Extreme low pH, not Al3+ , is a key abiotic stressor for the extremophyte Carex angustisquama (Cyperaceae) in highly acidic solfatara fields.

Volcanic acidification creates extreme soil conditions, where rhizotoxicity from extremely low pH (2-3) and high Al3+ strongly inhibit plant growth. C. angustisquama is a dominant extremophyte in highly acidic solfatara fields, where no other vascular plants can survive. Here we investigated the key abiotic stressor determining survival of this extremophyte. Soil analyses and topographic surveys were conducted to examine the effects of low pH and Al3+ , two major abiotic stressors in acidic soils, on the occurrence of C. angustisquama in solfatara fields. Hydroponic culture experiments were also performed to test its growth responses to these stressors. In field surveys, the spatial distribution of soil pH was consistent with vegetation zonation within a solfatara field. In contrast, soil exchangeable Al content was overall low due to strong eluviation. Statistical analysis also supported the significant role of soil pH in determining the distribution of C. angustisquama in a solfatara field. Furthermore, hydroponic culture experiments revealed a higher tolerance of C. angustisquama to low pH than a sister species, especially in the range pH 2-3, corresponding to the pH values of the actual habitats of C. angustisquama. Conversely, no significant interspecific difference was detected in Al3+ tolerance, indicating that both species had high Al3+ tolerance. This study suggests that low pH is a critical abiotic stressor leading to formation of the extremophyte in highly acidic solfatara fields. In contrast, C. angustisquama displayed high tolerance to Al3+ toxicity, probably acquired prior to speciation.

The expression of prostaglandin E receptors EP2 and EP4 and their different regulation by lipopolysaccharide in C3H/HeN peritoneal macrophages.

The expression and regulation of the PGE receptors, EP(2) and EP(4), both of which are coupled to the stimulation of adenylate cyclase, were examined in peritoneal resident macrophages from C3H/HeN mice. mRNA expression of EP(4) but not EP(2) was found in nonstimulated cells, but the latter was induced by medium change alone, and this induction was augmented by LPS. mRNA expression of EP(4) was down-regulated by LPS but not by medium change. PGE(2) increased the cAMP content of both LPS-treated and nontreated cells. ONO-604, an EP(4) agonist, also increased cAMP content in nonstimulated cells and in cells treated with LPS for 3 h, but not for 6 h. Butaprost, an EP(2) agonist, was effective only in the cells treated with LPS for 6 h. The inhibitory effects of ONO-604 on TNF-alpha and IL-12 production were equipotent with PGE(2) at any time point, but the inhibitory effects of butaprost were only seen from 14 h after stimulation. PGE(2) or dibutyryl cAMP alone, but not butaprost, reduced EP(4) expression, and indomethacin reversed the LPS-induced down-regulation of EP(4), indicating that the down-regulation of EP(4) is mediated by LPS-induced PG synthesis and EP(4) activation. Indeed, when we used C3H/HeJ (LPS-hyporesponsive) macrophages, such reduction in EP(4) expression was found in the cells treated with PGE(2) alone, but not in LPS-treated cells. In contrast, up-regulation of EP(2) expression was again observed in LPS-treated C3H/HeJ macrophages. These results suggest that EP(4) is involved mainly in the inhibition of cytokine release, and that the gene expression of EP(2) and EP(4) is differentially regulated during macrophage activation.

[A relationship between a psychosomatic and a skin condition in patients with atopic dermatitis].

Atopic dermatitis (AD) has been clinically well-known to be frequently exacerbated by some psychosomatic stress. In this study, we examined a relationship between a psychosomatic and a skin condition in patients with AD. Visual analogue scale (VAS) for the grade of general physical condition, mental stress and others were reported daily for themselves, while skin physiological parameters, resident skin bacteria and a psychological questionnaire (POMS) were measured every 2 weeks. It was observed that tense-anxious and depressive scores of POMS tended to correlate with skin conductance, a skin clinical score and a number of total skin bacteria and others. These results suggest that changes of psychosomatic condition reciprocally correlate with the exacerbation and improvement of skin symptom in patients with AD.

