scholarly journals The Novel Helicobacter pylori CznABC Metal Efflux Pump Is Required for Cadmium, Zinc, and Nickel Resistance,Urease Modulation, and Gastric Colonization

2006 ◽  
Vol 74 (7) ◽  
pp. 3845-3852 ◽  
Author(s):  
Frank Nils Stähler ◽  
Stefan Odenbreit ◽  
Rainer Haas ◽  
Julia Wilrich ◽  
Arnoud H. M. Van Vliet ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Metal Ion ◽  
Insertional Mutagenesis ◽  
Urease Activity ◽  
Ion Homeostasis ◽  
Metal Ion Homeostasis ◽  
Gastric Colonization ◽  
Nickel Homeostasis ◽  
H Pylori ◽  
Cadmium Zinc

ABSTRACT Maintaining metal homeostasis is crucial for the adaptation of Helicobacter pylori to the gastric environment. Iron, copper, and nickel homeostasis has recently been demonstrated to be required for the establishment of H. pylori infection in animal models. Here we demonstrate that the HP0969-0971 gene cluster encoding the Czc-type metal export pump homologs HP0969, HP0970, and the H. pylori-specific protein HP0971 forms part of a novel H. pylori metal resistance determinant, which is required for gastric colonization and for the modulation of urease activity. Insertional mutagenesis of the HP0971, HP0970, or HP0969 genes in H. pylori reference strain 26695 resulted in increased sensitivity to cadmium, zinc, and nickel (czn), suggesting that the encoded proteins constitute a metal-specific export pump. Accordingly, the genes were designated cznC (HP0971), cznB (HP0970), and cznA (HP0969). The CznC and CznA proteins play a predominant role in nickel homeostasis, since only the cznC and cznA mutants but not the cznB mutant displayed an 8- to 10-fold increase in urease activity. Nickel-specific affinity chromatography demonstrated that recombinant versions of CznC and CznB can bind to nickel and that the purified CznB protein interacted with cadmium and zinc, since both metals competitively inhibited nickel binding. Finally, single cznA, cznB, and cznC mutants did not colonize the stomach in a Mongolian gerbil-based animal model. This demonstrates that the metal export functions of H. pylori cznABC are essential for gastric colonization and underlines the extraordinary importance of metal ion homeostasis for the survival of H. pylori in the gastric environment.

scholarly journals Identification by RNA Profiling and Mutational Analysis of the Novel Copper Resistance Determinants CrdA (HP1326), CrdB (HP1327), and CzcB (HP1328) in Helicobacter pylori

2002 ◽  
Vol 184 (23) ◽  
pp. 6700-6708 ◽  
Author(s):  
Barbara Waidner ◽  
Klaus Melchers ◽  
Igor Ivanov ◽  
Hannes Loferer ◽  
Klaus W. Bensch ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Metal Ion ◽  
Specific Protein ◽  
Copper Resistance ◽  
System Component ◽  
The Novel ◽  
Rna Profiling ◽  
Metal Ion Homeostasis ◽  
Resistance Determinants ◽  
H Pylori

ABSTRACT Mechanisms involved in maintaining cytoplasmic metal ion homeostasis play a central role in the adaptation of Helicobacter pylori to the changing gastric environment. An investigation of the global regulatory responses to copper ions by using RNA profiling with a threshold factor of 4.0 revealed that copper induces transcription of 19 H. pylori genes and that only the ferritin gene pfr is repressed. The 57-fold copper induction identified the HP1326 gene encoding an H. pylori-specific protein as a candidate for a novel copper resistance determinant. The HP1326 gene is expressed as a monocistronic unit, and two small HP1326 mRNAs are copper induced. The HP1326 protein is secreted and is required for copper resistance maintained by cytoplasmic copper homeostasis, as H. pylori HP1326 mutants were copper sensitive and displayed increased copper induction of HP1326 transcription as well as elevated copper repression of ferritin synthesis. The clear copper-sensitive phenotype displayed by H. pylori HP1327 and HP1328 mutants provides strong evidence that the HP1326 protein, together with the signal peptide site of the H. pylori-specific protein HP1327, whose gene is located downstream from that encoding HP1326, and the CzcB and CzcA metal efflux system component homologs HP1328 and HP1329, constitutes a novel type of copper efflux pump, as discussed below. The HP1329 gene could not be inactivated, but the 14-fold transcriptional copper induction determined by RNA profiling points towards a function of the encoded CzcA homolog in copper resistance. In summary, results from RNA profiling identified the novel H. pylori-specific copper resistance determinants CrdA (HP1326) and CrdB (HP1327), which are required for adaptation to copper-rich environmental conditions.

scholarly journals Zerumbone Inhibits Helicobacter pylori Urease Activity

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2663
Author(s):  
Hyun Jun Woo ◽  
Ji Yeong Yang ◽  
Pyeongjae Lee ◽  
Jong-Bae Kim ◽  
Sa-Hyun Kim
Keyword(s):  
Helicobacter Pylori ◽  
Carbon Atom ◽  
Natural Compound ◽  
Urease Activity ◽  
Negative Charge ◽  
Positive Charge ◽  
Gastric Epithelium ◽  
Functional Inhibition ◽  
Electrical Gradient ◽  
H Pylori

