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81.
To elucidate the regulatory mechanisms of carotenogenesis in Japanese apricot (Prunus mume Siebold & Zucc.), the relationships between carotenoid accumulation and the expression of the carotenogenic genes, phytoene synthase (PmPSY-1), phytoene desaturase (PmPDS), zeta-carotene desaturase (PmZDS), lycopene beta-cyclase (PmLCYb), lycopene epsilon-cyclase (PmLCYe), beta-carotene hydroxylase (PmHYb), and zeaxanthin epoxidase (PmZEP), were analyzed in two cultivars with different ripening traits, 'Orihime' and 'Nanko.' In 'Orihime' fruits, large amounts of carotenoids accumulated on the tree, concomitant with the induction of PmPSY-1 and the downstream carotenogenic genes PmLCYb, PmHYb, and PmZEP. In 'Nanko' fruits, carotenoids accumulated mainly after harvest, correlating with an appreciable induction of PmPSY-1 expression, but the downstream genes were not notably induced, which may explain the lower total carotenoid content in 'Nanko' than in 'Orihime.' In both cultivars, a decrease in PmLCYe expression and increased or constant PmLCYb expression could cause the metabolic shift from beta,epsilon-carotenoid synthesis to beta,beta-carotenoid synthesis that occurs as ripening approaches. Next, the effects of ethylene on the expression of PmPSY-1 and carotenoid accumulation were investigated in 'Nanko' fruits treated with propylene or 1-methylcyclopropene (1-MCP). Propylene treatment induced both ethylene production and carotenoid accumulation. PmPSY-1 was constitutively expressed, but propylene treatment accelerated its induction. 1-MCP treatment caused a slight inhibition of carotenoid accumulation along with the repression, although not complete, of PmPSY-1. Collectively, although PmPSY-1 expression was not exclusively regulated by ethylene, both the notable induction of PmPSY-1 accelerated by ethylene and the subsequent induction of the downstream carotenogenic genes, especially PmLCYb, could be necessary for the massive carotenoid accumulation that occurs during ripening. Furthermore, the switch from PmLCYe expression to PmLCYb expression could cause beta,beta-carotenoid accumulation in both Japanese apricot cultivars.  相似文献   
82.
Land development has caused runoff of red soil into the ocean on the north side of Okinawa Island, Japan. In an attempt to clarify the impacts of this “red soil pollution” on the oxidizing power of seawater, we studied the formation of hydroxyl radical (?OH), the most potent oxidant in the environment, in red soil-polluted waters using a 313-nm monochromatic light. ?OH was photochemically formed in the red soil-polluted water samples, and the formation rates of ?OH decreased as salinity increased, i.e., as red soil-polluted river water gets mixed with seawater. The photo-formation rates of ?OH showed good correlations with dissolved Fe concentrations (R 2?=?0.96) and [NO2 ?]?+?[NO3 ?] concentrations (R 2?=?0.87), while a negative and weak correlation was found with dissolved organic carbon concentrations (R?=??0.78). Theoretical calculation showed that direct photolysis of NO3 ?, Fe(OH)2+, and hydrogen peroxide all together accounted for less than 10% of the observed ?OH formation in the red soil-polluted waters. Comparison between filtered and unfiltered samples showed that red soil particles were not the main sources of ?OH, and the photolysis of NO2 ? could account for at most 78% of the observed ?OH formation rates. We found that the Fenton’s reaction (a reaction between Fe(II) and H2O2) could possibly account for the observed formation of ?OH in the red soil-polluted waters.  相似文献   
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Culicoides brevitarsis transmits important ruminant arboviruses, such as Akabane, Aino and bluetongue viruses. The presence of this species has so far been recognized primarily in Okinawa, the southernmost prefecture of Japan. In entomological surveys in 2008 and 2009, C. brevitarsis was collected at 8 sites throughout Nagasaki, Kumamoto and Kagoshima Prefectures. The collection sites are all located near pastures, where the larvae of C. brevitarsis can grow in cattle dung left in the field. C. brevitarsis was confirmed at the same sites in two consecutive years, suggesting that it overwinters in Kyushu. Given the risk of arbovirus transmission, the ecology of C. brevitarsis in Japan, such as its distribution range, seasonal abundance and larval breeding sites, should be investigated in more detail.  相似文献   
