Competitive amino acid transport between L-tryptophan and other amino acids in Schizophyllum commune

In our study on nutritional requirement for the hyphal growth of Schizophyllum commune, we found that a Trp- mutant could not grow in the L-Trp-supplied medium in the presence of L-Ser. Further growth studies showed that not only L-Ser but also as many as 11 kinds of amino acid including L-Ala, L-Arg, L-Asn, L-His, L-Leu, L-Met, L-Phe, L-Ser, L-Thr, L-Tyr and L-Val inhibited the growth of the Trp- mutant in the L-Trp-supplied medium. However, these amino acids did not inhibit the growth of a Trp+ strain. The inhibition of growth of Trp+ strain induced by a Trp analogue of 5-fluoro-DL-tryptophan (5FT), which was usually recovered by L-Trp, was rescued by the same amino acids mentioned above. The exceptions were Gly and L-Ile, which also recovered the growth inhibition induced by 5FT. These results indicate that the permease responsible for the Trp transport in S. commune might also be active to other amino acids. However, it is considered that the permease shows high affinity to L-Trp and low affinity to other amino acids. As a result, the transport of L-Trp and 5FT may be counteracted by other amino acids.     

Separation of immunoglobulin and transferrin from blood serum and plasma by metal chelate interaction chromatography

Metal chelate interaction chromatography was used to separate Ig, transferrin, and albumin from blood serum and blood plasma. A column was packed with iminodiacetic acid: 1,4-butanediol diglycidyl Sepharose 6B or Sephacryl S-300 and loaded with copper, zinc, nickel, or cobalt ion. Radial immunodiffusion assay indicated that Ig-rich fractions of blood serum obtained from Zn-, Ni-, Co-, and Cu-loaded columns contained 23.2, 81.3, 79.4, and 98.1% active IgG, respectively. Transferrin was recovered from the second peak. When the same conditions of metal chelate interaction chromatography were used for blood plasma, hemoglobin tended to bind strongly to the Cu-loaded column and was eluted only with 50% ethanol. Modification of histidine residues in Ig and transferrin with diethyl pyrocarbonate almost completely destroyed their binding ability to the column. Immunoglobulin G separated showed antilipopolysaccharide antibody activity against Escherichia coli, Salmonella typhimurium, and Bordettella parapertussis.     

In situ X-ray analysis of mechanism of nonlinear super elastic behavior of Ti–Nb–Ta–Zr system beta-type titanium alloy for biomedical applications

Ti–XNb–10Ta–5Zr (mass %) alloys based on nominal compositions of Ti–35Nb–10Ta–5Zr, Ti–30Nb–10Ta–5Zr, and Ti–25Nb–10Ta–5Zr were fabricated through powder metallurgy and forging and swaging processes for biomedical applications. The tensile deformation mechanisms of the Ti–25Nb–10Ta–5Zr, Ti–30Nb–10Ta–5Zr, and Ti–35Nb–10Ta–5Zr alloys were investigated in situ by X-ray diffraction analysis under several loading conditions.Under the loading conditions, the X-ray diffraction peaks of all the specimens shifted to higher angles than those obtained under the unloading conditions. For the Ti–30Nb–10Ta–5Zr alloy, the elastic deformation is considered to progress continuously in a different crystal direction although after the elastic strain reaches elastic limit in the crystal direction where the elastic limit is the smallest, slip deformation occurs in that crystal direction. The elastic modulus of this alloy appears to decrease in terms of strain over the proportional limit. Thus, the elastic deformation behavior of the Ti–30Nb–10Ta–5Zr alloy does not obey Hooke's law.     

Serologic study of the working mechanisms of immunotherapy for children with perennial allergic rhinitis

