108 resultados para Plant Physiological Phenomena
Resumo:
The Miconia genus, a plant widely used for medicine, occurs in tropical America and its extracts and isolated compounds have demonstrated antibiotic, antitumoral, analgesic and antimalarial activities. However, no study concerning its genotoxicity has been conducted and it is necessary to determine its potential mutagenic effects to develop products and chemicals from these extracts. This study assessed the cytotoxicity, mutagenicity and the protective effects of methanolic extracts from Miconia species on Chinese hamster lung fibroblast cell cultures (V79). The cytotoxicity was evaluated using a clonogenic assay. Cultures exposed to the extract of Miconia albicans up to a concentration of 30 mu g/mL, M. cabucu up to 40 mu g/mL, M. albicans up to 40 mu g/mL and M. stenostachya up to 60 mu g/mL exhibited a cytotoxic effect on the cells. The clonogenic assay used three non-cytotoxic concentrations (5, 10 and 20 mu g/mL) to evaluate mutagenicity and antimutagenicity of the extracts. Cultures were treated with these three extract concentrations (mutagenicity test) or the extract associated with doxorubicin (DXR) (antimutagenicity test) in three protocols (pre-, simultaneous and post-treatments). Distilled water and DXR were used as negative and positive controls, respectively. In the micronucleus (MN) test, a significant reduction was observed in MN frequency in cultures treated with DXR and extracts compared to those receiving only DXR; a significant reduction was also observed for the presence of mutagenicity in all treatments. This study confirmed the safe use of Miconia extracts at the concentrations tested and reinforced the therapeutic properties previously described for Miconia species by showing their protective effects on doxorubicin-induced mutagenicity. (C) 2010 Elsevier GmbH. All rights reserved.
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Microbial xylanolytic enzymes have a promising biotechnological potential, and are extensively applied in industries. In this study, induction of xylanolytic activity was examined in Aspergillus phoenicis. Xylanase activity induced by xylan, xylose or beta-methylxyloside was predominantly extracellular (93-97%). Addition of 1% glucose to media supplemented with xylan or xylose repressed xylanase production. Glucose repression was alleviated by addition of cAMP or dibutyryl-cAMP. These physiological observations were supported by a Northern analysis using part of the xylanase gene ApXLN as a probe. Gene transcription was shown to be induced by xylan, xylose, and beta-methylxyloside, and was repressed by the addition of 1% glucose. Glucose repression was partially relieved by addition of cAMP or dibutyryl cAMP.
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Soil salinity is a major abiotic stress influencing plant productivity worldwide. Schinopsis quebracho colorado is one of the most important woody species in the Gran Chaco, an and and salt-prone subtropical biome of South America. To gain a better understanding of the physiological mechanisms that allow plant establishment under salt conditions, germination and seedling growth of S. quebracho colorado were examined under treatment with a range of NaCl solutions (germination: 0-300 mmol l(-1) NaCl; seedling growth: 0-200 mmol l(-1) NaCl). The aim was to test the hypothesis that S. quebracho colorado is a glycophite that shows different salt tolerance responses with development stage. Proline content, total soluble carbohydrates and Na+, K+ and Cl- concentrations in leaves and roots of seedlings, and the chlorophyll concentration and relative water content of leaves were measured. Germination was not affected by 100 mmol l(-1) NaCl, but decreased at a concentration of 200 mmol l(-1). At 300 mmol l(-1) NaCl, germination did not occur. Seedling growth decreased drastically with increasing salinity. An increase in NaCl from 0 to 100 mmol l(-1) also significantly reduced the leaf relative water content by 22% and increased the proline concentration by 60% in roots. In contrast, total soluble carbohydrates were not significantly affected by salinity. Seedlings showed a sodium exclusion capacity, and there was an inverse correlation between Cl- concentration and the total chlorophyll concentration. S. quebracho colorado was more tolerant to salinity during germination than in the seedling phase. The results suggest that this increased tolerance during germination might, in part, be the result of lower sensitivity to high tissue Na+ concentrations. The significant increment of proline in the roots suggests the positive role of this amino acid as a compatible solute in balancing the accumulation of Na+ and Cl- as a result of salinity. These results help clarify the physiological mechanisms that allow establishment of S. quebracho colorado on salt-affected soils in arid and semi-arid Gran Chaco. (c) 2008 Elsevier Ltd. All rights reserved.
