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Aislamiento e identificación de genes de Opuntia streptacantha inducidos en condiciones de estrés abiótico

CLAUDIA OLIVIA SILVA ORTEGA (2008)

"Las temperaturas extremas junto con la sequía y la salinidad, constituyen los factores ambientales que más negativamente afectan el desarrollo de las plantas. El nopal (Opuntia spp.) ha desarrollado adaptaciones particulares que le permiten enfrentar las adversas condiciones climáticas de las zonas áridas y semiáridas y representa uno de los recursos de mayor potencial en el aprovechamiento de estas regiones en diversos países. El objetivo principal de la tesis fue aislar y caracterizar genes de nopal inducidos en condiciones de estrés hídrico y calor. Mediante una hibridación sustractiva (SSH) se obtuvieron 122 uni-genes potencialmente inducidos en cladodios de Opuntia streptacantha en estrés hídrico y a 40° C a los 13 días de tratamiento. El análisis de BLASTX mostró que aproximadamente el 78% de los uni-genes obtenidos presenta homología con genes de otras plantas, de los cuales el 9% han sido identificados en condiciones de estrés y el 18% son de función desconocida. Además los uni-genes obtenidos, para los cuales su función ha sido descrita, participan en diversos procesos metabólicos. Mediante análisis de RTPCR semi-cuantitativa confirmamos que 26 uni-genes son sobre-expresados en nopal en estrés hídrico y a 40° C a los 13 días, condiciones en las que se realizó la hibridación sustractiva. Adicionalmente aislamos una variante de procesamiento alternativo (retención de intrón) del uni-gen 27 que codifica para la subunidad alfa de la fosfofructocinasa dependiente de pirofosfato (Ostpdpk?1), expresado únicamente en condiciones de estrés hídrico y calor. Por otro lado obtuvimos la secuencia completa del cDNA de dos isoformas del factor de iniciación de la traducción (Ostsui1; uni-gen 13) mediante PCR inverso de una genoteca de cDNA completa de nopal, utilizando la información del EST de sui1. Además demostramos que el gen sui1 es diferencialmente expresado en diversas condiciones de estrés abiótico"

"Extreme temperatures, in conjunction with drought and salinity, constitute the major abiotic stresses affecting plant growth and development. Opuntia spp. has developed particular adaptations that allow to confront the adverse climatic conditions of the arid and semiarid zones and represents one of the resources of major potential in the development of these regions in diverse countries. The principal aim of this thesis was to isolate and to characterize genes of cactus pear induced in water and heat stress. By means of a subtractive hybridization we obtained 122 uni-genes potentially induced in Opuntia streptacantha young plants grown for 13 days under restricted water supply and high temperature (40° C). BLASTX analysis showed that approximately 78% of the uni-genes present homology with genes of other plants, of which 9% has been identified in stress conditions and 18% are of unknown function. Moreover the uni-genes for which its function has been described are involved in various metabolic processes. By RTPCR analyses we confirmed that 26 uni-genes are differentially expressed in Opuntia streptacantha under water and heat stress. Additionally we isolate a splicing variant (an intron retention) of the 27 uni-gene that codifies for the pyrophosphate-dependent phosphofructokinase alpha subunit (Ostpdpk?1) induced only in response to water and heat stress. On the other hand we obtained the full length cDNA sequence of two isoforms of the translation initiation factor (sui1; uni-gene 13) through a reverse PCR from a cDNA library of cactus pear, using the information from sui1 EST. In addition we demonstrated that sui1 is differentially expressed in various conditions of abiotic stress."

Doctoral thesis

ESTs Estrés abiótico Genes inducidos Líneas insercionales de Arabidopsis thaliana Opuntia streptacantha Prolina SSH BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA MOLECULAR BIOLOGÍA MOLECULAR

Genes and proteins associated with chemotherapeutic resistance in breast cancer

Rodolfo López Linares JONNATHAN GUADALUPE SANTILLAN BENITEZ ENRIQUE MORALES AVILA (2018)

Breast cancer is the main type of cancer that affects women in the world. Treatment with chemotherapeutic agents for this type of cancer depends to a large extent on the phenotypic characteristics that appear in the tumor, such as some receptors. The treatment of breast cancer is complex since not all patients respond adequately to it and this is partly due to mechanisms of resistance to treatment. The resistance either acquired or intrinsic to chemotherapeutics against breast cancer is related to multiple genes and proteins that are actively involved in the development of resistance mechanisms, which may be inhibiting the binding of the drug to the target receptor, inhibiting the gene expression of the receptors, activating signaling pathways, inducing the action of transporters that expel the drug from the cell, etc. As a result of this review, the mechanisms of chemotherapeutic resistance in breast cancer derived from genes and proteins related to say disease are described, including genes related to different types of breast cancer, as well as with different therapeutic strategies. These genes and their products of expression include a wide range of interactions and activations of signalling pathways that trigger a poor response to treatment, which translates into a worse prognosis, higher risk of prevalence and death, favouring breast cancer to be the main cause of cancer death in women. Objective: Conduct an updated review of genes and proteins, that have been associated with conferring resistance to the different chemotherapeutic agents used for the treatment of breast cancer, including the mechanism of resistance and the type of cancer in which it is generated. Method: The search for indexed articles in the PubMed (https://www.ncbi.nlm.nih.gov/pubmed/) and ScienceDirect (http://www.sciencedirect.com) databases was performed, using the words “Breast cancer resistance” as a search criterion, articles published in the period 2015-2017 were selected.

