Feulgen banding of heterochromatin in plant chromosomes.

Feulgen bands can be obtained at the sites of constitutive heterochromatin in the chromosomes of Anemone blanda, Fritillaria lanceolata and Scilla siberica, simply by means of a short or extended acid hydrolysis. Extended hydrolysis gives positive bands in A. blanda and F. lanceolata and negative bands in S. siberica. Short hydrolysis gives no bands in A. blanda and S. siberica but gives negative bands in F. lanceolata. The kind of Feulgen banding obtained is not correlated with the type of base richness of the heterochromatin DNA; rather, it is probably due to differences in the associated nucleoproteins.

Circadian variation in the urinary excretion of electrolytes and trace elements in men.

Three-hour urine specimens were collected over a period of 27 hours from 11 healthy adult male subjects. Each specimen was analyzed for Na, K, Ca, Mg, and Zn using atomic absorption spectrophotometry. Each sample was also dialyzed, pH 7.35, and subsequently analyzed for Na, K, P, Ca, Mg, Zn, Fe, Pb, Al, Ni, Cu, Mo, Hg, Cr, Cd, and Mn using a multielemental argon-plasma emission system. The data were evaluated on conventional time plots (chronograms) and as computer-determined "cosinor" plots. A population circadian rhythm with a statistical significance was detected for total Na, K, Ca, and Mg, and for nondialyzable Na, K, P, Ca, Zn, and Mo. For almost every element studied the increase from lowest to highest 3-hour group mean along the 24-hour time scale was more than 100%. The 24-hour excretion of Na, K, Ca, Mg, and Zn appeared in good agreement with the so-called "normals." The nondialyzable levels of Fe, Pb, Al, Ni, Cu, Mo, Hg, Cr, Cd, and Mn were similar to the total urinary excretions reported in the literature.

Coordination of biogenic amines with synaptosomal and vesicular metal ions: equilibrium and spectral studies in model systems.

Thermodynamic equilibrium studies using model systems were carried out on the nature and extent of coordination of twelve different biogenic amines and adenosine-5'-triphosphate (ATP) with the bivalent metal ions, viz., Ca2+ and Zn2+, which occur in the subcellular fractions of the brain, at 25.0 +/- 0.1 degrees C and at an ionic strength of 1.0 (KNO3). In the combined presence of the individual monoamines and ATP the metal ions were predominantly coordinated by ATP in the pH range 3.0 to 6.5 with binding constants (log KML) of 2.84 +/- 0.06 and 3.19 +/- 0.39 for the Ca2+ and Zn2+ chelates, respectively. Each of the monoamines coordinated with the metal-ATP chelate above pH 6. The stabilities of the chelates of some of the amines with Ca2+ -ATP (1:1) system were NE, 2.33 +/- 0.33; AA, 2.24 +/- 0.19; OA, 1.94 +/- 0.29; NMeN, 1.60 +/- 0.22; DA, 2.14 +/- 0.09. Values for the Zn2+-ATP-amine systems were: NE, 8.35 +/- 0.26; OA, 4.53 +/- 0.07; DA, 10.05 +/- 0.39. Absorption spectral studies were carried out in order to examine the nature of coordination of NE, DA, TA, and AA with Cu2+, Fe2+, and Mg2+ ions in the combined presence of ATP. Results of the spectral studies taken together with the (thermodynamic) equilibrium data have indicated that in the pH range of biological interest, the catechol amines (NE and DA) and ATP are both coordinated to the "synaptosomal and vesicular" metal ions. The results further indicated that both the pyrocatechol and the ethanolamine groups of NE might be involved in the coordination of Cu2+. However, the interaction of the ethanolamine group of the NE molecule with the rest of the metal ions was not indicated.

The Giemsa-staining centromeres of Nigella damascena.

The centromere regions of each chromosome in the complement of Nigella damascena (2n equals 2x equals 12) stain differentially with Giemsa at interphase and throughout all the principal stages of mitosis and meiosis. Each centromere is seen to consist of a pair of sister half-centromeres which appear as 2 differentially stained dots. The appearance and behaviour of these dots indicates that they are kinetochores. The technique used does not stain centromeres in other plant species investigated, a fact which shows that the centromeres of Nigella are in some way different. The implications of this observation in relation to centromere polymorphism are discussed.