4,451 research outputs found
In vitro regeneration and genetic fidelity of Tigridia pavonia (L.f.) DC.
Plants of Tigridia pavonia (L.f.) DC were regenerated from twin-scaling explants cultured on Murashige and Skoog and N6 basal medium. The highest formation of shoots per responding explant was obtained on N6 medium supplemented with 4.5 µM 2,4-dichlorophenoxy acetic acid in combination with 2.2 µM benzylaminopurine. Shoots rooted readily on N6 basal medium supplemented with 1 g l-1 activated charcoal and 2.6 µM naphtalenacetic acid. The rooted shoots achieved 100% survival. Inter Simple Sequence Repeat analysis was carried out to check for possible genetic alterations in plants obtained after two consecutive subcultures. The results revealed that the recovered plants did not exhibit any type of polymorphism
Variety discrimination of Tigridia pavonia (L.f.) DC. assesed by different length RAPD primers
Tigridia pavonia (L.f.) DC. is one of the important phytogenetic resources of México. This species is used as ornamental, food and medicinal purposes. Despite its ornamental and economic potential, there is little information about the genetic variability. In this study, randomly amplified polymorphic DNA (RAPD) primers of 10, 15 and 20 bases were used to assess the level of genetic variation among nine botanical varieties of Tigridia pavoniacollected in three localities within State of México. The total number fragments, polymorphic fragments, percentage of polymorphism and resolving power were greater for 15 base (55, 52, 94.5 and 5, respectively) and 20 base (47, 45, 95.7 and 3.8, respectively), in comparison with those obtained from 10 base primers (44, 41, 93.1 and 3.6, respectively).Resultsshowed the major effectiveness of 15 and 20 bases RAPD primers in the genetic differentiation of varieties as compared to 10 bases RAPD primers. The dendrograms based on un-weighted pair group method arithmetic average (UPGMA) analysis of the 10, 15, 20 and the pooled (10, 15 and 20) bases RAPD data were consistent in the clustering varieties, grouping them in two main clusters
New Modulation Technique to Mitigate Common Mode Voltage Effects in Star-Connected Five-Phase AC Drives
Star-connected multiphase AC drives are being considered for electromovility applications such as electromechanical actuators (EMA), where high power density and fault tolerance is demanded. As for three-phase systems, common-mode voltage (CMV) is an issue for multiphase drives. CMV leads to shaft voltages between rotor and stator windings, generating bearing currents which accelerate bearing degradation and produce high electromagnetic interferences (EMI). CMV effects can be mitigated by using appropriate modulation techniques. Thus, this work proposes a new Hybrid PWM algorithm that effectively reduces CMV in five-phase AC electric drives, improving their reliability. All the mathematical background required to understand the proposal, i.e., vector transformations, vector sequences and calculation of analytical expressions for duty cycle determination are detailed. Additionally, practical details that simplify the implementation of the proposal in an FPGA are also included. This technique, HAZSL5M5-PWM, extends the linear range of the AZSL5M5-PWM modulation, providing a full linear range. Simulation results obtained in an accurate multiphase EMA model are provided, showing the validity of the proposed modulation approach.This work has been supported in part by the Government of the Basque Country within the fund for research groups of the Basque University system IT978-16 and in part by the Government of the Basque Country within the research program ELKARTEK as the project ENSOL (KK-2018/00040)
Técnicas tradicionales y biotecnológicas en el mejoramiento genético del rosal
La Facultad de Ciencias AgrÃcolas de la Universidad Autónoma del Estado de México, a través de su Centro de Investigación y Estudios Avanzados en Fitomejoramiento, publica en español esta recopilación de trabajos de investigación sobre los avances actuales en el mejoramiento genético de la especie Rosa spp., mediante el empleo de técnicas convencionales (hibridización, propagación asexual) y biotecnológicas (micropropagación, mutagénesis, marcadores moleculares), dirigida a estudiantes, técnicos, profesionistas, asociaciones de productores, viveristas e investigadores interesados en el tema, con la confianza de que este primer esfuerzo permita iniciar y fomentar trabajos formales interinstitucionales en estudios de Fitomejoramiento aplicados a ésta y otras especies con potencial ornamental, para incrementar el aprovechamiento de los recursos