Involvement of L-type calcium channel and SERCA2a in myocardial dysfunction induced by obesity

Obesity has been shown to impair myocardial performance. Nevertheless, the mechanisms underlying the participation of calcium (Ca(2+)) handling on cardiac dysfunction in obesity models remain unknown. L-type Ca(2+) channels and sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2a), may contribute to the cardiac dysfunction induced by obesity. The purpose of this study was to investigate whether myocardial dysfunction in obese rats is related to decreased activity and/or expression of L-type Ca(2+) channels and SERCA2a. Male 30-day-old Wistar rats were fed standard (C) and alternately four palatable high-fat diets (Ob) for 15 weeks. Obesity was determined by adiposity index and comorbidities were evaluated. Myocardial function was evaluated in isolated left ventricle papillary muscles under basal conditions and after inotropic and lusitropic maneuvers. L-type Ca(2+) channels and SERCA2a activity were determined using specific blockers, while changes in the amount of channels were evaluated by Western blot analysis. Phospholamban (PLB) protein expression and the SERCA2a/PLB ratio were also determined. Compared with C rats, the Ob rats had increased body fat, adiposity index and several comorbidities. The Ob muscles developed similar baseline data, but myocardial responsiveness to post-rest contraction stimulus and increased extracellular Ca(2+) was compromised. The diltiazem promoted higher inhibition on developed tension in obese rats. In addition, there were no changes in the L-type Ca(2+) channel protein content and SERCA2a behavior (activity and expression). In conclusion, the myocardial dysfunction caused by obesity is related to L-type Ca(2+) channel activity impairment without significant changes in SERCA2a expression and function as well as L-type Ca(2+) protein levels. J. Cell. Physiol. 226: 2934-2942, 2011. (C) 2011 Wiley-Liss, Inc.

Moderate exercise training decreases aortic superoxide production in myocardial infarcted rats

Myocardial infarction (MI) has been associated with increases in reactive oxygen species (ROS). Exercise training (ET) has been shown to exert positive modulations on vascular function and the purpose of the present study was to investigate the effect of moderate ET on the aortic superoxide production index, NAD(P)H oxidase activity, superoxide dismutase activity and vasomotor response in MI rats. Aerobic ET was performed during 11 weeks. Myocardial infarction significantly diminished maximal exercise capacity, and increased vasoconstrictory response to norepinephrine, which was related to the increased activity of NAD(P)H oxidase and basal superoxide production. On the other hand, ET normalized the superoxide production mostly due to decreased NAD(P)H oxidase activity, although a minor SOD effect may also be present. These adaptations were paralleled by normalization in the vasoconstrictory response to norepinephrine. Thus, diminished ROS production seems to be an important mechanism by which ET mediates its beneficial vascular effects in the MI condition.

Repeated disturbances and canopy disturbance regime in a tropical semi-deciduous forest

The canopy disturbance regime and the influence of gap methods on the interpretation of forest structure and dynamics were evaluated in a tropical semi-deciduous forest in south-eastern Brazil. We encountered a gap density of 11.2 gaps ha(-1) and an average size which varied from 121 to 333 m(2) depending on the gap delimitation method considered (minimum gap size was 10 m(2)). Although average size was slightly higher, the median value obtained (78 m(2)) was comparable to other tropical forest sites and the gap size-class distribution found supported the pattern described for such forest sites. Among 297 gap makers, snapping and uprooting were the most common modes of disturbance. The number and basal area of gap makers were good predictors of gap size. Almost 25% of all gaps suffered from repeated disturbance events that brought about larger gap sizes. Such processes, along with delimitation methods, strongly influenced the estimation of turnover rate and therefore the interpretation of forest dynamics. These results demonstrated the importance of further studies on repeated disturbances, which is often neglected in forest studies.

