PURPOSE: In the gastric mucosa of Helicobacter pylori (H. pylori)-infected patients with gastritis or adenocarcinoma, proliferation of gastric epithelial cells is increased. Hyperproliferation is related to induction of oncogenes, such as β-catenin and c-myc. Even though transcription factors NF-κB and AP-1 are activated in H. pylori-infected cells, whether NF-κB or AP-1 regulates the expression of β-catenein or c-myc in H. pylori-infected cells has not been clarified. The present study was undertaken to investigate whether H. pylori-induced activation of NF-κB and AP-1 mediates the expression of oncogenes and hyperproliferation of gastric epithelial cells. MATERIALS AND METHODS: Gastric epithelial AGS cells were transiently transfected with mutant genes for IκBα (MAD3) and c-Jun (TAM67) or treated with a specific NF-κB inhibitor caffeic acid phenethyl ester (CAPE) or a selective AP-1 inhibitor SR-11302 to suppress activation of NF-κB or AP-1, respecively. As reference cells, the control vector pcDNA was transfected to the cells. Wild-type cells or transfected cells were cultured with or without H. pylori. RESULTS: H. pylori induced activation of NF-κB and AP-1, cell proliferation, and expression of oncogenes (β-catenein, c-myc) in AGS cells, which was inhibited by transfection of MAD3 and TAM67. Wild-type cells and the cells transfected with pcDNA showed similar activities of NF-κB and AP-1, proliferation, and oncogene expression regardless of treatment with H. pylori. Both CAPE and SR-11302 inhibited cell proliferation and expression of oncogenes in H. pylori-infected cells. CONCLUSION: H. pylori-induced activation of NF-κB and AP-1 regulates transcription of oncogenes and mediates hyperproliferation in gastric epithelial cells.
Blotting, Western ; Caffeic Acids ; Cell Line, Tumor ; Cell Proliferation ; DNA, Bacterial/analysis/genetics ; DNA-Binding Proteins/*metabolism ; Epithelial Cells/*metabolism ; Gastric Mucosa/*metabolism/pathology ; Gastritis/pathology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/metabolism/pathology/physiopathology ; Helicobacter pylori/pathogenicity/physiology ; Humans ; NF-kappa B/antagonists & inhibitors/*biosynthesis/metabolism ; Peptide Fragments ; Phenylethyl Alcohol/analogs & derivatives ; Proto-Oncogene Proteins c-jun ; Repressor Proteins ; Transcription Factor AP-1/*biosynthesis ; Transcription Factors/*metabolism ; beta Catenin/*metabolism

BACKGROUND: We evaluated the combined use of the modified Hodge test (MHT) and carbapenemase inhibition test (CIT) using phenylboronic acid (PBA) and EDTA to detect carbapenemase-producing Enterobacteriaceae (CPE) and metallo-beta-lactamase (MBL)-producing Pseudomonas spp. METHODS: A total of 49 isolates of CPE (15 Klebsiella pneumoniae carbapenemase [KPC], 5 Guiana extended-spectrum beta-lactamase [GES]-5, 9 New Delhi metallo-beta-lactamase [NDM]-1, 5 Verona integron-encoded metallo-beta-lactamase [VIM]-2, 3 imipenem-hydrolyzing beta-lactamase [IMP], and 12 oxacillinase [OXA]-48-like), 25 isolates of MBL-producing Pseudomonas spp. (14 VIM-2 and 11 IMP), and 35 carbapenemase-negative controls were included. The MHT was performed for all isolates as recommended by the Clinical and Laboratory Standards Institute. Enhanced growth of the indicator strain was measured in mm with a ruler. The CIT was performed by directly dripping PBA and EDTA solutions onto carbapenem disks that were placed on Mueller-Hinton agar plates seeded with the test strain. RESULTS: Considering the results of the MHT with the ertapenem disk in Enterobacteriaceae and Pseudomonas spp., the CIT with the meropenem disk in Enterobacteriaceae, and the imipenem disk in Pseudomonas spp., three combined disk tests, namely MHT-positive plus PBA-positive, EDTA-positive, and MHT-positive plus PBA-negative plus EDTA-negative, had excellent sensitivity and specificity for the detection of KPC- (100% sensitivity and 100% specificity), MBL- (94% sensitivity and 100% specificity), and OXA-48-like-producing isolates (100% sensitivity and 100% specificity), respectively. CONCLUSIONS: Combined use of the MHT and CIT with PBA and EDTA, for the detection of CPE and MBL-producing Pseudomonas spp., is effective in detecting and characterizing carbapenemases in routine laboratories.
Bacterial Proteins/antagonists & inhibitors/*metabolism ; Boronic Acids/chemistry/pharmacology ; Disk Diffusion Antimicrobial Tests/*methods ; Edetic Acid/chemistry/pharmacology ; Enterobacteriaceae/drug effects/*enzymology ; Enterobacteriaceae Infections/diagnosis ; Humans ; Pseudomonas/drug effects/*enzymology ; Pseudomonas Infections/diagnosis ; Sensitivity and Specificity ; beta-Lactamases/chemistry/*metabolism

