Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 105
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
J Racial Ethn Health Disparities ; 9(2): 566-575, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33566333

RESUMEN

PURPOSE: Recognizing that spiritual and religious beliefs are personal and vary within communities, the purpose of this qualitative study was to explore the influence of these beliefs on experiences with breast cancer care and social support among African American Christian breast cancer survivors. METHODS: Forty-seven African American breast cancer survivors participated in focus groups (n = 7) in three northeastern urban cities. We used thematic analyses to identify major themes. RESULTS: Three themes emerged relating to how spirituality influenced participants' cancer journeys: (1) struggling with God, (2) reclaiming my power, and (3) needing religious social support. Participants described the rhythmic flow of their spiritual beliefs as they navigated their lived experiences during diagnosis, treatment, and post-treatment. Spirituality was intimately intertwined with their illness experience as they grappled with their health and well-being. CONCLUSIONS: Participants used spirituality as an avenue to cope and navigate through their diagnosis and treatment. These spiritual relationships created "church families" and provided the survivors' access to cancer support groups, financial support, and therapeutic support. Our findings support faith-based approaches to health promotion and call for more studies to understand the influence of religion on health.


Asunto(s)
Neoplasias de la Mama , Supervivientes de Cáncer , Adaptación Psicológica , Negro o Afroamericano , Neoplasias de la Mama/terapia , Cristianismo , Femenino , Humanos , Espiritualidad , Sobrevivientes
2.
NMR Biomed ; 21(4): 357-65, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-17691080

RESUMEN

Raised concentrations of glucose for extended periods of time have detrimental effects on the insulin-producing beta-cell. As de novo synthesis of lipids has been observed under such conditions, it was hypothesized that newly formed lipids may preferentially contain saturated fatty acids, which in particular have been associated with impaired beta-cell function. Glucose-induced de novo synthesis of fatty acids in INS-1E cells cultured in 5.5, 11, 20 or 27 mM glucose for 5 days was assessed by high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy and gas chromatography-mass spectrometry (GC-MS). The glucose origin of the increase in fatty acyls was verified by replacing glucose with [1-13C]glucose during culture followed by analysis with two-dimensional 1H-13C NMR spectroscopy. The composition of the fatty acyls was determined by GC-MS. Fatty acyls determined by HR-MAS (1)H NMR spectroscopy were increased fivefold in INS-1E cells cultured in 20 or 27 mM glucose compared with cells cultured in 5.5 mM glucose. The five most abundant fatty acids with their relative percentages in INS-1E cells cultured in 5.5 mM glucose were oleate (33%), palmitate (25%), stearate (19%), octadecenoate (13%) and palmitoleate (4.4%). These proportions were not affected by glucose- induced de novo synthesis in INS-1E cells cultured in 11, 20 or 27 mM glucose. It is concluded that glucose-induced de novo lipid synthesis results in accumulation of both saturated and unsaturated fatty acids in specific proportions that are identical with those present under control conditions.


Asunto(s)
Ácidos Grasos/biosíntesis , Glucosa/farmacología , Animales , Línea Celular , Cromatografía de Gases y Espectrometría de Masas , Espectroscopía de Resonancia Magnética , Fosfatidilcolinas/análisis
3.
Appl Microbiol Biotechnol ; 64(3): 403-9, 2004 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-14600792

RESUMEN

The biocontrol yeast Pichia anomala J121 prevents mould growth during the storage of moist grain under low oxygen/high carbon dioxide conditions. Growth and metabolite formation of P. anomala was analyzed under two conditions of oxygen limitation: (a) initial aerobic conditions with restricted oxygen access during the growth period and (b) initial microaerobic conditions followed by anaerobiosis. Major intra- and extracellular metabolites were analyzed by high-resolution magic-angle spinning (HR-MAS) NMR and HPLC, respectively. HR-MAS NMR allows the analysis of major soluble compounds inside intact cells, without the need for an extraction step. Biomass production was higher in treatment (A), whereas the specific ethanol production rate during growth on glucose was similar in both treatments. This implies that oxygen availability affected the respiration and not the fermentation of the yeast. Following glucose depletion, ethanol was oxidized to acetate in treatment (A), but continued to be produced in (B). Arabitol accumulated in the culture substrate of both treatments, whereas glycerol only accumulated in treatment (B). Trehalose, arabitol, and glycerol accumulated inside the cells in both treatments. The levels of these metabolites were generally significantly higher in treatment (B) than in (A), indicating their importance for P. anomala during severe oxygen limitation/anaerobic conditions.


