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PubMed1981

Adjuvant and suppressive effects of Grass Conjuvac and other alginate conjugates on IgG and IgE antibody responses in mice.

BALB/c mice were immunized with grass pollen extract (GPE), GPE conjugated to sodium alginate (Conjuvac) or GPE absorbed to aluminium hydroxide gel (alum). Conjuvac was a more potent immunogen than the other two preparations of GPE when anti-GPE IgG antibody levels were compared. In contrast, the highest IgE antibody titres in the Conjuvac treated mice, were some sixteen-fold lower than the highest titres in the mice immunized with GPE in alum. The suppressive effects of Conjuvac on IgE antibody titres were also studied. Mice were immunized with 1 microgram dinitrophenyl (DNP)-GPE in alum and the anti-DNP and anti-GPE IgE antibody titres determined. After 4 and 5 weeks, the mice were injected with GPE or Conjuvac. The Conjuvac and the GPE failed to reduce the ongoing primary anti-GPE IgE responses but both suppressed the secondary responses by up to eight-fold. The suppression was not dose-related however. The ongoing primary and secondary anti-DNP IgE titres were suppressed in a dose-related manner by up to sixty-four fold by Conjuvac but GPE treatment was much less suppressive. We went on to investigate the suppressive properties of DNR-alginate (DNP-alg) conjugates. In these experiments mice were immunized with 1 microgram DNP-ovalbumin (DNP-OA) mixed with alum. After 4 and 5 weeks, the mice were injected with a dose of 6--600 micrograms DNP-alg with an average hapten density of 2 or 10 per alginate molecule. After a further 8 weeks a second injection of 1 microgram DNP-OA was given. All dose levels of both DNP-alg conjugates suppressed the continuing primary as well as the secondary anti-DNP IgE responses. It is concluded that alginate has properties similar to those of known T-cell adjuvants and that Conjuvac may prove useful in the immunotherapy of atopic allergy.

Adjuvants, Immunologic↗
PubMed1996

The use of chitosan to increase the stability of calcium alginate beads with entrapped yeast cells.

A method was developed for increasing the stability of calcium alginate beads with entrapped Saccharomyces cerevisiae cells. Polyelectrolyte complexes were used as surface-coating materials by dropping alginate into chitosan. The coacervation agent sodium triphosphate was needed for the formation of the polyelectrolyte complexes. Gel beads maintained their rigidity during ethanol production and were chemically stable in phosphate buffer. No differences in ethanol production were found between S. cerevisiae immobilized in calcium alginate and in calcium alginate coated with polyelectrolyte complexes. The maximum productivity by immobilized S. cerevisiae cells was 74.1 g of ethanol/h per g of gel beads obtained at pH 4.8-6.0 and at 30 degrees C.

Alginates↗
PubMed1997

Calcium alginate as haemostatic swabs in hip fracture surgery.

Blood loss as a consequence of internal fixation of intertrochanteric fractures of the proximal femur was measured in two groups to compare the haemostatic effect of calcium alginate fibre swabs with that of simple gauze swabs. The patients in the gauze swab group lost 139.4 +/- 9.6 mL per-operatively, whilst those in the alginate swab group lost 98.8 +/- 9.9 mL (P < 0.01). The post-operative suction drainage loss in the gauze group was 158.4 +/- 17.3 mL, and that in the alginate swab group was 96.6 +/- 11.7 mL (P < 0.01). This study shows that alginate swabs significantly decrease per-operative blood loss and post-operative suction drainage loss, and suggests that haemostatic swabs could have wider applications in orthopaedic surgery.

Aged↗
PubMed2000

Alginate hydrogel linked with synthetic oligopeptide derived from BMP-2 allows ectopic osteoinduction in vivo.

