29 resultados para Exploitation of natural flora


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We studied the natural infection of Lutzomyia (Lutzomyia) sp. with Leishmania in endemic foci of cutaneous leishmaniasis in the Paria peninsula, state of Sucre, Venezuela. Sand flies were collected between March 2001 and June 2003, using Shannon light-traps and human bait. Of the 1291 insects captured, only two species of phlebotomines were identified: L. ovallesi (82.75%) and L. gomezi (17.42%). A sample of the collected sand flies (51 pools of 2-12 individuals) were analyzed by using a multiplex-PCR assay for simultaneous detection of New Word Leishmaniaand Viannia subgenera. The results showed a total of 8 pools (15.68%) infected; of these, 7 were L. ovallesi naturally infected with L. braziliensis (2 pools) and L. mexicana (5 pools) and 1 pool of L. gomezi infected by L. braziliensis.

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The avian eye trematode Philophthalmus lachrymosus Braun, 1902 is for the first time referred naturally occurring in a non-human mammalian host. Previously, natural infections with P. lachrymosus and other species of Philophthalmus have been occasionally reported from man, with few data on experimental infections of non-human mammals. Results presented here are related to the report of two cases of philophthalmosis due to natural infections of wild Brazilian capybaras, Hydrochaeris hydrochaeris L., 1766 with P. lachrymosus and associated pathology. Clinical signs, gross and microscopic lesions as well as new morphometric data on the parasite are presented.

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Here we present the first in a series of articles about the ecology of immature stages of anophelines in the Brazilian Yanomami area. We propose a new larval habitat classification and a new larval sampling methodology. We also report some preliminary results illustrating the applicability of the methodology based on data collected in the Brazilian Amazon rainforest in a longitudinal study of two remote Yanomami communities, Parafuri and Toototobi. In these areas, we mapped and classified 112 natural breeding habitats located in low-order river systems based on their association with river flood pulses, seasonality and exposure to sun. Our classification rendered seven types of larval habitats: lakes associated with the river, which are subdivided into oxbow lakes and nonoxbow lakes, flooded areas associated with the river, flooded areas not associated with the river, rainfall pools, small forest streams, medium forest streams and rivers. The methodology for larval sampling was based on the accurate quantification of the effective breeding area, taking into account the area of the perimeter and subtypes of microenvironments present per larval habitat type using a laser range finder and a small portable inflatable boat. The new classification and new sampling methodology proposed herein may be useful in vector control programs.

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Fungi of the genus Paracoccidioides are responsible for paracoccidioidomycosis. The occurrence of drug toxicity and relapse in this disease justify the development of new antifungal agents. Compounds extracted from fungal extract have showing antifungal activity. Extracts of 78 fungi isolated from rocks of the Atacama Desert were tested in a microdilution assay against Paracoccidioides brasiliensis Pb18. Approximately 18% (5) of the extracts showed minimum inhibitory concentration (MIC) values≤ 125.0 µg/mL. Among these, extract from the fungus UFMGCB 8030 demonstrated the best results, with an MIC of 15.6 µg/mL. This isolate was identified as Aspergillus felis (by macro and micromorphologies, and internal transcribed spacer, β-tubulin, and ribosomal polymerase II gene analyses) and was grown in five different culture media and extracted with various solvents to optimise its antifungal activity. Potato dextrose agar culture and dichloromethane extraction resulted in an MIC of 1.9 µg/mL against P. brasiliensis and did not show cytotoxicity at the concentrations tested in normal mammalian cell (Vero). This extract was subjected to bioassay-guided fractionation using analytical C18RP-high-performance liquid chromatography (HPLC) and an antifungal assay using P. brasiliensis. Analysis of the active fractions by HPLC-high resolution mass spectrometry allowed us to identify the antifungal agents present in the A. felis extracts cytochalasins. These results reveal the potential of A. felis as a producer of bioactive compounds with antifungal activity.

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Carotenoids are natural dyes synthesized by plants, algae and microorganisms. Application in many sectors can be found, as food dyeing and supplementation, pharmaceuticals, cosmetics and animal feed. Recent investigations have shown their ability to reduce the risks for many degenerative diseases like cancer, heart diseases, cataract and macular degeneration. An advantage of microbial carotenoids is the fact that the cultivation in controlled conditions is not dependent of climate, season or soil composition. In this review the advances in bio-production of carotenoids are presented, discussing the main factors that influence the microbial production of these dyes in different systems.

