• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1290-1302
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• 2016

Microalgae are being researched for their potential as attractive biofuel feedstock, particularly for their lipid production. For maximizing biofuel production, it is necessary to explore the effects of environmental factors on algal lipid-producing potential. In this study, the effects of nitrogen (N) sources (NO₂-N, NO₃-N, urea-N, NH₄-N, and N-deficiency) and carbon-to-nitrogen ratios (C/N= 0, 1.0, 3.0, and 5.0) on algal lipid-producing potential of Chlorella sp. HQ were investigated. The results showed that for Chlorella growth and lipid accumulation potential, NO₂-N was the best amongst the nitrogen sources, and NO₃-N and urea-N also contributed to algal growth and lipid accumulation potential, but NH₄-N and N-deficiency instead caused inhibitory effects. Moreover, the results indicated that algal lipid-producing potential was related to C/N ratios. With NO₂-N treatment and carbon addition (C/N = 1.0, 3.0, and 5.0), total lipid yield was enhanced by 12.96-20.37%, but triacylglycerol (TAG) yields decreased by 25.52-94.31%. As for NO₃-N treatment, carbon addition led to a 17.82-57.43%/25.86-82.67% reduction of total lipid/TAG yields. When NH₄-N was used as the nitrogen source, total lipid/TAG yields were increased by 46.67-113.33%/28.99-74.76% with carbon addition. The total lipid/TAG yields of urea-N treatment varied with C/N ratios. Overall, the highest TAG yield (TAG yield: 38.75 ± 5.21 mg/l; TAG content: 44.16 ± 4.35%) was achieved under NO₂-N treatment without carbon addition (C/N = 0), the condition that had merit for biofuel production.

• Journal of Nutrition and Health
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• 제55권1호
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• pp.70-84
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• 2022

Purpose: Skeletal muscles display significant heterogeneity in metabolic responses, owing to the composition of metabolically distinct fiber types. Recently, numerous studies have reported that in skeletal muscles, suppression of genes related to fatty acid channeling alters the triacylglycerol (TAG) synthesis and switches the energy substrates. However, such responses may differ, depending on the type of muscle fiber. Hence, we conducted in vitro and animal studies to compare the metabolic responses of different types of skeletal muscle fibers to the deficiency of fatty acyl-CoA synthetase (Acsl)6, one of the main fatty acid-activating enzymes. Methods: Differentiated skeletal myotubes were transfected with selected Acsl6 short interfering RNA (siRNA), and C57BL/6J mice were subjected to siRNA to induce Acsl6 deficiency. TAG accumulation and expression levels of insulin signaling proteins in response to acute glucose supplementation were measured in immortalized cell-based skeletal myotubes, oxidative muscles (OM), and glycolytic muscles (GM) derived from the animals. Results: Under conditions of high glucose supplementation, suppression of the Acsl6 gene resulted in decreased TAG and glycogen synthesis in the C2C12 skeletal myotubes. The expression of Glut4, a glucose transporter, was similarly downregulated. In the animal study, the level of TAG accumulation in OM was higher than levels determined in GM. However, a similar decrease in TAG accumulation was obtained in the two muscle types in response to Acsl6 suppression. Moreover, Acsl6 suppression enhanced the phosphorylation of insulin signaling proteins (Foxo-1, mTORc-1) only in GM, while no such changes were observed in OM. In addition, the induction ratio of phosphorylated proteins in response to glucose or Acsl6 suppression was significantly higher in GM than in OM. Conclusion: The results of this study demonstrate that Acsl6 differentially regulates the energy metabolism of skeletal muscles in response to glucose supplementation, thereby indicating that the fiber type or fiber composition of mixed muscles may skew the results of metabolic studies.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2023년도 임시총회 및 춘계학술대회
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• pp.46-46
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• 2023

It has been reported that Rosa acicularis has anti-obesity activity by inhibiting the digestive lipase activity. However, there is a lack of clear in vitro studies regarding the anti-obesity activity of Rosa acicularis. Therefore, in this study, we aimed to verify the anti-obesity activity of Rosa acicularis leaves (RAL) and elucidate its mechanism of action in 3T3-L1 preadipocytes. RAL dose-dependently inhibited the accumulation of lipid droplets and triacylglycerol. RAL had no effect on cell proliferation and survival in undifferentiated 3T3-L1 cells, but it inhibited cell proliferation in differentiating 3T3-L1 cells. RAL increased ATGL, p-HSL, and HSL, and decreased perilipin-1 in differentiating 3T3-L1 cells. In addition, RAL reduced lipid droplet accumulation and increased free glycerol content in differentiated 3T3-L1 cells. RAL increased ATGL and HSL in differentiated 3T3-L1 cells. Also, RAL increased p-AMPK, PPARγ, UCP-1, and PGC-1α in differentiating 3T3-L1 cells. AMPK inhibition by Compound C attenuated RAL-mediated increase of ATGL, HSL, PPARγ, and UCP-1 in 3T3-L1 cells. Taken together, it is thought that RAL may inhibit lipid accumulation through lipolysis and thermogenesis via the activation of AMPK in adipocytes.

