Lunar synchronization of the monthly reproductive rhythm in the sea urchin Centrostephanus coronatus Verrill

The monthly reproductive rhythm in the diadematid sea urchin Centrostephanus coronatus Verrill at Santa Catalina Island, California, was studied in the summer of 1973 and the results are compared with data for the summer of 1969. In the summer of 1973 the more extreme spring tides coincided with the new moon, while in the summer of 1969 the more extreme spring tides coincided with the full moon. The reproductive rhythm in both years was closely synchronized with lunar phases and not with the monthly tidal cycles; spawning occurred near the third lunar quarter in both years. These observations suggest that this monthly reproductive rhythm is synchronized by monthly changes in moonlight, and not by monthly tidal changes.     

On the structural and functional components of coated vesicles.

Despite the diversity of their known functions, coated vesicles from different tissues contain a rather similar spectrum of proteins, in addition to their major coat protein, clathrin. In particular, each coated vesicle preparation shows a doublet of polypeptide species, on sodium dodecyl sulphate-containing gel electrophoresis, of apparent molecular weight in the region 30,000 to 36,000. Using bullock brain as a source, these molecules are found in association with possible trimers or higher multiples of clathrin, obtained by dissolving coated vesicles in cholate. They may play a structural role relating to the vertices or edges of the lattices of pentagons and hexagons of the polyhedral coats.Purified coated vesicles (e.g. from chicken oocytes) seem to contain relatively small amounts of specific proteins in terms of “contents”. This suggests that the bulk of the isolated particles, especially those in the small size range (500 to 800 Å diam.), may be “empty” of contents, although many still retain a lipid vesicle. These empty structures could represent a pool of recycling coated vesicle components formed after release (possibly from larger vesicles (800 to 1500 Å diam.)) of the specific contents, at their particular destination.     

Cytochemical identification of human and murine pituitary corticotrophs and somatotrophs as APUD cells

Summary Cytochemical techniques, performed sequentially on single sections, have confirmed the identity of human and murine pituitary corticotrophs as APUD cells. These same methods indicate that in both species the acidophil somatotroph, identified as such by immunofluorescence using anti-human GH, possesses APUD qualities not only with respect to amine-handling, but also in terms of enzyme content.Inclusion of the somatotroph in the APUD series of cells which produce polypeptide hormones has far-reaching implications.     

The structural basis of airways hyperresponsiveness in asthma.

We hypothesized that structural airway remodeling contributes to airways hyperresponsiveness (AHR) in asthma. Small, medium, and large airways were analyzed by computed tomography in 21 asthmatic volunteers under baseline conditions (FEV1 = 64% predicted) and after maximum response to albuterol (FEV1 = 76% predicted). The difference in pulmonary function between baseline and albuterol was an estimate of AHR to the baseline smooth muscle tone (BSMT). BSMT caused an increase in residual volume (RV) that was threefold greater than the decrease in forced vital capacity (FVC) because of a simultaneous increase in total lung capacity (TLC). The decrease in FVC with BSMT was the major determinant of the baseline FEV1 (P < 0.0001). The increase in RV correlated inversely with the relaxed luminal diameter of the medium airways (P = 0.009) and directly with the wall thickness of the large airways (P = 0.001). The effect of BSMT on functional residual capacity (FRC) controlled the change in TLC relative to the change in RV. When the FRC increased with RV, TLC increased and FVC was preserved. When the relaxed large airways were critically narrowed, FRC and TLC did not increase and FVC fell. With critical large airways narrowing, the FRC was already elevated from dynamic hyperinflation before BSMT and did not increase further with BSMT. FEV1/FVC in the absence of BSMT correlated directly with large airway luminal diameter and inversely with the fall in FVC with BSMT. These findings suggest that dynamic hyperinflation caused by narrowing of large airways is a major determinant of AHR in asthma.     

Cotranslocational degradation: utilitarianism in the ER stress response

Recently, a new layer of the unfolded protein response was discovered that supports the cotranslocational degradation of nascent chains stalled in endoplasmic reticulum translocons (Oyadomari et al., 2006).