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Antimicrobial Agents and Chemotherapy Apr 2015Naegleria fowleri is a pathogenic free-living amoeba (FLA) that causes an acute fatal disease known as primary amoebic meningoencephalitis (PAM). The major problem for...
Naegleria fowleri is a pathogenic free-living amoeba (FLA) that causes an acute fatal disease known as primary amoebic meningoencephalitis (PAM). The major problem for infections with any pathogenic FLA is a lack of effective therapeutics, since PAM has a case mortality rate approaching 99%. Clearly, new drugs that are potent and have rapid onset of action are needed to enhance the treatment regimens for PAM. Diamidines have demonstrated potency against multiple pathogens, including FLA, and are known to cross the blood-brain barrier to cure other protozoan diseases of the central nervous system. Therefore, amidino derivatives serve as an important chemotype for discovery of new drugs. In this study, we validated two new in vitro assays suitable for medium- or high-throughput drug discovery and used these for N. fowleri. We next screened over 150 amidino derivatives of multiple structural classes and identified two hit series with nM potency that are suitable for further lead optimization as new drugs for this neglected disease. These include both mono- and diamidino derivatives, with the most potent compound (DB173) having a 50% inhibitory concentration (IC50) of 177 nM. Similarly, we identified 10 additional analogues with IC50s of <1 μM, with many of these having reasonable selectivity indices. The most potent hits were >500 times more potent than pentamidine. In summary, the mono- and diamidino derivatives offer potential for lead optimization to develop new drugs to treat central nervous system infections with N. fowleri.
Topics: Amebiasis; Animals; Antiprotozoal Agents; Benzimidazoles; Cell Line; Cell Survival; Central Nervous System Protozoal Infections; High-Throughput Screening Assays; Mice; Naegleria fowleri; Structure-Activity Relationship
PubMed: 25605363
DOI: 10.1128/AAC.05122-14 -
Rejuvenation Research Oct 2015Our previous study suggests that ginger root extract can reverse behavioral dysfunction and prevent Alzheimer's disease (AD)-like symptoms induced by the amyloid-β...
Our previous study suggests that ginger root extract can reverse behavioral dysfunction and prevent Alzheimer's disease (AD)-like symptoms induced by the amyloid-β protein (Aβ) in a rat model. 6-Gingerol is the major gingerol in ginger rhizomes, but its effect on the treatment of AD remains unclear. In this study, we aimed to determine if 6-gingerol had a protective effect on Aβ1-42-induced damage and apoptotic death in rat pheochromocytoma cells (PC12 cells) and to investigate the underlying mechanisms by which 6-gingerol may exert its neuroprotective effects. Our results indicated that pre-treatment with 6-gingerol significantly increased cell viability and reduced cell apoptosis in Aβ1-42-treated cells. Moreover, 6-gingerol pretreatment markedly reduced the level of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), the production of nitric oxide (NO), and the leakage of lactate dehydrogenase (LDH) and increased superoxide dismutase (SOD) activity compared with the Aβ1-42 treatment group. In addition, 6-gingerol pretreatment also significantly enhanced the protein levels of phosphorylated Akt (p-Akt) and glycogen synthase kinase-3β (p-GSK-3β). Overall, these results indicate that 6-gingerol exhibited protective effects on apoptosis induced by Aβ1-42 in cultured PC12 cells by reducing oxidative stress and inflammatory responses, suppressing the activation of GSK-3β and enhancing the activation of Akt, thereby exerting neuroprotective effects. Therefore, 6-gingerol may be useful in the prevention and/or treatment of AD.
Topics: Amyloid beta-Peptides; Animals; Apoptosis; Bisbenzimidazole; Catechols; Cell Survival; Culture Media; Enzyme Activation; Fatty Alcohols; Flow Cytometry; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Intracellular Space; L-Lactate Dehydrogenase; Malondialdehyde; Nitric Oxide; PC12 Cells; Peptide Fragments; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Reactive Oxygen Species; Staining and Labeling; Superoxide Dismutase
PubMed: 25811848
DOI: 10.1089/rej.2014.1657 -
Polymers May 2023Polyimide (PI) with ultra-high thermal resistance and stability is essential for application as a flexible substrate in electronic devices. Here, the Upilex-type...
