sequence of BD-II, which shows high similarity with the well-studied probiotic BL23.
TL;DR: Analysis of metabolic and protein–protein interactions networks through integration of transcriptional and metabolic profiles predicted correlations of genes involved in glycolysis, the tricarboxylic acid cycle, gluconeogenesis, sugar uptake, amino acid metabolism, and fatty acid β-oxidation.
Abstract: Xylose is the second most abundant lignocellulosic component besides glucose, but it cannot be fermented by the widely used ethanol-producing yeast Saccharomyces cerevisiae. The yeast Scheffersomyces stipitis, however, is well known for its high native capacity to ferment xylose. Here, we applied next-generation sequencing technology for RNA (RNA-Seq) to generate two high-resolution transcriptional maps of the S. stipitis genome when this yeast was grown using glucose or xylose as the sole carbon source. RNA-Seq revealed that 5,176 of 5,816 annotated open reading frames had a uniform transcription and that 214 open reading frames were differentially transcribed. Differential expression analysis showed that, compared with other biological processes, carbohydrate metabolism and oxidation-reduction reactions were highly enhanced in yeast grown on xylose. Measurement of metabolic indicators of fermentation showed that, in yeast grown on xylose, the concentrations of cysteine and ornithine were twofold higher and the concentrations of unsaturated fatty acids were also increased. Analysis of metabolic profiles coincided with analysis of certain differentially expressed genes involved in metabolisms of amino acid and fatty acid. In addition, we predicted protein–protein interactions of S. stipitis through integration of gene orthology and gene expression. Further analysis of metabolic and protein–protein interactions networks through integration of transcriptional and metabolic profiles predicted correlations of genes involved in glycolysis, the tricarboxylic acid cycle, gluconeogenesis, sugar uptake, amino acid metabolism, and fatty acid β-oxidation. Our study reveals potential target genes for xylose fermentation improvement and provides insights into the mechanisms underlying xylose fermentation in S. stipitis.
TL;DR: The complete genome sequence of Staphylococcus aureus T0131 is reported, which is a multiresistant clinical isolate recovered in China and the first sequenced epidemic ST239-MRSA-SCCmec type III strain obtained in Asia.
Abstract: We report here the complete genome sequence of Staphylococcus aureus T0131, which is a multiresistant clinical isolate recovered in China and the first sequenced epidemic ST239-MRSA-SCCmec type III strain obtained in Asia. Comparison with two published genomes of ST239 reveals the polymorphism among strains of this type from different continents.
TL;DR: The genome sequence of Bordetella pertussis strain CS, isolated from an infant patient in Beijing and widely used as a vaccine strain for production of an acellular pertussedis vaccine in China, is reported.
Abstract: Bordetella pertussis is the causative agent of pertussis. Here, we report the genome sequence of Bordetella pertussis strain CS, isolated from an infant patient in Beijing and widely used as a vaccine strain for production of an acellular pertussis vaccine in China.
TL;DR: The DNA microarray method described in this communication is specific, sensitive, and reliable and has several advantages over traditional methods of bacterial culture and antiserum agglutination assays.
Abstract: We established a microarray for the simultaneous detection and identification of diverse putative pathogens often associated with fishery products by targeting specific genes of Listeria monocytogenes, Salmonella, Shigella, Staphylococcus aureus, Streptococcus pyogenes, Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus, and Yersinia enterocolitica and the 16S-23S rRNA gene internal transcribed spacer (ITS) region of Proteus mirabilis and Proteus vulgaris. The microarray contained 26 specific probes and was tested against a total of 123 target bacterial strains that included 55 representative strains, 68 clinical isolates, and 45 strains of other bacterial species that belonged to 8 genera and 34 species, and it was shown to be specific and reproducible. A detection sensitivity of 10 ng DNA or 10 CFU/ml for pure cultures of each target organism demonstrated that the assay was highly sensitive and reproducible. Mock and real fishery product samples were tested by the microarray, and the accuracy was 100%. The DNA microarray method described in this communication is specific, sensitive, and reliable and has several advantages over traditional methods of bacterial culture and antiserum agglutination assays.
