Active site residues and amino acid specificity of the ubiquitin carrier protein-binding RING-H2 finger domain

EL5 is a rice ubiquitin-protein isopeptide ligase (E3) containing a RING-H2 finger domain that interacts with Oryza sativa (Os) UBC5b, a rice ubiquitin carrier protein. We introduced point mutations into the EL5 RING-H2 finger so that residues that functionally interact with OsUBC5b could be identified when assayed for ubiquitination activity in vitro. The residue positions were selected based on the results of an EL5 RING-H2 finger/OsUBC5b NMR titration experiment. These RING-H2 finger residues form or are adjacent to a shallow groove that is recognized by OsUBC5b. The E3 activity of EL5 is shown to be dependent on a Trp located at the center of the groove. We classified rice RING fingers according to the type of metal-chelating motif, i.e. RING-H2 or RING-HC, and according to the presence or absence of a conserved EL5-like Trp. We discuss the probable relationship between E3 activity and the conserved Trp.

Involvement of the basic helix-loop-helix transcription factor RERJ1 in wounding and drought stress responses in rice plants

The jasmonic acid (JA)-responsive gene RERJ1 isolated from suspension-cultured rice cells encodes a transcription factor with a basic helix-loop-helix motif. In this study, we found that RERJ1 is also expressed in rice plants in response to JA, and that its expression in rice leaves is up-regulated by exposure to wounding and drought stress. It is also suggested that JA but not abscisic acid is involved in the up-regulation of RERJ1 expression caused by wounding and drought stress.

Dissection of the Phosphorylation of Rice DELLA Protein, SLENDER RICE1

DELLA proteins are repressors of gibberellin signaling in plants. Our previous studies have indicated that gibberellin signaling is derepressed by SCF(GID2)-mediated proteolysis of the DELLA protein, SLENDER RICE1 (SLR1), in rice. In addition, the gibberellin-dependent increase of phosphorylated SLR1 in the loss-of-function gid2 mutant suggests that the SCF(GID2)-mediated degradation of SLR1 might be initiated by gibberellin-dependent phosphorylation. To confirm the role of phosphorylation of SLR1 in its gibberellin-dependent degradation, we revealed that SLR1 is phosphorylated on an N-terminal serine residue(s) within the DELLA/TVHYNP and polyS/T/V domain. However, gibberellin-induced phosphorylation in these regions was not observed in the gid2 mutant following the constitutive expression of SLR1 under the control of the rice actin1 promoter. Treatment with gibberellin induced both the phosphorylated and non-phosphorylated forms of SLR1 with similar induction kinetics in gid2 mutant cells. Both the phosphorylated and non-phosphorylated SLR1 proteins were degraded by gibberellin treatment with a similar half-life in the rice callus cells, and both proteins interacted with recombinant glutathione S-transferase (GST)-GID2. These results demonstrate that the phosphorylation of SLR1 is independent of its degradation and is dispensable for the interaction of SLR1 with the GID2/F-box protein.

Elicitor-induced Activation of Phospholipases Plays an Important Role for the Induction of Defense Responses in Suspension-cultured Rice Cells

Biphasic generation of reactive oxygen species (ROS) induced by N-acetylchitooligosaccharide elicitor in rice cells was associated with the activation of phopholipase C (PLC) and phospholipase D (PLD). The activation of both enzymes was observed for the first phase of ROS generation, but only the activation of PLD was evident for the second response. Activation of PLD was associated with its recruitment to the membrane. Enzymatic products of these phospholipases, diacylglycerol (DG) and phosphatidic acid (PA), could induce ROS generation by themselves. Moreover, the addition of these lipids compensated the inhibition of the second phase of ROS generation by cycloheximide, indicating the involvement of the synthesis of PLD or related proteins in the second phase of ROS generation. DG and PA also induced the expression of elicitor-responsive genes in the absence of the elicitor. They could not induce phytoalexin biosynthesis by themselves but greatly enhanced the elicitor-induced phytoalexin accumulation. Further, the inhibition of PLD by 1-butanol inhibited the elicitor-induced phytoalexin accumulation, indicating the involvement of PLD and its reaction product, PA, in the induction of phytoalexin biosynthesis. These results indicated the importance of phospholipid signaling, especially by PLD and its product PA, in plant defense responses.

Characterization and cDNA cloning of monomeric lectins that correspond to the B-Chain of a type 2 ribosome-inactivating protein from the bark of Japanese elderberry (Sambucus sieboldiana)

Two monomeric lectins, SSA-b-3 and SSA-b-4, were purified from the bark tissue of Japanese elderberry, Sambucus sieboldiana. SDS-PAGE of the purified lectins showed the presence of single bands of 35 and 33 kDa for SSA-b-3 and SSA-b-4, respectively, irrespective of the presence of reducing agent. MS analysis as well as gel filtration of these lectins indicated that they exist mostly as monomeric lectins. Analysis of the N-terminal amino acid sequences of SSA-b-3 and SSA-b-4 yielded an identical sequence, indicating their close structural relationship. Four cDNA clones with extensive homology were obtained from the bark cDNA library and indicated to encode SSA-b-3 or SSA-b-4 from the comparison with the N-terminal sequences of these lectins. These clones were classified into two groups, three for SSA-b-3 and one for SSA-b-4, based on the predicted isoelectric points. The amino acid sequences of the encoded polypeptides were almost identical with the B-chain of a type 2 ribosome-inactivating protein from the same bark tissue, sieboldin-b, except for the absence of a small peptide containing a cystein residue, which is critical for the heteromeric dimerization with an A-subunit. Carbohydrate binding specificity and biological activity of these lectins are also reported.

RERJ1, a jasmonic acid-responsive gene from rice, encodes a basic helix-loop-helix protein

Differential screening of a cDNA library constructed using poly(A)(+) RNA from suspension-cultured rice cells treated with jasmonic acid (JA) for 1/2h yielded a cDNA of a gene tentatively named RERJ1 that is upregulated in response to exogenous JA. Northern blot analysis indicated that the RERJ1 mRNA levels peaked at 1/2-1h after the addition of jasmonic acid and then decreased gradually. RERJ1 encodes a transcriptional regulator with a basic helix-loop-helix motif. The phenotypes of transgenic rice plants overexpressing sense or antisense RERJ1 mRNA demonstrated that RERJ1 is involved in the growth inhibition of rice shoots caused by JA. Other biological functions of RERJ1 are discussed from an evolutionary standpoint.

