scholarly journals Mutation at the “Exit Gate” of the Salmonella Gyrase A Subunit Suppresses a Defect in the Gyrase B Subunit

2005 ◽  
Vol 187 (19) ◽  
pp. 6841-6844 ◽  
Author(s):  
Anne-Béatrice Blanc-Potard ◽  
Gilles Labesse ◽  
Nara Figueroa-Bossi ◽  
Lionello Bossi
Keyword(s):  
Nalidixic Acid ◽  
Salmonella Enterica ◽  
Dimer Interface ◽  
B Subunit ◽  
Modeling Analysis ◽  
Serovar Typhimurium ◽  
Gyrase A ◽  
A Subunit ◽  
Selection For ◽  
Novobiocin Resistance

ABSTRACT In Salmonella enterica serovar Typhimurium, an S431P substitution in the B subunit of gyrase (allele gyrB651) confers resistance to nalidixic acid and causes reduced DNA superhelicity and hypersensitivity to novobiocin. Selection for novobiocin resistance allowed isolation of a mutation in the gyrA gene (allele gyrA659), a T467S substitution, which partially suppresses the supercoiling defect of gyrB651. Modeling analysis suggests that this mutation acts by destabilizing the GyrA bottom dimer interface. This is the first example of a gyrA mutation that compensates for a gyrB defect.

scholarly journals Draft Genome Sequences of 19 Salmonella enterica Serovar Typhimurium [4,5:i:−] Strains Resistant to Nalidixic Acid from a Long-Term Outbreak in Italy: TABLE 1 

2015 ◽  
Vol 3 (4) ◽  
Author(s):  
Massimiliano Orsini ◽  
Iolanda Mangone ◽  
Adriano DiPasquale ◽  
Samuel Perticara ◽  
Lorena Sacchini ◽  
...  
Keyword(s):  
Nalidixic Acid ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Draft Genome ◽  
Central Italy ◽  
Genome Sequences ◽  
Serovar Typhimurium

Here, we present the draft genome sequences of 19 Salmonella enterica serovar Typhimurium monophasic variant [4,5:i:−] strains involved in a long-term salmonellosis outbreak that occurred in central Italy in 2013 to 2014.

scholarly journals Mapping Simocyclinone D8 Interaction with DNA Gyrase: Evidence for a New Binding Site on GyrB

2009 ◽  
Vol 54 (1) ◽  
pp. 213-220 ◽  
Author(s):  
C. Sissi ◽  
E. Vazquez ◽  
A. Chemello ◽  
L. A. Mitchenall ◽  
A. Maxwell ◽  
...  
Keyword(s):  
Dna Gyrase ◽  
Coumarin Derivative ◽  
Streptomyces Antibioticus ◽  
B Subunit ◽  
Terminal Domain ◽  
Antiproliferative Agent ◽  
Gyrase A ◽  
A Subunit ◽  
The Individual ◽  
Simocyclinone D8

ABSTRACT Simocyclinone D8, a coumarin derivative isolated from Streptomyces antibioticus Tü 6040, represents an interesting new antiproliferative agent. It was originally suggested that this drug recognizes the GyrA subunit and interferes with the gyrase catalytic cycle by preventing its binding to DNA. To further characterize the mode of action of this antibiotic, we investigated its binding to the reconstituted DNA gyrase (A2B2) as well as to its GyrA and GyrB subunits and the individual domains of these proteins, by performing protein melting and proteolytic digestion studies as well as inhibition assays. Two binding sites were identified, one (anticipated) in the N-terminal domain of GyrA (GyrA59) and the other (unexpected) at the C-terminal domain of GyrB (GyrB47). Stabilization of the A subunit appears to be considerably more effective than stabilization of the B subunit. Our data suggest that these two distinct sites could cooperate in the reconstituted enzyme.

scholarly journals The B Subunit of an AB5 Toxin Produced by Salmonella enterica Serovar Typhi Up-Regulates Chemokines, Cytokines, and Adhesion Molecules in Human Macrophage, Colonic Epithelial, and Brain Microvascular Endothelial Cell Lines

2012 ◽  
Vol 81 (3) ◽  
pp. 673-683 ◽  
Author(s):  
Hui Wang ◽  
James C. Paton ◽  
Brock P. Herdman ◽  
Trisha J. Rogers ◽  
Travis Beddoe ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Adhesion Molecule ◽  
Salmonella Enterica ◽  
Microvascular Endothelial Cell ◽  
Human Macrophage ◽  
U937 Cells ◽  
Brain Microvascular Endothelial Cell ◽  
Content Type ◽  
B Subunit ◽  
A Subunit

