First Betalain-Producing Bacteria Break the Exclusive Presence of the Pigments in the Plant Kingdom

ABSTRACT The biosynthesis of antioxidant pigments, namely, betalains, was believed to be restricted to Caryophyllales plants. This paper changes this paradigm, and enzyme mining from bacterial hosts promoted the discovery of bacterial cultures producing betalains. The spectrum of possible sources of betalain pigments in nature is broadened by our description of the first betalain-forming bacterium, Gluconacetobacter diazotrophicus. The enzyme-specific step is the extradiol cleavage of the precursor amino acid l-dihydroxyphenylalanine (l-DOPA) to form the structural unit betalamic acid. Molecular and functional work conducted led to the characterization of a novel dioxygenase, a polypeptide of 17.8 kDa with a Km of 1.36 mM, with higher activity and affinity than those of its plant counterparts. Its superior activity allowed the first experimental characterization of the early steps in the biosynthesis of betalains by fully characterizing the presence and time evolution of 2,3- and 4,5-seco-DOPA intermediates. Furthermore, spontaneous chemical reactions are characterized and incorporated into a comprehensive enzymatic-chemical mechanism that yields the final pigments. IMPORTANCE Several studies have demonstrated the health-promoting effects of betalains due to their high antioxidant capacity and their positive effect on the dose-dependent inhibition of cancer cells and their proliferation. To date, betalains were restricted to plants of the order Caryophyllales and some species of fungi, but the present study reveals the first betalain-producing bacterium, as well as the first steps in the formation of pigments. This finding demonstrates that betalain biosynthesis can be expanded to prokaryotes.

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In VitroActivities of Hexaazatrinaphthylenes against Leishmania spp.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00226-15 ◽

2015 ◽

Vol 59 (5) ◽

pp. 2867-2874 ◽

Cited By ~ 13

Author(s):

Atteneri López-Arencibia ◽

Daniel García-Velázquez ◽

Carmen M. Martín-Navarro ◽

Ines Sifaoui ◽

María Reyes-Batlle ◽

...

Keyword(s):

Therapeutic Agents ◽

Content Type ◽

Inhibition Effect ◽

Intracellular Amastigotes ◽

Dependent Inhibition ◽

Leishmania Spp ◽

Dose Dependent Inhibition ◽

Dose Dependent ◽

Potential Use

ABSTRACTThein vitroactivity of a novel group of compounds, hexaazatrinaphthylene derivatives, against two species ofLeishmaniais described in this study. These compounds showed a significant dose-dependent inhibition effect on the proliferation of the parasites, with 50% inhibitory concentrations (IC50s) ranging from 1.23 to 25.05 μM against the promastigote stage and 0.5 to 0.7 μM against intracellular amastigotes. Also, a cytotoxicity assay was carried out to in order to evaluate the possible toxic effects of these compounds. Moreover, different assays were performed to determine the type of cell death induced after incubation with these compounds. The obtained results highlight the potential use of hexaazatrinaphthylene derivatives againstLeishmaniaspecies, and further studies should be undertaken to establish them as novel leishmanicidal therapeutic agents.

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Antileishmanial Mechanism of Diamidines Involves Targeting Kinetoplasts

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01129-16 ◽

2016 ◽

Vol 60 (11) ◽

pp. 6828-6836 ◽

Cited By ~ 12

Author(s):

Gyongseon Yang ◽

Gahee Choi ◽

Joo Hwan No

Keyword(s):

