4,293 research outputs found
Understanding the Evolutionary Relationships and Major Traits of \u3cem\u3eBacillus\u3c/em\u3e through Comparative Genomics
Background: The presence of Bacillus in very diverse environments reflects the versatile metabolic capabilities of a widely distributed genus. Traditional phylogenetic analysis based on limited gene sampling is not adequate for resolving the genus evolutionary relationships. By distinguishing between core and pan-genome, we determined the evolutionary and functional relationships of known Bacillus.
Results: Our analysis is based upon twenty complete and draft Bacillus genomes, including a newly sequenced Bacillus isolate from an aquatic environment that we report for the first time here. Using a core genome, we were able to determine the phylogeny of known Bacilli, including aquatic strains whose position in the phylogenetic tree could not be unambiguously determined in the past. Using the pan-genome from the sequenced Bacillus, we identified functional differences, such as carbohydrate utilization and genes involved in signal transduction, which distinguished the taxonomic groups. We also assessed the genetic architecture of the defining traits of Bacillus, such as sporulation and competence, and showed that less than one third of the B. subtilis genes are conserved across other Bacilli. Most variation was shown to occur in genes that are needed to respond to environmental cues, suggesting that Bacilli have genetically specialized to allow for the occupation of diverse habitats and niches.
Conclusions: The aquatic Bacilli are defined here for the first time as a group through the phylogenetic analysis of 814 genes that comprise the core genome. Our data distinguished between genomic components, especially core vs. pan-genome to provide insight into phylogeny and function that would otherwise be difficult to achieve. A phylogeny may mask the diversity of functions, which we tried to uncover in our approach. The diversity of sporulation and competence genes across the Bacilli was unexpected based on previous studies of the B. subtilis model alone. The challenge of uncovering the novelties and variations among genes of the non-subtilis groups still remains. This task will be best accomplished by directing efforts toward understanding phylogenetic groups with similar ecological niches
Tracking the Evolution of A Coherent Magnetic Flux Rope Continuously from the Inner to the Outer Corona
The magnetic flux rope (MFR) is believed to be the underlying magnetic
structure of coronal mass ejections (CMEs). However, it remains unclear how an
MFR evolves into and forms the multi-component structure of a CME. In this
paper, we perform a comprehensive study of an extreme-ultraviolet (EUV) MFR
eruption on 2013 May 22 by tracking its morphological evolution, studying its
kinematics, and quantifying its thermal property. As EUV brightenings begin,
the MFR starts to rise slowly and shows helical threads winding around an axis.
Meanwhile, cool filamentary materials descend spirally down to the
chromosphere. These features provide direct observational evidence of
intrinsically helical structure of the MFR. Through detailed kinematical
analysis, we find that the MFR evolution experiences two distinct phases: a
slow rise phase and an impulsive acceleration phase. We attribute the first
phase to the magnetic reconnection within the quasi-separatrix-layers
surrounding the MFR, and the much more energetic second phase to the fast
magnetic reconnection underneath the MFR. We suggest that the transition
between these two phases be caused by the torus instability. Moreover, we
identify that the MFR evolves smoothly into the outer corona and appears as a
coherent structure within the white light CME volume. The MFR in the outer
corona was enveloped by bright fronts that originated from plasma pile-up in
front of the expanding MFR. The fronts are also associated with the preceding
sheath region followed the outmost MFR-driven shock.Comment: 9 pages, 6 figures, and 1 table, accepted by ApJ; any comments are
welcome
Loss of redundant gene expression after polyploidization in plants
Based on chromosomal location data of genes encoding 28 biochemical systems in allohexaploid wheat,Triticum aestivum L. (genomes AABBDD), it is concluded that the proportions of systems controlled by triplicate, duplicate, and single loci are 57%, 25%, and 18% respectively
A unique Fock quantization for fields in non-stationary spacetimes
In curved spacetimes, the lack of criteria for the construction of a unique
quantization is a fundamental problem undermining the significance of the
predictions of quantum field theory. Inequivalent quantizations lead to
different physics. Recently, however, some uniqueness results have been
obtained for fields in non-stationary settings. In particular, for vacua that
are invariant under the background symmetries, a unitary implementation of the
classical evolution suffices to pick up a unique Fock quantization in the case
of Klein-Gordon fields with time-dependent mass, propagating in a static
spacetime whose spatial sections are three-spheres. In fact, the field equation
can be reinterpreted as describing the propagation in a
Friedmann-Robertson-Walker spacetime after a suitable scaling of the field by a
function of time. For this class of fields, we prove here an even stronger
result about the Fock quantization: the uniqueness persists when one allows for
linear time-dependent transformations of the field in order to account for a
scaling by background functions. In total, paying attention to the dynamics,
there exists a preferred choice of quantum field, and only one
-invariant Fock representation for it that respects the standard
probabilistic interpretation along the evolution. The result has relevant
implications e.g. in cosmology.Comment: Typos correcte
Derecho consuetudinario indĂgena : Dicotomia en lo procesal y en la práctica.
