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PubMed2005

The use of amino acids to enhance the aerosolisation of spray-dried powders for pulmonary gene therapy.

BACKGROUND: Pulmonary delivery of gene therapy offers the potential for the treatment of a range of lung conditions, including cystic fibrosis, asthma and lung cancer. Spray-drying may be used to prepare dry powders for inhalation; however, aerosolisation of such powders is limited, resulting in poor lung deposition and biological functionality. In this study, we examine the use of amino acids (arginine, aspartic acid, threonine, phenylalanine) to enhance the aerosolisation of spray-dried powders containing model non-viral gene vectors. METHODS: Lipid/polycation/pDNA (LPD) vectors, in the presence or absence of amino acids, were dispersed in lactose solutions, and spray-dried to produce appropriately sized dry powders. Scanning electron microscopy and laser diffraction were used to determine particle morphology and diameter, respectively. Gel electrophoresis was used to examine the influence of amino acids on the structural integrity of the LPD complex. In vitro cell (A549) transfection was used to determine the biological functionality of the dry powders, and the in vitro aerosolisation performance was assessed using a multistage liquid impinger (MSLI). RESULTS: Both gel electrophoresis and in vitro cell transfection indicated that certain amino acids (aspartic acid, threonine) can adversely affect the integrity and biological functionality of the LPD complex. All amino acids significantly increased the aerosolisation of the powder, with the arginine and phenylalanine powders showing optimal deposition in the lower stages of the MSLI. CONCLUSIONS: Amino acids can be used to enhance the aerosolisation of spray-dried powders for respiratory gene delivery, allowing the development of stable and viable formulations for pulmonary gene therapy.

Administration, Inhalation↗

PubMed2006

Cooperative effect of factors governing molecular ion yields in desorption/ionization mass spectrometry.

Factors governing the molecular ion yields of amino acids and peptides have been studied using fast atom bombardment (FAB) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) in positive-ion mode. The ion yields of protonated amino acids under FAB conditions are dependent on proton affinity (PA), hydrophobicity, and aromaticity of amino acids. Both PA and hydrophobicity contribute to an increase in the ion yields, while aromaticity contributes to a decrease. In MALDI, the ion yields increase linearly with the increase of PA of amino acids with the exception of lysine. In both FAB and MALDI experiments with peptides, the presence of arginine residues is essential for producing abundant protonated peptides. In FAB, the presence of aliphatic and hydrophobic amino acids (leucine and isoleucine) increases the ion yields of protonated peptides, while some hydrophilic amino acids (aspartic acid and asparagines) decrease the ion yields. The presence of two or more arginine residues does not give higher ion yields in FAB. In MALDI, the presence of aromatic amino acids (phenylalanine and tyrosine) enhances the signals for protonated peptides. Thus, physicochemical factors of individual amino acids cooperatively affect the ion yields of protonated amino acids and peptides. These factors governing the ion yields in FAB and MALDI affect two processes, desorption and ionization, that can be considered independently.

Angiotensins↗

PubMed1993

Glucose metabolism in mammalian cells as determined by mass isotopomer analysis.

A method using 13C isotopes and GCMS/SIM was developed and was used to study glucose metabolism in several mammalian cell lines. Using [U-13C6]glucose, the 13C isotopomer distributions in glucose, lactic acid, glutamic acid, aspartic acid, and gamma-aminobutyric acid produced by the cells were determined, and glycolysis, gluconeogenesis, and the flux into the amino acid pools were calculated. A 1:1 mixture of [U-13C6]glucose and [1-13C]glucose was used to examine the loss of 1-13C carbon from [1-13C]glucose via the pentose monophosphate pathway in the cells; this new method measures the production of [3-13C]lactic acid and [U-13C3]lactic acid, and thus avoids most systematic errors that result from the endogenous production of 12C-lactic acid during metabolic conversion; in addition, glycolysis and the recycling of glucose and lactic acid can be examined at the same time. The mass isotopomer analysis method is reproducible and sensitive, and can be used to analyze metabolites in 10(-7) M concentration with less than 10(5) cultured human cells. This method was used to examine metabolic regulation of glucose in fibroblasts, lymphoblasts, and PC12 cells under various conditions of metabolic disturbance. The method appears to have wide applicability for the study of metabolic regulation of glucose and metabolic defects in cells.

Animals↗

PubMed2002

Identification and fine mapping of IgG and IgE epitopes in ovomucoid.

