Role of the Gln/Glu residues of trichocellins A-II/B-II in ion-channel formation in lipid membranes and catecholamine secretion from chromaffin cells

Trichocellins (TC) A-II and B-II, 20-residue peptaibols isolated from conidia of the fungus Trichoderma viride, have the same sequence except for the residue at position 18. Both TCs were found to form voltage-dependent ion-channels in bilayer lipid membranes (BLM) and to induce catecholamine secretion from bovine adrenal chromaffin cells through Ca2+ influx. TC-A-II (Gln18, neutral) was more effective than TC-B-II (Glu18, charged) for macroscopic current induction in BLMs and for catecholamine secretion from chromaffin cells, suggesting that Glu18 is unfavorable for the ion-channel formation in BLMs and chromaffin cell membranes. Nevertheless, single-channel recordings indicated that TC-B-II forms larger pores with longer open lifetimes than those of TC-A-II. This indicates that the negatively charged carboxyl group of Glu at position 18 stabilizes larger pores. The effects of the negative charge of Glu18 on the activities were confirmed by the use of a TC-B-II analog containing the methyl ester of Glu18.

Localization of a breast cancer tumour-suppressor gene to a 3-cM interval within chromosomal region 16q22

Allelic losses on chromosome 16q in tumour cells are frequent in a variety of malignancies, suggesting the presence of one or more tumour-suppressor genes in the region. Among 210 sporadic breast cancers we examined using 15 microsatellite markers on the long arm of chromosome 16, heterozygosity for at least one locus was lost in 141 (67%). Detailed deletion mapping revealed two distinct commonly deleted regions. One region was defined as a 3-cM interval flanked by markers D16S512 and D16S515 at 16q22; the second consisted of a 9.5-cM interval flanked by markers D16S498 and D16S303 at q24.3. Allelic loss on 16q was observed frequently in small tumours, tumours without lymph node metastasis and tumours of the non-invasive histological type as well as in tumours of more advanced phenotype, suggesting that inactivation of one of at least two tumour-suppressor genes on 16q plays a role in early stage breast carcinogenesis.

[Evaluation of a method to determine the myocardial uptake from 123I-BMIPP myocardial SPECT and its significance]

We examined methods of calculating myocardial uptake (TU) of 123I-BMIPP by SPECT, and compared TU to heart function (ejection fraction (EF), cardiac output (CO), cardiac index (CI)) calculated by left ventriculography. Forty-two patients with acute myocardial infarction were classified into 5 groups; within 1 week (I), from 1 to 2 weeks (II), from 2 weeks to 1.5 months (III), from 1.5 to 3 months (IV) and more than 3 months (V) after percutaneous transluminal coronary angioplasty (PTCA). Chest depth (Tw) was calculated by measuring the thoracic absorption rate of 123I. In calculating TU, the myocardial count was calculated from short-axis tomograms, and then absorption was corrected using Tw to calculate each value on early-phase image (E) and delay-phase image (D). The influence of lung uptake on myocardial count was only 1.76%. When TU was compared to heart function, there were correlations between group I and group V. Especially in group V D-TU was a significantly correlated with heart function. In heart function CI, but not EF nor CO, was significantly correlated with TU. It was suggested that the correlation between TU and heart function reflected the infarct condition before PTCA in group I, and that the individual difference in recovery of fatty acid metabolism in group V. The significant correlation between D-TU and CI suggests that D-TU reflects heart function and fatty acid metabolism, although TU is influenced by differences in physical status.

Generation of packaging cell lines for pseudotyped retroviral vectors of the G protein of vesicular stomatitis virus by using a modified tetracycline inducible system

We have previously shown that the G protein of vesicular stomatitis virus (VSV-G) can be incorporated into the virions of retroviruses. Since expression of VSV-G is toxic to most mammalian cells, development of stable VSV-G packaging cell lines requires inducible VSV-G expression. We have modified the tetracycline-inducible system by fusing the ligand binding domain of the estrogen receptor to the carboxy terminus of a tetracycline-regulated transactivator. Using this system, we show that VSV-G expression is tetracycline-dependent and can be modulated by beta-estradiol. Stable packaging cell lines can readily be established and high-titer pseudotyped retroviral vectors can be generated upon induction of VSV-G expression.