Anteriormente a la llegada de los españoles, el territorio ecuatoriano estaba conformado por distintos pueblos y nacionalidades indĂgenas originarios, los que nacieron y se desarrollaron en su propio territorio; tenĂan sus propias formas de organizaciĂłn social, actividad econĂłmica, ideologĂa polĂtica, normas de conductas, de convivencia social, costumbres y culturas, con la finalidad de construir una gran naciĂłn, quienes tenĂan un acervo diverso de conocimientos en astronomĂa, tĂ©cnicas agrĂcolas, medicina relacionada con las cualidades curativas de plantas y animales y un sistema de soluciĂłn de conflictos. Muchas de estas caracterĂsticas sociales han sobrevivido hasta nuestros dĂas con las particularidades propias de cada comunidad con sus tradiciones ancestrales.
Los estados que surgieron en el siglo XIX se constituyeron en la existencia de diversos grupos Ă©tnicos y culturales a quienes se les implanto la idiosincrasia de los blancos y los criollos, quienes por las estructuras del poder, conformaban grupos hegemĂłnicos. Dentro de este contexto reivindicativo de los pueblos indĂgenas, sus actores han iniciado una etapa de reconstituciĂłn e identificaciĂłn plena como colectividades diferenciadas. Es asĂ, que con la creaciĂłn de la ConfederaciĂłn de Nacionalidades IndĂgenas del Ecuador (CONAIE), en el año 1986, surge el concepto de nacionalidades y pueblos como una forma de sustituir tĂ©rminos peyorativos como Âżsalvajes, tribus, nativos, aborĂgenes, Ă©tnicos, minorĂas, entre otrosÂż, quienes a travĂ©s de grandes movilizaciones irrumpieron en la vida polĂtica del paĂs y a partir de entonces se convirtieron en el actor polĂtico más relevante del escenario social del Ecuador. En estos levantamientos sociales, los pueblos y nacionalidades indĂgenas que habitan en el territorio ecuatoriano, plantearon con el discurso Âżdistintos pero no igualesÂż la exigencia de que se los considere iguales ante la ley y en lo referente al disfrute de los derechos econĂłmicos y sociales, y de forma subsidiaria afirmaban su diferencia Ă©tnica, cultural y nacional. Una de las principales formas sociales que aun sobreviven dentro de las nacionalidades indĂgenas, es la aplicaciĂłn del derecho consuetudinario, el mismo que está reconocido constitucionalmente en nuestra Carta Magna, asĂ como en los instrumentos internacionales de los derechos fundamentales del hombre, en las que se otorga el ejercicio de funciones jurisdiccionales a las autoridades de las comunidades, pueblos y nacionales indĂgenas
A study of the recent chemical evolution of the Large Magellanic Cloud
Abstract: we present the results of a study of the Large Magellanic Cloud (LMC) chemical evolution during the last 2.2 Gyr. This study is based on Washington photometric observations of LMC's star clusters carried out with the Cerro Tololo Inter-American Observatory (CTIO) 4 m telescope, using the C and T_1 filters. As tracers of the LMC's chemical enrichment we used 83 star clusters, from which 40 clusters are projected onto the bar region, 23 in the inner disc