Purified tyrosine kinases, the EGF receptor kinase and the src kinase, can catalyze the phosphorylation of the band 3 protein from human erythrocytes

The band 3 glycoprotein from human erythrocytes was found to be phosphorylated on tyrosine residues by the purified EGF receptor kinase and the purified src kinase in vitro. Kinetic analysis revealed that Km of the band 3 protein phosphorylation by the EGF receptor kinase was 0.17 microM and 0.65 microM in the absence and presence of EGF (3 X 10(-7)M), respectively, and that in the case of the src kinase it was 0.4 microM. From these data the band 3 protein can be regarded as one of the best substrates common for the EGF receptor kinase and the src kinase in vitro.     

Habitat generalization of a predatory ladybird,Harmonia yedoensis (Coleoptera: Coccinellidae), in an allopatric area with respect to its sibling species Harmonia axyridis

In central Japan, Harmonia yedoensis is a specialist ladybird that is confined to pine tree habitats, whereas its sibling species Harmonia axyridis is a generalist that feeds on a wide range of aphid species in nature. Interestingly, H. axyridis is not distributed in the Ryukyu Archipelago, southern Japan. We hypothesized that the ecological niche of H. yedoensis should be wider in the Ryukyu Archipelago, where its competitor species in central Japan, H. axyridis, is absent. We undertook fieldwork and a survey of published works to examine habitat utilization by H. yedoensis in the Ryukyu Archipelago. We found that H. yedoensis adults in the Ryukyu Archipelago visited several kinds of deciduous trees, including wild tamarind, Chinese hibiscus, Taiwan cherry and Malayan banyan, as well as pine trees. These observations suggest that habitat generalization has occurred in H. yedoensis in the Ryukyu Archipelago, where it does not compete with H. axyridis.     

Effects of acorn masting on population dynamics of three forest-dwelling rodent species in Hokkaido,Japan

The effects of the abundance of acorns of the oak, Quercus crispula, on the population dynamics of three rodent species (Apodemus speciosus, A. argenteus, and Clethrionomys rufocanus) were analyzed using time series data (1992–2006). The data were obtained in a forest in northern Hokkaido, Japan, by live trapping rodents and directly counting acorns on the ground. Apodemus speciosus generally increased in abundance following acorn masting. However, the clear effect of acorn abundance was not detected for the other two rodent species. Acorns of Q. crispula contain tannins, which potentially have detrimental effects on herbivores. Apodemus speciosus may reduce the damage caused by acorn tannins with tannin-binding salivary proteins and tannase-producing bacteria, whereas such physiological tolerance to tannins is not known in the other two rodent species. The differences in the effects of acorns between the three species may be due to differences in their physiological tolerance to tannins.     

Efficacy of a hybrid assistive limb in post-stroke hemiplegic patients: a preliminary report

Background  

Robotic devices are expected to be widely used in various applications including support for the independent mobility of the elderly with muscle weakness and people with impaired motor function as well as support for nursing care that involves heavy laborious work. We evaluated the effects of a hybrid assistive limb robot suit on the gait of stroke patients undergoing rehabilitation.     

Structure-function studies of human aromatase

Site-directed mutagenesis experiments have been carried out to determine the structure-function relationship of human aromatase. By sequence comparison, the region in aromatase that corresponds to the distal helix of cytochrome P-450cam has been identified to be Gln-298 to Val-313. Eight aromatase mutants with changes in this region, i.e. C299A, E302L, P308F, D309N, D309A, T310S, T310C, and S312C, have been generated using a mammalian cell stable-expression system. The results from site-directed mutagenesis studies indicate that the region containing Gln-298 to Val-313 is indeed a very important part of the active site of aromatase. The catalytic properties of P308F, D309N, and D309A have been examined in detail and are discussed. Active site-directed labeling is also an important approach to investigate the structure-function relationship of aromatase. HPLC-linked electrospray mass spectrometry is indicated as a useful technique for the characterization of active site-directed probe-modified enzyme. The mass spectral analysis of aromatase suggests that aromatase is glycosylated.     

