Amaral, A. L.

Belo, Isabel

Braga, Adelaide

Ferreira, Eugénio C.

Mesquita, D. P.

Universidade do Minho: RepositoriUM

238 MCM2015 • August23-28, 20 15 • Eger, Hungary The second approach is based on the separate detection of e lectron.dense markers at the top and the bottom side of ultrathin sections (3). Labels at the top side of ultrathin section are detected in backscattered electron imaging u..o;ing primary electrons with the energy around lkeV. Primary e lectrons with the energy between 15 and 30 keV are used for image recording of the same area in the STEM mode~ when transmitted electrons ar e detected. ln this case we can visualize labe ls on both sides of the ultrathin section together with its cell uJtra..'itructure. Using of both sides of sections for immunolabeling means doubling of the number of de· tected epitopes compared to commonly one.sided immunolabeling methods. This work was supported by the grant of Technology Agency of the Czech Republic (No. TEO llll20 118) and the Institutional Grant of Institute of Parasitology (no. AVOZ602205 18). Rder,.ences I. M. Vancova, M. Slouf, J. Langhans, E. Pawlova, J. Nebesarova. Microsc. Microanal. 17(:5), &lo-8 16, 20 11 2. M. 'Slouf, M. Hruby, Z. Bakaeva, H . Vlkova, J. Nebesarova,A. A . Philimonenko, P. Hozak. Colloids Surf B Biointerfaces, I 00, 205-208, 2012 3. P. Wandrol, M. Vancova, J. Nebesarova. Microsc. Microanal. 211l, S3, 126&-1267, 2014 0.141 EVALUATION OF DIMORPIDC YARROWIA LIPOLYTICA STRAINS GROWTH IN DLFFERENT CULTURE MEDIA BY QUANTITATIVE IMAGE ANALYSIS AntOnio Luis AmaraJl.l, Daniela Patricia Mesquita 1, Adelaide Braga 1, Lvabel Belo 1, Eugenio Campos Ferreira 1 1Centr;o de Engenharia Bio16gica, Universidadedo Minho, Campus de Gualtar, 4710-057 Braga. Portu.gaJ. e-mails: lpamaral@deb.uminho.pt; daniela@deb.uminho.pt; adelaidebragal@gmail.com; ibelo@deb.uminho.pt~ ecferreira@deb.uminho.pt ' lnstillllto Superior de Engenharia, lnstiruto Politocnico de Coimbra, Rua Pedro Nunes, Quinta da Nora'" 3030- 199, Coimbra, PortugaJ, e-mail: lpam.araJ@isec.pt Keywords: Y. lipolytica. quantitative in:t.age analysis, dimorphic growth Yarrowia lipolytico is a dimorphic ll!licroorganism capable of growing as a mixture of yeasts and short myceJial cells. However, under controlled conditions, ill may grow as a quasi·ho-mogelleous population of either yeast-like oells or hyphae [ I). The role of different factors in dimorphic tran..'iirion of Y. lipolytica has been previously described, namely carbon and nitrogen sources ( I), blood serum [2), citrate and medium pH (3) . This yeast has the ability to use hydrophobic substrates (n·a llkanes, oils, fats) in productio11 of lipa<;es and esterases, single ceiJ oil and in the treatment of wa..'itewater. as well as non-hydrophobic subtracts (sug· ars, alcohols and organic acids) (4). CelJ morphology has a strong impact in several activities of industrial interest revealed by this yeast. This wide morphology greatly affects fermentation performance. since it in· OraJ Presentations: LS - Multidisciplinary approaches in biology and medicine - AbsLrac.ts 239' duces rheological changes and consequently lead'i to mass and heat transfer alterations in the bioreactor. Hence, understanding cell morphology became an important key to enhance and optimize the p roductivity of the process. Quantitative image analysis (Q!A) procedures can provide valuable information about the biological processes, and allow for a monitoring tool to decide if a given action should be carried out in the system. However, to the authors' knowledge, QIA has never been applied for characterizing dimorphic growth of Y. lipolytica in different carbon sources. During the monitoring period, samples were collected for morphological characterizatioru using Q!A in bright-field microscopy. The yeasl,· t<>-hyphae d imorphic transition in Y. lipo·· lytica W29 and MTLY40-2P strains, were detem1ined over time. The growth of Y. lipolytica strains showed a differential dimorphic behaviour in response to the presence of hydrophobic (olive oil and castor oil) or hydrophilic (N· Acetyl g lucosamine (Gic) and glucose) carboru sources. Images at the end of each growth test are presented in Table I. It was verified by QIA that, for both strains, the presence of olive oil (01), Glc, and glucose in the culture media induced the transition from yeast to hypha form. Furtthennore, when castor o il (Co) was used as carbon source no morphological changes were observed. Table I. lm.ag.es obtained at tbe end o( eaoh test with the four carbon sources u.nd tor eacb strain ~udied, aft<r QIA (hyphae in red, )'<o15tS ins>'""") Cari>on s.ouroe. Glc Glucose. 01 Co Strain 240 MCM2015 · August 23-28,20 15 • Eger, Hungary In conclu..o;ion, it could be found that QIA can be used a.s a simple and accurate methodol· ogy to assess and characterize yeasts•to·hyphae d imorphic transition in near real time. The authors thank the Project REF.NORTE-07.0124-FEDER.000028 co-funded by the Pro-grama Operacional Regional do Norte (ON.2 - 0 Novo Norte, QREN, FEDER, '' BioEnv - Biotechnology and Bioengineering for a sustainable world", REF. NORTE-07-0 124-FED-ER-000048, co- funded by the Programa Operacional Regional do Norte (ON.2 - 0 Novo Norte, QREN, FEDER and FCT SFRH/BD/63701/2009, S FRH/BPD/82558/201 1 PhD and post-doctoral grant' to Adelaide Braga and Daniela Mesquita, respectively) for the financial support provided and FCT Strategic Project PEst-OEIEQBILA0023/20 13. References I. C. Rodriguez; A. Dominguez, "The growth characteristics ofSaccharomycopsis lipolyrica: morphology and induction of mycelium formation", Can. J. Microbiol., 30, 60~ 12, 1984 2. A. Dominguez, E. Fem1inan, C. Gaillardin, '"Yarrowia lipolyrica: an organism amenable to genetic manipulation as a mode] for anaJyzing dimorphism in fungi". Contrib Microbial., 5, 151-172, 2000 3. J. Ruiz-Herrera, R. Sentandreu, " Different effectors of dimorphism in Yarrowia lipolyri· ca", Arch. Microbiol., 178,477- 83,2002 4. J. M. Nicaud, "Yarrowia lipolyrica", Yeast, 29,409-418,2012 

Evaluation of dimorphic Yarrowia lipolytica strains growth in different culture media by quantitative image analysis

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