Alterations of Inositol Lipid Metabolism of Rat Sciatic Nerve in Streptozotocin-Induced Diabetes

Abstract: The composition and metabolism of rat sciatic nerve phospholipids were studied 20 weeks after induction of chronic diabetes by intraperitoneal injection of streptozotocin (50 mg/kg). On a wet weight basis the nerves from the diabetic animals showed a 7% decrease in total phospholipid from that of controls and a relative decrease in phosphatidylinositol. Incubations of isolated sciatic nerves of diabetic rats in a medium containing [³³P]orthophosphate gave decreased labeling of phosphatidylinositol and substantial changes in the labeling pattern of phosphatidylinositol phosphate and 4,5-bisphosphate from that of controls. The ratio of label in these polyphosphoinositides decreased from 2.5 for normal nerve to about 1.0 for diabetic nerve within a 2-h incubation period. These metabolic alterations were not observed in acutely diabetic animals 5 days after streptozotocin (100 mg/kg) administration. Because polyphosphoinositides may be involved in the control of membrane permeability during axonal conduction, alterations in their relative amounts or turnover rates could be related to the physiological changes of early diabetic neuropathy.     

The effect of nisin on murein synthesis

Nisin inhibits murein synthesis with concomitant accumulation of undecaprenyl-pyrophospho-MurNAc(pentapeptide) (lipid intermediate I). This inhibition is caused by the formation of a complex between the antibiotic and lipid intermediate I. Undecaprenyl-pyrophospho-MurNAc(pentapeptide)-GlcNAc (lipid intermediate II) also forms a complex with nisin. However, when murein synthesis is inhibited by nisin, this latter complex is not formed since lipid intermediate II is no longer synthesized.Abbreviations GlcNAc N-acetylglucosamine - MurNAc N-acetylmuramyl - Pentapeptide Ala--DGlu-Lys-DAla-DAla - C₅₅ undecaprenol Dedicated to Professor Otto Kandler on occasion of his 60th birthday     

Hereditary motor endplate disease (med) of the mouse: Observations on dissociated myogenic cells and their development in culture

Summary Myogenic cells from mice homozygous for the lethal mutation motor endplate disease (med/med) were grown in culture. Like muscle cells taken from wild type (+/?) litter mates they fused to form myotubes which contracted, developed cross striations, and exposed acetylcholine receptors (AChR) on their surface. However, a decrease of 30% in the number of mononucleated cells per unit fresh weight of muscle was observed as early as 2–3 days postnatal, i.e., at least one week prior to the onset of physiological symptoms. Hence, in addition to influencing the functional maintenance of motor endplates, the med gene seems to control early events in muscle development.     

Isolation and characterization of noradrenalin storage granules of bovine adrenal medulla

A method is described for the preparation of (1) the heavy population of bovine adrenal chromaffin granules ($\text{S}{}_{\mathrm{<mtext>H</mtext>}}\text{(}\text{average sedimentation coefficient}\text{) = 12 400}\text{S}$ in 0.25 M sucrose) essentially free from contamination with mitochondria and other organelles, and (2) a subpopulation of this heavy population which is highly enriched in noradrenalin ($\text{?95\%}$ of the total catecholamine is noradrenalin). The method is based on isopycnic gradient centrifugation using a self-generating gradient of polyvinylpyrrolidone-coated colloidal silica particles (Percoll) in 0.5 M sucrose medium.The isolated population of noradrenalin granules appeared highly electron dense in transmission electron microscopy and revealed a rather narrow size distribution. The specific content of amine and adenine nucleotides (with reference to total granule protein) was markedly higher than for the total population of heavy chromaffin granules. The molar ratio of amines to adenine nucleotides was, however, lower in the noradrenalin granules, i.e. 4.8 vs. 11.9.     

