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71.
We previously reported that an acidomycin-resistant mutant of Serratia marcescens Sr41, SB304, and a mutant that was derived from SB304 and was resistant to a higher concentration of acidomycin, SB412, produced 5 and 20 mg of D-biotin, respectively, per liter of a medium containing sucrose and urea (N. Sakurai, Y. Imai, M. Masuda, S. Komatsubara, and T. Tosa, Appl. Environ. Microbiol. 59:2857-2863, 1993). In order to increase the productivity of D-biotin, the biotin (bio) operons were cloned from strains SB412, SB304, and 8000 (wild-type strain), and pLGM412, pLGM304, and pLGW101, respectively, were obtained through subcloning. These plasmids harbored 7.2-kb DNA fragments coding for the bioABFCD genes on a low-copy-number vector and were introduced into SB304, SB412, and 8000. Among the resulting recombinant strains, SB412(pLGM304) exhibited the highest D-biotin production (200 mg/liter) in the production medium. The plasmid was stably maintained in cells. Unexpectedly, SB412(pLGM412) grew very slowly, and the D-biotin productivity of this recombinant strain was not evaluated because pLGM412 was unstable. 相似文献
72.
Takaharu Ishibashi Mikio Nakazawa Shoichi Imai 《Molecular and cellular biochemistry》1993,119(1-2):109-120
Using31P-,23Na- and39K-NMR, we assessed ischemic changes in high energy phosphates and ion contents of isolated perfused rat hearts continuously and systematically. To discriminate intra- and extracellular Na+, a shift reagent (Dy(TTHA)3–) was used in23Na-NMR study. In39K-NMR study, the extracellular K+ signal was suppressed by inversion recovery pulse sequence in order to obtain intracellular K+ signal without using shift reagnets. During the early period of ischemia, increases in intracellular Na+ and inorganic phosphate (Pi) were observed in addition to the well-documented decreases in creatine phosphate and ATP and a fall of intracellular pH, suggesting an augmented operation of Na+–H+ exchange triggered by a fall of the intracellular pH resulted from breakdown of ATP. At around 15 min of ischemia, a second larger increase in intracellular Na+ and a decrease in intracellular K+ were observed in association with a second increase in Pi. This was accompnanied by an abrupt rise of the ventricular end-diastolic pressure. As there was a depletion of ATP at this time, the increase in intracellular Na+ and associated decrease in intracellular K+ may be explained by inhibition of the Na+–K+ ATPase due to the depletion of ATP. A longer observation with31P-NMR revealed a second phosphate peak (at lower magnetic field to ordinary Pi peak) which increased its intensity as ischemic time lengthened. The pH of this 2nd peak changed in parallel with the changes in pH of the bathing solution, indicating the appearance of a compartment whose hydrogen concentration is in equilibrium with that of the external compartment. Thus, the peak could be used as an index of irreversible membrane damage of the myocardium. 相似文献
73.
Tokuo Ogawa Junichi Sugenoya Norikazu Ohnishi Keiko Natsume Kazuno Imai Yoshikazu Kandori Akira Ishizuka Atsushi Osada 《European journal of applied physiology and occupational physiology》1993,67(4):354-359
We have examined the nonparallel changes in tampanic membrane temperatures (T
ty) from the two ears in response to various changes in body and head positions. Upon assuming a lateral recumbent position, the T
ty on the lower side increased while that on the upper side decreased. Pressure application over a wide area of the lateral chest only caused inconsistent and obscure asymmetric changes in T
ty. A lateral flexion of the head with the subject sitting upright and a rotation of the head to the side in a supine position induced an increase in the T
ty on the lower side compared to that on the upper side. The temperature and blood flow of the forehead often decreased on the lower side and increased on the upper side, although such responses were not always concomitant with the asymmetric changes in T
ty. A dorsal flexion of the head with the subject in a reclining position caused a slight increase in the T
ty, whereas raising the head upright induced a slight decrease in them. Two additional experiments were carried out with single photon emission computed tomography using 99mTc-hexamethylpropyleneamine oxime as tracer, and a slight, relative decrease in counts was noted in the right hemisphere during rotation of the head to the right. These results would strongly suggest that unilateral increases and decreases in T
ty could have been caused by one-sided decreases and increases, respectively, in blood flow to the brain and/or the tympanic membrane, induced by a vasomotor reflex involving vestibular stimulation. 相似文献
74.
Noriko Arase-Fukushi Hisashi Arase Bingyan Wang Mari Hirano Kazumasa Ogasawara Robert A. Good Kazunori Ono 《Microbiology and immunology》1993,37(11):883-894
Allo-chimerism and clonal elimination of self antigen (Ag) (Ia + Mls-1a) reactive Vβ6+ T cells were analyzed and compared between allogeneic bone marrow (BM) chimeras reconstituted with BM cells which had been treated with anti-Thy-1 monoclonal antibody (mAb) plus complement (C) (T– chimeras) and BM chimeras which had been reconstituted with BM cells pretreated with anti-Thy-1 mAb alone (T+ chimeras). When lethally irradiated AKR (Mls-1a) mice were reconstituted with BM cells from B10 or B10 H-2 congenic mice, both T+ and T– chimeras were entirely free of signs of graft-versus-host reaction (GVHR). However, complete replacement of the AKR lymphoid tissues by donor BM cells was accomplished at an early stage in T+ chimeras but not in T– chimeras. On the other hand, clonal elimination of Vβ6+ T cells reactive to the recipient Ag (Mls-1a) was abolished in T+ chimeras but successfully induced in T– chimeras. The Vβ6+ T cells not eliminated in T+ chimeras showed depressed responses against Mls-1a antigens. The findings herein demonstrate that T cells which contaminate a BM inoculum survive in recipient mice after treatment with anti-Thy-1 mAb without C in vitro followed by BMT. The surviving T cells have been estimated to represent fewer than 0.5% of the BM cells inoculated. These cells appear to accelerate the full replacement of recipient lymphoid tissues by donor cells. Furthermore, the T cells which survive in the marrow inoculum influence eventually the development of a tolerant state in the T cell repertoire of the donor. 相似文献
75.
