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1.
Sensors (Basel) ; 24(7)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38610468

RESUMO

The study explores the feasibility of adapting the EOStat crop monitoring system, originally designed for monitoring crop growth conditions in Poland, to fulfill the requirements of a similar system in Ukraine. The system utilizes satellite data and agrometeorological information provided by the Copernicus program, which offers these resources free of charge. To predict crop yields, the system uses several factors, such as vegetation condition indices obtained from Sentinel-3 Ocean and Land Color Instrument (OLCI) optical and Sea and Land Surface Temperature Radiometer (SLSTR). It also incorporates climate information, including air temperature, total precipitation, surface radiation, and soil moisture. To identify the best predictors for each administrative unit, the study utilizes a recursive feature elimination method and employs the Extreme Gradient Boosting regressor, a machine learning algorithm, to forecast crop yields. The analysis indicates a noticeable decrease in crop losses in 2022 in certain regions of Ukraine, compared to the previous year (2021) and the 5-year average (2017-2021), specifically for winter crops and maize. Considering the reduction in yield, it is estimated that the decline in production of winter crops in 2022 was up to 20%, while for maize, it was up to 50% compared to the decline in production.

2.
Molecules ; 27(1)2021 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-35011417

RESUMO

The aim of this study was to estimate the contamination of grain coffee, roasted coffee, instant coffee, and cocoa purchased in local markets with ochratoxin A (OTA) and its isomerization product 2'R-ochratoxin A (2'R-OTA), and to assess risk of dietary exposure to the mycotoxins. OTA and 2'R-OTA content was determined using the HPLC chromatography with immunoaffinity columns dedicated to OTA. OTA levels found in all the tested samples were below the maximum limits specified in the European Commission Regulation EC 1881/2006. Average OTA concentrations calculated for positive samples of grain coffee/roasted coffee/instant coffee/cocoa were 0.94/0.79/3.00/0.95 µg/kg, with the concentration ranges: 0.57-1.97/0.44-2.29/0.40-5.15/0.48-1.97 µg/kg, respectively. Average 2'R-OTA concentrations calculated for positive samples of roasted coffee/instant coffee were 0.90/1.48 µg/kg, with concentration ranges: 0.40-1.26/1.00-2.12 µg/kg, respectively. In turn, diastereomer was not found in any of the tested cocoa samples. Daily intake of both mycotoxins with coffee/cocoa would be below the TDI value even if the consumed coffee/cocoa were contaminated with OTA/2'R-OTA at the highest levels found in this study. Up to now only a few papers on both OTA and 2'R-OTA in roasted food products are available in the literature, and this is the first study in Poland.


Assuntos
Carcinógenos/análise , Análise de Alimentos , Contaminação de Alimentos/análise , Ocratoxinas/análise , Cacau/química , Carcinógenos/química , Cromatografia Líquida de Alta Pressão/métodos , Café/química , Dieta , Grão Comestível/química , Análise de Alimentos/métodos , Humanos , Estrutura Molecular , Micotoxinas/análise , Ocratoxinas/química , Medição de Risco
3.
Molecules ; 23(4)2018 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-29677133

RESUMO

Mycotoxins are secondary fungal metabolites, toxic to humans, animals and plants. Under the influence of various factors, mycotoxins may undergo modifications of their chemical structure. One of the methods of mycotoxin modification is a transformation occurring in plant cells or under the influence of fungal enzymes. This paper reviews the current knowledge on the natural occurrence of the most important trichothecenes and zearalenone in cereals/cereal products, their metabolism, and the potential toxicity of the metabolites. Only very limited data are available for the majority of the identified mycotoxins. Most studies concern biologically modified trichothecenes, mainly deoxynivalenol-3-glucoside, which is less toxic than its parent compound (deoxynivalenol). It is resistant to the digestion processes within the gastrointestinal tract and is not absorbed by the intestinal epithelium; however, it may be hydrolysed to free deoxynivalenol or deepoxy-deoxynivalenol by the intestinal microflora. Only one zearalenone derivative, zearalenone-14-glucoside, has been extensively studied. It appears to be more reactive than deoxynivalenol-3-glucoside. It may be readily hydrolysed to free zearalenone, and the carbonyl group in its molecule may be easily reduced to α/ß-zearalenol and/or other unspecified metabolites. Other derivatives of deoxynivalenol and zearalenone are poorly characterised. Moreover, other derivatives such as glycosides of T-2 and HT-2 toxins have only recently been investigated; thus, the data related to their toxicological profile and occurrence are sporadic. The topics described in this study are crucial to ensure food and feed safety, which will be assisted by the provision of widespread access to such studies and obtained results.


