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11.
H. Matsuoka H.-C. Yang T. Homma Y. Nemoto S. Yamada O. Sumita K. Takatori H. Kurata 《Applied microbiology and biotechnology》1995,43(1):102-108
Congo red was found to be feasible as a microscopic fluorescence indicator of hyphal growth at the single-hypha level. When 1 m Congo red was applied to mold of Aspergillus niger, the dye was found to a specific cell-wall component, chitin, without causing any inhibitory effect on hyphal growth. The bound Congo red emitted fluorescence at 614 nm. This binding reaction, however, proceeded more slowly than the growing speed of hypha. Consequently the fluorescence intensity was low at the apex where the surface area of the hypha was expanding rapidly. In contrast, as an apex where the growth was retarded, the fluorescence intensity became remarkably high. Therefore growing hyphae could be distinguished from non-growing hyphae by using Congo red. 相似文献
12.
Makoto Matsuoka Masanori Tamaoki Yuichi Tada Tatsuhito Fuyjimura Akemi Tagiri Naoki Yamamoto Yuriko Kano-Murakami 《Plant cell reports》1995,14(9):555-559
Transgenic rice plants (Oryza sativa cv. Nipponbare) carrying 1 or 2 copies of a rice homeobox gene, OSH1, under the control of the CaMV 35S promoter were generated. The transgene caused altered morphology of leaf, such as ligule-replacement and abnormal division of sclerenchyma cells. The phenotype of these leaves resembles that of maize leaf morphological mutant, Knotted 1, which is caused by duplication of the KN1 gene (Veit et al., 1990). The in situ hybridization analysis has revealed that the expression of endogenous OSH1 is mainly localized in developing vascular strands of stem. We have discussed the biological roles of OSH1 in rice based on these results. 相似文献
13.
A specific heterotypic cell adhesion activity between members of carcinoembryonic antigen family, W272 and NCA, is mediated by N-domains 总被引:11,自引:0,他引:11
S Oikawa C Inuzuka M Kuroki F Arakawa Y Matsuoka G Kosaki H Nakazato 《The Journal of biological chemistry》1991,266(13):7995-8001
The Ca(2+)-independent homotypic and heterotypic cell adhesion activities of a carcinoembryonic antigen (CEA) family member, W272 (CGM6), whose cDNA has recently been isolated from libraries of human peripheral leukocytes of apparently normal subjects (Arakawa, F., Kuroki, Mo., Misumi, Y., Oikawa, S., Nakazato, H., and Matsuoka, Y. (1990) Biochem. Biophys. Res. Commun. 166, 1063-1071) and spleen of chronic myelogenous leukemia patients (Berling, B., Kolbinger, F., Grunert, F., Thompson, J. A., Brombacher, F., Buchegger, F., von Kleist, S., and Zimmermann, W. (1990) Cancer Res. 50, 6534-6539) has been examined. Chinese hamster ovary cells transfected with the cDNA for W272, CEA, nonspecific cross-reacting antigen (NCA), and various antigens containing chimeric N-domain have been used. The W272 producers did not show homotypic binding at all but bound only to the cells expressing NCA and a chimeric CEA whose N-domain is substituted by that of NCA, indicating the major contribution of N-domain of NCA in the specific binding. The importance of the N-terminal region of NCA N-domain for the W272-NCA binding has been shown by detailed analysis using COS-1 cells producing various NCA whose N-domain are chimera of that of NCA and CEA. The strict heterotypic nature of the W272-NCA adhesion strongly suggests that the cell adhesion activities exhibited by CEA family members are not the fortuitous activity but the specific one which have some important physiological roles. 相似文献
14.
Sodium-calcium exchange current was isolated in inside-out patches excised from guinea pig ventricular cells using the giant patch method. The outward exchange current decayed exponentially upon activation by cytoplasmic sodium (sodium-dependent inactivation). The kinetics and mechanism of the inactivation were studied. (a) The rate of inactivation and the peak current amplitude were both strongly temperature dependent (Q10 = 2.2). (b) An increase in cytoplasmic pH from 6.8 to 7.8 attenuated the current decay and shifted the apparent dissociation constant (Kd) of cytoplasmic calcium for secondary activation of the exchange current from 9.6 microM to < 0.3 microM. (c) The amplitude of exchange current decreased synchronously over the membrane potential range from -120 to 60 mV during the inactivation, indicating that voltage dependence of the exchanger did not change during the inactivation process. The voltage dependence of exchange current also did not change during secondary modulation by cytoplasmic calcium and activation by chymotrypsin. (d) In the presence of 150 mM extracellular sodium and 2 mM extracellular calcium, outward exchange current decayed similarly upon application of cytoplasmic sodium. Upon removal of cytoplasmic sodium in the presence of 2-5 microM cytoplasmic free calcium, the inward exchange current developed in two phases, a fast phase within the time course of solution changes, and a slow phase (tau approximately 4 s) indicative of recovery from sodium-dependent inactivation. (e) Under zero-trans conditions, the inward current was fully activated within solution switch times upon application of cytoplasmic calcium and did not decay. (f) The slow recovery phase of inward current upon removal of cytoplasmic sodium was also present under the zero-trans condition. (g) Sodium-dependent inactivation shows little or no dependence on membrane potential in guinea pig myocyte sarcolemma. (h) Sodium-dependent inactivation of outward current is attenuated in rate and extent as extracellular calcium is decreased. (i) Kinetics of the sodium-dependent inactivation and its dependence on major experimental variables are well described by a simple two-state inactivation model assuming one fully active and one fully inactive exchanger state, whereby the transition to the inactive state takes place from a fully sodium-loaded exchanger conformation with cytoplasmic orientation of binding sites (E1.3Ni). 相似文献
15.
