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Morita, T., Ishibashi, Y., Fukuoka, T., Imura, T., Sakai, H., Abe, M. and Kitamoto, D. (2009) Production of Glycolipid Biosurfactants, Mannosylerythritol Lipids, Using Sucrose by Fungal and Yeast Strains, and their Interfacial Properties. Bioscience, Biotechnology, and Biochemistry, 73, 2352-2355. http://dx.doi.org/10.1271/bbb.90439

has been cited by the following article:

• TITLE: Nitrogen Source Affects Glycolipid Production and Lipid Accumulation in the Phytopathogen Fungus Ustilago maydis

  AUTHORS: Ariana Zavala-Moreno, Roberto Arreguin-Espinosa, Juan Pablo Pardo, Lucero Romero-Aguilar, Guadalupe Guerra-Sánchez

  KEYWORDS: Nitrogen Starvation, Yeast Glycolipids, Lipid Droplets, Lipid Accumulation

  JOURNAL NAME: Advances in Microbiology, Vol.4 No.13, October 21, 2014

  ABSTRACT: When cultured in medium limited of nitrogen sources, the phytopathogen Ustilago maydis produces two amphipathic glycolipids: Ustilagic acid (UA) and Mannosylerythritol lipid (MEL), which in addition to the hydrophilic moiety, contain dior tri-hydroxylated C16 fatty acids (UA), or C8 and C16 saturated fatty acids (MEL). We compared the growth and morphology of cells in YPD and in minimum media containing glucose and nitrogen sources such as nitrate or urea and those deprived of nitrogen. Nitrogen-starved cells showed a dramatic accumulation of internal lipids identified as lipid droplets when stained with the hydrophobic probe BODIPY; these lipid droplets were enriched in unsaturated fatty acids. Fatty acids in YPD or medium containing nitrate as nitrogen source showed a combination of saturated/unsaturated lipids, but when urea was the nitrogen source, cells only contained saturated fatty acids. The glycolipid profiles produced in the presence or absence of nitrogen showed preferences towards the production of one kind of glycolipid: cells in media containing nitrate or urea produced different proportions of UA/MEL, but under nitrogen starvation cells contained only UA. The emulsification capacity of the glycolipids produced in media with or without nitrogen was similar (72% - 76%). HPLC of the glycolipids allowed the separation of fractions with different emulsifying characteristics. Our results indicate that U. maydis accumulates lipid droplets when deprived of nitrogen source and confirm that UA is not under nitrogen control, but rather that MEL and lipid droplets are produced and oppositely regulated by nitrogen.