Differential effects of aldosterone and ADH on intracellular electrolytes in the toad urinary bladder epithelium

Summary Quantitative electron microprobe analysis was employed to compare the effects of aldosterone and ADH on the intracellular electrolyte concentrations in the toad urinary bladder epithelium. The measurements were performed on thin freeze-dried cryosections utilizing energy dispersive x-ray microanalysis. After aldosterone, a statistically significant increase in the intracellular Na concentration was detectable in 8 out of 9 experiments. The mean Na concentration of granular cells increased from 8.9±1.3 to 13.2±2.2 mmol/kg wet wt. A significantly larger Na increase was observed after an equivalent stimulation of transepithelial Na transport by ADH. On average, the Na concentration in granular cells increased from 12.0±2.3 to 31.4±9.3 mmol/kg wet wt (5 experiments). We conclude from these results that aldosterone, in addition to its stimulatory effect on the apical Na influx, also exerts a stimulatory effect on the Na pump. Based on a significant reduction in the Cl concentration of granular cells, we discuss the possibility that the stimulation of the pump is mediated by an aldosterone-induced alkalinization.Similar though less pronounced concentration changes were observed in basal cells, suggesting that this cell type also participates in transepithelial Na transport. Measurements in mitochondria-rich cells provided no consistent results.     

Experimental reovirus myocarditis in newborn mice. Electron microscopic observations

Reovirus is a double-stranded RNA-virus which induces myocarditis in newborn mice. Due to the large diameter of the viral particles (70-75 nm) it can be detected by electron microscopy. Subcutaneous inoculation of 0.05 ml reovirus type 3 (TCID50-titer: 10(8.5)/ml) into newborn NMRI-mice (12-18 h after birth) caused a grey-yellow mottling on the ventricular surface first seen on the 5th day after birth. At the same time muscle fiber necrosis was observed which increased with time. Electron microscopic investigations of the diseased heart muscle disclosed a marked interstitial oedema, swelling of the tubular system and sarcoplasmic reticulum, and degenerative changes in the mitochondria of individual myocardiocytes as early as the 2nd post-inoculation day. Simultaneously, an enlarged Golgi-apparatus and an increasing number of lysosomes, partially exhibiting acid phosphatase activity, was detected in the perinuclear region of ventricular myocardiocytes. On the 5th day after infection, viruses were detected either within single membrane vesicles, dispersed in cytoplasm or as aggregated clusters in the perinuclear region. These in vivo electron microscopic findings correspond with observations of virus propagation in cell-culture systems.     

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.     

Amino acid pool and protein turnover during differentiation (spherulation) ofPhysarum polycephalum

The composition of the amino acid pool during spherulation was determined. It changes in size and in composition, the concentration of each amino acid behaving individually. The first response to the onset of spherulation either by starvation or osmotic shock (0.5 M mannitol) always is a decrease of the pool's size, which during further starvation expands for a short period and then decreases again. During development induces by mannitol in the presence of external amino acids, the pool size increases continuously after the initial depletion.As shown by radioactive labeling, amino acids were actively released from the plasmodium into a medium containing amino acids, but retained by the microplasmodia in an amino acid-free medium. The kinetics of the uptake of radioactive amino acids from the medium is biphasic, indicating the existence of multiple pools. Even after a labeling period of 8 h the amino acid pool is not yet in equilibrium with the medium. The possibility of a compartimentation of the pool was confirmed by density labeling of two different enzymes.Whereas the turnover of total protein is only very low during growth, it is rather high in spherulating microplasmodia. At least 70% of the originally existing protein is degraded during this development, while, simultaneously, at least 50% of the protein present after 24 h starvation is newly synthesized during that period.     

