Biosynthesis of the Egg-Laying Hormone (ELH) in the Bag Cell Neurons of Aplysia californica

Biosynthesis of the egg-laying hormone in the bag cell neurons of Aplysia californica was studied. Bag cells were incubated with leucine-3H in vitro for 30 min and rinsed for variable periods of time in a chase medium. The distribution of incorporated label among proteins within the cells was assayed by electrophoresis of an homogenate on sodium dodecyl sulfate polyacrylamide gels. Results from rinse times shorter than 30 min revealed that the predominant synthetic product is a 25,000 dalton protein. With longer rinse times, this species was reduced and two species of lower molecular weight became prominent. This redistribution of radioactivity was quantitative and was not prevented by inhibition of protein synthesis during the rinse. A 10°C reduction in temperature (from 15°C) blocked the redistribution. These data are interpreted to indicate that the 25,000 dalton molecule is a precursor which is cleaved enzymatically to yield two lower molecular weight products. One product is a 12,000 dalton molecule which remains in the cell bodies. The other is a molecule of <10,000 daltons which is exported from the somata into the neurohemal regions of the connective tissue. Perfusion of these regions with high [K+] medium results in the release of this product into the medium. It is concluded that this product is the 6000 dalton egg-laying hormone (ELH)

Polypeptide Secretion from the Isolated Parietovisceral Ganglion of Aplysia californica

In vitro studies of the secretory behavior of the parietovisceral ganglion in Aplysia californica were performed. The aim of these studies was to investigate the release of polypeptides in response to depolarizing stimuli, and, in particular, to determine if a specific polypeptide known to induce egg laying in the intact animal is secreted into the bathing medium. During continuous perfusion of a ganglion preincubated in leucine-3H the application of either high-potassium medium or a burst of electrical stimuli (via the pleurovisceral connective nerve) evoked a marked increase in the amount of trichloroacetic acid (TCA)-precipitable radioactivity recovered in the perfusate. Enhanced release could be detected within 80 sec of the initial exposure to high potassium; however, incubation of a ganglion in calcium-free media before the application of high-potassium medium abolished the increase of precipitable radioactivity. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of perfusate samples revealed a significant change in the polypeptide species washed from the ganglion during high-potassium depolarization. Bioassays confirmed that egg laying is induced when high-potassium medium used to bathe a ganglion is injected into a recipient animal. These and other results permit the conclusion that the bulk of the polypeptide material secreted from the ganglion in response to depolarization is a specific neurohormone produced by two identified cell clusters, the so-called bag cells

Tracking Electronic Resource Acquisitions: Using a Helpdesk System to Succeed where your ERMS Failed

From selection to license negotiation through activation, libraries need the ability to track the electronic resource acquisition process and support uninterrupted workflow through multiple people and/or departments. Existing systems store fragments of information about a resource, but they don’t support management of the progress of each resource through the electronic resource acquisition maze. Stanford and Claremont have configured the JIRA and Footprints ticketing systems to address this fundamental need. Our systems facilitate efficient and complete activation of e-resources, and allow greater transparency in the acquisitions process throughout the organization. We will demonstrate the key features & functionality of our independently configured systems and invite discussion about these critical improvements to electronic resource management systems

Consumer Storytelling of Brand Archetypal Enactments

The study here probes the perspective that consumers use certain brands as actors that play roles in the consumers’ lives and that help consumers as protagonists to enact roles that give them the feelings of achievement, well-being, and/or emotional excitement. The method enables the uncovering of archetypes as unconscious forces that drive consumers to specific actions implicitly and to a less extent, explicitly. The study employs two techniques: degrees-of-freedom analysis (DFA) to test whether or not consumer stories fit a given archetypal theme and visual narrative art (VNA) to confirm whether or not consumer’s own stories enact a specific archetype and how such enactments are done. This study offers an alternative for survey auditing consumer-brand relationships; the study here describes and explains the importance of narratives in consumer behaviour and the use of archetypes as universal themes that aid understanding of brand-consumer relationships. The study describes DFA and VNA with two examples of the use of these analytics

Larval settlement in flocculated particulates

Author Posting. © The Authors, 2008. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 66 (2008): 275-297, doi:10.1357/002224008785837167.Planktonic larval settlement can be a major determinant of population and community dynamics. Settlement templates of benthic invertebrates have been attributed to biological, chemical, and hydrodynamic mechanisms. Completely unexplored, however, is the role of patchy, but widespread, flocculated particulates (“floc”) that intermittently rest on substrate surfaces. Motivated by observations of very high (of order 106 m-3) larval/postlarval densities in floc from a coastal embayment, this study experimentally identified physical and behavioral mechanisms responsible for these associations. In annular-flume studies, sediment cores were mounted flush with the channel bottom, serving as the floc source. Larval (Capitella sp. I, a polychaete worm) distributions in the flume were consistent with predictions for transported particulates. Floc and larvae accumulated at the channel inner corner in high flows (shear velocities, u*, of 0.8 and 1.6 cm s-1), but not in low flows (u* of 0, 0.2 and 0.4 cm s-1). Inner-corner concentrations of larvae/floc resulted from a predictable, cross-channel, bottom flow in that direction. In still-water behavioral assays, there were no significant differences in percent metamorphosis among flocs fabricated from particulate-laden seawater, conspecific fecal pellets (compact floc) and organic-rich sediment. Surficial aggregates clearly were acceptable settlement substratum. This study is the first to show that settling larvae associate with surficial aggregates via both physical and behavioral mechanisms. Floc may be a transient larval venue facilitating habitat search, providing nutrition, or offering protection from predators. Alternatively, it could confer high mortality, reducing larval flux to the bed. Associations between larvae and floc do not supersede established mechanisms of habitat selection. They just thicken the plot.This study was supported by the National Science Foundation (OCE 97-29972 and OCE 02-42321), NOAA California Sea Grant College Program (R/F-197) and the UCLA Council on Research

Role of β3-adrenergic receptors in the action of a tumour lipid mobilizing factor

Induction of lipolysis in murine white adipocytes, and stimulation of adenylate cyclase in adipocyte plasma membranes, by a tumour-produced lipid mobilizing factor, was attenuated by low concentrations (10−7–10−5 M) of the specific β3-adrenoceptor antagonist SR59230A. Lipid mobilizing factor (250 nM) produced comparable increases in intracellular cyclic AMP in CHOK1 cells transfected with the human β3-adrenoceptor to that obtained with isoprenaline (1 nM). In both cases cyclic AMP production was attenuated by SR59230A confirming that the effect is mediated through a β3-adrenoceptor. A non-linear regression analysis of binding of lipid mobilizing factor to the β3-adrenoceptor showed a high affinity binding site with a Kd value 78±45 nM and a Bmax value (282±1 fmole mg protein−1) comparable with that of other β3-adrenoceptor agonists. These results suggest that lipid mobilizing factor induces lipolysis through binding to a β3-adrenoceptor

Community Voices and the Impact of Global Awareness

In this session, distinguished members of the larger Dayton community spoke about how they have promoted global engagement in the area and made suggestions on what additional steps need to take place to turn Dayton into a genuinely global city/community.https://ecommons.udayton.edu/global_voices_2/1007/thumbnail.jp