Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Induction of an adaptive immune response by vaccination is possible for a broad range of infectious diseases or cancers. Antigen-loaded polymeric nanoparticles have recently been shown to possess significant potential as vaccine delivery systems and adjuvants. Here we demonstrate the use of nanoparticles composed of amphiphilic poly(amino acid) derivatives as vaccine adjuvants. We prepared protein-loaded, biodegradable nanoparticles composed of hydrophobically modified poly(gamma-glutamic acid) (gamma-PGA). gamma-PGA hydrophobic derivatives (gamma-hPGA) formed 200 nm-sized nanoparticles in water. The protein-encapsulated gamma-hPGA nanoparticles were efficiently taken up by immature dendritic cells (iDCs). Interestingly, the nanoparticle uptake by iDCs induced DC maturation. The immunization with human immunodeficiency virus (HIV)-1 gp120-encapsulated nanoparticles strongly induced antigen-specific cellular immunity. These results suggest that antigen-loaded gamma-hPGA nanoparticles provide a novel delivery tool for vaccination against viral infections or tumors. This system has potential application as a universal delivery system for protein-based vaccines capable of inducing cytotoxic T lymphocyte (CTL).
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PMID:Protein direct delivery to dendritic cells using nanoparticles based on amphiphilic poly(amino acid) derivatives. 1748 61

Newly synthesized vanadyl-poly(gamma-glutamic acid) complex (VO-gamma-PGA) with a VO(O4) coordination mode was found to have potent antidiabetic activity in streptozotocin (STZ)-induced type 1 diabetic mice (STZ-mice), compared with that of a solution containing only vanadyl sulfate, VOSO4. This was the first example of orally active vanadyl complex of gamma-PGA for treating STZ-mice. To better define its efficacy, we examined here the effects of VO-gamma-PGA treatment in STZ-mice by oral administration at the dose of 10 mg V/kg body mass for a longer period time than our previous study. The improvement in diabetic states in STZ-mice compared with saline-treated nondiabetic normal Std ddY mice. It was found that the elevated blood glucose levels in STZ-mice significantly decreased after 3 days and sustained the normalized blood glucose level around 180-200 mg/dL (10-11.1 mM) for the last 14 days, which is close to the blood glucose levels 100-200 mg/dL (5.6-11.1 mM) in nondiabetic normal Std ddY mice. The improvement in diabetes was strongly corelated by the improvement in oral glucose tolerance ability, glycosylated hemoglobin (HbA1c) levels and blood pressure, and serum parameters. The present results confirmed that VO-gamma-PGA complex is a promising, orally active insulin-mimetic agent to treat type 1 diabetic mice.
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PMID:Antidiabetic activity of the orally effective vanadyl-poly (gamma-glutamic acid) complex in streptozotocin(STZ)-induced type 1 diabetic mice. 1749 57

The influence of the molecular weight and the type of gelatin (A or B), as well as the molecular weight of poly (gamma-glutamic acid) (gamma-PGA), on the properties of gelatin/gamma-PGA mixed bioadhesives were studied. The gelation of the system was enhanced by a crosslinker, 1-(3-dimethylaminopropyl)-3-(ethylcarbodiimide) hydrochloride (EDC). The gelation time of the bioadhesives was analyzed using rheological measurements. The results indicated that the type of gelatin was a critical factor in determining the gelation time of the biological glues. The mixed glues had greater bonding strength and smaller gelation times as the molecular weight of gamma-PGA or gelatin increased. The swelling ratio decreased and the denaturation temperature increased upon raising the EDC concentration, indicating a greater degree of crosslinking at higher EDC concentrations. The mixed glues crosslinked with various concentrations of EDC (1.7-2.5%) showed no cytotoxicity to fibroblasts. In addition, no significant inflammatory response was observed in the rat subcutaneous implantation. The bioadhesives based on gelatin/gamma-PGA remained at the site for 7 days while the fibrin glue had almost completely degraded. By choosing the appropriate gelatin type and higher molecular weight gamma-PGA in the mixtures, the gelatin/gamma-PGA biological glues could serve as soft tissue adhesives. Rheological characterization was essential in the evaluation of biological glues.
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PMID:The properties of gelatin-poly (gamma-glutamic acid) hydrogels as biological glues. 1750 86

