Isolation and identification of spirorenone metabolites from the monkey (Macaca fascicularis)

The plasma level of spirorenone was determined 3 h after 1, 8, 22 and 46 daily oral administrations of 20 mg/kg to two female and two male monkeys ($\text{Macaca fascicularis}$). A fifth animal, female, was treated with eight daily doses of tritium-labelled drug and was completely bled from the carotid vein 4 h after the last administration in order to isolate and identify plasma metabolites.After repeated daily doses of spirorenone the mean plasma level of unchanged drug was 711 ± 213 ng/ml. In the plasma of the fifth animal four radioactively labelled compounds could be detected after extraction and subsequent HPLC separation. Mass spectrometric identification of three of the substances indicated 1,2-dihydrospirorenone, hydroxy-1,2-dihydrospirorenone and the unchanged drug itself.     

Synthesis and biological activity of brassinolide and its 22β,23β-isomer: Novel plant growth-promoting steroids

Brassinolide (2α,3α,22α, 23α-tetrahydroxy-24α-methyl-B-homo-7-oxa-5α-cholestan-6-one), a novel plant growth-promoting steroid isolated from rape pollen, and its hitherto unknown 22β, 23β-isomer were synthesized from a C-24 epimeric 60:40 mixture of 22-dehydrocampesterol (24α-methyl) and brassicasterol (24β-methyl) from oysters. The method of synthesis favored the formation of the 22β, 23β-isomer by better than 4:1. Comparative plant growth-promoting capabilities of brassinolide, both natural and synthetic, and its three side chain $\text{cis}$-glycolic isomers in the bean second internode bioassay showed that the natural and synthetic brassinolides were equally active and caused splitting of the internode at the 0.1 μg level. The least active was the 22β,23β-isomer of brassinolide. The isomers with the 22α, 23α and 24β, and the 22β, 23β and 24β configurations were highly active and were required at about 10 times the concentration of brassinolide to cause the same physiological response. In the bean first internode bioassay, an auxin-induced growth test system which employs isolated bean plant segments, the isomer with 22β, 23β and 24β configuration caused a greater response than brassinolide. Two of the four tetrahydroxy ketones obtained in the synthesis of the isomers were also active in both assays.     

On the role of IS1 in the formation of hybrids between the bacteriophage P1 and the R plasmid NR1

Summary The genomes of bacteriophage P1 derivatives carrying drug resistance genes derived from an R plasmid NR1 were analysed by restriction cleavage and be DNA-DNA hybridization. Two representatives of a class of oversized P1CmSmSu phages were identified as P1 carrying the entire r-determinant of NR1 together with its two flanking, directly repeated IS1. In one case the r-determinant insertion is carried at the site of the residential IS1 of P1, in the other case it is transposed into another region of the P1 genome. Models postulate that the first type resulted from reciprocal recombination within IS1 elements and that the formation of the second type of P1-R hybrid depended both on IS1 mediated transposition and reciprocal recombination. Plaque forming P1Cm or P1CmSm phages are explained as IS1 mediated deletion derivatives of P1CmSmSu, although an alternative model postulates that sometimes P1Cm phages might result from two consecutive transposition events of only one IS1 without involving reciprocal recombination. Secondary P1 derivatives carrying only one IS1 at the site of the original r-determinant or of Cm insertions into P1 must have been produced by reciprocal recombination between the two IS1 flanking the insertions. An implication from this study, that any genetic material carried adjacent to an IS1 element may undergo passive transposition, is discussed.     

Electrophoretic and biochemical studies of human aldehyde dehydrogenase isozymes in various tissues

Four major ALDH isozymes have been identified in human tissues using starch gel electrophoresis and isoelectric focusing. The isozyme bands have been termed as ALDH I, II, III and IV according to their decreasing electrophoretic migration and increasing isoelectric point. The isozymes have been partially purified via preparative isoelectric focusing. Kinetic characteristics of ALDH I and II were found to be quite similar to ALDH enzyme 2 and enzyme 1 described earlier by Greenfield and Pietruszko (Biochem Biophys Acta, $\text{483}$ 35–45 1977). ALDH III and IV showed a very high Km for propionaldehyde (1.0–1.5 mM at pH 9.5) and were not inhibited by disulfiram at pH 9.5. A variant phenotype of ALDH which lacked in isozyme I was detected in various tissues from Japanese individuals. Comparative kinetic properties of normal and variant enzyme are given.     

The metabolic interactions between Paramecium bursaria Ehrbg. and Chlorella spec. in the Paramecium bursaria-symbiosis

In an organism (strain C 1/2 from Dr. P. R. Hayes, Leeds) regarded as a typical representative of the genus Flavobacterium, flexirubin-type pigments have been identified. The Flavobacterium pigments contain structural elements of both, the pigments of the genus Flexibacter and the pigments of the genus Cytophaga. As flexirubin-type pigments seem to have a rather restricted distribution among bacteria, and have formerly proved to be useful chemosystematic markers for the flexibacteria, this new observation may indicate that there is a relatively close phylogenetic relationship between this type of flavobacteria and the Cytophaga-Flexibacter group.     