fitogenéticos nacionales. Cabe mencionar que en nuestro paÃs se ha trabajado muy poco en el mejoramiento genético de rosa, no obstante la enorme importancia de este cultivo en el mercado comercial de la Floricultura. En la primera parte de la obra, el lector reconocerá la importancia económica del cultivo de la rosa en el contexto nacional e internacional por sus volúmenes de producción y exportación, asà como de sus usos y aplicaciones en el sector industrial, definiendo con precisión las caracterÃsticas de calidad de los cultivares desarrollados, o por desarrollar, para satisfacer los gustos y preferencias del consumidor. Además, se incluye la clasificación actual del género Rosa (en subgéneros y secciones), su descripción botánica, distribución y clasificación en rosales silvestres (antiguos y modernos) propuesta por la Sociedad Americana de la Rosa con base en la historia de la domesticación de esta especie. En el siguiente capÃtulo se describen los mecanismos de polinización y las pruebas de viabilidad y calidad del polen, asà como la botánica y otras caracterÃsticas fisiológicas del fruto (aquenio), maduración de las semillas y tratamientos para su germinación. Se aborda también la genética poliploide y el origen citogenético de sus especies, y la enorme dificultad que ello implica para su identificación, asà como aspectos relacionados con la hibridación intergenérica e interespecÃfica que han llevado a cabo los fitomejoradores y productores para obtener materiales comerciales con caracteres deseables por transferencia de genes y sus implicaciones a nivel de meiosis. De manera adicional, en el tema de propagación asexual, se describen las ventajas y desventajas del uso de portainjertos de rosal y sus caracterÃsticas de utilización dentro y fuera del invernadero. Se revisa el fenómeno de apomixis como un modo asexual de propagación en muchas especies, y se examinan los procesos, objetivos y perspectivas de su mejoramiento genético. Se definen claramente los criterios u objetivos genotécnicos deseables para la selección de materiales en los programas de mejoramiento genético de Rosa spp., todos ellos fundamentados en las necesidades cada vez más exigentes en la calidad de las rosas en el mercado comercial de la Floricultura. Varios autores ejemplifican y reportan los genes involucrados en la resistencia a enfermedades de importancia económica prioritaria, como la mancha negra del rosal, la cenicilla y el mildiú; en la floración recurrente, para asegurar la floración durante toda la estación; en la morfologÃa de la flor (multi-pétalas o flores dobles) para la comercialización de flores de corte y en la ausencia de espinas en las rosas de corte y en la maceterÃa. En los capÃtulos subsecuentes se revisan los avances biotecnológicos desarrollados en rosa, se describen las técnicas y metodologÃas empleadas actualmente como herramientas alternativas para el mejoramiento convencional, sus resultados y experiencias derivadas de la investigación cientÃfica, asà como sus usos potenciales y aplicaciones prácticas en áreas asociadas con la rápida propagación (acortamiento de los ciclos de germinación in vitro); cultivo de callos, anteras, polen; rescate de embriones (superando algunos de los problemas de esterilidad); embriogénesis somática; cultivo y fusión de protoplastos; mutagénesis in vitro; desarrollo de cultivares por medio de variación somaclonal; uso de marcadores moleculares y transformación genética. Para concluir la obra, se visualiza la biotecnologÃa en su conjunto (cultivo de tejidos, biologÃa celular y molecular, ingenierÃa genética) como un área de enormes oportunidades para desarrollar nuevos cultivares de rosa en respuesta a los cambios en la demanda de este producto ornamental, además se anexa un glosario de términos para facilitar su comprensión
Comparative study of the discriminating capacity of dna markers and their effectiveness in establishing genetic relationships in the genus tigridia
