Cloning of bacteriophage T5 promoters

Summary Bacteriophage T5 was subjected to combined hydrolysis with the restriction endonuclease PstI and HindIII and the resulting fragments were inserted into the plasmid pBR322. Selection of transformants for Ap^s-Tc^r-phenotype made it possible to screen the hybrid plasmids that contained promoter sequences in the cloned fragments.Two PstI/HindIII fragment, 720 bp (51% of the T5 DNA length) and 1,200 bp (70%) were cloned in this study. Tc^r levels for these plasmids were as high as 18 g/ml and 75 g/ml, respectively. The presence of Escherichia coli RNA polymerase binding sites on both fragments was shown using the nitrocellulose filter assay. These binding sites are situated between 35 bp and 95 bp from the HindIII cleavage site on the 1,200 bp fragment; and within 420 bp from the HindIII site on the 720 bp fragment.Abbreviations Ap ampicillin - Tc tetracycline - bp base pairs - NTPs nucleoside triphosphates - PBB polymerase binding buffer     

Relationships between the physical and genetic maps of a 470 x 10(3) base-pair region around the terminus of Escherichia coli K12 DNA replication

The physical map of the region on both sides of the terminus of Escherichia coli K12 DNA replication (Bouché, 1982) has been related to the following genetic markers: attφ80, trpABCDE, fnr, rac, trg and man. There are 46 kb² per minute between ftrp and man, indicating that conjugative transfer is not slowed down in the region of the terminus. Using this relationship, trg has been mapped to 31.4 minutes and rac was found to extend from 29.6 to 30.1 minutes. The third λ-homologous genetic element of E. coli K12 (Kaiser, 1980), to be called kim, was identified on the map at 34.2 to 34.6 minutes. The specific activities of fragments labeled at the end of a synchronized replication cycle have been measured. They indicate that, for the trp:: Mu strain studied, the ultimately labeled DNA is at 31.2 ± 0.2 minutes. DNA replication may be delayed or slowed down in a region extending 50 kb on either side of this position.     

Effects of disalicylidenepropanediamines on photosynthetic electron transport of isolated spinach chloroplasts

The effects of disalicylidenepropanediamine (DSPD) and disulfo-disalicylidenepropanediamine (sulfo-DSPD) on the photosynthetic electron transport of isolated chloroplasts have been reexamined.     

Cytophotometric Evidence of Non-S-Phase Extra-Dna In Human Neuronal Nuclei

After Feulgen staining with acriflavine-Schiff, the DNA content of glial and neuronal nuclei from various sites of the human CNS (pre- and post-central gyrus, cerebellar cortex and spinal cord) were determined by fluorescence cytophotometry. the specimens were obtained from twelve adult human autopsy cases. Glial cell nuclei always revealed a biomodal DNA distribution pattern with a large 2c and a smaller 4c peak. the 4c peak was most prominent in the cerebellum. A few 8c glial nuclei were found. Neuronal cell nuclei disclosed unimodal DNA histograms with hyperdiploid means in the range 2.2–2.5c (1.8–2.9c for the individual populations). Tetraploid 4c DNA values were not observed, neither in Purkinje cells, nor in pyramidal cells. In eleven out of a total of forty-four slides the higher DNA means of neuronal nuclei were found to be statistically significant (P < 0.05) when compared with a population of 2c hepatocytes on the same slide. The results indicate the existence of some ‘extra DNA’ in human neuronal cell nuclei, the biological significance of which has still to be elucidated. It is however, suggested that it may play an important role in the functional activity of the CNS.     

Über eine als Gastropodenlaich gedeutete Eiablage in einer Schale vonPseudopecten aus dem Lias von Salzgitter

An internal impression of the right valve of Pseudopecten aequivalvis (Sow.) from the Domerium layer (= Lias δ) at a discontinued iron-ore surface mine, Haverlahwiese near Salzgitter, contains bowl-shaped structures which may be interpreted as gastropod spawn. These are compared with similarly formed half-spheres of recent gastropod eggs which are laid on the inner side of a pecten shell.     

Heterogeneity of LSD-displacing factors and multiple types of high affinity LSD-binding sites

Heterogeneity of high affinity LSD-binding sites was confirmed by displacement studies with 2-bromo (+)—LSD and with apamin, a peptide neurotoxin. In line with the concept of multiple binding sites, a number of fractions of putative endogenous ligands could be separated from rat brain extract. The LSD-displacing β-fraction was not detectable in tissues lacking high affinity LSD-binding sites. High affinity dopamine- and serotonin-binding was differentially affected by the β-fraction.     

The treatment of the hepatorenal syndrome with intra-renal administration of prostaglandin E1

Three patients with the hepatorenal syndrome were treated with prostaglandin E₁ administered through a selective renal arterial catheter. Prostaglandin E₁ was given in progressively increasing doses (2 to 100 ng/kg/min) over a 60-minute period. Control plasma prostaglandin E levels were elevated in all three patients, 0.98, 0.91, and 0.83 ng/ml, respectively. At the end of the infusion, plasma prostaglandin E levels had risen to 10.4, 2.63, and 10.3 ng/ml in the three patients respectively. Plasma renin activity increased during the course of the infusion in two of the patients. The plasma aldosterone concentration did not change during the prostaglandin E₁ infusion. Intrarenal prostaglandin E₁ failed to increase urine volume or urinary sodium concentration in three patients with the hepatorenal syndrome.