Asunto(s)
Oxígeno/metabolismo , Pichia/metabolismo , Acetatos/metabolismo , Aerobiosis , Anaerobiosis , Biomasa , Dióxido de Carbono/metabolismo , Cromatografía Líquida de Alta Presión , Etanol/metabolismo , Fermentación , Glucosa/metabolismo , Glicerol/metabolismo , Espectroscopía de Resonancia Magnética , Oxidación-Reducción , Consumo de Oxígeno , Pichia/química , Pichia/crecimiento & desarrollo , Alcoholes del Azúcar/metabolismo , Trehalosa/metabolismo
4.
Carbohydr Res ; 336(4): 291-6, 2001 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-11728397

RESUMEN

Chitosans with chemical composition ranging from a fraction of N-acetylated units (F(A)) of 0.01 to 0.61 were used to prepare fluorescence labelled chitosans by reductive amination with 9-anthraldehyde. Fluorescent chitosans with a low theoretical degree of substitution (DS, 0.001-1%) were prepared, and the actual DS of the products were determined by UV and (1)H NMR spectroscopy. The fluorescence excitation and emission spectra of the chitosan with F(A) of 0.09 and DS 1% showed an excitation maximum at 254 nm and an emission maximum at 413 nm. The intrinsic viscosities ([eta]) of the fluorescent chitosans were compared to those of the original chitosans, showing that the derivatisation procedure lead only to a negligible decrease in [eta]. The conformation of these fluorescent chitosans with very low DS-values is not altered and they can conveniently be directly quantified by UV or fluorescence spectroscopy.


Asunto(s)
Antracenos/química , Quitina/síntesis química , Colorantes Fluorescentes/síntesis química , Acetilación , Calibración , Quitina/análogos & derivados , Quitina/química , Quitosano , Colorantes Fluorescentes/química , Espectroscopía de Resonancia Magnética , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta , Análisis Espectral , Viscosidad
5.
Carbohydr Res ; 336(4): 319-23, 2001 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-11728401

RESUMEN

The hydroxy protons of the disaccharide moiety in the glycopeptide Val-[beta-Gal(1-->3)-alpha-GalNAc(1-->O)]-Thr-His-Pro-Gly-Tyr (1) have been investigated in aqueous solution using (1)H NMR spectroscopy. The chemical shifts (delta), coupling constants ((3)J(CH,OH)), temperature coefficients (d delta/dT), exchange rates (k(ex)), and NOEs have been measured. The data show that the O(2')H of Gal has a reduced contact with water due to steric interference caused by the 2-acetamido group of GalNAc. No interaction, in terms of hydrogen bonding exists between the disaccharide and the peptide moieties, but the rotation around the sugar-peptide linkage is restricted.


Asunto(s)
Glicopéptidos/química , Espectroscopía de Resonancia Magnética , Disacáridos/química , Fibronectinas/química , Humanos , Conformación Molecular , Fragmentos de Péptidos/química , Protones , Temperatura , Agua/química
6.
Carbohydr Res ; 329(4): 817-29, 2000 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-11125824

RESUMEN

Six novel fucose 3-O-acetylated saponins, with a quillaic acid aglycone, were isolated from a bark extract from the Quillaja saponaria Molina tree. In addition, a saponin with a novel aglycone (phytolaccagenic acid) and a novel fatty acyl group [(S)-2-methylbutanoyl] for Quillaja saponins was found. The compounds were characterised using NMR spectroscopy, mass spectrometry and chemical methods.


