• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.637-647
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• 2015

In this study, we attempted to understand signaling pathways behind lipid biosynthesis by employing a chemical genetics approach based on small molecule inhibitors. Specific signaling inhibitors of MAP kinase or modulators of cAMP signaling were selected to evaluate the functional roles of each of the key signaling pathways in three different microalgal species: Chlamydomonas reinhardtii, Chlorella vulgaris, and Haematococcus pluvialis. Our results clearly indicate that cAMP signaling pathways are indeed positively associated with microalgal lipid biosynthesis. In contrast, MAP kinase pathways in three microalgal species are all negatively implicated in both lipid and carotenoid biosynthesis.

• Preventive Nutrition and Food Science
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• v.20 no.1
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• pp.43-51
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• 2015

${\varepsilon}$-Polylysine (EPL) is used as a natural preservative in food. However, few studies have been conducted to assess the beneficial functions of dietary EPL. The purpose of this study was to elucidate the mechanism underlying the inhibition of neutral and acidic sterol absorption and hepatic enzyme activity-related fatty acid biosynthesis following EPL intake. EPL digest prepared using an in vitro digestion model had lower lipase activity and micellar lipid solubility and higher bile acid binding capacity than casein digest. Male Wistar rats were fed an AIN-93G diet containing 1% (wt/wt) EPL or L-lysine. After 4 weeks of feeding these diets, the marked decrease in serum and liver triacylglycerol contents by the EPL diet was partly attributed to increased fecal fatty acid excretion. The activities of hepatic acetyl-coenzyme A carboxylase and glucose-6-phosphate dehydrogenase, which are key enzymes of fatty acid biosynthesis, were enhanced in rats fed EPL diet. The increased fatty acid biosynthesis activity due to dietary EPL may be prevented by the enhancement of fecal fatty acid excretion. The hypocholesterolemic effect of EPL was mediated by increased fecal neutral and acidic sterol excretions due to the EPL digest suppressing micellar lipid solubility and high bile acid binding capacity. These results show that dietary EPL has beneficial effects that could help prevent lifestyle-related diseases such as hyperlipidemia and atherosclerosis.

• Journal of Plant Biology
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• v.39 no.3
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• pp.189-195
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• 1996

The major cuticular components have been shown to be synthesized in the epidermis. Therefore, cloning of epidermis-specific genes could yield information to be used to isolate and characterize the enzymes involved in the cuticle biosynthesis. A subtractive cDNA library was prepared from Senecio odorus in which epidermis-specific cDNAs were enriched. Differential screening of the library using epidermal and non-epidermal probes revealed two cDNAs. One of them designated epi425 was identified, based on the sequence homology, as a member of a new class in the LTP gene family and the other clone designated epi23 as a gene encoding an aldehyde decarbonylase. Northern blot analyses showed that epi425 and epi23 cDNAs hybridized with a transcript of about 600 and 2, 100 nucleotides, respectively, from the epidermis but not from the non-epidermal tissues. Further characterization of these clones will provide more information on the mechanism of the cuticle biosynthesis.

• Journal of the East Asian Society of Dietary Life
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• v.6 no.1
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• pp.51-58
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• 1996

The effects of allylisothiocyanate on the biosynthesis of various fungus metabolites such as sterigmatocystin, lipid, protein, citrate RNA and AMP from the culture of Aspergillus Parasiticus R-716 were investigated. The content of sterigmatocystin, the precursor of aflatoxin, was lower in the culture added with 50ppm allylisothicoyanate after 48 hours, however was rather higher after 144 hours compared to that of the control. The addition of allylisothiocyanate resulted in the increase of lipid, protein, RNA in mycelium and the content of citrate in the media, but the amount of AMP was low.

• Journal of Plant Biology
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• v.33 no.1
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• pp.49-54
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• 1990

Chlorella cells were cultured with M4N media treated with glucose (5 mM) sucrose (10 mM) and raffinose (30 mM). Phospholipids and their fatty acid compositions were analyzed in the chloroplast isolated from cultured Chlorella cells. Growth rate was prominently raised in the treatment with raffinose. Glucose was the most excellent carbon source in the biosynthesis of total lipid, phosphatidylcholine(PC), phosphatidylethanolamine(PE), phosphatidylinositol(PI) of the chloroplast. Also, the major fatty acids were palmitic, linoleic and linolenic acid during the biosynthesis of phospholipid in the control and in the treatment with carbon sources.

• The Plant Pathology Journal
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• v.22 no.3
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• pp.203-210
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• 2006

Fumonisins are a group of mycotoxins produced by a pathogen Fusarium verticillioides in infected maize kernels. Consumption of fumonisin-contaminated maize has been implicated in a number of animal and human illnesses, including esophageal cancer and neural tube defects. Since the initial discovery, chemistry, toxicology, and biology of fumonisins as well as the maize-Fusarium pathosystem have been extensively studied. Furthermore, in the past decade, significant progress has been made in terms of understanding the molecular biology of toxin biosynthetic genes. However, there is a critical gap in our understanding of the regulatory mechanisms involved in fumonisin biosynthesis. Here, we review and discuss our current knowledge about the molecular mechanisms by which fumonisin biosynthesis is regulated in F. verticillioides. In addition, we discuss the impact of maize kernel environment, particularly sugar and lipid molecules, on fumonisin biosynthesis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.5
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• pp.638-643
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• 2005

This study was peformed to investigate the effect of dietary iron and exercise on heme biosynthesis and lipid metabolism of rats. Rats were divided into 4 groups according to dietary iron supplement (Fe-,5 ppm vs. Fe+, 50 ppm) and exercise status (control us exercise). The experiment continued for 8 weeks. Regular treadmill exercise ($6^{\circ}$, 28 m/min, 30 min duration, 5 days/week) was given to exercise groups. The aminolevulinate dehydrase activity of red blood cell, the marker of heme biosynthesis, was significantly increased in the exercise group. Regular aerobic exercise reduced body weight and epidydimal fat pad gain. Regular exercise also significantly decreased the plasma triglyceride, cholesterol and HDL-cholesterol of the rats. Meanwhile, the iron deficiency decreased the hematocrit and hemoglobin concentration and increased the accumulation of liver cholesterol.

• The Korean Journal of Mycology
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• v.22 no.1
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• pp.8-30
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• 1994

The synthesis of phospholipids and the composition of fatty acids were analyzed in the fungal cells of Aspergillus phoenicis, Rhizopus acidus and Candida albicans treated with carbon sources (glucose, sucrose, raffinose) during the culture. Growth ratios were predominantly in Aspergillus and Candida treated with sucrose and those in Rhizopus treated with glucose. The synthesis of total lipids were accelerated in Aspergillus and Rhizopus with glucose and the contents of total lipid was increased in Candida with raffinose. The glucose treatment increased Phosphatidylinositol(PI) content by 73.7% for Aspergillus and Phosphatidylcholine(PC) content by 292% for Rhizopus. In sucrose treatment the synthesis of PI was accelerated 112% for Aspergillus and that of PC was increased 77.7% for Rhizopus and 71.8% for Candida. In raffinose treatment, the content of PC was increased 79.5% for Aspergillus, the biosynthesis of Phosphatidylethanolamine(PE) was inhanced 50.9% for Rhizopus and 49.1% for Candida. In Aspergillus and Candida, oleic acid and linoleic acid were major fatty acids for biosynthesis of PC and PE when the three carbon sources were treated. The major fatty acids for biosynthesis of phospholipid was palmitic acid and linoleic acid in Aspergillus, palmitic acid in Rhizopus and oleic acid in Candida. Palmitic acid was one of major fatty acids utilized for the biosynthesis of phospholipid(PC, PE, PI) in the fungal cells treated with carbohydrates.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.1
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• pp.19-24
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• 2004

To illuminate the physiological response to salinity, barnyard grass (Echinochloa hispidula) was germinated with high concentration of NaCl and KCL. Duration and promptness of seed germination were observed. Under salt stress, lipid peroxidation and polyamine biosynthesis were also analyzed. It appeared that high salt treatments per se did not provoke an inhibition of germination although the process of germination was significantly delayed. In context of lipid peroxidation and polyamine biosynthesis, we would imply that barnyard grass is tolerant to salinity. The increase in lipid peroxidation and putrescine content was prolonged only for 1 day after saline treatment. It could be concluded that these early acciimulation of putrescine and production of lipid peroxide seems to be associated with salt tolerance in the short-term. The physiological interest of these responses was discussed.

• KSBB Journal
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• v.25 no.6
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• pp.553-558
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• 2010

Increasing demands on fossil fuel have led to the unprecedented attraction to microalgal biofuel as an alternative energy. In this study, we investigated growth and lipid productions of microalga Nannochloris oculata under various carbon dioxide or nitrogen source concentrations and irradiance conditions. Biomass production of N. oculata was highest under 2% $CO_2$ with 0.3 flow rate (vvm). In addition, biomass productivities were proportional to the concentration of nitrogen source, whereas lipid biosynthesis was suppressed under higher nitrogen concentration (up to 50 mg/L). High irradiation ($160{\sim}180\;{\mu}mol/m^2{\cdot}s$) enhanced growth rate and lipid production of N. oculata.