scholarly journals Essential roles of methionine andS-adenosylmethionine in the autarkic lifestyle ofMycobacterium tuberculosis

2015 ◽  
Vol 112 (32) ◽  
pp. 10008-10013 ◽  
Author(s):  
Michael Berney ◽  
Linda Berney-Meyer ◽  
Ka-Wing Wong ◽  
Bing Chen ◽  
Mei Chen ◽  
...  
Keyword(s):  
Cell Death ◽  
Single Molecule ◽  
Time Course ◽  
Target Space ◽  
Gene Encoding ◽  
Rapid Clearance ◽  
Immunocompromised Mice ◽  
Biotin Supplementation ◽  
Homoserine Transacetylase

Multidrug resistance, strong side effects, and compliance problems in TB chemotherapy mandate new ways to killMycobacterium tuberculosis(Mtb). Here we show that deletion of the gene encoding homoserine transacetylase (metA) inactivates methionine andS-adenosylmethionine (SAM) biosynthesis inMtband renders this pathogen exquisitely sensitive to killing in immunocompetent or immunocompromised mice, leading to rapid clearance from host tissues.MtbΔmetAis unable to proliferate in primary human macrophages, and in vitro starvation leads to extraordinarily rapid killing with no appearance of suppressor mutants. Cell death ofMtbΔmetAis faster than that of other auxotrophic mutants (i.e., tryptophan, pantothenate, leucine, biotin), suggesting a particularly potent mechanism of killing. Time-course metabolomics showed complete depletion of intracellular methionine and SAM. SAM depletion was consistent with a significant decrease in methylation at the DNA level (measured by single-molecule real-time sequencing) and with the induction of several essential methyltransferases involved in biotin and menaquinone biosynthesis, both of which are vital biological processes and validated targets of antimycobacterial drugs.MtbΔmetAcould be partially rescued by biotin supplementation, confirming a multitarget cell death mechanism. The work presented here uncovers a previously unidentified vulnerability ofMtb—the incapacity to scavenge intermediates of SAM and methionine biosynthesis from the host. This vulnerability unveils an entirely new drug target space with the promise of rapid killing of the tubercle bacillus by a new mechanism of action.

An in vitro study of Hoechst 33342 redistribution and its effects on cell viability

2005 ◽  
Vol 24 (11) ◽  
pp. 573-580 ◽  
Author(s):  
N Mohorko ◽  
N Kregar-Velikonja ◽  
G Repovs ◽  
M Gorensek ◽  
M Bresjanac
Keyword(s):  
Cell Death ◽  
Cell Transplantation ◽  
Fluorescence Intensity ◽  
Time Course ◽  
In Vitro Study ◽  
Host Cells ◽  
Hoechst 33342 ◽  
Overnight Incubation ◽  
Donor Cells

Although Hoechst 33342 (H342) is frequently used to label donor cells in cell transplantation research, it has been noted that it might secondarily label the host cells. Furthermore, its potential toxicity leading to cell death has been described. We studied the time course of H342 redistribution from the primary labeled rat bone marrow stromal cells (rBMSC) into the non-labeled rBMSC population over 7 days in culture; we evaluated the nuclear H342 fluorescence intensity as a possible criterion for distinguishing the primary from the secondary labeled cells, and determined the viability of rBMSC after an overnight incubation in 1 mg/mL of H342. H342 labeled / 50% of the initially non-labeled cells within the first 6 hours and almost 90% within a week.Nuclear fluorescence intensity was a reliable criterion for distinguishing primary and secondary labeled cells within the first 24 hours, but less so at later time points. The percentage of either apoptotic or necrotic cells did not rise acutely after the overnight incubation in 1 mg/mL of H342. Although a 12-hour incubation of rBMSC in 1 mg/mL of H342 did not cause acute cell death, H342 rapidly and extensively redistributed into non-labeled cells, which makes H342 a relatively unsuitable marker for cell transplantation research.

scholarly journals Differential Expression of the Aspergillus fumigatus pksP Gene Detected In Vitro and In Vivo with Green Fluorescent Protein

