• Title/Summary/Keyword: symbiotic relationships

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Phylogenetic relationships of Armillaria spp. on the basis of ITS region sequences (rDNA의 ITS 부위 염기서열 분석에 의한 Armillaria 속 수집 균주의 유전적인 유연관계 분석)

  • Oh, Jin-A;Lee, Chan-Jung;Cheong, Jong-Chun;Yoo, Young-Bok
    • Journal of Mushroom
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    • v.10 no.3
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    • pp.143-149
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    • 2012
  • Armillaria spp are well known as a symbiotic fungus with Gastrodia elata. This study was carried out to identify and analyze the genetic relationships among 83 strains of Armillaria spp.. The amplified internal transcribed spacer(ITS) region of the rDNA was about 500~750 bp long and identified by 9 strains; A. mellea, A. tabescens, A. ostoyae, A. gallica, A. novae-zenlandia, A. cepistipes, A. nabsnona, A. gemina, A. sinapina. Sequence analysis showed that 52% of strains were different with original identification. A. gallica, A. cepistipes and A. gemina were so close phylogenetic relationship, that was difficult to classify using ITS region. In A. gallica, 12 strains including ASI10104 were showed a close phylogenetic relationship with A. gallica, A. cepistipes and A. gemina. ASI10017 and ASI10114 were classified as the A. sinapina group, ASI10045 was the A. borealis group, ASI10002 and ASI10025 were the A. ostoyae group. So more studies need for more accurate identification and determine the phylogenetic relationships of Armillaria spp.

Business Relationships and Structural Bonding: A Study of American Metal Industry (산업재 거래관계와 구조적 결합: 미국 금속산업의 분석 연구)

  • Han, Sang-Lin;Kim, Yun-Tae;Oh, Chang-Yeob;Chung, Jae-Moon
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.3
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    • pp.115-132
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    • 2008
  • Metal industry is one of the most representative heavy industries and the median sales volume of steel and nonferrous metal companies is over one billion dollars in the case America [Forbes 2006]. As seen in the recent business market situation, an increasing number of industrial manufacturers and suppliers are moving from adversarial to cooperative exchange attitudes that support the long-term relationships with their customers. This article presents the results of an empirical study of the antecedent factors of business relationships in metal industry of the United States. Commitment has been reviewed as a significant and critical variable in research on inter-organizational relationships (Hong et al. 2007, Kim et al. 2007). The future stability of any buyer-seller relationship depends upon the commitment made by the interactants to their relationship. Commitment, according to Dwyer et al. [1987], refers to "an implicit or explicit pledge of relational continuity between exchange partners" and they consider commitment to be the most advanced phase of buyer-seller exchange relationship. Bonds are made because the members need their partners in order to do something and this integration on a task basis can be either symbiotic or cooperative (Svensson 2008). To the extent that members seek the same or mutually supporting ends, there will be strong bonds among them. In other words, the principle that affects the strength of bonds is 'economy of decision making' [Turner 1970]. These bonds provide an important idea to study the causes of business long-term relationships in a sense that organizations can be mutually bonded by a common interest in the economic matters. Recently, the framework of structural bonding has been used to study the buyer-seller relationships in industrial marketing [Han and Sung 2008, Williams et al. 1998, Wilson 1995] in that this structural bonding is a crucial part of the theoretical justification for distinguishing discrete transactions from ongoing long-term relationships. The major antecedent factors of buyer commitment such as technology, CLalt, transaction-specific assets, and importance were identified and explored from the perspective of structural bonding. Research hypotheses were developed and tested by using survey data from the middle managers in the metal industry. H1: Level of technology of the relationship partner is positively related to the level of structural bonding between the buyer and the seller. H2: Comparison level of alternatives is negatively related to the level of structural bonding between the buyer and the seller. H3: Amount of the transaction-specific assets is positively related to the level of structural bonding between the buyer and the seller. H4: Importance of the relationship partner is positively related to the level of structural bonding between the buyer and the seller. H5: Level of structural bonding is positively related to the level of commitment to the relationship. To examine the major antecedent factors of industrial buyer's structural bonding and long-term relationship, questionnaire was prepared, mailed out to the sample of 400 purchasing managers of the US metal industry (SIC codes 33 and 34). After a follow-up request, 139 informants returnedthe questionnaires, resulting in a response rate of 35 percent. 134 responses were used in the final analysis after dropping 5 incomplete questionnaires. All measures were analyzed for reliability and validity following the guidelines offered by Churchill [1979] and Anderson and Gerbing [1988]., the results of fitting the model to the data indicated that the hypothesized model provides a good fit to the data. Goodness-of-fit index (GFI = 0.94) and other indices ( chi-square = 78.02 with p-value = 0.13, Adjusted GFI = 0.90, Normed Fit Index = 0.92) indicated that a major proportion of variances and covariances in the data was accounted for by the model as a whole, and all the parameter estimates showed statistical significance as evidenced by large t-values. All the factor loadings were significantly different from zero. On these grounds we judged the hypothesized model to be a reasonable representation of the data. The results from the present study suggest several implications for buyer-seller relationships. Theoretically, we attempted to conceptualize the antecedent factors of buyer-seller long-term relationships from the perspective of structural bondingin metal industry. The four underlying determinants (i.e. technology, CLalt, transaction-specific assets, and importance) of structural bonding are very critical variables of buyer-seller long-term business relationships. Our model of structural bonding makes an attempt to systematically examine the relationship between the antecedent factors of structural bonding and long-term commitment. Managerially, this research provides industrial purchasing managers with a good framework to assess the interaction processes with their partners and, ability to position their business relationships from the perspective of structural bonding. In other words, based on those underlying variables, industrial purchasing managers can determine the strength of the company's relationships with the key suppliers and its state of preparation to be a successful partner with those suppliers. Both the supplying and customer companies can also benefit by using the concept of 'structural bonding' and evaluating their relationships with key business partners from the structural point of view. In general, the results indicate that structural bonding gives a critical impact on the level of relationship commitment. Managerial implications and limitations of the study are also discussed.

