Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
J Synchrotron Radiat ; 29(Pt 2): 393-399, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35254302

RESUMO

Algorithms and procedures to fully automate retuning of synchrotron radiation beamlines over wide energy ranges are discussed. The discussion is based on the implementation at the National Institute of General Medical Sciences and the National Cancer Institute Structural Biology Facility at the Advanced Photon Source. When a user selects a new beamline energy, software synchronously controls the beamline monochromator and undulator to maintain the X-ray beam flux after the monochromator, preserves beam attenuation by determining a new set of attenuator foils, changes, as needed, mirror reflecting stripes and the undulator harmonic, preserves beam focal distance of compound refractive lens focusing by changing the In/Out combination of lenses in the transfocator, and, finally, restores beam position at the sample by on-the-fly scanning of either the Kirkpatrick-Baez mirror angles or the transfocator up/down and inboard/outboard positions. The sample is protected from radiation damage by automatically moving it out of the beam during the energy change and optimization.


Assuntos
Lentes , Síncrotrons , Fótons , Software , Raios X
2.
Appl Opt ; 59(28): 8575-8581, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33104536

RESUMO

Optimization of a wide-angle paratellurite acousto-optic tunable filter (AOTF) is performed for applications in laser beam shaping systems. The AOTF configuration with annular transfer function is analyzed. It is demonstrated that the optimal AOTF design for single-frequency operation as a narrow-band spatial frequency filter is obtained at acoustic propagation angle of 5.6° relative to the [110] axis. The optimal design for maximization of AOTF resolution in multifrequency laser beam shaping operation mode is obtained at acoustic propagation angle of 13.8°.

3.
Wiad Lek ; 73(11): 2416-2420, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33454676

RESUMO

OBJECTIVE: The aim: To determine the serum FAMG in the I and II trimester of pregnancy in women with a past history of chronic endometritis, and to clarify its impact on the development of pathology of pregnancy. PATIENTS AND METHODS: Materials and methods: The level of FAMG was determined at 6-8 and 16-18 weeks of gestation in 135 pregnant women with a past history of chronic endometritis, who received treatment of chronic endometritis at the stage of pregravid preparation and 168 women who became pregnant without its prior treatment. The dependence of the development of pre-eclampsia on the level of FAMG at the early stages of pregnancy has been evaluated. RESULTS: Results: At 6-8 weeks of pregnancy, the level of FAMG in women with a past history of chronic endometritis was 20.6% lower (122.4 ± 7.6 ng/ml) compared to the control group. In FAMG of 90.3 ± 4.3 ng/ml at 6-8 weeks of gestation, spontaneous abortion occurred in 100% of cases within the next 2 weeks. FAMG lower than 122,1 ± 3,0 ng/ml can be the predisposing factor for the development of pre-eclampsia. CONCLUSION: Conclusions: Reduced FAMG in the beginning of pregnancy in women with untreated chronic endometritis in the past history increases the incidence of miscarriages at the early stages by 2.6 times, and by 1.8 times the probability of preeclampsia development. Treatment of chronic endometritis at the stage of pregravid preparation promotes the increase of FAMG by 24,6% compared to untreated women that reduces the probability of complications during the subsequent course of pregnancy.


Assuntos
Aborto Espontâneo , Endometrite , Pré-Eclâmpsia , Decídua , Feminino , Humanos , Gravidez , Primeiro Trimestre da Gravidez , Gestantes
4.
Opt Lett ; 44(6): 1500-1503, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30874686

RESUMO

A new protocol of hyperspectral data acquisition with an acousto-optical tunable filter is proposed and tested experimentally. Correction for the illumination source spectrum and regular spectral sensitivity factors is embedded in the data acquisition routine. The protocol is based on the adaptive electronic setting of the filter transmission passband inversely proportional to the power spectrum of the light source. Spectral equalization of the light source spectrum in a hyperspectral imaging spectrometer is demonstrated with 3% standard deviation over the bandwidth 465-820 nm. The broadening of the point-spread function does not exceed 20% at fourfold bandwidth extension owing to a confocal configuration of the spectrometer.

