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81.
Chlorella vulgaris 11h cells grown in air enriched with 4% CO2(high-CO2 cells) had carbonic anhydrase (CA) activity whichwas 20 to 90 times lower than that of algal cells grown in ordinaryair (containing 0.04% CO2, low-CO2 cells). The CO2 concentrationduring growth did not affect either ribulose 1,5-bisphosphate(RuBP) carboxylase activity or its Km for CO2. When high-CO2 cells were transferred to low CO2 conditions,CA activity increased without a lag period, and this increasewas accompanied by an increase in the rate of photosynthetic14CO2 fixation under 14CO2-limiting conditions. On the otherhand, CA activity as well as the rate of photosynthetic 14CO2fixation at low 14CO2 concentrations decreased when low-CO2cells were transferred to high CO2 conditions. Diamox, an inhibitor of CA, at 0.1 mM did not affect photosynthesisof low-CO2 cells at high CO2 concentration (0.5%). Diamox inhibitedphotosynthesis only under low CO2 concentrations, and the lowerthe CO2 concentration, the greater was the inhibition. Consequently,the CO2 concentration at which the rate of photosynthesis attainedone-half its maximum rate (Km) greatly increased in the presenceof this inhibitor. When CO2 concentration was higher than 1%, the photosyntheticrate in low-CO2 cells decreased, while that in high-CO2 cellsincreased. Fractionation of the low-CO2 cells in non-aqueous medium bydensity showed that CA was fractionated in a manner similarto the distribution of chlorophyll and RuBP carboxylase. These observations indicate that CA enhances photosynthesisunder CO2-limiting conditions, but inhibits it at CO2 concentrationshigher than a certain level. The mechanism underlying the aboveregulatory functions of CA is discussed.
1This work was reported at the International Symposium on PhotosyntheticCO2-Assimilation and Photorespiration, Sofia, August, 1977 (18).Requests for reprints should be addressed to S. Miyachi, RadioisotopeCentre, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan. (Received December 11, 1978; ) 相似文献
82.
83.
Nobuhiro Akuzawa Makoto Kurabayashi Tsukasa Suzuki Daisuke Yoshinari Mitsunobu Kobayashi Yoshifumi Tanahashi Fujio Makita Ryusei Saito 《Diagnostic pathology》2017,12(1):74
Background
Spontaneous isolated dissection of the superior mesenteric artery (SMA) can lead to bowel ischemia, aneurysm rupture, or even death. Studies have suggested that mechanical or hemodynamic stress on the vascular wall of the SMA may be a contributor, but its pathogenesis is unclear.Case presentation
A 57-year-old Japanese man with a history of untreated hypertension and hyperuricemia was admitted to our hospital with the sudden onset of severe epigastric pain. Laboratory findings showed elevated white blood cell count and C-reactive protein, and contrast-enhanced computed tomography (CT) of the abdomen demonstrated arterial dissection with luminal stenosis and aneurysm formation at the distal portion of the SMA after the branching of the jejunal artery, and intravenous nicardipine was administered. The patient’s epigastric pain resolved spontaneously but recurred on day 6 of his hospital stay. Contrast-enhanced abdominal CT revealed an enlarged aneurysm with wall thinning. Because of the risk of aneurysm rupture, the decision was made to perform aneurysmectomy and bowel resection on day 6. Histologic examinations revealed two separate dissecting lesions: one latent and the other resulting in aneurysm formation. Both lesions showed characteristics of segmental arterial mediolysis (SAM) with lack of arterial media, absence of internal and external elastic laminae and intimal proliferation.Conclusions
Histologic findings in the present case suggest that mechanical or hemodynamic stress on the vascular wall and SAM-related vascular vulnerability may concomitantly contribute to the onset of isolated SMA dissection.84.
