المؤلفون: Rachel J. Ende, Isabelle Derré

المصدر: Infect Immun

مصطلحات موضوعية: 0301 basic medicine, Chlamydia muridarum, Pyruvate Kinase, 030106 microbiology, Immunology, Chlamydia trachomatis, medicine.disease_cause, Microtubules, Microbiology, 03 medical and health sciences, chemistry.chemical_compound, Bacterial Proteins, Fructose-Bisphosphate Aldolase, Lactate dehydrogenase, medicine, Humans, Pathogen, Inclusion Bodies, Cellular Microbiology: Pathogen-Host Cell Molecular Interactions, Chlamydia, Host Microbial Interactions, L-Lactate Dehydrogenase, biology, Aldolase A, Chlamydia Infections, biology.organism_classification, medicine.disease, Actins, Metabolic pathway, Bacterial Outer Membrane, 030104 developmental biology, Infectious Diseases, chemistry, Protein Biosynthesis, biology.protein, Parasitology, Glycolysis, Bacteria, Pyruvate kinase, HeLa Cells

الوصف: The obligate intracellular pathogen Chlamydia trachomatis is the leading cause of noncongenital blindness and causative agent of the most common sexually transmitted infection of bacterial origin. With a reduced genome, C. trachomatis is dependent on its host for survival, in part due to a need for the host cell to compensate for incomplete bacterial metabolic pathways. However, relatively little is known regarding how C. trachomatis is able to hijack host cell metabolism. In this study, we show that two host glycolytic enzymes, aldolase A and pyruvate kinase, as well as lactate dehydrogenase, are enriched at the C. trachomatis inclusion membrane during infection. Inclusion localization was not species specific, since a similar phenotype was observed with C. muridarum. Time course experiments showed that the number of positive inclusions increased throughout the developmental cycle. In addition, these host enzymes colocalized to the same inclusion, and their localization did not appear to be dependent on sustained bacterial protein synthesis or on intact host actin, vesicular trafficking, or microtubules. Depletion of the host glycolytic enzyme aldolase A resulted in decreased inclusion size and infectious progeny production, indicating a role for host glycolysis in bacterial growth. Finally, quantitative PCR analysis showed that expression of C. trachomatis glycolytic enzymes inversely correlated with host enzyme localization at the inclusion. We discuss potential mechanisms leading to inclusion localization of host glycolytic enzymes and how it could benefit the bacteria. Altogether, our findings provide further insight into the intricate relationship between host and bacterial metabolism during Chlamydia infection.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c283b34e7234808f02a74f95e3540451Test
https://doi.org/10.1128/iai.00545-20Test

المؤلفون: Suzanne M. Michalek, C.C. van der Weijden, T. A. Brooks, C C Harmon, Jacky L. Snoep, Jeffrey D. Hillman

المساهمون: Molecular Cell Physiology

المصدر: Infection and Immunity, 68, 543-549. American Society for Microbiology
Hillman, J D, Brooks, T A, Michalek, S M, Harmon, C C, van der Weijden, C C & Snoep, J L 2000, ' Construction and characterization of an effector strain of streptococcus mutans for replacement therapy of dental caries. ', Infection and Immunity, vol. 68, pp. 543-549 . https://doi.org/10.1128/IAI.68.2.543-549.2000Test

مصطلحات موضوعية: Immunology, Dental Caries, Microbiology, Rats, Sprague-Dawley, Streptococcus mutans, Open Reading Frames, chemistry.chemical_compound, Lactate dehydrogenase, Animals, Lactic Acid, Alcohol dehydrogenase, L-Lactate Dehydrogenase, biology, Strain (chemistry), Effector, Acetoin, Mouth Mucosa, Bacterial Infections, biology.organism_classification, Rats, Inbred F344, Rats, Lactic acid, Open reading frame, Infectious Diseases, chemistry, biology.protein, Parasitology

