In vitro inhibition of Helicobacter pylori urease with non and semi fermented Camellia sinensis

Purpose: Helicobacter pylori is the etiological agent in duodenal and peptic ulcers. The growing problem of antibiotic resistance by the organism demands the search for novel compounds, especially from natural sources. This study was conducted to evaluate the effect of Camellia sinensis extracts on the urease enzyme that is a major colonization factor for H. pylori. Methods: Minimum inhibitory concentrations of nonfermented and semifermented C. sinensis methanol: water extracts were assessed by broth dilution method. Examination of the urease function was performed by Mc Laren method, and urease production was detected on 12% SDS polyacrylamide gel electrophoresis from whole cell and membrane bound proteins. Results: Both extracts had inhibitory effects against H. pylori and urease production. At a concentration of 2.5 mg/ml of nonfermented extract and 3.5 mg/ml of semifermented extract the production of Ure A and Ure B subunits of the urease enzyme were inhibited completely. A concentration of 4 mg/ml of nonfermented and 5.5 mg/ml of semifermented extract were bactericidal for H. pylori. Conclusions: C. sinensis extracts, especially the nonfermented, could reduce H. pylori population and inhibit urease production at lower concentrations. The superior effect of nonfermented extract is due to its rich polyphenolic compounds and catechin contents

The effect of type II toxin-antitoxin systems on methicillinresistant Staphylococcus aureus persister cell formation and antibiotic tolerance

Persister cells are defi ned as a subpopulation of bacteria in a dormant state with the ability to reduce bacterial metabolism and they are involved in antibiotic tolerance. Toxin-antitoxin (TA) systems have been previously suggested as important players in persistence. Therefore, this study aimed to study the involvement of TA systems in persister cell formation in methicillin-resistant Staphylococcus aureus following antibiotic exposure. Using TADB and RASTA database, two type II TA systems including MazF/MazE and RelE/RelB were predicted in S. aureus. The presence of these TA genes was determined in 5 methicillin-resistant S. aureus isolates and the standard strain S. aureus subsp. aureus N315 using PCR method. To induce persistence, isolates were exposed to lethal doses of ciprofl oxacin and the expression of the studied TA system genes was measured after 5 h using Real-Time PCR. According to our results, all the studied isolates harbored the TA system genes. S. aureus was highly capable of persister cell formation following exposure to sub-MIC of ciprofl oxacin and RT-qPCR showed a signifi cant increase in the expression of the MazEF and RelBE loci, indicating their potential role in antibiotic tolerance. Considering the importance of antibiotic tolerance, further studies on persister cell formation and TA systems involved in this phenomenon are required to effi ciently target these systems

Virulence increasing of salmonella typhimurium in Balb/c Mice after heat-stress induction of phage shock protein A

View at Publisher| Export | Download | Add to List | More... Current Microbiology Volume 59, Issue 4, October 2009, Pages 446-450 Virulence increasing of salmonella typhimurium in Balb/c Mice after heat-stress induction of phage shock protein A (Article) Hassani, A.S.ab, Amirmozafari, N.c, Ghaemi, A.bd a Department of Microbiology, Fars Science and Research Branch of IAU, Shiraz, Fars, Iran b Young Researchers Club (YRC) of Science and Research Branch, Islamic Azad University, Tehran, Iran c Department of Microbiology, Iran University of Medical Sciences, Tehran, Iran View additional affiliations View references (39) Abstract Salmonella typhimurium is a potentially intracellular pathogen and is responsible for thousands of reported cases of acute gastroenteritis and diarrhea each year. Although many successful physiological and genetic approaches have been taken to conclude the key virulence determinants encoded by this organism, the total number of uncharacterized reading frames observed within the S. typhimurium genome suggests that many virulence factors remain to be discovered. This study was conducted to evaluate the role of heat induced phage shock protein A (PspA), in the pathogenicity of S. typhimurium. The stress proteins detected on sodium dodecyl sulfate-polyacrylamide gel electrophoresis were identified specifically by immunoblotting with polyclonal antibody against PspA. PspA was produced in response to heat stress at 45°C and it was over-expressed at 65°C. At this temperature, the stressed bacterial cells producing PspA were more virulent (16 folds greater) to female 6-8 week-old Balb/c mice. Correspondency between decrease in LD50 and increase in PspA production during heat stress and lower pathogenicity in non-producing cells that emerged during stress at 55°C represents PspA as an important virulence factor in heat stressed S. typhimurium. © 2009 Springer Science+Business Media, LLC

