• Fisheries and Aquatic Sciences
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• v.26 no.2
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• pp.69-86
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• 2023

The bioactive secondary metabolites produced by sea cucumbers are very diverse with differences in composition, linkages, molecular weight, and various functional properties. Due to their physicochemical properties, these bioactive molecules in sea cucumbers have found applications in various market segments such as functional foods and cosmetics. Sea cucumber side dishes are a prominent food item in traditional cuisine in East Asian countries such as South Korea, China, and Japan. In addition, many studies have reported that the consumption of sea cucumbers can reduce the risk of cardiovascular disease, the pathogenesis of cancer cells, chronic inflammatory diseases, etc. In particular, many studies have recently reported the potential of sea cucumbers to develop functional products to reduce inflammation, oxidative stress, diabetes, and cancer. Additionally, these bioactive properties associated with sea cucumbers make them ideal compounds for use as functional ingredients in functional food products. However, no report has yet reviewed the properties of sea cucumbers related to functional foods. Therefore, in this review, the primary focus is given to collecting published scientific data (from 2019 to 2023) on the bioactive properties of sea cucumbers relevant to the functional food industry.

• Journal of Ecology and Environment
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• v.45 no.3
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• pp.143-151
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• 2021

Background: Plants are able to optimize defense responses induced by various herbivores, which have different feeding strategies. Local and systemic responses within a plant after herbivory are essential to modulate herbivore-specific plant responses. For instance, leaf-chewing herbivores elicit jasmonic acid signaling, which result in the inductions of toxic chemicals in the attacked leaf (tissue-specific responses) and also in the other unattacked parts of the plant (systemic responses). Root herbivory induces toxic metabolites in the attacked root and alters the levels of transcripts and metabolites in the unattacked shoot. However, we have little knowledge of the local and systemic responses against stem-boring herbivores. In this study, we examined the systemic changes in metabolites in the wild tobacco Nicotiana attenuata, when the stem-boring herbivore Trichobaris mucorea attacks. Results: To investigate the systemic responses of T. mucorea attacks, we measured the levels of jasmonic acid (JA), JA-dependent secondary metabolites, soluble sugars, and free amino acids in 7 distinct tissues of N. attenuata: leaf lamina with epidermis (LLE), leaf midrib (LM), stem epidermis (SE), stem pith (SP), stem vascular bundle (SV), root cortex with epidermis (RCE), and root vascular bundle (RV). The levels of JA were increased in all root tissues and in LM by T. mucorea attacks. The levels of chlorogenic acids (CGAs) and nicotine were increased in all stem tissues by T. mucorea. However, CGA was systematically induced in LM, and nicotine was systematically induced in LM and RCE. We further tested the resource allocation by measuring soluble sugars and free amino acids in plant tissues. T. mucorea attacks increased the level of free amino acids in all tissues except in LLE. The levels of soluble sugars were significantly decreased in SE and SP, but increased in RV. Conclusions: The results reveal that plants have local- and systemic-specific responses in response to attack from a stem-boring herbivore. Interestingly, the level of induced secondary metabolites was not consistent with the systemic inductions of JA. Spatiotemporal resolution of plant defense responses against stem herbivory will be required to understand how a plant copes with attack from herbivores from different feeding guilds.

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.540-549
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• 2021

The Wnt/β-catenin signaling pathway is involved in breast cancer and Myxococcus fulvus KYC4048 is a myxobacterial strain that can produce a variety of bioactive secondary metabolites. Although a previous study revealed that KYC4048 metabolites exhibit anti-proliferative effects on breast cancer, the biochemical mechanism involved in their effects remains unclear. In the present study, KYC4048 metabolites were separated into polar and non-polar (ethyl acetate and n-hexane) fractions via liquid-liquid extraction. The effects of these polar and non-polar KYC4048 metabolites on the viability of breast cancer cells were then determined by MTT assay. Expression levels of Wnt/β-catenin pathway proteins were determined by Western blot analysis. Cell cycle and apoptosis were measured via fluorescence-activated cell sorting (FACS). The results revealed that non-polar KYC4048 metabolites induced cell death of breast cancer cells and decreased expression levels of WNT2B, β-catenin, and Wnt target genes (c-Myc and cyclin D1). Moreover, the n-hexane fraction of non-polar KYC4048 metabolites was found most effective in inducing apoptosis, necrosis, and cell cycle arrest, leading us to conclude that it can induce apoptosis of breast cancer cells through the Wnt/β-catenin pathway. These findings provide evidence that the n-hexane fraction of non-polar KYC4048 metabolites can be developed as a potential therapeutic agent for breast cancer via inhibition of the Wnt/β-catenin pathway.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.1010-1019
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• 2021

