961 resultados para xylan 1,4 beta xylosidase
Resumo:
The esterase patterns of sixteen strains from four species in the saltans subgroup were analyzed using polyacrylamide gel electrophoresis. Thirty-four esterase bands were detected. By using alpha and beta naphthyl acetates as substrates, they were classified in 18 alpha-esterases (they hydrolyse the alpha-naphtyl substrate), 15 beta-esterases (they hydrolyse the beta-naphtyl substrate) and 1 alpha/beta-esterase (it hydrolyses the alpha and beta-naphtyl substrates). Among the alpha-esterases, three were detected exclusively in males. Malathion, Eserine and pCMB were used as inhibitors in order to characterize biochemically the esterases. The results indicated the presence of cholinesterases, carboxylesterases and acetylesterases. The degree of mobility of the bands in the gels, their specificity to alpha and beta naphthyl acetates and the results of the inhibition tests allowed us to recognize tentatively nine genetic loci. Phylogenetic relationships among species inferred on the basis of the esterase patterns by PAUP 4.0 b8, with neighbor-joining search and a bootstrap analysis showed that, although the four species are closely related, D. septentriosaltans, D. saltans and D. austrosaltans are closer to each other than to D. prosaltans. These results showed to be consistent with phylogenetic relationships previously inferred from inversion polymorphism.
Resumo:
Phenylpropanoid glycosides, 1 '-O-benzyl-alpha-(L)-rhamnopyranosyl-(1 ''-> 6 ')-beta-(D)-glucopyranoside (1) and alpha-(L)-Xylopyranosyl(4 '', 2 ')-(3-O-beta-(D)-glucopyranosyl)-1 '-O-E-caffeoyl-beta-(D)-glucopyranoside (2), together with the known derivatives, 1,6-di-O-caffeoyl- beta-(D)-glucopyrano side (3), 1-O-(E)-caffeoyl-beta-(D)-glucopyranoside (4) and 1-O-(E)-feruloyl-beta-(D)-glucopyranoside (5), were isolated from leaves of Coussarea hydrangeifolia. Their structures were determined by IR, HRESIMS, and I D and 2D NMR experiments, and their antioxidant activities, evaluated by assaying the free radical scavenging capacity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical as substrate. The antioxidant activities of 3 and 4 (IC50 values of 15.0 and 19.2 mu M, respectively) were comparable to that of the standard positive control caffeic acid, whilst 2 and 5 were only weakly active and 1 was inactive. (c) 2005 Elsevier Ltd. All rights reserved.
Resumo:
A rapid, sensitive and reliable reverse-phase HPLC method was used for the quantitative determination of the anti-fungal and insecticide amides, dihydropiplartine (1), piplartine (2), Delta(alpha,beta)-dihydropiperine (3) and pellitorine (4) in plants in natura, in plantlets in vitro and ex vitro, and in callus of Piper tuberculatum. Well-resolved peaks were obtained with good detection response and linearity in the range of 15.0-3000 mug/mL. The plants in natura contained compounds 1-4, the plantlets ex vitro and in vitro accumulated compounds 1-2 and 1-4, respectively, while only amide 4 was found in callus. Copyright (C) 2003 John Wiley Sons, Ltd.
Resumo:
The oldest fragment of continental crust recognized in South America occurs as an isolated Archean enclave in northeastem Brazil's Borborema Province, ca. 600 Ma Brasiliano-Pan African orogenic belt. This Archean fragment, the Sao Jose do Campestre massif, is surrounded by large tracts of 2.2-2.0 Ga Paleoproterozoic gneisses and is located more than 600-1500 km from the much larger assemblages of Archean rocks found in the Sao Fransciso and Amazonian cratons, located to the south and west, respectively. Geochronological studies of the Sao Jose do Campestre massif show that its oldest rocks contain zircons with U-Pb ages up to 3.5 Ga and Sm-Nd T-DM model ages of more than 3.7 Ga, indicating that they represent reworked crust. This older nucleus is flanked by both reworked and juvenile 3.25 and 3.18 Ga rocks which arc intruded by both 3.00 and 2.69 Ga plutonic bodies. The protracted evolution the Sao Jose do Campestre massif is consistent with that of a larger continental mass as opposed to a small crustal fragment that grew in isolation. As such, the Sao Jose do Campestre massif is interpreted as representing a detached piece of an evolved craton that became entrained with younger rocks during a subsequent Paleoproterozoic accretionary-orogenic event. This hypothesis is bolstered by the presence of Paleoproterozoic gneisses that envelop the Sao Jose do Campestre massif, as well as the existence of ca. 2.0 Ga metamorphic zircon and monazite within its rocks. The occurrence of several different Archean cratonic basement inliers within the greater Paleoproterozoic crustal framework of the Borborema Province suggests that cratonic slices spalled off one or more larger Archean masses prior to the ca. 2.2-2.0 Ga Paleoproterozoic orogenic collage. A important challenge is to link these older fragments to their parent cratons. Although results are not unique, the pattern of ages and isotopic signatures observed in the Sao Jose do Campestre massif is similar to that seen in parts of the Sao Francisco Craton, and it is possible that the Sao Jose do Campestre massif is a fragment of an Archean continental fragment formed during an episode of continental breakup prior to 2200 Ma. (C) 2003 Elsevier B.V. All rights reserved.