Polyimide (PI) with ultra-high thermal resistance and stability is essential for application as a flexible substrate in electronic devices. Here, the Upilex-type polyimides, which contained flexibly "twisted" 4,4'-oxydianiline (ODA), have achieved various performance improvements via copolymerization with a diamine containing benzimidazole structure. With the rigid benzimidazole-based diamine bearing conjugated heterocyclic moieties and hydrogen bond donors fused into the PI backbone, the benzimidazole-containing PI showed outstanding thermal, mechanical, and dielectric performance. Specifically, the PI containing 50% bis-benzimidazole diamine achieved a 5% decomposition temperature at 554 °C, an excellent high glass transition temperature of 448 °C, and a coefficient of thermal expansion lowered to 16.1 ppm/K. Meanwhile, the tensile strength and modulus of the PI films containing 50% mono-benzimidazole diamine increased to 148.6 MPa and 4.1 GPa, respectively. Due to the synergistic effect of rigid benzimidazole and hinged, flexible ODA, all PI films exhibited an elongation at break above 4.3%. The electrical insulation of the PI films was also improved with a dielectric constant lowered to 1.29. In summary, with appropriate mixing of rigid and flexible moieties in the PI backbone, all the PI films showed superior thermal stability, excellent flexibility, and acceptable electrical insulation.
PubMed: 37242916
DOI: 10.3390/polym15102343 -
Proceedings of the National Academy of... Dec 1991A hybrid cell line was produced by the fusion of an EC3/7 mouse cell with a Chinese hamster ovary cell. The EC3/7 cell carries a dicentric chromosome with a functional...
A hybrid cell line was produced by the fusion of an EC3/7 mouse cell with a Chinese hamster ovary cell. The EC3/7 cell carries a dicentric chromosome with a functional marker centromere. This marker centromere contains human, lambda, and bacterial vector DNA sequences and a dominant selectable gene (aminoglycoside 3'-phosphotransferase type II; neo). In the hybrid, the marker centromere separated from the dicentric chromosome and formed a full-sized chromosome (lambda neo). The newly formed chromosome is stable, even under nonselective culture conditions. This functional chromosome, which is the result of an amplification process, is composed of seven large, different-sized amplicons. Each amplicon contains multiple copies of human, lambda, neo, and mouse telomeric DNA sequences. Individual amplicons are separated from each other by mouse major satellite DNA sequences. The marker centromere was localized to a terminal amplicon by anticentromere immunostaining. The number of amplicons in the newly formed chromosome is remarkably consistent. This finding suggests that the length of the newly formed chromosome is highly constrained.
Topics: Animals; Bisbenzimidazole; CHO Cells; Cell Fusion; Cell Line; Centromere; Chromosomes; Cricetinae; DNA Probes; Fluorescent Antibody Technique; Hybrid Cells; Mice; Telomere
PubMed: 1722315
DOI: 10.1073/pnas.88.24.11042 -
Biophysical Journal Nov 2010PicoGreen is a fluorescent probe that binds dsDNA and forms a highly luminescent complex when compared to the free dye in solution. This unique probe is widely used in...
PicoGreen is a fluorescent probe that binds dsDNA and forms a highly luminescent complex when compared to the free dye in solution. This unique probe is widely used in DNA quantitation assays but has limited application in biophysical analysis of DNA and DNA-protein systems due to limited knowledge pertaining to its physical properties and characteristics of DNA binding. Here we have investigated PicoGreen binding to DNA to reveal the origin and mode of PicoGreen/DNA interactions, in particular the role of electrostatic and nonelectrostatic interactions in formation of the complex, as well as demonstrating minor groove binding specificity. Analysis of the fluorescence properties of free PicoGreen, the diffusion properties of PG/DNA complexes, and the excited-state lifetime changes upon DNA binding and change in solvent polarity, as well as the viscosity, reveal that quenching of PicoGreen in the free state results from its intramolecular dynamic fluctuations. On binding to DNA, intercalation and electrostatic interactions immobilize the dye molecule, resulting in a >1000-fold enhancement in its fluorescence. Based on the results of this study, a model of PicoGreen/DNA complex formation is proposed.
