Effects of ionic substances on the adsorption of egg white proteins to a stainless steel surface

The surface fouling of food processing equipment by proteins was studied by investigating the adsorption of egg white proteins to the surface of stainless steel (SS) at pH 7.4 and 30 °C, and particularly the effects of different types of ionic substances. Ovalbumin and ovomucoid, acidic egg white proteins, were less adsorbed in the presence of phosphate (P(i)), a multivalent anion, than in the presence of HEPES, an amphoteric ion. On the other hand, lysozyme, a basic egg white protein, was more adsorbed in the presence of P(i) than in the presence of HEPES. Citrate as another multivalent anion and taurine as another amphoteric ion affected the respective adsorption of those egg white proteins similarly to P(i) and HEPES. The adsorption of an egg white protein to an SS surface therefore depended on the combination of the type of protein and the effective charge of the coexisting ionic substance. This behaviour can be well explained by assuming that a small ionic substance precedes a protein in attaching to an SS surface, resulting in an alteration to the effective surface charge. Pretreating SS with a P(i) buffer lowered the amount of ovalbumin adsorbed with the HEPES buffer, demonstrating that P(i) can attach to and remain on the SS surface to affect the subsequent protein adsorption.     

Self-assemble gene delivery system for molecular targeting using nucleic acid aptamer

We have developed a novel vector constructed with pDNA, polyethylenimine (PEI), and mucin 1 (MUC1) aptamer for tumor-targeted gene delivery. The MUC1 aptamer and non-specific aptamer were employed to coat the pDNA/PEI complexes electrostatically and stable nanoparticles were formed. The addition of a non-specific aptamer to the pDNA/PEI complex decreased gene expression in the human lung cancer cell line, A549 cells expressing MUC1 regularly. At the same time, the pDNA/PEI/MUC1 aptamer complex showed higher gene expression than pDNA/PEI/non-specific aptamer complex. Furthermore, the pDNA/PEI/MUC1 aptamer complex showed markedly high gene expression in tumor-bearing mice; thus, pDNA/PEI/MUC1 aptamer complexes are useful as a tumor-targeted gene delivery system with high transfection efficiency.     

Tumor suppressor candidate 5 (TUSC5) is expressed in brown adipocytes

Rat brain endothelial cell derived gene-1 (BEC-1) had considerable homology with tumor suppressor candidate 5 (TUSC5). TUSC5 was expressed abundantly, and its mRNA was inhibited by cold exposure in rat brown adipose tissue (BAT). In the present study, we investigated its regulatory mechanism using primary cultured rat brown preadipocytes (RBPA) and Zucker lean rats (ZL). We found that: (1) TUSC5 mRNA began to increase in a manner similar to C/EBP-alpha, PPAR-gamma, and adiponectin during differentiation in RBPA; (2) neither beta3-adrenoceptor agonist BRL 37344 nor dexamethasone affected TUSC5 mRNA in RBPA; (3) propranolol did not block the decrease of TUSC5 mRNA by cold exposure in ZL; (4) BRL 37344 did not influence TUSC5 mRNA in ZL; and (5) dexamethasone inhibited TUSC5 mRNA in a dose-dependent manner similar to UCP-1 in ZL. These data suggested that TUSC5 is involved in the differentiation, and its expression is regulated independently of the beta-adrenergic pathway in BAT.     

Stimulation by glutamine and proline of HGF production in hepatic stellate cells

Amino acids regulate cellular functions in a variety of cell types. Most notably, leucine stimulates protein production through the mammalian target of rapamycin (mTOR)-dependent signaling pathway. We investigated the effect of amino acids on hepatocyte growth factor (HGF) production. Treatment with glutamine and proline, as well as leucine, increased HGF levels in the culture medium of a rat hepatic stellate cell clone in a dose-dependent manner. Up-regulation of phosphorylation of 70 kDa ribosomal protein S6 kinase and eukaryotic initiation factor 4E-binding protein 1 was not apparent in the cells after treatment with glutamine or proline. When rats received injections of glutamine or proline, hepatic and circulating HGF levels increased and peaked around 12 h after treatment. Glutamine and proline may have the potential to stimulate HGF production but the mechanism underlying this stimulation seems not to be through the mTOR-dependent signaling pathway.     