الوصف: An effector strain has been constructed for use in the replacement therapy of dental caries. Recombinant DNA methods were used to make the Streptococcus mutans supercolonizing strain, JH1140, lactate dehydrogenase deficient by deleting virtually all of the ldh open reading frame (ORF). To compensate for the resulting metabolic imbalance, a supplemental alcohol dehydrogenase activity was introduced by substituting the adhB ORF from Zymomonas mobilis in place of the deleted ldh ORF. The resulting clone, BCS3-L1, was found to produce no detectable lactic acid during growth on a variety of carbon sources, and it produced significantly less total acid due to its increased production of ethanol and acetoin. BCS3-L1 was significantly less cariogenic than JH1140 in both gnotobiotic- and conventional-rodent models. It colonized the teeth of conventional rats as well as JH1140 in both aggressive-displacement and preemptive-colonization models. No gross or microscopic abnormalities of major organs were associated with oral colonization of rats with BCS3-L1 for 6 months. Acid-producing revertants of BCS3-L1 were not observed in samples taken from infected animals (reversion frequency, −3 ) or by screening cultures grown in vitro, where no revertants were observed among 10 5 colonies examined on pH indicator medium. The reduced pathogenic potential of BCS3-L1, its strong colonization potential, and its genetic stability suggest that this strain is well suited to serve as an effector strain in the replacement therapy of dental caries in humans.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::86d5d3305ff79a3fbfd81c2d4def92b4Test
https://doi.org/10.1128/iai.68.2.543-549.2000Test

المؤلفون: Andrea Didier, Maximilian Casteel, Toril Lindbäck, Stefanie Bock, Marianne Sundt Sødring, Carina Nielsen, Annette Fagerlund, Per Einar Granum, Simon P. Hardy, Richard Dietrich, Maximilian Moravek, Erwin Märtlbauer

المصدر: Infection and Immunity. 78:3813-3821

مصطلحات موضوعية: Lysis, Immunology, Bacillus cereus, Priming (immunology), Enterotoxin, medicine.disease_cause, Microbiology, Enterotoxins, Chlorocebus aethiops, medicine, Animals, Cytotoxicity, Vero Cells, Dose-Response Relationship, Drug, L-Lactate Dehydrogenase, biology, Toxin, biology.organism_classification, Molecular Pathogenesis, Infectious Diseases, Biochemistry, Biophysics, Vero cell, Parasitology, Cysteine

الوصف: This study focuses on the interaction of the three components of the Bacillus cereus Nhe enterotoxin with particular emphasis on the functional roles of NheB and NheC. The results demonstrated that both NheB and NheC were able to bind to Vero cells directly while NheA lacked this ability. It was also shown that Nhe-induced cytotoxicity required a specific binding order of the individual components whereby the presence of NheC in the priming step as well as the presence of NheA in the final incubation step was mandatory. Priming of cells with NheB alone and addition of NheA plus NheC in the second step failed to induce toxic effects. Furthermore, in solution, excess NheC inhibited binding of NheB to Vero cells, whereas priming of cells with excess NheC resulted in full toxicity if unbound NheC was removed before addition of NheB. By using mutated NheC proteins where the two cysteine residues in the predicted β-tongue were replaced with glycine (NheC cys− ) or where the entire hydrophobic stretch was deleted (NheC hr− ), the predicted hydrophobic β-tongue of NheC was found essential for binding to cell membranes but not for interaction with NheB in solution. All data presented here are compatible with the following model. The first step in the mode of action of Nhe is associated with binding of NheC and NheB to the cell surface and probably accompanied by conformational changes. These events allow subsequent binding of NheA, leading to cell lysis.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::43c52205675b45630e2629ec83430c58Test
https://doi.org/10.1128/iai.00247-10Test

المؤلفون: Joshua E. Turse, Qingmin Wu, Thomas A. Ficht, Jianwu Pei

المصدر: Infection and Immunity. 74:2667-2675

مصطلحات موضوعية: Programmed cell death, Necrosis, media_common.quotation_subject, Immunology, Brucella abortus, Apoptosis, Brucella, Microbiology, Bacterial cell structure, Cell Line, Mice, Bacterial Proteins, medicine, Animals, Macrophage, Internalization, media_common, Cellular Microbiology: Pathogen-Host Cell Molecular Interactions, L-Lactate Dehydrogenase, biology, Macrophages, Macrophage Activation, biology.organism_classification, Infectious Diseases, Phosphotransferases (Phosphomutases), Protein Biosynthesis, Parasitology, Tumor necrosis factor alpha, medicine.symptom, Brucella melitensis

