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Effect of Water Activity and Temperature on Growth, Germination, Sporulation, and Utilization of Carbon Source of Penicillium oxalicum (PENOX) as a Biocontrol Agent(BCA) for control of Clover(Trifolium repens L.) (토끼풀(Trifolium repens L.) 방제용 생물제제 Penicillium oxalicum (PENOX)의 발아, 생장, 포자생성 및 탄소원이용에 미치는 수분활성 및 온도의 영향)

  • Lee, Hyang-Burm;Kim, Chang-Jin
    • The Korean Journal of Pesticide Science
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    • v.4 no.3
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    • pp.68-74
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    • 2000
  • Penicillium oxalicum (PENOX) has shown the potential as a biocontrol agent(5CA) for control of a weed, clover(Trifolium repens L.) in grass plots. The bioherbicidal activity may be due to germinative and growth capacities and substrate availability of the agent over a range of environmental factors. The influences of different water activities($0.94{\sim}0.995\;a_w$) and temperatures($18{\sim}30^{\circ}C$) on mycelial growth, conidial germination, sporulation oil 2% MEA(malt extract agar) adjusted to different water activities with glycerol, and carbon source utilization using BIOLOG GN MicroPlate were determined in vitro. Decreases in $a_w$ on MEA caused a reduction in mycelial growth and conidial germination depending on temperature. The mycelial growth of PENOX was greatest at $30^{\circ}C/0.995\;a_w$. At some lowered water activity($0.97\;a_w$), the growth was similar between 25 and $30^{\circ}C$, and considerably decreased at lowered temperature($20^{\circ}C$). The germination rate was also greatest at $30^{\circ}C/0.995\;a_w$. Lag phase times for PENOX at $18^{\circ}C$ on MEA were >6hrs at tile whole $a_w$ level tested, and at 18 and $25^{\circ}C$ they were >18hrs and >12hrs at $0.94\;a_w$, respectively. However, its sporulation was some better at $0.97\;a_w$ than $0.995\;a_w$ or $0.94\;a_w$, and better at $20^{\circ}C$ than $30^{\circ}C$. In contrast, the number of carbon sources(niche size) utilized by PENOX varied with $a_w$ and temperature. Under some water stress condition($0.95\;a_w$), the agent utilized smaller number of carbon sources than $0.995\;a_w$ depending on temperature. The niche size at 0.995 and $0.95\;a_w$ were highest at $25^{\circ}C$, and showed 86 and 65, respectively. At $30^{\circ}C$, the niche size at 0.995 and $0.95\;a_w$ showed 84 and 50, respectively. There was no carbon source utilized by PENOX at $0.90\;a_w$ regardless of temperature. These information of tile fungal ecophysiology will be useful for the effective development of BCA.

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Origin and Reservoir Types of Abiotic Native Hydrogen in Continental Lithosphere (대륙 암석권에서 무기 자연 수소의 성인과 부존 형태)

  • Kim, Hyeong Soo
    • Korean Journal of Mineralogy and Petrology
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    • v.35 no.3
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    • pp.313-331
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    • 2022
  • Natural or native abiotic molecular hydrogen (H2) is a major component in natural gas, however yet its importance in the global energy sector's usage as clean and renewable energy is underestimated. Here we review the occurrence and geological settings of native hydrogen to demonstrate the much widesprease H2 occurrence in nature by comparison with previous estimations. Three main types of source rocks have been identified: (1) ultramafic rocks; (2) cratons comprising iron (Fe2+)-rich rocks; and (3) uranium-rich rocks. The rocks are closely associated with Precambrian crystalline basement and serpentinized ultramafic rocks from ophiolite and peridotite either at mid-ocean ridges or within continental margin(Zgonnik, 2020). Inorganic geological processes producing H2 in the source rocks include (a) the reduction of water during the oxidation of Fe2+ in minerals (e.g., olivine), (b) water splitting due to radioactive decay, (c) degassing of magma at low pressure, and (d) the reaction of water with surface radicals during mechanical breaking (e.g., fault) of silicate rocks. Native hydrogen are found as a free gas (51%), fluid inclusions in various rock types (29%), and dissolved gas in underground water (20%) (Zgonnik, 2020). Although research on H2 has not yet been carried out in Korea, the potential H2 reservoirs in the Gyeongsang Basin are highly probable based on geological and geochemical characteristics including occurrence of ultramafic rocks, inter-bedded basaltic layers and iron-copper deposits within thick sedimentary basin and igneous activities at an active continental margin during the Permian-Paleogene. The native hydrogen is expected to be clean and renewable energy source in the near future. Therefore it is clear that the origin and exploration of the native hydrogen, not yet been revealed by an integrated studies of rock-fluid interaction studies, are a field of special interest, regardless of the presence of economic native hydrogen reservoirs in Korea.

