Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017160 (gastroenteritis)
 11,398 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Campylobacter jejuni, a gram-negative organism causing gastroenteritis in humans, is increasingly resistant to antibiotics. However, little is known about the drug efflux mechanisms in this pathogen. Here we characterized an efflux pump encoded by a three-gene operon (designated cmeABC) that contributes to multidrug resistance in C. jejuni 81-176. CmeABC shares significant sequence and structural homology with known tripartite multidrug efflux pumps in other gram-negative bacteria, and it consists of a periplasmic fusion protein (CmeA), an inner membrane efflux transporter belonging to the resistance-nodulation-cell division superfamily (CmeB), and an outer membrane protein (CmeC). Immunoblotting using CmeABC-specific antibodies demonstrated that cmeABC was expressed in wild-type 81-176; however, an isogenic mutant (9B6) with a transposon insertion in the cmeB gene showed impaired production of CmeB and CmeC. Compared to wild-type 81-176, 9B6 showed a 2- to 4,000-fold decrease in resistance to a range of antibiotics, heavy metals, bile salts, and other antimicrobial agents. Accumulation assays demonstrated that significantly more ethidium bromide and ciprofloxacin accumulated in mutant 9B6 than in wild-type 81-176. Addition of carbonyl cyanide m-chlorophenylhydrazone, an efflux pump inhibitor, increased the accumulation of ciprofloxacin in wild-type 81-176 to the level of mutant 9B6. PCR and immunoblotting analysis also showed that cmeABC was broadly distributed in various C. jejuni isolates and constitutively expressed in wild-type strains. Together, these findings formally establish that CmeABC functions as a tripartite multidrug efflux pump that contributes to the intrinsic resistance of C. jejuni to a broad range of structurally unrelated antimicrobial agents.
 ...
PMID:CmeABC functions as a multidrug efflux system in Campylobacter jejuni. 1206 64

A protocol for obtaining small amounts of highly pure virus preparations starting from reduced volumes (<5 ml) of infected tissue culture supernatants is described. This procedure was adapted to the study of transmissible gastroenteritis coronavirus (TGEV) protein composition and RNA encapsidation. This protocol relies on virion capture by monoclonal antibodies specific for a virion membrane protein. These antibodies were bound to protein A-coated ELISA wells armed with rabbit anti-mouse IgG antibodies. As an example, the purification of (35)S-labelled TGEV virions was performed. The quality of virus preparations was assessed by quantifying common contaminating RNAs by real-time RT-PCR. The most critical factors influencing the purity degree are analysed and discussed.
 ...
PMID:Immunopurification applied to the study of virus protein composition and encapsidation. 1515 85

Monoclonal antibodies to porcine epidemic diarrhoea virus (PEDV) membrane protein M were prepared and used for the comparative assessment of three blocking ELISA variants to detect PEDV. The competitive blocking ELISA (CB-ELISA) format showed the highest sensitivity, allowing detection of 10(2.5) plaque-forming units of PEDV/ml in culture medium. Its specificity was verified by inclusion of control samples containing transmissible gastroenteritis virus (TGEV) and rotavirus A in each analysis. Eighty porcine field samples of faeces obtained from 38 herds affected with diarrhoea were examined, and PEDV was found in 15 (19%) samples from 6 (16%) herds. The suitability of the CB-ELISA for the screening herds in epizootiologic situations is discussed.
 ...
PMID:An ELISA optimized for porcine epidemic diarrhoea virus detection in faeces. 1560 79

In pathogenic bacteria, iron acquisition is important for colonization and proliferation in the host under iron-limited conditions. The ability of Vibrio spp. to acquire iron is often critical to their virulence, causing gastroenteritis or excessive watery diarrhea in humans. In the study described here, we cloned the 2,100-bp heme utilization protein gene hupO in Vibrio fluvialis. HupO had high homology to iron-regulated outer membrane receptor proteins in Vibrio sp. and contained motifs that are common to bacterial heme receptors, including a consensus TonB box, a FRAP domain, and an NPNL domain. To characterize the hemin-binding activity of HupO, we purified the recombinant HupO protein (rHupO) from Escherichia coli by using an overexpression system. HupO was found to bind to hemin but not to hemoglobin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting demonstrated that the 77-kDa outer membrane protein HupO of V. fluvialis was induced under iron-restricted conditions. We constructed a hupO mutant, HP1, to investigate the biochemical function of HupO in V. fluvialis. The hemolytic activity of HP1 was reduced compared to that of wild-type cells and, when exposed to hydrogen peroxide, significantly lower numbers of HP1 survived than was the case in the wild type. These results suggest that HupO is associated with virulence expression in V. fluvialis through stimulation of hemolysin production and resistance to oxidative stress. In experimentally infected mice, the 50% lethal dose value of the wild-type was lower than that of the mutant, HP1.
 ...
PMID:Identification of an iron-regulated hemin-binding outer membrane protein, HupO, in Vibrio fluvialis: effects on hemolytic activity and the oxidative stress response. 1566 10

