Intranukleäre virusähnliche Partikeln in einem Mammakarzinom

Summary By electron microscopic examination of a solid, chiefly scirrhous mammary cancer, 3 kinds of unusual nuclear inclusions were found: (a) Electron dense particles of a 54–80 nm diameter, whose outlines appear mainly hexagonal, which points at an icosahedral structure, (b) Clusters of granules with a diameter of 200–300å, respectively 300–400å, at whose circumference the larger particles appear, (c) Bundles of filaments in close association and continuous with the granules. In all 3 nuclear inclusions there are subunits of 40–45å. The comparison between these results and experiments published suggest that these nuclear inclusions are (a) virus particles, (b) virus at an early stage of development and (c) virus protein subunits.     

Das Auftreten von Viruspartikeln inAbutilon-Chloroplasten

Summary The leaves ofAbutilon striatum v. Thompson infected with chlorosis proved to contain spheroid virus particles of about 800 Å diameter. Each particle consisted of a central dark staining core of about 160 Å. This central core is surrounded by an inner and an outer envelope. The particles are found in the cytoplasm, and there is evidence to show that virus particles are able to penetrate into the chloroplasts.     

Spierule cells inDrosophila species

Summary Spherule cells are restricted to the larval stage and make up 5–16% of cells in the hemolymph. Their morphology varies between species, mainly due to the shape of their inclusions which may be oval (spheroidocytes), polyhedral (crystalloid cells), or clearly crystalline (crystal cells). These inclusions are very rich in tyrosine. They liquefy rapidly in vitro, whereby the cells become hyaline (coagulocytes).Acknowledgments. We thank Mr B. Barandun for excellent technical assistance. This investigation was supported by the Swiss National Science Foundation, grant No. 3.792.076.     

Membrane damage by coelomic fluid fromHolothuria polii (Echinodermata)

Summary Rabbit erythrocyte membranes lyzed byHolothuria polii coelomic fluid, observed under the electron microscope, present lesions consisting of irregular holes which are heterogeneous in size (ranging from 50 Å to 250 Å) and ultrastructurally different from the ring-like structure produced by human complement. The protein pattern associated with the lyzed membrane was also examined.Acknowledgments. I wish to thank Mr F. Veuthey for his excellent technical assistance. I express also my appreciation to Prof. N. Parrinello for advice and discussion. This work was supported partly by grant 3.083-0.84 from the Swiss National Science Foudation and partly (60%) by grant 1984 from Ministero Pubblica Istruzione, Italy.     

Zur Charakterisierung der Siebröhren-Kallose

Summary Callose of sieve plates from the phloem ofVitis vinifera is characterized by a high density of 1.62 and a refraction index of 1.532±0.002. The X-ray diffraction pattern yields 5 diffuse rings, the strongest of which indicates a periodicity of 15.5 Å.     

Photosensitizing furocoumarins: Interaction with DNA and photo-inactivation of DNA containing viruses

Riassunto Le furocumarine possono legarsi in vitro al DNA ed, in misura molto minore, all'RNA. Per irradizione UV (3655 Å) in presenza di psoralene, tre virus a DNA sono stati inattivati, mentre nessun effetto è stato notato su altri tre virus ad RNA.     

Zur Phagozytose strahlengeschädigter Lymphocyten des Thymus

Summary Part of the lymphocytes of the thymus were phagocytized by epithelial and mesenchymal reticular cells in rats after X-ray irradiation of the whole body. The intracellular decomposition is obviously brought about by the two cellular forms in a different way. Pearl-string-like structures — probably nucleoproteids — were found in the cytoplasma in the case of the epithelial cells. On the other hand, numerous cytoplasma inclusions of different size, which are evidently reduced lymphocytic nuclei, could be observed in the case of the mesenchymal cells.     

Crystallographic evidence for the structural isomorphism of deer and beef catalase

Summary 2 crystal forms of deer liver catalase have been grown and analyzed by X-ray diffraction. Both are of space group P2₁2₁2₁ with cell dimensions I: a=88.5 Å, b=140.5Å and c=235 Å; II: a=124 Å, b=128 Å and c=154 Å. The first of these 2 forms appears to be virtually isomorphous with crystals of beef liver catalase.Acknowledgment. This research was supported by the National Institutes of Health, grant GM21 398 and RR00576. The authors also wish to thank Wardens John Kreider and Jack Schweitzer of the Pennsylvania Game and Fish Commission for providing the deer liver.     

