The effect of alkaline pH on the cell growth of six different mammalian cells in tissue culture

The effect of high alkaline pH on the reinitiation of cell growth was studied in six different mammalian cells. We failed to confirm the observation of Zetterberg & Engström, Proc natl acad sci US 78 (1981) 4334 [17] and Exp cell res 144 (1983) 199 [18]. Treatment of quiescent cells at pH 9.5 did not stimulate cell growth when measured by total protein/flask or increase in cell number.     

Leu-enkephalin-stimulated growth hormone and prolactin release in the rat: comparison with the effect of morphine

The effect of Leu⁵-enkephalin on growth hormone (GH) and prolactin (PRL) release was studied $\text{in vivo}$ in the infant rat and compared to that of morphine. In 10 day-old pups, intracerebroventricular injection of Leu⁵-enkephalin (50, 75 and 100 μg) resulted in a dose-related increase in plasma GH; morphine was active as GH releaser at the dose of 5 and 10 μg, but not at 2.5 μg. Pretreatment with naloxone (2 mg/kg ip) suppressed the GH-releasing effect of either Leu⁵-enkephalin (100 μg) or morphine (10 μg). Leu⁵-enkephalin (75 and 100 μg) induced a rise in plasma PRL which was neither dose-related nor antagonized by naloxone; morphine (5 and 10 μg) was active as PRL releaser and its effect was antagonized by naloxone. These results indicate that: 1) Leu⁵-enkephalin stimulates both GH and PRL release; 2) the release of GH by Leu⁵-enkephalin but likely not that of PRL involves specific opiate receptors; 3) morphine releases GH and PRL through specific opiate receptors.     

Interstitial deletion (2)(p13p15)

Summary A dysmorphic 5-year-old girl with severe growth and mental deficiency was studied. She presented a de novo interstitial 2p deletion. Karyotype: 46,XX,del(2)(p13p15).     

The role of Mg2+ in the regulation of the structural and functional steady-states in rat liver mitochondria

A possible relationship between mitochondrial Mg²⁺ levels, structural configurations, and functional steady states has been studied in rat liver mitochondria. The results show that the concentration of mitochondrial Mg²⁺ in respiratory state 4 is definitely higher than in respiratory state 3. The metabolic transition from state 3 to state 4 and vice-versa is associated with reversible influx-efflux of about 10 nmol of Mg²⁺ per mg protein. The net uptake of this aliquot of Mg²⁺ is a necessary condition in order for the metabolic transition to state 4, both structurally and functionally, to occur. This process requires a threshold concentration of external Mg²⁺ greater than 5 mM. The phosphorylative mechanism does not appear to depend on the presence or absence of external Mg²⁺. The role of Mg²⁺ on the attainment and maintenance of the structural and functional steady state 4 seems to be correlated with its regulatory effect on the concentration of the mitochondrial P_i.     

Meiotic transmission of T-DNA genes inArabidopsis thaliana plants and their expression after 5-azacytidine treatment

Arabidopsis thaliana tumors were induced by octopine strain ofAgrobacterium tumefaciens B6S3 and its derivatives with modified T-DNA. Flowering shoots appeared sponta-neously onin vitro cultivated tumors and set seeds. R₁ and R₂ progeny of octopine synthesizing plants segregated in opine synthesis activities 3:1 and 15:1. Octopine synthase activity showed absolute linkage with agropine synthesis in most lines. In R₃ and R₄ progenies, the fraction of octopine synthase and agropine synthesis positive plants was lower than expected, but Mendelian segregation was restored if plants were cultivated on medium with 5-azacytidine. The most probable mechanism of disapearance of opine synthesis is cytosine methylation. The effect of 5-azacytidine lasted for at least next two generations.     

Restes de vertebres et de mollusques continentauxdans le Villafranchien de la Sardaigne

Remains of vertebrates of Villafranchian age have been found in the Nuraghe Su Casteddu (Nuoro, Sardinia) formation. The fossiliferous layer contain a rich fauna of continental molluscs. The composition of the vertebrate fauna is as follows: Rana sp., ? Coluber sp., Aves indet., Episoriculus aff. gibberodon PETENYI, Talpa sp., Chiroptera indet. and Rodentia indet. It is the first discovery of Villafranchian vetebrates in Sardinia.     

A Substrate for Direct Measurement of L-iduronic Acid 2-sulfate sulfatase

Commercially available sodium heparinate has been sequentially treated with methanolic 0.06M hydrogen chloride and nitrous acid. The nondegraded material was separated by gel filtration from the nonsulfated and monosulfated disaccharides produced. The latter ones, obtained in 10% yield, have been used as a substrate for the direct measurement of the enzyme L-iduronic acid 2-sulfate sulfatase present in human plasma and fibroblast homogenates. Studies of the kinetics and pH optimum of the enzyme, by use of plasma of a patient with mucolipidosis II, indicated an apparent K_m of 2.5mM and a pH optimum of 4.6-4.8. The levels of activity in normal plasma and plasma of a patient with Hunter's disease were found to be 20.4 ± 1.22 units (μmol sulfate/24 h/g protein) and 3.25 ± 0.35 units, respectively. In homogenates of cultured skin fibroblasts, the levels were 137.6 ± 10.7 units for normal controls and 6.4 ± 5.1 for patients with Hunter's disease. The plasma of two obligated heterozygotes gave intermediate levels of activity, whereas the plasma of two possible heterozygotes gave either intermediate levels or entirely normal levels of activity.