• Journal of Plant Biotechnology
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• 제38권4호
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• pp.241-250
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• 2011

식물유의 거의 대부분은 triacylglycerol (TAG) 형태로 종자에 축적되어있으며 이는 종자가 발아할 때에 필수적인 에너지공급원이자 동물과 인간들에게 필수지방산과 중요한 에너지원이다. 최근 식용유의 건강기능성으로 수요증가와 더불어 바이오디젤과 산업원료 등의 산업적 수요도 증가함에 따라 더욱 중요한 자원이 되고 있다. 그래서 생명공학기술로 종자유의 함량을 증진하고자 하면 지질 생합성에 탄소의 유입에 관여하는 조절 유전자를 과발현 또는 억제하는 것이 결정적으로 중요하다. 본 총설에서는 지질함량에 영향을 미치는 것으로 여겨지는 후보 유전자들에 대해 기술하고 이들의 지방 함량 증대 가능성을 조사하였다. 식물의 지방산의 생합성과 종자유의 축적에 관여하는 유전자들은 크게 구분하자면 첫째, TAG가 생합성되기 위해 필요한 전구체를 합성하는 유전자, 둘째, 지방산합성과 TAG 축적에 관여하는 유전자, 셋째, 종자 발달과 종자유 축적에 관여하는 전사인자 유전자가 있다. 종자유 함량을 결정하는 대사들은 앞에서 언급했듯이 매우 복잡하기 때문에 최근에 전사인자의 조절이 다수의 지방생산 대사 유전자를 동시 조작하여 형질전환 식물에서 종자유 함량이 증진하는 것보다 더 바람직한 접근법으로 여겨지고 있다. 그러나 전사조절유전자의 과발현에 의해 나쁜 농업형질의 유도 같은 문제점도 해결해야 한다.

• Current Research on Agriculture and Life Sciences
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• 제24권
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• pp.29-35
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• 2006

본 연구에서는 갈근 및 그의 주 이소플라본인 puerarin의 활성을 세포 수준에서 분석하였다. 먼저 갈근에 함유된 이소플라본의 양을 분석한 결과, puerarin이 총 이소플라본의 90 % 차지하였다. 다음으로는 puerarin의 항당뇨 활성을 검정한 결과 먼저 탄수화물 및 지방소화효소 저해활성에 대해서는 거의 미비한 것으로 나타났으나 인슐린 감수성 및 지방세포의 분화의 유도에 대해서는 농도 의존적으로 작용하는 것으로 관찰되었다. 따라서 puerarin은 지방조직내로 포도당의 흡수를 촉진함으로서 항당뇨 효능을 발휘하는 것으로 추정된다.

• Biomolecules & Therapeutics
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• 제15권1호
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• pp.34-39
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• 2007

Alzheimer's disease (AD) is an abnormal accumulation of the ${\beta}$-amyloid protein $(A{\beta})$ in specific brain region. It has been speculated that disturbance in cholesterol homeostasis may contribute to the etiology of AD by increasing $A{\beta}$ generation. However, conclusive evidence and possible mechanism has not been reported. In the present study, we demonstrated that rabbits treated with 0.5% cholesterol for 16 weeks increased serum total cholesterol, triacylglycerol, and low-density lipoprotein levels. $A{\beta}$ levels is higher in the hippocampus of brain in cholesterol dieted rabbits than that of normal diet rabbis. Expression and activities of ${\beta}-$ and ${\gamma}-$ secretases, the enzymes that cleave ${\beta}$-amyloid precursor protein to generate $A{\beta}$, were also increased in hippocampus of high cholesterol dieted rabbit than those of normal dieted rabbits. Our results suggest that high cholesterol diet may be associated with increased $A{\beta}$ accumulation in the brain of rabbits, and suggest that high cholesterol diet may be causal factor in the development or progression of AD.

• The Korean Journal of Physiology and Pharmacology
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• 제17권1호
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• pp.43-50
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• 2013