Isolation and characterization of the 5'-upstream and untranslated regions of the mouse type II iodothyronine deiodinase gene.

The type II iodothyronine deiodinase (D2) catalyzes the 5'-deiodination of thyroxine to yield the biologically active form, 3,3',5,-tri-iodothyronine, and is a member of the selenoproteins. We isolated a 17.5 kb mouse genomic clone containing the entire coding and 5'-untranslated regions of the D2 gene (mdio2). We also isolated the entire 5'-UTR of the mouse D2 cDNA, which was 753 bp in length and contained five ATG codons. An additional 258 bp ORF from the fourth ATG codon was found in the same reading frame as the coding region reported previously, and this additional ORF contained a TGA codon, which could encode selenocysteine. The proximal promoter of mdio2 contained a TATA box and several potential transcription factor-binding sequences, including CRE, C/EBP and GATA binding sites. The 1.3 kb 5'-upstream region exhibited a promoter activity by reporter assay using Mm5MT and JAR cells, which have a D2 transcript, but not HepG2 cells that have no detectable level of D2 transcript.

Characterization of a novel polycystic kidney rat model with accompanying polycystic liver.

A polycystic kidney rat model is being established from a Crj:CD (SD) rat strain. Unlike existing animal models of polycystic kidney disease, this mutant rat has a completely polycystic liver. Mating experiments revealed that the phenotype is controlled by an autosomal recessive gene. We propose that this gene be tentatively called the "rpc" gene.

Genomic organization, chromosomal mapping and promoter analysis of the mouse selenocysteine tRNA gene transcription-activating factor (mStaf) gene.

mStaf is a zinc-finger protein that activates the transcription of the mouse selenocysteine tRNA gene. The mStaf gene is approx. 35 kb long and split into 16 exons. All exon-intron junction sequences conform to the GT/AG rule. The transcription start site is located 83 bp upstream of the initiation codon. Chromosomal mapping localized the gene to mouse chromosome 7, region E3-F1. Sequence analysis of the proximal promoter region revealed several potential regulatory elements; these include the recognition elements of Sp1, Nkx, CP2, E2A, SIF (SIS-inducible factor), TFII-I and cAMP-responsive element (CRE), but no TATA sequences. Transfection experiments demonstrated that the 5'-flanking region (-1894 to +37) of the mStaf gene drives transcription in mouse NMuMG cells and that a construct containing a fragment from -387 to +37 showed the highest transcriptional activity. Deletion and mutation experiments suggested that four Sp1 sites played an important role for the basal promoter activity. Furthermore, electrophoretic mobility-shift assays demonstrated that Sp3 but not other Sp (specificity protein) family members binds to three of the Sp1 sites. Our present study suggests that Sp3 is involved in the basal transcriptional activation of the mStaf gene.

Characterization of the LPS-stimulated expression of EP2 and EP4 prostaglandin E receptors in mouse macrophage-like cell line, J774.1.

The expression of prostaglandin (PG) E receptor subtypes were characterized in J774.1, a mouse macrophage-like cell line. EP2- and EP4-mRNAs were found to be expressed. The expression of EP2 mRNA increased by the addition of lipopolysaccharide (LPS) in a dose-dependent manner. EP2 mRNA rapidly increased by more than 5-fold of the control level at 1 h, and decreased after 4 h. EP4 mRNA increased by only 2-fold of the control at 2 h. Gamma interferon inhibited both basal and LPS-induced expression of EP2 mRNA but did not affect the expression level of EP4 mRNA. When tumor necrosis factor-alpha (TNF-alpha) accumulation was measured after the treatment ofthe cells with LPS for 90 min, PGE2 was found to inhibit this accumulation, but butaprost, an EP2-selective agonist, did not. When TNF-alpha release was measured after the treatment of the cells with LPS for 8 h, accumulation was inhibited by butaprost as well as PGE2. These results indicated that the inhibitory effects of PGE2 on TNF-alpha production are mediated by EP2 and EP4 in macrophages, and that expression regulation of EP2 and EP4 in macrophages is quite different.

