Estresse salino em plantas jovens de cana-deaçúcar: respostas bioquímicas e fisiológicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos da alta temperatura na pigmentação visceral e no epitélio germinativo masculino em Physalaemus nattereri e Leptodactylus fuscus (Anura)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo de genes de Candida albicans com função desconhecida quanto à formação de biofilme, características biológicas e interação patógeno- hospedeiro

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of primovaccination and booster vaccination on serum cortisol and humoral immune response in cattle

The objective of this study was to evaluate the effect of one or two doses of the anti-rabies vaccination on the serum concentration of cortisol and the humoral immune response in cattle as well as the correlation between serum cortisol concentrations and the titers of rabies-neutralizing antibodies. Nelore cattle were randomly assigned to one of three groups, which were vaccinated with one dose of rabies vaccine (group GVSR, N = 15), two doses of rabies vaccine (group GVR, N = 15) or were not vaccinated (group Gc, N = 15). A commercial liquid inactivated rabies vaccine was used. The stressors imposed on the cattle were vaccination, corral handling and the presence of people. Blood samples were collected on days 0, 30 and 60 post-vaccination. Serum cortisol concentrations were determined using a solid-phase radioimmunoassay, and rabies antibody titers were determined using a serum neutralization test with BHK21 cells (RFFIT). Both serum cortisol concentrations and antibody titers increased after the second (booster) vaccination (P < 0.05). In all the groups, the serum cortisol concentrations increased after the cattle were handled in the corral (P < 0.05). No correlation was observed between the serum cortisol concentrations and the antibody titers with any treatment or on any observation day. In conclusion, booster vaccination is indispensable for primovaccinated cattle in achieving high and protective levels of rabies antibodies. Although booster vaccination and frequent cattle handling in corrals are stressors, the response is not strong enough to cause immunosuppression in cattle.

Immunomodulation with β-glucan in matrinxã (Brycon amazonicus)

Pós-graduação em Zootecnia - FCAV

Caminhamento fotogramétrico com arranjo triangular de câmaras fotográficas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Learned helplessness in the rat: Effect of response topography in a within-subject design

Three experiments investigated learned helplessness in rats manipulating response topography within-subject and different intervals between treatment and tests among groups. In Experiment 1, rats previously exposed to inescapable shocks were tested under an escape contingency where either jumping or nose poking was required to terminate shocks: tests were run either 1, 14 or 28 days after treatment. Most rats failed to jump, as expected, but learned to nose poke, regardless of the interval between treatment and tests and order of testing. The same results were observed in male and female rats from a different laboratory (Experiment 2) and despite increased exposure to the escape contingencies using a within-subject design (Experiment 3). Furthermore, no evidence of helplessness reversal was observed, since animals failed to jump even after having learned to nose-poke in a previous test session. These results are not consistent with a learned helplessness hypothesis, which claims that shock (un)controllability is the key variable responsible for the effect. They are nonetheless consistent with the view that inescapable shocks enhance control by irrelevant features of the relationship between the environment and behavior. (C) 2010 Elsevier B.V. All rights reserved.

Stabilization for an ensemble of half-spin systems

Feedback stabilization of an ensemble of non interacting half spins described by the Bloch equations is considered. This system may be seen as an interesting example for infinite dimensional systems with continuous spectra. We propose an explicit feedback law that stabilizes asymptotically the system around a uniform state of spin +1/2 or -1/2. The proof of the convergence is done locally around the equilibrium in the H-1 topology. This local convergence is shown to be a weak asymptotic convergence for the H-1 topology and thus a strong convergence for the C topology. The proof relies on an adaptation of the LaSalle invariance principle to infinite dimensional systems. Numerical simulations illustrate the efficiency of these feedback laws, even for initial conditions far from the equilibrium. (C) 2011 Elsevier Ltd. All rights reserved.

