Adaptabilidade e estabilidade fenotípica de genótipos de cenoura

Avaliaram-se a adaptabilidade e a estabilidade fenotípica de dez genótipos de cenoura, nove de polinização aberta [Alvorada (FELTRIN); Tropical (ISLA); Brasília (ISLA); Nova Brasília (ISLA); Carandaí (SVS); Brasília (SVS); Brazlândia (HORTEC); HT-2000 (HORTEC), e Brasília-RL (SAKATA)] e o híbrido AF-845 (SAKATA), em semeaduras, de janeiro e março, em São José do Rio Pardo (SP), janeiro e fevereiro, em Ponta Grossa (PR), e na primeira e última semana de fevereiro, em São Gotardo (MG), e Carandaí (MG), totalizando oito experimentos (SJRP-JAN; SJRP-MAR; PG-JAN; PG-FEV; SG-FEV'; SG-FEV''; C-FEV', e C-FEV''), que foram implementados em blocos casualizados com quatro repetições. Os dados foram submetidos à análise de variância individual e conjunta, e à análise de adaptabilidade e de estabilidade. Dos oito ambientes testados, apenas C-FEV'', PG-JAN e SG-FEV'' foram considerados favoráveis ao cultivo de cenoura, com destaque para C-FEV''. Entre genótipos, na maioria dos ambientes, 'Brazlândia' se destacou tanto na produtividade total, quanto na produtividade comercial de raízes. Na análise de adaptabilidade, 'Brazlândia' e 'Brasília-RL' indicaram possuir desempenho mais do que proporcional à melhoria promovida pelo ambiente, sendo indicados para semeaduras em ambientes favoráveis. O híbrido AF-845 mostrou ter pequena capacidade em responder às variações ambientais, não sendo indicado para nenhum dos ambientes estudados. Os genótipos de cenoura, em geral, apresentaram estabilidade de comportamento nos ambientes estudados.

Adaptabilidade e estabilidade fenotípica de cultivares de cenoura

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

Serotonergic neurons in the median raphe nucleus regulate inhibitory avoidance but not escape behavior in the rat elevated T-maze test of anxiety

Rationale: A wealth of evidence supports the involvement of the serotonergic neurons of the median raphe nucleus (MRN) in anxiety. However, it is presently unclear whether serotonergic pathways arising from this nucleus play distinguishing regulatory roles in defensive behaviors that have been associated with specific subtypes of anxiety disorders. Objectives: To evaluate the role of the MRN serotonergic neurons in the regulation of two defensive behaviors, inhibitory avoidance and escape, which have been related, respectively, to generalized anxiety and panic disorders. Methods: Male Wistar rats were submitted to the elevated T-maze test of anxiety after intra-MRN administration of drugs that either non-selectively or selectively change the activity of the serotonergic neurons. Results: Intra-MRN injection of FG 7142 (0.04 and 0.08 nmol) and kainic acid (0.03 and 0.06 nmol), drugs that non-selectively stimulate the MRN serotonergic neurons, facilitated inhibitory avoidance acquisition, but impaired escape performance. Microinjection of muscimol (0.11 and 0.22 nmol), a compound that non-selectively inhibits the activity of the MRN serotonergic neurons, impaired inhibitory avoidance and facilitated escape performance. Both kainic acid and muscimol also changed rat locomotion in the open-field test. Intra-MRN injection of 8-OH-DPAT (0.6-15 nmol) and WAY-100635 (0.18-0.74 nmol), respectively an agonist and an antagonist of somatodendritic 5-HT1A receptors located on serotonergic neurons of the MRN, only affected inhibitory avoidance-while the former inhibited the acquisition of this behavior, the latter facilitated it. Conclusion: MRN serotonergic neurons seem to be selectively involved in the regulation of inhibitory avoidance in the elevated T-maze. This result supports the proposal that 5-HT pathways departing from this nucleus play an important role in anxiety processing, with implications for pathologies such as generalized anxiety disorder.