Impaired febrile response in mice lacking the prostaglandin E receptor subtype EP3.

Fever, a hallmark of disease, is elicited by exogenous pyrogens, that is, cellular components, such as lipopolysaccharide (LPS), of infectious organisms, as well as by non-infectious inflammatory insults. Both stimulate the production of cytokines, such as interleukin (IL)-1beta, that act on the brain as endogenous pyrogens. Fever can be suppressed by aspirin-like anti-inflammatory drugs. As these drugs share the ability to inhibit prostaglandin biosynthesis, it is thought that a prostaglandin is important in fever generation. Prostaglandin E2 (PGE2) may be a neural mediator of fever, but this has been much debated. PGE2 acts by interacting with four subtypes of PGE receptor, the EP1, EP2, EP3 and EP4 receptors. Here we generate mice lacking each of these receptors by homologous recombination. Only mice lacking the EP3 receptor fail to show a febrile response to PGE2 and to either IL-1beta or LPS. Our results establish that PGE2 mediates fever generation in response to both exogenous and endogenous pyrogens by acting at the EP3 receptor.

Structure-cytotoxic activity relationship for the toad poison bufadienolides.

The toad poison bufadienolides including natural and derivatized compounds were tested for their cytotoxic effects on primary liver carcinoma cells PLC/PRF/5 and their structure-cytotoxic activity relationships were studied. For this study, a ligand-binding model was developed by using a pharmacophore mapping program, Distance Comparisons (DISCO). The structural features that are common to the 3D structures of active bufadienolides were identified to provide approach to a 3D QSAR method by using Comparative Molecular Field Analysis (CoMFA) study and to correlate the steric and electrostatic fields of the molecules to their activities. A valuable model which enables prediction of their activities was obtained from the CoMFA analysis, which may be employed for the drug designs of new bufadienolide analogues.

Characterization of the gene for the mouse prostaglandin E receptor subtype EP2: tissue-specific initiation of transcription in the macrophage and the uterus.

Genomic DNA clones for the mouse prostaglandin (PG) E receptor subtype EP2 were isolated and characterized. The mouse EP2 gene is composed of 2 exons and 1 intron, and spans 16 kb. The intron which is approx. 12 kb in length is located at the end of the sixth transmembrane domain, as with other prostanoid receptor genes. Based on this structure, transcripts were analysed in endotoxin-treated macrophages and pseudopregnant uteri, in which abundant expression of EP2 mRNA was observed. Sequence analysis of cDNA clones from these origins and Northern hybridization of these RNAs revealed that the uterine EP2 mRNA (U-type) has a longer 5'-untranslated region than the macrophage EP2 transcript (M-type). The major transcription initiation sites for M-type and U-type EP2 are located 124 and 769 bp upstream of the translation start site, respectively. The M-type was expressed in various tissues, whereas the U-type was found only in the uterus. The 2 kb segment containing the immediate 5'-flanking and 5'-noncoding regions contain three consensus sequences for the NF-IL6 binding site, one consensus sequence for the NF-kappaB binding site, four AP-2 consensus sequences, one AP-4 consensus sequence, one potential cAMP response element, and one potential progesterone response element. These results suggest that EP2 gene expression in the macrophage and uterus is under the control of distinct mechanisms involving alternative promoters.

Failure of parturition in mice lacking the prostaglandin F receptor.