Ovomucoid is a major allergen in hen egg white which causes a serious IgE-mediated food allergy reaction. This study determined eight IgG epitopes, 5-11 amino acids in length, and nine IgE epitopes, 5-16 amino acids in length, within the primary sequence in ovomucoid using arrays of overlapping peptides synthesized on cellulose membranes. Pooled sera from eight egg-allergic patients were used to probe the membrane. We also analyzed the amino acids that are critical for antibody binding by substituting a single amino acid within each epitope. Mutational analysis of the epitopes indicated that charged amino acids (aspartic acid, glutamic acid, and lysine) and some hydrophobic (leucine, phenylalanine, and glycine) and polar (serine, threonine, tyrosine, and cystein) amino acids were important for antibody binding. These results provide useful information for the molecular design necessary to reduce the allergenicity of ovomucoid, and a better understanding of structure-function relationships of allergic epitopes in food proteins.

Amino Acid Sequence↗

PubMed1998

The Amino Acid Composition of Anopheles stephensi (Diptera: Culicidae) Infected with Nosema algerae (Microsporida: Nosematidae)

The amino acid composition of larvae, pupae, and adult mosquitoes of Anopheles stephensi infected with Nosema algerae and noninfected insects was analyzed using an amino acid analyzer. The increase and decrease in the concentration of single amino acids during the development of the microsporidium were compared with the spread of meronts, sporonts, and spores within the host. The appearance of meronts and sporonts coincided mainly with an increase in the concentration of alanine and histidine. The amount of alanine, proline, and tyrosine decreased during spore formation. Tyrosine appeared in the hemolymph of infected A. stephensi, whereas this amino acid could not be found in the blood of uninfected insects. The spores themselves contained predominantly the glycogenic amino acid alanine, glutamic acid, aspartic acid, serine, and glycine. Proline, methionine, or tyrosine could not be detected within the spores. Copyright 1998 Academic Press. Copyright 1998 Academic Press

Journal Article↗

PubMed1991

Small acidic peptides are bound to E. coli DNA.

Low molecular weight peptides have been isolated by alkali extraction from deproteinized DNA of E. coli cells grown in the presence of radioactive glutamic acid or orthophosphate. The labeled peptides, purified by gel filtration chromatography on Sephadex G25 and G10, contain prevailingly glutamic acid, aspartic acid, glycine, serine and alanine. Electrophoretic studies at different pH show that some peptide fractions contain a phosphoric residue. The N-terminus of the phosphorylated peptides is apparently blocked and they were able to bind to DNA in the presence of Mg2+ ions. Moreover the acidic peptides extracted from E. coli DNA show a sharp activity in the control of lambda phage DNA transcription 'in vitro'.

Amino Acids↗

PubMed1977

[Modification of relative amount of free amino acids in the stratum corneum of human epidermis by special factors of the environment. I. The influence of UV-irradiation (author's transl)].

By repeated uv-irradiation the quantity of all free amino acids (per surface unit) in human horny layer increase considerably. 4 different groups of substances are found by taking the relative values in mole per cent. 1. No difference for urea, threonine, serine, glutamine, tyrosine and ammonia. 2. Decrease of about 20 p.c. for glutaminic acid, citrulline, arginine, histidine. 3. Increase of about 20 p.c. for urocanic acid, aspartic acid, proline, glycine, valine, isoleucine. 4. The rest of amino acids increase about 30--50 p.c.

Amino Acids↗

PubMed1979

Characterization of a 130,000-dalton glycoprotein isolated from pulmonary secretions of patients with alveolar proteinosis.

A new glycoprotein with an apparent molecular weight of 130,000 was isolated, purified, and partially characterized from the pulmonary secretions which accumulate so massively in the lungs of patients suffering from pulmonary alveolar proteinosis. The amino acid analysis of the glycoprotein showed the presence of relatively high amounts of glycine, glutamic acid, aspartic acid, leucine, and valine, and small amounts of hydroxyproline, but no hydroxylysine. It contains approximately 6% hexose, 3% sialic acid, and 4% glucosamine. The neutral sugars are galactose, mannose, and fucose. This alveolar glycoprotein cross-reacted with an antiserum prepared in rabbits against a larger glycoprotein (250,000 mol wt) isolated from the same source, suggesting that the larger alveolar glycoprotein may be the precursor of the smaller one.

Amino Acid Sequence↗

PubMed1986

Taurine and other free amino acids in the retina, vitreous, lens, iris-ciliary body, and cornea of the rat eye.

Levels of free amino acids were determined quantitatively in whole ocular tissues of the rat eye with aid of a sensitive amino acid analyzer. The tissues studied were the retina, vitreous, lens, iris-ciliary body, and cornea. The retina and lens contained a more concentrated free amino acid pool than other tissues. The neuroactive amino acids taurine. GABA, glutamic acid, aspartic acid, and glycine were clearly enriched in the retina. Taurine was the most abundant amino acid in all five tissues studied, and its high concentration in non-neural tissues, especially the lens, suggests that it must have other functions as well as neurotransmitter ones in the rat eye.

