A new synthesis ofβ-fluoroaspartic acid

Summary -Fluoroaspartic acid, a new amino acid, was synthesized by a diazotization of diaminosuccinic acid in liquid hydrogen fluoride.Synthesis of Amino Acids and Related Compounds, part 21.—Part 20: Y. Ozaki, S. Maeda, M. Miyoshi and K. Matsumoto, Synthesis, 216 (1979).We would like to acknowledge Dr I. Chibata for his encouragement in this work.     

A synthesis of α-brazan and the related quinone

Résumé On décrit une methode pour la synthèse des -brazan et -brazanquinone deKruber.     

Glucose-evoked recovery of hepatic thyroxine 5′-deiodinase independent of de novo protein synthesis in fasted rat

Summary The glucose-evoked recovery of Type I thyroxine 5-deiodinase activity in the hepatic microsomes of fasted rat was not inhibited by either cycloheximide, puromycin or actinomycin D during 3 h after glucose feeding; however, [³H]-leucine uptake by the liver or the hepatic microsomal fraction was significantly inhibited by cycloheximide and puromycin but not by actinomycin D. These results indicate that the glucose-evoked recovery of deiodinase activity may be independent of de novo protein synthesis.     

Inhibitory effect of β-ecdysone on protein synthesis by blowfly fat body in vitro

Summary Synthesis of blow fly calliphorin and other blood proteins by larval fat body in organ culture is inhibited by -ecdysone. The findings suggest a novel function for the hormone.     

One-step synthesis route of the aligned and non-aligned single crystalline α-Si_3N_4 nanowires

This paper reports the bulk synthesis route of the aligned and non-aligned high-qualityα-Si 3 N4 nanowires(NWs) which were grown directly from the Si substrate by vapor phase deposition at 1050℃.The as-grown products were characterized by employing XRD,SEM,HRTEM and photoluminescence.The microscopic results revealed that the products consist of single crystalline aligned and non-alignedα-Si 3 N4 NWs having a same diameter range of 30-100 nm and different lengths of about hundreds of microns.The XRD observation revealed that the products consist ofα-phase Si 3 N4 NWs.The room temperature PL spectra indicated that the NWs have good emission property.The non-aligned NWs were formed at lower temperature as compared with aligned NWs.Our method is a simple and one-step procedure to synthesize the bulk-quantity and high-purity aligned and non-alignedα-Si 3 N4 NWs at a relatively low temperature.The possible growth mechanism was also briefly discussed.     

Pineal ‘synaptic’ ribbon numbers and melatonin synthesis of rat are resistant to guanethidine sympathectomy

Chemical sympathectomy is widely used to study the impact of the noradrenergic system on neuronal and neuroendocrine circuits. We tested the effects of intraperitoneal injections of guanethidine, an adrenergic neuron blocking agent, on selected functional parameters of the rat pineal gland which are known to be under sympathetic influence. The reliability of the method was demonstrated by the clear enophthalmus developed by experimental animals. However, neither the numbers of synaptic ribbons nor melatonin synthesis differed between treated and control rats, both parameters exhibiting the nocturnal increase seen in intact animals. These results are in striking contrast to those obtained upon chemical sympathectomy with 6-hydroxydopamine or surgical superior cervical ganglionectomy. We conclude that guanethidine is not capable of sufficiently removing noradrenergic influence from the rat pineal gland, and that this substance is thus inferior to other experimental methods of sympathectomy.     

Paradoxical effect of 1-β-D-arabinofuranosyl cytosine triphosphate on bleomycin-induced unscheduled DNA synthesis in permeable sarcoma cells

Summary 1--D-Arabinofuranosyl cytosine-5-triphosphate (araCTP), an inhibitor of DNA synthesis, paradoxically enhanced unscheduled DNA synthesis (USD) induced by bleomycin in permeable mouse sarcoma cells. A greater enhancing effect of araCTP on bleomycin-induced USD was observed with lower concentrations of dCTP in the assay mixture. USD measured without bleomycin in nuclei isolated from mouse sarcoma cells was not enhanced, but inhibited by araCTP.Acknowledgments. The authors wish to thank Nippon Kayaku Co. (Tokyo, Japan) for providing copper-free bleomycin A₂. This research was supported in part by a grant from the Japan Ministry of Education, Science and Culture.     

