Effects of various kinds of dietary amino acids on the hepatotoxic action of D-galactosamine in rats

The protective effects of various kinds of dietary amino acids against the hepatotoxic action of D-galactosamine (GalN) were examined. Male Wistar rats fed with 20% casein diets containing 10% or 5% amino acid for one week were injected with GalN (800 mg/kg body weight), and the serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) activities, the hepatic glycogen concentration, and the serum glucose-level were examined 20 hours after the injection. In the groups with the 10% amino acid diets, activities of AST, ALT, and LDH in serum of 10% L-glutamine (Gln), 10% L-asparagine (Asn), and 10% L-serine (Ser) groups were significantly lower than those of the control group, and in the groups with the 5% amino acid diets, those activities of 5% L-histidine (His), 5% L-tyrosine (Tyr), 5% L-lysine (Lys), and 5% L-glycine (Gly) groups were also lower than those of the control group. The concentration of liver glycogen of 10% Gln-, 10% Asn-, and 10% Ser- groups and those levels of 5% His-, 5% Tyr-, 5% Lys-, and 5% Gly-groups were also significantly higher than that of the control group. As a result, it was found that some kinds of dietary amino acid such as L-Ser, L-Asn, L-His, L-Lys, L-Tyr, and L-Gly, in addition to L-Gln were effective to protect the rats from GalN-induced injury.     

The pheromone production of female Plodia interpunctella is inhibited by tyraminergic antagonists

Several compounds were found to suppress the calling behavior and in vitro pheromone biosynthesis of the Indian meal moth, Plodia interpunctella. The compounds were screened by means of a calling-behavior bioassay with female P. interpunctella. Five derivatives with activities in the nanomolar range were identified, in order of decreasing pheromonostatic activity: 4-hydroxybenzaldehyde semicarbazone (42) > 5-(4-methoxyphenyl)-1,3-oxazole (38) > 5-[4-(tert-butyl)phenyl]-1,3-oxazole (40) > 5-(3-methoxyphenyl)-1,3-oxazole (35) > 5-(4-cyanophenyl)-1,3-oxazole (36). These compounds also showed in vitro inhibitory activity in intracellular de novo pheromone biosynthesis, as determined with isolated pheromone-gland preparations that incorporated [1-(14)C]sodium acetate in the presence of the so-called pheromone-biosynthesis-activating neuropeptide (PBAN). The non-additive effect of the inhibitor with antagonist (yohimbine) for the tyramine (TA) receptor suggests that it could be a tyraminergic antagonist. Three-dimensional (3D) computer models were built from a set of compounds. Among the common-featured models generated by the program Catalyst/HipHop, aromatic-ring (AR) and H-bond-acceptor-lipophilic (HBAl) features were considered to be essential for inhibitory activity in the calling behavior and in vitro pheromone biosynthesis. Active compounds, including yohimbine, mapped well onto all the AR and HBAl features of the hypothesis. Less-active compounds were shown to be unable to achieve an energetically favorable conformation, consistent with our 3D common-feature pharmacophore models. The present hypothesis demonstrates that calling behavior and PBAN-stimulated incorporation of radioactivity are inhibited by tyraminergic antagonists.     

Free energy calculations for the relative binding affinity between DNA and lambda-repressor

The change in the binding free energy between DNA and lambda-repressor resulting from a base substitution, thymine (T)-->deoxyuracil (abbreviated as U), was evaluated by the free energy perturbation method on the basis of molecular dynamics simulations for the DNA-lambda-repressor complex in water with all degrees of freedom and including long-range Coulomb interactions. The binding free energy change that we calculated (1.47 +/- 0.40 kcal/mol) was in good agreement with an experimental value (1.8 kcal/mol). We clarified why the small difference between T and U (CH(3) in T is replaced with H in U) caused such a significant change in the binding free energy: The substitution of CH(3) in T with H in U lowered the dissociated-state free energy level due to the gain of the hydration free energy. Furthermore, the T-->U substitution raised the free energy level in the associated state due to the loss of the favored van der Waals (vdW) interactions with the lambda-repressor amino acid residues. In other words, the amino acid residues of lambda-repressor can recognize the CH(3) in T through the vdW interactions with the CH(3). This recognition is enhanced in a water environment, because the hydrophobic CH(3) prefers the amino acid residues of lambda-repressor to water molecules.     