Amino Acids↗

PubMed1982

Cysteine-induced effect on amino acids in neonatal rat brain.

In neonatal rat brain 6 h after s.c. administration of L-cysteine, an increase was observed in most of the amino acids with the exception of glutamic acid, aspartic acid, phenylalanine, sarcosine, glutamine, hydroxyproline and phosphoethanolamine compared to age-matched saline controls. Cysteine was not present at detectable levels in control brain but was found to be 0.38 to 0.52 mumole/g of fresh brain tissue in 2- and 4-day-old rats respectively after cysteine treatment.

Aging↗

PubMed1979

[Isolation and characterization of a new placenta specific protein (PP10) (author's transl)].

PP10 was isolated from aqueous extracts of human term placentae by fractionating the proteins with rivanol and ammonium sulfate, by gelfiltration on Sephadex G-150 and by use of immunoadsorbents. PP10 apparently is a protein specific for the placenta; it could not be detected in extracts from other human tissues. From one human term placenta an average amount of 20 mg PP10 can be extracted. In sera from pregnant women PP10 is usually present only in trace amounts (less than 0.1 mg/100 ml). PP10 has the electrophoretic mobility of an alpha1-globulin and an isoelectric point of 5.1. The purified protein sediments with 3.8 S. PP10 was found to have a molecular weight of 48,000 as determined by ultracentrifugation and a molecular weight of 65,000 as determined by SDS-PAA gel electrophoresis. PP10 is a glycoprotein containing 6.65% carbohydrates (hexoses 4.8%, hexosamines 1.2%, fucose 0.05%, sialic acid 0.6%). The amino acid composition of PP10 has been determined, too; the most abundant amino acids in this protein are glutamic acid, aspartic acid, leucine and alanine.

Electrophoresis↗

PubMed1992

Nutritional and chemical evaluation of raw seeds of Canavalia gladiata (Jacq) DC. and C. ensiformis DC: the under utilized food and fodder crops in India.

In India, the seeds of Canavalia gladiata and C. ensiformis have traditionally been eaten by the aborigines, but they are less popular among the civilized people. The data on the chemical composition and nutritional quality of these seeds are not readily available. The proximate composition, mineral composition, the contents of total (true) proteins, seed protein fractions, profile of seed protein amino acids and certain antinutritional factors were analysed and reported in the present study. The seeds of C. ensiformis contain more crude protein, crude lipid and minerals like Na, K, Ca, Mg, P, Fe and Mn than does C. gladiata. Both albumins and globulins together constitute the major bulk of seed proteins. In both the species of Canavalia investigated, glutamic acid, aspartic acid, isoleucine + leucine, tyrosine + phenylalanine and lysine are the major amino acids of seed proteins. The presence of certain antinutritional factors (total free phenols, tannins, lectins, L-DOPA, trypsin inhibitor activity) is also reported for both species of Canavalia.

Albumins↗

PubMed1988

Lipids of dermatophytes. III. Sterol-induced changes in the lipid composition and functional properties of Epidermophyton floccosum.

Sterol supplementation, alone or in the presence of cerulenin, resulted in an increase in the total sterol content of Epidermophyton floccosum. While the total phospholipid levels of E. floccosum exhibited only marginal changes with sterol supplementation, the fatty acid profiles of these phospholipids were highly varied. In the presence or absence of cerulenin, the oleic acid content of phospholipids were increased significantly by cholesterol supplementation, whereas linoleic acid levels were enhanced by ergosterol supplementation. These variations resulted in higher unsaturated/saturated phospholipid fatty acid ratios in sterol-supplemented cells. The uptake of labeled amino acids (aspartic acid, lysine, glycine) was influenced by sterol supplementation. Alterations in the number of binding sites for the membrane probe, 1-anilino-naphthalene-8-sulfonate (ANS), were seen based on Scatchard plot calculations. The results indicate a correlation between sterol-induced changes in membrane lipid composition and function.

Amino Acids↗

PubMed1975

Heterogeneous elevation of amino acid transport rates in pantothenate-and lipid-deficient Lactobacillus plantarum.

The effect of a pantothenic acid deficiency in Lactobacillus plantarum on the initial rate of amino acid transport was investigated. Although the steady-state accumulation capacity for all amino acids was markedly reduced in pantothenate-deficient cells, initial rates of uptake either were not changed (asparagine, alanine, lysine) or were increased (glutamic acid, aspartic acid leucine). The findings suggest that a reduction in membrane lipid content heterogeneously affects the operation and/or synthesis of amino acid transport catalysts.

Amino Acids↗

PubMed1979

Isolation and partial characterization of intermediate filament protein (skeletin) from cow heart Purkinje fibres.