Bone morphogenetic proteins (BMP) are unique molecules with a specific biological activity for inducing ectopic bone formation when implanted with a suitable carrier matrix. However, incorporation of BMP into the carrier has disadvantages, including early burst release and protein degradation in biological environments. Therefore, we considered that the next greatest challenge in achieving successful clinical use was the development of a carrier system for site-specific delivery of the morphogenetic signal of BMP. In this study, a novel BMP-2-derived oligopeptide, NSVNSKIPKACCVPTELSAI, was coupled covalently to alginate. Then NSVNSKIPKACCVPTELSAI-linked alginate hydrogel composites were implanted into the calf muscle of rats and harvested 3 or 8 weeks after surgery. Ectopic bone formation was observed in alginate hydrogel linked with BMP-2-derived peptide. It is suggested that alginate hydrogel linked with an oligopeptide derived from BMP-2 might provide an alternative system for topical delivery of the morphogenetic signal of BMP-2.

Amino Acid Sequence↗
PubMed2001

Chitosan-alginate films prepared with chitosans of different molecular weights.

Chitosan-alginate polyelectrolyte complex (CS-AL PEC) is water insoluble and more effective in limiting the release of encapsulated materials compared to chitosan or alginate. Coherent CS-AL PEC films have been prepared in our laboratory by casting and drying suspensions of chitosan-alginate coacervates. The objective of this study was to evaluate the properties of the CS-AL PEC films prepared with chitosans of different molecular weights. Films prepared with low-molecular-weight chitosan (Mv 1.30 x 10(5)) were twice as thin and transparent, as well as 55% less permeable to water vapor, compared to films prepared with high-molecular-weight chitosan (Mv 10.0 x 10(5)). It may be inferred that the low-molecular-weight chitosan reacted more completely with the sodium alginate (M(v) 1.04 x 10(5)) than chitosan of higher molecular weight. A threshold molecular weight may be required, because chitosans of Mv 10.0 x 10(5) and 5.33 x 10(5) yielded films with similar physical properties. The PEC films exhibited different surface properties from the parent films, and contained a higher degree of chain alignment with the possible formation of new crystal types. The PEC films exhibited good in vitro biocompatibility with mouse and human fibroblasts, suggesting that they can be further explored for biomedical applications.

Animals↗
PubMed2001

The release of alginate lyase from growing Pseudomonas syringae pathovar phaseolicola.

Pseudomonas syringae pathovar phaseolicola, which produces alginate during stationary growth phase, displayed elevated extracellular alginate lyase activity during both mid-exponential and late-stationary growth phases of batch growth. Intracellular activity remained below 22% of the total activity during exponential growth, suggesting that alginate lyase has an extracellular function for this organism. Extracellular enzyme activity in continuous cultures, grown in either nutrient broth or glucose-simple salts medium, peaked at 60% of the washout rate, although nutrient broth-grown cultures displayed more than twice the activity per gram of cell mass. These results imply that growth rate, nutritional composition, or both initiate a release of alginate lyase from viable P. syringae pv. phaseolicola, which could modify its entrapping biofilm.

Plant Diseases↗
PubMed2004

Crystal structure of the alginate (poly alpha-l-guluronate) lyase from Corynebacterium sp. at 1.2 A resolution.

The crystal structure of alginate (poly alpha-l-guluronate) lyase from Corynebacterium sp. (ALY-1) was determined at 1.2A resolution using the MAD method and bromide ions. The structure of ALY-1 is abundant in beta-strands and has a deep cleft, similar to the jellyroll beta-sandwich found in 1,3-1,4-beta-glucanase. The structure suggests that alginate molecules may penetrate into the cleft to interact with the catalytic site of ALY-1. The reported crystal structure of another type of alginate lyase, A1-III, differs from that of ALY-1 in that it consists almost entirely of alpha-helical structure. Nevertheless, the putative catalytic residues in both enzymes are positioned in space in nearly identical arrangements. This finding suggests that both alginate lyases may have evolved through convergent evolution.

Amino Acid Sequence↗
PubMed2001

Cloning, sequence analysis and expression of Pseudoalteromonas elyakovii IAM 14594 gene (alyPEEC) encoding the extracellular alginate lyase.