Crystallization and preliminary X-ray analysis of the Streptomyces olivaceoviridis NgcE binding protein of the ABC transporter for N-acetylglucosamine

The NgcE protein binds N-acetylglucosamine (GIcNAc) as well asN,N'-diacetylchitobiose and is a component of the ABC transporter Ngc for GIcNAc uptake in Streptomyces olivaceoviridis. After cloning the corresponding gene in an Escherichia coli host, the NgcE protein was overproduced in a soluble form within the cytoplasm and purified to homogeneity by four consecutive chromatographic processes. Crystals of NgcE that grew in the presence of 1 mM GlcNAc,20%(w/v) PEG MME 2000 and 100 mM Tris-HCI pH 8.5 had a plate-like shape and belonged to either space group P21212 (unit-cell parameters a = 59.9, b = 153.0, c = 41.7 A) or P212121 (a = 58.1, b = 96.3, c = 151.7 A). The former crystals diffracted to 1.8 A resolution andthe latter to 2.2 A. Selenomethionine-containing crystals were generated under the same conditions and belonged to space group P212121 with unit-cell parameters a = 58.4, b = 96.6, c = 152.5 A, and diffracted to 2.0 A resolution.

Stemar-13-ene synthase, a diterpene cyclase involved in the biosynthesis of the phytoalexin oryzalexin S in rice

In suspension-cultured rice cells, diterpenoid phytoalexins are produced in response to exogenously applied elicitors. We isolated a cDNA encoding a diterpene cyclase, OsDTC2, from suspension-cultured rice cells treated with a chitin elicitor. The OsDTC2 cDNA was overexpressed in Escherichia coli as a fusion protein with glutathione S-transferase, and the recombinant OsDTC2 was indicated to function as stemar-13-ene synthase that converted syn-copalyl diphosphate to stemar-13-ene, a putative diterpene hydrocarbon precursor of the phytoalexin oryzalexin S. The level of OsDTC2 mRNA in suspension-cultured rice cells began to increase 3 h after addition of the elicitor and reached the maximum after 8 h. The expression of OsDTC2 was also induced in UV-irradiated rice leaves. In addition, we indicated that stemar-13-ene accumulated in the chitin-elicited suspension-cultured rice cells and the UV-irradiated rice leaves.

Activation of phospholipase D induced by hydrogen peroxide in suspension-cultured rice cells

Hydrogen peroxide (H2O2) (10-100 microM) induced rapid and transient accumulation of phosphatidic acid (PA) in suspension-cultured rice cells. When phospholipase activity in the cellular extract fraction prepared from rice cells treated with H2O2 was assayed in the presence of 1-butanol (0.1%), rapid and transient phosphatidylbutanol (PtdBut) formation was observed. Thus, the H2O2-activated phospholipase was concluded to be phospholipase D (PLD). Furthermore, H2O2 directly induced in vitro PLD activation in the cytosolic fraction without H2O2 treatment. In vitro and in vivo activation of PLD were completely suppressed in the presence of lavendustin A (0.05 mM), a potent inhibitor of protein tyrosine kinase. Phytoalexin biosynthesis induced by N-acetylchitooligosaccharide elicitor was enhanced in the presence of H2O2 (10-100 microM), whereas it was suppressed in the presence of tiron, a potent scavenger of O2-, 1-butanol (0.1%) and lavendustin A (0.05 mM). These results indicate that H2O2-inducible PLD activation enhances signal transduction leading to phytoalexin biosynthesis in rice cells.

Two rice GRAS family genes responsive to N -acetylchitooligosaccharide elicitor are induced by phytoactive gibberellins: evidence for cross-talk between elicitor and gibberellin signaling in rice cells

In this study, we present data showing that two members of the GRAS family of genes from rice, CIGR1 and CIGR2 (chitin-inducible gibberellin-responsive), inducible by the potent elicitor N -acetylchitooligosaccharide (GN), are rapidly induced by exogenous gibberellins. The pattern of mRNA accumulation was dependent on the dose and biological activity of the gibberellins, suggesting that the induction of the genes by gibberellin is mediated by a biological receptor capable of specific recognition and signal transduction upon perception of the phytoactive compounds. Further pharmacological analysis revealed that the CIGR1 and CIGR2 mRNA accumulation by treatment with gibberellin is dependent upon protein phosphorylation/dephosphorylation events. In rice calli derived from slender rice 1, a constitutive gibberellin-responsive mutant, or d1, a mutant deficient in the alpha -subunit of the heterotrimeric G-protein, CIGR1 and CIGR2 were induced by a GN elicitor, yet not by gibberellin. Neither gibberellin nor GN showed related activities in defense or development, respectively. These results strongly suggested that the signal transduction cascade from gibberellin is independent of that from GN, and further implied that CIGR1 and CIGR2 have dual, distinct roles in defense and development.

Rice gene expression in response to N-acetylchitooligosaccharide elicitor: comprehensive analysis by DNA microarray with randomly selected ESTs

N-acetylchitooligosaccharides are potent elicitors to suspension-cultured rice cells, inducing a set of defense reactions. Expression of defense-related genes is considered to play an important role in defense reactions, and we employed microarray analysis of 8987 randomly selected expressed sequence tags to analyze the changes in gene expression caused by N-acetylchitooctaose. In this experiment, 166 genes were significantly induced and 93 genes were repressed. RNA gel blot analysis of 16 of these genes confirmed the microarray results. Of the 259 ESTs identified as responsive to N-acetylchytooctaose, 18 genes are related to signal transduction, including five calcium-dependent protein kinases (CDPKs). Among these, three novel CDPKs responsive to N-acetylchitooctaose were isolated.