Large Woody Debris Input and Its Influence on Channel Structure in Agricultural Lands of Southeast Brazil

Riparian forests are important for the structure and functioning of stream ecosystems, providing structural components such as large woody debris (LWD). Changes in these forests will cause modifications in the LWD input to streams, affecting their structure. In order to assess the influence of riparian forests changes in LWD supply, 15 catchments (third and fourth order) with riparian forests at different conservation levels were selected for sampling. In each catchment we quantified the abundance, volume and diameter of LWD in stream channels; the number, area and volume of pools formed by LWD and basal area and tree diameter of riparian forest. We found that riparian forests were at a secondary successional stage with predominantly young trees (diameter at breast height < 10 cm) in all studied streams. Results showed that basal area and diameter of riparian forest differed between the stream groups (forested and non-forested), but tree density did not differ between groups. Differences were also observed in LWD abundance, volume, frequency of LWD pools with subunits and area and volume of LWD pools. LWD diameter, LWD that form pools diameter and frequency of LWD pools without subunits did not differ between stream groups. Regression analyses showed that LWD abundance and volume, and frequency of LWD pools (with and without subunits) were positively related with the proportion of riparian forest. LWD diameter was not correlated to riparian tree diameter. The frequency of LWD pools was correlated to the abundance and volume of LWD, but characteristics of these pools (area and volume) were not correlated to the diameter of LWD that formed the pools. These results show that alterations in riparian forest cause modifications in the LWD abundance and volume in the stream channel, affecting mainly the structural complexity of these ecosystems (reduction in the number and structural characteristics of LWD pools). Our results also demonstrate that riparian forest conservation actions must consider not only its extension, but also successional stage to guarantee the quantity and quality of LWD necessary to enable the structuring of stream channels.

An estimate of biometric parameters in eucalyptus clone plantations in Southern Bahia: an application of the airborne laser scanning (ALS) technology

The application of airborne laser scanning (ALS) technologies in forest inventories has shown great potential to improve the efficiency of forest planning activities. Precise estimates, fast assessment and relatively low complexity can explain the good results in terms of efficiency. The evolution of GPS and inertial measurement technologies, as well as the observed lower assessment costs when these technologies are applied to large scale studies, can explain the increasing dissemination of ALS technologies. The observed good quality of results can be expressed by estimates of volumes and basal area with estimated error below the level of 8.4%, depending on the size of sampled area, the quantity of laser pulses per square meter and the number of control plots. This paper analyzes the potential of an ALS assessment to produce certain forest inventory statistics in plantations of cloned Eucalyptus spp with precision equal of superior to conventional methods. The statistics of interest in this case were: volume, basal area, mean height and dominant trees mean height. The ALS flight for data assessment covered two strips of approximately 2 by 20 Km, in which clouds of points were sampled in circular plots with a radius of 13 m. Plots were sampled in different parts of the strips to cover different stand ages. The clouds of points generated by the ALS assessment: overall height mean, standard error, five percentiles (height under which we can find 10%, 30%, 50%,70% and 90% of the ALS points above ground level in the cloud), and density of points above ground level in each percentile were calculated. The ALS statistics were used in regression models to estimate mean diameter, mean height, mean height of dominant trees, basal area and volume. Conventional forest inventory sample plots provided real data. For volume, an exploratory assessment involving different combinations of ALS statistics allowed for the definition of the most promising relationships and fitting tests based on well known forest biometric models. The models based on ALS statistics that produced the best results involved: the 30% percentile to estimate mean diameter (R(2)=0,88 and MQE%=0,0004); the 10% and 90% percentiles to estimate mean height (R(2)=0,94 and MQE%=0,0003); the 90% percentile to estimate dominant height (R(2)=0,96 and MQE%=0,0003); the 10% percentile and mean height of ALS points to estimate basal area (R(2)=0,92 and MQE%=0,0016); and, to estimate volume, age and the 30% and 90% percentiles (R(2)=0,95 MQE%=0,002). Among the tested forest biometric models, the best fits were provided by the modified Schumacher using age and the 90% percentile, modified Clutter using age, mean height of ALS points and the 70% percentile, and modified Buckman using age, mean height of ALS points and the 10% percentile.