Petroleum oil in reservoir has been acquired by primary, secondary and tertiary oil recoveries. Microbial enhanced oil recovery (MEOR) classified to tertiary oil recovery has been evaluated in two ways of in-situ and ex-situ options. In-situ MEOR injects microbes into a depleted oil reservoir and stimulates those to generate metabolites. Among metabolites, biosurfactants play an important role to make heavy residues flow. Ex-situ MEOR injects microbial metabolites instead of microbes into a reservoir to recover oil. Even though both in-situ MEOR and ex-situ MEOR are eco-friend processes, in-situ MEOR can be preferred because it is more economic. Even though MEOR have been evaluated for a long time, it is still in the state of evaluating in a pilot-scale. Among microbes, bacteria have been widely evaluated in MEOR purpose. In this paper, bacteria for MEOR were summarized and their metabolites were qualitatively evaluated.

• Journal of Ginseng Research
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• v.46 no.6
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• pp.790-800
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• 2022

Background: Panax ginseng Meyer is one of the most valuable medicinal plants which is enriched in anti-microbe secondary metabolites and widely used in traditional medicine. Botrytis cinerea is a necrotrophic fungus that causes gray mold disease in a broad range of hosts. B. cinerea could overcome the ginseng defense and cause serious leaf and root diseases with unknown mechanism. Methods: We conducted simultaneous transcriptomic and metabolomic analysis of the host to investigate the defense response of ginseng affected by B. cinerea. The gene deletion and replacement were then performed to study the pathogenic gene in B. cinerea during ginseng - fungi interaction. Results: Upon B. cinerea infection, ginseng defense responses were switched from the activation to repression, thus the expression of many defense genes decreased and the biosynthesis of antifungal metabolites were reduced. Particularly, ginseng metabolites like kaempferol, quercetin and luteolin which could inhibit fungi growth were decreased after B. cinerea infection. B. cinerea quercetin dioxygenase (Qdo) involved in catalyzing flavonoids degradation and ∆BcQdo mutants showed increased substrates accumulation and reduced disease development. Conclusion: This work indicates the flavonoids play a role in ginseng defense and BcQdo involves in B. cinerea virulence towards the P. ginseng. B. cinerea promotes disease development in ginseng by suppressing of defense related genes expression and reduction of antifungal metabolites biosynthesis.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.34-34
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• 2019

About 60% of the present drugs were developed from natural products with unique chemical diversity and biological activities. Hence, discovery of new bioactive compounds from natural products is still important for the drug development. On the other hand, breakthrough made in synthetic biology has also begun to supply us with many useful compounds through manipulation of biosynthetic gene for secondary metabolites. Theoretically, this approach can also be exploited to generate new unnatural compounds by intermixing genes from different biosynthetic pathway. Considering the potential, we are studying about bioactive compounds in natural sources, as well as the biosynthesis of natural products including engineering of the secondary metabolite enzymes to make new compounds in order to construct the methodological basis of the synthetic biology. In this symposium, engineering of secondary metabolite enzymes that are involved in the biosynthesis of plant polyketides to generate new compounds in our laboratory will be mainly introduced.

