495 research outputs found
Optimized exploitation of aquifers: application to the Querenca-Silves aquifer system
A great deal of optimization models have been developed to support aquifer planning and management with the goal of arriving at the best decisions in relation to the number and siting of infrastructures to be built and how to operate them. A mixed-integer multi-objective linear model has been taken from the literature to define the best decision for the development of the aquifer of Querenca-Silves (Portugal). It identifies efficient solutions for the location and design of pumping stations and their catchment area to supply a given number of demand centers, without disregarding the effect of groundwater management on the piezometric surface of aquifers and the many facets of groundwater management. The multi-objective model includes two objectives: (1) the minimization of aggregate water elevation height, and (2) the minimization of aggregate water transport length, weighted by the flows conveyed from the facilities to the centers. The effect of groundwater extraction on the piezometric surface of the aquifer is modelled with a response matrix method, with the establishment of maximum drawdown to prevent over-exploitation
Rapeseed oil-rich diet alters in vitro menadione and nimesulide hepatic mitochondrial toxicity
Diet-induced changes in the lipid composition of mitochondrial membranes have been shown to influence
physiological processes. However, the modulation effect of diet on mitochondrially-active drugs
has not yet received the deserved attention. Our hypothesis is that modulation of membrane dynamics
by diet impacts drug-effects on liver mitochondrial functioning. In a previous work, we have shown that
a diet rich in rapeseed oil altered mitochondrial membrane composition and bioenergetics in Wistar rats.
In the present work, we investigated the influence of the modified diet on hepatic mitochondrial activity
of two drugs, menadione and nimesulide, and FCCP, a classic protonophore, was used for comparison. The
results showed that the effects of menadione and nimesulide were less severe on liver mitochondria for
rats fed the modified diet than on rats fed the control diet. A specific effect on complex I seemed to be
involved in drug-induced mitochondria dysfunction. Liver mitochondria from the modified diet group
were more susceptible to nimesulide effects on MPT induction. The present work demonstrates that diet
manipulation aimed at modifying mitochondrial membrane properties alters the toxicity of mitochondria
active agents. This work highlights that diet may potentiate mitochondrial pharmacologic effects or
increase drug-induced liabilities.The project was supported by the Foundation for Science and
Technology (FCT, Portugal) with FEDER/COMPETE/National Budget
funds (research grants PTDC/QUI-QUI/101409/2008 to P.J.O.,
PTDC/QUI-BIQ/103001/2008 to A.S.J. and PEst-C/SAU/LA0001/
2013-2014 to the CNC). J.P.M. and A.M.S acknowledge FCT for
Ph.D. grants SFRH/BD/37626/2007 and PTDC/AGR-ALI/108326/
2008 respectively
Impact of Carvedilol on the Mitochondrial Damage Induced by Hypoxanthine and Xantine Oxidase - What Role in Myocardial Ischemia and Reperfusion?
Objectivo: Os efeitos cardioprotectores do
carvedilol (CV) poderão ser explicados, em
parte, por interacções ao nível da
mitocôndria cardíaca. O objectivo deste
trabalho visou o estudo do efeito protector do
CV em mitocôndrias cardíacas durante danos
oxidativos induzidos por hipoxantina e
xantina oxidase (HX/XO), uma conhecida
fonte de estresse oxidativo no sistema
cardiovascular.
Métodos: As mitocôndrias foram isoladas a
partir de corações de ratos Wistar (n=8) e
incubadas com o par HX/XO, na presença e
na ausência de cálcio. Vários métodos foram
utilizados de modo a verificar a acção
protectora do CV: avaliação das alterações de
volume mitocondrial (variação da densidade
óptica da suspensão mitocondrial), tomada e
libertação de cálcio mitocondrial (com uma
sonda fluorescente, Calcium Green-5N) e
respiração mitocondrial (com um eléctrodo
de oxigénio).
Resultados: O CV reduziu os danos
mitocondriais associados à produção de
espécies reactivas de oxigénio (ERO) pelos
prooxidantes, como verificado pela redução
no entumescimento mitocondrial e aumento
da capacidade de retenção do cálcio pela
mitocôndria. O CV melhorou ainda a
capacidade respiratória mitocondrial associada ao estado fosforilativo e aumentou
o índice de controlo respiratório (p<0.05) e o
quociente ADP/O (p<0.001) das
mitocôndrias cardíacas sob estresse oxidativo
induzido por HX/XO.
Conclusões: Os dados indicam que o CV
protegeu parcialmente a mitocôndria
cardíaca de danos oxidativos induzidos por
HX/XO, o que poderá ser de grande
utilidade em situações de isquémiareperfusão
do miocárdio.