Kiyotaka Chinzei Kantaro Fujioka Hiroshi Kitazato Itaru Koizumi Tadamichi Oba Motoyoshi Oda Hisatake Okada Toyosaburo Sakai Yoshihiro Tanimura 《Marine Micropaleontology》1987,11(4)
Downcore changes in microfossil assemblages and oxygen isotope ratios in three piston cores recovered from the Northwestern Pacific, off central Japan, show that the subtropical Kuroshio front was located to the south of C-4 core site (Lat. 33° N) during the last glacial. The front then advanced northward, passing over the C-4 site and the C-6 site (34.6° N) at about 13 ka and 10 ka, respectively, and reached the C-1 core site (36° N) at about 7 ka. After 5.5 ka it retreated to the area between the C-1 and C-6 sites. A brief but significant cold event, the readvance of the cold Oyashio Current, is recognized between 11 and 10 ka in the two northern cores, but the current did not reach the southern C-4 site. A contemporaneous cold event is known in the North Atlantic, and the cooling was probably a global phenomenon likely to be associated with lowering of sea level. Contamination of isotopically light water is apparent between 14 and 11 ka in the marked change in isotopic composition of benthic foraminifers. Oxygen isotope ratios of planktonic foraminifers show that prior to the advance of the Kuroshio front, the surface water at these core sites was isotopically lighter than the Kuroshio water at that time. 相似文献
85.
Go Suzuki Wataru Okada Yoko Yasutake Hidekazu Yamamoto Iwao Tanita Hiroshi Yamashita Takeshi Hayashibara Toshiaki Komatsu Toru Kanyama Masahito Inoue Masashi Yamazaki 《Restoration Ecology》2020,28(5):1172-1182
Larval recruitment is essential for sustaining coral communities and a fundamental tool in some interventions for reef restoration. To improve larval supply and post‐settlement survival in sexually assisted coral restoration efforts, an integrated in situ collector system, the larval cradle, was designed to collect spawned gametes then culture the resulting larvae until settled on artificial substrates. The final design of the larval cradle was cylindrical, a nylon mesh structure with a volume of 9 m3, suspended in the sea and extending vertically toward the seabed. We found three key design features that improved the efficiency of the apparatus: (1) an open area of sea surface and mesh size of less than 100 μm produced high fertilization and optimal survival (>90%), (2) a special skirt‐shaped net (3 m in diameter) with a connection hose for attaching the cradle to collect bundles from many adult colonies over a wide area and at various depths, and (3) adding short square tube pieces, called square hollow sections, as a substrate for enhancing larval settlement and survival, to a larval cradle at 4 days after spawning was optimal for uniform settlement. This system allowed not only the collection of several million eggs, but also subsequent production of several thousand settled juvenile corals, without land facilities. Our design achieved several hundred times higher survival for early life stages of Acropora tenuis compared to nature. 相似文献
86.
Tagaya Y Osaki A Miura A Okada S Ohshima K Hashimoto K Yamada M Satoh T Shimizu H Mori M 《Protein and peptide letters》2012,19(9):997-1004
Nucleobindin-2 is a 420 amino acid EF-hand Ca2+ binding protein that can be further processed to generate an 82 amino terminal peptide termed Nesfatin-1. To examine the function of secreted Nucleobindin-2 in adipocyte differentiation, cultured 3T3-L1 cells were incubated with either 0 or 100 nM of GST, GST-Nucleobindin-2, prior to and during the initiation of adipocyte differentiation. Nucleobindin-2 treatment decreased neutral lipid accumulation (Oil-Red O staining) and expression of several marker genes for adipocyte differentiation (PPARγ, aP2, and adipsin). When Nucleobindin- 2 was constitutively secreted into cultured medium, cAMP content and insulin stimulated CREB phosphorylation were significantly reduced. On the other hand, intracellularly overexpressed Nucleobindin-2 failed to affect cAMP content and CREB phosphorylation. Taken together, these data indicate that secreted Nucleobindin-2 is a suppressor of adipocyte differentiation through inhibition of cAMP production and insulin signal. 相似文献
87.
