Paternal allocation of sequestered plant pyrrolizidine alkaloid to eggs in the danaine butterfly,Danaus gilippus

Summary Pyrrolizidine alkaloid sequestered by adult maleDanaus gilippus from plants is transferred in large measure to the female at mating, and by the female to the eggs. The eggs, presumably, are protected as a result. The male's courtship pheromone, danaidone, derived from the sequestered alkaloid, may function to advertise the male's alkaloid-donating capacity.Acknowledgments. Paper Nr. 89 of the series Defense Mechanisms of Arthropods. Study supported by NIH (Grants AI-02908 and AI-12020; Predoctoral Traineeship to DED), Hatch funds (191-7416), the Bache Fund (National Academy of Sciences, to DED), and the Theodore Roosevelt Memorial Fund (American Museum of Natural History, to DED). We thank M. Weingarner and J. Miller forD. gilippus collection, J. Boggan for technical assistance, and the staff of the Archbold Biological Station, Lake Placid, Florida, for assistance and hospitality. One of us (DED) is indebted to M. D. Achey, who by demonstrating nuptial cardenolide transfer in the monarch butterfly [Honors Thesis, Amherst College, Amherst, Massachusetts (1979)] raised the possibility that other plant metabolites might be similarly transferred in danaines.Deceased July, 1985. This paper is affectionately dedicated to his memory.     

Mitochondrial derivation of centrioles in some endocrine adenomas

Summary Fine structural studies of various endocrine adenomas indicate that mitochondria may serve as progenitors of centrioles and cilia.Acknowledgments. This work was supported in part by a grant from the Ontario Cancer Treatment and Research Foundation. The excellent technical assistance of Mrs.Gezina Ilse and the secreterial help of Mrs.Wanda Mikitson are gratefully acknowledged.     

The rate of cleavage ofβ-mercaptopyruvate by rapidly dividing cells

Zusammenfassung Quantitative Analysen des-mercaptobrenztraubensäure-spaltenden Enzyms zeigen, dass Zellen, die sich in aktivem mitotischem Prozess befinden (bzw. Krebszellen und Gewebekulturen), dieses Enzym in viel geringerem Masse enthalten als « normale » Zellen. Da dieses Enzym in dem anaeroben Stoffwechsel von Zystein eine wichtige Rolle spielt, lässt sich vermuten, dass sich der Zysteinstoffwechsel der Tumorzelle quantitativ von dem der Normalzelle unterscheidet.

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Supported by U.S. Public Health Grants H-2897, C-3211 and by a grant of the American Cancer Society (70-4612-24).     

Prostaglandin-like substances inPropionibacterium acnes. IV. Effect on isolated human vessels

Summary The present study demonstrates a powerful vasoconstrictor activity of prostaglandin-like substances (PLS), extracted fromP. acnes, on human blood vessels. PLS is about equipotent to PGE₂ in its effect on human umbilical vessels, but the contractile response pattern is different. PLS therefore seems to have specific and different physiological characteristics.     

A study on the effects of some drugs on DOCA induced hypertension in the rat

Chronic treatment with various drugs reduced the increase in arterial blood pressure, the ventricular hypertrophy and the thickening of pulmonary arterial and arteriolar walls.     

Activation of stress signalling pathways enhances tolerance of fungi to chemical fungicides and antifungal proteins

Fungal disease is an increasing problem in both agriculture and human health. Treatment of human fungal disease involves the use of chemical fungicides, which generally target the integrity of the fungal plasma membrane or cell wall. Chemical fungicides used for the treatment of plant disease, have more diverse mechanisms of action including inhibition of sterol biosynthesis, microtubule assembly and the mitochondrial respiratory chain. However, these treatments have limitations, including toxicity and the emergence of resistance. This has led to increased interest in the use of antimicrobial peptides for the treatment of fungal disease in both plants and humans. Antimicrobial peptides are a diverse group of molecules with differing mechanisms of action, many of which remain poorly understood. Furthermore, it is becoming increasingly apparent that stress response pathways are involved in the tolerance of fungi to both chemical fungicides and antimicrobial peptides. These signalling pathways such as the cell wall integrity and high-osmolarity glycerol pathway are triggered by stimuli, such as cell wall instability, changes in osmolarity and production of reactive oxygen species. Here we review stress signalling induced by treatment of fungi with chemical fungicides and antifungal peptides. Study of these pathways gives insight into how these molecules exert their antifungal effect and also into the mechanisms used by fungi to tolerate sub-lethal treatment by these molecules. Inactivation of stress response pathways represents a potential method of increasing the efficacy of antifungal molecules.     

On the biosyntheses of artemisia ketone and bakuchiol

Summary New biosynthetic pathways for the irregular terpenes, artemisia ketone and bakuchiol, are proposed. It is suggested that 2-(1-hydroxy-3-methylbutyl)thiamine and 2-(1-hydroxy-2-phenylethyl) thiamine are key intermediates in the biosyntheses of artemisia ketone and bakuchiol, respectively.