Distribution of Aceria guerreronis and Neoseiulus baraki among and within coconut bunches in northeast Brazil

Aceria guerreronis Keifer (Acari: Eriophyidae) is considered a major pest of coconut in many countries in the Americas, Africa and parts of Asia. Neoseiulus baraki Athias-Henriot (Acari: Phytoseiidae) is one of the predatory mites most commonly found in association with A. guerreronis in parts of northeast Brazil. The objective of this work was to study the distribution of A. guerreronis and N. baraki among and within coconut bunches. The hypothesis was tested that A. guerreronis and N. baraki are homogenously distributed over the fruits in a bunch, independent of the fruits` age and position. Five collections of bunches, each corresponding to leaves 12-16 from apex (about 2-6 month-old), were conducted in each of three fields in northeastern Brazil, from February to October, 2007. A total of 1,986 fruits were examined. The number of mites, the percentage of fruits hosting them and the level of damage caused by A. guerreronis were evaluated. The highest density of A. guerreronis was observed on fruits of bunch 4 whereas the highest density of N. baraki was observed on bunch 5. Considering all fruits together, no significant differences were observed between densities of either A. guerreronis or N. baraki among the basal, median and apical thirds of the bunches. In younger bunches, fruits of the apical region tend to have lower densities of both mites than fruits of the basal region. This pattern, in association with a similar pattern for the percentage of fruits hosting N. baraki, suggests that the predator initially reaches the basal bunch region, from where it moves to the apical region. The results of the present study suggest that the pest population reduction in bunches older than bunch 4 could be due to (1) an effect of the predator, (2) reduction of the proportion of undamaged tissues amenable to attack, and/or (3) less favorable characteristics of the fruits to attack by A. guerreronis, as indicated by their increasing lignin content as they get older.

Effect of Calcium on the in vitro Growth of Aechmea blanchetiana (Baker) L. B. Smith Plantlets

This work investigated the influence of different concentrations of calcium on the growth of plantlets of the bromeliad Aechmea blanchetiana cultured in vitro. Seedlings of A. blanchetiana were axenically cultured in liquid Murashige and Skoog basal medium supplemented with different concentrations of calcium (Ca; 1.5, 3, 4.5, 6, or 12 mM) without growth regulators. The resulting plantlets were cultured under 93 mol m-2 s-1 illumination, 12 hour photoperiod regime and 25C 1 for 120 days with subculture to fresh identical media every 30 days. The addition of calcium at 9.38 mM to MS modified medium increased the production of fresh and dry mass of plantlets, whilst chlorine from calcium chloride dehydrate (CaCl2 2 H2O) in excess (3.35 mM) decreased both the fresh and dry mass of plantlets.

Dormancy as exaptation to protect mimetic seeds against deterioration before dispersal

Mimetic seeds simulate the appearance of fleshy fruits and arilled seeds without producing nutritive tissues as a reward for seed dispersers. In this strategy of seed dispersal, seeds may remain attached to the mother plant for long periods after maturity, increasing their availability to naive seed dispersers. The hypothesis that seed coat impermeability in many tropical Fabaceae with mimetic seeds serves as an exaptation to protect the seeds from deterioration and rotting while awaiting dispersal was investigated. Seed coat impermeability was evaluated in five mimetic-seeded species of tropical Fabaceae in south-eastern Brazil (Abarema langsdorffii, Abrus precatorius, Adenanthera pavonina, Erythrina velutina and Ormosia arborea) and in Erythrina speciosa, a `basal` species in its genus, which has monochromatic brown seeds and no mimetic displays. Seed hardness was evaluated as a defence against accelerated ageing (humid chamber at 41 degrees C for 144 h). Seed development and physiological potential of O. arborea was evaluated and the effect of holding mature seeds in pods on the mother plant in the field for a period of 1 year under humid tropical conditions was compared with seeds stored under controlled conditions (15 degrees C and 40 % relative air humidity). All five mimetic-seeded species, and E. speciosa, showed strong coat impermeability, which protected the seeds against deterioration in accelerated ageing. Most O. arborea seeds only became dormant 2 months after pod dehiscence. Germination of seeds after 1 year on the plant in a humid tropical climate was 56 %, compared with 80 % for seeds stored in controlled conditions (15 degrees C, 45 % relative humidity). Seedling shoot length after 1 year did not differ between seed sources. Dormancy acts in mimetic-seeded species as an exaptation to reduce seed deterioration, allowing an increase in their effective dispersal period and mitigating the losses incurred by low removal rates by naive avian frugivores.

