Effect Of L-phenylalanine Research Articles

Development of an Efficient Strategy to Improve Extracellular Polysaccharide Production of Ganoderma lucidum Using L-Phenylalanine as an Enhancer.

Ganoderma lucidum has been a well-known species of basidiomycetes for a long time, and has been widely applied in the fields of food and medicine. Based on the simulation results of model iZBM1060 in our previous research, the effect of L-phenylalanine on G. lucidum extracellular polysaccharides (EPSs) was investigated in this study. EPS production reached 0.91 g/L at 0.4 g/L L-phenylalanine after a 24 h culture, which was 62.5% higher than that of control (0.56 g/L). Transcriptome and genome analysis showed that L-phenylalanine deaminase and benzoate 4-hydroxylase (related to L-phenylalanine metabolism) were significantly up-regulated, while the cell wall mannoprotein gene was down-regulated. Transmission electronic microscopy (TEM) and atomic force microscopy results showed that the cell wall thickness decreased by 58.58%, and cell wall porosity increased in cells treated with L-phenylalanine, which probably contribute to the increasing EPS production. This study provides an efficient strategy for fungal polysaccharide production with high output and low cost.

Effect of l-phenylalanine on PAL activity and production of naphthoquinone pigments in suspension cultures of Arnebia euchroma (Royle) Johnst

The effects of l-phenylalanine (PHE) on cell growth and production of shikonin and its derivatives, acetylshikonin (ACS) and isobutyrylshikonin (IBS), in suspension cultures of Arnebia euchroma were examined. Supplementing media using PHE have been successfully utilized to enhance shikonin production in cell cultures of other species of Boraginaceae. l-Phenylalanine, the key compound in the phenylpropanoid pathway, is converted by phenylalanine ammonia lyase (PAL) to trans-cinnamic acid, which is the precursor of p-hydroxybenzoic acid (PHB). Coupling of PHB and geranyl pyrophosphate (derived from mevalonate pathway) by p-hydroxybenzoate-m-geranyltransferase leads later to biosynthesis of shikonins. The addition of 0.01 or 0.1 mM PHE to the culture medium stimulated cell proliferation, where the highest observed increase in fresh cell biomass (measured as a ratio of final weight to initial weight) was 12-fold, in contrast to an eightfold increase in control cultures. Whereas, growth media supplemented with 1 mM PHE markedly reduced the rate of cell growth (to only twofold). Precursor feeding had detrimental effects on both ACS and IBS production in all PHE-supplemented media. The highest total content (intracellular + extracellular) of the investigated red pigments (9.5 mg per flask) was detected in the control culture without PHE. ACS was the major component of the naphthoquinone fraction determined in cells and post-culture media. Shikonin itself was found only in the post-culture media from cultures supplemented with 0.01 or 0.1 mM PHE. Increases in PAL activity corresponded well with the accumulation of investigated naphthoquinones in control culture. However, peak PAL activity did not directly correlate with maximum production of shikonin derivatives. Cytotoxicity of extracts, prepared from the cells cultivated in the presence of PHE or in control cultures, was tested on three cancer cell lines: HL-60, HeLa, and MCF-7. The extracts prepared from the untreated control cultures proved to be the most potent against the examined cancer cell lines. The mean inhibitory concentration values were 0.3, 13, and 8 μg ml−1 for the HL-60, HeLa, and MCF-7 cells, respectively.

Controlling factor of polymorphism in crystallization process

The controlling factor and mechanism of the crystallization of polymorphs were investigated in the various systems. The effect of supersaturation was hardly observed in the polymorphic crystallization of both L-glutamic ( α, β) and L-histidine (A,B). The temperature effect appeared intensively in the case of L-glutamic acid polymorphs, however, no effect of temperature was observed for L-histidine polymorphs. Such difference of the temperature effect may be related with the difference of the molecular conformation between the polymorphs. In the reactive crystallization of calcium carbonate polymorphs between the calcium chloride and the sodium carbonate solutions, the effect of the concentration (supersaturation) of reactant solutions, the mixing rate of the solutions and temperature on the morphology and the crystallization of polymorphs (calcite, vaterite and aragonite) was observed. The complicated precipitation behavior and the morphological change may be related with the formation of the precursors. The effect of L-phenylalanine on the growth rate and morphology of L-glutamic acid polymorphs was also investigated by the single crystal method. The relationship between the additive concentration and the growth rate of each polymorphs was presented by the equation of the proposed model. The method of the selective crystallization of the polymorphs by controlling the supersaturation degree and the additive concentration was also indicated.