The dorsal raphe nucleus exerts opposed control on generalized anxiety and panic-related defensive responses in rats

It has been proposed that the ascending dorsal raphe (DR)-serotonergic (5-HT) pathway facilitates conditioned avoidance responses to potential or distal threat, while the DR-periventricular 5-HT pathway inhibits unconditioned flight reactions to proximal danger. Dysfunction on these pathways would be, respectively, related to generalized anxiety (GAD) and panic disorder (PD). To investigate this hypothesis, we microinjected into the rat DR the benzodiazepine inverse receptor agonist FG 7142, the 5-HT1A receptor agonist 8-OH-DPAT or the GABA(A) receptor agonist muscimol. Animals were evaluated in the elevated T-maze (ETM) and light/dark transition test. These models generate defensive responses that have been related to GAD and PD. Experiments were also conducted in the ETM 14 days after the selective lesion of DR serotonergic neurons by 5,7-dihydroxytriptamine (DHT). In all cases, rats were pre-exposed to one of the open arms of the ETM 1 day before testing. The results showed that FG 7142 facilitated inhibitory avoidance, an anxiogenic effect, while impairing one-way escape, an anxiolytic effect. 8-OH-DPAT, muscimol, and 5,7-DHT-induced lesions acted in the opposite direction, impairing inhibitory avoidance while facilitating one-way escape from the open arm. In the light/dark transition, 8-OH-DPAT and muscimol increased the time spent in the lighted compartment, an anxiolytic effect. The data supports the view that distinct DR-5-HT pathways regulate neural mechanisms underlying GAD and PD. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Involvement of median raphe nucleus 5-HT1A receptors in the regulation of generalized anxiety-related defensive behaviours in rats

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

Effect of estradiol benzoate microinjection into the median raphe nucleus on contextual conditioning

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

Anxiety-induced antinociception in mice: effects of systemic and intra-amygdala administration of 8-OH-DPAT and midazolam

Rationale: Mice exhibit antinociception after a single experience in the elevated plus maze (EPM), an animal model of anxiety. Objective: This study investigated the mechanisms involved in this form of anxiety-induced antinociception. Methods: Nociception was evaluated by means of the writhing test in mice confined either to the open or enclosed arms of the EPM. The effects of systemic (naloxone, midazolam and 8-OH-DPAT) or intra-amygdala (8-OH-DPAT. NAN-190 and midazolam) drug infusions were investigated in mice previously treated i.p. with 0.6% acetic acid, an algic stimulus that induces abdominal contortions. The effects of these drugs on conventional measures of anxiety (% entries and % time in open arms) in a standard EPM test were also independently investigated. Results: Open-arm confinement resulted in a high-magnitude antinociception (minimum 85%, maximum 450%) compared with enclosed arm confinement. The opiate antagonist naloxone (1 mg/kg and 10 mg/kg) neither blocked this open arm-induced antinociception (OAIA) nor modified indices of anxiety in EPM. Administration of midazolam (0.5-2 mg/kg, s.c.) increased OAIA and produced antinociception in enclosed confined animals, as well as attenuating anxiety in the EPM. The 5-HT(1A) receptor agonist 8-OH-DPAT (0.05-1 mg/kg, s.c.) had biphasic effects on OAIA, antagonising the response at the lowest dose and intensifying it at the highest dose. In addition, low doses of this agent reduced anxiety in the EPM. Although bilateral injections of 8-OH-DPAT (5.6 nmol/0.4 mu l) or NAN-190 (5.6 nmol and 10 nmol/0.4 mu l) into the amygdala did not alter OAIA, increased anxiety was observed in the EPM. In contrast, intra-amygdala administration of midazolam (10 nmol and 30 nmol/0.4 mu l) blocked both OAIA and anxiety. Conclusions: These results with systemic and intracerebral drug infusion suggest that 5-HT(1A) receptors localised in the amygdala are not involved in the pain inhibitory processes that are recruited during aversive situations. However, activation of these receptors does phasically increase anxiety. Although the intrinsic antinociceptive properties of systemically administered midazolam confounded interpretation of its effects on OAIA, intra-amygdala injections of this compound suggest that benzodiazepine receptors in this brain region modulate both the antinociceptive and behavioural (anxiety) responses to the EPM.

