Production of Lysine by Lactobacilli or Aspergillus Ficuum

In the animal feed industries, there is a global need for adding certain nutritional ingredients to augment deficits usually associated with plant-based materials. As a result, the industrial practices require direct addition of ingredients such as amino acids and vitamins. One of the key ingredients in this context is lysine. Alternately, the same goal can be achieved indirectly through in situ co-culturing of microorgan-isms. The focus of this thesis was genetic improvement of bacterial and /or fungal mutants, which could over-produce lysine. The accumulation of free lysine during microbial growth serves this end based on de-regulation of the lysine biosynthetic pathway. Microorganisms used in this thesis were nine species of lactobacilli and Aspergillus ficuum. Having in mind the highly complex nutritional requirements of lacto-bacilli, the assessment of possible lysine auxotrophy was performed. No lysine auxotrophs were found and the choice of Lactobacillus plantarum as the working species among nine others was based on its higher growth rate in minimal medium. Selection of mutants that overproduced lysine was carried out in the minimal medium supplemented with the following lysine analogs: S-aminoethyl-L-cysteine (AEC), DL-aspartic acid-ƒÒ-hydroxamate (DL-ASP), ƒÒ -fluoropyruvic-acid (FPA), L-lysine hydroxamate (LHX) and diaminopimelic acid (DAP). In L. plantarum, LHX was shown to be the most potent inhibitor; although, the bacterium demonstrated high resistance to all the analogs tested. The inhibition by LHX was obtained only after significant alteration of the minimal medium M3. Furthermore, the mutant # 34, resistant to 2 mM of LHX, secreted only 4.52 £gM of lysine in M3. To address the question of low lysine yield obtained by L. plantarum, thorough study of the regulation of aspartokinase (AK) was performed. It was found that AK exists as four isozymes, threonine sensitive, methionine sensitive and two lysine sensitive isozymes. Activity differed with respect to the growth stage of L. plantarum. Beside lysine, threonine and methionine have influenced the repression of AK isozymes, which suggested that effective lysine over-production could be obtained only if AK is simultaneously resistant to threonine and methionine analogs. In the case of A. ficuum, mutant #5-10 secreted 29.25 £gM of lysine in the minimal medium, which was approximately 30 % higher than that of the wild type. DL-ASP was found as the most potent inhibitor only after the conidia were soaked for 8 h in 0.03 % Tween 80. Ammonium phosphate as a nitrogen source enhanced lysine secretion in A. ficuum compared to five other nitrogen sources tested

Polarimetric Incoherent Target Decomposition by Means of Independent Component Analysis

International audienceThis paper presents an alternative approach for polarimetric incoherent target decomposition dedicated to the analysis of very-high resolution POLSAR images. Given the non-Gaussian nature of the heterogeneous POLSAR clutter due to the increase of spatial resolution, the conventional methods based on the eigenvector target decomposition can ensure uncorrelation of the derived backscattering components at most. By introducing the Independent Component Analysis (ICA) in lieu of the eigenvector decomposition, our method is rather deriving statistically independent components. The adopted algorithm - FastICA, uses the non-Gaussianity of the components as the criterion for their independence. Considering the eigenvector decomposition as being analogues to the Principal Component Analysis (PCA), we propose the generalization of the ICTD methods to the level of the Blind Source Separation (BSS) techniques (comprising both PCA and ICA). The proposed method preserves the invariance properties of the conventional ones, appearing to be robust both with respect to the rotation around the line of sight and to the change of the polarization basis. The efficiency of the method is demonstrated comparatively, using POLSAR Ramses X-band and ALOS L-band data sets. The main differences with respect to the conventional methods are mostly found in the behaviour of the second most dominant component, which is not necessarily orthogonal to the first one. The potential of retrieving non-orthogonal mechanisms is moreover demonstrated using synthetic data. On expense of a negligible entropy increase, the proposed method is capable of retrieving the edge diffraction of an elementary trihedral by recognizing dipole as the second component

Pedagogiskt ledarskap i förskolan : Förskollärares uppfattningar om eget pedagogiskt ledarskap

Syftet med denna avhandling är att i en förskolekontext och ur ett lärarperspektiv undersöka pedagogiskt ledarskap. Därmed har denna forskningsfråga formulerats: Vilka uppfattningar har lärare inom småbarnspedagogik om pedagogiskt ledarskap i förskolan? Avhandlingen bygger på en fenomenografisk ansats. Informanterna är nio lärare inom småbarnspedagogik från olika förskoleavdelningar inom Österbotten. Datainsamlingsmetoden är halvstrukturerade intervjuer och enkäter med öppna frågor. Datamaterialet analyseras utifrån en fenomenografisk sjustegsmodell för analys av data. I resultatet framkommer förskollärarnas olika uppfattningar om eget pedagogiskt ledarskap. Svaren har därmed kategoriserats under A. Pedagogiskt ledarskap är att leda barns utveckling, B. Pedagogiskt ledarskap är verksamhetsplanering utifrån mål och läroplanen och C. Pedagogiskt ledarskap är kollektivt. Lärarna anser att deras pedagogiska ledarskap i förskolan är ett komplext fenomen som är situationsbaserat. Denna komplexitet presenteras i resultatredovisningen

Poincare Sphere Representation Of Independent Scattering Sources: Application On Distributed Targets

International audienceThis paper introduces Independent Component Analysis (ICA) to the Incoherent Target Decomposition theory (ICDT) through the particular application - snow cover analysis. Given that the equivalence of the currently used eigenvalue decomposition and Principal Component Analysis (PCA) can be stated under certain constraints, the goal is to generalise ICDT in the context of Blind Source Separation (family of techniques comprising both PCA and ICA). This generalisation allows independent non-orthogonal backscattering mechanisms retrieval in case of non-Gaussian polarimetric clutter. The obtained independent target vectors are parametrized using the Target Scattering Vector Model (TSVM). The algorithm is applied on a distributed target - snow cover, and the obtained parameters are illustrated and appropriately interpreted using the Poincare sphere

The analysis of dimensional stability of 1x1 RIB Co and Co/LY knitwear

© 2018 Inst. Nat. Cercetare-Dezvoltare Text. Pielarie. All rights reserved. This paper analyzes the impact of knitwear's fiber composition, linear density and finishing of yarn used in the dimensional stability of the 1x1 RIB knitwear made on the same circular knitting machine. Dimensional stability of these samples was analysed by FAST 4 method. Different samples were compared across multiple indicators. The results show that the most stable dyed knitted fabric are made of cotton 96% and 4% of Lycra and of yarn with linear density 19.14 tex. Tightness factor's values in the dry relaxation stood at 17.90, in the wet 18.45, in total 18.73 and 18.59 in air conditioned terms. Knitwear with the highest values of dimensional instability are raw knitted fabric made of 100% CO, and yarn with linear density of 13.39 tex. Tightness factor's values in the dry relaxation stood at 12.16, in the wet 12.36, in total 13.26 and 13.35 in air conditioned terms