Many insects form mutualistic relationships with microbial symbionts, crucial for their physiological processes. The bean bug, Riptortus pedestris, establishes a unique gut symbiosis with the genus Caballeronia and consistently acquires these symbionts from surrounding soil with each generation. As a result, the bean bug unavoidably consumes a variety of environmental microbes, including potential pathogens. To address this, the bean bug has developed a specialized organ in its midgut that selectively filters out non-symbiotic microbes, thereby preventing contamination of its symbiotic organ. In this study, we identified a pathogenic strain from the genus Burkholderia that lethally affects the bean bug post-invasion of the symbiotic organ. This pathogen employs a strategy of mimicking the motility of native symbionts to infiltrate the symbiont sorting organ and displays a pronounced resistance against antimicrobial agents produced by the host. Upon establishing itself in the symbiotic organ, the pathogen breaches the midgut cells, leading to host mortality, and subsequently disperses into the external environment. Our findings unveil a cunning pathogenic tactic that exploits the mimicry of native symbionts within an insect's symbiotic framework.

Many insects possess symbiotic microorganisms in their bodies, wherein host-symbiont intimate interactions occur. Despite recent advances in omics technology, the molecular bases of the symbiotic associations remain unclear. The bean bug Riptortus pedestris harbors an environmentally acquired Burkholderia symbiont in their midgut crypts. Unlike other insect symbionts, the Burkholderia symbiont is easily culturable and genetically manipulatable outside the host insect. In conjunction with the experimental advantages of the bean bug, the Riptortus–Burkholderia association is an ideal model system for approaching the molecular bases underpinning insect-microbe symbioses. In this presentation, the current knowledge of this model system is summarized.

Recent studies suggested that gut symbionts modulate insect development and reproduction. However, how gut symbionts modulate host physiologies and what types of molecules are involved in these changes are still unclear. When we analyzed hemolymph proteins and transcriptional levels of host insects, hexamerin-α (Hex-α), hexamerin-β (Hex-β) and vitellogenin-1 (Vg-1) were highly expressed in symbiotic insects (Sym) compared to aposymbiotic insects (Apo). Depletion of Hex-β by RNA interference in 2nd Sym-nymphs delayed adult emergence, whereas Hex-α and Vg-1 RNA interference in 5th nymphs decreased reproduction of female insects and caused loss of color of laid eggs. Also, the levels of JHSBIII of Riptortus host were 3-fold higher in the Sym-female insects compared to the Apo-insects. These results demonstrate that the Burkholderia gut symbiont modulates host development and egg production through regulating the expression of three host storage proteins by controlling of brain hormone.

Symbiotic bacteria are common in insects. Because symbiotic bacteria are known to intimately affect the various aspects of insect host biology, ideally insects can be controlled by manipulating their symbiont. However, the attempts to control insects through their symbiont have been very limited. The paucity of the insect pest control using their symbiont is most likely due to the poor understanding of the symbiotic interactions between host insect and symbiont, which is attributed to the difficulty in cultivation of insect symbionts. However, the recently established bean bug, Riptortus pedestris, symbiotic system provides good opportunities to study insect’s symbiont in molecular level through their cultivable symbionts. Bean bugs acquire genus Burkholderia cells from environment and harbor them as their gut symbionts in the specialized posterior midgut. The genome of the Burkholderia symbiont was sequenced, and the genomic information has been used to generate the genetically manipulated Burkholderia symbiont strains. After orally administering the mutant Burkholderia symbionts into bean bugs for symbiotic association, the bacterial colonization levels in the host gut and host phenotypes were analyzed. As a result, we have identified novel symbiotic factors necessary for establishing successful association with host. Our recent understandings on the bacterial symbiotic factors demonstrate a great possibility to control the bean bug pest using genetically modified Burkholderia symbiont.

