scholarly journals Genetic and Biochemical Characterization of Salmonella enterica Serovar Typhi Deoxyribokinase

2000 ◽  
Vol 182 (4) ◽  
pp. 869-873 ◽  
Author(s):  
Lise Tourneux ◽  
Nadia Bucurenci ◽  
Cosmin Saveanu ◽  
Pierre Alexandre Kaminski ◽  
Madeleine Bouzon ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Biochemical Characterization ◽  
Site Directed Mutagenesis ◽  
Gene Encoding ◽  
E Coli ◽  
Salmonella Enterica Serovar Typhi ◽  
Acid Protein ◽  
Serovar Typhimurium ◽  
Amino Acid Protein

ABSTRACT We identified in the genome of Salmonella entericaserovar Typhi the gene encoding deoxyribokinase, deoK. Two other genes, vicinal to deoK, were determined to encode the putative deoxyribose transporter (deoP) and a repressor protein (deoQ). This locus, located between theuhpA and ilvN genes, is absent inEscherichia coli. The deoK gene inserted on a plasmid provides a selectable marker in E. coli for growth on deoxyribose-containing medium. Deoxyribokinase is a 306-amino-acid protein which exhibits about 35% identity with ribokinase from serovar Typhi, S. enterica serovar Typhimurium, or E. coli. The catalytic properties of the recombinant deoxyribokinase overproduced in E. colicorrespond to those previously described for the enzyme isolated from serovar Typhimurium. From a sequence comparison between serovar Typhi deoxyribokinase and E. coliribokinase, whose crystal structure was recently solved, we deduced that a key residue differentiating ribose and deoxyribose is Met10, which in ribokinase is replaced by Asn14. Replacement by site-directed mutagenesis of Met10 with Asn decreased theV max of deoxyribokinase by a factor of 2.5 and increased the K m for deoxyribose by a factor of 70, compared to the parent enzyme.

scholarly journals First Report of a Foodborne Salmonella enterica Serovar Gloucester (4:i:l,w) ST34 Strain Harboring blaCTX–M–55 and qnrS Genes Located in IS26-Mediated Composite Transposon

2021 ◽  
Vol 12 ◽  
Author(s):  
Lili Li ◽  
Rikke Heidemann Olsen ◽  
Anhua Song ◽  
Jian Xiao ◽  
Chong Wang ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Structural Unit ◽  
Bacterial Species ◽  
Meat Products ◽  
Sequence Type ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Long Read ◽  
Phenotypic And Genotypic Characterization

Extended-spectrum β-lactamases (ESBLs) production and (fluoro)quinolone (FQ) resistance among Salmonella pose a public health threat. The objective of this study was the phenotypic and genotypic characterization of an ESBL-producing and nalidixic acid-resistant Salmonella enterica serovar Gloucester isolate (serotype 4:i:l,w) of sequence type 34 (ST34) from ready-to-eat (RTE) meat products in China. Whole-genome short and long read sequencing (HiSeq and MinION) results showed that it contained blaCTX–M–55, qnrS1, and tetB genes, with blaCTX–M–55 and qnrS1 located in chromosomal IS26-mediated composite transposon (IS26–qnrS1–IS3–Tn3–orf–blaCTX–M–55–ISEcp1–IS26). The same genetic structure was found in the chromosome of S. enterica subsp. enterica serovar Typhimurium strain and in several plasmids of Escherichia coli, indicating that the IS26-mediated composite transposon in the chromosome of S. Gloucester may originate from plasmids of E. coli and possess the ability to disseminate to Salmonella and other bacterial species. Besides, the structural unit qnrS1–IS3–Tn3–orf–blaCTX–M–55 was also observed to be linked with ISKpn19 in both the chromosomes and plasmids of various bacteria species, highlighting the contribution of the insertion sequences (IS26 and ISKpn19) to the co-dissemination of blaCTX–M–55 and qnrS1. To our knowledge, this is the first description of chromosomal blaCTX–M–55 and qnrS in S. Gloucester from RTE meat products. Our work expands the host range and provides additional evidence of the co-transfer of blaCTX–M–55 and qnrS1 among different species of Salmonella through the food chain.