A 1H-NMR study of electronic structure of the active site of Galeorhinus japonicus metmyoglobin

The ferric high-spin form of the myoglobin from the shark Galeorhinus japonicus, which possesses a Gln residue at the distal site instead of the usual His residue, has been studied by 1H-NMR spectroscopy. Using the heme meso-proton (C5H, C10H, C15H and C20H) resonance shift as a diagnostic probe for identifying the coordination system of the iron center in ferric high-spin form of hemoprotein, it has been shown that G. japonicus metmyoglobin (metMb) possesses the pentacoordinated active site. The pH-dependence study of NMR spectra of G. japonicus metMb revealed the appearance of the hydroxyl form of metMb at high pH, indicating that the protein undergoes the transition between the acidic and alkaline forms. The pK value and the rate for this acid-alkaline transition in G. japonicus metMb were found to be approximately 10 and much less than 4 x 10(2) s-1, respectively. Since the pK value of the acid-alkaline transition for the pentacoordinated heme in Aplysia limacina metMb is 7.8 [Giacometti, G.M., Das Ros, A., Antonini, E. & Brunori, M. (1975) Biochemistry 14, 1584-1588] and that of the hexacoordinated heme in sperm whale metMb is 9.1 [Brunori, M., Antonini, E., Fasella, P., Wyman, J. & Rossi-Fanelli, A. (1968) J. Mol. Biol. 34, 497-504], the OH- affinity of the ferric heme iron does not appear to depend on its coordination system. The acid-alkaline transition rate in A. limacina metMb was reported to be much less than 1.5 x 10(2) s-1 [Pande, U., La Mar, G.N., Lecomte, J.T.J., Ascoli, F., Brunori, M., Smith, K.M., Pandey, R.K., Parish, D.W. & Thanabal, V. (1986) Biochemistry 25, 5638-5646] and therefore a slow transition rate may be unique to the pentacoordinated active site of Mb.     

Synthesis of 19-hydroxy-[7-2H2]androstenedione for human metabolism studies

19-Hydroxyandrostenedione (19-OHA), highly labeled with deuterium at position 7, was synthesized from unlabeled androstenediol diacetate. The deuterium labels were introduced into the 7-keto compound with dichloroaluminum deuteride to obtain [7-2H2]androstenediol. The labeled androstenediol diacetate was converted to the labeled 19-OHA by a five-step sequence without appreciable loss of deuterium. The labeled 19-OHA is useful as an internal standard for gas chromatography-mass spectroscopy analysis of the endogenous levels and as a tracer for in vivo metabolic studies.     

Functional analysis of mononuclear cells infiltrating into tumors. II. Differential ability of mononuclear cells obtained from various tissues to produce helper factors that are involved in the generation of cytotoxic cells

The requirement of CGF in the generation of cytotoxic cells against syngeneic tumor cells (T-9) and in the rejection of transplanted T-9 cells has been investigated. Spleen cells obtained from sensitized rats showed strong cytotoxicity against 51Cr-labeled T-9 cells upon incubation with CGF for 48 hr. Human recombinant IL 2 and rat IFN failed to generate cytotoxic cells from spleen cells of sensitized rats. CGF are produced by spleen cells upon inoculation of T-9 cells into sensitized rats as a host in vivo immune response. Production of CGF preceded the appearance of cytotoxic cells in regional lymph node and tumor tissues. In those rats, inoculated tumor cells were eventually rejected. In contrast, spleen cells failed to produce CGF upon inoculation of T-9 cells in unsensitized rats. Cytotoxic cells were not detected in unsensitized rats, and inoculated tumor grew in those rats. Thus, CGF is likely to be involved in the generation of cytotoxic cells and in the rejection of inoculated syngeneic tumor cells. A Mono Q anion-exchange column with an FPLC system allowed the chromatographic separation of CGF from IL 1, IL 2, IL 3, and CSF.