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1.
Chemosphere ; 241: 125061, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31877619

RESUMO

Cyanobacteria routinely release potentially harmful bioactive compounds into the aquatic environment. Several recent studies suggested a potential link between the teratogenicity of effects caused by cyanobacteria and production of retinoids. To investigate this relationship, we analysed the teratogenicity of field-collected cyanobacterial bloom samples by means of an in vivo zebrafish embryo test, an in vitro reporter gene bioassay and by the chemical analysis of retinoids. Extracts of biomass from cyanobacterial blooms with the dominance of Microcystis aeruginosa and Aphanizomenon klebahnii were collected from water bodies in the Czech Republic and showed significant retinoid-like activity in vitro, as well as high degrees of teratogenicity in vivo. Chemical analysis was then used to identify a set of retinoids in ng per gram of dry weight concentration range. Subsequent fractionation and bioassay-based characterization identified two fractions with significant in vitro retinoid-like activity. Moreover, in most of the retinoids eluted from these fractions, teratogenicity with malformations typical for retinoid signalling disruption was observed in zebrafish embryos after exposure to the total extracts and these in vitro effective fractions. The zebrafish embryo test proved to be a sensitive toxicity indicator of the biomass extracts, as the teratogenic effects occurred at even lower concentrations than those expected from the activity detected in vitro. In fact, teratogenicity with retinoid-like activity was detected at concentrations that are commonly found in biomasses and even in bulk water surrounding cyanobacterial blooms. Overall, these results provide evidence of a link between retinoid-like activity, teratogenicity and the retinoids produced by cyanobacterial water blooms in the surrounding environment.


Assuntos
Cianobactérias/patogenicidade , Embrião não Mamífero/efeitos dos fármacos , Retinoides/toxicidade , Teratogênios/toxicidade , Peixe-Zebra/embriologia , Animais , Aphanizomenon/patogenicidade , Cianobactérias/química , República Tcheca , Genes Reporter , Microcystis/patogenicidade , Retinoides/biossíntese , Peixe-Zebra/genética
2.
Chemosphere ; 236: 124395, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31545198

RESUMO

The detection of oxidative stress caused by emerging pollutants in aquatic systems is essential to carry out toxicological analysis since they can bring us information about the mechanisms of toxic action of the pollutants, which might be useful to address this contamination. To achieve this goal, two self-bioluminescent strains that respond to oxidative stress based on the filamentous cyanobacterium Nostoc sp. PCC7120, which has a high ecological relevance in aquatic continental systems, have been constructed. Nostoc sp. PCC7120 pBG2172 harbours the promoter region of the 2-cys-prx gene (P2-cys-prx), encoding a cytoplasmic peroxiredoxin, fused to luxCDABE genes of the bacterium Photorhabdus luminescens. Nostoc sp. PCC7120 pBG2173 harbours the promoter region of the KatA gene (PkatA), a cytoplasmic catalase, also fused to luxCDABE genes. Both strains have been characterized by exposing them to H2O2: Nostoc sp. PCC7120 pBG2172 responded while Nostoc sp. PCC7120 pBG2173 did not respond to this pollutant. In order to know their specificity, they were exposed to methyl viologen (MV), an herbicide that produces superoxide anion (O2-) and a bioluminescence response was observed in both strains. Besides, the utility of these strains for the detection of H2O2 and MV in natural water samples, both pristine and wastewater samples has been tested by spiking experiments. Finally, the possible application of these strains for the detection of the emerging pollutant triclosan has also been tested showing to be suitable bioreporters to study oxidative stress in aquatic environments.


Assuntos
Catalase/química , Cianobactérias/química , Hidrobiologia/normas , Peroxirredoxinas/química , Estresse Oxidativo
3.
Chem Commun (Camb) ; 55(76): 11410-11413, 2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31482869

RESUMO

Graphene-based composite materials are versatile but not easily procurable. Cyanobacterial cells, an outgrowth of eutrophic freshwater lake, were simultaneously employed as a template for the growth of ZnO nanoparticles and as a biomass carbon source for graphene sheets, resulting in chlorophyll-containing graphene-wrapped ZnO nanospheres.