scholarly journals Aspartic Peptide Hydrolases in Salmonella enterica Serovar Typhimurium

2001 ◽  
Vol 183 (10) ◽  
pp. 3089-3097 ◽  
Author(s):  
Rachel A. Larsen ◽  
Tina M. Knox ◽  
Charles G. Miller
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Gene Encoding ◽  
E Coli ◽  
Mutant Strains ◽  
Serovar Typhimurium ◽  
Measurable Rate ◽  
Mature Enzyme ◽  
Aminopeptidase A ◽  
Peptide Hydrolases

ABSTRACT Two well-characterized enzymes in Salmonella entericaserovar Typhimurium and Escherichia coli are able to hydrolyze N-terminal aspartyl (Asp) dipeptides: peptidase B, a broad-specificity aminopeptidase, and peptidase E, an Asp-specific dipeptidase. A serovar Typhimurium strain lacking both of these enzymes, however, can still utilize most N-terminal Asp dipeptides as sources of amino acids, and extracts of such a strain contain additional enzymatic activities able to hydrolyze Asp dipeptides. Here we report two such activities from extracts of pepB pepEmutant strains of serovar Typhimurium identified by their ability to hydrolyze Asp-Leu. Although each of these activities hydrolyzes Asp-Leu at a measurable rate, the preferred substrates for both are N-terminal isoAsp peptides. One of the activities is a previously characterized isoAsp dipeptidase from E. coli, the product of theiadA gene. The other is the product of the serovar Typhimurium homolog of E. coli ybiK, a gene of previously unknown function. This gene product is a member of the N-terminal nucleophile structural family of amidohydrolases. Like most other members of this family, the mature enzyme is generated from a precursor protein by proteolytic cleavage and the active enzyme is a heterotetramer. Based on its ability to hydrolyze an N-terminal isoAsp tripeptide as well as isoAsp dipeptides, the enzyme appears to be an isoAsp aminopeptidase, and we propose that the gene encoding it be designated iaaA (isoAsp aminopeptidase). A strain lacking both IadA and IaaA in addition to peptidase B and peptidase E has been constructed. This strain utilizes Asp-Leu as a leucine source, and extracts of this strain contain at least one additional, as-yet-uncharacterized, peptidase able to cleave Asp dipeptides.

scholarly journals Inversions over the Terminus Region in Salmonella and Escherichia coli: IS200s as the Sites of Homologous Recombination Inverting the Chromosome of Salmonella enterica Serovar Typhi

2002 ◽  
Vol 184 (22) ◽  
pp. 6190-6197 ◽  
Author(s):  
Suneetha Alokam ◽  
Shu-Lin Liu ◽  
Kamal Said ◽  
Kenneth E. Sanderson
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Genome Structure ◽  
Enteric Bacteria ◽  
Genomic Rearrangements ◽  
Pcr Analysis ◽  
E Coli ◽  
Salmonella Enterica Serovar Typhi ◽  
Serovar Typhimurium ◽  
Type Strains

ABSTRACT Genomic rearrangements (duplications and inversions) in enteric bacteria such as Salmonella enterica serovar Typhimurium LT2 and Escherichia coli K12 are frequent (10−3 to 10−5) in culture, but in wild-type strains these genomic rearrangements seldom survive. However, inversions commonly survive in the terminus of replication (TER) region, where bidirectional DNA replication terminates; nucleotide sequences from S. enterica serovar Typhimurium LT2, S. enterica serovar Typhi CT18, E. coli K12, and E. coli O157:H7 revealed genomic inversions spanning the TER region. Assuming that S. enterica serovar Typhimurium LT2 represents the ancestral genome structure, we found an inversion of 556 kb in serovar Typhi CT18 between two of the 25 IS200 elements and an inversion of about 700 kb in E. coli K12 and E. coli O157:H7. In addition, there is another inversion of 500 kb in E. coli O157:H7 compared with E. coli K12. PCR analysis confirmed that all S. enterica serovar Typhi strains tested, but not strains of other Salmonella serovars, have an inversion at the exact site of the IS200 insertions. We conclude that inversions of the TER region survive because they do not significantly change replication balance or because they are part of the compensating mechanisms to regain chromosome balance after it is disrupted by insertions, deletions, or other inversions.

