Chlorierte Kohlenwasserstoffe in Brutv?geln aus dem Binnenland Niedersachsens

Zusammenfassung Rückstände chlorierter Kohlenwasserstoffe in Eiern und Lebern von im Binnenland Niedersachsens brütenden Vogelarten — Feldsperling, Mehlschwalbe, Weißstorch, Graureiher, Saatkrähe, Stockente und andere Arten — werden angegeben und deren Abhängigkeit von Brutort, Nahrung und Zugverhalten diskutiert.

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Chlorinated hydrocarbons of some bird species breeding in the inland of Lower Saxony (FRG)

Summary Residues of chlorinated hydrocarbons in eggs and livers of some bird species — Tree Sparrow, House Martin, White Stork, Heron, Rook, Mallard, and further species — are presented. The dependence on place of breeding, food web, and migration is discussed.

     

Plant protoplasts and genetic engineering II

Book Review

Plant protoplasts and genetic engineering IIY.P.S. Bajaj (Ed.), (Biotechnology in Agriculture and Forestry, Vol. 9). Berlin: Springer-Verlag, 1989. 510 pages. DM398.00. ISBN 3-540-50789-2     

Defect of sperm assembly in a neurological mutant of the mouse, wobbler (WR)

In the wobbler (WR) mouse, a neuromuscular mutant characterized by a motoneuron degeneration and male infertility, the cellular basis of the defect in spermiogenesis was studied by light and electron microscopy as well as by lectin binding. Spermatozoa of the wobbler mutant had rounded heads, and their motility was reduced. In histological sections of WR testes, spermatogenesis appeared normal up to the stage of round spermatids, but the elongation and flattening of the nucleus during late spermiogenesis did not occur. Numbers of spermatid nuclei in WR testes were reduced to 70%-80% of controls. The acrosomal marker glycoprotein, peanut agglutinin receptor, was synthesized, but the acrosomal membrane did not attach to the nucleus. The disturbance in spermiogenesis of the wobbler mouse is not due to impaired descent of the testis, nor to a lack of testosterone, and is distinct from that observed in other mouse mutants (quaking, QK; Purkinje cell degeneration, PCD) with combined neurological and spermiogenesis defects.     

The three-dimensional architecture of chromosome fibres in the crane fly

Microtubules of amphitelically oriented sex univalent chromosome fibres were traced in longitudinal serial sections. The investigated chromosomes were from four different cells representing consecutive stages of anaphase segregation. A correlation was found between chromosome movement and a characteristic distribution of free microtubules (fMTs) oriented obliquely with respect to the kinetochore microtubules. During chromosome segregation the proportion of these skew fMTs (the proportion of skew fMTs is a measure of the degree of disorder in the fibre) is higher in the fibre pointing in the direction of movement than in the trailing fibre. The results are discussed in relation to spindle forces. Although the anaphase of amphitelic sex chromosomes is different in several respects (orientation of chromosome fibres, mutual connexion of chromosomes via kinetochore microtubules, spindle elongation occurring simultaneously), the observations on the distribution of fMTs in the chromosome fibres is, in principle, compatible with those previously made on syntelic autosomes.     

Neither an enhancement of autolytic wall degradation nor an inhibition of the incorporation of cell wall material are pre-requisites for penicillin-induced bacteriolysis in staphylococci

In contrast to what has been postulated, penicillin G at its optimal lytic concentration of 0.1 g per ml did not lead to a detectable activation of autolytic wall processes in staphylococci in terms of the release of uniformly labelled wall fragments from cells pretreated with the drug for 1 h. Rather a considerable inhibition of this release was observed. A similarly profound inhibition of the release of peptidoglycan fragments occurred when staphylococci pretreated for 1 h with 0.1 g penicillin per ml acted as a source of crude autolysins on peptidoglycan isolated from labelled normal cells of the same strain. This clearly demonstrated that the overall inhibition of autolytic wall processes caused by penicillin was mainly due to a decreased total autolysin action rather than to an altered wall structure. Furthermore, no substantial penicillin-induced inhibition of the incorporation of ¹⁴C-N-acetylglucosamine into the staphylococcal wall could be observed before bacteriolysis started, i. e., approximately during the first 80 min of penicillin action. These results are not consistent with any of the models hitherto proposed for the action of penicillin.Dedicated to Prof. Dr. Gerhart Drews on the occasion of his 60th birthday     

Three-dimensional structure of a regular surface layer from Pseudomonas acidovorans

The regular surface layer of Pseudomonas acidovorans was investigated by computer processing of a series of tilted view electron micrographs, and a reconstruction of the three-dimensional structure was obtained. The pattern is tetragonal and consists of massive identical subunits, block-like in face-view, which interlock loosely in a simple cobblestone pattern. The square unit cell has a lattice constant of 11 nm. The surface layer pattern of P. acidovorans appears to be more dependent on the underlying membrane for maintaining its integrity than those so far studied in other bacteria.     

Establishment and Growth Kinetics of the Mutant Ehrlich-Lettré Ascites Cell Strain Hd33 In Permanent Suspension Culture1,2

Cells of a mutant in vivo subline of the Ehrlich-Lettré mouse ascites tumour (ELAT) were converted to growth in suspension culture. Kinetic analysis revealed the selective character of the conversion process; without a detectable adaptation period, a fraction of about 2 × 10^-5 of the explanted cells continued to grow in vitro. the resulting, mutant Ehrlich-Lettré ascites cell strain was designated HD33 and propagated uninterruptedly from 1974 on. the corresponding in vivo ELAT subline HD33 was derived from the HD33 ascites cell strain by intraperitoneal retransplantation. In HD33 cell suspension cultures, the population doubling time, the average intermitotic interval, as determined by videomonitoring, and the average duration of the cell cycle, as determined from percentage of labelled mitoses (PLM) data, were all measured at 15 hr. Cell loss and quiescent compartments were insignificant. the duration of the G₁ phase was effectively zero. Both PLM data and [³H]/[¹⁴C] thymidine double-labetling measurements revealed an S-phase duration of between 11 and 12 hr. the G₂ phase lasted 3–5 hr. The HD33 strain differs from comparable suspension strains of wild-type Ehrlich ascites cells in the insignificant role of density-dependent inhibition in growth, and the striking prolongation of the S phase which is associated with an excessive, cytoplasmic storage of glycogen by the mutant cells.     

6-Hydroxytoxol esters and a seco-dammarane derivative from Abrotanella forsterioides

Abrotanella forsterioides afrorded euparin, 6-hydroxytremetone and three 6-hydroxytoxol esters, one of them not being isolated previously. Furthermore a seco-triterpene was isolated. The tribal position of the genus Abrotanella in the Compositae is still an unsolved problem. Morphological investigations suggest that this genus should be transferred from the tribe Anthemideae to the Senecioneae [1,2]. So far two species have been studied chemically; one atforded ent-kaurane derivatives, while both contained euparin and hydroxytremetone [3].