EVALUATION OF OSTEOGENIC ACTIVITY AND MINERALIZATION OF CULTURED HUMAN PERIOSTEAL-DERIVED CELLS (배양된 인간 골막기원세포의 조골활성 및 골기질 형성의 평가)

  • Park, Bong-Wook;Byun, June-Ho;Lee, Sung-Gyoon;Hah, Young-Sool;Kim, Deok-Ryong;Cho, Yeong-Cheol;Sung, Iel-Yong;Kim, Jong-Ryoul
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.28 no.6
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    • pp.511-519
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    • 2006
  • Autogenous bone grafts have been considered the gold standard for maxillofacial bony defects. However, this procedure could entail a complicated surgical procedure as well as potential donor site morbidity. Possibly the best solution for bone-defect regeneration is a tissue engineering approach, i.e. the use of a combination of a suitable scaffold with osteogenic cells. A major source of osteogenic cells is the bone marrow. Bone marrow-derived mesenchymal stem cells are multipotent and have the ability to differentiate into osteoblastic, chondrocytic, and adipocytic lineage cells. However, the isolation of cells from bone marrow has someproblems when used in clinical setting. Bone marrow aspiration is sometimes potentially more invasive and painful procedure and carries of a risk of morbidity and infection. A minimally invasive, easily accessible alternative would be cells derived from periosteum. The periosteum also contains multipotent cells that have the potential to differentiate into osteoblasts and chondrocytes. In the present study, we evaluated the osteogenic activity and mineralization of cultured human periosteal-derived cells. Periosteal explants were harvested from mandibule during surgical extraction of lower impacted third molar. The periosteal cells were cultured in the osteogenic inductive medium consisting of DMEM supplemented with 10% fetal calf serum, 50g/ml L-ascorbic acid 2-phosphate, 10 nmol dexamethasone and 10 mM -glycerophosphate for 42 days. Periosteal-derived cells showed positive alkaline phosphatase (ALP) staining during 42 days of culture period. The formation of ALP stain showed its maximal manifestation at day 14 of culture period, then decreased in intensity during the culture period. ALP mRNA expression increased up to day 14 with a decrease thereafter. Osteocalcin mRNA expression appeared at day 7 in culture, after that its expression continuously increased in a time-dependent manner up to the entire duration of culture. Von Kossa-positive mineralization nodules were first present at day 14 in culture followed by an increased number of positive nodules during the entire duration of the culture period. In conclusion, our study showed that cultured human periosteal-derived cells differentiated into active osteoblastic cells that were involved in synthesis of bone matrix and the subsequent mineralization of the matrix. As the periosteal-derived cells, easily harvested from intraoral procedure such as surgical extraction of impacted third molar, has the excellent potential of osteogenic capacity, tissue-engineered bone using periosteal-derived cells could be the best choice in reconstruction of maxillofacial bony defects.

The Impact of Perceived Risks Upon Consumer Trust and Purchase Intentions (인지된 위험의 유형이 소비자 신뢰 및 온라인 구매의도에 미치는 영향)