Topics: Binding Sites; Biophysical Phenomena; Bisbenzimidazole; DNA; Fluorescent Dyes; Intercalating Agents; Macromolecular Substances; Models, Molecular; Molecular Dynamics Simulation; Organic Chemicals; Spectrometry, Fluorescence; Static Electricity
PubMed: 21044599
DOI: 10.1016/j.bpj.2010.09.012 -
Progress in Biophysics and Molecular... 1986
Review
Nonintercalating DNA-binding ligands: specificity of the interaction and their use as tools in biophysical, biochemical and biological investigations of the genetic material.
Topics: Aminoglycosides; Animals; Anthramycin; Antibiotics, Antineoplastic; Base Sequence; Binding Sites; Bisbenzimidazole; Cattle; Centrifugation, Density Gradient; Chemical Phenomena; Chemistry, Physical; Chromosomes; Circular Dichroism; DNA; DNA, Superhelical; Diminazene; Distamycins; Drug Interactions; Duocarmycins; Indoles; Leucomycins; Ligands; Magnetic Resonance Spectroscopy; Mathematics; Models, Molecular; Netropsin; Plicamycin; Protein Conformation; Pyridinium Compounds; RNA; Spectrophotometry, Ultraviolet; Staining and Labeling; Thermodynamics
PubMed: 2422697
DOI: 10.1016/0079-6107(86)90005-2 -
RSC Advances Dec 2018A novel perylene bisbenzimidazole comprising both donor and acceptor functional groups was designed, synthesized, and characterized. This structure exhibits potentially...
A novel perylene bisbenzimidazole comprising both donor and acceptor functional groups was designed, synthesized, and characterized. This structure exhibits potentially useful physical properties, including a nonlinear dielectric response to an increasing electric field. This material can be used in energy storage devices as the dielectric part of a capacitor. Energy storage devices based on film capacitors are targeting applications in a wide range of industrial, residential and transportation systems.
PubMed: 35521607
DOI: 10.1039/c8ra08873j -
Cytometry. Part a : the Journal of the... Nov 2011Flow cytometry is a potentially efficient approach for the quantification of parasitemias in experimental malaria infections and drug susceptibility assays using rodent...
Flow cytometry is a potentially efficient approach for the quantification of parasitemias in experimental malaria infections and drug susceptibility assays using rodent malaria models such as Plasmodium berghei. In this study, we used two red DNA-binding fluorochromes, rhodamine 800 (R800) and LD700, to measure parasitemia levels in whole blood samples from mice infected with P. berghei. Blood samples were treated with RNAse A to eliminate RNA-derived signals. Propidium iodide, which stains both DNA and RNA, was used as a positive control. The parasitemia levels determined by R800 and LD700 were comparable to those calculated by microscopic analysis of blood smears and flow cytometry using Hoechst 33258. RNAse treatment did not affect these measurements. We also used R800 or LD700 to quantify parasitemias in mice infected with a GFP-expressing P. berghei line to correlate the parasitemia levels determined by DNA staining versus parasite numbers using GFP fluorescence as a surrogate measurement. A positive correlation was found between levels determined by flow cytometry using these dyes and those measured by GFP expression. Similar results were obtained when parasitemias determined by flow cytometry were compared to those determined by conventional microscopy. The limit of detection of infected red blood cells using R800 or LD700 staining was 0.1% and 0.15%, respectively. This study demonstrates that red laser-based flow cytometry using R800 or LD700 can be used for effective quantification of parasitemia levels in Plasmodium infected red blood cells. Furthermore, this method has the advantage that it does not require RNAse pretreatment and allows for a greater amount of cells to be analyzed for parasite burden than otherwise measured by conventional microscopy. © 2011 International Society for Advancement of Cytometry.