Asunto(s)
Ácido Oleanólico/análogos & derivados , Rosales/química , Saponinas/química , Saponinas/aislamiento & purificación , Acetilación , Secuencia de Carbohidratos , Cromatografía Líquida de Alta Presión , Fucosa/química , Espectroscopía de Resonancia Magnética , Datos de Secuencia Molecular , Estructura Molecular , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Terpenos/química
7.
Carbohydr Res ; 329(2): 257-68, 2000 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-11117310

RESUMEN

Lactones of methyl 3-O-[(R)- and (S)-1-carboxyethyl]-alpha-D-gluco-, galacto- and manno-pyranoside were prepared by treatment of the sugar derivatives in acetic acid. The lactones were formed between the 1-carboxyethyl substituent and 2-OH or 4-OH in different proportions depending on the stereochemistry of the parent compounds. Relative formation rates in acetic acid-d4 and hydrolysis rates in buffered D2O solutions at pD 2.4, 4.6 and 7.4 were estimated. Hydrolysis of the formed lactones is relatively slow in D2O at pD 4.6, which permitted characterization of the lactones by 1H and 13C NMR spectroscopy in buffered D2O solutions. Hydrolysis of the lactones in 1 M aqueous NaOH at 80 degrees C gave no detectable isomerization of the alpha-carbon. The set of lactones formed from the 1-carboxyethyl substituted methyl glycosides used in this study showed large similarities in the NMR shifts (delta delta values). Deviations from the observed shift pattern were found for two lactones. Our findings strongly suggest that those two lactones differ from the rest by adopting a boat-like conformation, whereas the others adopt pseudo-chair conformations.


Asunto(s)
Lactonas/química , Ácido Acético , Conformación de Carbohidratos , Óxido de Deuterio , Galactósidos/química , Glucósidos/química , Hidrólisis , Lactonas/síntesis química , Espectroscopía de Resonancia Magnética , Manósidos/química , Solventes , Estereoisomerismo
8.
Carbohydr Res ; 328(3): 409-18, 2000 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-11072848

RESUMEN

The 1H NMR chemical shifts, vicinal coupling constants, temperature coefficients, and exchange rates of the hydroxy protons of a Lewis b tetrasaccharide derivative, alpha-L-Fucp-(1 --> 2)-beta-D-Galp-(1 --> 3)[alpha-L-Fucp-(1 --> 4)]-beta-D-GlcpNAc-1-O(CH2)2NHCOCHCH2, have been measured in aqueous solution. The data did not show any evidence for persistent hydrogen bonds participating in the stabilization of the structure. While most of the hydroxy proton signals have chemical shifts similar to those of the corresponding methyl glycosides, four of them, O(3)H, O(4)H, and O(6)H of Galp, and O(2)H of the Fucp linked to GlcpNAc, exhibit large upfield shifts. This shielding effect has been attributed to the orientation of the hydroxy protons toward the amphiphilic region constituted by the hydroxy groups of the Galp residue and mainly the ring and methyl hydrogens of the Fucp unit attached to the GlcpNAc. The close face to face stacking interaction between the Fucp linked to the GlcpNAc and the Galp residues, as well as the steric interaction between the Fucp linked to the Galp and the GlcpNAc are confirmed by the additional inter-residue NOEs of the exchangeable protons in sugar units which are not directly connected.


Asunto(s)
Espectroscopía de Resonancia Magnética , Oligosacáridos/química , Protones , Conformación de Carbohidratos , Secuencia de Carbohidratos , Antígenos del Grupo Sanguíneo de Lewis , Datos de Secuencia Molecular , Estructura Molecular , Agua/química
9.
Anal Biochem ; 284(2): 367-74, 2000 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-10964421

RESUMEN

The use of high-resolution magic angle spinning NMR spectroscopy for in situ studies of low-molecular-mass compounds in red algae has been studied. The impact of different acquisition parameters on the resulting T(2)-filtered one-dimensional high-resolution magic angle spinning (1)H NMR spectra is described. The technique was used for in situ identification and quantification of some low-molecular-mass algal metabolites.


Asunto(s)
Espectroscopía de Resonancia Magnética/métodos , Rhodophyta/química , Peso Molecular
10.
Phytochemistry ; 54(6): 615-23, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10963456

RESUMEN

Sixteen saponins were identified from a bark extract of Quillaja saponaria Molina. The compounds were characterized, using NMR spectroscopy, mass spectrometry and monosaccharide analysis, as quillaic acid substituted at C-3 with oligosaccharides consisting of a disaccharide, beta-D-Galp-(1-->2)-beta-D-GlcpA substituted with either D-xylose or L-rhamnose and at C-28 with complex oligosaccharide structures consisting of a disaccharide, alpha-L-Rhap-(1-->2)-4-O-acetyl-beta-D-Fucp, substituted with various amount of D-xylose. D-glucose, D-apiose, and L-rhamnose.