Tomato pulp waste, a byproduct obtained during the processing of tomato juice, has been shown to be a rich source of lycopene. The objectives of this study were to use gelatin and poly(gamma-glutamic acid) (gamma-PGA) as coating materials for the encapsulation of lycopene extract from tomato pulp waste. Initially, lycopene was extracted with supercritical carbon dioxide, followed by microencapsulation using an emulsion system consisting of 4.5% gelatin, 10% gamma-PGA, and 4.8% lycopene extract. Analysis of differential scanning calorimetry revealed that the thermal stability of the coating material could be up to 120 degrees C, with a mean particle size of 38.7 microm based on Coulter counter analysis. The total weight of microencapsulated powder was 617 microg with the yield of lycopene being 76.5%, indicating a 23.5% loss during freeze drying. During storage of microencapsulated powder, the concentrations of cis-, trans-, and total lycopene decreased along with increasing time and temperature. A fast release of lycopene in the powder occurred at pH 5.5 and 7.0, while no lycopene was released at pH 2.0 and 3.5.
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PMID:Encapsulation of lycopene extract from tomato pulp waste with gelatin and poly(gamma-glutamic acid) as carrier. 1754 4

Macromolecular and polyanionic Na(+)-poly(gamma-glutamic acid) (PGA) silver nitrate complex acted as both a metal ion provider and a particle protector to fabricate nanosized silver colloids under chemical reduction by dextrose. The formation and size of particles have been characterized from transmission electron microscopy (TEM), dynamic light scattering analysis and UV-vis spectrophotometer. The results showed that the average particle size was 17.2+/-3.4 to 37.3+/-5.5 nm, apparently depending on the complex concentration. It was found that the rate constant and conversion of silver nanoparticles were proportional to the concentration of PGA. The growth mechanism of nanosized silver colloid was fully discussed. In addition, the in vitro cytotoxicity evaluated by L929 fibroblasts proliferation and antibacterial activity against Gram-positive strain (methicillin-resistant S. aureus (MRSA)) and Gram-negative strain (P. aeruginosa) bacteria have been assessed.
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PMID:Formation of colloidal silver nanoparticles stabilized by Na+-poly(gamma-glutamic acid)-silver nitrate complex via chemical reduction process. 1758 83

Dipalmitoylphosphatidylcholine (DPPC) bilayer was created on the surface of an exponentially growing poly(glutamic acid)/poly(lysine) (PGA/PLL) layer-by-layer polyelectrolyte film. The lipid bilayer decreased the surface roughness of the polyelectrolyte film. The layer-by-layer construction of the polyelectrolyte film could be continued on the top of the DPPC layer. The lipid bilayer, however, formed a barrier in the interior of the polyelectrolyte film, which blocked the diffusion (a prerequisite for exponential growth) of the polyelectrolytes. Thus, a new growth regime started in the upper part of the polyelectrolyte film, which was added to embed the DPPC bilayer. The structure and the dynamics of the DPPC bilayer on the polyelectrolyte film surface remained similar to that of its hydrated multibilayers, except that the phase transition became wider. In the case of embedded DPPC bilayers, in addition, the phase-transition temperature also decreased. This is the result of interactions with the nonconcerted movements of the barrier-separated lower and higher parts of the polyelectrolyte film. Gramicidin A (GRA) as a model of lipid-soluble peptides and proteins was successfully incorporated into such DPPC films. The DPPC films, either with or without GRA, were remarkably stable; as many heating-cooling cycles to measure phase transition could be carried out without visible alterations as wanted.
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PMID:Phospholipid bilayers as biomembrane-like barriers in layer-by-layer polyelectrolyte films. 1758 91

The mainstream of recent anti-AIDS vaccines is a prime/boost approach with multiple doses of the target DNA of human immunodeficiency virus type 1 (HIV-1) and recombinant viral vectors. In this study, we have attempted to construct an efficient protein-based vaccine using biodegradable poly(gamma-glutamic acid) (gamma-PGA) nanoparticles (NPs), which are capable of inducing potent cellular immunity. A significant expansion of CD8+ T cells specific to the major histocompatibility complex class I-restricted gp120 epitope was observed in mice intranasally immunized once with gp120-carrying NPs but not with gp120 alone or gp120 together with the B-subunit of cholera toxin. Both the gp120-encapsulating and -immobilizing forms of NPs could induce antigen-specific spleen CD8+ T cells having a functional profile of cytotoxic T lymphocytes. Long-lived memory CD8+ T cells could also be elicited. Although a substantial decay in the effector memory T cells was observed over time in the immunized mice, the central memory T cells remained relatively constant from day 30 to day 238 after immunization. Furthermore, the memory CD8+ T cells rapidly expanded with boosting with the same immunogen. In addition, gamma-PGA NPs were found to be a much stronger inducer of antigen-specific CD8+ T-cell responses than nonbiodegradable polystyrene NPs. Thus, gamma-PGA NPs carrying various HIV-1 antigens may have great potential as a novel priming and/or boosting tool in current vaccination regimens for the induction of cellular immune responses.
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PMID:Induction of potent CD8+ T-cell responses by novel biodegradable nanoparticles carrying human immunodeficiency virus type 1 gp120. 1760 61

