Thermal fluctuations of haemoglobin from different species: adaptation to temperature via conformational dynamics

Thermodynamic stability, configurational motions and internal forces of haemoglobin (Hb) of three endotherms (platypus, Ornithorhynchus anatinus; domestic chicken, Gallus gallus domesticus and human, Homo sapiens) and an ectotherm (salt water crocodile, Crocodylus porosus) were investigated using circular dichroism, incoherent elastic neutron scattering and coarse-grained Brownian dynamics simulations. The experimental results from Hb solutions revealed a direct correlation between protein resilience, melting temperature and average body temperature of the different species on the 0.1 ns time scale. Molecular forces appeared to be adapted to permit conformational fluctuations with a root mean square displacement close to 1.2 Å at the corresponding average body temperature of the endotherms. Strong forces within crocodile Hb maintain the amplitudes of motion within a narrow limit over the entire temperature range in which the animal lives. In fully hydrated powder samples of human and chicken, Hb mean square displacements and effective force constants on the 1 ns time scale showed no differences over the whole temperature range from 10 to 300 K, in contrast to the solution case. A complementary result of the study, therefore, is that one hydration layer is not sufficient to activate all conformational fluctuations of Hb in the pico- to nanosecond time scale which might be relevant for biological function. Coarse-grained Brownian dynamics simulations permitted to explore residue-specific effects. They indicated that temperature sensing of human and chicken Hb occurs mainly at residues lining internal cavities in the β-subunits. Copyright © The Royal Society 2012

Significados das hierarquias no trabalho em hospitais públicos brasileiros a partir de estudos empíricos

OBJETIVO: Compreender como as estruturas hierárquicas presentes na cultura organizacional de hospitais públicos brasileiros significam no trabalho hospitalar. MÉTODOS: O corpus da pesquisa originou-se em quatro teses e seis dissertações e foi organizado, analisado e interpretado sob a perspectiva da antropologia simbólica-interpretativa. RESULTADOS: Hospitais estão calcados na burocracia profissional e mecanicista, e as hierarquias, decorrentes dessas estruturas, produzem significados que interpretados indicam fragmentação das relações, disputas profissionais e distanciamentos, bem como conflitos e comportamentos subversivos no trabalho, respectivamente. CONCLUSÃO: As hierarquias em cada uma das burocracias encaminham diferentes enfrentamentos que desestabilizam os trabalhadores e seus processos de trabalho. Estratégias de reorientação e conscientização dos limites hierárquicos devem ser equacionadas, para que o trabalho seja otimizado.Objective: Understand the meaning, in hospital work, of hierarchical structures present in the organizational culture of Brazilian public hospitals. Methods: The corpus of research was originated in four theses and six dissertations, and was organized, analyzed and interpreted from the perspective of symbolic anthropology interpretation. Results: Hospitals copied the professional mechanistic bureaucracy and hierarchies, from these structures, produce meanings that indicate a fragmentation of relationships, professional disputes and separations, as well as conflicts and subversive behavior at work. Conclusion: The hierarchies in each of the bureaucracies created several clashes that disrupt the workers and their work processes. Reorientation strategies and awareness of the hierarchical boundaries should be studied so that the work is optimized.Objetivo: Comprender que significan, en el trabajo hospitalario, las estructuras jerárquicas presentes en la cultura organizacional de hospitales públicos brasileños. Métodos: El corpus de la investigación se originó en cuatro tesis y seis disertaciones y fue organizado, analizado y interpretado bajo la perspectiva de la antropología simbólica interpretativa. Resultados: Los Hospitales copian la burocracia profesional y mecanicista, y las jerarquías, provenientes de esas estructuras, producen significados que indican una fragmentación de las relaciones, disputas profesionales y distanciamientos, así como conflictos y comportamientos subversivos en el trabajo. Conclusión: Las jerarquías en cada una de las burocracias crean diferentes enfrentamientos que desestabilizan a los trabajadores y a sus procesos de trabajo. Estrategias de reorientación y concientización de los límites jerárquicos deben ser estudiadas, para que el trabajo sea optimizado

Resonant Waveguide Imaging of Living Systems: From Evanescent to Propagative Light

For more than 50 years, resonant waveguides (RWGs) have offered highly sensitive label-free sensing platforms to monitor surface processes such as protein adsorption, affinity binding, monolayer to multilayer build-up, bacteria and more generally adherent or confined living mammalian cells and tissues. Symmetrical planar dielectric RWG sensitivity was improved by metal coating of at least one of their surfaces for surface plasmon resonance undertaking (SPRWG). However, RWG sensitivity was often obtained at the expense of spatial resolution and could not compete with other high resolution fluorescence microscopies. For years, RWGs have only rarely been combined with high-resolution microscopy. Only recently, the improvement of intensity and phase light modulation techniques and the availability of low-cost high numerical aperture lenses have drastically changed the devices and methodologies based on RWGs. We illustrate in this chapter how these different technical and methodological evolutions have offered new, versatile, and powerful imaging tools to the biological community