Molecular cloning and characterization of major vault protein of Echinococcus multilocularis.

The cDNA clone coding a major vault protein (MVP)-like protein was derived from Echinococcus multilocularis cysts. MVP is a main component of vault particles, which are the largest cytoplasmic ribonucleoprotein particles in eukaryotic cells. We sequenced and characterized E. multilocularis MVP (EmMVP). The nucleotide sequence of the emmvp cDNA clone was 2607 bp in the full length open reading frame and its deduced amino acid sequence had several signature motifs which were specific to MVP families. Immunoblot analysis with mouse anti-EmMVP antiserum revealed that crude antigens of E. multilocularis included EmMVP protein. Furthermore, our results showed that the expression of EmMVP protein in an Sf9 insect cell line using a baculovirus vector directed the formation of particles that shared similar biochemical characteristics with other vault proteins and the distinct vault-like morphology when negatively stained and examined by electron microscopy.

Comparative study on the nuclear hormone receptor activity of various phytochemicals and their metabolites by reporter gene assays using Chinese hamster ovary cells.

Phytochemicals are naturally present in a wide variety of plants, and have been suggested to exert a number of effects beneficial to human health. Several phytochemicals possess estrogenic activity through estrogen receptor alpha (ERalpha) and ERbeta, and are, therefore, termed phytoestrogens. In this study, we examined whether various phytochemicals have agonistic and/or antagonistic activity against six human nuclear receptors (ERalpha, ERbeta, androgen receptor (AR), glucocorticoid receptor (GR), thyroid hormone receptor alpha(1) (TRalpha(1)) and TRbeta(1)) by in vitro reporter gene assays using Chinese hamster ovary cells. Of the 31 phytochemicals tested, including flavonoids, isoflavonoids, coumestan, lignans, catechins and their metabolites, 20 compounds showed estrogenic activity via ERalpha and/or ERbeta, and we ranked these phytochemicals according to their estrogenic potency via ERalpha and ERbeta. As a result, coumestrol and genistein strongly activated ERalpha and ERbeta at very low concentrations of <1x10(-10) M. Most phytochemicals showing estrogenic activity also exhibited agonistic activity against ERbeta at lower concentrations than those for ERalpha, and two typical isoflavones, genistein and daidzein, in particular, showed a potent preference for ERbeta. Further, we found that baicalein has ERbeta antagonistic activity, and two compounds, enterolacton and O-desmethylangolensin, have AR antagonistic activity. Nevertheless, none of tested compounds showed AR agonistic activity together with GR, TRalpha(1) and TRbeta(1) agonistic/antagonistic activity. These results suggest that various phytochemicals or their metabolites preferentially interact with ERalpha/beta among the six nuclear hormone receptors tested, and that the ERbeta agonistic activity, in particular, of these compounds may be associated with various beneficial effects on human health.

[Inhibitory effects of hybrid liposomes on the growth of gastric tumor cells established from cotton rats].

We established cell-line (CoRa 622 G6) of gastric carcinoma using cotton rats with spontaneous malignant gastric carcinoma with hypergastrinaemia. Inhibitory effects of hybrid liposomes (HL) composed of dimyristoylphosphatidylcoline (DMPC) and polyoxyethylene (n) dodecyl ether (C(12)(EO)(n): n=21, 23, 25) on the growth of CoRa 622 G6 cells were clarified on the basis of WST-1 assay. Fusion and accumulation of HL including fluorescence probe into CoRa 622 G6 cell membrane were clarified using confocal laser microscopy and total internal reflection fluorescence microscopy. Induction of apoptosis of CoRa 622 G6 cells after the treatment with HL was observed in fluorescence micrographs on the basis of Annexin-V binding assay and TUNEL method using confocal laser microscopy. The results in this study could contribute to the chemotherapy for patients with gastric carcinoma.

Early and presymptomatic detection of Wilson's disease at the mandatory 3-year-old medical health care examination in Hokkaido Prefecture with the use of a novel automated urinary ceruloplasmin assay.