Assuntos
Cianobactérias/química , Cianobactérias/citologia , Grafite/química , Nanosferas/química , Óxido de Zinco/química , Clorofila/química
4.
Biochim Biophys Acta Bioenerg ; 1860(10): 148059, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31394097

RESUMO

Based on characterization by X-ray absorption spectroscopy, it has been proposed that the Mn4CaO5 cluster in the crystal structure of the water-oxidizing enzyme, photosystem II (PSII), may represent an over-reduced form arising from reduction by the X-ray beam. Using a quantum mechanical/molecular mechanical approach, and assuming that all of the µ-oxo bridges are deprotonated in S1, we analyzed the reduction process of the Mn4CaO5 cluster. In the crystal structure, the O atom (O5), which is linked with three Mn atoms and one Ca atom, has no H-bond. When reduced to S-2, unexpectedly, a water molecule at Ca2+ (W3) reoriented itself, formed a H-bond with O5, and released a proton to O5, resulting in formation of OH- at both W3 and O5. Once generated, the OH- group at O5 was stable, because the W3…O5 H-bond had already disappeared. A weak binding of H2O at Ca2+ led W3 to reorient and serve as a proton donor to O5 upon over-reduction.


Assuntos
Cianobactérias/química , Modelos Moleculares , Complexo de Proteína do Fotossistema II/química , Cálcio/química , Ligações de Hidrogênio , Manganês/química , Oxigênio/química , Prótons , Água/química
5.
Biochim Biophys Acta Bioenerg ; 1860(10): 148054, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31336104

RESUMO

In cyanobacteria, Glu-244 and Tyr-246 of the Photosystem II (PS II) D1 protein are hydrogen bonded to two water molecules that are part of a hydrogen-bond network between the bicarbonate ligand to a non-heme iron and the cytosol. Ala substitutions were introduced in Synechocystis sp. PCC 6803 to investigate the roles of these residues and the hydrogen-bond network on electron transfer between the primary plastoquinone acceptor, QA, and the secondary plastoquinone acceptor, QB, of the quinone-Fe-acceptor complex. All mutants assembled PS II; however, an increase in the PS II to PS I ratio was apparent, particularly in the E244A:Y246A double mutant. The mutants also showed impaired oxygen evolution and retarded chlorophyll a fluorescence decays following single turnover actinic flashes, which appeared to be primarily due to reduced QB binding in the E244A strain and an enhanced back reaction with the S2 state of the oxygen-evolving complex in the Y246A mutant. Impaired PS II in the Y246A and E244A:Y246A mutants resulted in inactivation of the psbA gene encoding D1. The Y246A and E244A:Y246A mutants also showed high light sensitivity whereas the E244A mutant showed enhanced resilience towards photodamage. Unlike the control strain, all of the mutants were insensitive to the addition of formate or bicarbonate in assays following chlorophyll decay kinetics that reflect electron transfer between QA and QB, suggesting the bicarbonate binding environment was perturbed. Our data also indicate that waters W582 and W622 (PDB: 4UB6) have essential roles in maintaining the architecture of the acceptor side of PS II.


Assuntos
Bicarbonatos/química , Cianobactérias/química , Transporte de Elétrons , Complexo de Proteína do Fotossistema II/química , Plastoquinona/química , Benzoquinonas , Sítios de Ligação , Chlamydomonas reinhardtii , Clorofila/química , Clorofila/metabolismo , Ligações de Hidrogênio , Ferro , Proteínas Mutantes , Oxigênio/química , Oxigênio/metabolismo , Plastoquinona/metabolismo , Synechocystis/genética
6.
Biochim Biophys Acta Mol Cell Res ; 1866(10): 1608-1617, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31295502

RESUMO

Due to the low absorbance in the far-red (FR) and near-infrared (NIR) "optical window", NIR fluorescent proteins (FPs) are powerful tools for deep imaging. Here, we report three new, highly bright NIR FPs termed BDFP1.8, BDFP1.8:1.8 (tandem BDFP1.8) and BDFP1.9, which evolved from a previously reported FR FP, BDFP1.6: a derivative of ApcF2 from Chroococcidiopsis thermalis sp. PCC7203. ApcF2 binds phycocyanobilin (PCB) non-covalently, while BDFPs, the derivatives of ApcF2, can bind biliverdin (BV) covalently. We identified that dimeric BDFP1.8 and monomeric BDFP1.8:1.8 have a 2.4-and 4.4-fold higher effective brightness, respectively, than iRFP720, which has the highest effective brightness among the reported NIR FPs. Monomeric DBFP1.9 (17 kDa) has one of the smallest masses among highly bright FPs in the FR and NIR regions. Enhancing the affinity between the apo-proteins and the BV chromophore is an effective method to improve the effective brightness of biliprotein FPs. Moreover, BDFP1.8 and 1.9 exhibit higher stability to temperature, pH and light than iRFP720. Finally, the highly bright NIR BDFP1.8 together with FR BDFP1.6 could effectively biolabel cells in dual colors.


