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1.
Mar Drugs ; 22(4)2024 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-38667758

RESUMEN

Nemertean worms contain toxins that are used to paralyze their prey and to deter potential predators. Hoplonemerteans often contain pyridyl alkaloids like anabaseine that act through nicotinic acetylcholine receptors and crustacean chemoreceptors. The chemical reactivity of anabaseine, the first nemertean alkaloid to be identified, has been exploited to make drug candidates selective for alpha7 subtype nAChRs. GTS-21, a drug candidate based on the anabaseine scaffold, has pro-cognitive and anti-inflammatory actions in animal models. The circumpolar chevron hoplonemertean Amphiporus angulatus contains a multitude of pyridyl compounds with neurotoxic, anti-feeding, and anti-fouling activities. Here, we report the isolation and structural identification of five new compounds, doubling the number of pyridyl alkaloids known to occur in this species. One compound is an isomer of the tobacco alkaloid anatabine, another is a unique dihydroisoquinoline, and three are analogs of the tetrapyridyl nemertelline. The structural characteristics of these ten compounds suggest several possible pathways for their biosynthesis.


Asunto(s)
Alcaloides , Isoquinolinas , Animales , Alcaloides/farmacología , Alcaloides/química , Alcaloides/aislamiento & purificación , Isoquinolinas/farmacología , Isoquinolinas/química , Isoquinolinas/aislamiento & purificación , Invertebrados/química , Piridinas/farmacología , Piridinas/química , Piridinas/aislamiento & purificación , Receptores Nicotínicos/metabolismo , Receptores Nicotínicos/efectos de los fármacos , Estructura Molecular
2.
Plant J ; 85(6): 743-57, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26920093

RESUMEN

Microalgal triacylglycerol (TAG), a promising source of biofuel, is induced upon nitrogen starvation (-N), but the proteins and genes involved in this process are poorly known. We performed isobaric tagging for relative and absolute quantification (iTRAQ)-based quantitative proteomics to identify Chlorella proteins with modulated expression under short-term -N. Out of 1736 soluble proteins and 2187 membrane-associated proteins identified, 288 and 56, respectively, were differentially expressed under -N. Gene expression analysis on select genes confirmed the same direction of mRNA modulation for most proteins. The MYB-related transcription factor ROC40 was the most induced protein, with a 9.6-fold increase upon -N. In a previously generated Chlamydomonas mutant, gravimetric measurements of crude total lipids revealed that roc40 was impaired in its ability to increase the accumulation of TAG upon -N, and this phenotype was complemented when wild-type Roc40 was expressed. Results from radiotracer experiments were consistent with the roc40 mutant being comparable to the wild type in recycling membrane lipids to TAG but being impaired in additional de novo synthesis of TAG during -N stress. In this study we provide evidence to support the hypothesis that transcription factor ROC40 has a role in -N-induced lipid accumulation, and uncover multiple previously unknown proteins modulated by short-term -N in green algae.


Asunto(s)
Chlorella/fisiología , Ritmo Circadiano/fisiología , Proteínas de Plantas/metabolismo , Factores de Transcripción/metabolismo , Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/metabolismo , Regulación de la Expresión Génica de las Plantas , Prueba de Complementación Genética , Metabolismo de los Lípidos/fisiología , Mutación , Nitrógeno/metabolismo , Proteínas de Plantas/genética , Factores de Transcripción/genética , Triglicéridos/metabolismo
3.
Prenat Diagn ; 34(13): 1326-31, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25102973

RESUMEN

OBJECTIVE: Pulmonary hypoplasia is a major cause of death in lethal skeletal dysplasias. We hypothesize that in fetuses with prenatally diagnosed skeletal dysplasia, comparison of observed-to-expected (O/E) lung volume will help predict lethality. STUDY DESIGN: We conducted a retrospective chart review of patients referred for evaluation of suspected fetal skeletal anomalies. Twenty-three pregnancies were identified with confirmed fetal diagnosis of skeletal dysplasia for which fetal magnetic resonance imaging (MRI) was performed between 21 and 38 weeks of gestation and ultrasound biometry data were available. Femur length to abdominal circumference ratio (FL/AC) and O/E lung volumes were calculated. The association between O/E lung volume, FL/AC, and lethality was measured using logistic regression. RESULTS: Lethality was significantly associated with O/E lung volume (p = 0.002) and FL/AC (p = 0.0476). Analysis with receiver-operating characteristic curves suggested that O/E lung volume of 47.9% or FL/AC of 0.124 could be useful clinical cutoffs in the prediction of lethality. CONCLUSION: In fetuses with skeletal dysplasia, fetal MRI-derived O/E lung volume was predictive of lethality. When evaluating a fetal skeletal dysplasia, fetal MRI may be considered in cases for which ultrasound-based lethality prediction is ambiguous or uncertain in order to provide families with the most complete and accurate information.