A fast and simple radiometric assay for adenosine deaminase using reversed-phase thin-layer chromatography

A new quantitative radiometric assay for adenosine deaminase is described. The reaction conditions are similar to those used in other radioassays and are shown to result in an activity which increases linearly with time and with enzyme concentration. An original feature of the technique resides in the use of reversed-phase thin-layer chromatography to separate adenosine from inosine. The separation is complete, fast, and reproducible. Both compounds can be recovered almost quantitatively from the plates. The assay is very simple and allows the determination of up to 36 samples in 3 h.     

H-2 histocompatibility antigens of subcellular membranes of mouse liver

Purified fractions of plasma membrane, Golgi apparatus, rough endoplasmic reticulum vesicles, nuclear envelope, and mitochondria were isolated from mouse liver and the distribution of H-2 histocompatibility antigens determined by indirect radioimmunoassay before and after membrane disruptive treatments. Fractions enriched in plasma membrane (surface membrane) revealed H-2 antigens in highest concentration; disruptive treatments were not necessary to reveal H-2 antigens with surface membranes. In contrast, internal membranes did not possess H-2 antigens which were accessible to antibody. Golgi apparatus fractions or some component of these fractions (e.g. secretory vesicles) possessed the antigens but in a latent form where accessibility was provided by simple rupture of the membrane vesicles. With endoplasmic reticulum, detergent solubilization of the membranes was required before H-2 antigen could be detected. Nuclear envelope preparations contained little or no demonstrable H-2 activity. These results were confirmed by several techniques including immunoprecipitation of labelled solubilized membrane components with anti-H-2 serum and subsequent analysis in SDS-PAGE.     

Ferritin as an exogenous yolk protein in snails

Summary A main yolk component in the oocytes of the pulmonate snailPlanorbarius corneus L. has been isolated and identified as the iron storage protein ferritin by its ultrastructure, iron content, immuunological properties and behaviour in disc electrophoresis. As judged from acrylamide electrophoresis data and ultrastructural observations, yolk ferritin is an exogenous protein which is synthesised in the hepatopancreas and taken up by the oocytes by endocytosis.     

Fusion of two F-prime factors inEscherichia coli studied by electron microscope heteroduplex analysis

Summary A fused F prime factor was obtained from a mating of arecA donor carrying an F' factor containing the genesmetBJF, ppc andargECBH (KLF5) with arecA recipient carrying an F' factor containingatt80, trp andlac (F155). Lysogenization of this fused F-prime factor with cI⁸⁵⁷ h80 phage followed by thermoinduction produced the transducing phages 80dmetBJF and 80dppcargECBH. This kind of fusion provides a general procedure for the construction of transducing phages carrying genes from different regions of theE. coli genome. To understand the mechanism of this fusion, the parental F prime factors (F155 and KLF5) were analyzed by the electron microscope heteroduplex technique.F155 has a length of 176±3 kilobases including two substitutions. The F sequence 0 F-2.8 F has been substituted by 53 kb of chromosomal DNA including thelac operon and the F sequences 8.5 F-16.3 F has been substituted by 27 kb of a chromosomal sequence includingatt80 and thetrp operon.KLF5 contains 221±4 kilobases of DNA (molecular weight, 148 megadaltons). It contains complete F and the segment of theE. coli chromosome frompolA torif. The F sequence 2.8 F-8.5 F known to be involved in F specific recombination inrecA ⁺ andRecA backgrounds occurs twice on KLF5, once at each of the junctions of F DNA with chromosomal DNA. The population of closed circular plasmid molecules extracted from KLF5-containing strains is heterogeneous. It is proposed that this heterogeneity is due to intramolecular recombination events occurring in KLF5 between the duplicated 2.8 F-8.5 F sequences. Such recombination can account for the genetic instability of KLF5 observed in bothrecA ⁺ andrecA hosts. The F sequence 2.8 F-8.5 F (also called ) is one of the characterized integration sequences on F.A model for the fusion of the parental F prime factors is proposed in which recombination between sequences bringsatt80 close to themetBJF genes. This is followed by a deletion of an F'lac factor. The resulting fused F' factor still carries two sequences and is therefore expected to be unstable. The closed circular molecules isolated from the fused F' containing strains show two different sizes of molecules. Genetic and physical analyses of these molecules are in agreement with the predicted instability of the fused F' factor and the existance of the sequence in the 80dmet phages isolated from fused F' and previously analyzed by the electron microscope heteroduplex technique.