Effects of l-phenylalanine on acetylcholinesterase and Na +, K +-ATPase activities in adult and aged rat brain

The effect of different l-phenylalanine (Phe) concentrations (0.12–1.8 mM) on acetylcholinesterase (AChE), (Na +, K +)-ATPase and Mg 2+-ATPase activities was investigated in homogenates of adult and aged rat whole brain at 37°C. Adult and aged rat experiments were necessary in relation to phenylketonuria (PKU) since phenylketonuric patients usually discontinue their therapeutic special diet when they reach adulthood. Diet discontinuation results in the pathological increase of Phe concentration in plasma and consequently in brain. AChE activity in adult brain homogenates showed a decrease up to 18% ( P<0.01) with 0.48–1.8 mM Phe preincubated for 1 h. Adult brain Na +, K +-ATPase was stimulated by 30–35% ( P<0.01) in the presence of 0.48–1.8 mM Phe. However, high Phe concentrations were not able to affect the activities of AChE and Na +, K +-ATPase, when preincubated with aged brain homogenate for 3 h. Moreover, high Phe concentrations appeared unable to affect the activity of eel E. electricus pure AChE inhibited about 30% ( P<0.001) by the free radical system H 2O 2/Fe 2+. Also, the antagonists of α- and β-adrenergic receptors (phenoxybenzamine and propranolol, respectively) inhibited adult rat brain Na +, K +-ATPase activity about 30–40% ( P<0.01) and Phe was unable to change this action. It is suggested that: (a) The inhibitory effect of Phe on brain AChE and its stimulatory effect on brain Na +, K +-ATPase are decreased with age; (b) These effects may be influenced by aging factors, such as free radical action and/or reduced density of α- and β-adrenergic receptors in the tissue.

Building Fluorescent Sensors by Template Polymerization: The Preparation of a Fluorescent Sensor for [formula omitted]-Tryptophan

The development of fluorescent sensors for organic molecules is of great practical importance in chemical, biological, and pharmaceutical sciences. Using l-tryptophan as an example, we have studied a new way of making polymeric fluorescent sensors using template polymerization or molecular imprinting techniques. The fluorescent polymers were prepared using functional monomers with a fluorescent probe attached to it. The fluorescence of this polymer could be quenched by 4-nitrobenzaldehyde. Addition of the template molecules, l-tryptophan, increased the fluorescence intensity of the imprinted polymer/quencher mixture in a concentration-dependent fashion, presumably through the displacement of the quencher from the binding sites by l-tryptophan. This fluorescence intensity change upon mixing with l-tryptophan allows the binding event to be detected easily. The sensor also exhibited enantioselectivity for the template molecules. For example, the effect of d-tryptophan on the fluorescence intensity of the polymer is about 70% that of its l-enantiomer. Furthermore, the effect of l-phenylalanine and l-alanine on the fluorescence intensity change is much smaller than that of l-tryptophan. Because the approach used does not require the de novo design of the complementary binding site and does not rely on any specific structural features of the template molecule or prior knowledge of its three-dimensional structure, the same principle could potentially be useful for the future construction of practical fluorescent sensors for many other compounds.

Effect of l-Phenylalanine on Rooting of Shoots from Axillary Buds of Adult Larix Leptolepis

Rooting of shoots derived from axillary buds was examined to establish an efficient shoot culture system of clonal micropropagation in adult tree of Larix leptolepis Gord. (Japanese larch). Nine out of ten shoots induced calli (90%) on their shoot bases, and the two of them formed root primordia with a red pigment (20%) on the calli surface within 5 weeks after culturing on modified Murashige and Skoog (MS) medium supplemented with 1.5 μM of indolebutyric acid (IBA) and 1.5 μM of naphthaleneacetic acid (NAA). However, the primordia did not elongate actively. The addition of 10 mMl-phenylalanine in the MS medium with the auxins resulted in the formation of roots at high frequency, about 80%, and they elongated actively. Although callus was formed in all the shoots cultured on the medium withl-phenylalanine, it appeared that the callus development was less as compared to the medium withoutl-phenylalanine. Consequently, the rooting might be associated with the suppression of the induced callus.

