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81.
82.
Shima J Sakata-Tsuda Y Suzuki Y Nakajima R Watanabe H Kawamoto S Takano H 《Applied and environmental microbiology》2003,69(1):715-718
The effect of intracellular charged amino acids on freeze tolerance in dough was determined by constructing homozygous diploid arginase-deficient mutants of commercial baker's yeast. An arginase mutant accumulated higher levels of arginine and/or glutamate and showed increased leavening ability during the frozen-dough baking process, suggesting that disruption of the CAR1 gene enhances freeze tolerance. 相似文献
83.
Importance of topography and soil texture in the spatial distribution of two sympatric dipterocarp trees in a Bornean rainforest 总被引:1,自引:0,他引:1
Akira?ItohEmail author Takuo?Yamakura Tatsuhiro?Ohkubo Mamoru?Kanzaki Peter A.?Palmiotto James V.?LaFrankie Peter S.?Ashton Hua Seng?Lee 《Ecological Research》2003,18(3):307-320
Relationships between spatial distributions and site conditions, namely topography and soil texture, were analyzed for two congeneric emergent trees, Dryobalanops aromatica and Dryobalanops lanceolata (Dipterocarpaceae), in a tropical rainforest in Sarawak, East Malaysia. A 52-ha permanent plot was divided into 1300 quadrats measuring 20m×20m; for each Dryobalanops species, the number and total basal area of trees 1cm in d.b.h. were compared among groups of quadrats with different site conditions. Because spatial distributions of both Dryobalanops and site-condition variables were aggregated, Monte-Carlo permutation tests were applied to analyze the relationships. Both single and multifactor statistical tests showed that the density and basal area distributions of the two species were significantly non-random in relation to soil texture and topographic variables. D.aromatica was significantly more abundant at higher elevations, in sandy soils, and on convex and steep slopes. In contrast, D.lanceolata preferred lower elevations and less sandy soils. In the study plot, there were very few sites (3 of 1150 quadrats tested) where the models of Hayashis method predicted the co-occurrence of the two species. These results suggest that between-species differences in habitat preferences are so large that they alone explain the spatially segregated distributions of these two species within the 52-ha study plot. 相似文献
84.
Inagaki K Aki T Shiota T Kawamoto S Shigeta S Suzuki O Ono K 《Bioscience, biotechnology, and biochemistry》2003,67(2):451-454
The expression of delta6 fatty acid desaturase, previously identified, was suppressed almost completely by hyper expression of the corresponding antisense gene in a transformant of the rat hepatic cell line BRL-3A. Conversion rates of [1-14C] linoleic acid, alpha-linolenic acid, and tetracosapentaenoic acid into the respective delta6 fatty acids were equivalent to those in control cells. This finding suggested that all of these reactions were catalyzed by at least two delta6 desaturase isozymes in rat hepatocytes. 相似文献
85.
An optical bio-sniffer for ethanol was constructed by immobilizing alcohol oxidase (AOD) onto a tip of a fiber optic oxygen sensor with a tube-ring, using an oxygen sensitive ruthenium organic complex (excitation, 470 nm; fluorescent, 600 nm). A reaction unit for circulating buffer solution was applied to the tip of the device. After the experiment in the liquid phase, the sniffer-device was applied for gas analysis using a gas flow measurement system with a gas generator. The optical device was applied to detect the oxygen consumption induced by AOD enzymatic reaction with alcohol application. The sensor in the liquid phase was used to measure ethanol solution from 0.50 to 9.09 mmol/l. Then, the bio-sniffer was calibrated against ethanol vapor from 0.71 to 51.49 ppm with good gas-selectivity based on the AOD substrate specificity. The bio-sniffer with the reaction unit was also used to monitor the concentration change of gaseous ethanol by rinsing and cleaning the fiber tip and the enzyme membrane with buffer solution. 相似文献
86.
This article describes a method for preparing 2- to 50-micron-thick fresh-frozen sections from large samples and completely calcified tissue samples. In order to perform the more routine work involved, a tungsten carbide disposable blade was installed to a heavy-duty sledge cryomicrotome. An entire 10-day-old rat and bone and tooth samples from a 7-month-old rat were rapidly frozen. The frozen samples were attached to the cryomicrotome stage. The cutting surface of the samples was covered with a polyvinylidene chloride film coated with synthetic rubber cement and cut at -25 degrees C. The soft tissues and the hard tissues were satisfactorily preserved and all tissue cells were easily identifiable. Enzymatic activity in the fresh sections was much stronger than that in chemically fixed and/or decalcified sections. The sections permitted histological and histochemical studies without trouble. In addition, the sections can be used for multiple experiments such as immunohistochemistry, in situ hybridization, and electron microprobe X-ray micro-analysis. This method can be used with conventional cryomicrotome equipment. 相似文献
87.
The purpose of this study was to examine secretory activity of gonadotropin (Gn) and the responsiveness of Gn secretion to Gn-releasing hormone (GnRH) in male horseshoe bats, Rhinolophus ferrumequinum, during the annual reproductive cycle. Anterior pituitary cells were monodispersed and subjected to cell immunoblot assay for Gn. Cell blots specific for follicle stimulating hormone (FSH) or luteinizing hormone (LH) were quantified using a microscopic image analyzer. The percentages of LH- or FSH-secreting cells detected as immunoreactive cell blots were markedly increased in the spermatogenic period (summer) and decreased in the hibernation period (winter). The mean Gn secretion from individual cells and total Gn secretion per unit area of the transfer membrane also showed similar changes. The responsiveness of Gn secretion to GnRH was greater in the spermatogenic period than in other seasons. On the other hand, although the secretory activity of Gn was markedly decreased during hibernation, a stimulatory effect of GnRH on Gn secretion was observed. These findings suggest that seasonal changes in the release of Gn required for gametogenesis and gonadal steroidogenesis varied depending on the reproductive activity and seasonal changes in Gn sensitivity to stimulatory effects of GnRH due to alterations in GnRH receptor numbers and/or in postreceptor events of gonadotrophs. 相似文献
88.
In vivo gene gun-mediated DNA delivery into rodent brain tissue 总被引:1,自引:0,他引:1
Sato H Hattori S Kawamoto S Kudoh I Hayashi A Yamamoto I Yoshinari M Minami M Kanno H 《Biochemical and biophysical research communications》2000,270(1):163-170
Various types of gene transfer into live tissues have been tried. However, in vivo gene transfer into brain tissue or neuronal cells without virus vector has required a great effort. Particle-mediated gene transfer into live brain tissue was thought to be impossible because of its fragility and the mechanical problem of a previous type of gene gun. In addition, particle-mediated DNA transfer into monolayer-cultured cells without mechanical damage has been difficult. We successfully transferred DNA into rodent live brain tissue and also into monolayer-cultured cells without mechanical damage by using a new type of gene gun and also confirmed gene expression in the brain. This new method represents another variation of gene transfer into the brain. 相似文献
89.
Kawamoto Y Nakamura Y Naito Y Torii Y Kumagai T Osawa T Ohigashi H Satoh K Imagawa M Uchida K 《The Journal of biological chemistry》2000,275(15):11291-11299
90.