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Trace elements play important roles in cells. Nuclear techniques as traditional PIXE, SPM and SR-XRM provide solid tools for quantitative element analysis. The article presents element-distribution maps of endometrium, nerve cell and relative quantity tables. Advantages of PIXE, SPM and SR-XRM techniques, especially in application to cell biology, are discussed. PIXE has a large beam and is convenient in measuring a large quantity of samples. SPM gives element-distribution maps owing to its high resolution. SR-XRM tells quantity of elements by its good sensitivity and nondestructive irradiation. The combination of PIXE, SPM and SR-XRM demonstrates that Zn is a component of cell membrane and is proved to be a complementary way which will open vast vistas for cell analysis.

In recent years, a delivery system based on atomic force microscopy (AFM) has been developed to transport nucleic acids, proteins and drugs to single adherent cell by controlling the indentation process. However, the transportation efficiency is limited by the low penetration rate of the common commercial AFM probe. The tip of commercial AFM probe is blunt and it is hard for blunt tip to insert into the soft cell membrane. In this study, dissipative particle dynamics (DPD) simulations were applied to investigate the penetration process of the AFM probe into the cell membrane subjected to different strain states. It was observed that the AFM tip moved down a shorter distance to penetrate the stretched lipid membrane compared with unstretched membrane. Moreover, the threshold value of penetrating force decreased as cell membrane extended. The short indentation time and small force can reduce the probability of cell membrane collapse, therefore it is easier for the AFM tip to penetrate the cell. We also performed the AFM indentation experiments via AFM to investigate the relationship between penetrating force and indentation speed. This work provides a potential way to improve the efficiency of cell transfection by using the AFM delivery system.

The phenomenon of patterned distribution of pH near the cell membrane of the algae Chara corallina upon illumination is well-known. In this paper, we develop a mathematical model, based on the detailed kinetic analysis of proton fluxes across the cell membrane, to explain this phenomenon. The model yields two coupled nonlinear partial differential equations which describe the spatial dynamics of proton concentration changes and transmembrane potential generation. The experimental observation of pH pattern formation, its period and amplitude of oscillation, and also its hysteresis in response to changing illumination, are all reproduced by our model. A comparison of experimental results and predictions of our theory is made. Finally, a mechanism for pattern formation in Chara corallina is proposed.

Cell membrane’s fatty acids (FAs) have been carefully investigated in neurons and platelets in order to study a possible connection to psychopathologies. An important link between the FA distribution and membrane dynamics appears to emerge with the cytoskeleton dynamics. Microtubules (MTs) in particular have been implicated in some recent quantum consciousness models and analyses. The recently proposed quantum model of Craddock et al. (2014) states that MTs possess structural and functional characteristics that are consistent with collective quantum coherent excitations in the aromatic groups of their tryptophan residues. These excitations are consistent with a clocking mechanism on a sub-nanosecond scale. This mechanism and analogous phenomena in light-harvesting complexes in plants and bacteria, are induced by photons and have been touted as evidence of quantum processes in biology. A possible source of intra-cellular photons could be membrane lipid peroxidation processes, so the FA profile could then be linked to the bio-photon emission. The model presented here suggests new ways to understand the role serotonin plays in relation to FAs. In plants, tryptophan conversion of light to exciton energy can participate in the directional orientation of leaves toward sunlight. Since serotonin is structurally similar to tryptophan, in the human brain, neurons could use tryptophan to capture photons and also use serotonin to initiate movement toward the source of light. Hence, we postulate two possible new roles for serotonin: (1) as an antioxidant, in order to counter-balance the oxidative effect of FAs, and (2) to participate in quantum interactions with MTs, in the same way as anesthetics and psychoactive compounds have been recently shown to act. In this latter case, the FA profile could provide an indirect measure of serotonin levels.

Lipids in cell membranes are organized in cholesterol-rich domains that are involved in many important cellular functions. Depending on the cell state, such structures are believed to develop covering a wide range of submicrometric sizes and different levels of stability. Using a simple Monte Carlo approach I demonstrate that when the membrane lipid mixture approaches a phase boundary, the cell has several mechanisms to tune both the size and stability of these domains. Cholesterol levels variation, presence of ceramides and insertion of proteins provide plausible mechanisms for the control of the nanoscale lipid organization in cell membranes.

While carbon nanotubes have been put into massive practical industrial, environmental and biomedicine applications, the cytotoxicity effects or the effect to the ionic channels they bring into the living cells need to be thoroughly investigated. In this work, molecular dynamic simulations have been carried out to investigate the ionic diffusion through the single wall armchair carbon nanotube embedded right inside the cell membrane. By modeling a two-membrane system, we build a virtual cytoplasm environment including a cell chamber and an extracellular space, in which a certain amount of solute is dissolved. The system is first brought to its equilibrium by deployment of minimization and then simulated. The results suggested that carbon nanotubes (CNTs) with size less than (12, 12) shall be less cytotoxic since it does not bring any ionic diffusion through the CNT channel, so as to maintain active cytoplasm environment. Another phenomenon we observed is a notable shifting angle of the carbon nanotube which was normal to the surface of cell membrane initially. In general, the inclination angle of the carbon nanotube increases with its radius.

The biological effect of ultrasound depends significantly on the sound intensity, frequency and the tissue properties. Both reversible effect and irreversible effect exist. This paper presents some biological and physical explanations, including (1) ultrasound can change the permeation of cell membranes. The stimulation of ultrasound changes the structure of cell, causing the change the electricity of cell membrane; (2) the ultrasound of low frequency can stimulate some plant and animal cells' growth. The pH is indispensable to the growth of cell and ultrasound will change the pH; and (3) we give some ultrasound explanations about the killing effect on cancer cells.