Current investigations provide a comprehensive understanding of the occurrence and biodiversity of plant-parasitic nematodes (PPNs) in the major citrusproducing regions of Jeju Island, South Korea. Our survey identified five genera and five species of PPNs from 82 infested Citrus unshiu field samples collected across 116 sites in the Jeju provinces. Community analysis revealed the highest prevalence of PPNs (39.02%) at Namwon-eup, significantly driven by Tylenchulus semipenetrans, followed by Paratylenchus sp., Helicotylenchus sp., Meloidogyne sp., and Pratylenchus sp. Data indicate that all 82 sites were infested with T. semipenetrans (70.68%), marking a considerable increase in prevalence compared to previous surveys and posing a significant threat to citrus cultivation. The study results also demonstrate the influence of soil type on PPNs communities, revealing correlations between soil texture and nematode diversity. Citrus orchards cultivated in black clay loam soil exhibited significant PPN infestations. Overall, the PPN survey underscores the economic importance of monitoring citrus nematode infection rates and maintaining economic threshold levels in citrus production. It also emphasizes the need for developing effective management strategies to control PPNs, which are essential for maintaining crop yield and ensuring agricultural sustainability.

In this study, in order to develop an foaming tablet product using yuzu powder, yuzu powder was manufactured using different drying methods such as freeze-drying, 60℃ drying, and 40℃ drying, and then quality characteristics and functionality were analyzed. The naringin content per g of yuzu powder was 8.9 mg for freeze-drying and 8.8 mg for 60℃ drying, and the hesperidin content per g of yuzu powder was highest at 53.6 mg for freeze-drying and 46.2 mg for 60℃ drying. followed by 40℃ drying (41.7 mg). The tyrosinase inhibitory activity of 60℃ dried powder was found to be twice as high as that of freeze dried powder. Accordingly, in order to develop an inner beauty product, foaming tablets were manufactured using hot air dried powder, and the quality characteristics and functional ingredients of the final foaming tablets were investigated. The foaming tablet prepared with yuzu powder content of 10 and 15% showed an inhibitory activity of tyrosinase of 73.7 %, which was 1.6 times higher than that of ascorbic acid (1 mM), which was a positive control, confirming its melanin production inhibition effect.

The purpose of this study was to investigate the effects of sterilization, storage period and washing yuzu, according to the washing method, during the storage period. The results showed that the fungus size increased as the storage period increased, and no mold occurred in the yuzu washed with ozone water until 20 days. After 30 days of storage, a mold of 124.1±13.9 mm2 was observed. The no-treatment sample had a fungus of 814.5±72.8 mm2 in size on day 0 and the fungus the largest fungus was 6,362±636.7 mm2 on day 30. In the case of water treatment, the fungus was 286.4±31.5~4,836.4±484.6 mm2 in size. The results of the study confirmed that washing yuzu with ozone water has a sterilizing effect.

본 연구는 복합추출물(익모초, 어성초, 진피)의 생리활성을 측정하여 식·의약품, 화장품 등의 소재로서의 가능성을 확인하고자 하였다. 복합추출물은 열수 추출하였으며, 세포독성, 항산화, 항염증, MAPKs 등의 평가는 ELISA 및 western blot을 통해 확인하였다. 그 결과, 총 폴리페놀 함량은 35.53±0.48 ㎎ GAE/g, 플라보노이드 함량은 8.18±0.16 ㎎ QE/g으로 나타났으며, DPPH 와 ABTS radical 소거능은 농도 의존적으로 증가하였다. 대조군과 비교하여 세포독성은 400 ㎍/㎖ 농도까지 100% 이상의 생존율이 나타났으며, NO 및 염증성 사이토카인을 유의하게 감소시켰다. 또한, 복합추출 물은 MAPKs(ERK, JNK, p38) 단백질 발현을 유의하게 억제시켰다. 이러한 결과는 복합추출물이 산화 적 손상 및 염증에 사용될 수 있음을 나타낸다. 따라서 본 연구 결과는 식·의약품, 화장품용 복합소재의 의 기초자료로 활용될 수 있을 것이다.

To investigate the functional activity of different citrus fruit peels, antioxidant compounds in 70% ethanol extracts of mandarin, lemon, orange, and grapefruit peel powders were identified, and antioxidant and antibacterial activities were quantitated. Mandarin peel contained the highest content of total phenolic compounds and total flavonoid substances (21.46±0.12 mg GAE/g and 11.57±0.05 mg RE/g, respectively). The total phenolic compound content of the three other citrus fruits was 14.16±0.18-18.44±0.07, and their total flavonoid content was 5.51±0.10-7.46±0.09 mg RE/g. DPPH radical scavenging activity was the highest in lemon peel (87.64±0.21%), and mandarin peel displayed the best antioxidant activity with respective ABTS radical scavenging activity and FRAP measurements of 43.20±0.61% and 78.82±1.06 mM TE/g. Grapefruit peel antimicrobial activity increased with treatment time, and was the most potent among the four tested citrus species, inhibiting Staphylococcus aureus by about 4.05 log cycle. These findings demonstrate that mandarin and grapefruit peel can be used to prevent oxidation, improve food storage capabilities, and potentially preserve food quality.

