Types of sesquiterpene-coumarin ethers from Achillea ochroleuca and Artemisia tripartita

In addition to known derivatives, four new sesquiterpene-coumarin ethers were isolated from the roots of Achillea ochroleuca and Artemisia tripartita and identified by ¹H and ¹³C NMR spectroscopy, including lanthanide induced shifts. The new compounds are isofraxidin derived ethers which differ from the previously described derivatives by ring cleavage and methyl migration within the terpenoid unit. The chemosystematic importance of sesquiterpene-coumarin ether accumulation within the two genera is briefly discussed.     

The arrangement of microtubules and the attachment of chromosomes to the spindle during anaphase in tipulid spermatocytes

Analysis of serial sections oriented parallel to the interpolar spindle axis revealed the following results. Autosomes in anaphase of the 1. meiotic division of Pales ferruginea spermatocytes are attached to the spindle in two ways: 1. The short kinetochoric microtubules (kMTs) diverge and interdigitate with the axial mass of non-kinetochoric microtubules (nkMTs). 2. The chromosome surface shows projections which protrude between the mass of nkMTs. — At the level of anaphase plates the concentration of nkMTs is higher than in the interzone. — The lagging sex chromosomes at the equator become stretched by anaphase forces during autosomal movement. — The mean length of nkMTs in metaphase is 3.0±0.1 μm, in anaphase 2.6±0.1 μm, possibly indicating an overall MT shortening in anaphase. Spindle architecture and aspects of anaphase forces are discussed.     

Verteilung der Mikrotubuli in Metaphase- und Anaphase-Spindeln der Spermatocyten von Pales ferruginea

One metaphase I spindle, seven anaphase I spindles of different stages, and one metaphase II spindle were sectioned in series. The ultrastructure of chromosomes was examined and microtubules (MTs) were counted. The main results of the study are summarized as follows: 1. The autosomes move at the periphery of the continuous MTs during anaphase while the sex chromosomes move more or less within this group of MTs. 2. In metaphase the antosomes have few coarse surface projections, in anaphase many, but more delicate projections of irregular shape which seem to transform into regular radial lamellae at the end of movement. 3. In metaphase continuous MTs have no contact with the chromosomal surface, while during anaphase movement continuous MTs lie closer to the chromosomes, and finally arrange themselves between the radial surface lamellae. There they show lateral filamentous connections with the chromosomal surface. 4. The MT distribution profiles of metaphase and anaphase are different. While the highest density of MTs is observed in the middle region of the spindle in metaphase, there are two density zones during autosomal movement, each in one half spindle in front of the autosomes. After the autosomes have reached the poles the distribution profile is again similar to the metaphase condition. The MT distribution in metaphase II is the same as in metaphase I. Possible explanations for these observations are discussed in detail. 5. There is an overall decrease in MT content during anaphase. 6. With the onset of anaphase MTs are seen within the spindle mantle, closely associated with mitochondria. — Several theoretical aspects of anaphase mechanism are briefly discussed.     

The Avena geo-curvature test

Summary The Avena geo-curvature test is a bioassay for auxin-type growth regulators. Etiolated oat coleoptiles are used and the test is conducted in special perspex trays under diffuse daylight. The coleoptiles, with the primary leaves intact, are arranged in grooves on the trays in 4 series of 6 coleoptiles each, and cut to a size of 10 mm. The test substance is applied on an agar strip covering only the lower halves of the apical cut surfaces of each series. After a 4-hour stay in the dark in moist Petri dishes the coleoptile cylinders are shadowgraphed on a 35-mm photographic film. The curvatures are measured from an enlarged projection (10 times natural size) of the shadowgraphs.The lowest IAA concentration which can be determined is around 30 to 60 g/l, i.e. about 1 to 2 ng IAA. The concentration response curves follow a logarithmic course up to 1,000 g/l. The standard error of the mean in a test series comprising 6 coleoptiles is on an average ± 7%. The simple and quick procedures make it possible for a worker to test 60 to 80 fractions a day.Dedicated to Professor Hans Söding on the occasion of his seventieth birthday. The senior author expresses his special gratitude for having been initiated by Professor Söding in the study of auxins.present address: Dpt. of Biology Princeton Univ. Princeton, N. J. 08540, U.S.A.     

Comparative Study of Cultured Burkitt Tumor Cells by Immunofluorescence, Autoradiography, and Electron Microscopy

Cultured Burkitt cells were examined by immunofluorescence, autoradiography, and electron microscopy in an effort to identify the stainable cells with those harboring herpes-type virus particles. Immediately after a 2-hr pulse of (3)H-thymidine, from 30 to 60% of the cells revealed heavy nuclear labeling. In most cases the grains were evenly dispersed, but in about 3 to 5% the grains showed a focal distribution and occasionally they extended into the cytoplasm. Such nuclear foci were rarely seen at 8 hr after the pulse. When the analysis was restricted to preselected immunofluorescent cells, up to 80% showed label at 8 hr and cytoplasmic grains were prominent. To reduce cellular deoxyribonucleic acid (DNA) synthesis, cells were X-irradiated with 3,000 to 6,000 R, and the isotope pulse was applied 1, 4, or 7 days later. Whereas the total number of labeled cells decreased in roughly twofold steps at the respective intervals (from 40 to 10%), the incorporation of (3)H-thymidine into fluorescent cells was not affected by X irradiation. In each series, about 70% of the fluorescent cells contained label when they were examined at 24 and 48 hr after the pulse, whereas at 8 and 72 hr fewer were positive. At the earlier intervals, unlabeled fluorescent cells most likely represented cells which had completed viral DNA synthesis prior to the pulse; at the later intervals, unlabeled fluorescent cells were probably cells which commenced viral replication after the pulse. These data support the conclusion that the immunofluorescent cells are the ones which harbor virus, and also confirm the expectation that the virus is a DNA virus from a member of the herpes group. This conclusion was firmly established by sectioning and electron microscopic examination of individual fluorescent cells, all of which contained numerous virus particles, whereas the nonstained cells prepared in a similar manner were free of them.     

