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1.
J Toxicol Sci ; 35(4): 493-501, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20686336

RESUMEN

This study was designed to evaluate and characterize any subchronic toxicity of rhamsan gum, a polysaccharide produced from Sphingomonas strain ATCC 31961, when administered to both sexes of Crl:CD(SD)IGS rats at dietary levels of 0 (control), 0.5, 1.5, and 5.0% (10 rats/sex/group). During the study, the treatment had no adverse effects on clinical signs, survival, body weights and food and water consumption, or on findings of urinalysis, ophthalmology, hematology, or blood biochemistry. Examination of gross pathology and histopathology exhibited no differences of toxicological significance between control and treated rats. Increased relative cecum (filled) and cecum (empty) weights, evident in males of 1.5% group and both sexes of the 5.0% group, were considered to be a physiological adaptation. Thus, the results indicated the toxic level of rhamsan gum to be more than 5.0%, and the no-observed-adverse-effect level (NOAEL) was concluded to be 5.0% (3,362 mg/kg body weights/day for males, and 4,304 mg/kg body weights/day for males) from the present study.


Asunto(s)
Polisacáridos Bacterianos/toxicidad , Administración Oral , Animales , Peso Corporal/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ingestión de Líquidos/efectos de los fármacos , Femenino , Masculino , Nivel sin Efectos Adversos Observados , Polisacáridos Bacterianos/administración & dosificación , Ratas , Ratas Sprague-Dawley , Sphingomonas/metabolismo , Urinálisis
2.
J Toxicol Sci ; 35(3): 317-25, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20519840

RESUMEN

This study was designed to evaluate any adverse effect of fermentation-derived cellulose, produced by Acetobacter aceti subspecies xylinum, when administered to both sexes of F344 rats at dietary levels of 0, 1.25, 2.5, and 5.0% for 28 days. The treatment had no adverse effects on clinical signs, mortality, body weights and food and water consumption, or on urinalysis, ophthalmology, hematology, blood biochemistry, and histopathology findings. At necropsy, slight increased absolute and relative cecum weights, evident in females ingesting 2.5% and 5.0% dietary levels, were considered to be a physiological adaptation to the poorly absorbed fermentation-derived cellulose. The non-observed-adverse-effect level (NOAEL) from the present study was concluded to be 5.0% in the diet (5,331 mg/kg body weights/day for males, and 5,230 mg/kg body weights/day for females).


Asunto(s)
Celulosa/efectos adversos , Celulosa/biosíntesis , Fermentación , Gluconacetobacter xylinus/metabolismo , Administración Oral , Animales , Peso Corporal/efectos de los fármacos , Celulosa/administración & dosificación , Celulosa/toxicidad , Ingestión de Líquidos/efectos de los fármacos , Ingestión de Alimentos/efectos de los fármacos , Femenino , Aditivos Alimentarios , Masculino , Nivel sin Efectos Adversos Observados , Ratas , Ratas Endogámicas F344 , Factores de Tiempo , Urinálisis
3.
Biomacromolecules ; 4(6): 1654-60, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-14606892

RESUMEN

The gelation behavior of mixtures of tamarind seed xyloglucan (TSX) and sodium form gellan (Na-G) was investigated. The storage and loss shear moduli, G' and G'', of the mixtures showed that a thermoreversible gel was obtained although each polysaccharide alone did not form a gel at experimental conditions. The viscoelastic behavior of the mixtures showed a gel formation of TSX and Na-G induced by synergistic interaction. This synergistic interaction was also revealed by differential scanning calorimetry (DSC) and circular dichroism. Although TSX alone did not show any peak in DSC curves, mixtures with only a small amount of Na-G, which by itself did not show any peak, showed a single peak. With increasing Na-G content, another peak began to appear at the same temperature at which a peak of Na-G alone appeared. Thermally induced changes in circular dichroism of the mixtures were different from those expected from the individual behavior of TSX and Na-G.


Asunto(s)
Transición de Fase , Polisacáridos/química , Rastreo Diferencial de Calorimetría , Dicroismo Circular , Geles/química , Glucanos/química , Rotación Óptica , Polisacáridos Bacterianos/química , Reología , Temperatura , Xilanos/química
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