High precision NMR structure and function of the RING-H2 finger domain of EL5, a rice protein whose expression is increased upon exposure to pathogen-derived oligosaccharides

EL5, a RING-H2 finger protein, is rapidly induced by N-acetylchitooligosaccharides in rice cell. We expressed the EL5 RING-H2 finger domain in Escherichia coli and determined its structure in solution by NMR spectroscopy. The EL5 RING-H2 finger domain consists of two-stranded beta-sheets (beta1, Ala(147)-Phe(149); beta2, Gly(156)-His(158)), one alpha-helix (Cys(161)-Leu(166)), and two large N- and C-terminal loops. It is stabilized by two tetrahedrally coordinated zinc ions. This structure is similar to that of other RING finger domains of proteins of known function. From structural analogies, we inferred that the EL5 RING-H2 finger is a binding domain for ubiquitin-conjugating enzyme (E2). The binding site is probably formed by solvent-exposed hydrophobic residues of the N- and C-terminal loops and the alpha-helix. We demonstrated that the fusion protein with EL5-(96-181) and maltose-binding protein (MBP) was polyubiquitinated by incubation with ubiquitin, ubiquitin-activating enzyme (E1), and a rice E2 protein, OsUBC5b. This supported the idea that the EL5 RING finger domain is essential for ubiquitin-ligase activity of EL5. By NMR titration experiments, we identified residues that are critical for the interaction between the EL5 RING-H2 finger and OsUBC5b. We conclude that the RING-H2 finger domain of EL5 is the E2 binding site of EL5.

Induction of myrosinase gene expression and myrosinase activity in radish hypocotyls by phototropic stimulation

The role of myrosinase (beta-thioglucoside glucohydrolase, EC 3.2.3.1) in the phototropic response in radish hypocotyls was investigated. Unilateral illumination with blue light abruptly up-regulated the activity of myrosinase, which releases bioactive 4-methylthio-3-butenyl isothiocyanate (MTBI) from inactive 4-methylthio-3-butenyl glucosinolate (MTBG), in the illuminated halves of radish hypocotyls 10 min after onset of phototropic stimulation, peaking after 30 min and decreasing thereafter. The myrosinase activity in the shaded halves also increased, but was significantly lower than that in the illuminated halves. Furthermore, whether blue light illumination induces myrosinase gene expression was studied. Northern blotting analysis indicated that myrosinase mRNA levels were increased markedly in unilaterally illuminated hypocotyls, reaching maximum signal intensity within 10 min after onset of blue illumination, declining nearly to the control level thereafter. These results suggested that phototropic stimulation promotes myrosinase gene expression and myrosinase activity in the illuminated side, resulting in the conversion of inactive MTBG to active MTBI and simultaneously producing more active raphanusanins, causing a phototropic response.

Identification and characterization of two new members of the GRAS gene family in rice responsive to N-acetylchitooligosaccharide elicitor

We identified two new members of the GRAS gene family from rice, CIGR1 and CIGR2, which are rapidly induced upon N-acetylchitooligosaccharide elicitor perception. The predicated proteins encoded by CIGR1 and CIGR2 possess significant sequence similarity with previously identified members of the GRAS family, such as Arabidopsis SCARECROW, GAI, RGA, tomato Lateral suppressor, and rice SLR1, all of which have VHIID regions, likely to play a role in cellular signaling. Fusions of CIGR1 and CIGR2 with Green Fluorescent Protein were detected exclusively in the nuclei of onion epidermal cells. The expression of CIGR1 and CIGR2 was dependent on the structure of N-acetylchitooligosaccharides, which parallels the structural specificity for chitin binding to the plasma membrane-localized chitin-binding protein, and independent of de novo protein synthesis. Co-cultivation of rice cells with rice blast fungus strongly induced the expression of CIGR1 and CIGR2, whereas inoculation of suspension cells with phytopathogenic bacteria did not. We hypothesize that CIGR1 and CIGR2 act as transcriptional regulators in the early events of the elicitor-induced defense response in rice.

Cloning and characterization of a jasmonic acid-responsive gene encoding 12-oxophytodienoic acid reductase in suspension-cultured rice cells

In suspension-cultured rice ( Oryza sativaL.) cells, jasmonic acid (JA) functions as a signal transducer in elicitor N-acetylchitoheptaose-induced phytoalexin production. Differential screening of a cDNA library constructed using poly(A)(+) RNA from suspension-cultured rice cells treated with JA (10(-4) M) for 2 h yielded a cDNA for a gene that responded to exogenous JA by an increase in mRNA level. Nucleotide sequence analysis indicated that the cDNA encodes an homologue of the yeast Old Yellow Enzyme. The deduced amino acid sequence was very similar to the sequences of 12-oxophytodienoic acid reductases (OPR) 1 and 2 from Arabidopsis thaliana(AtOPR1 and AtOPR2) and OPR1 from tomato ( Lycopersicon esculentum) (LeOPR1). The cDNA-encoded protein purified from recombinant Escherichia coli cells as a hexahistidine-tagged fusion protein exhibited OPR activity similar to that of AtOPR1, AtOPR2, and LeOPR1, which catalyze reduction of (-)- cis-12-oxophytodienoic acid (OPDA) preferentially over (+)- cis-OPDA, a natural precursor of JA. Thus the rice enzyme was termed OsOPR1. The physiological roles of OsOPR1 are discussed. This is the first report of the cloning of an OPR gene from a monocot plant.

EL5, a rice N-acetylchitooligosaccharide elicitor-responsive RING-H2 finger protein, is a ubiquitin ligase which functions in vitro in co-operation with an elicitor-responsive ubiquitin-conjugating enzyme, OsUBC5b

EL5, a rice gene responsive to N-acetylchitooligosaccharide elicitor, encodes a RING-H2 finger protein with structural features common to the plant-specific ATL family. We show that the fusion protein of EL5 with maltose binding protein (MBP) was polyubiquitinated by incubation with ubiquitin, ubiquitin-activating enzyme (E1), and the Ubc4/5 subfamily of the ubiquitin-conjugating enzyme (E2). EL5 possesses the activity to catalyse the transfer of ubiquitin to the MBP moiety, and the RING-H2 finger motif of EL5 is necessary for this activity. Thus, we concluded that EL5 represents a ubiquitin ligase (E3). We also show that two rice E2s (OsUBC5a, OsUBC5b) of the Ubc4/5 subfamily function as E2 which catalyses EL5-mediated ubiquitination, and OsUBC5b was induced by elicitor, as well as EL5. These results strongly suggest that EL5 and OsUBC5b have roles in plant defense response through the turnover of protein(s) via the ubiquitin/proteasome system.

Cloning and characterization of cDNAs for the jasmonic acid-responsive Genes RRJ1 and RRJ2 in suspension-cultured rice cells

Two cDNA clones for jasmonic acid (JA)-responsive genes, RRJ1 and RRJ2, were isolated by differential screening from suspension-cultured rice cells treated with JA for 2 h. The putative RRJ1 protein is completely identical to that of a putative rice cystathionine gamma-lyase, while the putative RRJ2 protein is highly similar in sequence to a rice pyruvate decarboxylase, PDC1.