5.
Wiad Lek ; 72(1): 64-67, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30796864

RESUMO

OBJECTIVE: Introduction: Detection and treatment of chronic endometritis (CE) is clinically significant, though involves intrauterine intervention to collect endometrium. The aim: To estimate the possibility to use fertility α2-microglobulin (FAMG) as the marker of the high risk for CE. PATIENTS AND METHODS: Materials and methods: 70 women with CE who were planning pregnancy were tested for FAMG in menstrual blood. 40 of them received treatment of CE. The other 30 women refused from the proposed treatment. The control group involved 30 women who had neither CE nor luteal phase deficiency (LPD). Additional group (20 women) had LPD without CE. RESULTS: Results: The decrease of FAMG by 2.4 times was noted in women with CE (16.3 ± 3.9 µg/ml against 39.8 ± 8.3 µg/ml in the controls). In LPD the index was 5.6 times lower. After treatment the level of FAMG was increasing. CONCLUSION: Conclusions: The decrease of the amount of FAMG in menstrual blood is specific for women both with CE and LPD. Detection of abnormally low rates of FAMG in all women with CE enables, with the exception of absolute hypoprogesteronemia and LPD, using it as a simple method of estimation of the functional state of endometrium. Its application can be very useful both for non-invasive diagnosis of CE and subsequent evaluation of treatment of this pathology.


Assuntos
alfa-Globulinas/análise , Endometrite/diagnóstico , Estudos de Casos e Controles , Doença Crônica , Endométrio/patologia , Feminino , Humanos , Infertilidade Feminina , Fase Luteal , Gravidez
6.
Wiad Lek ; 71(8): 1550-1553, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30684339

RESUMO

OBJECTIVE: Introduction: The frequency of the pathological course of pregnancy with hyperandrogenism ranges from 21 to 48%. With the predominance of androgens against the background of lowering the normal products of steroidogenesis, a pro-inflammatory immune imbalance is formed, which causes a premature termination of the development of pregnancy. Many studies indicate that hyperandrogenism is a factor in the development of obstetric pathology, including placental dysfunction. The severity of obstetric complications of pregnancy in women with hyperandrogenism depends on the duration of the disease and the quality of preparation for pregnancy. Establishing early markers of endocrine hyperandrogenic imbalance in the body of a future mother and conducting timely therapy is the key to the successful completion of pregnancy. The aim: the establishment of hormonal-immunological changes and morphological and receptive structure peculiarities of the endometrium correlations in women with PCOS at the pregnancy planning stage. PATIENTS AND METHODS: Materials and methods: 139 women with PCOS were screened at the stage of pregnancy planning. Diagnosis of PCI was conducted in accordance with the International Recommendations of Endocrine Society 2013 and the Rotterdam criteria of 2003. Endometrial aspiration was studied for the study of T and B lymphocyte populations, cytokine levels and endometrial receptors. Hormonal parameters were determined using the radioimmunological method using Immunotech (Czech Republic) and Siena Ire Sorin (France) kits. Normal values of the studied hormones in accordance with the recommendations of the manufacturer. In order to study the populations of T and B lymphocytes and endometrial receptors the aspirate, obtained by endometrial biopsies, was used taken on the 5-7 and 21-24 days of the menstrual cycle. The cytokines levels (INF-y, TNF-a, Il-4, Il-6, Il-8, Il-10) were estimated in the endometrium with the help of the test system "Protein contour" on immunoenzymatic analyzer "Multyskan EX" (Germany). The assessment of estrogens receptors at stroma and glands and progesterone receptors at stroma and glands was performed by H -Score system, lymphocytes count was carried out by the light microscope at 400 x 3 fields-of-view expansion. Statistical material analysis was carried out on the personal computer using the standard software package with applied statistical analysis (Excel 2003 and Statistica v. 6.0). The assessment of variables connection was carried out by Pirson's coefficient correlations. The statistical significance of differences was performed by the use of nonparametric Mann -Whitney criteria, χ2 and Fisher criterium. The significance threshold of statistical value was considered p = 0.05. RESULTS: Results: In women with hyperandrogenism, there was a significant increase (p <0.05) in the level of DHEA-S, a decrease in the level of E2 and progesterone in the early follicular phase compared with the control group and an increase in body weight by 37.5%. At histological examination of the endometrium on the 5-7th day of the menstrual cycle there was a lag proliferative changes of the endometrium, and in one third of women hyperplastic process against the background of reduced proliferative activity. At GA there was a marked violation of expression of receptors as estrogens and progesterone stroma in all stages of the menstrual cycle. In women with hyperandrogenism, changes in the immunological profile of endometriosis with the prevalence of Th-1 orientation of immunity have been detected. CONCLUSION: Conclusions: In women with hyperandrogenism there is a close correlation between the biochemical form of the domination of androgens, ovulatory dysfunction, immunohistochemical and morphological structure of the endometrium. Revealed features of pro-inflammatory direction of cytokine immunity.