Kazunori Yokoi Yoshiaki Yasumizu Naganari Ohkura Koei Shinzawa Daisuke Okuzaki Nene Shimoda Hideya Ando Nanako Yamada Manabu Fujimoto Atsushi Tanemura 《Pigment cell & melanoma research》2023,36(5):355-364
Vitiligo is a common depigmentation disorder characterized by the selective loss of melanocytes. In our daily clinic experience, we noticed that the skin tightness of hypopigmented lesions would be more evident in comparison to that of uninvolved perilesional skin in vitiligo patients. Therefore, we hypothesized that collagen homeostasis might be maintained in vitiligo lesions, irrespective of the substantial excessive oxidative stress that occurs in association with the disease. We found that the expression levels of collagen-related genes and anti-oxidative enzymes were upregulated in vitiligo-derived fibroblasts. Abundant collagenous fibers were observed in the papillary dermis of vitiligo lesions in comparison to uninvolved perilesional skin by electron microscopy. The production of matrix metalloproteinases that degraded collagen fibers was suppressed. The deposition of acrolein adduct protein, which is a product of oxidative stress, was significantly reduced in vitiligo dermis and fibroblasts. As part of the mechanism, we found upregulation of the NRF2 signaling pathway activity, which is an important defense system against oxidative stress. Taken together, we demonstrated that the anti-oxidative action and collagen production were upregulated and that the collagen degeneration was attenuated in vitiligo dermis. These new findings may provide important clues for the maintenance of antioxidant ability in vitiligo lesions. 相似文献
76.
77.
Reproductive behaviors related to habitat utilization were studied in males of the damsefly,Mnais nawai, which has two male forms, territorial orange-winged males (nawai) and non-territorial pale-orange-winged males (sahoi), at the upper part of a mountain stream where they partiallycoexist with a related species,Mnais pruinosa, which also has two male forms, territorial orange-winged males (esakii) and non-territorial hyaline-winged males (strigata). These two species showed parapatric distribution; the lower part of the stream was occupied byM. nawai, and the upper part byM. pruinosa. In the present study, cross-matings occurred between bothMnais species, although normal intraspecific matings occurred more frequently than cross-matings. Territorial males of both species copulated with conspecific females that entered their territory and guarded the ovipositing females, probably to avoid sperm displacement resulting from subsequent copulations. Severe competition for oviposition sites by territorial males even occurred between the two species. On the other hand, non-territorial males of both species have alternative mating strategies (including several tactics such as sneaking, takeover and interception). The possible benefits from conflict among territorial males of both species is discussed. 相似文献
78.
Tadayuki Miyamoto Susumu Kagawa Kouki Kitagawa Shiroh Futaki Hiromichi Yokoi Yoshihiro Tsuruo Kazunori Ishimura 《Histochemistry and cell biology》1996,105(2):101-109
We immunohistochemically studied the localization of 5-reductase type 1 in combination with androgen receptor (AR) expression in individual lobes of the prostates of intact and castrated rats. In the normal rat prostate, 5-reductase was localized in the cytoplasm of most epithelial cells in the ventral, dorsal, and lateral type 1 (L1) lobes. Epithelial cells of lateral type 2 (L2) lobes were negative for 5-reductase. AR was present in the nuclei of all epithelial and stromal cells throughout the prostate. The number of 5-reductase-immunoreactive cells rapidly decreased in the ventral and L1 lobes after castration, whereas many positive cells remained in the dorsal lobe even at 4 weeks after castration. AR immunostaining was lost in the ventral, dorsal, and L1 lobes at 1 week after castration, but remained in the L2 lobe of 4-week-castrated rats. Electron microscopic immunocytochemistry showed that 5-reductase was exclusively localized in the rough endoplasmic reticulum membranes and that there were no distinct structural differences between the positively and negatively stained epithelial cells. These findings suggested that the expression of 5-reductase type 1 in the epithelial cell is heterogeneous within and among the individual lobes of the rat prostate, and does not correspond to AR expression. 相似文献
79.
Photo-induced activation of cytochrome P450/reductase fusion enzyme coupled with spinach chloroplasts 总被引:1,自引:0,他引:1
Young-Sug Kim Masayuki Hara Kazunori Ikebukuro Jun Miyake Hideo Ohkawa Isao Karube 《Biotechnology Techniques》1996,10(10):717-720
Summary Photoactivation of cytochrome P450 monooxygenase was studied using a combination of spinach chloroplasts and yeast microsomes containing rat P4501A1/yeast reductase fusion enzyme. Under illumination, in the reaction mixture, NADP was reduced, transferring electrons to the P450/reductase fusion enzyme to convert 7-ethoxycoumarin to 7-hydroxycoumarin. 相似文献
80.
The red tide flagellate, Chattonella antiqua, was shown to beattracted to inorganic phosphate in both aged seawater and artificialseawater by well-test assays. 相似文献