1,013 research outputs found
Aspergillus Section Flavi, Need for a Robust Taxonomy
In a recent letter to the editor, Houbraken et al. (23) provide a series of recommendations to the microbiological community to prevent the taxonomic misidentification of genome-sequenced fungal strains. In the era of genomics and bioinformatics, postulating that 1 nucleotide (nt) within a gene can “correctly” identify a species does not seem plausible. However, the authors of the letter call this the “calmodulin barcode,” meaning nucleotide substitutions within a 506-nt region of the calmodulin gene (1). After the evolutionarily conserved rRNA (18S rRNA, internal transcribed spacer [ITS], 28S rRNA) and RNA polymerase II (2–4) showed no differences between Aspergillus flavus S- and Lmorphotypes, attention shifted toward the calmodulin gene. Thus, without sequencing 18S rRNA, 28S rRNA, or the largest RNA polymerase II subunit, at least 34 new species of Aspergillus were named by Houbraken, Frisvad, Visagie, and coworkers (1, 5, 6). However, in a phylogenetic tree of 152 Aspergillus section Flavi isolates using the calmodulin 506- nt region, 40 Aspergillus minisclerotigenes isolates had only two nucleotide substitutions in common, namely, 100C.A and 269A.G, both of which are silent mutations (Fig. 1). However, only 269A.G discriminates A. minisclerotigenes from A. flavus, since 100C.A is present in three A. flavus isolates (GenBank accession numbers MK451387, MK451365, and MG517986) identified by the authors of the letter. We all agree that species identification is important; paradoxically, the calmodulin barcode assigns species based on a single-nucleotide polymorphism (SNP), while there are between 133,000 and 179,000 SNPs within A. flavus S- and L-morphotypes, respectively (7). Another limitation of Aspergillus taxonomy is the chemotypes resulting from 30 genes in the aflatoxin biosynthesis gene cluster (ABC) (8), e.g., A. flavus produces B-aflatoxins and Aspergillus parasiticus produces B and G types (9). Despite that a single nucleotide change in one ABC gene can prevent aflatoxin production (10), the inheritance of the ABC is favored by environmental pressure (11), and Aspergillus spp. are not physically or reproductively isolated; intraspecies and interspecies crosses can result in gain of function, e.g., G-type aflatoxin production (9, 12, 13). Hence, a new species named by one author of the letter was later reversed to its initial name by the same author because of the chemotype, i.e., A. flavus S-morphotype to Aspergillus parvisclerotigenus (14) and back to A. flavus (6). Other groups utilized the calmodulin gene and a single deletion in the ABC to name three new Aspergillus species (15, 16)
Microsatellite markers in Spanish lime (Melicoccus bijugatus Jacq., Sapindaceae), a neglected Neotropical fruit crop
Spanish lime (Melicoccus bijugatus Jacq.) is aNeotropical fruit tree cultivated, mainly, in orchards for self-consumption or local sale. The genus Melicoccus includes other nine species with edible fruits, some of these species are at risk of extinction. Like for the vast majority of tropical fruit trees, there is no information on the genetic diversity of Spanish lime and its related species, and this is mostly due to the lack of molecular markers. The objectives of this study were to present the first microsatellite markers developed for Spanish lime, testing its usefulness on a sample of cultivated accessions, as well as its transferability to Huaya India (M. oliviformis). To do this, we performed high-throughput sequencing of microsatellite-enriched libraries of Spanish lime using Roche 454, assembled 9567 DNA contig sequences and identified 10,117 microsatellites. After screening 384 of those microsatellites on four DNA samples, 31 polymorphic markers were used to screen 25 accessions of Spanish lime and five of Huaya India collected in Yucatan, Mexico. Genetic diversity was low in Spanish lime (A = 20.61, HE = 0.38) and similar for both sexes of this species. Neighbor-Joining and PCoA analyses clearly discriminated between the two Melicoccus species studied. Nine of the markers showed unique alleles for Huaya India. The set of microsatellite markers developed has a great potential to generate information in relation to conservation genetics, improvement of elite cultivars and breeding programs for Spanish lime and related species
Oxigenoterapia
La oxigenoterapia es la modalidad terapéutica más recomendable para el tratamiento de deficiencias de ventilación/perfusión, intercambio de gases e hipoventilación; por tanto, para la Fisioterapia Cardiopulmonar es de significativa importancia conocer su soporte conceptual y aplicación.