Is there any quantitative relationship between the synthesis and the breakdown of nucleic acids in living cells?

Zusammenfassung Es wurde untersucht, ob die Biosynthese der Nukleinsäuren in wachsenden Systemen mit dem Abbau von ursprünglich vorhandenen Nukleinsäuren derselben Art gekoppelt ist. Die Versuche wurden mit Bakterien (E. coli) und mit Rattenleber gemacht. Die in der Zelle vorhandenen Nukleinsäuren waren mit P³² markiert, und es wurde der Verlust an Radioaktivität in jeder der beiden Nukleinsäuretypen im Laufe des Wachstums gemessen. Die Resultate wiesen darauf hin, dass das Auftreten von neuen Nukleinsäuremolekeln in der lebenden Zelle ohne den begleitenden Abbau der alten Molekeln stattfinden kann.

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Supported in part by the Scientific Research Fund of the Ministry of Education given to the Synthetic Research Group on Nucleic Acids. The warm encouragement given to this work by Prof.J. Kamahora of this Institute is heartily acknowledged. We are further indebted to Dr.T. Miura, Department of Radiology, University of Osaka Medical School, for his help in this work.     

Effect of α- and β-ecdysone on DNA synthesis inAeshna cyanea (Insecta,Odonata) midgut

Summary InAeshna cyanea larvae, - and -ecdysone stimulate DNA synthesis in the midgut regenerative cells. In last larval instar, the number of cells obtained after the imaginal epithelium genesis is greater after - than after -ecdysone supply. Such a result should be compared with the imaginal epithelium differentiation which occurs earlier after -ecdysone injection.     

Prothoracic gland synthesis of 3-dehydroecdysone and its hemolymph 3β-reductase mediated conversion to ecdysone in representative insects

Summary The prothoracic glands of a variety of insects were tested for their ability to synthesize ecdysteroids in vitro. More specifically, they were evaluated for their ability to produce 3-dehydroecdysone and ecdysone using both radioimmunoassay and reverse phase high performance liquid chromatography. Three categories of insect prothoracic glands were noted: a) those producing much more 3-dehydroecdysone than ecdysone; b) glands synthesizing almost equivalent amounts of each of these two ecdysteroids; c) prothoracic glands that yielded more ecdysone than 3-dehydroecdysone. In addition, the 3-oxoecdysteroid 3-reductase activity of the hemolymph of these insects was evaluated for its ability to convert 3-dehydroecdysone to ecdysone. The lepidopteran species tested yielded the most potent enzyme activity, although activity was demonstrated in members of other orders. These data indicate that the dehydroecdysone-ecdysone axis is not restricted to moths and butterflies.     

Sporulation and δ-endotoxin synthesis by Bacillus thuringiensis

Bacillus thuringiensis is distinguished from the very closely related Bacillus cereus and Bacillus anthracis by the presence of several plasmid-encoded δ-endotoxin genes. These δ-endotoxins, synthesized as protoxins, are produced in large quantities during sporulation and are packaged into intracellular inclusions. Ingestion of the inclusions by insect larvae leads to protoxin solubilization and conversion to toxins each specific for one of several orders of insects. The toxins form cation-selective channels in the membrane of cells lining the larval midgut with subsequent lethality. In most cases, δ-endotoxin synthesis and sporulation are closely coupled. The latter process in B. thuringiensis is probably virtually identical to that in Bacillus subtilis with the additional use of mother cell sporulation forms of RNA polymerase for the synthesis of the δ-endotoxins. There are other more subtle plasmid-encoded functions or plasmid interactions related to regulating protoxin synthesis. Consideration of both plasmid and chromosomal genes is thus critical for defining this organism.     