Inducible gene expression by retrovirus-mediated transfer of a modified tetracycline-regulated system

The ability to regulate gene expression via exogenous stimuli will facilitate the study of gene functions in mammalian cells. In the present study, we modified the tetracycline-controlled inducible system by the addition of the ligand-binding domain of the estrogen receptor to the carboxy terminus of the tTA transactivator. A single retroviral vector can transduce both the transactivator gene and the gene of interest controlled by the tTA-inducible promoter into mammalian cells. We show that cell lines expressing the transactivator can readily be established and that expression of the gene of interest depends on the removal of tetracycline and the addition of estrogen. By using this system, cell lines with inducible expression of the G protein of vesicular stomatitis virus, a potentially toxic gene product, were established. The combination of a powerful inducible system and retrovirus-mediated gene transfer can not only be used to study gene function but may also be applied in the future to clinical trials in human gene therapy.

Role of proline residue in the channel-forming and catecholamine-releasing activities of the peptaibol, trichosporin-B-VIa

Trichosporin-B-VIa (TS-B-VIa) has a Pro14-kinked helical structure which is considered to be important for the formation of peptaibol-type ion-channels in lipid bilayer membranes. TS-B-VIa and its analog [Aib14]TS-B-VIa with Pro-->Aib substitution at position 14, resulting in a straight helical structure, were tested for ion-channel-forming activity in planar lipid bilayer membranes and for ability to induce catecholamine secretion from cultured bovine adrenal chromaffin cells. Voltage-dependent multi-channel conductance, which is characteristic of TS-B-VIa, was also observed for [Aib14]TS-B-VIa. In single-channel measurements, current fluctuations induced by [Aib14]TS-B-VIa had a shorter life-time and showed fewer substates than those induced by TS-B-VIa. Catecholamine secretion induced by these peptides at low concentrations is completely Ca(2+)-dependent. At high concentrations, TS-B-VIa-induced secretion was partly independent of external Ca2+, but this was not the case for the analog. The differences of behavior can be explained in terms of the differences of hydrophobicity, and magnitude of dipole moment due to the conformational changes around position 14 and the C-terminal domain caused by the Pro-->Aib substitution.

Pathway for Ca2+ influx into cells by trichosporin-B-VIa, an alpha-aminoisobutyric acid-containing peptide, from the fungus Trichoderma polysporum

Trichosporin (TS) -B-VIa, a fungal alpha-aminoisobutyric acid (Aib) -containing peptide consisting of 19 amino acid residues and a phenylalaninol, produced both 45Ca2+ influx into bovine adrenal chromaffin cells and catecholamine secretion from the cells. The secretion induced by TS-B-VIa at lower concentrations (2-5 microM) was completely dependent on the external Ca2+, while that induced by TS-B-VIa at higher concentrations (10-30 microM) was partly independent of the Ca2+. The concentration-response curves (2-5 microM) for the TS-B-VIa-induced Ca2+ influx and secretion correlated well. The TS-B-VIa (at 5 microM) -induced secretion was not antagonized by diltiazem, a blocker of L-type voltage-sensitive Ca2+ channels. The treatment of fura-2-loaded C6 glioma cells with TS-B-VIa (2-5 microM) led to an increase in the intracellular free Ca2+ concentration ([Ca2+]i) in a concentration-dependent manner but the stimulatory effects of TS-B-VIa on [Ca2+]i were only slightly observed in Ca(2+)-free medium, indicating that TS-B-VIa causes Ca2+ influx from the external medium into the C6 cells. The TS-B-VIa-induced increase in [Ca2+]i in the C6 cells was not antagonized by diltiazem and by SK&F 96365, a novel blocker of receptor-mediated Ca2+ entry. High K+ increased neither [Ca2+]1 in the C6 cells nor Mn2+ influx into the cells, while TS-B-VIa increased Mn2+ influx. Also in other non-excitable cells, bovine platelets, similar results were obtained. These results strongly suggest that the mechanism of Ca2+ influx by TS-B-VIa at the lower concentrations is distinct from the event of Ca2+ influx through receptor-operated or L-type voltage-sensitive Ca2+ channels in both excitable cells (the chrornaffin cells) and non-excitable cells (the C6 cells and the platelets) and that TS-B-VIa per se may form Ca(2+)-permeable ion channels in biological membranes. On the other hand, the peptide at the higher concentrations seems to damage cell membranes.