Tigridia Jussieu is an endemic genus to Mexico and taxonomically difficult with limited information about its genetic variability. A diversity assessment conducted using different DNA markers as an inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) markers will be helpful in the establishment of a broad- based description for improved germplasm curation and the identification of germplasm for genome mapping and breeding of these species. Thus, the objective of this study was to characterize 15 wild species of Tigridia by using RAPD and ISSR molecular markers. This study was carried out in the laboratory of Plant Molecular Biology at the Faculty of Agricultural Sciences of the Universidad Autónoma del Estado de México between August and November of 2011. In this assay, 13 RAPD primers of 10, 15 and 20 b, and five ISSR primers of the anchored type (ASSR) of 17 b were used to assess the level of genetic variation among 15 wild species of Tigridia . With both markers there were 163 amplified bands of which 150 (92.02 %) were polymorphic. The RAPD primers of 10 b generated 12 specific bands with a polymorphism of 95.12 %, for 15 b primers those values were five and 82.93 %, and for 20 b primers eight and 94.59 %, respectively. The RAPD pooled primers presented a polymorphism of 90.76 %, the genetic distance (G D ) among the species ranged from 0.16 (between T. illecebrosa and T. huajuapanensis ) to 0.57 (between T. multiflora and T. augusta ). The ISSR primers showed more polymorphism(95.45 %) than RAPD primers. With ASSR primers the highest genetic association (G D = 0.89) was observed between T. mexicana ssp. mexicana and T. durangense , whereas the least related were T. vanhouttei spp. vanhouttei and T. multiflora (G D = 0.14). This study shows that 10 base random primers and 17 base anchored primers were more efficient to detect polymorphism and genetic differentiation among Tigridia species
Cytogenetic relationships in three varieties of Tigridia pavonia (L.f.) DC
Background: Tigridia pavonia (L.f.) DC is a wild species with great ornamental value, of which nine plant varieties are known. Within the evolutionary process of this species, Penélope has been considered a natural hybrid, product of the cross between the varieties Trinidad and Dulce. Objective: In the present study, the cytogenetic relationships among Trinidad, Dulce and Penélope were analyzed. Methodology: The karyotype of the varieties Trinidad and Penélope was determined through classic cytogenetics and the physical mapping of the genes 5s and 45s rDNA through Fluorescent In Situ Hybridization. Results: The results showed for the first time the karyotype and the physical mapping of the genes 5s and 45s rDNA in the varieties Trinidad and Penélope. Implications: The information generated can be the basis for future evolutionary analyzes, and / or breeding programs in the species. Conclusion: A higher cytogenetic similarity of Penélope with Trinidad and Dulce has been revealed, suggesting that the latter may be the parents.Universidad Autónoma del Estado de Méxic
The effect of inositol, pyridoxina and thiamine on somatic embryogenesis of Agave angustifolia
ConacytBackground: Somatic embryogenesis in Agave angustifolia is an option for massive in vitro propagation and genetic improvement of this species, this process involves the induction of embryogenic callus, the development and maturation of embryos and their germination to form a complete plant. In this sense, an optimized selection of the compounds of the culture medium is required. Objective: This study evaluated the effect of vitamin components (inositol, pyridoxine and thiamine) on callus formation and induction of somatic embryos in A. angustifolia. Methodology: Two consecutive assays were conducted, assay I consisted of eight treatments to determine the isolated effect and in combination of three vitamin compounds (250.0 mg of L-1 inositol, 0.5 mg of L-1 pyridoxine and 2.0 mg of L-1 thiamine). In assay II the effect of six concentrations of thiamine (1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 mg L-1) was determined. In both assays, a completely randomized experimental design was used and each treatment had 20 repetitions. Results: The results of assay I show that the formulation of the vitamin complex of the culture medium plays a fundamental role in this process, suggesting that thiamine is an essential compound for the induction of somatic embryos (SE) of A. angustifolia because calluses obtained in thiamine supplemented media (alone or in combination) had a better embryogenic response than those not supplemented with this compound; In addition, in assay II with the increase in the concentration of thiamine to 2.5 and 3.0 mg L-1 in the culture medium, it is possible to induce a higher number of SE per explant (50.5 and 55.9, respectively), compared to 35.8 SE induced with the original concentration of thiamine (2.0 mg L-1). Implications: The results of this study contribute to a better understanding of the importance of the formulation of the vitamin complex and the effect of its addition in the culture medium to induce a greater number of SE in A. angustifolia. This can help in the beginning of programs of genetic improvement and ex situ conservation of this species. Conclusion: The results of this research suggest that thiamine is an essential compound for the acquisition of embryogenic potential in the somatic cells of A. angustifolia, since by increasing the concentration of this component in the culture medium it is possible to obtain a greater number of somatic embryos with high ex vitro survival rates.Universidad Autónoma del Estado de Méxic