A simple synthesis of (E)-3-formylbut-2-enenitrile,and its use as a precursor of isotope-labelled zeatin and (±) dihydrozeatin

Summary (E)-3-Formylbut-2-enenitrile (4) is synthesized in 2 steps by reacting pyruvaldehyde dimethylacetal and acetonitrile in the presence of sodium methoxide, followed by acid hydrolysis to give 58% overall yield on distillation. The aldehyde4 can be stepwise and selectively reduced to (E)-3-hydroxymethylbut-2-enylamine (7a) in 37% total yield or exhaustivelyb reduced in 1 step to (±)-4-hydroxy-3-methylbutylamine (6) in 46% total yield. Compound7a and6 can be condensed with 6-chloropurine to give zeatin and (±)dihydrozeatin respectively. This provides a readily accessible method for isotope-labelled zeatin and its derivatives at side chain.Contribution No. 1064, Alberta Research CouncilProcess for the Preparation oftrans-3-formylbut-2-enenitrile S. Chen and J. MacTaggart, patent applicatioin registered in Canada and the United States of America.Acknowledgment. The author thanks Mr J. M. MacTaggart and Mrs C. M. Goulet for valuable experimental assistance and Dr R. M. Elofson for helpful discussions.     

Effect of an ecdysteroid on DNA synthesis,DNA polymerase α and thymidine kinase activities ofDrosophila melanogaster cells in vitro

Summary 10^–7 M 20-OH-ecdysone treatment of a diploidDrosophila clone results in an inhibition of 60% of the DNA synthesis from 18 h of treatment on. After 48 h of hormone treatment the thymidine kinase activity is 70% inhibited; concomitantly a 60–70% lowering of the acid-soluble specific activity is observed. In the meantime the DNA polymerase activity is reduced.     

Rauwolfia alkaloids XLVII isoreserpiline-ψ-indoxyl,its isolation,synthesis and structure

Zusammenfassung Isoreserpiline--indoxyl wurde ausRauwolfia vomitoria Afzel isoliert. Durch eine einfache Synthese, ausgehend von Reserpilin, wurde die Struktur dieses neuen Alkaloids bewiesen.     

Tumor necrosis factor-α inhibits collagen synthesis in human and rat granulation tissue fibroblasts

The purpose of the study was to examine the effects of tumor necrosis factor- (TNF-) on collagen gene expression in rat and human granulation tissue fibroblast cultures. The cells were exposed to 0.1, 1, 10, or 100 ng/ml of TNF-, and the rate of collagen synthesis was measured as synthesis of protein-bound³H-hydroxyproline. Total cellular RNA was isolated from fibroblasts, and measurements of specific cellular RNAs from fibroblasts were performed by Northern blot hybridizations using³²P-labeled cDNA probes. In cultures of rat granulation tissue fibroblasts TNF- decreased³H-hydroxyproline production to about 75% of that in controls and it also decreased pro1(I) and pro1(III) collagen mRNA levels, maximally to 33% and 23% of the control levels, respectively. In cultures of human granulation tissue fibroblasts a similar inhibiting effect in the production of collagen was seen. TNF- decreased the production of³H-hydroxyproline to 56% of the control value with a dose of 100 ng/ml also having an inhibiting effect on pro1(I) collagen mRNA levels of up to 43% of the control level. However, no effect was seen on pro1(III) collagen mRNA levels.     

Activation ofα-carbons of amides

Summary The reactions of Vilsmeir complexes of amides/imides with electrophiles afford the corresponding -substituted products in good yield.     

Influence of the structure of theN-terminal extremity ofα-MSH on the melanophore stimulating activity of this hormone

Zusammenfassung Drei strukturelle Analoge des-MSH wurden synthetisiert und auf ihre Melanophoren-stimulierende Wirksamkeit untersucht. Für das Auftreten einer ausgeprägten biologischen Aktivität scheint die Anwesenheit einerN-Acetyl-Gruppe an dem Aminoende der Peptidkette wichtiger zu sein als das Vorhandensein der zwei ersten amino-endständigen Aminosäurereste der-MSH-Kette.