الوصف: Previous studies suggest that smooth Brucella organisms inhibit macrophage apoptosis. In contrast, necrotic cell death of macrophages infected with rough Brucella organisms in vitro has been reported, which may in part explain the failure of some rough organisms to thrive. To characterize these potential macrophage killing mechanisms, J774.A1 murine macrophages were infected with Brucella abortus S2308-derived rough mutant CA180. Electron microscopic analysis and polyethylene glycol protection assays revealed that the cells were killed as a result of necrosis and oncosis. This killing was shown to be unaffected by treatment with carbenicillin, an inhibitor of bacterial cell wall biosynthesis and, indirectly, replication. In contrast, chloramphenicol treatment of macrophages infected at multiplicities of infection exceeding 10,000 prevented cell death, despite internalization of large numbers of bacteria. Similarly, heat-killed and gentamicin-killed CA180 did not induce cytopathic effects in the macrophage. These results suggested that killing of infected host cells requires active bacterial protein synthesis. Cytochalasin D treatment revealed that internalization of the bacteria was necessary to initiate killing. Transwell experiments demonstrated that cell death is not mediated by a diffusible product, including tumor necrosis factor alpha and nitric oxide, but does require direct contact between host and pathogen. Furthermore, macrophages preinfected with B. abortus S2308 or pretreated with B. abortus O polysaccharide did not prevent rough CA180-induced cell death. In conclusion, Brucella rough mutant infection induces necrotic and oncotic macrophage cell death that requires bacterial protein synthesis and direct interaction of bacteria with the target cells.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f1b62d17458f17d5769ae261e744d133Test
https://doi.org/10.1128/iai.74.5.2667-2675.2006Test

المؤلفون: Benoît Polack, Bertrand Toussaint, Rozen Leberre, Olivier Epaulard, Benoit Guery, Arjan de Groot, Ina Attree, Denis Dacheux

المصدر: Infection and Immunity. 70:3973-3977

مصطلحات موضوعية: Pore Forming Cytotoxic Proteins, Cystic Fibrosis, Histidine Kinase, Neutrophils, Operon, Immunology, Mutant, Pyruvate Dehydrogenase Complex, Dihydrolipoyllysine-Residue Acetyltransferase, medicine.disease_cause, Microbiology, Type three secretion system, Rats, Sprague-Dawley, Bacterial Proteins, Phosphoprotein Phosphatases, Pneumonia, Bacterial, medicine, Animals, Humans, Pseudomonas Infections, Secretion, Cellular Microbiology: Pathogen-Host Cell Molecular Interactions, L-Lactate Dehydrogenase, biology, Pseudomonas aeruginosa, biochemical phenomena, metabolism, and nutrition, biology.organism_classification, Pyruvate dehydrogenase complex, Molecular biology, Rats, DNA-Binding Proteins, Disease Models, Animal, Mutagenesis, Insertional, Infectious Diseases, Pseudomonadales, Trans-Activators, Parasitology, Protein Kinases, Pseudomonadaceae

الوصف: Pseudomonas aeruginosa clinical cystic fibrosis isolate CHA was mutagenized with Tn 5 Tc to identify new genes involved in type III secretion system (TTSS)-dependent cytotoxicity toward human polymorphonuclear neutrophils. Among 25 mutants affected in TTSS function, 14 contained the insertion at different positions in the aceAB operon encoding the PDH-E1 and -E2 subunits of pyruvate dehydrogenase. In PDH mutants, no transcriptional activation of TTSS genes in response to calcium depletion occurred. Expression in trans of ExsA restored TTSS function and cytotoxicity.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ef4ac8c2a06794f5c7364020b1618b0cTest
https://doi.org/10.1128/iai.70.7.3973-3977.2002Test

