Pyriproxyfen influences growth as well as thyroid hormone-related and gh/igf-1 gene expression during the early life stage of zebrafish (Danio rerio)

Pyriproxyfen is an agricultural chemical pesticide that has been detected in the aquatic environment. This study aimed to clarify the effects of pyriproxyfen on the growth as well as thyroid hormone- and growth-related gene expression of zebrafish (Danio rerio) during its early life stage. Pyriproxyfen exhibited a lethal effect in a concentration-dependent manner: the lowest and no effect concentrations were 250.7 and 111.7 μg/L, respectively. These concentrations were considerably higher than the residual environmental concentrations, indicating the low risk of this pesticide when present at such concentrations. In the zebrafish group treated with 56.6 μg/L pyriproxyfen, thyroid hormone receptor β gene expression levels remained unchanged, whereas thyroid-stimulating hormone β subunit, iodtyronin deiodinase 2, and thyroid hormone receptor α gene expression levels significantly decreased compared with the control group expression levels. In zebrafish treated with 111.7 or 250.7 μg/L pyriproxyfen, iodtyronin deiodinase 1 gene expression levels significantly increased. These results indicate that pyriproxyfen disrupts thyroid hormone activity in zebrafish. Furthermore, pyriproxyfen exposure inhibited zebrafish growth; consequently, we examined the expression of growth hormone (gh) and insulin-like growth factor-I (igf-1), which are important for growth. Pyriproxyfen exposure suppressed gh expression; however, the igf-1 expression levels remained unchanged. Therefore, growth inhibition due to pyriproxyfen exposure was attributed to the suppression of gh expression.

Fargosides A-E, triterpenoid saponins from Holboellia fargesii

Five new triterpenoid saponins, fargosides A, B, C, D, and E, were isolated from the roots of Holboellia fargesii. The structures of fargosides A-E were elucidated on the basis of chemical and physicochemical evidence and found to be 3beta,20alpha-dihydroxy-29-norolean-12-en-28-oic acid 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (1), 3beta,20alpha,24-trihydroxy-29-norolean-12-en-28-oic acid 23-O-beta-D-fucopyranosyl-(1-->2)-[alpha-L-arabinopyranosyl-(1-->3)]-beta-D-glucopyranoside (2), 3beta,23-dihydroxy-30-norolean-2,20(29)-dien-28-oic acid 3-O-alpha-L-arabinopyranosyl-(1-->2)-[beta-D-glucopyranosyluronic acid-(1-->3)]-alpha-L-arabinopyranoside (3), 3beta,23-dihydroxy-30-norolean-12,20(29)-dien-28-oic acid 3-O-methyl beta-D-glucopyranosyluronate-(1-->3)-alpha-L-arabinopyranoside (4), and 3beta,23-dihydroxy-olean-12-en-28-oic acid 3-O-methyl beta-D-glucopyranosyluronate-(1-->3)-alpha-L-arabinopyranoside (5), respectively.

Comparative toxicokinetic study of rubber antioxidants, 2-mercaptobenzimidazole and 2-mercaptomethylbenzimidazole, by single oral administration in rats

Toxicokinetics of 2-mercaptobenzimidazole (MBI) and 2-mercaptomethylbenzimidazole (MMBI), rubber antioxidants with thioureylene structure, were compared after single oral administration in rats. Male Wistar rats received single oral administration of 2, 10, 50 and 250 mg/kg of MBI or MMBI. The serum and urine concentrations of MBI and MMBI were determined by HPLC. MBI and MMBI showed similar Cmax values, but the former disappeared slower in the serum than the latter and resulted in its larger AUC values. Analyses of MBI, MMBI and their desulfurated metabolites in urine suggested that these differences were due to their metabolic elimination rates. On the other hand, MBI and MMBI caused similar acute toxicities, such as loss of locomotive activity, ataxic gait, adoption of prone or side position and coma, being severer with higher serum concentrations at the moment. Similar acute toxicities between MBI and MMBI were explained by similar Cmax values at the same dose. It was suggested from these results that the slower disappearance and larger AUC values of MBI in the serum compared to MMBI might explain the strong thyroid toxicity which has been observed by repeated administration of MBI, but very weak thyroid toxicity by MMBI.