Wilson's disease (WND) is an autosomal recessive disorder of copper (Cu) accumulation leading to liver and/or brain damage. Oral chelating agents and diet are effective in treating WND. However, once irreversible damage has occurred, the effect of treatment is diminished and the patient's quality of life is compromised. For these reasons an effective method for screening has been needed for early detection of presymptomatic patients. We conducted an early and presymptomatic detection of WND using a novel automated assay of ceruloplasmin (Cp) concentration in urine and selected the mandatory medical health care examination for 3-year-old children in Hokkaido Prefecture (the largest administrative division in Japan) as a sampling point. We measured urinary Cp concentrations in 11,362 children using an immunological latex agglutination assay kit developed by us. Among these children we identified a positive case with markedly reduced urinary Cp concentration. Detailed medical examination provided no clinical manifestations to support the diagnosis of WND, although serum Cp and Cu levels were remarkably low in this case. Therefore, we analyzed the WND gene in order to confirm the diagnosis. Sequence analysis revealed that the case was compound heterozygous for the WND gene mutations 2871del.C and D1296N. According to the Ferenci scoring system for WND diagnosis, the case was established as a WND patient at the presymptomatic stage. Consequently, the patient has maintained a good quality of life under medical treatment with polaprezinc administration to date. Our investigation suggests that the screening system for WND using the automated urinary assay at the mandatory medical health care examination for 3-year-old children is a noninvasive and efficient method for the early and presymptomatic diagnosis of WND.

Characterization of various recombinant antigens from Echinococcus multilocularis for use in the immunodiagnosis.

Using four clones isolated from Echinococcus multilocularis cDNA library with alveolar echinococcosis (AE) patient sera, various antigens were expressed as ThioHis tag-fused protein. Recombinant EmII/3 antigen was produced as the five fragments divided into the N-terminal (#5 and #5s), the central (#6 and #6s) and the C-terminal domain (#7). Immunoblot analysis revealed that the #7 showed significant reactivity whereas those of #5 and #5s were relatively low. The #6 and #6s also showed lower reactivity than that of #7, although the two minor bands of #6 reacted with every serum. These results suggested that an immunodominant region of EmII/3 locate within the C-terminal one third. The #8s recombinant antigen, Ser23-Glu176 of actin filament fragmenting protein (AFFP), apparently reacted with the AE patient sera, while the #1 antigen synthesized as a full-length antigen BI did not show such high reactivity. Thus, #7 and #8s antigens showed significant potential for use in immunodetection of AE. In addition, the specific antibodies against #7 and #8s reacted with specific antigens in crude extract of E. multilocularis cyst, indicating that these antigens retained antigenicity common to native EmII/3 and AFFP, respectively.

Nuclear export of adenovirus E4orf6 protein is necessary for its ability to antagonize apoptotic activity of BH3-only proteins.

The adenovirus E4orf6 is a viral oncoprotein known to cooperate with the E1A gene product in transforming primary murine cells. It has been shown to inhibit the apoptotic activities of p53 and p73 through direct binding to these proteins. Here, we demonstrate that the adenovirus E4orf6 protein inhibits apoptosis mediated by BNIP3 and Bik, which are BH3-only proteins of the Bcl-2 family. This activity was not mediated by p53 and p73 because E4orf6 had the same effect on the apoptosis in Saos-2 cells that do not express p53-related genes. It was also ascertained that E4orf6 could change the mitochondrial localization of BNIP3 and Bik. A mutant lacking the nuclear export signal of E4orf6 failed to inhibit apoptosis and to translocate BNIP3 protein from the mitochondria. Moreover, it was also established that E4orf6 was able to interact with BNIP3 and Bik. In BNIP3 protein, the region required for the interaction included the transmembrane domain, which is required for the localization of BNIP3 to the mitochondria. These results suggest that E4orf6 is exported from the nucleus to the cytoplasm, enabling it to interact with BH3-only proteins, eventually leading to the inhibition of apoptotic activity.