Dehydration is one of the key steps in the biosynthesis of mycolic acids and is vital to the growth of Mycobacterium tuberculosis (Mtb). Consequently, stalling dehydration cures tuberculosis (TB). Clinically used anti-TB drugs like thiacetazone (TAC) and isoxyl (ISO) as well as flavonoids inhibit the enzyme activity of the β-hydroxyacyl-ACP dehydratase HadAB complex. How this inhibition is exerted, has remained an enigma for years. Here, we describe the first crystal structures of the MtbHadAB complex bound with flavonoid inhibitor butein, 2',4,4'-trihydroxychalcone or fisetin. Despite sharing no sequence identity from Blast, HadA and HadB adopt a very similar hotdog fold. HadA forms a tight dimer with HadB in which the proteins are sitting side-by-side, but are oriented anti-parallel. While HadB contributes the catalytically critical His-Asp dyad, HadA binds the fatty acid substrate in a long channel. The atypical double hotdog fold with a single active site formed by MtbHadAB gives rise to a long, narrow cavity that vertically traverses the fatty acid binding channel. At the base of this cavity lies Cys61, which upon mutation to Ser confers drug-resistance in TB patients. We show that inhibitors bind in this cavity and protrude into the substrate binding channel. Thus, inhibitors of MtbHadAB exert their effect by occluding substrate from the active site. The unveiling of this mechanism of inhibition paves the way for accelerating development of next generation of anti-TB drugs.
Amino Acid Sequence ; Bacterial Proteins ; chemistry ; metabolism ; Catalytic Domain ; Enzyme Inhibitors ; chemistry ; pharmacology ; Flavonoids ; chemistry ; pharmacology ; Hydro-Lyases ; antagonists & inhibitors ; chemistry ; Molecular Sequence Data ; Mycobacterium tuberculosis ; drug effects ; enzymology ; Protein Binding ; drug effects ; Protein Multimerization ; drug effects ; Protein Structure, Secondary ; Sequence Alignment

BACKGROUND: Acinetobacter baumannii is one of the most important pathogens capable of colonization in burn patients, leading to drug-resistant wound infections. This study evaluated the distribution of the AdeABC efflux system genes and their relationship to ciprofloxacin resistance in A. baumannii isolates collected from burn patients. METHODS: A total of 68 A. baumannii clinical strains were isolated from patients hospitalized in Motahari Burns Center in Tehran, Iran. Ciprofloxacin susceptibility was tested by the disk diffusion and agar dilution methods. PCR amplification of the adeRS-adeB drug efflux genes was performed for all resistant and susceptible isolates. To assess the role of the drug efflux pump in ciprofloxacin susceptibility, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) was used as an efflux pump inhibitor (EPI). RESULTS: Approximately 95.6% of the Acinetobacter isolates were resistant to ciprofloxacin, with minimum inhibitory concentration (MIC) values ranging from 4 to > or =128 microg/mL. The susceptibility of 86.1% of the resistant isolates increased by factors of 2 to 64 in the presence of CCCP. All resistant isolates were positive for the adeRS-adeB genes, and 73.2% of them had mutations in the AdeRS regulatory system. CONCLUSIONS: The results showed that AdeABC genes are common in A. baumannii, which might be associated with ciprofloxacin non-susceptibility, as indicated by the observed linkage to the presence of the genes essential for the activity of the AdeABC, several single mutations occurring in the adeRS regulatory system, and an increase of ciprofloxacin susceptibility in the presence of a CCCP EPI.
ATP-Binding Cassette Transporters/antagonists & inhibitors/genetics/*metabolism ; Acinetobacter Infections/diagnosis/microbiology ; Acinetobacter baumannii/*drug effects/genetics/isolation & purification ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/antagonists & inhibitors/genetics/*metabolism ; Base Sequence ; Ciprofloxacin/*pharmacology ; DNA, Bacterial/chemistry/genetics/metabolism ; Drug Resistance, Bacterial ; Humans ; Hydrazones/pharmacology ; Microbial Sensitivity Tests ; Mutation ; Polymerase Chain Reaction