المؤلفون: K. G. Swihart, G. R. Chippendale, Harry L. T. Mobley, Rodney A. Welch

المصدر: Scopus-Elsevier

مصطلحات موضوعية: Urease, Immunology, Proteus vulgaris, Biology, Hemolysin Proteins, Microbiology, Epithelium, Kidney Tubules, Proximal, chemistry.chemical_compound, Bacterial Proteins, Lactate dehydrogenase, medicine, Humans, Proteus mirabilis, Cells, Cultured, Kidney, L-Lactate Dehydrogenase, Hemagglutination, Hemolysin, biology.organism_classification, Enterobacteriaceae, Infectious Diseases, medicine.anatomical_structure, chemistry, biology.protein, Female, Parasitology, Research Article

الوصف: Proteus mirabilis, a common agent of nosocomially acquired and catheter-associated bacteriuria, can cause acute pyelonephritis. In ascending infections, bacteria colonize the bladder and ascend the ureters to the proximal tubules of the kidney. We postulate that Proteus species uses the HpmA hemolysin and urease to elicit tissue damage that allows entry of these bacteria into the kidney. To study this interaction, strains of Proteus mirabilis and P. vulgaris and their isogenic hemolysin-negative (hpmA) or isogenic urease-negative (ureC) constructs were overlaid onto cultures of human renal proximal tubular epithelial cells (HRPTEC) isolated from kidneys obtained by immediate autopsy. Cytotoxicity was measured by release of soluble lactate dehydrogenase (LDH). Two strains of P. mirabilis inoculated at 10(6) CFU caused a release of 80% of total LDH after 6 h, whereas pyelonephritogenic hemolytic Escherichia coli CFT073 released only 25% at 6 h (P less than 0.012). Ten P. mirabilis isolates and five P. vulgaris isolates were all hemolytic and cytotoxic and produced urease which was induced by urea. The HpmA hemolysin is apparently responsible for the majority of cytotoxicity in vitro since the hemolysin-negative (hpmA) mutants of P. mirabilis and P. vulgaris were significantly less cytotoxic than wild-type strains. P. mirabilis WPM111 (hemolysin negative) was used to test the effect of urease-catalyzed urea hydrolysis on HRPTEC viability. In the presence of 50 mM urea, WPM111 caused the release of 42% of LDH versus 1% at 6 h in the absence of substrate (P = 0.003). We conclude that the HpmA hemolysin of Proteus species acts as a potent cytotoxin against HRPTEC. In addition, urease apparently contributes to this process when substrate urea is available.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::25a022e371e50924b2e74695da2e0dcdTest
https://doi.org/10.1128/iai.59.6.2036-2042.1991Test

المؤلفون: Ellen A. Spotts, C. Harold King, Karen M. Dobos, Frederick D. Quinn

المصدر: Infection and Immunity. 68:6300-6310

مصطلحات موضوعية: Necrosis, Tuberculosis, Immunology, Biology, Microbiology, Permeability, Histones, Mycobacterium tuberculosis, chemistry.chemical_compound, medicine, Humans, Propidium iodide, Cycloheximide, Cytotoxicity, Lung, Cells, Cultured, A549 cell, Mycobacterium bovis, L-Lactate Dehydrogenase, Epithelial Cells, Bacterial Infections, DNA, respiratory system, biology.organism_classification, medicine.disease, respiratory tract diseases, Infectious Diseases, chemistry, Cell culture, Streptomycin, Parasitology, medicine.symptom

