Expression of human pituitary adenylate cyclase activating polypeptide (PACAP) cDNA in CHO cells and characterization of the products.

cDNA encoding human PACAP precursor was expressed in non-neuroendocrine Chinese hamster ovary cells, CHO-K1, The cells were transfected with expression vector (pTS705) containing the human PACAP cDNA by electroporation. A cell line which produced more than 80 ng/ml of immunoreactive PACAP (ir-PACAP) into the conditioned medium was established. RP-HPLC analysis of culture medium of this established cell line exhibited the presence of two types of PACAP, i.e. PACAP38 and PACAP27. At the same time, it was also revealed that immunoreactive PACAP-related peptide (ir-PRP) was secreted into the cultured medium. The ir-PACAPs were confirmed to ahve biological activities such as induction of cAMP and neurite outgrowth in rat pheochromocytoma PC12h cells.     

Plant Traces Resembling Skolithos

The ichnogenus Skolithos Haldeman 1840 is a simple tubular trace fossil that was initially described as a “fucoid” or seaweed impression, i.e., a fossilized marine plant. Today the tracemaker is commonly considered to have been a vermiform marine invertebrate, although this interpretation is not acceptable to all. It is the name giver to the archetypal, Seilacherian Skolithos ichnofacies, which is a widely acknowledged indicator of relatively high energy, shallow water, nearshore to marginal marine environments. Here we record and describe analogous cylindrical structures, unquestionably reflecting plant tracemakers. These have been recognized in Quaternary consolidated “coffee” sandrock and Recent coastal dune, marsh or swamp, and salt meadow settings from northern New Zealand and Sapelo Island, USA.

We conclude that Skolithos is not an unequivocal indicator of shallow marine settings. Our observations confirm the opinions of a number of previous workers who have expressed the need for caution when using this ichnotaxon as a shallow-water, higher energy palaeoenvironmental indicator, especially when supporting evidence is otherwise lacking. In particular we note that in high intertidal and non-aquatic settings, Skolithos may be a plant trace fossil rather than serve as evidence for invertebrate activities. At the present time there is pressing need for a thorough systematic revision of the Skolithos ichnotaxon.     

Solution conformation of endothelin determined by nuclear magnetic resonance and distance geometry

The solution conformation of endothelium-derived vasoconstrictor peptide, endothelin, has been determined by two-dimensional 1H-NMR spectroscopy and distance geometry. Conformation in the N-terminal core region (residues 1-15) is well-defined and a characteristic is the helix-like conformation in the segment from Lys9 to Cys15. Contrarily, the C-terminal tail region (residues 16-21) does not assume a defined conformation and there are no specific interactions between the core and the tail regions.