Synthesis of plaunotol derivatives and their antibacterial activities against Helicobacter pylori

Plaunotol, a known antiulcer drug, has antibacterial activities against Helicobacter pylori. Plaunotol thiourea derivatives 2--4 and diol derivatives 6--10 were designed in search for a compound with high antibacterial activities. Thiourea derivatives 2--4 were synthesized regioselectively using our effective synthetic route for plaunotol (1), and diol derivatives 6--10 were also synthesized. Their antibacterial activities against H. pylori are described and we found that the most potent antibacterial agent was C1-thiourea derivative 2c.

Isolation and analysis of expression mechanisms of a rice gene, EL5, which shows structural similarity to ATL family from Arabidopsis, in response to N-acetylchitooligosaccharide elicitor

Two rice cDNAs, EL5 and RRF1, were isolated and characterized. EL5 was responsive to N-acetylchitooligosaccharide, a biotic elicitor active in suspension-cultured rice cells. The structural specificity of the elicitor required for the expression of EL5 was consistent with other defense reactions observed in the experimental system, indicating that the elicitor signal to EL5 is transmitted through a single class of receptor-mediated recognition events. However, the intracellular signaling pathway to EL5 was distinct from those to other elicitor-responsive genes. Sequence analysis and alignment showed that a genomic sequence stored in rice genome databases in addition to EL5 and RRF1 belongs to the ATL family of RING-H2 finger motif proteins first isolated from Arabidopsis.

Oral beta-stimulants can inhibit passive cutaneous anaphylaxis in rats through an indirect inhibitory mechanism: possible involvement of afferent and efferent nervous system via gastric beta2-adrenoceptor stimulation

OBJECTIVE AND DESIGN

We previously demonstrated that oral l-ephedrine exerts an extremely rapid (within 20 s) inhibition of 48-h passive cutaneous anaphylaxis reaction (PCA) in rats by a possibly unidentified mode of action. In the present experiments, we elucidated the mechanism of the PCA inhibition by l-ephedrine using adrenoceptor agonists and antagonists.

MATERIALS

Rat antiserum was prepared with dinitrophenylated Ascaris suum extract + Bordetella pertussis.

TREATMENT

Passively skin-sensitised Wistar rats were mainly used. l-Ephedrine, and adrenoceptor agonists and antagonists were orally administered immediately before PCA provocation. Catecholamine depleting (6-hydroxydopamine, 6-OHDA), amine depleting (reserpine) or ganglion blocking (hexamethonium) agent was intraperitoneally or intravenously administered before the provocation.

METHODS

The effects of the drugs on PCA were assessed by inhibition of the dye leakage.

RESULTS

beta-(propranolol) and beta2-(butoxamine) blocking agents reduced the inhibition of PCA by l-ephedrine, while the inhibition was not altered by either an a-blocking agent (phentolamine) or a beta1-(atenolol) selective antagonist. On the other hand, beta-(isoproterenol) and beta2-selective (salbutamol) agonists showed extremely rapid inhibition of PCA. However, the beta-selective agonist (dobutamine) had no effect on the reaction. The pretreatment with hexamethonium, reserpine or 6-OH-DA substantially attenuated the inhibitory effect of l-ephedrine on PCA.

CONCLUSIONS

The results strongly suggest that beta2-adrenoceptors locate in the stomach and that their receptor excitement finally may lead to the inhibition of PCA via the stimulation of the central and peripheral nervous systems.

Immediate inhibition by oral l-ephedrine of passive cutaneous anaphylaxis of rats: indirect inhibition of anaphylactic chemical mediator release from the mast cell

OBJECTIVE AND DESIGN

We previously reported that oral l-ephedrine showed extraordinarily rapid inhibition of 48-h passive cutaneous anaphylaxis (PCA) in rats. In the present study, in vivo and in vitro experiments were performed to elucidate a possible mechanism for the inhibition.

MATERIALS

Rat antiserum was prepared with dinitrophenylated Ascaris suum extract + Bordetella pertussis.

TREATMENT

Wistar rats were passively skin-sensitised, actively sensitised or non-sensitised. l-Ephedrine immediately before provocations was orally or intravenously administered in in vivo experiments. In in vitro experiments, the drug was added at various time and concentrations before the challenge.

METHODS

The intensity of PCA was assessed by dye leakage method. Histamine and serotonin released in vitro or retained in the skin in vivo by anaphylaxis were assayed fluorometrically.

RESULTS

Oral l-ephedrine rapidly inhibited the PCA by inhibiting the release of histamine and serotonin from the reaction site, whereas anaphylactic histamine and serotonin releases from skin fragments were not affected by the drug. Furthermore, the orally administered drug influenced neither the histamine- nor serotonin-induced cutaneous vascular permeability.

CONCLUSIONS

These results were strongly indicative that the prompt suppression of the PCA by oral l-ephedrine was not exerted following the drug was absorbed from the gastrointestinal tract. Thus, the result may be from an indirect inhibition of chemical mediator release, possibly through an unidentified stimulation of the nervous system, but not from the inhibition of chemical mediator release by the direct interaction of drug to mast cells and not from the decreased vascular permeability.

Effect of shitei-to, a traditional Chinese medicine formulation, on pentylenetetrazol-induced kindling in mice

This study measured the effects of Shitei-To (STT), a traditional Chinese Medicine, which is a mixture of extracts from three medicinal herbs, Shitei (SI, Kaki Calyx; calyx of Diospyros kaki L. f.), Shokyo (SK, Zingiberis Rhizoma; rhizome of Zingiber officinale Roscoe) and Choji (CJ, Caryophylli flos; flowerbud of Syzygium aromaticum [L.] Merrill et. Perry), has long been used for the treatment of hiccups in Japan and China, against fully pentylenetetrazol-kindled seizures and on the development of pentylenetetrazol kindling in mice. Repeated administration of STT (3.0 g/kg p.o.) mildly retards the development of pentylenetetrazol-induced kindling in mice. STT also decreased the number of tonic-clonic convulsions resulting from progression kindling. On the other hand, STT had no effect on convulsions in fully pentylenetetrazol-kindled mice. These findings suggest that STT protects against the development of convulsions, and that STT may have therapeutic effects in the prevention of secondarily generalized seizures.