2001 ◽  
Vol 69 (10) ◽  
pp. 6411-6418 ◽  
Author(s):  
Kim Langfelder ◽  
Bruno Philippe ◽  
Bernhard Jahn ◽  
Jean-Paul Latgé ◽  
Axel A. Brakhage
Keyword(s):  
Green Fluorescent Protein ◽  
Aspergillus Fumigatus ◽  
Polyketide Synthase ◽  
Fluorescent Protein ◽  
Developmental Stages ◽  
Gene Encoding ◽  
Immunocompromised Mice ◽  
Green Fluorescent

ABSTRACT Aspergillus fumigatus is an important pathogen of immunocompromised hosts, causing pneumonia and invasive disseminated disease with high mortality. To be able to analyze the expression of putative virulence-associated genes of A. fumigatus, the use of the enhanced green fluorescent protein (EGFP) as a reporter was established. Two 5′ sequences, containing the putative promoters of thepyrG gene, encoding orotidine-5′-phosphate decarboxylase, and the pksP gene, encoding a polyketide synthase involved in both pigment biosynthesis and virulence ofA. fumigatus, were fused with the egfpgene. The PpksP-egfp construct was integrated via homologous recombination into the genomicpksP locus. EGFP production was analyzed by fluorescence spectrometry, Western blot analysis, and fluorescence microscopy. Differential gene expression in A. fumigatus was observed. Fluorescence derived from the PYRG-EGFP fusion protein was detected during all developmental stages of the fungus, i.e., during germination, during vegetative growth, in conidiophores, and weakly in conidia. In addition, it was also detected in germinating conidia when isolated from the lungs of immunocompromised mice. By contrast, PKSP-EGFP-derived fluorescence was not found in hyphae or stalks of conidiophores but was found in phialides and conidia in vitro when the fungus was grown under standard conditions, indicating a developmentally controlled expression of the gene. Interestingly,pksP-egfp expression was also detected in hyphae of germinating conidia isolated from the lungs of immunocompromised mice. This finding indicates that thepksP gene can also be expressed in hyphae under certain conditions and, furthermore, that the pksP gene might also contribute to invasive growth of the fungus.

scholarly journals Nitro-Oxidative Stress after Neuronal Ischemia Induces Protein Nitrotyrosination and Cell Death

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Marta Tajes ◽  
Gerard ILL-Raga ◽  
Ernest Palomer ◽  
Eva Ramos-Fernández ◽  
Francesc X. Guix ◽  
...  
Keyword(s):  
Cell Death ◽  
Time Course ◽  
Primary Cultures ◽  
Blood Perfusion ◽  
No Production ◽  
Irreversible Damage ◽  
No Donor ◽  
Human Neuroblastoma ◽  
Ischemic Tissue

Ischemic stroke is an acute vascular event that obstructs blood supply to the brain, producing irreversible damage that affects neurons but also glial and brain vessel cells. Immediately after the stroke, the ischemic tissue produces nitric oxide (NO) to recover blood perfusion but also produces superoxide anion. These compounds interact, producing peroxynitrite, which irreversibly nitrates protein tyrosines. The present study measured NO production in a human neuroblastoma (SH-SY5Y), a murine glial (BV2), a human endothelial cell line (HUVEC), and in primary cultures of human cerebral myocytes (HC-VSMCs) after experimental ischemiain vitro. Neuronal, endothelial, and inducible NO synthase (NOS) expression was also studied up to 24 h after ischemia, showing a different time course depending on the NOS type and the cells studied. Finally, we carried out cell viability experiments on SH-SY5Y cells withH2O2, a prooxidant agent, and with a NO donor to mimic ischemic conditions. We found that both compounds were highly toxic when they interacted, producing peroxynitrite. We obtained similar results when all cells were challenged with peroxynitrite. Our data suggest that peroxynitrite induces cell death and is a very harmful agent in brain ischemia.

scholarly journals The formation of ceramide from sphingomyelin is associated with cellular apoptosis.