Assuntos
Proteínas de Bactérias/química , Biliverdina/química , Proteínas Luminescentes/química , Microscopia de Fluorescência/métodos , Animais , Proteínas de Bactérias/metabolismo , Cianobactérias/química , Cianobactérias/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Fluorescência , Células HEK293 , Células HeLa , Humanos , Raios Infravermelhos , Luz , Modelos Moleculares , Imagem Óptica/métodos , Ficobilinas , Ficocianina , Conformação Proteica
7.
Mar Drugs ; 17(7)2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31288394

RESUMO

Cyanothece sp., a coccoid, unicellular, nitrogen-fixing and hydrogen-producing cyanobacterium, has been used in this study to biosynthesize customized gold nanoparticles under certain chemical conditions. The produced gold nanoparticles had a characteristic absorption band at 525-535 nm. Two types of gold nanoparticle, the purple and blue, were formed according to the chemical environment in which the cyanobacterium was grown. Dynamic light scattering was implemented to estimate the size of the purple and blue nanoparticles, which ranged from 80 ± 30 nm and 129 ± 40 nm in diameter, respectively. The highest scattering of laser light was recorded for the blue gold nanoparticles, which was possibly due to their larger size and higher concentration. The appearance of anodic and cathodic peaks in cyclic voltammetric scans of the blue gold nanoparticles reflected the oxidation into gold oxide, followed by the subsequent reduction into the nano metal state. The two produced forms of gold nanoparticles were used to treat isoproterenol-induced myocardial infarction in experimental rats. Both forms of nanoparticles ameliorated myocardial infarction injury, with a slight difference in their curative activity with the purple being more effective. Mechanisms that might explain the curative effect of these nanoparticles on the myocardial infarction were proposed. The morphological, physiological, and biochemical attributes of the Cyanothece sp. cyanobacterium were fundamental for the successful production of "tailored" nanoparticles, and complemented the chemical conditions for the differential biosynthesis process. The present research represents a novel approach to manipulate cyanobacterial cells towards the production of different-sized gold nanoparticles whose curative impacts vary accordingly. This is the first report on that type of manipulated gold nanoparticles biosynthesis which will hopefully open doors for further investigations and biotechnological applications.


Assuntos
Cianobactérias/química , Cyanothece/química , Ouro/química , Ouro/farmacologia , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/química , Infarto do Miocárdio/tratamento farmacológico , Animais , Isoproterenol/química , Luz , Masculino , Miocárdio/química , Nitrogênio/química , Fixação de Nitrogênio/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley
8.
Mar Drugs ; 17(6)2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31163697

RESUMO

Largazole, isolated from a marine Cyanobacterium of the genus Symploca, is a potent and selective Class I HDAC (histone deacetylation enzymes) inhibitor. This natural 16-membered macrocyclic depsipeptide features an interesting side chain unit, namely 3-hydroxy-7-mercaptohept-4-enoic acid, which occurs in many other natural sulfur-containing HDAC inhibitors. Notably, one similar fragment, where the amide moiety replaces the trans alkene moiety, appears in Psammaplin A, another marine natural product with potent HDAC inhibitory activities. Inspired by such a structural similarity, we hypothesized the fluoroolefin moiety would mimic both the alkene moiety in Largazole and the amide moiety in Psammaplin A, and thus designed and synthesized two novel fluoro olefin analogs of Largazole. The preliminary biological assays showed that the fluoro analogs possessed comparable Class I HDAC inhibitory effects, indicating that this kind of modification on the side chain of Largazole was tolerable.