Asunto(s)
Ácido Oleanólico/análogos & derivados , Saponinas/química , Árboles/química , Acetilación , Cromatografía de Afinidad , Espectroscopía de Resonancia Magnética , Metilación , Monosacáridos/análisis , Oligosacáridos/química , Sapogeninas/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
11.
Phytochemistry ; 54(2): 139-45, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10872204

RESUMEN

The kinetic properties and active site amino acids of alpha-1,4-glucan lyase from the marine red macroalga Gracilariopsis sp. were examined. Using 1H NMR spectroscopy the alpha-1,4-glucan lyase was found to degrade alpha- and beta-maltose at different rates. The effect of pH on the kinetic constants suggested the presence of two catalytically important amino acids in the active site with pKa values of 3.5 and 6.2. The former indicated the presence of an ionised aspartate or glutamate residue in the active site. This was tested using the carboxyl specific reagent EDAC, which inhibited enzyme activity in a time dependent manner when an external nucleophile was added. No protection against the inactivation was obtained by addition of amylopectin, maltitol or 1-deoxinojirimycin. Inactivation decreased Vmax over 2.5-fold with little effect on Km which supports the direct involvement of a carboxyl group in catalysis.


Asunto(s)
Polisacárido Liasas/metabolismo , Rhodophyta/enzimología , Sitios de Unión , Carbodiimidas/farmacología , Carbohidratos/farmacología , Inhibidores Enzimáticos/farmacología , Concentración de Iones de Hidrógeno , Cinética , Espectroscopía de Resonancia Magnética , Polisacárido Liasas/antagonistas & inhibidores , Polisacárido Liasas/química
12.
Phytochemistry ; 53(8): 861-8, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10820793

RESUMEN

Seven novel saponins were isolated from a bark extract of Quillaja saponaria Molina. the compounds were characterized, using mainly NMR spectroscopy, mass spectrometry and chemical methods, as quillaic acid substituted at C-3 with oligosaccharides consisting of various compositions of D-glucuronic acid D-galactose, D-xylose, and L-rhamnose and at C-28 with complex oligosaccharide structures consisting of various compositions of D-xylose, L-rhamnose, D-apiose and a branched 4-O-acetyl-D-fucose residue.


Asunto(s)
Ácido Oleanólico/análogos & derivados , Saponinas/aislamiento & purificación , Árboles/química , Triterpenos/química , Acetilación , Secuencia de Carbohidratos , Fucosa/química , Espectroscopía de Resonancia Magnética , Datos de Secuencia Molecular , Saponinas/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
13.
Carbohydr Res ; 323(1-4): 87-97, 2000 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-10782290

RESUMEN

A fraction of saponins from Quillaja saponaria Molina, QH-B, was fractionated by consecutive separations on three different reverse-phase HPLC systems. Eight compounds were isolated and the structures of these were elucidated mainly by sugar analysis and NMR spectroscopy. The structures consisted of a quillaic acid substituted with two different trisaccharides at C-3, beta-D-Galp-(1-->2)-[alpha-L-Rhap-(1-->3)]-beta-D-GlcpA and beta-D-Galp-(1-->2)-[beta-D-Xylp-(1-->3)]-beta-D-GlcpA, and a tetra- or pentasaccharide at C-28, beta-D-Xylp-(1-->4)-[beta-D-Glcp-(1-->3)]-alpha-L-Rhap-(1--> 2)-beta-D-Fucp and beta-D-Apif-(1-->3)-beta-D-Xylp-(1-->4)-[beta-D-Glcp-(1-->3) ]-alpha-L- Rhap-(1-->2)-beta-D-Fucp. These compounds were further substituted with an acyl group either at O-3 or O-4 of the fucose residue, which is the sugar linked to C-28 of the quillaic acid.