and 20 in the outer disc. More than half of the total sample has not been previously studied. We determine size, reddening, deprojected distance, age and metallicity of the observed star clusters.Fil: Palma, Tali. Universidad Nacional de CĂłrdoba. Observatorio AstronĂłmico de CĂłrdoba; Argentina.Fil: Palma, Tali. Ministerio de Ciencia, TecnologĂa e InnovaciĂłn de la NaciĂłn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina.Fil: Clariá Olmedo, Juan JosĂ©. Universidad Nacional de CĂłrdoba. Observatorio AstronĂłmico de CĂłrdoba; Argentina.Fil: Clariá Olmedo, Juan JosĂ©. Ministerio de Ciencia, TecnologĂa e InnovaciĂłn de la NaciĂłn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina.Fil: Ahumada, Andrea. Universidad Nacional de CĂłrdoba. Observatorio AstronĂłmico de CĂłrdoba; Argentina.Fil: Ahumada, Andrea. Ministerio de Ciencia, TecnologĂa e InnovaciĂłn de la NaciĂłn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina.AstronomĂa (incluye AstrofĂsica y Ciencias del Espacio
Diseño y construcción de una máquina clasificadora y tamañadora de aceitunas.
En el sector olivĂcola de la provincia de Catamarca existĂa la demanda referida a máquinas
clasificadoras de aceitunas que se adaptaran a las necesidades o escalas de pequeños
productores; asimismo, tampoco habĂa quien satisficiera dicha demanda ya que no se contaba
con talleres metalĂşrgicos que se abocaran al desarrollo de estas tecnologĂas.
La demanda fue estimada a través de encuestas en el sector productivo realizadas por la Unión
Industrial Argentina, quien convocĂł para resolver esta situaciĂłn a potenciales oferentes.
Este proyecto se gesta con el propĂłsito de que ambas necesidades se sanearan a fin de incluir
innovaciones tecnológicas que acercaran soluciones prácticas a pequeños productores a partir
de capacitaciones en el sector oferente en cuanto a diseño y construcción de equipos similares
a medida de la escala que se requiera.
El equipo se ha desarrollado en dos mĂłdulos a) una cinta clasificadora sobre la que se
seleccionan los frutos aptos de los defectuosos y se desechan las impurezas en dos canales de
descarte; esta cinta, que se motoriza con un motoreductor de 0.5 hp, deposita las fruta sobre el
segundo módulo b) construido con sogas de 8 mm de diámetro que giran en un solo cuerpo
sobre cuatro cilindros de grilĂłn con canales separados a las distancias que se corresponde con
los diferentes calibres de aceitunas a separar, desde 12 mm a 37 mm, Ă©ste cuerpo de sogas se
motoriza con un motoreductor de 0.75 hp. En ambos mĂłdulos, se utiliza un variador de
velocidad integrado, que transforma la energĂa de trifásica a monofásica, lo que permite
instalar el sistema en cualquier domicilio independiente de la alimentaciĂłn de 380 voltios. Los
variadores de velocidad colocados en ambos mĂłdulos permiten disminuir o incrementar el
volumen a seleccionar; trabajando al mĂnimo de revoluciones el rendimiento es de 2000
Kg/hora. La totalidad del equipo fue revisada y aprobada por los organismos oficiales que
tienen la potestad sobre el tema.