Palmitic acid (PAM), one of the most common saturated fatty acid (SFA) in animals and plants, has been shown to induce apoptosis in exocrine pancreatic AR42J cells. In this study, we investigated cellular mechanisms underlying protective effects of oleic acid (OLA) against the lipotoxic actions of PAM in AR42J cells. Exposure of cells to long-chain SFA induced apoptotic cell death determined by MTT cell viability assay and Hoechst staining. Co-treatment of OLA with PAM markedly protected cells against PAM-induced apoptosis. OLA significantly attenuated the PAM-induced increase in the levels of pro-apoptotic Bak protein, cleaved forms of apoptotic proteins (caspase-3, PARP). On the contrary, OLA restored the decreased levels of anti-apoptotic Bcl-2 family proteins (Bcl-2, Bcl-xL, and Mcl-1) in PAM-treated cells. OLA also induced up-regulation of the mRNA expression of Dgat2 and Cpt1 genes which are involved in triacylglycerol (TAG) synthesis and mitochondrial ${\beta}$-oxidation, respectively. Intracellular TAG accumulation was increased by OLA supplementation in accordance with enhanced expression of Dgat2 gene. These results indicate that restoration of anti-apoptotic/pro-apop-totic protein balance from apoptosis toward cell survival is involved in the cytoprotective effects of OLA against PAM-induced apoptosis in pancreatic AR42J cells. In addition, OLA-induced increase in TAG accumulation and up-regulation of Dgat2 and Cpt1 gene expressions may be possibly associated in part with the ability of OLA to protect cells from deleterious actions of PAM.

• Asian-Australasian Journal of Animal Sciences
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• 제27권3호
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• pp.414-421
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• 2014

This study was conducted to determine the effects of saturated long-chain fatty acids (LCFA) on cell proliferation and triacylglycerol (TAG) content, as well as mRNA expression of ${\alpha}s1$-casein (CSN1S1) and genes associated with lipid and protein synthesis in bovine mammary epithelial cells (BMECs). Primary cells were isolated from the mammary glands of Holstein dairy cows, and were passaged twice. Then cells were cultured with different levels of palmitate or stearate (0, 200, 300, 400, 500, and 600 ${\mu}M$) for 48 h and fetal bovine serum in the culture solution was replaced with fatty acid-free BSA (1 g/L). The results showed that cell proliferation tended to be increased quadratically with increasing addition of stearate. Treatments with palmitate or stearate induced an increase in TAG contents at 0 to 600 ${\mu}M$ in a concentration-dependent manner, and the addition of 600 ${\mu}M$ was less effective in improving TAG accumulation. The expression of acetyl-coenzyme A carboxylase alpha, fatty acid synthase and fatty acid-binding protein 3 was inhibited when palmitate or stearate were added in culture medium, whereas cluster of differentiation 36 and CSN1S1 mRNA abundance was increased in a concentration-dependent manner. The mRNA expressions of peroxisome proliferator-activated receptor gamma, mammalian target of rapamycin and signal transducer and activator of transcription 5 with palmitate or stearate had no significant differences relative to the control. These results implied that certain concentrations of saturated LCFA could stimulate cell proliferation and the accumulation of TAG, whereas a reduction may occur with the addition of an overdose of saturated LCFA. Saturated LCFA could up-regulate CSN1S1 mRNA abundance, but further studies are necessary to elucidate the mechanism for regulating milk fat and protein synthesis.

• BMB Reports
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• 제46권12호
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• pp.575-581
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• 2013

Lipid droplet (LD) is a cellular organelle that stores neutral lipids as a source of energy and carbon. However, recent research has emerged that the organelle is involved in lipid synthesis, transportation, and metabolism, as well as mediating cellular protein storage and degradation. With the exception of multi-cellular organisms, some unicellular microorganisms have been observed to contain LDs. The organelle has been isolated and characterized from numerous organisms. Triacylglycerol (TAG) accumulation in LDs can be in excess of 50% of the dry weight in some microorganisms, and a maximum of 87% in some instances. These microorganisms include eukaryotes such as yeast and green algae as well as prokaryotes such as bacteria. Some organisms obtain carbon from $CO_2$ via photosynthesis, while the majority utilizes carbon from various types of biomass. Therefore, high TAG content generated by utilizing waste or cheap biomass, coupled with an efficient conversion rate, present these organisms as bio-tech 'factories' to produce biodiesel. This review summarizes LD research in these organisms and provides useful information for further LD biological research and microorganism biodiesel development.

• Journal of Preventive Medicine and Public Health
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• 제46권sup1호
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• pp.3-11
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• 2013

Over the last two decades, significant research attention has been given to the acute effect of a single bout of exercise on postprandial lipaemia. A large body of evidence supports the notion that an acute bout of aerobic exercise can reduce postprandial triacylglycerol (TAG) concentrations. However, this effect is short-lived emphasising the important role of regular physical activity for lowering TAG concentrations through an active lifestyle. In 1995, the concept of accumulating physical activity was introduced in expert recommendations with the advice that activity can be performed in several short bouts throughout the day with a minimum duration of 10 minutes per activity bout. Although the concept of accumulation has been widely publicised, there is still limited scientific evidence to support it but several studies have investigated the effects of accumulated activity on health-related outcomes to support the recommendations in physical activity guidelines. One area, which is the focus of this review, is the effect of accumulating exercise on postprandial lipaemia. We propose that accumulating exercise will provide additional physical activity options for lowering postprandial TAG concentrations relevant to individuals with limited time or exercise capacity to engage in more structured forms of exercise, or longer bouts of physical activity. The benefits of accumulated physical activity might translate to a reduced risk of cardiovascular disease in the long-term.