Assuntos
Organismos Aquáticos/química , Cianobactérias/química , Depsipeptídeos/síntese química , Depsipeptídeos/farmacologia , Dissulfetos/química , Inibidores de Histona Desacetilases/farmacologia , Tiazóis/síntese química , Tiazóis/farmacologia , Tirosina/análogos & derivados , Alcenos/química , Depsipeptídeos/química , Ativação Enzimática/efeitos dos fármacos , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/química , Histona Desacetilases/metabolismo , Tiazóis/química , Tirosina/química
9.
Environ Sci Pollut Res Int ; 26(22): 22450-22463, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161548

RESUMO

Zinc oxide (ZnO) nanoparticles are commonly used in sunscreens for their UV-filtering properties. Their growing use can lead to their release into ecosystems, raising question about their toxicity. Effects of these engineered nanomaterials (ENMs) on cyanobacteria, which are important primary producers involved in many biogeochemical cycles, are unknown. In this study, we investigated by several complementary approaches the toxicological effects of two marketed ZnO-ENMs (coated and uncoated) on the model cyanobacteria Synechococcus elongatus PCC 7942. It was shown that despite the rapid adsorption of ENMs on cell surface, toxicity is mainly due to labile Zn released by ENMs. Zn dissipates cell membrane potential necessary for both photosynthesis and respiration, and induces oxidative stress leading to lipid peroxidation and DNA damages. It leads to global downregulation of photosystems, oxidative phosphorylation, and transcription/translation machineries. This also translates into significant decrease of intracellular ATP content and cell growth inhibition. However, there is no major loss of pigments and even rather an increase in exposed cells compared to controls. A proposed way to reduce the environmental impact of Zn would be the improvement of the coating stability to prevent solubility of ZnO-ENMs.


Assuntos
Cianobactérias/efeitos dos fármacos , Nanopartículas/toxicidade , Synechococcus/química , Óxido de Zinco/química , Adsorção , Cianobactérias/química , Dano ao DNA , Ecossistema , Estresse Oxidativo , Fotossíntese , Protetores Solares/química , Óxido de Zinco/toxicidade
10.
Mar Drugs ; 17(6)2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151260

RESUMO

Cyanobacteria are photosynthetic microorganisms that colonize diverse environments worldwide, ranging from ocean to freshwaters, soils, and extreme environments. Their adaptation capacities and the diversity of natural products that they synthesize, support cyanobacterial success in colonization of their respective ecological niches. Although cyanobacteria are well-known for their toxin production and their relative deleterious consequences, they also produce a large variety of molecules that exhibit beneficial properties with high potential in various fields (e.g., a synthetic analog of dolastatin 10 is used against Hodgkin's lymphoma). The present review focuses on the beneficial activities of cyanobacterial molecules described so far. Based on an analysis of 670 papers, it appears that more than 90 genera of cyanobacteria have been observed to produce compounds with potentially beneficial activities in which most of them belong to the orders Oscillatoriales, Nostocales, Chroococcales, and Synechococcales. The rest of the cyanobacterial orders (i.e., Pleurocapsales, Chroococcidiopsales, and Gloeobacterales) remain poorly explored in terms of their molecular diversity and relative bioactivity. The diverse cyanobacterial metabolites possessing beneficial bioactivities belong to 10 different chemical classes (alkaloids, depsipeptides, lipopeptides, macrolides/lactones, peptides, terpenes, polysaccharides, lipids, polyketides, and others) that exhibit 14 major kinds of bioactivity. However, no direct relationship between the chemical class and the respective bioactivity of these molecules has been demonstrated. We further selected and specifically described 47 molecule families according to their respective bioactivities and their potential uses in pharmacology, cosmetology, agriculture, or other specific fields of interest. With this up-to-date review, we attempt to present new perspectives for the rational discovery of novel cyanobacterial metabolites with beneficial bioactivity.