Este proyecto culminĂł exitosamente con la entrega del equipo y las capacitaciones en buenas
prácticas agrĂcolas y en buenas prácticas de manufacturaa los integrantes del sector
demandante.publishedVersio
Phycomyces
This monographic review on a fungus is not addressed to mycologists. None of the authors has been trained or has otherwise acquired a general proficiency in mycology. They are motivated by a common interest in the performances of signal handling exhibited by the sense organs of all organisms and by the desire to attack these as yet totally obscure aspects of molecular biology by the study of a microorganism with certain desirable properties.
The sporangiophore of the fungus Phycomyces is a gigantic, single-celled, erect, cylindrical, aerial hypha. It is sensitive to at least four distinct stimuli: light, gravity, stretch, and some unknown stimulus by which it avoids solid objects. These stimuli control a common output, the growth rate, producing either temporal changes in growth rate or tropic responses.
We are interested in the output because it gives us information about the reception of the various signals. In the absence of external stimuli, the growth rate is controlled by internal signals keeping the network of biochemical processes in balance. The external stimuli interact with the internal signals. We wish to inquire into the early steps of this interaction. For light, for instance, the cell must have a receptor pigment as the first
mediator. What kind of a molecule is this pigment? Which organelle contains it? What chemical reaction happens after a light quantum has been absorbed? And how is the information introduced by this primary photochemical event amplified in a controlled manner and processed in the next step? How do a few quanta or a few molecules trigger macroscopic responses? Will we find ourselves confronted with devices wholly distinct from anything now known in biology
Impact of high-risk and low-risk human papillomavirus infections on the male genital tract: effects on semen inflammation and sperm quality
Human Papillomavirus (HPV), a prevalent sexually transmitted infection, comprises high-risk (HR-HPV) and low-risk (LR-HPV) viruses, the former posing a high risk for developing malignancies whereas the latter mainly for benign warts. Despite increasing awareness of HPV’s impact on men’s health, the influence of HR-HPV and LR-HPV urogenital infections on male fertility potential remains uncertain. This study aimed to investigate whether male urogenital infection with HR- or LR-HPV associates with impaired sperm quality, oxidative stress, and inflammation. A total of 205 male patients attending an urology clinic were enrolled. Semen samples were analyzed for HPV using PCR and genotyped by RFLP. Semen quality was evaluated following WHO guidelines. Semen leukocytes, reactive oxygen species (ROS), and sperm viability were analyzed using flow cytometry. HPV was detected in 19% (39/205) of semen samples. HR-HPV infections were more prevalent, with HPV-16 being the most frequent genotype. Neither HR-HPV nor LR-HPV were associated with significant alterations in routine sperm quality parameters. However, HR-HPV+ individuals showed significantly higher levels of sperm necrosis and exhibited increased proportions of ROS+ spermatozoa compared to LR-HPV+ or control individuals. Furthermore, no significant semen inflammation was detected in patients infected with either HR-HPV or LR-HPV, and unexpectedly reduced semen leukocytes and inflammatory cytokines (IL-6 and IL-1β) were observed in HR-HPV+ patients compared to controls. These observations underscore the importance of comprehensive HPV screening, including genotyping, in urology and fertility clinics to understand the progression of the infection, potential adverse effects on reproductive health, and the oncogenic risks involved.Fil: Olivera, Carolina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Paira, Daniela Andrea. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Olmedo, AndrĂ©s. Universidad Nacional de CĂłrdoba. Facultad de Medicina; ArgentinaFil: Olmedo, JosĂ© J.. Universidad Nacional de CĂłrdoba. Facultad de Medicina; ArgentinaFil: Tissera, Andrea D.. No especifĂca;Fil: Molina, Rosa I.. No especifĂca;Fil: Motrich, Ruben Dario. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Cuffini, Cecilia Gabriela. Universidad Nacional de CĂłrdoba. Facultad de Medicina. Instituto de VirologĂa Dr. J. M. Vanella; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba; ArgentinaFil: Rivero, Virginia Elena. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentin
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