الوصف: Mycobacterium tuberculosisestablishes infection, progresses towards disease, and is transmitted from the alveolus of the lung. However, the role of the alveolar epithelium in any of these pathogenic processes of tuberculosis is unclear. In this study, lung epithelial cells (A549) were used as a model in which to examine cytotoxicity during infection with either virulent or avirulent mycobacteria in order to further establish the role of the lung epithelium during tuberculosis. Infection of A549 cells withM. tuberculosisstrains Erdman and CDC1551 demonstrated significant cell monolayer clearing, whereas infection with eitherMycobacterium bovisBCG orMycobacterium smegmatisLR222 did not. Clearing ofM. tuberculosis-infected A549 cells correlated to necrosis, not apoptosis. Treatment ofM. tuberculosis-infected A549 cells with streptomycin, but not cycloheximide, demonstrated a significant reduction in the necrosis of A549 cell monolayers. This mycobacterium-induced A549 necrosis did not correlate to higher levels of intracellular or extracellular growth by the mycobacteria during infection. Staining of infected cells with propidium iodide demonstrated thatM. tuberculosisinduced increased permeation of A549 cell membranes within 24 h postinfection. Quantitation of lactate dehydrogenase (LDH) release from infected cells further demonstrated that cell permeation was specific toM. tuberculosisinfection and correlated to A549 cellular necrosis. InactivatedM. tuberculosisor its subcellular fractions did not result in A549 necrosis or LDH release. These studies demonstrate that lung epithelial cell cytotoxicity is specific to infection by virulent mycobacteria and is caused by cellular necrosis. This necrosis is not a direct correlate of mycobacterial growth or of the expression of host cell factors, but is preceded by permeation of the A549 cell membrane and requires infection with live bacilli.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f551e35d9eda257be8a5d8743029bd1bTest
https://doi.org/10.1128/iai.68.11.6300-6310.2000Test

المؤلفون: Mark S. McClain, Susan E. Ivie, Timothy L. Cover, Christian González-Rivera, Jana N. Radin

المصدر: Infection and immunity. 79(7)

مصطلحات موضوعية: Programmed cell death, Peptic Ulcer, Necrosis, Virulence Factors, Poly ADP ribose polymerase, Immunology, Bacterial Toxins, Blotting, Western, Microbiology, Ion Channels, Proinflammatory cytokine, Cell Line, Adenosine Triphosphate, Bacterial Proteins, Stomach Neoplasms, Cell Line, Tumor, medicine, Gastric mucosa, Humans, HMGB1 Protein, Caspase, biology, Cell Death, Helicobacter pylori, L-Lactate Dehydrogenase, Epithelial Cells, biology.organism_classification, bacterial infections and mycoses, Molecular Pathogenesis, digestive system diseases, Infectious Diseases, medicine.anatomical_structure, Gastric Mucosa, Caspases, Gastritis, biology.protein, Parasitology, medicine.symptom, Poly(ADP-ribose) Polymerases

الوصف: Helicobacter pylori is a Gram-negative bacterium that colonizes the human stomach and contributes to the development of peptic ulcer disease and gastric cancer. The secreted pore-forming toxin VacA is one of the major virulence factors of H. pylori . In the current study, we show that AZ-521 human gastric epithelial cells are highly susceptible to VacA-induced cell death. Wild-type VacA causes death of these cells, whereas mutant VacA proteins defective in membrane channel formation do not. Incubation of AZ-521 cells with wild-type VacA results in cell swelling, poly(ADP-ribose) polymerase (PARP) activation, decreased intracellular ATP concentration, and lactate dehydrogenase (LDH) release. VacA-induced death of these cells is a caspase-independent process that results in cellular release of histone-binding protein high mobility group box 1 (HMGB1), a proinflammatory protein. These features are consistent with the occurrence of cell death through a programmed necrosis pathway and suggest that VacA can be included among the growing number of bacterial pore-forming toxins that induce cell death through programmed necrosis. We propose that VacA augments H. pylori -induced mucosal inflammation in the human stomach by causing programmed necrosis of gastric epithelial cells and subsequent release of proinflammatory proteins and may thereby contribute to the pathogenesis of gastric cancer and peptic ulceration.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b3a9f4af8232d97d5cfd8212c4db8df5Test
https://pubmed.ncbi.nlm.nih.gov/21482684Test

المؤلفون: Luke D. Handke, Paul M. Dunman, Paul D. Fey, Michael E. Olson, T. J. Jerrells, Mark E. Rupp, K. L. Rogers, Greg A. Somerville

المصدر: Infection and immunity. 76(1)

