抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Adjacent cells share ions, second messengers and small metabolites through intercellular channels which are present in gap junctions. This type of intercellular communication permits coordinated cellular activity, a critical feature for organ homeostasis during development and adult life of multicellular organisms. Intercellular channels are structurally more complex than other ion channels, because a complete cell-to-cell channel spans two plasma membranes and results from the association of two half channels, or connexons, contributed separately by each of the two participating cells. Each connexon, in turn, is a multimeric assembly of protein subunits. The structural proteins comprising these channels, collectively called connexins, are members of a highly related multigene family consisting of at least 13 members. Since the cloning of the first connexin in 1986, considerable progress has been made in our understanding of the complex molecular switches that control the formation and permeability of intercellular channels. Analysis of the mechanisms of channel assembly has revealed the selectivity of inter-connexin interactions and uncovered novel characteristics of the channel permeability and gating behavior. Structure/function studies have begun to provide a molecular understanding of the significance of connexin diversity and demonstrated the unique regulation of connexins by tyrosine kinases and oncogenes. Finally, mutations in two connexin genes have been linked to human diseases. The development of more specific approaches (dominant negative mutants, knockouts, transgenes) to study the functional role of connexins in organ homeostasis is providing a new perception about the significance of connexin diversity and the regulation of intercellular communication.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1996.0001q.x

Connections with connexins: the molecular basis of direct intercellular signaling

Applications of ionic liquids at electrified interfaces to energy-storage systems, electrowetting devices, or nanojunction gating media cannot proceed without a deep understanding of the structure and properties of the interfacial double layer. This article provides a detailed critique of the present work on this problem. It promotes the point of view that future considerations of ionic liquids should be based on the modern statistical mechanics of dense Coulomb systems, or density-functional theory, rather than classical electrochemical theories which hinge on a dilute-solution approximation. The article will, however, contain more questions than answers. To trigger the discussion, it starts with a simplified original result. A new analytical formula is derived to rationalize the potential dependence of double-layer capacitance at a planar metal−ionic liquid interface. The theory behind it has a mean-field character, based on the Poisson−Boltzmann lattice-gas model, with a modification to account for the...

Double-Layer in Ionic Liquids: Paradigm Change?

In nanopore analytics, individual molecules pass through a single nanopore giving rise to detectable temporary blockades in ionic pore current. Reflecting its simplicity, nanopore analytics has gained popularity and can be conducted with natural protein as well as man-made polymeric and inorganic pores. The spectrum of detectable analytes ranges from nucleic acids, peptides, proteins, and biomolecular complexes to organic polymers and small molecules. Apart from being an analytical tool, nanopores have developed into a general platform technology to investigate the biophysics, physicochemistry, and chemistry of individual molecules (critical review, 310 references).

Nanopore analytics: sensing of single molecules

O presente estudo 3 tem como tema a produção e reprodução da vida de trabalhadores migrantes temporários nordestinos da construção civil que trabalham no Campus central da Universidade Federal de Santa Catarina — UFSC, em Florianópolis/SC. Seu objetivo principal é analisar as condições de vida, trabalho, moradia e escolarização dos trabalhadores diante do crescimento das migrações na atualidade. Na pesquisa empírica foi realizado um trabalho de campo nos canteiros de obras no campus, com o propósito de identificar as empresas que prestam serviço na universidade e também quais as empresas que empregavam maior número de trabalhadores migrantes temporários nordestinos. Na coleta de dados foram realizadas entrevistas semiestruturadas com os trabalhadores migrantes e com as empresas nos canteiros de obras da universidade. A pesquisa de campo envolveu ainda conversas informais com os trabalhadores migrantes, com as empresas e registros fotográficos.

Dissertação de mestrado

Ion transport between two baths of fixed ionic concentrations and applied electrostatic (ES) potential is analysed using a one-dimensional drift-diffusion (Poisson–Nernst–Planck, PNP) transport system designed to model biological ion channels. The ions are described as charged, hard spheres with excess chemical potentials computed from equilibrium density functional theory (DFT). The method of Rosenfeld (Rosenfeld Y 1993 J. Chem. Phys. 98 8126) is generalized to calculate the ES excess chemical potential in channels. A numerical algorithm for solving the set of integral–differential PNP/DFT equations is described and used to calculate flux through a calcium-selective ion channel.

https://iopscience.iop.org/article/10.1088/0953-8984/14/46/317/pdf

Coupling Poisson–Nernst–Planck and density functional theory to calculate ion flux

https://ftp.rush.edu/users/molebio/Bob_Eisenberg/Reprints/1998/Nonner_BJ-Vol75_1998.pdf

Ion Permeation and Glutamate Residues Linked by Poisson-Nernst-Planck Theory in L-Type Calcium Channels

https://ftp.rush.edu/users/molebio/Bob_Eisenberg/Reprints/2000/Nonner_BJ_2000.pdf

Binding and Selectivity in L-Type Calcium Channels:A Mean Spherical Approximation

A voltage clamp method for the membrane of Ranvier nodes is described and its error possibilities are discussed The following principle is used: the potential in the axoplasm of the node is kept constant by negative feedback whereas the potential of the external fluid is adjusted to give the desired membrane potential Potential changes in the nodal axoplasm are detected across one of the neighbouring internodes by the feedback amplifier input and are counteracted from its output across the other internode A grounded guard electrode prevents couplings across the external solution between the potential applying electrode at the node and the amplifier input electrode and permits to record the full size of the membrane potential A small air gap separates the guard and input electrode compartments; the other electrode compartments are isolated by vaseline seals

A new voltage clamp method for Ranvier nodes.

An approximate electrostatic (ES) excess free energy functional for charged, hard sphere fluids is presented. This functional is designed for systems with large density variations, but may also be applied to systems without such variations. Based on the Rosenfeld method of perturbation about a bulk (homogeneous) reference fluid [Y. Rosenfeld, J. Chem. Phys. 98, 8126 (1993)], the new ES functional replaces the reference fluid densities with a functional of the particle densities, called the RFD functional. The first-order direct correlation function (DCF) in the particle densities is computed using as input the first- and second-order DCFs in [rho(i)(x)], the inhomogeneous densities defined by the RFD functional. Because this formulation imposes no a priori constraints on the form of the RFD functional-it is valid for any choice of [rho(i)(x)]-the RFD functional may be chosen (1) so that the input DCFs (that is, DCFs in [rho(i)(x)]) may be approximated and (2) so the combination of [rho(i)(x)] and input DCFs yields a good estimate of the first-order DCF in the particle densities. In this way, the general problem of finding the excess free energy functional has been replaced by the specific problem of choosing a RFD functional. We present a particular RFD functional that, together with bulk formulations for the input DCFs, accurately reproduces the results of Monte Carlo simulations.

Wolfgang Nonner

Papers

Coupling Poisson–Nernst–Planck and density functional theory to calculate ion flux

Ion Permeation and Glutamate Residues Linked by Poisson-Nernst-Planck Theory in L-Type Calcium Channels

Binding and Selectivity in L-Type Calcium Channels:A Mean Spherical Approximation

A new voltage clamp method for Ranvier nodes.

Density functional theory of charged, hard-sphere fluids