IBA application for rooting of Eucalyptus benthamii Maiden and Cambage x Eucalyptus dunnii Maiden minicuttings

IBA application for rooting of Eucalyptus benthamii Maiden and Cambage x Eucalyptus dunnii Maiden minicuttings. Eucalyptus has great importance in the forestry sector and many advances in the area of improvement have been achieved with the advent of biotechnological techniques. However, some promising genotypes still do not have multiplication protocols with cloning techniques, such as minicutting. The study aimed to evaluate IBA concentrations for survival, rooting and vegetative vigor of E. benthamii x E. dunnii minicuttings, and determine the maximum technical efficiency dose. Ministumps H12, H19 and H20 clones were cultivated in a clonal minigarden under a semi-hydroponic system. For rooting, the rninicutting basal portion was plunged in hydro-alcoholic solutions, whose concentrations were: 0; 2,000; 4,000; 6,000 and 8,000 mg L(-1) of IBA. The experiment was conducted in a completely randomized design, with the factors consisting of three clones and five IBA concentrations, with five replications, containing 10 minicuttings per replication. IBA positively influenced the minicutting rooting processes, with differentiated behavior between the clones, with 30.32 to 55.45% rooting variation. The positives increments occurred until the highest IBA concentration for H12 and H19 clones. However, the range between 4,000 and 6,000 mg L(-1) of IBA treatments promoted the best rooting results for the H20 clone.

SacRALF1, a peptide signal from the grass sugarcane (Saccharum spp.), is potentially involved in the regulation of tissue expansion

Rapid alkalinization factor (RALF) is part of a growing family of small peptides with hormone characteristics in plants. Initially isolated from leaves of tobacco plants, RALF peptides can be found throughout the plant kingdom and they are expressed ubiquitously in plants. We took advantage of the small gene family size of RALF genes in sugarcane and the ordered cellular growth of the grass sugarcane leaves to gain information about the function of RALF peptides in plants. Here we report the isolation of two RALF peptides from leaves of sugarcane plants using the alkalinization assay. SacRALF1 was the most abundant and, when added to culture media, inhibited growth of microcalli derived from cell suspension cultures at concentrations as low as 0.1 mu M. Microcalli exposed to exogenous SacRALF1 for 5 days showed a reduced number of elongated cells. Only four copies of SacRALF genes were found in sugarcane plants. All four SacRALF genes are highly expressed in young and expanding leaves and show a low or undetectable level of expression in expanded leaves. In half-emerged leaf blades, SacRALF transcripts were found at high levels at the basal portion of the leaf and at low levels at the apical portion. Gene expression analyzes localize SacRALF genes in elongation zones of roots and leaves. Mature leaves, which are devoid of expanding cells, do not show considerable expression of SacRALF genes. Our findings are consistent with SacRALF genes playing a role in plant development potentially regulating tissue expansion.