De acuerdo con lo anterior, se justifica la publicación del presente documento que hace una aproximación teórica de la oxigenoterapia, su definición, indicaciones, sistemas y formas de administración, prescripción, evaluación, cuidados generales y almacenamiento
Study of the genetic diversity of the aflatoxin biosynthesis cluster in \u3ci\u3eAspergillus\u3c/i\u3e section \u3ci\u3eFlavi\u3c/i\u3e using insertion/deletion markers in peanut seeds from Georgia, USA
Aflatoxins are among themost powerful carcinogens in nature. The major aflatoxin-producing fungi are Aspergillus flavus and A. parasiticus. Numerous crops, including peanut, are susceptible to aflatoxin contamination by these fungi. There has been an increased use of RNA interference (RNAi) technology to control phytopathogenic fungi in recent years. In order to develop molecular tools targeting specific genes of these fungi for the control of aflatoxins, it is necessary to obtain their genome sequences. Although high-throughput sequencing is readily available, it is still impractical to sequence the genome of every isolate. Thus, in this work, the authors proposed a workflow that allowed prescreening of 238 Aspergillus section Flavi isolates from peanut seeds from Georgia, USA. The aflatoxin biosynthesis cluster (ABC) of the isolates was fingerprinted at 25 InDel (insertion/deletion) loci using capillary electrophoresis. All isolates were tested for aflatoxins using ultra-high-performance liquid chromatography. The neighbor- joining, three-dimension (3D) principal coordinate, and Structure analyses revealed that the Aspergillus isolates sampled consisted of three main groups determined by their capability to produce aflatoxins. Group I comprised 10 non-aflatoxigenic A. flavus; Group II included A. parasiticus; and Group III includedmostly aflatoxigenic A. flavus and the three non-aflatoxigenic A. caelatus.Whole genomes of 10 representative isolates from different groups were sequenced. Although InDels in Aspergillus have been used by other research groups, this is the first time that the cluster analysis resulting from fingerprinting was followed by whole-genome sequencing of representative isolates. In our study, cluster analysis of ABC sequences validated the results obtained with fingerprinting. This shows that InDels used here can predict similarities at the genome level. Our results also revealed a relationship between groups and their capability to produce aflatoxins. The database generated of Aspergillus spp. can be used to select target genes and assess the effectiveness of RNAi technology to reduce aflatoxin contamination in peanut.
Supplementary file folder attached below
Caracteristicas reproductivas de ovejas Pelibuey sincronizadas e inducidas a la pubertad
El objetivo del experimento fue analizar las características reproductivas de ovejas Pelibuey sincronizadas (T1: n = 7) e inducidas a la pubertad (T2: n = 7). Las ovejas del T1 se presincronizaron, siete días después se aplicó a todas las ovejas FGA intravaginal durante 12 d y dos días antes de retirar el FGA se aplicó eCG. La incidencia de estro fue de 100 % en T1 y T2. El inicio del estro no fue diferente (P>0.05) con valores 21.4 ± 2.2 h y 24.2 ± 3.2 h para T1 y T2. La duración del estro fue de 60.5 ± 6.6 y 41.3 ± 3.6 para T1 y T2 (P<0.05). El inicio, duración y amplitud del pulso preovulatorio de LH no mostró diferencias con valores de 24.5 ± 1.7 y 24.2 ± 4.7 h, 13.4 ± 1.2 y 14.0 ± 0.6 h, 18.1 ± 2.7 y 21.3 ± 3.1 ng mL-1 para T1 y T2 respectivamente. La tasa de gestación no fue diferente con 100 y 85.71 % para T1 y T2. La tasa ovulatoria y prolificidad fue diferente (P<0.05) con valores de 4.4 ± 1.2 y 2.7 ± 0.4 y 2.5 ± 0.2 y 1.4 ± 0.4, para el T1 y T2 respectivamente. Se concluyó que el uso de FGA y eCG en ovejas Pelibuey es recomendable para inducir la pubertad, ya que las características reproductivas analizadas son aceptables, su implementación puede ser factible en programas de inseminación a tiempo fijo
En la costa aún sin mar
Los trabajos que conforman este volumen son una muestra de la presencia y actualidad de la obra de César Vallejo. Su poesía aún da lugar a nuevas y diversas interpretaciones; también a ciertas reconsideraciones. Asimismo, la narrativa del escritor peruano, poco atendida, está presente y exige estudio además de revalorización. La persona y obra de César Vallejo, en fin, son actuales incluso como un fenómeno metapoético.César Vallejo es un escritor esencial en el ámbito de la literatura contemporánea. Su obra literaria, escrita a principios del siglo pasado, sigue vigente. En su poesía, en particular, captó la sensibilidad de toda una época. Asimismo, supo traducir lo que él llamaba “el ritmo interior y el espíritu que se desprende de la realidad actual”. En cuanto a su obra en prosa, los estudios recientes dan muestra de su importancia, valor social y artístico. A casi cien años de la publicación de libros como Trilce y Los heraldos negros, la obra de César Vallejo sigue siendo fuente de goce estético y, por su complejidad, de búsqueda de conocimiento profundo de la realidad social y humana
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
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