Influence of PGA1 on cartilage growth

Summary Using the Fell technique of organ culture of cartilage in a chemically defined medium, it has been shown that prostaglandin A₁ at a concentration of 25 g/ml caused chondrocyte death in chick embryonic limb rudiments. An equimolar concentration of PGE₂ was not toxic to the cells.Acknowledgments. We are grateful for the support of C. J. K. by the Medical Research Council and of D. L. G. by the Arthritis and Rheumatism Council for Research. Our thanks are due to Dame Honor Fell, F. R. S. for invaluable advice and guidance, to Dr J. Pike (Upjohn Co.) for supplies of prostaglandin A₁, and to Dr Sylvia Fitton-Jackson for the gift of culture medium.     

Starfish saponins. Part 101. Further 24-O-glycosidated steroids from the starfishHacelia attenuata

Summary On the basis of comparative spectral data, the structures of 3 novel steroidal glycosides from the Mediterranean starfishHacelia attenuata have been elucidated as3, 4 and5. These are further examples of a novel group of 24-O-glycosidated steroids recently encountered in the same species and in the Pacific speciesProtoreaster nodosus.Part 9. L. Minale, C. Pizza, R. Riccio and F. Zollo, Experientia39 (1983) 567. This contribution is part of the Progetto Finalizzato Chimica fine e secondaria del C.N.R., Roma.Acknowledgments. We thank Prof. K. Nakanishi, Columbia University, New York, for FD-mass spectral analyses, the Centro Interfacoltà di Metodologie Chimico-Fisiche for 270 MHz NMR facilities, and Miss R. Aquino for part of the experimental work.     

Ferredoxin reductase catalyzes styrene oxidation to styrene oxide

Summary The flavoprotein ferredoxin reductase catalyzed the oxidation of styrene to styrene oxide in the presence of NADPH. This reaction was inhibited by the addition of catalase and superoxide dismutase. The addition of the nonheme iron protein ferredoxin partially inhibited styrene oxidation. H₂O₂ was also able to catalyze this reaction when added to the enzyme in the absence of NADPH.Acknowledgments. This work was supported by C.N.R. (National Research Council), Rome, Italy contract No. 79.03197.04.     

Structural transformation reactions of anthocyanins

Summary Spectroscopic evidence shows that the flavylium cation (1) undergoes hydroxylation to form the carbinol base (2) and can also deprotonate to form the anhydro (quinonemethane) bases (3a and3b). The anhydro bases hydrate to the carbinol base. The carbinol base above pH 6, or the ionzed carbinol base (2a), undergoes diring fission to produce the cischalcone (4).The editors do not hold themselves responsible for the opinions expressed in the authors' brief reports. — Les auteurs sont seuls responsables des opinions exprimées das ces brèves communications. — Für die Kurzmitteilungen ist ausschliesslich der Autor verantwortlich. — Per le brevi comunicazioni è responsabile solo l'autore. — ë . — Solo los autores son responsables de las opiniones expresadas en estas comunicationes breves.Acknowledgment. This research was supported by a grant from the Welch Food Co., Westfield, NY.     

Birefringence signals and tension development in single frog muscle fibres at short stimulus intervals

Summary The early large birefringence signal and mechanical activity were studied together in isolated single fibres of frog skeletal muscle with double stimulation at short stimulus intervals (2–60 msec) at room temperature and at 4–6°C. In all fibres tested, extra tension and additional birefringence signal in response to the second stimulus appeared simultaneously and suddenly upon increasing the stimulus interval. The shape of the stimulus-interval versus tension-development curve makes it highly improbable that subthreshold calcium release occurs at shorter stimulus intervals; therefore, tension development reliably reflects Ca-release in these experiments. In contrast to the report by Suarez-Kurtz and Parker, birefringence signal and calcium release are shown not to be dissociated by double stimulation. This result supports the hypothesis that the early large birefringence signal is an intrinsic indicator of calcium release from the sr during EC-coupling in skeletal muscle.     

Field bioassay of male Douglas-fir beetle compound 3-methylcyclohex-3-en-1-one

Summary Synthetic 3-methylcyclohex-3-en-1-one, or 3,3-MCH, decreased by 77% the flight aggregation ofDendroctonus pseudotsugae (Scolytidae) to sticky traps containing attractant (frontalin, -pinene, and resin). However, windthrown trees were protected by 3,3-MCH much less than is known to occur with the isomer 3,2-MCH.This research was supported in part by NSF grants BMS 72-02522 and DEB 77-11361 and the O.S.U. School of Forestry. We thank the administration of the Siuslaw National Forest for study sites, and Dr L.M. Libbey for GC/MS of 3,3-MCH. Oregon State University Ag. Exp. Sta. Tech. Paper No. 4313.     

The effect of acidic polysaccharides and prostaglandin-like substances isolated from Propionibacterium acnes on granulocyte chemotaxis.

Three acidic polysaccharide (AP) fractions and the prostaglandin-like substances (PLS) isolated from P. acnes were investigated regarding their chemotactic activities on polymorphonuclear leukocytes. Both AP's and PLS induced a significant chemotatic response, which suggests their involvement in inflammatory acne vulgaris.     

PPD-induced blastogenesis is auto-regulated by suppressor cells generated in vitro.

Suppressor cell induction can be demonstrated during antigen specific blastogenesis by using the same methods which have shown induction of suppressor cells by Con A. Since suppressor cells are rapidly generated during antigen specific blastogenesis, they must regulate the final level of blastogenesis induced during the seven day in vitro incubation.     

A rotating bottle culture method with continuous replacement of the gas phase

Summary A rotator culture method is described which provides a continuous flow of oxygenating gas to cultures in rotating bottles. The system maintains constant O₂ and CO₂ levels in the culture medium throughout the incubation period. It also provides a more stable pH than systems with sealed culture bottles.Acknowledgments. We would like to thank Mr B. Secker, Mr C. Hellon and Mr S. J. Ellis, of the Physiological Laboratory workshop, for constructing the rotator apparatus. We also thank the Medical Research Council, London, for financial support for the project.     

In vitro inactivation of corpora allata of the bugOncopeltus fasciatus by precocene II

Summary Corpora allata fromOncopeltus fasciatus incubated in vitro in medium containing 10^–5.35 M (1 g/ml) of precocene II lose their ability to secrete juvenile hormone when reimplanted into last instar larvae.Acknowledgments. We thank Mr K. Dorn, Mrs L. Dolezal, Mrs V. Nötzli-Graf, Mr K.H. Trautmann and Mr A. Schuler for technical help, Dr W. Vogel and Dr A. Dübendorfer for valuable discussions.