Cuticle ultrastructure of Hesionid polychaetes (Annelida)

Summary The structure of the cuticle in the four species of the family Hesionidae(Microphthalmus cf.listensis, M. cf.similis, Hesionides arenaria, juv.Podarke spec.) investigated basically corresponds to that found in all annelids. It consists of an outer, electron dense layer, epicuticle, basal cuticle with a fibrous layer, and numerous microvilli which penetrate the layers and are covered by a more or less dense glycocalyx. However, a rough collagen grid is not developed, the fibers are much thinner and are arranged in a more irregular manner. This corresponds to structures found in archiannelids and polychaete larvae. We consider them here to be reductions of the typical polychaete cuticle and postulate a correlation to the small body size of the species investigated. The quantitative differences in cuticle dimensions in the various body regions and structures can also be explained on a purely functional basis, especially apparent in the comparison of prostomium and body trunk. The pharynx cuticle shows significant structural differences due to the development of an additional peripherical lamellar layer-known to this extent only in gastrotrichs—as well as differently shaped and unusually long microvilli. This character is discussed as a possible synapomorphy for the family Hesionidae.

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Zusammenfassung Der Aufbau der Kutikula der 4 untersuchten Species aus der Familie Hesionidae(Microphthalmus cf.listensis, M. cf.similis, Hesionides arenaria, juv.Podarke spec.) entspricht grundsätzlich den Verhältnissen bei allen Anneliden: äußere elektronendichte Schicht, Epikutikula, basale Kutikula mit Faserschicht und zahlreiche Mikrovilli, die diese Schichten durchbrechen und von einem mehr oder weniger dichten Glykokalyx bedeckt sind. Ein derbes Kollagengitter ist jedoch nicht ausgebildet; die Fibrillen der Faserschicht sind wesentlich feiner und unregelmäßiger angeordnet. Dies entspricht Strukturen, wie sie bei Archianneliden und bei Polychaetenlarven gefunden werden. Wir deuten sie hier als Reduktionen der typischen Poly chaetenkutikula und vermuten eine Beziehung zur geringen Körpergröße der untersuchten Arten. Rein funktionell lassen sich auch die quantitativen Unterschiede in den verschiedenen Bereichen der Körperoberfläche deuten, die besonders im Vergleich von Prostomium und Rumpf zum Ausdruck kommen. Die Pharynxkutikula zeigt starke strukturelle Abweichungen durch die Ausbildung einer zusätzlichen peripheren Lamellenschicht (in diesem Ausmaß nur von den Gastrotrichen bekannt) und abweichend geformter, besonders langer Mikrovilli. Dieses Merkmal wird als mögliche Synapomorphie für die Familie Hesionidae diskutiert.

     

Klinefelter's syndrome and incontinentia pigmenti Bloch-Sulzberger

Summary We report a newborn with incontinentia pigmenti Bloch-Sulzberger and male phenotype. Chromosome analysis revealed a Klinefelter's syndrome 47,XXY. These findings are compatible with the hypothesis of dominant sexlinked genes carried on the X-chromosome in this disease.

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Zusammenfassung Wir berichten über ein neugeborenes Kind mit männlichem Phänotyp bei Incontinentia pigmenti Bloch-Sulzberger. Bei der klinischen Abklärung fand sich die Gonosomenaberration eines Klinefelter-Syndroms 47,XXY. Dieser Befund geht konform mit der Vermutung eines dominant X-gekoppelten Erbganges dieser seltenen Hauterkrankung.

     

Relation between brain 5-HIAA levels and the release of serotonin into brain synapses

Our findings in experiments using reserpine, an amine releaser, and fluoxetine, a serotonin uptake blocker, indicate that the reuptake of serotonin from brain synapses precedes its transformation to 5-hydroxyindoleacetic acid (5-HIAA). Male rats were injected with reserpine or fluoxetine alone, or with fluoxetine one hour before reserpine; control animals received diluents. Reserpine lowered brain serotonin and raised brain 5-HIAA levels. Fluoxetine alone did not change serotonin levels but lowered 5-HIAA. Fluoxetine completely antagonized the reserpine-induced increase in 5-HIAA, and significantly enhanced its depletion of serotonin. In order to determine whether the ability of fluoxetine to block the rise in 5-HIAA after reserpine resulted from its effect on serotonin reuptake or from suppression of impulse flow along serotoninergic neurons, we also examined the effects of the drugs on serotonin metabolism in distal portions of acutely transected neurons (which, presumably, were no longer able to conduct impulses). No differences were noted between the responses of intact and lesioned serotoninergic neurons, indicating that fluoxetine's blockade of the rise in brain 5-HIAA results from its effect on serotonin reuptake.     

Different legumin protein domains act as vacuolar targeting signals.

Legumin subunits are synthesized as precursor polypeptides and are transported into protein storage vacuoles in field bean cotyledons. We expressed a legumin subunit in yeast and found that in these cells it is also transported into the vacuoles. To elucidate vacuolar targeting information, we constructed gene fusions of different legumin propolypeptide segments with either yeast invertase or chloramphenicol acetyltransferase as reporters for analysis in yeast or plant cells, respectively. In yeast, increasing the length of the amino-terminal segment increased the portion of invertase directed to the vacuole. Only the complete legumin alpha chain (281 amino acids) directed over 90% to the vacuole. A short carboxy-terminal legumin segment (76 amino acids) fused to the carboxy terminus of invertase also efficiently targeted this fusion product to yeast vacuoles. With amino-terminal legumin-chloramphenicol acetyltransferase fusions expressed in tobacco seeds, efficient vacuolar targeting was obtained only with the complete alpha chain. We conclude that legumin contains multiple targeting information, probably formed by higher structures of relatively long peptide sequences.