Effects of intra-hippocampal infusion of WAY-100635 on plus-maze behavior in mice - Influence of site of injection and prior test experience

The positive profile of systemically-administered 5-HT(1A) receptor antagonists in several rodent models of anxiolytic activity suggests an important role for postsynaptic 5-HT(1A) receptor mechanisms in anxiety. To test this hypothesis, we investigated the effects of WAY-100635 microinfusions (0, 0.1, 1.0 or 3.0 mug in 0.2 mul) into the dorsal (DH) or ventral (VH) hippocampus an behaviours displayed by male Swiss-Webster mice in the elevated plus-maze. As prior experience is known to modify pharmacological responses in this test, the effects of intra-hippocampal infusions were examined both in maze-naive and maze-experienced subjects. Test videotapes were scored for conventional indices of anxiety (% open arm entries/time) and locomotor activity (closed arm entries), as well as a range of ethological measures (e.g. risk assessment). In maze-naive mice, intra-VH (but not intra-M) infusions of WAY-100635 (3.0 mug but not lower doses) increased open arm exploration and reduced risk assessment. These effects were observed in the absence of significant changes in locomotor activity. In contrast, neither intra-VH nor intra-DH infusions of WAY-100635 altered the behaviour of maze-experienced mice. These Findings suggest that postsynaptic 5-HT(1A) receptors in the ventral (but not dorsal) hippocampus play a significant role both in the mediation of plus-maze anxiety in mice and in experientially-induced alterations in responses to this test. (C) 2002 Elsevier B.V. BY All rights reserved.

Anxiogenic-like effects of mCPP microinfusions into the amygdala (but not dorsal or ventral hippocampus) in mice exposed to elevated plus-maze

Serotonin (5-HT) can either increase or decrease anxiety-like behaviour in animals, actions that depend upon neuroanatomical site of action and 5-HT receptor subtype. Although systemic studies with 5-HT(2) receptor agonists and antagonists suggest a facilitatory role for this receptor subtype in anxiety, somewhat inconsistent results have been obtained when such compounds have been directly applied to limbic targets such as the hippocampus and amygdala. The present study investigated the effects of the 5-HT(2B/2C) receptor agonist mCPP bilaterally microinjected into the dorsal hippocampus (DH: 0, 0.3 1.0 or 3.0 nmol/0.2 mu l), the ventral hippocampus (VH: 0, 0.3, 1.0 or 3.0 nmol/0.2 mu l) or the amygdaloid complex (0, 0.15, 0.5, 1.0 or 3.0 nmol/0.1 mu l) in mice exposed to the elevated plus-maze (EPM). Test sessions were videotaped and subsequently scored for conventional indices of anxiety (percentage of open arm entries and percentage of open arm time) and locomotor activity (closed arm entries). Results showed that mCPP microinfusions into the DH or VH failed to affect any behavioural measure in the EPM. However, when injected into the amygdaloid complex, the dose of 1.0 nmol of this 5HT(2B/2C) receptor agonist increased behavioural indices of anxiety without significantly altering general activity levels. This anxiogenic-like effect of mCPP was selectively and completely blocked by local injection of a behaviourally-inactive dose of SDZ SER-082 (10 nmol/0.1 mu l), a preferential 5-HT(2C) receptor antagonist. These data suggest that 5HT(2C) receptors located within the amygdaloid complex (but not the dorsal or ventral hippocampus) play a facilitatory role in plus-maze anxiety in mice. (c) 2007 Elsevier B.V. All rights reserved.

Anxiolytic-like effect of way-100635 microinfusions into the median (but not dorsal) raphe nucleus in mice exposed to the plus-maze: influence of prior test experience

Studies in several laboratories have confirmed the anxiolytic potential of a wide range of 5-HT1A receptor antagonists in rats and mice, with recent evidence pointing to a postsynaptic site of action in the ventral hippocampus. It would, therefore, be predicted that blockade of 5-HT1A somatodendritic autoreceptors in the midbrain raphe nuclei should produce anxiogenic-like effects. To test this hypothesis, we investigated the effects of WAY-100635 microinfusions (0, 1.0 or 3.0 mug in 0.1 mul) into the dorsal (DRN) or median (MRN) raphe nuclei on behaviours displayed by male Swiss-Webster mice in the elevated plus-maze. As this test is sensitive to prior experience. The effects of intra-raphe infusions were examined both in maze-naive and maze-experienced subjects. Sessions, were videotaped and subsequently scored for conventional indices of anxiety (open arm avoidance) and locomotor activity (closed arm entries), as well as a range of ethological measures (e.g. risk assessment). In maze-naive mice, intra-MRN (but not intra-DRN) infusions of WAY-100635 (3.0 mug) increased open arm exploration and reduced risk assessment. Importantly, these effects could not be attributed to a general reduction in locomotor activity. A similar, though somewhat weaker, pattern of behavioural change was observed in maze-experienced animals. This unexpected anxiolytic effect of 5-HT1A autoreceptor blockade in the MRN cannot be accounted fur by a disinhibition of 5-HT release in forebrain targets (e.g. hippocampus and amygdala), where stimulation of postsynaptic 5-HT1A receptors enhances anxiety-like responses. However, as the MRN also projects to the periaqueductal gray matter (PAG), an area known to be sensitive to the anti-aversive effects or 5-HT, it is argued that present results may reflect increased 5-HT release at this crucial midbrain locus within the neural circuitry of defense. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Blockade of 5-HT2 receptors in the periaqueductal grey matter (PAG) abolishes the anxiolytic-like effect of 5-HT1A receptor antagonism in the median raphe nucleus in mice

