Search results for "Propidium"
showing 10 items of 73 documents
Characterization of the interaction of the antifungal and cytotoxic cyclic glycolipopeptide hassallidin with sterol-containing lipid membranes.
2019
Hassallidins are cyclic glycolipopeptides produced by cyanobacteria and other prokaryotes. The hassallidin structure consists of a peptide ring of eight amino acids where a fatty acid chain, additional amino acids, and sugar moieties are attached. Hassallidins show antifungal activity against several opportunistic human pathogenic fungi, but does not harbor antibacterial effects. However, they have not been studied on mammalian cells, and the mechanism of action is unknown. We purified hassallidin D from cultured cyanobacterium Anabaena sp. UHCC 0258 and characterized its effect on mammalian and fungal cells. Ultrastructural analysis showed that hassallidin D disrupts cell membranes, causin…
Interfering with Arginine Metabolism As a New Treatment Strategy for Multiple Myeloma
2015
Abstract Introduction Starvation of tumor cells from the amino acid arginine has recently gained particular interest because of the downregulation of the rate-limiting enzyme argininosuccinate synthethase 1 (ASS1) in various cancer entities. ASS1-deficient cells cannot resynthesize arginine from citrulline and are therefore considered arginine auxotrophic. The arginine depleting enzyme arginine deiminase (ADI-PEG20, Polaris Pharmaceuticals) is currently tested in phase I-III clinical trials for different arginine auxotrophic cancers. The natural arginine analogue canavanine can compete with arginine for arginyl-tRNA-binding sites and consequently be incorporated into nascent proteins instea…
Application of propidium monoazide-qPCR to evaluate the ultrasonic inactivation of Escherichia coli O157:H7 in fresh-cut vegetable wash water.
2012
The efficacy of sanitizing technologies in produce or in vegetable wash water is generally evaluated by plate count in selective media. This procedure is time consuming and can lead to misinterpretations because environmental conditions and sanitizing processes may affect bacterial growth or culturable capability. Thus, the aim of this study was to determine the applicability of a propidium monoazide real-time PCR (PMA-qPCR) method to monitor the inactivation by ultrasound treatment of foodborne bacteria in fresh-cut vegetable wash water. To this aim, lettuce wash water was artificially inoculated with Escherichia coli O157:H7 (10⁶ CFU/mL) and treated by means of a continuous ultrasonic irr…
Application of viability PCR to discriminate the infectivity of hepatitis A virus in food samples.
2015
Abstract Transmitted through the fecal–oral route, the hepatitis A virus (HAV) is acquired primarily through close personal contact and foodborne transmission. HAV detection in food is mainly carried out by quantitative RT-PCR (RT-qPCR). The discrimination of infectious and inactivated viruses remains a key obstacle when using RT-qPCR to quantify enteric viruses in food samples. Initially, viability dyes, propidium monoazide (PMA) and ethidium monoazide (EMA), were evaluated for the detection and quantification of infectious HAV in lettuce wash water. Results showed that PMA combined with 0.5% Triton X-100 (Triton) was the best pretreatment to assess HAV infectivity and completely eliminate…
Application of propidium monoazide quantitative PCR for selective detection of live Escherichia coli O157:H7 in vegetables after inactivation by esse…
2012
The use of propidium monoazide (PMA) is enjoying increased popularity among researchers in different fields of microbiology. Its use in combination with real-time PCR (qPCR) represents one of the most successful approaches to detect viable cells. PMA-qPCR has successfully been used to evaluate the efficacy of various disinfection technologies in different microorganisms. Initially, in this study the effect of four essential oils (EOs), cumin, clove, oregano and cinnamon, was evaluated on suspensions of the enterohemorrhagic Escherichia coli O157:H7 by PMA-qPCR, LIVE/DEAD BacLight flow cytometry analysis (LIVE/DEAD-FCM), and plate count. E. coli O157:H7 cells treated with EOs at killing conc…
Cell Harvesting Methods Affect Cellular Integrity of Adherent Cells During Apoptosis Detection.