Assuntos
Endométrio/patologia , Hiperandrogenismo/patologia , Síndrome do Ovário Policístico/patologia , Citocinas/análise , Feminino , Hormônios/análise , Humanos , Gravidez , Receptores de Estrogênio/análise , Receptores de Progesterona/análise , Fatores de Risco
7.
Wiad Lek ; 71(9): 1719-1721, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30737929

RESUMO

OBJECTIVE: Introduction: Chronic endometritis (CE) associated lesions lessen the implantation potential of endometrium and aggravate the course of invasive processes in the uterine vessels The aim: Study of changes in doplerometric parameters of blood flow in spiral and uterine arteries in 17-18 weeks of pregnancy in women with СE in anamnesis. PATIENTS AND METHODS: Materials and methods: Сalculation of systolic/diastolic ratio (SDR), pulse index (PI) and resistive index (RI) has been carried out in 70 pregnant had CE in past history and 10 healthy pregnant women who experienced neither chronic endometritis before pregnancy nor preeclampsia. RESULTS: Results: SDR in SA patients with CE in history and follow-up development of preeclampsia is by 19& higher the control values (р<0,05); PI was 85& higher than the similar one in the control group and RI was 86& higher (р<0,01). In women with a preconception preparation that had a subsequent development of preeclampsia SDR in the spiral artery by 9,7& (p <0,05), PI by 31,7&, and IR by 30,3& (p <0,05) was lower than the corresponding indices in the group of untreated women. CONCLUSION: Conclusions: The findings show the increase in resistance of preplacental bed vessels in women with untreated CE in past history at the aforementioned stage, and the more apparent are the curves of blood flow rate at this stage, the more severe will be the follow-up course of preeclampsia.


Assuntos
Pré-Eclâmpsia/fisiopatologia , Artéria Uterina/fisiopatologia , Útero/irrigação sanguínea , Velocidade do Fluxo Sanguíneo , Estudos de Casos e Controles , Feminino , Humanos , Gravidez , Ultrassonografia Pré-Natal
8.
Proc Natl Acad Sci U S A ; 108(15): 6127-32, 2011 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-21444772

RESUMO

Radiation damage is a major limitation in crystallography of biological macromolecules, even for cryocooled samples, and is particularly acute in microdiffraction. For the X-ray energies most commonly used for protein crystallography at synchrotron sources, photoelectrons are the predominant source of radiation damage. If the beam size is small relative to the photoelectron path length, then the photoelectron may escape the beam footprint, resulting in less damage in the illuminated volume. Thus, it may be possible to exploit this phenomenon to reduce radiation-induced damage during data measurement for techniques such as diffraction, spectroscopy, and imaging that use X-rays to probe both crystalline and noncrystalline biological samples. In a systematic and direct experimental demonstration of reduced radiation damage in protein crystals with small beams, damage was measured as a function of micron-sized X-ray beams of decreasing dimensions. The damage rate normalized for dose was reduced by a factor of three from the largest (15.6 µm) to the smallest (0.84 µm) X-ray beam used. Radiation-induced damage to protein crystals was also mapped parallel and perpendicular to the polarization direction of an incident 1-µm X-ray beam. Damage was greatest at the beam center and decreased monotonically to zero at a distance of about 4 µm, establishing the range of photoelectrons. The observed damage is less anisotropic than photoelectron emission probability, consistent with photoelectron trajectory simulations. These experimental results provide the basis for data collection protocols to mitigate with micron-sized X-ray beams the effects of radiation damage.


