Immunoprophylaxis of respiratory syncytial virus: global experience

In sarcoidosis, host genetic factors are discussed as contributing to disease susceptibility and course. Since tumor necrosis factor (TNF)-α is a central mediator of granuloma formation and since elevated TNF-α levels are found during active phases of sarcoidosis, genetic polymorphisms correlating with influences on TNF-α levels are of special interest. The complete sequencing of the MHC region and the increase in the number of identified gene polymorphisms in this locus associated with TNF-α production offer the opportunity of detecting new genes associated with sarcoidosis and perhaps of defining disease-associated haplotypes that bear the potential of serving as predictive markers for this disease.     

1-substituted cyclopropenes: Effective Blocking Agents for Ethylene Action in Plants

A series of 1-alkane substituted cyclopropenes has been prepared and tested as ethylene antagonists using banana fruits as an assay system. 1-Methyl-, 1-ethyl-, 1-propyl-, 1-butyl-, 1-pentyl-, 1-hexyl-, 1-heptyl-, 1-octyl-, 1-nonyl-, and 1-decylcyclopropene were all very active compounds. 1-Methylcyclopropene protected bananas from ethylene with a minimum concentration of 0.7 nl.l^–1 after a 24 h exposure. As the carbon chain length was extended the minimum requirement increased some, but starting with 1-butylcyclopropene, the minimum concentration requirement declined and many cyclopropenes were required in lower concentrations than 1-methylcyclopropene. The time of protection at ambient temperature (22–23 °C) was 12 d for 1-methyl-, 1-ethyl-, 1-propyl-, and 1-butylcyclopropene. 1-Pentylcyclopropene protected bananas for 14 d, 1-hexylcyclopropene for 20 d, 1-heptylcyclopropene for 21 d, 1-octylcyclopropene for 25 d, 1-nonylcyclopropene for 35 d, and 1-decylcyclopropene for 36 d.     

Effect of Ethylene on Cell Division and Deoxyribonucleic Acid Synthesis in Pisum sativum

Ethylene and supraoptimal levels of 2,4-dichlorophenoxyacetic acid inhibit the growth of the apical hook region of etiolated Pisum sativum (var. Alaska) seedlings by stopping almost all cell divisions. Cells are prevented from entering prophase. The hormones also retard cell division in intact root tips and completely stop the process in lateral buds. The latter inhibition is reversed partially by benzyl adenine. In root tips and the stem plumular and subhook regions, ethylene inhibits DNA synthesis. The magnitude of this inhibition is correlated with the degree of repression of cell division in meristematic tissue, suggesting that the effect on cell division results from a lack of DNA synthesis. Ethylene inhibits cell division within a few hours with a dose-response curve similar to that for most other actions of the gas. Experiments with seedlings grown under hypobaric conditions suggest that the gas naturally controls plumular expansion and cell division in the apical region.     

Orexin A effects on the olfactory bulb spontaneous activity and odor responsiveness in freely breathing rats

The mitral cells (MCs) of the olfactory bulb (OB) are relay neurons between the periphery and the central nervous structures. MCs receive in turn a centrifugal control from several higher brain centers that depends on the nutritional state. In this study, we investigated the effects of orexin A (ORX), a novel molecule known to regulate food intake and whose receptors are present in the OB, on the electrophysiological activity of single MCs. Using icv-injections and direct applications on the OB, we determined the respective central and local effects of this molecule on the MCs' spontaneous firing activity and responsiveness to different odors. Icv-injections and local OB-applications were found to induce a significant decrease in spontaneous firing activity in 14% and 50% of the recorded MCs, respectively. In one case, ORX application on the OB caused a significant firing increase. Effects of OB-applications had shorter delays. The responsiveness of some MCs to food and non-food odors was also changed, but the proportion of changes was not statistically significant. Icv-injection effects likely resulted from a local action of ORX on the OB. Changes of spontaneous firing activity and odor responsiveness are discussed in terms of regulation of the functioning of the olfactory system.     

Reduction in Extractable Deoxyribonucleic Acid Polymerase Activity in Pisum sativum Seedlings by Ethylene

An extract from the apical portion of etiolated seedlings of Pisum sativum L. was used as a test system to examine the action of ethylene on DNA polymerase activity. The extract catalyzed the polymerization of labeled deoxyribonucleoside triphosphates into a trichloroacetic acid-insoluble product. The system required Mg²⁺, nicked DNA, and all four deoxyribonucleoside triphosphates for maximum activity. Extracts from plants previously treated with ethylene showed less activity to synthesize DNA than extracts from nontreated plants. Loss of extractable DNA polymerase activity may be due to accumulation of a non-competitive inhibitor in the ethylene-treated plants. Treating the extract with ethylene did not affect the polymerase activity. Inhibition of cell division by ethylene observed in this and other tissues may be the result of accumulation of an inhibitor of DNA polymerase.     

The novel ethylene antagonist, 3-cyclopropyl-1-enyl-propanoic acid sodium salt (CPAS), increases grain yield in wheat by delaying leaf senescence

Orchid is a major floral crop around the world and Dendrobium hybrids are considered to be one of the most popular orchids. In vitro germination of hybrid seeds is a common practice among orchid growers, however, in many cross pollinations the embryos may not develop to maturity, leading to poor seed germination. The effect of seed maturity and sucrose concentration were investigated via asymbiotic germination of nobile Dendrobium hybrids. Capsules were harvested from two hybrids (Den. Lucky Girl × Den. Second Love ‘Kirameki’ and Den. Lucky Girl × Den. Hamana Lake ‘Kumi’) and one selfing of Den. Second Love ‘Kirameki’ at 2, 3, 4, and 5 months after pollination and immature seeds were taken. Immature seeds from 3- to 5-month old capsules could be successfully germinated on Hyponex based medium. Immature seeds from 4-month old capsules showed greatest germination rate of tested treatments, whereas 3-month old immature seeds showed the least germination. After 6 weeks of in vitro culture, protocorms derived from embryos developed on every concentration of sucrose, but germination was greater at lower concentrations. Greater concentration of sucrose decreased normal-developed protocorms.