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You searched for subject:(ZapA). Showing records 1 – 3 of 3 total matches.

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1. Buss, Jackson. BACTERIAL CELL DIVISION IN-SIGHT: A SUPER-RESOLUTION STUDY OF THE ESCHERICHIA COLI DIVISOME.

Degree: 2013, Johns Hopkins University

The polymerization of FtsZ into an annular structure (Z-ring) at midcell is the first recognized step in E. coli cell division, and is required for the recruitment of the remaining essential division proteins. Further studies suggest that the Z-ring itself may provide the force that drives constriction. Despite its importance, the in-vivo structure of the Z-ring remains unknown. Given the small size of bacteria, visualizing a cytoplasmic structure within an intact cell is technically challenging. Conventional fluorescence microscopy lacks the resolution needed for molecular insight, while electron microscopy fails to unambiguously identify subcellular structures in whole bacteria. To circumvent these challenges, we applied a single molecule-based super-resolution imaging technique, photoactivated localization microscopy (PALM), and determined the in-vivo structure of the Z-ring with a resolution of ~30nm. We found that in contrast to the homogenous, ring-like structure expected from previous studies, the Z-ring adopted a heterogeneous configuration with dimensions indicative of a loose, multi-layered protofilament arrangement. To further investigate the structural composition of the Z-ring, we determined the effect of two FtsZ-associated proteins, ZapA and ZapB, on the assembly dynamics and structure of the Z-ring. In cells deleted of zapA or zapB, we observed abnormal septa and highly dynamic FtsZ structures that resolve into disordered arrangements of FtsZ clusters via PALM. Quantitative analyses found these clusters were larger and contained more molecules than a single FtsZ protofilament, and likely represented a distinct polymeric species that is inherent to the assembly pathway of the Z-ring. Our results suggest that ZapA/B function to promote the alignment of FtsZ clusters into a ring-like arrangement and further propose that the FtsZ cluster, not the protofilament, is the basic structural unit of the Z-ring. Complimentary studies employing a variety of two-color and three-dimensional high-resolution imaging methods were applied to elucidate the spatial arrangement of FtsZ, ZapA and ZapB. Our results are consistent with a layered model whereby ZapB forms a stable, cytoplasmic raft upon which clusters of FtsZ protofilaments are anchored through ZapA. Advisors/Committee Members: Xiao, Jie (advisor).

Subjects/Keywords: FtsZ-ring; ZapA; ZapB; division

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Buss, J. (2013). BACTERIAL CELL DIVISION IN-SIGHT: A SUPER-RESOLUTION STUDY OF THE ESCHERICHIA COLI DIVISOME. (Thesis). Johns Hopkins University. Retrieved from http://jhir.library.jhu.edu/handle/1774.2/37021

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Buss, Jackson. “BACTERIAL CELL DIVISION IN-SIGHT: A SUPER-RESOLUTION STUDY OF THE ESCHERICHIA COLI DIVISOME.” 2013. Thesis, Johns Hopkins University. Accessed May 20, 2018. http://jhir.library.jhu.edu/handle/1774.2/37021.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Buss, Jackson. “BACTERIAL CELL DIVISION IN-SIGHT: A SUPER-RESOLUTION STUDY OF THE ESCHERICHIA COLI DIVISOME.” 2013. Web. 20 May 2018.

Vancouver:

Buss J. BACTERIAL CELL DIVISION IN-SIGHT: A SUPER-RESOLUTION STUDY OF THE ESCHERICHIA COLI DIVISOME. [Internet] [Thesis]. Johns Hopkins University; 2013. [cited 2018 May 20]. Available from: http://jhir.library.jhu.edu/handle/1774.2/37021.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Buss J. BACTERIAL CELL DIVISION IN-SIGHT: A SUPER-RESOLUTION STUDY OF THE ESCHERICHIA COLI DIVISOME. [Thesis]. Johns Hopkins University; 2013. Available from: http://jhir.library.jhu.edu/handle/1774.2/37021

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Bisson Filho, Alexandre Wilson. Estudo genético da interação entre FtsZ e o modulador de divisão ZapA em Bacillus subtilis.