Fungal metabolites. XXI. Characteristics of low energy collision induced dissociation of [M + 2H]2+, [M + H + Na]2+ and [M + 2Na]2+ of peptaibols using electrospray ionization mass spectrometry

The mass spectral characteristics of selected peptaibols were investigated using electrospray ionization in conjunction with low-energy collision-induced dissociation (CID). Protonated and sodiated molecular species were selected as precursor ions and the resulting CID spectra are discussed with respect to fragmentation characteristics related to the structures of peptaibols. The CID spectra of peptaibols with acetylated N-terminus and with the sub-sequences of Aib-Pro were similar. The CID spectra of [M + 2Na]2+ provided structural information more than those of [M + 2H]2+ and [M + H + Na]2+. The CID of [M + 2Na]2+ can be used to deduce complete sequence information for peptaibols.

Expression of CD44 variant exons 8-10 in gastric cancer

The expression of CD44 variant containing variant exons 8-10 product (CD44v8-10) was studied by western blot analysis and immunohistochemistry in gastric cancers using a monoclonal antibody, 44-1V. On western blots, a single band of 130 kD was recognized in stomach cancer cell lines. CD44v8-10 expression, with reactivity localized in the cell membrane, was found in 65 (33.5%) of the 194 advanced gastric cancers. There was no correlation between CD44v8-10 immunoreactivity and serosal, lymphatic, or lymph node invasion. However, there was significant correlation with CD44v8-10 immunoreactivity and venous invasion. CD44v8-10-positive cancers were more frequently associated with hematogenous metastasis than those which were immunonegative. There was an inverse association between CD44v8-10 immunoreactivity and peritoneal dissemination, especially in diffuse type adenocarcinomas. These observations indicate that CD44v8-10 may play a role in the metastasis of gastric cancer.

Craniosynostosis with joint contractures, ear deformity, cleft palate, scoliosis, and other features

A case of craniosynostosis with joint contractures, ear deformity, cleft palate, scoliosis, and many other features is presented. The patient's skull was round with craniosynostosis of the coronal suture. The fingers were slender and long; the finger joints were contracted. Trismus was also present. Contracture of the temporomandibular joint was suspected. The helices were flat, antihelices were minimal, and the ears protruded. Furthermore, the facial and cranial features of this patient included mild hypertelorism, ocular proptosis, short pons nasi, flat radix nasi, mild retrognathia, and small oral fissure. In the oral cavity, a relatively wide cleft extended from the soft palate to the uvula. A frontal chest radiograph revealed a mild scoliosis. Differential diagnoses are discussed in reported syndromes with craniosynostosis.

Cloning of a guanosine-inosine kinase gene of Escherichia coli and characterization of the purified gene product

We attempted to clone an inosine kinase gene of Escherichia coli. A mutant strain which grows slowly with inosine as the sole purine source was used as a host for cloning. A cloned 2.8-kbp DNA fragment can accelerate the growth of the mutant with inosine. The fragment was sequenced, and one protein of 434 amino acids long was found. This protein was overexpressed. The overexpressed protein was purified and characterized. The enzyme had both inosine and guanosine kinase activity. The Vmaxs for guanosine and inosine were 2.9 and 4.9 mumol/min/mg of protein, respectively. The Kms for guanosine and inosine were 6.1 microM and 2.1 mM, respectively. This enzyme accepted ATP and dATP as a phosphate donor but not p-nitrophenyl phosphate. These results show clearly that this enzyme is not a phosphotransferase but a guanosine kinase having low (Vmax/Km) activity with inosine. The sequence of the gene we have cloned is almost identical to that of the gsk gene (K.W. Harlow, P. Nygaard, and B. Hove-Jensen, J. Bacteriol. 177:2236-2240, 1995).

