Baseline and stress-induced plasma corticosterone concentrations of mice selectively bred for high voluntary wheel running

The hypothalamic-pituitary-adrenal (HPA) axis is important in regulating energy metabolism and in mediating responses to stressors, including increasing energy availability during physical exercise. In addition, glucocorticoids act directly on the central nervous system and influence behavior, including locomotor activity. To explore potential changes in the HPA axis as animals evolve higher voluntary activity levels, we characterized plasma corticosterone (CORT) concentrations and adrenal mass in four replicate lines of house mice that had been selectively bred for high voluntary wheel running (HR lines) for 34 generations and in four nonselected control (C) lines. We determined CORT concentrations under baseline conditions and immediately after exposure to a novel stressor (40 min of physical restraint) in mice that were housed without access to wheels. Resting daytime CORT concentrations were approximately twice as high in HR as in C mice for both sexes. Physical restraint increased CORT to similar concentrations in HR and C mice; consequently, the proportional response to restraint was smaller in HR than in C animals. Adrenal mass did not significantly differ between HR and C mice. Females had significantly higher baseline and postrestraint CORT concentrations and significantly larger adrenal glands than males in both HR and C lines. Replicate lines showed significant variation in body mass, length, baseline CORT concentrations, and postrestraint CORT concentrations in one or both sexes. Among lines, both body mass and length were significantly negatively correlated with baseline CORT concentrations, suggesting that CORT suppresses growth. Our results suggest that selection for increased locomotor activity has caused correlated changes in the HPA axis, resulting in higher baseline CORT concentrations and, possibly, reduced stress responsiveness and a lower growth rate. © 2007 by The University of Chicago. All rights reserved.

Influência de solos de diferentes texturas no desenvolvimento de plantas de Eucalyptus urograndis submetidas a déficit hídrico

The studies were developed with plants of Eucalyptus urograndis under greenhouse conditions, at Paulista State University (UNESP), Botucatu - SP, from March to July, 2005. The objective was to evaluate hydric stress influence on morphological and physiological characteristics of plants in clayay (1) and medium (2) soil texture. Two water treatment were used: -0.03 and -1.5 MPa minimum soil water potentials (□w). Plants from soil 2 and - 1.5MPa showed 43% reduction on leaf área, 34% on base stem diameter, 54% on aerial vegetal dry matter and plants from soil 1 presented 42.3% reduction on leaf área, 39,5% base stem diameter and 42% dry matter root reduction in relation to -0.03 MPa. The lowest leaf water potential (□f) value was-17.166 MPa on □w = -1.5 MPa and soil 2 and the greatest one on soil 1 and □w = -0.03 MPa., -6.766 MPa. The treatment -0.03MPa showed about 11,3% higher transpiration values than those plants from -1.5MPa. The higher Rs value (2.149 s.cm-1) occurred on plants under -1.5MPa and soil 2. There was significant correlation between Tf and Rs, and the treatmens from medium soil were more sensitive, reaching until 32°C.

Soluções nutritivas no desenvolvimento do crisântemo cultivado em vaso

Although the information about nutritive solution for potted chrysanthemum is still incongruent, the objective of this work was to evaluate the effect of nutritive solutions in the development of Miramar chrysanthemum cultivated in pots at FCAV-UNESP, Jaboticabal-SP. The experiment had a randomized block design with split-plot evaluation and treatments corresponding to four nutritive solutions consisting of commercial fertilizers (S1, S2, S3, S4) evaluated at 0, 14, 28, 42, 56 and 70 days after rooting (DAE), with five replications. The plant height, leaf area, number of leaves, stem diameter, total dry matter mass of aerial part and roots; number and diameter of inflorescences, and physiological indexes of growth analysis were evaluated. The nutritive solutions did not interfere significantly in stem diameter, number and diameter of inflorescences and dry matter of roots, although S3 and S4 provided the highest plants, leaf area, number of leaves, total dry matter of aerial part. The physiological indexes showed that plants presented an accelerated growth from 14 to 28 DAE with S4 and S3 solutions and therefore they were considered the best solutions.