Asunto(s)
Enfermedades del Desarrollo Óseo/patología , Enfermedades Fetales/patología , Pulmón/patología , Femenino , Humanos , Masculino , Tamaño de los Órganos , Valor Predictivo de las Pruebas , Embarazo , Resultado del Embarazo , Estudios Retrospectivos
4.
J Pediatr Adolesc Gynecol ; 37(1): 67-71, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37704034

RESUMEN

BACKGROUND: Rubinstein-Taybi syndrome (RSTS) is a multi-system neurodevelopmental condition caused by deficiency of CREBBP (16p13.3) or EP300 (22q13.2). Müllerian agenesis, or Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, is defined as congenital agenesis of the uterus, cervix, and upper vagina without a definite genetic cause. INDEX CASE AND CASE SERIES: We present a 14-year-old female with RSTS type 1 (CREBBP, c.4395-2A>C) and MRKH, the first documented in the literature. Following presentation to Gynecology for anticipatory guidance regarding future menstrual suppression and follow-up of previously diagnosed labial adhesions, exam under anesthesia revealed a single urogenital opening with cystoscopy demonstrating a normal urethra and bladder. Laboratory evaluation was consistent with peripubertal female gonadotropins and estradiol, 46,XX karyotype, and normal microarray, and a pelvic MRI confirmed Müllerian agenesis. Given this case, we assessed our cohort of females with RSTS and found that 4 of 12 individuals also had Müllerian anomalies. CONCLUSION: Gynecologic evaluation should be a part of medical care for females with RSTS, particularly in individuals with delayed menarche or abnormal menstrual history, on the basis of the observed association between RSTS and Müllerian anomalies in this case series. Although several candidate genes and copy number variants are associated with MRKH, no candidate genes in close proximity to the 16p13.3 region have been identified to explain both RSTS and MRKH in the index patient. Due to the regulatory nature of CREBBP during embryonic development, we theorize that CREBBP may play a role in the migration of Müllerian structures during embryogenesis.


Asunto(s)
Trastornos del Desarrollo Sexual 46, XX , Productos Biológicos , Anomalías Congénitas , Síndrome de Rubinstein-Taybi , Femenino , Humanos , Adolescente , Síndrome de Rubinstein-Taybi/genética , Vagina/anomalías , Trastornos del Desarrollo Sexual 46, XX/diagnóstico , Conductos Paramesonéfricos/anomalías , Anomalías Congénitas/genética , Anomalías Congénitas/diagnóstico
5.
Planta ; 238(5): 895-906, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23928654

RESUMEN

Algal lipids are ideal biofuel sources. Our objective was to determine the contributors to triacylglycerol (TAG) accumulation and lipid body formation in Chlorella UTEX29 under nitrogen (N) deprivation. A fivefold increase in intracellular lipids following N starvation for 24 h confirmed the oleaginous characteristics of UTEX29. Ultrastructural studies revealed increased number of lipid bodies and decreased starch granules in N-starved cells compared to N-replete cells. Lipid bodies were observed as early as 3 h after N removal and plastids collapsed after 48 h of stress. Moreover, the identification of intracellular pyrenoids and differences in the expected nutritional requirements for Chlorella protothecoides (as UTEX29 is currently classified) led us to conduct a phylogenetic study using 18S and actin cDNA sequences. This indicated UTEX29 to be more phylogenetically related to Chlorella vulgaris. To investigate the fate of different lipids after N starvation, radiolabeling using ¹4C-acetate was used. A significant decrease in ¹4C-galactolipids and phospholipids matched the increase in ¹4C-TAG starting at 3 h of N starvation, consistent with acyl groups from structural lipids as sources for TAG under N starvation. These results have important implications for the identification of key steps controlling oil accumulation in N-starved biofuel algae and demonstrate membrane recycling during lipid body formation.


