228 resultados para Secondary growth bulbs


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Six antifungal agents at subinhibitory concentrations were used for investigating their ability to affect the growth and branching in Neurospora crassa. Among the antifungals herein used, the azole agent ketoconazole at 0.5 mu g/ml inhibited radial growth more than fluconazole at 5.0 mu g/ml while amphotericin B at 0.05 mu g/ml was more effective than nystatin at 0.05 mu g/ml. Morphological alterations in hyphae were observed in the presence of griseofulvin, ketoconazole and terbinafine at the established concentrations. The antifungal agents were more effective on vegetative growth than on conidial germination. Terbinafine markedly reduced growth unit length (GU) by 54.89%, and caused mycelia to become hyperbranched. In all cases, there was a high correlation between hyphal length and number of tips (r > 0.9). All our results showed highly significant differences by ANOVA, (p < 0.001, alpha = 0.05). Considering that the hyphal tip is the main interface between the fungus and its environment/through which enzymes and toxins are secreted and nutrients absorbed, it would not be desirable to obtain a hyperbranched mycelia with inefficient doses of antifungal drugs.

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The effects of PLC and Pkc inhibitors on Aspergillus nidulans depend on the carbon source. PLC inhibitors Spm and C48/80 delayed the first nuclear division in cultures growing on glucose, but stimulated it in media supplemented with pectin. Less intense were these effects on the mutant transformed with PLC-A gene rupture (AP27). Neomycin also delayed the germination in cultures growing on glucose or pectin; however, on glucose, the nuclear division was inhibited whereas in pectin it was stimulated. These effects were minor in AP27. The effects of Ro-31-8425 and BIM (both Pkc inhibitors) were also opposite for cultures growing on glucose or pectin. On glucose cultures of both strains BIM delayed germination and the first nuclear division, whereas on pectin both parameters were stimulated. Opposite effects were also detected when the cultures were growing on glucose or pectin in the presence of Ro-31-8425.

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Leukotrienes (LTs) are potent lipid mediators involved in the control of host defense. LTB(4) induces leukocyte accumulation, enhances phagocytosis and bacterial clearance, and increases NO synthesis. LTB(4) is also important in early effector T cell recruitment that is mediated by LTB(4) receptor 1, the high-affinity receptor for LTB(4). The aims of this study were to evaluate whether LTs are involved in the secondary immune response to vaccination in a murine model of Histoplasma capsulatum infection. Our results demonstrate that protection of wild-type mice immunized with cell-free Ags from H. capsulatum against histoplasmosis was associated with increased LTB(4) and IFN-gamma production as well as recruitment of memory T cells into the lungs. In contrast, cell-free Ag-immunized mice lacking 5-lipoxygenase(-/-), a critical enzyme involved in LT synthesis, displayed a marked decrease on recruitment of memory T cells to the lungs associated with increased synthesis of TGF-beta as well as IL-10. Strikingly, these effects were associated with increased mortality to 5-lipoxygenase(-/-)-infected mice. These data establish an important immunomodulatory role of LTs, in both the primary and secondary immune responses to histoplasmosis. The Journal of Immunology, 2008,181: 8544-8551.

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Light conditions during mycelial growth are known to influence fungi in many ways. The effect of visible-light exposure during mycelial growth was investigated on conidial tolerance to UVB irradiation and wet heat of Metarhizium robertsii, an insect-pathogenic fungus. Two nutrient media and two light regimens were compared. Conidia were produced on (A) potato dextrose agar plus yeast extract medium (PDAY) (A1) under dark conditions or (A2) under continuous visible light (provided by two fluorescent lamps with intensity 5.4 W m-2). For comparison, the fungus was also produced on (B) minimal medium (MM) under continuous-dark incubation, which is known to produce conidia with increased tolerance to heat and UVB radiation. The UVB tolerances of conidia produced on PDAY under continuous visible light were twofold higher than conidia produced on PDAY medium under dark conditions, and this elevated UVB tolerance was similar to that of conidia produced on MM in the dark. The heat tolerance of conidia produced under continuous light was, however, similar to that of conidia produced on MM or PDAY in the dark. Conidial yield on PDAY medium was equivalent when the fungus was grown either under continuous-dark or under continuous-light conditions.