Synphilin-1 isoforms in Parkinson’s disease: regulation by phosphorylation and ubiquitylation

Parkinson’s disease (PD) is characterized by the death of dopaminergic neurons and the presence of Lewy bodies in the substantia nigra pars compacta. The mechanisms involved in the death of neurons as well as the role of Lewy bodies in the pathogenesis of the disease are still unclear. Lewy bodies are made of aggregated proteins, in which α-synuclein represents their major component. α-Synuclein interacts with synphilin-1, a protein that is also present in Lewy bodies. When expressed in cells, synphilin-1 forms inclusions together with α-synuclein that resemble Lewy bodies. Synphilin-1 is ubiquitylated by various E3 ubiquitin-ligases, such as SIAH, parkin and dorfin. Ubiquitylation of synphilin-1 by SIAH is essential for its aggregation into inclusions. We recently identified a new synphilin-1 isoform, synphilin-1A, that is toxic to neurons, aggregation-prone and accumulates in detergent-insoluble fractions of brains from α-synucleinopathy patients. Synphilin-1A inclusions recruit both α-synuclein and synphilin-1. Aggregation of synphilin-1 and synphilin-1A seems to be protective to cells. We now discuss several aspects of the neurobiology and pathology of synphilin-1 isoforms, focusing on possible implications for PD. Received 26 July 2007; received after revision 19 September 2007; accepted 15 October 2007     

The membrane attack complex ofXeopus laevis complement

Summary Rabbit erythrocyte membranes lyzed byXenopus laevis serum exhibited a typical ultrastructural complement lesion with an inner diameter of 80±9Å. The protein pattern associated with lyzed membrane is compared to a similar human preparation.Acknowledgments. I wish to thank Dr. I. Hadji-Azimi for her interest and encouragement, and Professor N. Parrinello for critical reading. This work was supported by a grant from the Swiss National Science Foundation (3.083–0.84).     

Elektronenmikroskopische Beobachtungen an den Hülsenarteriolen in der Milz des Hundes

Summary The endothelial cells of sheathed arterioles of dog spleen were found to contain an abundance of intracytoplasmic filaments about 80 Å in diameter. The endothelium is surrounded by a fenestrated clastin skeleton. The sheath cells show signs of phagocytosis. A possible vasomotor function of the endothelial cells is discussed.     

Subatomic and atomic crystallographic studies of aldose reductase: implications for inhibitor binding

The determination of several of aldose reductase-inhibitor complexes at subatomic resolution has revealed new structural details, including the specific interatomic contacts involved in inhibitor binding. In this article, we review the structures of the complexes of ALR2 with IDD 594 (resolution: 0.66 Å, IC50 (concentration of the inhibitor that produced half-maximal effect): 30 nM, space group: P2¹), IDD 393 (resolution: 0.90 Å, IC50: 6 nM, space group: P1), fidarestat (resolution: 0.92 Å, IC50: 9 nM, space group: P2¹) and minalrestat (resolution: 1.10 Å, IC50: 73 nM, space group: P1). The structures are compared and found to be highly reproductible within the same space group (root mean square (RMS) deviations: 0.15 0.3 Å). The mode of binding of the carboxylate inhibitors IDD 594 and IDD 393 is analysed. The binding of the carboxylate head can be accurately determined by the subatomic resolution structures, since both the protonation states and the positions of the atoms are very precisely known. The differences appear in the binding in the specificity pocket. The high-resolution structures explain the differences in IC50, which are confirmed both experimentally by mass spectrometry measures of VC50 and theoretically by free energy perturbation calculations. The binding of the cyclic imide inhibitors fidarestat and minalrestat is also described, focusing on the observation of a Cl^- ion which binds simultaneously with fidarestat. The presence of this anion, binding also to the active site residue His110, leads to a mechanism in which the inhibitor can bind in a neutral state and then become charged inside the active site pocket. This mechanism can explain the excellent in vivo properties of cyclic imide inhibitors. In summary, the complete and detailed information supplied by the subatomic resolution structures can explain the differences in binding energy of the different inhibitors.     

Eine Absorptionsschicht der hohen Atmosphäre?

Summary The varying intensity of the shortest wave-length 2863 Å of the solar spectrum points to the possibility that labile absorption spectra exist in the higher atmosphere. As spectrographs mounted on V-2 rockets have showen that at a height of 55 km an absorption exists around 2800 Å besides the strong Frauenhofer-lines, and as the termination of the solar spectrum at 2400 Å appears remarkably abrupt, we may suspect a new absorption in the high atmosphere, for which possibly the oxides of nitrogen, primarily the NO ₂ ⁺ or the NO⁺ ion, are responsible.     

