scholarly journals Phytogenic synthesis of silver nanobactericides for anti-biofilm activity against human pathogen H. pylori

2019 ◽  
Vol 1 (4) ◽  
Author(s):  
Ashwini Prasad ◽  
Syed Baker ◽  
M. N. Nagendra Prasad ◽  
Aishwarya Tripurasundari Devi ◽  
S. Satish ◽  
...  
Keyword(s):  
Human Pathogen ◽  
H Pylori ◽  
Phytogenic Synthesis

scholarly journals The Helicobacter pylori Homologue of the Ferric Uptake Regulator Is Involved in Acid Resistance

2002 ◽  
Vol 70 (2) ◽  
pp. 606-611 ◽  
Author(s):  
Jetta J. E. Bijlsma ◽  
Barbara Waidner ◽  
Arnoud H. M. van Vliet ◽  
Nicky J. Hughes ◽  
Stephanie Häg ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Iron Homeostasis ◽  
Regulatory Protein ◽  
Acid Resistance ◽  
Low Ph ◽  
Main Function ◽  
Ferric Uptake Regulator ◽  
Acidic Ph ◽  
Human Pathogen ◽  
H Pylori

ABSTRACT The only known niche of the human pathogen Helicobacter pylori is the gastric mucosa, where large fluctuations of pH occur, indicating that the bacterial response and resistance to acid are important for successful colonization. One of the few regulatory proteins in the H. pylori genome is a homologue of the ferric uptake regulator (Fur). In most bacteria, the main function of Fur is the regulation of iron homeostasis. However, in Salmonella enterica serovar Typhimurium, Fur also plays an important role in acid resistance. In this study, we determined the role of the H. pylori Fur homologue in acid resistance. Isogenic fur mutants were generated in three H. pylori strains (1061, 26695, and NCTC 11638). At pH 7 there was no difference between the growth rates of mutants and the parent strains. Under acidic conditions, growth of the fur mutants was severely impaired. No differences were observed between the survival of the fur mutant and parent strain 1061 after acid shock. Addition of extra iron or removal of iron from the growth medium did not improve the growth of the fur mutant at acidic pH. This indicates that the phenotype of the fur mutant at low pH was not due to increased iron sensitivity. Transcription of fur was repressed in response to low pH. From this we conclude that Fur is involved in the growth at acidic pH of H. pylori; as such, it is the first regulatory protein implicated in the acid resistance of this important human pathogen.

scholarly journals A Gastric Pathogen Moves Chemotaxis in a New Direction

mBio ◽  
2011 ◽  
Vol 2 (5) ◽  
Author(s):  
Emily Goers Sweeney ◽  
Karen Guillemin
Keyword(s):  
Escherichia Coli ◽  
Helicobacter Pylori ◽  
Chemical Cues ◽  
Swimming Behavior ◽  
Human Pathogen ◽  
Gastric Glands ◽  
Content Type ◽  
Gastric Pathogen ◽  
H Pylori ◽  
Novel Antibiotics

ABSTRACTFor almost 50 years,Escherichia colihas been the model for understanding how bacteria orient their movement in response to chemical cues, but recent studies of chemotaxis in other bacteria have revealed interesting variations from prevailing paradigms. Investigating the human pathogenHelicobacter pylori, Amieva and colleagues [mBio 2(4):e00098-11, 2011] discovered a new chemotaxis regulator, ChePep, which modulates swimming behavior through the canonical histidine-aspartate phosphorelay system. Functionally conserved among the epsilonproteobacteria, ChePep is essential forH. pylorito navigate deep into the stomach’s gastric glands and may be an attractive target for novel antibiotics.

scholarly journals Helicobacter pylori FabX contains a [4Fe-4S] cluster essential for unsaturated fatty acid synthesis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiashen Zhou ◽  
Lin Zhang ◽  
Liping Zeng ◽  
Lu Yu ◽  
Yuanyuan Duan ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Unsaturated Fatty Acids ◽  
Acyl Carrier Protein ◽  
Acid Synthesis ◽  
Active Site Residue ◽  
Human Pathogen ◽  
Membrane Phospholipids ◽  
Functional Membrane ◽  
H Pylori ◽  
Positively Charged

AbstractUnsaturated fatty acids (UFAs) are essential for functional membrane phospholipids in most bacteria. The bifunctional dehydrogenase/isomerase FabX is an essential UFA biosynthesis enzyme in the widespread human pathogen Helicobacter pylori, a bacterium etiologically related to 95% of gastric cancers. Here, we present the crystal structures of FabX alone and in complexes with an octanoyl-acyl carrier protein (ACP) substrate or with holo-ACP. FabX belongs to the nitronate monooxygenase (NMO) flavoprotein family but contains an atypical [4Fe-4S] cluster absent in all other family members characterized to date. FabX binds ACP via its positively charged α7 helix that interacts with the negatively charged α2 and α3 helices of ACP. We demonstrate that the [4Fe-4S] cluster potentiates FMN oxidation during dehydrogenase catalysis, generating superoxide from an oxygen molecule that is locked in an oxyanion hole between the FMN and the active site residue His182. Both the [4Fe-4S] and FMN cofactors are essential for UFA synthesis, and the superoxide is subsequently excreted by H. pylori as a major resource of peroxide which may contribute to its pathogenic function in the corrosion of gastric mucosa.

scholarly journals Helicobacter pylori Association with Amoeba: A Natural Reservoir of the Bacteria?