Ultrastructure of the heart of the sturgeon Acipenser stellatus (Chondrostei)

Summary The ultrastructure of atrial and ventricular myocardial cells from Acipenser stellatus is described. The cells of the atrium are more loosely connected than those of the ventricle. Cell contact is by simple intercalated discs and by desmosomes. The cells are flattened, with peripheral myofibrils and a central region of mitochondria and the nucleus. The sarcoplasmic reticulum consists of subsarcolemmal tubules, that frequently extend towards the central mitochondria. Dyads are small and positioned at any sarcomeric level. No T-tubules are present. Specific granules are restricted to the atrial cell, and are sometimes present within the SR tubules.     

Estimation of signal and noise spectra by special averaging techniques with application to a posteriori “Wiener” filtering

This paper deals with the problem of separating the spectra of signal and noise in ensembles where the signal can be considered as an invariant component and the noise as a stationary additive background. Several methods are discussed and compared on the basis of a statistical analysis of the first two moments of the estimators for signal and noise spectra. As a consequence a procedure is proposed which provides a flexible compromise between estimation accuracy and computational effort. The application of this procedure to a posteriori Wiener filtering is compared with a more common, but time consuming, technique.     

Präadaption bei Flechten iranischer Halbwüsten

25 species of lichens have been collected in semidesertic to desertic areas of Iran. On the basis of spatial relations to the substrate and anatomical features of the thallus three main groups (one with a subdivision based on colour and morphology of the thallus) can be differentiated. Selective advantages and peculiarities in connection with the desert habitat are pointed out, such as inverse thallus-structure, a dense network of skeletal hyphae in the substrate in otherwise epilithic species, proliferating areolae of the thallus, immersed pycnidia with trichogynes and brownish spores in groups with usually colourless spores. Most of the species are wide-spread in arid and often also in humid regions; only one species,Verrucaria buschirensis J. Steiner, seems to be endemic. The prevalence of cyanophilic lichens in deserts may have phylogenetic reasons, as these groups appear to date back to periods without higher vegetation and a desert-like environment.

Herrn Prof. Dr. L.Geitler zum 80. Geburtstag gewidmet.     

Feinstruktur der Tarsal-Drüse vonSiro duricovius (Joseph) (Opiliones,Sironidae)

Zusammenfassung Alle Arten der Sironidae tragen als sekundäres männliches Geschlechtsmerkmal ein epidermales Drüsenorgan im letzten Tarsalglied des 4. Laufbeines. Das Sekret tritt dort dorsal, exponiert auf einer kanülenartigen Apophyse, dem Adenostyl, nach außen.BeiSiro duricorius (Joseph, 1868) besteht das komplexe Drüsenorgan aus zahlreichen funktionellen Einheiten, deren Sekret einem gemeinsamen Kanal zugeführt wird; er öffnet sich auf dem Adenostyl. Jede funktionelle Drüseneinheit umfaßt 5 Zellen: 3 Drüsenzellen (DZ, Dreiergruppe), 1 Hüllzelle (HZ), 1 Kanalzelle (KZ). Die Sekrete werden in ein gemeinsames Reservoir abgegeben.HZ verknüpft manschettenartig die DZ mit der KZ. Eine Randeinfaltung am Apex der DZ gewährleistet innige Verfalzung von diesen mit der HZ.DZ und HZ sind mit gut entwickeltem Mikrovillisaum ausgestattet; beide Zelltypen sezernieren.Der ableitende Kanal der GZ besteht aus 2 Abschnitten: ein distaler schwammig-fibrillärer und ein proximaler massiver; beide Teile werden von nur einer Zelle (KZ) begleitet. Der basale Teil mündet in den Hauptkanal, der zum Adenostyl zieht.Neben diesem komplexen Drüsenorgan liegt ein ähnlich gebautes, aber kleineres ventral im Tarsus; sein Sammelkanal zieht zum Kanal der Hauptdrüse.Isolierte funktionelle Einheiten sind in der Tarsenepidermis weit verstreut; sie leiten ihr Sekret unmittelbar auf die Tarsusoberfläche.Die DZ produzieren nach elektronenoptischer Evidenz ein Protein. Das Sekret der HZ läßt sich bisher nicht zuordnen; es ist von dem der DZ verschieden.