TL;DR: This study is the first to report the comprehensive characterization of a BH₄ biosynthesis pathway in a fungus, reflecting the unique ability of this fungus to synthesize both BH ₄ and folate, using the GTPCH product as a common substrate.
Abstract: We characterized the de novo biosynthetic pathway of tetrahydrobiopterin (BH4) in the lipid-producing fungus Mortierella alpina. The BH4 cofactor is essential for various cell processes, and is probably present in every cell or tissue of higher organisms. Genes encoding two copies of GTP cyclohydrolase I (GTPCH-1 and GTPCH-2) for the conversion of GTP to dihydroneopterin triphosphate (H2-NTP), 6-pyruvoyltetrahydropterin synthase (PTPS) for the conversion of H2-NTP to 6-pyruvoyltetrahydropterin (PPH4), and sepiapterin reductase (SR) for the conversion of PPH4 to BH4, were expressed heterologously in Escherichia coli. The recombinant enzymes were produced as His-tagged fusion proteins and were purified to homogeneity to investigate their enzymic activities. Enzyme products were analysed by HPLC and electrospray ionization-MS. Kinetic parameters and other properties of GTPCH, PTPS and SR were investigated. Physiological roles of BH4 in M. alpina are discussed, and comparative analyses between GTPCH, PTPS and SR proteins and other homologous proteins were performed. The presence of two functional GTPCH enzymes has, as far as we are aware, not been reported previously, reflecting the unique ability of this fungus to synthesize both BH4 and folate, using the GTPCH product as a common substrate. To our knowledge, this study is the first to report the comprehensive characterization of a BH4 biosynthesis pathway in a fungus.
TL;DR: The data reported here demonstrate that the multiplex PCR method described is efficient and convenient for the detection of Legionella species in water samples and was shown to be highly specific and reproducible when tested against 41 target strains and 17 strains of other bacteria species.
Abstract: A total of 25 gyrB gene sequences from 20 Legionella pneumophila subsp. pneumophila strains and five L. pneumophila subsp. fraseri strains were obtained and analyzed, and a multiplex PCR for the simultaneous detection of Legionella bozemanae, Legionella longbeachae, Legionella micdadei and Legioenella pneumophila, and two single PCRs for the differentiation of L. pneumophila subsp. pneumophila and L. pneumophila subsp. fraseri were established. The multiplex PCR method was shown to be highly specific and reproducible when tested against 41 target strains and 17 strains of other bacteria species. The sensitivity of the multiplex PCR was also analyzed and was shown to detect levels as low as 1 ng of genomic DNA or 10 colony-forming units (CFUs) per milliliter in mock water samples. Sixty-three air conditioner condensed water samples from Shanghai City were examined, and the result was validated using 16S rRNA sequencing. The data reported here demonstrate that the multiplex PCR method described is efficient and convenient for the detection of Legionella species in water samples. Twenty L. pneumophila subsp. pneumophila strains and five L. pneumophila subsp. fraseri strains were used for the validation of the two L. pneumophila subspecies-specific PCR methods, and the results indicated that the two PCR methods were both highly specific and convenient for the identification of L. pneumophila at the subspecies level.
TL;DR: A novel 38-kb conjugative plasmid, pO157_Sal, was identified and sequenced from an Escherichia coli O157:H7 outbreak-associated Chinese isolate that shares high similarity with a plasmids in Salmonella enterica serovar Agona.
Abstract: In addition to the large virulence plasmid pO157, a novel 38-kb conjugative plasmid, pO157_Sal, was identified and sequenced from an Escherichia coli O157:H7 outbreak-associated Chinese isolate that shares high similarity with a plasmid in Salmonella enterica serovar Agona. The plasmid was found in 15 of 326 isolates, 12 of which were of the same pulsed-field gel electrophoresis type.
TL;DR: A previously undefined pair of Escherichia coli and Salmonella enterica with closely related O-antigens is reported on, which can be used for development of PCR-based assays for identification and detection of E. coli O85 strains.