A gene (alyPEEC) encoding an alginate lyase of Pseudoalteromonas elyakovii IAM 14594 was cloned using the plasmid vector pUC118 and expressed in Escherichia coli. Sequencing of a 3.0kb fragment revealed a 1,197bp open reading frame encoding 398 amino acid residues. The calculated molecular mass and isoelectric point of the alyPEEC gene product are 43.2 kDa and pI 5.29. A region G(165) to V(194) in the AlyPEEC internal sequence is identical to the N-terminal amino acid sequence of the previously purified extracellular alginate lyase of P. elyakovii, and the calculated molecular mass (25.4 kDa) and isoelectric point (pI 4.78) of the region resembled those of the purified enzyme. Expression of enzymically-active alginate lyase from alyPEEC required growth of recombinant E. coli in LB broth containing 50% (v/v) artificial seawater (ASW). Alginate lyase activity with broad substrate specificity was detected in both 42 and 30 kDa products. Subcloning of the region G(165) to N(398) of AlyPEEC corresponding to the 30 kDa protein confirmed that this region of the alyPEEC gene encoded the active site of the enzyme. A region A(32) to G(164) corresponding to about 13 kDa of the N-terminal region of AlyPEEC showed about 30% identity to a putative chitin binding domain of Streptomyces chitinases, but did not exhibit any catalytic activity.

Amino Acid Sequence↗
PubMed2000

Glucose oxidase release from calcium alginate gel capsules.

Diffusion of glucose oxidase within calcium alginate gel capsules has been assayed and the experimental data fitted to a simple semi-empirical power equation, which is used to analyse the solute release from polymeric devices. It was found that an increase in the concentration of sodium alginate and calcium chloride gives rise to a reduction in the enzyme leakage. This was verified when glucose oxidase (GOD) diffusion percentages were compared in capsules with thicknesses of the same order of magnitude but obtained under different experimental conditions. So, the use of sodium alginate and calcium chloride solutions of concentrations 0.5% w/v and 2.6% w/v, respectively, lead to a diffusion percentage of 25 +/- 2. This percentage was reduced to 8 +/- 3 when sodium alginate and calcium chloride concentrations were fixed at 1% w/v and 4% w/v, respectively, even though the thicknesses of the capsules were of the same order of magnitude.

Journal Article↗
PubMed2004

Evaluation of mass-transfer characteristics in alginate-membrane liquid-core capsules prepared using polyethylene glycol.

An alginate-membrane liquid-core capsule prepared using polyethylene glycol as a thickener was produced and the intracapsular mass-transfer characteristics of glucose and proteins were investigated. The apparent effective diffusivity of glucose into the capsule was 7.9x10(-10) m(2)/s, which is larger than that into alginate beads (6.5x10(-10) m(2)/s) and in water (6.7x10(-10) m(2)/s). Moreover, an encapsulation of strawberry cells did not decrease the mass transfer performance of glucose, in contrast to the case of immobilization in alginate beads or capsules prepared using xanthan gum. On the other hand, the apparent effective diffusivities of proteins from the capsule were smaller than those in alginate beads. In addition, the apparent effective diffusivities from the capsule decreased with the increasing concentration and molecular weight of polyethylene glycol used as a thickener during capsule preparation.

Journal Article↗
PubMed2006

Crystallization and preliminary X-ray analysis of an exotype alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, a member of polysaccharide lyase family 15.

Almost all alginate lyases depolymerize alginate in an endolytical fashion via a beta-elimination reaction. The alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, consisting of 776 amino-acid residues, is a novel exotype alginate lyase classified into polysaccharide lyase family 15. The enzyme was crystallized at 293 K by sitting-drop vapour diffusion with polyethylene glycol 4000 as a precipitant. Preliminary X-ray analysis showed that the Atu3025 crystal belonged to space group P2(1) and diffracted to 2.8 angstroms resolution, with unit-cell parameters a = 107.7, b = 108.3, c = 149.5 angstroms, beta = 91.5 degrees.

Agrobacterium tumefaciens↗
PubMed1997

Influence of macrolides on mucoid alginate biosynthetic enzyme from Pseudomonas aeruginosa.

