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1.
J Psychiatr Res ; 2020 Nov 04.
Artículo en Inglés | MEDLINE | ID: mdl-33190842

RESUMEN

Social impairment is a cardinal feature of schizophrenia spectrum disorders (SZ). Smaller social network size, diminished social skills, and loneliness are highly prevalent. Existing, gold-standard assessments of social impairment in SZ often rely on self-reported information that depends on retrospective recall and detailed accounts of complex social behaviors. This is particularly problematic in people with SZ given characteristic cognitive impairments and reduced insight. Ecological Momentary Assessment (EMA; repeated self-reports completed in the context of daily life) allows for the measurement of social behavior as it occurs in vivo, yet still relies on participant input. Momentary characterization of behavior using smartphone sensors (e.g., GPS, microphone) may also provide ecologically valid indicators of social functioning. In the current study we tested associations between both active (e.g., EMA-reported number of interactions) and passive (GPS-based mobility, conversations captured by microphone) smartphone-based measures of social activity and measures of social functioning and loneliness to examine the promise of such measures for understanding social impairment in SZ. Our results indicate that passive markers of mobility were more consistently associated with EMA measures of social behavior in controls than in people with SZ. Furthermore, dispositional loneliness showed associations with mobility metrics in both groups, while general social functioning was less related to these metrics. Finally, interactions detected in the ambient audio were more tied to social functioning in SZ than in controls. Findings speak to the promise of smartphone-based digital phenotyping as an approach to understanding objective markers of social activity in people with and without schizophrenia.

2.
Clin Proteomics ; 17: 12, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32265614

RESUMEN

Background: Sialolithiasis or salivary gland stones are associated with high clinical morbidity. The advances in the treatment of sialolithiasis has been limited, however, by our understanding of their composition. More specifically, there is little information regarding the formation and composition of the protein matrix, the role of mineralogical deposition, or the contributions of cell epithelium and secretions from the salivary glands. A better understanding of these stone characteristics could pave the way for future non-invasive treatment strategies. Methods: Twenty-nine high-quality ductal stone samples were analyzed. The preparation included successive washings to avoid contamination from saliva and blood. The sialoliths were macerated in liquid nitrogen and the maceration was subjected to a sequential, four-step, protein extraction. The four fractions were pooled together, and a standardized aliquot was subjected to tandem liquid chromatography mass spectrometry (LCMS). The data output was subjected to a basic descriptive statistical analysis for parametric confirmation and a subsequent G.O.-KEGG data base functional analysis and classification for biological interpretation. Results: The LC-MS output detected 6934 proteins, 824 of which were unique for individual stones. An example of our sialolith protein data is available via ProteomeXchange with the identifier PXD012422. More important, the sialoliths averaged 53% homology with bone-forming proteins that served as a standard comparison, which favorably compared with 62% homology identified among all sialolith sample proteins. The non-homologous protein fraction had a highly variable protein identity. The G.O.-KEGG functional analysis indicated that extracellular exosomes are a primary cellular component in sialolithiasis. Light and electron microscopy also confirmed the presence of exosomal-like features and the presence of intracellular microcrystals. Conclusion: Sialolith formation presents similarities with the hyperoxaluria that forms kidney stones, which suggests the possibility of a common origin. Further verification of a common origin could fundamentally change the way in which lithiasis is studied and treated.

3.
Environ Sci Pollut Res Int ; 27(2): 1417-1427, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31749002

RESUMEN

The differences in the mechanism of cadmium (Cd) accumulation in the grains of different wheat (Triticum aestivum L.) cultivars remain unclear. Thus, we conducted a hydroponic experiment in a greenhouse to compare root surface adsorption, root uptake, subcellular distribution, and chemical forms of Cd between low- and high-Cd-accumulating wheat cultivars at seedling stage, to improve our understanding of the differences between cultivars. The results showed that Cd adsorbed on the root surface was mainly in a complexed form, and the total amount of Cd on the Yaomai16 (YM, high-Cd-accumulating genotypes) root surface was higher (p < 0.05) than that on Xinmai9817 (XM, low-Cd-accumulating genotypes). A large amount of Cd ions adsorbed on root surface would cause plant damage and inhibit growth. Comparing the root-to-shoot translocation factors of Cd, the transfer coefficients of YM were 1.017, 1.446, 1.464, and 1.030 times higher than those of XM under 5, 10, 50, and 100 µmol L-1 Cd treatments, respectively. The subcellular distribution of Cd under Cd exposure is mainly in the cell wall and soluble fraction. The proportions of Cd in YM shoot soluble fraction were higher than those in XM, which was the main detoxification mechanism limiting the activity of Cd and may be responsible for low Cd accumulation in grains, while the effects of the chemical forms of Cd on migration and detoxification were not found to be related to Cd accumulation in the kernels.