Plasma corticosterone levels in mouse models of pain

Background: Pain markedly activates the hypothalamic-pituitary-adrenal (HPA) axis and increases plasma corticosterone release interfering significantly with nociceptive behaviour as well as the mechanism of action of analgesic drugs. Aims/Methods: In the present study, we monitored the time course of circulating corticosterone in two mouse strains (C57Bl/6 and Balb/C) under different pain models. In addition, the stress response was investigated following animal handling, intrathecal (i.t.) manipulation and habituation to environmental conditions commonly used in nociceptive experimental assays. We also examined the influence of within-cage order of testing on plasma corticosterone. Results: Subcutaneous injection of capsaicin precipitated a prompt stress response whereas carrageenan and complete Freund's adjuvant induced an increased corticosterone release around the third hour post-injection. However, carrageenan induced a longer increased corticosterone in C57Bl/6 mice. In partial sciatic nerve ligation, neuropathic pain model corticosterone increased only in the first days whereas mechanical hypersensitivity remained much longer. Animal handling also represents an important stressor whereas the i.t. injection per se does not exacerbate the handling-induced stress response. Moreover, the order of testing animals from the same cage does not interfere with plasma corticosterone levels in the intrathecal procedure. Animal habituation to the testing apparatus also does not reduce the immediate corticosterone increase as compared with non-habituated mice. Conclusion: Our data indicate that HPA axis activation in acute and chronic pain models is time dependent and may be dissociated from evoked hyperalgesia. Therefore, HPA-axis activation represents an important variable to be considered when designing experimental assays of persistent pain as well as for interpretation of data.

Associação entre sistema de incentivos gerenciais e práticas de contabilidade gerencial

O princípio da controlabilidade prevê que os gestores deveriam ser avaliados com base em fatores controláveis. Consequentemente, os incentivos gerenciais estariam relacionados a práticas de contabilidade gerencial capazes de evitar que os gestores sejam responsabilizados por resultados financeiros além do controle gerencial, tais como análise por centro de responsabilidade, custo padrão, preço de transferência, orçamento e avaliação de desempenho. Este artigo desenvolve um estudo de campo para investigar se há relação entre a presença de incentivos gerenciais e as práticas de contabilidade gerencial associadas ao princípio da controlabilidade. Entrevistas in loco foram realizadas para a coleta de dados em nível organizacional e testes estatísticos não paramétricos foram utilizados para a análise dos dados. Entre as práticas de contabilidade gerencial examinadas, os resultados sugerem que apenas orçamento anual, análise por centro de responsabilidade e avaliação de desempenho estão associados à presença de sistemas de incentivos nas empresas entrevistadas.

Abundance of biofilm on intertidal rocky shores: Can trampling by humans be a negative influence?

Trampling by human visitors to rocky shores is a known stressor on macroorganisms. However, the effects of trampling on rocky intertidal biofilm, a complex association of microorganisms of ecological importance in coastal communities, have not been quantified. We evaluated the impact of trampling frequency and intensity on total biomass of epilithic microalgae on intertidal rocky shores in the southeast of Brazil. There was a trend of increase in the variability of biomass of biofilm in function of intensity of trampling, but no significant effects emerged among trampling treatments. The low influence of trampling on biofilm might be a result of the small dimensions of the organisms coupled with their natural resilience and roughness of the substrate; the former preventing the removal of biofilm layers by shoes and facilitating their quick recovery. Our results provide insights for management and conservation of coastal ecosystems revealing a weaker impact of trampling on biofilm than that reported on macroorganisms. (C) 2012 Elsevier Ltd. All rights reserved.

Associação entre sistema de incentivos gerenciais e práticas de contabilidade gerencial

O princípio da controlabilidade prevê que os gestores deveriam ser avaliados com base em fatores controláveis. Consequentemente, os incentivos gerenciais estariam relacionados a práticas de contabilidade gerencial capazes de evitar que os gestores sejam responsabilizados por resultados financeiros além do controle gerencial, tais como análise por centro de responsabilidade, custo padrão, preço de transferência, orçamento e avaliação de desempenho. Este artigo desenvolve um estudo de campo para investigar se há relação entre a presença de incentivos gerenciais e as práticas de contabilidade gerencial associadas ao princípio da controlabilidade. Entrevistas in loco foram realizadas para a coleta de dados em nível organizacional e testes estatísticos não paramétricos foram utilizados para a análise dos dados. Entre as práticas de contabilidade gerencial examinadas, os resultados sugerem que apenas orçamento anual, análise por centro de responsabilidade e avaliação de desempenho estão associados à presença de sistemas de incentivos nas empresas entrevistadas.

