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991.
Different cytogenetic techniques were used to analyse the chromosomes of Prochilodus lineatus with the main objective of comparing the base composition of A- and B-chromosomes. The results of digestion of chromosomes
with 10 different restriction endonucleases (REs), silver staining, CMA3 staining and C-banding indicated the existence of different classes of highly repetitive DNA in the A-set and also suggested
the existence of compositional differences between the chromatin of A- and B-chromosomes. The 5-BrdU incorporation technique
showed a late replicating pattern in all B-chromosomes and in some heterochromatic pericentromeric regions of A-chromosomes.
The cleavage with RE BamHI produced a band pattern in all chromosomes of P. lineatus which permitted the tentative pairing of homologues in the karyotype of this species. We concluded that the combined use
of the above techniques can contribute to the correct identification of chromosomes and the karyotypic analysis in fishes.
On the basis of the results, some aspects of chromosome structure and the origin of the B-chromosomes in P. lineatus are discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
992.
993.
éder Tadeu Gomes Cavalheiro Christopher M. A. Brett Ana Maria Oliveira-Brett Orlando Fatibello-Filho 《Bioanalytical reviews》2012,4(1):31-53
Recent developments in the bioelectroanalysis of pharmaceutical compounds are reviewed, concentrating particularly on the development of electrode materials and measurement strategies and on their application. The advantages of electroanalytical techniques as alternatives to other analytical procedures such as rapid response, sensitivity and low detection limits are highlighted and illustrated. Particular emphasis is given to carbon-based materials for voltammetric electroanalysis; new potentiometric sensors and electrochemical biosensors are also reviewed. 相似文献
994.
Ferreira JL Borborema SE Brígido LF Oliveira MI Paiva TM Santos CL 《Memórias do Instituto Oswaldo Cruz》2011,106(5):613-616
In this paper, we analysed the haemagglutinin (HA) gene identified by polymerase chain reaction from 90 influenza A H1N1 virus strains that circulated in Brazil from April 2009-June 2010. A World Health Organization sequencing protocol allowed us to identify amino acid mutations in the HA protein at positions S220T (71%), D239G/N/S (20%), Y247H (4.5%), E252K (3.3%), M274V (2.2%), Q310H (26.7%) and E391K (12%). A fatal outcome was associated with the D239G mutation (p < 0.0001). Brazilian HA genetic diversity, in comparison to a reference strain from California, highlights the role of influenza virus surveillance for study of viral evolution, in addition to monitoring the spread of the virus worldwide. 相似文献
995.
996.
Cristina de Oliveira Dias 《Hydrobiologia》1996,324(3):253-256
Seven monstrilloid species of the genera Thaumaleus and Monstrilla (Copepoda) are reported from the Brazilian coast. Occurrence, distribution and ecological information is given for: T. longispinosum, T. rigidum, T. quadridens, M. recticulata, M. grandis, M. dubia and M. rugosa. 相似文献
997.
Cell suspensions of Olea europaea var. Galega Vulgar grown in batch culture with 0.5% (w/v) glucose were able to transport D-[(14)C]glucose according to Michaelis-Menten kinetics associated with a first-order kinetics. The monosaccharide carrier exhibited high affinity (K(m) approximately 50 micro M) and was able to transport D-glucose, D-fructose, D-galactose, D-xylose, 2-deoxy-D-glucose and 3-O-methyl-D-glucose, but not D-arabinose, D-mannitol or L-glucose. D-[(14)C]glucose uptake was associated with proton uptake, which also followed Michaelis-Menten kinetics. The transport of 3-O-methyl-D-glucose was accumulative (40-fold, at pH 5.0) and the protonophore carbonyl cyanide m-chlorophenylhydrazone strongly inhibited sugar accumulation. The results were consistent with the involvement of a monosaccharide: proton symporter with a stoichiometry of 1 : 1. When cells were grown with 3% (w/v) glucose, the uptake of D-[(14)C]glucose followed first-order kinetics and monosaccharide:proton symporter activity was not detected. The value obtained for the permeability coefficient of hexoses in O. europaea cells supported the hypothesis that the first-order kinetics observed in 0.5% and 3% sugar-grown cells was produced exclusively by passive diffusion of the sugar. The results indicate that in O. europaea cells sugar levels have a regulatory effect on sugar transport, because the activity for monosaccharide transport was repressed by high sugar concentrations. 相似文献
998.
Aceric acid (3-C-carboxy-5-deoxy-alpha-l-xylofuranose) residues are present in pectic polysaccharide rhamnogalacturonan II (RG II) in the form of synthetically challenging 1,2-cis-glycofuranosides. To access synthetic fragments of RG II incorporating aceric acid, a four-step procedure based on C-2 epimerisation of initially prepared 1,2-trans-glycofuranoside was developed. Readily available derivatives of branched-chain l-lyxofuranose bearing a 3-C-vinyl group as a masked 3-C-carboxyl group were investigated as potential precursors of aceric acid units. In the first step of the procedure, installation of a participating group at C-2 of the furanose ring ensured stereocontrol of the O-glycosylation, which was carried out with the thioglycoside of 2-O-acetyl-3,5-di-O-benzyl-3-C-vinyl-L-lyxofuranose. After the glycosylation step, the 2-O-acetyl group was removed, the free 2-OH group was oxidised and the resulting ketone was finally reduced to form the C-3-vinyl-L-xylofuranoside. The use of L-Selectride in the key reduction reaction was essential to achieve the required stereoselectivity to generate 1,2-cis-furanoside. 相似文献
999.
Ferreira Matheus M. de Oliveira Gustavo F. Basso Rodrigo C. Mendes Adriano A. Hirata Daniela B. 《Bioprocess and biosystems engineering》2019,42(10):1647-1659
Bioprocess and Biosystems Engineering - This study aimed to optimize free fatty acid production by enzymatic hydrolysis of cottonseed, olive and palm kernel oils in stirred-tank reactors using a... 相似文献
1000.