  • Hong, Il-Yoo B.;Kim, Woo-Sung;Lim, Byung-Ha
    • Asia pacific journal of information systems
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    • v.21 no.4
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    • pp.1-25
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    • 2011
  • Internet-based commerce has undergone an explosive growth over the past decade as consumers today find it more economical as well as more convenient to shop online. Nevertheless, the shift in the common mode of shopping from offline to online commerce has caused consumers to have worries over such issues as private information leakage, online fraud, discrepancy in product quality and grade, unsuccessful delivery, and so forth, Numerous studies have been undertaken to examine the role of perceived risk as a chief barrier to online purchases and to understand the theoretical relationships among perceived risk, trust and purchase intentions, However, most studies focus on empirically investigating the effects of trust on perceived risk, with little attention devoted to the effects of perceived risk on trust, While the influence trust has on perceived risk is worth studying, the influence in the opposite direction is equally important, enabling insights into the potential of perceived risk as a prohibitor of trust, According to Pavlou (2003), the primary source of the perceived risk is either the technological uncertainty of the Internet environment or the behavioral uncertainty of the transaction partner. Due to such types of uncertainty, an increase in the worries over the perceived risk may negatively affect trust, For example, if a consumer who sends sensitive transaction data over Internet is concerned that his or her private information may leak out because of the lack of security, trust may decrease (Olivero and Lunt, 2004), By the same token, if the consumer feels that the online merchant has the potential to profit by behaving in an opportunistic manner taking advantage of the remote, impersonal nature of online commerce, then it is unlikely that the merchant will be trusted, That is, the more the probable danger is likely to occur, the less trust and the greater need to control the transaction (Olivero and Lunt, 2004), In summary, a review of the related studies indicates that while some researchers looked at the influence of overall perceived risk on trust level, not much attention has been given to the effects of different types of perceived risk, In this context the present research aims at addressing the need to study how trust is affected by different types of perceived risk, We classified perceived risk into six different types based on the literature, and empirically analyzed the impact of each type of perceived risk upon consumer trust in an online merchant and further its impact upon purchase intentions. To meet our research objectives, we developed a conceptual model depicting the nomological structure of the relationships among our research variables, and also formulated a total of seven hypotheses. The model and hypotheses were tested using an empirical analysis based on a questionnaire survey of 206 college students. The reliability was evaluated via Cronbach's alphas, the minimum of which was found to be 0.73, and therefore the questionnaire items are all deemed reliable. In addition, the results of confirmatory factor analysis (CFA) designed to check the validity of the measurement model indicate that the convergent, discriminate, and nomological validities of the model are all acceptable. The structural equation modeling analysis to test the hypotheses yielded the following results. Of the first six hypotheses (H1-1 through H1-6) designed to examine the relationships between each risk type and trust, three hypotheses including H1-1 (performance risk ${\rightarrow}$ trust), H1-2 (psychological risk ${\rightarrow}$ trust) and H1-5 (online payment risk ${\rightarrow}$ trust) were supported with path coefficients of -0.30, -0.27 and -0.16 respectively. Finally, H2 (trust ${\rightarrow}$ purchase intentions) was supported with relatively high path coefficients of 0.73. Results of the empirical study offer the following findings and implications. First. it was found that it was performance risk, psychological risk and online payment risk that have a statistically significant influence upon consumer trust in an online merchant. It implies that a consumer may find an online merchant untrustworthy if either the product quality or the product grade does not match his or her expectations. For that reason, online merchants including digital storefronts and e-marketplaces are suggested to pursue a strategy focusing on identifying the target customers and offering products that they feel best meet performance and psychological needs of those customers. Thus, they should do their best to make it widely known that their products are of as good quality and grade as those purchased from offline department stores. In addition, it may be inferred that today's online consumers remain concerned about the security of the online commerce environment due to the repeated occurrences of hacking or private information leakage. Online merchants should take steps to remove potential vulnerabilities and provide online notices to emphasize that their website is secure. Second, consumer's overall trust was found to have a statistically significant influence on purchase intentions. This finding, which is consistent with the results of numerous prior studies, suggests that increased sales will become a reality only with enhanced consumer trust.

Physiological Activity of Methanol Extracts from Sambucus sieboldiana var. miquelii (Nakai) Hara (지렁쿠나무 메탄올 추출물의 생리활성 연구)