The in vitro micronucleus (MN) test was carried out simultaneously with the conventional chromosomal aberration (CA) test on 11 clastogenic chemicals or spindle poisons with different modes of action using a Chinese hamster cell line (CHL). The method of slide preparation for the MN test was the same as that for the conventional metaphase analysis, except that 1% acetic acid in methanol was used as the cell suspension medium for air-drying (to preserve the cytoplasm around the nucleus). All chemicals tested induced micronuclei reproducibly and dose-dependently in good agreement with the results of metaphase analysis (r = 0.99). Since the MN test methodology is simple and the observation of MN is less subjective than that of CA, we conclude that the in vitro MN test would be a good alternative to the conventional CA test for screening the genotoxicity of chemicals. 相似文献
16.
Six model ethylating agents were tested for clastogenic potency by means of a new technique of the micronucleus assay with mouse peripheral blood cells using acridine orange (AO)-coated slides, to evaluate the test. The alkylating agents were: N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG), N-ethyl-N-nitrosourea (ENU), diethylsulfate (DES), ethyl methanesulfonate (EMS), epichlorohydrin (ECH) and ethylene dibromide (EDB). The animals were given a single intraperitoneal injection of the following doses of the chemicals: ENNG and ENU, 25, 50 and 100 mg/kg; EMS and DES, 100, 200 and 400 mg/kg body weight. For EDB and ECH, the doses were 50, 100 and 200 mg/kg, given twice, 24 h apart. Before and after the injection, blood samples were taken from the tails at 24-h intervals up to 72 h and preparations were made on AO-coated slides. For each dose group, 4 animals were used and 1000 reticulocytes were examined per slide for the presence of micronuclei. At the optimum induction time of 48 h, ENU induced micronucleated reticulocytes (MNRETs) at all 3 doses. ENNG and EMS induced MNRETs significantly at 2 dose levels each and DES only at the highest dose. ECH and EDB failed to induce MNRETs. On the basis of the dose of chemical needed to double the spontaneous frequency, the order of clastogenic potency was ENU greater than ENNG greater than EMS greater than DES. The results obtained compared favorably with those from other in vivo methods. The present technique proves to be simple, flexible and relatively sensitive. Shifts in the optimum induction peak in individual animals and by some chemicals can be picked up easily which is important when testing weak mutagens and chemicals with an unknown mechanism of action. 相似文献
17.
T Suzuki K Tamai Y Kodama A O Asita A Matsuoka T Sofuni M Kurita H Ohtsuki T Hiwatashi M Hayashi 《Mutation research》1992,278(2-3):169-173
Micronucleus assays using mouse peripheral blood stained vitally on acridine orange (AO)-coated slides were evaluated at two laboratories with 7,12-dimethylbenz[a]anthracene (DMBA) and compared with the standard bone marrow assay. DMBA was administered by single intraperitoneal injection to CD-1 mice at doses ranging from 5 to 80 mg/kg, then 5 microliters of peripheral blood was sampled from a tail vein at 24, 48, 72, 96, and 120 h after treatment. Similar incidences of micronucleated young erythrocytes were observed in peripheral blood reticulocytes and bone marrow polychromatic erythrocytes. The dose response of micronucleated reticulocytes was delayed compared to that of micronucleated polychromatic erythrocytes. The dose-response curves after treatment with DMBA differed depending on the sampling times, which revealed the difficulty of obtaining accurate dose-response relations in the micronucleus assay. The present result demonstrated that the simple and rapid AO supravital staining method is a valuable and easier method for obtaining dose- and time-response data for quantification of micronucleus induction by chemicals. 相似文献
18.
The effect of thrombospondin, a major glycoprotein in the platelet alpha-granule, on the erythrocyte aggregation rate was investigated. Venous blood was sampled from 8 healthy male volunteers and anticogulated with 1.1 mg/ml EDTA(K2). The erythrocyte aggregation rate of each blood sample was measured with a whole-blood erythrocyte aggregometer before and after incubation with murine monoclonal antibody against human platelet thrombospondin. After 15 min incubation, the erythrocyte aggregation rate exhibited a significant decrease to 0.055 +/- 0.022/s, representing 71.9 +/- 8.7% of the control value (0.075 +/- 0.028/s) (p less than 0.0005). The results obtained suggest that thrombospondin may participate in the control of erythrocyte aggregability in the circulating blood. 相似文献
19.
Structure, genetic mapping, and expression of the gene for pyruvate, orthophosphate dikinase from maize 总被引:13,自引:0,他引:13
M Matsuoka 《The Journal of biological chemistry》1990,265(28):16772-16777
20.
Native oxymyoglobin (MbO2) was isolated directly from the skeletal muscle of bigeye tuna (Thunnus obesus) with complete separation from metmyoglobin (metMb) on a CM-cellulose column. It was examined for its stability properties over a wide range of pH values (pH 5-12) in 0.1 M buffer at 25 degrees C. When compared with sperm whale MbO2 as a reference, the tuna MbO2 was found to be much more susceptible to autoxidation. Kinetic analysis has revealed that the rate constant for a nucleophilic displacement of O2- from MbO2 by an entering water molecule is 10-times higher than the corresponding value for sperm whale MbO2. The magnitude of the circular dichroism of bigeye tuna myoglobin at 222 nm was comparable to that of sperm whale myoglobin, but its hydropathy profile revealed the region corresponding to the distal side of the heme iron to be apparently less hydrophobic. The kinetic simulation also demonstrated that accessibility of the solvent water molecule to the heme pocket is clearly a key factor in the stability properties of the bound dioxygen. 相似文献