707 research outputs found
Revising the diversity within the Dwarf Dog-faced Bat, Molossops temminckii (Chiroptera, Molossidae), with the revalidation of the endangered Molossops griseiventer
The genus Molossops includes two monotypic species of insectivore bats distributed in South America: Molossops neglectus and Molossops temminckii. Both can be differentiated, based on sizes, M. temminckii being smaller (forearm less than 33 mm). Despite being monotypic, at least two additional subspecies have been described for M. temminckii, of which M. temminckii griseiventer from the inter-Andean Valley of the Magdalena River in Colombia might represent a valid taxon. To test the taxonomic status of M. t. griseiventer, we reviewed specimens of M. temminckii from cis- and trans-Andean localities in Colombia. We used Cytochrome-b and Cytochrome Oxidase I comparisons to test the phylogenetic position of cis- and trans-Andean samples and compared qualitative morphology, morphometric and bioacoustics. Our results show that M. t. griseiventer is differentiated from cis-Andean specimens, providing further evidence of its validity at the species level. Furthermore, M. temminckii (sensu stricto) is also distributed in Colombia, but both M. griseiventer and M. temminckii are allopatric, with the Andes acting as a barrier. The specific identity of the specimens from the Caribbean Region of Colombia needs a new evaluation, but our results clearly show that the diversity of Molossops is underestimated
Global mRNA expression analysis in myosin II deficient strains of Saccharomyces cerevisiae reveals an impairment of cell integrity functions
<p>Abstract</p> <p>Background</p> <p>The <it>Saccharomyces cerevisiae MYO1 </it>gene encodes the myosin II heavy chain (Myo1p), a protein required for normal cytokinesis in budding yeast. Myo1p deficiency in yeast (<it>myo1Δ</it>) causes a cell separation defect characterized by the formation of attached cells, yet it also causes abnormal budding patterns, formation of enlarged and elongated cells, increased osmotic sensitivity, delocalized chitin deposition, increased chitin synthesis, and hypersensitivity to the chitin synthase III inhibitor Nikkomycin Z. To determine how differential expression of genes is related to these diverse cell wall phenotypes, we analyzed the global mRNA expression profile of <it>myo1Δ </it>strains.</p> <p>Results</p> <p>Global mRNA expression profiles of <it>myo1Δ </it>strains and their corresponding wild type controls were obtained by hybridization to yeast oligonucleotide microarrays. Results for selected genes were confirmed by real time RT-PCR. A total of 547 differentially expressed genes (p ≤ 0.01) were identified with 263 up regulated and 284 down regulated genes in the <it>myo1Δ </it>strains. Gene set enrichment analysis revealed the significant over-representation of genes in the protein biosynthesis and stress response categories. The <it>SLT2/MPK1 </it>gene was up regulated in the microarray, and a <it>myo1Δslt2Δ </it>double mutant was non-viable. Overexpression of ribosomal protein genes <it>RPL30 </it>and <it>RPS31 </it>suppressed the hypersensitivity to Nikkomycin Z and increased the levels of phosphorylated Slt2p in <it>myo1Δ </it>strains. Increased levels of phosphorylated Slt2p were also observed in wild type strains under these conditions.</p> <p>Conclusion</p> <p>Following this analysis of global mRNA expression in yeast <it>myo1Δ </it>strains, we conclude that 547 genes were differentially regulated in <it>myo1Δ </it>strains and that the stress response and protein biosynthesis gene categories were coordinately regulated in this mutant. The <it>SLT2/MPK1 </it>gene was confirmed to be essential for <it>myo1Δ </it>strain viability, supporting that the up regulated stress response genes are regulated by the <it>PKC1 </it>cell integrity pathway. Suppression of Nikkomycin Z hypersensitivity together with Slt2p phosphorylation was caused by the overexpression of ribosomal protein genes <it>RPL30 </it>and <it>RPS31</it>. These ribosomal protein mRNAs were down regulated in the <it>myo1Δ </it>arrays, suggesting that down regulation of ribosomal biogenesis may affect cell integrity in <it>myo1Δ </it>strains.</p
Efectos inmunológicos de la vitamina D en COVID-19
El sÃndrome respiratorio severo o grave causado por el nuevo coronavirus (SARS-CoV-2) es una enfermedad de gran auge en la actualidad, que se ha propagado vertiginosamente a lo largo de los 5 continentes, siendo Norteamérica y algunos paÃses europeos como Italia, España y Francia los más afectados por esta pandemia. En la actualidad, no se cuenta con una estrategia de prevención o tratamiento que logre mitigar de forma contundente las cifras de infectados y muertos a nivel mundial; sin embargo, se están estudiando alternativas que podrÃan impactar de forma positiva en el curso de la enfermedad.
El déficit de 25 hidroxivitamina D (25OH D) ha mostrado ser un factor independiente de mortalidad por todas las causas, principalmente en enfermedades cardiovasculares y cáncer. La suplementación de esta también se ha asociado a beneficios en la prevención de enfermedades respiratorias; para el caso de la COVID-19, los mecanismos por los cuales la vitamina D podrÃa ser útil para el tratamiento y la prevención se resumen en la actividad sobre las barreras fÃsicas y la inmunidad natural celular y adaptativa, que disminuye la probabilidad de tormenta de citocinas.