Abstract: O-Antigen is a part of the lipopolysaccharide present in the outer membrane of Gram-negative bacteria, which confers major antigenic variability to the cell surface. In this study, we report on a previously undefined pair of Escherichia coli and Salmonella enterica with closely related O-antigens. The O-polysaccharides were isolated from the lipopolysaccharides of E. coli O85 and S. enterica O17 by mild acid degradation and studied by sugar analysis and NMR spectroscopy. The following structure was established for the O-unit of the E. coli O85-polysaccharide: The S. enterica O17-polysaccharide has the same carbohydrate backbone and, in addition, contains an O-acetyl group at position 2 of ~80% β-Galf residues. The O-antigen gene cluster of E. coli O85 was found to be closely related to that of S. enterica O17. Screening of type strains of all E. coli and S. enterica O-serogroups revealed two genes specific to the E. coli O85 O-antigen gene cluster, which can be used for development of PCR-based assays for identification and detection of E. coli O85 strains.
TL;DR: The O-specific polysaccharide from the lipopolysaccharides of Cronobacter sakazakii G2592 was studied by sugar analysis along with 1D and 2D (1)H and (13)C NMR spectroscopy, and the following structure of the pentasaccharide repeating unit was established.
TL;DR: The results of this investigation suggest possible anti‐cancer mechanisms of the ZLJ tablet, and lay a foundation to further analyse its therapeutic roles.
Abstract: Zilongjin (ZLJ) tablet, which is a traditional Chinese medicine, has been approved as a new anti-tumor drug by the State Food and Drug Administration of China; however, its anti-cancer mechanisms remain elusive. The goal of this study was to investigate the underlying anti-cancer activities of ZLJ tablet in vitro. In this study, four lung cancer cell lines, A549, H446, H460 and H520, were treated with 2.2 mg/mL of ZLJ solution for 24 h at 37 °C under 5% CO2. RNA was isolated and a microarray experiment using the Affymetrix Human Genome U133 plus 2.0 Array was employed to differentiate the expression patterns of cancer-related genes after drug treatment. Of 483 genes in 63 functional categories and 25 different pathways that showed at least a 2-fold change of expression level in the four cancer cell lines, 170 genes were upregulated, and 313 genes were downregulated. Eleven of the 483 genes were cancer-related and belong to the three known pathways: apoptosis, cell cycle regulation and mitogen-activated protein kinase (MAPK) cascade. The microarray data were validated by real-time RT-PCR. The results of this investigation suggest possible anti-cancer mechanisms of the ZLJ tablet, and lay a foundation to further analyse its therapeutic roles. Copyright © 2011 John Wiley & Sons, Ltd.
TL;DR: The O-antigen is a part of the lipopolysaccharide molecule present in the outer membrane of Gram-negative bacteria, and is essential for the full function of the microorganisms, and the degree of relatedness between the O-antsigens of S. enterica and E. coli was underestimated.
Abstract: The O-antigen is a part of the lipopolysaccharide molecule present in the outer membrane of Gram-negative bacteria, and is essential for the full function of the microorganisms. Salmonella enterica and Escherichia coli are taxonomically closely related species. In this study, the O-antigen structures of S. enterica O16 and O38 and E. coli O11 were determined. Salmonella enterica O38 and E. coli O21 were found to have identical O-antigen structures, whereas S. enterica O16 and E. coli O11 had closely related structures, differing only in the presence of a lateral glucose residue and O-acetylation of a mannose residue in the former. The O-antigen gene clusters of S. enterica O16 and O38 and E. coli O11 were sequenced and analyzed together with that of E. coli O21 retrieved from the GenBank. Each S. enterica/E. coli pair was found to contain the same set of genes organized in the same manner and to share 56-78% overall DNA identity. These data suggest that the O-antigen gene clusters of each pair studied originated from a common ancestor. Thus, it has become evident that in the past, the degree of relatedness between the O-antigens of S. enterica and E. coli was underestimated.
TL;DR: The O-polysaccharide of Salmonella enterica O59 was studied using sugar analysis and 2D (1)H and (13)C NMR spectroscopy, and the following structure of the tetrasaccharide repeating unit was established.
TL;DR: The O-polysaccharide (O-antigen) of Salmonella enterica O53 was isolated by mild acid degradation of the lipopolysaccharides and studied by sugar analysis and (1)H and (13)C NMR spectroscopy before and after O-deacetylation.