Resumo:
This study reports on the effects of growth temperature on the secretion and some properties of the xylanase and beta-xylosidase activities produced by a thermotolerant Aspergillus phoenicis. Marked differences were observed when the organism was grown on xylan-supplemented medium at 25 degreesC or 42 degreesC. Production of xylanolytic enzymes reached maximum levels after 72 h of growth at 42 degreesC; and levels were three- to five-fold higher than at 25 degreesC. Secretion of xylanase and beta-xylosidase was also strongly stimulated at the higher temperature. The optimal temperature was 85 degreesC for extracellular and 90 degreesC for intracellular beta-xylosidase activity, independent of the growth temperature. The optimum temperature for extracellular xylanase increased from 50 degreesC to 55 degreesC when the fungus was cultivated at 42 degreesC. At the higher temperature, the xylanolytic enzymes produced by A. phoenicis showed increased thermo stability, with changes in the profiles of pH optima. The chromatographic profiles were distinct when samples obtained from cultures grown at different temperatures were eluted from DEAE-cellulose and Biogel P-60 columns.
Resumo:
C20H34, monoclinic, P12(1)/n1 (no. 14), a = 10.647(l) angstrom, b = 6.6844(9) angstrom, c = 11.723(1) angstrom, beta = 99.75(1)degrees, V = 822.3 angstrom(3) Z = 2, R-gt(F) = 0.043, wR(ref)(F-2) = 0.110, T = 93 K.
Resumo:
3,4,4'-trichlorocarbanilide (TCC) was rested as a new method of bacterial growth control for S. cerevisiae alcoholic fermentations of diluted high test molasses (HTM). Minimal inhibitory concentration (MIC) was tested to determine the necessary concentration of TCC to control bacterial growth. The fed-batch alcoholic fermentation process was used with cell recycle similar to industrial conditions and Lactobacillus fermentum CCT 1407 was mixed in the first inoculum to grow with the yeast. Yeast extract was added into the must to stimulate bacterial growth. The best results of TCC's MIC to bacterial growth of Lactobacillus fermentum and Leuconostoc mesenteroides (< 0.125-1.0 mu g/ml) and Saccharomyces cerevisiae (16 mu g/ml) occurred when it was combined with sodium dodecylsulphate (SDS) in a 1: 4 TCC/SDS ratio (wt/wt) in distilled water solution. 1.8 g/l TCC entrapped in calcium alginate added to the must with yeast extract inhibited the growth of Lactobacillus fermentum CCT 1407 maintaining a controlled acidity, higher yeast viability and up to 20.8% of improvement in the average of alcoholic efficiency. Addition of 0.075 g/l TCC entrapped in calcium alginate and 1.67 mg/l SDS in the wort with yeast extract (0-5.0 g/l), inhibited and controlled the extensive bacterial contamination for 19 cycles of fermentation. (C) 1998 Published by Elsevier B.V. Ltd.
Resumo:
The isolation of three new triterpene saponins 3beta-O-beta-D-glucopyranosyl-(1-->3)-alpha-L-2-O-acetylara-binopyranosylolean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (2), 3beta-O-beta-D-glucopyranosyl-(1-->2)-alpha-L-O-arabinopyranosylurs-12-en-28-oic acid (3), and 3beta-O-beta-D-glucopyranosyl-(1-->2)-beta-D-O-galactopyranosylurs-12-en-28-oic acid (4) together with five known saponins and one flavonoid glycoside from the aqueous infusion of flex amara (Vellozo) Loes. leaves is reported. All structures were elucidated by spectroscopic methods, including the concerted application of one-dimensional (H-1, TOCSY, C-13, and C-13 DEPT NMR) and two-dimensional NMR techniques (DQF-COSY, HSQC, and HMBC).
Resumo:
The coumarin antibiotics are potent inhibitors of DNA replication whose target is the enzyme DNA gyrase, an ATP-dependent bacterial type II topoisomerase. The coumarin drugs inhibit gyrase action by competitive binding to the ATP-binding site of DNA gyrase B protein. The production of new biologically active products has stimulated additional studies on coumarin-gyrase interactions. In this regard, a 4.2 kDa peptide mimic of DNA gyrase B protein from Escherichia coli has been designed and synthesized. The peptide sequence includes the natural fragment 131-146 (coumarin resistance-determining region) and a segment containing the gyrase-DNA interaction region (positions 753-770). The peptide mimic binds to novobiocin (K-a = 1.4 +/- 0.3 x 10(5) m(-1)), plasmid (K-a = 1.6 +/- 0.5 x 10(6) m(-1)) and ATP (K-a = 1.9 f 0.4 x 10(3) m(-1)), results previously found with the intact B protein. on the other hand, the binding to novobiocin was reduced when a mutation of Arg-136 to Leu-136 was introduced, a change previously found in the DNA gyrase B protein from several coumarin-resistant clinical isolates of Escherichia coLi. In contrast, the binding to plasmid and to ATP was not altered. These results suggest that synthetic peptides designed in a similar way to that described here could be used as mimics of DNA gyrase in studies which seek a better understanding of the ATP, as well as coumarin, binding to the gyrase and also the mechanism of action of this class of antibacterial drugs. Copyright (C) 2004 European Peptide Society and John Wiley Sons, Ltd.