BACKGROUND: Recent double-blind placebo-controlled trials have clearly shown the efficacy of immunotherapy for perennial allergic rhinitis. However, the exact working mechanisms related to the clinical effect of immunotherapy remain unclear. OBJECTIVES: To monitor the changes over time in immunologic parameters in children who received immunotherapy for perennial allergic rhinitis, and to elucidate the working mechanisms of immunotherapy related to its clinical efficacy. DESIGN: Nineteen children with perennial allergic rhinitis due to Dermatophagoides farinae enrolled in this prospective open study. Venous blood was collected to determine levels of specific IgE, specific IgG4, soluble interleukin 2 receptor, interleukin 4, soluble intercellular adhesion molecule 1, and soluble vascular cell adhesion molecule 1 at enrollment and 1, 2, 3, 5, and 10 years after enrollment. RESULTS: Immunotherapy affected serum levels of specific IgE, specific IgG4, soluble interleukin 2 receptor, interleukin 4, and soluble intercellular adhesion molecule 1, but not soluble vascular cell adhesion molecule 1. The rates of increase of levels of specific IgG4 and the rates of decrease of levels of soluble interleukin 2 receptor were correlated with the rates of decrease of symptom scores during the first 3 years of treatment, but not after 5 years. The rates of decrease in levels of soluble intercellular adhesion molecule 1 were correlated with the rates of decrease in symptom scores at 3 and 5 years after the beginning of the course of immunotherapy. The rates of decrease in levels of specific IgE and interleukin 4 were correlated with the rates of decrease in symptom scores after 5 and 10 years of treatment, but not during the first 3 years. CONCLUSION: Each modulation in levels of specific IgE, specific IgG4, soluble interleukin 2 receptor, interleukin 4, and soluble intercellular adhesion molecule 1 contributed to the clinical effect of immunotherapy in particular phases of treatment for children with perennial allergic rhinitis.     

Beta-endorphinergic innervation of mu and delta receptor containing neurons in the dorsal raphe nucleus

A pre-embedding double immunostaining technique was used to determine the role of beta-endorphin in synapse, particularly in neurons with a postsynaptic membrane containing micro-1 or delta-1 opioid receptors. A small number of beta-endorphin immunoreactive axon terminals in the dorsal raphe nucleus was found to make direct synapses on micro-1 or delta-1 opioid receptor-immunoreactive dendrites, some of which showed immunostaining of their postsynaptic membranes, although with low frequencies. These results suggest that beta-endorphin can play a direct role through the micro-1 or delta-1 opioid receptors at synapses, but the main route would be through other opioid receptor at the synapse or even not through the synapse.     

Stress Corrosion and Corrosion Fatigue Crack Growth of Zr-Based Bulk Metallic Glass in Aqueous Solutions

Crack-propagation tests on a bulk metallic glass (BMG), Zr₅₅Cu₃₀Ni₅Al₁₀, were conducted either in aqueous sodium chloride (NaCl) solutions or in high-purity water under sinusoidal cyclic loading or sustained loading. Although the crack growth rate in high-purity water was almost identical to that in air, the rate in the NaCl solution was much higher than that in air, even in a very low concentration of NaCl such as 0.01 mass pct. In a 3.5 mass pct NaCl solution, the time-based crack growth rate during cyclic loading, da/dt, was determined by the maximum stress-intensity factor, K _max, but was almost independent of the loading frequency and the stress ratio, and the rate was close to that of stress corrosion cracking (SCC) under a sustained loading.     

Intrinsic nature of the three-dimensional structure of proteins as determined by distance geometry with good sampling properties

A protocol for distance geometry calculation is shown to have excellent sampling properties in the determination of three-dimensional structures of proteins from nuclear magnetic resonance (NMR) data. This protocol uses a simulated annealing optimization employing mass-weighted molecular dynamics in four-dimensional space (Havel, T.F. (1991) Prog. Biophys. Mol. Biol., 56, 43-78). It attains an extremely large radius of convergence, allowing a random coil conformation to be used as the initial estimate for the succeeding optimization process. Computations are performed with four systems of simulated distance data as tests of the protocol, using an unconstrained L-alanine 30mer and three different types of proteins, bovine pancreatic trypsin inhibitor, the alpha-amylase inhibitor Tendamistat, and the N-terminal domain of the 434-repressor. The test of the unconstrained polypeptide confirms that the sampled conformational space is that of the statistical random coil. In the larger and more complicated systems of the three proteins, the protocol gives complete convergence of the optimization without any trace of initial structure dependence. As a result of an exhaustive conformational sampling by the protocol, the intrinsic nature of the structures generated with distance restraints derived from NMR data has been revealed. When the sampled structures are compared with the corresponding X-ray structures, we find that the averages of the sampled structures always show a certain pattern of discrepancy from the X-ray structure. This discrepancy is due to the short distance nature of the distance restraints, and correlates with the characteristic shape of the protein molecule.     

