Caenorhabditis elegans as an Alternative Model Host for Legionella pneumophila, and Protective Effects of Bifidobacterium infantis▿

The survival times of Caenorhabditis elegans worms infected with Legionella pneumophila from day 7.5 or later after hatching were shorter than those of uninfected worms. However, nematodes fed bifidobacteria prior to Legionella infection were resistant to Legionella. These nematodes may act as a unique alternative host for Legionella research

Autofluorescence as a noninvasive biomarker of senescence and advanced glycation end products in Caenorhabditis elegans

Abstract To assess the utility of autofluorescence as a noninvasive biomarker of senescence in Caenorhabditis elegans, we measured the autofluorescence of individual nematodes using spectrofluorometry. The fluorescence of each worm increased with age. Animals with lower fluorescence intensity exhibited longer life expectancy. When proteins extracted from worms were incubated with sugars, the fluorescence intensity and the concentration of advanced glycation end products (AGEs) increased over time. Ribose enhanced these changes not only in vitro but also in vivo. The glycation blocker rifampicin suppressed this rise in fluorescence. High-resolution mass spectrometry revealed that vitellogenins accumulated in old worms, and glycated vitellogenins emitted six-fold higher fluorescence than naive vitellogenins. The increase in fluorescence with ageing originates from glycated substances, and therefore could serve as a useful noninvasive biomarker of AGEs. C. elegans can serve as a new model to look for anti-AGE factors and to study the relationship between AGEs and senescence

Dynamical Structure of Nano-Meter-Sized Domains on a Vesicle(Poster session 1, New Frontiers in Colloidal Physics : A Bridge between Micro- and Macroscopic Concepts in Soft Matter)

この論文は国立情報学研究所の電子図書館事業により電子化されました。飽和リン脂質、不飽和リン脂質、コレステロールの3成分からなるモデル生体膜は、脂質アシル基の無秩序-秩序転移温度以下で相分離し、膜面上にドメイン構造を形成する。ナノメートルサイズのベシクルを用いることにより膜面上でのナノメートルスケールのドメインのダイナミクスを中性子スピンエコー法により調べた。臨界サイズに近い大きさを持つナノドメインはベシクル上で熱揺らぎにより融合・分裂を繰り返し、安定なモノドメイン構造にまで成長できない状態であると考えられる

Growth Dynamics of Domains in Ternary Fluid Vesicles

We have studied the growth dynamics of domains on ternary fluid vesicles composed of saturated (dipalmitoylphosphatidylcholine), unsaturated (dioleoylphosphatidylcholine) phosphatidylcholine lipids, and cholesterol using a fluorescence microscopy. The domain coarsening processes are classified into two types: normal coarsening and trapped coarsening. For the normal coarsening, the domains having flat circular shape grow in a diffusion-and-coalescence manner and phenomenologically the mean size grows as a power law of ∼t(2/3). The observed growth law is not described by a two-dimensional diffusion-and-coalescence growth mechanism following the Saffman and Delbrück theory, which may originate from the two-body hydrodynamic interactions between domains. For trapped coarsening, on the other hand, the domain coarsening is suppressed at a certain domain size because the repulsive interdomain interactions obstruct the coalescence of domains. The two-color imaging of the trapped domains reveals that the repulsive interactions are induced by the budding of domains. The model free energy consisting of the bending energy of domains, the bending energy of matrix, the line energy of domain boundary, and the translation energy of domains can describe the observed trapped coarsening. The trapping of domains is caused by the coupling between the phase separation and the membrane elasticity under the incompressibility constraint