Herring bodies; an electron microscopic study of local degeneration and regeneration of neurosecretory axons

Summary The Herring bodies in the posterior lobe of the bovine hypophysis are very large (2–600 ) and can be classified into three types. The type I Herring body contains an accumulation of neurosecretory granules. These Herring bodies are very scarce and should not be confused with the numerous, but small, axonal swellings which also contain neurosecretory granules.The type II Herring body is characterized by the presence of a varying number of normal, moderately electron dense and empty vesicles, autophagic vacuoles, multilamellate bodies and occasional mitochondria. These Herring bodies are frequently observed.The type III Herring body is typified by the presence of dense vesicles connected to tubular formations which contain material of variable electron density, of filaments, and of long slender and very numerous mitochondria.The presence of multilamellate bodies and autophagic vacuoles suggests that the type II Herring body is in a degenerating phase. This concept is further substantiated by the similarity between this type of Herring body and transected neurosecretory axons in which degeneration is occurring.A similar comparison suggests that the type III Herring body is undergoing a regenerative process. Our current concept of the structure and function of Herring bodies is revised in the discussion.This work was supported by grants 5 RO1 NB 06641 NEUA and 5 R0107492 NEUA from the National Institutes of Health and the Space Sciences Research Center of the University of Missouri. The technical assistance of Mrs. G. Clark and Mr. R. Faup, and the clerical assistance of Mrs. S. Schmidt are gratefully acknowledged.Fellow of the Conséjo National de Investigaciones Científicas y Tecnicas de la República Argentína.     

Light and electronmicroscope study of one of the systems of centrifugal fibers found in the lamina of muscoid flies

Summary By combining the Golgi and the electronmicroscope techniques it has been possible to identify accurately the system of centrifugal fibers which arborizes in the lamina of muscoid flies forming the so-called nervous bags. Each of them originates from a single fiber entering the lamina at the site in which the second order and the long visual fibers leave it. This single fiber represents the peripheral portion of a T-shaped trunk stemming from a small neuronal body located in the external region of the medulla. The central branch terminates within the first synaptic field of this visual center.After entering the lamina the centrifugal fiber ramifies profusely and its branches can be seen climbing and synapsing on the surface of the photoreceptor axon endings. The synaptic loci show characteristic synaptic ribbons located within the nervous bag fibers. This fact suggests that direction of conduction is from the medulla to the lamina. This study has also revealed that the intramedullar terminals of the centrifugal fibers establish intimate contacts with one of the two second order fiber endings.This work was supported by Grant No. 618–67 (Mod No. 67–0618) of the Office of Aerospace Research, United States Air Force and by NIH grant NSO 866901.     

Neue oder wenig bekannte Flechten in der Tschechoslowakei. I

Es werden 28 Arten von lichenisierten Fungi (Flechten) mit kritischen taxonomischen Hinweisen oder Ergänzungen zu den in der Literatur vorhandenen Beschreibungen, oft mit chorologischen Bemerkungen und Angaben über die ökologischen Verhältnisse ihrer Standorte angeführt, von denen die nachgenannten Arten und Namenskombinationen neu sind:Verrucaria scabra Vězda sp. n.,Geisleria xylophila Vězda sp. n.,Toninia steineri Poelt etVězda sp. n.,Pachyascus byssaceus (Vězda) Vězda comb. n. undMicarea gomphillacea (Nyl.) Vězda comb. n.