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Veeranagouda, Yaligara,Lee, Kyoung,Cho, Ah Ra,Cho, Kyungyun,Anderson, Erin M,Lam, Joseph S Published by Elsevier/North Holland on behalf of t 2011 FEMS microbiology letters Vol.315 No.1
<P>In the presence of vaporized p-cresol, Pseudomonas alkylphenolia KL28 forms specialized aerial structures (SAS). A transposon mutant of strain KL28 (C23) incapable of forming mature SAS was isolated. Genetic analysis of the C23 mutant revealed the transposon insertion in a gene (ssg) encoding a putative glycosyltransferase, which is homologous to the Pseudomonas aeruginosa PAO1 PA5001 gene. Deletion of ssg in KL28 caused the loss of lipopolysaccharide O antigen and altered the composition of the exopolysaccharide. Wild-type KL28 produced a fucose-, glucose- and mannose-rich exopolysaccharide, while the mutant exopolysaccharide completely lacked fucose and mannose, resulting in an exopolysaccharide with glucose as the major component. The mutant strain showed reduced surface spreading, pellicle and biofilm formation, probably due to the cumulative effect of lipopolysaccharide truncation and altered exopolysaccharide composition. Our results show that the ssg gene of KL28 is involved in both lipopolysaccharide and exopolysaccharide biosynthesis and thus plays an important role in cell surface properties and cell-cell interactions of P. alkylphenolia.</P>
Surface characterization and electrical behavior of polyaniline–polymannuronate nanocomposites
Basavaraja, C.,Veeranagouda, Y.,Lee, Kyoung,Pierson, R.,Huh, Do Sung Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of polymer science. Part B, Polymer physic Vol.47 No.1
<P>Conducting polyaniline-polymannuronate (PANI-PM) composites were synthesized via in situ deposition techniques. By dissolving different weight percentages of polymannuronate (PM) (5, 10, 15, and 25%), the oxidative polymerization of aniline was achieved through the use of ammonium persulfate as oxidant. Structural morphology, FT-IR, and X-ray diffraction (XRD) studies support a strong interaction between PANI and PM. The temperature-dependent DC conductivity of PANI-PM composites was studied within the range of 300 ≤ T ≤ 500 °K, presenting evidence for the transport properties of PANI-PM composites. Conductivity was analyzed through Mott's equation, which leveraged the variable range hopping model in three dimensions. Parameters such as density of states at the Fermi energy, hopping energy, and hopping distance were calculated. Based on the above factors, the synthesis of PANI-PM composites envisages the future development of biomimetic materials for the creation of a new bionanocomposite as a multicomponent and multifunctional material. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 36–45, 2009</P>
Ultramicrocells form by reductive division in macroscopic <i>Pseudomonas</i> aerial structures
Lee, Kyoung,Veeranagouda, Yaligara Blackwell Publishing Ltd 2009 Environmental microbiology Vol.11 No.5
<P>Summary</P><P>Bacterial aerial growth with reductive cellular division and morphological development has not been reported from single-cell bacteria. Here we show that within 1 month of incubation in vaporized <I>p</I>-cresol, <I>Pseudomonas</I> sp. KL28 form shiny, highly branched specialized aerial structures of millimetre-scale diameter. The developmental process displayed spatially and temporally distinct stages; an initial sphere stage was followed by ramification, which led to highly branched tip formation. In this morphogenesis process, the extracellular matrix (ECM) played an important role for maintaining the integrity of sectional populations and the boundaries between adjacent sectors. In addition, cellular division, lysis and migration within the aerial structures were also accompanied. During prolonged incubation, clusters of short-rod cells covered by an outer layer of thick ECM underwent reductive transformation and then replicative reductive division to form oval ultramicrocells of < 0.4 &mgr;m in diameter. In addition, the aerial structures protected these rather fragile cells from desiccation and served as a selection pressure for wrinkly, spreading cell variants. The formation of aerial structures is affected positively and negatively by a GacA regulator and RpoS, respectively, and is linked to other phenotypes. Our results demonstrate that <I>Pseudomonas</I> has an ecological adaptation to form mushroom-like aerial structures, which can be a tool for studying cell–cell interactions and bacterial development.</P>
The Study of DC Conductivity for Polyaniline-polymannuronate Nano Composites
허도성,Y. Veeranagouda,이경,R. Pierson, M. Revanasiddappa,바사바 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.12
Conducting polyaniline-polymannuronate (PANI-PM) composites have been prepared by in situ deposition technique by placing different wt.% of fine grade powder of polymannuronate (5, 10, 15, and 25%) during polymerization of polyaniline. The oxidative polymerization of aniline was carried by using ammonium persulfate as oxidant. Further the temperature-dependent DC conductivity of PANI-PM composites was studied within the range of 300 ≤ T ≤ 500 K. The conductivity data shows an evidence for the transport properties of PANI-PM composites. This study in turn supports the strong interaction of PANI with PM in the composites. Based on the DC conducting properties the composites signify the future development of new materials for the creation of new bio-nanocomposites that has a multi-component and multifunctional material.
Thermal and Electrochemical Properties of Polymannuronate-polyaniline Nanocomposites
Basavaraja, C.,Veeranagouda, Y.,Kim, Na-Ri,Jo, Eun-Ae,Lee, Kyoung,Huh, Do-Sung Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.5
New types of conducting polyaniline-polymannuronate (PANI-PM) composites were synthesized by in situ deposition techniques in an aqueous media. By dissolving different weight percentage of polymannuronate (PM) (5, 10, 15, and 25%), the oxidative polymerization of aniline was carried out using ammonium per sulfate as an oxidant. The obtained composites were studied for their thermal stability and electrochemical behavior. The thermal stability of PANI-PM composites is lower than PANI, which supports a strong interaction between PANI and PM. However, the composites show an appreciable electrochemical behavior. Based on these observation the PANI-PM composites can be explored in different fields such as electric devices, sensors, functional coatings, etc.