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Interaction of Escherichia coli K1 and K5 with Acanthamoeba casfellanii Trophozoites and Cysts

  • Matin, Abdul;Jung, Suk-Yul
    • Parasites, Hosts and Diseases
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    • v.49 no.4
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    • pp.349-356
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    • 2011
  • The existence of symbiotic relationships between Acanthamoeba and a variety of bacteria is well-documented. However, the ability of Acanthamoeba interacting with host bacterial pathogens has gained particular attention. Here, to understand the interactions of Escherichia coli K1 and E. coli K5 strains with Acanthamoeba castellanii trophozoites and cysts, association assay, invasion assay, survival assay, and the measurement of bacterial numbers from cysts were performed, and nonpathogenic E. coli K12 was also applied. The association ratio of E. coli K1 with A. castellanii was 4.3 cfu per amoeba for 1 hr but E. coli K5 with A. castellanii was 1 cfu per amoeba for 1 hr. By invasion and survival assays, E. coli K5 was recovered less than E. coli K1 but still alive inside A. castellanii. E. coli K1 and K5 survived and multiplied intracellularly in A. castellanii. The survival assay was performed under a favourable condition for 22 hr and 43 hr with the encystment of A. castellanii. Under the favourable condition for the transformation of trophozoites into cysts, E. coli K5 multiplied significantly. Moreover, the pathogenic potential of E. coli K1 from A. castellanii cysts exhibited no changes as compared with E. coli K1 from A. castellanii trophozoites. E. coli K5 was multiplied in A. castellanii trophozoites and survived in A. castellanii cysts. Therefore, this study suggests that E. coli K5 can use A. castellanii as a reservoir host or a vector for the bacterial transmission.

Role of Lectins in Host Plant-Rhizobium Interactions (근류균과 숙주식물의 상호작용에 관한 렉틴의 역할)

  • Chang Moo Ung;Jeune Kyung Hee;Park Won Hark
    • Korean journal of applied entomology
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    • v.22 no.4 s.57
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    • pp.293-299
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    • 1983
  • Experiments were carried out to elucidate the specific interactions between host plant, Phaseolus vulgaris, and symbiotic bacteria, Rhizobium Phaseoli. Purified P. vulgaris lectins and six species of cultured Rhizobium were subjected to agglutination test. Lectins from bean and R. phaseoli showed relatively high agglutination activity indicating that host plant lectins recognize carbohydrate moieties on the compatible Rhizobium cell surface. The specific carbohydrate receptors for binding of the lectins on the cell surface of R. phaseoli were found as mannose and galactose. The minimum concentration of sugars for the inhibition was 6.25mM. The lectin content of cultured plant roots was measured after germination and was maximum in 5-day seedlings. The nodulation was competitively inhibited by lectins for the plants cultured with Rhizobium cells. By immunochemical studies, there was some relationship in antigenic determinants between R. phaseoli and R. japonicum but no relationships were observed with other Rhizobium species. The results suggest that the infection by rhizobia to the roots of leguminous plants may be caused by the specific interaction of lectins with rhizobia.

