The mechanism by which mouse spermatozoa are injured during freezing   总被引：1，自引：0，他引：1  

Jin B  Yamasaki C  Yamada N  Seki S  Valdez DM  Kasai M  Edashige K 《The Journal of reproduction and development》2008,54(4):265-269

To improve the cryopreservation protocol for mouse sperm, we attempted to estimate the type and extent of cryoinjury at various steps of the process. First, we demonstrated that mouse sperm are sensitive to chilling at -15 C and that the sensitivity is dependent on the length of exposure. To estimate cryoinjuries, sperm suspensions were ice-seeded at -5 or -15 C, frozen with liquid nitrogen (LN(2)) gas and then frozen in LN(2). In one experiment, sperm seeded at -5 C were cooled slowly to -15 C before deep freezing. At various steps of the cryopreservation process, the sperm were warmed and their viability was assessed based on motility and the integrities of the plasma membrane and acrosome. The motility of frozen-thawed sperm was higher on seeding at -5 C (28%) than at -15 C (9%). The motility did not decrease when the sample was transferred from LN(2) gas to LN(2). To estimate cryoinjury of sperm, we presumed the viability of frozen sperm to be decreased by chilling, hypertonic stress and formation of intracellular ice. When the sperm suspension was cooled and seeded at -5 C, the motility decreased by 25% due to hypertonic stress. When the sperm were cooled in LN(2) gas, the motility decreased by 17% with the formation of intracellular ice. When the sperm were cooled to -15 C, the motility decreased by 51% from chilling. After seeding, the motility decreased by 18% due to formation of intracellular ice and by 7% due to hypertonic stress. Considering the results, it would be preferable to seed samples at a higher temperature to prevent intracellular ice from forming and to cool seeded samples rapidly enough to minimize chilling injury and hypertonic stress, but not too rapidly to allow intracellular ice to form.  相似文献   

蛋鸡周龄和午后添加贝壳粉对蛋壳品质的影响   总被引：6，自引：1，他引：5  

潘雪男  出云章久  笠井浩司 《上海农业学报》2000,16(1):33-37

经过两个年龄段４个试验组的蛋鸡研究结果表明：（１）随着其的增长蛋有增厚的趋势,而蛋壳强度却不产产;（２）午后添加贝粉对蛋壳厚度的影响因年龄而异,且可缓解因年龄增长而蛋壳强度逐步减弱的程度;（３）蛋重,在同一产蛋日中以上午９：００￣１１：００时产的蛋为最,但其壳厚和强度均不如其它时间段内所产的蛋;（４）在同龄蛋鸡群间,产蛋率高的群所产蛋的壳强度亦高,但未发现两者的相关性。  相似文献   

Gastroprotective effect of red pigments in black chokeberry fruit (Aronia melanocarpa Elliot) on acute gastric hemorrhagic lesions in rats     

Matsumoto M  Hara H  Chiji H  Kasai T 《Journal of agricultural and food chemistry》2004,52(8):2226-2229

It has been reported that the fruits and leaves of berries such as the blackberry, raspberry, and strawberry contain a high level of scavenging activity for chemically generated active oxygen species. This study investigated the antioxidative activities of black chokeberry fruit (Aronia melanocarpa Elliot) both in vitro and in vivo using the DPPH stable radical and rats with ethanol-induced gastric injury, respectively. The red pigment fraction of the black chokeberry contained three main components, one of which was identified as cyanidin 3-O-beta-glucoside by HPLC analysis and (1)H NMR. The black chokeberry red pigment fraction scavenged >44% of DPPH radicals at a concentration of 25 microg/mL compared to the control solution. The black chokeberry extract and its hydrolysate administrated at 2 g/kg of body weight each had nearly the same protective effect as quercetin administrated at 100 mg/kg of body weight in suppressing the area of gastric mucosal damage caused by the subsequent application of ethanol to <30% compared to the control group. The black chokeberry red pigment fraction had a similarly significant protective effect on gastric mucosa in a dose-dependent manner when administered at 30-300 mg/kg of body weight, and the administration of 30 mg/kg of body weight could suppress ethanol-induced gastric mucosal damage by approximately 50% (ID(50) = 30 mg/kg of body weight).  相似文献   

Extraction of soybean oil from single cells     

Kasai N  Imashiro Y  Morita N 《Journal of agricultural and food chemistry》2003,51(21):6217-6222