Leishmania Donovani ◽

Nuclear Dna ◽

Binding Properties ◽

Content Type ◽

Topoisomerase Ib ◽

Strong Localization ◽

Dependent Inhibition ◽

Dose Dependent Inhibition ◽

Dna Binding Properties ◽

Dose Dependent

ABSTRACTLeishmaniasis is a disease caused by pathogenicLeishmaniaparasites; current treatments are toxic and expensive, and drug resistance has emerged. While pentamidine, a diamidine-type compound, is one of the treatments, its antileishmanial mechanism of action has not been investigated in depth. Here we tested several diamidines, including pentamidine and its analog DB75, againstLeishmania donovaniand elucidated their antileishmanial mechanisms. We identified three promising new antileishmanial diamidine compounds with 50% effective concentrations (EC50s) of 3.2, 3.4, and 4.5 μM, while pentamidine and DB75 exhibited EC50s of 1.46 and 20 μM, respectively. The most potent antileishmanial inhibitor, compound 1, showed strong DNA binding properties, with a shift in the melting temperature (ΔTm) of 24.2°C, whereas pentamidine had a ΔTmvalue of 2.1°C, and DB75 had a ΔTmvalue of 7.7°C. Additionally, DB75 localized inL. donovanikinetoplast DNA (kDNA) and mitochondria but not in nuclear DNA (nDNA). For 2 new diamidines, strong localization signals were observed in kDNA at 1 μM, and at higher concentrations, the signals also appeared in nuclei. All tested diamidines showed selective and dose-dependent inhibition of kDNA, but not nDNA, replication, likely by inhibitingL. donovanitopoisomerase IB. Overall, these results suggest that diamidine antileishmanial compounds exert activity by accumulating toward and blocking replication of parasite kDNA.

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Structure Confirmation and Evaluation of a Nonsteroidal Inhibitor of 17β-Hydroxysteroid Dehydrogenase Type 10

Magnetochemistry ◽

10.3390/magnetochemistry4030032 ◽

2018 ◽

Vol 4 (3) ◽

pp. 32 ◽

Cited By ~ 4

Author(s):

Sophie Boutin ◽

Donald Poirier

Keyword(s):

Hydroxysteroid Dehydrogenase ◽

One Pot ◽

Intact Cells ◽

Hek 293 ◽

Biological Assays ◽

13C Nuclear Magnetic Resonance ◽

Dependent Inhibition ◽

Dose Dependent Inhibition ◽

Dose Dependent

17β-Hydroxysteroid dehydrogenase type 10 (17β-HSD10) is a steroidogenesis enzyme known for its potential role in Alzheimer’s disease. For comparison purposes between steroidal and nonsteroidal 17β-HSD10 inhibitors 1 and 2, respectively, we attempted the chemical synthesis of benzothiazole phosphonate derivative 2. Instead of a one-pot synthesis, we report a two-step synthesis with characterization of both imine intermediate 5 and final compound 2. Furthermore, complete assignation of 1H and 13C nuclear magnetic resonance (NMR) signals of 2 is provided, as we observed a divergence of NMR data with those published previously. Finally, biological assays showed that 1 and 2 inhibited the oxidation of estradiol (E2) into estrone (E1) by the 17β-HSD10 recombinant protein. However, in human embryonic kidney (HEK)-293 intact cells transfected with 17β-HSD10, only the steroidal inhibitor 1 induced a dose-dependent inhibition of E2 to E1 transformation.

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Inhibition by dipyridamole of cerebral vasospasm induced in vitro by whole blood

Journal of Neurosurgery ◽

10.3171/jns.1983.58.3.0352 ◽

1983 ◽

Vol 58 (3) ◽

pp. 352-355 ◽

Cited By ~ 7

Author(s):

Martin Linder

Keyword(s):

Cerebral Artery ◽

Whole Blood ◽

Prostaglandin Synthesis ◽

Cerebral Vessel ◽

Content Type ◽

Arterial Blood ◽

Dependent Inhibition ◽

Dose Dependent Inhibition ◽

Dose Dependent

✓ This study evaluates the effect of dipyridamole, an inhibitor of platelet aggregation, on cerebral artery contraction induced in vitro by the addition of whole blood. Whole fresh arterial blood added to isolated rabbit basilar artery bathed in a physiological buffer produces a sustained contraction in vessels observed for 60 minutes. Significant dose-dependent inhibition of contraction was observed when dipyridamole was added to the vessel bath. This effect was not influenced by preincubating cerebral vessels with aspirin, an inhibitor of prostaglandin synthesis. It is suggested that inhibition of whole blood-induced cerebral artery contraction by dipyridamole does not result from potentiation of cerebral vessel prostaglandin pathways, but possibly from a direct effect on platelets.