1998 ◽  
Vol 45 (2) ◽  
pp. 287-297 ◽  
Author(s):  
G Dawson ◽  
R Goswami ◽  
J Kilkus ◽  
D Wiesner ◽  
S Dawson
Keyword(s):  
Cell Death ◽  
Growth Factors ◽  
Time Course ◽  
Pi3 Kinase ◽  
Normal Brain ◽  
Dorsal Root Ganglion Cell ◽  
Vitro Assay ◽  
Neutral Sphingomyelinase ◽  
Wehi 231

The apoptotic response of the immature B-cell to the cross-linking of surface IgM receptors provides a good model for cell death and we show in WEHI-231 B-cells that the time course of apoptosis corresponds to the increased formation of ceramide, as measured either by mass (using the diacylglycerol kinase method) or radiolabelling with [3H]palmitate. Inhibitors of sphingosine biosynthesis have no effect on cell death induced by anti-IgM in WEHI-231 but inhibitors of ceramidase accelerate apoptosis, suggesting that activation of sphingomyelinase is the key event in apoptosis. We have demonstrated this by in vitro assay of neutral sphingomyelinase. Apoptosis is also important in normal brain development and neuronal survival is dependent upon phosphatidylinositol 3-kinase (PI3-kinase) activation by growth factors (insulin, nerve growth factor etc.). Withdrawal of these growth factors or inhibition of PI3-kinase with wortmannin or LY294002 activated the pro-apoptotic CPP32 (Yama/Apopain/caspase 3, EC 3.4.22), activated neutral sphingomyelinase and increased ceramide formation in an immortalized dorsal root ganglion cell line F-11. Protection against apoptosis can be achieved by overexpression of the bc12 family of proteins or addition of drugs which elevate cAMP levels. cAMP protects against apoptosis induced by either wortmannin or staurosporine. The specificity for cAMP was confirmed by showing protection with the specific agonist (Sp)cAMPS and increased killing with the antagonist (Rp)cAMPS. However, cAMP did not protect against ceramide killing, suggesting that there are at least two major pathways of apoptosis in neuronal cells.

scholarly journals Establishment of an in vitro system for studies on the induced resistance of cotton to Xanthomonas campestris pv. malvacearum

2000 ◽  
Vol 35 (4) ◽  
pp. 719-725 ◽  
Author(s):  
ADILSON KENJI KOBAYASHI ◽  
LUIZ GONZAGA ESTEVES VIEIRA
Keyword(s):  
Cell Death ◽  
Xanthomonas Campestris ◽  
Time Course ◽  
Cell Suspension Cultures ◽  
Suspension Cultures ◽  
Extracellular Polysaccharides ◽  
Protein Accumulation ◽  
Resistance Response ◽  
In Vitro System

An in vitro system for studying the resistance response of cotton (Gossypium hirsutum L.) to Xanthomonas campestris pv. malvacearum was investigated. Cell suspension cultures, established from hypocotyl-derived callus of cotton cultivar 101-102B, were treated with bacterial extracellular polysaccharides (EPS) extracted from the incompatible race 18 of X. campestris pv. malvacearum. EPS at 600 mug/mL caused pronounced darkening of the suspension cultures, as indicative of cell death, 48 hours after incubation. Protein electrophoresis analysis of the time course of EPS-treated cells showed differential accumulation of several protein bands after 12-24 hours. The time course of protein accumulation and cell death was consistent with an elicitor-mediated hypersensitive response.

scholarly journals Molecular signature of anastasis for reversal of apoptosis

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 43 ◽  
Author(s):  
Ho Man Tang ◽  
C. Conover Talbot Jr ◽  
Ming Chiu Fung ◽  
Ho Lam Tang
Keyword(s):  
Gene Expression ◽  
Cell Death ◽  
Time Course ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Molecular Signature ◽  
Cell Recovery ◽  
Therapeutic Implications