Single cells prepared from autoclaved soybeans and cellulase treatment of the cells were effective in digesting the cell walls of and extracting the oil from soybeans. The first cell wall of the soybean single cell was completely removed using cellulases; the thin and transparent second cell wall of the cell was swollen. Oil in the cell formed spherical or hemispherical oil drops, and oil leaking from the oil bodies was observed. The oil was almost retained within the second cell wall. Water-extractable substances were obtained at approximately >60% of the weight. Flotation of oil drops by centrifugation was easily done. Ambient n-hexane extraction was also possible; however, residual oil remained in the oil bodies. Protease or peptidase digested the structure of the oil bodies; however, separation of the oil and the hydrolysates was impossible. The oil from the oil bodies was obtained effectively (>85%) by pressing the single cells and/or cellulase-treated single cells.  相似文献   

Buffers,barriers and blankets: The (dis)connectivity of catchment-scale sediment cascades   总被引：2，自引：0，他引：2  

Kirstie A. Fryirs  Gary J. Brierley  Nicholas J. Preston  Mio Kasai 《CATENA》2007

Catchment configuration and the nature of connectivity within and between landscape compartments affect the operation of sediment cascades and geomorphic responses to disturbance events of differing magnitude and frequency. This paper introduces the concept of landform impediments, termed buffers, barriers and blankets, that impede sediment conveyance by limiting the connectivity between landscape compartments. Buffers restrict sediment delivery to channels, barriers inhibit sediment movement along channels, and blankets drape channel or floodplain surfaces affecting the accessibility of sediment to entrainment. These features operate as a series of switches which turn on/off processes of sediment delivery, determining the effective catchment area at any given time. Using previously documented examples, the role of these features in affecting the operation of sediment cascades in a low relief, passive landscape setting such as the Australian landmass is contrasted to examples from high relief, uplifting settings in New Zealand. The Australian examples are further explored by examining how changes to landscape connectivity brought about by human disturbance since European settlement have impacted upon landscape sensitivity and prospects for river recovery. This approach to analysis of impediments to sediment conveyance is generic and can be applied in any environmental setting.  相似文献   

Synergetic deodorant effect and antibacterial activity of composite paper containing waste tea leaves     

Tetsuya Takahashi  Yuji Aso  Wakako Kasai  Tetsuo Kondo 《Journal of Wood Science》2011,57(4):308-316

Composite paper containing waste tea leaves was prepared to investigate the effective utilization of waste tea leaves as deodorant material. Paper containing waste green tea leaves did not have increased deodorizing ability compared with controls either against acidic odors such as hydrogen sulfide and acetic acid gases or against neutral odors such as formaldehyde and acetaldehyde gases. In contrast, the paper had excellent deodorizing ability against basic odors such as ammonia and trimethylamine gases. It was observed during additional tests conducted on paper samples containing 60 wt% waste leaves of oolong tea, black tea, pu-erh tea, or hojicha, that all the samples reduced the ammonia concentration to below 1 ppm, which is the threshold concentration for olfactory recognition, within 30 min. Further, paper containing waste green tea leaves was found to decrease the odor residual rate to 5.1% in 30 min even for a waste tea leaf content of 10 wt%. The excellent deodorizing ability of the paper could be attributed to the chemical reactions between odorous substances and the catechins found in tea leaves. After the deodorization of ammonia, paper containing waste green tea leaves was found to have increased antibacterial activity against Staphylococcus aureus.  相似文献   

ROS-generating mitochondrial DNA mutations can regulate tumor cell metastasis     

Ishikawa K  Takenaga K  Akimoto M  Koshikawa N  Yamaguchi A  Imanishi H  Nakada K  Honma Y  Hayashi J 《Science (New York, N.Y.)》2008,320(5876):661-664

Mutations in mitochondrial DNA (mtDNA) occur at high frequency in human tumors, but whether these mutations alter tumor cell behavior has been unclear. We used cytoplasmic hybrid (cybrid) technology to replace the endogenous mtDNA in a mouse tumor cell line that was poorly metastatic with mtDNA from a cell line that was highly metastatic, and vice versa. Using assays of metastasis in mice, we found that the recipient tumor cells acquired the metastatic potential of the transferred mtDNA. The mtDNA conferring high metastatic potential contained G13997A and 13885insC mutations in the gene encoding NADH (reduced form of nicotinamide adenine dinucleotide) dehydrogenase subunit 6 (ND6). These mutations produced a deficiency in respiratory complex I activity and were associated with overproduction of reactive oxygen species (ROS). Pretreatment of the highly metastatic tumor cells with ROS scavengers suppressed their metastatic potential in mice. These results indicate that mtDNA mutations can contribute to tumor progression by enhancing the metastatic potential of tumor cells.  相似文献   