Homologies of floral structures in velloziaceae with particular reference to the corona

New data on floral morphology, development, and vasculature in two Brazilian genera of the monocot family Velloziaceae (Pandanales) are used to explore the homologies of their unusual floral structures, especially the corona of Barbacenia and the corona-like appendages and multiple stamens of some Vellozia species. All Velloziaceae have epigynous flowers. Some species of Vellozia are polyandrous, and stamen number can be variable within species. In Vellozia jolyi, there is a single stamen opposite each sepal and a stamen fascicle (of three secondary stamens) opposite each petal. Each stamen possesses a single vascular bundle, and these are united into a single aggregate bundle in proximal regions of the fascicle. Stamens mature centripetally within each fascicle. The coronal appendages of both genera are closely associated with the stamens, but they share some vasculature with the tepals and develop late in ontogeny. The coronal organs cannot readily be homologized with any of the typical floral organs, but they show partial homology with both tepals and stamens. They are most readily interpreted as a late elaboration of the region between the petals and stamens associated with epigyny and the hypanthium. © 2010 by The University of Chicago. All rights reserved.

Biochemical biomarkers in Nile tilapia (Oreochromis niloticus) after short-term exposure to diesel oil, pure biodiesel and biodiesel blends

Fossil fuels such as diesel are being gradually replaced by biodiesel, a renewable energy source, cheaper and less polluting. However, little is known about the toxic effects of this new energy source on aquatic organisms. Thus, we evaluated biochemical biomarkers related to oxidative stress in Nile tilapia (Oreochromis niloticus) after two and seven exposure days to diesel and pure biodiesel (B100) and blends B5 and B20 at concentrations of 0.01 and 0.1mLL -1. The hepatic ethoxyresorufin-O-deethylase activity was highly induced in all groups, except for those animals exposed to B100. There was an increase in lipid peroxidation in liver and gills in the group exposed to the higher concentration of B5. All treatments caused a significant increase in the levels of 1-hydroxypyrene excreted in the bile after 2 and 7d, except for those fish exposed to B100. The hepatic glutathione-S-transferase increased after 7d in animals exposed to the higher concentration of diesel and in the gill of fish exposed to the higher concentration of pure diesel and B5, but decreased for the two tested concentrations of B100. Superoxide dismutase, catalase and glutathione peroxidase also presented significant changes according to the treatments for all groups, including B100. Biodiesel B20 in the conditions tested had fewer adverse effects than diesel and B5 for the Nile tilapia, and can be suggested as a less harmful fuel in substitution to diesel. However, even B100 could activate biochemical responses in fish, at the experimental conditions tested, indicating that this fuel can also represent a risk to the aquatic biota. © 2011 Elsevier Ltd.

Distribution related to temperature and salinity of the shrimps Acetes americanus and Peisos petrunkevitchi (Crustacea: Sergestoidea) in the south-eastern Brazilian littoral zone

The abundance and ecological distribution of Acetes americanus and Peisos petrunkevitchi were investigated from July 2006 to June 2007, in Ubatuba, Brazil. Eight transects were identified and sampled monthly: six of these transects were located in Ubatuba bay, with depths reaching 21 m, and the other two transects were in estuarine environments. A total of 33,888 A. americanus shrimp were captured, with the majority coming from the shallower transects (up to 10 m). Conversely, 6,173 of the P. petrunkevitchi shrimps were captured in deeper areas (from 9 to 21 m). No individuals from either species were found in the estuary. The highest abundances obtained for both species were sampled during the summer. Canonical correlation analysis resulted in a coefficient value of 0.68 (P = 0.00). The abundance of both species was strongly correlated with depth. Variations in temperature and salinity values were also informative in predicting the seasonal presence of P. petrunkevitchi in deeper areas and A. americanus in the shallower areas of the bay. It is conceivable that the shrimp adjust their ecological distribution according to their intrinsic physiological limitations. © 2012 Marine Biological Association of the United Kingdom.

Visceral colouration of Eupemphix nattereri (Anura: Leiuperidae): effects of NDP-α-melanocyte stimulating hormone

Amphibians have melanin-containing cells in visceral organs that are similar to pigmentary cells from the epidermis. Both of them are derived from the ectodermal neural crest. Epidermal cells respond to α-melanocyte stimulating hormone (α-MSH), which is associated to the dispersion of melanin granules within melanocytes. Therefore, our aim was to test whether a non-degradable analogue of the α-MSH changes the superficial colouration of organs of Eupemphix nattereri. The hormone rapidly increases (within 12 hours) the colouration on the surface of the pericardium, heart, testes, nerves of the lumbar plexus, and lumbosacral parietal peritoneum. Colouration increased late (after 24 hours) in the kidneys and mesentery following hormone administration. However, this hormone did not change colouration of intestine, rectum and lungs. Our findings could be explained by the similarities between epidermal and visceral melanocytes, since both cells have a common embryonic origin. Furthermore, the increase in visceral colouration may be related to the dispersion of melanosomes within melanocytes, which causes the darkening of organs. Our results demonstrate for the first time that the visceral colouration is responsive, thereby altering the internal pattern of organs' colouration in anurans. © 2013 Copyright 2013 Unione Zoologica Italiana.