Apoptosis is a type of programmed cell death that is essential for normal organismal development and homeostasis of multicellular organisms by eliminating unwanted, injured, or dangerous cells. This cell suicide process is generally assumed to be irreversible. However, accumulating studies suggest that dying cells can recover from the brink of cell death. We recently discovered an unexpected reversibility of the execution-stage of apoptosis in vitro and in vivo, and proposed the term anastasis (Greek for “rising to life”) to describe this cell recovery phenomenon. Promoting anastasis could in principle preserve injured cells that are difficult to replace, such as cardiomyocytes and neurons. Conversely, arresting anastasis in dying cancer cells after cancer therapies could improve treatment efficacy. To develop new therapies that promote or inhibit anastasis, it is essential to identify the key regulators and mediators of anastasis – the therapeutic targets. Therefore, we performed time-course microarray analysis to explore the molecular mechanisms of anastasis during reversal of ethanol-induced apoptosis in mouse primary liver cells. We found striking changes in transcription of genes involved in multiple pathways, including early activation of pro-survival genes, cell cycle arrest, stress-inducible responses, and at delayed times, cell migration and angiogenesis. Here, we present the time-course whole-genome gene expression dataset revealing gene expression profiles during the reversal of apoptosis. This dataset provides important insights into the physiological, pathological, and therapeutic implications of anastasis.

Comparison of High Purity Factor IX Concentrates and a Prothrombin Complex Concentrate in a Canine Model of Thrombogenicity

1991 ◽  
Vol 66 (05) ◽  
pp. 609-613 ◽  
Author(s):  
I R MacGregor ◽  
J M Ferguson ◽  
L F McLaughlin ◽  
T Burnouf ◽  
C V Prowse
Keyword(s):  
High Purity ◽  
Time Course ◽  
Prothrombin Complex Concentrate ◽  
Degradation Products ◽  
Canine Model ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Albumin Infusion

SummaryA non-stasis canine model of thrombogenicity has been used to evaluate batches of high purity factor IX concentrates from 4 manufacturers and a conventional prothrombin complex concentrate (PCC). Platelets, activated partial thromboplastin time (APTT), fibrinogen, fibrin(ogen) degradation products and fibrinopeptide A (FPA) were monitored before and after infusion of concentrate. Changes in FPA were found to be the most sensitive and reproducible indicator of thrombogenicity after infusion of batches of the PCC at doses of between 60 and 180 IU/kg, with a dose related delayed increase in FPA occurring. Total FPA generated after 100-120 IU/kg of 3 batches of PCC over the 3 h time course was 9-12 times that generated after albumin infusion. In contrast the amounts of FPA generated after 200 IU/kg of the 4 high purity factor IX products were in all cases similar to albumin infusion. It was noted that some batches of high purity concentrates had short NAPTTs indicating that current in vitro tests for potential thrombogenicity may be misleading in predicting the effects of these concentrates in vivo.

Functional Properties of p-Anisoylated Plasmin-Staphylokinase Complex

1993 ◽  
Vol 70 (02) ◽  
pp. 326-331 ◽  
Author(s):  
H R Lijnen ◽  
B Van Hoef ◽  
R A G Smith ◽  
D Collen
Keyword(s):  
Human Plasma ◽  
Rate Constant ◽  
Time Course ◽  
Bolus Injection ◽  
Similar Rate ◽  
Clot Lysis ◽  
Lag Phase ◽  
Plasma Clot ◽  
Rapid Clearance ◽  
Stoichiometric Complex