Asunto(s)
Biocombustibles , Chlorella/metabolismo , Lípidos de la Membrana/metabolismo , Nitrógeno/deficiencia , Triglicéridos/metabolismo , Acetatos/metabolismo , Radioisótopos de Carbono , Chlorella/clasificación , Chlorella/efectos de los fármacos , Chlorella/ultraestructura , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Ácidos Grasos/metabolismo , Galactolípidos/metabolismo , Nitrógeno/farmacología , Filogenia
6.
Toxins (Basel) ; 15(1)2023 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-36668866

RESUMEN

Nemerteans (also called Nemertines) are a phylum of predominantly marine worms that use toxins to capture prey and to defend themselves against predators. Hoplonemerteans have a proboscis armed with one or more stylets used in prey capture and are taxonomically divided into Order Monostilifera, whose members possess a single large proboscis stylet, and Order Polystilifera, whose members have multiple small stylets. Many monostiliferans contain alkaloidal toxins, including anabaseine, that stimulate and then desensitize nicotinic acetylcholine receptors that are present in all animals. These compounds also interact with pyridyl chemoreceptors in crustaceans, reducing predation and larval settlement. Anabaseine has been a lead compound in the design of alpha7 nicotinic acetylcholine receptor agonists like GTS-21 (also called DMXBA) to treat disorders of cognition such as Alzheimer's disease and schizophrenia. These drug candidates also display anti-inflammatory activities of potential medical importance. Most polystiliferans live deep in open oceans and are relatively inaccessible. We fortunately obtained two live specimens of a large benthic polystiliferan, Paradrepanophorus crassus (Pc), from the coast of Spain. MS and NMR analyses of the Ehrlich's reagent derivative allowed identification of anabaseine. A spectrophotometric assay for anabaseine, also based on its reaction with Ehrlich's reagent, revealed high concentrations of anabaseine in the body and proboscis. Apparently, the biosynthetic mechanism for producing anabaseine was acquired early in the evolution of the Hoplonemertea, before the monostiliferan-polystiliferan divergence.


Asunto(s)
Receptores Nicotínicos , Toxinas Biológicas , Animales , Agonistas Nicotínicos , Anabasina/química
7.
Mol Cytogenet ; 15(1): 10, 2022 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-35248119

RESUMEN

BACKGROUND: Unbalanced translocations may be de novo or inherited from one parent carrying the balanced form and are usually present in all cells. Mosaic unbalanced translocations are extremely rare with a highly variable phenotype depending on the tissue distribution and level of mosaicism. Mosaicism for structural chromosomal abnormalities is clinically challenging for diagnosis and counseling due to the limitation of technical platforms and complex mechanisms, respectively. Here we report a case with a tremendously rare maternally-derived mosaic unbalanced translocation of t(3;12), and we illustrate the unreported complicated mechanism using single nucleotide polymorphism (SNP) array, fluorescence in situ hybridization (FISH), and chromosome analyses. CASE PRESENTATION: An 18-year-old female with a history of microcephaly, pervasive developmental disorder, intellectual disability, sensory integration disorder, gastroparesis, and hypotonia presented to our genetics clinic. She had negative karyotype by parental report but no other genetic testing performed previously. SNP microarray analysis revealed a complex genotype including 8.4 Mb terminal mosaic duplication on chromosome 3 (3p26.3->3p26.1) with the distal 5.7 Mb involving two parental haplotypes and the proximal 2.7 Mb involving three parental haplotypes, and a 6.1 Mb terminal mosaic deletion on chromosome 12 (12p13.33->12p13.31) with no evidence for a second haplotype. Adjacent to the mosaic deletion is an interstitial mosaic copy-neutral region of homozygosity (1.9 Mb, 12p13.31). The mother of this individual was confirmed by chromosome analysis and FISH that she carries a balanced translocation, t(3;12)(p26.1;p13.31). CONCLUSION: Taken together, the proband, when at the stage of a zygote, likely carried the derivative chromosome 12 from this translocation, and a postzygotic mitotic recombination event occurred between the normal paternal chromosome 12 and maternal derivative chromosome 12 to "correct" the partial 3p trisomy and partial deletion of 12p. To the best of our knowledge, it is the first time to report the mechanism utilizing a combined cytogenetic and cytogenomic approach, and we believe it expands our knowledge of mosaic structural chromosomal disorders and provides new insight into clinical management and genetic counseling.