Genomic organization and expression analysis of the mouse qkI locus

qkI, encoding a KH domain-containing RNA binding protein, has been isolated as a candidate gene for the mouse neurological mutation quaking. Here, we describe detailed studies on its genomic structure and expression pattern. We isolated approximately 1 Mb of genomic region containing the quaking locus and determined its genomic organization. The qkI locus contains at least 9 exons spanning approximately 65 kb of DNA. It gives rise to six distinct transcripts encoding, theoretically, five different protein isoforms. Exons 1 through 4 are shared by all the transcripts, whereas coding exons and two distinct 3'-UTRs downstream to the exon 4 are differentially utilized. One isoform has a truncated KH domain and may act as an antagonist to the others. These findings and identification of a single transcription initiation site suggest that differential expression of each transcript is regulated by alternative splicing. Expression of each alternative transcript and protein product was also examined. Two types of transcripts, 5 kb-A and B, are most abundant in the brain of newborn mice and are gradually downregulated thereafter. In contrast, the other three messages, 6 kb, 7 kb-A and B, increase as myelination proceeds and peak at 2 weeks of age, corresponding to the most active stage of myelination. Although the qkI messages and their products are abundant in brain and heart, a lower level of expression was found in various other tissues tested. Alternative transcripts that share the same 3'-UTR showed very similar expression patterns, suggesting a regulatory role of the 3'-UTRs in qkI gene expression.

Upstream element of the sea urchin arylsulfatase gene serves as an insulator

Insulator DNAs functionally isolate neighboring genes by blocking interactions between distal cis-regulatory elements and promoters. Here we report that a DNA fragment located in the upstream region of sea urchin, H. pulcherrimus, arylsulfatase (HpArs) gene blocks the interaction of the Ars enhancer when positioned between the enhancer and the target promoter, in an orientation dependent manner. The Ars insulator works only 3' to 5' direction and has no significant stimulatory or inhibitory effects on its own promoter. In transgenic Drosophila, the Ars insulator blocks the interaction between even-skipped stripe enhancer and its target promoter. The insulation mechanism operates also unidirectionally in Drosophila. We also show that the efficiency of transformation of HeLa cells is enhanced when the integrated gene is flanked by the Ars insulator, suggesting the sea urchin insulator overcomes the position-dependent transgene expression in mammalian cells. These results demonstrate that the mechanism of action of the insulator has been conserved throughout evolution.

Two new triterpenoid saponins from Platycodon grandiflorum

Two new triterpenoid saponins, platycoside D [3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->6)-beta-D- glucopyranosyl-2 beta, 3 beta, 16 alpha, 23-tetrahydroxyolean-12-ene-28-oic acid 28-O-beta-D- apiofuranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnop yranosyl- (1-->2)-alpha-L-arabinopyranoside] and platycoside E [3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl- (1-->6)-beta-D-glucopyranosyl-2 beta,3 beta,16 alpha,23,24-pentahydroxyolean-12-ene-28-oic acid 28-O-beta-D-apiofuranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alp ha-L- rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside] were isolated from the roots of Platycodon grandiflorum. Structural determination is based on spectral and chemical evidence.

Tctex3, related to Drosophila polycomblike, is expressed in male germ cells and mapped to the mouse t-complex

Tctex3 showing restricted expression in male germ cells has been isolated during the process of chromosome walking in the mouse t-complex region. The total sequence of Tctex3 cDNA predicts a protein of 580 amino acids with two C4HC3 type PHD fingers. The region containing this conserved motif is shared among members of the Polycomblike proteins that include the mouse M96 and Drosophila Polycomblike. A partial cDNA for a human homolog of Tctex3, HUTEX3, has also been isolated. Mouse Tctex3 gene was mapped adjacent to Tsc2 gene on mouse Chromosome (Chr) 17, and HUTEX3 was located closely to HSET gene in the HLA class II region of chromosome 6.

Studies on the constituents of Ailanthus integrifolia

A new phenolic glycoside, 3,4,5-trimethoxyphenol-1-(6-xylopyranosyl)glucopyranoside, was isolated together with twenty known compounds identified as koaburaside, 3,4,5-trimethoxyphenol, 5,7-dihydroxychromone-7-neohesperidoside, naringin, neoeriocitrin, p-coumaric acid, vanillin, vanillic acid, coniferyl aldehyde, ferulic acid, trans-triacontyl-4-hydroxy-3-methoxycinnamate, p-methoxycinnamic acid, 2,6-dimethoxybenzoquinone, 2-(1-hydroxyethyl)naphtho[2,3-b]furan-4,9-dione, 2-acetylnaphtho[2,3-b]furan-4,9-dione, 2-(1-hydroxyethyl)-6-methoxynaphtho[2,3-b]furan-4,9-dione, 2-acetyl-6-methoxynaphtho[2,3-b]furan-4,9-dione, specioside, jioglutin C and rehmaglutin D from the bark of Ailanthus integrifolia Lamk (Simaroubaceae).