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Fungi, including the entomopathogenic deuteromycete Metarhizium anisopliae, produce a wide diversity of secondary metabolites that either can be secreted or stored in specific developmental structures, e.g., conidia. Some secondary metabolites, such as pigments, polyols and mycosporines, are associated with pathogenicity and/or fungal tolerance to several stress-inducing environmental factors, including temperature and solar radiation extremes. Extracts of M. anisopliae var. anisopliae (strain ESALQ-1037) conidia were purified by chromatographic procedures and the isolated compounds analyzed by (1)H and (13)C nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. LC-MS analyses were carried out to search for mycosporines (the initial targets), but no compounds of this class were detected. A molecule whose natural occurrence was previously undescribed was identified. It consists of betaine conjugated with tyrosine, and the structure was identified as 2-([1-carboxy-2-(4-hydroxyphenyl)ethyl]amino)-N,N,N-trimethyl-2-oxoethanammonium. mannitol was the predominant compound in the alcoholic conidial extract, but no amino acids other than tyrosine were found to be conjugated with betaine in conidia. The fungal tyrosine betaine was detected also in conidial extracts of three other M. anisopliae var. anisopliae (ARSEF 1095, 5626 and 5749) and three M. anisopliae var. acridum isolates (ARSEF 324, 3391 and 7486), but it was not detected in Aspergillus nidulans conidial extract (ATCC 10074). (C) 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

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Lichen phenolic compounds exhibit antioxidant, antimicrobial, antiproliferative. and cytotoxic activities. The purpose of this study was to evaluate the anticancer activity of lecanoric acid, a secondary metabolite of the lichen Parmotrema tinctorum, and its derivatives, orsellinates, obtained by structural modification. A cytotoxicity assay was carried out hi vitro with sulforhodamine B (SRB) using HEp-2 larynx carcinoma, MCF7 breast carcinoma, 786-0 kidney carcinoma, and B16-F10 murine melanoma cell lines, in addition to a normal (Vero) cell line in order to calculate the selectivity index of the compounds. n-Butyl orsellinate was the most active compound, with IC(50) Values (the concentration that inhibits 50% of growth) ranging from 7.2 to 14.0 mu g/ml, against all the cell lines tested. The compound was more active (IC(50), = 11.4 mu g/mL) against B16-F10 cells than was cisplatin (12.5 mu g/mL). Conversely, lecanoric acid and methyl orsellinate were less active against all cell lines, having an IC(50) value higher than 50 mu g/mL. Ethyl orsellinate was more active against HEp-2 than against MCF7, 786-0, or B16-F10 cells. The same pattern was observed for n-propyl and n-butyl orsellinates. n-Pentyl orsellinate was less active than n-propyl or n-butyl orsellinates against HEp-2 cells. The orsellinate activity increased with chain elongation (from methyl to n-butyl), a likely consequence of an increase in lipophilicity. The results revealed that the structural modification of lecanoric acid increases the cytotoxic activity of the derivatives tested.

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This paper contributes to the literature on balance-of-payments constrained growth by investigating how structural change identified with changes in the sectoral composition of exports and imports affects the external constraint We test both the original and a multisectoral version of Thirlwall`s law for a sample of Latin American and Asian countries The original Thirlwall s law is found to hold for all sample countries except South Korea, whereas the multisectoral analogue holds for all of them As the sectoral composition of exports and imports is found to matter for growth we analyze the evolution of each country`s weighted trade income elasticities

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Despite Latin America`s dismal performance between the 1950s and 1980s, the region experienced strong capital deepening. We suggest that these facts can be explained as a consequence of the restrictive trade regime adopted at that time. Our framework is based on a dynamic Heckscher-Ohlin model, with scale economies in the capital-intensive sector. Initially, the economy is open and produces only the labor-intensive good. The trade regime is modeled as a move to a closed economy. The model produces results consistent with the Latin American experience. Specifically, a Sufficiently small Country experiences no long-run income growth, but an increase in capital. (C) 2009 Elsevier B.V. All rights reserved.