New antibiotics with novel modes of action and structures are urgently needed to combat the emergence of multidrug-resistant bacteria. Bacterial signal peptidase I (SPase I) is an indispensable enzyme responsible for cleaving the signal peptide of preprotein to release the matured proteins. Increasing evidence suggests that SPase I plays a crucial role in bacterial pathogenesis by regulating the excretion of a variety of virulent factors, maturation of quorum sensing factor and the intrinsic resistance against beta-lactams. Recently, breakthrough has been achieved in the understanding of three-dimensional structure of SPase I as well as the mechanism of enzyme-inhibitors interaction. Three families of inhibitors are identified, i.e. signal peptide derivatives, beta-lactams and arylomycins. In this article, we summarize the recent advance in the study of structure, activity and structure-activity relationship of SPase I inhibitors.
Animals ; Anti-Bacterial Agents ; pharmacology ; Bacteria ; drug effects ; Escherichia coli ; drug effects ; Membrane Proteins ; antagonists & inhibitors ; metabolism ; Oligopeptides ; chemistry ; pharmacology ; Serine Endopeptidases ; metabolism ; Serine Proteinase Inhibitors ; chemistry ; pharmacology ; Structure-Activity Relationship ; beta-Lactams ; antagonists & inhibitors

Carbapenem-resistant Klebsiella pneumoniae isolates producing K. pneumoniae carbapenemases (KPC) were first reported in the USA in 2001, and since then, this infection has been reported in Europe, Israel, South America, and China. In Korea, the first KPC-2-producing K. pneumoniae sequence type (ST) 11 strain was detected in 2010. We report the case of a patient with a urinary tract infection caused by KPC-2-producing K. pneumoniae. This is the second report of a KPC-2-producing K. pneumoniae infection in Korea, but the multilocus sequence type was ST258. The KPC-2-producing isolate was resistant to all tested beta-lactams (including imipenem and meropenem), amikacin, tobramycin, ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole, but was susceptible to gentamicin, colistin, polymyxin B, and tigecycline. The KPC-2-producing isolate was negative to phenotypic extended-spectrum beta-lactamase (ESBL) and AmpC detection tests and positive to modified Hodge test and carbapenemase inhibition test with aminophenylboronic acid.
Aged ; Bacterial Proteins/antagonists & inhibitors/metabolism ; Carbapenems/pharmacology ; Drug Resistance, Bacterial/genetics ; Female ; Humans ; Klebsiella pneumoniae/drug effects/genetics/*isolation & purification ; Microbial Sensitivity Tests ; Republic of Korea ; Sequence Analysis, DNA ; Urinary Tract Infections/*diagnosis/microbiology ; beta-Lactamases/antagonists & inhibitors/biosynthesis/*genetics/metabolism

Bacterial biofilms can be viewed as a specific type of persistent bacterial infection. After initial invasion, microbes can attach to living and non-living surfaces, such as prosthetics and indwelling medical devices, and form a biofilm composed of extracellular polysaccharides, proteins, and other components. In hosts, biofilm formation may trigger drug resistance and inflammation, resulting in persistent infections. The clinical aspects of biofilm formation and leading strategies for biofilm inhibitors will be discussed in this mini-review.
Adhesins, Bacterial ; drug effects ; physiology ; Aminoacyltransferases ; antagonists & inhibitors ; genetics ; Animals ; Antimicrobial Cationic Peptides ; genetics ; pharmacology ; Bacterial Infections ; microbiology ; surgery ; Bacterial Proteins ; antagonists & inhibitors ; genetics ; Biofilms ; drug effects ; growth & development ; Chronic Disease ; Cysteine Endopeptidases ; genetics ; Cysteine Proteinase Inhibitors ; pharmacology ; Humans ; Inflammation ; microbiology ; Quorum Sensing ; drug effects ; physiology ; Wound Infection ; microbiology ; surgery