The potassium channel KcsA and its interaction with the lipid bilayer

The crystal structure of the K⁺ channel KcsA explains many features of ion channel function. The selectivity filter corresponds to a narrow region about 12 Å long and 3 Å wide, lined by carbonyl groups of the peptide backbone, through which a K⁺ ion can only move in a dehydrated form. The selectivity filter opens into a central, water-filled cavity leading to a gating site on the intracellular side of the channel. The channel is tetrameric, each monomer containing two transmembrane a helices, M1 and M2. Helix M1 faces the lipid bilayer and helix M2 faces the central channel pore; the M2 helices participate in subunit-subunit interactions. Helices M1 and M2 in each subunit pack as a pair of antiparallel coils with a heptad repeat, but the M2 helices of neighbouring subunits show fewer interactions, crossing at an angle of about –40°. Trp residues at the ends of the transmembrane helices form clear girdles on the two faces of the membrane, which, together with girdles of charged residues, define a hydrophobic thickness of about 37 Å for the channel. Binding constants for phosphatidylcholines to KcsA vary with fatty acyl chain length, the optimum chain length being C22. A phosphatidylcholine with this chain length gives a bilayer of thickness about 34 Å in the liquid crystalline phase, matching the hydrophobic thickness of the protein. However, a typical biological membrane has a hydrophobic thickness of about 27 Å. Thus either the transmembrane a helices of KcsA are more tilted in the native membrane than they are in the crystal structure, or the channel is under stress in the native membrane. The efficiency of hydrophobic matching between KcsA and the surrounding lipid bilayer is high over the chain length range C10–C24. The channel requires the presence of some anionic lipids for function, and fluorescence quenching studies show the presence of two classes of lipid binding site on KcsA; at one class of site (nonannular sites) anionic phospholipids bind more strongly than phosphatidylcholine, whereas at the other class of site (annular sites) phosphatidylcholines and anionic phospholipids bind with equal affinity.     

Elektronenmikroskopische Untersuchung der phäochromen (chromaffinen) Granula in den Markzellen der Nebenniere

Summary The catechol-containing granules in the adrenal medullary cells (mouse, guinea pig, cat) are true cell organells, clearly distinguished from mitochondria; their size varies over a fairly wide range, the mean diameter being calculated at about 175 mµ in the mouse (osmium-tetroxide-fixation). They have a surrounding membrane of 100 Å thickness; their internal structure is finely granular. On the thin sections, many granules are surrounded by spaces which appear empty under the electron microscope and which are limited by double-membranes; it is most likely thatintra vitam these spaces contain lipids.

---

---

Ausgeführt mit Unterstützung der Friedrich-Baur-Stiftung und der Deutschen Forschungsgemeinschaft.     

Elektronenmikroskopische Untersuchungen an Zellulosefasern nach Behandlung mit Ultraschall

Summary Treating natural cellulose fibres with ultrasonic waves, fine fibrils split off, which easily can be studied with the electronmicroscope. Bundles of cellulose-molecules with various diameters, very frequently 60–70 Å wide, are found. Their length seems not to be limited within the fibres.     

X-ray microanalysis of animal tissues by means of the field emission-scanning electron microscope

Summary With FESEM the X-ray microanalysis of unstained ultrathin sections (600 Å) free of osmium is possible. Deposits in smooth muscle cells of arteriosclerotic aortae show high calcium-peaks already after 80 sec of measurement. No contamination spots were seen after 11 min of measurement on the same point.     

Sporulation and δ-endotoxin synthesis by Bacillus thuringiensis

Bacillus thuringiensis is distinguished from the very closely related Bacillus cereus and Bacillus anthracis by the presence of several plasmid-encoded δ-endotoxin genes. These δ-endotoxins, synthesized as protoxins, are produced in large quantities during sporulation and are packaged into intracellular inclusions. Ingestion of the inclusions by insect larvae leads to protoxin solubilization and conversion to toxins each specific for one of several orders of insects. The toxins form cation-selective channels in the membrane of cells lining the larval midgut with subsequent lethality. In most cases, δ-endotoxin synthesis and sporulation are closely coupled. The latter process in B. thuringiensis is probably virtually identical to that in Bacillus subtilis with the additional use of mother cell sporulation forms of RNA polymerase for the synthesis of the δ-endotoxins. There are other more subtle plasmid-encoded functions or plasmid interactions related to regulating protoxin synthesis. Consideration of both plasmid and chromosomal genes is thus critical for defining this organism.     

A study of irrigation fluids for neurosurgery on brain primary cell cultures

Summary Primary cell cultures from newborn rat brain hemispheres were exposed to different irrigation fluids used in neurosurgery. The cells died after incubation for 5 min with hydrogen peroxide, and the number of cells was drastically decreased after 10 sec of incubation. They shrank after incubation in Elliott's artificial cerebrospinal fluid for 3 h, but the viability as determined by trypan blue exclusion test was not affected. Physiological sodium chloride, Ringer's solution and the culture medium 199 with Hank's salt had no noticeable effect on the viability or morphology of the cells.Acknowledgments. This study was supported by grants from the Medical Faculty of Göteborg and from Statens Naturvetenskapliga Forskningsråd. We want to thank Dr Åke Sellström and Dr Hans-Arne Hansson for valuable discussions.