Assuntos
Cristalografia por Raios X , Proteínas/química , Proteínas/efeitos da radiação , Anisotropia , Cristalografia por Raios X/estatística & dados numéricos , Método de Monte Carlo
9.
Biodegradation ; 25(6): 787-95, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25052918

RESUMO

The biodegradation of the polycyclic aromatic hydrocarbon phenantherene by the rhizobacterial strain Ensifer meliloti P221, isolated from the root zone of plant grown in PAH-contaminated soil was studied. Bacterial growth and phenanthrene degradation under the influence of root-exuded organic acids were also investigated. Analysis of the metabolites produced by the strain by using thin-layer chromatography, gas chromatography, high-pressure liquid chromatography, and mass-spectrometry revealed that phenanthrene is bioconverted via two parallel pathways. The first, major pathway is through terminal aromatic ring cleavage (presumably at the C3-C4 bond) producing benzocoumarin and 1-hydroxy-2-naphthoic acid, whose further degradation with the formation of salicylic acid is difficult or is very slow. The second pathway is through the oxidation of the central aromatic ring at the C9-C10 bond, producing 9,10-dihydro-9,10-dihydroxyphenanthrene, 9,10-phenanthrenequinone, and 2,2'-diphenic acid. This is the first time that the dioxygenation of phenanthrene at the C9 and C10 atoms, proven by identification of characteristic metabolites, has been reported for a bacterium of the Ensifer genus.


Assuntos
Biodegradação Ambiental , Fenantrenos/metabolismo , Rhizobium/metabolismo , Compostos de Bifenilo/metabolismo , Naftóis/metabolismo
10.
J Synchrotron Radiat ; 20(Pt 4): 531-40, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23765294

RESUMO

Nonlinear optical (NLO) instrumentation has been integrated with synchrotron X-ray diffraction (XRD) for combined single-platform analysis, initially targeting applications for automated crystal centering. Second-harmonic-generation microscopy and two-photon-excited ultraviolet fluorescence microscopy were evaluated for crystal detection and assessed by X-ray raster scanning. Two optical designs were constructed and characterized; one positioned downstream of the sample and one integrated into the upstream optical path of the diffractometer. Both instruments enabled protein crystal identification with integration times between 80 and 150 µs per pixel, representing a ∼10(3)-10(4)-fold reduction in the per-pixel exposure time relative to X-ray raster scanning. Quantitative centering and analysis of phenylalanine hydroxylase from Chromobacterium violaceum cPAH, Trichinella spiralis deubiquitinating enzyme TsUCH37, human κ-opioid receptor complex kOR-T4L produced in lipidic cubic phase (LCP), intimin prepared in LCP, and α-cellulose samples were performed by collecting multiple NLO images. The crystalline samples were characterized by single-crystal diffraction patterns, while α-cellulose was characterized by fiber diffraction. Good agreement was observed between the sample positions identified by NLO and XRD raster measurements for all samples studied.


Assuntos
Microscopia de Fluorescência/métodos , Síncrotrons , Cristalização , Humanos , Proteínas/química , Difração de Raios X
11.
Artigo em Inglês | MEDLINE | ID: mdl-25383086

RESUMO

GM/CA at the APS has developed microcrystallography capabilities for structural biology applications. The robust, quad, mini-beam collimators, which enable users to rapidly select between a 5, 10 or 20 micron diameter beam or a scatter guard for the full focused beam, are coupled with several powerful automated software tools that are built into the beamline control system JBluIce-EPICS. Recent successes at beamlines around the world in solving structures from microcrystals (2 - 10 microns) have led to increased demand for high-intensity micro-focus beams. We have designed a new micro-focus endstation to increase the intensity in mini- and micro-beams at GM/CA by one to two orders of magnitude to meet this growing demand. The new optical design is based on the well-established approach of using two-stage demagnification. The existing bimorph mirrors, arranged in a Kirkpatrick-Baez geometry, focus the beam onto slits located upstream of the sample whereby the slit aperture defines a secondary source, that is reimaged with a second pair of mirrors. This design incorporates two focal modes: a mini-beam mode where the beam is focused to 20-micron diameter and a micro-beam mode where it is focused to 5-microns. The size of the secondary source aperture can be varied rapidly (seconds) to adjust the beam size at the sample position in two ranges 20 - 3 micron and 5 - 1 micron. The second set of mirrors will each have two super polished ellipses allowing quick (minutes) interchange between modes.

