1,063 research outputs found
Características hidráulicas y efecto del estrés hídrico en cuatro clones de Eucalyptus globulus Labill
Se estudió el efecto del déficit hídrico combinado
con altas temperaturas sobre la tasa de transpiración,
conductancia estomática y conductividad hidráulica
de tallo y raíces en planta de pequeño tamaño de
cuatro clones selectos de Eucalyptus globulus. Se
encontraron diferencias significativas entre clones en
los valores de la conductividad hidráulica de la parte
aérea por unidad de superficie foliar (Kshoot),
conductividad hidráulica específica (Ks) y
conductividad foliar (Kfoliar). Los menores valores
de Ks y Kfoliar se midieron en el clon que alcanzó el
menor crecimiento y menores valores de
conductancia estomática. El máximo crecimiento se
midió en el clon que alcanzó mayor valor de Kfoliar.
No se encontró una relación positiva entre los
valores de Kshoot y el crecimiento. El clon con
mayor sensibilidad estomática a las temperaturas
elevadas presentó valores altos de Kshoot, Ks y
Kfoliar. Este resultado demuestra que se debe
estudiar las “necesidades hidráulicas” de cada
genotipo para interpretar adecuadamente la relación
entre conductividad hidráulica, conductancia
estomática y tasa de transpiración.______________________________We examined the combined effect of water shortage
and high temperatures on the evapotranspiration
rate, stomatal conductance and hydraulic
conductivity of stems and roots in small-sized plants
of four selected Eucalyptus globulus clones and
found significant differences in hydraulic
conductivity of the aerial part per leaf area unit
(Kshoot), specific hydraulic conductivity (Ks) and leaf
conductivity (Kleaf) between clones. The smallest Ks
and Kleaf values were those for the clone exhibiting
the lowest growth and stomatal conduction. On the
other hand, the greatest Kleaf value was that for the
clone exhibiting the highest growth. No positive
correlation between Kshoot and growth was found in
any clone, however. The clone with the highest
stomatal sensitivity to high temperatures had large
Kshoot, Ks and Kleaf values. This result shows that
accurately interpreting the relationship between
hydraulic conductivity, stomatal conductance and
evapotranspiration in each genotype entails carefully
establishing its water requirements
How to Brush Your Way into the Bile Duct
info:eu-repo/semantics/publishedVersio
Decline in glutathione peroxidase and cytoplasmic catalases by lindane may cause an increase of reactive oxygen species in Saccharomyces cerevisiae
Lindane or gamma 1α,2α,3β,4α,5α,6β-hexachlorocyclohexane is an organochlorine insecticide, persistent in soils
and aquifers, lipophilic, chemically and biochemically inert that accumulates along the human food chain. It is
commonly used on a wide variety of crops, in warehouses, in public health to control insect-borne diseases, and
(with fungicides) as a seed treatment. Lindane is also presently used in lotions, creams, and shampoos for the
control of lice and mites (scabies) in humans. Several chemicals as lindane, toxic for aquatic organisms, birds
and mammals have been in the news recently, since the European Union intend to ban it. Therefore it is urgent to
clarify the toxicological mechanisms of this compound in eukaryotic cells. Thus the main purpose of this work
was to evaluate the effects of lindane in the wine wild-type Saccharomyces cerevisiae UE-ME3 of Alentejo
musts, Portugal, a unicellular eukaryotic organism, described as resistant to the presence of pesticides or metals.
Cells at mid-exponential phase were inoculated in YEPD medium with 2 % (w/v) glucose and incubated during
72 h in a water bath with orbital shaking, at 28 ºC, in the absence or in presence of 5 and 50 μM lindane. Samples
from each treatment were used to obtain growth curves, wet weight and to prepare post-12000 g supernatant,
used for determination of reactive oxygen species (ROS) [1] by fluorimetry and alkaline phosphatase (ALP) [2],
glutathione peroxidase (GPx) [3], selenium-dependent glutathione peroxidase (Se-GPx) [3] and cytoplasmic
catalase (CAT T) [4] activities as well as pellet for determination of peroxisomal catalase (CAT A) [4] activities
by spectrophotometry.
The results show that lindane inhibited cell growth of S. cerevisiae UE-ME3, causing a decrease in the biomass
produced along 72 h, as well as cell viability from 24 h of assay. On the other hand, was detected an increase in
the ROS content of post-12,000 g sediment of cells exposed to 5 μM lindane and post-12000 g supernatant of
cells subjected to any exposure conditions, eventually conditioned by a decline in GPx and CAT T activities,
which has become the detoxification of hydrogen peroxide less effective. The increase in the CAT A activity
without significant changes in the ALP and Se-GPx activities justified, in part, the increase in ROS levels of S.
cerevisiae exposed to lindane, as well as the loss of cell viability due to inadequate response of glutathione cycle
or cells signaling pathways that assure lipid biosynthesis
Fatty acid composition of Mytilus galloprovincialis larvae fed on different micoralgal diets: effect on larval growth and survival.
