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991.
Koji Asami Akihiko Irimajiri Tetsuya Hanai Noriyuki Shiraishi Kozo Utsumi 《生物化学与生物物理学报:生物膜》1984,778(3):559-569
A re-evaluation of the dielectric studies on isolated mitochondria (Pauly, H., Packer L., and Schwan, H.P. (1960) J. Biophys. Biochem. Cytol. 7, 589–601, and ibid. 7, 603–612) is presented. The suspensions of ‘mitoplasts’ prepared from rat liver mitochondria by a hyposmotic (10 mM KCI) treatment showed a dielectric dispersion with its characteristic frequency lying in the 1–100 MHz range. In the analysis of data special emphasis was put on the choice of the theoretical models to employ after serutiny of their applicability to the suspensions tested. As such we adopted the theory of Hanai et al. (Hanai, T., Asami, K., and Koizumi, N. (1979) Bull. Inst. Chem. Res., Kyoto Univ. 57, 297–305) that was advanced to include concentrated suspensions of shelled spheres. Curve fittings based on that theory resulted in a better agreement with experiment than the fittings based on a conventional theory for dilute suspensions. Major findings from our analyses on the swollen mitoplasts are that: (i) the limiting membrane of the mitoplasts has a specific electrical capacity of 1 μF/cm2, (ii) the ratio of permittivity (or dielectric constant) for the mitoplast interior and permittivity for the external medium is 0.6–0.7, and (iii) the conductivity ratio between the interior phase and the medium is approx. 0.6. Reasons for discrepancy between the results of Pauly et al. and ours are discussed. 相似文献
992.
Itsuki Oshima Hideki Yamada Maki Goto Koji Sato Shizufumi Ebihara 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1989,166(2):217-226
Summary Although pinealectomy or blinding resulted in loss of the clarity of the free-running rhythm of locomotor activity and body temperature and reduced the peak level of circulating melatonin rhythms to approximately a half in intact pigeons, neither pinealectomy nor blinding abolished any of these rhythms. However, when pinealectomy and blinding were combined, the rhythms of locomotor activity and body temperature disappeared in prolonged constant dim light, and melatonin concentration was reduced to the minimum level of detection. In order to examine the role of melatonin in the pigeon's circadian system, it was administered either daily or continuously to PX + EX-pigeons in LLdim. Daily administration of melatonin restored circadian rhythms of locomotor activity which entrained to melatonin injections, but continuous administration did not induce any remarkable change of locomotor activity. These results suggest that melatonin synthesized in the pineal body and the eye contributes to circulating melatonin and its rhythmicity is important for the control of circadian rhythms of locomotor activity and body temperature in the pigeon.Abbreviations
LD
Light-dark
-
LLdim
constant dim light
-
LLbright
constant bright light
-
PX
pinealectomy
-
EX
blinding
-
SCN
suprachiasmatic nucleus 相似文献
993.
Koji Ohnishi 《Origins of life and evolution of the biosphere》1984,14(1-4):717-724
Homologies were searched among the published primary sequences of 51E.
coli ribosomal proteins, partly by eye and partly by computer-assisted methods. By employing Moore and Goodman's alignment statistics for evaluating homology levels, 33 out of these 51 ribosomal proteins has been classified into 9 homology groups, some of which being yet tentative and remaining to be further analyzed. Taking it into consideration that most ribosomal protein genes are clustered atstr-stc region,rif region and several other regions, these results strongly suggest that most or all of the contemporary ribosomal proteins must have evolved by repeated gene duplications ofvery
few (oronly
one) primitive ancestral ribosomal protein gene(s). Thus it is most reasonable to propose that a small
ribosome consisting of very few (or only one) ribosomal protein(s) must have existed as a primitive protein-synthesizing apparatus. 相似文献
994.
One physiological characteristic of an Al-tolerant cell line(TA-1) selected from a cultured carrot cell line (SO-1) wasthe release of more citric acid into the medium than the parentalSO-1 line. Aluminum chloride was added to the media at a concentration,at which SO-1 as well as TA-1 could grow normally without inhibition.The amounts of citric acid and the soluble Al present in themedium were determined during the growth period. Much citricacid was released from TA-1 cells into the medium in the firsthalf of the culture period. At the time of maximum growth, theamount of citric acid in the medium of TA-1 cells was twiceas much as in the medium of SO-1 cells. The precipitates ofAl compound(s), which were formed in the medium by the additionof AlCl3 as the Al source, became soluble as culture proceeded,depending on the amount of citric acid present in the medium. (Received September 3, 1983; Accepted May 9, 1984) 相似文献
995.