Os resultados também sugerem que a
mitocôndria poderá ser um alvo prioritário
para a acção benéfica de alguns fármacos
cardioprotectores.Objectives: The cardioprotective effects of
carvedilol (CV) may be explained in part by
interactions with heart mitochondria. The
objective of this work was to study the
protection afforded by CV against oxidative
stress induced in isolated heart mitochondria
by hypoxanthine and xanthine oxidase
(HX/XO), a well-known source of reactive
oxygen species (ROS) in the cardiovascular
system.
Methods: Mitochondria were isolated from
Wistar rat hearts (n=8) and incubated with
HX/XO in the presence and in the absence of
calcium. Several methods were used to assess
the protection afforded by CV: evaluation of
mitochondrial volume changes (by measuring
changes in the optical density of the
mitochondrial suspension), calcium uptake
and release (with a fluorescent probe, Calcium
Green 5-N) and mitochondrial respiration
(with a Clark-type oxygen electrode).
Results: CV decreased mitochondrial damage
associated with ROS production by HX and
XO, as verified by the reduction of mitochondrial swelling and increase in
mitochondrial calcium uptake. In the
presence of HX and XO, CV also
ameliorated mitochondrial respiration in the
active phosphorylation state and prevented
decrease in the respiratory control ratio
(p<0.05) and in mitochondrial
phosphorylative efficiency (p<0.001).
Conclusions: The data indicate that CV
partly protected heart mitochondria from
oxidative damage induced by HX and XO,
which may be useful during myocardial
ischemia and reperfusion. It is also
suggested that mitochondria may be a
priority target for the protective action of
some compounds
Collembolan morphospecies (Hexapoda: Collembola) in serpentine soils: a case study in a natural ecosystem in northeastern Portugal
Serpentine soils represent challenging habitats for plants and soil dwelling organisms, such as collembolans, because they typically exhibit high levels of heavy metals (e.g. chromium, cobalt, and nickel). Serpentinized areas cover about 8000 ha in Northeastern Portugal. While the plant communities are well studied, the collembolans are virtually unknown. The data presented here represent the first effort to describe the structure of a collembolan community, using morphospecies as a surrogate of species, in a serpentinized area occupied by a natural forest of Quercus rotundifolia and Quercus faginea located nearby Bragança (Portugal). Sampling was performed during the last week of September of 2008 in a serpentinized area near Bragança (Portugal). At each of the 29 sampling points (distributed along two transects) collembolans were collected with a soil core (5 cm diameter x 10 cm depth). The collembolans were extracted from the soil (using a McFadyen apparatus), sorted, counted and finally identified to morphospecies level. The number of morphospecies observed was 37. The total abundance in the mineral horizon (1862 individuals) was not significantly different from the organic horizon (1883 individuals). The Simpson Diversity Index and Richness were higher in the organic horizon (21.7 and 35 species, respectively) than in the mineral horizon (9.9 and 30 species, respectively). The species accumulation curves showed that the estimated number of morphospecies for the mineral horizon is 36 while for the organic horizon is 38
Carvedilol: Relation Between Antioxidant Activity and Inhibition of the Mitochondrial Permeability Transition
Objectivos: A transição de permeabilidade
mitocondrial (TPM) é um evento associado a
estresse oxidativo severo (por exemplo,
durante isquémia e reperfusão do miocárdio)
e acumulação excessiva de cálcio
mitocondrial, podendo mesmo levar a morte
celular. Neste estudo comparou-se o efeito
do Carvedilol (CV) na TPM cardíaca
induzida por cálcio/fosfato (Ca/Pi) e
cálcio/carboxiatractilato (Ca/Catr). Para a
indução da TPM por Ca/Pi, o estresse
oxidativo tem um papel importante, levando
a oxidação de grupos tiólicos proteicos
mitocondriais, em contraste com o efeito do
Ca/Catr, onde essa oxidação é secundária à
indução da TPM e não é motivada por
estresse oxidativo.
Materiais e métodos: As mitocôndrias foram
isoladas a partir do coração de rato e
avaliaram-se parâmetros relacionados com a
indução da TPM (n=5 para cada indutor):
entumescimento mitocondrial e oxidação dos
grupos tiólicos proteicos (ambos por
espectrofotometria).
Resultados: Com Ca/Pi, o CV protegeu a
mitocôndria da indução da TPM,
nomeadamente na sua forma deletéria de alta
condutância. Este efeito evidenciou-se pela
diminuição do entumescimento mitocondrial.
