Towards quantification of vocal imitation in the zebra finch

The transition from an amorphous subsong into mature song requires a series of vocal changes. By tracing song elements during development, we have shown that the imitation trajectory to the target could not be predicted based on monotonic progression of vocal changes, indicating an internal component that imposes constraints on song development. Here we further examine the nature of constraints on song imitation in the zebra finch. We first present techniques for identifying and tracing distinctive vocal changes, and then we examine how sequences of vocal change are expressed and coordinated. Examples suggest two types of constraints on song imitation, based on the nature of the temporal context. Developmentally diachronic constraints are imposed by sequential dependencies between vocal changes as a function of developmental time, whereas developmentally synchronic constraints are given by the acoustic context of notes within the song. Finally, we show that the tendency of birds to copy certain sounds in the song model before others might be related to such constraints. We suggest that documenting the full range of distinctive vocal changes and the coordination of their expression would be useful for testing mechanisms of vocal imitation.     

PYCNOGENOL chewing gum minimizes gingival bleeding and plaque formation.

PYCNOGENOL is an antioxidant phytochemical shown to have antiinflammatory activity in both the in vitro and in vivo models. This study compared the effects of chewing gums with and without PYCNOGENOL on gingival bleeding and plaque formation in 40 human subjects. In this double-blind study, subjects were assigned randomly to receive either control gums without PYCNOGENOL or experimental gums containng 5 mg PYCNOGENOL. Subjects used chewing gums for 14 days. Gingival bleeding and plaque scores were taken before and after the experiment. PYCNOGENOL chewing gums significantly reduced gingival bleeding, while no changes were noted in bleeding indexes in control subjects who used regular chewing gums. Subjects using regular control gums had significant increases of dental plaque accumulation during the two-week period. No increases in plaque accumulation were noted in subjects using PYCNOGENOL chewing gums. The data of this study suggest that the use of Pycnogenol chewing gums can minimize gingival bleeding and plaque accumulation.     

The exosome of Trypanosoma brucei.

The yeast exosome is a complex of at least 10 essential 3'-5' riboexonucleases which is involved in 3'-processing of many RNA species. An exosome-like complex has been found or predicted to exist in other eukaryotes but not in Escherichia coli. The unicellular parasite Trypanosoma brucei diverged very early in eukaryotic evolution. We show here that T.brucei contains at least eight exosome subunit homologs, but only a subset of these associate in a complex. Accordingly, the T.brucei exosome is smaller than that of yeast. Both free and complex-associated homologs are essential for cell viability and are involved in 5.8S rRNA maturation. We suggest that the exosome was present in primitive eukaryotes, and became increasingly complex during subsequent evolution.     

Low responsiveness of six-rowed genotypes to androgenesis in barley does not have a pleiotropic basis.

A heterozygous mutant for the two- and six-rowed character was isolated in the barley cultivar Igri through application of sodium azide to isolated microspore cultures and posterior regeneration. Six-rowed and two-rowed homozygotic plants were subsequently identified in the self-pollinated M2 progenies of the original heterozygous M1. Detailed molecular markers confirmed the isogenic nature of this recovered mutant and the original cultivar Igri. A comparative study of the anther culture response of this six-rowed induced mutant vs. diploid 'Igri' was performed to assess whether the two- or six-rowed gene influences anther culture response in barley through a pleiotropic effect or via linkage disequilibrium. No significant differences for any of the recorded variables throughout the in vitro regeneration process were detected between the 'Igri' six-rowed mutant and any of their two-rowed isogenic lines. This suggests that row-type association with anther culture response in barley cultivars is due to the effect of a tight linkage with other genes directly responsible for androgenic response.     

Simple, reliable and fast spectrofluorometric method for determination of plasma Verteporfin (Visudyne) levels during photodynamic therapy for choroidal neovascularization.

Photodynamic therapy with Verteporfin, a potent photosensitizer dye, is a very effective treatment for age related macular degeneration due to choroidal neovascularization. Photodynamic therapy offers the potential for selective tissue injury in part attributable to preferential localization of Verteporfin, administrated by intravenous infusion, to the choroidal neovascularization complex and irradiation of the complex with non-laser thermal light at 690 nm resulting in at least temporary thrombosis and vessel closure. Verteporfin is a benzoporphyrin derivative monoacid ring A formulated as a unilamellar liposome. In the blood Verteporfin is associated with lipoprotein fractions and is rapidly cleared via a receptor-mediated uptake mechanism due the high expression of LDL receptors in neovascular tissues. Verteporfin was undetectable in plasma 24 hr after infusion of the recommended dose: 6 mg/m2 of body surface area. The main side effect is photosensitivity of skin which is usually short-lived (24-48 hr) with a low incidence (2.3%). As skin photosensitivity depends on circulating rather than tissue drug levels, we investigate the possibility of developing a simple, fast and reliable spectrofluorometric method to measure plasma Verteporfin levels. Fluorescence emission spectrum (550-750 nm) of 1:10 saline diluted plasma with lambda exc=430 nm showed a characteristic emission peak at 692 nm, the height being proportional to the Verteporfin levels. The sensitivity is around 100 ng/ml and the pharmacokinetics of Verteporfin has been studied from 0 to 5 hr after infusion in six patients older than 65 years with age-related macular degeneration.     

Active compounds in Populus nigra L. wilted leaves responsible for attracting Helicoverpa armigera (Hübner) (Lep., Noctuidae) and new agaropectin formulation

Abstract:  The leaf extracts of Populus nigra were collected and identified by steam distillation, air entrainment and gas chromatographic–mass spectrometric analysis. Electroantennograms were recorded from Helicoverpa armigera adults in response to the chemicals identified. Both aromatic compounds and green-leaf volatiles elicited strong responses. Field experiments revealed that the active compounds responsible for attracting H. armigera moths are mainly short-side-chain aromatic alcohols and aldehydes. We, for the first time, used agaropectin as the controlled-release matrix of insect attractants. A five-component lure containing all the aromatics without phenolics, mixed in the proportions as found in the steam distillate of the leaves collected in August, produced the best trap catch. The results showed that the volatiles of wilted leaves of P. nigra can attract H. armigera adults by feeding attraction.