8.
J Antibiot (Tokyo) ; 75(3): 125-135, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35022574

RESUMEN

Trifolitoxin (TFX, C41H63N15O15S) is a selective, ribosomally-synthesized, post-translationally modified, peptide antibiotic, produced by Rhizobium leguminosarum bv. trifolii T24. TFX specifically inhibits α-proteobacteria, including the plant symbiont Rhizobium spp., the plant pathogen Agrobacterium spp. and the animal pathogen Brucella abortus. TFX-producing strains prevent legume root nodulation by TFX-sensitive rhizobia. TFX has been isolated as a pair of geometric isomers, TFX1 and TFX2, which are derived from the biologically inactive primary amino acid sequence: Asp-Ile-Gly-Gly-Ser-Arg-Gln-Gly-Cys-Val-Ala. Gly-Cys is present as a thiazoline ring and the Arg-Gln-Gly sequence is extensively modified to a UV absorbing, blue fluorescent chromophore. The chromophore consists of a conjugated, 5-membered heterocyclic ring and side chain of modified glutamine.


Asunto(s)
Antibacterianos/metabolismo , Péptidos/metabolismo , Procesamiento Proteico-Postraduccional/genética , Secuencia de Aminoácidos , Aminoácidos/genética , Rhizobium/genética
9.
S Afr J Physiother ; 76(1): 1412, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32671277

RESUMEN

BACKGROUND: People with chronic obstructive pulmonary disease (COPD) experience various impairments, reducing quality of life (QoL). Rehabilitation that does not elicit dyspnoea, such as strength training, is recommended to improve patient outcomes. OBJECTIVES: To systematically review evidence for the effectiveness of lower limb strengthening combined with whole-body vibration training (WBVT), versus lower limb strengthening alone, in adults with COPD for improving lower limb muscle strength, functional exercise capacity (FEC), pulmonary function and QoL. METHOD: Eight databases were searched (inception-May 2019). Only randomised controlled trials (RCTs) with PEDro scores ≥ 5/10 were included. Heterogeneity rendered meta-analyses inappropriate; thus data were synthesised narratively. RESULTS: Five RCTs (mean PEDro score: 5.8/10) were included. Only one RCT showed a significant difference for leg press peak force (kg) at 12 weeks (p = 0.001), favouring WBVT. FEC improved significantly (p < 0.05) in favour of WBVT at 3 and 12 weeks. Combined training was not more effective for short-term (≤ 12 weeks) improvements in pulmonary function or QoL. CONCLUSION: Level II evidence suggests that combining strengthening with WBVT has significant beneficial short-term effects on FEC in adults with COPD. Results are limited by the small number of studies and small sample sizes. Combined WBVT and strengthening was not more effective than strengthening alone for improving lower limb muscle strength, pulmonary function and QoL. CLINICAL IMPLICATIONS: Combining low (6-10 Hz) to moderate (24-26 Hz) frequency WBVT with strengthening may be a more effective modality to improve FEC than strengthening alone, should resources allow.

10.
Pediatrics ; 146(5)2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-33060256

RESUMEN

We report a 16-year-old phenotypic female with 46,XY complete gonadal dysgenesis and metastatic dysgerminoma, unexpectedly discovered through direct-to-consumer (DTC) commercial genetic testing. This case underscores the importance of timely interdisciplinary care, including psychosocial intervention and consideration of gonadectomy, to optimize outcomes for individuals with differences of sex development. Her unique presentation highlights the implications of DTC genetic testing in a new diagnostic era and informs general pediatricians as well as specialists of nongenetic services about the value, capabilities, and limitations of DTC testing.


Asunto(s)
Publicidad Directa al Consumidor , Disgerminoma/secundario , Pruebas Genéticas/métodos , Disgenesia Gonadal 46 XY/diagnóstico , Gonadoblastoma/secundario , Neoplasias Ováricas/patología , Adolescente , Biomarcadores de Tumor/sangre , Disgerminoma/sangre , Disgerminoma/diagnóstico por imagen , Disgerminoma/genética , Femenino , Identidad de Género , Genes sry/genética , Disgenesia Gonadal 46 XY/sangre , Gonadoblastoma/sangre , Gonadoblastoma/diagnóstico por imagen , Gonadoblastoma/genética , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/secundario , Neoplasias Ováricas/diagnóstico por imagen , Fenotipo
11.
J Org Chem ; 74(5): 2028-32, 2009 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-19196166