  • Oh, Yu Jin;Cho, Hae Jin;Woo, Hyun Sim;Byeon, Jun-Gi;Kim, Yeong-Su;Kim, Dae Wook
    • Journal of Life Science
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    • v.30 no.11
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    • pp.965-972
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    • 2020
  • Sambucus sieboldiana var. miquelii (Nakai) Hara is distributed in Korea, China, and Japan, and has been used as an anti-rheumatic in folk medicine in oriental countries. The present study aims to investigate the potential use of this species in health functional foods, cosmetics, and food preservatives. Methanol extracts of leaves and branches from this plant were prepared to quantitatively analyze the total phenol and flavonoid contents, and to investigate the antioxidative and enzyme inhibitory activities, and the inhibition of nitric oxide (NO) production activity. The results showed that the total polyphenol and flavonoid contents of the crude extract were 1.52±0.1 mg/g and 1.73±0.1 mg/g, respectively. S. sieboldiana polyphenols exhibited potent scavenging activity shown by 2, 2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation assay. The crude extract also exhibited significant α-glucosidase and tyrosinase inhibitory activity with IC50 values of 183.5 ㎍/ml and 323.9 ㎍/ ml, respectively. Additionally, the crude extract exhibited strong anti-inflammatory activity determined through the nitric oxide inhibition assay in a dose-dependent manner with an IC50 value of 36.7 ㎍/ml and no cytotoxic effect on the macrophages. Therefore, we demonstrated that the leaves and branches of S. sieboldiana extract possess antioxidant, anti-diabetic, depigmentation potential, and NO production inhibitory activities. According to recent research, S. sieboldiana has great potential as a source of the bioactive compound which could be used as food, cosmetics, and pharmaceutical agents.

Recent Advancement in the Stem Cell Biology (Stem Cell Biology, 최근의 진보)

  • Harn, Chang-Yawl
    • Journal of Plant Biotechnology
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    • v.33 no.3
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    • pp.195-207
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    • 2006
  • Stem cells are the primordial, initial cells which usually divide asymmetrically giving rise to on the one hand self-renewals and on the other hand progenitor cells with potential for differentiation. Zygote (fertilized egg), with totipotency, deserves the top-ranking stem cell - he totipotent stem cell (TSC). Both the ICM (inner cell mass) taken from the 6 days-old human blastocyst and ESC (embryonic stem cell) derived from the in vitro cultured ICM have slightly less potency for differentiation than the zygote, and are termed pluripotent stem cells. Stem cells in the tissues and organs of fetus, infant, and adult have highly reduced potency and committed to produce only progenitor cells for particular tissues. These tissue-specific stem cells are called multipotent stem cells. These tissue-specific/committed multipotent stem cells, when placed in altered environment other than their original niche, can yield cells characteristic of the altered environment. These findings are certainly of potential interest from the clinical, therapeutic perspective. The controversial terminology 'somatic stem cell plasticity' coined by the stem cell community seems to have been proved true. Followings are some of the recent knowledges related to the stem cell. Just as the tissues of our body have their own multipotent stem cells, cancerous tumor has undifferentiated cells known as cancer stem cell (CSC). Each time CSC cleaves, it makes two daughter cells with different fate. One is endowed with immortality, the remarkable ability to divide indefinitely, while the other progeny cell divides occasionally but lives forever. In the cancer tumor, CSC is minority being as few as 3-5% of the tumor mass but it is the culprit behind the tumor-malignancy, metastasis, and recurrence of cancer. CSC is like a master print. As long as the original exists, copies can be made and the disease can persist. If the CSC is destroyed, cancer tumor can't grow. In the decades-long cancer therapy, efforts were focused on the reducing of the bulk of cancerous growth. How cancer therapy is changing to destroy the origin of tumor, the CSC. The next generation of treatments should be to recognize and target the root cause of cancerous growth, the CSC, rather than the reducing of the bulk of tumor, Now the strategy is to find a way to identify and isolate the stem cells. The surfaces of normal as well as the cancer stem cells are studded with proteins. In leukaemia stem cell, for example, protein CD 34 is identified. In the new treatment of cancer disease it is needed to look for protein unique to the CSC. Blocking the stem cell's source of nutrients might be another effective strategy. The mystery of sternness of stem cells has begun to be deciphered. ESC can replicate indefinitely and yet retains the potential to turn into any kind of differentiated cells. Polycomb group protein such as Suz 12 repress most of the regulatory genes which, activated, are turned to be developmental genes. These protein molecules keep the ESC in an undifferentiated state. Many of the regulator genes silenced by polycomb proteins are also occupied by such ESC transcription factors as Oct 4, Sox 2, and Nanog. Both polycomb and transcription factor proteins seem to cooperate to keep the ESC in an undifferentiated state, pluripotent, and self-renewable. A normal prion protein (PrP) is found throughout the body from blood to the brain. Prion diseases such as mad cow disease (bovine spongiform encephalopathy) are caused when a normal prion protein misfolds to give rise to PrP$^{SC}$ and assault brain tissue. Why has human body kept such a deadly and enigmatic protein? Although our body has preserved the prion protein, prion diseases are of rare occurrence. Deadly prion diseases have been intensively studied, but normal prion problems are not. Very few facts on the benefit of prion proteins have been known so far. It was found that PrP was hugely expressed on the stem cell surface of bone marrow and on the cells of neural progenitor, PrP seems to have some function in cell maturation and facilitate the division of stem cells and their self-renewal. PrP also might help guide the decision of neural progenitor cell to become a neuron.

