Selective proliferation of brain kappa opiate receptors in spontaneously hypertensive rats

The binding of tritiated ligands for various opiate receptor subtypes to brain membranes prepared from spontaneously hypertensive rats and normotensive Wistar-Kyoto rats was determined. The density (Bmax) or the apparent dissociation constant (Kd) for the binding of the mu-ligand (naltrexone) and delta-ligand (Tyr-D-Ser-Gly-Phe-Leu-Thr) to brain membranes of hypertensive and normotensive rats did not differ. However, the Bmax for the binding of kappa-ligand (ethylketocyclazocine, EKC) to brain membranes after the suppression of mu and delta-sites by 100 nM each of unlabeled D-Ala2-MePhe4-Gly-ol5-enkephalin and D-Ala2-D-Leu5-enkephalin, respectively, was significantly greater in hypertensive rats compared to normotensive rats. The Kd values for the binding of 3H-EKC in the two groups did not differ. The binding of 3H-EKC in brain regions was in the order: hypothalamus greater than midbrain greater than striatum greater than cortex greater than pons + medulla. The increase in the binding of 3H-EKC in the brain of hypertensive rats compared to normotensive rats was due to increased binding in the hypothalamus and cortex. These results provide for the first time evidence of selective proliferation of kappa-opiate receptors in the brain of hypertensive rats, and suggest that brain kappa-opiate receptors may play an important role in the pathophysiology of hypertension.     

Purifcation and properties of multiple forms of brain acetylcholinesterase (EC 3.1.1.7)

—Approximately 70 per cent of the total AChE of bovine brain tissue was solubilized by repeated homogenization and centrifugation in 0.32 m sucrose containing EDTA. After ammonium sulphate fractionation, application of the enzyme preparation to an agarose affinity gel column effected a 700-fold purification. Subsequent molecular filtration separated three active forms of AChE with molecular weights of 130,000, 270,000 and 390,000 with an average specific activity of 575 mmol of acetylthiocholine hydrolysed/mg of protein/h. The complete procedure represented an approximate 23,000-fold purification of the enzyme from that in the original tissue homogenate. The three forms of AChE exhibited certain differences in properties, including apparent K_m values, pH optima and sensitivity to inhibitory agents. Ancillary studies on less purified enzyme preparations by use of polyacrylamide gel electrophoresis and isoelectric focusing techniques also suggested that brain AChE exists in multiple forms.     

Sulphur and phosphorus requirements of three fungi causing diseases in storage

Summary The effect of different sulphur and phosphorus compounds on the growth and reproduction of three fungi causing storage rot, viz.,Fusarium solani, Botryodiplodia ananassae andMacrophomina phaseoli has been studied. Sixteen different sources of sulphur were used and out of them magnesium sulphate was found to be most favourable for the growth and reproduction of all the three fungi. Sodium sulphite and sodium bisulphite were toxic. Potassium metabisulphite prevented growth ofF. solani and M. phaseoli while it supported moderate growth ofB. ananassae. Only magnesium sulphate could induce the sporulation ofB. ananassae while sporulation and sclerotial development ofF. solani andM. phaseoli respectively varied with the type of sulphur sources used. Optimum concentration of magnesium sulphate was also determined and it was found that the growth and sporulation ofF. solani andB. ananassae were best at 0.375 g/l and 0.75 g/l.M. phaseoli tolerated higher doses of this substance as the best growth and excellent sclerotial development were recorded at 3.0 g/l (the maximum concentration used). Phosphorus was found to be essential for the present fungi as none of them could grow in complete absence of this substance. Onthophosphates and nucleic acid, were found to be favourable sources for growth and reproduction of the 3 organisms.     

Enhancement of gamma-glutamyl transpeptidase expression in bone marrow cells by colony stimulating factors

Studies on blood serum from mammary carcinoma (MC) hosts, which promoted gamma-glutamyl transpeptidase (GGT) expression by normal rat bone marrow cells in liquid culture, were extended to various granulocyte-macrophage colony stimulating factors (CSFs). GGT concentration per cell was found to increase (without change in total cell number) by incubation for 48 h with purified CSF-2 gamma and CSF-1 (but not interleukin-3), with human giant cell elaborated GM-CSF and L-cell conditioned medium, as well as with the 3 MC preparations (host serum, MC extract and MC conditioned medium). GGT-inducing ability (per milligram protein) ranked the 7 preparations in the same order as did their proliferative effect (number of colonies per milligram protein) in the standard mouse bone marrow agar culture system. The quantitative correlation between these two kinds of activities (linear for their logarithmic values) was highly significant, r = 0.976, p less than 0.001. The alkaline phosphatase concentration of bone marrow cells in liquid culture was also increased in the presence of the same 7 preparations, and this again was proportional (r = 0.985, p less than 0.001) to their colony stimulating potential.