Monoclonal antibodies (mAb) to the transmissible gastroenteritis virus (TGEV) nucleoprotein (N) and membrane protein (M) were prepared and used for the comparative assessment of three blocking ELISA variants to detect TGEV. The competitive blocking ELISA format showed the highest sensitivity, allowing detection of 10(3) TCID50 TGEV/ml in culture medium. Ninety-nine porcine field faecal samples obtained from 37 herds affected with diarrhoea were examined, and various TGEV levels were found in nine samples from six herds. However, only in three samples were significant TGEV concentrations demonstrated. The relationship between incidence of TGEV gastroenteritis and the spread of porcine respiratory coronavirus infection in pig farms is discussed.
 ...
PMID:Use of monoclonal antibodies in blocking ELISA detection of transmissible gastroenteritis virus in faeces of piglets. 1587 21

Salmonella enterica serovar typhimurium (S. typhimurium) is an intracellular pathogen causing localized gastroenteritis in humans. Macrophages (Mphis) and dendritic cells (DCs) play an important role in innate immunity against Salmonella. In this report, we have compared the consequences of infection of human Mphis and DCs with wild-type S. typhimurium and an isogenic PgtE-defective strain. PgtE is an outer membrane protein hypothesized to have a role in intracellular survival of Salmonella. We observed that DCs undergo full maturation in response to Salmonella infection, as indicated by up-regulation of cell-surface marker proteins CD80, CD83, CD86, and human leukocyte antigen class II. CC chemokine ligand 5 (CCL5), CXC chemokine ligand 10, tumor necrosis factor alpha, interleukin (IL)-12, and IL-18 gene expression and protein production were readily induced by Salmonella-infected Mphis and DCs. CCL20 was preferentially produced by Mphis, whereas DCs secreted higher levels of CCL19 as compared with Mphis. DCs and Mphis infected with S. typhimurium also produced high levels of interferon-gamma (IFN-gamma). Cytokine neutralization and stimulation experiments suggest that the production was partly regulated by Salmonella-induced type I IFNs, IL-12, and IL-18. DC cytokine production induced by Salmonella was much higher as compared with the responses induced by Salmonella lipopolysaccharide or flagellin. Mphis and DCs were capable of internalizing and harboring Salmonella for several days. S. enterica PgtE provided no survival advantage for the bacteria in human Mphis or DCs. Our results demonstrate that although Mphis and DCs share similar functions, they may have different roles during Salmonella infection as a result of differential production of certain chemokines and cytokines.
 ...
PMID:Activation, cytokine production, and intracellular survival of bacteria in Salmonella-infected human monocyte-derived macrophages and dendritic cells. 1603 11

A novel coronavirus, designated as ferret enteric coronavirus (FECV), was identified in feces of domestic ferrets clinically diagnosed with epizootic catarrhal enteritis (ECE). Initially, partial sequences of the polymerase, spike, membrane protein, and nucleocapsid genes were generated using coronavirus consensus PCR assays. Subsequently, the complete sequences of the nucleocapsid gene and the last two open reading frames at the 3' terminus of the FECV genome were obtained. Phylogenetic analyses based on predicted partial amino acid sequences of the polymerase, spike, and membrane proteins, and full sequence of the nucleocapsid protein showed that FECV is genetically most closely related to group 1 coronaviruses. FECV is more similar to feline coronavirus, porcine transmissible gastroenteritis virus, and canine coronavirus than to porcine epidemic diarrhea virus and human coronavirus 229E. Molecular data presented in this study provide the first genetic evidence for a new coronavirus associated with clinical cases of ECE.
 ...
PMID:Molecular characterization of a novel coronavirus associated with epizootic catarrhal enteritis (ECE) in ferrets. 1649 43