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1206-1211
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• 2013

The selective inhibition of PTP1B has been widely recognized as a potential drug target for the treatment of type 2 diabetes and obesity. In the course of screening for PTP1B inhibitory fungal metabolites, the organic extracts of several fungal species isolated from marine environments were found to exhibit significant inhibitory effects, and the bioassay-guided investigation of these extracts resulted in the isolation of fructigenine A (1), cyclopenol (2), echinulin (3), flavoglaucin (4), and viridicatol (5). The structures of these compounds were determined mainly by analysis of NMR and MS data. These compounds inhibited PTP1B activity with 50% inhibitory concentration values of 10.7, 30.0, 29.4, 13.4, and 64.0 ${\mu}M$, respectively. Furthermore, the kinetic analysis of PTP1B inhibition by compounds 1 and 5 suggested that compound 1 inhibited PTP1B activity in a noncompetitive manner, whereas compound 5 inhibited PTP1B activity in a competitive manner.

• Research in Plant Disease
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• v.23 no.2
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• pp.89-98
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• 2017

Ralstonia solanacearum species complex (RSSC) causes bacterial wilt, and it is one of the most important soil-borne plant pathogenic bacteria. RSSC has a large host range of more than 50 botanical families, which represent more than 200 plant species, including tomato. It is difficult to control bacterial wilt due to following reasons: the bacterial wilt pathogen can grow inside the plant tissue, and it can also survive in soil for a long period; moreover, it has a wide host range and biological diversity. In most previous studies, scientists have focused on developing biological control agents, such as antagonistic microorganisms and botanical materials. However, biocontrol attempts are not successful. Plant-derived metabolites and extracts have been promising candidates to environmentally friendly control bacterial wilt diseases. Therefore, we review the plant extracts, essential oils, and secondary metabolites that show potent in vivo antibacterial activities (in potted plants or in field) against tomato bacterial wilt, which is caused by RSSC.

• Journal of Veterinary Clinics
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• v.33 no.2
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• pp.138-141
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• 2016

The aim of this study was to diagnose the fertility of a female western lowland gorilla kept in Seoul Zoo, in accordance with age by analyzing the fecal sex hormone metabolites. The study was conducted in two period of times, when the animal was from 35 to 37 years old and when the animal was from 40 to 42 years old. Non-invasive method by using fecal samples was used for safe and efficient fertility diagnosis. We collected the feces from the enclosure at least three times a week. Then $17{\beta}$-estradiol and progesterone, which are fecal sex hormone metabolites, were measured by time-resolved fluoro-immunoassay to compare the menstruation cycle and the annual reproductive cycle. For the duration of the primary study (when the animal was 35~37 years old), irregular menstruation and high concentrations of estradiol and progesterone were observed. However, menstruation was hardly observed and the concentrations of both hormones were statistically very low in the period of secondary study (when the animal was 40~42 years old). This observed phenomenon in our study was very comparable to menopause in adult women; therefore, it was confirmed that our female gorilla has reached menopause because of the natural aging, as they become older.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.230-239
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• 2022

Holostemma annulare (Family Asclepiadaceae) is an invaluable vulnerable medicinal plant; the root tubers are used in Ayurveda medicine and by folk healers to treat various ailments. In this study, Schenk and Hildebrandt medium fortified with the cytokinins 6-benzyl adenine, kinetin, and auxins, including indole 3-butyric acid, indole 3-acetic acid, α-naphthaleneacetic acid, and 2,4-dichlorophenoxyacetic acid, were checked for their efficiency on root tuber induction from different explants. Adventitious root tubers were more successfully induced from in vitro leaf segments and shoots when cultured in Schenk and Hildebrandt medium supplemented with 0.5 mg/l of α-naphthaleneacetic acid. In addition, preliminary phytochemical analysis of in vitro root tubers and identification of different secondary metabolites were conducted. Thin layer chromatography and high performance thin layer chromatography analysis of the crude methanolic extracts of the in vitro root tuber identified the presence of lupeol, a bioactive triterpene. Adventitious root tuber induction offers a novel method for the in vitro production of bioactive metabolites that can be scaled up by bioreactors, thus ensuring the conservation and sustainable utilization of H. annulare. The study warrants further scale-up production and pharmacological investigation that can be extended for pharmaceutical needs.