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Yeast Associated with the Ambrosia Beetle, Platypus koryoensis, the Pest of Oak Trees in Korea

  • Yun, Yeo Hong;Suh, Dong Yeon;Yoo, Hun Dal;Oh, Man Hwan;Kim, Seong Hwan
    • Mycobiology
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    • v.43 no.4
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    • pp.458-466
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    • 2015
  • Oak tree death caused by symbiosis of an ambrosia beetle, Platypus koryoensis, and an ophiostomatoid filamentous fungus, Raffaelea quercus-mongolicae, has been a nationwide problem in Korea since 2004. In this study, we surveyed the yeast species associated with P. koryoensis to better understand the diversity of fungal associates of the beetle pest. In 2009, a total of 195 yeast isolates were sampled from larvae and adult beetles (female and male) of P. koryoensis in Cheonan, Goyang, and Paju; 8 species were identified by based on their morphological, biochemical and molecular analyses. Meyerozyma guilliermondii and Candida kashinagacola were found to be the two dominant species. Among the 8 species, Candida homilentoma was a newly recorded yeast species in Korea, and thus, its mycological characteristics were described. The P. koryoensis symbiont R. quercusmongolicae did not show extracelluar CM-cellulase, xylanase and avicelase activity that are responsible for degradation of wood structure; however, C. kashinagacola and M. guilliermondii did show the three extracellular enzymatic activities. Extracelluar CM-cellulase activity was also found in Ambrosiozyma sp., C. homilentoma, C. kashinagacola, and Candida sp. Extracelluar pectinase activity was detected in Ambrosiozyma sp., C. homilentoma, Candida sp., and M. guilliermondii. All the 8 yeast species displayed compatible relationships with R. quercus-mongolicae when they were co-cultivated on yeast extract-malt extract plates. Overall, our results demonstrated that P. koryoensis carries the yeast species as a symbiotic fungal associate. This is first report of yeast diversity associated with P. koryoensis.

New Species of Termitomyces (Lyophyllaceae, Basidiomycota) from Sabah (Northern Borneo), Malaysia

  • Seelan, Jaya Seelan Sathiya;Yee, Chong Shu;Fui, Foo She;Dawood, Mahadimenakbar;Tan, Yee Shin;Kim, Min-Ji;Park, Myung Soo;Lim, Young Woon
    • Mycobiology
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    • v.48 no.2
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    • pp.95-103
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    • 2020
  • The genus Termitomyces (Lyophyllaceae, Basidiomycota) is often associated with fungus-feeding termites (Macrotermitinae) due to their strong symbiotic relationships. The genus is widely found exclusively in certain regions of Africa and Asia. They are recognized as edible mushroom within Southeast Asia as well. But it is often misidentified based on morphology by the local communities especially in Malaysia for Chlorophyllum molybdites which is a highly poisonous mushroom. Thus, it is necessary to study the genus for Malaysia with the synergy of using both morphological and molecular identification. In this study, we aim to describe another new species as an addition to the genus Termitomyces found within Sabah, Malaysia. We generated two new sequences (nrLSU and mtSSU) for the new species and a total of 28 nrLSU and mtSSU sequences were retrieved from GenBank for the phylogenetic analysis using maximum likelihood and Bayesian inferences. We identified that the new collection from Sabah province is a new species and named as Termitomyces gilvus based on the termites found in the mound. A phylogeny tree made from the concatenated genes of LSU and mtSSU suggests that T. gilvus is closely related to T. bulborhizus from China. According to our results, the combination of molecular and morphology proved to be a robust approach to re-evaluate the taxonomic status of Termitomyces species in Malaysia. Additional surveys are needed to verify the species diversity and clarify their geographic distribution.