Clinical implications of thermal therapy in lifestyle-related diseases

Systemic thermal therapy, such as taking a warm-water bath and sauna, induces systemic vasodilation. It was found that repeated sauna therapy (60 degrees C for 15 min) improved hemodynamic parameters, clinical symptoms, cardiac function, and vascular endothelial function in patients with congestive heart failure. Vascular endothelial function is impaired in subjects with lifestyle-related diseases, such as hypertension, hyperlipidemia, diabetes mellitus, obesity, and smoking. Sauna therapy also improved endothelial dysfunction in these subjects, suggesting a preventive role for atherosclerosis. In animal experiments, sauna therapy increases mRNA and protein levels of endothelial nitric oxide synthase (eNOS) in aortas. In normal-weight patients with appetite loss, repeated sauna therapy increased plasma ghrelin concentrations and daily caloric intake and improved feeding behavior. In obese patients, the body weight and body fat significantly decreased after 2 weeks of sauna therapy without increase of plasma ghrelin concentrations. On the basis of these data, sauna therapy may be a promising therapy for patients with lifestyle-related diseases.     

Expression and function of the Ror-family receptor tyrosine kinases during development: lessons from genetic analyses of nematodes,mice, and humans

Receptor tyrosine kinases (RTKs) play crucial roles in various developmental processes. Ror-family RTKs are characterized by the intracellular tyrosine kinase domains, highly related to those of the Trk-family RTKs, and by the extracellular Frizzled-like cysteine-rich domains (CRDs) and Kringle domains. Rors are evolutionally conserved among Caenorhabditis elegans, Aplysia, Drosophila melanogaster, Xenopus, mice, and humans. In D. melanogaster and mammals, pairs of structurally related Rors are found, while a single Ror protein is identified in C. elegans or Aplysia. In Aplysia and D. melanogaster, Rors are expressed exclusively in developing nervous systems. On the other hand, rather widespread expression of Rors was observed in C. elegans and mammals. Mutations in Ror of C. elegans cause inappropriate axon outgrowth as well as defects in cell migration and asymmetric cell division. It has also been reported that the nematode Ror possesses kinase-dependent and kinase-independent functions. Mouse Rors, Ror1, and Ror2, are expressed mainly in migrating neural crest cells and mesenchymal cells, and Ror2-deficient mice exhibit skeletal abnormalities and ventricular septal defects in the heart. Although Ror1-deficient mice exhibit no apparent skeletal or cardiac abnormalities, Ror1/Ror2 double mutant mice show markedly enhanced skeletal and cardiac abnormalities compared with Ror2 mutant mice, indicating genetic interaction of Ror1 and Ror2. In humans, mutations within Ror2 have been found in two genetic skeletal disorders, recessive Robinow syndrome and dominant Brachydactyly type B (BDB), further emphasizing critical functions of Ror2 during developmental morphogenesis. In this article, we also discuss the signaling machinery mediated by Ror-family RTKs with a particular emphasis on our recent structure-function analyses of Ror-family RTKs.     

The dual functions of biphenyl-degrading ability of Pseudomonas sp. KKS102: energy acquisition and substrate detoxification

The bph operon of Pseudomonas sp. KKS102 is constituted of 11 bph genes which encode enzymes for biphenyl assimilation. Growth of a mutant in which a large part of the bph operon was deleted was inhibited by biphenyl in a concentration-dependent manner. We constructed a series of bph operon deletion mutants and tested for their biphenyl sensitivity. Growth inhibition by biphenyl was more prominent with the mutants defective in bphA1, bphB, bphC, and bphD, which were clustered in the bph operon and working in the early stage of the biphenyl degradation. The mutant defective in bphE, which was working at the late stage and forming a different cluster from the early stage genes, was not much inhibited by biphenyl. These indicate that biphenyl is detoxified by enzymes which function in the early stage of biphenyl assimilation and thus detoxification of substrates as well as energy acquisition could have played an important role in the evolution of the KKS102 bph operon.     