Algunos estudios realizados concluyeron que el pico de la infección por SARS-CoV-2 se presentó durante el invierno, tiempo donde los niveles de 25OH D son más bajos; además, estos niveles subóptimos se han relacionado con aumento en la incidencia de complicaciones tales como falla cardÃaca, sepsis y progresión a sÃndrome de dificultad respiratoria del adulto (SDRA) y, por consiguiente, con un aumento en las tasas de mortalidad, lo cual respalda el papel de la vitamina D en la modificación del curso natural de la enfermedad. Sin embargo, también se prendieron las alarmas, ya que se ha demostrado una prevalencia alta de hipovitaminosis D en Bogotá, Villavicencio, Neiva, Barranquilla y MedellÃn, que podrÃa exponer a la población colombiana a resultados adversos. La evidencia indica que la suplementación con vitamina D modula y reduce el riesgo de infección por SARS-CoV-2, pero se precisan más estudios para corroborar los efectos benéficos en la población
DETERMINACIÓN DE LA RENTABILIDAD DE LA PRODUCCIÓN DE OVINOS RAZA PELIBUEY EN EL NORTE DE SONORA
The feeding and the shelter are considered basic needs of the man and one of the options to satisfy them is through the lambs which contribute to cover them with their meat, wool and skin. For the analysis of the yield a flock took itself from twenty females and a stallion one of Pelibuey race and was developed in conditions of semiestabulado and artificial prairie with oats and rye grass in the north of the State of Sonora.Several indicators were taken to carry out the determination of the yield taking in first instance the capital of work, point of balance, sensitivity analysis as well as the relation benefit-cost. In the case of first the amount of 109.650,44 like so was determined whereas the balance point obtains as of the second period of 270 days showing little sensitivity the changes of the sale price of the young since the ninety percent of them is realised like registry cattle and the rest to commercial prices and; the relation benefit-cost was of 1.98. These indicators show that the growing and operation of lambs under these conditions reveals an acceptable yield for the producers.Lambs, yield, capital of work, analysis, benefit-cost., Agribusiness,
Radial and axial variation of fiber and vessel element length in <i>Nothofagus nervosa</i> (Nothofagaceae) of Patagonia Argentina
El objetivo del presente trabajo fue caracterizar las fibras y los elementos de vaso en madera de Nothofagus nervosa (Phil.) Dim. et Mil., Nothofagaceae, (raulÃ), determinando la variación de sus longitudes dentro del árbol, en sentido radial y axial, y evaluando la variabilidad entre árboles. Se trabajó con cuatro árboles de DAP superior a 40 cm, del sitio Quilanlahue, Neuquén, Argentina, de los cuales se extrajeron rodajas a tres alturas distintas. Se utilizó el radio de orientación norte de cada una de ellas, realizándose preparados microscópicos y macerados cada diez años desde la médula a la corteza. Se describieron las caracterÃsticas de fibras y elementos de vaso. La longitud de ambos tipos celulares aumentó de manera significativa en sentido radial de médula a corteza. En sentido axial la longitud de fibras aumenta, mientras que la longitud de elementos de vaso no evidencia cambios significativos. La mayor fuente de variación se presentó dentro del árbol, relacionada con las diferentes edades formativas del leño. Se observó una disminución del coeficiente de variación para la longitud de fibras y elementos de vaso a partir de los veinte años de edad del árbol. La variabilidad entre árboles no fue significativa.The goal of this paper was to characterize fibers and vessel elements in the wood of Nothofagus nervosa (Phil.) Dim. et Mil., Nothofagaceae, (raulÃ), determining the variation of their lengths in the tree in radial and axial orientations and evaluating their variability between trees. Four trees with DBH (diameter at breast height) above 40 cm were used from Quilanlahue site, Neuquén, Argentina, from which sections were removed at three different heights. The north radius of each section was used and microscopic preparations and macerations were produced every ten years from pith to bark. The characteristics of fibers and vessel elements were described. The length of both cells was significantly greater in radial orientation from pith to bark. In axial orientation the length of the fiber is variable, while the length of vessel elements does not show significant changes. The greatest source of variation was observed in the tree related to the different ages at which wood was formed. A diminishing in the variation coefficient was observed for the length of fibers and vascular elements from twenty years of age of the tree. Variability among trees was not significant.Facultad de Ciencias Agrarias y Forestale
Topoisomerase II beta interacts with cohesin and CTCF at topological domain borders
BACKGROUND:
Type II DNA topoisomerases (TOP2) regulate DNA topology by generating transient double stranded breaks during replication and transcription. Topoisomerase II beta (TOP2B) facilitates rapid gene expression and functions at the later stages of development and differentiation. To gain new insight into the genome biology of TOP2B, we used proteomics (BioID), chromatin immunoprecipitation, and high-throughput chromosome conformation capture (Hi-C) to identify novel proximal TOP2B protein interactions and characterize the genomic landscape of TOP2B binding at base pair resolution.
RESULTS:
Our human TOP2B proximal protein interaction network included members of the cohesin complex and nucleolar proteins associated with rDNA biology. TOP2B associates with DNase I hypersensitivity sites, allele-specific transcription factor (TF) binding, and evolutionarily conserved TF binding sites on the mouse genome. Approximately half of all CTCF/cohesion-bound regions coincided with TOP2B binding. Base pair resolution ChIP-exo mapping of TOP2B, CTCF, and cohesin sites revealed a striking structural ordering of these proteins along the genome relative to the CTCF motif. These ordered TOP2B-CTCF-cohesin sites flank the boundaries of topologically associating domains (TADs) with TOP2B positioned externally and cohesin internally to the domain loop.
CONCLUSIONS:
TOP2B is positioned to solve topological problems at diverse cis-regulatory elements and its occupancy is a highly ordered and prevalent feature of CTCF/cohesin binding sites that flank TADs
- …