OBJECTIVE: The long-term administration of erythromycin (EM), clarithromycin (CAM) or azithromycin (AZM) has generally resulted in a favorable outcome for patients with diffuse panbronchiolitis (DPB) infected with mucoid Pseudomonas aeruginosa. To elucidate the mechanism involved, the influence of macrolides on mucoid alginate production by P. aeruginosa was investigated in vitro. METHODS: The macrolides used in this study were EM with a 14-membered ring, AZM with a 15-membered ring, midecamycin (MDM) with a 16-membered ring, and CP-4305, which has had mycarose removed from MDM, The effects of macrolides on mucoid P. aeruginosa were investigated by quantitative assay of alginate production and inhibition of guanosine diphospho-D-mannose dehydrogenase activity. RESULTS: After incubation with EM, AZM and CP-4305, the structural material of P. aeruginosa biofilm was distorted, and the enzymatic activity of GDP-D-mannose dehydrogenase, the most important enzyme in mucoid alginate biosynthesis, was inhibited. However, these effects were not observed with the 16-membered macrolide MDM. CONCLUSIONS: The basic mechanism of clinical efficacy seen characteristically in 14- or 15-membered macrolides for patients with airway biofilm disease depends on the ability of such macrolides to inhibit alginate production by P. aeruginosa. Furthermore, this suggests that the inhibitory effect observed with 14-, 15- and 16-membered macrolides may depend on the sugar chain connected with the macrolide ring.

Journal Article↗
PubMed1987

Influence of Alginate on Attachment of Vibrio spp. to Stainless Steel Surfaces in Seawater.

The influence of alginate on the attachment of Vibrio alginolyticus and Vibrio pelagius biovar II to stainless steel was investigated. When the bacteria were in stationary phase, alginate decreased the number of attached bacteria in the case of each Vibrio sp. In contrast, when V. pelagius biovar II was grown on alginate and harvested in log phase, attachment was increased. This effect may be due to nutrient availability at the surface or to receptors on the bacterial surface which interact with alginate adsorbed to the metal.

Journal Article↗
PubMed1990

Method designed to detect alginate-degrading bacteria.

A simple turbidimetric method was developed to detect alginate degradation. Bacteria were grown in alginate-containing media, and culture fluids were mixed with an acidic albumin solution. Failure to develop a white turbidity indicated an alginate degrader. The method showed alginate degradation by Vibrio alginolyticus ATCC 17749, in contrast to prior descriptions.

Journal Article↗
PubMedDate not supplied

Alginate polylysine microcapsules as immune barrier: permeability of cytokines and immunoglobulins over the capsule membrane.

Transplantation of pancreatic islets in alginate polylysine microcapsules is a potential useful method for treating type I diabetes. In this study, the permeability for alginate-polylysine microcapsules to cytokines an immunoglobulines has been investigated by a newly developed method. Magnetic monodisperse polymer particles (Dynabeads) coated with antibodies against selected proteins were encapsulated in 0.7 mm alginate polylysine microcapsules. The capsule membrane permeability to IgG (150 kDa), Transferrin (81 kDa), Tumor necrosis factor (TNF, 51 kDa), Interleukin-1 beta (IL-1 beta, 17.5 kDa), and insulin (5.8 kDa) was estimated by measuring the binding of 125I-labeled proteins to the encapsulated antibody coated Dynabeads. Capsules with an inhomogeneous solid gel core were made of alginates with high guluronic or high mannuronic acid content and poly-L (PLL)- or poly-D-lysine (PDL) of concentrations varied from 0.05-0.2%. The various capsules examined were all impermeable to IgG. The capsules made with a PLL-, but not PDL-membranes were permeable for transferrin. IL-1 beta was found to penetrate all of the different capsule types. The high-G capsules, however, could be made impermeable to TNF and still allowed transferrin to pass. The permeability of these capsules to IL-1 beta, but not to TNF was confirmed in an assay where mouse islets of Langerhans were incubated with TNF and IL-1 beta, and comparing the IL-6 for encapsulated and non-encapsulated islets.

Animals↗
PubMed1999

Electrophoretic extraction and analysis of DNA from chitosan or poly-L-lysine-coated alginate beads.

