Quantitative evaluation of gel electrophoretic patterns by videodensitometry

Videodensitometry based on television technique has been shown to be suitable for recording gel electrophoretic patterns. Its speed of operation is about 60 times as fast as that of conventional densitometers, whereas the patterns recorded are practically the same.     

Post-transformational rearrangement of an in vitro reconstructed group-A streptococcal erythromycin resistance plasmid

Cleavage of the group-A streptococcal macrolide, lincosamide, and streptogramin B (MLS) resistance plasmid pSM19035 yields 2 fragments [13 and 4 megadaltons (MD)] with EcoRI, and 15 fragments with HindIII, 12 of which are 6 pairs of identical fragments derived from the inverted repeats that comprise about 80% of the pSM19035 genome. The large EcoRI fragment was isolated, ligated, and used to transform the Challis strain of Streptococcus sanguis to erythromycin resistance. Plasmids (pDB101, pDB102, and pDB103) isolated from three different transformants had lower molecular masses than the original large EcoRI fragment. HindIII digestion of these molecules and subsequent analysis of fragment radioactivity distributions indicated the loss of plasmid segments of various sizes. The deletions, all of which occurred in the palindrome, did not affect the level and the inducible nature of pSM19035-determined antibiotic resistance. Only pDB101 retained the unique EcoRI cleavage site. The results of this analysis allowed the construction of an EcoRI and HindIII cleavage-site map of pSM19035 and promise to simplify future studies of genetic functions specified by streptococcal MLS resistance plasmids.     

Studies on the organization of the α-satellite DNA from African green monkey cells using restriction nucleases and molecular cloning

α-Satellite DNA from African green monkey cells was analysed with restriction nucleases in some detail confirming and complementing our earlier results. With EcoRI and HaeIII (or BsuRI isoschizomer), about 25 and 10%, respectively, of the satellite DNA were cleaved into a series of fragments of the 172 bp repeat length and multiples thereof. To allow studies with fragments of homogeneous sequence unit length, HindIII fragments were covalently joined with the plasmid pBR313. After transformation 19 clones were obtained, containing up to three monomer fragments. Nine of the clones were characterized by digestion with EcoRI. Three of these had cleavage sites for this nuclease in the satellite DNA portion. In the six clones tested with HaeIII no cleavage site was detected in the cloned DNA. The results are discussed in relation to the nucleotide sequence data recently published by Rosenberg et al. (1978) and in the context of random and nonrandom processes in satellite DNA evolution.     

Indomethacin inhibition of cell proliferation induced by the phorbolester TPA is reversed by prostaglandin E2 in mouse epidermis in vivo

The proliferative response of mouse epidermis to the phorbolester TPA (10 nmoles) in vivo is completely inhibited by a single topical application of indomethacin one hour before TPA. DNA labeling in normal mouse epidermis is not significantly depressed by the drug. The inhibition can be reversed by applying prostaglandin E₂ (>3 nmoles) simultaneously with TPA, whereas prostaglandin F_2α (100 nmoles) is ineffective. The indomethacin-sensitive event is restricted to the first hour after phorbol ester treatment. TPA-induced skin inflammation is not influenced by the drug. It is proposed that prostaglandin E₂, or a closely related compound, mediates the mitogenic effect of TPA in mouse skin.     

Jagdgebiet und Ern?hrung der Rohrweihe (Circus aeruginosus) in Schleswig-Holstein

Zusammenfassung Die Ausdehnung des Jagdgebietes der Rohrweihe hängt neben dem Beuteangebot und der Struktur des Gebietes vom Stadium und der Größe der Brut ab. Die Jagdgebietsgröße, ermittelt in einem Mäusejahr an 5 Paaren zur Brutzeit, schwankte zwischen 300–900 ha.1973–1975 wurden an 36 Rohrweihenhorsten 1202 Beutereste gesammelt und ausgewertet. Jagdweise, Beutebehandlung sowie das Auswerten der Beuteaufsammlung werden beschrieben. 58 Wirbeltierarten wurden festgestellt. Der prozentuale Anteil von Säugern und Vögeln an der Beute war in den einzelnen Jahren recht unterschiedlich, während der Anteil der Vögel während zweier Jahre 81 bzw. 75% betrug, sank er in einem Mäusejahr auf ca. 20%. Reptilien, Amphibien und Fische sowie Aas und Vogeleier waren im Untersuchungsgebiet von untergeordneter Bedeutung.Die Frage wird diskutiert, ob Rohrweihen, abgesehen von ihrer angeborenen Vorliebe für Vogeleier, als Nahrungs-Spezialisten zu bezeichnen sind. Ferner werden Hinweise aufgezeigt, die auf große Effizienz beim Nahrungserwerb schließen lassen.

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Hunting-area and food of the marsh-harrier (Cirus aeruginosus) in Schleswig-Holstein

Summary The hunting-area of five pairs of the Marsh-harrier during the breeding season has been investigated in a year with a graduation of field voles (Microtus arvalis). The area varied between 300 and 900 ha per pair. The size of the area was influenced by food availability, the structure of the countryside, clutch size and the growth of the nestlings.From 1973 to 1975, 1202 prey remnants and pellets were collected from 36 nests. The hunting and feeding behaviour of the birds are described. 58 species of vertebrates were identified. The percentage of mammals and birds in the prey was very different in each year. The proportion of birds during two years was 81% and 75% respectively. In a year with a small mammal gradation it decreased to 20%. Other vertebrates (reptiles, amphibians and fishes), carrion, and bird eggs were of minor importance in the study area.The question is discussed whether marsh-harriers tend to a genuine food specialisation, except for their innate preference for bird eggs. Furthermore hints are given concerning the great efficiency of predation.

     

The isolation of IS1 and IS2 DNA

Summary DNA of the IS-elements IS1 and IS2 was prepared by digestion of appropriate heteroduplex molecules with endonuclease S1, followed by sucrose gradient centrifugation or gel electrophoresis. The material obtained is homogeneous with regard to size. The length of IS1 DNA is 820±65 nucleotides, the length of IS2 DNA is 1.350±70 nucleotides. IS1 DNA is not cleaved by the restriction endonucleases Eco R1, Hind II or Hind III. IS2 DNA is cleaved once by each of the two latter enzymes. The buoyant density determined by equilibrium centrifugation of Hg-complexes in Cs₂SO₄ corresponds to a GC content of approximately 50%. Labelling with polynucleotide kinase indicates that both IS DNA's have a guanosyl residue at both of their 5-termini.     

Einbau von 14C-mevalonsäurelacton in hopfenbitterstoffe

Labeled mevalonate is incorporated into terpenes and hop bitter compounds by Humulus lupulus. The role of mevalonate as a precursor for the prenyl (3-methyl-but-2-enyl) side chain of the hop bitter compounds is discussed.