Purification and characterization of &#945-galactosidase from Lactobacillus acidofillus

α−Galactosidase (α-D-galactoside galactohydrolase [EC 3.2.1.22]) was obtained from Lactobacillus acidofillus which was grown in modified de Man, Rogosa and Sharpe (MRS) medium, supplemented with raffinose. α-Galactosidase was released from the cells by ultrasonic treatment, then precipitated by ammonium-sulfate and further purified with Sephadex G-200 and DEAE cellulose chromatography with a 18.5-fold increase in specific activity and 28% recovery. Km and Vmax for this enzyme was determined by p-nitrophenyl-α-D-galactoside as substrate, to be about 0.47 mM, and 17.54 μmol/min per mg of protein, respectively. Maximum enzymatic activity occurred at pH 5.5 and temperature at 45°C. The enzymatic activity was retained at least for 30 min, at temperatures of 25 - 55°C, but there was inactive temperature at about 60°C. Galactose was able to decrease the enzyme activity by a factor of 63%. Among the sugars tested, fructose, glucose, sucrose, lactose and mannose reduced the enzyme activity only slightly (less than 10% of the control). A strong inhibition of α-galactosidase activity was found in the presence of 0.1 mM HgCl.Key words: α-Galactosidase, enzyme purification, Lactobacillus acidofillus, kinetic studies

Prevalence of Chlamydia trachomatis infections in symptomatic women by polymerase chain reaction (PCR) immunofluorescence and Giemsa stain

Chlamydia trachomatis is a ubiquitous human pathogen that is responsible for the most prevalent bacterial sexually transmitted disease worldwide. Studies show that polymerase chain reaction (PCR) is more sensitive than cellular culture for detection of C. trachomatis infections. The aim of this study is to compare different laboratory methods, including Giemsa staining, direct immunofluorescence assay (DFA) and PCR for detection of C. trachomatis in women with urethral symptoms. In this study, 130 women with urethral symptoms admitted in the gynecology clinic, were used and specimens were obtained with endocervical swab for Giemsa staining, DFA and PCR. All the cases underwent these three techniques. Demographic data and the medical history of patients were obtained by direct interview; however, the mean age of cases was 33.8±9.06. Clinical symptoms included abnormal vaginal discharge in 101 cases (77.7%), spotting in 14 cases (10.8%), dysmenorrheal in 7 cases (5.4%), irritation in 6 cases (4.6%) and dysuria in 2 cases (1.5%). In DFA technique, 5 cases (3.8%) were positive and 3 (2.3%) were suspicious, while in the PCR technique, 6 cases (4.6%) were positive for C. trachomatis. However, 3 suspicious cases with DFA were negative in PCR. There was no positive case for C. trachomatis in Giemsa staining. In conclusion, C. trachomatis was not frequent in this study and it can be concluded that this infection was not a major hygienic problem in the same populations that were previously studied. Consequently, the causes that necessitate monogamy could be related to religious causes. Frequency of Chlamydia detection of DFA and PCR was same in the two groups. Nonetheless, Giemsa staining is not a reliable method for evaluating C. trachomatis.Key words: Chlamydia trachomatis, polymerase chain reaction (PCR), direct immunofluorescence assay (DFA)

Biofilm formation in clinical isolates of nosocomial Acinetobacter baumannii and its relationship with multidrug resistance

AbstractObjectiveTo check biofilm formation by Acinetobacter baumannii (A. baumannii) clinical isolates and show their susceptibility to different antibiotics and investigate a possible link between establishment of biofilm and multidrug resistance.MethodsThis study was performed on clinical samples collected from patients with nosocomial infections in three hospitals of Tehran. Samples were initially screened by culture and biochemical tests for the presence of different species of Acinetobacter. Identifications were further confirmed by PCR assays. Their susceptibilities to 11 antibiotics of different classes were determined by disc diffusion method according to Clinical and Laboratory Standards Institute guidelines. The ability to produce biofilm was investigated using methods: culture on Congo red agar, microtiter plate, and test tube method.ResultsFrom the overall clinical samples, 156 specimens were confirmed to contain A. baumannii. The bacteria were highly resistant to most antibiotics except polymyxin B. Of these isolates, 10.26% were able to produce biofilms as shown on Congo red agar. However, the percentage of bacteria with positive biofilm in test tube, standard microtiter plate, and modified microtiter plate assays were 48.72%, 66.66%, and 73.72%, respectively. At least 92% of the biofilm forming isolates were multidrug resistant.ConclusionsSince most of the multidrug resistant strains produce biofilm, it seems necessary to provide continuous monitoring and determination of antibiotic susceptibility of clinical A. baumannii. This would help to select the most appropriate antibiotic for treatment

Association between single nucleotide polymorphism of apoVLDL-II gene with growth and body composition traits in Iranian commercial broiler line

Very low density apolipoprotein-II (apoVLDL-II) is a major polypeptide component of avian VLDL. The function of apoVLDL-II is the transport of neutral lipids (triacylglycerol) in the form of VLDL in the plasma. The apoVLDLII gene is dormant in embryos, chicks and roosters but can be activated by estrogen. The current study was designed to investigate the association of an apoVLDL-II gene polymorphism on chicken growth and body composition traits. Genomic DNAs were extracted from 400chickens from four different commercial broiler lines. Genotyping for the apoVLDL-II gene by using PCR-RFLP method and SfcI restriction endonuclease showed a mutation in 492-bp fragment located on the first intron. Polymorphism in apoVLDL-II gene was significantly (P < 0.05) associated with body weight at 6 week (BW6), carcass weight (CW), breast muscle weight (BMW), drumstick weight (DW) and wing weight (WINW). No significant difference was observed in the back weight (BAKW) and abdominal fat weight (AFW). This research suggests that apoVLDL-II gene could be a candidate gene that can affect some growth traits in chickens

Volatile components of Camellia sinensis inhibit growth and biofilm formation of oral streptococci in vitro

This study aimed to evaluate the efficacy of semi fermented and non fermented Camellia sinensis extracts (Black and Green tea) and comparison between them against Streptococcus mutans ATCC 25175, S. mitis ATCC 9811 and S. sanguis ATCC 10556 that are responsible for dental caries and bacteremias following dental manipulations. Minimum inhibitory concentrations of both tea extracts were assessed by Well diffusion and Broth dilution methods and examination of cell adherence (Biofilm inhibitory concentrations) was observed on glass slides under phase contrast microscope and colony counts from glass beads. Concentration of 1 mg mL-1 of semi fermented tea extract was completely biofilm inhibitor but biofilm formation by these bacteria was seen 7 days after treatment with 1 mg mL-1 of non fermented Camellia sinensis on glass beads and BIC for oral streptococci treated with this extract was 1.5, 2.5 mg mL-1 of semi fermented and 3 mg mL-1 of non fermented extracts had bactericidal effect on these bacteria. Semi fermented and non fermented Camellia sinensis extracts were able to prevent growth of oral streptococci. Therefore dental caries significantly reduce and the efficiency of semi fermented tea was higher due to rich content of volatile components rather than non fermented extracts. © 2008 Asian Network for Scientific Information

Phage shock protein g, a novel ethanol-induced stress protein in salmonella typhimurium

Exposure to ethanol is a stress condition that Salmonella typhimurium often encounters during its life cycle. Food, beverage, drugs, and cosmetics have a long history of using alcohols to control pathogens. Ethanol is also commonly used for disinfecting medical instruments. This study was conducted to evaluate the ethanol stress variations on the protein profile, cell structure, and serologic features of S. typhimurium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the phage shock protein G (pspG), a new ethanol-induced stress protein in cells adapted to 10% ethanol. The result was confirmed by liquid chromatography-mass spectrometry. The maximum quantity of this 9.02-kDa protein was produced in 12.5% (v/v) of ethanol-treated cultures. Scanning electron microscopy has demonstrated new phenotypic characteristics in bacterial structure. The cells were unable to undergo binary fission. This phenomenon explains the tight attachment of bacteria in a colony. Overall, ethanol extreme stress induced expression of new proteins like PspG and repression of some other proteins in S. typhimurium. These induction and repression processes have inflicted dramatic changes on Salmonella behaviors. © 2008 Springer Science+Business Media, LLC

Erratum to: Nanoparticles Impact the Expression of the Genes Involved in Biofilm Formation in S. aureus, a Model Antimicrobial-Resistant Species

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