Some considerations of the SERS effect ofL-phenylalanine in the near-infrared region using silver colloid solution

The surface-enhanced Raman scattering (SERS) spectra of L-phenylalanine were examined in the near-infrared region using silver colloid solutions. It was shown that near-infrared SERS (NIR-SERS) was not detected for L-phenylalanine in a normal silver colloid solution, whereas in the visible region a distinct SERS intensity enhancement was realized for such sample systems. In the present study, this situation was considered from the viewpoint that the degree of aggregation of colloid particles necessary to cause the SERS effect is different between visible and near-infrared radiation. In this work, silver colloid solution containing dissolved L-phenylalanine was dropped on to a filter-paper and this filter-paper sample was then dried. It was confirmed by SEM (scanning electron microscopy) that as a result of this sample preparation, the degree of aggregation of colloid particles increased considerably. It was shown that the near-infrared SERS was detected with high sensitivity for L-phenylalanine adsorbed on silver particles condensed on filter-paper. From consideration of the magnitudes of the SERS intensity enhancement in this case, it is suggested that the mechanism of NIR-SERS for the present sample system is the electromagnetic effect, related to the excitation of surface plasmons (the surface plasmon polariton mechanism). © 1997 John Wiley & Sons, Ltd.

Effect of Hyperphenylalaninemia Chemically Induced onin VitroIncorporation of32P into Cytoskeletal Proteins from Cerebral Cortex of Developing Rats

We studied the effect of hyperphenylalaninemia onin vitroincorporation of32P into cytoskeletal proteins from cerebral cortex of rats by injectingl-phenylalanine plus α-methylphenylalanine subcutaneously from the 6th to the 14th day postpartum. Chronic hyperphenylalaninemia induced an increasedin vitrophosphorylation of the 150-kDa neurofilament subunit and tubulins present in the cytoskeletal fraction at the end of the treatment and 3 days after treatment discontinuation. In addition, whenin vitrophosphorylation of the cytoskeletal proteins from treated animals was performed in the presence of the drugs we observed a decreasedin vitroincorporation of32P into these proteins. Thus, the effect ofl-phenylalanine plus α-methylphenylalanine on the endogenous protein kinase and phosphatase activities was examined and the results demonstrated that these drugs have an inhibitory effect on calcium/calmodulin-dependent protein kinase II and protein phosphatase type 1.

Morphology Change in Crystallization of α L-Glutamic Acid in the Presence of L-Phenylalanine

Abstract Effect of L-phenylalanine(L-Phen) on the precipitation behavior and morphology of a L-glutamic acid (L-Glu) crystals, and inclusion of L-Phen in L-Glu crystals were investigated. L-Phen suppresses both nucleation rate and growth rate of L-Glu. The morphology of L-Glu was observed to change depending on L-Phen concentration. Two predominant morphologies were obtained, which have the large (111) face and the new face of (110), respectively. Irregular increase of the molar ratio of L-Phen to L-Glu in nucleated crystals was detected and it was attributed to the morphology change of L-Glu crystals. Dependence of R on L-Phen concentration appeared to be different between the nucleated crystals and seed crystals.

Effect of L-phenylalanine and L-methionine on the appearance of L-tryptophan-producing mutants of Bacillus subtilis K.

Effect of L-phenylalanine and L-methionine on the appearance of L-tryptophan-producing mutants of Bacillus subtilis K.

The role of phosphoenolpyruvate in insulin secretion: the effect of L-phenylalanine.

Incubation of rat islets with phenylalanine increased the tissue content of phosophoenolpyruvate, both in the presence and in the absence of glucose. At the same time, L-phenylalanine neither stimulated nor inhibited insulin release. It is unlikely that insulin secretion is tightly coupled to the availability of phosphoenolpyruvate in rat islets.

Inhibition by L-phenylalanine of tyrosine transport by synaptosomal plasma membrane vesicles: implications in the pathogenesis of phenylketonuria.

The effect of L-phenylalanine on the transport of tyrosine was studied using membrane vesicles from rat brain synaptosomes. Phenylalanine, which is accumulated in phenylketonuria, competitively inhibits tyrosine uptake at concentrations similar to those found in phenylketonuric patients, with a Ki of the same order of the Km for tyrosine. This inhibition could be responsible for the depletion of catecholamines observed in phenylketonuria.

