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        검색결과 17

        2.
        2016.04 구독 인증기관·개인회원 무료
        Brachymystax lenok tsinlingensis (family Salmonidae), cold freshwater fish, is endemic to Asia. This species is currently distributed throughout Russia, Mongolia, China and the Korean Peninsula. B. lenok tsinlingensis in South Korea was severely affected by anthropogenic activities such as habitat destruction, agricultural run-off and water pollution, and hence this fish has recently been dramatically decreased in its population sizes and become now critically endangered. To recover the number of individuals of B. lenok tsinlingensis, stocking or translocation programs have been conducted continuously by local governments since 1970s. However, these programs made little effort to clarify populations that may have originated from stocked, translocated or introduced fish. An understanding of genetic characteristics of endangered populations is critical to develop effective conservation and restoration plans especially because genetic diversity ensues their future fate. Therefore, we assessed the “conservation status” of this species by estimating the level of genetic diversity and genetic structure among ten geographic populations including restored populations via reinforcement and supplementation. Also, we aimed to trace the genetic origins of the newly translocated population (Chiak) through a restoration practice program. Moreover, we inferred the phylogenetic relationships among Korean lenok populations as well as across the Northeast Asia. Two hundred eighteen individuals of B. lenok tsinlingensis were sampled from ten localities (Yanggu, Injae, Seorak, Bangtae and Hongcheon: North Han River basin; Pyeongchang, Chiak and Jeongseon: South Han River basin; Taebaek and Bonghwa: Nakdong River basin in South Korea). Based on mitochondrial DNA (mtDNA) control region and eight nuclear microsatellite loci, we found extremely low levels of within-population genetic diversity, which suggests small effective population sizes (Ne) within populations. For mtDNA control region, each population housed one, or at most, two haplotypes that are restricted to the respective localities, meaning that these ‘genetically unique’ lineages will be lost permanently if the local populations undergo extinction. The overall values of haplotype diversity (h) and nucleotide diversity (π) for the entire Korean population were 0.703 ± 0.024 and 0.021 ± 0.010, respectively. In the case of microsatellites, average number of alleles across the eight loci for the entire population was 9.1 and allelic richness (AR) per population ranged from 2.375 to 4.144 (mean = 3.104). The values of observed heterozygosity (HO) and expected heterozygosity (HE) were similar to each other [HO: 0.400 ~ 0.590 (mean = 0.518); HE: 0.407 ~ 0.608 (mean = 0.504)]. The inbreeding coefficient (FIS) values were generally low, ranging from 0.048 to 0.279. Consequently, the majority of the populations (except Yanggu and Pyeongchang) were not significantly deviated from Hardy-Weinberg equilibrium (HWE), suggesting random mating at these loci tested. In addition, we found that Korean lenok populations were significantly genetically isolated from each other, with private mtDNA haplotypes and microsatellite alleles, indicating limited gene flow among populations, strong effects of genetic drift due to small Ne, or a combination of both. The Mantel test of microsatellites revealed a significant correlation (r = 0.414, P = 0.04) between genetic and geographic distances for pairwise comparisons among the ten populations, while that of mtDNA showed a lack of correlation. Given the shared identical mtDNA haplotype and similar microsatellite allelic distributions between Chiak and Hongcheon populations, we suggest that the restored (introduced) Chiak population would be inferred to be genetically originated from Hongcheon population. Phylogenetic relationships among Northeast Asian populations showed that South Korean lineages have more recently diverged from China (Yellow River), than between North Korea and Russia. Although the phylogenetic relationship would be expected to be associated with geography, South-North Korea and China populations with a similar latitude was more phylogenetically closely related. These findings may suggest a possible scenario for the historical movements of B. lenok tsinlingensis in Northeast Asia during Last Glacial Maximum (LGM). It would be supported by the line of evidence that most lenok populations migrated to southward from Northern Asia such as Russia and Mongolia during LGM because the Korean Peninsula was landlocked as inland epoch and functioned as a southern shelter with Yellow River. For this reason, the Korean Peninsula is suggested to be an important geographical region for better understanding phylogenetic relationships and evolutionary histories of B. lenok tsinlingensis across the Northeast Asia. Despite large efforts made to develop several restoration programs in South Korea for B. lenok tsinlingensis, it is still unknown whether these past restoration efforts were successful or fruitless, mainly because of little attention paid to post-restoration monitoring research. Hence, there was a lack of their published official records. In the future, conservation and restoration projects of the Korean lenok populations should consider the genetic data for a better understanding of their ecological and evolutionary trajectories. And finally, we hope that our findings here can help inform on the future effective conservation and restoration plans for B. lenok tsinlingensis populatio ns in South Korea.
        4.
        2007.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        10.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        12.
        2005.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        13.
        2005.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        14.
        2016.05 서비스 종료(열람 제한)
        Background : The purpose of this study was to big strong and root in the disease, many high quality seed of Lithospermum erythrorhizon selection by fostering, expanding the spread on a farm and Hongju subsistence production base and raw materials medicines of sources deployment for process is to contribute to increasing farm income. Methods and Results : Collected variety into the chemical mutation breeding method, Jecheon of Chungbuk, was conducted in 2001. In 2002 and 2003, two~ three individual selection in 2005 as it produces the 24 individual in 2004. From 2006 to 2010, pure line isolation as it cultivated and one foundation group. Promising in 2011, select one system. Replicated yield trial for two years beginning in 2012 a result of the stem length, providing high -quality “No. 1, Jeollanam-do” majority by assigning system name. Naju, Jangheung-gun, local excellence by implementing a local adaptability test recognized in two years. To breed a new variety named as a dwelling “ Daehong” of Lithospermum erythrorhizon the review by fostering december 2014 to be registered. Conclusions : Leaf type is the broad lancet, flowering time is new variety six days than Jecheon native variety fasted. New variety of stem length and stem thickness are check variety (87cm, 8.25mm) of 9cm tall and 0.6mm thick. Seed yields has native variety as much as 81 % compared to the many into 45.6 kg/10a. The shikonin contents of roots was 1.3 times higher compared to check variety (447 ㎍ / g). The dried root yields of the new variety are 221kg/10a a many native variety than 50%.
        15.
        2013.03 서비스 종료(열람 제한)
        Cerebral infarction is one of the leading causes of death worldwide and the most common cause of death from a singledisease in South Korea. Each year, 795,000 people in the U.S. experience a new or recurrent stroke. Approximately 15-30% of cerebral infarctions are of embolic origin related to cardiac abnormalities. Because determination of the etiology of cerebral infarction is crucial to acute management and future prevention, clinicians should pay attention to finding the cardiac source of embolism in patients with cerebral infarction. We report on a case of cerebral infarction by a small papillary fibroelastoma on the mitral valve. The patient was treated with open heart surgery and closure of the patent foramen ovale to prevent further embolic events.