Chen Yafei

Model for Influences of Magnetic Fields on Intracellular Calcium Oscillations

Based on the model of the two calcium stores developed by Goldbeter, the influence of external magnetic field on the calcium concentration has been discussed. We believe that the cell membrane is a major site of interaction for extremely-low-frequency (ELF) electromagnetic fields, and the permeability of ions can be changed with the changing electromagnetic fields. It is shown that magnetic field initiates intracellular calcium oscillation with a threshold in flux density, and that the calcium oscillations do not occur if the density of magnetic field is below the threshold. The results of theoretical calculation are consistent with that of the experiment. The intracellular free calcium concentrations of different cells exposed to the same magnetic fields are different from each other. It is indicated that the different behaviors such as oscillation, rise and invariability of calcium concentration are associated with the sort of cells.

Stochastic Four-State Mechanochemical Model of F1-ATPase

F1-ATPase, a part of ATP synthase, can synthesize and hydrolyze ATP moleculars in which the central γ-subunit rotates inside the α3 β3cylinder. A stochastic four-state mechanochemical coupling model of F1-ATPase is studied with the aid of the master equation. In this model, the ATP hydrolysis and synthesis are dependent on ATP, ADP, and Pi concentrations. The effects of ATP concentration, ADP concentration, and the external torque on the occupation probability of binding-state, the rotation rate and the diffusion coefficient of F1-ATPase are investigated. Moreover, the results from this model are compared with experiments. The mechanochemical mechanism F1-ATPase is qualitatively explained by the model.

Phenotypic characteristics of the first generation mealycup sage (Salvia Farinacea Benth.) induced by space radiation

To explore the biological effects of the space radiation, dry seeds of mealycup sage (Salvia farinacea Benth.) were flown with the Chinese space craft “Shen Zhou VIII”. The plants grown from the space exposed seeds displayed considerable changes in phenotypic traits. Eleven space exposed plants (EP) showed one month longer flowering period than the mean of the control plants (CP); 13 EP failed to flower and 23 bore flowers, within which 25 plants mutated in respect of flower production; leaf shape of EP showed two extremes: curling and folding, or totally smooth; 11 EP had mutated height, within which 6 plants were taller and 5 shorter than CP. These results demonstrated that space radiation could induce favorable mutations on plant seeds.

Comparison of Defense Related Enzyme between Oligochitosan Induced Protein Kinase Gene Silenced Transgenic Tobacco and Wild Type Tobacco

Oligochitosan (OC) could regulate plant defense responses in many aspects, but the basis signal transduction pathway is still unclear. In this study, we use transgenic (TG) tobacco as plant material whose OIPK gene was inhibited by antisense transformation, to identify the role oligochitosan induced protein kinase (OIPK) played in OC treated tobacco plants. Pathogen-related (PR) proteins enzymes activity assays and reverse transcriptional polymerase (RT-PCR) were conducted to compare the differences between TG and the corresponding wild type (WT) tobacco plants. Firstly, it was validated that OIPK could induce Phenylalanine ammonialyase (PAL, E.C. 4.3.1.5) and peroxidase (POD, E.C. 1.11.1.7 ) activities in respect to both activation time and activation fold after OC treatment, while OIPK had no influences on polyphenol oxidase (PPO, E.C.I.14.18.1) activity. Secondly, it was found that in TG tobacco, there was nearly just basis pal transcriptional expression after OC treatment, which showed that OIPK could determine pal gene expression in some sense. Thirdly, OIPK could enhance defense related gene transcription chi and glu activation intension and rapidity.

The Dissociation Rate Affects the Directed Motion of the Molecular Motor

Master equation is used in the paper under the condition of dissociation rate to study the directed motion of molecular motor. The drift velocity, the diffusion constant, the dwell time and the mean length of the motor are calculated. We found the dissociation rate affects the directed motion of the molecular motor.