Enzymatic synthesis of melatonin in avian pineal body: extraretinal response to light

In the chick pineal body, activity of the melatonin-forming enzyme hydroxyindole-O-methyl transferase is greater in the light than in darkness. Neither bilateral enucleation of the eyes nor sympathetic denervation prevented this light-induced elevation of enzyme activity. This fact indicates that in the bird, in contrast to mammals, neither the retinas nor sympathetic innervation of the pineal body are essential for environmental control of melatonin formation.     

Superluminal and slow light propagation in a room-temperature solid

We have observed both superluminal and ultraslow light propagation in an alexandrite crystal at room temperature. Group velocities as slow as 91 meters per second to as fast as -800 meters per second were measured and attributed to the influence of coherent population oscillations involving chromium ions in either mirror or inversion sites within the crystal lattice. Namely, ions in mirror sites are inversely saturable and cause superluminal light propagation, whereas ions in inversion sites experience conventional saturable absorption and produce slow light. This technique for producing large group indices is considerably easier than the existing methods to implement and is therefore suitable for diverse applications.     

Field measurements of CO2 enhancement and climate change in natural vegetation

It is generally assumed that healthy, natural ecosystems have the potential to sequester carbon under favorable environmental conditions. There is also evidence that CO₂ acts as a plant fertilizer. It is of interest to know if these assumptions are valid and how natural systems might respond under future scenarios of CO₂ increase and possible climate changes. Few measurements of the effects of CO₂ and global climate change have been made on “natural” ecosystems under realistic field conditions. Most measurements have been conducted in the synthetic environments of totally controlled greenhouses and growth chambers. Several lines of evidence indicate that controlled environment studies using plants growing in pots induce experimental artifacts that reduce confidence in the use of results for prediction of future global responses. Open top chambers are being used in several autecological field studies in an attempt to obtain more realistic field environments. A few field microcosm studies have been completed and a system for the free air release of CO₂ has been applied in cotton fields. Unfortunately, the requirement of large amounts of CO₂ and financial restrictions have precluded the initiation of larger scale field studies in natural vegetation. This paper lists and summarizes the best field studies available but draws heavily on studies from artificial environments and conditions in an attempt to summarize knowledge of global environmental change on forests and other non-agricultural ecosystems. Finally the paper concludes that there is a need for the development and application of equipment for field measurements in several representative natural ecosystems and makes specific recommendation of the creation of a tropical research center.     

Novel trisaccharide fatty acid ester identified from the fruits of Morinda citrifolia (Noni)

Two known glycosides and a novel trisaccharide fatty acid ester were isolated from the n-butanol-soluble fraction of the fruits of Morinda citrifolia (noni). Structure determination was carried out by spectral techniques such as MS, IR, NMR, and 2D-NMR. The novel trisaccharide fatty acid ester was elucidated as 2, 6-di-O-(beta-D-glucopyranosyl)-1-O-octanoyl-beta-D-glucopyranose. The known compounds were identified as rutin and asperulosidic acid.