RESUMEN

Microwave-assisted solid-phase syntheses of six "difficult" peptides, H-VVSVV-NH(2) (3), H-VVVSVV-NH(2) (4), H-VIVIG-OH (5), H-TVTVTV-NH(2) (6), H-VKDGYI-NH(2) (7), and H-VKDVYI-NH(2) (8), were achieved utilizing N-(Fmoc-alpha-aminoacyl)benzotriazoles. Extension to the syntheses of Leu-enkephalin (9) and amyloid-beta (34-42) (10) demonstrates that this strategy comprises an efficient route to new and known "difficult" peptides.


Asunto(s)
Péptidos beta-Amiloides/síntesis química , Encefalina Leucina/síntesis química , Fragmentos de Péptidos/síntesis química , Triazoles/química , Péptidos beta-Amiloides/química , Encefalina Leucina/química , Microondas , Estructura Molecular , Oligopéptidos/síntesis química , Oligopéptidos/química , Fragmentos de Péptidos/química
12.
Org Biomol Chem ; 6(24): 4582-6, 2008 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-19039367

RESUMEN

N(alpha)-Fmoc-N(epsilon)-[(7-methoxycoumarin-4-yl)acetyl]-L-lysine (N(alpha)-Fmoc-L-Lys(Mca)-OH) 3 is conveniently prepared by benzotriazole methodology (52% over two steps). N-Acylbenzotriazoles Mca-Bt 2, N(alpha)-Fmoc-L-Lys(Mca)-Bt 4, coumarin-3-ylcarbonyl (Cc)-Bt 5, N(alpha)-Fmoc-L-Lys(Cc)-Bt 7 and N(alpha)-(Cc)-L-Lys(Fmoc)-Bt 9 enable the efficient microwave enhanced solid-phase fluorescent labeling of peptides.


Asunto(s)
Colorantes Fluorescentes/química , Péptidos/química , Ácido Acético/química , Acilación , Ácidos Carboxílicos/química , Cumarinas/química , Lisina/química , Coloración y Etiquetado , Triazoles/química
13.
Anesth Analg ; 104(6): 1356-63, table of contents, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17513626

RESUMEN

BACKGROUND: Caudal blockade is a common technique for pediatric postoperative analgesia. While safe and effective, caudal opioids are associated with troublesome side effects. Caudal clonidine may offer significant analgesic benefits. We prospectively compared the analgesic, side effect, and rehabilitation profiles of caudal clonidine, hydromorphone, or morphine in a group of 60 pediatric patients undergoing ureteral reimplantation. METHODS: Patients aged 6 mo to 6 yr were evenly and randomly enrolled in a double-blind manner. Patients received a single caudal dose of 2 mcg/kg of clonidine, 10 mcg/kg of hydromorphone, or 50 mcg/kg of morphine, combined with 1.0 mL/kg of 0.2% ropivacaine with epinephrine. After sevoflurane in oxygen/air anesthesia, all subjects received proxy nurse-controlled analgesia with morphine. Postoperative pain intensity, use of IV morphine, and side effects were assessed during the first 24 h. Oral intake and discharge home were recorded. RESULTS: Caudal clonidine resulted in less postoperative nausea and vomiting (P = 0.01) and pruritus (P = 0.007) than did caudal hydromorphone or caudal morphine. Caudal morphine produced more sustained initial analgesia than did caudal clonidine (P = 0.02). No difference was observed in pain scores, total morphine use, time to first oral intake or discharge home. No postoperative respiratory depression, excessive sedation, hypotension, or bradycardia was identified. CONCLUSIONS: Although caudal morphine may result in more sustained initial analgesia, caudal clonidine combined with nurse-controlled analgesia appears to provide comparable analgesia with fewer side effects. Based on these results, the use of caudal clonidine may be superior to caudal opioids after pediatric ureteral reimplantation.