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The metallic voice is usually confused with ring or nasality by singers and nontrained listeners. who are not used to perceptual vocal analysis. They believe a metallic voice results from a rise in fundamental frequency. A diagnostic error in this aspect may lead to lowering pitch, an incorrect procedure that Could Cause vocal overload and fatigue. The purpose of this article is to Study the quality of metallic voice considering the correlation between information of the physiological and acoustic plans, based on a perceptive consensual assumption. Fiberscopic video pharyngolaryngoscopy was performed on 21 professional singers while speaking vowel [e]-in normal and metallic modes to observe muscular movements and structural changes of the velopharynx, pharynx, and larynx. Vocal samples captured simultaneously to the fiberscopic examination were acoustically analyzed. Frequency and amplitude of the first four formants (F(1), F(2), F(3), and F(4)) were extracted by means of linear predictor coefficients (LPC) Spectrum and were statistically analyzed. Vocal tract adjustments such as velar lowering, pharyngeal wall narrowing, laryngeal rise, aryepiglottic, and lateral laryngeal constrictions were frequently found: there were no significant changes in frequency and amplitude of F(1) in the metallic voiced there were significant increases in amplitudes of F(2), F(3), and F(4) and in frequency for F, metallic Voice perceived as louder was correlated to an increase ill amplitude of F(3) and F(4). Physiological adjustments of velopharynx, pharynx, and larynx are combined in characterizing the metallic voice and can be acoustically related to changes in formant pattern.
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Introduction: Although obsessions and compulsions comprise the main features of obsessive-compulsive disorder (OCD), many patients report that their compulsions are preceded by a sense of ""incompleteness"" or other unpleasant feelings such as premonitory urges or a need perform action`s until feeling ""just right."" These manifestations have been characterized as Sensory Phenomena (SP). The current study presents initial psychometric data for a new scale designed to measure SP. Methods: Seventy-six adult OCD subjects were probed twice. Patients were assessed with an open clinical interview (considered as the ""gold standard"") and with the following standardized instruments: Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis I Disorders, Yale-Brown Obsessive-Compulsive Scale, Dimensional Yale-Brown Obsessive-Compulsive Scale, Yale Global Tic Severity Scale, Beck Anxiety Inventory, and Beck Depression Inventory. Results: SP were present in 51 OCD patients (67.1%). Tics were present in 16 (21.1%) of the overall sample. The presence of SP was significantly higher in early-onset OCD patients. There were no significant differences in the presence of SP according to comorbidity with tics or gender. The comparison between the results from the open clinical interviews and the University of Sao Paulo Sensory Phenomena Scale (USP-SPS) showed an excellent concordance between them, with no significant differences between interviewers. The inter-rater reliability between the expert raters for the USP-SPS was high, with K=.92. The Pearson correlation coefficient between the SP severity scores given by the two raters was .89. Conclusion: Preliminary results suggest that the USP-SPS is a valid and reliable instrument for assessing the presence and severity of SP in OCD subjects. CNS Spectr. 2009;14(6):315-323
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Introduction: A variety of subjective experiences have been reported to be associated with the symptom expression of obsessive-compulsive disorder (OCD) and Tourette syndrome (TS). First described in TS patients, these subjective experiences have been defined in different ways. There is no consensus in the literature on how to best define subjective experiences. This lack of consensus may hinder the understanding of study results and prevents the possibility of including them in the search for etiological factors associated with OCD and TS. Methods: The objective of this article was to review the descriptions of subjective experiences in the English-language literature from 1980-2007. This meta-analytic review was carried out using the English-language literature from 1980-2007 available on MEDLINE, PsycINFO, and the Cochrane Library databases using the following search terms: premonitory urges, sensory tics, ""just-right"" perceptions, sensory phenomena, sensory experiences, incompleteness, ""not just-right"" phenomena, obsessive-compulsive disorder and TS, including OCD and/or TS, in all combination searches. We also searched for the references cited in each article previously found that referred to the aforementioned terms. Thirty-one articles were included in the study. Results: Subjective experiences, in particular, the sensory phenomena, were important phenotypic variables in the characterization of the tic-related OCD subtype and were more frequent in the early-onset OCD subtype. There is a paucity of studies using structured interviews to assess sensory phenomena, their epidemiology and the etiological mechanisms associated with sensory phenomena. Conclusion: The current review provides some evidence that sensory phenomena can be useful to identify more homogenous subgroups of OCD and TS patients and should be included as important phenotypic variables in future clinical, genetic, neuroimaging, and treatment-response studies.