Estimation of Biomass Resource Conversion Factor and Potential Production in Agricultural Sector (농업부문 바이오매스 자원 환산계수 및 잠재발생량 산정)

  • Park, Woo-Kyun;Park, Noh-Back;Shin, Joung-Du;Hong, Seung-Gil;Kwon, Soon-Ik
    • Korean Journal of Environmental Agriculture
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    • v.30 no.3
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    • pp.252-260
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    • 2011
  • BACKGROUND: Currently, national biomass inventory are being established for efficient management of the potential energy sources. Among the various types of biomass, agricultural wastes are considered to take the biggest portion of the total annual biomass generated in Korea, implying its importance. However, the currently estimated amount is not reliable because the old reference data are still used to estimate total annual amount of agricultural wastes. METHODS AND RESULTS: Therefore, to provide reliable estimation data, a correct conversion factor obtained by taking into account the current situation is required. For this, the current study was conducted to provide the conversion factors for each representative 8 crop through a field cultivation study. Also conversion factors for 18 crops were calculated using the average amount of each crop produced during 2004 and 2008, subsequently; total amount of agricultural wastes generated in 2009 was estimated using these conversion factors. The total biomass of rice straw and rice husk generated in 2009 were 6.5 and 1.1 million tons, respectively, which consist 75% of the total agricultural based wastes, while the total biomass of pepper shoots and apple pruning twigs were 1.0 and 0.6 million tons, respectively. Despite the high amount of rice-based biomass, their applicability for bio-energy production is low due to conventional utilization of these materials for animal feeds and beds for animal husbandry. In addition to exact estimation of the total biomass, temporal variations in both generated amount and the type of agricultural biomass materials are also important for efficient utilization; fruit pruning twigs (January to March); barley-, been-, and mustard-related waste materials (April to June); rice-related waste (September to October). CONCLUSION(s): Such information provided in this study can be used to establish a master plan for efficient utilization of the agricultural wastes on purpose of bio-energy production.

Assessment of The Biomass Potential Recovered from Oil Palm Plantation and Crude Palm Oil Production in Indonesia (인도네시아 오일 팜 바이오매스 잠재량 평가)

  • Ahn, Byoung-Jun;Han, Gyu-Seoung;Choi, Don-Ha;Cho, Sung-Taig;Lee, Soo-Min
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.3
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    • pp.231-243
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    • 2014
  • In this study, the potential of biomass, which is generated from oil palm cultivation and crude palm oil (CPO) production of Indonesia was assessed in the aspect of energy content. The types of oil palm biomass were classified on the basis of the cultivation stage and the CPO production stage. In the cultivation stage, biomass is considered to be produced from its' root, trunk and frond. Other possible biomass resources such as empty fruit bunch (EFB), palm kernel shell (PKS) and fiber were included in the CPO production stage. As results, total biomass from damaged plantation area of Indonesia was estimated to be annually from 3 million to 16 million tons in 2011. From CPO mills, approximately 49 million tons/yr of biomass residues were estimated to be annually occurred. Their total energy content from each biomass source in cultivation stage was analyzed to be from 593,000 to 3,197,000 TOEs in terms of gross calorific value. In the case of CPO mills, around 22.7 million TOEs was estimated to be potential energy producible by biomass based on gross calorific value of dry basis. If moisture content considered, net calorific value was analyzed to be decreased to 16.3 million TOEs. Based on the results, the total energy contents of all oil palm biomass were estimated to be up to 25,919,000 TOE in terms of gross calorific value. CPO : Crude Palm Oil, EFB : Empty Fruit Bunch, FFB: Fresh Fruit Bunch, PKS : Palm Kernel Shell, OPF : Oil Palm Frond, PKOC : Palm Kernel Oil Cake, ISPO : Indonesia Sustainable Palm Oil Commission, TOE : Tone of Oil Equivalent.