Assuntos
Grão Comestível/microbiologia , Fusarium/fisiologia , Micotoxinas/metabolismo , Animais , Biotransformação , Metabolismo Energético , Humanos , Hidrólise , Inativação Metabólica , Estrutura Molecular , Micotoxinas/química
4.
Langmuir ; 32(16): 4059-65, 2016 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-27054848

RESUMO

Interaction of polystyrene-block-poly(methacrylic acid) micelles (PS-PMAA) with cationic surfactant N-dodecylpyridinium chloride (DPCl) in alkaline aqueous solutions was studied by static and dynamic light scattering, SAXS, cryogenic transmission electron microscopy (cryo-TEM), isothermal titration calorimetry (ITC), and time-resolved fluorescence spectroscopy. ITC and fluorescence measurements show that there are two distinct regimes of surfactant binding in the micellar corona (depending on the DPCl content) caused by different interactions of DPCl with PMAA in the inner and outer parts of the corona. The compensation of the negative charge of the micellar corona by DPCl leads to the aggregation of PS-PMAA micelles, and the micelles form colloidal aggregates at a certain critical surfactant concentration. SAXS shows that the aggregates are formed by individual PS-PMAA micelles with intact cores and collapsed coronas interconnected with surfactant micelles by electrostatic interactions. Unlike polyelectrolyte-surfactant complexes formed by free polyelectrolyte chains, the PMAA/DPCl complex with collapsed corona does not contain surfactant micelles.

5.
Foods ; 11(21)2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36360078

RESUMO

Maize (Zea mays L.) is one of the most susceptible crops to pathogenic fungal infections, and in particular to the Fusarium species. Secondary metabolites of Fusarium spp.-mycotoxins are not only phytotoxic, but also harmful to humans and animals. They can cause acute or chronic diseases with various toxic effects. The European Union member states apply standards and legal regulations on the permissible levels of mycotoxins in food and feed. This review summarises the most recent knowledge on the occurrence of toxic secondary metabolites of Fusarium in maize, taking into account modified forms of mycotoxins, the progress in research related to the health effects of consuming food or feed contaminated with mycotoxins, and also the development of biological methods for limiting and/or eliminating the presence of the same in the food chain and in compound feed.

6.
J Agric Food Chem ; 70(14): 4291-4302, 2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35362967

RESUMO

Fusarium head blight (FHB) caused by pathogenic species of Fusarium fungi is one of the most important diseases of cereal plants and a factor contributing to losses in plant production. The growth of FHB-associated species is often accompanied by biosynthesis of secondary metabolites─mycotoxins, which serve as a virulence factor. The aim of the study was to evaluate the ratios between deoxynivalenol (DON) and nivalenol (NIV) and their derivatives in the ears of six cultivars of winter wheat with varying resistance to FHB, taking into account a range of factors (weather conditions, location, cultivar, and year) after inoculation with Fusarium culmorum, during a 3 year field experiment, 2018-2020. The presence of toxins in the ears was measured within 21 days of inoculation. The toxins were found in the ears as soon as on the third day from the start of the experiment, whereas relative humidity higher than 80% was a decisive factor for FHB incidence. All wheat cultivars showed the ability to biotransform DON and NIV present in the ears to glucosides, that is, deoxynivalenol-3-glucoside (DON-3G) and nivalenol-3-glucoside (NIV-3G). The levels of these metabolites showed significant correlation with the levels of their basic analogues. In most cases, higher levels of DON and NIV in wheat ears and higher levels of their metabolites were observed, but the relative levels of DON-3G/DON and NIV-3G/NIV at relatively high levels of toxins were lower compared to the ear samples with relatively low toxin levels. The presented results are the first studies, which systematically correlate a variety of wheat cultivars with their extent to glucosylate trichothecenes.


