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171.
Vasconcelos AF Monteiro NK Dekker RF Barbosa AM Carbonero ER Silveira JL Sassaki GL da Silva R de Lourdes Corradi da Silva M 《Carbohydrate research》2008,343(14):2481-2485
Four exopolysaccharides (EPS) obtained from Botryosphaeria rhodina strains isolated from rotting tropical fruit (graviola, mango, pinha, and orange) grown on sucrose were purified on Sepharose CL-4B. Total acid hydrolysis of each EPS yielded only glucose. Data from methylation analysis and (13)C NMR spectroscopy indicated that the EPS from the graviola isolate consisted of a main chain of glucopyranosyl (1-->3) linkages substituted at O-6 as shown in the putative structure below: [carbohydrate structure: see text]. The EPS of the other fungal isolates consisted of a linear chain of (1-->6)-linked glucopyranosyl residues of the following structure: [carbohydrate structure: see text]. FTIR spectra showed one band at 891 cm(-1), and (13)C NMR spectroscopy showed that all glucosidic linkages were of the beta-configuration. Dye-inclusion studies with Congo Red indicated that each EPS existed in a triple-helix conformational state. beta-(1-->6)-d-Glucans produced as exocellular polysaccharides by fungi are uncommon. 相似文献
172.
Marcussi VM Marcussi LM Barbosa-Tessmann IP Lonardoni MV Silveira TG 《Experimental parasitology》2008,(4):300-305
The objective of this study was to develop specific primers for Leishmania (Viannia) braziliensis species identification using PCR. The designed primers (LBF1 and LBR1) were evaluated for sensitivity and specificity using various L. (V.) braziliensis serodemes and various Leishmania species and also using Trypanosoma cruzi. A specific fragment of 536 bp was detected from 50 ng of DNA in a crude extract derived from L. (V.) braziliensis. The DNA fragment was not detected when DNA from other Leishmania species or from T. cruzi was used as template in the PCR. Furthermore, when tested with DNA from cutaneous leishmaniasis the designed primers and reaction gave positive results. Taking into consideration that the primers LBF1 and LBR1 could specifically identify L. (V.) braziliensis, they could be considered for use in L. (V.) braziliensis diagnosis and epidemiological studies. 相似文献
173.
Appel MH da Silveira RB Chaim OM Paludo KS Silva DT Chaves DM da Silva PH Mangili OC Senff-Ribeiro A Gremski W Nader HB Veiga SS 《Biochimica et biophysica acta》2008,1780(2):167-178
Brown spider bites are associated with lesions including dermonecrosis, gravitational spreading and a massive inflammatory response, along with systemic problems that may include hematological disturbances and renal failure. The mechanisms by which the venom exerts its noxious effects are currently under investigation. It is known that the venom contains a major toxin (dermonecrotic toxin, biochemically a phospholipase D) that can experimentally induce dermonecrosis, inflammatory response, animal mortality and platelet aggregation. Herein, we describe cloning, heterologous expression, purification and functionality of a novel isoform of the 33 kDa dermonecrotic toxin. Circular dichroism analysis evidenced correct folding for the toxin. The recombinant toxin was recognized by whole venom serum antibodies and by a specific antibody to a previously described dermonecrotic toxin. The identified toxin was found to display phospholipase activity and dermonecrotic properties. Additionally, the toxin caused a massive inflammatory response in rabbit skin dermis, evoked platelet aggregation, increased vascular permeability, caused edema and death in mice. These characteristics in combination with functional studies for other dermonecrotic toxins illustrate that a family of dermonecrotic toxins exists, and includes a novel member with high activity that may be useful for future structural and functional studies. 相似文献
174.
de Lourdes Corradi da Silva M Fukuda EK Vasconcelos AF Dekker RF Matias AC Monteiro NK Cardoso MS Barbosa AM Silveira JL Sassaki GL Carbonero ER 《Carbohydrate research》2008,343(4):793-798
Three D-glucans were isolated from the mycelium of the fungus Botryosphaeria rhodina MAMB-05 by sequential extraction with hot-water and hot aqueous KOH (2% w/v) followed by ethanol precipitation. Following their purification by gel permeation chromatography on Sepharose CL-4B, the structural characteristics of the D-glucans were determined by FT-IR and 13C NMR spectroscopy and, after methylation, by GC-MS. The hot-water extract produced a fraction designated Q1A that was a beta-(1-->6)-D-glucan with the following structure: [Formula: see text] The alkaline extract, when subjected to repeated freeze-thawing, yielded two fractions: K1P (insoluble) that comprised a beta-(1-->3)-D-glucan with beta-D-glucose branches at C-6 with the structure: [Formula: see text] and K1SA (soluble) consisting of a backbone chain of alpha-(1-->4)-linked D-glucopyranosyl residues substituted at O-6 with alpha-D-glucopyranosyl residues: [Formula: see text] 相似文献
175.
