As ZIF materials have their unique properties such as high surface area, tunable pore structure, thermal and chemical stability, they can be used in gas separation. In this work, we synthesized ZIF-8 seed layer by combining ZnO coating on the support and the conversion synthesis of ZnO layer in H-mIm solution to ZIF-8 layer, followed by the secondary growth synthesis for ZIF-8 membranes. The effect of solvent on conversion seeding had been investigated to control the reaction rate combining the dissolution rate of ZnO and the crystallization rate. The optimum solvent combination (water and methanol) was studied according to the thickness of the ZnO layer used in the conversion seeding. The obtained membranes showed excellent performance for propylene/propane gas separation. The thicker the ZnO layer, the lower the permeability.

ZIFs (Zeolitic imdazolate frameworks)은 높은 화학적⋅열적 안정성, 높은 비표면적과 조절 가능한 기공구조로 최근 분리막 소재로 큰 관심을 받고 있다. 본 연구에서는 두 가지 종류의 다공성 지지체(α-alumina 및 YSZ)를 사용하여 in situ 성장법으로 ZIF-8 분리막을 합성하고, H2/CO2 기체 투과 특성을 조사하였다. 결함 없는 ZIF-8층을 합성하는데 있어, 기공이 작은 YSZ 지지체는 α-alumina 지지체 보다 더 적은 시간이 요구되었다. 합성시간이 3 h인 경우, α-alumina 및 YSZ 지지체 위에 형성된 ZIF-8 분리막은 약 10 정도의 H2/CO2 선택도를 보였다.

As ZIF materials have their unique properties such as high surface area, tunable pore structure, thermal and chemical stability, they can be used in various applications including gas separation and catalysis. For synthesis of ZIF membranes, fixing sub-micron ZIF seed particles on the support is challenging and important. In this work, ZIF-8 seed layer was synthesized by conversion synthesis of ZnO layer on support in H-mIm solution, followed by the secondary growth synthesis of ZIF-8 membranes. The parameters of conversion seeding had been investigated to control the reaction rate combining the dissolution rate of ZnO and the crystallization rate of ZIF-8. This ZIF-8 membranes showed the better coverage of seeding layer and gas separation properties compared with the membranes prepared by traditional dip-coating seeding.

Entomopathogenic fungus is a useful control agent to sucking type insect such as whitefly and aphid. The fungi are influenced by some environmental factors such as relative humidity, temperature and UV and cause slow and fluctuation in pest control efficacy. Especially, UV kills conidia or spores of entomopathogenic fungi and a mycopesticide using fungi has short control period in field. UV intensity changes from season to season. Survival rate of entomopathognic fungi treated may differ from seasons and will show different control efficacy. Therefore, we conducted a study to estimate the persistence of an Isaria javanica isolate, which was already reported as sweet potato whitefly control agent, in potted greenhouse soil planted different crops. The number of survival spore decreased gradually and differ from seasons.

Insect pests have been a serious problem over many years and remain a major threat for food production. Although chemical pesticides are major pest control strategies, use of microorganisms such as entomopathogenic bacteria, fungi, viruses and nematodes have continuously increase last few decades to minimize the use of agrichemicals. According to BBC research, the global biocontrol market was about $2.1 billion in 2011, and this is expected to rise $3 ~ 4 billion by 2017. Over 50 entomopathogens are commercially produced and used augmentatively as microbial pesticides. About 175 biopesticide active ingredients and 700 products have been registered worldwide. Bacillus thuringiensis (Bt), Beauveria bassiana, Metarhizium spp., nuclear polyhedrosis virus and Steinernema spp. are the most popular control agents used in plant protection. Among the microbial control agents Bt products have more than 50% of market share. In Korea, only 13 environmentally-friendly crop protectants were registered for insect pest control in 2015. Market share is very low and has grown slowly. We will discuss how we can expand the market with our techniques.

최근 에너지 효율이 높은 분리 공정기술의 수요가 증가하면서 분리막을 이용한 기체 분리가 큰 관심을 모으고 있다. 현재 분리막에 의한 기체 분리 시장은 고분자막이 독점하고 있으며, 고분자 재료 물성의 한계로 탄화수소와 같은 응축 기체분리보다는 비응축 기체 분리에 제한되고 있다. MOF 재료는 금속 이온과 유기 리간드가 결합하여 형성하는 결정성 나노 기공 구조로, 높은 비표면적과 기공 구조 제어, 기능성 부여가 가능해 분리막 재료로 큰 관심을 끌고 있다. 본 총설에서는 다양한 MOF 분리막의 합성 방법과 MOF 분리막을 통한 기체 분리 응용에 대해 살펴보고자 한다.

The Riptortus-Burkholderia symbiosis is a newly emerging insect-bacterium symbiotic system. This symbiosis system has a good merit as an experimental model system to produce the non-symbiotic (apo) and symbiotic (sym) host insect. In recent reported papers, the symbionts play important biological roles for the host insects. Meanwhile, juvenile hormone (JH) is one of major hormone synthesized corpora allata(CA) to control many physiology of insect. However, the study for cross-talk mechanism between symbionts and host hormones to control important physiological phenomenon of insects is almost none. In this study, we found that Riptortus speed up adult emerging and increase egg laying on presence of symbiont Burkholderia. Also we found that hexamerin proteins, which were controlled the expression by JH, were accumulated in sym-Riptortus hemolymph compare with apo-Riptortus. According as combined results, we hypothesized that the gut symbiont Burkholderia can control JH titer to conclude out beneficial effects such as development and reproduction of R. pedestris. To verify this hypothesis, we examined measurement of JH titer, expression of hexamerins as JH response genes and RNAi for hexamerin protein during whole Riptortus life on presence or absence of symbiont Burkholderia. All results demonstrated that gut symbiont controlled JH titer of Riptortus. Controlled JH amount by symbiont Burkholderia in host midgut regulated hexamerin protein expression for speeding up adult emerging and increasing egg production.