Asunto(s)
Amidas/administración & dosificación , Clonidina/administración & dosificación , Hidromorfona/administración & dosificación , Morfina/administración & dosificación , Reimplantación , Uréter/cirugía , Analgesia Epidural , Niño , Preescolar , Método Doble Ciego , Quimioterapia Combinada , Femenino , Humanos , Lactante , Inyecciones Espinales , Masculino , Dolor Postoperatorio/epidemiología , Dolor Postoperatorio/prevención & control , Ropivacaína
16.
J Am Soc Mass Spectrom ; 16(6): 814-24, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15907697

RESUMEN

Propofol (2,6-diisopropyl phenol) is a widely used intravenous anesthetic. To define its pharmacokinetics and pharmacodynamics, methods for its quantitation in biological matrixes have been developed, but its pattern of mass spectral fragmentation is unknown. We found that fragmentation of the [M - H](-) ion (m/z 177) of propofol in both APCI MS/MS and ESI MS/MS involves the stepwise loss of a methyl radical and a hydrogen radical from one isopropyl side chain to give the most intense product ion, [M -H - CH(4)](-), at m/z 161. This two-step process is also the preferred mode of fragmentation for similar branched alkyl substituted phenols. This mode of fragmentation of the [M - H](-) ion is supported by three independent lines of evidence: (1) the presence of the intermediary [M - H - CH(3)](-) radical ion under conditions of reduced collision energy, (2) the determination of the mass of the predominant [M - H - CH(4)](-) product ion by high resolution mass spectrometry, and (3) the pattern of product ions resulting from further fragmentation of the [M - H - CH(4)](-) product ion. Phenols with a single straight chain alkyl substituent, in contrast, undergo beta elimination of the alkyl radical irrespective of the length of the alkyl chain, yielding the most intense product ion at m/z 106. This product ion represents a special case of a stable intermediary radical for the two-step process described for branched side chains, because further elimination of a hydrogen radical from the beta carbon is not possible.


Asunto(s)
Anestésicos Intravenosos/química , Fenoles/química , Propofol/química , Cromatografía Líquida de Alta Presión , Espectrometría de Masas , Estructura Molecular
17.
J Chromatogr A ; 1062(2): 217-25, 2005 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-15679159

RESUMEN

This paper describes the development of a guantitative method for direct and simultaneous determination of three frequently encountered surfactants, amphoteric (cocoamphoacetate, CAA), anionic (sodium laureth sulfate, SLES), and nonionic (alcohol ethoxylate, AE) using a reversed-phase C18 HPLC coupled with an ESI ion-trap mass spectrometer (MS). Chemical composition, ionization characteristics and fragmentation pathways of the surfactants are presented. Positive ESI was effective for all three surfactants in agueous methanol buffered with ammonium acetate. The method enables rapid determinations in small sample volumes containing inorganic salts (up to 3.5 g L(-1)) and multiple classes of surfactants with high specificity by applying surfactant specific tandem mass spectrometric strategies. It has dynamic linear ranges of 2-60, 1.5-40, 0.8-56 mg L(-1) with R2 egual or greater than 0.999, 0.98 and 0.999 (10 microL injection) for CAA, SLES, and AE, respectively.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masa por Ionización de Electrospray/métodos , Tensoactivos/análisis , Aniones , Reactores Biológicos , Sensibilidad y Especificidad
18.
J Agric Food Chem ; 53(15): 6003-10, 2005 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-16028988

RESUMEN

Ellagic acid, ellagic acid glycosides, and ellagitannins found in various fruits and nuts, including muscadine grape, are reported to have potential health-promoting benefits and antioxidant properties. This study isolated and identified several ellagic acid derivatives present in muscadine grapes and determined their relative antioxidant properties (AOX). Compounds were extracted from grape skins and pulp using methanol, and the solvent was evaporated. Isolates were dissolved in citric acid buffer (pH 3.5) and absorbed onto C18 cartridges. Nonretained polyphenolics were collected separately and again partitioned from Sephadex LH-20, whereas retained polyphenolics were first eluted with ethyl acetate followed by methanol. Ellagic acid derivatives were identified on the basis of UV and mass spectra, and the presence of ellagitannins was confirmed by a significant increase in free ellagic acid with HPLC followed by acid hydrolysis. Muscadine grapes contained phenolic acids, flavonols, anthocyanins, ellagic acid, and numerous ellagic acid derivatives. AOX varied in the order ethyl acetate > methanol > C18 nonretained fractions; each correlated to both total phenolics (r = 0.90) and total ellagic acid (r = 0.99) contents. Results of this study revealed previously unidentified ellagic acid derivatives in muscadine grapes.