Assuntos
Fusarium , Micotoxinas , Tricotecenos , Fusarium/metabolismo , Glucosídeos/metabolismo , Micotoxinas/metabolismo , Doenças das Plantas/microbiologia , Tricotecenos/metabolismo , Triticum/metabolismo
7.
Toxins (Basel) ; 13(12)2021 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-34941704

RESUMO

This study investigated the impact of malting of six wheat cultivars inoculated with Fusarium culmorum on the dynamics of content changes of selected Fusarium toxins. The grains of all the tested cultivars showed a high content of deoxynivalenol (DON), zearalenone (ZEN), and their derivatives, whereas nivalenol (NIV) and its glucoside were found only in the Legenda cultivar. Our experiments confirmed that the malting process of wheat grain enables the secondary growth of Fusarium, and mycotoxin biosynthesis. The levels of toxins in malt were few-fold higher than those in grain; an especially high increase was noted in the case of ZEN and its sulfate as the optimal temperature and pH conditions for the biosynthesis of these toxins by the pathogen are similar to those used in the grain malting process. This is the first paper reporting that during the malting process, biosynthesis of ZEN sulfate occurs, instead of glycosylation, which is a typical modification of mycotoxins by plant detoxication enzymes.


Assuntos
Manipulação de Alimentos , Fusarium/metabolismo , Triticum/microbiologia , Biotransformação , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Tricotecenos/metabolismo , Triticum/genética , Zearalenona/metabolismo
8.
Toxins (Basel) ; 13(2)2021 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-33670424

RESUMO

The transformation of deoxynivalenol (DON), nivalenol (NIV), and their glucosides (DON3G and NIV3G) during the malting of grains of two wheat varieties was studied. The concentration of DON3G and NIV3G started to increase significantly before the concentration of DON and NIV increased. This may reflect the transformation of the parent mycotoxin forms into their glucosides due to xenobiotic detoxification reactions. After a sharp rise during the last 2 days of the process (day 6 and 7), the DON concentration reached 3010 ± 338 µg/kg in the Legenda wheat-based malt and 4678 ± 963 µg/kg in the Pokusa wheat-based malt. The NIV concentration, at 691 ± 65 µg/kg, remained the same as that in the dry grain. The concentration of DON3G in the Legenda and Pokusa wheat-based malt was five and three times higher, respectively, than that in the steeped grain. The concentration of NIV3G in the Legenda wheat-based malt was more than twice as high as that in the steeped grain. The sharp increase in the concentration of DON at the end of the malting process reflected the high pathogen activity. We set aside some samples to study a batch that was left undisturbed without turning and aeration, for the entire period of malting. The concentration of DON in the malt produced from the latter batch was 135% and 337% higher, for Legenda and Pokusa, respectively, than that in the malt produced from the batch that was turned and aerated. The NIV concentration was 22% higher in the latter batch.