Sazaki G Van Driessche AE Dai G Okada M Matsui T Otálora F Tsukamoto K Nakajima K 《Protein and peptide letters》2012,19(7):743-760
To start systematically investigating the quality improvement of protein crystals, the elementary growth processes of protein crystals must be first clarified comprehensively. Atomic force microscopy (AFM) has made a tremendous contribution toward elucidating the elementary growth processes of protein crystals and has confirmed that protein crystals grow layer by layer utilizing kinks on steps, as in the case of inorganic and low-molecular-weight compound crystals. However, the scanning of the AFM cantilever greatly disturbs the concentration distribution and solution flow in the vicinity of growing protein crystals. AFM also cannot visualize the dynamic behavior of mobile solute and impurity molecules on protein crystal surfaces. To compensate for these disadvantages of AFM, in situ observation by two types of advanced optical microscopy has been recently performed. To observe the elementary steps of protein crystals noninvasively, laser confocal microscopy combined with differential interference contrast microscopy (LCM-DIM) was developed. To visualize individual mobile protein molecules, total internal reflection fluorescent (TIRF) microscopy, which is widely used in the field of biological physics, was applied to the visualization of protein crystal surfaces. In this review, recent progress in the noninvasive in situ observation of elementary steps and individual mobile protein molecules on protein crystal surfaces is outlined. 相似文献
88.
Daisuke Tsuru Heizo Kira Takehiko Yamamoto Juichiro Fukumoto 《Bioscience, biotechnology, and biochemistry》2013,77(3):330-335
Some physicochemical properties and amino acid composition of the alkaline protease of B. amylosacchariticus were determined. The molecular weight and sedimentation coefficient were estimated to be 22,700 and 2.89 s, respectively, and the amino terminal amino acid was identified to be alanine. The enzyme contained 15.9% of nitrogen and was composed of 220 residues of amino acid: lys6, his5, arg3, asp20, thr14, ser37, glu12, pro10, gly25 ala27 val20, met3, isoleu12, leu12, tyr9, phe2, try3 and amide ammonia16 The results indicate that protein nature and chemical properties of the alkaline protease presented here are distinct from those of alkaline proteases obtained from the other strains of B. subtilis, such as subtilopeptidase A, B and BPN’ 相似文献
89.
Daisuke Yamane-Koshizawa Sotaro Fujii Takahiro Maruno Yuji Kobayashi Masaru Yamanaka Satoshi Wakai 《Bioscience, biotechnology, and biochemistry》2018,82(2):304-311
AVCP cytochrome c′ from mesophilic Allochromatium vinosum exhibits lower stability than a thermophilic counterpart, Hydrogenophilus thermoluteolus cytochrome c′ (PHCP), in which the six specific amino acid residues that are not conserved in AVCP are responsible for its stability. Here we measured the stability of AVCP variants carrying these specific residues instead of the original AVCP ones. Among the six single AVCP variants, all of which formed a dimeric structure similar to that of the wild-type, three were successfully stabilized compared with the wild-type, while one showed lower stability than the wild-type. In addition, the most stabilized and destabilized AVCP variants could bind CO, similar to the wild-type. These results indicated that mesophilic AVCP could be stabilized through specific three mutations modeled by the thermophilic counterpart, PHCP, without changing the CO binding ability. 相似文献
90.
Zhi-Hui Su Osamu Tominaga Takeshi Ohama Eiji Kajiwara Ryoshuke Ishikawa Tokindo S. Okada Keiko Nakamura Syozo Osawa 《Journal of molecular evolution》1996,43(6):662-671
Molecular phylogenetic analyses using mitochondrial NADH dehydrogenase subunit 5 (ND5) gene sequences representing all 15 species and the majority of subspecies or races of theOhomopterus ground beetles from all over the Japanese archipelago have uncovered a remarkable evolutionary history. Clustering of the species in the molecular phylogenetic tree is linked to their geographic distribution and does not correlate with morphological characters. Taxonomically the same species or the members belonging to the same species-group fall out in more than two different places on the ND5 tree. Evidence has been presented against a possible participation of ancestral polymorphism and random lineage sorting or of hybrid individuals for the observed distribution of mitochondrial DNA haplotypes. The most plausible explanation of our results is that parallel evolution took place in different lineages. Most notably,O. dehaanii, O. yaconinus, andO. japonicus in a lineage reveal almost identical morphology with those of the same species (or subspecies) but belonging to the phylogenetically remote lineages.The nucleotide sequence data reported in this paper will appear in the DDBJ, EMBL, and GenBank nucleotide sequence databases with accession numbers D50711-DD-50733 and D87131-D87186. 相似文献