The influence of dietary essential fatty acid on bivalve larval growth and survival has been reported by several authors. The objectives of the current research were (1) to describe fatty acid composition of Mytilus galloprovincialis D-larvae and (2) to investigate the influence of algal lipid composition on larval growth and survival. Larvae were fed with two diets, A (Tetraselmis suecica + Isochrisis galbana) and B (Tetraselmis suecica + Chaetoceros sp). After fifteen days the larval growth was significantly higher with diet B than with diet A. The survival was also different, being 28% in diet A and 22.4 % in diet B. The percentages of veliger, pediveliger and amorphous larvae were higher in group A than in B, while in the latter there were not amorphous larvae and the 21 % were postlarvae. So, the microalgae Chaetoceros sp seems to enhance larvae growth and development. The difference in diet also produced changes in fatty acid profiles being the most important change ones (1) the increase of 14:0 in both groups, (2) 16:0 decreased in group A but it increased in group B and (3) total MUFA showed higher levels in both trials. Total PUFA n-6 level was higher in group A due to the 18:2n-6 increase. Arachidonic acid level was augmented with both diets. EPA level diminished in group A but it augmented in group B, DHA behaviour was opposite, increasing in group A but decreasing in group B. This is due to the high level of EPA in Chaetoceros sp and DHA in Isochrysis galbana (Fernández-Reiriz et al., 2006). These results do not coincide with other studies which suggest that DHA is a key requirement for larval development and growth of other bivalve species (Caers et al., 1999). In our case diet rich in EPA seems to be better in mussel larva culture than the diet rich in DHA. This work was supported by Interreg Project 0251_ECOAQUA_5_E, financed by the EDRF (European Regional Development Fund). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.
La influencia de la composición en ácidos grasos de la dieta ha sido estudiada por diversos autores. Los objetivos de este trabajo fuero (1) describir la composición en ácidos grasos de las larvas D de Mytilus galloprovincialis y (2) investigar la influencia de la composición lipídica de las microalgas en el crecimiento y supervivencia larvario. Las larvas se fueron alimentadas con dos dietas,A (Tetraselmis suecica + Isochrisis galbana) y B (Tetraselmis suecica + Chaetoceros sp). Tras quince días el crecimiento larvario fue significativamente mayor con la dieta B que con la dieta A. La supervivencia también fue diferente, siendo 28 % en la dieta A y 22.4% en la dieta B. El porcentaje de las larvas veliger, pediveliger y amorfas fue mayor en A que en B, mientras que en éste no hubo amorfas y el 21 % fueron postlarvas. Por lo tanto la microalga Chaetoceros sp mejora el cultivo larvario. La diferencia en la dieta también produjo cambios en el perfil de ácidos grasos siendo los más importantes (1) el incremento del 14:0 en ambos grupos, (2) el 16:0 decreció en el grupo A pero aumentó en el B y (3) el total de monoinsaturados mostró mayores valores en ambos grupos. El total de PUFA n-6 fue mayor en el grupo A debido al incremento de 18:2n-6. El nivel de ácido araquidónico aumentó en ambos grupos. El nivel de EPA disminuyó en el grupo A pero aumentó en el grupo B, el comportamiento del DHA fue el contrario, incrementando en el grupo A y disminuyendo en el B. Esto fue debido al alto nivel de EPA en Chaetoceros sp y DHA en Isochrysis galbana (Fernández-Reiriz et al., 2006). Estos resultados no coinciden con otros estudios que sugieren que el DHA es un requerimiento clave para el desarrollo y crecimiento larvarios de otras especies de bivalvos (Caers et al., 1999). En nuestro caso la dieta rica en EPA parece ser mejor para el cultivo larvario de mejillones que la dieta rica en DHA. Este trabajo fue apoyado por el proyecto Interreg 0251_ECOAQUA_5_E, financiado por el FEDER (Fondo Europeo de Desarrollo Regional). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.</p
On Hirschman and log-Sobolev inequalities in mu-deformed Segal-Bargmann analysis
We consider a deformation of Segal-Bargmann space and its transform. We study
L^p properties of this transform and obtain entropy-entropy inequalities
(Hirschman) and entropy-energy inequalities (log-Sobolev) that generalize the
corresponding known results in the undeformed theory.Comment: 42 pages, 3 figure
Optical-NIR spectroscopy of the puzzling gamma-ray source 3FGL 1603.9-4903/PMN J1603-4904 with X-shooter
The Fermi/LAT instrument has detected about two thousands Extragalactic High
Energy (E > 100 MeV) gamma-ray sources. One of the brightest is 3FGL
1603.9-4903, associated to the radio source PMN J1603-4904. Its nature is not
yet clear, it could be either a very peculiar BL Lac or a CSO (Compact
Symmetric Object) radio source, considered as the early stage of a radio
galaxy. The latter, if confirmed, would be the first detection in gamma-rays
for this class of objects. Recently a redshift z=0.18 +/- 0.01 has been claimed
on the basis of the detection of a single X-ray line at 5.44 +/- 0.05 keV
interpreted as a 6.4 keV (rest frame) fluorescent line. We aim to investigate
the nature of 3FGL 1603.9-4903/PMN J1603-4904 using optical to NIR
spectroscopy. We observed PMN J1603-4904 with the UV-NIR VLT/X-shooter
spectrograph for two hours. We extracted spectra in the VIS and NIR range that
we calibrated in flux and corrected for telluric absorption and we
systematically searched for absorption and emission features. The source was
detected starting from ~6300 Ang down to 24000 Ang with an intensity comparable
to the one of its 2MASS counterpart and a mostly featureless spectrum. The
continuum lacks absorption features and thus is non-stellar in origin and
likely non-thermal. On top of this spectrum we detected three emission lines
that we interpret as the Halpha-[NII] complex, the [SII] 6716,6731 doublet and
the [SIII] 9530 line, obtaining a redshift estimate of z= 0.2321 +/- 0.0004.
The equivalent width of the Halpha-[NII] complex implies that PMN J1603-4904
does not follow the observational definition of BL Lac, the line ratios suggest
that a LINER/Seyfert nucleus is powering the emission. This new redshift
measurement implies that the X-ray line previously detected should be
interpreted as a 6.7 keV line which is very peculiar.Comment: Published in Astronomy and Astrophysic
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