Stereochemistry of cis- and trans-hinokiresinol and their estrogen-like activity

Naturally occurring phenylpropanoids, hinokiresinol (trans-hinokiresinol) and nyasol (cis-hinokiresinol) were found to possess appreciable estrogen receptor binding activity. Strong differences in activity were observed between the geometrical isomers and enantiomers. Among these, (3S)-cis-hinokiresinol displayed the highest activity, one order of magnitude greater than the activity of genistein. Furthermore, cis- and trans-hinokiresinol stimulated the proliferation of estrogen-dependent T47D breast cancer cells, and their stimulatory effects were blocked by an estrogen antagonist, indicating that the compounds are estrogen agonists. In addition, the absolute configuration of C-3 in (+)-cis-hinokiresinol has been assigned as S by comparison with the circular dichroism spectra of the hydrogenated products prepared from cis and trans ((3S)-trans-hinokiresinol: previously assigned) isomers. These results incidentally provide us with an unambiguous answer to contradictory reports regarding the assignment of the full stereochemisry of cis- and trans-hinokiresinol that have existed in the literature for more than two decades.

The effects of habitat fragmentation on persistence of source-sink metapopulations in systems with predators and prey or apparent competitors

We consider systems with one predator and one prey, or a common predator and two prey species (apparent competitors) in source and sink habitats. In both models, the predator species is vulnerable to extinction, if productivity in the source is insufficient to rescue demographically deficient sink populations. Conversely, in the model with two prey species, if the source is too rich, one of the prey species may be driven extinct by apparent competition, since the predator can maintain a large population because of the alternative prey. Increasing the rate of predator movement from the source population has opposite effects on prey and predator persistence. High emigration rate exposes the predator population to danger of extinction, reducing the number of individuals that breed and produce offspring in the source habitat. This may promote coexistence of prey by relaxing predation pressure and apparent competition between the two prey species. The number of sinks and spatial arrangement of patches, or connectivity between patches, also influence persistence of the species. More sinks favor the prey and fewer sinks are advantageous to the predator. A linear pattern with the source at one end is profitable for the predator, and a centrifugal pattern in which the source is surrounded by sinks is advantageous to the prey. When the dispersal rate is low, effects of the spatial structure may exceed those of the number of sinks. In brief, productivity in patches and patterns of connectivity between patches differentially influence persistence of populations in different trophic levels.

Efficacy of shitei-to, a traditional Chinese medicine formulation, against convulsions in mice

The anticonvulsant effects of Shitei-To and its components on maximal electroshock seizures and chemical convulsions were examined. Shitei-To significantly prolonged the latency to bicuculline (2.0 mg/kg, s.c.)-induced clonic convulsions. Repeated treatment with Shitei-To also significantly prolonged the latency to strychnine (1.5 mg/kg, i.p.)- and pentylenetetrazol (90 mg/kg, i.p.)-induced clonic convulsions. On the other hand, Shitei-To had no effect on maximal electroshock seizures. Of the components of Shitei-To, Shitei had almost the same effect as Shitei-To against the clonic convulsions induced by the three chemical agents tested. These findings suggest that Shitei-To has anticonvulsant effects.

A highly stereoselective synthesis of plaunotol and its thiourea derivatives as potent antibacterial agents against Helicobacter pylori

Practical and highly stereoselective synthesis of diterpene alcohol, plaunotol (1) and its thiourea derivatives 2a, 3a and 4a, via Z-selective Wittig reaction between alpha-acetal ketone 5 and phosphonium salt 6 and their antibacterial activity against Helicobacter pylori are described.

Regulation of the chitinase gene expression in suspension-cultured rice cells by N-acetylchitooligosaccharides: differences in the signal transduction pathways leading to the activation of elicitor-responsive genes

Expression patterns of chitinase transcripts induced by N-acetylchitooligosaccharide elicitor were analyzed by northern blot hybridization in order to reveal a signal transduction pathway leading to the activation of class I chitinase genes (Cht-1 and Cht-3), which may play an important role in producing N-acetylchitooligosaccharide elicitor. The transcription level of both genes was enhanced in response to N-acetylchitooligosaccharides larger than pentaose at subnanomolar concentrations. These structure and dose dependencies were consistent not only with those for a 75 kDa high-affinity binding protein for N-acetylchitooligosaccharide elicitor in the plasma membrane, but also with other series of cellular responses including phytoalexin production and the expression of elicitor-responsive genes (EL2, EL3). Therefore, the elicitor signal to evoke these cellular responses including the activation of the chitinase genes could be common and transmitted into cells through the 75 kDa protein. However, the signal transduction pathway for the activation of the chitinase gene appeared to diverge from those for the other elicitor-responsive genes shortly after the signal perception. It was shown that the induction of chitinase expression by N-acetylchitooligosaccharide would require protein phosphorylation, but not de novo protein synthesis. The oxidative burst was demonstrated not to be necessary for transcriptional induction of the all four elicitor-responsive genes (Cht, PAL, EL2, EL3) by N-acetylchitooligosaccharide.

[Anatomical study of the levator labii superioris muscle]

The authors describe the anatomical characteristics of the levator labii superioris muscle by dissection in cadavers.

PURPOSE

We describe the characteristics of these muscle, the details and relations, hopefully contributing to the study of muscle of the face.

METHODS

Twenty faces of cadavers were dissected. The following features were studied: origin, insertion, length, width, thickness, relations, innervation and blood supply.

RESULTS

In all cases the muscle originated from the inferior orbital margin. Two insertions were observed: via lateral fibers, superficial to the orbicularis oris muscle and via deep fibers than form part of the raphe at the corner of the mouth (70%); via superficial fibers to the orbicularis oris muscle (30%). The average of the length was 24.66 mm and the average of the thickness was 3.57mm. The width at its insertion was 11.2mm, and at the origin was 15.96mm. The levator labii superioris muscle was found to be anterior to the levator anguli oris; it was posterior to the distal portion of the zygomaticus minor (90%) and posterior to the mid portion of the zygomaticus minor (10%). The innervation was from the inferior branch of the zygomatic nerve (facial nerve) and from the infraorbital nerve (trigeminal nerve). The inferior portion of the muscle is supplied by branches of the angular artery and the superior part from branches of the infraorbital artery.