Properties of trichosporin-B-VIa-induced catecholamine secretion from bovine adrenal chromaffin cells

Trichosporin (TS)-B-VIa, a peptide consisting of 19 amino acid residues and an amino alcohol, causes Ca(2+)-dependent secretion of catecholamines from bovine adrenal chromaffin cells. The TS-B-VIa-induced secretion was greater under alkaline conditions and at a temperature of 37 degrees C compared with that at 21 degrees or 30 degrees C. It was not observed when the peptide was eliminated from the incubation medium. These results strongly suggest that the stimulatory effect of TS-B-VIa on the secretion is reversible and dependent on the temperature and pH of the incubation medium.

Fungal metabolites. XX. Effect of proline residue on the structure of ion-channel-forming peptide, trichosporin B-VIa

The secondary structures of an ion-channel-forming icosapeptaibol, trichosporin B-VIa, and its Aib14-substituted derivative containing no Pro were investigated on the basis of CD and various NM experiments in methanol. Trichosporin B-VIa has a fully helical structure with a kink stabilized by a 1<--4 hydrogen-bond between the Leu12 CO and Val15 NH. The helical structure is composed of 3(10)-helix in the N-terminal first turn and the C-terminal moiety following Leu12, and alpha-helix in the middle region. In contrast, the Aib14 derivative predominantly has a straight alpha-helical structure except for a 3(10)-helix region in the N-terminal first turn.

Positive and negative cis-regulatory regions in the soybean glycinin promoter identified by quantitative transient gene expression

The 5' and 3' flanking regions of the soybean glycinin gene, Gy1, responsible for expression in seeds, were analyzed by quantitative transient expression assay. The construct containing the β-glucuronidase (uidA) reporter gene under the control of the 1.12 kb Gy1 promoter and 0.74 kb Gy1 terminator was introduced into immature soybean seeds and leaves by particle bombardment. To normalize the variability of introduction efficiency, a second reporter gene, firefly luciferase, was cobombarded as an internal standard, and relative activities (GUS/luciferase) were measured. There was a seed-specific β-glucuronidase (GUS) expression, as observed by X-Gluc staining. Compared with the nopaline synthase gene (nos) terminator, the Gy1 terminator enhanced the level of expression in immature seeds, indicating that the terminator region of the glycinin gene is involved in the activation of the gene expression in these seeds. To identify cis-regulatory elements in the glycinin gene upstream sequence, deleted derivatives of the promoter were fused to the luciferase reporter gene. The expression could be measured with a higher accuracy, and constructs were introduced with the internal reporter uidA gene into immature seeds. The results suggest the presence of a positive regulatory element in the -620 to --380 region of the Gy1 promoter. A deletion which eliminates the legumin box with its RY element led to increased relative activity, suggesting that this box is negatively regulating expression of the seed storage protein gene. Analysis of mutant promoters also suggest that the RY element involves negative regulation in seeds. This quantitative transient expression assay using particle bombardment provides a reliable system for the study of seed-specific gene expression in soybeans.

Local continuity of myocardial blood flow studied by monochromatic synchrotron radiation-excited x-ray fluorescence spectrometry

We have developed a monochromatic synchrotron radiation-excited system for two-dimensional mapping of x-ray fluorescence evoked from heavy element-loaded microspheres, which can evaluate myocardial blood flow in small contiguous regions with a small methodological error: 10.8 +/- 2.4% of the average of difference of the dual flow for 7- to 10-mg myocardial tissue (4 dogs). The fractal D value obtained from the slope of the log relative dispersion-log mass plot was 1.21 +/- 0.08 for a voxel size of 7 to 1260 mg (5 dogs) and that for a voxel size of 2.5 to 40 mg (1.12 +/- 0.06) was smaller than that for a voxel size of 40 to 1280 mg (1.25 +/- 0.14, P < .05, ANOVA, 4 dogs). The distance-correlation coefficient relation for paired myocardial regions was attenuated (correlation analysis), and the correlation coefficients between the original grouping and the two aggregates of the adjacent regions were dissociated (extended correlation analysis) under reduction of coronary perfusion pressure (6 dogs). Suppression of myocardial contraction with lidocaine (3 dogs) and vasodilation with adenosine partly improved the distance-correlation coefficient relation under reduced coronary perfusion pressure. Thus, an x-ray fluorescence system designed for precise flow measurement shows that the fractal nature of local flow distribution can be extended into regions smaller than previously reported, that in these regions the flow becomes more homogeneous, and that the self similarity and continuity of local flow are attenuated by the reduction of coronary perfusion pressure and improved by contractile suppression and coronary vasodilation.