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In this paper, we carry out a study on the process of sorption of lead in polluted waters usingnatural zeolites, with the objective of analyzing their behavior in the purification of water.Experiments are carried out under static and dynamic conditions to determine the influence of other metal ions, such as: Ca (II), Mg (II), K (I) and Na (I), on this process. We demonstrate that the affinity of Pb (II) with regard to zeolite is higher than that of the ions mentioned above. It allows us to use this material in the capture of lead in residual waters. A lineal model of regression was obtained using a computer program called Eureka which relates the capacity of interchange of zeolite with respect to the concentration of the metal ions present in waters. We also studied the selectivity of zeolite in the process of sorption of Pb (II) compared with other heavy metals like Zn (II) and Cd (II).The results achieved in both cases increase the expectancy about the usage of zeolite as a low cost material for purifing waters.

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ABSTRACT2-Phenylethanol (PE) is an aromatic alcohol with a characteristic odor of roses, widely used in food industry to modify certain aroma compositions in formulations with fruit, jam, pudding, and chewing gums, and also in cosmetic and fragrance industry. This compound occurs naturally in low concentrations in some essential oils from flowers and plants. An alternative to plants extraction are biotechnological processes. This study evaluated 2-phenylethanol’s production in cultivation of Saccharomyces cerevisiae in cassava wastewater originated from starch industry. The substrate was supplemented with glucose and L-phenylalanine in order to obtain higher 2-phenylethanol concentrations and better efficiency in glucose/2-phenylethanol conversion. It was performed using Rotatable Center Composite Design and response surface analysis. Cultures were performed under aerobic conditions in a batch system in Erlenmeyer flasks containing 50 mL of medium in shaker at 150 rpm and 24 ± 1 ºC. The highest PE values ​​were obtained with supplementation of 20.0 g.L-1 of glucose and 5.5 g.L-1 of L-phenylalanine, which has been experimentally validated, obtaining a PE production of 1.33 g.L-1 and PE/glucose yield factor of 0.070 g.g-1, equivalent to 74.3 and 89.7% ​​of desirability values according to the validated model.

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Objective: to evaluate natural evolution of right diaphragmatic injury after the surgical removal of a portion from hemi diaphragm. Methods: the animals were submitted to a surgical removal of portion from right hemi diaphragm by median laparotomy. The sample consists of 42 animals being 2 animals from pilot project and 40 operated animals. And the variables of the study were herniation, liver protection, healing, persistent diaphragm injury, evaluation of 16 channels tomography and the variables "heart rate" and "weight". Results: we analyzed 40 mice, we had two post-operative deaths; we had 17 animals in this group suffered from herniation (42.5%) and 23 animals didn't suffer from herniation (57.5%). Analyzing the tomography as image method in the evaluation of diaphragmatic hernia, we had as a method with good sensitivity (78.6%), good specificity (90.9%), and good accuracy (86.1%) when compared to necropsy. Conclusion: there was a predominance of healing of right hemi diaphragm, the size of initial injury didn't have influence on occurrence of the liver protection or hernia in mice.

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The Brazilian Spotted Fever (BSF) is a zoonotic disease caused by Rickettsia rickettsii and transmitted by ticks of the genus Amblyomma, more frequently, Amblyomma cajennense. The aim of this paper was to report the first molecular detection of R. rickettsii on R. sanguineus naturally infected in Rio de Janeiro, Brazil. Ticks were collected from dogs in a rural region of Resende municipality, Rio de Janeiro State, Brazil (22º30'9.46"S, 44º42'44.29"WO), where occurred five human cases of BSF in 2006. The ticks were identified under a stereoscopic microscope and separated in pools by stages, species and sex. DNA extraction was carried out using QIAamp DNA Mini Kit (QIAGEN®). The DNA was submitted to PCR amplification using 04 set of primers: Rr190.70p/Rr190.602n (OmpA, 532bp), BG1-21/BG2-20 (OmpB, 650bp), Tz15/Tz16 (17 kDa protein-encoding gene, 246bp) and RpCS.877p/RpCS.1258n (gltA, 381bp). PCR products were separated by electrophoresis on 1% agarose gels and visualized under ultraviolet light with ethidium bromide. PCR products of the expected sizes were purified by QIAquick® and sequenced by ABI PRISM®. The generated nucleotide sequences were edited with using Bioedit® software and compared with the corresponding homologous sequences available through GenBank, using Discontiguous Mega Blast (http://www.ncbi.nlm.nih.gov). It was confirmed R. rickettsii by sequencing of the material (GenBank FJ356230). The molecular characterization of R. rickettsii in the tick R. sanguineus emphasizes the role of dogs as carriers of ticks from the environment to home. Moreover, this result suggests that there is a considerable chance for active participation of R. sanguineus as one of tick species in the transmission of R. ricketsii to human being in the Brazilian territory.