The Riptortus pedestris-Burkholderia symbiotic system is a promising model for understanding molecular mechanism of symbiosis. In previous studies, the Burkholderia symbiont has been shown to play important biological roles in the growth and fitness of host R. pedestris. The Burkholderia symbiont, one of bacteria found in the soil, is the only bacterium that can colonize the symbiotic midgut region of R. pedestris. However, the molecular mechanism of host selectivity for the Burkholderia symbiont remains unknown. To determine where the selection occurs, we firstly compared initial infectivity of different mid-gut regions after oral infection of Escherichia coli and Burkholderia. Interestingly, E. coli were not detected in any regions of mid-gut, while Burkholderia could reach to the posterior region of mid-gut. Therefore, we hypothesized that host selectivity for the Burkholderia symbiont is occurred in the salivary gland. To address this hypothesis, we treated E. coli and Burkholderia with lysate of salivary gland and examined their survival by estimation of colony forming unit (CFU) on the plate. We found that E. coli, but not Burkholderia, was susceptible to the lysate of salivary gland. To determine molecular basis of the selective mechanism in the salivary gland, we analyzed antimicrobial proteins (AMPs) from lysate of salivary gland. we identified three AMPs, namely rip-trialysin1, rip-trialysin2 and lysozyme and further purified rip-trialysin1 and rip-trialysin2. When E. coli and Burkholderia were treated with rip-trialysin1 and rip-trialysin2, rip-trialysin1 exhibited little antimicrobial activity, but rip-trialysin2 exhibited antimicrobial activity. Furthermore, we found that E. coli was susceptible, but Burkholderia is resistant to commerciallypurchased egg white lysozyme. Our results suggest that R. pedestris salivary gland provides a chance of selection for the Burkholderia symbiont and lysozyme in salivary gland seems to play an important role for the selection of gut symbiont.

The Riptortus (stinkbug) has a specialized symbiotic organ, M4 midgut, to harboring symbiont Burkholderia. M4 midgut is located in abdomen and surrounded with insect hemolymph. Recently our group demonstrated that symbiotic Burkholderia showed different physiology after adapting in M4 gut compare with in vitro cultured Burkholderia. And population of symbiotic Burkholderia in the M4 midgut is regulated by special organ. However, the molecular mechanism to prevent spreading and migrating symbiont bacteria to other host tissues from symbiotic organ is not clear. Therefore, we assumed that symbiont Burkholderia are susceptible to host humoral immunity after established infection in M4 midgut to prevent spreading and migrating into the other host tissues through Riptortus hemolymph. To prove this assuming, we tested the susceptibility and survival rate of symbiont Burkholderia in hemolymph of Riptortus in vitro and in vivo. We also examined the susceptibility of symbiont Burkholderia using purified antimicrobial peptides (AMP), pyrrhocoricin-like, thanatin-like and defensin-like AMPs. Finally, we tested inducing ability for AMPs by systemic infection of symbiotic Burkholderia. Gene expression of purified AMPs was not different after systemic infection of both symbiont and in vitro cultured Burkholderia. Surprisingly, in vitro cultured Burkholderia resisted on bacteria injected hemolymph and purified AMPs but symbiont Burkholderia were highly susceptible in bacteria injected hemolymph and purified AMP. These results suggest that symbiont Burkholderia can't survive in the hemolymph after escaping symbiotic organ. Moreover, humoral immunity of host Riptortus is important to prevent spreading and migrating symbiont Burkholderia into the other host tissue or organ from symbiotic organ.

Many previous ecological studies on three major bacterial symbionts and a newly discovered symbiont PAXS (pea aphid X-type symbiont) in the pea aphid Acrythosiphon pisum have shown that these symbionts are associated with the expression of a variety of host phenotypes, including resistance to parasitoid Aphidius ervi and tolerance to heat stress. The principal role of all four symbionts “Candidatus Serratia symbiotica”, “Candidatus Hamiltonella defensa”, “Candidatus Regiella insecticola”, and PAXS is to protect aphids against abiotic stress by preserving the cells in which most of symbionts dwell and by reducing the rate of parasitism. In this experiment, we detected endosymbionts from four aphid clones by means of genomic DNA extraction, PCR with gene specific primer, and restriction enzyme cutting. The patterns of PCR and restriction enzyme cutting were all identical in the four aphid clones. In order to specifically identify the endosymbiont, we searched the sequences using BLAST. The BLAST search revealed that nucleotide sequences of the symbiont were 98% identical to Serratia entomophil. S. entomophil is also known to provide tolerance to heat stress, resistance to parasitoid wasps, and restoration of reproduction in aphids, suggesting its role in host protection.

