596 research outputs found
Analysis of genetic markers in a sample of uruguayan criollo horses
The aim of this work is to charaterize at least tentatively the Criollo Horses of Uruguay through blood genetic markers. This breed, whose origin goes back to horses brought to Rio de la Plata in 1538 from Spain, nowadays, after more than four centuries in its environment, owns unique zootechnical traits and well developed rusticity. We have studied 7 systems of blood groups (A, C, D, K, P, Q and U) and 6 of biochemical polymorphisms (A1B, Al, Tf, alk-Es, PGD, PGM) in a sample of 99 Criollo Horses of Uruguay. The most polymorphic loci were the D blood group system with 13 alleles, Ddelo, Dadl and Ddkl being the 3 most frequent ones, and the Tf locus, that displayed 7 alleles, D and F2 having the highest frequency. The genetic variability of the sample was estimated through the average heterozigosity that reached a value of 0.435. Concerning the origin of the breed, we have to stress the presence in our sample of TfJ and Dcfgk, breed allele markers of the Spanish Pure Breed Horse. We conclude from these results that the present days Criollo Horses of Uruguay have preserved some blood genetic traits of its ancestors that differentiate them from the other Criollo Horses, displaying at the same time an important amount of genetic variability as shown by the high value of average heterozigosity.En esta comunicación preliminar, presentamos la evaluación de las frecuencias alélicas obtenidas en 7 sistemas de grupos sanguíneos (A, C, D, K, P, Q y U) y 6 polimorfismos bioquímicos (A1B, Al, Es alcalina, Tf, PGD y PGM) en una muestra de 99 Caballos Criollos del Uruguay (CCU). Los sistemas más polimórficos fueron el sistema D, con 13 alelos siendo los más frecuentes: Ddelo, Dadl y Ddkl, y el locus Tf con 7 alelos siendo los más frecuentes: D y F2. Todos los sistemas electroforéticos se encontraron en equilibrio génico. La variabilidad genética de la muestra estudiada se estimó mediante el Índice de Heterocigosidad esperada, el cual presentó un valor de 0,435. En la muestra analizada se destaca la presencia de la variante TfJ y del alelo Dcfgk, marcadores característicos de la Pura Raza Española (PRE). Se puede concluir que estos datos proporcionan información de que los Caballos Criollos Uruguayos conservan parte del potencial genético de sus ancestros, manteniendo características propias y diferentes a la de las otros Caballos Criollos. En cuanto a la variabilidad genética, a pesar de ser una muestra pequeña, presentó un índice de heterocigosidad bastante alto
Genetic characterization of uruguayan creole cattle. II. Study of its genetic variability
Animal genetic diversity is considered essential to sustain the productivity of agriculture. FAO estimates that 30 percent of livestock breeds are at risk of extinction and more than half of these breeds are found in developing countries. Previous genetic research upon American Creole Cattle (Argentina, Colombia, Venezuela, Cuba) valuate these breeds, being considered of interest to maintain and enhance livestock production. In Uruguay, limited by different geographic barriers, about 600 bovines inhabit in hard environment in areas that cannot sustain conventional farming. Aspect of Uruguayan Creole cattle is similar to that observed in certain American and Iberian breeds. Analysis of breed genetic variability involved the utilization of PCR/RFLP technology in 82 DNA samples for milk proteins (casein and lactoglobulin), amplification of 20 samples for CYP21 microsatellite and the use of protein markers such as haemoglobin in 77 animals. Inbreeding index and expected Heterocigosity considering four loci were F= 0.02 and He= 0.487. Genotypic frequency distribution was in accordance with Hardy-Weinberg equilibrium. Genetic variation estimated, reinforced by the low inbreeding index, strengthen the need of preservation of Uruguayan Creole Cattle as a domestic animal genetic resource.Se tomaron muestras de ADN por la metodología PCR/RFLP para las proteínas de la leche caseína y lactoglobulina, 20 muestras para el microsatélite CYP21 (esteroide 21-hidroxilasa) y 77 animales para hemoglobina mediante electroforesis en gel de almidón. Los índices de endogamia y de heterocigosidad correspondieron a F= 0,02 y He= 0,487. Las frecuencias genotípicas se distribuyeron de acuerdo a los valores esperados para el equilibrio H.W. El bajo índice de endogamia obtenido en los 4 loci analizados, la relación entre el número de genotipos homocigotos y heterocigotos, el alto polimorfismo que presentó el microsatélite CYP21, así como la variabilidad observada en la coloración del pelaje, permiten sugerir que, a pesar de ser ésta una reserva aislada geográficamente, ha expresado una variabilidad genética tan importante que justifica su conservación como un recurso genético de animal doméstico. La diversidad genética animal es considerada indispensable para sostener la productividad de la agricultura. La FAO estima que el 30 p.100 de las razas de ganado, corren riesgo de extinción, encontrándose más de la mitad de ellas en países en desarrollo. Antecedentes de estudios genéticos realizados en bovinos Criollos americanos (Argentina, Colombia, Venezuela, Cuba) permiten hoy, revalorizar esta raza para ser utilizada en la explotación agropecuaria. En el Uruguay, existe una reserva de alrededor de 600 animales que habita en una zona húmeda, de sierras y montes, no alterada, limitada por diferentes barreras geográficas. El aspecto morfológico de estos animales se asemeja al de ciertas poblaciones de bovinos Criollos argentinos, venezolanos, colombianos y, a ciertas razas ibéricas. Con el objetivo de estudiar la estructura genética de esta población, se analizaron 8