The intermediate filament protein skeletin from cow heart Purkinje fibres was purified to homogeneity by a selective extraction procedure and gel chromatography in the presence of sodium dodecyl sulphate. Monospecific antibodies were obtained by immunisation of rabbits with the sodium dodecyl sulphate-skeletin complex, and rocket electrophoresis made it possible to quantify the concentration of protein. The skeletin monomer has a molecular weight of 55 000. Amino acid analysis revealed that skeletin has a high content of glutamic acid, aspartic acid, alanine and leucine, together constituting more than 50% of the molecule. The isoelectric point is determined as 6.35. Skeletin is insoluble at pH 4--6 in the absence of detergent and shows increasing solubility at higher and lower pH. The biochemical characteristics are discussed in relation to the cytoskeletal function of the filaments. Comparison with intermediate-sized filament protein of other tissues show certain important similarities suggesting that the filaments may share a common evolutionary ancestry.

Amino Acids↗

PubMed1980

Biochemical properties of tissue polypeptide antigen.

Tissue polypeptide antigen (TPA) is a complex protein which has been originally identified in extracts of pooled tumors using horse antisera raised against the insolubles of human tumor cells. The antigen is now routinely detected and measured by a previously described hemagglutination inhibition assay. It has been shown by this method that the concentration of the antigen is higher in tumor tissues and in sera of cancer patients as compared to normal tissues or normal sera, respectively. In aqueous solutions, pH 2-12, TPA has a tendency to form high molecular weight aggregates. However they can be dissociated in sodium dodecyl sulfate into subunits, each appearing as a single chain peptide: B1 (Mr 4.3 x 10(4)), B2 (Mr 3.0 x 10(4)), C (Mr 1.7 x 10(4)). The subunits saturate anti-TPA serum indistinguishably from TPA. Amino acid composition of TPA and subunits is dominated by glutamic acid, aspartic acid and leucine, cysteine being absent in subunit B1. The isoelectric point of the main subunit, B1, is 4.4-4.6. Sedimentation and diffusion analyses indicate that pure subunit B1 in aqueous solution exists in distinct oligomeric states.

Amino Acids↗

PubMed1985

Changes in elastin composition in aorta of spontaneously hypertensive rats (SHR).

Tropoelastin and elastin preparations obtained from aortae of spontaneously hypertensive rats (SHR) show an increased proportion of polar amino acids (aspartic acid, glutamic acid, arginine and tyrosine). The content of these amino acids is 1.43-3.04 times higher in SHR rats than in similar elastin or tropoelastin preparations obtained from normotensive animals. On the other hand elastin and tropoelastin preparations obtained from SHR rats show a lower frequency of the Val-Pro sequence; this was found to be 35.93 per 1000 amino acid residues in SHR rats as compared to 51.04 per 1000 amino acids in the preparations obtained from control animals. Since similar differences were found not only in elastin preparations but also in tropoelastin, contamination of these preparations with an acidic protein seems unlikely. In general the results obtained are similar to those seen in animals kept on a long term high fat diet. It appears feasible to suggest that these differences are caused by a changed proportion of two different elastin type.

Amino Acids↗

PubMed1989

gamma-Aminobutyric acid uptake and localization in bovine chromaffin cells in primary culture.

gamma-Aminobutyric acid (GABA) uptake was studied in bovine chromaffin cells maintained in primary culture. Uptake was found to be dependent on Na+, but not on K+ and Ca2+ ions; it was found that 2 Na+ ions were necessary for each molecule of GABA transported. 2,4-Dinitrophenol, ouabain and vanadate inhibited GABA uptake showing the energy dependency of the system. Two affinity sites were demonstrated, a high affinity site and a low affinity site with Km values of 10 microM and 170 microM, respectively. While the low affinity site did not show large variations with culture age, the Km of the high affinity site increased from 1 microM in freshly isolated cells to 10 microM in 3-9 day-old cells. GABA uptake was unaffected by glutamic acid, aspartic acid, glycine and catecholamines, while taurine, beta-alanine, nipecotic acid and L-2,4 diaminobutyric acid inhibited GABA uptake. Nipecotic acid and L-2,4 diaminobutyric acid acted as competitive inhibitors modifying Km values of the high affinity site. Subcellular studies performed on [3H]GABA-loaded chromaffin cells showed that GABA was not in secretory granules but was recovered in the 100,000 g soluble fraction. The GABA uptake process associated with chromaffin cells may be an important mechanism for regulating the modulation of catecholamine secretion. In addition, the presence of GABA in the cytosol indicates that this molecule may be an effector of chromaffin cell activity in addition to modulating catecholamine secretion.

Adrenal Medulla↗