Assuntos
Produtos Biológicos/química , Cianobactérias/química , Descoberta de Drogas/tendências
11.
Biosensors (Basel) ; 9(2)2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-31216673

RESUMO

Cyanobacterial blooms cause local and global health issues by contaminating surface waters. Microcystins and nodularins are cyclic cyanobacterial peptide toxins comprising numerous natural variants. Most of them are potent hepatotoxins, tumor promoters, and at least microcystin-LR is possibly carcinogenic. In drinking water, the World Health Organization (WHO) recommended the provisional guideline value of 1 µg/L for microcystin-LR. For water used for recreational activity, the guidance values for microcystin concentration varies mostly between 4-25 µg/L in different countries. Current immunoassays or lateral flow strips for microcystin/nodularin are based on indirect competitive method, which are generally more prone to sample interference and sometimes hard to interpret compared to two-site immunoassays. Simple, sensitive, and easy to interpret user-friendly methods for first line screening of microcystin/nodularin near water sources are needed for assessment of water quality and safety. We describe the development of a two-site sandwich format lateral-flow assay for the rapid detection of microcystins and nodularin-R. A unique antibody fragment capable of broadly recognizing immunocomplexes consisting of a capture antibody bound to microcystins/nodularin-R was used to develop the simple lateral flow immunoassay. The assay can visually detect the major hepatotoxins (microcystin-LR, -dmLR, -RR, -dmRR, -YR, -LY, -LF -LW, and nodularin-R) at and below the concentration of 4 µg/L. The signal is directly proportional to the concentration of the respective toxin, and the use of alkaline phosphatase activity offers a cost efficient alternative by eliminating the need of toxin conjugates or other labeling system. The easy to interpret assay has the potential to serve as a microcystins/nodularin screening tool for those involved in water quality monitoring such as municipal authorities, researchers, as well as general public concerned of bathing water quality.


Assuntos
Toxinas Bacterianas/análise , Cianobactérias/química , Imunoensaio/instrumentação , Microcistinas/análise , Peptídeos Cíclicos/análise , Carcinógenos/análise , Desenho de Equipamento , Fitas Reagentes/análise , Água/análise
12.
Int J Biol Macromol ; 134: 368-378, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31059742

RESUMO

Cyanobacteria are an immense source of innovative classes of pharmacologically active compounds exhibiting various biological activities ranging from antioxidants, antibiotics, anticancer, anti-inflammatory to anti-Alzheimer's disease. In the present study, we primarily targeted the inhibition of Beta-site amyloid precursor protein cleaving enzyme-1 (BACE1) by a naturally occurring cyanobacterial protein phycoerythrin (C-PE). BACE1 cleaves amyloid-ß precursor protein (APP) and leads to accumulation of neurotoxic amyloid beta (Aß) plaques in the brain, as an attribute of Alzheimer's disease (AD). Inhibition of BACE1 was measured in terms of their association and dissociation rate constants, thermodynamics of binding using surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). The kinetic parameters for enzyme activity were also measured using synthetic decapeptide as a substrate. We further validated the potential of PE by in-vivo histopathological staining of Aß aggregate mutant Caenorhabditis elegans CL4176 by Thioflavin-T. The present studies pave the way for the application of naturally occurring C-PE as a putative therapeutic drug for the AD.


Assuntos
Cianobactérias/química , Ficoeritrina/química , Ficoeritrina/farmacologia , Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/genética , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Animais , Ácido Aspártico Endopeptidases/química , Ácido Aspártico Endopeptidases/genética , Ácido Aspártico Endopeptidases/metabolismo , Caenorhabditis elegans , Cianobactérias/metabolismo , Ativação Enzimática , Humanos , Imuno-Histoquímica , Cinética , Conformação Molecular , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Redobramento de Proteína , Proteínas Recombinantes , Relação Estrutura-Atividade
13.
Molecules ; 24(9)2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31058803

RESUMO

Cyanobacteriochromes are compact and spectrally diverse photoreceptor proteins that are promising candidates for biotechnological applications. Computational studies can contribute to an understanding at a molecular level of their wide spectral tuning and diversity. In this contribution, we benchmark methods to model a 110 nm shift in the UV/Vis absorption spectrum from a red- to a green-absorbing form of the cyanobacteriochrome Slr1393g3. Based on an assessment of semiempirical methods to describe the chromophore geometries of both forms in vacuo, we find that DFTB2+D leads to structures that are the closest to the reference method. The benchmark of the excited state calculations is based on snapshots from quantum mechanics/molecular mechanics molecular dynamics simulations. In our case, the methods RI-ADC(2) and sTD-DFT based on CAM-B3LYP ground state calculations perform the best, whereas no functional can be recommended to simulate the absorption spectra of both forms with time-dependent density functional theory. Furthermore, the difference in absorption for the lowest energy absorption maxima of both forms can already be modelled with optimized structures, but sampling is required to improve the shape of the absorption bands of both forms, in particular for the second band. This benchmark study can guide further computational studies, as it assesses essential components of a protocol to model the spectral tuning of both cyanobacteriochromes and the related phytochromes.