L-Dopa modulates functional connectivity in striatal cognitive and motor networks: A double-blind placebo-controlled study
Functional connectivity (FC) analyses of resting-state fMRI data allow for the mapping of large-scale functional networks, and provide a novel means of examining the impact of dopaminergic challenge. Here, using a double-blind, placebo-controlled design, we examined the effect of L-dopa, a dopamine precursor, on striatal resting-state FC in 19 healthy young adults. We examined the FC of 6 striatal regions of interest (ROIs) previously shown to elicit networks known to be associated with motivational, cognitive and motor subdivisions of the caudate and putamen (Di Martino et al., 2008). In addition to replicating the previously demonstrated patterns of striatal FC, we observed robust effects of L-dopa. Specifically, L-dopa increased FC in motor pathways connecting the putamen ROIs with the cerebellum and brainstem. Although L-dopa also increased FC between the inferior ventral striatum and ventrolateral prefrontal cortex, it disrupted ventral striatal and dorsal caudate FC with the default mode network. These alterations in FC are consistent with studies that have demonstrated dopaminergic modulation of cognitive and motor striatal networks in healthy participants. Recent studies have demonstrated altered resting state FC in several conditions believed to be characterized by abnormal dopaminergic neurotransmission. Our findings suggest that the application of similar experimental pharmacological manipulations in such populations may further our understanding of the role of dopaminergic neurotransmission in those conditions
PcG Proteins, DNA Methylation, and Gene Repression by Chromatin Looping
Many DNA hypermethylated and epigenetically silenced genes in adult cancers are Polycomb group (PcG) marked in embryonic stem (ES) cells. We show that a large region upstream (∼30 kb) of and extending ∼60 kb around one such gene, GATA-4, is organized—in Tera-2 undifferentiated embryonic carcinoma (EC) cells—in a topologically complex multi-loop conformation that is formed by multiple internal long-range contact regions near areas enriched for EZH2, other PcG proteins, and the signature PcG histone mark, H3K27me3. Small interfering RNA (siRNA)–mediated depletion of EZH2 in undifferentiated Tera-2 cells leads to a significant reduction in the frequency of long-range associations at the GATA-4 locus, seemingly dependent on affecting the H3K27me3 enrichments around those chromatin regions, accompanied by a modest increase in GATA-4 transcription. The chromatin loops completely dissolve, accompanied by loss of PcG proteins and H3K27me3 marks, when Tera-2 cells receive differentiation signals which induce a ∼60-fold increase in GATA-4 expression. In colon cancer cells, however, the frequency of the long-range interactions are increased in a setting where GATA-4 has no basal transcription and the loops encompass multiple, abnormally DNA hypermethylated CpG islands, and the methyl-cytosine binding protein MBD2 is localized to these CpG islands, including ones near the gene promoter. Removing DNA methylation through genetic disruption of DNA methyltransferases (DKO cells) leads to loss of MBD2 occupancy and to a decrease in the frequency of long-range contacts, such that these now more resemble those in undifferentiated Tera-2 cells. Our findings reveal unexpected similarities in higher order chromatin conformation between stem/precursor cells and adult cancers. We also provide novel insight that PcG-occupied and H3K27me3-enriched regions can form chromatin loops and physically interact in cis around a single gene in mammalian cells. The loops associate with a poised, low transcription state in EC cells and, with the addition of DNA methylation, completely repressed transcription in adult cancer cells
Classical transport equation in non-commutative QED at high temperature
We show that the high temperature behavior of non-commutative QED may be
simply obtained from Boltzmann transport equations for classical particles. The
transport equation for the charge neutral particle is shown to be
characteristically different from that for the charged particle. These
equations correctly generate, for arbitrary values of the non-commutative
parameter theta, the leading, gauge independent hard thermal loops, arising
from the fermion and the gauge sectors. We briefly discuss the generating
functional of hard thermal amplitudes.Comment: 11 page
Integrating physiological data with the conservation and management of fishes: A meta-analytical review using the threatened green sturgeon (Acipenser medirostris)
