RESUMO
Determination of the molecular weight of three types of chitosan was carried out by HPSEC-RI. The effect of low, medium and high molecular weight chitosan was evaluated on development of three isolates of Rhizopus stolonifer. Image analysis and electronic microscopy observations were done in spores of this fungus. Germination of R. stolonifer in potato dextrose broth with chitosan was also evaluated. Results pointed out that the low molecular weight chitosan was more effective for inhibition of mycelial growth while the high molecular weight chitosan affected spore shape, sporulation and germination. Studies of scanning and transmission electron microscopy revealed numerous and deeper ridge ornamentations of the chitosan-treated spore.
RESUMO
Though differing only slightly in their degrees of sulfation, heparin preparations from pig mucosa and those from beef mucosa have consistently different 13C- and 1H-NMR spectra, which provide useful fingerprints for distinguishing the two types of heparin. Integrated areas of NMR signals associated with minor, undersulfated sequences (assigned by comparison with mono-dimensional spectra of selectively desulfated heparins and by analysis of two-dimensional spectra of heparins prepared from pig and beef mucosa) permit quantitation of differences in sulfation patterns. Undersulfation of pig mucosal heparins at position 6 of the hexosamine units, determined by 13C-NMR and expressed as percent glucosamines nonsulfated at C6 referred to total glucosamines, is substantially lower for pig mucosal heparins than for beef mucosal heparins (16.9-21.7% vs 36.7-40.7%; average values: 18.6% vs 40.3%). By contrast, undersulfation at position 2 of the iduronic acid units, determined by 1H-NMR and expressed as percent nonsulfated iduronic acid referred to total (sulfated + nonsulfated) iduronic acid is significantly higher for pig mucosal preparations (9.6-13.5% vs 2.1-2.7%; average values: 12.7% vs 2.3%). Pig mucosal heparins also have a significantly higher content of 3-O-sulfated glucosamine units, which are markers for the active site of heparin for antithrombin-III.
Assuntos
Heparina/química , Mucosa Intestinal/química , Sulfatos/química , Animais , Sequência de Carboidratos , Bovinos , Glucosamina/química , Glucosamina/metabolismo , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Especificidade da Espécie , SuínosAssuntos
Gorduras na Dieta , Contaminação de Alimentos , Hiperglicemia/induzido quimicamente , Óleos de Plantas , Brassica , Estudos de Coortes , Diabetes Mellitus Tipo 1/induzido quimicamente , Diabetes Mellitus Tipo 1/epidemiologia , Diabetes Mellitus Tipo 2/induzido quimicamente , Diabetes Mellitus Tipo 2/epidemiologia , Ácidos Graxos Monoinsaturados , Teste de Tolerância a Glucose , Humanos , Hiperglicemia/epidemiologia , Pâncreas/patologia , Prevalência , Óleo de Brassica napus , EspanhaRESUMO
A reversed-phase high-performance liquid-chromatographic method for the determination of caffeine and theophylline in commercial guarana samples (drug obtained from the seeds of Paulinia cupana Kunth, Sapindaceae of the Amazon Region) and in Cola spp. samples is described and discussed. The methodology developed is simple and rapid with a minimum of samples preparation required. A comparison of five different techniques for the extraction of caffeine and theophylline is discussed. Furthermore the quantitative determination of caffeine and theophylline in five samples of Brasilian guarana, in two samples of dietetic products containing guarana, in two samples of Cola extract and in three of Cola seed powder are reported.