مصطلحات موضوعية: Male, Time Factors, Transcription, Genetic, Immunology, Mutant, Virulence, medicine.disease_cause, Microbiology, chemistry.chemical_compound, Mice, Bacterial Proteins, Staphylococcus epidermidis, Lactate dehydrogenase, medicine, Animals, Anaerobiosis, Inflammation, biology, Effector, Gene Expression Profiling, Gene Expression Regulation, Bacterial, Staphylococcal Infections, biology.organism_classification, Molecular Pathogenesis, Infectious Diseases, chemistry, Staphylococcus aureus, Mutation, Parasitology, NAD+ kinase, Bacteria, Transcription Factors

الوصف: The saeRS two-component regulatory system regulates transcription of multiple virulence factors in Staphylococcus aureus . In the present study, we demonstrated that the saePQRS region in Staphylococcus epidermidis is transcriptionally regulated in a temporal manner and is arranged in a manner similar to that previously described for S. aureus . Studies using a mouse foreign body infection model demonstrated that the virulence of strain 1457 and the virulence of a mutant, strain 1457 saeR , were statistically equivalent. However, histological analyses suggested that the polymorphonuclear neutrophil response at 2 days postinfection was significantly greater in 1457-infected mice than in 1457 saeR -infected mice, demonstrating that SaeR influences the early, acute phases of infection. Microarray analysis demonstrated that a saeR mutation affected the transcription of 65 genes (37 genes were upregulated and 28 genes were downregulated); in particular, 8 genes that facilitate growth under anaerobic conditions were downregulated in 1457 saeR . Analysis of growth under anaerobic conditions demonstrated that 1457 saeR had a decreased growth rate compared to 1457. Further metabolic experiments demonstrated that 1457 saeR had a reduced capacity to utilize nitrate as a terminal electron acceptor and exhibited increased production of lactic acid in comparison to 1457. These data suggest that in S. epidermidis SaeR functions to regulate the transition between aerobic growth and anaerobic growth. In addition, when grown anaerobically, 1457 saeR appeared to compensate for the redox imbalance created by the lack of electron transport-mediated oxidation of NADH to NAD + by increasing lactate dehydrogenase activity and the subsequent oxidation of NADH.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::51fe4be90798d3bb8a75f001798c3156Test
https://pubmed.ncbi.nlm.nih.gov/17954724Test

المؤلفون: Colin A. Forestal, David G. Thanassi, Martha B. Furie, Horacio Gil, John W. Rasmussen, Jorge L. Benach, Jeronimo Cello

المصدر: Infection and immunity. 74(12)

مصطلحات موضوعية: Pathology, medicine.medical_specialty, Necrosis, Immunology, Macrophage-1 Antigen, Apoptosis, Mice, Inbred Strains, Biology, Major histocompatibility complex, Microbiology, Lesion, Tularemia, chemistry.chemical_compound, Mice, Lactate dehydrogenase, medicine, Animals, Francisella tularensis, Granuloma, Macrophages, Histocompatibility Antigens Class II, Bacterial Infections, biology.organism_classification, medicine.disease, Molecular biology, Infectious Diseases, chemistry, Liver, biology.protein, Parasitology, Female, Receptors, Chemokine, medicine.symptom, Biomarkers

الوصف: The cell composition of early hepatic lesions of experimental murine tularemia has not been characterized with specific markers. The appearance of multiple granulomatous-necrotic lesions in the liver correlates with a marked increase in the levels of serum alanine transferase and lactate dehydrogenase.Francisella tularensis, detected by specific antibodies, can be first noted by day 1 and becomes associated with the lesions by 5 days postinoculation. These lesions become necrotic, with some evidence of in situ apoptosis. The lesions do not contain B, T, or NK cells. Rather, the lesions are largely composed of two subpopulations of Mac-1+cells that are associated with the bacteria. Gr-1+Mac-1+immature myeloid cells and major histocompatibility complex class II-positive (MHC-II+) Mac-1+macrophages were the most abundant cell phenotypes found in the granuloma and are likely major contributors in controlling the infection in its early stages. Our findings have shown that there is an early development of hepatic lesions whereF. tularensiscolocalizes with both Gr-1+Mac-1+and MHC-II+Mac-1+cells.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ec618bfa23d10a42dea0b1d1213ddd1bTest
https://pubmed.ncbi.nlm.nih.gov/17000726Test