SummaryThe kinetic and fibrinolytic properties of a reversibly acylated stoichiometric complex between human plasmin and recombinant staphylokinase (plasmin-STAR complex) were evaluated. The acylation rate constant of plasmin-STAR by p-amidinophenyl-p’-anisate-HCI was 52 M-1 s-1 and its deacylation rate constant 1.2 × 10-4 s-1 (t½ of 95 min) which are respectively 50-fold and around 3-fold lower than for the plasmin-streptokinase complex. The acylated complex was stable as evidenced by binding to lysine-Sepharose. However, following an initial short lag phase, the acylated plasmin-STAR complex activated plasminogen at a similar rate as the unblocked complex, whereas the acylated plasmin-streptokinase complex did not activate plasminogen. These findings indicate that STAR, unlike streptokinase, dissociates from its acylated complex with plasmin in the presence of excess plasminogen. In agreement with this hypothesis, the time course of the lysis of a 125I-fibrin labeled plasma clot submerged in citrated human plasma, is similar for acylated plasmin-STAR, unblocked plasmin-STAR and free STAR (50% clot lysis in 2 h requires 12 nM of each agent). The plasma clearances of STAR-related antigen following bolus injection in hamsters were 1.0 to 1.5 ml/min for acylated plasmin-STAR, unblocked plasmin-STAR and free STAR, as a result of short initial half-lives of 2.0 to 2.5 min.The dissociation of the anisoylated plasmin-STAR complex and its consequent rapid clearance suggest that it has no apparent advantages as compared to free STAR for clinical thrombolysis.

The Effect of Heparin vs. Citrate on the Interaction of Platelets with Vascular Graft Materials

1985 ◽  
Vol 54 (04) ◽  
pp. 842-848 ◽  
Author(s):  
Kandice Kottke-Marchant ◽  
James M Anderson ◽  
Albert Rabinovitch ◽  
Richard A Huskey ◽  
Roger Herzig
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Vascular Graft ◽  
Time Course ◽  
Platelet Reactivity ◽  
Polymer Surfaces ◽  
In Vitro Perfusion ◽  
Citrate Anticoagulation ◽  
Platelet Release

SummaryHeparin is known to affect platelet function in vitro, but little is known about the effect of heparin on the interaction of platelets with polymer surfaces in general, and vascular graft materials in particular. For this reason, the effect of heparin vs. citrate anticoagulation on the interaction of platelets with the vascular graft materials expanded polytetrafluoroethylene (ePTFE), Dacron Bionit (DB) and preclotted Dacron Bionit (DB/PC) was studied in a recirculating, in vitro perfusion system. Platelet activation, as shown by a decrease in platelet count, an increase in platelet release and a decrease in platelet aggregation, was observed for all vascular graft materials tested using heparin and was greater for Dacron and preclotted Dacron than for ePTFE. Significant differences between heparin and citrate anticoagulation were seen for platelet release, platelet aggregation and the relative ranking of material platelet-reactivity. However, the trends and time course of platelet activation were similar with both heparin and citrate for the materials tested.

The P-MAPA immunomodulator partially prevents apoptosis induced by Zika virus infection in THP-1 cells

2020 ◽  
Vol 21 ◽  
Author(s):  
Morganna C. Lima ◽  
Elisa A. N. Azevedo ◽  
Clarice N. L. de Morais ◽  
Larissa I. O. de Sousa ◽  
Bruno M. Carvalho ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Virus Infection ◽  
Virus Replication ◽  
Zika Virus ◽  
Mammalian Cells ◽  
Caspase 3 ◽  
Neurological Complications ◽  
Zika Virus Infection

Background: Zika virus is an emerging arbovirus of global importance. ZIKV infection is associated with a range of neurological complications such as the Congenital Zika Syndrome and Guillain Barré Syndrome. Despite the magnitude of recent outbreaks, there is no specific therapy to prevent or to alleviate disease pathology. Objective: To investigate the role of P-MAPA immunomodulator in Zika-infected THP-1 cells. Methods: THP-1 cells were subjected at Zika virus infection (Multiplicity of Infection = 0.5) followed by treatment with P-MAPA for until 96 hours post-infection. After that, the cell death was analyzed by annexin+/ PI+ and caspase 3/ 7+ staining by flow cytometry. In addition, the virus replication and cell proliferation were accessed by RT-qPCR and Ki67 staining, respectively. Results: We demonstrate that P-MAPA in vitro treatment significantly reduces Zika virus-induced cell death and caspase-3/7 activation on THP-1 infected cells, albeit it has no role in virus replication and cell proliferation. Conclusions: Our study reveals that P-MAPA seems to be a satisfactory alternative to inhibits the effects of Zika virus infection in mammalian cells.

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