Degree: Mestrado, Bioquímica, 2009, University of São Paulo

A citocinese bacteriana é controlada por diversas proteínas que se agrupam em um complexo chamado divisomo. O cerne do divisomo é constituído por FtsZ, uma proteína homóloga à tubulina eucariótica, que se auto-associa formando uma estrutura chamada anel Z. O anel Z serve como arcabouço e recruta diversas outras proteínas componentes do divisomo para o sítio onde o septo será sintetizado na célula. A formação do anel Z é modulada por proteínas que se ligam diretamente a FtsZ e regulam a sua auto-associação, tanto induzindo como inibindo a sua polimerização. Apesar de muitos destes moduladores de FtsZ já serem conhecidos, muito pouco se sabe sobre o mecanismo pelo qual eles controlam a estruturação do anel Z in vivo. O objetivo do presente trabalho foi estudar a interação entre FtsZ e um modulador de divisão, a proteína ZapA, da bactéria gram-positiva Bacillus subtilis. Para isso construímos uma biblioteca de mutantes de ftsZ por \"Error Prone PCR\", com aproximadamente 1 substituição por cópia de ftsZ e contendo um total de 1x105 clones. A partir dessa biblioteca, utilizamos duas triagens genéticas para identificar mutantes incapazes de interagir com ZapA. Na primeira estratégia, selecionamos 12 mutantes de FtsZ resistentes à superexpressão de uma forma tóxica de ZapA, que bloqueia a divisão, causando filamentação e morte das células. Surpreendentemente, apesar destes mutantes serem insensíveis ao efeito de ZapA, ensaios citológicos mostraram que nenhum deles perdeu a interação com ZapA. Como as mutações foram mapeadas nas vizinhanças do sítio catalítico e de polimerização de FtsZ, e como a maioria delas confere resistência cruzada aos efeitos de outros moduladores de FtsZ, suspeitamos que elas afetassem a estabilidade do polímero de FtsZ e, consequentemente, o comportamento do anel Z. Essas suspeitas foram confirmadas em ensaios de FRAP e cálculos de proporção de FtsZ no anel Z, indicando que os mutantes formam um anel Z mais estável que o normal. Como não obtivemos mutantes que perderam a interação com ZapA na primeira triagem, aplicamos a biblioteca em uma segunda estratégia de triagem genética, procurando um mutante de FtsZ que voltasse a interagir com um mutante de ZapA que não se liga mais a FtsZ (ZapAN62A). Esta estratégia de ganho de função identificou um candidato, FtsZE91V , que, tanto por critérios genéticos como citológicos, voltou a interagir com ZapAN62A. Apesar do mutante FtsZE91V mostrar-se capaz de restaurar a interação com ZapAN62A, ele não afetou a interação com ZapA selvagem, segundo nossos ensaios de microscopia de fluorescência e viabilidade. O mutante FtsZE91V, mapeia na hélice H3 de FtsZ. Esta hélice está exposta na superfície de FtsZ (compõe um dos lados da molécula de FtsZ) de uma maneira compatível com a idéia de que ela seria importante para interações laterais entre polímeros de FtsZ. Nossos resultados apontam, portanto, que a hélice H3 deve ser o sítio de interação para ZapA em FtsZ.

The bacterial cytokinesis is ruled by a number of proteins that constitute the divisome complex. FtsZ,…

Advisors/Committee Members: Gueiros Filho, Frederico José.

Subjects/Keywords: Bacillus subtilis; Bacillus subtilis; Anel Z; Biologia molecular; Divisão celular; Divisome; Divisomo; FtsZ; FtsZ; Genética bioquímica; Moduladores; Modulators; Molecular biology; Z ring; ZapA; ZapA

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Bisson Filho, A. W. (2009). Estudo genético da interação entre FtsZ e o modulador de divisão ZapA em Bacillus subtilis. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/46/46131/tde-03082009-090556/ ;

Chicago Manual of Style (16th Edition):

Bisson Filho, Alexandre Wilson. “Estudo genético da interação entre FtsZ e o modulador de divisão ZapA em Bacillus subtilis.” 2009. Masters Thesis, University of São Paulo. Accessed May 20, 2018. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-03082009-090556/ ;.

MLA Handbook (7th Edition):

Bisson Filho, Alexandre Wilson. “Estudo genético da interação entre FtsZ e o modulador de divisão ZapA em Bacillus subtilis.” 2009. Web. 20 May 2018.

Vancouver:

Bisson Filho AW. Estudo genético da interação entre FtsZ e o modulador de divisão ZapA em Bacillus subtilis. [Internet] [Masters thesis]. University of São Paulo; 2009. [cited 2018 May 20]. Available from: http://www.teses.usp.br/teses/disponiveis/46/46131/tde-03082009-090556/ ;.