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Water deficit and ABA application on leaf gas exchange and flavonoid content in marigold (Calendula officinalis L.).The goal of this study was to evaluate the effects of water deficit and abscisic acid (ABA) application on physiological parameters and flavonoid production in marigold plant. The experiment was performed under nursery conditions with potted plants. It was tested water deficit by withholding water (control - diary irrigation, 3, 6 and 9 days without irrigation) followed by 3 ABA concentrations (0, 10 e 100 mu M) applied in the beginning of blooming. It was evaluated the relative water content and the leaf gas exchange using a portable infrared gas analyzer (A: net photosynthesis, gs: stomatal conductance, E: transpiration, Ci: CO(2) intercellular concentration and EUA: water use efficiency). At the end of 9 days of water deficit there were significant decreases in all the characteristics evaluated, independent of ABA application. This suggests that the main effect of ABA was to cause a reduction on gs which was accompanied of a reduction in A, only when the plants were submitted to the water deficit. There was no significant difference among the levels of water deficit tested in relation to the total flavonoid content in inflorescences. However, ABA restricted the flavonoids biosynthesis both in control plant and stressed plants.
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Background: In view of conflicting neuroimaging results regarding autonomic-specific activity within the anterior cingulate cortex (ACC), we investigated autonomic responses to direct brain stimulation during sterecitactic limbic surgery. Methods: Skin conductance activity and accelerative heart rate responses to multi-voltage stimulation of the ACC (n = 7) and paralimbic subcauclate (n = 5) regions were recorded during bilateral anterior cingulotomy and bilateral subcauclate tractotomy (in patients that had previously received an adequate lesion in the ACC), respectively. Results: Stimulations in both groups were accompanied by increased autonomic arousal. Skin conductance activity was significantly increased during ACC stimulations compared with paralimbic targets at 2 V (2.34 +/- .68 [score in microSiemens +/- SE] vs. .34 +/- .09, p = .013) and 3 V (3.52 +/- .86 vs. 1.12 +/- .37, p = .036), exhibiting a strong ""voltage-response"" relationship between stimulus magnitude and response amplitude (difference from 1 to 3 V = 1.15 +/- .90 vs. 3.52 +/- .86, p = .041). Heart rate response was less indicative of between-group differences. Conclusions: This is the first study of its kind aiming at seeking novel insights into the mechanisms responsible for central autonomic modulation. It supports a concept that interregional interactions account for the coordination of autonomic arousal.
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Background: The aim of the study was to investigate how perfectionism and sensory phenomena (SP) interact as possible phenotypic components of obsessive-compulsive disorder (OCD). Methods: Forty-seven adult outpatients, meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for OCD, and a control group of 41 community subjects were assessed using the Frost Multidimensional Perfectionism Scale (FM PS), the University of Sao Paulo-Sensory Phenomena Scale, and other standard measures of OCD severity. Results: Three of the FMPS subscales (""concern over mistakes,"" ""doubts about action,"" and ""parental criticism"") were significantly different between OCD patients and control subjects. All subtypes of SP were significantly more frequent and more severe in OCD than in control subjects. The ""incompleteness"" subtype of SP was associated with high scores on all dimensions of the FMPS, whereas the ""just-right"" subtype of SP was only associated with ""doubts about action,"" ""personal standards,"" and ""organization"" subscales of the FMPS. Conclusions: Presence and severity of SP and specific elements of perfectionism clearly distinguish OCD patients from healthy control subjects. Some SP subtypes are associated with specific FPMS subscale scores, whereas others are not. These results emphasize the relevance of assessing different subtypes of perfectionism and SP in OCD patients as important subcomponents of the OCD phenotype. (C) 2009 Elsevier Inc. All rights reserved.