Article

breast cancer resistance proteins chemoterapeutics genes BIOLOGÍA Y QUÍMICA

Genome-wide association study reveals novel genomic regions for grain yield and yield-related traits in drought-stressed synthetic hexaploid wheat

Madhav Bhatta Alexey Morgounov Peter Stephen Baenziger (2018)

Synthetic hexaploid wheat (SHW; 2n = 6x = 42, AABBDD, Triticum aestivum L.) is produced from an interspecific cross between durum wheat (2n = 4x = 28, AABB, T. turgidum L.) and goat grass (2n = 2x = 14, DD, Aegilops tauschii Coss.) and is reported to have significant novel alleles-controlling biotic and abiotic stresses resistance. A genome-wide association study (GWAS) was conducted to unravel these loci [marker–trait associations (MTAs)] using 35,648 genotyping-by-sequencing-derived single nucleotide polymorphisms in 123 SHWs. We identified 90 novel MTAs (45, 11, and 34 on the A, B, and D genomes, respectively) and haplotype blocks associated with grain yield and yield-related traits including root traits under drought stress. The phenotypic variance explained by the MTAs ranged from 1.1% to 32.3%. Most of the MTAs (120 out of 194) identified were found in genes, and of these 45 MTAs were in genes annotated as having a potential role in drought stress. This result provides further evidence for the reliability of MTAs identified. The large number of MTAs (53) identified especially on the D-genome demonstrate the potential of SHWs for elucidating the genetic architecture of complex traits and provide an opportunity for further improvement of wheat under rapidly changing climatic conditions.

Article

Genomes Wheats Triticum aestivum Marker Trait Association Haplotype Block Root Traits D-genome Genotyping-by-Sequencing Single Nucleotide Polymorphism Complex Traits HARD WHEAT SOFT WHEAT GENES CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Transgenic strategies for enhancement of nematode resistance in plants

Muhammad Amjad Ali Abdelfattah DABABAT (2017)

Plant parasitic nematodes (PPNs) are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants.

Article

Plant nematodes Genes CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Combining three mapping strategies to reveal quantitative trait loci and candidate genes for maize ear length

jiafa chen (2018)

Ear length (EL) is an important trait in maize (Zea mays L.) because it is positively correlated with grain yield. To understand the genetic basis of natural EL variation, a F2:3, a four-way cross and a genome-wide association study (GWAS) population were used to identify the quantitative trait loci (QTLs) and candidate EL genes. Linkage mapping identified 14 QTLs in two types of populations from multiple environments. Six of them were located in three common genomic regions considered “stable QTLs”. Candidate genes for the three stable QTLs were identified by the GWAS results. These were related to auxin transport, cell proliferation, and developmental regulation. These results confirm that maize EL is under strong genetic control by many small-effect genes. They also improve our understanding of the genetic basis of maize EL.

Article

Quantitative Trait Loci Maize Genes AGRICULTURAL SCIENCES AND BIOTECHNOLOGY QUANTITATIVE TRAIT LOCI MAIZE GENES CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Genes que intervienen en la susceptibilidad individual a la apoptosis de las células germinales masculinas

NESTOR MENDEZ PALACIOS (2013)

El balance entre la proliferación y la muerte celular juega un papel fundamental en la producción de gametos. Al inicio de la espermatogénesis durante la pubertad se hace notoria la aparición de una ola de muerte por apoptosis de las células germinales en las que BAX promueve la muerte de las células germinales durante las etapas finales de diferenciación celular, sin embargo, la asociación de BAX con BCL-2 es clave para la supervivencia celular. Las hormonas esteroides también tienen un papel importante dentro de la espermatogénesis y la supervivencia celular. La pCA tiene un efecto de inhibición de la síntesis de serotonina, induciendo la apoptosis de las células germinales, sin embargo, la intensidad de la respuesta al fármaco, en términos de número de células muertas, varia de manera interindividual. En este trabajo, se identificaron aquellos genes cuya expresión pueda ser determinante de la susceptibilidad a la apoptosis de las células germinales, se utilizaron ratas machos de la cepa CII-ZV de 30 días de edad. Se formaron tres grupos: pCA, Vh y CA. Los animales se clasificaron conforme a la susceptibilidad a los eventos de muerte celular por apoptosis (baja o alta), posteriormente se identificó las diferencias en la expresión de los genes de interés. Las concentraciones de serotonina (ng/mg) fueron de 1.93±0.43 para el CA, 1.70±0.81 para el Vh y 0.86±0.05 para la pCA, esto comprueba la inhibición de la síntesis de la serotonina. La expresión de BAX y ABP fueron mayores en los individuos de alta susceptibilidad comparada con los individuos de baja susceptibilidad. La expresión de los genes AR, BCL-2, 3βHSD y CREMΔ fue similar entre los individuos con baja o alta susceptibilidad. No hubo cambios en las concentraciones de las hormonas gonadotropinas ni esteroides. El modelo de investigación propuesto sirvió para identificar a las ratas con alta o baja susceptibilidad a la apoptosis y ver la relación de los genes de apoptosis con esta susceptibilidad.

Doctoral thesis

genes apoptosis células germinales masculinas BIOLOGÍA Y QUÍMICA