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Differences between antigenic determinants of pig and cat zona pellucida proteins

Reproduction ◽

10.1530/reprod/119.1.15 ◽

2000 ◽

pp. 15-23 ◽

Cited By ~ 15

Author(s):

K Jewgenow ◽

M Rohleder ◽

I Wegner

Keyword(s):

In Vitro Fertilization ◽

Zona Pellucida ◽

Antigenic Determinants ◽

Vitro Fertilization ◽

Contraceptive Vaccine ◽

Sperm Binding ◽

Dependent Inhibition ◽

Dose Dependent Inhibition ◽

Dose Dependent

Despite many efforts, the control of reproduction in feral cat populations is still a problem in urban regions around the world. Immunocontraception is a promising approach; thus the present study examined the suitability of the widely used pig zona pellucida proteins (pZP) for contraception in feral domestic cats. Purified zona pellucida proteins obtained from pig and cat ovaries were used to produce highly specific antisera in rabbits. Antibodies against pZP raised in rabbits or lions were not effective inhibitors of either in vitro sperm binding (cat spermatozoa to cat oocytes) or in vitro fertilization in cats, whereas antibodies against feline zona pellucida proteins (fZP) raised in rabbits showed a dose-dependent inhibition of in vitro fertilization. Immunoelectrophoresis, ELISA and immunohistology of ovaries confirmed these results, showing crossreactivity of anti-fZP sera to fZP and to a lesser extent to pZP, but no interaction of anti-pZP sera with fZP. It is concluded that cat and pig zonae pellucidae express a very small number of shared antigenic determinants, making the use of pZP vaccine in cats questionable. A contraceptive vaccine based on feline zona pellucida determinants will be a better choice for the control of reproduction in feral cats if immunogenity can be achieved.

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Antioxidant effects and in vitro cytotoxicity on human cancer cell lines of flavonoid-rich Flamboyant (Delonix regia (Bojer) Raf.) flower extract

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666201029154746 ◽

2020 ◽

Vol 21 ◽

Author(s):

Putthiporn Khongkaew ◽

Phanphen Wattanaarsakit ◽

Konstantinos I. Papadopoulos ◽

Watcharaphong Chaemsawang

Keyword(s):

Cell Line ◽

Cell Lines ◽

Cancer Cell ◽

Leukemia Cell ◽

Leukemia Cell Line ◽

Flower Extract ◽

Dependent Inhibition ◽

Dose Dependent Inhibition ◽

Murine Leukemia Cell ◽

Dose Dependent

Background: Cancer is a noncommunicable disease with increasing incidence and mortality rates both worldwide and in Thailand. Its apparent lack of effective treatments is posing challenging public health issues. Introduction: Encouraging research results indicating probable anti-cancer properties of the Delonix regia flower extract (DRE) have prompted us to evaluate the feasibility of developing a type of product for future cancer prevention or treatment. Methods and Results: In the present report, using High Performance Liquid Chromatography (HPLC), we demonstrate in the DRE, the presence of high concentrations of three identifiable flavonoids, namely rutin 4.15±0.30 % w/w, isoquercitrin 3.04±0.02 %w/w, and myricetin 2.61±0.01 % w/w respectively while the IC50 of DPPH and ABTS assay antioxidation activity was 66.88±6.30 µg/ml and 53.65±7.24 µg/ml respectively. Discussion: Our cancer cell line studies using the MTT assay demonstrated DREs potent and dose dependent inhibition of murine leukemia cell line (P-388: 35.28±4.07% of cell viability remaining), as well as of human breast adenocarcinoma (MCF-7), human cervical carcinoma (HeLa), human oral cavity carcinoma (KB), and human colon carcinoma (HT-29) cell lines in that order of magnitude. Conclusion: Three identifiable flavonoids (rutin, isoquercitrin and myricetin) with high antioxidation activity and potent and dose dependent inhibition of murine leukemia cell line and five other cancer cell lines were documented in the DRE. The extract’s lack of cytotoxicity in 3 normal cell lines is a rare advantage not usually seen in current antineoplastic agents. Yet another challenge of the DRE was its low dissolution rate and long-term storage stability, issues to be resolved before a future product can be formulated.