대두(大豆)-근류균(根瘤菌)의 공생(共生)에서 숙주식물(宿主植物)의 Root Exudate에 대한 근류균(根瘤菌)의 화학주성(化學走性)이 근류형성(根瘤形性)(숙주식물(宿主植物))에 미치는 영향(影響)을 밝히기 위해 연구(硏究)한 결과(結果)는 다음과 같다. 대두(大豆) Seed Lectin은 품종간(品種間) 차이(差異)가 없었으며 분자량(分子量) 120,000정도(程度)의 4개(個)의 동일(同一)한 subunit를 가지는 물질(物質)이며, Pea Seed Lectin은 분자량(分子量) 44,000정도(程度)이며 15,000과 7,000정도(程度)의 두 종류(種類)의 subunit를 가지는 물질(物質)이며 대두(大豆) lectin은 표준 lectin 항체와 침강선을 형성하였다. 그러나 완두의 lectin은 표준 lectin과 항원-항체반응이 없었으므로 두 lectin은 동일 항원이 되지 않아 서로 다른 물질이었다. 팔달의 Crude Root Exudate에 대(對)한 근류균(根瘤菌)의 화학주성(化學走性) 비(比)는 KCTC 2422는 각각(各各) 3.5이고 LPN-100은 1.4이며 LCR-101은 각각(各各) 1.4이었다. 뿌리분비물의 각 fraction에 대한 근류균의 화학주성은 중성분획이 가장 높고 양성분획이 그다음이며 음성분획이 가장 낮은 화학주성을 나타내어 각물질에 대한 근류균의 친화도에 차이가 있었다. 근류형성(根瘤形性)의 정도(程度)는 KCTC 2422의 경우(境遇)는 접종(接種)후 7日경부터 Nitrogenase Activity가 나타났으며 LCR-101는 15일 이후(以後)에 Nitrogenase Activity를 나타내었다. LPN-100은 Nitrogenase Activity가 전혀 나타나지 않아 근류균(根瘤菌)의 화학주성(化學走性)이 숙주인식과정(宿主認識過程)에 영향(影響)을 미쳤음을 확인(確認)할 수 있었다.

Industrial symbiosis (IS) activities within an industrial complex can enhance environmental and economic efficiencies. This study proposed a simplified life cycle assessment (LCA) methodology as an effective tool with which to evaluate the reduction of environmental impact of IS activities. In this method, the variation of resources and energy consumptions before and after IS activities are proposed to simply evaluate its lifecycle environmental impacts. The simplified LCA was applied to an IS case between an industrial waste incineration plant and a steam production plant of a paper mill firm in the metropolitan city Ulsan. The system boundary and inventory were set for this IS, and an environmental impact assessment was carried out by standard and proposed LCA methods. The results showed that the environmental impacts after IS decreased in all impact categories with regard to the consumption reduction of boiler fuel used at the paper mill. Furthermore, the performance of environmental improvement activities such as IS can be simply evaluated by only considering the input and output changes in the environmental improvement activities. In this IS case study, the environmental impact was decreased by 11.7% (weighted impact base). This was due to the utilization of waste heat generated from an incineration plant in the process of the paper mill firm.

제21차 파리 기후변화협약 당사국총회(COP21)에서 신기후변화체제인 파리협정이 채택되었으며, 파리협정은 각 국가가 국가별 기여방안(INDC)을 스스로 정하여 매 5년마다 상향된 감축 목표를 제출하도록 하고 있다. 우리나라는 2030년 총 국가 배출량 전망치(BAU) 대비 37%를 감축하겠다는 내용의 국가별 기여방안을 UN에 제출하였다. 이러한 국제 및 국내 환경은 온실가스 배출 및 감축량 산정의 중요성을 부각시키며, 국내의 다수의 기업들은 온실가스 배출의 감축을 위하여 부산물, 폐수, 에너지 등을 교환하는 산업공생을 진행하고 있다. 산업공생은 공급기업, 수요기업 등의 다수의 이해당사자가 관련되어 있으므로, 산업공생으로 발생하는 온실가스 감축 크레딧의 할당이 중요하다. 현재 우리나라의 경우 온실가스 감축 크레딧을 기업의 경계를 기준으로 부여 및 할당하고 있으며, 이와 같은 방법은 전체적인 온실가스의 발생량은 저감시킬 수 있으나, 산업공생에 기여한 일부 이해당사자의 온실가스 배출량을 오히려 증가시킬 수 있는 문제점이 발생한다. 이러한 결과는 산업공생을 추진하는데 있어 커다란 장애요인으로 온실가스 감축노력을 활성화시키기 위해 산업공생 활동이 활발히 일어나도록 온실가스 감축 크레딧의 할당에 대한 제도개선이 필요하다. 산업공생에 의하여 발생하는 온실가스 감축 크레딧은 산업공생과 관련된 이해당사자들의 노력에 의한 결과이므로 총량범위 내에서 상호협의하여 할당하는 유연성을 가지도록 제도개선이 필요하다고 판단된다. 한편, 본 연구에서는 울산광역시에서 현재 이루어지고 있는 실제 산업공생사례를 대상으로 연구를 수행하였다.