Fungal metabolites. XIX. Structural elucidation of channel-forming peptides, trichorovins-I-XIV, from the fungus Trichoderma viride

Trichorovins (TV)-I-XIV are new antibiotic peptides obtained from conidia of the fungus Trichoderma viride. The peptide mixture of TVs was repeatedly fractionated by preparative HPLC until individual TVs showed a single peak on their analytical HPLC chromatograms. Nevertheless, FAB-MS or NMR indicated that each of TVs-I-XIV was composed of at least two components. We attempted to elucidate their structures within the fractions by electrospray ionization (ESI)-MS, FAB-MS, FAB-MS/MS and NMR. TVs generally have molecular weights of approximately 1100-1200 Da, and are characterized by an acetylated N-terminus, the presence of an aminoalcohol, e.g. leucinol, isoleucinol or valinol, at the C-terminus, and eleven residues including three alpha-aminoisobutyric acids in the molecule. Thus, it was determined that TVs belong to the class of peptaibols.

Relationships among the expression of epidermal growth factor receptor, proliferating cell nuclear antigen labeling index, and lymph node metastasis in gastric cancer

The expression of epidermal growth factor receptor (EGFR), epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha) and the labeling index of proliferating cell nuclear antigen (PCNA LI) were examined immunohistochemically in 288 gastric cancer patients, and the relationships between these results and the lymph node metastasis were studied. To investigate the relation between the expression of EGFR and PCNA LI, we divided the patients into the following three groups according to the immunohistochemical findings: group A, EGFR (+); group B, EGFR (-), and EGF(+) or TGF alpha(+); group C, EGFR(-), EGF(-) and TGF alpha(-). In the cancers invading submucosal or proper muscle layer, high-PCNA tumors (PCNA LI > or = 70) in both groups A and B had more frequent lymph node metastasis than in the intermediate-(40-69) and low- (< or = 39) PCNA tumors. In the cancers invading subserosal layer or further, the frequency of metastasis in group A was over 78% and was not related to the PCNA range. In group B, metastasis was more frequent in high- and intermediate-PCNA tumors (about 80%) than in low-PCNA tumors (44%). These results suggest that growth regulation by EGFR is related to lymph node metastasis in gastric cancer, and the higher the PCNA LI of cancer cells becomes, the more frequent the occurrence of lymph node metastasis.

Effect of lipophilicity of trichosporin-Bs on ion-channel formation and catecholamine-releasing activity

A series of peptaibols, trichosporin (TS) -Bs, induced voltage-activated conductance in lipid bilayer membranes and catecholamine secretion from bovine adrenal chromaffin cells. The order of activities is the same as that of the lipophilicity rank of TS-Bs derived from the reversed-phase HPLC capacity factors.

Fungal metabolites. XVIII. New membrane-modifying peptides, trichorozins I-IV, from the fungus Trichoderma harzianum

New membrane-modifying peptides, trichorozins I-IV, have been isolated from conidia of the fungus Trichoderma harzianum. Their amino acid sequences were clearly determined by spectrometric methods and, furthermore, they were synthesized by the solution-phase method. Trichorozins are a family of the class of peptaibols and are composed of 11 residues including an amino alcohol. Trichorozins exhibited voltage-dependent ion channel-like activity in lipid bilayers.

Allelic losses on chromosome band 11q13 in aldosterone-producing adrenal tumors

We examined loss of heterozygosity (LOH) in 14 aldosterone-producing adrenal tumors, with six linearly ordered restriction fragment length polymorphism (RFLP) markers that map within a 12-cM region containing the MEN1 locus on 11q13. Among 11 tumors that were informative for at least one marker, five showed LOH at one or more loci, and two distinct regions of deletion were identified. The proximal region overlapped with the location of the MEN1 locus previously predicted by linkage analyses in MEN1 families and the commonly deleted region in hyperparathyroid tumors. This suggests that one of the genes associated with development of aldosterone-producing adrenal tumors may coincide with the MEN1 locus, and that a second gene, distal to the MEN1 locus, may also play a role in the development of this type of tumor.