The occurrence of polysialogangliosides including ganglio-N-tetraose series in adult bovine nasal cartilage

We extracted glycolipids from adult bovine nasal cartilage and purified some glycolipids by DEAE-Sephadex A-25 and Iatrobeads column chromatography. Cartilage contained 20 nmol of lipid bound sialic acid per gram wet tissue. The relative content of mono, di, tri, and tetrasialo gangliosides were 14%, 40%, 28% and 18%, respectively, as sialic acid content. We characterized some by examining carbohydrate composition, methylation analysis, sialidase treatment and mild acid hydrolysis. The ganglio-N-tetraose series, including GDla, GDlb, GTla, GTlb and GQlb, was identified as one of the major ganglioside groups of this cartilage.     

Die spektrale Transmission des dioptrischen Apparates von Aeschna cyanea Müll.

Zusammenfassung Die spektrale Transmission wurde mit dem UMSP (UniversalMicro-Spektralphotometer) im Bereich von 550–300 nm am fixierten (Carnoy) und frischen dioptrischen Apparat einzelner Ommatidien von Aeschna cyanea Müll. (Odonata) gemessen.Die Transmission der Kristallkegel und der frischen Cornea ist zwischen 550–370 nm nahezu konstant; bei kürzeren Wellenlängen des UV-Bereiches sinkt die Transmission etwas. Erst bei Wellenlängen, die kürzer als 330 nm sind, wird der Transmissionsabfall signifikant.

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The spectral transmission of the dioptric apparatus of aeschna

Summary Spectral transmission was measured by means of a Zeiss Universalmicro-spectralphotometer between 550 and 300 nm on fixed (Carnoy) and also on fresh cornea and crystalline cones of single ommatidia of Aeschna cyanea Müll. (Odonata).Both crystalline cones and fresh corneas (in contrast to fixed corneas) have nearly constant transmission from 550 to 370 nm; in uv-range with shorter wavelengths the transmission decreases slightly. Only at wavelengths shorter than 330 nm is the absorption significant.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.

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Mit Unterstützung der Alexander von Humboldt-Stiftung.     

Spike Potentials Recorded from the Insect Photoreceptor

Slow and spike potentials were recorded from single cells in the receptor layer of the compound eye of the drone of the honeybee. From electron microscopic observation of the drone ommatidium, it was concluded that the response had been recorded from the retinula cell. The following hypothesis is suggested for the initiation of spike potentials in the drone compound eye: Photic stimulation results in a decrease in the resistance of all or part of the retinula cell membrane, giving rise to the retinal action potential. The retinal action potential causes outflow of the current through the proximal process of the cell. This depolarizing current initiates spike potentials in the proximal process or axon of the retinula cell which are recorded across the soma membrane of the retinula cell.     

The Development of the Rhabdom and the Appearance of the Electrical Response in the Insect Eye

Electron microscopic studies on the development of the rhabdom in the compound eye of the silkworm moth and pupa (Bombyx mori) were carried out in parallel with the recording of the electrical response to photic stimulation. No electrical response to photic stimulation was recorded from the pupal compound eye which had no trace of differentiation of the rhabdom. With the differentiation of development of the rhabdom in the pupal compound eye, electrical responses could be recorded, and the amplitude of such electrical responses increased with the progress of development of the rhabdom. These observations suggest that the rhabdom is probably the site of the photochemical reaction which leads to the generation of the slow retinal action potentials.     

Cellular basis for polarized light perception in the spider crab,Libinia

Summary Differential increases in the numbers of pinocytotic vesicles, multivesicular bodies and total complex bodies occurred in the cytoplasm of specific photoreceptor cells in the compound eye of the crab Libinia exposed for six hours to polarized light with various e-vector orientations. These data coupled with previous results on the same species proved that the seven retinular cells in each ommatidium formed two functional groups selectively light adaptable by e-vectors oriented 90° apart. One group (Channel I, comprising Cells 1, 4 and 5) was more affected by horizontal polarization; the other (Channel II, comprising Cells 2, 3, 6 and 7) was more affected by vertical polarization.This confirmed by a quite independent technique the conclusion reached from electrophysiological experiments on the crab Cardisoma that decapod compound eyes have two orthogonal polarization analyzer channels. In addition the present data showed that both channels occur in each ommatidium as hypothesized on previous electron microscopic evidence and that the axes of maximum absoprtion in the two retinal channels were parallel to the long axes of their cells' rhabdom microvilli, horizontal in Channel I and vertical in Channel II. The latter relations in turn supported the hypothesis that the dichroism of rhodopsin was fundamental to the analyzer mechanism.This research has been supported by U. S. Air Force Grant AFOSR 1064 and NASA Grant NGR 07-004-055. The authors wish to thank Professor Joseph G. Gall for generously sharing his electron microscope facilities.     