The Effect of Franchisors' Gapjil on Economic Satisfaction, Social Satisfaction, and Recontract Intention

  • HUR, Soon-Beom;LEE, Yong-Ki
    • The Korean Journal of Franchise Management
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    • v.12 no.2
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    • pp.35-49
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    • 2021
  • Purpose: The major objective of this study is to develop a model for the impact of franchisors' Gapjil (verbal·nonverbal Gapjil, abusing bargaining position, refusing transaction, false or exaggerated information, restrictive practices, unfair damage compensation) on franchisee's recontract intention. We also examine the mediating role of economic satisfaction and social satisfaction in the relationship between franchisors' Gapjil and franchisee's contract intention. Research design, data, and methodology: Data were collected from franchisee owners located nationwide in Korea. Out of 256 questionaires distributed, a total of 256 questionnaires were returned. After excluding 10 invalid respondent questionnaires, we coded and analyzed 246 valid questionnaires (effective response rate of 96.09%) using frequency, confirmatory factor analysis, correlations analysis, and structural equation modeling with SPSS 22.O and SmartPLS 3.0. Results: The findings of this study are summarized as follows: First, among the Gapjil of the franchisors, restrictive practices and unfair damage compensation had negative effects on economic and social satisfaction, but verbal and nonverbal Gapjil for economic and social satisfaction was not significant. Second, abusing bargaining positions and false or exaggerated information had negative effects on social satisfaction, but for economic satisfaction, found to be insignificant. Third, economic and social satisfaction had positive effects on the franchisee's recontract intention to the franchisor. Conclusion: The following implications of this study are as follows. First, the construct of Gapjil that occurs between the franchisors and the franchisees was first presented, and the franchisors' Gapjil is divided into interpersonal Gapjil and structural Gapjil. Second, the Gapjil of the franchisors can be an important predictor variable in maintaining and developing a long-term relationship between the franchisors and the franchisees. Third, solving conflict due to the Gapjil problem between franchisors and franchisees can be an important factor for franchisors and franchisees to co-survive and thrive in Korean franchise system. Fourth, this study suggest that managing the Gapjil of the franchisors was a important antecedent factor in maintaining long-term relationship between the franchisors and the franchisees. Therefore, this study will help franchisors formulate effective symbiotic marketing strategies to satisfy relationships with franchisees and consequently enhance long-term orientation.

The Mediation Effects of Depressive Symptoms on the Association between Social Activity Participation and Marital Satisfaction among Couples in Later Life: Using APIMeM Modeling (노년기 부부의 사회활동 참여수준이 부부관계 만족도에 미치는 영향에 대한 우울감의 매개효과: APIMeM 모형을 활용하여)

  • Kim, Yulri;Joo, Susanna;Lee, Yeseul;Kim, Hyoun K.
    • Human Ecology Research
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    • v.60 no.3
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    • pp.471-481
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    • 2022
  • This study aimed at examining the mediation effects of depressive symptoms on the association between social activity participation and marital satisfaction among couples in later life. The study included 1,196 married couples aged 65 or above who participated in the 7th Korean Longitudinal Study of Aging in 2018. The study variables were husbands' and wives' social activity participation, marital satisfaction, and depressive symptoms. Covariates were individual age, education level, subjective health, couples' household income, and number of children. The Actor-Partner Interdependence Mediation Model (APIMeM) and bootstrapping techniques were used to test the significance of the mediating impacts of depressive symptoms based on the dyadic data structure. The results showed that for both husbands and wives, active participation in social activities had significant effects on increasing marital satisfaction through lowering depressive symptoms. However, only the participation of husbands in social activities was positively associated with their own marital satisfaction by reducing their own and their partner's depressive symptoms. These findings suggest that the active social participation of individuals salient for promoting the quality of marital relationships in later life, particularly for preventing their own and their spouse's depressive symptoms.