Vânia Gomes Rosane G. Collevatti Fernando A.O. Silveira G. Wilson Fernandes 《Conservation Genetics》2004,5(2):157-165
Distribution of genetic variability may becorrelated with life history traits, such asreproductive system, pollination, seeddispersal mode, geographical distribution, andlocal abundance. We used RAPD markers to studythe distribution of genetic variability of sixpopulations of Baccharis concinna(Asteraceae), a rare, dioecious and threatenedshrub, endemic to Serra do Cipó,southeastern Brazil, along an altitudinalgradient, ranging from 950 to 1300 m above sealevel. From 113 RAPD markers, 35 wererestricted to one of the six populations.Genetic variability distribution in B.concinna populations was weakly related to thealtitudinal gradient. The largest proportion ofthe genetic variability was due to variationwithin populations (82.82%, P < 0.001), while17.18% (P < 0.001) was due to variation amongpopulations from different elevations.Similarity among populations along thealtitudinal gradient was high, ranging from 65to 74%, suggesting an intensive gene flowamong them or a recent fragmentation of anancient population into many small populations.Dioecy and other life history traits such aswind pollination and seed dispersal mayinfluence the distribution of the geneticvariability in this species. In addition, fireand habitat fragmentation represent otherimportant factors that influence thesurvivorship of this rare and threatenedspecies, and hence the distribution of itsgenetic variability. 相似文献
176.
Vanildo?Silveira Tiago?S.?Balbuena Claudete?Santa-Catarina Eny?I.S.?Floh Miguel?P.?Guerra Walter?HandroEmail author 《Plant Growth Regulation》2004,44(2):147-156
Amino acids, polyamines, 3-indoleacetic acid (IAA), abscisic acid (ABA), buffer-soluble protein and starch contents and dry matter accumulation were analyzed in megagametophytes containing developing embryos during seed development in Pinus taeda. The highest total amino acids and polyamine contents occurred at the cotyledonary stage, followed by a significant decrease in the mature seed. Free polyamines exhibited higher levels than conjugated ones, with putrescine being the predominant type until the cotyledonary stage, and spermidine at the mature seed stage. IAA content increased continually from the globular stage reaching the maximum at the cotyledonary stage, followed by a decrease in the mature seed. The highest ABA level occurred at the globular stage, followed by a continuous reduction until stabilization at the pre-cotyledonary stage. Buffer-soluble protein and starch contents, and dry matter increased progressively during development, reaching their maximum values at the mature stage. 相似文献
177.
178.
Superoxide dismutase, catalase and peroxidase activities do not confer protection against oxidative damage in salt-stressed cowpea leaves 总被引:10,自引:0,他引:10
179.
We herein provide the first observations on planulation, larval development, and metamorphosis of Siderastrea stellata, an endemic reef-building species that occurs along the northeastern and southeastern coasts of Brazil. The release and settlement of larvae were observed in two distinct periods. The first started 3 days after collection on January 28 during the last quarter, whereas the second started 2 months later, on April 10 during the change from new moon to the first quarter. Planulation continued throughout approximately 48 h. Brooded larvae released from the mouth contained zooxanthellae, and underwent settlement after 48 h. Newly extruded larvae stayed in close contact with parental polyps. Fusion was observed among larvae from the same colony. The first septal cycle was formed by day 2–3, while the third cycle of exosepta became evident 15 days after protosepta development. The development of the corallite of primary polyp was slow, and after 9 months of analyses no evidence of budding was obtained, this indicating that colonial development is likely to be a late event in the S. stellata life history. 相似文献
180.
Catia Silene Klein Itamar Antônio Piffer Sérgio Ceroni da Silva Augusto Schrank Maria Bernardete Burin Fávero Irene Silveira Schrank 《Current microbiology》2003,46(6):0443-0447
We investigated whether primers able to specifically amplify a 0.7-kb DNA fragment from the conserved cpx genes could be applied to analyze A. pleuropneumoniae field isolates. The specific cpx primers were tested on 120 strains of A. pleuropneumoniae and other NAD-dependent field isolates from healthy and diseased animals to analyze A. pleuropneumoniae isolates from pigs in Brazil. We found that PCR and hybridization were able to discriminate between isolates of A. pleuropneumoniae and other bacteria. The 0.7-kb cpx DNA fragments were amplified from all 63 A. pleuropneumoniae isolates from herds with clinical symptoms and were isolated from lesions of acute cases of swine pleuropneumonia, both serotypable
and nonserotypable. The PCR was also applied to 57 field isolates obtained from animals of apparently healthy herds, and the
amplified cpx product was present in four serotypable and only two out of eleven A. pleuropneumoniae nonserotypable isolates. All nonserotypable A. pleuropneumoniae isolates revealed the apxA amplification pattern compatible with previously known serotypes. Some nonserotypable isolates might represent a population
of isolates that originally were serotypable but lost the ability to react with serotype-specific antisera or might belong
to novel serotypes. The PCR method applied is highly sensitive for serotypable A. pleuropneumoniae strains and for nonserotypable strains isolated from acute cases of swine pleuropneumoniae in Brazil.
Received: 13 June 2002 / Accepted: 5 August 2002 相似文献