Diffusion theory for the infection pathway of virus in a living cell

Gaussian fluctuation of the diffusion exponent of virus capsid in a living cell nucleus

In their work [Proc. Natl. Acad. Sci. USA 112 (2015) E5725], Bosse et al. experimentally showed that virus capsid exhibits not only normal diffusion but also anomalous diffusion in nucleus of a living cell. There, it was found that the distribution of fluctuations of the diffusion exponent characterizing them takes the Gaussian form, which is, quite remarkably, the same form for two different types of the virus. This suggests high robustness of such fluctuations. Here, the statistical property of local fluctuations of the diffusion exponent of the virus capsid in the nucleus is studied. A maxi…

The Energetic Cost of Building a Virus

Viruses are incapable of autonomous energy production. Although many experimental studies make it clear that viruses are parasitic entities that hijack the host's molecular resources, a detailed estimate for the energetic cost of viral synthesis is largely lacking. To quantify the energetic cost of viruses to their hosts, we enumerated the costs associated with two very distinct but representative DNA and RNA viruses, namely T4 and influenza. We found that for these viruses, translation of viral proteins is the most energetically expensive process. Interestingly, the cost of building a T4 phag…

Mechanics of diffusion-mediated budding and implications for virus replication and infection

Budding allows virus replication and macromolecular secretion in cells. It involves the formation of a bud, i.e. an outgrowth from the cell membrane that evolves into an envelope. The largest energetic barrier to bud formation is membrane deflection and is trespassed primarily thanks to nucleocapsid-membrane adhesion. Transmembrane proteins (TPs), which later form the virus ligands, are the main promotors of adhesion and can accommodate membrane bending thanks to an induced spontaneous curvature. Adhesive TPs must diffuse across the membrane from remote regions to gather on the bud surface, th…

Heterogeneous anomalous diffusion of virus in cytoplasm of a living cell

The infection pathway of virus in cytoplasm of a living cell is studied from the viewpoint of diffusion theory. The cytoplasm plays a role of a medium for stochastic motion of the virus contained in the endosome as well as the free virus. It is experimentally known that the exponent of anomalous diffusion fluctuates in localized areas of the cytoplasm. Here, generalizing fractional kinetic theory, such fluctuations are described in terms of the exponent locally distributed over the cytoplasm, and a theoretical proposition is presented for its statistical form. The proposed fluctuations may be …

Heterogeneous anomalous diffusion in view of superstatistics

It is experimentally known that virus exhibits stochastic motion in cytoplasm of a living cell in the free form as well as the form being contained in the endosome and the exponent of anomalous diffusion of the virus fluctuates depending on localized areas of the cytoplasm. Here, a theory is developed for establishing a generalized fractional kinetics for the infection pathway of the virus in the cytoplasm in view of superstatistics, which offers a general framework for describing nonequilibrium complex systems with two largely separated time scales. In the present theory, the existence of a l…

通过减毒麻疹疫苗病毒诱导的Vero细胞机械软化

Mechanical Softening of Vero Cells Induced by an Attenuated Measles Vaccine Virus

研究利用AFM和共聚焦显微镜分析病毒感染后Vero细胞的机械响应，发现感染24小时内细胞弹性模量显著降低，表明细胞软化，同时观察到黏弹性行为的变化，揭示了细胞骨架重塑对感染过程中黏弹性特性的影响。