Diurnal rhythm of hypophyseal cells in mich. II. Pars intermedia.

By the use of Mac Conaill's lead hematoxylin, periodic acid and Schiff's reagent (PAS, PbH-positive and PAS-positive cells were distinguished in the pars intermedia of the hypophysis in mice. Nuclear volume in PbH-positive and PAS-positive cells in the pars intermedia of the hypophysis in male and female mice under conditions of 12 h light and 12 h darkness shows distinct diurnal rhythmicity. Maximum nuclear volume in PbH-positive cells of the pars intermedia in both sexes was observed at 1800 h, and minimum at 2400 h. In the Pas-positive cells in females maximum nuclear volume was observed at 600 h, and minimum at 2400 h. In males maximal nuclear volume in these cells appears at 2400 h, and minimum at 1800 h. Maximum number of vacuoles in the nuclei of PbH-positive cells in the pars intermedia in both sexes appeared at 1800 h, and minimum at 2400 h. Maximum numbers of vacuoles in the nuclei of PAS-positive cells in females was noted at 1200 h, and minimum at 2400 h. In males the maximum number of vacuoles appeared at 600 h, and minimum at 1200 h. Differences in the number of vacuoles in the nuclei of PAS-positive cells between males and females were also noted.     

Influence of chronic doses of mercuric acetate and lead acetate on the number and activity of Gomori-positive glial cells in the mouse brain.

Intraperitoneal injections of mercuric acetate or lead acetate in doses of 0.2 mg daily during 14 and 21 days caused statistically significant rise in the number of the Gomori-positive glial cells around the third cerebral ventricle of mice. In addition, the nuclei of the Gomori-positive glial cells markedly increased in volume.     

On the evolution of the bacterial major sigma factors

Summary The existence of internal sequence homologies between the N-terminal halves of the gram-negative bacterial major sigma factors and their C-terminal halves, which correspond to minor factors, is reported. In the case of Escherichia-Salmonella sigma-70, an apparent homology was even found between the C-terminal helix-turn-helix DNA-binding motif and the corresponding region of the peptide N half, which, however, is not directly engaged in promoter recognition. It is proposed that major sigma factors may have originated by duplication and fusion of a DNA unit related to the ancestral gene for the whole sigma family. Coevolution of major sigma structures and complex promoters is suggested.     

Tetracyclic triterpenes. Part VI [1] . The synthesis of 4,4,14α-Trimethyl-19 ( 10 → 9β) abeo-steroids. Synthons for the preparation of cucurbitacins

The effective synthesis of 4,4,14α-trimethyl-19 (10 → 9β) abeo-steroids (iv), (v), and (Vl) with two- and five-carbon side chains from lanosterol is described. Their structures were proved on the basis of spectral data. The title compounds are the first synthetic synthons for the preparation of 4,4,14α-trimethyl-steroids with an unnatural configuration.     

Purification and Properties of Deoxyribonucleic Acid Binding Factor Isolated from the Surface of Streptococcus sanguis Cells

Deoxyribonucleic acid (DNA) binding factor (BF) was found in surface fluids from competent and noncompetent cells of Streptococcus sanguis strains Challis, Wicky, and Blackburn. Fluids from noncompetent cells exhibited about 10% BF activity compared with extracts from competent cells. BF from competent Wicky cells was purified to homogeneity by electrophoresis and immunodiffusion. Purified BF preparations exhibited slight endonucleolytic activity, directed mainly against single-stranded DNA. Nucleolytic and DNA binding activities present in purified BF could be separated by polyacrylamide gel electrophoresis. Purified BF was sensitive to proteolytic enzymes and to phospholipase D, and its activity was stimulated in the presence of low Triton X-100 concentrations. The protein component of BF is a single, monomeric polypeptide with a molecular weight of 56,000 and an isoelectric point of pH 5.8. Binding of purified BF to DNA was a very rapid process at the optimum temperature, pH, and ionic strength and led to the formation of fast-sedimenting complexes. Purified BF was tested for several properties. It exhibited higher affinity to single- than to double-stranded DNA. It bound poorly to glucosylated phage T4 and single-stranded, synthetic polydeoxyribonucleotides and did not bind to RNA. It protected single-stranded DNA against nuclease S₁ action but did not protect native DNA against deoxyribonuclease I action. No evidence was found for unwinding activity, using double-stranded DNA as a substrate.     

Absorption of the flavin dimers

The electronic absorption spectra of the flavomononucleotide (FMN) in aqueous solution and in glycerine-water solution with change of the dye concentration have been measured. The FMN dimer absorption spectrum, monomer absorption spectrum, dimerization constant K and molar fraction of the monomer were calculated. It was found that FMN dimerization constants in aqueous solution were K_a = 118.0 l/mol and in glycerine K_g = 20.5 l/mol. In the region of the monomer absorption band two dimer absorption bands appear, in accordance with the Kasha molecular exciton theory.     

Influence of ethanol on glutathione level in the blood, liver and kidneys of Rana temporaria L. in the annual cycle

The effects of single doses (3 g/kg and 9 g/kg) of 35% ethanol, on the glutathione (GSH) contents of the blood, liver and kidneys of Rana temporaria L. were studied in the annual cycle. It was found that the single doses of ethanol generally caused a significant increase of GSH in the blood and liver of males and females of Rana temporaria L. in each period of the annual cycle as compared with the control values. In time, it was found that the same doses of ethanol caused a significant decrease in the GSH content of the kidneys of the male and female Rana temporaria L. during their active land life and a strong increase of this tripeptide during hibernation.