Changes in retinal fine structure induced in the crab Libinia by light and dark adaptation

Summary The cytological influence of light and dark adaptation (LA and DA) on the retinular cells of the spider crab Libinia emarginata has been studied by light and electron microscopy in four adaptive states: 17 hours darkness, 5 hours darkness, 5 hours diffuse light and 17 hours diffuse light. The rhabdom's fine structure is typical of decapods but its dual overall form and position mingle certain features of both apposition and superposition compound eye types. Distal and proximal retinal pigments both showed adaptive migration, but the distal pigment cells moved over a restricted range, and DA separated the retinular cell pigment granules into two groups, perinuclear and basilar.In the rhabdom no changes in its position, dimensions or microvillus fine structure were observed with LA or DA. But at the base of the rhabdom microvilli the rate of pinocytosis was strongly affected by the eye's adaptive state, being lowest after 17 hours DA and greatest after 17 hours LA; the wall of the 0.1 microvesicles so formed, looked like the membrane of the rhabdom microvillus and they were the same size as the vesicles in multivesicular bodies and in vesicular lamellar bodies.Three categories of complex cytoplasmic particles about 1 in diameter (multivesicular bodies, vesicular lamellar bodies and purely lamellar bodies) were all increased in number by decreased DA and by increased LA; similar quantitative effects occurred in the endoplasmic reticulum and in the ribosomes.The pinocytotic vesicles and the complex cytoplasmic bodies may represent part of an intracellular system to dispose of rhabdom metabolites whose production was initiated or increased by light absorption.Cytoplasmic and perirhabdomal vacuoles mainly distal in location, were also affected by light, but inversely; their maximal extent occurred after 17 hours DA; less DA or any LA significantly decreased their presence and aggregation.The data reported are of interest not only because they correlate retinal fine structure with the metabolism of vision but also because they provide a new and specific tool for distinguishing active from inactive neurosensory cells in the optic pathway.This research was initiated with the aid of U.S. Public Health Service Grant NB-03076 and has been continued with the support of U.S. Air Force Grant AFOSR-1064. The authors wish to thank Dr. Joseph G. Gall and Dr. William R. Adams for generously sharing their electron microscopic facilities; they are also grateful to Mrs. Mabelita Campbell for her collaboration on the light microscopy.     

Synthesis and biological activity of (22E,25R)- and (22,25S)-22-dehydro- 1 alpha,25-dihydroxy-26-methylvitamin D3

Both 25-epimers of (22E)-22-dehydro-1 alpha,25-dihydroxy-26-methylvitamin D3 [22-dehydro-26-methyl-1,25-(OH)2D3] were synthesized. The biological activity of these compounds was tested in binding affinity to chick intestinal receptor protein of 1 alpha,25-dihydroxy-vitamin D3 [1,25-(OH)2D3] and in stimulating for intestinal calcium transport and bone calcium mobilization with vitamin D-deficient rats. The relative potency of (25R)- and (25S)-22-dehydro-26-homo-1,25-(OH)2D3 and 1,25-(OH)2D3 in competing for the intestinal cytosolic binding was 1.7:1.5:1. A similar order of activity was observed on intestinal calcium transport and bone calcium mobilization. In the ability for stimulation of intestinal calcium transport, (25R)- and (25S)-22-dehydro-26-methyl-1,25-(OH)2D3 were about 3.6 and 2.1 times as active as 1,25-(OH)2D3, respectively. In bone calcium mobilization tests, (25R)- and (25S)-22-dehydro-26-methyl-1,25-(OH)2D3 were estimated to be 2.2 and 1.6 times as potent as 1,25-(OH)2D3, respectively.     

Ontogenesis of α2-Adrenoceptor Coupling with GTP-Binding Proteins in the Rat Telencephalon

The ontogenesis of alpha 2-adrenoceptors and GTP-binding proteins and their coupling activity were investigated in telencephalon membranes of developing rats. The manganese-induced elevation of [3H]clonidine binding was increased in an age-dependent manner but the guanosine 5'-O-(3-thio)triphosphate-induced decrease in binding did not change. The extent of the binding of [3H]clonidine at 15 nM (saturable concentration) increased in an age-dependent manner and reached the adult level at 4 days after birth. Cholera toxin and pertussis toxin catalyzed ADP-ribosylation of proteins of 46 and 41/39 kilodaltons (kDa) in solubilized cholate extracts of the membranes. The 41/39-kDa proteins ADP-ribosylated by pertussis toxin (Gi alpha + Go alpha) were increased with age and reached the adult level at day 12, whereas the 46-kDa protein (Gs alpha) reached its peak on day 12 and then decreased to the fetal level at the adult stage. The immunoblot experiments of the homogenates with antiserum (specific antibody against alpha- and beta-subunit of GTP-binding proteins) demonstrated that the 39-kDa alpha-subunit of (Go alpha) and the 36-kDa beta-subunit of GTP-binding protein (beta 36) increased with postnatal age. In contrast, 35-kDa beta-subunit (beta 35) did not change. From these results, it is suggested that the coupling activity of alpha 2-adrenoceptor with GTP-binding protein gradually develops in a manner parallel with the increase of alpha 2-adrenoceptor and pertussis toxin sensitive GTP-binding proteins, Gi, and that alpha 39 beta 36 gamma may be related to the differentiation and/or growth of nerve cells in rat telencephalon.