Expression of cadherin10, a type II classic cadherin gene, in the nervous system of the embryonic zebrafish

Cadherins are cell surface adhesion molecules that play important roles in development of tissues and organs. In this study, we analyzed expression pattern of cadherin10, a member of the type II classic cadherin subfamily, in the embryonic zebrafish using in situ hybridization methods. cadherin10 message (cdh10) is first and transiently expressed by the notochord. In the developing nervous system, cdh10 was first detected in a subset of the cranial ganglia, then in restricted brain regions and neural retina. As development proceeds, cdh10 expression domain and/or expression levels increased in the embryonic nervous system. Our results show that cdh10 expression in the zebrafish developing nervous system is both spatially and temporally regulated.     

The Effects of EPA,DHA, and Aspirin Ingestion on Plasma Lysophospholipids and Autotaxin

Lysophophatidylcholine (LPC) and lysophosphatidic acid (LPA) are potent lysolipid mediators increasingly linked with atherosclerosis and inflammation. A current model proposing that plasma LPA is produced when LPC is hydrolyzed by the enzyme autotaxin has not been rigorously investigated in human subjects. We conducted a clinical trial of eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA) and aspirin ingestion in normal volunteers. Fasting blood samples were drawn at baseline and after 4-week supplementation with EPA/DHA (3.4 g/d) with and without aspirin (650 mg). Plasma LPC and LPA species and autotaxin activity were measured. EPA-LPC and DHA-LPC concentrations increased significantly with EPA/DHA supplementation whereas EPA- and DHA-LPA did not. Autotaxin activity was unaffected by any treatment, and aspirin had no effect on any endpoint. Taken together, our data demonstrate that plasma LPC, but not LPA, species can be dynamically regulated by dietary supplementation, and argue against a simple model of LPA generation via LPC hydrolysis.     

Anticodon-dependent aminoacylation of RNA minisubstrate by lysyl-tRNA synthetase.

Specific inhibition of mammalian lysyl-tRNA synthetase by polyU is shown. Inhibition of the enzyme is dependent on the length of the oligonucleotide, since oligoU molecules with a length of less than 8 residues do not inhibit the aminoacylation, whilst the effect of oligoU molecules with a length of about 30 residues is the same as that of polyU. Inhibition is a result of recognition by the enzyme of the tRNALys anticodon sequence (UUU) coded by polyU. Aminoacylation of the oligoU molecule with attached CCA sequence (G(U)20-CCA) by yeast and mammalian lysyl-tRNA synthetases is demonstrated.     

Reproductive Phenology of Woody Species in a North Australian Tropical Savanna1

Interspecific and interannual variation in reproductive phenology was quantified for 50 common species of trees and shrubs from a mesic savanna near Darwin, northern Australia. The presence of buds, flowers, and fruit was noted over a 30-month period, from September 1992 to February 1995. Surveys were undertaken at monthly intervals for the less common species, and at bimonthly intervals for ten of the common trees and tall shrubs. The majority of species flowered each year at about the same time. There was no evidence of sub-annual or continuous regimes of reproductive phenology. There was no supra-annual carryover of seed-bearing fruit in the canopy of any species. The peak flowering periods were the mid to late dry season (July–August) and the transition between the dry season and the wet season (October–November). The two dominant trees–Eucalyptus miniata and E, tetrodonta– flowered during the dry season, thereby providing resources for some elements of the vertebrate fauna. Flowering and fruiting were uncommon at the end of the wet season (February/March), although two species that flower and fruit at this time (E. porrecta and Terminalia ferdinandianas may provide resources to consumers at a time when floral or fruit resources are otherwise scarce. Because the peak of reproductive activity takes place during the late dry season, fruit maturity and seed dispersal have occurred prior to the onset of the rainy season for most species, and germination and seedling establishment potentially may take effect in response to the first rains. Late dry season fires, which tend to be extensive and intense, are a potential threat to the floral and fruit reserves within these savannas.