Electronic recording of mosquito activity

Spontaneous locomotor activity of mosquitoes (Aedes aegypti) was tested over twenty-four hour periods using an electronic recording device which gave a permanent time graph of activity. Single mosquitoes were placed on a wire grid with alternate strands connected to the positive and negative poles of an electric circuit. Each time the mosquito moved, the electric current changed and the event was recorded by a pen-writer. The number of peaks per time interval gave the index of activity. Variables which may affect activity include age, physiological state, sex and strain. A distinct activity cycle was evident in both virgin and mated females but not in males; peak activity came in the early evening and activity was lowest in the early afternoon.

---

Zusammenfassung Die spontane lokomotorische Aktivität von Mücken (Aedes aegypti) wurde über 24stündige Perioden mit Hilfe einer elektronischen Registriereinrichtung untersucht, die eine ununterbrochene Zeitschreibung der Aktivität ergab. Einzelne Mücken wurden auf einen Gürtel feiner Drähte gesetzt, deren Stränge abwechselnd zu den positiven und negativen Polen eines elektrischen Stromkreises führten. Jedesmal wenn sich die Mücke bewegte, änderte sich der elektrische Stromfluß; dieses Ereignis wurde von einer Schreibfeder aufgezeichnet. Die Anzahl der Ausschläge pro Zeiteinheit ergab den Aktivitätsindex. Variable, welche die Aktivität beeinflussen, umfassen Alter, physiologischen Zustand, Geschlecht und Abstammung. Bei jungfräulichen wie bei begatteten Weibchen war ein bestimmter Aktivitätszyklus erkennbar, jedoch nicht bei Männchen; der Aktivitätsgipfel lag in den frühen Abendstunden und die Aktivität war am zeitigen Nachmittag am geringsten.

     

Kurze Mitteilungen

Ohne Zusammenfassung     

Beiträge zur Frage der lichtmikroskopischen Sichtbarkeit des endoplasmatischen Retikulums in Pflanzenzellen

Zusammenfassung Die an Innenepidermiszellen der Zwiebelschuppe vonAllium cepa zu beobachtenden schlauchförmigen intraplasmatischen Vakuolen, in der vorliegenden Arbeit kurz als Schläuche bezeichnet, werden näher untersucht. Sie heben sich im Protoplasma im Phasenkontrast als nichtkontrastierte, massearme Zonen ab. Diese Gebilde werden als Elemente des endoplasmatischen Retikulums (ER) angesprochen. Vergleichende Literaturstudien bekräftigen diese Ansicht.An tierischen Zellen wurden mehrfach im positiven Phasenkontrast dunkle, längliche oder netzförmige Gebilde als Elemente des ER erkannt. Die bei Pflanzenzellen auftretenden, äußerlich sehr ähnlichen Gebilde sind dagegen Plasmaleisten. Sie entstehen zwischen vergrößerten vakuolenartigen Elementen des ER.In jedem Fall ist es notwendig, streng zwischen dem ER sensu strictu, welches aus den Membranen und der von diesen umschlossenen intrazisternalen Phase (IZP) besteht, und dem Grundplasma, der extrazisternalen Phase (EZP), in der die Organellen liegen, zu unterscheiden. Im Lichtmikroskop (Phasenkontrast) werden an erwachsenen Pflanzenzellen die Membranen des ER nicht aufgelöst. Wenn die Membranen aber auseinanderweichen und die IZP durch Wasseraufnahme ein größeres Volumen einnimmt, kann man den Kontrastunterschied zwischen IZP und EZP sehen.Wir danken den optischen Werken C. Reichert A. G., Wien, für die leihweise Überlassung einer phasenoptischen Ausrüstung und der Firma Werfft-Chemie, Wien, für das Tetracyclin-Präparat Achromycin- Lederle.     

Semisynthesis of Arg15, Glu15, Met15, and Nle15-aprotinin involving enzymatic peptide bond resynthesis

The semisynthesis of homologues of aprotinin, the bovine pancreatic trypsin inhibitor, is described. The P₁ lysine¹⁵ residue was replaced by two methods. The first procedure, which consisted of two enzymatic steps for the incorporation of other amino acids has previously been described. The second approach consisted of six steps of both enzymatic and chemical nature. The modified inhibitor, in which the lysine¹⁵-alanine¹⁶ peptide bond is hydrolyzed, was used as the starting material. All carboxyl groups of the modified inhibitor were esterified with methanol; the lysine¹⁵ methylester group was then selectively hydrolyzed. Afterward, lysine¹⁵ itself was split off. Arginine, glutamic acid, methionine, andl-2-aminohexanoic acid (norleucine, Nle) were incorporated using water-soluble carbodiimide combined with an acylation catalyst. The methylester group was used to prevent polymerization. The reactive-site peptide bonds were resynthesized using either chymotrypsin or trypsin.