Inhibition by L-phenylalanine of tryptophan transport by synaptosomal plasma membrane vesicles: implications in the pathogenesis of phenylketonuria.

Phenylalanine is accumulated in the genetically linked deficiency phenylketonuria. The effect of L-phenylalanine on the transport of tryptophan was studied using membrane vesicles from rat-brain synaptosomes. Phenylalanine at similar concentrations to those found in phenylketonuric patients competitively inhibits tryptophan uptake, with a Ki of the same order as the Km for tryptophan. This inhibition could be responsible for the depletion of serotonin found in phenylketonuria.

The Effect of L-Phenylalanine on Phenylalanine Ammonia-lyase and Cell Division in Artichoke Callus Culture

The Effect of L-Phenylalanine on Phenylalanine Ammonia-lyase and Cell Division in Artichoke Callus Culture

Experimental phenylketonuria: Metabolic studies in rat liver

The "in vivo" effects of L-phenylalanine on the gluconeogenic pathway in the liver of fasted rats with experimentally induced phenylketonuria-like characteristics have been investigated. Significant increases of the fructose 6-phosphate, glucose 6-phosphate and glucose concentrations were observed. The study of the effect of L-phenylalanine on the cytoplasmic and mitochondrial redox state and energy charge showed an increase in the mitochondrial NAD+/NADH ratio while the energy charge was virtually unchanged. The effects of phenylalanine and its metabolic derivatives (phenylacetate, phenylethylamine, phenyl-lactate, o-hydroxyphenylacetate and phenylpyruvate) on the activity of lactate dehydrogenase (EC 1.1.1.27), malate dehydrogenase (EC 1.1.1.37) and 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) in rat liver have been also investigated. Phenylpyruvate inhibited the lactate dehydrogenase activity with a Ki of 5.3 mM. Phenylpyruvate also inhibited both the mitochondrial (Ki = 4 mM) and cytoplasmic (Ki = 5 mM) malate dehydrogenase activities. Phenylpyruvate, phenylacetate and o-hydroxyphenylacetate inhibited the 3-hydroxybutyrate dehydrogenase activity with Ki values of 0.7, 6.0 and 9.5 mM respectively.

Effect of l-phenylalanine on 1-methyladenine production and spontaneous oocyte maturation in starfish

Production of 1-methyladenine (1-MA) in isolated ovarian fragment under the influence of the gonad-stimulating substance (GSS) was found to be inhibited by treatment with phenylalanine at concentrations higher than 10 mM in the starfish, Asterina pectinifera. The so-called ‘spontaneous’ maturation of the oocytes of Asterias amurensis isolated in sea water was also inhibited in the presence of phenylalanine. 1-MA was produced in the isolated follicle cells of this species in sea water in the absence of GSS. Such production of 1-MA was greatly reduced by lack of calcium ions, corresponding to the failure of spontaneous maturation in calcium-free sea water. Production of 1-MA in the isolated follicle cells of Asterias amurensis in sea water was suppressed by phenylalanine. The so-called ‘spontaneous’ oocyte maturation observed in the genus Asterias appears to be induced by 1-MA produced in the follicle cells in the absence of GSS. Therefore, it is concluded that oocyte maturation in starfish is invariably induced by 1-MA produced in the follicle cells. Failure of oocyte maturation in the presence of phenylalanine or in calcium deficiency does not seem to be due to the failure of release of pooled 1-MA from the follicle cells but to the inhibition of its synthesis in these cells.

Leukocyte alkaline phosphatase in pregnancy. Comparison with placental phosphatase activity

The properties of placental and leukocyte alkaline phosphatase (LAP) were investigated in pregnant and nonpregnant women, by comparing their activity towards p-nitrophenyl phosphate, β-glycerophosphate, thermostability, effect of l-phenylalanine, and, electrophoretic resolution on acrylamide gel. LAP of pregnant and control women showed similar properties, differing from those of the placental enzyme. It was concluded that the increased LAP activity in pregnant women is not likely to be of placental origin.

Effect of l-phenylalanine on central nervous system elements in tissue culture.

Effect of l-phenylalanine on central nervous system elements in tissue culture.