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Yogi A, Callera GE, Tostes R, Touyz RM. Bradykinin regulates calpain and proinflammatory signaling through TRPM7-sensitive pathways in vascular smooth muscle cells. Am J Physiol Regul Integr Comp Physiol 296: R201-R207, 2009. First published September 17, 2008; doi: 10.1152/ajpregu.90602.2008.-Transient receptor potential melastatin-7 (TRPM7) channels have recently been identified to be regulated by vasoactive agents acting through G protein-coupled receptors in vascular smooth muscle cells (VSMC). However, downstream targets and functional responses remain unclear. We investigated the subcellular localization of TRPM7 in VSMCs and questioned the role of TRPM7 in proinflammatory signaling by bradykinin. VSMCs from Wistar-Kyoto rats were studied. Cell fractionation by sucrose gradient and differential centrifugation demonstrated that in bradykinin-stimulated cells, TRPM7 localized in fractions corresponding to caveolae. Immunofluorescence confocal microscopy revealed that TRPM7 distributes along the cell membrane, that it has a reticular-type intracellular distribution, and that it colocalizes with flotillin-2, a marker of lipid rafts. Bradykinin increased expression of calpain, a TRPM7 target, and stimulated its cytosol/membrane translocation, an effect blocked by 2-APB (TRPM7 inhibitor) and U-73122 (phospholipase C inhibitor), but not by chelerythrine (PKC inhibitor). Expression of proinflammatory mediators VCAM-1 and cyclooxygenase-2 (COX-2) was time-dependently increased by bradykinin. This effect was blocked by Hoe-140 (B(2) receptor blocker) and 2-APB. Our data demonstrate that in bradykinin-stimulated VSMCs: 1) TRPM7 is upregulated, 2) TRPM7 associates with cholesterol-rich microdomains, and 3) calpain and proinflammatory mediators VCAM-1 and COX2 are regulated, in part, via TRPM7- and phospholipase C-dependent pathways through B2 receptors. These findings identify a novel signaling pathway for bradykinin, which involves TRPM7. Such phenomena may play a role in bradykinin/B(2) receptor-mediated inflammatory responses in vascular cells.
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The alarm response to skin extract has been well documented in fish. In response to skin extract, there is a decline in both locomotion activity and aggressive interactions. Our observation herein of these responses in the cichlid Nile tilapia, Oreochromis niloticus, confirmed the existence of the alarm response in this species. However, so far there has been a paucity of information on the autonomic correlates of this response. In this study, the ventilatory change in response to the chemical alarm cue was evaluated. This parameter was measured 4 min before and 4 min after exposure to 1 mL of either conspecific skin extract or distilled water (extract vehicle). Skin extract induced an increase in the ventilation rate, which suggested an anticipatory adjustment to potentially harmful stimuli. The chemical cue (alarm substance) also interfered with the prioritisation of responses to different environmental stimuli (stimuli filtering); this was suggested by the observation that the Nile tilapia declined to fight after exposure to a cue that indicates a risk of predation. Furthermore, histological analysis of the Nile tilapia skin revealed the presence of putative alarm substance-producing (club) cells.
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Molkov YI, Zoccal DB, Moraes DJ, Paton JF, Machado BH, Rybak IA. Intermittent hypoxia-induced sensitization of central chemoreceptors contributes to sympathetic nerve activity during late expiration in rats. J Neurophysiol 105: 3080-3091, 2011. First published April 6, 2011; doi:10.1152/jn.00070.2011.-Hypertension elicited by chronic intermittent hypoxia (CIH) is associated with elevated activity of the thoracic sympathetic nerve (tSN) that exhibits an enhanced respiratory modulation reflecting a strengthened interaction between respiratory and sympathetic networks within the brain stem. Expiration is a passive process except for special metabolic conditions such as hypercapnia, when it becomes active through phasic excitation of abdominal motor nerves (AbN) in late expiration. An increase in CO(2) evokes late-expiratory (late-E) discharges phase-locked to phrenic bursts with the frequency increasing quantally as hypercapnia increases. In rats exposed to CIH, the late-E discharges synchronized in AbN and tSN emerge in normocapnia. To elucidate the possible neural mechanisms underlying these phenomena, we extended our computational model of the brain stem respiratory network by incorporating a population of presympathetic neurons in the rostral ventrolateral medulla that received inputs from the pons, medullary respiratory compartments, and retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG). Our simulations proposed that CIH conditioning increases the CO(2) sensitivity of RTN/pFRG neurons, causing a reduction in both the CO(2) threshold for emerging the late-E activity in AbN and tSN and the hypocapnic threshold for apnea. Using the in situ rat preparation, we have confirmed that CIH-conditioned rats under normal conditions exhibit synchronized late-E discharges in AbN and tSN similar to those observed in control rats during hypercapnia. Moreover, the hypocapnic threshold for apnea was significantly lowered in CIH-conditioned rats relative to that in control rats. We conclude that CIH may sensitize central chemoreception and that this significantly contributes to the neural impetus for generation of sympathetic activity and hypertension.