본 연구에서는 감귤원에서 초생재배 유무(초생재배 W, 제초제 살포 NW)와 합성피레스로이드계 살포유무(살포 P, 무살포 NP)에 따른 귤 응애의 개체군 동태를 구명하고자 수행되었다. 두 가지 기본적인 가설로 1) 초생재배는 천적의 서식처를 제공하여 천적의 정착을 높이므로 귤응 애의 발생을 감소시키는 요인으로 작용하며, 2) 합성피레스로이드계는 천적을 제거하여 귤응애의 밀도를 증가시키는 요인으로 가정하였다. 관측 된 천적 개체군(주로 이리응애류와 마름응애류)의 발생은 가정에 근거한 기대치와 크게 다르지 않았다. 2011년의 경우 NW+NP 처리구와 W+NP 처리구에서 차이가 있었으나, 2012년 실험에서는 기대치와 관측치가 거의 일치하였다. 전체적으로 약제효과가 뚜렷하게 나타나서 합성 피레스로이드계 살포시 천적이 유의하게 감소하였다. 잡초효과는 엇갈리는 결과를 보였는데, 봄-유래 여름 개체군 대비 가을 개체군의 증가 등을 고려할 때 초생재배를 하는 경우 천적의 발생이 증가하였다. 다만, 합성피레스로이드계 살포구에서 귤응애가 감소하는 비이상적인 결과는 귤응 애의 합성피레스로이드계에 대한 강한 기피성을 전제로 해석할 수 있었다.

귤굴나방은 제주도 감귤원에서 경제적으로 중요한 해충이지만, 상대적으로 월동생태와 관련된 연구는 부족하다. 본 연구에서는 귤굴나방이 월동과 관련하여 다음 해 초기개체군 발생과 어떻게 연결되는지 발육단계별 저온 실내실험과 야외실험 및 노지 감귤원 포장조사를 통하여 구명하였다. 연구 결과, 동일한 저온 조건에서 귤굴나방의 발육단계에 따라 생존기간의 유의한 차이가 있었으며 성충이 번데기보다 더 오래 생존하는 것으로 나타났다. 귤굴 나방 성충과 번데기를 야외 감귤원에 접종한 후 생존기간을 평가한 결과, 서귀포지역에서 성충은 다음 해 3월 24일까지 생존하였다. 이는 일반적으로 서귀포지역의 봄순 발아가 3월 중순에 시작된다는 사실을 고려했을 때 성충태로 월동한 귤굴나방이 다음 해 초기개체군을 형성할 가능성이 높다는 것을 의미한다. 반면에 번데기의 경우 제주시와 서귀포에서 1월을 넘기지 못하고 모두 사망하였다. 또한, 노지 감귤원 내 귤굴나방 발육단계별 밀도조사에서 다음 해 봄까지 노지 감귤원에서 생존한 번데기는 없었던 반면 성충은 모든 과원에서 지속적으로 발견되었다. 따라서 결과를 종합하여 판단해 볼 때, 제주도의 노지 감귤원에서 귤굴나방은 성충태로 월동하는 것으로 판단되며, 번데기의 경우 신초에 형성된 용방에서만 생존할 수 있다는 제약이 있기 때문에 겨울철 동해 피해를 받기 쉬운 신초에서 월동 후 다음 해 초기개체군 형성에 기여하는 것은 쉽지 않을 것으로 판단된다.

This study was designed to investigate the intracellular signaling pathways and immunoenhancing effect of macrophage activation by crude polysaccharides (CPP) extracted from citrus peels. CPP did not affect the cytotoxicity of RAW264.7 cells, but showed dose-dependent effects on cell viability. Also, CPP showed high production of chemokine (nitric oxide (NO)) and cytokines (interleukin (IL)-6 and tumor necrosis factor (TNF)-α). CPP increased IL-6, TNF-α, and inducible nitric oxide synthase (iNOS) mRNA expression dose-dependently. CPP also strongly induced the phosphorylation of the ERK, p38, and IκBα pathways in RAW 264.7 cells. In anti-pattern recognition receptors (PRRs) experiments, the effect of CPP on NO production was strongly suppressed by neutralizing toll-like receptor (TLR)2, TLR4, and Dectin1 antibodies, whereas IL-6 and TNF-α production by CPP was mainly suppressed by mannose receptor (MR). Therefore, these results suggest that CPP treatment-induced NO production was regulated by the ERK, p38, and NF-κB pathways through TLR2, TLR4, and Dectin1 receptors, whereas IL-6 and TNF-α production was primarily regulated by the ERK, p38, and NF-κB pathways through MR receptors.