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1.
Nucleic Acids Res ; 48(12): e67, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32421771

RESUMO

We designed and engineered a dye production cassette encoding a heterologous pathway, including human tyrosine hydroxylase and Amanita muscaria 4,5-DOPA dioxygenase, for the biosynthesis of the betaxanthin family of plant and fungal pigments in mammalian cells. The system does not impair cell viability, and can be used as a non-protein reporter system to directly visualize the dynamics of gene expression by profiling absorbance or fluorescence in the supernatant of cell cultures, as well as for fluorescence labeling of individual cells. Pigment profiling can also be multiplexed with reporter proteins such as mCherry or the human model glycoprotein SEAP (secreted alkaline phosphatase). Furthermore, absorbance measurement with a smartphone camera using standard application software enables inexpensive, low-tech reporter quantification.


Assuntos
Proteínas Fúngicas/metabolismo , Genes Reporter , Oxigenases/metabolismo , Ácidos Picolínicos/metabolismo , Análise de Célula Única/métodos , Absorção de Radiação , Animais , Células CHO , Cricetinae , Cricetulus , Proteínas Fúngicas/genética , Células HEK293 , Humanos , Microscopia de Fluorescência/métodos , Oxigenases/genética , Ácidos Picolínicos/efeitos da radiação , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Espectrometria de Fluorescência/métodos , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo , Raios Ultravioleta
3.
Chemphyschem ; 17(1): 128-35, 2016 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-26538240

RESUMO

The photophysical and nonlinear optical properties of water-soluble chromophore-functionalised tris-dipicolinate complexes [LnL3](3-) (Ln=Yb and Nd) are thoroughly studied, revealing that only the Yb(III) luminescence can be sensitized by a two-photon excitation process. The stability of the complex in water is strongly enhanced by embedding in dispersible organosilicate nanoparticles (NPs). Finally, the spectroscopic properties of [NBu4]3 [YbL3] are studied in solution and in the solid state. The high brightness of the NPs allows imaging them as single objects using a modified two-photon microscopy setup in a NIR-to-NIR configuration.


Assuntos
Complexos de Coordenação/efeitos da radiação , Microscopia Confocal/métodos , Nanopartículas/efeitos da radiação , Ácidos Picolínicos/efeitos da radiação , Itérbio/química , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Luz , Nanopartículas/química , Ácidos Picolínicos/síntese química , Ácidos Picolínicos/química , Espectroscopia de Luz Próxima ao Infravermelho
4.
Molecules ; 15(5): 2994-3009, 2010 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-20657461

RESUMO

The work describes a study of the oxidation power of N-doped and undoped anatase TiO(2), as well as TiO(2) Degussa P25 suspensions for photocatalytic degradation of the herbicides RS-2-(4-chloro-o-tolyloxy)propionic acid (mecoprop) and 3,6-dichloro-pyridine-2-carboxylic acid (clopyralid) using visible and UV light. Undoped nanostructured TiO(2) powder in the form of anatase was prepared by a sol-gel route. The synthesized TiO(2), as well as TiO(2) Degussa P25 powder, were modified with urea to introduce nitrogen into the structure. N-doped TiO(2) appeared to be somewhat more efficient than the starting TiO(2) (anatase) powder when visible light was used for mecoprop degradation. N-doped TiO(2) Degussa P25 was also slightly more efficient than TiO(2) Degussa P25. However, under the same experimental conditions, no degradation of clopyralid was observed in the presence of any of the mentioned catalysts. When the kinetics of mecoprop degradation was studied using UV light, more efficient were the undoped powders, while in the case of clopyralid, N-doped TiO(2) Degussa P25 powder was most efficient, which is probably a consequence of the difference in the molecular structure of the two herbicides.


