Aggregated Forms of Glucose-6-phosphate Dehydrogenase from Cultured Rice Plant Cells

Multiple molecular forms of glucose-6-phosphate dehydrogenaseincluding aggregated ones were observed in rice plant suspensioncultures by disc electrophoresis. By sucrose density gradientcentrifugation, the enzyme was resolved into three componentswith the sedimentation coefficients of 42.5, 23 and 6, respectively.The first two components were dissociated into the third componentin the presence of KC1, NADP⁺ and NADPH. These three componentswere interconvertible molecular species. (Received September 16, 1980; Accepted December 19, 1980)     

Hormonal effect on glycoproteins and glycosaminoglycans in rabbit uteri

The effect of the female hormones on glycoproteins and glycosaminoglycans in uteri has been studied.The uteri taken from the ovariectomized rabbits treated with estrogen, estrogen plus progesterone, and sham administration (control) were incubated in vitro with [U-¹⁴C]glucose. Subsequently, the tissues were digested extensively with pronase, yielding crude glycan fractions. The amount and radioactivity of the crude glycan fraction increased by the treatment with estrogen, but reduced to certain level with progesterone.Separation of glycoproteins and glycosaminoglycans was achieved by stepwise elution from Dowex 1 (X2, chloride form) with increasing concentration of NaCl. The yield and radioactivity, together with the results of chemical, enzymatic, and electrophoretic studies on the resulting fractions indicated that the metabolism of a slightly acidic glycoprotein, hyaluronic acid, sulfated glycoproteins, low-sulf ated chondroitin sulfate, heparan sulfate, chondroitin 4-sulfate, and dermatan sulf ate were stimulated remarkably with estrogen, but the stimulation was restored to certain level with progesterone. The degree of the change with these hormones was, however, found to be different from each other. It was noticed that sulfated glycoproteins were the most sensitive to the hormones. On the other hand, the estrogenic stimulation of the metabolism of a neutral glycoprotein and oversulfated chondroitin sulfates was not restored with progesterone.     

Molecular cloning of chick liver HMG 2a cDNA and developmental expression of HMG 2a mRNA.

The cDNA clone encoding HMG 2a of chick liver was isolated from a lambda gt11 expression library using polyclonal antibodies. DNA sequence analysis revealed an open reading frame of 201 amino acids. Comparison of the nucleotide sequences of cDNA coding for chick liver HMG 2a with pig thymus HMG 2 and human monocytic leukemia cell HMG 2 showed 70% homology. 2.0 kb and 1.2 kb mRNAs were found in newly hatched chick liver and decreased during postnatal development of chicks.     

Occlusion-reperfusion model of cerebral ischemia in Fischer 344 rats]

The effect of transient cerebral ischemia (from 15 to 180 min) by bilateral carotid arterial occlusion on postischemic mortality rate and the signs of nervous disorder in Fischer 344 rat was studied. Total mortality rate was 40 to 60% during 72 hr of reperfusion following 2 hr ischemia. Postischemic mortality rate did not vary distinctly with 10, 20 and 40 weeks-old.     

The Saccharomyces cerevisiae genes ( CMP1 and CMP2 ) encoding calmodulin-binding proteins homologous to the catalytic subunit of mammalian protein phosphatase 2B

Summary Saccharomyces cerevisiae genomic clones that encode calmodulin-binding proteins were isolated by screening a λgt11 expression library using¹²⁵I-labeled calmodulin as probe. Among the cloned yeast genes, we found two closely related genes (CMP1 andCMP2) that encode proteins homologous to the catalytic subunit of phosphoprotein phosphatase. The presumed CMP1 protein (62999 Da) and CMP2 protein (68496 Da) contain a 23 amino acid sequence very similar to those identified as calmodulin-binding sites in many calmodulin-regulated proteins. The yeast genes encode proteins especially homologous to the catalytic subunit of mammalian phosphoprotein phosphatase type 213 (calcineurin). The products of theCMP1 andCMP2 genes were identified by immunoblot analysis of cell extracts as proteins of 62000 and 64000 Da, respectively. Gene disruption experiments demonstrated that elimination of either or both of these genes had no effect on cell viability, indicating that these genes are not essential for normal cell growth.     

Crystallization of a photosensitive nitrile hydratase from Rhodococcus sp. N-771.

A photosensitive nitrile hydratase from Rhodococcus sp. N-771 has been crystallized in two different crystal forms in its inactive form. One crystal form belongs to an orthorhombic space group P2(1)2(1)2 with unit cell dimensions of a = 117.4 A, b = 145.7 A and c = 52.1 A, and the other form belongs to a hexagonal space group P6(3)22 with unit cell dimensions of a = 110.2 A and c = 412.1 A.