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PIublicaciones
Tanto nuestro cuerpo docente como nuestros estudiantes contribuyen al conocimiento científico a través de sendas publicaciones en diversos tópicos de la Biología Molecular. He aquí algunas de las más recientes...
Transcriptome-based Phylogeny of the Semi-aquatic Bugs
(Hemiptera: Heteroptera: Gerromorpha) Reveals Patterns
of Lineage Expansion in a Series of New Adaptive Zones.
David armisén, Sévierin Viala, Isabell da Rocha Silva Cordiro, Antoinin Jean Hohan Crumière, Elisa Hendaoui, Agustin Le Bouquin, Wandrille Duchemin, Emilia Santos, William Toubiana, Aidamalia Vargas-Lowman, Carla Fernanda Burquez Floriano, Dan A. Polhemus, Yan-hui Wang, Locke Rowe, Felipe Ferráz Fegueiro Moreira y Abderrhman Khila.
Key innovations enable access to new adaptive zones and are often linked to increased species diversification. As such, innovations have attracted much attention, yet their concrete consequences on the subsequent evolutionary trajectory and diversification of the bearing lineages remain unclear. Water striders and relatives (Hemiptera: Heteroptera: Gerromorpha) represent a monophyletic lineage of insects that transitioned to live on the water–air interface and that diversified to occupy ponds, puddles, streams, mangroves and even oceans. This lineage offers an excellent model to study the patterns and processes underlying species diversification following the conquest of new adaptive zones. However, such studies require a reliable and comprehensive phylogeny of the infraorder.
Based on whole transcriptomic datasets of 97 species and fossil records, we reconstructed a new phylogeny of the Gerromorpha that resolved inconsistencies and uncovered strong support for previously unknown relationships between some important taxa. We then used this phylogeny to reconstruct the ancestral state of a set of adaptations associated with water surface invasion (fluid locomotion, dispersal and transition to saline waters) and sexual dimorphism.
Our results uncovered important patterns and dynamics of phenotypic evolution, revealing how the initial event of water surface invasion enabled multiple subsequent transitions to new adaptive zones on the water surfaces. This phylogeny and the associated transcriptomic datasets constitute highly valuable resources, making Gerromorpha an attractive model lineage to study phenotypic evolution.
Identificación Molecular del Alga Kappaphycus alvarezii cultivada en las Costas de la Provincia de Colón.
Nicolás Torrales y Claudia Massiel Pérez González
En Panamá, el cultivo de Kappaphycus se inició hace más de 20 años en la Provincia de Colón, generando ingresos económicos en las comunidades costeras de forma eco-sostenible. Estos cultivos a lo largo del tiempo experimentan diversos cambios generados por la interacción con el ambiente (contaminación, herbivoría, condiciones climáticas, etc.), influyendo en el fenotipo y genotipo de los cultivos de macroalgas, lo que muchas veces dificulta su correcta identificación taxonómica, caracterización y mantenimiento de las cepas que se cultivan, además que estas algas poseen una alta plasticidad fenotípica. Por tal razón, es necesario recurrir a las técnicas de identificación molecular de los cultivos para identificar y caracterizar molecularmente estas especies introducidas que tienen importancia comercial. En este estudio, el objetivo es identificar el cultivo de Kappaphycus en las Costas de la Provincia de Colón a través de marcadores moleculares.
Para ello, se utilizaron marcadores moleculares cloroplásticos como el rbcL y mitocondriales como el gen cox2-3. Como resultado se obtuvieron secuencias del gen mitocondrial cox 2-3, las cuales fueron sometidas a análisis filogenéticos junto a las secuencias depositadas en las bases de datos, dando como resultado que la especie cultivada corresponde a la especie Kappaphycus alvarezii y muestra cercanía con las especies de Kappaphycus y Eucheuma de Malasia.
