Biological effects of singlet delta oxygen on respiratory tract epithelium

Summary Exposure of hamster tracheal organ cultures to gas phase singlet delta oxygen,¹O₂, at atmospheric pressure produced significant alterations in the mucociliary epithelium resulting in changes in ciliary activity and cellular morphology.Acknowledgments. The authors acknowledge helpful conversations with Professor R.W. Murray of the University of Missouri (St. Louis). We would like to thank the National Institute of Environmental Health Sciences for supporting this work through Public Health Grant 1-RO1-ESO1-O1A1-PHTB.     

Biological effects of singlet delta oxygen on respiratory tract epithelium

Exposure of hamster tracheal organ cultures to gas phase singlet delta oxygen, O2, at atmospheric pressure produced significant alterations in the mucociliary epithelium resulting in changes in ciliary activity and cellular morphology.     

Inhibition of firefly bioluminescence by scavengers of singlet oxygen,superoxide radicals and hydroxyl radicals

Summary The participation of highly energetic oxygen species in the ATP-induced bioluminescence of a firefly-extract has been investigated. The inhibition of light emission by a variety of specific scavengers suggests that singlet oxygen, superoxide radicals and hydroxyl radicals are important intermediates in the firefly bioluminescence reaction.Acknowledgments. I thank Prof. R. Bachofen, Institut für Allgemeine Botanik, Abteilung Mikrobiologie, Universität Zürich, Switzerland, in whose laboratory most of these studies have been performed, for his cooperativity. Financial support by the Deutsche Studienstiftung is gratefully acknowledged.     

Energy transfer from the second excited singlet state of spirobifluorene

Summary Energy transfer from the second excited state of spirobifluorene is examined by polarization spectroscopy. Evidence against spiroconjugation and evidence in favor of a coulombic mechanism is reviewed and discussed. This coulombic interaction is categorized as an intramolecular energy transfer caused by the extrinsic factors of the Weber nomenclature.     

Myosins from plants

Molecular cloning and sequence analysis of myosin genes from Arabidopsis thaliana and electron microscopic observation of a myosin from characean alga have revealed that overall structure of plant unconventional myosins is similar to that of the class V myosins. These plant unconventional myosins have two heads, a coiled-coil tail of varied length and a globular tail piece at the end. The tail piece is probably a site for membrane interaction. Characean myosin is of special interest because it can translocate actin filaments at a velocity several times faster than muscle myosin, which must have evolved to support the quick movement of animals in the struggle for their lives.     

Effects of scavengers of superoxide radicals,hydrogen peroxide,singlet oxygen and hydroxyl radicals on malondialdehyde generation from arachidonic acid by bovine seminal vesicle microsomes

Summary Superoxide dismutase, catalase and sodium formate did not inhibit the formation of malondialdehyde (MDA) from arachidonic acid, suggesting that O ₂ , H₂O₂ and OH^. are not involved in the enzymatical oxidation of arachidonic acid. Sodium azide was found to be an inhibitor of MDA production.     

Effects of scavengers of superoxide radicals, hydrogen peroxide, singlet oxygen and hydroxyl radicals on malondialdehyde generation from arachidonic acid by bovine seminal vesicle microsomes

Superoxide dismutase, catalase and sodium formate did not inhibit the formation of malondialdehyde (MDA) from arachidonic acid, suggesting that O2-., H2O2 and OH. are not involved in the enzymatical oxidation of arachidonic acid. Sodium azide was found to be an inhibitor of MDA production.     

Antimutagenic unusual amino acids from plants

Five unusual amino acids were identified as antimutagens against spontaneous mutation of Salmonella typhimurium TA100: L-azetidine-2-carboxylic acid (1) from Liliaceae plants, alpha-(methylenecyclopropyl)glycine (2) from Litchi chinensis seeds, and 2-amino-4-methylhex-5-ynoic acid (3), hypoglycin A (4), and (2S,4R)-2-amino-4-hydroxyhept-6-ynoic acid (5) from Euphoria longana seeds. The absolute stereochemistry of 5 was determined by its chiral synthesis from L-allylglycine, proving that 5 is the C-4 epimer of the amino acid previously isolated from dried longan seeds.     

Antimutagenic unusual amino acids from plants

Summary Five unusual amino acids were identified as antimutagens against spontaneous mutation ofSalmonella typhimurium TA100: L-azetidine-2-carboxylic acid (1) from Liliaceae plants, -(methylenecyclopropyl)glycine (2) fromLitchi chinensis seeds, and 2-amino-4-methylhex-5-ynoic acid (3), hypoglycin A (4), and (2S, 4R)-2-amino-4-hydroxyhept-6-ynoic acid (5) fromEuphoria longana seeds. The absolute stereochemistry of5 was determined by its chiral synthesis from L-allylglycine, proving that5 is the C-4 epimer of the amino acid previously isolated from dried longan seeds.This work was partly supported by a Grant-in-Aid form the Ministry of Education, Science, and Culture, Japan, No. 57740283 (to HK).     