Council of Science Editors:

Bisson Filho AW. Estudo genético da interação entre FtsZ e o modulador de divisão ZapA em Bacillus subtilis. [Masters Thesis]. University of São Paulo; 2009. Available from: http://www.teses.usp.br/teses/disponiveis/46/46131/tde-03082009-090556/ ;


Virginia Tech

3. Clement, Ella Chow. Design and Syntheses of Potential Drugs Based on GABA(A) Receptor Pharmacophores.

Degree: Chemistry, 2005, Virginia Tech

Design and Syntheses of Potential Drugs Based on GABAA Receptor Pharmocophores Ella Chow Clement ABSTRACT Numerous previous studies of GABAAR ligands have suggested that GABAAR agonists must be zwitterionic and feature an intercharge separation similar to that of GABA (approx. 4.7-6.0 Ã ). We have demonstrated that monomeric, homodimeric and heterodimeric non-zwitterionic GABA amides are partial, full, or superagonists at the murine GABAA receptor (GABAAR). The agonism of these GABA amides is comparable to that of THIP, as shown by in vitro assay results. The assay data indicate that the agonism of GABA amides is tether length-dependent. Optimum agonism is achieved with a tether length of four methylenes in GABA amide dimers and in GABA amides bearing pendant amide or amino groups. We have further investigated the structure-activity relationship for GABA amides on the GABAAR by performing structural modifications to both the superagonist 2c and the agonist 6c. Synergism and [3H]muscimol binding experiments show that 2c binds to the same sites as GABA. Structural modification of 2c demonstrated that partial rigidification of the tether eliminated agonism and caused ligands to behave as weak competitive antagonists. We have also investigated the agonism of four ZAPA derivatives in 36Cl- uptake functional assay. Two of them are found to be as potent as GABA. In our studies of 1,4-benzodiazepines, our goal was to synthesize three different subtypes of quaternary 1,4-benzodiazepines by use of the memory of chirality (MOC) strategy. Disappointingly, most of the deprotonation/alkylations failed, due to various reasons. The failure of the reactions of (S)-alanine-derived tetrahydro-1,4-benzodiazepin-3-ones was probably due to either the unexpected side reactions or the steric hindrance of enolate alkylation. In the case of tetrahydro-1,4-benzodiazepin-2-ones, computational studies suggested that steric hindrance by both the benzo ring and N4-allyl group might retard deprotonation at C3 by bulky bases like KHMDS or LDA. Finally, (S)-serine-derived 1,4-benzodiazepin-2-ones and their elimination products (ï ¡-methylene benzodiazepines) were prepared. These proved unreactive towards deprotonation/alkylations and conjugate additions, respectively. The low reactivity of the ï ¡-methylene benzodiazepines towards nucleophiles was attributed to highly delocalized LUMOs that failed to direct nucleophiles to the ï ¢-carbons. Advisors/Committee Members: Carlier, Paul R. (committeechair), Kingston, David G. I. (committee member), Tanko, James M. (committee member), Bloomquist, Jeffrey R. (committee member), Gandour, Richard D. (committee member).

Subjects/Keywords: Memory of Chirality; ZAPA; PEG; [3H]Muscimol binding; 36Cl- Flux assay; Antagonists; Non-zwitterionic GABA amide homodimers and heterod; Superagonist; Partial/full agonists; GABA(A) receptor

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Clement, E. C. (2005). Design and Syntheses of Potential Drugs Based on GABA(A) Receptor Pharmacophores. (Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/28271

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Clement, Ella Chow. “Design and Syntheses of Potential Drugs Based on GABA(A) Receptor Pharmacophores.” 2005. Thesis, Virginia Tech. Accessed May 20, 2018. http://hdl.handle.net/10919/28271.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Clement, Ella Chow. “Design and Syntheses of Potential Drugs Based on GABA(A) Receptor Pharmacophores.” 2005. Web. 20 May 2018.

Vancouver:

Clement EC. Design and Syntheses of Potential Drugs Based on GABA(A) Receptor Pharmacophores. [Internet] [Thesis]. Virginia Tech; 2005. [cited 2018 May 20]. Available from: http://hdl.handle.net/10919/28271.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Clement EC. Design and Syntheses of Potential Drugs Based on GABA(A) Receptor Pharmacophores. [Thesis]. Virginia Tech; 2005. Available from: http://hdl.handle.net/10919/28271

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.