Interactions of alpha-lactalbumins with lipid vesicles studied by tryptophan fluorescence

Complexes of alpha-lactalbumin (alpha-LA)1 with dimyristoylphosphatidylcholine (DMPC) or dipalmitoylphosphatidylcholine (DPPC) liposomes at pH 8 and at pH 2 have been obtained by means of gel filtration. Thermal denaturation of alpha-LA complexes of DMPC or DPPC at pH 8 was found to depend on the saturation of protein by metal cations. The intrinsic fluorescence of DMPC-alpha-LA and DPPC-alpha-LA was sensitive to two thermal transitions. The first transition corresponded to the Tc of the lipid vesicles, while the second transition arose from the denaturation of the protein. Fluorescence spectrum position suggested that at low temperature tryptophan accessibility increases upon protein-DMPC or protein-DPPC association. At temperatures above the protein transition (70 degrees C) tryptophan appears to interact significantly with the apolar phase of DMPC and DPPC, evidenced by spectral blue shifts. Whereas the free protein at pH 2 adopts the molten globule (MG) state and is characterized by the absence of a thermal transition, the rapidly-isolated DMPC-alpha-LA complex was characterized by the appearance of a distinct fluorescence thermal transition between 50 and 60 degrees C. This result is consistent with a model of a partially-inserted form of alpha-LA which may possess some degree of tertiary structure and therefore unfolds cooperatively.     

从PC串行口获取电源的微控制器编程器

与PC的USB端口一样,PC的串行端口在某些情况下也可以作为一种电源.USB端口可以提供高达5V 500mA,但串行口提供的电能较低.虽然串行口的容量有限,但它的功率仍可用作今天电子产品的一个方便的电源.     

Programmed changes of cell cycle regulators by serum deprivation regardless of skeletal myocyte differentiation

Permanent withdrawal of skeletal myoblasts from the cell cycle precedes differentiation. We examined the changes of protein levels of cell cycle regulators and the activities of CDKs in differentiating (by serum deprivation) or in differentiation-inhibited (by serum deprivation + TGF-beta1 treated) C2C12 skeletal myocytes. Regardless of differentiation, protein levels of most cyclins declined over time while this effect was delayed slightly by TGF-beta1 for cyclins D1 and F. Although the protein levels of CDKs gradually decreased over time, the activities of CDK2 and cdc2 decreased dramatically between 0 and 12 h after serum deprivation in both groups. Decreased CDK2 and cdc2 activities were temporally related to decreased DNA synthesis. While the p27KIP1 protein increased in both groups, the p21CIP1 protein increased only in differentiating cells. In vivo, protein expressions of cyclins, CDKs, and p21CIP1 were high in fetal, but almost undetectable in adult skeletal muscle. In contrast, the levels of p27KIP1 protein in skeletal muscle were high throughout development. Thus, changes of cell cycle regulators in differentiating C2C12 myocytes paralleled those during skeletal muscle development of mice. These results suggest that the rapid reduction of DNA synthesis and activities of CDKs slow reduction of protein levels of cyclins and CDKs, and that the increase of p27KIP1 are programmed mechanisms upon mitogen deprivation regardless of differentiation in skeletal myocytes.     

New technique for the fabrication of conductive polymer/insulating polymer composite films

The electrochemical polymerization of pyrrole on an ITO (indium‐tin oxide)‐coated glass electrode with an insulating film of poly(vinyl alcohol), PVA, produces a flexible composite polymer film with electrical, optical, and electrochemical properties very similar to polypyrrole (PPy). The rate of electrochemical polymerization depends on the diffusion of the electrolyte across the PVA film to the ITO electrode. In particular, hydrophilic solvents easily penetrate into the PVA film. By applying this new process, we demonstrate a unique method of forming electrically conductive patterns in PVA film. It will be possible to develop electrodes for electrical stimulation of the nervous system using a conducting polymer, PPy. By a similar technique we have fabricated poly(3,4‐ethylenedioxythiophene), PEDOT/PVA, composite films and have investigated their electrochemical basic properties. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(4): 1–8, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21055     

Influence of pH,concentration of sodium lactate as an additive and ultrasonic treatment on synthesis of zinc phosphate white pigments

Zinc oxide that has the photocatalytic activity is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, zinc phosphates were prepared from zinc nitrate and phosphoric acid at pH 5 and 7 with and without the addition of sodium lactate and ultrasonic treatment as a novel white pigment for use in cosmetics. The chemical composition, powder properties, photocatalytic activity, colour phase, moisture retention and smoothness of the zinc phosphates were studied. The obtained materials had a Zn/P ratio of about 1.5, which corresponds to zinc orthophosphate Zn₃(PO₄)₂. Samples prepared with ultrasonic treatment indicated the high ratios of large particles in scanning electron microscopy images and particle‐size distributions. The photocatalytic activity of these zinc phosphate particles was too less to protect the sebum on the skin. The materials obtained and their thermal products at 100°C showed a high reflectance within the range of visible light. The slipping resistance and roughness of the powder were enough low for use in cosmetics.     

Gene expression in gastric carcinoma tissues

In gastric cancer, the expression of c-myc protein and mRNA were investigated to determine the mechanism of inappropriate expression of c-myc gene. Correlation between clinical findings and the gene was also studied. Forty-six lesions of 43 patients were investigated by immunohistochemical staining technique. The expression of c-myc mRNA in the small fresh tissues of the same patients was detected by Northern blot hybridization. Results were as follows: 1) c-myc protein was detected in 20 lesions. The expression of c-myc protein was not differed in histological types ans stages of the lesions. 2) The level of c-myc mRNA expression was increased. In 34 cancer lesions than normal mucosa of the same patients. The overexpression of c-myc mRNA in the cancer lesion was more frequently found in early-stage cancer than in advanced-stage cancer. However, no difference was seen in histological types. 3) c-myc protein expression was correlated with mRNA overexpression. 4) In early-stage cancer, the rate of the lesions found to express excess c-myc protein was not so frequent as that of mRNA overexpression. In conclusion, c-myc mRNA overexpression was thought to cause inappropriate protein expression in gastric cancer and c-myc gene overexpression might happen already in the early-stage of gastric cancer suggesting it had a role in carcinogenesis.