Neocarzinostatin chromophore: Presence of a highly strained ether ring and its reaction with mercaptan and sodium borohydride

Spectroscopic evidence suggests the presence of a highly strained ether ring (Fig. 1) (possibly an epoxide) in the C₁₂-subunit of the previously determined partial structure $\text{2a}$ (Fig. 2) of the major neocarzinostatin chromophore (NCS-Chrom $\text{A}$) which completes assignment of all the oxygens in the molecule. The main product from mercaptan treatment suggests opening of the ether ring involving the addition of one molecule of mercaptan as well as reduction of the C₁₂-substructure, whereas a parallel two-step reduction occurs on NaBH₄ treatment. Both reactions occur with rearrangement of the C₁₂-substructure and the implication for the mechanism of action of NCS-Chrom $\text{A}$ in DNA strand scission activity is discussed. The evidence suggests a downward revision of the molecular formula for NCS-Chrom $\text{A}$ as well as minor components $\text{B}$ and $\text{C}$ by two protons.     

Study of Chromosomes in the Newborn after Ultrasonic Fetal Heart Monitoring in Labour

The effect of continuous-wave ultrasound on the chromosomes of newborn infants has been investigated. Twenty-four women were studied during labour. The fetal heart was monitored by a Sonicaid FM2 monitor applied to the abdomen, and continuous monitoring undertaken for intervals varying from 1 hour 5 minutes to 9 hours 25 minutes. There was no increase in the number of chromosome aberrations in cultures of blood taken from the insonated babies when compared with controls.     

High Dosage Metolazone in Chronic Renal Failure

Metolazone is a modified quinazolinesulphonamide and in a dose of between 4 and 7·5 mg is an effective diuretic in man with normal renal function. Fourteen patients with non-oedematous stable chronic renal failure (creatinine clearance ranging from 1·2 to 12 ml/min) were given metolazone in doses ranging from 20-150 mg. A noticeable increase in urine flow and sodium excretion occurred, free water clearance increased, and there was a small but significant increase in potassium excretion. No side effects were noted.     

Growth Temperatures and Temperature Characteristics of Aeromonas

Six of the 13 Aeromonas hydrophila, 1 of 10 A. shigelloides, and none of 10 A. salmonicida were found to be psychrophiles. All of the rest of the strains were mesophiles. The mu values (temperature characteristics) could not be used to distinguish psychrophiles from mesophiles.     

Rapid Test for Urease and Phenylalanine Deaminase Production

A rapid urea-phenylalanine medium was effective for the identification of Proteus and, with one exception, Providencia. Most Klebsiella and a few Enterobacter were urease-positive with this method.     

Release of Envelope Glycoprotein from Rabies Virions by a Nonionic Detergent

Treatment of rabies virus with the nonionic detergent Nonidet P-40 resulted in solubilization of viral lipids and in a preferential release of the envelope glycoprotein. The other viral proteins and the viral ribonucleic acid remained associated in "core" particles sedimenting at a rate similar to that of intact virions. After fractionation of treated virus by velocity centrifugation in a sucrose density gradient, the amount of residual glycoprotein recovered in the "core" particle fraction and the extent of contamination of the glycoprotein fraction by other viral components were dependent on the ratio of detergent to viral protein used.     

Isolation and Characterization of Temperature-Sensitive Mutants of Vesicular Stomatitis Virus, New Jersey Serotype

Forty-eight temperature-sensitive (ts) mutants have been isolated from a wild-type strain of the New Jersey serotype of vesicular stomatitis virus (VSV) after exposure to the base analogue mutagen 5-fluorouracil. Of these mutants, 47 have been classified into 6 nonoverlapping complementation groups containing 21, 17, 4, 3, 2, and 1 mutant, respectively (1 mutant remaining unallocated). The ribonucleic acid (RNA) phenotype of 23 of these mutants has been established. Four of the six groups contain one or more mutants unable to synthesize detectable amounts of viral RNA under restrictive conditions (39 C). No complementation was observed in mixed infection with ts mutants from the five established complementation groups of the Indiana serotype of VSV.     

Transport as the Rate-Limiting Step in the Incorporation of Uridine into Mengovirus Ribonucleic Acid in Novikoff Rat Hepatoma Cells

The incorporation of uridine into the nucleotide pool of actinomycin-treated, mengovirus-infected Novikoff rat hepatoma cells in culture follows simple Michaelis-Menten kinetics, and the apparent V(max) and K(m) values are similar to those for uridine transport by uninfected cells. Incorporation of uridine into mengovirus-specific ribonucleic acid (RNA) also follows Michaelis-Menten kinetics, and the apparent K(m) (about 10 mum) is approximately the same as for uridine transport. Inhibition of uridine transport by the presence of adenosine, persantin, or phenethyl alcohol inhibits simultaneously and to the same extent the incorporation of uridine into the nucleotide pool and into viral RNA, without affecting viral RNA synthesis per se. Phenethyl alcohol, however, also inhibits virus maturation. The inhibition of uridine incorporation into the nucleotide pool and into viral RNA is of the simple competitive type, indicating that transport into the cells is the rate-limiting step in the incorporation of uridine into mengovirus RNA. The results also indicate that treatment with actinomycin D or mengovirus infection does not affect uridine transport.     

Distribution of Purple Photosynthetic Bacteria in Wetland and Woodland Habitats of Central and Northern Minnesota

Enrichment cultures for purple nonsulfur and sulfur photosynthetic bacteria were prepared from soil samples collected in central and northern Minnesota. The purple nonsulfur bacteria were found in most wetland soils sampled but were uncommon in woodland and grassland soils. The pH range of the soils in which these bacteria occurred was 3.8 to 7.8, and the oxidation-reduction potential (E(h)) range was +510 to -65 mV. Soils with a pH below 5.0 or an E(h) above +370 mV had few purple nonsulfur bacteria (<10/g of soil). Rhodopseudomonas viridis, a photosynthetic bacterium containing bacteriochlorophyll b, and the purple sulfur bacteria were common only in low-acidity wetland soils that were usually being reduced.     

The Distribution of Crossovers along Unreplicated Lambda Bacteriophage Chromosomes

The distribution of crossovers along unreplicated chromosomes of bacteriophage lambda has been examined by determining the density distributions and genotypes of particles in the progenies of crosses of density-labeled by ordinary parents in the presence of genetic blocks to replication. The Red and Rec systems combined produce crossovers primarily near the ends (especially the right end) of the chromosome. Removal of the generalized lambda recombination functions by red and gam mutations results in loss of these terminal crossovers; coupled with this loss is a disappearance of the differential dependence of recombination frequencies in terminal and central intervals on DNA synthesis. Removal of the bacterial system by a recA mutation results in severe depression of crossing over among unreplicated phage, with the few recombinants produced by the lambda system occurring near the right end.