Asunto(s)
Ácido Oleanólico/análogos & derivados , Rosales/química , Sapogeninas/química , Saponinas/química , Secuencia de Carbohidratos , Cromatografía de Gases , Cromatografía Líquida de Alta Presión , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Datos de Secuencia Molecular , Saponinas/aislamiento & purificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Factores de Tiempo
14.
Eur J Biochem ; 267(6): 1672-9, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10712598

RESUMEN

The structure of the O-specific side chain of the lipopolysaccharide (LPS) of Plesiomonas shigelloides, strain CNCTC 113/92 has been investigated by NMR spectroscopy, matrix-assisted laser desorption/ionization time of flight mass spectrometry and sugar and methylation analysis. It was concluded that the polysaccharide is composed of a hexasaccharide repeating unit with the following structure: in which D-beta-D-Hepp is Dglycero-beta-Dmanno-heptopyranose and 6d-beta-D-Hep is 6-deoxy-beta-Dmanno-heptopyranose. This structure represents a novel hexasaccharide repeating unit of bacterial O-antigen that is characteristic and unique to the Plesiomonas shigelloides strain. Using the high-resolution magic angle spinning technique, 1H-NMR spectra were also obtained for the O-polysaccharide components of isolated LPS and in their original form directly on the surface of bacterial cells.


Asunto(s)
Antígenos O/química , Oligosacáridos/química , Plesiomonas/química , Secuencia de Carbohidratos , Electroforesis en Gel Bidimensional , Electroforesis en Gel de Poliacrilamida , Espectroscopía de Resonancia Magnética , Datos de Secuencia Molecular , Antígenos O/clasificación , Plesiomonas/clasificación , Serotipificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
15.
Phytochemistry ; 55(5): 419-28, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11140603

RESUMEN

Eight new triterpenoid saponins were isolated from a bark extract of Quillaja saponaria Molina by silica and reverse phase chromatography. The saponins were characterized by spectroscopic data and chemical methods as phytolaccagenic acid, 22beta-hydroxy-quillaic acid, and echinocystic acid substituted with different oligosaccharides at C-3 and C-28. The O-4 of the fucosyl residue in the 28-O-oligosaccharide was substituted with either acetyl, (S)-2-methylbutanoyl, or (3S,4S)-3-hydroxy-4-methylhexanoyl groups.


Asunto(s)
Ácido Oleanólico/análogos & derivados , Rosales/química , Saponinas/química , Triterpenos/química , Conformación de Carbohidratos , Secuencia de Carbohidratos , Espectroscopía de Resonancia Magnética , Datos de Secuencia Molecular , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
16.
Carbohydr Res ; 320(1-2): 70-81, 1999 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-10515062

RESUMEN

Six major saponins were isolated from a bark extract from Quillaja saponaria Molina. Solid-phase extraction, followed by a two-step reversed-phase HPLC separation procedure with phosphate and ammonium acetate buffers of different pH values, was used. The compounds were characterised using NMR spectroscopy, mass spectrometry and chemical methods.


Asunto(s)
Saponinas/química , Saponinas/aislamiento & purificación , Árboles , Conformación de Carbohidratos , Secuencia de Carbohidratos , Cromatografía Líquida de Alta Presión , Indicadores y Reactivos , Modelos Moleculares , Conformación Molecular , Datos de Secuencia Molecular , Oligosacáridos/química , Oligosacáridos/aislamiento & purificación , Tallos de la Planta
17.
Biochemistry ; 38(36): 11788-95, 1999 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-10512635

RESUMEN

The structures of the carbohydrate O-specific side-chain moiety of the lipopolysaccharides (LPS) of Yokenella regensburgei, strains PCM 2476, 2477, 2478, and 2494, have been investigated by (1)H and (13)C NMR, fast atom bombardment tandem mass spectrometry (FAB-MSMS), matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, methylation analysis, partial acid hydrolysis, and immunological methods. It was concluded that the O-specific polysaccharides of strains 2476, 2477, 2478, and 2494 are composed of the same basic trisaccharide repeating unit having the structure -->3)-alpha-D-FucpNAc-(1-->2)-L-alpha-D-Hepp-(1-->3)-6-deoxy -alpha-L- Talp-(1-->, in which L-alpha-D-Hepp is L-glycero-alpha-D-manno-heptopyranose. The detailed analysis revealed, however, differences in O-acetylation patterns of the 6-deoxy-L-talose residue, with 2- and 4-O-acetyl disubstituted -->3)-6-deoxy-alpha-L-Talp-(1--> in strain PCM 2476 and a 2-O-acetylated residue in strains 2477, 2478, and 2494. These structures represent novel, trisaccharide repeating units of bacterial O-antigens that are characteristic and unique to the Y. regensburgeispecies. By use of the high-resolution magic-angle spinning (HR-MAS) technique, (1)H NMR spectra of the O-polysaccharides directly in isolated LPS were obtained. This allowed for almost full assignment and structural determination of the polysaccharide. By this technique the O-polysaccharide components were also observed in their original form directly on the surface of living bacterial cells.