Mice lacking the gene encoding the receptor for prostaglandin F2alpha (FP) developed normally but were unable to deliver normal fetuses at term. Although these FP-deficient mice showed no abnormality in the estrous cycle, ovulation, fertilization, or implantation, they did not respond to exogenous oxytocin because of the lack of induction of oxytocin receptor (a proposed triggering event in parturition), and they did not show the normal decline of serum progesterone concentrations that precedes parturition. Ovariectomy at day 19 of pregnancy restored induction of the oxytocin receptor and permitted successful delivery in the FP-deficient mice. These results indicate that parturition is initiated when prostaglandin F2alpha interacts with FP in ovarian luteal cells of the pregnant mice to induce luteolysis.

Distribution of prostaglandin E receptors in the rat gastrointestinal tract.

AIMS: In order to study the role of prostaglandin in the regulation of the gastrointestinal functions, gene expression of prostaglandin receptors along the rat gastrointestinal tracts were investigated. METHODS: Rats were used for the study. The combination of counterflow elutriation separation of mucosal cells and Northern blot analysis was used to detect the gene expression of prostaglandin receptors in gastrointestinal tracts. RESULTS: In small intestine and colon, prostaglandin E2 EP1 and EP3 receptor mRNAs were mainly localized in the deeper intestinal wall containing muscle layers. EP4 receptor gene expression, on the other hand, was detected in the intestinal mucosal layer. In the stomach, EP1 mRNA was detected in gastric muscle layers, whereas EP3 and EP4 receptor gene expression was mainly present in the gastric mucosal layer containing epithelial cells. In gastric epithelial cells, parietal cells were found to have both EP3 and EP4 receptors. At lower concentrations, prostaglandin E2 inhibited gastric acid secretion by parietal cells probably through EP4 receptors. At higher concentrations, however, it stimulated it. On the other hand, mucous cells possessed only EP4 receptor mRNA. CONCLUSIONS: Thus, it is suggested that prostaglandin E2 modulates gastrointestinal functions through at least three different prostaglandin receptors (EP1, EP3, and EP4), each of which has a distinct contribution in the gastrointestinal tract.

Cellular localization of mRNAs for prostaglandin E receptor subtypes in mouse gastrointestinal tract.

Regional and cellular distribution of mRNAs for prostaglandin E (PGE) receptor subtypes was investigated in the mouse gastrointestinal tract by in situ hybridization. Strong signals for EP1 transcripts were detected in cells of the muscularis mucosae layer, especially in the body of the stomach. Intense signals for EP3 transcripts were detected in neurons of the myenteric ganglia throughout the tract. Moderate EP3 mRNA expression was also observed in fundic gland epithelial cells, except for surface mucous cells in the stomach. Expression of EP4 mRNA was moderate in surface epithelial cells of the corpus and in glands from the surface to the base of the antrum. Strong EP4 signals were observed in the epithelium in the duodenum, jejunum, and ileum. In the ileum, signals were only observed in the upper part of the villi. However, no or weak signals for EP2 transcripts were detected. These findings suggest that PGE2 modulates various gastric or intestinal functions via at least three different PGE receptors.

'Distinct cellular localization' of the messenger ribonucleic acid for prostaglandin E receptor subtypes in the mouse uterus during pseudopregnancy.

As an initial step to clarify the mechanisms of various uterine actions of PGE2, expression patterns of the messenger RNAs (mRNAs) for four subtypes of PGE receptors, EP1, EP2, EP3, and EP4, were investigated in the mouse uterus during pseudopregnancy. Relative expression levels were investigated by Northern blot analysis of mRNA levels in uteri obtained on days 0, 1, 3, 5, 7, and 9 of pseudopregnancy (day 0 = 48 h after PMSG injection), and cellular localization was determined by in situ hybridization in uteri obtained on days 0 and 5. EP2 mRNA was specifically expressed on day 5, and its expression was confined to the luminal epithelium. On the other hand, the level of the EP3 mRNA expression progressively increased until day 5. Cell populations expressing the EP3 mRNA were confined to the longitudinal smooth muscle on day 0, but they changed to the circular smooth muscle on day 5. The expression level of EP4 mRNA was low on days 0 and 1, but it became high on days 3 and 5. On day 0, EP4 mRNA was localized to the luminal epithelium. On day 5, diffuse, but significant, EP4 expression was observed over the endometrial stroma and epithelium. No EP1 mRNA signals were observed. Transient expression of EP2 on day 5 of pseudopregnancy in the luminal epithelium suggests its involvement in blastocyst implantation signaling. EP4 in the endometrial stroma is suggested to be involved in decidual transformation of the stromal cells, whereas EP3 in the myometrium is believed to be involved in regulation of myometrial activity.

