Entwicklungsgeschichtliche untersuchungen an einer Blattmutante vonHyoscyamus niger L.

Summary The leaf shape of the mutantfiliformis (fil) ofHyoscyamus niger L. is strongly modified by external factors (like nutrition and light) as well as by the height of insertion. The name filiformis refers to thread-like leaves which always occur in the inflorencence; they may also be formed in the vegetative region, especially under short day conditions. Other leaves may have a small rhombic blade or a larger blade with irregular edges and deep incisions. Even pinnate leaves have been found. In contrast to the leaves of normalHyoscyamus, all mutant leaves (hypsophylls included) have a stalk-like basal portion that seems to be homologous to the basal part of the normal blade. This mutant is caused by one recessive factor which is linked neither toann nor topall.the submarginal initials of the normalHyoscyamus blade were always found dividing according to the periclinal-anticlinal type, while in the mutant the activity of the submarginal initials frequently resulted in a primarily biseriate mesophyll (so-called double-edged segmentation).This is apparently the first time that gene control of the mode of submarginal blade growth has been observed. Further differences between mutant and normalHyoscyamus concern the venation, the lengths of palisade cells and of stomata guard cells, the frequency of stomata per mm², and the thickness of the blade.

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Morphologische und statistische Untersuchungen an Zellkernen von Ratten und Mäusen zur Frage einer cytologischen Geschlechtsdiagnostik

Zusammenfassung An Blutausstrichen und Gewebsschnitten von männlichen und weiblichen Mäusen und Ratten wurde das Vorkommen von geschlechtsspezifischen morphologischen Kernmerkmalen untersucht. Die Kerne der neutrophilen Granulocyten weisen bei beiden Arten keine an den Kernanhängen erkennbare Geschlechtsdifferenz auf. An den Kernen der Parenchymzellen wurde für weibliche und auch für männliche Tiere ein positiver Geschlechtsnachweis auf Grund einer charakteristischen Chromatinverteilung geführt.Wir stimmen dem Vorschlag von Th. Lüers (1957) zu, die Begriffe Geschlechts-bestimmung und Geschlechtsdifferenzierung nur in ihrer ursprünglichen Bedeutung zu verwenden.     

Structure of the core oligosaccharide of a rough-type lipopolysaccharide of Pseudomonas syringae pv. phaseolicola.

The core structure of the lipopolysaccharide (LPS) isolated from a rough strain of the phytopathogenic bacterium Pseudomonas syringae pv. phaseolicola, GSPB 711, was investigated by sugar and methylation analyses, Fourier transform ion-cyclotron resonance ESI MS, and one- and two-dimensional 1H-, 13C- and 31P-NMR spectroscopy. Strong alkaline deacylation of the LPS resulted in two core-lipid A backbone undecasaccharide pentakisphosphates in the ratio approximately 2.5 : 1, which corresponded to outer core glycoforms 1 and 2 terminated with either L-rhamnose or 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo), respectively. Mild acid degradation of the LPS gave the major glycoform 1 core octasaccharide and a minor truncated glycoform 2 core heptasaccharide, which resulted from the cleavage of the terminal Kdo residues. The inner core of P. syringae is distinguished by a high degree of phosphorylation of L-glycero-D-manno-heptose residues with phosphate, diphosphate and ethanolamine diphosphate groups. The glycoform 1 core is structurally similar but not identical to one of the core glycoforms of the human pathogenic bacterium Pseudomonas aeruginosa. The outer core composition and structure may be useful as a chemotaxonomic marker for the P. syringae group of bacteria, whereas a more conserved inner core structure appears to be representative for the whole genus Pseudomonas.     

Tumor necrosis factors in 1996

The 6th International Congress on Tumor Necrosis Factors and Related Molecules was held in Faliraki, Island of Rhodes, Greece, 8–12 May, 1996. This review summarizes the topics addressed and highlights some of the major advances presented during the meeting.     

Labeling of insulin with non-radioactive I and application to incorporation of radioactive I for use in receptor-binding experiments by high-performance liquid chromatography

Conditions for the labeling of insulin with radioactive iodine isotopes were investigated by means of incorporation of non-radioactive ¹²⁷I into the peptide. Either the chloramine-T (CT) or lactoperoxidase-hydrogen peroxide (LPO) technique was applied and reversed-phase high-performance liquid chromatography (RP-HPLC) was used for analysis of the reaction products. The LPO method provided the ¹²⁷I-labeled peptide within 15–30 min, whereas the CT alternative yielded the labeled substrate even within 15 s. However, the latter reaction can only be controlled in a reproducible manner with difficulty and undesirad side-reactions became increasingly prominent when t a few seconds. In another experiment, the LPO technique was applied for radiolabeling insulin with ¹²⁵I. The product was first purified by size-exclusion chromatography (SEC) and then subjected to RP-HPLC. SEC yielded two peaks. The smaller one, which eluted at a slightly higher K_d value (accounting for about 14% of total radioactivity) predominantly consisted of material eluting at the column's void volume under the conditions of RP-HPLC, whereas the main SEC fraction (accounting for about 86% of total radioactivity) yielded a single peak, as shown by HPLC. The radioactive material attributable to the main SEC fraction revealed the expected receptor-binding properties, as evidenced by displacement experiments with non-radioactive insulin, as well as the action of tetradecanoyl phorbol acetate on the binding characteristics and thus indicating formation of a labeled hormone retaining biological activity.     

A receptor for protein import into potato mitochondria

Five potential surface receptors for protein import into plant mitochondria were identified by gentle trypsin treatment of intact mitochondria from potato tubers and subsequent preparation of outer mitochondrial membranes. One of them, a 23 kDa protein, was purified to homogeneity and analysed by direct protein sequencing. Copy DNA clones encoding the corresponding polypeptide were isolated with labelled oligonucleotides derived from the amino acid data. The 23 kDa protein shares significant sequence similarity with protein import receptors from fungal mitochondria and contains one of their typical tetratricopeptide motifs. Its integration into the outer membrane is independent of protease accessible surface receptors and not accompanied by proteolytic processing. Monospecific antibodies against the 23 kDa protein significantly reduce import capacity of isolated mitochondria indicating that this component is indeed involved in the recognition or import of precursor proteins. As in fungi, immunological inhibition of protein import with IgGs against a single receptor is incomplete suggesting the existence of other receptors in the outer mitochondrial membrane of plant mitochondria.     

Preparation of Insect Chromosomes for Immunolabeling

We describe a method for isolating chromosomes from testes of the desert locust, Schistocerca gregaria, and their subsequent incubation with antibodies directed against chromosomal proteins. The procedure involves hypotonic pretreatment of the germ cells, centrifugation onto coverslips in a cytocentrifuge and immunolabeling, while still unfixed, using a chromatin-stabilizing buffer. In the present case, an antibody specific for the acetylated isoforms of his tone H4 was tested. After the antibody treatment, the preparations are fixed using formaldehyde, stained with a DNA-specific fluorescent dye and mounted. Analysis of the preparations revealed good preservation of chromosome structure in prophase spermatogonia and late prophase I spermatocytes. Fully condensed chromosomes were not observed and are probably lost during preparation. The bright fluorescence of the autosomes indicates that the reaction between the antibody against acetylated histone H4 and its chromosomal antigen is not impeded. In contrast, the X univalent remained unstained with the exception of a small terminal band. Thus, cytospin preparations of locust germ cells allow high resolution immunolabeling with antibodies against chromosome-associated proteins.