Natural regeneration of Atlantic Forest species in the understory of Eucalyptus saligna Smith. in a former forest production unit at the Parque das Neblinas, Bertioga, SP

This study aimed at characterizing the potential for natural regeneration of native vegetation in the under-story of an earlier Eucalyptus saligna Smith production stand. The study was carried out at the Parque das Neblinas, Bertioga municipality, SP, in a 45 ha third rotation stand; which had been abandoned 15 years ago for natural regeneration to occur. The sampling was done in 24 plots of 20 x 40 m. The sampled area was of 19,200 m(2), with inventory made of 100% of the eucalyptus trees. All regeneration trees with a height >= 1.30 m and DBH >= 5.0 cm were measured, as well as adult individuals with DBH >= 5.0 cm; surveyed in two size classes. 1,417 individuals of E. saligna were measured, with a density of 738,02 individuals/ha and a basal area of 22.69 m(2)/ha. Among 2,763 natural regeneration individuals, 111 species belonged to 66 genera and 34 botanical families. The species represented 43.7% of the tree richness of neighboring native forest fragments. The total estimated density and the basal area were respectively 1,052.6 individuals/ha and 6.4 m(2)/ha of autochthonous trees with DBH >= 5.0 cm (Class 1); while for regeneration there were 3,864.58 individuals/ha, and 2.76 m(2)/ha of individuals with a height >= 1.30 m and DBH <5.0 cm (Class 2). Shannon diversity (H`) was 2.83 and 3.68, respectively, for Classes 1 and 2, and the corrected species richness for a 1000-individual sample (R(1000)) were 75.6 and 87.29 (Fisher`s a index) for the same classes. The majority of the species (34.84%) was typical from the understory of wet tropical forest and had zoochoric fruit dispersal (67.57%). The results indicate that, under these conditions, a eucalyptus forest is able to provide adequate regeneration niches for native vegetation, and may represent a sink habitat for local populations.

The development and production of leaves and tillers by Marandu palisadegrass fertilised with nitrogen and sulphur

The effects of combined nitrogen and sulphur fertilisation on the dynamics of leaf and tiller appearance in Marandu palisadegrass (Brachiaria brizantha cv. Marandu) and its impact on dry matter production were evaluated in a greenhouse study. Grass seedlings were grown in pots filled with a soil classified as an Entisol and were harvested after 43 days, a further 35 days and finally after 48 more days. Five rates of N (0, 100, 200, 300 and 400 mg/dm(3)) and 5 rates of S (0, 10, 20, 30 and 40 mg/dm(3)) were tested in an incomplete factorial design with 4 replications. Leaf and tiller development were monitored every 3 days by counting the appearance of recently expanded leaves and new basal tillers. The phyllochron and thermal time between appearance of tillers decreased as N and S fertiliser levels increased to about 300 and 25 mg/dm(3), respectively, then tended to increase. In contrast, leaf and tiller appearance rates increased with the supply of these nutrients to similar levels, then tended to decline. Leaf and tiller production and dry matter yields were affected by both N and S levels, with the role of S increasing as the growth phases increased.

The expression of efflux and uptake transporters are regulated by statins in Caco-2 and HepG2 cells

Aim: Statin disposition and response are greatly determined by the activities of drug metabolizing enzymes and efflux/uptake transporters. there is little information on the regulation of these proteins in human cells after statin therapy. In this study, the effects of atorvastatin and simvastatin on mRNA expression of efflux (ABCB1, ABCG2 and ABCC2) and uptake (SLCO1B1, SLCO2B1 and SLC22A1) drug transporters in Caco-2 and HepG2 cells were investigated. Methods: Quantitative real-time PCR was used to measure mRNA levels after exposure of HepG2 and Caco-2 cells to statins. Results: Differences in mRnA basal levels of the transporters were as follows: ABCC2>ABCG2>ABCB1>SLCO1B1>>>SLC22A1>SLC O2B1 for HepG2 cells, and SLCO2B1>>ABCC2>ABCB1>ABCG2>>>SLC22A1 for Caco-2 cells. While for HepG2 cells, ABCC2, ABCG2 and SLCO2B1 mRnA levels were significantly up-regulated at 1, 10 and 20 mu mol/L after 12 or 24 h treatment, in Caco-2 cells, only the efflux transporter ABCB1 was significantly down-regulated by two-fold following a 12 h treatment with atorvastatin. Interestingly, whereas treatment with simvastatin had no effect on mRNA levels of the transporters in HepG2 cells, in Caco-2 cells the statin significantly down-regulated ABCB1, ABCC2, SLC22A1, and SLCO2B1 mRnA levels after 12 or 24 h treatment. Conclusion: These findings reveal that statins exhibits differential effects on mRNA expression of drug transporters, and this effect depends on the cell type. Furthermore, alterations in the expression levels of drug transporters in the liver and/or intestine may contribute to the variability in oral disposition of statins.