Isolation, cDNA cloning, biological properties, and carbohydrate binding specificity of sieboldin-b, a type II ribosome-inactivating protein from the bark of Japanese elderberry (Sambucus sieboldiana)

A type II ribosome-inactivating protein (RIP) was isolated from the bark tissue of Japanese elderberry (Sambucus sieboldiana) and named sieboldin-b. Sieboldin-b is a heterodimeric protein consisting of 27- and 33-kDa subunits and showed strong ribosome-inactivating activity in vitro but did not show in vivo toxicity. The amino acid sequence of sieboldin-b deduced from the structure of the cDNA showed that both subunits of sieboldin-b are encoded on a single precursor polypeptide. Sieboldin-b has a structure homologous with the Neu5Ac(alpha 2-6)Gal/GalNAc-specific bark lectin from S. sieboldiana (SSA) and also typical type II RIPs such as ricin and abrin. Detailed analyses of carbohydrate binding properties of sieboldin-b revealed that sieboldin-b binds to Gal/GalNAc, similar to ricin/abrin, in spite of its highly homologous structure with SSA. The biological properties of these toxins/lectins are compared, and the possible explanation for such diversity is discussed.

Role of the sympathetic nervous system in the nocturnal fall in blood pressure

To evaluate mechanisms responsible for differences between patients showing a nocturnal fall in blood pressure ("dippers") and those showing no such fall in blood pressure ("nondippers"), we performed 24-hour (h) ambulatory blood pressure monitoring in 25 patients with untreated essential hypertension who were 37-49 years of age (16 men and 9 women). The diagnosis of essential hypertension was based on the patients' history, physical examination, routine laboratory tests, and intravenous pyelography. Blood pressure was measured by sphygmomanometer and by noninvasive ambulatory monitoring for 24 h. Exercise was performed on a supine bicycle ergometer. The initial workload was 50 W and was increased progressively by 25 W at 3-min intervals. Plasma and urinary norepinephrine levels were measured by high-performance liquid chromatography. Dippers were defined as patients with a difference of > 10 mmHg in the systolic BP or > 5 mmHg in the diastolic BP between daytime and nighttime. Eleven patients were dippers and 14 patients were nondippers. There was a positive correlation between the nocturnal fall in blood pressure and the rise in blood pressure during exercise (r = 0.54, p < 0.01), and the increase during exercise was greater in dippers than in nondippers. There was also a significant positive correlation between the urinary norepinephrine level and the fall in blood pressure at night (r = 0.75, p < 0.01). A significant increase in plasma norepinephrine during exercise was found in dippers, as compared with nondippers. These results suggest that in patients with hypertension a nocturnal fall in blood pressure is closely related to the blood-pressure response to exercise, and that the attenuation of sympathetic nervous activity might play an important role in the nocturnal decrease in blood pressure.

Cooperative action of lipo-chitin nodulation signals on the induction of the early nodulin, ENOD2, in soybean roots

Various lipo-chitin molecules were tested for their ability to induce the expression of the early nodulin, ENOD2, in Glycine soja roots. When inoculated separately onto G. soja roots, LCO-V (C18:1 delta 11,Mefuc), LCO-V (C18:1 delta 9,Mefuc), LCO-V (C16:0,Mefuc), and LCO-IV (C16:0) were unable to induce ENOD2 expression, even though these compounds had previously been shown to induce root hair curling, the formation of nodule-like primordia, and induction of the early nodulin, ENOD40. ENOD2 expression, however, was induced when any two of these molecules were inoculated in combination. Thus, the lipo-chitin nodulation signals appear to act cooperatively to induce ENOD2 expression. B. japonicum strains USDA110 and USDA135 and B. elkanii strain USDA61, all symbionts of soybean, were found to produce at least two distinct nod signals ([i.e., NodBj-V[C18:1,Mefuc] and NodBj-V[C16:0,Mefuc]). These two compounds were mixed in various ratios and tested for their ability to induce ENOD2 expression. The results indicate that the former compound must be present in equivalent or excess amount in order to obtain maximum ENOD2 expression. Additional nonspecific LCOs (e.g., LCO-IV[C16:2 delta 2,9; SO3]), incapable of inducing root hair curling or cortical cell division, were tested in combination with the four active LCOs listed above. It was found that any combination of one active LCO with a nonspecific LCO was sufficient to induce ENOD2 mRNA expression. The ENOD2 mRNA expression pattern detected by in situ hybridization closely resembled that found in bacterial-induced nodules with expression detected in cortical cells between primary and secondary meristems and around the vascular strands. These data demonstrate that the cooperative action of at least two LCO nodulation signals leads to a greater progression of nodule ontogeny as demonstrated by the expression of ENOD2, a marker gene for the differentiation of nodule parenchyma.

Nodule development induced by mutants of Bradyrhizobium japonicum defective in cyclic B-glucan synthesis

The soybean response to inoculation with B. japonicum mutants defective in cyclic beta-(1-->3), beta-(1-->6) glucan synthesis was examined by electron microscopy and by monitoring the expression of early and late nodulin genes. Two mutants were examined. Strain AB-14 is an ndvB mutant and is unable to synthesize beta-glucans. Strain AB-1 is an ndvC mutant and produces cyclic glucans containing 95 to 100% beta-(1-->3) glycosidic linkages. Nodules formed by either mutant were defective in nitrogen fixation activity. Soybean plants inoculated with strain AB-14 formed nodules roughly at the same rate as the wild-type strain USDA110, but nodulation by strain AB-1 was significantly delayed. Microscopy of nodules formed by strain AB-14 showed an overall ultrastructure similar to nodules formed by the wild type. However, in some nodules bacteroids were limited to only one part of the infected cells and in others the few bacteroids present showed signs of degradation. Nodulelike structures were formed by strain AB-1 that showed some signs of cellular differentiation. For example, clear parenchyma and sclerenchyma tissue could be seen. However, no infection threads or bacteria were evident in these structures. The expression of early (e.g., ENOD2 and ENOD55) and late (e.g., NOD26 and leghemoglobin) nodulins was examined. Nodules formed by strain AB-14 expressed all of the nodulins tested but at a reduced level. Expression of late nodulins was delayed in strain AB-14-induced nodules. Nodules formed by strain AB-1 were more strongly affected in nodulin expression. Although leghemoglobin synthesis was not detected, infection-specific nodulin transcripts of GmN93 and ENOD55 were detected. However, expression of the early nodulins ENOD2 and ENOD55 was considerably delayed and only apparent when assayed 21 days postinoculation. A low level of expression of intermediate nodulin GmN70 and late nodulin NOD26 could also be detected by 21 days postinoculation. The microscopy data show that tissue differentiation occurs in these nodules even in the absence of active bacterial invasion. These results demonstrate the importance of cyclic beta-(1-->3), beta-(1-->6) glucan synthesis to symbiotic development in soybean.