Helicobacter pylori (H. pylori) produces urease in order to improve its settlement and growth in the human gastric epithelium. Urease inhibitors likely represent potentially powerful therapeutics for treating H. pylori; however, their instability and toxicity have proven problematic in human clinical trials. In this study, we investigate the ability of a natural compound extracted from Zingiber zerumbet Smith, zerumbone, to inhibit the urease activity of H. pylori by formation of urease dimers, trimers, or tetramers. As an oxygen atom possesses stronger electronegativity than the first carbon atom bonded to it, in the zerumbone structure, the neighboring second carbon atom shows a relatively negative charge (δ−) and the next carbon atom shows a positive charge (δ+), sequentially. Due to this electrical gradient, it is possible that H. pylori urease with its negative charges (such as thiol radicals) might bind to the β-position carbon of zerumbone. Our results show that zerumbone dimerized, trimerized, or tetramerized with both H. pylori urease A and urease B molecules, and that this formation of complex inhibited H. pylori urease activity. Although zerumbone did not affect either gene transcription or the protein expression of urease A and urease B, our study demonstrated that zerumbone could effectively dimerize with both urease molecules and caused significant functional inhibition of urease activity. In short, our findings suggest that zerumbone may be an effective H. pylori urease inhibitor that may be suitable for therapeutic use in humans.

scholarly journals Zinc limitation in Klebsiella pneumoniae profiled by quantitative proteomics influences transcriptional regulation and cation transporter-associated capsule production

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
A. Sukumaran ◽  
S. Pladwig ◽  
J. Geddes-McAlister
Keyword(s):  
Klebsiella Pneumoniae ◽  
Metal Ion ◽  
Ion Homeostasis ◽  
Cellular Protein ◽  
Pcr Analysis ◽  
Phenotypic Analysis ◽  
Metal Ion Homeostasis ◽  
Capsule Production ◽  
The Impact

Abstract Background Microbial organisms encounter a variety of environmental conditions, including changes to metal ion availability. Metal ions play an important role in many biological processes for growth and survival. As such, microbes alter their cellular protein levels and secretion patterns in adaptation to a changing environment. This study focuses on Klebsiella pneumoniae, an opportunistic bacterium responsible for nosocomial infections. By using K. pneumoniae, we aim to determine how a nutrient-limited environment (e.g., zinc depletion) modulates the cellular proteome and secretome of the bacterium. By testing virulence in vitro, we provide novel insight into bacterial responses to limited environments in the presence of the host. Results Analysis of intra- and extracellular changes identified 2380 proteins from the total cellular proteome (cell pellet) and 246 secreted proteins (supernatant). Specifically, HutC, a repressor of the histidine utilization operon, showed significantly increased abundance under zinc-replete conditions, which coincided with an expected reduction in expression of genes within the hut operon from our validating qRT-PCR analysis. Additionally, we characterized a putative cation transport regulator, ChaB that showed significantly higher abundance under zinc-replete vs. -limited conditions, suggesting a role in metal ion homeostasis. Phenotypic analysis of a chaB deletion strain demonstrated a reduction in capsule production, zinc-dependent growth and ion utilization, and reduced virulence when compared to the wild-type strain. Conclusions This is first study to comprehensively profile the impact of zinc availability on the proteome and secretome of K. pneumoniae and uncover a novel connection between zinc transport and capsule production in the bacterial system.

scholarly journals Metallothionein: A Multifunctional Protein from Toxicity to Cancer

2003 ◽  
Vol 18 (3) ◽  
pp. 162-169 ◽  
Author(s):  
S.E. Theocharis ◽  
A.P. Margeli ◽  
A. Koutselinis
Keyword(s):  
Cell Proliferation ◽  
Metal Ion ◽  
Defense Mechanisms ◽  
Ion Homeostasis ◽  
Low Molecular Weight ◽  
Multifunctional Protein ◽  
Metal Ion Homeostasis ◽  
Potential Marker ◽  
Proliferation And Apoptosis ◽  
Carcinogenic Process

The metallothionein (MT) family is a class of low molecular weight, intracellular and cysteine-rich proteins presenting high affinity for metal ions. Although the members of this family were discovered nearly 40 years ago, their functional significance remains obscure. Four major MT isoforms, MT-1, MT-2, MT-3 and MT-4, have been identified in mammals. MTs are involved in many pathophysiological processes such as metal ion homeostasis and detoxification, protection against oxidative damage, cell proliferation and apoptosis, chemoresistance and radiotherapy resistance. MT isoforms have been shown to be involved in several aspects of the carcinogenic process, cancer development and progression. MT expression has been implicated as a transient response to any form of stress or injury providing cytoprotective action. Although MT participates in the carcinogenic process, its use as a potential marker of tumor differentiation or cell proliferation, or as a predictor of poor prognosis remains unclear. In the present review the involvement of MT in defense mechanisms to toxicity and in carcinogenicity is discussed.