Assuntos
Cianobactérias/metabolismo , Fitocromo/química , Proteínas de Bactérias/química , Benchmarking , Cianobactérias/química , Simulação de Dinâmica Molecular , Processos Fotoquímicos , Conformação Proteica , Teoria Quântica
14.
Mar Drugs ; 17(5)2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-31083362

RESUMO

Obesity is a complex disease resulting in several metabolic co-morbidities and is increasing at epidemic rates. The marine environment is an interesting resource of novel compounds and in particular cyanobacteria are well known for their capacity to produce novel secondary metabolites. In this work, we explored the potential of cyanobacteria for the production of compounds with relevant activities towards metabolic diseases using a blend of target-based, phenotypic and zebrafish assays as whole small animal models. A total of 46 cyanobacterial strains were grown and biomass fractionated, yielding in total 263 fractions. Bioactivities related to metabolic function were tested in different in vitro and in vivo models. Studying adipogenic and thermogenic gene expression in brown adipocytes, lipid metabolism and glucose uptake in hepatocytes, as well as lipid metabolism in zebrafish larvae, we identified 66 (25%) active fractions. This together with metabolite profiling and the evaluation of toxicity allowed the identification of 18 (7%) fractions with promising bioactivity towards different aspects of metabolic disease. Among those, we identified several known compounds, such as eryloside T, leptosin F, pheophorbide A, phaeophytin A, chlorophyll A, present as minor peaks. Those compounds were previously not described to have bioactivities in metabolic regulation, and both known or unknown compounds could be responsible for such effects. In summary, we find that cyanobacteria hold a huge repertoire of molecules with specific bioactivities towards metabolic diseases, which needs to be explored in the future.


Assuntos
Fármacos Antiobesidade/farmacologia , Cianobactérias/química , Obesidade/tratamento farmacológico , Adipócitos Marrons/efeitos dos fármacos , Adipócitos Marrons/fisiologia , Animais , Fármacos Antiobesidade/química , Fármacos Antiobesidade/toxicidade , Cianobactérias/crescimento & desenvolvimento , Cianobactérias/metabolismo , Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Células Hep G2 , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Obesidade/metabolismo , PPAR gama/metabolismo , Testes de Toxicidade , Proteína Desacopladora 1/metabolismo , Peixe-Zebra
15.
J Phys Chem Lett ; 10(11): 2938-2943, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31074620

RESUMO

Alignment of molecules through electric fields minimizes the averaging over orientations, e.g., in single-particle-imaging experiments. The response of molecules to external ac electric fields is governed by their polarizability tensor, which is usually calculated using quantum chemistry methods. These methods are not feasible for large molecules. Here, we calculate the polarizability tensor of proteins using a regression model that correlates the polarizabilities of the 20 amino acids with perfect conductors of the same shape. The dielectric constant of the molecules could be estimated from the slope of the regression line based on the Clausius-Mossotti equation. We benchmark our predictions against the quantum chemistry results for the Trp cagemini protein and the measured dielectric constants of larger proteins. Our method has applications in computing laser alignment of macromolecules, for instance, benefiting single-particle imaging, as well as for estimation of the optical and electrostatic characteristics of proteins and other macromolecules.


Assuntos
Aminoácidos/química , Simulação por Computador , Anabaena variabilis/química , Cianobactérias/química , Inibidor da Ligação a Diazepam/química , Glutarredoxinas/química , Humanos , Plastocianina/química , Teoria Quântica , Análise de Regressão , Eletricidade Estática
16.
J Am Soc Mass Spectrom ; 30(8): 1373-1384, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31093948

RESUMO

Marine sponges and their associated symbionts produce a structurally diverse and complex set of natural products including alkaloids, terpenoids, peptides, lipids, and steroids. A single sponge with its symbionts can produce all of the above-mentioned classes of molecules and their analogs. Most approaches to evaluating sponge chemical diversity have focused on major metabolites that can be isolated and characterized; therefore, a comprehensive evaluation of intra- (within a molecular family; analogs) and inter-chemical diversity within a single sponge remains incomplete. We use a combination of metabolomics tools, including a supervised approach via manual library search and literature search, and an unsupervised approach via molecular networking and MS2LDA analysis to describe the intra and inter-chemical diversity present in Smenospongia aurea. Furthermore, we use imaging mass spectrometry to link this chemical diversity to either the sponge or the associated cyanobacteria. Using these approaches, we identify seven more molecular features that represent analogs of four previously known peptide/polyketide smenamides and assign the biosynthesis of these molecules to the symbiotic cyanobacteria by imaging mass spectrometry. We extend this analysis to a wide diversity of molecular classes including indole alkaloids and meroterpenes.