2018
Background/aim Annexin V and propidium iodide (PI) dual staining is commonly applied in bioscience as a method to detect apoptosis. However, excessive handling of adherent cells may interfere with the integrity of plasma membrane and hence impede the accuracy of this method. Here, we exploited PI uptake as an indicator of cell integrity and investigated how cell harvesting methods and solutions involved in common apoptosis detection techniques affected measurement results. Materials and methods Different cell harvesting techniques, staining with PI and flow cytometry were performed. Results Non-fixed scrapped cells revealed significantly higher fractions of PI-positive staining compared to …
Analysis of Antiproliferative and Chemosensitizing Effects of Sunitinib on Human Esophagogastric Cancer Cells: Synergistic Interaction With Vandetani…
2009
The receptor tyrosine kinases (RTKs), epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor 1-3 (VEGFR1-3), are frequently expressed in gastric cancer and are putative therapeutic targets in this disease. We have investigated the anti-proliferative and chemosensitizing properties of the multitargeted small-molecule RTK inhibitors sunitinib and vandetanib in a panel of 4 human gastric and esophageal cancer cell lines. In the 1st instance, the expression of potential targets of these small-molecule inhibitors was examined by reverse transcriptase-polymerase chain reaction, western blotting, and flow cytometry. EGFR mRNA and protein was detected in all cases, …
Parthenolide generates reactive oxygen species and autophagy in MDA-MB231 cells. A soluble parthenolide analogue inhibits tumour growth and metastasi…
2013
Triple-negative breast cancers (TNBCs) are clinically aggressive forms associated with a poor prognosis. We evaluated the cytotoxic effect exerted on triple-negative MDA-MB231 breast cancer cells both by parthenolide and its soluble analogue dimethylamino parthenolide (DMAPT) and explored the underlying molecular mechanism. The drugs induced a dose- and time-dependent decrement in cell viability, which was not prevented by the caspase inhibitor z-VAD-fmk. In particular in the first hours of treatment (1–3 h), parthenolide and DMAPT strongly stimulated reactive oxygen species (ROS) generation. The drugs induced production of superoxide anion by activating NADPH oxidase. ROS generation caused…
Aspidin PB, a phloroglucinol derivative, induces apoptosis in human hepatocarcinoma HepG2 cells by modulating PI3K/Akt/GSK3β pathway.
2012
Aspidin PB, a phloroglucinol derivative isolated from Dryopteris fragrans (L.) Schott, has been previously reported to exert high biological activities. In the present study, we analyzed the apoptotic mechanisms of aspidin PB on human hepatoma cell line, HepG2. Initially, aspidin PB was shown to inhibit the growth of HepG2 cells in a time and dose-dependent manner. After treatment with aspidin PB for 72 h, 48 h and 24 h using MTT assay, the IC(50) values were 10.59 μM, 20.86 μM and 46.59 μM, respectively. Aspidin PB was capable to induce apoptosis, as measured by mitochondrial membrane potential (ΔΨm), acridine orange (AO) staining and propidium iodide (PI)/annexin V-FITC double staining. T…
Cryopreservation of Escherichia coli K12TG1: Protection from the damaging effects of supercooling by freezing
2015
Injuries in living cells caused by water freezing during a freeze-thaw process have been extensively reported. In particular, intracellular water freezing has long been incriminated in cell death caused by a high cooling rate, but this supposition could not always be demonstrated. This work aims to discriminate the role of water freezing, dehydration and cold-induced injuries in cellular damage occuring during cryopreservation. For this purpose, Escherichia coli K12TG1 suspensions were maintained in a supercooled or frozen state at -20°C for times ranging from 10 min to 5 h. The supercooled state was maintained for a long period at -20°C by applying a non-injurious isostatic pressure (P<40 …