scholarly journals Molecular Cloning and Biochemical Characterization of a Recombinant Sterol 3-O-Glucosyltransferase fromGymnema sylvestreR.Br. Catalyzing Biosynthesis of Steryl Glucosides

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Pragya Tiwari ◽  
Rajender Singh Sangwan ◽  
Asha ◽  
B. N. Mishra ◽  
Farzana Sabir ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Present Report ◽  
Hydroxyl Group ◽  
Biological Origin ◽  
Reading Frame ◽  
Steryl Glucosides ◽  
Acid Protein ◽  
Phytochemical Profiles ◽  
Amino Acid Protein

Gymnema sylvestreR.Br., a pharmacologically important herb vernacularly called Gur-Mar (sugar eliminator), is widely known for its antidiabetic action. This property of the herb has been attributed to the presence of bioactive triterpene glycosides. Although some information regarding pharmacology and phytochemical profiles of the plant are available, no attempts have been made so far to decipher the biosynthetic pathway and key enzymes involved in biosynthesis of steryl glucosides. The present report deals with the identification and catalytic characterization of a glucosyltransferase, catalyzing biosynthesis of steryl glycosides. The full length cDNA (2572 bp) contained an open reading frame of 2106 nucleotides that encoded a 701 amino acid protein, falling into GT-B subfamily of glycosyltransferases. The GsSGT was expressed inEscherichia coliand biochemical characterization of the recombinant enzyme suggested its key role in the biosynthesis of steryl glucosides with catalytic preference for C-3 hydroxyl group of sterols. To our knowledge, this pertains to be the first report on cloning and biochemical characterization of a sterol metabolism gene fromG. sylvestreR.Br. catalyzing glucosylation of a variety of sterols of biological origin from diverse organisms such as bacteria, fungi, and plants.

Characterization of the micA gene encoding a small regulatory σE-dependent RNA in Salmonella enterica serovar Typhimurium

2011 ◽  
Vol 56 (1) ◽  
pp. 59-65 ◽  
Author(s):  
D. Homerova ◽  
B. Rezuchova ◽  
A. Stevenson ◽  
H. Skovierova ◽  
M. Roberts ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Gene Encoding ◽  
Mica Gene ◽  
Serovar Typhimurium

scholarly journals A Gene Encoding l-Methionine γ-Lyase Is Present in Enterobacteriaceae Family Genomes: Identification and Characterization of Citrobacter freundiil-Methionine γ-Lyase

2005 ◽  
Vol 187 (11) ◽  
pp. 3889-3893 ◽  
Author(s):  
Ilya V. Manukhov ◽  
Daria V. Mamaeva ◽  
Sergei M. Rastorguev ◽  
Nicolai G. Faleev ◽  
Elena A. Morozova ◽  
...  
Keyword(s):  
Shigella Flexneri ◽  
Open Reading Frames ◽  
Gene Encoding ◽  
High Sequence Identity ◽  
E Coli ◽  
The Family ◽  
Serovar Typhimurium ◽  
Identification And Characterization ◽  
Reading Frames

ABSTRACT Citrobacter freundii cells produce l-methionine γ-lyase when grown on a medium containing l-methionine. The nucleotide sequence of the hybrid plasmid with a C. freundii EcoRI insert of about 3.0 kbp contained two open reading frames, consisting of 1,194 nucleotides and 1,296 nucleotides, respectively. The first one (denoted megL) encoded l-methionine γ-lyase. The enzyme was overexpressed in Escherichia coli and purified. The second frame encoded a protein belonging to the family of permeases. Regions of high sequence identity with the 3′-terminal part of the C. freundii megL gene located in the same regions of Salmonella enterica serovar Typhimurium, Shigella flexneri, E. coli, and Citrobacter rodentium genomes were found.

scholarly journals Acquisition of the rfb-gnd Cluster in Evolution of Escherichia coli O55 and O157