12.
Acta Crystallogr D Biol Crystallogr ; 67(Pt 3): 176-88, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21358048

RESUMO

The trio of macromolecular crystallography beamlines constructed by the General Medicine and Cancer Institutes Collaborative Access Team (GM/CA-CAT) in Sector 23 of the Advanced Photon Source (APS) have been in growing demand owing to their outstanding beam quality and capacity to measure data from crystals of only a few micrometres in size. To take full advantage of the state-of-the-art mechanical and optical design of these beamlines, a significant effort has been devoted to designing fast, convenient, intuitive and robust beamline controls that could easily accommodate new beamline developments. The GM/CA-CAT beamline controls are based on the power of EPICS for distributed hardware control, the rich Java graphical user interface of Eclipse RCP and the task-oriented philosophy as well as the look and feel of the successful SSRL BluIce graphical user interface for crystallography. These beamline controls feature a minimum number of software layers, the wide use of plug-ins that can be written in any language and unified motion controls that allow on-the-fly scanning and optimization of any beamline component. This paper describes the ways in which BluIce was combined with EPICS and converted into the Java-based JBluIce, discusses the solutions aimed at streamlining and speeding up operations and gives an overview of the tools that are provided by this new open-source control system for facilitating crystallographic experiments, especially in the field of microcrystallography.


Assuntos
Cristalografia por Raios X/métodos , Cristalografia por Raios X/instrumentação , Software
13.
J Synchrotron Radiat ; 18(Pt 5): 717-22, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21862850

RESUMO

Automated scanning capabilities have been added to the data acquisition software, JBluIce-EPICS, at the National Institute of General Medical Sciences and the National Cancer Institute Collaborative Access Team (GM/CA CAT) at the Advanced Photon Source. A `raster' feature enables sample centering via diffraction scanning over two-dimensional grids of simple rectangular or complex polygonal shape. The feature is used to locate crystals that are optically invisible owing to their small size or are visually obfuscated owing to properties of the sample mount. The raster feature is also used to identify the best-diffracting regions of large inhomogeneous crystals. Low-dose diffraction images taken at grid positions are automatically processed in real time to provide a quick quality ranking of potential data-collection sites. A `vector collect' feature mitigates the effects of radiation damage by scanning the sample along a user-defined three-dimensional vector during data collection to maximize the use of the crystal volume and the quality of the collected data. These features are integrated into the JBluIce-EPICS data acquisition software developed at GM/CA CAT where they are used in combination with a robust mini-beam of rapidly changeable diameter from 5 µm to 20 µm. The powerful software-hardware combination is being applied to challenging problems in structural biology.


Assuntos
Automação Laboratorial/métodos , Cristalografia por Raios X/métodos , Substâncias Macromoleculares/efeitos da radiação , Algoritmos , Substâncias Macromoleculares/química , Software , Síncrotrons , Difração de Raios X/métodos
14.
Biomed Opt Express ; 11(12): 7053-7061, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33408979

RESUMO

Phase imaging microscopy with incoherent object illumination is convenient and affordable for biomedical research and clinics since it provides easy integration with a variety of bright-field optical microscopes. We report the design of a new hyperspectral imaging system based on a combination of a spatial light modulator (SLM) and an acousto-optic tunable filter (AOTF) for phase imaging microscopy. Contrast of phase-only objects originates from matched spectral and spatial filtering performed by the SLM and the AOTF located in Fourier-conjugate optical planes in the back-end of the optical system. The system is designed as an add-on to a standard optical microscope with incoherent diascopic sample illumination.

15.
Artigo em Inglês | MEDLINE | ID: mdl-31841406

RESUMO

A numerical method for providing linear phase response of bulk acoustic wave (BAW) piezoelectric transducers (PTs) of acousto-optic devices is developed. Our approach is based on the analytic approximation of the phase response of the PT with the matching electrical circuit and optimization with a differential evolution genetic algorithm. Simulations and experiments were performed for two typical BAW excitation schemes: direct and reflective. Variance of the group delay in the specified frequency range was reduced by an order of magnitude for reflective excitation of BAWs.