Asunto(s)
Cromatografía Líquida de Alta Presión , Ácido Elágico/análisis , Flavonoides/análisis , Frutas/química , Fenoles/análisis , Espectrometría de Masa por Ionización de Electrospray , Vitis/química , Antioxidantes/análisis , Glicósidos/análisis , Taninos Hidrolizables/análisis , Polifenoles
19.
Free Radic Biol Med ; 35(12): 1538-50, 2003 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-14680677

RESUMEN

Kinetic and thermodynamic evidence is reported for the role of the peroxymonocarbonate ion, HCO4-, as a reactive oxygen species in biology. Peroxymonocarbonate results from the equilibrium reaction of hydrogen peroxide with bicarbonate via the perhydration of CO2. The kinetic parameters for HCO4- oxidation of free methionine have been obtained (k1 = 0.48 +/- 0.08 M(-1)s(-1) by a spectrophotometric initial rate method). At the physiological concentration of bicarbonate in blood ( approximately 25 mM), it is estimated that peroxymonocarbonate formed in equilibrium with hydrogen peroxide will oxidize methionine approximately 2-fold more rapidly than plasma H2O2 itself. As an example of methionine oxidation in proteins, the bicarbonate-catalyzed hydrogen peroxide oxidation of alpha1-proteinase inhibitor (alpha1-PI) has been investigated via its inhibitory effect on porcine pancreatic elastase activity. The second-order rate constant for HCO4- oxidation of alpha1-PI (0.36 +/- 0.06 M(-1)s(-1)) is comparable to that of free methionine, suggesting that methionine oxidation is occurring. Further evidence for methionine oxidation, specifically involving Met358 and Met351 of the alpha1-PI reactive center loop, has been obtained through amino acid analyses and mass spectroscopic analyses of proteolytic digests of the oxidized alpha1-PI. These results strongly suggest that HCO4- should be considered a reactive oxygen species in aerobic metabolism.


Asunto(s)
Bicarbonatos/química , Dióxido de Carbono/química , Peróxido de Hidrógeno/química , Metionina/química , Especies Reactivas de Oxígeno/química , Secuencia de Aminoácidos , Cromatografía Líquida de Alta Presión , Cinética , Datos de Secuencia Molecular , Oxidación-Reducción , Espectrometría de Masa por Ionización de Electrospray , Espectrofotometría Ultravioleta , alfa 1-Antitripsina/química
20.
J Steroid Biochem Mol Biol ; 82(4-5): 413-24, 2002 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-12589949

RESUMEN

Intestinal or hepatic microsomes from channel catfish converted [4-14C]-testosterone to three major metabolites: 6 beta-hydroxytestosterone, androstenedione and a third metabolite. Formation of the unknown metabolite required NADPH as cofactor. When incubated with 200 microM testosterone, the rate of formation of the unknown metabolite was 265+/-158 pmol/(min mg) protein (mean+/-S.D.) in microsomes from the proximal intestine, 515+/-93 pmol/(min mg) protein in distal intestine and 226+/-42 pmol/(min mg) protein in hepatic microsomes. Comparison of the chromatographic and spectral properties of the unknown metabolite with those of authentic testosterone derivatives showed that this metabolite corresponded to 4-androstene-3 alpha,17 beta-diol. No 3 alpha-reduced metabolite was formed in incubations of testosterone with catfish intestinal cytosol. Testosterone was reduced to 5 alpha-dihydrotestosterone primarily in the cytosolic fraction and not in microsomes. Incubation of progesterone with intestinal microsomes resulted in the formation of a metabolite with properties similar to that of the 3 alpha-reduced testosterone, and this metabolite was identified by co-chromatography with authentic standard as 3 alpha-reduced progesterone. Thus, 3 alpha-hydroxysteroid dehydrogenase is an important pathway in intestinal microsomes of the channel catfish.


Asunto(s)
3-Hidroxiesteroide Deshidrogenasas/metabolismo , Mucosa Intestinal/metabolismo , Microsomas Hepáticos/metabolismo , Progesterona/metabolismo , Testosterona/metabolismo , 3-alfa-Hidroxiesteroide Deshidrogenasa (B-Específica) , Androstenodiona/metabolismo , Animales , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Citosol , Dihidrotestosterona/metabolismo , Hidroxitestosteronas/metabolismo , Ictaluridae , Espectrometría de Masas , NADP/metabolismo
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