Resumo:
The mandibular glands of Pachycondyla striata workers consists of a proximal reservoir and secretory portion. The secretion is transported from the cytoplasm of the secretory cells to reservoir through individual canaliculi which is subdivided into two portions : an intracytoplasmatic and extracellular one. The reservoir consists of an epithelium made up of thin cells has a thick cuticle. The secretory cells showed a large amount of structures forming the citoskeleton always associated with myelin figures.
Resumo:
A method for the isolation of three compounds from the infusion of leaves of Byrsonima basiloba A. Juss. by high-speed counter-current chromatography (HSCCC) was developed. This technique led to the separation of a novel compound, quercetin 3-O-alpha-L-rhamnopyranosyl-(1 -> 3)-O-[alpha-L-rhamnopyranosyl-(1 -> 6)]-beta-D-allopyranoside, and two known compounds quercetin3-O-(X-L-rhamnopyranosyl-(1 -> 6)-beta-D-galactopyranoside and (+)-catechin in 4 h with purities of over 92%. The structures of the compounds were determined by one- and two-dimensional NMR spectroscopy and HPLC.
Resumo:
Objective-To evaluate the effects of extracorporeal shock wave therapy (ESWT) on affected ligaments in the hind limbs of horses with experimentally induced suspensory ligament desmitis by use of ultrasonographic, ultrastructural, and immunocytochemical techniques.Animals-10 horses.Procedure-Suspensory ligament desmitis was induced in both hind limbs of each horse by use of 2 collagenase injections (administered 2 weeks apart) in each suspensory ligament. Two weeks after the second injection, the right hind limb of each horse was treated with ESWT (3 treatments at 3-week intervals)- the left hind limb was not treated (control limb). Periodically during the study, the healing process was monitored ultrasonographically and the proportions of ligaments affected with lesions were assessed. Four weeks after the last ESWT treatment, biopsy specimens were collected from all ligaments for ultrastructural evaluation and immunocytochemical analysis of transforming growth factor beta-1.Results-The difference in the proportion of the lesion-affected ligament between ESWT-treated and control limbs was significant (P < 0.05) from 3 weeks after the second ESWT treatment to the end of the study. Compared with control ligaments, ESWT-treated ligaments had more small, newly formed collagen fibrils and greater expression of transforming growth factor beta-1 4 weeks after the last ESWT treatment was administered.Conclusions and Clinical Relevance-Results have indicated that ESWT appears to facilitate the healing process in horses with experimentally induced hind limb suspensory ligament desmitis.
Resumo:
The present experiments were conducted to investigate the role of the alpha (1A)-, alpha (1B), beta (1),- and beta (2)-adrenoceptors of the lateral hypothalamus (LH) on the water and salt intake responses elicited by subfornical organ (SFO) injection of angiotensin II (ANG II) in rats. 5-methylurapidil (an alpha (1A)-adrenergic antagonist), cyclazosin (an alpha (1B)-adrenergic antagonist) and ICI-118,551 (a beta (2)-adrenergic antagonist) injected into the LH produced a dose-dependent reduction, whereas efaroxan (an alpha (2)-antagonist) increased the water intake induced by administration of ANG II into the SFO. These data show that injection of 5-methylurapidil into the LH prior to ANG II into the SFO increased the water and sodium intake induced by the injection of ANG II. The present data also show that atenolol (a beta (1)-adrenergic antagonist), ICI-118,551, cyclazosin, or efaroxan injected into the LH reduced in a dose-dependent manner the water and sodium intake to angiotensinergic activation of SFO. Thus, the alpha (1)- and beta -adrenoceptors of the LH are possibly involved with central mechanisms dependent on ANG II and SFO that control water and sodium intake. (C) 2000 Elsevier B.V. B.V. All rights reserved.
Resumo:
Three new naphthopyranone glycosides, paepalantine-9-O-beta -D-glucopyranosyl-(1 -->6)-beta -D-glucopyranoside (I), paepalantine-9-O-alpha -L-arabinopyranosyl-(1 -->6)-beta -D-glucopyranoside (2), and paepalantinc-9-O-alpha -L-rhamnopyranosyl-( (1 -->6)-beta -D-glucopyranoside (3), along with the known paepalantine-9-O-beta -D-glucopyranoside (4) were isolated from aerial parts of Paepalanthus microphyllus. These compounds were characterized by spectrometric methods, including electrospray mass spectrometry and 1D and 2D NMR experiments. As a part of our program for screening natural compounds for anti-HIV activity, compounds 1-4 were tested in C8166 cells infected with HIV 1(MN).