16.
Appl Opt ; 48(7): C118-24, 2009 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-19252604

RESUMO

We discuss the theoretical and experimental investigation of acousto-optic dispersive tunable filters, based on quasi-collinear geometry of light-sound interaction in a tellurium dioxide single crystal. The geometry uses the effect of strong acoustic anisotropy in the paratellurite as well as peculiarities of acoustic wave reflections at the free boundary of the crystal. A mathematical concept for determination of optical, electrical, and constructional parameters of the filters is developed. Different experimental acousto-optic filters intended for femtosecond pulse shaping are designed and tested. Preliminary experiments are performed in a subpetawatt optical parametric chirped pulse amplification laser system. The experimental data conform completely with the predicted data.

17.
Fungal Biol ; 122(5): 363-372, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29665962

RESUMO

The degradation of two isomeric three-ringed polycyclic aromatic hydrocarbons by the white rot fungus Pleurotus ostreatus D1 and the litter-decomposing fungus Agaricus bisporus F-8 was studied. Despite some differences, the degradation of phenanthrene and anthracene followed the same scheme, forming quinone metabolites at the first stage. The further fate of these metabolites was determined by the composition of the ligninolytic enzyme complexes of the fungi. The quinone metabolites of phenanthrene and anthracene produced in the presence of only laccase were observed to accumulate, whereas those formed in presence of laccase and versatile peroxidase were metabolized further to form products that were further included in basal metabolism (e.g. phthalic acid). Laccase can catalyze the initial attack on the PAH molecule, which leads to the formation of quinones, and that peroxidase ensures their further oxidation, which eventually leads to PAH mineralization. A. bisporus, which produced only laccase, metabolized phenanthrene and anthracene to give the corresponding quinones as the dominant metabolites. No products of further utilization of these compounds were detected. Thus, the fungi's affiliation with different ecophysiological groups and their cultivation conditions affect the composition and dynamics of production of the ligninolytic enzyme complex and the completeness of PAH utilization.


Assuntos
Agaricus/metabolismo , Pleurotus/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Biotransformação , Redes e Vias Metabólicas , Oxirredutases/metabolismo , Quinonas/metabolismo , Microbiologia do Solo , Madeira/microbiologia
18.
Nat Protoc ; 13(2): 260-292, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29300389

RESUMO

Protein crystallography has significantly advanced in recent years, with in situ data collection, in which crystals are placed in the X-ray beam within their growth medium, being a major point of focus. In situ methods eliminate the need to harvest crystals, a previously unavoidable drawback, particularly for often small membrane-protein crystals. Here, we present a protocol for the high-throughput in situ X-ray screening of and data collection from soluble and membrane-protein crystals at room temperature (20-25°C) and under cryogenic conditions. The Mylar in situ method uses Mylar-based film sandwich plates that are inexpensive, easy to make, and compatible with automated imaging, and that show very low background scattering. They support crystallization in microbatch and vapor-diffusion modes, as well as in lipidic cubic phases (LCPs). A set of 3D-printed holders for differently sized patches of Mylar sandwich films makes the method robust and versatile, allows for storage and shipping of crystals, and enables automated mounting at synchrotrons, as well as goniometer-based screening and data collection. The protocol covers preparation of in situ plates and setup of crystallization trials; 3D printing and assembly of holders; opening of plates, isolation of film patches containing crystals, and loading them onto holders; basic screening and data-collection guidelines; and unloading of holders, as well as reuse and recycling of them. In situ plates are prepared and assembled in 1 h; holders are 3D-printed and assembled in ≤90 min; and an in situ plate is opened, and a film patch containing crystals is isolated and loaded onto a holder in 5 min.


