11 research outputs found
Evolution of adaptation mechanisms: adaptation energy, stress, and oscillating death
In 1938, H. Selye proposed the notion of adaptation energy and published
"Experimental evidence supporting the conception of adaptation energy".
Adaptation of an animal to different factors appears as the spending of one
resource. Adaptation energy is a hypothetical extensive quantity spent for
adaptation. This term causes much debate when one takes it literally, as a
physical quantity, i.e. a sort of energy. The controversial points of view
impede the systematic use of the notion of adaptation energy despite
experimental evidence. Nevertheless, the response to many harmful factors often
has general non-specific form and we suggest that the mechanisms of
physiological adaptation admit a very general and nonspecific description.
We aim to demonstrate that Selye's adaptation energy is the cornerstone of
the top-down approach to modelling of non-specific adaptation processes. We
analyse Selye's axioms of adaptation energy together with Goldstone's
modifications and propose a series of models for interpretation of these
axioms. {\em Adaptation energy is considered as an internal coordinate on the
`dominant path' in the model of adaptation}. The phenomena of `oscillating
death' and `oscillating remission' are predicted on the base of the dynamical
models of adaptation. Natural selection plays a key role in the evolution of
mechanisms of physiological adaptation. We use the fitness optimization
approach to study of the distribution of resources for neutralization of
harmful factors, during adaptation to a multifactor environment, and analyse
the optimal strategies for different systems of factors
Dynamic and Thermodynamic Models of Adaptation
The concept of biological adaptation was closely connected to some
mathematical, engineering and physical ideas from the very beginning. Cannon in
his "The wisdom of the body" (1932) used the engineering vision of regulation.
In 1938, Selye enriched this approach by the notion of adaptation energy. This
term causes much debate when one takes it literally, i.e. as a sort of energy.
Selye did not use the language of mathematics, but the formalization of his
phenomenological theory in the spirit of thermodynamics was simple and led to
verifiable predictions. In 1980s, the dynamics of correlation and variance in
systems under adaptation to a load of environmental factors were studied and
the universal effect in ensembles of systems under a load of similar factors
was discovered: in a crisis, as a rule, even before the onset of obvious
symptoms of stress, the correlation increases together with variance (and
volatility). During 30 years, this effect has been supported by many
observations of groups of humans, mice, trees, grassy plants, and on financial
time series. In the last ten years, these results were supplemented by many new
experiments, from gene networks in cardiology and oncology to dynamics of
depression and clinical psychotherapy. Several systems of models were
developed: the thermodynamic-like theory of adaptation of ensembles and several
families of models of individual adaptation. Historically, the first group of
models was based on Selye's concept of adaptation energy and used fitness
estimates. Two other groups of models are based on the idea of hidden attractor
bifurcation and on the advection--diffusion model for distribution of
population in the space of physiological attributes. We explore this world of
models and experiments, starting with classic works, with particular attention
to the results of the last ten years and open questions.Comment: Review paper, 48 pages, 29 figures, 183 bibliography, the final
version accepted in Phys Life Re
The Development of Therapeutic Antibodies That Neutralize Homologous and Heterologous Genotypes of Dengue Virus Type 1
Antibody protection against flaviviruses is associated with the development of neutralizing antibodies against the viral envelope (E) protein. Prior studies with West Nile virus (WNV) identified therapeutic mouse and human monoclonal antibodies (MAbs) that recognized epitopes on domain III (DIII) of the E protein. To identify an analogous panel of neutralizing antibodies against DENV type-1 (DENV-1), we immunized mice with a genotype 2 strain of DENV-1 virus and generated 79 new MAbs, 16 of which strongly inhibited infection by the homologous virus and localized to DIII. Surprisingly, only two MAbs, DENV1-E105 and DENV1-E106, retained strong binding and neutralizing activity against all five DENV-1 genotypes. In an immunocompromised mouse model of infection, DENV1-E105 and DENV1-E106 exhibited therapeutic activity even when administered as a single dose four days after inoculation with a heterologous genotype 4 strain of DENV-1. Using epitope mapping and X-ray crystallographic analyses, we localized the neutralizing determinants for the strongly inhibitory MAbs to distinct regions on DIII. Interestingly, sequence variation in DIII alone failed to explain disparities in neutralizing potential of MAbs among different genotypes. Overall, our experiments define a complex structural epitope on DIII of DENV-1 that can be recognized by protective antibodies with therapeutic potential
Evolution of adaptation mechanisms: adaptation energy, stress, and oscillating death
Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.In 1938, Selye proposed the notion of adaptation energy and published ‘Experimental evidence supporting the conception of adaptation energy.’ Adaptation of an animal to different factors appears as the spending of one resource. Adaptation energy is a hypothetical extensive quantity spent for adaptation. This term causes much debate when one takes it literally, as a physical quantity, i.e. a sort of energy. The controversial points of view impede the systematic use of the notion of adaptation energy despite experimental evidence. Nevertheless, the response to many harmful factors often has general non-specific form and we suggest that the mechanisms of physiological adaptation admit a very general and nonspecific description.
We aim to demonstrate that Selye׳s adaptation energy is the cornerstone of the top-down approach to modelling of non-specific adaptation processes. We analyze Selye׳s axioms of adaptation energy together with Goldstone׳s modifications and propose a series of models for interpretation of these axioms. Adaptation energy is considered as an internal coordinate on the ‘dominant path’ in the model of adaptation. The phenomena of ‘oscillating death’ and ‘oscillating remission’ are predicted on the base of the dynamical models of adaptation. Natural selection plays a key role in the evolution of mechanisms of physiological adaptation. We use the fitness optimization approach to study of the distribution of resources for neutralization of harmful factors, during adaptation to a multifactor environment, and analyze the optimal strategies for different systems of factors
Aminopeptidase secreted by Chromobacterium sp. Panama inhibits dengue virus infection by degrading the E protein
Lens Status Influences the Association between CFH Polymorphisms and Age-Related Macular Degeneration: Findings from Two Population-Based Studies in Singapore
Role of Hydroxyprolines in the in Vitro Oxidative Folding and Biological Activity of Conotoxins
Dengue virus life cycle:viral and host factors modulating infectivity
Dengue virus (DENV 1-4) represents a major emerging arthropod-borne pathogen. All four DENV serotypes are prevalent in the (sub) tropical regions of the world and infect 50-100 million individuals annually. Whereas the majority of DENV infections proceed asymptomatically or result in self-limited dengue fever, an increasing number of patients present more severe manifestations, such as dengue hemorrhagic fever and dengue shock syndrome. In this review we will give an overview of the infectious life cycle of DENV and will discuss the viral and host factors that are important in controlling DENV infection