Expression of the early nodulin, ENOD40, in soybean roots in response to various lipo-chitin signal molecules

The lipo-chitin (LCO) nodulation signal (nod signal) purified from Bradyrhizobium japonicum induced nodule primordia on soybean (i.e. Glycine soja) roots. These primordia were characterized by a bifurcated vascular connection, cortical cell division, and the accumulation of mRNA of the early nodulin gene, ENOD40. A chemically synthesized LCO identical in structure to the Nod signal purified from B. japonicum cultures showed the same activity when inoculated on to soybean roots. Surprisingly, synthetic LCO or chitin pentamer, inactive in inducing root hair curling (HAD) or cortical cell division (NOI) in G. soja, induced the transient accumulation of ENOD40 mRNA. In roots inoculated with such LCO, ENOD40 mRNA was abundant at 40 h after inoculation but decreased to the background levels 6 days after inoculation. In contrast, nod signals active in inducing HAD and NOI induced high levels of ENOD40 accumulation at 40 h and 6 days after inoculation. In situ hybridization analysis showed that ENOD40 mRNA accumulated in the pericycle of the vascular bundle at 24 h after root inoculation with nod signal. At 6 days post-inoculation with nod signal, ENOD40 expression was seen in dividing subepidermal cortical cells. These results provide morphological and molecular evidence that nodule induction in soybean in response to purified or synthetic nod signal is similar, if not identical, to nodule formation induced by bacterial inoculation. Surprisingly, ENOD40 mRNA accumulation occurs in response to non-specific chitin signals. This suggests that, in the case of ENOD40, nodulation specificity is not determined at the level of initial gene expression.

Two novel genes rapidly and transiently activated in suspension-cultured rice cells by treatment with N-acetylchitoheptaose, a biotic elicitor for phytoalexin production

By using subtracted probes, two cDNA clones of rice, EL2 and EL3, were isolated as genes responsive within 6 min to N-acetylchitoheptaose, a potent biotic elicitor for phytoalexin biosynthesis. Analyses of the sequence of the cDNAs showed that both of EL2 and EL3 encoded basic proteins with no significant similarities to those of known genes.

Sialylated oligosaccharide-specific plant lectin from Japanese elderberry (Sambucus sieboldiana) bark tissue has a homologous structure to type II ribosome-inactivating proteins, ricin and abrin. cDNA cloning and molecular modeling study

Bark lectins from the elderberry species belonging to the genus Sambucus have a unique carbohydrate binding specificity for sialylated glycoconjugates containing NeuAc(alpha 2-6)Gal/GalNAc sequence. To elucidate the structure of the elderberry lectin, a cDNA library was constructed from the mRNA isolated from the bark tissue of Japanese elderberry (Sambucus sieboldiana) with lambda gt11 phage and screened with anti-S. sieboldiana agglutinin (SSA) antibody. The nucleotide sequence of a cDNA clone encoding full-length SSA (LecSSA1) showed the presence of an open reading frame with 1902 base pairs, which corresponded to 570 amino acid residues. This open reading frame encoded a signal peptide and a linker region (19 amino acid residues) between the two subunits of SSA, the hydrophobic (A-chain) and hydrophilic (B-chain) subunits. This indicates that SSA is synthesized as a preproprotein and post-translationally cleaved into two mature subunits. Homology searching as well as molecular modeling studies unexpectedly revealed that each subunit of SSA has a highly homologous structure to the galactose-specific lectin subunit and ribosome-inactivating subunit of plant toxic proteins such as ricin and abrin, indicating a close evolutionary relationship between these carbohydrate-binding proteins.

Physarum polycephalum haemagglutinins: effect of nutrition on synthesis, and their possible role in nature

The activity of haemagglutinins in plasmodia of Physarum polycephalum was measured under different culture conditions. The activity was markedly increased when the plasmodia were incubated in a non-nutrient salt medium. During starvation, significant amounts of haemagglutinins were found in the slime layer on the surface of the plasmodia. An increase in activity was not observed in the presence of actinomycin D or cycloheximide. Under starvation conditions, plasmodia are known to differentiate into either sclerotia (spherules) or fruiting bodies. Acceleration of haemagglutinin synthesis, however, was not always observed during spherulation and fruiting-body formation. Attempts to detect endogenous glycoconjugates that bind to the haemagglutinins were unsuccessful but we found that the haemagglutinins could bind to acidic polysaccharides produced by Escherichia coli K12. The bacterial glycoconjugates were purified and partially characterized. They contained N-acetylhexosamine residues which appeared to be important for binding with the haemagglutinins. It is possible that the haemagglutinins play a physiological role in the interaction with these organisms.

Alternative RNA products from a rice homeobox gene

Three cDNA clones were isolated from rice, OSH42, OSH44 and OSH45, which encode homeodomain sequences in the C-terminal region. The sequences of these cDNAs differ in the N- and C-termini, but they share an identical homeodomain and an acidic amino acid-rich region. The transcripts corresponding to these cDNAs are encoded by a single gene on rice chromosome 8. Differential transcription initiation results in a large transcript comprised of exons 1 and 3-7 and a smaller transcript comprised of exons 2-7. The larger transcript is constitutively expressed in all tissues tested, while the smaller transcript is expressed in leaves, stems and rachis but not in roots, flowers, or suspension callus cells. Alternative splicing also occurs at three different acceptor sites in intron 6 in all tissues tested. The GAL4 DNA-binding domain of yeast was used to study the function of various protein domains. The acidic amino acid-rich region activates the expression of a reporter gene controlled by the GAL4 target sequence, indicating that it functions as a transactivation domain. The larger transcript encodes a unique alanine and glycine-rich region on the N-terminal side of the acidic region, which is not encoded by the smaller transcript. This region completely suppresses the transactivation activity of the acidic region. This suggests that the product of the larger transcript fails to activate the expression of the target gene(s) while the product of the smaller transcript activates the expression of its target gene(s).