Various insect pests infest crops including vegetables and ornamentals during crop production. Chemical pesticides have generally used until recently to control pests. Many pests are very difficult to control using organic pesticides because of the development of insecticide resistance and their rapid population increase. Entomopathogens are the promising alternative control methods. Entomopathogenic fungi are good candidates to control sucking insects such as aphid, whitefly and mite because the fungi can infect without ingestion. Conidia or blastospores of fungal entomopathogens are sprayed onto target plant and/or insect, adhered on insect surfaces, and penetrated into hemocoel through insect cuticle. Then the fungus utilize insect nutrients and kill the host insect. During this process, fungus was influenced by environmental conditions such as temperature, relative humidity and UV light. These are causing slow mortality and preventing wider application and use of mycopescitide using entomopathogenic fungi. In addition, control efficacy with fungal entomopathogen differed fungal isolate and host insect. Therefore, we need to study selection of high virulence isolate, mass production, formulation and application techniques to develop mycopesticide.

Use of conidia or spores of entomopathogenic fungi are influenced by environmental conditions such as temperature and relative humidity and caused slow and fluctuation of mortality. In addition, although the fungi have the advantage of a restricted host range, this specificity is one of the limiting factors for their use. These factors are preventing wider application and use of these biocontrol agents. To mitigate such problems we selected an Beauveria bassiana Bb08 which kill green peach aphid with its liquid culture filtrate. In this study we conducted bioassay with the fungal culture filtrate and culture fluid to greenhouse pests such as cotton aphid, whitefly and thrips. Culture fluid showed high mortality against green peach aphid, as well as cotton aphid, sweet potato whitefly, and western flower thrips. However, control effect of culture filtrate varied with pests. Culture filtrate showed high mortality to cotton aphid. Mortality of western flower thrips with culture filtrate was slower than culture fluid including spores and sweet potato whitefly was much lower. These results indicated that the culture fluid of Beauveria bassiana Bb08 has potential to simultaneously control various greenhouse pests.

Sweetpotato whitefly (Bemisia tabaci), especially Q biotype, has been recognized one of the most destructive insect pests worldwide because of increased resistance to some insecticide groups requiring alternative strategies for its control. We studied the conidia production of entomopathogenic fungus Isaria javanica Pf04, which had been reported high virulence isolate against Q biotype of B. tabaci, using grain. Brown rice was most suitable for conidia mass production of the isolate of I. javanica. Conidia was produced high at 25 ~ 27.5℃. The isolate produced more spores when conidia suspension directly inoculated onto media than two-phase fermentation. When concentration of inoculum was high spore production was high, but increasing rate of conidia production was highest at low inoculum concentration (1×105 conidia/ml) as 6,700 times increase compared with 20 times increase at high inoculum concentration (1×108 conidia/ml). These results indicated that the isolate can produce more conidia with cheap agricultural product and can develop as a microbial pesticide to control sweetpotato whitefly.

As the demand for large-scale analysis of gene expres- sion using DNA arrays increases, the importance of the surface characterization of DNA arrays has emerged. We com- pared the efficiency of molecular biological applications on solid-phases with different surface polarities to identify the most optimal conditions. We employed thiol-gold reactions for DNA immobilization on solid surfaces. The surface polarity was controlled by creating a self-assembled monolayer (SAM) of mercaptohexanol or hepthanethiol, which create hydrop- hilic or hydrophobic surface properties, respectively. A hyd- rophilic environment was found to be much more favorable to solid-phase molecular biological manipulations. A SAM of mercaptoethanol had the highest affinity to DNA mole- cules in our experimetns and it showed greater efficiency in terms of DNA hybridization and polymerization. The opti- mal DNA concentration for immobilization was found to be 0.5 mM. The optimal reaction time for both thiolated DNA and matrix molecules was 10 min and for the polymerase reaction time was 150 min. Under these optimized condi- tions, molecular biology techniques including DNA hybri- dization, ligation, polymerization, PCR and multiplex PCR were shown to be feasible in solid-state conditions. We de-monstrated from our present analysis the importance of surface polarity in solid-phase molecular biological appli- cations. A hydrophilic SAM generated a far more favorable envi- ronment than hydrophobic SAM for solid‐state molecular techniques. Our findings suggest that the conditions and met- hods identified here could be used for DNA‐DNA hybri- dization applications such as DNA chips and for the further development of solid-phase genetic engineering applicatio- ns that involve DNA-enzyme interactions.

In the present study, total methanol extracts prepared from Alpinia katsumadai showed significant protective effects against the oxidative stress induced by hydrogen peroxide, UV-C or γ-ray irradiation. These protective effects were substantially increased by treatment with 20~100 μg/ml of the extract. The A. katsumadai total methanol preparation was further fractionated into n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions. Among these five fractions, the ethylacetate and butanol fractions of A. katsumadai showed the strongest protective effects against oxidative stress induced by UV-C and γ-ray irradiation. These fractions also showed high DPPH radical scavenging and lipid peroxidation inhibitory activities. In addition, both fractions displayed cell proliferation activation effects, as evidenced by significant increases in colony formation. Our current data thus suggest that the mechanisms underlying the protective effects of A. katsumadai against oxidative damage may include radical scavenging, protection against cell membrane damage and stimulation of cell proliferation.