Identification and chromosomal mapping of a third mouse runt-like locus

The Drosophila runt gene, which controls early events in embryogenesis, has been shown to have homologues in human and mouse. The human gene on 21q22 is involved in the t(8;21) associated with acute myeloid leukemia. Two mouse runt-like loci encoding DNA-binding proteins have been identified. We report here the isolation and partial sequence of a molecular clone of a third mouse runt-like locus. By using a panel of somatic cell hybrids and interspecific backcross mice, we map the novel locus to the telomeric region of mouse chromosome 4.     

Primary tissue culture of human adrenocortical Conn's adenomata

Summary Angiotensin II-induced the hypertrophy of the cytoplasmic compartment and significantly increased (5-³H)uridine incorporation into RNA species by Conn's human adult adenomatous cells in primary tissue culture. On its own, bromocriptine, while enlarging only the nucleolar compartment, also intensely stimulated the incorporation of (5-³H)uridine into RNA species by the cultured adrenocortical adenomatous cells. However, an equimolar mixture of angiotensin II and bromocriptine was totally ineffective, eliciting no change in cellular morphometry or isotope incorporation with respect to the control specimens run in parallel.The present findings support the view that bromocriptine can influence the metabolism of Conn's cells directly at the cellular level by acting as an agonist-antagonist of angiotensin.     

Effects of ACTH and 3′,5′-cyclic purine nucleotides on the morphology and metabolism of normal adult human adrenocortical cells in primary tissue culture

Summary Stereological studies showed that treatment of normal adult human adrenocortical cells in primary culture with ACTH or cyclic-AMP for 2 days results in similar increases in the volume of cells, of the mitochondrial and membrane space compartments and of the surface area of the smooth endoplasmic reticulum and mitochondrial cristae, and decrease in the lipid content of the cells. These changes were more marked after 8 days of treatment. Treatment for 2 days with cyclic-GMP had no striking effects on cell ultrastructure, whereas an 8-day treatment led to ultrastructural changes similar to those obtained after 2 days of ACTH-or cyclic-AMP-treatment. A discrete population of untreated cortical cells maintained a slow proliferation that was not effected by exposure to cyclic-GMP, but was significantly increased in cultures treated with ACTH or cyclic-AMP. Radioimmunological studies showed that untreated cortical cells kept secreting progesterone and cortisol and that ACTH, but neither cyclic nucleotide, increased the secretion rate per cell of both hormones. These results assign a major role to cyclic-AMP and a minor one to cyclic-GMP in the mediation of the differentiation-promoting and trophic effects, but not in the steroidogenic effects of ACTH on the human adrenal cortex.The authors wish to thank Miss A. Coi and Mr. G. Gottardo for their technical assistance. These investigations were partly supported by a contract with CNR-Italy (CT 74.00226/115.3439)     

Freeze-preservation of rice cells: A physiological study of freeze-thawed cells

Rice ( Oryza sativa L.) cells returning to in vitro culture after preservation at superlow temperature in liquid nitrogen are characterized by a number of physiological alterations. These include: reduction in respiration and glucose uptake, loss of intracellular potassium, decrease in the cellular level of key metabolites (ATP, glucose-6-phosphate and pyruvate) and fragility of protoplasts following the action of cell wall-degrading enzymes.
Nevertheless, cell growth resumes after a short lag phase (2–4 days) with an actual 70–100% cell survival, thus indicating that the observed damage is not lethal and can be repaired in a short time.     

C1 proteins: a class of high-mobility-group non-histone chromosomal proteins from the fruit fly Ceratitis capitata

1. CM-cellulose chromatography of a fraction soluble in 5% perchloric acid from Ceratitis capitata chromatin yields three proteins, C1a1, C1a2 and C1b, which have been purified to electrophoretical homogeneity. 2. C1a1, C1a2 and C1b analyse like high mobility group (HMG) non-histone chromosomal proteins, although they do not exactly correspond with those from vertebrates. It is proposed that C1 proteins, as well as Drosophila D1 [Rodríguez Alfageme et al. (1980) Chromosoma, 78, 1-31] are representative of a class of insect-specific HMG proteins. Tryptic fingerprints show that C1a1 and C1a2 are very similar, but C1b is a somewhat distinct protein. Circular dichroism studies have shown that these preparations do not appreciably fold on increasing ionic strength. 3. The interactions between DNA and C1 proteins have been studied. These proteins precipitate DNA in 0.15 M NaCl, 0.015 M sodium citrate and the precipitation curves are cooperative. Soluble complexes between C1 proteins and DNA could be prepared in low ionic strength media and their thermal denaturation profiles obtained. C1 proteins do not destabilize DNA under the conditions used to prepare the complexes but the three proteins stabilize DNA to a different degree. From these studies it has been concluded that the association constant of C1b to DNA is smaller than that of C1a1 and C1a2.     

The binding of [3H]R-PIA to A1 adenosine receptors produces a conversion of the high- to the low-affinity state

Kinetic evidence for negative cooperativity on the binding of [3H]R-PIA to A1 adenosine receptors was obtained from dissociation experiments at different ligand concentrations and from the equilibrium isotherm. The dissociation curves indicate that there is an apparent ligand-induced transformation of high- to low-affinity states of the receptor. At concentrations of 18.2 nM R-PIA or higher there was only found the low-affinity state of the receptor. In view of these results equilibrium binding data were analyzed by the usual two-state model (assuming that there is an interconversion between them) and by the negative cooperativity model employing the Hill equation.     

Silver Enhancement of Nickel-Diaminobenzidine as Applied to Single and Double Immunoperoxidase Staining

A reliable and practical method is proposed for increasing sensitivity and detection efficiency of immunocytochemical techniques, based on silver enhancement of the nickel-diaminobenzidine product of the peroxidase reaction. The procedure produces a strong signal at the site of the end product of the peroxidase reaction which is visible as black grains at the light microscopic level. The method has been used to detect peroxidase labeled probes in immunocytochemical tissue preparations and blotting assays and is ideal for the purposes of double staining and photographic documentation.     

To lek or not to lek: mating strategies of male fallow deer

We studied the mating system of fallow deer (Dama dama) for6 years in central Italy. Males in this population could defendterritories that were either single, clumped in leks, or satelliteto leks. The most highly successful males in our study werein leks. When we considered all males, there were no significantdifferences in average copulatory success according to territorytype because many lek males did not achieve any copulations,which were seen in only a few lek territories. The variancein copulatory success, however, was much greater for leks thanelsewhere. Single territories were occupied for shorter timesduring the rut than lek territories. Fighting among males wasmore frequent in the lek, even when we excluded highly successfullek males from the analysis. Chases of nonterritorial malesand harem size were correlated with the number of copulationsachieved by individual males, but did not vary according toterritory type. Copulatory success of some individuals increasedwith age, but there were no age differences among males holdingdifferent types of territories. Satellite males switched tolek territoriality in the course of one rut, but switches fromsingle territory to lek territory were rare. We suggest thatmales in single territories are inferior competitors that selecta low-risk, lowbenefit strategy, whereas those in lek territorieswhere no copulations were seen may be attempting to establishthemselves on the lek to increase their copulatory success infuture years.