Freeman-Sheldon syndrome: surgical correction of microstomia

In this report, we describe a case of microstomia associated with club feet and ulnar deviation of the hands (Freeman-Sheldon syndrome) and the surgical technique for correction of the oral deformity.

Nucleotide sequence of the gene for phenylalanine ammonia-lyase of rice and its deduced amino acid sequence

The whole structure of the gene for phenylalanine ammonia-lyase of rice, designated as GP-28, was determined. The gene included one intron located between nucleotides 557 and 2048, corresponding to the second and third letters, respectively, of the arginine codon at position 136 which is conserved in the genes of other plant species. The open reading frame was capable of encoding a 716 amino acid sequence, which showed 73.3% similarity with that of parsley. In the carboxyl-terminal region, an arginine-rich sequence common to the rice enzyme was found, which showed low similarity with those of dicot plants.

Effect of subject's family name on visual event-related potential in schizophrenia

Visual event-related potentials (ERPs) were recorded from 15 schizophrenics and 15 age-matched and gender-matched controls, while they performed a modified version of the oddball paradigm. Each subject was required to detect target stimuli among a random sequence of stimuli under two conditions, name and color. In the name condition the stimulus sequence consisted of the subject's family name (deviant 18%), four other family names (standard 73%), and a city name (target 9%). In the color condition the respective stimuli were a pair of solid red circles, four white paired-arrows, and a pair of white plus and minus signs. ERPs elicited by stimuli contained triphasic potentials of P2, N2, and P3. In controls these waves were selectively enhanced for the subject's family name as compared with standards, whereas in schizophrenics no significant difference between the subject's family name and other names was observed. In contrast, selective enhancement for color deviants was observed in both subject groups. These results suggest that impairment of involuntary attention, especially for familiar and significant stimuli such as names in daily life, may underlie disturbances of attentionally controlled central processing in schizophrenia.

Identification of carrot cDNA clones encoding a second putative proliferating cell-nuclear antigen, DNA polymerase delta auxiliary protein

The proliferating cell-nuclear antigen (PCNA) plays a key role in the control of eukaryotic DNA replication. We have isolated two cross-hybridizing groups of cDNA encoding carrot homologs of PCNA. Sequence analysis and Southern-blot experiments showed that the cDNA were derived from two distinct genes. One corresponded to the typical PCNA, which is known to be highly conserved in eukaryotes from yeast to man; its mRNA is 1.2 kb in size and the calculated molecular mass of the protein is 29 kDa. The other encoded a larger PCNA homolog which has not previously been reported; the mRNA is 1.5 kb in size, the N-terminal three quarters (calculated molecular mass, 29 kDa) of the protein product is 88% identical at the amino acid level to the typical PCNA, but the protein has an extra C-terminal domain of 11 kDa. Both PCNA homologs were apparently coexpressed concomitant with somatic embryogenesis. The mRNA level of the novel homolog is 10-20% that of the typical PCNA in the embryos. The presence of the second putative PCNA may provide new insight into studies on the mechanism of DNA replication in eukaryotes.

Structure and some characterization of the gene for phenylalanine ammonia-lyase from rice plants

A nearly full-length cDNA and a genomic clone were isolated that encoded the phenylalanine ammonia-lyase (PAL) of rice plants, and the complete nucleotide sequences were determined. The gene encodes a polypeptide of 701 amino acid residues. The deduced amino acid sequence is highly similar to that of PAL from Phaseolus vulgaris deduced from an incomplete cDNA fragment. The cloned gene spans 4412 bp and consists of two exons and one intron. The site of initiation of transcription was located -86 nucleotides (position 1) upstream from the translational initiation codon by the primer-extension method. Sequences analogous to TATA-box and GC-box were found in the 5'-upstream region from the transcriptional initiation site. Southern blot analysis showed that the PAL gene of rice plants exists as a small multi-gene family. Within this family, the genomic clone isolated in this study was shown to be responsive by light. This also indicated that this genomic sequence functions as a gene for phenylalanine ammonia-lyase in rice plants in vivo.

Complete structure of the gene for phosphoenolpyruvate carboxylase from maize

Phosphoenolpyruvate carboxylase is a key enzyme in photosynthesis in some plants that exploit the C4 photosynthetic pathway for the fixation of CO2. We cloned the gene for this enzyme from maize genomic libraries and analyzed its complete primary structure. The sequence of the cloned gene spans 6781 bp and consists of 10 exons and 9 introns. The site of initiation of transcription is located 84 nucleotides upstream from the first nucleotide of the initiation codon (position -84), as determined by the method of primer-extension analysis. The analysis suggests that there is another initiation site located at position -81. The 5'-flanking region of the gene lacks typical TATA and CCAAT elements in the anticipated regions, but there is a TATA-similar sequence (TATTT) around the -30 regions as well as sequence homologous to the Sp-1 protein-binding site (CCGCCC). Six long, direct repeated sequences and a light-responsive element are also present in the 5'-flanking region. The results of Southern blot analysis indicated that the phosphoenolpyruvate carboxylase gene exists as a small multi-gene family, but the enzyme that is expressed at high levels in green leaves and is involved in C4 photosynthesis is encoded by a single-copy gene in the maize genome.

Synthesis and assembly of H+-ATPase complex by isolated "rough" thylakoids

The synthesis and assembly of chloroplast H+-ATPase complex were studied by analyzing the incorporation of [35S]methionine into the constituent subunits with isolated intact chloroplasts and with thylakoid membranes that had been prepared from the chloroplasts so that they would retain ribosomes. The complex was isolated from thylakoids after labeling and identified by immunoprecipitation with an antiserum specific to CF1. The mechanism for the assembly of the complex was demonstrated to be active in the isolated chloroplasts by the following observations: the plastid genome-regulated subunits (alpha, beta, epsilon, I, and III) were labeled by in organello translation and recovered with the complex, and three other subunits (gamma, delta, and II) were labeled when intact chloroplasts were incubated with translation products from polyadenylated RNA. The two largest subunits, alpha and beta, were translated on thylakoid-bound ribosomes when the thylakoid membranes were incubated with soluble factors from Escherichia coli. They were recovered with the H+-ATPase complex, suggesting that they are translated on the bound ribosomes in the chloroplast, and that the isolated membranes retain the ability to assemble a complete complex. Provided that these observations are the result of de novo assembly of the complex, the imported and processed nuclear-coded subunits are presumed to be pooled not in stroma but on the membrane.