Assuntos
Produtos Biológicos/análise , Alcaloides Indólicos/análise , Peptídeos/análise , Policetídeos/análise , Poríferos/química , Animais , Produtos Biológicos/metabolismo , Cianobactérias/química , Cianobactérias/metabolismo , Alcaloides Indólicos/metabolismo , Espectrometria de Massas/métodos , Metabolômica/métodos , Peptídeos/metabolismo , Policetídeos/metabolismo , Poríferos/metabolismo , Poríferos/microbiologia , Simbiose , Terpenos/análise , Terpenos/metabolismo
17.
Aquat Toxicol ; 212: 214-221, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31132739

RESUMO

Beta-N-methylamino-L-alanine (BMAA) is a non-proteinogenic amino acid produced by several cyanobacteria species. It is considered to be a potent neurotoxin. Although its neurotoxic effects are well studied, other negative effects of BMAA have not yet been completely elucidated. In the present study, we studied the cytotoxic effects of a wide range of concentrations of BMAA (0.25-2.0 mM) on a stable fish immune cell line (CLC) obtained from carp monocytes. The cells exposed to higher concentrations of BMAA exhibited an altered morphology, changed ATP levels, and reduced proliferation. On the basis of toxic effects of BMAA on lysosomes, mitochondrial dehydrogenases activity, and cell membrane integrity, we determined its cytotoxic concentrations. We also investigated effects of the toxin at non-cytotoxic concentrations on the basic functions of CLC cells. BMAA did not affect the production and release of IL-1ß or phagocytic activity of the cells. However, higher non-toxic BMAA concentrations altered the levels of extracellular and intracellular total proteins compared to those in control cells.


Assuntos
Diamino Aminoácidos/toxicidade , Peixes , Animais , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cianobactérias/química , Ativação Enzimática/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Oxirredutases/metabolismo , Poluentes Químicos da Água/toxicidade
18.
Anal Bioanal Chem ; 411(20): 5267-5275, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31129692

RESUMO

Microcystins are cyclic peptide toxins with hepatotoxic and tumor-promoting properties, which are produced in significant quantities (up to tens of µg/L) in freshwater cyanobacterial water blooms. Several studies reported microcystin accumulation in fish with possible food transfer to humans. These compounds are further metabolized to cysteine and glutathione conjugates which can be present in tissues in significant concentrations. In this study, we focused on the development and evaluation of robust and highly sensitive SPE-LC-MS/MS method for the analysis of microcystin conjugates in fish tissue samples. For the first time, we demonstrate the use of isotopically labeled internal standards which are essential for accurate and precise determination of analytes in complex biotic matrices. LLOQs of respective microcystin conjugates (signal-to-noise ratio; S/N > 10, peak-to-peak method) ranged from 3.3 to 5.0 ng/g of tissue fresh weight (FW). The calibration was linear within a range of concentrations from 1 to 70 ng/mL for all analyzed conjugates. The precision and repeatability of the method were very good with recoveries in the range of 88.5-107.6% and relative standard deviations between 8.8 and 13.2% for all analytes. In the follow-up study, fully validated method was used for the determination of microcystin conjugate levels in common carp exposed to microcystin-containing cyanobacterial biomass under controlled conditions. Significant amounts of microcystin conjugates (up to 55 ng/g) were found in the tissues of fish after 7 weeks of exposure. Our method was shown to be robust, sensitive, selective, and suitable for the determination of trace levels of microcystin conjugates in fish tissues.