Assuntos
Ácido 2-Metil-4-clorofenoxiacético/análogos & derivados , Herbicidas/química , Fotólise , Ácidos Picolínicos/química , Titânio/química , Ácido 2-Metil-4-clorofenoxiacético/química , Ácido 2-Metil-4-clorofenoxiacético/efeitos da radiação , Catálise , Recuperação e Remediação Ambiental/métodos , Herbicidas/efeitos da radiação , Nanoestruturas/química , Ácidos Picolínicos/efeitos da radiação , Suspensões
5.
J Hazard Mater ; 168(1): 94-101, 2009 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-19264403

RESUMO

The work is concerned with the kinetics, identification of intermediates and reaction pathways of the photocatalytic degradation of the herbicide clopyralid (3,6-dichloropyridine-2-carboxylic acid) in UV illuminated aqueous suspensions of TiO(2) (Degussa P25). In the investigated concentration range (0.5-3.0 mM) the photocatalytic degradation kinetics of clopyralid in the first stage of the reaction follows approximately a pseudo-first kinetic order. The highest reaction rate was observed at 4 mg mL(-1)of catalyst concentration, the apparent activation energy of the reaction being 7.74 kJ mol(-1). The effect of the presence of hydrogen peroxide, potassium bromate, and ammonium persulfate, acting as electron acceptors along with molecular oxygen, were also studied. By studying the effect of ethanol as a hydroxyl radical scavenger it was shown that the heterogeneous catalysis takes place mainly via hydroxyl radicals. The reaction intermediates (3,6-dichloropyridin-2-ol, 3,6-dichloro hydroxypyridine-2-carboxylic acid, and 3,3',6,6'-tetrachloro-2,4'-bipyridine-2'-carboxylic acid) were identified and the kinetics of their appearance/disappearance was followed by LC-MS/MS (ESI+). Tentative photodegradation pathways were proposed and discussed.


Assuntos
Fotólise , Ácidos Picolínicos/efeitos da radiação , Titânio/química , Catálise , Fenômenos Químicos , Poluentes Ambientais/efeitos da radiação , Herbicidas/efeitos da radiação , Radical Hidroxila/química , Cinética , Suspensões
6.
Prikl Biokhim Mikrobiol ; 42(1): 44-51, 2006.
Artigo em Russo | MEDLINE | ID: mdl-16521575

RESUMO

Degradation of Lontrel by activated sludge (AS) of purification works and UV irradiation was studied. 3,6-Dichloropicolinic acid (3,6-DCPA, the main active principle of Lontrel) was not degraded by the microbial association of the AS. AS treated with nitrosourea under various conditions did not oxidize Lontrel either. Hard UV radiation degraded 3,6-DCPA within 4-24 h at constant sparging (bubbling) of air, oxygen, or ozone. The rate of oxidation with oxygen or ozone bubbling was three to four times higher than with air bubbling. It was found that the products of photochemical degradation of Lontrel were also toxic; however, they were readily degraded by AS microorganisms without additional AS treatment.


Assuntos
Herbicidas/química , Ácidos Picolínicos/química , Raios Ultravioleta , Biodegradação Ambiental , Herbicidas/metabolismo , Herbicidas/efeitos da radiação , Oxirredução , Oxigênio/química , Ozônio/química , Fotoquímica , Ácidos Picolínicos/metabolismo , Ácidos Picolínicos/efeitos da radiação , Esgotos/química
7.
Photochem Photobiol Sci ; 5(1): 88-94, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16395432

RESUMO

The photochemistry of 6-chloro and 6-bromopicolinate ions ( and , respectively) was investigated by product studies and ns laser flash photolysis (LFP). In deoxygenated pH 5.4 water, yields 6-hydroxypicolinic acid (70%) and a substituted pyrrole. In 2-propanol-water (1 : 1) mixture, the reaction yields, very unselectively, 6-hydroxypicolinic acid, 2-carboxypyridine, pyridine and bipyridines. Photolysis of aqueous leads to 6-hydroxypicolinic acid (78%) and hydroxybipyridines. Oxygen suppresses the photolysis of but does not affect that of . By LFP, we detected a short-lived transient at the pulse end from (lambda(max)= 305 nm, k=(2.8 +/- 0.2)x 10(5) s(-1), epsilonphi= 2200 +/- 200 dm3 mol(-1) cm(-1)). This is quenched either by oxygen or methyl acrylate and thus assigned to the triplet excited state. The triplet excited state of is detected at pH 1 only (lambda(max)= 320 nm, k > 3 x 10(7) s(-1)). The radical ion Cl2- could be successfully detected by photolysing in 2-propanol-water (1 : 1) in the presence of Cl-. Similarly, Br2- could be detected by irradiating aqueous in the presence of Br-. These results show that the photodehalogenation of is heterolytic in water and mainly homolytic in 2-propanol-water mixtures while that of is both heterolytic and homolytic in water. A mechanism in which the triplet excited state undergoes homolysis of the C-X bond and subsequent electron transfer from the carboxypyridyl radical to the halogen atom to form an ion pair may account for these observations.


