555 research outputs found
Quadratic Maps in Two Variables on Arbitrary Fields
Let be a field of characteristic different from and , and
let be a vector space of dimension over . The generic
classification of homogeneous quadratic maps under the action
of the linear group of , is given and efficient computational criteria to
recognize equivalence are provided.Comment: 12 pages, no figure
Discerning the relationship between geminiviral infection and vesicle trafficking using virus induced gene silencing
Tomato yellow leaf curl disease is one of the most important threats to tomato crops worldwide. One of its causal agents, Tomato yellow leaf curl Sardinian virus (TYLCSV) is a monopartite member of the genus Begomovirus from the family Geminiviridae. Due to the few proteins encoded by their viral genome, geminiviruses rely heavily on host cellular machineries and interact with a wide range of plant proteins to complete all processes required for infection, such as viral replication, movement and suppression or evasion of plant defence mechanisms.
The identification of the host proteins involved in viral infection will be an important step towards the understanding of the mechanisms underlying this process. In our laboratory, transgenic Nicotiana benthamiana plants containing a green fluorescent protein (GFP) expression cassette flanked by two direct repeats of the intergenic region of TYLCSV have been constructed (2IR plants). When these plants are infected with TYLCSV, an overexpression of the reporter gene is observed in those cells where the virus is actively replicating. These plants have been used together with virus induced gene silencing (VIGS) in an effort to identify host genes involved in the infection process using a reverse genetics approach.
Using this combined technique our group has identified two genes δ-COP and ARF 1, involved in retrograde vesicle trafficking, which are essential for the infectious process. We are currently assaying genes codifying proteins involved in different pathways of the vesicle trafficking system: Sar1b, γ subunit of AP1, Sec24, SYT1 and two that encode the heavy chain of triskelion proteins. Their effect over viral infection will be presented and discussedUniversidad de Málaga. Campues de Excelencia Internacional Andalucía Tech
Identifying the function of vesicle trafficking in geminiviral infection using virus induced gene silencing
Tomato yellow leaf curl Sardinian virus (TYLCSV) is one of the causal agent of the tomato yel-low leaf curl disease, one of the most important threats to tomato crops worldwide. TYLCSV is a monopartite member of the genus Begomovirus from the family Geminiviridae. To carry out a full infection, geminiviruses need to move inside the infected cell and from one cell to an-other for which they depend on diverse cellular factors. While cell-to-cell movement has been described to occur through plasmodesmata, the way in which geminiviruses move inside the host cells is yet unknown.
The identification of the host proteins involved in viral infection will be an important step to-wards the understanding of the mechanisms underlying this process. In our laboratory, trans-genic Nicotianabenthamiana plants containing a green fluorescent protein (GFP) expression cassette flanked by two direct repeats of the intergenic region of TYLCSV have been construct-ed (2IR plants). When these plants are infected with TYLCSV, an overexpression of the reporter gene is observed in those cells where the virus replicates. These plants have been used to-gether with virus induced gene silencing (VIGS) in an effort to identify host genes involved in the infection process using a reverse genetics approach.
Using this combined technique our group has identified two genes δ-COP and ARF 1, involved in retrograde vesicle trafficking, which are essential for the infectious process. We are current-ly assaying genes codifying proteins involved in different pathways of the vesicle trafficking system: Sar1b, γ subunit of AP1, Sec24, SYT1 and two that encode the heavy chain of triskelion proteins. Their effect over virus infection will be presented and discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Importance of vesicle trafficking in the establichsment of a geminiviral infection
Importance of vesicle trafficking in the establishment of a geminiviral infection
P. CANA-QUIJADA1, T. ROSAS-DÍAZ2, LOZANO-DURÁN R. 2 AND E.R. BEJARANO1
1Dpto. Biología Celular, Genética y Fisiología. Área de Genética Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain E-mail: [email protected]
2. Shanghai Center for Plant Stress Biology (PSC), Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China.
INTRODUCTION
Geminiviruses produces some of the most devastating diseases for agriculture worldwide. Geminiviral genomes encode only 5 to 7 proteins, forcing them to rely heavily on host cellular machineries and to interact with a high amount of host proteins in order to complete a full infection. The identification of the host proteins involved in viral infection will be an important step towards the understanding of the mechanisms underlying this process and develop new strategies to generate new sources of resistance. Previous efforts from our group have identified several genes involved in vesicle trafficking.