Topics: Animals; Bisbenzimidazole; Erythrocytes; Female; Flow Cytometry; Fluorescence; Fluorescent Dyes; Green Fluorescent Proteins; Limit of Detection; Malaria; Mice; Mice, Transgenic; Parasitemia; Plasmodium berghei; Propidium; Rhodamines; Ribonucleases; Staining and Labeling
PubMed: 22015734
DOI: 10.1002/cyto.a.21119 -
Zeitschrift Fur Naturforschung. C,... 1991The comparative anthelmintic activity of a possible prodrug, 2,2'-dicarbomethoxyamino-5,5'-dibenzimidazolyl methanol (2) with its parent compound... (Comparative Study)
Comparative Study
The comparative anthelmintic activity of a possible prodrug, 2,2'-dicarbomethoxyamino-5,5'-dibenzimidazolyl methanol (2) with its parent compound 2,2'-dicarbomethoxyamino-5,5'-dibenzimidazolyl ketone (1) and the reference drug mebendazole (3a) is reported. At a dose of 25 mg/kg, compound 2 was 100% effective against Ancylostoma ceylanicum in hamsters. Compound 2 also exhibited a similar order of activity against Syphacia obvelata, Hymenolepis nana and H. diminuta at a dose of 100 mg/kg. The drug exhibited lethal effects against metamorphic forms of A. ceylanicum at a dose of 100 mg/kg. However the trichostrongylids, Nippostrongylus brasiliensis remained unaffected up to a dose of 250 mg/kg of 2. Both 1 and 3a exhibited inferior activity than 2 except against adult A. ceylanicum. The activity of 1 and 2 has been explained on the basis of their ability to resist systemic hydrolysis resulting in higher concentration of the active drug in biophase.
Topics: Animals; Anthelmintics; Cricetinae; Helminthiasis; Helminths; Mebendazole; Mice; Prodrugs; Rats
PubMed: 1776998
DOI: 10.1515/znc-1991-7-826 -
Genetics and Molecular Research : GMR Jan 2015Croton membranaceus aqueous root extract (CMARE) is among the widely used phytotherapeutics in Ghana for the management of benign prostatic hyperplasia (BPH) and...
Croton membranaceus aqueous root extract (CMARE) is among the widely used phytotherapeutics in Ghana for the management of benign prostatic hyperplasia (BPH) and prostate cancer. However, the mechanism of action of CMARE remains to be elucidated. This study aimed to establish whether apoptosis is involved in the antiproliferative effect of CMARE on human BPH-1 cells. We determined the effect of treatment with 0, 1, 3, and 5 mg/mL CMARE for 24, 48, and 72 h on the viability and morphology of BPH-1 cells using the MMT assay and phase-contrast microscopy, respectively. We examined the apoptosis-inducing effects of CMARE after 48 h at the cellular level using Hoescht 33258 and JC-1 dye staining and flow cytometry analysis. We performed reverse transcription polymerase chain reaction and Western blotting to confirm the apoptotic effects of CMARE at the molecular level. CMARE induced a significant dose-dependent inhibition in the proliferation of BPH-1 cells (P < 0.05) and an alteration in their morphology and a reduction their density. Furthermore, CMARE induced dose-dependent staining of the nuclear chromatin, significant DNA fragmentation with G₀/G₁ sub-diploid cells (P < 0.01), and loss of the mitochondrial membrane potential in the treated cells compared to the controls after 48 h (P < 0.01). Additionally, while CMARE induced a significant upregulation of the mRNA and protein levels of Bax, those of Bcl2 did not change significantly. Therefore, induction of mitochondria-dependent apoptosis of BPH-1 cells may be a possible mechanism of action of CMARE.
Topics: Apoptosis; Bisbenzimidazole; Cell Cycle; Cell Line, Tumor; Cell Nucleus Shape; Cell Proliferation; Cell Survival; Croton; Flow Cytometry; Humans; Male; Membrane Potential, Mitochondrial; Mitochondria; Plant Extracts; Plant Roots; Prostatic Hyperplasia; Proto-Oncogene Proteins c-bcl-2
PubMed: 25729946
DOI: 10.4238/2015.January.15.18