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In 1997, Brazil approved law n(cr) 9478, establishing new rules for sharing petroleum royalties with Brazilian municipalities. The goal of this paper is to evaluate whether royalties distributed under the new law have contributed for the development of benefited municipalities. For that the difference-indifferences estimator (diff-in-diff) is used, which compares the evolution of the economic product into the municipality affected by the new law with the unaffected ones, by exploring the new legislation as an exogenous change. The data refer to the municipal gross domestic product (GDP) growth rate before and after the event. Results are surprising, showing that royalty receivers grew less than municipalities that did not receive such resources. The difference is small but statistically significant. In general, an increase of one real in royalties per capita reduces the growth rate of the municipal product in 0.002 percentile points. (C) 2009 Elsevier Ltd. All rights reserved.

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Aim The aim of this study was to assess the causal mechanisms underlying populational subdivision in Drosophila gouveai, a cactophilic species associated with xeric vegetation enclaves in eastern Brazil. A secondary aim was to investigate the genetic effects of Pleistocene climatic fluctuations on these environments. Location Dry vegetation enclaves within the limits of the Cerrado domain in eastern Brazil. Methods We determined the mitochondrial DNA haplotypes of 55 individuals (representing 12 populations) based on sequence data of a 483-bp fragment from the cytochrome c oxidase subunit II (COII) gene. Phylogenetic and coalescent analyses were used to test for the occurrence of demographic events and to infer the time of divergence amongst genetically independent groups. Results Our analyses revealed the existence of two divergent subclades (G1 and G2) plus an introgressed clade restricted to the southernmost range of D. gouveai. Subclades G1 and G2 displayed genetic footprints of range expansion and segregated geographical distributions in south-eastern and some central highland regions, east and west of the Parana River valley. Molecular dating indicated that the main demographic and diversification events occurred in the late to middle Pleistocene. Main conclusions The phylogeographical and genetic patterns observed for D. gouveai in this study are consistent with changes in the distribution of dry vegetation in eastern Brazil. All of the estimates obtained by molecular dating indicate that range expansion and isolation pre-dated the Last Glacial Maximum, occurring during the late to middle Pleistocene, and were probably triggered by climatic changes during the Pleistocene. The current patchy geographical distribution and population subdivision in D. gouveai is apparently closely linked to these past events.

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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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There are practical and academic situations that justify the study of calcium carbonate crystallization and especially of systems that are associated with organic matrices and a confined medium. Despite the fact that many different matrices have been studied, the use of well-behaved, thin organic films may provide new knowledge about this system. In this work, we have studied the growth of calcium carbonate particles on well-defined organic matrices that were formed by layer-by-layer (LbL) polyelectrolyte films deposited on phospholipid Langmuir-Blodgett films (LB). We were able to change the surface electrical charge density of the LB films by changing the proportions of a negatively charged lipid, the sodium salt of dimyristoyl-sn-glycero-phosphatidyl acid (DMPA), and a zwitterionic lipid. dimyristoyl-sn-glycero-phosphatidylethanolamine (DMPE). This affects the subsequent polyelectrolyte LbL film deposition, which also changes the the nature of the bonding (electrostatic interaction or hydrogen bonding). This approach allowed for the formation of calcium carbonate particles of different final shapes, roughnesses, and sizes. The masses of deposited lipids, polyelectrolytes, and calcium cabonate were quantified by the quartz crystal microbalance technique. The structures of obtained particles were analyzed by scanning electron microscopy.