Alginate beads containing entrapped DNA were produced using both external and internal calcium sources, and coated with chitosan or poly-L-lysine membranes. The beads were assayed with DNase nuclease to determine formulation conditions offering the highest level of DNA protection from nucleic acid hydrolysis, simulating gastrointestinal exposure. A method was developed to extract and assay intracapsular DNA through a modified agarose electrophoresis system. Both external and internally gelled beads were permeable to DNase (Mw = 31 kDa), indicated by the absence of DNA after nuclease exposure. At low levels of DNase exposure, coated high guluronic content alginate beads offered a higher level of DNA protection compared with coated beads with low guluronic alginate. No apparent correlation was found with chitosan membrane molecular weight and degree of deacetylation; however, increasing poly-L-lysine molecular weight appeared to increase DNase exclusion from beads. At elevated levels of DNase exposure, DNA hydrolysis was evident within all coated beads with the exception of those coated with the highest molecular weight poly-L-lysine (Mw = 197.1 kDa), which provided almost total nuclease protection. Optimal combination then for DNA protection from nucleases is a high guluronic alginate core, coated with high molecular weight poly-L-lysine.

Journal Article↗
PubMed2006

Validity and reliability of an alginate method to measure body surface area.

The purpose of this study was to evaluate the validity and reliability of coating methods (plaster bandage, inelastic tape, and the alginate method) and an indirect method using a three dimensional (3D) whole body scanner. The surface area of geometric solids was measured five times using the three coating methods, and analyzed through 2D scanning and a planimeter. Second, to examine the accuracy of the alginate method more closely, the surface areas of boards with different surface properties at various inclines were measured and compared. Lastly, the surface area of a human arm was measured using the three coating methods and a 3D scanning method. The results are as follows: 1) The three coating methods were statistically valid and reliable for measuring the surface area of geometric solids. 2) The planimeter was rejected because the mean error was bigger than in 2D scanning. 3) The method showing the least error was the inelastic tape method, but that method was not recommended because it was too tiresome and laborious. 4) The greater the curvature and smaller the size of a geometric solid, the greater the error. 5) In measuring surface area using the alginate method, the objects that were smoother and had steeper angles showed a greater surface area: however, the mean error was less than 1%. 6) In measuring a human arm, the surface area obtained by 3D scanning was less than any other surface area obtained in the three coating methods, because the 3D scanner could not discern the armpit and fingers. In conclusion, the method using alginate was statistically valid and reliable in the measuring of surface area both of geometric solids and real human skin.

Anthropometry↗
PubMed1999

Preparation and distribution of 5-fluorouracil (125)I sodium alginate-bovine serum albumin nanoparticles.

AIM:To prepare 5-FU sodium alginate(125)I bovine serum albumin nanoparticles (BSA NP), to determine the radioactive count in different organs of rats at different time points after oral administration of 5-FU (125)I sodium alginate-BSA NP and to calculate the kinetic parameters of its metabolism.METHODS:Emulsion solidification method was used to prepare 5-FU (125)I sodium alginate-BSA NP, and to determine its diameter under transmission electronic microscope (TEM). Then the rate of NP and external drug releasing velocity were measured. Radioactive counting in different organs of rats was made after oral administration of the NP by GAMA Counter, and the kinetic parameters of drug metabolism were calculated by handling the data with the two-department model.RESULTS:The average arithmatic diameter of the NP was 166nm ± 34nm, the rate of 5-FU was 32.8% and the cumulative external releasing ratio amounted to 84.0% within 72 hours. The NP was mainly distributed in the liver, spleen, lungs and kidneys after NP oral administration to rats. The micro-radioautographic experiment showed that NP was distributed in the Kupffers cells of liver, liver parenchymal cells and the phagocytes of spleen and lungs. The kinetic parameters of matabolism were: T(1/2) = 9.42h, C(max) = 2.45X10(7)Bq,T(max) = 2.18h, AUC = 148X10(9)Bq.CONCLUSION:NP is difficult to pass through the blood-cerebral barrier,and (125)I sodium alginate-BSA NP enters the body-circulation by gastroin testinal passage.

Journal Article↗