Assuntos
Grão Comestível/microbiologia , Manipulação de Alimentos , Microbiologia de Alimentos , Fusarium/metabolismo , Tricotecenos/análise , Triticum/microbiologia , Biotransformação , Glucosídeos , Fatores de Tempo
9.
Toxins (Basel) ; 12(6)2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32545232

RESUMO

An increasing number of studies have found that modified mycotoxins, such as free mycotoxins, naturally occur in food, and severely impact food safety. The present study investigated concentrations of trichothecenes nivalenol (NIV), deoxynivalenol (DON), and zearalenone (ZEN), together with their modified forms, nivalenol-3-glucoside (NIV-3G), deoxynivalenol-3-glucoside (DON-3G), and zearalenone-14-glucoside (ZEN-14G) and zearalenone-14-sulfate (ZEN-14S), respectively, at successive stages of malt loaf production (flour, dough kneading/fermentation, loaf baking). Toxins in bakery products originate in flour produced from wheat grain that is naturally contaminated with Fusarium culmorum. Mycotoxin concentrations were determined using high-performance liquid chromatography-high resolution mass spectrometry, and did not significantly change during the successive stages of bread production. After the dough kneading/fermentation stage, concentrations of NIV-3G and DON-3G were slightly increased, whereas those of ZEN and ZEN-14S were slightly decreased. The largest average decrease (21%) was found in ZEN-14G. After the baking stage, the average concentrations of NIV-3G, DON-3G, ZEN-14S, and ZEN-14G in the loaf crumb and crust decreased by 23%, 28%, 27%, and 20%, respectively, compared with those in the dough. During this technical process, the concentration of ZEN-14G in loaf crumb significantly decreased by an average of 48%, and those of ZEN, ZEN-14S, and ZEN-14G in loaf crust decreased by an average of 29%, 42%, and 48%, respectively. Considering the possibility of modified mycotoxins degradation to free forms, as well as the ability to synthesize them from free forms during technological processes, it would be prudent to consider them together during analysis.


Assuntos
Pão/microbiologia , Grão Comestível/microbiologia , Farinha/microbiologia , Microbiologia de Alimentos , Fusarium/metabolismo , Micotoxinas/metabolismo , Triticum/microbiologia , Biotransformação , Culinária , Fermentação , Temperatura Alta
10.
Toxins (Basel) ; 11(12)2019 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-31835298

RESUMO

Eighty-seven samples of malt from several Polish malting plants and 157 beer samples from the beer available on the Polish market (in 2018) were tested for Fusarium mycotoxins (deoxynivalenol (DON), nivalenol (NIV)), and their modified forms ((deoxynivalenol-3-glucoside (DON-3G), nivalenol-3-glucoside (NIV-3G), 3-acetyldeoxynivalenol (3-AcDON)). DON and its metabolite, DON-3G, were found the most, among the samples analyzed; DON and DON-3G were present in 90% and 91% of malt samples, and in 97% and 99% of beer samples, respectively. NIV was found in 24% of malt samples and in 64% of beer samples, and NIV-3G was found in 48% of malt samples and 39% of beer samples. In the malt samples, the mean concentration of DON was 52.9 µg/kg (range: 5.3-347.6 µg/kg) and that of DON-3G was 74.1 µg/kg (range: 4.4-410.3 µg/kg). In the beer samples, the mean concentration of DON was 12.3 µg/L (range: 1.2-156.5 µg/L) and that of DON-3G was 7.1 µg/L (range: 0.6-58.4 µg/L). The concentrations of other tested mycotoxins in the samples of malt and beer were several times lower. The risk of exposure to the tested mycotoxins, following the consumption of beer in Poland, was assessed. The corresponding probable daily intakes (PDIs) remained a small fraction of the tolerable daily intake (TDI). However, in the improbable worst-case scenario, in which every beer bottle consumed would be contaminated with mycotoxins present at the highest level observed among the analyzed beer samples, the PDI would exceed the TDI for DON and its metabolite after the consumption of a single bottle (0.5 L) of beer.