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

5-HT2 receptor activation in the midbrain periaqueductal grey (PAG) reduces anxiety-like behaviour in mice

It is widely acknowledged that the indoleamine neurotransmitter serotonin (5-HT) plays a dual role in the regulation of anxiety, a role that in part depends upon neuroanatomical locus of action. Thus, whereas stimulation of 5-HT1A or 5-HT2 receptors in the limbic forebrain (amygdala, hippocampus) enhances anxiety-like responding in rodents, activation of corresponding receptor populations in the midbrain periaqueductal grey (PAG) more often than not reduce anxiety-like behaviour. The present study specifically concerns the anxiety-modulating influence of 5-HT2 receptors within the mouse PAG. Experiment 1 assessed the effects of intra-PAG infusions of the 5-HT2B/2C receptor agonist mCPP (0, 0.03, 0.1 or 0.3 nmol/0.1 mu l) on the behaviour of mice exposed to the elevated plus-maze. As mCPP acts preferentially at 5-HT2B and 5-HT2C receptors, Experiment 2 investigated its effects in animals pretreated with ketanserin, a preferential 5-HT2A/2C receptor antagonist. In both cases, test sessions were videotaped and subsequently, scored for anxiety-like behaviour (e.g., percentage of open arm entries and percentage of open arm time) as well as general locomotor activity (closed arm entries). The results of Experiment I showed that mCPP microinfusions (0.03 and 0.1 nmol) into the PAG of mice decreased behavioural indices of anxiety without significantly altering general activity measures. In Experiment 2, the anxiolytic-like profile of intra-PAG mCPP (0.03 nmol) was substantially attenuated by intra-PAG pretreatment with an intrinsically inactive dose of the preferential 5-HT2A/2C receptor antagonist, ketanserin (10 nmol/0.1 mu l). Together, these data suggest that 5HT(2C) receptor populations within the midbrain PAG play an inhibitory role in plus-maze anxiety in mice. (C) 2007 Elsevier B.V. All rights reserved.

Estrutura genética de populações de Amphobotrys ricini, agente causal do mofo cinzento da mamoneira

The gray mold, causal organism Amphobotrys ricini, is one of the major diseases of castor bean. Difficulties in managing plant disease arises form the limited understanding of the genetic structure of A. ricini, their complexity and variability make it difficult to control. Genetic structure can be used to infer the relative impact of different forces that influence the evolution of pathogen populations, that allow to predict the potencial for pathogen populations to envolve in agricultural ecosystems. Growers protect their crop by applying fungicides, but there aren t fungicides to provide significant control of gray mold of castor bean. The objectives of this work were use RAPD to determine the genetic structure of A. ricini subpopulations in Paraíba and assay the sensitivity of A. ricini isolates to azoxystrobin and carbendazim. To determine the genetic structure of A. ricini subpopulations in Paraíba, 23 isolates were colleted from two different geographic location (subpopulation). These isolates were analysed by RAPD using 22 random decamer primers, purchased from OPERON, produced a total of 80 markers polimorphics. The resulting matrixes were analysed using PopGene version 1.32. Sensitivity to azoxystrobin and carbendazim of 30 isolates, colleted form Paraíba and Alagoas, was estimated based on spore germination and colony growth inhibition. The stock solutions were added toV8 medium after sterilization to produce final concentrations of 0, 0.01, 0.1, 1, 10, and 100 µg/ml of carbendazim and 0, 0.001, 0.01, 0.1, 1, and 10 µg/ml of azoxystrobin. All statistical analyses were performed using SAS to estimate the dose that inhibited fungal growth by 50% (ED50 values). The genetic diversity within subpopulations (Hs=0,271) accounted for 92% of the total genetic diversity (Ht=0,293), while genetic diversity between subpopulations (Gst = 0,075) represented only 7,5%. The estimated number of migrants per generation (NM ) was 6,15. Nei s average gene identity across 80 RAPD loci was 0,9468. Individual ED50 values, for the 30 isolates screened for their sensitivity to azoxystrobin, ranged From a maximum of 0,168 µg/ml to a minimum of 0,0036 µg/ml. The ED50 values for carbendazim varied within the range of 0,026 to 0,316 µg/ml