ABSTRACTThe principal function of bacterial AB5 toxin B subunits is to interact with glycan receptors on the surfaces of target cells and mediate the internalization of holotoxin. However, B subunit-receptor interactions also have the potential to impact cell signaling pathways and, in so doing, contribute to pathogenesis independently of the catalytic (toxic) A subunits. VariousSalmonella entericaserovars, includingSalmonella entericaserovar Typhi, encode an AB5 toxin (ArtAB), the A subunit of which is an ADP-ribosyltransferase related to the S1 subunit of pertussis toxin. However, although the A subunit is able to catalyze ADP-ribosylation of host G proteins, a cytotoxic phenotype has yet to be identified for the holotoxin. We therefore examined the capacity of the purified B subunit (ArtB) fromS. Typhi to elicit cytokine, chemokine, and adhesion molecule responses in human macrophage (U937), colonic epithelial (HCT-8) cell, and brain microvascular endothelial cell (HBMEC) lines. Secretion of the chemokines monocyte chemotactic protein 1 (MCP-1) and interleukin 8 (IL-8) was increased in all three tested cell lines, with macrophage inflammatory protein 1α (MIP-1α), MIP-1β, and granulocyte colony-stimulating factor (G-CSF) also significantly increased in U937 cells. ArtB also upregulated the cytokines tumor necrosis factor alpha (TNF-α) and IL-6 in HBMECs and HCT-8 cells, but not in U937 cells, while intercellular adhesion molecule 1 (ICAM-1) was upregulated in HCT-8 and U937 cells and vascular cell adhesion molecule 1 (VCAM-1) was upregulated in HBMECs. Thus, ArtB may contribute to pathogenesis independently of the A subunit by promoting and maintaining a strong inflammatory response at the site of infection.

scholarly journals Vacuolation Activity and Intracellular Trafficking of ArtB, the Binding Subunit of an AB5 Toxin Produced by Salmonella enterica Serovar Typhi

2017 ◽  
Vol 85 (8) ◽  
Author(s):  
Brock P. Herdman ◽  
James C. Paton ◽  
Hui Wang ◽  
Travis Beddoe ◽  
Adrienne W. Paton
Keyword(s):  
Cell Lines ◽  
Salmonella Enterica ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Target Cells ◽  
African Green Monkey Kidney ◽  
Content Type ◽  
B Subunit ◽  
Early Endosomes ◽  
A Subunit

ABSTRACT Various Salmonella enterica serovars, including S. enterica serovar Typhi, encode an AB5 toxin (ArtAB), the A subunit of which is an ADP-ribosyltransferase related to the S1 subunit of pertussis toxin. However, although the A subunit is able to catalyze ADP-ribosylation of host G proteins, a cytotoxic phenotype has yet to be identified for the holotoxin. Here we show that its B subunit pentamer (ArtB) binds to receptors on the surface of Vero (African green monkey kidney) cell, CHO (Chinese hamster ovary) cell, U937 (human monocyte) cell, and HBMEC (human brain microvascular endothelial cell) lines. Moreover, ArtB induced marked vacuolation in all cell lines after 4 h of incubation. Further studies in Vero cells showed that vacuolation was inhibited by bafilomycin A1 and was dependent on the clathrin-mediated uptake of ArtB. Vacuolation was also inhibited by treatment of cells with neuraminidase, indicating that sialylated glycans are functional receptors for ArtB. Confocal colocalization studies indicated that after cell binding and internalization, ArtB undergoes retrograde transport via early endosomes, the trans-Golgi network, and the Golgi apparatus, reaching the endoplasmic reticulum (ER) after approximately 2 h. The onset of vacuolation also coincided with gross cytoskeletal reorganization. At later time points, ArtB colocalized with ER-Tracker Red in the vacuolar membrane, implying that vacuolation is a consequence of ER disorganization. Thus, the isolated B subunit of this cryptic AB5 toxin has significant effects on target cells with the potential to contribute directly to pathogenesis independently of the catalytic A subunit.

scholarly journals OmpC Is the Receptor for Gifsy-1 and Gifsy-2 Bacteriophages of Salmonella

2001 ◽  
Vol 183 (4) ◽  
pp. 1495-1498 ◽  
Author(s):  
Theresa D. Ho ◽  
James M. Slauch
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Serovar Typhimurium ◽  
Selection For

ABSTRACT Mutations in the Salmonella enterica serovar Typhimurium ompC gene conferred resistance to Gifsy-1 and Gifsy-2 bacteriophages. Selection for complementing plasmids yielded clones of ompC. Introduction of anompC clone into Escherichia coliconferred the ability to adsorb Gifsy phage. These data show that OmpC is the receptor for Gifsy-1 and Gifsy-2 phages.

scholarly journals Increasing Prevalence of Quinolone Resistance in Human Nontyphoid Salmonella enterica Isolates Obtained in Spain from 1981 to 2003