scholarly journals The novel ECF56 SigG1-RsfG system modulates morphological differentiation and metal-ion homeostasis in Streptomyces tsukubaensis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rute Oliveira ◽  
Matthew J. Bush ◽  
Sílvia Pires ◽  
Govind Chandra ◽  
Delia Casas-Pastor ◽  
...  
Keyword(s):  
Metal Ion ◽  
Ion Homeostasis ◽  
Morphological Differentiation ◽  
The Novel ◽  
Copper Trafficking ◽  
Streptomyces Tsukubaensis ◽  
Metal Ion Homeostasis ◽  
Σ Factor ◽  
Domain Organisation

AbstractExtracytoplasmic function (ECF) sigma factors are key transcriptional regulators that prokaryotes have evolved to respond to environmental challenges. Streptomyces tsukubaensis harbours 42 ECFs to reprogram stress-responsive gene expression. Among them, SigG1 features a minimal conserved ECF σ2–σ4 architecture and an additional C-terminal extension that encodes a SnoaL_2 domain, which is characteristic for ECF σ factors of group ECF56. Although proteins with such domain organisation are widely found among Actinobacteria, the functional role of ECFs with a fused SnoaL_2 domain remains unknown. Our results show that in addition to predicted self-regulatory intramolecular amino acid interactions between the SnoaL_2 domain and the ECF core, SigG1 activity is controlled by the cognate anti-sigma protein RsfG, encoded by a co-transcribed sigG1-neighbouring gene. Characterisation of ∆sigG1 and ∆rsfG strains combined with RNA-seq and ChIP-seq experiments, suggests the involvement of SigG1 in the morphological differentiation programme of S. tsukubaensis. SigG1 regulates the expression of alanine dehydrogenase, ald and the WhiB-like regulator, wblC required for differentiation, in addition to iron and copper trafficking systems. Overall, our work establishes a model in which the activity of a σ factor of group ECF56, regulates morphogenesis and metal-ions homeostasis during development to ensure the timely progression of multicellular differentiation.

scholarly journals The role of acid inhibition in Helicobacter pylori eradication

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 1747 ◽  
Author(s):  
David R. Scott ◽  
George Sachs ◽  
Elizabeth A. Marcus
Keyword(s):  
Helicobacter Pylori ◽  
Urease Activity ◽  
Eradication Therapy ◽  
Acid Inhibition ◽  
Acid Suppression ◽  
Helicobacter Pylori Eradication ◽  
Ulcer Disease ◽  
Chronic Active Gastritis ◽  
H Pylori

Infection of the stomach by the gastric pathogen Helicobacter pylori results in chronic active gastritis and leads to the development of gastric and duodenal ulcer disease and gastric adenocarcinoma. Eradication of H. pylori infection improves or resolves the associated pathology. Current treatments of H. pylori infection rely on acid suppression in combination with at least two antibiotics. The role of acid suppression in eradication therapy has been variously attributed to antibacterial activity of proton pump inhibitors directly or through inhibition of urease activity or increased stability and activity of antibiotics. Here we discuss the effect of acid suppression on enhanced replicative capacity of H. pylori to permit the bactericidal activity of growth-dependent antibiotics. The future of eradication therapy will rely on improvement of acid inhibition along with current antibiotics or the development of novel compounds targeting the organism’s ability to survive in acid.

scholarly journals The Balance between Life and Death of Cells: Roles of Metallothioneins

2006 ◽  
Vol 1 ◽  
pp. 117727190600100 ◽  
Author(s):  
Allan Evald Nielsen ◽  
Adam Bohr ◽  
Milena Penkowa
Keyword(s):  
Metal Ion ◽  
Molecular Mechanisms ◽  
Energy Levels ◽  
Ion Homeostasis ◽  
Cellular Survival ◽  
Life And Death ◽  
Cellular Energy ◽  
Metal Ion Homeostasis ◽  
Pathological Conditions ◽  
Cysteine Rich Protein

Metallothionein (MT) is a highly conserved, low-molecular-weight, cysteine-rich protein that occurs in 4 isoforms (MT-I to MT-IV), of which MT-I+II are the major and best characterized proteins. This review will focus on mammalian MT-I+II and their functional impact upon cellular survival and death, as seen in two rather contrasting pathological conditions: Neurodegeneration and neoplasms. MT-I+II have analogous functions including: 1) Antioxidant scavenging of reactive oxygen species (ROS); 2) Cytoprotection against degeneration and apoptosis; 3) Stimulation of cell growth and repair including angiogenesis/revascularization, activation of stem/progenitor cells, and neuroregeneration. Thereby, MT-I+II mediate neuroprotection, CNS restoration and clinical recovery during neurodegenerative disorders. Due to the promotion of cell survival, increased MT-I+II levels have been associated with poor tumor prognosis, although the data are less clear and direct causative roles of MT-I+II in oncogenesis remain to be identified. The MT-I+II molecular mechanisms of actions are not fully elucidated. However, their role in metal ion homeostasis might be fundamental in controlling Zn-dependent transcription factors, protein synthesis, cellular energy levels/metabolism and cell redox state. Here, the neuroprotective and regenerative functions of MT-I+II are reviewed, and the presumed link to oncogenesis is critically perused.

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