Incorporation of phosphate-32P into phospholipids by illuminated chloroplasts     

Ryuichiro Deura  Zenzaburo Kasai 《Soil Science and Plant Nutrition》2013,59(4):162-165

Most of leaf lipids localize in the chloroplasts and are particulary concentrated in the lamellae in which photophosphorylation is performed (1). Using animal mitochondria, GARBUS et al (2), Galliard and Hawthorne (3) studied the incorporation of ³²Pi into lipids. Their results suggest that initial rapid incorporation of ³²Pi occurred with the phosphatidyl inositols.  相似文献   

Importance of estuarine nursery areas for the adult population of the temperate seabass Lateolabrax japonicus,as revealed by otolith Sr:Ca ratios          下载免费PDF全文

Taiki Fuji  Akihide Kasai  Masahiro Ueno  Yoh Yamashita 《Fisheries Oceanography》2016,25(4):448-456

Otolith Sr:Ca ratios were used to evaluate the contribution of estuarine nursery areas to the temperate seabass (Lateolabrax japonicus) population in Tango Bay, the Sea of Japan. Otolith Sr:Ca ratios of juveniles collected from freshwater, brackish and coastal areas were analysed to determine a criterion for distinguishing whether individuals used estuarine or coastal areas as nurseries. Otolith Sr:Ca ratios of adult seabass collected around Tango Bay were also analysed to detect the records of salinity that juveniles experienced and to estimate the contribution of each habitat. Sr:Ca ratios of the edges of otoliths of juveniles from freshwater areas were 2.4 × 10^?3 in average, which were significantly lower than those of juveniles collected from a coastal area (4.9 × 10^?3 in average) owing to differences in salinity conditions among these areas. Based on the threshold criterion determined by this difference, 39 out of 107 (36%) adult seabass were estimated to have used the estuary as a nursery during their juvenile stage according to their Sr:Ca chronologies. Despite the small area covered by estuarine nurseries compared with coastal waters, the Yura River estuary contributed considerably to the adult seabass population. This indicates estuaries play an important role as nurseries for seabass juveniles, and it should be noted that the estuaries are important nurseries to conserve the stocks of coastal fishes.  相似文献   

Identification of Antiviral Agents Targeting Hepatitis B Virus Promoter from Extracts of Indonesian Marine Organisms by a Novel Cell-Based Screening Assay     

Atsuya Yamashita  Yuusuke Fujimoto  Mayumi Tamaki  Andi Setiawan  Tomohisa Tanaka  Kaori Okuyama-Dobashi  Hirotake Kasai  Koichi Watashi  Takaji Wakita  Masaaki Toyama  Masanori Baba  Nicole J. de Voogd  Shinya Maekawa  Nobuyuki Enomoto  Junichi Tanaka  Kohji Moriishi 《Marine drugs》2015,13(11):6759-6773

The current treatments of chronic hepatitis B (CHB) face a limited choice of vaccine, antibody and antiviral agents. The development of additional antiviral agents is still needed for improvement of CHB therapy. In this study, we established a screening system in order to identify compounds inhibiting the core promoter activity of hepatitis B virus (HBV). We prepared 80 extracts of marine organisms from the coral reefs of Indonesia and screened them by using this system. Eventually, two extracts showed high inhibitory activity (>95%) and low cytotoxicity (66% to 77%). Solvent fractionation, column chromatography and NMR analysis revealed that 3,5-dibromo-2-(2,4-dibromophenoxy)-phenol (compound 1) and 3,4,5-tribromo-2-(2,4-dibromophenoxy)-phenol (compound 2), which are classified as polybrominated diphenyl ethers (PBDEs), were identified as anti-HBV agents in the extracts. Compounds 1 and 2 inhibited HBV core promoter activity as well as HBV production from HepG2.2.15.7 cells in a dose-dependent manner. The EC₅₀ values of compounds 1 and 2 were 0.23 and 0.80 µM, respectively, while selectivity indexes of compound 1 and 2 were 18.2 and 12.8, respectively. These results suggest that our cell-based HBV core promoter assay system is useful to determine anti-HBV compounds, and that two PBDE compounds are expected to be candidates of lead compounds for the development of anti-HBV drugs.  相似文献