OBJECTIVES
The main aim of this work is to elucidate the role of the plant cell’s vesicle trafficking in a geminiviral infection.
MATHERIALS AND METHODS
Transgenic Nicotiana benthamiana plants containing a green fluorescent protein (GFP) expression cassette flanked by two direct repeats of the intergenic region of TYLCSV have been constructed (2IR plants). When these plants are infected with TYLCSV, an overexpression of the reporter gene is observed in those cells where the virus is actively replicating.
2IR plants were used in combination with virus induced gene silencing (VIGS), to identify vesicle trafficking genes involved in the infectious process. Viral replication was monitorized by GFP expression. Viral accumulation was determined using qPCR.
RESULTS
When silenced, four of the assessed genes reduced dramatically the viral amounts or completely abolished the infection. On the other hand, three of them had no significant effect over the infection and one of them seems to cause a slight increase in viral accumulation.
CONCLUSIONS
The vesicle trafficking machinery plays an essential role in geminivirus infection. Assays to determine whether the described effect is due to a lack of replication or movement of the virus inside the plant cells are in progress.Universidad de Málaga. Campues de Excelencia Internacional Andalucía Tech
Geminivirus replication protein decreases PCNA sumoylation at two acceptor sites
Geminiviruses are plant viruses with circular, single-stranded DNA (ssDNA) genomes that infect a broad range of plants causing substantial crop diseases worldwide. They replicate in nuclei of infected cells by using host DNA replication machinery and an essential protein encoded in their genome designated Rep (replication-associated protein). This multifunctional protein induces the accumulation of the host factors involved in replication and it is capable of interacting with a lot of plant proteins including PCNA (Proliferating Cell Nuclear Antigen), a processivity factor that coordinates a wide range of processes involved in maintenance, duplication and transmission of the genome, and the sumoylation enzyme that conjugates SUMO to target proteins (SUMO-conjugating enzyme- SCE). PCNA modification by SUMO, and also ubiquitin, has long been known to be of key importance for determining how DNA damage is processed by the replisome and for maintenance of overall genome integrity. In yeast, PCNA sumoylation has been associated to DNA repair involving homologous recombination (HR). Previously, we reported that Rep ectopic expression does not result in broad changes in the sumoylation pattern of plant cells, but it modifies the sumoylation state of selected host proteins. In this work, we show, using a reconstituted sumoylation system in Escherichia coli, that tomato PCNA is sumoylated at two residues, K254 and K164, and that co-expression of the Rep protein suppresses PCNA sumoylation at these lysines. Finally, we confirm that PCNA is sumoylated and that Rep also interferes with PCNA sumoylation in planta.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Intervención nutricional en el paciente oncohematológico
Background: Oncohematological diseases such as
lymphoma or leukaemia affect an increasing number of
newly diagnosed patients in Spain and other countries.
Both disease and treatment may have a negatively impact
in the nutritional status of the patient. Malnutrition is not
uncommon among oncohematological patients. This
situation can compromised the course of the disease, the
clinical response of the treatment and the patient’s
quality of life.
Method: The implementation of a multidisciplinary
approach and a systematic and protocolled nutritional
assessment would be useful when dealing with haematological
malignancies.
Results: We present a proposal of protocol for nutritional
intervention in oncohematological patients. This
proposal is been developed from the analysis of the
published literature as well as clinical practice of a multidisciplinary
team specialized in the management of
patients with haematological malignanciesObjetivos: Las enfermedades oncohematológicas como
el Linfoma o la Leucemia afectan a un número importante
y creciente de personas en España. Tanto la enfermedad
como las distintas modalidades de tratamiento
que puede llegar a precisar el paciente a lo largo del curso
de la misma impactan negativamente en el estado nutricional
del paciente, no siendo infrecuente el desarrollo de
desnutrición, situación que compromete la evolución, la
respuesta al tratamiento y la calidad de vida del paciente.