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We investigated the energy metabolism in roots of flooded Melaleuca cajuputi Powell, a tropical flood-tolerant tree species, by measuring adenylate concentrations and activities of glycolytic and fermentative enzymes under flooded conditions. Adenylate energy charge (AEC) decreased slightly to 0.72 on the second day of flooding and recovered to around 0.8 by the fourth day of flooding. Activities of pyruvate decarboxylase (EC 4.1.1.1) and alcohol dehydrogenase (EC 1.1.1.1) increased initially and then decreased to the control level after 14 days of flooding. On the other hand, activities of pyruvate kinase (EC 2.7.1.40), phosphoenolpyruvate phosphatase (EC 3.1.3.2), and a series of phosphoenolpyruvate carboxylase (EC 4.1.1.31), malate dehydrogenase (EC 1.1.1.37), and NADP dependent malic enzyme (EC 1.1.1.40), which can convert PEP into pyruvate, were not induced in flooded roots throughout the experiment. These results suggest that neither the downstream reactions of glycolysis nor ATP production via glycolysis was enhanced by flooding, whereas alcohol fermentation was enhanced. With the low ATP yield of the glycolysis–alcohol fermentation pathway and no induction of glycolytic enzymes, the glycolysis–alcohol fermentation pathway itself contributes little to ATP production in flooded roots of M. cajuputi. These physiological responses of M. cajuputi to flooding may have the advantages of surviving flooded conditions because they can avoid exhaustion of sugar and accumulation of ethanol, a toxic end product of alcohol fermentation.  相似文献   
89.
The rice cultivar ASD7 (Oryza sativa L. ssp. indica) is resistant to the brown planthopper (BPH; Nilaparvata lugens Stål) and the green leafhopper (Nephotettix virescens Distant). Here, we analyzed multiple genetic resistance to BPH and the green rice leafhopper (GRH; Nephotettix cincticeps Uhler). Using two independent F2 populations derived from a cross between ASD7 and Taichung 65 (Oryza sativa ssp. japonica), we detected two QTLs (qBPH6 and qBPH12) for resistance to BPH and one QTL (qGRH5) for resistance to GRH. Linkage analysis in BC2F3 populations revealed that qBPH12 controlled resistance to BPH and co-segregated with SSR markers RM28466 and RM7376 in plants homozygous for the ASD7 allele at qBPH6. Plants homozygous for the ASD7 alleles at both QTLs showed a much faster antibiosis response to BPH than plants homozygous at only one of these QTLs. It revealed that epistatic interaction between qBPH6 and qBPH12 is the basis of resistance to BPH in ASD7. In addition, qGRH5 controlled resistance to GRH and co-segregated with SSR markers RM6082 and RM3381. qGRH5 is identical to GRH1. Thus, we clarified the genetic basis of multiple resistance of ASD7 to BPH and GRH.  相似文献   
90.
ABSTRACT: The effects of trimethylamine- N -oxide (TMAO) on the urea-resistibility of requiem shark myofibrils were investigated, using Ca2+- and Mg2+-ATPase activities as a parameter. Both activities were hardly changed or activated up to 0.6 M urea. In contrast, the two activities both decreased to less than 50% in the presence of TMAO up to 0.5 M. When measured at a 2 : 1 molar ratio of urea and TMAO, Ca2+- and Mg2+-ATPase activities were similar to those in the presence of TMAO alone, indicating that TMAO reduced the urea-resistibility of myofibrils. Myosin, the most abundant protein in myofibrils, from requiem shark exhibited the effects of urea and TMAO on its Ca2+-ATPase activity, which was primarily similar to those of myofibrils. However, Ca2+-ATPase activities in the coexistence of urea and TMAO for actomyosin reconstituted from requiem shark myosin and chicken F-actin were approximately average of those measured independently in the presence of either urea or TMAO alone. Carp myofibrils, reconstituted actomyosin and myosin, which were used as teleost references, all showed a tendency in the effects of urea and TMAO on Ca2+-ATPase activities that was similar to those of requiem shark counterparts.  相似文献   
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