Comparison of four purification methods for the production of immunoglobulins from eggs laid by hens immunized with an enterotoxigenic E. coli strain

Calpain and its endogenous inhibitor, calpastatin, were isolated from erythrocytes of various mammals and their properties were compared. It has been widely believed that mammalian erythrocytes contain only mu-calpain. However, rat and human erythrocytes were found to contain two species of calpain, identified as mu-calpain and m-calpain from their elution positions on DEAE-cellulose column chromatography and their Ca(2+)-requirements. Thus, it is apparent that rat and human erythrocytes contain not only mu-calpain, but m-calpain as well. On the other hand, rabbit erythrocytes contain only mu-calpain. Western blot analysis showed that human and rabbit erythrocytes contain predominantly 70-kDa calpastatin (erythrocyte-type), but unnegligible amounts of 110-kDa calpastatin (tissue-type) are also present. Rat erythrocytes were shown to contain a calpastatin with a molecular mass of approx. 100 kDa almost exclusively; this molecular mass was in perfect coincidence with the mass of the calpastatin in rat lung. These results strongly suggest that rat erythrocytes contain a tissue-type calpastatin. No essential change in the calpain/calpastatin system during maturation of rabbit reticulocytes into mature erythrocytes was observed.     

Regulation of 18-oxocortisol and 18-hydroxycortisol by the renin-angiotensin system and ACTH in man

Based on urinary excretion studies the secretion of the cortisol derivatives, 18-oxocortisol and 18-hydroxycortisol are believed to be regulated by ACTH and to a lesser degree by the renin-angiotensin system. Plasma concentrations of 18-oxocortisol and 18-hydroxycortisol were measured during the simultaneous activation of the renin-angiotensin system and inhibition of ACTH secretion. Five healthy male subjects consuming a sodium diet ad libitum were studied. Blood was drawn at 0800 h after 1 h in the supine position. In the first set of experiments, the subjects remained in the supine position from 0800 to 1000 h with or without the oral administration of 2 mg dexamethasone at 0800 h. In the second set of experiments the subjects were placed in the upright position after drawing the 0800 h sample. The subjects were studied with and without dexamethasone administered at 0800 h. Blood was drawn again at 1000 h. Plasma levels of 18-oxocortisol, 18-hydroxycortisol, ACTH, plasma renin activity (PRA), cortisol, aldosterone and 18-hydroxycorticosterone were measured by radioimmunoassay. None of these parameters changed during the 2 h in the supine position. 18-Oxocortisol, 18-hydroxycortisol, aldosterone, 18-hydroxycorticosterone and PRA increased, but ACTH and cortisol did not change when the subjects were placed in the upright position. After dexamethasone administration, 18-oxocortisol, 18-hydroxycortisol, cortisol, aldosterone and 18-hydroxycorticosterone decreased in the supine position and no increase occurred in 18-oxocortisol, 18-hydroxycortisol and 18-hydroxycorticosterone in the upright position. PRA and aldosterone increased and ACTH and cortisol decreased in these subjects. 18-Oxocortisol and 18-hydroxycortisol were more dependent on ACTH regulation and less on the renin-angiotensin system than aldosterone.     

Acceleration or Suppression of α-Phase Precipitation Using Isothermal ω Phase in Ti-20 at.pct Nb Alloy

Homogeneous precipitation of a fine α phase in the β matrix of Ti alloys is a promising method for obtaining a highly strengthened Ti-based alloy. Isothermal ω particles are known to be the nucleation sites for fine α-phase precipitation, but an understanding of the kinetics of α-phase formation on isothermal ω particles is still lacking. This study aimed to reveal the effect of isothermal ω particles on α-phase precipitation onset time. Two-step isothermal aging of a Ti-20 at.pct Nb alloy after solid solution treatment at 1273 K (1000 °C) was carried out. The first step of the aging at 633 K (360 °C) involved the formation of isothermal ω particles in the β matrix. This was followed by a second aging step at 673 K, 723 K, and 773 K (400 °C, 450 °C, and 500 °C) for α-phase precipitation. Suppression of α-phase nucleation on the isothermal ω particles occurred at 673 K (400 °C), whereas acceleration of α-phase nucleation on the isothermal ω particles was observed at 723 K and 773 K (450 °C and 500 °C). Thermodynamic stability of the isothermal ω particles and solute partitioning were controlling factors for the α-phase precipitation kinetics.