Assuntos
Cromatografia Líquida/métodos , Cianobactérias/química , Cisteína/análise , Glutationa/análise , Microcistinas/análise , Espectrometria de Massas em Tandem/métodos , Biomassa , Limite de Detecção , Microcistinas/química , Técnica de Diluição de Radioisótopos , Reprodutibilidade dos Testes
19.
Mar Drugs ; 17(4)2019 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-31010222

RESUMO

Ototoxicity, or adverse pharmacological effects on the inner ear or auditory nerve, is a common side effect of cisplatin, a platinum-based drug widely used in anticancer chemotherapy. Although the incidence of ototoxicity is high among patients that receive cisplatin therapy, there is currently no effective treatment for it. The generation of excessive reactive oxygen species (ROS) is considered to be the major cause of cisplatin-induced ototoxicity. C-phycocyanin (C-PC), a blue phycobiliprotein found in cyanobacteria and red algae, has antioxidant and anticancer activities in different experimental models in vitro and in vivo. Thus, we tested the ability of C-PC from Limnothrix sp. KNUA002 to protect auditory cells from cisplatin-induced ototoxicity in vitro. Pretreatment with C-PC from Limnothrix sp. KNUA002 inhibited apoptosis and protected mitochondrial function by preventing ROS accumulation in cisplatin-treated House Ear Institute-Organ of Corti 1 (HEI-OC1) cells, a mouse auditory cell line. Cisplatin increased the expression of Bax and reduced the expression of Bcl-2, which activate and inhibit, respectively, the mitochondrial apoptotic pathway in response to oxidative stress. Pretreatment with C-PC prior to cisplatin treatment caused the Bax and Bcl-2 levels to stay close to the levels in untreated control cells. Our results suggest that C-PC from Limnothrix sp. KNUA002 protects cells against cisplatin-induced cytotoxicity by inhibiting the mitochondrial apoptotic pathway.


Assuntos
Antineoplásicos/toxicidade , Cisplatino/toxicidade , Cianobactérias/química , Células Ciliadas Auditivas/efeitos dos fármacos , Perda Auditiva/induzido quimicamente , Perda Auditiva/tratamento farmacológico , Ficocianina/farmacologia , Animais , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cianobactérias/metabolismo , Células Ciliadas Auditivas/metabolismo , Perda Auditiva/metabolismo , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Substâncias Protetoras/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteína X Associada a bcl-2/metabolismo
20.
Mar Drugs ; 17(4)2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30999602

RESUMO

Marine organisms, particularly cyanobacteria, are important resources for the production of bioactive secondary metabolites for the treatment of human diseases. In this study, a bioassay-guided approach was used to discover metabolites with lipid-reducing activity. Two chlorophyll derivatives were successfully isolated, the previously described 132-hydroxy-pheophytin a (1) and the new compound 132-hydroxy-pheofarnesin a (2). The structure elucidation of the new compound 2 was established based on one- and two-dimensional (1D and 2D) NMR spectroscopy and mass spectrometry. Compounds 1 and 2 showed significant neutral lipid-reducing activity in the zebrafish Nile red fat metabolism assay after 48 h of exposure with a half maximal effective concentration (EC50) of 8.9 ± 0.4 µM for 1 and 15.5 ± 1.3 µM for 2. Both compounds additionally reduced neutral lipid accumulation in 3T3-L1 multicellular spheroids of murine preadipocytes. Molecular profiling of mRNA expression of some target genes was evaluated for the higher potent compound 1, which indicated altered peroxisome proliferator activated receptor gamma (PPARγ) mRNA expression. Lipolysis was not affected. Different food materials (Spirulina, Chlorella, spinach, and cabbage) were evaluated for the presence of 1, and the cyanobacterium Spirulina, with GRAS (generally regarded as safe) status for human consumption, contained high amounts of 1. In summary, known and novel chlorophyll derivatives were discovered from marine cyanobacteria with relevant lipid-reducing activities, which in the future may be developed into nutraceuticals.


Assuntos
Clorofila/análogos & derivados , Clorofila/farmacologia , Cianobactérias/química , Metabolismo dos Lipídeos/efeitos dos fármacos , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Brassica/química , Proteínas de Transporte/metabolismo , Linhagem Celular , Chlorella/química , Clorofila/química , Clorofila/isolamento & purificação , Ácido Graxo Sintase Tipo I/metabolismo , Lipólise , Camundongos , PPAR gama/metabolismo , Sirtuína 1/metabolismo , Spinacia oleracea/química , Spirulina/química , Peixe-Zebra
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