Airborne methyl jasmonate stimulates the biosynthesis of furanocoumarins in the leaves of celery plants (Apium graveolens)

When leaves ofApium graveolens are exposed to vapours of methyl jasmonate (MeJa) or fed through the petiole with aqueous solutions of jasmonic acid (Ja), the levels of natural furanocoumarins, in particular xanthotoxin and bergapten, are greatly increased. The induction becomes manifest after application of 20 nmol of either Meja or Ja. Levels of xanthotoxin and bergapten begin to increase approximately 24 h after application of the inducer. Maximum concentration of the two furanocoumarins (40–70 fold increase) is reached after 4–6 days. This pronounced effect of volatile MeJa on the physiological status of the celery leaf may be considered as representative of a build-up of chemical defenses, in an undamaged plant, after receipt of airborne signals from damaged or undamaged, but fragrant plants.     

Release of oxidases from the roots of plants

Summary In this paper, we report on the isolation and purification of the oxidase released from the roots ofLactuca sativa seedlings. This is the first time that the release of oxidases from the roots of plants into their rhizosphere has been reported.     

A fungitoxic principle from the leaves of lawsonia inermis lam

During antifungal screening of higher plants, the leaves of Lawsonia inermis were found to exhibit strong fungitoxicity. On chemical investigation, the antifungal factor was found to be 2-hydroxy-1,4-naphthoquinone (Lawsone). The minimum effective dose against test organism was found to be 1000 ppm. Lawsone was found to exhibit fungicidal activity, wide fungitoxic spectrum and nonphytotoxicity.     

Regeneration of plants from mesophyll protoplasts ofAtropa belladonna

Summary Isolated leaf mesophyll protoplasts ofAtropa belladonna when cultured in defined liquid culture media regenerate cell walls, divide and form calli. Subsequent induction of shoot and root organogenesis leads to plantlets which grow to maturity after transfer to soil.Acknowledgment. We are indebted to Václav Mandák for skilful technical assistance.     

A fungitoxic principle from the leaves ofLawsonia inermis Lam.

Summary During antifungal screening of higher plants, the leaves ofLawsonia inermis were found to exhibit strong fungitoxicity. On chemical investigation, the antifungal factor was found to be 2-hydroxy-1,4-naphthoquinone (Lawsone). The minimum effective dose against test organism was found to be 1000 ppm. Lawsone was found to exhibit fungicidal activity, wide fungitoxic spectrum and nonphytotoxicity.Acknowledgment. Authors are thankful to Dr Nitya Nand, Central Drug Research Institute, Lucknow, for providing facilities to carry out chemical investigations. Our thanks are particularly due to Dr R. S. Kapil, Dr Geeta Devi Tripathi and Dr S. C. Tripathi for their help rendered in various ways.     

Chemical investigations ofAlangium lamarckii II. Isolation of choline from the leaves

Zusammenfassung Nachweis des Cholinchlorid als Substanz, welche für die cholinergische Wirkung wässriger Extrakte der Blätter vonAlangium lamarckii verantwortlich ist.     

Acquisition of nutrients from organic resources by mycorrhizal autotrophic plants

Summary Evidence exists to suggest that mycorrhizal fungi are capable of producing enzymes allowing them to access carbon, nitrogen and phosphorus from complex organic resources in soil. This facility is mainly demonstrated in ectomycorrhizal and ericaceous endomycorrhizal fungi associated with highly organic soils and climatically stressed environments. These data support a direct nutrient cycling hypothesis proposed for tropical ectomycorrhizal forests. In terms of forest succession, the evidence agrees with a major contribution of the mycorrhizal symbiosis in late stages of the succession, where elemental cycling becomes increasingly more conservative and process rates limited by biotic factors. Here, tree growth benefits from direct nutrient cycling mediated by their mycorrhizal symbionts.     

Absorption and translocation of tetrachlorodibenzo-p-dioxine by plants from polluted soil

Summary Measurements were made of contamination of plants grown in soil polluted with tetrachlorodibenzo-p-dioxine. Findings show that the pollutant is absorbed and translocated by the plants studied and suggest that the pollutant may be eliminated in the course of time.Acknowledgment. This research was sponsored by the Regional Government of Lombardy, Italy. The authors would like to thank Prof. Marrè for his continuous interest and for the fruitful discussion.