The Determination of Trust in Franchisor-Franchisee Relationships in China (중국 프랜차이즈 시스템에서의 본부와 가맹점간 신뢰의 영향요인)

  • Shin, Geon-Cheol;Ma, Yaokun
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.2
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    • pp.65-88
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    • 2008
  • Since the implementation of economic reforms in 1978, the Chinese economy grows rapidly at an average annul growth rate of 9% over the post two decades. Franchising has been widely recognized as an important source of entrepreneurial activity. Trust is important in that it facilitates relational exchanges by permits partners to transcend short-run inequities or risks to concentrate on long-term profits or gains. In the relationship between the franchisors and franchisees, trust has been described as an important source of competitive advantage. However, little research has been done on the factors affecting trust in Chinese franchisor-franchisee relationships. The purpose of this study is to investigate what factors affect the trust in the franchise system in China, and to provide guidelines and insights to franchisors which enter Chinese market. In this study, according to Morgan and Hunt (1994), trust is defined as the extending when one party has confidence in an exchange partner's reliability and integrity. We offered a conceptual model of the empirical study. The model shows that the factors affecting the trust include franchisor's supports, communication, satisfaction with previous outcome and conflict. We also suggested the franchisor's supports and communication like to enhance the franchisee's satisfaction with previous outcome, and the franchisor's supports, communication and he franchisee's satisfaction with previous outcome tend to decrease conflict. Before the formal study, a pretest involving exploratory interviews with owners from three franchisees was conducted to make sure the questionnaire was relevant and clear to the respondents. The data were collected using trained interviewers to carry out personal interviews with the aid of an unidentified, muti-page, structured questionnaire. The respondents comprised of owners, managers, and owner managers of franchisee-owned food service franchises located in Beijing, China. Even though a total of 256 potential franchises were initially contacted, the finally usable sample consisted of 125 respondents. As expected, the sampling method was successful in soliciting respondents with waried personal and firm characteristics. Self-administrated questionnaires were used for all measures. And established scales were used to measure the latent constructs in this study. The measures tapped the franchisees' perceptions of the relationship with the referent franchisor. Five-point Likert-type scales ranging from "strongly disagree" (=1) to "strongly agree" (=7) were used throughout the constructs (trust, eight items; support, five items; communication, four items; satisfaction, six items; conflict, three items). The reliability measurements traditionally employed, such as the Cronbach's alpha, were used. All the reliabilities were greater than.80. The proposed measurement model was estimated using SPSS 12.0 and AMOS 5.0 analysis package. We conducted A series of exploratory factor analyses and confirmatory factor analyses to assess the convergent validity, discriminant validity, and reliability. The results indicate reasonable overall fits between the model and the observed data. The overall fit of measurement model were $X^2$= 159.699, p=0.004, d.f. = 116, GFI =.879, NFI =.898, CFI =.969, IFI =.970, TLI =.959, RMR =.058. The results demonstrated that the data reasonably fitted the model. We also examined construct reliability and reliability and average variance extracted (AVE). The construct reliability of each construct was greater than.80 and the AVE of each construct was greater than.50. According to the analysis of Structure Equation Modeling (SEM), the results of path model indicated an adequate fit of the model: $X^2$= 142.126, p = 0.044, d.f. = 115, GFI =.892, NFI =.909, CFI =.981, IFI =.981, TLI =.974, RMR =.057. As hypothesized, the results showed that it is strategically important to establish trust in a franchise system, and the franchisor's supports, communication and satisfaction with previous outcome tend to reinforce franchisee's trust. The results also showed trust seems to decrease as the experience of conflict episodes increases. And we also noticed that franchisor's supports and communication tend to enhance the franchisee's satisfaction with previous outcome, and communication tend to decrease conflict. If the trust between the franchisor and franchisee can be established in a franchise system, franchising offers many benefits and reduces many costs. To manage a mutual trust of relationship with their franchisees, franchisor's should provide support effectively to their franchisees. Effective assistant services have direct effect on franchisees' satisfaction with previous outcome and trust in franchisor. Especially, franchise sales process, orientation, and training in the start-up period are key elements for success of the franchise system. Franchisor's support is an accumulated separate satisfaction evaluation with different kind of service provided by the franchisor. And providing support definitely can improve the trustworthy image of the franchisor. In the franchise system, conflicts of interests and exertions of different power sources are very common. The experience of conflict episodes seems to negatively relate to trust. Therefore, it is important to reduce the negative side of the relationship conflicts. Communication actually plays a broader role in reducing conflict and establish mutual trust in franchisor-franchisee relationship. And effective communication between franchisors and franchisees can improve franchisees' satisfaction toward the franchise system. As the diversification of Chinese markets, both franchisors and franchisees must keep the relevant, timely, and reliable communication. And it is very important to improve the quality of communication. Satisfaction with precious outcomes seems to positively relate to trust. Franchisors and franchisees that are highly satisfied with the previous outcomes that flow from their relationship will perceive their partner as advancing their goal achievement. Therefore, it is necessary for both franchisor and their franchisees to make the welfare of partner with effort. Little literature has focused on what factors affect the trust between franchisors and their franchisees in China. This study developed the hypotheses regarding the factors affecting trust in the transaction relationship. The results of data analysis supported the hypotheses strongly. There are certain limitations in this study. First, we may point out that some other factors missed in this study could be significantly important. Second, the context of this study, food service industry, limits its potential generalizability for all franchise systems. More studies in different categories of franchise system are needed to broaden its generalizability. Third, the model was tested empirically in a sample in Beijing, more empirical tests of the proposed model in other Chinese areas are needed. Finally, the analysis in this study was solely based on the perception of franchisees and the opinions of franchisors were not included.