2012 ◽  
Vol 18 (S5) ◽  
pp. 27-28
Author(s):  
A. P. Alves de Matos ◽  
F. F. Vale ◽  
J. M. B. Vitor
Keyword(s):  
Helicobacter Pylori ◽  
Aquatic Environments ◽  
Human Pathogen ◽  
Human Pathogens ◽  
Natural Reservoir ◽  
Hospital Acquired Infections ◽  
Route Of Transmission ◽  
Mode Of Transmission ◽  
H Pylori ◽  
Hospital Acquired

Helicobacter pylori is a human pathogen involved in gastritis and gastric cancer whose mode of transmission remains unknown. Association of H. pylori with humans is thought to date from remote antiquity and the bacterium has apparently evolved together with the human host. A few studies have shown the presence of H. pylori in aquatic environments, which might provide a route of transmission of the bacteria to humans. A recent study has also disclosed the association of the bacteria with Acantamoeba castellanii. Amoeba are known to harbor and promote the persistence of several human pathogens in the environment, representing a significant source of contamination in community and hospital acquired infections.

scholarly journals Extradigestive Manifestation of Helicobacter Pylori Infection in Children and Adolescents

2005 ◽  
Vol 19 (7) ◽  
pp. 421-424 ◽  
Author(s):  
Philip M Sherman ◽  
Frank YH Lin
Keyword(s):  
Helicobacter Pylori ◽  
Molecular Mimicry ◽  
Case Reports ◽  
Case Series ◽  
Helicobacter Pylori Infection ◽  
Deficiency Anemia ◽  
Extraintestinal Manifestations ◽  
Human Pathogen ◽  
Chronic Active Gastritis ◽  
H Pylori

Helicobacter pylori infection fulfills each of Koch's postulates as a human pathogen causing chronic active gastritis. Disease consequences that develop in a subset of infected subjects include peptic ulcerations, gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. More recently, multiple publications have advocated a role for H pylori infection in causing a variety of extraintestinal manifestations. Many of these reports suffer from being case reports or case series without adequate controls. As a result, purported manifestations may simply be coincidental in nature. On the other hand, increasing evidence supports H pylori infection as a cause of sideropenic (refractory iron deficiency) anemia. Moderate evidence supports H pylori gastric infection as a cause of some cases of immune thrombocytopenic purpura due to molecular mimicry. Guidelines should be adjusted in accordance with advancing knowledge in the field.

Association between Helicobacter pylori and open angle glaucoma: current perspective

1970 ◽  
Vol 1 (2) ◽  
pp. 129-135 ◽  
Author(s):  
M Zaidi ◽  
FA Jilani ◽  
Y Gupta ◽  
S Umair ◽  
M Gupta
Keyword(s):  
Nitric Oxide ◽  
Helicobacter Pylori ◽  
Free Radicals ◽  
Oxygen Free Radicals ◽  
Open Angle Glaucoma ◽  
Open Angle ◽  
Human Pathogen ◽  
Gram Negative ◽  
Current Perspective ◽  
H Pylori

Helicobacter pylori is a Gram negative, spiral-shaped, strictly micro-aerophilic and flagellate human pathogen that can inhabit many areas of stomach. H. pylori infection leads to the generation of oxygen free radicals. H. pylori infection might also aggravate the course of glaucoma by increasing the levels of nitric oxide, endothelin-1 and free radicals indirectly. This article briefly reviews the current perspectives on this issue. Keywords: Helicobacter pylori; glaucoma; free radicals DOI: 10.3126/nepjoph.v1i2.3688 Nep J Oph 2009;1(2):129-135

The rod-to-coccoid body transformation in cultures of Helicobacter pylori

1990 ◽  
Vol 48 (3) ◽  
pp. 626-627
Author(s):  
A. R. Crooker ◽  
W. G. Kraft ◽  
T. L. Beard ◽  
M. C. Myers
Keyword(s):  
Helicobacter Pylori ◽  
Growth Cycle ◽  
Negative Bacterium ◽  
Body Formation ◽  
Coccoid Form ◽  
Spiral Form ◽  
Prolonged Culture ◽  
H Pylori ◽  
Upper Gastrointestinal

Helicobacter pylori is a microaerophilic, gram-negative bacterium found in the upper gastrointestinal tract of humans. There is strong evidence that H. pylori is important in the etiology of gastritis; the bacterium may also be a major predisposing cause of peptic ulceration. On the gastric mucosa, the organism exists as a spiral form with one to seven sheathed flagella at one (usually) or both poles. Short spirals were seen in the first successful culture of the organism in 1983. In 1984, Marshall and Warren reported a coccoid form in older cultures. Since that time, other workers have observed rod and coccal forms in vitro; coccoid forms predominate in cultures 3-7 days old. We sought to examine the growth cycle of H. pylori in prolonged culture and the mode of coccoid body formation.

Vacuoles Induced in Mammalian Cells by Helicobacter Cytotoxin are Acidic Organelles

1990 ◽  
Vol 48 (3) ◽  
pp. 168-169
Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich
Keyword(s):  
Acridine Orange ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ulcer Disease ◽  
Gastroduodenal Disease ◽  
H Pylori

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.

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