Effect of ultraviolet radiation on the microsporidian Octosporea muscaedomesticae with reference to protectants provided by the host Phormia regina

The effect of ultraviolet light on the microsporidian Octosporea muscaedomesticae in relation to infection in the adult black blowfly, Phormia regina, was investigated. A 30-Watt germicidal lamp, 253.7-nm wavelength, was used as source of uv light in five investigations. In addition, sunlight served as a uv source in two studies. Viable naked dried spores exposed to the uv lamp at a distance of 10 cm were killed after 15 min. Viable naked spores in an aqueous suspension were killed after 30 min of exposure to the uv lamp and after 3 hr of exposure to bright sunlight, respectively. Daily 30-min uv lamp exposures on living hosts harboring all life phases of the parasite did not interfere with the ensuing infection in the blowfly's midgut and the pathogen's developmental cycle. Spores harvested from uv-treated infected hosts were found to be as infective as spores retrieved from hosts not treated with uv. Spores contained in dried fecal droplets and exposed up to 3 hr to the uv lamp, or 12 hr to bright sunlight, respectively, remained infective. Addition of uric acid to a preparation of naked spores prior to 15- and 30-min uv irradiations yielded 100% infection in both host groups. A uv-protective function is ascribed to components provided by the host's tissues and feces.     

Ergänzende Untersuchungen zur Ultrastruktur von Trichoplax adhaerens F.E. Schulze (Placozoa)

Zusammenfassung 1. Die Zellen des Ventralepithels bilden keine Mikrovilli, sondern ein schwammartiges Maschenwerk gefensterter Leisten und Falten, welches bei der Haftung des Tieres an der Unterlage und/oder bei der extrasomatischen Vorverdauung der Nahrung eine Rolle spielen dürfte.2. Während der Zellteilungen treten typische Centriole an den Spindelpolen auf.3. Die wachsenden Eizellen phagocytieren Fortsätze der Faserzellen, die als Trophocyten fungieren.4. Unter den gleichen Bedingungen, die zur Eibildung führen, können sogen. S-Zellen auftreten. Einige ultrastrukturelle Befunde sprechen dafür, daß es sich um Spermien handelt.

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Additional investigations on the ultrastructure of Trichoplax adhaerens F.E. Schulze (Placozoa)

Summary 1. The cells of the ventral epithelium form no microvilli but a spongy meshwork of fenestrated ledges and folds which may play a rôle in the adhesion of the animal to the substratum and/or in the extrasomatic predigestion of the food. 2. During cell division typical centrioles occur at the spindle poles. 3. The growing egg cells phagocytize projections of the fiber cells which function as trophocytes. 4. Under the same conditions leading to egg formation so-called S-cells may occur. Some ultrastructural data suggest that they are sperm cells.

     

Cocultivation studies with cells of patients bearing fragile X chromosomes

Summary Fourteen cocultivation studies were carried out with cells of four patients with fragile X, one obligate and two possible female heterozygotes, two female controls, and a rabbit. In all cocultivations the number of fragile X chromosomes was sharply reduced in the patient cells. The strongest effect was caused by the animal cells. A distinct difference between the two controls in the reducing ability was observed. No such difference was found between the obligate and possible heterozygotes on the one hand and the controls on the other. To test the influence of the residual serum in the mixed blood cultures, the serum of a patient's blood sample was replaced by the serum of a control. The frequency of fragile X chromosomes was not decreased by this procedure. Therefore a soluble factor is supposed to exist which is produced by normal or heterozygote cells in culture and which reduces the expression of fragile sites in patient cells.     

Taxonomic relations between archaebacteria including 6 novel genera examined by cross hybridization of DNAs and 16S rRNAs

DNAs from 16 species of archaebacteria including 6 novel isolates were hybridized with 16S rRNAs from 7 species representing different orders or groups of the urkingdom of archaebacteria. The yields, normalized for the number of genes per microgram of DNA, and the temperature stabilities of all hybrids were determined and related to each other. A taxonomic tree constructed from such fractional stability data reveals the same major divisions as that derived from comparative cataloging of 16S rRNA sequences. The extreme halophiles appear however as a distinct order besides the three known divisions of methanogens. The methanogens, the halophiles and Thermoplasma form one of two clearly recognizable branches of the archaebacterial urkingdom. The order represented by Sulfolobus and the related novel order Thermoproteales form the other branch. Three novel genera, Thermoproteus, Desulfurococcus and the "stiff filaments" represent three families of this order. The extremely thermophilic methanogen Methanothermus fervidus belongs to the Methanobacteriales. SN1, a methanogen from Italy, appears as another species of the genus Methanococcus. Another novel methanogen, M3, represents a genus or family of the order Methanomicrobiales.