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Hybridization between B. involutum and B. weddellii (Orchidaceae) has been first observed in the Serra do Cipó, Minas Gerais State, Brazil, the hybrid being described as B. ×cipoense Borba & Semir. In this study, allozime electrophoresis was used to test the hypothesis of occurrence of hybridization between these two species, as suggested by morphological characters, in the Chapada Diamantina, Bahia State, Brazil. The lack of a diagnostic locus does not allow definite confirmation of the natural hybridization, although this hypotheses is reinforced by the absence of exclusive alleles in the putative hybrid individuals. The existence of several different genotypes points out to either population derived from multiple hybridization events or the hybrids produced offspring. Homozigosity in some morphologically intermediate individuals of alelles which are exclusive to B. involutum and high genetic similarity between them reinforce the hypotheses of introgression in B. involutum, but not in B. weddellii. Genetic variability observed in B. weddellii (He = 0.21) and B. involutum (He = 0.35) is high. Bulbophyllum weddellii and B. involutum presented very high genetic similarity values (0.94). These species, although vegetatively similar, have been placed in different sections based on floral morphology. The results suggest that these species may be more related than previously supposed.

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An area's innate potential to regenerate represents a crucial factor for its conservation and management. The seed rain and seed bank are important agents in the regeneration process. Seed banks are particularly important in communities where there is a high proportion of obligate seeders. Rocky outcrops are habitats where most part of the plant species depends on their seeds to reproduce and maintain viable populations. Therefore, seed banks ought to be important in this vegetation physiognomy. We test the hypotheses that the seed bank of the rocky outcrops found in the rupestrian fields of "Serra do Cipó", Brazil, is richer in species and denser than those formed on different vegetation physiognomies neighboring the outcrops. We then compared species abundance, species richness and composition in the rocky outcrops' seed banks with those of sandy and peaty bogs, forests, gallery forests, and "cerrados". Furthermore, we report on the natural regeneration potential of these soils by assessing a greenhouse study on seedling emergence. Soil samples were collected from 0 to 5 and 5 to 10 cm of depth. Rocky outcrops had the poorest in species and less dense seed bank and showed segregation in species composition. Emergence was greater in the most superficial layer. However, soils on rocky outcrops showed the greatest proportion of endemic threatened species in their seed banks, demonstrating their importance for biodiversity conservation of the "Serra do Cipó" rupestrian fields.

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In order to study the role of natural killer (NK) cells during the early period of Leishmania infection, BALB/c mice were selectively and permanently depleted of NK cells by injection with 90Sr and subsequently infected with Leishmania (Leishmania) amazonensis (HSJD-1 strain). 90Sr is known to selectively deplete NK cells, leaving an intact T- and B-cell compartment and preserving the ability to produce both interferon alpha and IL-2. This method of depletion has advantages when compared with depletion using anti-NK cell monoclonal antibodies because the effect is permanent and neither activates complement nor provokes massive cell death. In the present study, after one month of treatment with 90Sr, the depletion of NK cells was shown by a more than ten-fold reduction in the cytotoxic activity of these cells: 2 x 106 spleen cells from NK-depleted animals were required to reach the same specific lysis of target cells effected by 0.15 x 106 spleen cells from normal control animals. The histopathology of the skin lesion at 7 days after Leishmania infection showed more parasites in the NK cell-depleted group. This observation further strengthens a direct role of NK cells during the early period of Leishmania infection.

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There is evidence concerning the participation of reactive oxygen species in the etiology and physiopathology of human diseases, such as neurodegenerative disorders, inflammation, viral infections, autoimmune pathologies, and digestive system disorders such as gastrointestinal inflammation and gastric ulcer. The role of these reactive oxygen species in several diseases and the potential antioxidant protective effect of natural compounds on affected tissues are topics of high current interest. To consider a natural compound or a drug as an antioxidant substance it is necessary to investigate its antioxidant properties in vitro and then to evaluate its antioxidant functions in biological systems. In this review article, we shall consider the role of natural antioxidants derived from popular plants to reduce or prevent the oxidative stress in gastric ulcer induced by ethanol.

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Penicillium expansum is the causative agent of apple blue mold. The inhibitory effects of the capsaicin derived from Capsicum spp. fruits and yeast Hansenula wingei against P. expansum were evaluated in an in vitro and in in vivo assay using Fuji apples. The minimum inhibitory concentration of capsaicin determined using the broth micro-dilution method was 122.16 µg mL-1. Capsaicin did not reduce blue mold incidence in apples. However, it was able to delay fungal growth in the first 14 days of the in vivo assay. The in vivo effect of the yeast Hansenula wingei AM2(-2), alone and combined with thiabendazole at low dosage (40 µg mL-1), on the incidence of apple diseases caused by P. expansum was also described. H. wingei AM2(-2) combined with a low fungicide dosage (10% of the dosage recommended by the manufacturer) showed the best efficacy (100%) up to 7 days of storage at 21 ºC, later showing a non-statistically different decrease (p > 0.05) after 14 (80.45%) and 21 days (72.13%), respectively. These results contribute providing new options for using antifungal agents against Penicillium expansum.