The mouse prostaglandin E receptor EP2 subtype: cloning, expression, and northern blot analysis.

A functional cDNA clone for the mouse prostaglandin (PG) E receptor EP2 subtype was isolated from a mouse cDNA library. The mouse EP2 receptor consists of 362 amino acid residues with seven putative transmembrane domains. [3H]PGE2 bound specifically to the membrane of Chinese hamster ovary cells stably expressing the cloned receptor. This binding was displaced by unlabeled prostanoids in the order of PGE2 = PGE1 >> iloprost, a stable PGI2 agonist > PGF2 alpha > PGD2. Binding was also inhibited by butaprost (an EP2 agonist) and to a lesser extent by M&B 28767 (an EP3 agonist), but not by sulprostone (an EP1 and EP3 agonist) or SC-19220 (an EP1 antagonist). PGE2 and butaprost increased the cAMP level in the Chinese hamster ovary cells in a concentration-dependent manner. Northern blot analysis revealed that EP2 mRNA is expressed most abundantly in the uterus, followed by the spleen, lung, thymus, ileum, liver, and stomach.

Inhibitory effect of natural carotenoids on Epstein-Barr virus activation activity of a tumor promoter in Raji cells. A screening study for anti-tumor promoters.

As a screening study for anti-tumor promoters, 51 carotenoids with diverse structures were examined for their inhibitory effects on the Epstein-Barr virus activation activity of 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. The results showed that most of the carotenoids exhibited inhibitory activity, and in general, no cytotoxicity on Raji cells was observed in the assay. Among the carotenoids, beta-cryptoxanthin, lutein, and lactucaxanthin showed the strongest inhibitory activity, superior to the well known anti-tumor promoter, beta-carotene. Heteroxanthin, peridinin, and halocynthiaxanthin showed cytotoxicity at the high concentration (1000 molar ratio per TPA), but indicated a strong inhibitory effect at the lower concentrations, which were only weakly toxic (500 and 100 molar ratios). Based on these results, the essential moiety for the activity of carotenoids was considered to be the 3-hydroxy-epsilon-end group.

Cloning and expression of a cDNA for the human prostacyclin receptor.

A functional cDNA for the human prostacyclin receptor was isolated from a cDNA library of CMK cells, a human megakaryocytic leukaemia cell line. The cDNA encodes a protein consisting of 386 amino acid residues with seven putative transmembrane domains and a deduced molecular weight of 40,956. [3H]Iloprost specifically bound to the membrane of CHO cells stably expressing the cDNA with a Kd of 3.3 nM. This binding was displaced by unlabelled prostanoids in the order of iloprost = cicaprost >> carbacyclin > prostaglandin E1 (PGE1) > STA2. PGE2, PGD2 and PGF 2 alpha did not inhibit it. Iloprost in a concentration-dependent manner increased the cAMP level and generated inositol trisphosphate in these cells, indicating that this human receptor can couple to multiple signal transduction pathways.

Cloning and expression of a cDNA for mouse prostaglandin F receptor.