Este efeito foi simultâneo com a inibição da
oxidação dos grupos tiólicos proteicos carmitocondriais
(p<0.001). O CV não mostrou
efeitos protectores com Ca/Catr.
Conclusões: O CV protegeu a mitocôndria
cardíaca da TPM, mas apenas quando a
oxidação dos grupos tiólicos proteicos foi
causa e não consequência da TPM. Estes
resultados mostram claramente que, durante
agressões ao miocárdio (durante a
isquémia/reperfusão, por exemplo), o efeito
protector do CV é primariamente devido a
um efeito antioxidante, inibindo a produção
e os efeitos das espécies reactivas de
oxigénio.Objectives: The mitochondrial permeability
transition (MPT) is an event related to severe
oxidative stress (for example, during
myocardial ischemia and reperfusion) and
excessive mitochondrial calcium
accumulation, also being implicated in cell
death. In this study, we compared the effect
of carvedilol on the cardiac MPT induced by
calcium and phosphate (Ca/Pi) and
calcium/carboxyatractyloside (Ca/Catr).
Oxidative stress plays a major role in MPT
induction by Ca/Pi, leading to the oxidation
of protein thiol groups, in contrast with
Ca/Catr, where such oxidation is secondary
to MPT induction and is not caused by
oxidative stress.
Materials and methods: Mitochondria were
isolated from rat hearts and parameters
related to MPT induction were evaluated
(n=5 for each inducer): mitochondrial
swelling and oxidation of protein thiol groups
(both measured by spectrophotometry).
Results: Using Ca/Pi, carvedilol protected
mitochondria from MPT induction,
particularly in its high conductance form. Its
effect was demonstrated by analyzing the
decrease in mitochondrial swelling
amplitude. Simultaneously, we observed inhibition of protein thiol group oxidation
(p<0.001). By contrast, carvedilol did not
show any protective effect with Ca/Catr.
Conclusions: Carvedilol was only effective
against the MPT when the oxidation of
protein thiol groups was the cause and not
the consequence of the MPT phenomenon.
The results clearly show that during
myocardial aggressions (ischemia and
reperfusion, for example), the protective
effect of carvedilol is primarily due to an
antioxidant mechanism, inhibiting the
production and effects of reactive oxygen
species
The chemistry and structure of calcium (alumina) silicate hydrate: A study by XANES, ptychographic imaging, and wide- and small-angle scattering
Collembolan communities in a sustainable system for production of woody biomass for energy: abundance and diversity of morphospecies.
Woody biomass for energy obtained from short rotation woody crops (SRWC) needs to be managed in a sustainable way, thus allowing ecosystem conservation. However, there is a gap in our knowledge concerning the effects of these crops on soil organisms, of which collembolans represent a good indicator of soil quality. On the other hand, soil biological sciences are strongly affected by the taxonomic skill crisis, with many groups of soil animals suffering from a taxonomic impediment in terms of identification. This problem can be reduced by using a para-taxonomic approach where morphospecies can be used as surrogates of taxonomic species. The objective of this work was to study the structure of collembolan communities in a SRWC experimental field using morphospecies. Abundance, richness, evenness and diversity indexes were used to describe the structure of the collembolan community and species accumulation curves were computed to estimate species richness in the study area. Prior to the installation of the SRWC, 106 soil samples were collected at each defined sampling point (distributed along 14 transects) using a soil core (5 cm diameter x 10 cm depth). In the laboratory, collembolans were extracted from the soil (using a McFadyen apparatus), sorted, counted and finally identified to morphospecies level. The number of morphospecies observed was 34, representing a total abundance of 3221 collembolans. The Simpson Diversity Index and richness were 27and 34, respectively. The species accumulation curves showed that the estimated number of morphospecies was 38
Monitoring ground arthropods in maize and pasture fields of São Miguel and São Jorge Islands: IPM-Popillia Project.
ABSTRACT: The dataset presented here is the delivery of the European project “Integrated Pest Management of the Invasive Japanese Beetle, Popillia japonica (IPM-Popillia)”. This project aims to address the challenge of a new risk to plant health in Europe, the invasion of the Japanese beetle, Popillia japonica, and to provide an environmentally friendly IPM-Toolbox to control the pest in infested areas, protecting the agricultural systems and control this pest populations current in expansion across Europe. The present study targets to record, in maize and pasture fields of the Azores, ground arthropods with the potential to be used in futures Integrated Pest Management programs against P. japonica. A sampling program was conducted in two Islands (São Miguel and São Jorge) in the summer of 2022.info:eu-repo/semantics/publishedVersio
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