2000 ◽  
Vol 182 (21) ◽  
pp. 6183-6191 ◽  
Author(s):  
Phillip I. Tarr ◽  
Laura M. Schoening ◽  
Yoo-Lee Yea ◽  
Teresa R. Ward ◽  
Srdjan Jelacic ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Side Chains ◽  
Gene Encoding ◽  
Gram Negative ◽  
E Coli ◽  
Phosphogluconate Dehydrogenase ◽  
Serovar Typhimurium ◽  
Polymorphic Gene ◽  
O Antigens

ABSTRACT The rfb region specifies the structure of lipopolysaccharide side chains that comprise the diverse gram-negative bacterial somatic (O) antigens. The rfb locus is adjacent to gnd, which is a polymorphic gene encoding 6-phosphogluconate dehydrogenase. To determine if rfb andgnd cotransfer, we sequenced gnd in five O55 and 13 O157 strains of Escherichia coli. E. coli O157:H7 has a gnd allele (allele A) that is only 82% identical to the gnd allele (alleleD) of closely related E. coli O55:H7. In contrast, gnd alleles of E. coli O55 in distant lineages are >99.9% identical to gnd alleleD. Though gnd alleles B andC in E. coli O157 that are distantly related toE. coli O157:H7 are more similar to allele Athan to allele D, there are nucleotide differences at 4 to 6% of their sites. Alleles B and C can be found in E. coli O157 in different lineages, but we have found allele A only in E. coli O157 belonging to the DEC5 lineage. DNA 3′ to the O55 gnd allele in diverse E. coli lineages has sequences homologous totnpA of the Salmonella enterica serovar Typhimurium IS200 element, E. coli Rhs elements (including an H-rpt gene), and portions of the O111 and O157rfb regions. We conclude that rfb andgnd cotransferred into E. coli O55 and O157 in widely separated lineages and that recombination was responsible for recent antigenic shifts in the emergence of pathogenic E. coli O55 and O157.

scholarly journals Functional Characterization of the Initiation Enzyme of S-Layer Glycoprotein Glycan Biosynthesis in Geobacillus stearothermophilus NRS 2004/3a

2007 ◽  
Vol 189 (7) ◽  
pp. 2590-2598 ◽  
Author(s):  
Kerstin Steiner ◽  
René Novotny ◽  
Kinnari Patel ◽  
Evgenij Vinogradov ◽  
Chris Whitfield ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Biochemical Characterization ◽  
Functional Characterization ◽  
Geobacillus Stearothermophilus ◽  
Polysaccharide Biosynthesis ◽  
Glycan Chain ◽  
Galactose Residue ◽  
Serovar Typhimurium

ABSTRACTThe glycan chain of the S-layer glycoprotein ofGeobacillus stearothermophilusNRS 2004/3a is composed of repeating units [→2)-α-l-Rhap-(1→3)-β-l-Rhap-(1→2)-α-l-Rhap-(1→], with a 2-O-methyl modification of the terminal trisaccharide at the nonreducing end of the glycan chain, a core saccharide composed of two or three α-l-rhamnose residues, and a β-d-galactose residue as a linker to the S-layer protein. In this study, we report the biochemical characterization of WsaP of the S-layer glycosylation gene cluster as a UDP-Gal:phosphoryl-polyprenol Gal-1-phosphate transferase that primes the S-layer glycoprotein glycan biosynthesis ofGeobacillus stearothermophilusNRS 2004/3a. Our results demonstrate that the enzyme transfers in vitro a galactose-1-phosphate from UDP-galactose to endogenous phosphoryl-polyprenol and that the C-terminal half of WsaP carries the galactosyltransferase function, as already observed for the UDP-Gal:phosphoryl-polyprenol Gal-1-phosphate transferase WbaP fromSalmonella enterica. To confirm the function of the enzyme, we show that WsaP is capable of reconstituting polysaccharide biosynthesis in WbaP-deficient strains ofEscherichia coliandSalmonella entericaserovar Typhimurium.

Characterization of the multidrug efflux transporter styMdtM from Salmonella enterica serovar Typhi

2021 ◽  
Author(s):  
Aqsa Shaheen ◽  
Fouzia Ismat ◽  
Mazhar Iqbal ◽  
Abdul Haque ◽  
Zaheer Ul‐Haq ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Efflux Transporter ◽  
Multidrug Efflux ◽  
Salmonella Enterica Serovar Typhi
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