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Purification, Characterization, and Cloning of Fibrinolytic Metalloprotease from Pleurotus ostreatus Mycelia

  • Shen, Ming-Hua;Kim, Jae-Sung;Sapkota, Kumar;Park, Se-Eun;Choi, Bong-Suk;Kim, Seung;Lee, Hyun-Hwa;Kim, Chun-Sung;Chun, Hong-Sung;Ryoo, Cheon-In;Kim, Sung-Jun
    • Journal of Microbiology and Biotechnology
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    • v.17 no.8
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    • pp.1271-1283
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    • 2007
  • A fibrinolytic protease (PoFE) was purified from the cultured mycelia of the edible oyster mushroom Pleurotus ostreatus, using a combination of various chromatographies. The purification protocol resulted in an 876-fold purification of the enzyme, with a final yield of 6.5%. The apparent molecular mass of the purified enzyme was estimated to be 32 kDa by SDS-PAGE, fibrin-zymography, and size exclusion using FPLC. The optimal reaction pH value and temperature were pH 6.5 and $35^{\circ}C$, respectively. PoFE effectively hydrolyzed fibrinogen, preferentially digesting the $A{\alpha}$-chain and the $B{\beta}$-chain over the ${\gamma}$-chain. Enzyme activity was enhanced by the addition of $Ca^{2+},\;Zn^{2+},\;and\;Mg^{2+}$ ions. Furthermore, PoFE activity was potently inhibited by EDTA, and it was found to exhibit a higher specificity for the chromogenic substrate S-2586 for chymotrypsin, indicating that the enzyme is a chymotrypsin-like metalloprotease. The first 19 amino acid residues of the N-terminal sequence were ALRKGGAAALNIYSVGFTS, which is extremely similar to the metalloprotease purified from the fruiting body of P. ostreatus. In addition, we cloned the PoFE protein, encoding gene, and its nucleotide sequence was determined. The cDNA of cloned PoFE is 867 nucleotides long and consists of an open reading frame encoding 288 amino acid residues. Its cDNA showed a high degree of homology with PoMEP from P. ostreatus fruiting body. The mycelia of P. ostreatus may thus represent a potential source of new therapeutic agents to treat thrombosis.