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

https://www.cell.com/cell/pdf/0092-8674(93)90509-O.pdf

Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programed cell death

Rapid progress in deciphering the biological mechanism of Alzheimer's disease (AD) has arisen from the application of molecular and cell biology to this complex disorder of the limbic and association cortices. In turn, new insights into fundamental aspects of protein biology have resulted from research on the disease. This beneficial interplay between basic and applied cell biology is well illustrated by advances in understanding the genotype-to-phenotype relationships of familial Alzheimer's disease. All four genes definitively linked to inherited forms of the disease to date have been shown to increase the production and/or deposition of amyloid β-protein in the brain. In particular, evidence that the presenilin proteins, mutations in which cause the most aggressive form of inherited AD, lead to altered intramembranous cleavage of the β-amyloid precursor protein by the protease called γ-secretase has spurred progress toward novel therapeutics. The finding that presenilin itself may be the long-sought γ-...

Alzheimer's Disease: Genes, Proteins, and Therapy

Normal tissue cells are generally not viable when suspended in a fluid and are therefore said to be anchorage dependent. Such cells must adhere to a solid, but a solid can be as rigid as glass or softer than a baby's skin. The behavior of some cells on soft materials is characteristic of important phenotypes; for example, cell growth on soft agar gels is used to identify cancer cells. However, an understanding of how tissue cells-including fibroblasts, myocytes, neurons, and other cell types-sense matrix stiffness is just emerging with quantitative studies of cells adhering to gels (or to other cells) with which elasticity can be tuned to approximate that of tissues. Key roles in molecular pathways are played by adhesion complexes and the actinmyosin cytoskeleton, whose contractile forces are transmitted through transcellular structures. The feedback of local matrix stiffness on cell state likely has important implications for development, differentiation, disease, and regeneration.

/pdf/tissue-cells-feel-and-respond-to-the-stiffness-of-their-6dx0rumap6.pdf

Tissue Cells Feel and Respond to the Stiffness of Their Substrate

This paper describes a procedure that makes it possible to design and fabricate (including sealing) microfluidic systems in an elastomeric materialpoly(dimethylsiloxane) (PDMS)in less than 24 h. A network of microfluidic channels (with width >20 μm) is designed in a CAD program. This design is converted into a transparency by a high-resolution printer; this transparency is used as a mask in photolithography to create a master in positive relief photoresist. PDMS cast against the master yields a polymeric replica containing a network of channels. The surface of this replica, and that of a flat slab of PDMS, are oxidized in an oxygen plasma. These oxidized surfaces seal tightly and irreversibly when brought into conformal contact. Oxidized PDMS also seals irreversibly to other materials used in microfluidic systems, such as glass, silicon, silicon oxide, and oxidized polystyrene; a number of substrates for devices are, therefore, practical options. Oxidation of the PDMS has the additional advantage that it ...

Rapid prototyping of microfluidic systems in poly(dimethylsiloxane)

A method and apparatus for illuminating a subject with deep UV light and detecting 2-dimensional image information, e.g., a transmission image, fluorescence image, reflected light image, etc. The subject may be illuminated with a light pulse having a duration of 2 seconds or less and one or more components with a wavelength of between about 150 nm to about 300 nm. The light pulse may be arranged so as to minimize or eliminate any detrimental effect on the functioning of the subject, e.g., on a living cell. A concentration, mass, quantum yield, absorbance or other characteristics of one or more compounds in the subject may be determined based on one or more 2-dimensional images obtained of the subject. An illumination beam having left and right circularly polarized components may be generated, e.g., for circular dichroism analysis of a subject.

Method and apparatus for generating a circularly polarized illumination beam

Protein purification methods &3-A practical approach: Edited by E. L. V. Harris and S. Angal. New York: Oxford University Press. (1990). 336 pp. $40.00

The stalk of Vorticella convallaria, a sessile microorganism, is a model for calcium-powered cellular contraction and biomimetic actuators because of its high contraction speed and unique energy source. Usually, the stalk coiling follows the contraction of the cell body with a time delay (latent period), and it propagates from the cell body side to the root side. The dynamics and energetics of contracting V. convallaria have been studied by applying a stall force to the cell and thus slowing down the stalk contraction. This study exerted an extrinsic stall force to V. convallaria by applying drag force to V. convallaria cells using a microchannel and found that the propagation speed of the stalk coiling was not affected by the stall force, which is similar to the stalk coiling propagation of V. convallaria contracting in a stagnant viscous liquid. In contrast, the minimum latent period increased with the stall force, which enabled estimation of the maximum rate of contraction force development of the V. convallaria stalk.

Stall force does not affect the stalk coiling propagation of Vorticella convallaria

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S143192760001206X

New Strategy for Crystallographic Reconstruction of Biological Bundle-Like Structures

We describe a low-cost, wireless compatible biosensor for optical microarray based applications. With the increasing use of microarray platforms in biosensors, as well as high-throughput screening in the areas of research and diagnostics, it has become necessary to develop a low cost imager compatible with existing mu array platforms, enabling microarray technology to be widely utilized outside of a laboratory setting. The incorporation of a wireless interface enables the possibility of a package-free biosensor for direct integration into biological environments. To accomplish this we developed an imaging platform using a standard digital CMOS process that allows direct integration of electronics, while levering the optical properties of silicon photodiodes and quantum dots to eliminate the need for optical filters and lenses, enabling a low-cost integrated solution. As a proof of concept, we demonstrate the detection of a 20 nM concentration of streptavidin without the use of optics.

Paul Matsudaira

Papers

Method and apparatus for generating a circularly polarized illumination beam

Protein purification methods &3-A practical approach: Edited by E. L. V. Harris and S. Angal. New York: Oxford University Press. (1990). 336 pp. $40.00

Stall force does not affect the stalk coiling propagation of Vorticella convallaria

New Strategy for Crystallographic Reconstruction of Biological Bundle-Like Structures

Wireless-compatible optics-free microarray imager