Assuntos
Cerveja/análise , Contaminação de Alimentos/análise , Hordeum , Tricotecenos/análise , Adulto , Exposição Dietética , Humanos , Polônia , Medição de Risco
11.
Toxins (Basel) ; 11(2)2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30717289

RESUMO

Cross-interaction of antibodies within the immunoaffinity columns used in this study facilitated the simultaneous determination of nivalenol (NIV), deoxynivalenol (DON), their glucoside derivatives (NIV-3G, DON-3G), and 3-acetyl-deoxynivalenol (3-AcDON) in wheat grain harvested in various regions of Poland. In Poland, 2018 was a warm, dry agricultural season, and hence, was relatively less favourable for cereal cultivation than 2017. Data on the natural occurrence of NIV-3G in wheat grain are among the first published in the literature. DON was the most frequently found mycotoxin in the tested samples; the percentage occurrence of DON-positive samples was 92% in 2017 and 61% in 2018. Moreover, DON concentrations were generally higher in 2017 samples (5.2⁻1670.7 µg/kg) than those in 2018 samples (range 5.0⁻461.7 µg/kg). A similar pattern was found for DON-3G. However, no statistically significant differences between the samples from the two agricultural seasons were observed for the other three mycotoxins that were analysed, and their concentrations were generally considerably lower. DON was strongly correlated with DON-3G (correlation coefficient r = 0.9558), while NIV was strongly correlated with NIV-3G (r = 0.9442). The percentage occurrence of NIV-3G- and DON-3G-positive samples was 14% in 2017 and 49% in 2018. The NIV-3G/NIV ratio was 5.9⁻35.7%, while the DON-3G/DON ratio range was 3.2⁻53.6%. In 2018, wheat samples from Southern Poland exhibited statistically significantly higher levels of DON than those from Northern Poland. The dry and hot summer of 2018 not only reduced wheat yields, but also limited development of Fusarium spp. Therefore, grain harvested that year was generally contaminated with relatively low levels of mycotoxins. Lower levels of DON were also accompanied by lesser amounts of DON-derivatives.


Assuntos
Grão Comestível/química , Contaminação de Alimentos/análise , Glucosídeos/análise , Tricotecenos/análise , Triticum , Agricultura , Monitoramento Ambiental , Polônia , Estações do Ano
12.
Toxins (Basel) ; 10(2)2018 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-29438296

RESUMO

The presence of mycotoxins in cereal grain is a very important food safety factor. The occurrence of "masked" mycotoxins has been intensively investigated in recent years. In this study, the occurrence of nivalenol, deoxynivalenol-3-glucoside, and deoxynivalenol in 92 samples of winter wheat from Polish cultivars was determined. The frequency of the occurrence of deoxynivalenol and nivalenol in the samples was 83% and 70%, respectively. The average content of the analytes was: for deoxynivalenol 140.2 µg/kg (10.5-1265.4 µg/kg), for nivalenol 35.0 µg/kg (5.1-372.5 µg/kg). Deoxynivalenol-3-glucoside, the formation of which is connected with the biotransformation pathway in plants, was present in 27% of tested wheat samples; its average content was 41.9 µg/kg (15.8-137.5 µg/kg). The relative content of deoxynivalenol-3-glucoside (DON-3G) compared to deoxynivalenol (DON) in positive samples was 4-37%. Despite the high frequency of occurrence of these mycotoxins, the quality of wheat from the 2016 season was good. The maximum content of DON, as defined in EU regulations (1250 µg/kg), was exceeded in only one sample. Nevertheless, the presence of a glycosidic derivative of deoxynivalenol can increase the risk to food safety, as it can be hydrolyzed by intestinal microflora.


Assuntos
Grão Comestível/química , Glucosídeos/análise , Tricotecenos/análise , Triticum , Monitoramento Ambiental , Contaminação de Alimentos/análise , Polônia
13.
Biochim Biophys Acta ; 1722(2): 224-33, 2005 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-15725392