Reversible protein phosphorylation regulates multiple biochemical events. Mycobacterium tuberculosis phosphatases play important roles in regulating the pathogen physiology and interference of host signaling. They are also involved in the evasion of host immune response and blockage of the phagosome-lysosome fusion. Selective inhibition of phosphatase represents an ideal new avenue of anti-tuberculosis drug design. In this paper, we update the progresses about the regulation network of Mycobacterium tuberculosis phosphatases including MptpA, MptpB, MstP, SapM and their inhibitors. These serve as the basis for further antituberculosis drug target.
Acid Phosphatase ; antagonists & inhibitors ; metabolism ; Animals ; Antitubercular Agents ; pharmacology ; Bacterial Proteins ; antagonists & inhibitors ; metabolism ; Humans ; Mycobacterium tuberculosis ; drug effects ; enzymology ; Protein Tyrosine Phosphatases ; antagonists & inhibitors ; metabolism

OBJECTIVETo study the active compounds from the rhizomes of Musa basjoo.

METHODAntioxidant and alpha-glucosidase inhibitory activity of different extracts were tested. Using bioassay-guided fractionation, the chemical constituents in EtOAC extracts were isolated by column chromatography and identified by MS and NMR spectroscopy.

RESULTFive compounds were isolated and identified as 2',3, 4'-trihydroxyflavone (1), 3,3'-bis-hydroxyanigorufone (2), irenolone (3), 4-dihydroxy-9-(4'-hydroxyphenyl)-phenalenone (4) and 3,4-dihydroxybenzaldehyde (5). Compound 1(IC50 8.61 mg x L(-1)), 3 (IC50 19.55 mg x L(-1)) and 5 (IC50 1.1 mg x L(-1)) had antioxidant activity. Compound 2 (IC50 24.15 mg x L(-1)) and 4(IC50 2.81 mg x L(-1)) had alpha-glucosidase inhibitory activity. Compound 5 showed MIC of 0.078, 0.313, 0.039 microg/disc against SA, MRSA and ESBLs, respectively.

CONCLUSIONCompound 1-5 were isolated from this plant for the first time. Compound 5 was isolated from the genus Musa for the first time. All compound except 5 were first reported about activity.

Bacterial Proteins ; analysis ; antagonists & inhibitors ; Enzyme Inhibitors ; analysis ; isolation & purification ; pharmacology ; Glycoside Hydrolase Inhibitors ; Musa ; chemistry ; Plant Extracts ; analysis ; isolation & purification ; pharmacology ; Rhizome ; chemistry ; Staphylococcus aureus ; drug effects ; enzymology ; alpha-Glucosidases ; analysis

BACKGROUND/AIMS: Ligands for peroxisome proliferator-activated receptor gamma (PPAR gamma), a member of the ligand-activated nuclear receptor superfamily, exhibit anti-tumoral effects and are associated with de novo synthesis of proteins involved in regulating the cell cycle and cell survival/death. Helicobacter pylori (H. pylori) is an etiologic agent for gastric adenocarcinoma, and raises the cell turnover of gastric epithelium. The aim of this study was to investigate the effect of PPAR gamma ligand rosiglitazone on the cell proliferation and the expressions of p27 and Skp2 protein in H. pylori infected gastric epithelial cells. METHODS: We examined the expression of PPAR gamma by Western blot in H. pylori infected AGS human gastric epithelial cells. The effect of rosiglitazone on the survival of H. pylori infected AGS cells was assessed by cell viability assay. After the treatment of rosiglitazone in H. pylori infected AGS cells, the expressions of p27 and Skp2 were assessed by Western blot. RESULTS: The expression of PPAR gamma protein was increased in H. pylori infected AGS cells. Cell growth was inhibited and decreased in dose- and time- dependent manner in H. pylori infected AGS cells treated with rosiglitazone. A decrease in Skp2 expression and a reciprocal increase in p27 expression were found in dose- and time-dependent manner in H. pylori infected AGS cells treated with rosiglitazone. CONCLUSIONS: Rosiglitazone inhibited the growth of H. pylori infected AGS cells. Rosiglitazone attenuated Skp2 expression, thereby promoting p27 accumulation in H. pylori infected human gastric epithelial cells. Further studies will be needed to find the effects of accumulation on cell turnover in H. pylori infection and the role in the H. pylori-associated gastric carcinogenesis.
Anti-Bacterial Agents/*pharmacology ; Cell Line ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p27/*metabolism ; Epithelial Cells/metabolism/*microbiology ; Gastric Mucosa/cytology/metabolism/*microbiology ; *Helicobacter pylori ; Humans ; PPAR gamma/antagonists &inhibitors/metabolism ; S-Phase Kinase-Associated Proteins/*metabolism ; Thiazolidinediones/*pharmacology