Isolation of cDNAs for LCE and HCE, two constituent proteases of the hatching enzyme of Oryzias latipes, and concurrent expression of their mRNAs during development

The hatching enzyme of medaka consists of two types of proteases (HCE, LCE). cDNA clones for LCE and HCE were isolated from a lambda gt11 cDNA library constructed with poly(A)+ RNA of Day 3 embryos. LCE cDNA is 936 bp long and contains an 813-bp open reading frame encoding a preproenzyme with a 20-amino-acid signal sequence, a 51-amino-acid propeptide, and a 200-amino-acid mature enzyme. For HCE, two distinct cDNAs (HCE21, HCE23) having nucleotide sequences with 92.8% similarity were obtained. These cDNAs contain open reading frames encoding preproenzymes of 279 and 270 amino acids, respectively. The mature enzyme forms of both consist of 200 amino acids, the similarity between them being 95.5%. On Northern blotting analysis, the transcripts of LCE and HCE genes were first detected coincidentally in Day 2 embryos shortly before the production of LCE and HCE, accumulated thereafter in parallel, and dramatically decreased after hatching. The amino acid sequence, the HExxH motif, which is known to constitute an active site in some Zn proteases, is also found in LCE and HCE. However, the sequence analyses strongly suggest that both the enzymes belong to the astacin (protease) family, being distinct from sea urchin hatching enzyme, which is reportedly similar to collagenase.

Optoelectronic associative memory using an advanced optical neurochip

A drastic improvement in the performance of the associative memory was achieved using an optical neurochip. The experimental recognition rate agreed well with computer simulation for the associative memory.

Optical flip-flop based on parallel-connected AlGaAs/GaAs pnpn structures

An optical flip-flop using parallel-connected pnpn (thyristor) structures is demonstrated for the first time to our knowledge. We utilize the differential optical switching technique for inverting the state of the flip-flop and the slow dissipation of carriers stored in the gate layers of pnpn structures for retaining the state. The flip-flop operation with 7.2 pJ of optical input energy was attained by using an AlGaAs/GaAs device. The expansibility to monolithic two-dimensional arrays, the high on-off contrast, and the high optical gain of the flip-flop are useful in the design and fabrication of optical parallel processing systems.

Studies on the constituents of Indonesian Picrasma javanica. III. Structures of new quassinoids, javanicins A, C and D

Three new quassinoids, javanicins A, C and D, were isolated from the bark of Picrasma javanica (Simaroubaceae). The structures were established on the basis of spectroscopic data and chemical evidence.

GaAs/AlGaAs optical synaptic interconnection device for neural networks

A GaAs/AlGaAs optical synaptic interconnection device for neural networks is reported for the first time to our knowledge. This device consists of a light-emitting-diode array, an interconnection matrix, and a photodiode array, which are integrated into a hybrid-layered structure on a GaAs substrate. The device structure and characteristics are reported in detail. The fabricated device can simulate a 32-neuron system. Experimental results of the Hopfield associative memory with three stored vectors are also described.

Distributions of H+,K+-ATPase and Cl-,HCO3(-)-ATPase in micromere-derived cells of sea urchin embryos

In cultured cells derived from isolated micromeres of sea urchin eggs, H+,K+-ATPase activity, which became detectable simultaneously with the initiation of spicule formation, was localized in the plasma membrane and the microsome fractions. Activities of marker enzymes for plasma membrane, 5'-nucleotidase, Na+,K+-ATPase, and adenylate cyclase, were found to be high in the plasma membrane fraction. Considerable activity of rotenone-insensitive NADPH-cytochrome c reductase, a marker enzyme for microsome, was detectable in the microsome fraction. These fractions exhibited barely any appreciable activity of markers for the other organellae. H+,K+-ATPase in plasma membrane probably mediates H+ release from the cells, in which H+ is produced in overall reaction to form CaCO3, the main component of spicules, from Ca2+, CO2 and H2O. Cl-,HCO3(-)-ATPase activity was also found in these two fractions before and after the initiation of spicule formation. After initiation, the skeletal vacuole fraction was obtained from subcellular structures containing spicules. Considerable activity of Cl-,HCO3(-)-ATPase was observed in this fraction, which exhibited a weak activity of UDP-galactose: N-acetylglucosamine galactosyltransferase, a marker enzyme for Golgi body. Cl-,HCO3(-)-ATPase in the skeletal vacuole membrane probably mediates HCO3- transport into the vacuoles to supply HCO3- for spicule formation.