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Ultrastructure of the tarsal gland ofSiro duricorius (Joseph)

Summary All species of Sironidae possess as a secondary male sex character an epidermal gland organ in the last tarsal joint of the fourth leg. The glandular secretion emanates from a conical apophysis, the adenostyl, which is located dorsally on the joint.InSiro duricorius (Joseph, 1868) the complex organ consists of numerous functional units, the secretion of which flows into the common channel opening on the adenostyl.Every gland unit contains 5 cells: 3 gland cells (DZ), 1 enveloping cell (HZ), 1 duct cell (KZ). The enveloping cell connects the gland cells with the duct cell like a sleeve. A marginal fold of the gland cell apex provides tight connection of gland cells and enveloping cell.Gland cells and enveloping cell are equipped with microvilli, and both cell types secrete in a common reservoir.The duct of the duct cell is divided into two parts: 1) a distal fibrillaceous-spongy one and 2) a proximal massive one. Both are accompanied only by a single duct cell.Besides this complex gland organ a similar one is located in the ventral part of the tarsus. Its collecting channel opens into the channel of the main gland.Isolated functional gland units are scattered over the epidermis of the tarsus; their secretion flows immediately on the tarsal surface.The gland cells proper produce a protein, the fact is indicated by the electronmicrographs. The secretion of the enveloping cell is a different one, but at this time cannot be attached to a chemical group.

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Abkürzungen A Adenostyl - aSe austretendes Sekret - C Kutikulin - Cu Kutikula - dK distaler Kanal - DK Kern der Drüsenzelle - DZ Drüsenzelle - ER rauhes endoplasmatischesm, Retikulum - G Golgi-Apparat - HK Kern der Hüllzelle - HZ Hüllzelle - K Kralle des Tarsus - Ke Kern - KK Kern der Kanalzelle - KZ Kanalzelle - M Mikrovilli - Mi Mitochondrium - pK proximaler Kanal - R Randeinfaltung der DZ - Re extrazelluläres Reservoir - Ri Ribosomen - Se Sekret - SK zentraler Sammelkanal - T Mikrotubuli - Va Vakuole - Va₁-Va₆ Vakuolen mit Sekret unterschiedlichen Reifegrades     

Fine structure of anaphase bridges in meiotic chromosomes of the crane fly Pales

Chromatin bridges of autosomal bivalents in anaphase I were observed in spermatocytes of Pales ferruginea. The bridges are formed without simultaneous production of akinetochoric (akinetic) fragments. A bridge consists of a single fiber up to approximately. 500 Å in diameter. Filamentous substructures of approximately 100 Å diameter can be visualized. It is suggested that these bridges represent a low order coiling of the chromatid, and may be caused by non-separation of the terminal segments of the chromatids (telomeres).     

Auxin in scapes,flower buds,flowers, and fruits of daffodil (Narcissus pseudonarcissus L.)

Summary Diffusates from flower buds, flower fruits, and scape segments, and extracts of flower stalks of Narcissus pseudonarcissus contain an auxin active in the Avena geo-curvature test. The auxin behaved like indole-3-acetic acid (IAA) in thin-layer chromatography (TLC) with neutral and basic solvents on different adsorbents. After TLC, the auxin of the extracts showed chromogenic reactions identical with those of IAA; in gas-liquid chromatography on two different columns, the purified substance, after methylation, appeared at the retention time of IAA methyl ester. The auxin content of the extracts has been estimated to be equivalent to ca. 10 g IAA kg^–1 fresh weight. Diffusates, collected at the basal end of excised flowering apices and of scape segments at different developmental stages, showed highest auxin activity when collected from old buds and young flowers, and from the basal, rapidly elongating scape regions. The diffusible auxin obtained from scape segments was very likely produced by the segments themselves. Thus, the shoot of Narcissus appears to possess two different sites of auxin production, namely, the apical region represented by the flower bud, the flower or the fruit, and the scape.Abbreviations IAA indole-3-acetic acid - IAA-OMe indole-3-acetic-acid methyl ester - TLC thin-layer chromatography - GLC gas-liquid chromatography