ABCB1 and ABCC1 expression in peripheral mononuclear cells is influenced by gene polymorphisms and atorvastatin treatment

This study investigated the effects of atorvastatin on ABCB1 and ABCC1 mRNA expression on peripheral blood mononuclear cells (PBMC) and their relationship with gene polymorphisms and lowering-cholesterol response. one hundred and thirty-six individuals with hypercholesterolemia were selected and treated with atorvastatin (10 mg/day/4 weeks). Blood samples were collected for serum lipids and apolipoproteins measurements and DNA and RNA extraction. ABCB1 (C3435T and G2677T/A) and ABCC1 (G2012T) gene polymorphisms were identified by polymerase chain reaction-restriction (PCR)-RFLP and mRNA expression was measured in peripheral blood mononuclear cells by singleplex real-time PCR. ABCB1 polymorphisms were associated with risk for coronary artery disease (CAD) (p < 0.05). After atorvastatin treatment, both ABCB1 and ABCC1 genes showed 50% reduction of the mRNA expression (p < 0.05). Reduction of ABCB1 expression was associated with ABCB1 G2677T/A polymorphism (p = 0.039). Basal ABCB1 mRNA in the lower quartile (<0.024) was associated with lower reduction rate of serum low-density lipoprotein (LDL) cholesterol (33.4 +/- 12.4%) and apolipoprotein B (apoB) (17.0 +/- 31.3%) when compared with the higher quartile (>0.085: LDL-c = 40.3 +/- 14.3%; apoB = 32.5 +/- 10.7%; p < 0.05). ABCB1 substrates or inhibitors did not affect the baseline expression, while ABCB1 inhibitors reversed the effects of atorvastatin on both ABCB1 and ABCC1 transporters. In conclusion, ABCB1 and ABCC1 mRNA levels in PBMC are modulated by atorvastatin and ABCB1 G2677T/A polymorphism. and ABCB1 baseline expression is related to differences in serum LDL cholesterol and apoB in response to atorvastatin. (C) 2008 Elsevier Inc. All rights reserved.

Prostacyclin, not only nitric oxide, is a mediator of the vasorelaxation induced by acetylcholine in aortas from rats submitted to cecal ligation and perforation (CLP)

Nitric oxide has been pointed out as the main agent involved in the vasodilatation, which is the major symptom of septic shock. However, there must be another mediator contributing to the circulatory failure observed in sepsis. This study aimed to investigate the endothelium-dependent relaxation induced by acetylcholine and the factors involved in this relaxation, using aortic rings isolated from rats submitted to cecal ligation and perforation (CLP), 2 h after induction of sepsis, which characterizes the hyperdynamic phase of sepsis. Under inhibition of constitutive NO-synthases (cNOS), the relaxation induced by acetylcholine was greater in the aortic rings of rats submitted to CLP compared with sham-operated rat aortic rings. The cyclooxygenase inhibitor indomethacin normalized this response, and the concentration of the stable metabolite of prostacyclin in the aorta of CLP rats increased in basal conditions and after stimulation with acetylcholine. Acetylcholine-induced NO production was lower in the endothelial cells from the aorta of CLP rats compared with sham rat aorta, but the protein expression of the cNOS was not altered. Moreover, iNOS protein expression could not be detected. Therefore, prostacyclin, and not only nitric oxide, is a mediator of the vasorelaxation induced by acetylcholine in aortas from rats submitted to CLP. (C) 2011 Elsevier Inc. All rights reserved.