Melanoma Progression Inhibits Pluripotency and Differentiation of
Melanoma-Derived iPSCs Produces Cells with Neural-like Mixed Dysplastic Phenotype
Edgardo Castro-Pérez, Carlos I. Rodríguez, Dareen Mikheil, Shakir Siddique, Alexandra McCarthy,
Michael A. Newton, and Vijayasaradhi Setaluri
Melanomas are known to exhibit phenotypic plasticity. However, the role cellular plasticity plays in melanoma tumor progression and drug resistance is not fully understood. Here, we used reprogramming of melanocytes and melanoma cells to induced pluripotent stem cell (iPSCs) to investigate the relationship between cellular plasticity and melanoma progression and mitogen-activated protein kinase (MAPK) inhibitor resistance. We found that melanocyte reprogramming is prevented by the expression of oncogenic BRAF, and in
melanoma cells harboring oncogenic BRAF and sensitive to MAPK inhibitors, reprogramming can be restored by inhibition of the activated oncogenic pathway. Our data also suggest that melanoma tumor progression acts as a barrier to reprogramming. Under conditions that promote melanocytic differentiation of fibroblast- and melanocyte-derived iPSCs, melanoma-derived iPSCs exhibited neural cell-like dysplasia and increased MAPK inhibitor resistance. These data suggest that iPSC-like reprogramming and drug resistance of differentiated cells can serve as a model to understand melanoma cell plasticity dependent mechanisms in recurrence of aggressive drug-resistant melanoma.oma, a lethal malignancy of pigment-producing melanocytes, manifests in a variety of clinico pathologically distinct and molecular subtypes in sun-exposed and nonsun-exposed areas.
Melanocytes, which are derived from multipotent neural crest, are present in diverse anatomical locations including eyes and various mucosal membranes. Melanocyte stem cells and melanocyte precursors are also present in other tissues. Elegant studies using genetic mouse models have shown that melanoma can arise from either melanocyte stem cells or differentiated melanocytes depending on the tissue context and oncogenic stimulus. This raises the possibility that different subtypes (and even subsets within each subtype) of human cutaneous melanoma may also reflect distinct cell of origin of these subtypes.
Interestingly, phenotypic plasticity, including transdifferention along with vascular and neural lineages, in a subset of human melanomas has been documented and stem cell–like gene expression has also been associated with development of melanoma drug resistance. In this context, reprogramming of melanoma cells to induced pluripotent stem cells (iPSCs) is proving to be a promising strategy to investigate cell or origin and phenotypic and molecular plasticity of human cutaneous melanoma. This chapter provides a comprehensive review of current state of knowledge and the promise of iPSC in unraveling cell of origin of melanoma and as a model to understand melanoma drug resistance mechanisms.
DNA barcoding as a tool for coral reef conservation
J. Neigel , A. Domingo, J. Stake
DNA Barcoding (DBC) is a method for taxonomic identiWcation of animals that is based entirely on the 5' portion of the mitochondrial gene, cytochrome oxidase subunit I (COI-5). It can be especially useful for identication of larval forms or incomplete specimens lacking diagnostic morphological characters. DBC can also facilitate the discovery of species and in deWning “molecular taxonomic units” in problematic groups. However, DBC is not a panacea for coral reef taxonomy. In two of the most ecologically important groups on coral reefs, the Anthozoa and Porifera, COI-5 sequences have diverged too little to be diagnostic for all species. Other problems for DBC include paraphyly in mitochondrial gene trees and lack of diferentiation between hybrids and their maternal ancestors. DBC also depends on the availability of databases of COI-5 sequences, which are still in early stages of development. A global eVort to barcode all Wsh species has demonstrated the importance of large-scale coordination and is yielding promising results. Whether or not COI-5 by itself is suficient for species assignments has become a contentious question; it is generally advantageous to use sequences from multiple loci.
Molecular Characterization of Pseudomonas aeruginosa
Clinical Isolates Among Patients of The Hospital del Niño,
Republic of Panama.
M Hernández, G Castillo, C Ciniglio, C Ramos, O Chen, B de Mayorga, O Durán, E González,
M González, C Aguilar, O Cisterna, M de Chial
The molecular characterization of 37 clinical isolates of P. aeruginosa obtained during September 2013 and September 2014 was conducted based on the 16S rDNA and oprL genes. The genetic diversity among isolates was determined with ERIC-pcr. The segments of the opr L and 16s rDNA genes were used to detect all P. aeruginosa isolates. The ERIC-PCR bands generated patterns that allowed the separation of isolates into different groups or clades and classify them into different genotypes.
The susceptibility pattern of the isolated strains against ceftazidime, imipenem, gentamicin and amikin was assessed by a disk diffusion method. The percentage of isolates resistant to ceftazidime, imipenem, gentamicin and amikin was 14%, 16%, 16% and 24% respectively. In general these percentages are relatively low compared to those reported in other countries and only one of the isolates (64113) showed multidrug resistance.