RESUMO

The biological properties of bisquaternary ammonium salts, which are derivatives of N,N-bisdimethyl-1,2-ethanediamine (bis-C(n)BEC), of general formula /C(n)H(2n+1)OOCCH2(CH3)2N(+)CH2CH2N(+)(CH3)2CH2COOC(n)H(2n+1)/2Cl-, were investigated (n=10, 12, 14). The interaction with model membrane was studied by differential scanning calorimetry experiments, and the apparent adiabatic molar compressibility of their solution as a function of concentration was obtained by sound velocity measurements. Their biological activities were assayed by Electrophoresis Mobility Shift, MTT proliferation, and transient transfection. All the investigated compounds interact with the DNA and are able to transfect DNA, when they are co-formulated with DOPE, with an efficiency significantly greater than that of a standard commercial transfection reagent. Bis-C(14)BEC is the only molecule able to deliver DNA inside the cells without a helper lipid, as shown by EGFP expression, albeit with a low efficiency in comparison with a standard commercial transfection reagent. This may be due to a slightly different interaction of bis-C14BEC from bis-C10BEC and bis-C12BEC with phospholipid bilayers. Bis-C10BEC and bis-C12BEC show a slight fluidizing effect, while bis-C14BEC increases stability of both the gel and the rippled gel phases.


Assuntos
Cloreto de Amônio/química , Varredura Diferencial de Calorimetria , Técnicas de Transferência de Genes , Cinética , Soluções , Estresse Mecânico
14.
Fitoterapia ; 103: 71-82, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25771121

RESUMO

Isoxanthohumol (IXN), apart from xanthohumol (XN) and 8-prenylnaringenin (8PN), is one of the most important prenylflavonoids found in hops. Another natural source of this compound is a shrub Sophora flavescens, used in traditional Chinese medicine. Main dietary source of IXN is beer, and the compound is produced from XN during wort boiling. In the human body, the compound is O-demethylated to 8PN, the strongest known phytoestrogen. This process takes place in the liver and in the intestine, where it is mediated by local microflora. It has been reported in some studies that even though beer contains small amounts of hops and its preparations, these compounds may affect the functioning of the human body. IXN exhibits an antiproliferative activity against human cell lines typical for breast cancer (MCF-7), ovarian cancer (A-2780), prostate cancer (DU145 and PC-3), and colon cancer (HT-29 and SW620) cells. It strongly inhibits the activation of the following carcinogens: 2-amino-3-methylimidazol-[4,5-f]quinoline and aflatoxin B1 (AFB1) via human cytochrome P450 (CYP1A2). It also inhibits the production of prostate specific antigen (PSA). IXN significantly reduces the expression of transforming growth factor-ß (TGF-ß) in the case of invasive breast cancer MDA-MB-231. It interferes with JAK/STAT signaling pathway and inhibits the expression of pro1inflammatory genes in the monoblastic leukemia cell line (MonoMac6). It activates apoptosis in human umbilical vein endothelial cells (HUVEC) and human aortic smooth muscle cells (HASMCs). In addition, IXN shows an antiviral activity towards herpes viruses (HSV1 and HSV2) and bovine viral diarrhea virus (BVDV).


Assuntos
Flavonoides/farmacologia , Humulus/química , Xantonas/farmacologia , Cerveja , Linhagem Celular Tumoral/efeitos dos fármacos , Humanos , Estrutura Molecular
15.
Z Naturforsch C J Biosci ; 59(11-12): 782-6, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15666534

RESUMO

The aim of the study was to assay antibacterial and antifungal activity of newly synthesised N-alkoxycarbonylmethyl-N-alkyl-piperidinium chlorides. The compounds tested were found to inhibit the growth of some Gram-negative bacteria, Gram-positive strains and some representatives of yeast-type Candida. From microbiological experiments two of the compounds tested, N-dodecyloxycarbonylmethyl-N-methyl-piperidinium chloride (3) and N-dodecyl-N-ethoxycarbonylmethyl-piperidinium chloride (6), emerged as more active than the other compounds. Since the resistance of biofilms to biocides should be noted during the design and testing of new antimicrobial agents therefore, we have analysed antibacterial properties of the most active compounds towards biofilms. Our study focused on strains of Pseudomonas aeruginosa and Staphylococcus aureus that served as main model organisms for the biofilm studies.


