Generation of high-quality charged particle beams during the acceleration of ions by high-power laser radiation

Numerous applications of protons and ions accelerated by laser radiation require charged particle beams of high quality (i.e., such that the ratio of the energy width of the beam to its mean energy is small). In order to produce beams with controlled quality, it is proposed to use two-layer targets in which the first layer consists of heavy multicharged ions and the second layer (thin and narrow in the transverse direction) consists of protons. The possibility of generating a high-quality proton beam in the interaction of ultraintense laser radiation with such a two-layer target is demonstrated by two-and three-dimensional particle-in-cell computer simulations.     

Selective interaction of cytoskeletal proteins with liposomes

A protein kinase activity analogous to that found in interferon-treated HeLa cells is detectable in human plasma rich in platelets. This kinase activity is manifested by the phosphorylation of an endogenous Mr 72000 protein which could be conveniently assayed after partial purification on poly(G)-Sepharose. Here, we show that the protein kinase system in the plasma consists of at least 2 components. The protein kinase is found to be localised in the platelets whereas most of the substrate (the Mr 72000 protein) is found free in the plasma and a fraction of it associated with the surface of platelets.     

Splenic macrophages enhance prolactin and luteinizing hormone action in rat luteal cell cultures.

We have reported that splenic macrophages play a role in the regulation of progestin secretion in rats. In this study, splenic macrophages were obtained from cycling rats at different estrous cycle stages and co-cultured with luteal cells from mid-pseudopregnant rats in the absence/presence of prolactin (PRL) or luteinizing hormone (LH). The effect of macrophages on the luteotropic action of PRL and LH was evaluated with 2 parameters, i.e. an increase in total progestin output (progesterone plus 20 alpha-hydroxyprgn-4-en-one [20 alpha-OHP]), and an increase in the progesterone to 20 alpha-OHP (P/20 alpha-OHP) secretion ratio. Splenic macrophages obtained from proestrous or metestrous rats enhanced the PRL action to increase the P/20 alpha-OHP secretion ratio, but those from estrous or diestrous donors did not. Only macrophages from proestrous donors enhanced the PRL action to increase the total progestin output. In contrast, the LH action increasing the P/20 alpha-OHP secretion ratio was enhanced by splenic macrophages regardless of the donors' estrous cycle stages. The LH action increasing the total progestin output was enhanced only by proestrous or metestrous macrophages. Therefore, if luteal cells are co-cultured with proestrous macrophages, the luteotropic actions of PRL and LH can be fully expressed. These results indicate that splenic macrophages directly act on luteal cells and enhance the luteotropic action of PRL and LH, and that this function of splenic macrophages is modified somehow according to the donors' estrous cycle stages.     

Role of outer coat in resistance of Bacillus megaterium spore

The outer coat fraction (OC-Fr) of Bacillus megaterium ATCC 12872 spore was isolated as a resistant residue after alkali extraction, sonic treatment, and pronase digestion of the spore coat preparation, and its backbone structure was determined by chemical analysis to be composed of galactosamine-6-phosphate (GalN-P) polymers with polypeptides and calcium. OC-Fr was not fully solubilized after ordinary acid hydrolysis. OC-Fr was insensitive to all hexosaminidases tested, and moreover, an isolated fragment, a pentamer of GalN-P, was also resistant to lysozyme and hexosaminidases even after N-acetylation, being sensitive to them to some extent after dephosphorylation. Molecular sieving experiments revealed that the outer coat limited the entry of compounds with a molecular weight of more than 2,000. Exchange of the metal on the spore surface also influenced the heat resistance. Spores of OC-Fr-deficient mutants were less resistant but were still much more resistant than the vegetative cells. These results suggest that the outer coat protects the contents of the spore against chemical, physical and enzymatic treatments owing to the chemical structure itself, composed mainly of GalN-P polymers, and the molecular sieving effect.     

Bombardment-mediated transformation of plant cells

Significance of bombardment-mediated transformation in plant research is discussed. Apart from general subjects related to this transformation study, a particular emphasis has been placed on the pollen and organelle transformation and on integration mechanism. Over 70 literatures related to this field are cited here.