2004 ◽  
Vol 48 (10) ◽  
pp. 3789-3793 ◽  
Author(s):  
José M. Marimón ◽  
María Gomáriz ◽  
Carmen Zigorraga ◽  
Gustavo Cilla ◽  
Emilio Pérez-Trallero
Keyword(s):  
Nalidixic Acid ◽  
Point Mutation ◽  
Salmonella Enterica ◽  
Single Point ◽  
Point Mutations ◽  
Fluoroquinolone Resistance ◽  
Human Consumption ◽  
Single Point Mutation ◽  
Gene Coding ◽  
Serovar Typhimurium

ABSTRACT From January 1981 to December 2003, susceptibility to nalidixic acid was tested in 10,504 nontyphoid Salmonella enterica isolates from patients with acute enteric disease in Gipuzkoa, Spain. The prevalence of nalidixic acid resistance steadily increased from less than 0.5% before 1991 to 38.5% in 2003, mainly due to the increase in resistance among isolates of the most prevalent serovar, S. enterica serovar Enteritidis. For nalidixic acid-resistant isolates, the ciprofloxacin MIC was eightfold higher than that for susceptible isolates, and the nalidixic acid-resistant isolates contained a single point mutation in the gyrA gene (at codons for Ser83 or Asp87). The same mutations were found in a sample of nalidixic acid-resistant nontyphoid Salmonella strains isolated between 1999 and 2003 from retail food for human consumption. In 2003, we identified five S. enterica serovar Typhimurium clinical isolates with high-level fluoroquinolone resistance (ciprofloxacin MIC, 16 μg/ml) with two point mutations in the gyrA gene (coding for Ser83→Phe and Asp87→Asn) and one point mutation in the parC gene (coding for Ser80→Arg). Strict sanitary controls are needed to avoid the spread of ciprofloxacin-resistant serovar Typhimurium isolates, and a more efficient veterinary policy must be adopted to decrease the large burden of Salmonella serovar Enteritidis infections in humans in our region.

ANTIMICROBIAL SUSCEPTIBILITY IN CULTURE POSITIVE ENTERIC FEVER

2019 ◽  
Vol 3 (7) ◽  
Author(s):  
Dr. Manish Kulshrestha ◽  
Dr. Anjali Kulshrestha
Keyword(s):  
Bone Marrow ◽  
Blood Culture ◽  
Nalidixic Acid ◽  
Antimicrobial Susceptibility ◽  
Salmonella Enterica ◽  
Enteric Fever ◽  
Multidrug Resistant ◽  
Bone Marrow Culture ◽  
Diffusion Method ◽  
Culture Positive

INTRODUCTION: Enteric fever includes typhoid and paratyphoid fever. Peak incidence is seen in children 5–15 years of age; but in regions where the disease is highly endemic, as in India, children younger than 5 years of age may have the highest infection rates. There are about 22 million new typhoid cases occur each year. Young children in poor, resource limited areas, who make up the majority of the new cases and there is a mortality figures of 215,000 deaths annually. A sharp decline in the rates of complications and mortality due to typhoid fever is observed as a result of introduction of effective antibiotic therapy since 1950s. MDR-ST became endemic in many areas of Asia, including India soon after multidrug-resistant strains of Salmonella enterica serotype typhi (MDR-ST) that were resistant to all the three first-line drugs then in use, namely chloramphenicol, amoxycillin and co-trimoxazole emerged in early 1990s. MATERIAL AND METHODS: Only blood culture or bone marrow culture positive cases were included. The patients with culture isolated enteric fever were included in the study. Antimicrobial susceptibility testing was carried out by disk diffusion method using antibiotic discs. The analysis of the antimicrobial susceptibility was carried out as per CLSI interpretative guidelines. RESULTS: A total of 82 culture positive cases were included in the present study. 80 culture isolates were from blood culture and 2 from the bone marrow culture. Salmonella entericasubspecies enterica serovartyphi (S typhi) was isolated from 67 (81.70%) patients while Salmonella enterica subspecies entericaserovarparatyphi (S paratyphi A) was isolated from 13 (15.85%) cases and 2 (2.44%) were Salmonella enterica subspecies entericaserovarschottmuelleri (S paratyphi B). Of the 82 cases 65(79.3%) isolates were resistant to ciprofloxacin, 17 (20.7%) were resistant to nalidixic acid, one (1.2%) case each was resistant to Cefotaxime and ceftriaxone, 2 (2.4%) were resistant to chloramphenicol, 10 (12.2%) were resistant and to cotrimoxazole 3 (3.7%) were resistant. CONCLUSION: In a culture positive cases 65(79.3%) isolates were resistant to ciprofloxacin and 17 (20.7%) were resistant to nalidixic acid. Multidrug resistant isolates were 65(79.3%).

Sign in / Sign up

Export Citation Format

Share Document