Polymorphism of dopamine receptor D4 exon I corresponding region in chicken

In stockbreeding, there are indications that behavioral traits of livestock have an effect on breeding and production. If the variation in individual behavior is related to that in neurotransmitter-related genes such as in humans, it would be possible to breed pedigrees composed of individuals having behavioral traits that are useful to production and breeding using selection based on genotypes. In this study, we investigated the exon I region of dopamine receptor D4 (DRD4), in which variation is related to psychiatric disorder in humans, in major poultry species namely Japanese quail (Coturnix japonica), chicken (Gallus gallus), ring-necked pheasant (Phasianus colchicus) and helmeted guinea fowl (Numida meleagris). Furthermore, we investigated Japanese cormorant (Phalacrocorax capillatus) and Japanese jungle crow (Corvus macrorhynchos) as an out-group. In these species of birds, the repeat of proline was identified in the region corresponding to the human polymorphic region. The repeat number was 9 in Japanese quail, ring-necked pheasant and Japanese cormorant; 12 in helmeted guinea fowl; and 3 in Japanese jungle crow. However, no polymorphism was found in these species. In contrast, polymorphism was observed in chicken and two alleles with 8 and 9 repeats were identified. Although 9 repeats (allele 9) were predominant in most chicken breeds, Black Minorca had only 8 repeats (allele 8). Intra-breed polymorphism was found in 6 out of 12 breeds, and two alleles (alleles 8 and 9) were detected in these breeds. This polymorphism, which is the first to be reported on a neurotransmitter-related gene in birds, would contribute significant information for elucidation of differences in behavioral traits in chicken breeds.     

Estrogen-Dependent Uterine Secretion of Osteopontin Activates Blastocyst Adhesion Competence

Embryo implantation is a highly orchestrated process that involves blastocyst-uterine interactions. This process is confined to a defined interval during gestation referred to as the “window of embryo implantation receptivity”. In mice this receptive period is controlled by ovarian estrogen and involves a coordination of blastocyst adhesion competence and uterine receptivity. Mechanisms coordinating the acquisition of blastocyst adhesion competence and uterine receptivity are largely unknown. Here, we show that ovarian estrogen indirectly regulates blastocyst adhesion competence. Acquisition of blastocyst adhesion competence was attributed to integrin activation (e.g. formation of adhesion complexes) rather than de novo integrin synthesis. Osteopontin (OPN) was identified as an estrogen-dependent uterine endometrial gland secretory factor responsible for activating blastocyst adhesion competence. Increased adhesion complex assembly in OPN-treated blastocysts was mediated through focal adhesion kinase (FAK)- and phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathways. These findings define for the first time specific regulatory components of an estrogen-dependent pathway coordinating blastocyst adhesion competence and uterine receptivity.     

Hydrogen Peroxide-dependent Synthesis of Flavonols in Mesophyll Cells of Vicia faba L.

Mesophyll cells of Vicia faba contain kaempferol and quercetinglycosides. When isolated mesophyll cells were treated with0.1 mM H₂O₂ for 2 h, the levels of these flavonols increasedby 10–70% of the control values (mean values, 19.6% and34.4% for kaempferol and quercetin glycosides, respectively).Such increases in levels of flavonols were also observed inisolated vacuoles of mesophyll cells. However, when mesophyllcells and vacuoles were treated with 10 mM H₂O₂₎degradationof flavonols was observed. These data suggest that H₂O₂ hastwo effects on the metabolism of flavonols: induction of theirsynthesis and stimulation of their oxidation. (Received March 6, 1989; Accepted July 10, 1989)