A functional cDNA clone for mouse prostaglandin (PG) F receptor was isolated from a mouse cDNA library using polymerase chain reaction based on the sequence of cloned prostanoid receptors, and cross-hybridization screening. The mouse PGF receptor consists of 366 amino acid residues with putative seven transmembrane domains. The sequence revealed the highest homology to the EP1 subtype of PGE receptor and thromboxane (TX) A2 receptor. Ligand binding studies using membranes of COS cells transfected with the cDNA revealed specific [3H]PGF2 alpha binding. The binding was displaced with unlabeled PGs in the order of PGF2 alpha = 9 alpha, 11 beta PGF2 > PGF 1 alpha > PGD2 > STA2 (a stable TXA2 agonist) > PGE2 > iloprost (a stable PGI2 agonist). PGF2 alpha increased inositol trisphosphate formation in a concentration-dependent manner in COS cells expressing PGF receptor. RNA blot and in situ hybridization analyses demonstrated that the PGF receptor transcripts are abundantly expressed in luteal cells of corpus luteum and in a lesser amount in kidney, heart, stomach, and lung.

[Comparison of the amounts of hCG and PMSG to induce ovulation in 50% of the animals, mice, Syrian hamsters and rats].

On the day of diestrus, female mice, syrian hamsters and rats, showing regular 4-day estrous cycles, were injected with hCG or PMSG and were inspected for the presence of ovulation the following day. The dose level expected to cause an effect in 50% of the animals (ED50) was calculated using the Van der Waerden method. When hCG was injected into i. v., i. p. and s. c., the ED50 values per animal and per body weight (kg) in parenthesis were as follows; 0.2 (7.7), 0.3 (11.5) and 0.7 (26.9) I. U. for mice, 1.0 (9.5), 1.8 (17.1) and 2.6 (24.8) I. U. for syrian hamsters and 1.3 (4.6), 3.5 (12.3) and 7.5 (26.3) I. U. for rats, respectively. In PMSG study, the ED50 values per animal and per body weight (kg) in parenthesis were as follows: i. v., 0.8 (30.8); i. p., 2.0 (76.9); s. c., 2.8 (107.7) I. U. for mice, i. v., 3.6 (34.3); i. p., 8.0 (76.2); s. c., 13.2 (125.7) I. U. for syrian hamsters and i. v., 6.0 (76.8); i. p., 20.8 (73.0); s. c., 76.8 (269.5) I. U. for rats, respectively. From these results, the intravenous ED50 value was lower than other routes in three rodents with hCG or PMSG. In all injection routes, the ED50 value for mouse was lower than others. However, there were not significant differences in the ED50 values per body weight (kg) among three rodents. In particular, subcutaneous ED50 of hCG and intraperitoneal ED50 of PMSG were almost same values among three rodents, respectively. Given that the ED50 value per body weight (kg) in one of three rodents is determined, its value may be possible to be extrapolated to remaining two rodents.

Studies on the activity of L-threo-3,4-dihydroxyphenylserine (L-DOPS) as a catecholamine precursor in the brain. Comparison with that of L-dopa.

L-Threo-3,4-dihydroxyphenylserine (L-DOPS) was compared with L-3,4-dihydroxyphenylalanine (L-DOPA) with respect to their activities as central amine precursors. The apparent Km value (the substrate affinity) of L-DOPS for aromatic L-amino acid decarboxylase was nearly equal to that of L-DOPA, whereas the vmax value (the rate of decarboxylation) of L-DOPS was much smaller than that of L-DOPA, the penetration of L-DOPS into the brain through the blood-brain barrier was found to be smaller (about one-fourth) than that of L-DOPA but, for an amine precursor, it was still substantial. Unlike L-DOPA, L-DOPS did not cause a marked accumulation of norepinephrine (NE), the corresponding catecholamine in the brain, but nialamide, a monoamine oxidase inhibitor significantly enhanced the L-DOPS-induced rise of NE. Moreover, the brain concentration of 3-methoxy-4-hydroxy-phenylethyleneglycol (MHPG), the principal end metabolite of NE, was increased markedly by L-DOPS. These results suggest that L-DOPS may act as an NE precursor in the brain and activate NE neurons by increasing the turnover rate of NE.