Tsuyoshi Muramatsu Kenji Komori Narumi Sakurai Koji Yamada Yasuyuki Awasaki Kazumasa Fukuda Tatsuya Oda 《Journal of Protein Chemistry》1996,15(8):709-719
The complete amino acid sequences of two isoforms, SP1 and SP2, of mannuronate lyase from a wreath shell,Turbo cornutus, were determined to elucidate amino acid residues responsible for causing the more stable protein conformation of SP2. The sequences of the two isoforms were identical except for two hydrophobic C-terminal amino acid residues of SP2, Ile and Leu, which were additionally attached to Thr of the C-terminal residue of SP1 (253 residues in total). The molecular weight of SP2 was calculated to be 28,912 from the amino acid sequence data. Two disulfide bond cross-linkages were found to be between 106 and 115 and between 145 and 150, and a partially buried single SH group was located at 236. A carbohydrate chain that consisted of 3 GlcNAc, 3 Fuc, and 1 Man was anchored on Asn-105 in a typical carbohydrate-binding motif of Asn-X-Ser. This is the first evidence of the primary structure of mannuronate lyase, and no significant homology of the amino acid sequence among other proteins was found. The C-terminal truncated SP2, which was produced by digestion with carboxypeptidase Y and corresponded structurally to SP1, showed a thermal stability identical to that of SP1. These results indicate that the higher stability of SP2 than SP1 arises from the presence of the C-terminal two hydrophobic amino acid residues. 相似文献
996.
The main component of the mucilage in the bulbs of Suisen (Narcissus tazetta L., var. chinensis Roem) has been shown to be a glucomannan composed of D-glucose and D-mannose in the ratio of 2:3 and having a relatively low degree of branching. Acetolysis of the polysaccharide led to the isolation of β-(1→4)-β-(1→3)-linked oligosaccharides composed of D-mannose and/or D-glucose residues. The average chain length (c.1.) of the polysaccharide was determined by methylation analysis to be about 22. 相似文献
997.
In an attempt to clarify the comparative values of serological and microbiological examinations for the early diagnosis of systemic candidiasis, antibodies against Candida albicans, serum mannan, and the D-arabinitol creatinine ratio were investigated in a patient with aortic valve endocarditis associated with carcinoma of the bile duct. Candida precipitins and the antibody titer against Candida cell wall mannan were examined by an immunodiffusion technique and hemagglutination test, respectively. Serum mannan was tested by enzyme-linked immunosorbent assay (ELISA) using the biotin-streptavidin procedure. The upper limit of negativity of the assay was determined by adding 0.06 to the absorbance of pooled serum from healthy laboratory workers. This value ws about 0.8 ng/ml with ELISA. The D-arabinitol concentration in serum was examined by an enzymatic fluorometric method. Rising antibody titers against C. albicans, mannan antigenemia, and an elevated D-arabinitol creatinine ratio were first observed between the 11th and 12th hospital days. Blood cultures obtained on 8th, 9th, and 11th hospital days grew C. albicans after 3 to 4 days of incubation. Of 11 serum samples, 5 were positive for mannan, whereas D-arabinitol creatinine ratio was positive in 7 of 9 samples. Blood cultures was the earliest evidence of Candida infections in our cases. However, because of saprophytic nature of Candida species, tests for antibodies, antigenemia, and the D-arabinitol creatinine ratio in combination with blood cultures are necessary to confirm systemic candidiasis at an early stage of infection.Abbreviations ELISA
enzyme-linked immunosorbent assay 相似文献
998.
Habenaria is one of the largest orchid genera, with its main centers of diversity in Brazil, eastern Asia and central and southern Africa. In spite of its diversity, the pollinators of few Habenaria spp. have been studied, while most published reports indicate that Habenaria spp. are mainly pollinated by moths. Here we report that the diurnal skipper Parnara guttata can be at least one of the pollinators of Habenaria radiata. Skippers have generally been thought of as nectar thieves, transferring few pollen grains. However, orchids transmit their pollen grains in large groups within pollinia. Such innovation can probably render the skipper a pollinator of H. radiata. 相似文献
999.
Motif analysis of PGa4 indicated that eight consecutive guanine residues were most important for pyrroloquinoline quinine
glucose dehydrogenase (PQQGDH) recognition. Because the truncated mutants minimized unexpected interactions between PGa4 and
the target-binding aptamer, they will now facilitate the construction of a highly sensitive detection system using a PQQGDH-labeled
diagnostic marker-binding aptamer. 相似文献
1000.
Koji Tsuchida 《Population Ecology》1991,33(2):361-366
Females in hibernation site (FH) were significantly larger than foundresses (FO), suggesting that larger FH were less successful in founding their nest. Body size of FO did not correlate with two nest characters, i.e., the number of cells at pupal stage (CP) and the timing of nest foundation (DP). However, CP negatively correlated with DP in 2 of 3 studied years, suggesting that foundress who founded her nest earlier than others tended to construct larger number of cells irrespective of her body size. 相似文献