This work aimed to analyze current status of by-products generation and industrial symbiosis network in Gyeongsangbuk-do, South Korea. Manufacturing sector of the province mainly consists of electronics, machinery, steel, metal-working industries. Gumi and Pohang have the 1st and 2nd largest worker population in the manufacturing sector. 21,950.7 ton/d of waste is generated from the industries in 2011, of which 82.2% is recycled. The industrial waste, which is not recycled, is mainly composed of sludge cake from domestic wastewater treatment plants, waste plastic, incinerator ash, and slag. Pohang is the largest generating city of both total and the non-recycled industrial waste in the province, and most of the waste is from Pohang steel industrial park. Symbiosis map in Pohang steel industrial park shows that most of the current material symbiosis in the industrial park is for waste refractories and slag.

Reuse, recycling and recovery (3R) of industrial wastes are common and encouraging in Korea. Industrial symbiosis is one of typical methods for implementing 3R and has been defined as engaging “traditionally separate industries in a collective approach to competitive advantage involving physical exchange of materials, energy, water, and by-products”. The keys to industrial symbiosis are collaboration and the synergistic possibilities offered by geographic proximity. Recently, several countries in East Asia such as Taiwan, South Korea, Japan and China are promoting ‘designed’ symbiosis networks in various industrial complexes based on their national Eco-industrial Park (EIP) demonstration programs. Despite the recently promoted EIP initiatives worldwide, only very few studies furnish the operational and functional details of ‘designed’ industrial symbiosis networks, starting from the planning to implementation stage. The production of terephthalic acid (TPA) in Korea is 6.5 million ton based on 2011. The production of waste generated in the process of TPA is about 15,000 ton/yr and included useful materials like residue TPA as well as isophthalic acid (iPA), benzoic acid (BA) and p-toluic acid (p-TL). Until now, TPA waste was incinerated due to high caloric value. This study was conducted for recovery of valuable materials from industrial waste and utilization of recovered material as an example of Korean EIP. In this study, the experiment was performed to separate above four materials from the waste by solvent (methanol and water) extraction. The solubility of TPA (0.1g/100g) for methanol is relatively low compared to other materials. Also the solubility of BA (68g/L at 95℃) and p-TL (11.6g/L at 98℃) for water is relatively high in comparison with other materials. Finally, BA was separated from p-TL by molecular distillation system. The purity of recovered materials was analyzed by ultra-high performance liquid chromatography (Waters Xevo TQ system). The recovery rate and purity of BA is 90% and 93%. The recovered BA could be recycled the companies which are produced plastic plasticizer and paints.

Eco-efficiency considers both environmental impacts and economic values. It is a useful tool for communicating with stakeholders for business decision making. This study evaluated the eco-efficiency factor (EEF) for the energy network of a dyeing company that supplies surplus heat to a neighboring apartment during the night. This symbiosis network is one of the eco-industrial park (EIP) projects in Korea and aims to benefit local residents and the industrial complex by utilizing surplus heat. In this study, two categories were annualized. The first quantified environmental burden based on CO2 emissions and quantified product value in terms of steam sales. The second used a variety of environmental factors, such as fossil fuel, water and waste, to quantify environmental burden and used steam sales to quantify value. The EEF of the symbiosis network was 1.6, using the global warming impact, and determined using the multiple variable, was 1.33. This study shows that the EEF depends on variable details of environmental burden but the values of this project were very high contrast to other business or EIP project.

This study is focused on the industrial symbiosis based on industrial ecosystem theory. At first, the concept of industrial ecosystem was introduced. Industrial symbiosis is a good tool in order to make a harmony between industry and natural ecosystem. The good example of industrial symbiosis is the case of Kalundborg in Denmark, where 11 networks are working in four enterprises and one community nearby. It was proved that savings of natural resources and economic benefit are achieved by use of industrial symbiosis. Moreover, the control of pollutant emission was also done by use of advanced technology and investments. Based on this case, It was shown that industrial symbiosis through eco-industrial complex in Korea was confronted with many difficulties. First of all, loose emmision criteria, recycling system on wastes, and the absence of will for industrial symbiosis should be solved in Korea.