Reversing global declines in the abundance and diversity of fishes is dependent on science-based conservation solutions. A wealth of data exist on the ecophysiological constraints of many fishes, but much of this information is underutilized in recovery plans due to a lack of synthesis. Here, we used the imperiled green sturgeon (Acipenser medirostris) as an example of how a quantitative synthesis of physiological data can inform conservation plans, identify knowledge gaps and direct future research actions. We reviewed and extracted metadata from peer-reviewed papers on green sturgeon. A total of 105 publications were identified, spanning multiple disciplines, with the primary focus being conservation physiology (23.8%). A meta-analytical approach was chosen to summarize the mean effects of prominent stressors (elevated temperatures, salinity, low food availability and contaminants) on several physiological traits (growth, thermal tolerance, swimming performance and heat shock protein expression). All examined stressors significantly impaired green sturgeon growth, and additional stressor-specific costs were documented. These findings were then used to suggest several management actions, such as mitigating salt intrusion in nursery habitats and maintaining water temperatures within optimal ranges during peak spawning periods. Key data gaps were also identified; research efforts have been biased towards juvenile (38.1%) and adult (35.2%) life-history stages, and less data are available for early life-history stages (embryonic, 11.4%; yolk-sac larvae, 12.4%; and post yolk-sac larvae, 16.2%). Similarly, most data were collected from single-stressor studies (91.4%) and there is an urgent need to understand interactions among stressors as anthropogenic change is multi-variate and dynamic. Collectively, these findings provide an example of how meta-analytic reviews are a powerful tool to inform management actions, with the end goal of maximizing conservation gains from research efforts
Transport equation for the photon Wigner operator in non-commutative QED
We derive an exact quantum equation of motion for the photon Wigner operator
in non-commutative QED, which is gauge covariant. In the classical
approximation, this reduces to a simple transport equation which describes the
hard thermal effects in this theory. As an example of the effectiveness of this
method we show that, to leading order, this equation generates in a direct way
the Green amplitudes calculated perturbatively in quantum field theory at high
temperature.Comment: 13 pages, twocolumn revtex4 styl
Inclusive electron scattering in a relativistic Green function approach
A relativistic Green function approach to the inclusive quasielastic (e,e')
scattering is presented. The single particle Green function is expanded in
terms of the eigenfunctions of the nonhermitian optical potential. This allows
one to treat final state interactions consistently in the inclusive and in the
exclusive reactions. Numerical results for the response functions and the cross
sections for different target nuclei and in a wide range of kinematics are
presented and discussed in comparison with experimental data.Comment: 12 pages, 7 figures, REVTeX
Assessment of an antibody-in-lymphocyte supernatant assay for the etiological diagnosis of pneumococcal pneumonia in children
New diagnostic tests for the etiology of childhood pneumonia are needed. We evaluated the antibody-in-lymphocyte supernatant (ALS) assay to detect immunoglobulin (Ig) G secretion from ex vivo peripheral blood mononuclear cell (PBMC) culture, as a potential diagnostic test for pneumococcal pneumonia. We enrolled 348 children with pneumonia admitted to Patan Hospital, Kathmandu, Nepal between December 2015 and September 2016. PBMCs sampled from participants were incubated for 48 h before harvesting of cell culture supernatant (ALS). We used a fluorescence-based multiplexed immunoassay to measure the concentration of IgG in ALS against five conserved pneumococcal protein antigens. Of children with pneumonia, 68 had a confirmed etiological diagnosis: 12 children had pneumococcal pneumonia (defined as blood or pleural fluid culture-confirmed; or plasma CRP concentration ≥60 mg/l and nasopharyngeal carriage of serotype 1 pneumococci), and 56 children had non-pneumococcal pneumonia. Children with non-pneumococcal pneumonia had either a bacterial pathogen isolated from blood (six children); or C-reactive protein <60 mg/l, absence of radiographic consolidation and detection of a pathogenic virus by multiplex PCR (respiratory syncytial virus, influenza viruses, or parainfluenza viruses; 23 children). Concentrations of ALS IgG to all five pneumococcal proteins were significantly higher in children with pneumococcal pneumonia than in children with non-pneumococcal pneumonia. The concentration of IgG in ALS to the best-performing antigen discriminated between children with pneumococcal and non-pneumococcal pneumonia with a sensitivity of 1.0 (95% CI 0.73–1.0), specificity of 0.66 (95% CI 0.52–0.78) and area under the receiver-operating characteristic curve (AUROCC) 0.85 (95% CI 0.75–0.94). Children with pneumococcal pneumonia were older than children with non-pneumococcal pneumonia (median 5.6 and 2.0 years, respectively, p < 0.001). When the analysis was limited to children ≥2 years of age, assay of IgG ALS to pneumococcal proteins was unable to discriminate between children with pneumococcal pneumonia and non-pneumococcal pneumonia (AUROCC 0.67, 95% CI 0.47–0.88). This method detected spontaneous secretion of IgG to pneumococcal protein antigens from cultured PBMCs. However, when stratified by age group, assay of IgG in ALS to pneumococcal proteins showed limited utility as a test to discriminate between pneumococcal and non-pneumococcal pneumonia in children
Mineralogical and geochemical influences on sediment color of Amazon wetlands analyzed by visible spectrophotometry
- …