Layer-by-layer (LBL) polyelectrolyte films offer extensive potentials to enhance surface properties of vascular biomaterials. From the time of implantation, PET prostheses are continuously subjected to multiple mechanical stresses such as important distorsions and blood pressure. In this study, three LBL films, namely (1) poly(sodium 4-styrenesulfonate)/poly(allylamine hydrochloride), (2) poly(L-lysine)/hyaluronan, and (3) poly(L-lysine)/poly(L-glutamic acid) were built on to isolated PET filaments, thread, and vascular prostheses. The three LBL films uniformly covered the surface of the PET samples with rough, totally smooth, and "wrinkled" appearances respectively for (PAH/PSS)(24), (PLL/HA)(24), and (PLL/PGA)(24) systems. We then assessed the behavior of these LBL films, in an aqueous environment [by environmental scanning electronic microscopy (ESEM)], when subjected to unidirectional longitudinal stretches. We found that stretching induces ruptures in the multilayer films on isolated filaments for longitudinal stretches of 14% for (PSS/PAH)(24), 13% for (PLL/PGA)(24), and 30% for (PLL/HA)(24) films. On threads, the rupture limit is enhanced to be respectively 26, 20, and 28%. Most interestingly, we found that on vascular prosthesis no rupture is visible in any of the three multilayers types, even for elongations of 200% (200% undergone by the PET prostheses is representative of those encountered during graft deployment) which by far exceeds elongations observed under physiological conditions (10-20%, blood pressure). In term of mechanical behaviors, these preliminary data constitute a first step toward the possible use of LBL film to coat and functionalize vascular prosthesis.
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PMID:Characterization of polyelectrolyte multilayer films on polyethylene terephtalate vascular prostheses under mechanical stretching. 1761 82

A Bacillus subtilis strain B6-1, previously isolated from the rhizosphere of vegetable, selectively produced antibiotics or poly-gamma-glutamic acid (gamma-PGA) in two kinds of liquid media and their co-productions were obtained when using soybean and sweet potato residues in solid-state fermentation. The antibiotics were purified and identified as fengycins. After these residue cultures were introduced, cucumber wilts were effectively suppressed. The introduction also significantly increased the dry weights of roots and shoots of cucumber seedlings, and the roots to shoots ratio, especially at lower nutrition, which indicated the fertilizer synergistic effects. So the product of soybean and sweet potato residues, cultivated with B6-1 co-producing lipopeptides and gamma-PGA, can be expected to be used as both biocontrol agents and fertilizer synergists.
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PMID:Co-producing lipopeptides and poly-gamma-glutamic acid by solid-state fermentation of Bacillus subtilis using soybean and sweet potato residues and its biocontrol and fertilizer synergistic effects. 1768 65

Preparation of a poly (gamma-glutamic acid)-cisplatin conjugate was introduced and its in vitro antitumor effect was investigated. Poly (gamma-glutamic acids) was obtained by using fermentation methods. The hydrolyzed small molecular weight of poly (gamma-glutamic acids) was prepared by acid hydrolysis. The interaction between poly (gamma-glutamic acids) -cisplatin conjugate (PGA-CDDP) and DNA was investigated by PCR model. MTT assay was used to investigate the in vitro anticancer activity of the conjugate. Apoptosis assay of the conjugate was investigated by FCM assay and the in vivo toxicity was also proceeded. The results showed that the poly (gamma-glutamic acids) -cisplatin conjugate was obtained successfully and its yield is 10% - 12%. It has obvious antitumor effects on human liver tumor BEL7404 cells, human lung tumor H446 cells and human colon tumor RKO cells. At the same time, it also has apoptosis effects on the three kinds of tumor cell lines. The in vivo toxicity of PGA-CDDP was examined in normal mice and the results showed that the in vivo toxicity of this conjugate was significantly lower than that of free CDDP. In conclusion, the poly (gamma-glutamic acids) -cisplatin conjuate could be used as a potential clinic antitumor drug. The poly (gamma-glutamic acids) obtained by fermentation can be used as a valuable drug carrier system.
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PMID:[Preparation and biological activity of poly (gamma-glutamic acid) -cisplatin conjugate]. 1770 97


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