Evidence for processing enzymes in the abdominal gland of the newt, Cynops pyrrhogaster, that generate sodefrin from its biosynthetic precursor

Sodefrin (Ser-Ile-Pro-Ser-Lys-Asp-Ala-Leu-Leu-Lys) is a female-attracting peptide pheromone secreted by the abdominal gland of the male red-bellied newt, Cynops pyrrhogaster. Sequence analysis of a cDNA encoding sodefrin revealed that the peptide is located in the C-terminal region of its precursor protein (residues 177-186 of preprosodefrin) and extended from its C-terminus by the tripeptide sequence Ile(187)-Ser(188)-Ala(189) and flanked at its N-terminus by Leu(174)-Gly(175)-Arg(176). This suggests that sodefrin is generated by enzymatic cleavage at monobasic (Lys and Arg) sites within the precursor molecule. To demonstrate the presence in the abdominal gland of proteolytic enzymes capable of generating sodefrin, an enzymatic assay was developed using t-butoxycarbo-nyl (Boc)-Leu-Gly-Arg-4methylcoumaryl-7-amide (MCA) and Boc-Leu-Leu-Lys-MCA as synthetic substrates. A crude extract of the abdominal gland hydrolyzed both substrates to liberate 7-amino-4- methylcoumarin, suggesting that enzymes that generate sodefrin from its precursor molecule are present in the gland. The activity in the extract for cleaving Boc-Leu-Gly-Arg-MCA was optimal at pH 9.0 and 45 degrees C and for Boc-Leu-Leu-Lys-MCA at pH 9.0 and 40 degrees C. The effects of a range of specific inhibitors on activities in the extract suggest an involvement of enzymes belonging to the serine protease family. It was also demonstrated that enzymatic activity in an extract of the abdominal glands of sexually developed males was significantly (three- to six-fold; p<0.01) higher than that of sexually undeveloped males.     

Evaluation of the effects of a health education program on the improvement of hypercholesterolemia

This study examined the effects of a health education program based on the self- reliance and self-action philosophy and the use of group work methodology on hypercholesterolemia during and after the intervention period. Thirty-two people participated in the study. Measurement values were obtained at the commencement of the intervention (Baseline), during the 6-month intervention period, at the end of the 6-month intervention period (Middle Point) and 6 months after Middle Point (End Point). The average number of steps per day significantly increased during the 6-month intervention period. The energy intake and fat intake levels significantly decreased during the 6-month intervention period. Total cholesterol, triglyceride, and atherosclerosis-index levels significantly decreased between Baseline and End Point. The HDL cholesterol levels significantly increased between Baseline and End Point. Statistically significant decrease was also observed in total cholesterol and atherosclerosis-index levels between Baseline and Middle Point, and between Middle Point and End Point. It is concluded that the health education program based on self-reliance and self-action philosophy using a group work methodology is effective for improving hypercholesterolemia. Especially, the improvement in the serum total cholesterol and atherosclerosis-index levels was sustained even after the intervention period.     

(-)-epigallocatechin gallate inhibits prostaglandin D2-stimulated HSP27 induction via suppression of the p44/p42 MAP kinase pathway in osteoblasts

We previously reported that prostaglandin D2 (PGD2) stimulates heat shock protein 27 (HSP27) induction through p38 mitogen-activated protein (MAP) kinase, stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK) and p44/p42 MAP kinase in osteoblast-like MC3T3-E1 cells. In the present study, we investigated whether (-)-epigallocatechin gallate (EGCG), the major polyphenol found in green tea, affects the induction of HSP27 in these cells and the mechanism. EGCG significantly reduced the HSP27 induction stimulated by PGD2 without affecting the levels of HSP70. The PGD2-induced phosphorylation of p38 MAP kinase or SAPK/JNK was not affected by EGCG. On the contrary, EGCG markedly suppressed the PGD2-induced phosphorylation of p44/p42 MAP kinase and MEK1/2. However, the PGD2-induced phosphorylation of Raf-1 was not inhibited by EGCG. These results strongly suggest that EGCG suppresses the PGD2-stimulated induction of HSP27 at the point between Raf-1 and MEK1/2 in osteoblasts.     

Expression of α-taxilin in the murine gastrointestinal tract: potential implication in cell proliferation

α-Taxilin, a binding partner of the syntaxin family, is a candidate tumor marker. To gain insight into the physiological role of α-taxilin in normal tissues, we examined α-taxilin expression by Western blot and performed immunochemical analysis in the murine gastrointestinal tract where cell renewal vigorously occurs. α-Taxilin was expressed in the majority of the gastrointestinal tract and was prominently expressed in epithelial cells positive for Ki-67, a marker of actively proliferating cells. In the small intestine, α-taxilin was expressed in transient-amplifying cells and crypt base columnar cells intercalated among Paneth cells. In the corpus and antrum of the stomach, α-taxilin was expressed in cells localized in the lower pit and at the gland, respectively, but not in parietal or zymogenic cells. During development of the small intestine, α-taxilin was expressed in Ki-67-positive regions. Inhibition of cell proliferation by suppression of the Notch cascade using a γ-secretase inhibitor led to a decrease in α-taxilin- and Ki-67-positive cells in the stomach. These results suggest that expression of α-taxilin is regulated in parallel with cell proliferation in the murine gastrointestinal tract.