Asunto(s)
Enterobacteriaceae/química , Espectroscopía de Resonancia Magnética/métodos , Antígenos O/química , Conformación de Carbohidratos , Secuencia de Carbohidratos , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Datos de Secuencia Molecular , Especificidad de la Especie , Espectrometría de Masa Bombardeada por Átomos Veloces
18.
Eur J Biochem ; 266(1): 53-61, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10542050

RESUMEN

The structure of the O-specific side-chain of the Hafnia alvei strain PCM 1207 lipopolysaccharide (LPS) has been investigated. Methylation analysis, partial acid hydrolysis, matrix-assisted laser-desorption ionization time-of-flight (MALDI-TOF) MS, fast atom bombardment (FAB)-MS/MS and 1H- and 13C-NMR spectroscopy were the principal methods used. Glycerol phosphate was identified as a constituent in the polysaccharide and the following structure of a pentasaccharide repeating unit was established: The polysaccharide is partially (approximately 10%) substituted with O-acetyl groups. The lipopolysaccharide was also subjected to high resolution magic angle spinning (HR-MAS) NMR analysis, which showed both the signals of the O-specific polysaccharide as well as several signals from unsubstituted core oligosaccharides. This confirmed the presence of the described structure in the native LPS.


Asunto(s)
Enterobacteriaceae/química , Lipopolisacáridos/química , Antígenos O/química , Conformación de Carbohidratos , Secuencia de Carbohidratos , Citrobacter/inmunología , Reacciones Cruzadas , Enterobacteriaceae/inmunología , Epítopos Inmunodominantes/química , Espectroscopía de Resonancia Magnética , Datos de Secuencia Molecular , Espectrometría de Masa Bombardeada por Átomos Veloces , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
19.
Anal Biochem ; 268(1): 35-42, 1999 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-10036159

RESUMEN

A sensitive and selective method for detection and quantification of 1,5-anhydro-D-fructose, microthecin, and 4-deoxy-glycero-hexo-2, 3-diulose using GC-MS in selected ion monitoring mode has been developed. These compounds, which occur in many biological systems, have here been quantified in the red alga Gracilariopsis lemaneiformis. A screening of other algae showed the occurrence of 1, 5-anhydro-D-fructose in several other species of red algae as well as in some green and brown algae.


Asunto(s)
Eucariontes/química , Fructosa/análogos & derivados , Cromatografía de Gases y Espectrometría de Masas/métodos , Cetosas/análisis , Animales , Fructosa/análisis , Control de Calidad , Ratas
20.
Carbohydr Res ; 322(1-2): 46-56, 1999 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-10629948

RESUMEN

The NMR data obtained from hydroxy protons have been used to investigate the presence and absence of intramolecular hydrogen bonding in aqueous solutions of 2-(trimethylsilyl)ethyl galabioside (alpha-D-Galp-(1-->4)-beta-D-Galp-O(CH2)2SiMe3) and the S-linked 4-thiodisaccharide analogue. The data show that there is a weak hydrogen bond interaction between O-6H and O-2'H in galabioside, but not in the thio-analogue. The results are in good agreement with those reported for the substances in a Me2SO-d6 solution. It is also shown that the existence of a hydrogen bond can be quite easily monitored by comparing the NMR data of the hydroxy protons.


Asunto(s)
Disacáridos/química , Tioglicósidos/química , Conformación de Carbohidratos , Enlace de Hidrógeno , Espectroscopía de Resonancia Magnética , Estructura Molecular
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA