Helicobacter pylori release from yeast as a vesicle-encased or free bacterium

Background: Yeast has been suggested as a potent reservoir of H. pylori that facilitates bacterial spread within human populations. What mechanism ensures effective H. pylori release from yeast? Here, H. pylori release from yeast as a vesicle-encased or free bacterium was studied. Materials and methods: Liquid culture of Candida yeast was examined by light, fluorescence and transmission electron microscopy methods to observe the released vesicles. Vesicles were isolated and examined by TEM. Immunogold labeling was used for detection of H. pylori-specific proteins in vesicles� membrane. Free bacterial cells, released from yeast, were separated by immunomagnetic separation and observed by field emission scanning electron microscopy (FESEM). DNA of bead-bound bacteria was used for amplification of H. pylori-16S rDNA. Viability of bead-bound bacteria was examined by live/dead stain and cultivation on Brucella blood agar. Results: Microscopic observations showed that vesicles contained bacterium-like structures. Thin sections showed release of vesicle-encased or free bacterium from yeast. Immunogold labeling revealed occurrence of H. pylori proteins in vesicles� membrane. FESEM showed attachment of H. pylori cells to magnetic beads. Sequencing of 521 bp PCR product confirmed the identity of bead-bound H. pylori. Live/dead staining showed viability of bead-bound H. pylori but the result of culture was negative. Conclusions: Escape of intracellular H. pylori from yeast as a membrane-bound or free bacterium indicates that H. pylori uses safe exit mechanisms that do not damage the host which is the principle of symbiotic associations. In human stomach, certain conditions may stimulate yeast cells to release H. pylori as a vesicle-encased or free bacterium. © 2020 John Wiley & Sons Lt

Hypersonic impact properties of pristine and hybrid single and multi-layer C3N and BC3 nanosheets

Carbon, nitrogen, and boron nanostructures are promising ballistic protection materials due to their low density and excellent mechanical properties. In this study, the ballistic properties of C3N and BC3 nanosheets against hypersonic bullets with Mach numbers greater than 6 were studied. The critical perforation conditions, and thus, the intrinsic impact strength of these 2D materials were determined by simulating ballistic curves of C3N and BC3 monolayers. Furthermore, the energy absorption scaling law with different numbers of layers and interlayer spacing was investigated, for homogeneous or hybrid configurations (alternated stacking of C3N and the BC3). Besides, we created a hybrid sheet using van der Waals bonds between two adjacent sheets based on the hypervelocity impacts of fullerene (C60) molecules utilizing molecular dynamics simulation. As a result, since the higher bond energy between N–C compared to B-C, it was shown that C3N nanosheets have higher absorption energy than BC3. In contrast, in lower impact speeds and before penetration, single-layer sheets exhibited almost similar behavior. Our findings also reveal that in hybrid structures, the C3N layers will improve the ballistic properties of BC3. The energy absorption values with a variable number of layers and variable interlayer distance (X = 3.4 Å and 4X = 13.6 Å) are investigated, for homogeneous or hybrid configurations. These results provide a fundamental understanding of ultra-light multilayered armors' design using nanocomposites based on advanced 2D materials. The results can also be used to select and make 2D membranes and allotropes for DNA sequencing and filtration. © 2021, The Author(s).Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

IgG immune responses to different proteins of Helicobacter Pylori as defined by immunoblot assay

Helicobacter pylori (H.pylori) is an etiologic factor for chronic gastritis and peptic ulcers. Serological testing of H.pylori infection is common in Iran, as other parts of the world. There are geographical variations in the humoral immune response to various H. pylori strains in different parts of the worl. We studied the immunogenic proteins of H.pylori by means of an Immunoblot assay with antigens of H.pylori strains isolated in Iran. Sera of 64 patients suffering from dyspepsia were analyzed to determine antibodlies which were good marker of infection and the antibody patterns associated with peptic ulcer.54 out of 64 dyspeptic patients were infected by H. pylori based on positive culture or positive results of both rapid urease test and direct examination. 14 out of fity-four had peptic ulcers and the rest were catagoriied as patients with non-ulcer dyspepsia. Some of them had multiple erosions in the gut or deodenum. Tweny –two major bands were identified by immunoblot. Of these, IgG antibodies against 10 protients, and they produced immunoreative bands at 14, 16, 22, 26, 32 , 32, 44, 87, 92, 120 Kda. Antibody patterns were not identical in the patients. The presence of at least one band at 14, 16, 22, 26, 32, 35Kda was the best marker of infection(sensitivity, 90% and specificity, 80%) Major serological cross reactions were found at moderate molecular weight bands (50, 52, 54, 60, 66 KDa). The presence of at least one band at 14, 16, 22, 26, 32, 35Kda was the best marker of infection (sensitivity, 90% and specificity, 80%). Major serological crossreactions were found at moderate molerate molecular weight bands (50, 52, 54, 60, 66 KDa). The presence of antibodies to 120 Kda protein (Cag A and 87 Kda Protein (Vac A) were not associated with the presence of peptic ulcers. These were in contradiction to results obtained across Europe and U.S but in agreement with Asian studies. However the presence of at least one band at either 32 or 35 Kda was more frequent in the sera of peptic ulcer patients and non-ulcer dyspeptic patients with erosions (P<0.05). These results could be applicable to design new serological kits. In Iran and could also be used to identify new putative virulence factors for H. pylor

Preparative SDS-PAGE Electroelution for Rapid Purification of Alkyl Hydroperoxide Reductase from Helicobacter pylori

"nBackground: Alkyl hydroperoxide reductase (AhpC) of Helicobacter pylori is considered as a diagnostic antigen. There­fore, this antigen can be used to detect H. pylori infection by stool immunoassays such as ELISA. The aim of this study was to simplify the AhpC protein purification procedures."nMethods: For whole cell protein extraction, the bacterial cells were ruptured by octly-β-D glucopyranoside. The isolation and purification of  AhpC protein were attempted by various techniques including ammonium sulfate precipitation, dialysis, preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and electroelution."nResults:A simple method was used for protein purification AhpC protein. One-dimensional preparative gel electrophoresis allows a single and short purification step; the high resolution capacity of this technique leads to a high level of purity of the protein. Moreover, it avoids contamination by other non-specific proteins which often appear during protein purification by column chromatography."nConclusion: The present method is simple, rapid and makes it possible to preparate AhpC from H. pylor

Mitochondrial DNA (mtDNA) structure of Anopheles superpictus populations in IRAN

Background: Malaria is still one of the main health problems in south and southeast provinces of Iran and recently on average 10,000-30,000 malaria cases were reported annually. Mosquitoes of Anopheles superpictus are one of the main malaria vectors in Iran and have been reported from all areas of the country including central plateau and plains of Alborz and Zagrous Mountains chains, and with low numbers in shore plains of the Persian Gulf and Caspian Sea. There are variations in larval and adult morphological characters and also in vectorial capacity of this species in different areas of Iran. Methods: This study has been conducted to investigate rate of mtDNA variation among various populations of this species in Iran. The sequence variation of an 1512 bp length of mitochondrial DNA (mtDNA) cytochrome oxidase subunits 1 and 2 (COI-COII) and an 708 bp sequences of COI gene were analyzed by PCR-RFLP and PCR-direct sequencing respectively. Results: This study showed that there are considerable variations between and within populations. Rate of variation was 12.3 % between populations and this was 2-5% for within Baluchistan population. Totally 4 haplotypes were observed between populations where 3 occur in Baluchistan and one in other places. Conclusion: This is the first report on existence of various haplotypes in An. superpictus in science, and presumably this species comprising siblings and is a species complex. Further studies need to confirm this result and to determine the relationship between mtDNA haplotypes and their role in malaria transmission in each locality

Extraction and separation of lipopolysaccharide from outer membrane of Helicobacter pylori

Background: Helicobacter pylori (H. pylori) is one of the major causes of peptic ulcer, gastritis and gastric cancer. This bacterium has a special lipopolysaccharide (LPS), which is responsible for its pathogenesis and its high resistance against gastric acid and escape from the human immune system. This property makes it a target for further research and diagnostic goals. In this study, the extraction of the LPS and separation from the outer membrane is required. Methods: The LPS was extracted from the outer membrane, or envelope, of H. pylori obtained from patients suffering from gastritis, gastric ulcer and gastric cancer. LPS extraction was performed using the proteinase K method. SDS-PAGE and silver staining were applied to investigate the electrophoretic pattern of the LPS. This pattern was compared with that of E. coli serotype O111:B4 and Salmonella serotype ATCC 14028. Results: The extracted LPS has a ladder-shaped electrophoretic pattern and the bands are located in three groups: high, medium and low molecular weights. Conclusion: The distribution of the bands of the ladder-shaped electrophoretic pattern is caused by the different number of oligosaccharide chains associated with the LPS. The high molecular weight bands represent S-LPS and the low molecular weight bands represent the R-LPS, which lacks the O-chain

Antimicrobial effectiveness of furazolidone against metronidazole-resistant strains of Helicobacter pylori

The occurrence of strains resistant to metronidazole is causing failure of the 4-drug regimen for eradication of Helicobacter pylori in the Islamic Republic of Iran. This study compared the in vitro efficacy of furazolidone with metronidazole, clarithromycin, amoxicillin and tetracycline in 70 H. pylori isolates from dyspeptic patients. Of the isolates, 33% were resistant to metronidazole but all were susceptible to furazolidone. Furazolidone could be considered as an appropriate substitute for metronidazole for H. pylori infections