Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 0880. Adviser: Nigel Goldenfeld. Includes bibliographical references (leaves 158-176) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--Brown University, 2008. / Vita. Advisor : Xingsheng Sean Ling. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:30:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-14Bitstream added on 2014-06-13T19:19:37Z : No. of bitstreams: 1 tosqui_p_dr_sjrp.pdf: 1146910 bytes, checksum: 6aba6f1c199f0bebfaeca2737005759b (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A influência de ânions sobre as características estruturais e funcionais de hemoglobinas (Hb) vem sendo alvo de pesquisas de nosso laboratório nos últimos anos. Estudos anteriores mostraram que a ligação preferencial de ânions como o Cl- e fosfatos orgânicos (2,3-DPG, IHP) entre outros à desoxi-Hb humana (HbA), modula o equilíbrio entre dois estados alostéricos desoxigenados possíveis, estados To e Tx, livre e complexado com ânions, respectivamente. Medidas funcionais utilizando o método de estresse osmótico, que determina o número de moléculas de água que se liga a superfície da Hb, acompanhando a oxigenação, mostraram que o estado To é um estado com hidratação e afinidade ao oxigênio intermediárias ao Tx e ao oxi-R. Assim, a oxigenação da Hb demanda um modelo considerando estes três estados, To, Tx e R, modulados pela presença de ânions em solução. O íon cloreto é um dos ânions de maior importância fisiológica. A presença de sítios específicos para sua ligação, bem como seu sistema de ligação para a Hb, contudo, são controversos. Evidências estruturais e funcionais apontaram os resíduos arginina 141 e 92 da cadeia alfa como possíveis sítios de ligação de cloreto à Hb. Para investigar essa hipótese, realizamos estudos funcionais variando atividade de água e pH (efeito Bohr), em função da presença de cloreto com hemoglobinas mutantes para essas posições. As hemoglobinas selecionadas foram Chesapeake (R92L), J-Cape Town (R92Q), desArg (141Δ) e Chesapeake desArg (R92L,141Δ). Aspectos estruturais dessas Hbs foram obtidos através de espectroscopia 1H RMN. Todas as Hbs estudadas apresentaram afinidade maior ao oxigênio quando comparadas à HbA, para todas as condições experimentais. Estudos de variação da atividade de água em função da concentração de cloreto mostraram que a única... / The influence of anions on structural and functional properties of hemoglobins (Hb) has been studied by our research group for the last few years. Former studies have shown that the preferential binding of anions, such as Cl and organic phosphates (2,3-DPG, IHP) among others to human deoxy-Hb (HbA), modulates the equilibrium between two possible deoxy states: To and Tx, free and complexed with anions respectively. Functional measurements using the osmotic stress method, which allows the determination of the number of water molecules that binds to the protein surface upon the change in protein conformation induced by oxygenation, showed that To state has intrinsic affinity and hydration intermediate of those of Tx and oxy-R . Hence, Hb oxygenation requires a three state model, considering To, Tx and R, modulated by the presence of anions in solution. Chloride is one of the most important physiological ions and the presence of specific binding sites of this anions is controversial. Structural and functional evidence have pointed to Arginines 141 and 92 as possible binding sites for chloride to Hb. To investigate this hypothesis, we have performed functional studies, changing the water activity and pH (Bohr effect), in function of chloride concentration with recombinants Hbs for these positions. The selected hemoglobins are Chesapeake (R92L), J-Cape Town (R92Q), desArg (141Δ) eandChesapeake desArg (R92L,141Δ). Structural features were obtained through 1H NMR spectroscopy. All Hbs studied have higher affinity than HbA for all experimental conditions. Water activity studies in function of chloride concentration showed that the only Hb that can be adjusted with the three state model is Hb desArg, whereas the other Hbs don’t present the Tx state, fact confirmed by the number of water molecules bound to each... (Complete abstract click electronic access below)

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Computational Biology and Molecular Biophysics." Includes bibliographical references.

<p> The cellular stress response (CSR) is one of the most highly conserved mechanisms among all organisms. Cellular stress can be defined as damage or the threat of damage to proteins, macromolecules and/or DNA. The response to damage can involve cell cycle regulation, protein chaperoning, DNA repair or, if macromolecular damage is too severe, apoptotic mechanisms can be initiated. This thesis details experiments that were designed to examine the cellular response to non-lethal environmental stressors at the protein level, using two fish species as study models. Two proteins that can cause cell cycle arrest and apoptosis mechanisms were examined. Expression of the CCAAT enhancer binding protein-delta (C/EBP-&delta;) was examined in the zebrafish, <i>Danio rerio,</i> exposed to acute, non-lethal hypoxic conditions. While C/EBP-&delta; was expressed constitutively in control individuals during all time points, exposure to hypoxic conditions did not have a consistent significant effect on C/EBP-&delta; expression (two-way ANOVA, P>0.05) in zebrafish white muscle tissue. In a second study, the expression of the growth arrest and DNA damage 45-alpha protein (gadd45-&alpha;), a mediator of cell cycle arrest and perhaps apoptosis was examined in heat-stressed liver tissue of an extremely cold-adapted Antarctic fish, <i>Trematomus bernacchii.</i> Gadd45-&alpha; levels were higher in fish exposure to 2&deg;C across all time points (one-way ANOVA; P&lt;0.05). The findings in these two studies expand our understanding of the CSR and how two genes that are involved in cell cycle regulation respond to acute, non-lethal environmental stress.</p>

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Computational Biology and Molecular Biophysics." Includes bibliographical references (p. 86-94).

Thesis (Ph. D.)--University of Connecticut, 2006. / (UnM)AAI3221565. Adviser: Glenn King. Source: Dissertation Abstracts International, Volume: 67-06, Section: B, page: 3122.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7403. Adviser: Klaus Schulten. Includes bibliographical references (leaves 72-79) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph. D.)--Rutgers University, 2010. / "Graduate Program in Computational Biology and Molecular Biophysics." Includes bibliographical references.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008. / Source: Dissertation Abstracts International, Volume: 69-11, Section: B, page: 6879. Adviser: Enrico Gratton. Includes bibliographical references (leaves 90-93) Available on microfilm from Pro Quest Information and Learning.