Campylobacter is now recognized as the most common bacterial agent of gastroenteritis. The adhesion of bacteria to intestinal cells is a major step in human colonization. The binding of Campylobacter jejuni cells to fibronectin (Fn), a component of the extra cellular matrix, is mediated by a 37,000 outer membrane protein termed CadF for Campylobacter adhesion to Fn. CadF protein is very hard to purify from Campylobacter membranes. In order to study the conformation of this protein, we set out to clone, express, purify, and re-fold the CadF protein. The nucleotide sequence encoding the N-terminal domain of the CadF protein was cloned in a pET-based expression vector. The recombinant protein was further produced in Escherichia coli, purified from inclusion bodies, and refolded. More specifically, the purification experiments were set-up as follows: (i) protein aggregates were collected from cell-lysates, solubilized in urea and enriched by ion-exchange chromatography; (ii) refolding was achieved by drop-by-drop dilution method in detergent containing buffer and monitored by CD measurements; (iii) the protein was finally purified to homogeneity by gel filtration chromatography. In spite of our success in purifying the N-terminal domain of the CadF protein, repeated attempts to express and purify the entire cadF gene in E. coli failed. Using a novel approach, we found it possible to express the entire cadF gene fused to a hexa-histidine encoding nucleotide sequence in C. jejuni. This allowed the expression, synthesis, and purification of the recombinant CadF-His tagged protein from C. jejuni by nickel affinity chromatography followed by gel filtration chromatography. In summary, we developed a novel strategy to produce significant quantities of a recombinant N-terminal portion of the CadF protein (46.5 microg/mg of bacterial dry weight) and of the native CadF protein (3.5 microg/mg of bacterial dry weight) for further studies.
 ...
PMID:Expression and purification of native and truncated forms of CadF, an outer membrane protein of Campylobacter. 1662 Sep 52

The small envelope protein (E) plays a role of central importance in the assembly of coronaviruses. This was initially established by studies demonstrating that cellular expression of only E protein and the membrane protein (M) was necessary and sufficient for the generation and release of virus-like particles. To investigate the role of E protein in the whole virus, we previously generated E gene mutants of mouse hepatitis virus (MHV) that were defective in viral growth and produced aberrantly assembled virions. Surprisingly, however, we were also able to isolate a viable MHV mutant (DeltaE) in which the entire E gene, as well as the nonessential upstream genes 4 and 5a, were deleted. We have now constructed an E knockout mutant that confirms that the highly defective phenotype of the DeltaE mutant is due to loss of the E gene. Additionally, we have created substitution mutants in which the MHV E gene was replaced by heterologous E genes from viruses spanning all three groups of the coronavirus family. Group 2 and 3 E proteins were readily exchangeable for that of MHV. However, the E protein of a group 1 coronavirus, transmissible gastroenteritis virus, became functional in MHV only after acquisition of particular mutations. Our results show that proteins encompassing a remarkably diverse range of primary amino acid sequences can provide E protein function in MHV. These findings suggest that E protein facilitates viral assembly in a manner that does not require E protein to make sequence-specific contacts with M protein.
 ...
PMID:Exceptional flexibility in the sequence requirements for coronavirus small envelope protein function. 1718 90

Campylobacter jejuni and Campylobacter coli are the bacterial cause of human gastroenteritis commonly reported worldwide. The serodiagnosis of Campylobacter infections is not routinely done in Poland so the aim of this study was to evaluation of ELISA in the diagnosis ofcampylobacteriosis. Serum samples obtained from 145 patients with gastroenteritis were tested by ELISA with 7 different heat-stable antigens of C. jejuni and one of C. coli and by the commercial Virion/Serion ELISA with purified 45 kDa outer membrane protein of C. jejuni. Antibodies for heat-stable antigens of C. jejuni were detected statistically more often than antibodies for heat-stable antigens of C. coli and for purifled protein of C. jejuni. We found significant differences in the frequency of detection of antibodies to different heat-stable antigens, ranged from 18.6% to 68.9% of positive results, what indicate for serological heterogenicity of C. jejuni strains isolated in Poland. The results of our study showed usefulness of ELISA in serological diagnosis of campylobacteriosis. However it is necessary to serotype the C. jejuni strains isolated in Poland to find the appropriate C. jejuni serotype for using in ELISA.
 ...
PMID:[Enzyme-linked immunosorbent assay in the diagnosis of campylobacteriosis]. 1841 28


<< Previous 1 2 3 4 5 6 Next >>