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11.
Yuzuru Matsuda Teruhiko Beppu Kei Arima 《Bioscience, biotechnology, and biochemistry》2013,77(6):1179-1186
The Oxygen activating mechanism of Fusarium lipoxygenase, a heme-containing dioxygenase, was studied. The enzyme did not require any cofactors, such as H2O2, however, both superoxide dismutase and catalase inhibited linoleate peroxidation by Fusarium lipoxygenase. A low concentration of H2O2 caused a distinct acceleration in enzymatic peroxidation. These results indicate that both O2? and H2O2 are produced as essential intermediates of oxygen activation during formation of linoleate hydroperoxides by Fusarium lipoxygenase. This peroxidation reaction was also prevented by scavengers of singlet oxygen (1O2), but not by scavengers of hydroxy 1 radical (OH). Generation of O2? in the enzyme reaction was detected by its ability to oxidize epinephrine to adrenochrome. Moreover, the rate of peroxide formation was greater in the D2O than in the H2O buffer system. These results suggest that the Haber–Weiss reaction (O2?+H2O2→OH?+OH·+1O2) is taking part in linoleate peroxidation by Fusarium lipoxygenase, and the 1O2 evolved could be responsible for the peroxidation of linoleate. H2O2 produced endogenously in the enzyme reaction might act as an activating factor for the enzyme. This possible mechanism of oxygen activation can explain the absence of a need for exogenous cofactors with Fusarium lipoxygenase in contrast to an other heme-containing dioxygenase, tryptophan pyrrolase, which requires an exogenous activating factor, such as H2O2. 相似文献
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Sea skaters, genus Halobates Eschscholtz, 1822, are the only marine insects living in mangrove beds and the tide pools of coral reefs, both of which provide dramatically variable habitats daily by virtue of tide-driven changes in surface level. Females of H. japonicus Esaki, 1924 were collected from three distinct aggregations in a single bay (24°27′5″N, 124°8′40″E) on 1–5 November 2006. Two aggregations were formed in respective tide pools of the coral reef and one was formed in the mangrove beds. Amplified fragment length polymorphism markers were used to detect the persistency of each aggregation at a mesoscale. The results suggested that H. japonicus repeatedly immigrated from outside the bay to establish a meta-population of several deme groups. Aggregations along the coastline had some persistency to the line itself and had little tendency to cross to the opposite shore, even when the distance was short. 相似文献
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Dae-In Kim Il-Kook Park Jong-Sun Kim Hidetoshi Ota Woo-Jin Choi Il-Hun Kim 《Animal cells and systems.》2019,23(1):64-70
Differential microhabitat use may be beneficial to achieving fitness in seasonally variable environmental conditions. To explore whether the microhabitat use of the nocturnal Schlegel’s Japanese gecko, Gekko japonicus, varies seasonally and depends on juvenile, male, and female reproductive groups, we investigated five categorical and five quantitative measure variables of microhabitat use in a wild population both in spring and summer. Most geckos were found on white, vertical planes of concrete and plastered brick walls. None of the categorical variables (type of location, substrate, substrate color, light source, and refuge) significantly differed according to season or group, while substrate temperature and irradiance at the location where geckos were observed and the distance from the nearest potential refuge were significantly greater in summer than in spring. The quantitative measure variables did not differ among the reproductive groups. These results suggest that G. japonicus seasonally adjusts its microhabitat use mainly in terms of quantitative measure variables rather than categorical variables. 相似文献
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目的:通过建立诱发性大鼠肝癌动物模型,研究用刺参酸性粘多糖(SJAMP)对大鼠诱发性肝癌的干预作用及免疫功能的影响。方法:将雄性Wistar大鼠50只随机均分为5个组,正常对照组、模型组和3个SJAMP干预组(A组,B组和c组),模型组和SJAMP干预组灌胃0.2%DEN生理盐水溶液以诱发肝癌,同时SJAMP干预组按照不同剂量(0.175μg/g,0.35μg/g,O.7μg/g)给予SJAMP,至16周处死大鼠,取血,无菌取脾、胸腺,计算脾指数、胸腺指数。比较各组〉3mm和〉5mm的结节数以及最大结节的体积,计算肿瘤抑制率。贴壁法纯化巨噬细胞,用中性红吞噬实验检测巨噬细胞吞噬功能,MTT法检测巨噬细胞杀伤功能。结果:SJAMP干预组〉3mm和〉5mm的结节数明显少于模型组,最大结节的平均体积明显小于模型组(P〈0.05);与模型组相比,SJAMP干预组脾指数和胸腺指数明显升高(P〈0.05),SJAMP干预组巨噬细胞吞噬能力和杀伤功能显著提高(P〈0.05)。结论:刺参酸性粘多糖对大鼠诱发性肝癌有明显的抑制作用;其机制可能是通过刺激免疫器官生长,增强机体的细胞免疫能力来实现的。 相似文献
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对中国东南沿海4个日本囊对虾地理群体16S rRNA基因片段进行了序列测定和分析.在获得的467bp 序列中,共检测到45个变异位点,多态位点比例为9.64%.具有10种单倍型,三亚群体单倍型多样性最高(0.900±0.161).各群体的核苷酸多样性(π)为0.0007~0.0082,其中三亚群体核苷酸多样性最为丰富,远高于湛江、北海和海口群体.群体间遗传分化指数(F_(st))为0.000~0.945.结合已报道的16S rRNA基因序列,构建了NJ分子系统树,中国海域日本囊对虾可分为3支.香港至台湾沿岸所有单倍型聚集为一分支,湛江、海口和北海群体内的所有单倍型聚集成另一分支,两分支分别属于已报道的变种Ⅰ和变种Ⅱ,但三亚群体内的4个单倍型单独聚集成一分支,与前两分支的核苷酸序列差异大(7.95%~8.35%),遗传分化明显,可能为一亲缘关系很远的新种(或变种).研究结果可为日本囊对虾的资源管理和遗传选育提供参考. 相似文献
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BACKGROUND AND AIMS: Lotus japonicus 'Gifu' develops multiple axillary shoots in the cotyledonary node region throughout the growth of the plant. The origin, initiation and development of these axillary meristems were investigated. METHODS: Morphological, histological and mRNA in situ analyses were done to characterize the ontogeny of cotyledonary axillary shoot meristems in Lotus. Morphological characterization of a putative Lotus shoot branching mutant (super-accessory branches) sac, is presented. KEY RESULTS: By using expression of an L. japonicus STM-like gene as a marker for meristematic tissues, it was demonstrated that groups of cells maintained in the meristematic state at the cotyledonary axil region coincide with the sites where additional axillary meristems (accessory meristems) form. A Lotus shoot branching mutant, sac, is a putative Lotus branching mutant characterized by increased proliferation of accessory shoots in all leaf axils including the cotyledons. CONCLUSION: In Lotus, axillary shoot meristems continually develop at the cotyledonary node region throughout the growth of the plant. These cotyledonary primary and accessory axillaries arise from the position of a meristematic zone of tissue at the cotyledonary node axil region. 相似文献