Efeitos da senescência no núcleo supraquiasmático do sagui (Callithrix Jacchus): plasticidade morfológica e neuroquímica

The circadian timing system (CTS) is responsible for the generation and synchronization and the suprachiasmatic nucleus (SCN) of the hypothalamus has been described as the major circadian pacemaker in many mammalian species. The internal temporal organization managed by SCN is disturbed with aging bringing many pathological disorders that range from loss of complex cognitive performance to simple physiological functions. Therefore, our aim was perform a comparative study of the morphological aspects and neurochemical composition in the SCN of marmosets (Callithrix jacchus) adults and older using immunohistochemical techniques. We found morphometric and neurochemical changes in th SCN o folder animals in comparison to adults, among these a possible decreased in retinal projection to the SCN of older animals, found through a decline in CTB immunostaining, which can occur due atrophy and/or decreasing of fibers from the retinohypothalamic tract (RHT). The Klüver-Barrera histological technique strongly suggests a decrease in those fibers from RHT. Also, by means of a morphometric study, it is found a atrophy and numerical decline of neurons in SCN of aged animals, investigated by Nissl technique, and immunostaining with NeuN and calbindin. Relative optical density (ROD) analysis were used to evaluate the expression of some neurochemical components in SCN, such as GFAP expression, which was increased in older, result that indirectly reinforces that morphological changes occurs due the aging; the vasoactive intestinal polipeptide (VIP) showed no expression alteration in SCN of older animals; the serotonin (5-HT) was descreased in the dorsomedial portion of the SCN, and neurpeptide Y (NPY) apparently also decrease due to the increase of age. Many of these modifications were seen in other animals, such as rodents, human primates and non-human primates. These data about marmoset comes to add new information of the effect of aging on structures responsibles for the circadian rhytmicity, and that some behavioral changes controlled by th SCN, and founded in aged animals, may be caused by these morphological and neurochemical changes. Although some results have been quantitatively negative, qualitatively all analysis show significant change comparing adult and older animals, perhaps due to a low sampling number. In conclusion, the marmoset presents several morphological and neurochemical changes in the SCN of aged animals compared to adults, which may result in behavioral changes that favor pathology aging related

Centros rombencefálicos de processamento auditivo do sagui (Callithrix jacchus): uma análise citoarquitetônica e neuroquímica

The auditory system is composed by a set of relays from the outer ear to the cerebral cortex. In mammals, the central auditory system is composed by cochlear nuclei, superior olivary complex, inferior colliculus and medial geniculate body. In this study, the auditory rombencephalic centers, the cochlear nuclear complex and the superior olivary complex were evaluated from the cytoarchitecture and neurochemical aspects, thorough Nissl staining and immunohistochemical techniques to reveal specific neuron nuclear protein (NeuN), glutamate (Glu), glutamic acid decarboxilase (GAD), enkephalin (ENK), serotonin (5-HT), choline acetyltransferase (ChAT) and calcium-binding proteins calbindin (CB), calretinin (CR), and parvalbumin (PV). The common marmoset (Callithrix jacchus), a little native primate of the Brazilian atlantic forest was used as an experimental animal. As results, it was noted that the cochlear nuclear complex is composed by anteroventral, posteroventral and dorsal nuclei, and the superior olivary complex is constituted by the lateral and medial superior olivary nuclei and the trapezoid body nucleus. Glu, GAD, ENK, ChAT, CB, CR, PV-immunoreactive cells, fibers and terminals besides besides only 5-HT terminals were found unhomogeneously in all nuclei, of both complex. The emerging data are discussed in a comparative and functional context, and represent an important contribution to knowledge of the central auditory pathways in the common marmoset, and then in primates