Biochemical responses in armored catfish (Pterygoplichthys anisitsi) after short-term exposure to diesel oil, pure biodiesel and biodiesel blends

Biodiesel fuel is gradually replacing petroleum-based diesel oil use. Despite the biodiesel being considered friendlier to the environment, little is known about its effects in aquatic organisms. In this work we evaluated whether biodiesel exposure can affect oxidative stress parameters and biotransformation enzymes in armored catfish (Pterygoplichthys anisitsi, Loricariidae), a South American endemic species. Thus, fish were exposed for 2 and 7d to 0.01mLL-1 and 0.1mLL-1 of pure diesel, pure biodiesel (B100) and blends of diesel with 5% (B5) and 20% (B20) biodiesel. Lipid peroxidation (malondialdehyde) levels and the activities of the enzymes glutathione S-transferase, superoxide dismutase, catalase and glutathione peroxidase were measured in liver and gills. Also, DNA damage (8-oxo-7, 8-dihydro-2'-deoxyguanosine) levels in gills and 7-ethoxyresorufin-O-deethylase activity in liver were assessed. Pure diesel, B5 and B20 blends changed most of the enzymes tested and in some cases, B5 and B20 induced a higher enzyme activity than pure diesel. Antioxidant system activation in P. anisitsi was effective to counteract reactive oxygen species effects, since DNA damage and lipid peroxidation levels were maintained at basal levels after all treatments. However, fish gills exposed to B20 and B100 presented increased lipid peroxidation. Despite biodiesel being more biodegradable fuel that emits less greenhouse gases, the increased lipid peroxidation showed that biofuel and its blends also represent hazards to aquatic biota. © 2013 Elsevier Ltd.

Fish exposure to nano-TiO2 under different experimental conditions: Methodological aspects for nanoecotoxicology investigations

The ecotoxicology of nano-TiO2 has been extensively studied in recent years; however, few toxicological investigations have considered the photocatalytic properties of the substance, which can increase its toxicity to aquatic biota. The aim of this work was to evaluate the effects on fish exposed to different nano-TiO2 concentrations and illumination conditions. The interaction of these variables was investigated by observing the survival of the organisms, together with biomarkers of biochemical and genetic alterations. Fish (Piaractus mesopotamicus) were exposed for 96h to 0, 1, 10, and 100mg/L of nano-TiO2, under visible light, and visible light with ultraviolet (UV) light (22.47J/cm2/h). The following biomarkers of oxidative stress were monitored in the liver: concentrations of lipid hydroperoxide and carbonylated protein, and specific activities of superoxide dismutase, catalase, and glutathione S-transferase. Other biomarkers of physiological function were also studied: the specific activities of acid phosphatase and Na,K-ATPase were analyzed in the liver and brain, respectively, and the concentration of metallothionein was measured in the gills. In addition, micronucleus and comet assays were performed with blood as genotoxic biomarkers. Nano-TiO2 caused no mortality under any of the conditions tested, but induced sublethal effects that were influenced by illumination condition. Under both illumination conditions tested, exposure to 100mg/L showed an inhibition of acid phosphatase activity. Under visible light, there was an increase in metallothionein level in fish exposed to 1mg/L of nano-TiO2. Under UV light, protein carbonylation was reduced in groups exposed to 1 and 10mg/L, while nucleus alterations in erythrocytes were higher in fish exposed to 10mg/L. As well as improving the understanding of nano-TiO2 toxicity, the findings demonstrated the importance of considering the experimental conditions in nanoecotoxicological tests. This work provides information for the development of protocols to study substances whose toxicity is affected by illumination conditions. © 2013 Elsevier B.V..

Estresse oxidativo em clones de seringueira sob ataque de antracnose-das-folhas

Pós-graduação em Ciência Florestal - FCA

Estresse de manejo criatório em rãs-touro: aspectos hormonais, hematológicos e morfológicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Resposta fisiológica, qualidade da carne e expressão gênica no músculo esquelético de frangos de corte sob estresse por calor que receberam antioxidantes na dieta

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Proteína e energia digestíveis e colina para Tilápia-do-Nilo: desempenho e respostas fisiológicas em condições de estresse

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos das catecolaminas sobre a reposição volêmica com solução fisiológica. Repercussão sobre a variabilidade da frequência cardíaca de coelhos submetidos à hemorragia: estudo por análise espectral

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aspectos fisiológicos de Chrysomya megacephala (F.) (Diptera: Calliphoridae): metabolismo energético, termorregulação e neurofisiologia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)