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Alexandre Oliveira Almeida, Emerson Contreira Mossolin, and Joaldo Rocha Luz (2010) Reproductive biology of the freshwater shrimp Atya scabra (Leach, 1815) (Crustacea: Atyidae) in Ilheus, Bahia, Brazil. Zoological Studies 49(2): 243-252. Reproduction and population aspects of the freshwater shrimp Atya scabra in the Santana River, city of Ilheus, state of Bahia, Brazil, were studied from Apr. 2004 to May 2005. During these 14 mo, 3752 individuals were captured, with a sex ratio of 1.01 males for each female. The total number of individuals caught per month ranged 80-532. Males were generally larger than females. The smallest female found (5.40 mm in carapace length and 29.03 mm in total length) was ovigerous, which indicates that only adult individuals were caught. Ovigerous females were found every month, which indicates continuous reproduction and a high index of reproductive activity during the year. The highest reproduction indices were observed in May (94.3%) and Oct. (98.6%) 2004, and Mar. (93.7%) 2005. Fecundity ranged 870-8907 eggs, with a mean of 3811 (+/- 1992.87) eggs per female. The size of the females and their fecundity were positively correlated. The distribution of individuals in length classes by month showed that representatives of smaller classes occurred throughout almost the entire study period. This indicates a constant input of individuals into the population, which corroborates the characterization of the reproductive period as being continuous, and explains the large numbers of ovigerous females found each month. The 2nd abdominal segment is proportionally larger in females than in males, in width, height, and pleural length: these female secondary characteristics are related to an increased incubation area for eggs. http://zoolstud.sinica.edu.tw/Journals/49.2/243.pdf

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Neuropathic arthropathy (Charcot`s arthropathy) is a progressive articular disease associated with a reduced sensorial and protector proprioceptive reflex. Its etiology includes many different conditions such as syringomyelia, traumatic lesion causing medullary deformity, spina bifida, diabetic neuropathy, leprosy neuropathy, neurofibromatosis, amyloid neuropathy, alcohol, and repetitive injection of hydrocortisone into joints, among others. However, the relationship between Charcot`s arthropathy and herpetic encephalitis has not yet been described. Herpes encephalitis causes acute and chronic diseases of the peripheral or central nervous system. It can manifest as subacute encephalitis, recurrent meningitis, or myelitis. It can also resemble psychiatric syndromes, diplopia, sensory changes in the face and limbs, personality changes, frontal dysexecutive syndrome, stiff neck, subclinical alterations of the vestibular function, intracranial hypertension, convulsion, hemiparesis, and generally includes motor components, among others. On the other hand, pure peripheral sensory disturbance has not been described. In this article, we report the clinical case of a patient with Charcot`s arthropathy secondary to pure peripheral sensory polyneuropathy as a consequence of progressive herpetic encephalitis sequelae. In this article, the authors report the first case of Charcot`s arthropathy secondary to herpetic encephalitis.

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Context: Isolated heterozygous SHOX defects are the most frequent monogenic cause of short stature, and combined therapy with recombinant human GH (rhGH) and GnRH analog (GnRHa) in pubertal patients has been suggested, but there are no data on final height. Objective: The aim of the study was to analyze adult height after rhGH and GnRHa therapy in patients with SHOX haploinsufficiency. Patients: Ten peripubertal patients with isolated SHOX defects participated in the study. Intervention: Five patients were followed without treatment, and five were treated with rhGH (50 mu g/kg/d) and depot leuprolide acetate (3.75 mg/month). Main Outcome Measures: Adult height SD score (SDS) was measured. Results: All patients followed without treatment had marked downward growth shift during puberty (height SDS, -1.2 +/- 0.7 at 11.4 +/- 1.4 yr; adult height SDS, -2.5 +/- 0.5). Conversely, four of five patients treated with rhGH for 2 to 4.9 yr associated to GnRHa for 1.4 to 5.8 yr improved their height SDS from -2.3 +/- 1.3 at 11.8 +/- 2.1 yr to a final height SDS of -1.7 +/- 1.6. The difference between the mean height SDS at the first evaluation and final height SDS was statistically significant in nontreated vs. treated patients (mean height SDS change, -1.2 +/- 0.4 vs. 0.6 +/- 0.4, respectively; P < 0.001). Conclusion: A gain in adult height of patients with isolated SHOX defects treated with combined rhGH and GnRHa therapy was demonstrated for the first time, supporting this treatment for children with SHOX defects who have just started puberty to avoid the loss of growth potential observed in these patients during puberty. (J Clin Endocrinol Metab 95: 328-332, 2010)