Assuntos
Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Candida/efeitos dos fármacos , Piperidinas/química , Pirrolidinonas/isolamento & purificação , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Piperidinas/isolamento & purificação , Piperidinas/farmacologia , Pirrolidinonas/farmacologia , Relação Estrutura-Atividade
16.
J Phys Chem B ; 118(46): 13183-91, 2014 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-25340646

RESUMO

The interaction with a model membrane, the formation of DNA nanoparticles, and the transfection ability of a homologous series of bispyridinium dihexadecyl cationic gemini surfactants, differing in the length of the alkyl spacer bridging the two pyridinium polar heads in the 1 and 1' positions (P16-n with n = 3, 4, 8, 12), have been studied by means of differential scanning calorimetry (DSC), atomic force microscopy, electrophoresis mobility shift assay, and transient transfection assay measurements. The results presented here show that their performance in gene delivery is strictly related to their structure in solution. For the first time the different transfection activities of the compounds can be explained by referring to their thermodynamic properties in solution, previously studied. The compound with a spacer formed by four carbon atoms, showing unexpected enthalpic properties vs concentration in solution, is the only one giving rise to a transfection activity comparable to that of the commercial reagent, when formulated with L-α-dioleoylphosphatidylethanolamine. We suggest that P16-4 behaves like molecular tongs able to grip basic groups near each other, allowing the formation of compact and nearly spherical DNA particles. The compound with the longest spacer gives rise to loosely condensed structures by forming a sort of bow, not able to give rise to transfection notwithstanding the double positive charge of the molecule. On the other hand, DSC measurements on synthetic membranes show that the compounds with the shortest spacers (three and four methylene groups) practically do not interact with the 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine membrane, while compounds P16-8 and, particularly, P16-12 induce the formation of surfactant-rich and surfactant-poor domains in the membrane, without showing any peculiarity for compound P16-4. This could suggest that the mechanisms involved in the interaction with the model membrane and in gene delivery are substantially different and could strike a blow for an endocytosis mechanism for the internalization in the cell of the DNA nanoparticles.


Assuntos
DNA/metabolismo , Nanopartículas/química , Plasmídeos/metabolismo , Compostos de Piridínio/química , Tensoativos/química , Varredura Diferencial de Calorimetria , Linhagem Celular Tumoral , DNA/química , Ensaio de Desvio de Mobilidade Eletroforética , Humanos , Microscopia de Força Atômica , Termodinâmica , Transfecção
17.
Biophys Chem ; 180-181: 44-54, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23838623

RESUMO

New linear cationic surfactants - 2-(alkyldimethylammonio)ethylgluconamide bromides, denoted as CnGAB, n=10, 12, 14 and 16 - were synthesized from natural resources and characterized with respect to their potential as gene-delivery agents in gene therapy applications. Interactions with plasmid DNA and with model membranes were studied both experimentally and theoretically. The compounds with n=12, 14 and 16 show exponentially increasing ability to fully condense DNA. C16GAB condenses DNA at 1:1 surfactant to nucleotide molar ratio. Furthermore, CnGABs interact with model membrane, slightly lowering the temperature of the main phase transition Tm of the DPPC bilayer. C10GAB is found to interact only at the membrane surface. C16GAB reduces Tm less than C12GAB and C14GAB, and forms domains in the bilayer at the surfactant/DPPC molar ratio of 0.1 and higher. The results suggest that C16GAB can be a promising candidate for building gene-delivery carrier systems.


Assuntos
DNA/química , Gluconatos/química , Bicamadas Lipídicas/química , Tensoativos/química , 1,2-Dipalmitoilfosfatidilcolina/química , Varredura Diferencial de Calorimetria , Cátions/química , DNA/metabolismo , Bicamadas Lipídicas/metabolismo , Modelos Moleculares , Transição de Fase , Plasmídeos/química , Plasmídeos/metabolismo , Espectrometria de Fluorescência , Temperatura de Transição
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