Phylogenetic Analysis of 680 Prokaryotes by Gene Content (유전자 보유 계통수를 이용한 원핵생물 680종의 분석)

  • Lee, Dong-Geun;Lee, Sang-Hyeon
    • Journal of Life Science
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    • v.26 no.6
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    • pp.711-720
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    • 2016
  • To determine the degree of common genes and the phylogenetic relationships among genome-sequenced 680 prokaryotes, the similarities among 4,631 clusters of orthologous groups of protein (COGs)’ presence/ absence and gene content trees were analyzed. The number of COGs was in the range of 103–2,199 (mean 1377.1) among 680 prokaryotes. Candidatus Nasuia deltocephalinicola str. NAS-ALF, an obligate symbiont with insects, showed the minimum COG, while Pseudomonas aeruginosa PAO1, an opportunistic pathogen, represented the maximum COG. The similarities between two prokaryotes were 49.30–99.78 % (mean 72.65%). Methanocaldococcus jannaschii DSM 2661 (hyperthermophilic and autotrophic, Euryarchaeota phylum) and Mesorhizobium loti MAFF303099 (mesophilic and symbiotic, alpha-Proteobacteria class) had the minimum amount of similarities. As gene content may represent the potential for an organism to adapt to each habitat, this may represent the history of prokaryotic evolution or the range of prokaryotic habitats at present on earth. COG content trees represented the following. First, two members of Chloroflexi phylum (Dehalogenimonas lykanthroporepellens BL-DC-9 and Dehalococcoides mccartyi 195) showed a greater relationship with Archaea than other Eubacteria. Second, members of the same phylum or class in the 16S rRNA gene were separated in the COG content tree. Finally, delta- and epsilon-Proteobacteria were in different lineages with other Proteobacteria classes in neighbor-joining (NJ) and maximum likelihood (ML) trees. The results of this study would be valuable to identifying the origins of organisms, functional relationships, and useful genes.

The Sangsaeng Ecological Theory of Daesoon Jinrihoe: Focusing on the Meaning of Sangsaeng (대순진리회의 상생생태론 연구 - 상생의 의미를 중심으로 -)

  • Kim Gui-man
    • Journal of the Daesoon Academy of Sciences
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    • v.48
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    • pp.375-406
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    • 2024
  • This study aims to define the meaning of 'Sangsaeng (mutual beneficence)' within the context of 'Sangsaeng ecological theory,' a form of discourse of that has emerged from Daesoon Jinrihoe's perspective on ecology. Sangsaeng ecological theory applies the concept of interdependence to ecology in order to explain how Sangsaeng, which is commonly used as an ethical system for humans, can be applied to the realm of ecology such that it extends its scope of application to include non-human beings. Interdependence, when applied to ecology, is formed via relationships between individuals. Such relationships can be positive, negative, or neutral, and the type of interdependence that emerges can be competitive, predatory, parasitc, and symbiotic. Even if the relationship between individuals ends negatively, it can still exert a positive effect on the ecosystem. Consequently, all of these produce a type of 'dependence'. However, relationships that end negatively can generate grievances, and from the perspective of Sangsaeng ethics, this type of interdependence is to be avoided. Therefore, by way of contrast, ecological Sangsaeng may include both relationships of positive interdependence and relationships of predation, parasitism, and competition in so far as there no grievances. Ecological theory requires a perspective that enables an understand of the relationship between nature and humans in an integrated way that does not separate them. One view of universe, known as Cheonji-saengin-yongin (Heaven and Earth give produce humans make use of them) provides insights into the relationship between the universe and humans and nature and humans from an interdependent perspective. Heaven and Earth take humans as the basis of their existence, and only after humans discover the law of nature and the sacredness behind it can a deep interdependence between Heaven and Earth and humans and nature and humans be established. However, as modern humans emerge, the interdependence between Heaven and Earth and humans collapses as they destroy nature and lower the authority of Shindo (divine order). Haewon Sangsaeng (the resolution of grievances for mutual beneficence) and Boeun Sangsaeng (the reciprocation of favors for mutual beneficence) is the solution to reestablish the interdependence that has been disconnected between Heaven and Earth and humans and nature and humans. The practice of Haewon Sangsaeng through Gongbu rituals is the way to restore interdependence between nature and humans. The process of humans achieving Dotong (mastery of the Dao) through religious practices is the practice of Boeun Sangsaeng, and humans will be reborn into Injon (Human Nobility or 'divine humans') with ecological nature and enjoy an eternal interdependent relationship with nature. In summary, Sangsaeng in the context of Sangsaeng ecological theory is the idea and practice of allowing nature and humans to restore their interdependence and live on eternally.