Método: La implementación de una estrategia multidisciplinar,
sistematizada y protocolizada de valoración
nutricional puede resultar de utilidad a la hora de abordar
a los pacientes con enfermedades oncohematológicas.
Resultados: Se presenta una propuesta de protocolo de
evaluación y soporte nutricional en el paciente oncohematológico
elaborada a partir del análisis de la literatura
publicada al respecto, así como de la práctica clínica habitual
de un equipo sanitario multidisciplinar especialmente
implicado en el manejo de los pacientes con enfermedades
oncohematológica
Do UK universities communicate their brands effectively through their websites?
This paper attempts to explore the effectiveness of UK universities’ websites. The area of branding in higher education has received increasing academic investigation, but little work has researched how universities demonstrate their brand promises through their websites. The quest to differentiate through branding can be challenging in the university context, however. It is argued that those institutions that have a strong distinctive image will be in a better position to face a changing future. Employing a multistage methodology, the web pages of twenty UK universities were investigated by using a combination of content and multivariable analysis. Results indicated ‘traditional values’ such as teaching and research were often well communicated in terms of online brand but ‘emotional values’ like social responsibility and the universities’ environments were less consistently communicated, despite their increased topicality. It is therefore suggested that emotional values may offer a basis for possible future online differentiation
\b{eta}-delayed three-proton decay of 31Ar
The beta decay of 31Ar, produced by fragmentation of a 36Ar beam at 880
MeV/nucleon, was investigated. Identified ions of 31Ar were stopped in a
gaseous time projection chamber with optical readout allowing to record decay
events with emission of protons. In addition to \b{eta}-delayed emission of one
and two protons we have clearly observed the beta-delayed three-proton branch.
The branching ratio for this channel in 31Ar is found to be 0.07(2)%.Comment: 5 pages, 3 figures, submitted to Physical Rev.
Informing trait-based ecology by assessing remotely sensed functional diversity across a broad tropical temperature gradient
Spatially continuous data on functional diversity will improve our ability to predict global change impacts on ecosystem properties. We applied methods that combine imaging spectroscopy and foliar traits to estimate remotelysensed functional diversity in tropical forests across an Amazon-to-Andes elevation gradient (215 to 3537 m). We evaluated the scale dependency of community assembly processes and examined whether tropical forest productivitycould be predicted by remotely sensed functional diversity. Functional richness of the community decreased withincreasing elevation. Scale-dependent signals of trait convergence, consistent with environmental filtering, play animportant role in explaining the range of trait variation within each site and along elevation. Single- and multitraitremotely sensed measures of functional diversity were important predictors of variation in rates of net and grossprimary productivity. Our findings highlight the potential of remotely sensed functional diversity to inform trait-based ecology and trait diversity-ecosystem function linkages in hyperdiverse tropical forests.Fil: Durán, Sandra M.. University of Arizona; Estados UnidosFil: Martin, Roberta E.. Arizona State University; Estados UnidosFil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Maitner, Brian S.. Arizona State University; Estados UnidosFil: Malhi, Yadvinder. University of Oxford; Reino UnidoFil: Salinas, Norma. University of Oxford; Reino Unido. Pontificia Universidad Católica de Perú; PerúFil: Shenkin, Alexander. University of Oxford; Reino UnidoFil: Silman, Miles R.. Wake Forest University; Estados UnidosFil: Wieczynski, Daniel J.. University of Oxford; Reino UnidoFil: Asner, Gregory P.. Arizona State University; Estados UnidosFil: Bentley, Lisa Patrick. Sonoma State University; Estados UnidosFil: Savage, Van M.. University of California; Estados UnidosFil: Enquist, Brian J.. Arizona State University; Estados Unido
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