Fluoxetine exposure during pregnancy and lactation: effects on acute stress response and behavior in the novelty-suppressed feeding are age and gender-dependent in rats

Fluoxetine (FLX) is commonly used to treat anxiety and depressive disorders in pregnant women. Since FLX crosses the placenta and is excreted in milk, maternal treatment with this antidepressant may expose the fetus and neonate to increased levels of serotonin (5-HT). Long-term behavioral abnormalities have been reported in rodents exposed to higher levels of 5-HT during neurodevelopment. In this study we evaluated if maternal exposure to FLX during pregnancy and lactation would result in behavioral and/or stress response disruption in adolescent and adult rats. Our results indicate that exposure to FLX influenced restraint stress-induced Fos expression in the amygdala in a gender and age-specific manner. In male animals, a decreased expression was observed in the basolateral amygdala at adolescence and adulthood; whereas at adulthood, a decrease was also observed in the medial amygdala. A lack of FLX exposure effect was observed in females and also in the paraventricular nucleus of both genders. Regarding the behavioral evaluation, FLX exposure did not induce anhedonia in the sucrose preference test but decreased the latency to feed of both male and female adolescent rats evaluated in the novelty-suppressed feeding test. In conclusion, FLX exposure during pregnancy and lactation decreases acute amygdalar stress response to a psychological stressor in males (adolescents and adults) as well as influences the behavior of adolescents (males and females) in a model that evaluates anxiety and/or depressive-like behavior. Even though FLX seems to be a developmental neurotoxicant, the translation of these findings to human safe assessment remains to be determined since it is recognized that not treating a pregnant or lactating woman may also impact negatively the development of the descendants.

Chronic unpredictable mild stress alters an anxiety-related defensive response, Fos immunoreactivity and hippocampal adult neurogenesis

Previous results show that elevated T-maze (ETM) avoidance responses are facilitated by acute restraint. Escape, on the other hand, was unaltered. To examine if the magnitude of the stressor is an important factor influencing these results, we investigated the effects of unpredictable chronic mild stress (UCMS) on ETM avoidance and escape measurements. Analysis of Fos protein immunoreactivity (Fos-ir) was used to map areas activated by stress exposure in response to ETM avoidance and escape performance. Additionally, the effects of the UCMS protocol on the number of cells expressing the marker of migrating neuroblasts doublecortin (DCX) in the hippocampus were investigated. Corticosterone serum levels were also measured. Results showed that UCMS facilitates ETM avoidance, not altering escape. In unstressed animals, avoidance performance increases Fos-ir in the cingulate cortex, hippocampus (dentate gyrus) and basomedial amygdala, and escape increases Fos-ir in the dorsolateral periaqueductal gray and locus ceruleus. In stressed animals submitted to ETM avoidance, increases in Fos-ir were observed in the cingulate cortex, ventrolateral septum, hippocampus, hypothalamus, amygdala, dorsal and median raphe nuclei. In stressed animals submitted to ETM escape, increases in Fos-ir were observed in the cingulate cortex, periaqueductal gray and locus ceruleus. Also, UCMS exposure decreased the number of DCX-positive cells in the dorsal and ventral hippocampus and increased corticosterone serum levels. These data suggest that the anxiogenic effects of UCMS are related to the activation of specific neurobiological circuits that modulate anxiety and confirm that this stress protocol activates the hypothalamus-pituitary-adrenal axis and decreases hippocampal adult neurogenesis.

Maternal immune activation increases the corticosterone response to acute stress without affecting the hypothalamic monoamine content and sleep patterns in male mice offspring

Background/Aims: Early life experiences are homeostatic determinants for adult organisms. We evaluated the impact of prenatal immune activation during late gestation on the neuroimmune-endocrine function of adult offspring and its interaction with acute stress. Methods: Pregnant Swiss mice received saline or lipopolysaccharide (LPS) on gestational day 17. Adult male offspring were assigned to the control or restraint stress condition. We analyzed plasmatic corticosterone and catecholamine levels, the monoamine content in the hypothalamus, striatum and frontal cortex, and the sleep-wake cycle before and after acute restraint stress. Results and Conclusion: Offspring from LPS-treated dams had increased baseline norepinephrine levels and potentiated corticosterone secretion after the acute stressor, and no effect was observed on hypothalamic monoamine content or sleep behavior. The offspring of immune-activated dams exhibited impairments in stress-induced serotonergic and dopaminergic alterations in the striatum and frontal cortex. The data demonstrate a distinction between the plasmatic levels of corticosterone in response to acute stress and the hypothalamic monoamine content and sleep patterns. We provide new evidence regarding the influence of immune activation during late gestation on the neuroendocrine homeostasis of offspring.