Caracterización morfológica y molecular de nueve variedades botánicas de tigridia pavonia (l.f.) dc
Tigridia pavonia (L.f.) DC es una planta bulbosa nativa de México con potencial ornamental alto. México es considerado el centro de mayor diversidad de esta especie, por lo cual, el estudio de su diversidad genética y fenotÃpica es muy importante para establecer estrategias de manejo, conservación y utilización en programas de mejoramiento genético. El objetivo de este estudio fue caracterizar nueve variedades botánicas de Tigridia pavonia (L.f.) DC, con 21 marcadores morfológicos y cinco moleculares ISSR (Ãnter-Secuencias Simples Repetidas). Las variedades fueron recolectadas en tres municipios del Estado de México: Tenancingo (2100 m), Temascaltepec (2250 m) y Temoaya (2600 m). La distancia genética promedio para morfologÃa fue 0.54, mientras que para ISSR fue 0.49. AsÃ, ambos tipos de marcadores mostraron diversidad genética entre las variedades, distinguiendo a cada una de ellas. Los dendrogramas de los marcadores morfológicos e ISSR fueron notablemente similares, existiendo una correlación positiva entre ellos (R=0.30) y, en ambos casos, hubo una relación de las nueve variedades según su origen geográfico. Sin embargo, los marcadores ISSR fueron más efectivos, pues con un solo iniciador se distinguió a todas las variedades de T. pavonia. Se concluye que los marcadores ISSR son una herramienta útil para la discriminación rigurosa de genotipos y que se pueden usar de manera complementaria a la caracterización morfológica
COVID-19:Implications for the Support of People with Social Care Needs in England
This perspective examines the challenge posed by COVID-19 for social care services in England and describes responses to this challenge. People with social care needs experience increased risks of death and deteriorating physical and mental health with COVID-19. Social isolation introduced to reduce COVID-19 transmission may adversely affect well-being. While the need for social care rises, the ability of families and social care staff to provide support is reduced by illness and quarantine, implying reductions in staffing levels. Consequently, COVID-19 could seriously threaten care availability and quality. The government has sought volunteers to work in health and social care to help address the threat posed by staff shortages at a time of rising need, and the call has achieved an excellent response. The government has also removed some barriers to effective coordination between health and social care, while introducing measures to promote the financial viability of care providers. The pandemic presents unprecedented challenges that require well-co-coordinated responses across central and local government, health services, and non-government sectors
Recent GRBs observed with the 1.23m CAHA telescope and the status of its upgrade
We report on optical observations of Gamma-Ray Bursts (GRBs) followed up by
our collaboration with the 1.23m telescope located at the Calar Alto
observatory. The 1.23m telescope is an old facility, currently undergoing
upgrades to enable fully autonomous response to GRB alerts. We discuss the
current status of the control system upgrade of the 1.23m telescope. The
upgrade is being done by the ARAE our group, based on members of IAA (Instituto
de Astrofiisica de Andalucia). Currently the ARAE group is responsible to
develop the BOOTES network of robotic telescopes based on the Remote Telescope
System, 2nd Version (RTS2), which controls the available instruments and
interacts with the EPICS database of Calar Alto. Currently the telescope can
run fully autonomously or under observer supervision using RTS2. The fast
reaction response mode for GRB reaction (typically with response times below 3
minutes from the GRB onset) still needs some development and testing. The
telescope is usually operated in legacy interactive mode, with periods of
supervised autonomous runs under RTS2. We show the preliminary results of
several GRBs followed up with observer intervention during the testing phase of
the 1.23m control software upgrade.Comment: 15 pages, 7 figures. Accepted for publication in the Special issue
"Robotic Astronomy" of Advances in Astronomy. It includes two iterations with
the referee
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