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Investigation on the antibacterial activity of electronic cigarette liquids (ECLs): a proof of concept study

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666200903121624 ◽

2020 ◽

Vol 21 ◽

Cited By ~ 1

Author(s):

Virginia Fuochi ◽

Massimo Caruso ◽

Rosalia Emma ◽

Aldo Stivala ◽

Riccardo Polosa ◽

...

Keyword(s):

Antibacterial Activity ◽

Bacterial Species ◽

A549 Cells ◽

Bactericidal Effect ◽

Minimal Bactericidal Concentration ◽

Viability Assay ◽

Dependent Inhibition ◽

Dose Dependent Inhibition ◽

Dose Dependent

Background: The key ingredients of e-cigarettes liquid are commonly propane-1,2-diol (also called propylene glycol) and propane-1,2,3-triol (vegetal glycerol) and their antimicrobial effects are already established. The nicotine and flavors which are often present in e-liquids can interfere with the growth of some microorganisms. Objective: The effect of the combining these elements in e-liquids is unknown. The aim of the study was to investigate the possible effects of these liquids on bacterial growth in the presence or absence of nicotine and flavors. Methods: Susceptibilities of pathogenic strains (Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis and Sarcina lutea) were studied by means of a multidisciplinary approach. Cell viability and antioxidant assays were also evaluated. Results: All e-liquids investigated showed antibacterial activity against at least one pathogenic strain. A higher activity was correlated to the presence of flavors and nicotine. Discussion: In most cases the value of minimal bactericidal concentration is equal to the value of minimal inhibitory concentration showing that these substances have a bactericidal effect. This effect was observed in concentrations up to 6.25% v/v. Antioxidant activity was also correlated to presence of flavors. Over time, the viability assay in human epithelial lung A549 cells showed a dose-dependent inhibition of cell growth. Conclusion: Our results have shown that flavors considerably enhance the antibacterial activity of propane-1,2-diol and propane-1,2,3-triol. This study provides important evidence that should be taken into consideration in further investigative approaches, to clarify the different sensitivity of the various bacterial species to e-liquids, including the respiratory microbiota, to highlight the possible role of flavors and nicotine.

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μ-Opiate Receptors in Neuronal Primary Cultures from Cerebral Cortex

Alternatives to Laboratory Animals ◽

10.1177/026119299001700308 ◽

1990 ◽

Vol 17 (3) ◽

pp. 177-181

Author(s):

Peter S. Eriksson ◽

Elisabeth Hansson ◽

Lars Rönnbäck

Keyword(s):

Cerebral Cortex ◽

Primary Cultures ◽

Opiate Receptors ◽

Neuronal Cultures ◽

Camp Accumulation ◽

Dependent Inhibition ◽

Dose Dependent Inhibition ◽

Neuronal Primary Cultures ◽

Dose Dependent ◽

Μ Receptor

The presence of μ-opioid receptors was demonstrated as effects of receptor stimulation on PGE1-induced cAMP accumulation in neuronal-enriched primary cultures from rat cerebral cortex. Morphine was used as a μ-receptor agonist. There was a dose-dependent inhibition of the PGE1-stimulated cAMP accumulation by morphine, blocked by the μ-receptor antagonist naloxone. These findings suggest that these neuronal cultures express μ-receptors, possibly connected to adenylate cyclase via an inhibitory Gi-protein. The probable use of functional μ-receptors in neurotoxicological tests is discussed.

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