Asunto(s)
Cadmio/análisis , Raíces de Plantas/metabolismo , Contaminantes del Suelo/análisis , Triticum/metabolismo , Adsorción , Hidroponia , Raíces de Plantas/química , Semillas/metabolismo , Fracciones Subcelulares/química
4.
Oncotarget ; 8(29): 47076-47089, 2017 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-28423364

RESUMEN

Helicobacter pylori infection triggers a cascade of inflammatory stages that may lead to the appearance of non-atrophic gastritis, multifocal atrophic, intestinal metaplasia, dysplasia, and cancer. Deleted in malignant brain tumors 1 (DMBT1) belongs to the group of secreted scavenger receptor cysteine-rich proteins and is considered to be involved in host defense by binding to pathogens. Initial studies showed its deletion and loss of expression in a variety of tumors but the role of this gene in tumor development is not completely understood. Here, we examined the role of DMBT1 in gastric precancerous lesions in Caucasian, African American and Hispanic individuals as well as in the development of gastric pathology in a mouse model of H. pylori infection. We found that in 3 different populations, mucosal DMBT1 expression was significantly increased (2.5 fold) in individuals with dysplasia compared to multifocal atrophic gastritis without intestinal metaplasia; the increase was also observed in individuals with advanced gastritis and positive H. pylori infection. In our animal model, H. pylori infection of Dmbt1-/- mice resulted in significantly higher levels of gastritis, more extensive mucous metaplasia and reduced Il33 expression levels in the gastric mucosa compared to H. pylori-infected wild type mice. Our data in the animal model suggest that in response to H. pylori infection DMBT1 may mediate mucosal protection reducing the risk of developing gastric precancerous lesions. However, the increased expression in human gastric precancerous lesions points to a more complex role of DMBT1 in gastric carcinogenesis.


Asunto(s)
Regulación Neoplásica de la Expresión Génica , Lesiones Precancerosas/genética , Receptores de Superficie Celular/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Animales , Proteínas de Unión al Calcio , Proteínas de Unión al ADN , Modelos Animales de Enfermedad , Grupos Étnicos/genética , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patología , Perfilación de la Expresión Génica , Estudios de Asociación Genética , Infecciones por Helicobacter/complicaciones , Humanos , Ratones , Ratones Noqueados , Estadificación de Neoplasias , Proteínas Supresoras de Tumor
5.
Rev. argent. microbiol ; 49(1): 55-61, mar. 2017. tab
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-843183

RESUMEN

The microbiological quality of honey obtained from different processing points and the environmental quality within honey houses were assessed in the Pampas Region (Argentina). Mold and yeast (MY), culturable heterotrophic mesophilic bacteria (CHMB), the number of spore-forming bacteria as well as the presence of Shigella spp., Salmonella spp. and fecal coliforms were evaluated in 163 samples. These samples were taken from eight honey houses. Results showed that 89 samples had ≤10 CFU of MY/g honey, 69 ranged from 10 to 50 CFU/g and two reached 65.5 CFU/g. Eighty one percent of the samples showed ≤30 CFU of CHMB/g honey and only seven samples had between 50 and 54.25 CFU/g. Thirty six honey samples were obtained from drums: in 25 samples (69.4%) CHMB counts were less than ≤30 CFU/g of honey; in 20 samples (55.5%) the values of MY were between 10 and 50 CFU/g honey and total coliforms were only detected in 20 samples. Fecal coliforms, spores of clostridia as well as Salmonella spp. and Shigella spp were not detected and less than 50 spores of Bacillus spp. per g were observed in the honey from drums. Therefore, the microbiological honey quality within the honey houses did not show any sanitary risks. Our results were reported to honey house owners to help them understand the need to reinforce proper honey handling and sanitation practices.


Este estudio evaluó la calidad microbiológica de la miel dentro de varias plantas de extracción de miel y la calidad del medio ambiente de las mismas en la Región Pampeana (Argentina). Se trabajó con 163 muestras de miel provenientes de 8 plantas de extracción. Se cuantificaron hongos y levaduras, bacterias aeróbicas mesófilas, bacterias esporuladas y esporas de clostridios. Asimismo, se determinó la presencia de Salmonella spp., Shigella spp. y coliformes fecales. Los resultados mostraron que por g de miel, 89 muestras tuvieron menos de 10 UFC de hongos y levaduras, 69 tuvieron entre 10 y 50 UFC y 2 alcanzaron 65,5 UFC. Ochenta y uno por ciento de las muestras presentaron menos de 30 UFC de bacterias aeróbicas mesófilas por g de miel mientras que solo 7 tuvieron entre 50 y 54,25 UFC. Se obtuvieron 36 muestras de miel directamente de tambor: los conteos de bacterias aeróbicas mesófilas fueron ≤ 30 UFC/g de miel en 25 muestras (69,4%); los valores de hongos y levaduras estuvieron entre 10 y 50 UFC en 20 muestras (55,5%) y solo se detectaron coliformes totales. No se observaron coliformes fecales, esporas de clostridios así como tampoco Salmonella spp. y Shigella spp. y se obtuvieron menos de 50 esporas de Bacillus spp./g en miel de los tambores. Se concluye que la calidad microbiológica de la miel en las plantas de extracción no presentó riesgo sanitario. Los resultados fueron entregados a los dueños de las mismas como aporte para que valoren la importancia de reforzar la aplicación de buenas prácticas de manejo y saneamiento.

6.
Rev Argent Microbiol ; 49(1): 55-61, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-27989610

RESUMEN

The microbiological quality of honey obtained from different processing points and the environmental quality within honey houses were assessed in the Pampas Region (Argentina). Mold and yeast (MY), culturable heterotrophic mesophilic bacteria (CHMB), the number of spore-forming bacteria as well as the presence of Shigella spp., Salmonella spp. and fecal coliforms were evaluated in 163 samples. These samples were taken from eight honey houses. Results showed that 89 samples had ≤10CFU of MY/g honey, 69 ranged from 10 to 50CFU/g and two reached 65.5CFU/g. Eighty one percent of the samples showed ≤30CFU of CHMB/g honey and only seven samples had between 50 and 54.25CFU/g. Thirty six honey samples were obtained from drums: in 25 samples (69.4%) CHMB counts were less than ≤30CFU/g of honey; in 20 samples (55.5%) the values of MY were between 10 and 50CFU/g honey and total coliforms were only detected in 20 samples. Fecal coliforms, spores of clostridia as well as Salmonella spp. and Shigella spp were not detected and less than 50 spores of Bacillus spp. per g were observed in the honey from drums. Therefore, the microbiological honey quality within the honey houses did not show any sanitary risks. Our results were reported to honey house owners to help them understand the need to reinforce proper honey handling and sanitation practices.


Asunto(s)
Bacillus , Hongos , Miel , Argentina , Bacillus/aislamiento & purificación , Bacterias , Microbiología de Alimentos , Hongos/aislamiento & purificación , Miel/microbiología
7.
Otolaryngol Clin North Am ; 49(2): 381-93, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26912292

RESUMEN

Nonneoplastic disorders of the salivary glands involve inflammatory processes. These disorders have been managed conservatively with antibiotics, warm compresses, massage, sialogogues, and adequate hydration. Up to 40% of patients may have an inadequate response or persistent symptoms. When conservative techniques fail, the next step is operative intervention. Sialendoscopy offers a minimally invasive option for the diagnosis and management of chronic inflammatory disorders of the salivary glands and offers the option of gland and function preservation. In this article, we review some of the more common nonneoplastic disorders of the parotid gland, indications for diagnostic and interventional sialendoscopy, and operative techniques.


Asunto(s)
Endoscopía/métodos , Glándula Parótida/diagnóstico por imagen , Parotiditis/diagnóstico por imagen , Cálculos de las Glándulas Salivales/diagnóstico por imagen , Enfermedad Aguda , Enfermedad Crónica , Humanos , Cálculos de las Glándulas Salivales/cirugía , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
8.
Rev. Soc. Argent. Diabetes ; 49(2): 50-68, 2015.
Artículo en Español | LILACS | ID: lil-774212

RESUMEN

Introducción: la hipertensión arterial (HA) y la diabetes mellitus (DM) son enfermedades crónicas de alta prevalencia que se encuentran frecuentemente asociadas. Objetivos: brindar los conocimientos para la práctica clínica que favorezcan la toma de decisiones diagnósticas y terapéuticas adecuadas, basadas en las evidencias científicas actuales. Materiales y métodos: utilizando la evidencia disponible, los grandes ensayos clínicos publicados en los últimos cuatro años y la adaptación de los recursos diagnósticos y terapéuticos de nuestro país se elaboraron las presentes “Recomendaciones para la Práctica Clínica”. Conclusiones: la HA aumenta la progresión y el desarrollo de las complicaciones crónicas micro y macrovasculares de la DM. El impacto del tratamiento de la HA es significativo en la reducción de la morbimortalidad de las personas con DM. Por ello, el tratamiento debe ser temprano y las metas de objetivo terapéutico deberán ser individualizadas según grupo etario, comorbilidades y daño de órgano blanco. En todas las personas con HA, tengan o no DM y/o enfermedad renal crónica (ERC), el objetivo es alcanzar una PA <140/90 mmHg. Podrán considerarse objetivos más cercanos a 130/80 mmHg en jóvenes, sin comorbilidades, con larga expectativa de vida y menor tiempo de diagnóstico de DM: en quienes tendrían beneficios a nivel renal o en quienes el riesgo de ACV es sustancial, si se logran sin efectos adversos asociados al tratamiento. Los IECA o ARA II son los fármacos de primera elección excepto en casos de intolerancia o contraindicación. Un bajo porcentaje de personas logra el objetivo terapéutico. La educación es una herramienta fundamental para mejorar la adherencia al tratamiento.


Asunto(s)
Diabetes Mellitus , Hipertensión , Terapéutica
9.
Nucleic Acids Res ; 39(18): 8017-28, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21727086

RESUMEN

Apurinic/apyrimidinic endonuclease-1 (APE1) is a multifunctional DNA repair/gene regulatory protein in mammalian cells, and was recently reported to be phosphorylated at Thr233 by CDK5. We here report that ubiquitination of T233E APE1, a mimicry of phospho-T233 APE1, was markedly increased in multiple cell lines. Expression of CDK5 enhanced monoubiquitination of endogenous APE1. Polyubiquitinated APE1 was decreased when K48R ubiquitin was expressed, suggesting that polyubiquitination was mediated mainly through Lys48 of ubiquitin. The ubiquitination activity of MDM2, consistent in its role for APE1 ubiquitination, was increased for T233E APE1 compared to the wild-type APE1. In mouse embryonic fibroblasts lacking the MDM2 gene, ubiquitination of T233E APE1 was still observed probably because of the decreased degradation activity for monoubiquitinated APE1 and because of backup E3 ligases in the cells. Monoubiquitinated APE1 was present in the nucleus, and analyzing global gene expression profiles with or without induction of a ubiquitin-APE1 fusion gene suggested that monoubiquitination enhanced the gene suppression activity of APE1. These data reveal a delicate balance of ubiquitination and phosphorylation activities that alter the gene regulatory function of APE1.


Asunto(s)
Quinasa 5 Dependiente de la Ciclina/metabolismo , ADN-(Sitio Apurínico o Apirimidínico) Liasa/metabolismo , Ubiquitinación , Sustitución de Aminoácidos , Animales , Línea Celular , Línea Celular Tumoral , ADN-(Sitio Apurínico o Apirimidínico) Liasa/química , ADN-(Sitio Apurínico o Apirimidínico) Liasa/genética , Ácido Glutámico/genética , Humanos , Lisina/metabolismo , Ratones , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Treonina/genética
10.
Theor Appl Genet ; 123(3): 369-82, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21505831

RESUMEN

Quantitative trait loci (QTLs) for frost and drought tolerance, and winter survival in the field, were mapped in meadow fescue (Festuca pratensis Huds.) and compared with corresponding traits in Triticeae and rice to study co-location with putatively orthologous QTLs and known abiotic stress tolerance genes. The genomes of grass species are highly macrosyntenic; however, the Festuca/Lolium and Triticeae homoeologous chromosomes 4 and 5 show major structural differences that is especially interesting in comparative genomics of frost tolerance. The locations of two frost tolerance/winter survival QTLs on Festuca chromosome 5F correspond most likely to the Fr-A1 and Fr-A2 loci on wheat homoeologous group 5A chromosomes. A QTL for long-term drought tolerance on chromosome 3F (syntenic with rice 1) support evidence from introgression of Festuca genome segments onto homoeologous Lolium chromosomes (3L) that this genome region is an excellent source of tolerance towards drought stress. The coincident location of several stress tolerance QTL in Festuca with QTL and genes in Triticeae species, notably dehydrins, CBF transcription factors and vernalisation response genes indicate the action of structural or regulatory genes conserved across evolutionarily distant species.


Asunto(s)
Mapeo Cromosómico , Frío , Sequías , Festuca/genética , Sitios de Carácter Cuantitativo , Cromosomas de las Plantas , Clonación Molecular , Evolución Molecular , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Lolium/genética , Oryza/genética , Estaciones del Año , Factores de Transcripción/genética , Triticum/genética
11.
Cell Mol Life Sci ; 67(21): 3609-20, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20711647

RESUMEN

A key issue in studying mammalian DNA base excision repair is how its component proteins respond to a plethora of cell-signaling mediators invoked by DNA damage and stress-inducing agents such as reactive oxygen species, and how the actions of individual BER proteins are attributed to cell survival or apoptotic/necrotic death. This article reviews the past and recent progress on posttranslational modification (PTM) of mammalian apurinic/apyrimidinic (AP) endonuclease 1 (APE1).


Asunto(s)
ADN-(Sitio Apurínico o Apirimidínico) Liasa/metabolismo , Procesamiento Proteico-Postraduccional , Acetilación , Animales , ADN-(Sitio Apurínico o Apirimidínico) Liasa/química , ADN-(Sitio Apurínico o Apirimidínico) Liasa/genética , Humanos , Modelos Moleculares , Fosforilación , Ubiquitinación
12.
Nucleic Acids Res ; 36(5): 1555-66, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18208837

RESUMEN

The human AP-endonuclease (APE1/Ref-1), an essential multifunctional protein, plays a central role in the repair of oxidative base damage via the DNA base excision repair (BER) pathway. The mammalian AP-endonuclease (APE1) overexpression is often observed in tumor cells, and confers resistance to various anticancer drugs; its downregulation sensitizes tumor cells to those agents via induction of apoptosis. Here we show that wild type (WT) but not mutant p53 negatively regulates APE1 expression. Time-dependent decrease was observed in APE1 mRNA and protein levels in the human colorectal cancer line HCT116 p53(+/+), but not in the isogenic p53 null mutant after treatment with camptothecin, a DNA topoisomerase I inhibitor. Furthermore, ectopic expression of WTp53 in the p53 null cells significantly reduced both endogenous APE1 and APE1 promoter-dependent luciferase expression in a dose-dependent fashion. Chromatin immunoprecipitation assays revealed that endogenous p53 is bound to the APE1 promoter region that includes a Sp1 site. We show here that WTp53 interferes with Sp1 binding to the APE1 promoter, which provides a mechanism for the downregulation of APE1. Taken together, our results demonstrate that WTp53 is a negative regulator of APE1 expression, so that repression of APE1 by p53 could provide an additional pathway for p53-dependent induction of apoptosis in response to DNA damage.


Asunto(s)
Daño del ADN , ADN-(Sitio Apurínico o Apirimidínico) Liasa/genética , Regulación hacia Abajo , Regulación Enzimológica de la Expresión Génica , Proteína p53 Supresora de Tumor/metabolismo , Línea Celular Tumoral , ADN-(Sitio Apurínico o Apirimidínico) Liasa/metabolismo , Humanos , Mutación , Regiones Promotoras Genéticas , ARN Mensajero/metabolismo , Elementos de Respuesta , Factor de Transcripción Sp1/metabolismo , Proteína p53 Supresora de Tumor/genética
13.
Biocell ; 29(3): 279-285, Aug.-Dec. 2005. graf, tab
Artículo en Inglés | LILACS | ID: lil-633234

RESUMEN

Seed size is a crucial plant trait that may potentially affect not only immediate seedling success but also the subsequent generation. We examined variation in seed weight of Wyoming sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young), an excellent candidate species for rangeland restoration. The working hypothesis was that a major fraction of spatial and temporal variability in seed size (weight) of Wyoming sagebrush could be explained by variations in mean monthly temperatures and precipitation. Seed collection was conducted at Battle Mountain and Eden Valley sites in northern Nevada, USA, during November of 2002 and 2003. Frequency distributions of seed weight varied from leptokurtic to platykurtic, and from symmetry to skewness to the right for both sites and years. Mean seed weight varied by a factor of 1.4 between locations and years. Mean seed weight was greater (P<0.05) in 2003 than in 2002 at both sites. This can partially be attributed to 55% greater precipitation in 2003 than 2002, since mean monthly temperatures were similar (P>0.05) in all study situations. Simple linear regression showed that monthly precipitation (March to November) explained 85% of the total variation in mean seed weight ( P=0.079). Since the relationship between mean monthly temperature (June-November) and mean seed weight was not significant (r²=0.00, P=0.431), this emphasizes the importance of precipitation as an important determinant of mean seed weight. Our results suggest that the precipitation regime to which the mother plant is exposed can have a significant effect on sizes of seeds produced. Hence, seasonal changes in water availability would tend to alter size distributions of produced offspring.


Asunto(s)
Artemisia/fisiología , Variación Genética , Semillas/crecimiento & desarrollo , Semillas/fisiología , Clima , Modelos Lineales , Nevada , Lluvia , Estaciones del Año , Especificidad de la Especie , Temperatura
14.
Interciencia ; 30(10): 631-637, oct. 2005. tab, graf
Artículo en Inglés | LILACS | ID: lil-430643

RESUMEN

El tamaño de la semilla y las características de la germinación afectan el desempeño de las plántulas en estadios tempranos. El objetivo de este estudio fue investigar las relaciones entre tamaño de semilla y porcentaje de germinación, tasa de germinación, variación de la germinación con el tiempo y viabilidad de las semillas en artemisa (Artemisia tridentata ssp. wyomingensis Beetle y Young). Las hipótesis de trabajo fueron: 1) para semillas individuales, las tasas y porcentajes de germinación están positivamente relacionados al peso de las semillas; y 2) algunas semillas no teñidas con el TTC no están muertas sino durmientes. Las semillas fueron recolectadas en Battle Mountain y Eden Valley, al norte de Nevada, EEUU, en noviembre 2002 y 2003. Las semillas individuales fueron clasificadas por peso en clases de 0,05mgúsemilla-1, variando de £0,15 a >0,40mgúsemilla-1, y fueron incubadas en oscuridad a 15ºC; las plántulas con radículas ³1,0mm se removieron diariamente durante los primeros 10 días, y luego cada 2 días hasta el día 32. El estudio concluyó el día 37. La prueba del cloruro de trifenil tetrazolio (TTC) se usó para determinar la viabilidad de las semillas no germinadas, y el azul de Evans para separar semillas no germinadas en durmientes o muertas. Los resultados apoyaron ambas hipótesis. La germinación máxima en ambos sitios, años y todos los rangos de semillas se alcanzó 5-6 días luego de la imbibición. Esto sugiere que un suelo húmedo por varios días consecutivos ayudaría a proveer una germinación óptima en campo. El uso del azul de Evans demostró que aunque en pequeño porcentaje (< 5 por ceinto), algunas semillas no teñidas por TTC no estaban muertas sino durmientes, con potencial para germinar dadas condiciones apropiadas. Cuando este arbusto es usado para restaurar pastizales degradados se deberían usar semillas relativamente pesadas, que tienen el mayor potencial para germinar


Asunto(s)
Artemisia , Germinación , Semillas , Agronomía , Estados Unidos
15.
Biocell ; 29(3): 279-85, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16524249

RESUMEN

Seed size is a crucial plant trait that may potentially affect not only immediate seedling success but also the subsequent generation. We examined variation in seed weight of Wyoming sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young), an excellent candidate species for rangeland restoration. The working hypothesis was that a major fraction of spatial and temporal variability in seed size (weight) of Wyoming sagebrush could be explained by variations in mean monthly temperatures and precipitation. Seed collection was conducted at Battle Mountain and Eden Valley sites in northern Nevada, USA, during November of 2002 and 2003. Frequency distributions of seed weight varied from leptokurtic to platykurtic, and from symmetry to skewness to the right for both sites and years. Mean seed weight varied by a factor of 1.4 between locations and years. Mean seed weight was greater (P < 0.05) in 2003 than in 2002 at both sites. This can partially be attributed to 55% greater precipitation in 2003 than 2002, since mean monthly temperatures were similar (P > 0.05) in all study situations. Simple linear regression showed that monthly precipitation (March to November) explained 85% of the total variation in mean seed weight (P = 0.079). Since the relationship between mean monthly temperature (June-November) and mean seed weight was not significant (r2 = 0.00, P = 0.431), this emphasizes the importance of precipitation as an important determinant of mean seed weight. Our results suggest that the precipitation regime to which the mother plant is exposed can have a significant effect on sizes of seeds produced. Hence, seasonal changes in water availability would tend to alter size distributions of produced offspring.


Asunto(s)
Artemisia/fisiología , Variación Genética , Semillas/crecimiento & desarrollo , Semillas/fisiología , Clima , Modelos Lineales , Nevada , Lluvia , Estaciones del Año , Especificidad de la Especie , Temperatura
16.
Biocell ; 29(3): 279-85, 2005 Dec.
Artículo en Inglés | BINACIS | ID: bin-38234

RESUMEN

Seed size is a crucial plant trait that may potentially affect not only immediate seedling success but also the subsequent generation. We examined variation in seed weight of Wyoming sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young), an excellent candidate species for rangeland restoration. The working hypothesis was that a major fraction of spatial and temporal variability in seed size (weight) of Wyoming sagebrush could be explained by variations in mean monthly temperatures and precipitation. Seed collection was conducted at Battle Mountain and Eden Valley sites in northern Nevada, USA, during November of 2002 and 2003. Frequency distributions of seed weight varied from leptokurtic to platykurtic, and from symmetry to skewness to the right for both sites and years. Mean seed weight varied by a factor of 1.4 between locations and years. Mean seed weight was greater (P < 0.05) in 2003 than in 2002 at both sites. This can partially be attributed to 55


greater precipitation in 2003 than 2002, since mean monthly temperatures were similar (P > 0.05) in all study situations. Simple linear regression showed that monthly precipitation (March to November) explained 85


of the total variation in mean seed weight (P = 0.079). Since the relationship between mean monthly temperature (June-November) and mean seed weight was not significant (r2 = 0.00, P = 0.431), this emphasizes the importance of precipitation as an important determinant of mean seed weight. Our results suggest that the precipitation regime to which the mother plant is exposed can have a significant effect on sizes of seeds produced. Hence, seasonal changes in water availability would tend to alter size distributions of produced offspring.

17.
Interciencia ; 29(6): 303-310, jun. 2004. tab
Artículo en Inglés | LILACS | ID: lil-399876

RESUMEN

Se estudiaron las relaciones entre los mecanismos de adquisición de recursos del suelo y los componentes de producción de tejido foliar en la especie de etapas serales tardías, tolerante al pastoreo y competitiva Stipa clarazii Ball y en las especies de etapas serales mas tempranas, menos tolerantes al pastoreo y competitivas S tenius Phil y S. ambigua Speg. La hostoria del pastoreo y/o fuego determina la abundancia de estas gramíneas perennes cespitosas C3 en los pastizales templados semiáridos de Argentina. La hipótesis de trabajo fue que las plantas defoliadas tendrían menor densidad de longitud de raíces (DLR) y porcentaje y porcentaje de colonozación por micorrizas vesiculares-arbusculares (por ciento MAV) que aquellas no defoliadas y no defoliadas de S. clarazii tendrían mayores valores de DRL y por cientoMAV que aquellas de las otras especies, por su mayor capacidad competitiva con tolerancias a la defoliación. Se condujo un estudio bajo condiciones de campo en un área excluída añ pastoero por herbívoros domésticos durante 2 años. Un grupo de plantas fue defoliado una vez a 5cm del suelo a principios de primavera, mientras que otro grupo fue defoliado dos veces, a principios y mediados de primavera. Un tercer grupo permaneció no defoliado. Las mediciones se condujeron 6-10 días después de cada defoliación, y al final de la estación de crecimiento. DLR y por cientoMAV fueron similares en plantas defoliadas en las tres especies. La mayor producción de rebrote en S. clarazii no estuvo asociado con mayores DLR y por cientoMAV en la especie más competitiva. La relación positiva entre DLR y producción de peso seco, o la concentración de N y P en el tejido de estas especies, sugiere que su actividad radical debe mantenerse tras la defoliación para establecer una superficie fotosintética y mantener la distribución de recursos en equilibrio. Todas las especies mostraron valores consistentemente altos de por cientoMAV, sugeriendo que pueden tener una asociación mutualística obligada con las micorrizas. La correlación negativa entre por cientoMAV y DRL o P disponible del suelo para S. clarazii podría representar un mecanismo para evitar cambios de asociación mutualística a parasística en la relación planta-micorriza


Asunto(s)
Concentración al Nivel del Suelo , Suelo , Agronomía , Argentina
18.
Genetics ; 162(3): 1389-400, 2002 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-12454082

RESUMEN

Orthologous regions in barley, rice, sorghum, and wheat were studied by bacterial artificial chromosome sequence analysis. General microcolinearity was observed for the four shared genes in this region. However, three genic rearrangements were observed. First, the rice region contains a cluster of 48 predicted small nucleolar RNA genes, but the comparable region from sorghum contains no homologous loci. Second, gene 2 was inverted in the barley lineage by an apparent unequal recombination after the ancestors of barley and wheat diverged, 11-15 million years ago (mya). Third, gene 4 underwent direct tandem duplication in a common ancestor of barley and wheat 29-41 mya. All four of the shared genes show the same synonymous substitution rate, but nonsynonymous substitution rates show significant variations between genes 4a and 4b, suggesting that gene 4b was largely released from the strong purifying selection that acts on gene 4a in both barley and wheat. Intergenic retrotransposon blocks, many of them organized as nested insertions, mostly account for the lower gene density of the barley and wheat regions. All but two of the retrotransposons were found in the regions between genes, while all but 2 of the 51 inverted repeat transposable elements were found as insertions in genic regions and outside the retrotransposon blocks.


Asunto(s)
Evolución Biológica , Grano Comestible/genética , Genoma de Planta , Cromosomas Artificiales Bacterianos , Elementos Transponibles de ADN , Datos de Secuencia Molecular , Mutación Puntual , Análisis de Secuencia de ADN
19.
Funct Integr Genomics ; 2(1-2): 70-80, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-12021852

RESUMEN

Sequencing of a contiguous 215-kb interval of Triticum monococcum showed the presence of five genes in the same order as in previously sequenced colinear barley and rice BACs. Gene 2 was in the same orientation in wheat and rice but inverted in barley. Gene density in this region was 1 gene per 43 kb and the ratio of physical to genetic distance was estimated to be 2,700 kb cM(-1). Twenty more-or-less intact retrotransposons were found in the intergenic regions, covering at least 70% of the sequenced region. The insertion times of 11 retrotransposons were less than 5 million years ago and were consistent with their nested structure. Five new families of retro-elements and the first full-length elements for two additional retrotransposon families were discovered in this region. Significantly higher values of GC content were observed for Triticeae BACs compared with rice BACs. Relative enrichment or depletion of certain dinucleotides was observed in the comparison of introns, exons and retrotransposons. A higher proportion of transitions in CG and CNG sites that are targets for cytosine methylation was observed in retrotransposons (76%) than in introns (37%). These results showed that the wheat genome is a complex mixture of different sequence elements, but with general patterns of content and interspersion that are similar to those seen in maize and barley.


Asunto(s)
Mapeo Cromosómico , Elementos Transponibles de ADN , Recombinación Genética , Triticum/genética , Cromosomas Artificiales Bacterianos , Evolución Molecular , Secuencia Rica en GC , Familia de Multigenes , Filogenia , Retroelementos , Análisis de Secuencia de ADN , Secuencias Repetidas Terminales
20.
Biocell ; 26(3): 309-17, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12619563

RESUMEN

The effects of water stress on leaf water relations and growth are reported for three perennial tussock grass genotypes under glasshouse conditions. Studies were performed in genotypes El Palmar INTA and Selección Anguil of Agropyron scabrifolium (Döell) Parodi, and El Vizcachero of A. elongatum (Host) Beauv. Agropyron scabrifolium El Palmar INTA is native to a region with warm-temperate and humid climate without a dry season, and an average annual precipitation of 900 mm. Agropyron scabrifolium Selección Anguil comes from a region with a sub-humid, dry to semiarid climate and a mean annual precipitation of 600 mm. Agropyron elongatum is a widespread forage in semiarid Argentina with well-known water stress resistance. A mild water stress treatment was imposed slowly; plants reached a minimum pre-dawn leaf water potential of about -1.83 MPa by day 21 after watering was withheld. In all genotypes, water stress led to a reduction of leaf growth. There was a tendency for a greater epicuticular wax accumulation on water-stressed plants of A. scabrifolium Selección Anguil and A. elongatum than on those of A. scabrifolium El Palmar INTA. This may have contributed to obtain greater turgor pressures and relative water contents in the first two than in the later genotype. In turn, this may have contributed to determine smaller leaf growth rate reductions in A. scabrifolium Selección Anguil and A. elongatum than in A. scabrifolium El Palmar INTA under water stress. This study demonstrated variation in water stress resistance between genotypes in A. scabrifolium, and between A. scabrifolium Selección Anguil and A. elongatum versus A. scabrifolium El Palmar INTA, which was related to their differential responses in water relations.


Asunto(s)
Agropyron/genética , Agropyron/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Agua/metabolismo , Agricultura , Agropyron/efectos de los fármacos , Desastres , Presión Osmótica , Hojas de la Planta/efectos de los fármacos , Factores de Tiempo , Agua/farmacología , Ceras/análisis
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