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Plant-antivenom is a computational Websystem about medicinal plants with anti-venom properties. The system consists of a database of these plants, including scientific publications on this subject and amino acid sequences of active principles from venomous animals. The system relates these data allowing their integration through different search applications. For the development of the system, the first surveys were conducted in scientific literature, allowing the creation of a publication database in a library for reading and user interaction. Then, classes of categories were created, allowing the use of tags and the organization of content. This database on medicinal plants has information such as family, species, isolated compounds, activity, inhibited animal venoms, among others. Provision is made for submission of new information by registered users, by the use of wiki tools. Content submitted is released in accordance to permission rules defined by the system. The database on biological venom protein amino acid sequences was structured from the essential information from National Center for Biotechnology Information (NCBI). Plant-antivenom`s interface is simple, contributing to a fast and functional access to the system and the integration of different data registered on it. Plant-antivenom system is available on the Internet at http://gbi.fmrp.usp.br/plantantivenom.
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Generalized Social Anxiety Disorder (SAD) is one of the most common anxiety conditions with impairment in social life. Cannabidiol (CBD), one major non-psychotomimetic compound of the cannabis sativa plant, has shown anxiolytic effects both in humans and in animals. This preliminary study aimed to compare the effects of a simulation public speaking test (SPST) on healthy control (HC) patients and treatment-naive SAD patients who received a single dose of CBD or placebo. A total of 24 never-treated patients with SAD were allocated to receive either CBD (600 mg; n = 12) or placebo (placebo; n = 12) in a double-blind randomized design 1 h and a half before the test. The same number of HC (n = 12) performed the SPST without receiving any medication. Each volunteer participated in only one experimental session in a double-blind procedure. Subjective ratings on the Visual Analogue Mood Scale (VAMS) and Negative Self-Statement scale (SSPS-N) and physiological measures (blood pressure, heart rate, and skin conductance) were measured at six different time points during the SPST. The results were submitted to a repeated-measures analysis of variance. Pretreatment with CBD significantly reduced anxiety, cognitive impairment and discomfort in their speech performance, and significantly decreased alert in their anticipatory speech. The placebo group presented higher anxiety, cognitive impairment, discomfort, and alert levels when compared with the control group as assessed with the VAMS. The SSPS-N scores evidenced significant increases during the testing of placebo group that was almost abolished in the CBD group. No significant differences were observed between CBD and HC in SSPS-N scores or in the cognitive impairment, discomfort, and alert factors of VAMS. The increase in anxiety induced by the SPST on subjects with SAD was reduced with the use of CBD, resulting in a similar response as the HC. Neuropsychopharmacology (2011) 36, 1219-1226; doi: 10.1038/npp.2011.6; published online 9 February 2011
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The chronic mild stress (CMS) model has been used as an animal model of depression which induces anhedonic behavior in rodents. The present study was aimed to evaluate the behavioral and physiological effects of administration of P-carboline harmine in rats exposed to CMS Procedure. To this aim, after 40 days of exposure to CMS procedure, rats were treated with harmine (15 mg/kg/day) for 7 days. In this study, sweet food consumption, adrenal gland weight, adrenocorticotrophin hormone (ACTH) levels, and hippocampal brain-derived-neurotrophic factor (BDNF) protein levels were assessed. Our findings demonstrated that chronic stressful situations induced anhedonia, hypertrophy of adrenal gland weight, increase ACTH circulating levels in rats and increase BDNF protein levels. Interestingly, treatment with harmine reversed anhedonia, the increase of adrenal gland weight, normalized ACTH circulating levels and BDNF protein levels. Finally, these findings further support the hypothesis that harmine could be a new pharmacological tool for the treatment of depression. (C) 2009 Elsevier Inc. All rights reserved.