Change in the activity of Cl-,HCO3(-)-ATPase in microsome fraction during early development of the sea urchin, Hemicentrotus pulcherrimus

In sea urchin embryos, primary mesenchyme cells, descendants from micromeres produced at the 16-cell stage, form spicules or CaCO3 deposits in their skeletal vacuoles, at the post-gastrula stage. Micromeres isolated at the 16-cell stage also differentiate into spicule-forming cells during their culture at the same time schedule as in the embryos. The present study was planned to observe change in the activity of Cl-,HCO3(-)-ATPase, which was expected to contribute to the carbonate supply for CaCO3 deposition, during development. ATP-hydrolysis in the microsome fraction, obtained from embryos of the sea urchin, Hemicentrotus pulcherrimus, and from micromere-derived cells in culture was stimulated by Cl- and HCO3- in the presence of ouabain and EGTA. The ATP-hydrolysis was inhibited by ethacrynic acid, an inhibitor of Cl-,HCO3(-)-ATPase. The activity of Cl-,HCO3(-)-ATPase in embryos and in micromere-derived cells increased during development, keeping pace with the rate of calcium deposition in spicules. Formation of calcified spicules in the cultured micromere-derived cells was inhibited by ethacrynic acid. These results indicate that Cl-,HCO3(-)-ATPase plays an important role in the mechanism of CaCO3 deposition in the primary mesenchyme cells.

Carbonic anhydrase activity in developing sea urchin embryos with special reference to calcification of spicules

Eggs and embryos of the sea urchins Anthocidaris crassispina and Hemicentrotus pulcherrimus did not exhibit significant changes in carbonic anhydrase activity during early development. Acetazolamide inhibited enzyme activity in homogenates of embryos and inhibited the formation of calcified spicules in a culture of micromeres at concentrations between 40 and 100 microM. Acetazolamide allowed intact embryos to develop to quasi-normal plutei but inhibited calcium deposition in the spicules. It is suggested that carbonic anhydrase contributes to CaCO3 deposition in the spicule.

Mechanism for electrosilent Ca2+ transport to cause calcification of spicules in sea urchin embryos

Embryos of the sea urchin, Hemicentrotus pulcherrimus, kept in sea water containing the calcium antagonists, diltiazem and verapamil, or an anion transport inhibitor, 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene (DIDS), during a developmental period between the mesenchyme blastula and the pluteus corresponding stage, became abnormal plutei with poorly developed arms and quite small spicules. Treatment with ethacrynic acid and furosemide, inhibitors of chloride transport, during the same period of development yielded quasi-normal plutei with poor spicules and somewhat developed arms. In late gastrulae, the inhibitory effects of these calcium antagonists and DIDS on the uptake of 45Ca2+ in whole embryos were as strong as those on 45Ca deposition in spicules, whereas the effects of chloride transport inhibitors on calcium deposition in the spicules were markedly stronger than on its uptake in whole embryos. Electrosilent uptake of Ca2+ seems to be established mainly by coupled influx of chloride in the cells which mediate spicule calcification, and by concomitant influx of anions in the other cells. In swimming blastulae, 45Ca2+ uptake was inhibited by calcium antagonists and DIDS, but not by chloride transport inhibitors. Ca2+ uptake probably becomes coupled with chloride influx only in embryos in which spicule calcification occurs.

Optical LiNbO(3) 3-branched waveguide and its application to a 4-port optical switch

An optical multimode 3-branched waveguide in Ti-diffused Z-cut LiNbO(3) is discussed experimentally and theoretically. The guided light was selectively fed into three branches with the extinction ratio of nearly 10 dB at an applied voltage of V(0) = +/-25 V. As an example of the applications, we propose a 4-port optical switch which consists of 3-branched waveguides and bent waveguides. The bent waveguide with a 0.5-mm radius of curvature was fabricated in Nb(2) O(5) /Ti:LiNbO(3).