Assuntos
Ácidos Picolínicos/síntese química , Ácidos Picolínicos/efeitos da radiação , Ciclização , Lasers , Espectroscopia de Ressonância Magnética/métodos , Estrutura Molecular , Oxigênio/química , Fotoquímica , Fotólise , Ácidos Picolínicos/química , Sensibilidade e Especificidade , Água/química
8.
Nature ; 437(7057): 334, 2005 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-16163341

RESUMO

The way flowers appear to insects is crucial for pollination. Here we describe an internal light-filtering effect in the flowers of Mirabilis jalapa, in which the visible fluorescence emitted by one pigment, a yellow betaxanthin, is absorbed by another, a violet betacyanin, to create a contrasting fluorescent pattern on the flower's petals. This finding opens up new possibilities for pollinator perception as fluorescence has not previously been considered as a potential signal in flowers.


Assuntos
Flores/química , Flores/efeitos da radiação , Fluorescência , Nyctaginaceae/química , Nyctaginaceae/efeitos da radiação , Animais , Betacianinas , Cromatografia Líquida de Alta Pressão , Cor , Indóis/análise , Indóis/química , Indóis/isolamento & purificação , Indóis/efeitos da radiação , Insetos/fisiologia , Luz , Modelos Biológicos , Ácidos Picolínicos/análise , Ácidos Picolínicos/química , Ácidos Picolínicos/isolamento & purificação , Ácidos Picolínicos/efeitos da radiação , Pigmentação , Pigmentos Biológicos/análise , Pigmentos Biológicos/química , Pigmentos Biológicos/isolamento & purificação , Pigmentos Biológicos/efeitos da radiação , Pólen/fisiologia
9.
Appl Spectrosc ; 58(12): 1408-12, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15606952

RESUMO

Ultraviolet (UV) resonance Raman spectra of Bacillus subtilis endospores have been excited at 244 nm. Spectra can be interpreted in terms of contributions from calcium dipicolinate and nucleic acid components. Differences between spectra of spores and vegetative cells are very large and are due to the dominance of the dipicolinate features in the spore spectra. Because the DNA and RNA composition of B. subtilis spores is known and because the cross-sections of Raman bands belonging to DNA and RNA bases are known, it is possible to calculate resonance Raman spectral cross-sections for the spore Raman peaks associated with the nucleic acids. The cross-sections of peaks associated with calcium dipicolinate have been measured from aqueous solutions. Cross-section values of the dominant 1017 cm(-1) calcium dipicolinate peak measured from the Bacillus spores have been shown to be consistent with a calcium dipicolinate composition of ten percent or less by weight in the spores. It is suggested that spectral cross-sections of endospores excited at 244 nm can be estimated to be the sum of the cross-sections of the calcium dipicolinate, DNA, and RNA components of the spore. It appears that the peaks due to DNA and RNA can be used as an internal standard in the calculation of spore Raman peak cross-sections, and potentially the amount of calcium dipicolinate in spores. It is estimated on the basis of known nucleic acid base cross-sections that the most intense Raman band of the Bacillus subtilis spore spectra has a cross-section of no more than 4 x 10(-18) cm(2)/mol-sr.


Assuntos
Bacillus subtilis/isolamento & purificação , Bacillus subtilis/metabolismo , Compostos de Cálcio/metabolismo , Contagem de Colônia Microbiana/métodos , Ácidos Picolínicos/química , Análise Espectral Raman/métodos , Esporos Bacterianos/isolamento & purificação , Esporos Bacterianos/metabolismo , Bacillus subtilis/efeitos da radiação , Compostos de Cálcio/análise , Compostos de Cálcio/efeitos da radiação , Luz , Ácidos Picolínicos/análise , Ácidos Picolínicos/efeitos da radiação , Esporos Bacterianos/citologia , Esporos Bacterianos/efeitos da radiação
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