Assuntos
Cristalografia por Raios X/métodos , Ensaios de Triagem em Larga Escala/métodos , Cristalização , Coleta de Dados , Ensaios de Triagem em Larga Escala/instrumentação , Lipídeos , Proteínas de Membrana/análise , Polietilenotereftalatos/química , Proteínas/química , Temperatura , Raios X
19.
J Chromatogr A ; 1132(1-2): 248-55, 2006 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-16919650

RESUMO

The GLC method for determining the intramolecular hydrogen bond (intra-HB) energy as the difference between the heats of dissolution of two isomers, one of which forms an intra-HB and the other has no such bond for steric reasons, in a polar stationary liquid phase was further considered by taking account of a correction for the difference between the energies of nonspecific interactions of the isomers with a polar phase. With 4- and 2-substituted phenols as an example, the differences between their heats of dissolution in polyethylene glycol and in poly-1,4-butanediol succinate were measured. As a first approximation, corrections for the contribution of the energy of nonspecific interactions with a liquid phase to the total magnitude of the difference between the heats of isomer dissolution were found. These corrections were determined as the difference between the heats of dissolution for 1,4- and 1,2-disubstituted benzene derivatives--analogs of the compounds under study that either do not have hydroxyl groups altogether or, in the case of 1,2-isomers with a hydroxyl group, cannot form an intra-HB. On the basis of the obtained results, the average intra-HB energies of 2-fluoro- (1), 2-chloro- (2), 2-bromo- (3), 2-iodo- (4), 2-methoxyphenol (5), salicylaldehyde (6), methyl ether of salicylic acid (7) and 2-nitrophenol (8) were estimated to be 7.4+/-0.3, 13.3+/-0.8, 14.4+/-0.4, 12.8+/-0.3, 17.6+/-0.1, 24.6+/-1.2, 29.8+/-0.3 and 32.5+/-4.7 kJ/mol, respectively. The values were compared with those found in the literature.


Assuntos
Cromatografia Gasosa/métodos , Cromatografia Líquida/métodos , Fenóis/química , Ligação de Hidrogênio , Estrutura Molecular
20.
Microbiol Res ; 169(1): 99-105, 2014 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-23545355

RESUMO

Plant-growth-promoting rhizobacteria exert beneficial effects on plants through their capacity for nitrogen fixation, phytohormone production, phosphate solubilization, and improvement of the water and mineral status of plants. We suggested that these bacteria may also have the potential to express degradative activity toward glyphosate, a commonly used organophosphorus herbicide. In this study, 10 strains resistant to a 10 mM concentration of glyphosate were isolated from the rhizoplane of various plants. Five of these strains--Alcaligenes sp. K1, Comamonas sp. K4, Azomonas sp. K5, Pseudomonas sp. K3, and Enterobacter cloacae K7--possessed a number of associative traits, including fixation of atmospheric nitrogen, solubilization of phosphates, and synthesis of the phytohormone indole-3-acetic acid. One strain, E. cloacae K7, could utilize glyphosate as a source of P. Gas-liquid chromatography showed that E. cloacae growth correlated with a decline in herbicide content in the culture medium (40% of the initial 5mM content), with no glyphosate accumulating inside the cells. Thin-layer chromatography analysis of the intermediate metabolites of glyphosate degradation found that E. cloacae K7 had a C-P lyase activity and degraded glyphosate to give sarcosine, which was then oxidized to glycine. In addition, strain K7 colonized the roots of common sunflower (Helianthus annuus L.) and sugar sorghum (Sorghum saccharatum Pers.), promoting the growth and development of sunflower seedlings. Our findings extend current knowledge of glyphosate-degrading rhizosphere bacteria and may be useful for developing a biotechnology for the cleanup and restoration of glyphosate-polluted soils.


Assuntos
Enterobacter cloacae/isolamento & purificação , Enterobacter cloacae/metabolismo , Glicina/análogos & derivados , Herbicidas/metabolismo , Rizosfera , Microbiologia do Solo , Biotransformação , Cromatografia Gasosa , Cromatografia Líquida , Cromatografia em Camada Fina , Enterobacter cloacae/classificação , Enterobacter cloacae/genética , Glicina/metabolismo , Helianthus/crescimento & desenvolvimento , Helianthus/microbiologia , Fósforo/metabolismo , Raízes de Plantas/microbiologia , Sarcosina/metabolismo , Sorghum/microbiologia , Glifosato
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA