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Search Results: 1 - 10 of 39994 matches for " Emma; Rojas-Martínez "
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Presencia de fitoplasmas en papayo (Carica papaya) en México
Rojas-Martínez, Reyna I.;Zavaleta-Mejía, Emma;Rivas-Valencia, Patricia;
Revista Chapingo. Serie horticultura , 2011,
Abstract: tissue samples of papayo plants with mosaic and yellow crinkle symptoms collected from michoacan and veracruz were examined to detect phytoplasma with polymerase chain reaction (pcr), using primers derived from ribosomal rna 16s and 23s from phytoplasmas. the sequences of the amplified pcr products were homologous to polynucleotide sequences belonging to phytoplasmas. the restriction patterns obtained through digestion of the amplified dna evidenced the presence of two phytoplasmas in plants showing mosaic and yellow crinkle symptoms. one of them matched the aster yellow group 1 16s subgroup c. the patterns of the other phytoplasmas did not match any of the restriction patterns up to now reported. tissue from diseased plants reacted positively to the fluororochrome-4,6-dyamidino-2- phenylindol (dapi) which stains dna, therefore suggesting the presence of nucleic acids from biotic agents inside the phloem.
Virus associated with thickening of the cladodes of prickly pear (Opuntia ficus-indica Mill.)
Alba Suaste-Dzul,Reyna Isabel Rojas-Martínez,Daniel Ochoa-Martínez,Emma Zavaleta-Mejía
Journal of Biotechnology and Biodiversity , 2012,
Abstract: Symptoms putative to phytoplasmas and virus as yellowing, mosaic, proliferation and deformation of fruits andthickening of the cladodes of prickly pear have been observed in Nopaltepec, Estado de México. The objective ofthis investigation was to detect the presence of virus in samples of prickly pear showing thickening syndrome of thecladodes. The analysis of double-stranded RNA in prickly pear tissue whit the symptoms mentioned above revealedthe presence of viral RNA. In symptomatic tissue, flexible rods of 950-1700 nm in length were observed with the aidof transmission electron microscopy. The virus was transmitted mechanically to Nicotiana tabacum var. Xanthi, N.glutinosa, N. occidentalis, N. benthamiana, Chenopodium quinoa, C. amaranticolor and Datura stramonium.Results from RT-PCR indicate that the particle does not correspond to TMV, neither to member of the Potyviridaefamily or species of the genus Potexvirus.
Virulence and Genetic Variation of Isolates of Colletotrichum gloeosporioides (Penz.) Penz. and Sacc. on Mango (Mangifera indica L.) cv. Haden
Rojas-Martínez, Reyna Isabel;Zavaleta-Mejía, Emma;Nieto-ángel, Daniel;Acosta-Ramos, Marcelo;
Revista mexicana de fitopatología , 2008,
Abstract: the virulence and genetic variation shown by rapd (random amplified polymorphic dna) were determined for 15 monoconidial isolates of colletotrichum gloeosporioides obtained from leaves and fruits of mango (mangifera indica) cv. haden. they were classified into four groups according to their degree of virulence onto inoculated leaves: very virulent (from 19.2 to 9.0% severity, isolates f3, f4, and t5), virulent (from 8.0 to 5.0%, t4, t3, f5, and t1), moderately virulent (from 3.8 to 1.2%, h4, h2, t6, f2, and h3), and scarcely virulent (from 0.1 to 0.01%, h1, f1, and t2). f3 was the most virulent as it showed the highest anthracnose severity. isolates h4, h1, h2, h3, t6, f2, and t2, showed greater genetic variability and were part of a group that was well separated from f3, f4, and f5. these three were outside the main groups in the dendrogram that was constructed from results of the rapd analysis. t5 (very virulent) was associated with t3 and t4 (virulent); however, f1 (scarcely virulent) was grouped with f5 (virulent). the results from the rapd analysis suggest the existence of great genetic variability among the 15 isolates of c. gloeosporioides.
Identificación de un aislamiento del grupo 16SrIII, Candidatus Phytoplasma pruni en plantas y semillas de amaranto (Amaranthus hypochondriacus L.) en México
Rojas-Martínez, Reyna I.;Zavaleta-Mejía, Emma;Lee, Ing-Ming;Aragón-García, Agustín;
Agrociencia , 2009,
Abstract: recently in the state of tlaxcala, méxico, the "witches' broom syndrome" (proliferation of shoots and reduction of internodes) was observed in amaranth (amaranthus hypochondriacus l.). this symptomatology in the field is uniformly distributed in the plantation rather than randomly or in patches, and the most severe damage is in the panicle which contains the seeds, generating considerable losses in the harvest. therefore, the objective of the present study was to determine the presence of phytoplasmas in plants with symptoms of witches' broom syndrome and in seeds from diseased plants. in all of the samples that were processed an associated phytoplasma was found pertaining to the group 16sr iii, according to the results of the comparison of the patterns generated with enzymes of restriction of the products amplified by pcr. the sequences of the products obtained presented similarity of 98 % with the phylogenic group 16sr iii candidatus phytoplasma pruni.
Etiología y efecto en genotipos del pardeamiento y la brotación anormal asociado con fitoplasmas en tubérculos de papa Etiology and effect in genotypes of browning and abnormal sprout associated to phytoplasmas in potato tubers
Margarita Díaz-Valasis,Mateo Armando Cadena-Hinojosa,Reyna Isabel Rojas-Martínez,Emma Zavaleta-Mejía
Revista mexicana de ciencias agrícolas , 2010,
Abstract: La punta morada de la papa afecta el rendimiento y la calidad de los tubérculos por el pardeamiento y la brotación anormal asociados con ésta. Esta enfermedad es considerada de origen fitoplásmico, aunque los postulados de Koch no han sido debidamente probados. Esta investigación intenta determinar la etiología del pardeamiento y la brotación anormal en papa; para ello, se transmitieron mediante injerto, aislamientos procedentes de 19 genotipos de papa de campo con cuatro variedades: Sangema que tuvo 52.63% de transmisión, Michoacán que tuvo 42.1%, Norte a con 31.57% y NAU-6 que alcanzó 65.2%. Los esquejes de papas de invernadero con síntomas de punta morada transmitidos por semilla-tubérculo, indujeron síntomas de "popotillo" en jitomate; sin embargo, al volver a injertar en papa no se observaron síntomas en el follaje, tampoco pardeamiento en los tubérculos y no se detectó fitoplasma mediante la técnica de reacción en cadena de la polimerasa. El porcentaje de transmisión para la punta morada de la papa en invernadero fue de 37%. El pardeamiento y la brotación anormal en los tubérculos fueron inducidos por un patógeno infeccioso, trasmitido hasta por seis injertos sucesivos en invernadero. El porcentaje de detección de fitoplasma con polimerasa en follaje y tubérculo de las variedades utilizadas NAU-6, Norte a, Michoacán y Alpha fue de 37.5, 10, 35.7 y 28.6 respectivamente. En chile manzano y mixquic, éste fue de 70.83% y 66.6%, en tomate no se registraron fitoplasmas. Las plantas de chile, puede actuar como hospedante intermediario en la transmisión del patógeno involucrado con esta enfermedad. Potato purple top affects yield and tubers quality by browning and the abnormal sprout associated with it. This disease is considered of phytoplasmic origin, although Koch postulates have not been properly proven. This investigation tries to determine etiology for browning and abnormal sprouting in potato; taking this into account isolations coming from 19 genotypes of field potato with four varieties were transmitted by means of graft: Sangema that had 52.63% transmission, Michoacán that had 42.1%, Norte a with 31.57% and NAU-6 that reached 65.2%. The greenhouse potatoes cuttings with symptoms of purple tip transmitted by seed-tuber, induced symptoms of "popotillo" in red tomato; however, when grafting again in potato symptoms were not observed in the foliage, neither browning in the tubers and phytoplasma was not detected by means of reaction technique in polymerase chain. The transmission percentage for potato purple tip in greenhouse was of 37%. The brownin
Detección de geminivirus asociados a la alstroemeria (alstroemeria l.) En villa guerrero, estado de México
Cervantes-Díaz,Lourdes; Zavaleta-Mejía,Emma; Rojas-Martínez,Reina Isabel; Alanís-Martínez,Iobana; Ochoa-Martínez,Daniel Leobardo; Valadez-Moctezuma,Ernestina; Grimaldo-Juárez,Onécimo;
Interciencia , 2009,
Abstract: in alstroemeria (alstroemeria l.) plantations located in villa guerrero, mexico state, plants with symptoms similar to those induced by geminivirus in other horticultural crops have been detected. in addition, the presence of whiteflies, which are considered the most efficient vectors of these viruses, has been observed in these plantations. the goal of this work was to detect the presence of this geminivirus species in alstroemeria plants. by means of pcr analysis using primers motcp2118/motcp2123, a fragment of ~600pb similar to the amplicon obtained from phyvv-infected positive control was amplified only from symptomatic plants. nicotiana glutinosa, n. benthamiana, n. rustica, n. tabacum var. xanthi and datura stramonium plants were inoculated by bombardment with total dna obtained from symptomatic alstroemerias and positive to phyvv by means of pcr. inoculated plants showed mild mosaics and deformation of leaves, whereas in the leaves of capsicum annum plants, mosaics, vein necrosis and blisters were observed. using dna from these plants as template in pcr, amplicons corresponded to phyvv were also obtained; however, in bombarded monocotyledons, including alstroemeria, this fragment was not detected. the sequence of oligonucleotides from the pcr products showed 98% homology to phyvv geminivirus. even though symptoms presented by alstroemeria plants in the field were not reproduced, the presence of a geminivirus similar to phyvv in tissue of symptomatic plants was evidenced through pcr.
Etiología y efecto en genotipos del pardeamiento y la brotación anormal asociado con fitoplasmas en tubérculos de papa
Díaz-Valasis, Margarita;Cadena-Hinojosa, Mateo Armando;Rojas-Martínez, Reyna Isabel;Zavaleta-Mejía, Emma;Ochoa-Martínez, Daniel;Bujanos-Mu?iz, Rafael;
Revista mexicana de ciencias agrícolas , 2010,
Abstract: potato purple top affects yield and tubers quality by browning and the abnormal sprout associated with it. this disease is considered of phytoplasmic origin, although koch postulates have not been properly proven. this investigation tries to determine etiology for browning and abnormal sprouting in potato; taking this into account isolations coming from 19 genotypes of field potato with four varieties were transmitted by means of graft: sangema that had 52.63% transmission, michoacán that had 42.1%, norte?a with 31.57% and nau-6 that reached 65.2%. the greenhouse potatoes cuttings with symptoms of purple tip transmitted by seed-tuber, induced symptoms of "popotillo" in red tomato; however, when grafting again in potato symptoms were not observed in the foliage, neither browning in the tubers and phytoplasma was not detected by means of reaction technique in polymerase chain. the transmission percentage for potato purple tip in greenhouse was of 37%. the browning and the abnormal sprouting in tubers were induced by an infectious pathogen, transmitted until for six successive grafts in greenhouse. the percentage of phytoplasma detection with polymerase in foliage and tuber of used varieties nau-6, norte?a, michoacán and alpha were of 37.5, 10, 35.7 and 28.6 respectively. in chili manzano and mixquic, this was of 70.83% and 66.6%, in tomato there were not recorded phytoplasmas. in chili plants, it can act as intermediary host in transmission of pathogen involved with this disease.
Optimal cutoff points for the detection of undiagnosed type 2 diabetes, hypertension and metabolic syndrome in Mexican adults
Rojas-Martínez,Rosalba; Aguilar-Salinas,Carlos A; Jiménez-Corona,Aída;
Salud Pública de México , 2012, DOI: 10.1590/S0036-36342012000100003
Abstract: objective: to compare the waist circumference cutoff points established by the american heart association and the national heart, lung and blood institute (aha/nhlbi) with those of the international diabetes federation (idf) for the screening of diabetes, hypertension, and metabolic syndrome in mexican adults. material and methods: this study comprised a subsample of the ensanut 2006. subjects without diabetes and hypertension and non-pregnant women were included. sensitivity, specificity, and predictive values were compared using auc and the positive likelihood ratio test [lr(+)]. results: in subjects aged ≥40 years, sensitivity for detection of diabetes and hypertension was higher for the idf thresholds (85.34 and 86.87%, respectively) compared with those of the aha/nhlbi (59.49 and 52.41%, respectively). lr(+) were higher for idf thresholds compared with aha/nhlbi. similar results in subjects aged ≥65 years were observed. conclusions: the measurement of abdominal obesity defined by the idf was a better screening tool for diabetes and hypertension, considering that initially a high sensitivity and low cost tool at population level is required.
Lista actualizada y estado de conservación de los mamíferos del Parque Nacional El Chico, Hidalgo, México
HERNáNDEZ-FLORES, S.D.;ROJAS-MARTíNEZ, A.E.;
Acta zoológica mexicana , 2010,
Abstract: we present a check-list of mammals of el chico national park based in field surveys realized between years 2004 to 2008. the mammals identificated were 30 species and 11 are recorded for the first time in the park: glaucomys volans, peromyscus melanotis, reithrodontomys megalotis, r. sumichrasti, spilogale gracilis, cryptotis mexicana, sorex saussurei, dermanura azteca, corynorhinus towsendii, eptesicus fuscus, lasiurus cinereus, myotis californicus y m. velifer. the most abundant species belonged to rodentia and carnivora. threatened species account for 16.67 % of the richness (c. mexicana, s. saussurei, sciurus oculatus, g. volans y corynorhinus mexicanus). mammals in this park are threatened by human settlements and excessive tourism. el chico national park is important for conservation and management of mammals as 23.8% of the mammalian diversity of the state of hidalgo.
Cuidando al cuidador: efectos de un programa educativo
Díaz-álvarez,Juan Carlos; Rojas-Martínez,María Victoria;
Aquichán , 2009,
Abstract: this study examines the results of a 12-month research project entitled effects of the ‘caring for caregivers’ ¨program on a group of family caregivers in the cities of girardot and flandes in association with the university of cundinamarca. objective: assess the effectiveness of the aforementioned program, which was conducted by the national university of colombia for family caregivers of chronically ill persons in the aforementioned cities in the departments of cundinamarca and tolima (colombia). method: the care ability inventory (cai) proposed by ngozi o. nkongho was applied as a pre and post-test. the study is quasi-experimental and involved 72 family caregivers distributed into two groups: a control group made up of 35 persons and an experimental group of 37 caregivers. results: the findings demonstrate the effectiveness of the program in helping the experimental group to develop know-how and patience. the value aspect remained unchanged in both the control group and the experimental group, which indicates the program was not effective in terms of increasing value as a dimension of care.
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