ABSTRACT
Four hydrophilic polymers in the form of beads - chitosan, alginate, alginate/polyvinyl alcohol (PVA), and chitosan-coated alginate - were used as supports for lipase immobilisation. Hydrogel beads were characterised by bead-size-distribution estimation, surface morphology studies, and polymer interactions assessment. Matrix performances - loading efficiency, immobilisation yield, enzyme activity, and stability retention - were evaluated and compared. Although the loading efficiency of the chitosan-coated Ca-alginate beads (79.8%) was inferior to that of the Ca-alginate (87%) and of the Ca-alginate/PVA beads (81.3%), their enzyme immobilisation yield (63.96%) was the most important. Moreover, lipase encapsulated in chitosan-coated Ca-alginate beads demonstrated better pH, thermal, and storage (89% residual activity after 30 days) stabilities. Immobilised lipase activity also increased in the order: alginate/PVA > chitosan > alginate > alginate/chitosan, and displayed a maximum at pH 8 and at temperatures of 45 °C (chitosan and Ca-alginate/PVA beads) and 50 °C (Ca-alginate and chitosan-coated Ca-alginate beads). Thus, chitosan-coated Ca-alginate beads could be considered as a suitable support for lipase immobilisation.
ABSTRACT
BACKGROUND: It is well documented that Giardia duodenalis undergoes surface antigenic variation both in vivo and in vitro. Proteins involved have been characterized and referred to as VSP (variable surface protein). METHODS: Two cloned cDNA inserts of 0.45 and 1.95 kb were obtained from G. duodenalis expression library and sequenced. Comparison sequence analyses were made against Genbank. PCR analysis was performed on G. duodenalis isolates to identify isolates bearing genes encoding such a peptide. Specific antiserum was prepared against 450-bp encoded peptide and tested by Western blot, immunofluorescence, and inhibition of adhesion of G. duodenalis to target cells. RESULTS: We cloned and characterized a G. duodenalis 450-bp DNA fragment; its DNA sequence analysis revealed that this fragment displayed 99% identity with vsp9B10A gene. Predicted amino acid sequence for this fragment also had significant (99%) identity to VSP9B10A. A second 1.95-kb insert, which encompassed the 450-bp cDNA fragment, was also isolated; its DNA and amino acid sequence displayed 99.5% identity with vsp9B10A gene and 99.2% with the corresponding inferred protein, respectively. This inferred protein contained 24 Cys-X-X-Cys motifs and long ORF of 642 aminoacids. PCR analysis showed that DNA sequence encoding a fragment of this gene was present in P1, CIEA:0487:2-C-8 clone and in INP:180800-B2 G. duodenalis human isolates, while it was absent in sheep isolate of G. duodenalis INP:150593-J10. CONCLUSIONS: Immunofluorescence analysis using antibodies raised against the peptide encoded by 450-bp fragment showed that expression of this epitope varies on trophozoite surface of the C-8 Mexican clone and is involved in parasite adhesion to target epithelial cells.
Subject(s)
Giardia/metabolism , Amino Acid Sequence , Animals , Antigens, Protozoan/chemistry , Base Sequence , Blotting, Western , Cell Adhesion , Cell Line , Child, Preschool , Cloning, Molecular , DNA/chemistry , DNA, Complementary/metabolism , Dogs , Epitopes/chemistry , Gene Library , Genetic Variation , Giardiasis/immunology , Humans , Kinetics , Mexico , Mice , Mice, Inbred BALB C , Microscopy, Fluorescence , Molecular Sequence Data , Peptides/chemistry , Polymerase Chain Reaction , Protein Structure, Tertiary , Protozoan Proteins/chemistry , Recombinant Fusion Proteins/chemistry , Sheep , Time FactorsABSTRACT
Objetivo. Determinar las variaciones de un conjunto indicadores del metabolismo de lípidos en muestra de mujeres sanas durante el tercer trimestre del embarazo y los períodos de 3 y 6 meses postparto y su asociación con la tensión arterial e índices de cantidad y distribución de grasa corporal. Material y métodos. Se evaluó una muestra de 15 embarazadas sanas en el último trimestre de la gestación y a los tres y seis meses postparto. A cada mujer se le determinó la tensión arterial, y se realizó una evaluación antropométrica y bioquímica con la finalidad de describir la modificación del perfil de lípidos en el período estudiado, y la asociación de estos indicadores con las mediciones antropométricas. Resultados. Se identificaron diferencias significativas en las concentraciones de lípidos entre los valores observados durante la gestación y los de los períodos subsecuentes. Los indicadores antropométricos señalan que las mujeres del estudio tendieron a incrementar su peso y grasa corporal. No se encontraron asociaciones significativas entre los indicadores antropométricos, bioquímicos y la tensión arterial. Conclusión. Los indicadores de lípidos y la tensión arterial disminuyen durante el periodo estudiado con respecto al embarazo. No se observó esta tendencia en los indicadores antropométricos