Inhibition by palmitoyl CoA of dynein ATPase from sea urchin spermatozoa

ATPase of 14S dynein, extracted from spermatozoa of the sea urchin, Hemicentrotus pulcherrimus, and partially purified by sucrose density gradient centrifugation, was inhibited non-competitively by palmitoyl CoA at concentrations higher than 20 microns, and was stimulated at concentrations between 2 microns and 10 microns. The effects of palmitoyl CoA on dynein ATPase were reversed by bovine serum albumin (1 mg/ml) and spermine (0.1 and 1 mM). Myristoyl CoA exerted effects similar to those of palmitoyl CoA. Short chain fatty acyl CoAs, such as butyryl CoA, propionyl CoA and acetyl CoA, CoA, Na-palmitate, Na-myristate, and palmitoyl carnitine had hardly any effect on dynein ATPase. Palmitoyl CoA failed to inhibit purified CF1 ATPase from chloroplasts of spinach, ATPase of rat liver mitochondria and alkaline phosphatase from calf intestine.

[Genetic studies of hydatidiform mole with 46,XY karyotype (author's transl)]

Complete hydatidiform moles are androgenetic in origin. The majority of them show a 46,XX karyotype, while some are 46,XY. Chromosome analysis of 75 complete moles revealed three (4.0%) to be so. The XY moles, the patients and their husbands were studied for various polymorphic markers, including chromosomal Q-banding heteromorphism, HLA antigen, phosphoglucomutase-1 and esterase D, in order to determine the origin of XY moles. In all of the three XY moles studied, some of the polymorphic markers were not inherited from the patients, but they were exclusively paternal. Thus, these moles were androgenetic in origin. They also showed both homozygous and heterozygous Q-banding patterns in their homozygous chromosome pairs. Therefore, they were of dispermic origin. In conclusion, XY moles are of dispermic origin.

Inhibition of palmitoyl CoA of EDTA- and Mg2+-ATPase of heavy meromyosin from rabbit skeletal muscle

Palmitoyl CoA inhibited EDTA-ATPase of heavy meromyosin (HMM) prepared from rabbit skeletal muscle. The concentration for half maximum inhibition of EDTA-ATPase was about 18 microM. Myristoyl CoA, the other long chain fatty acyl CoA, also inhibited EDTA-HMM ATPase, but CoA and short chain CoA thioesters, such as butyryl CoA, acetoacetyl CoA and acetyl CoA, at 40 microM hardly inhibited EDTA-ATPase. Less than 20% inhibition of EDTA-HMM ATPase was obtained with Na-palmitate and Na-myristate at 40 microM, whereas about 90% inhibition of the enzyme occurred in the presence of 40 microM palmitoyl CoA and myristoyl CoA. Palmitoyl carnitine, as well as carnitine, failed to inhibit EDTA-HMM-ATPase. The inhibition of palmitoyl CoA of EDTA-ATPase was reversed by bovine serum albumin and spermine. Mg2+-HMM ATPase activity was enhanced by palmitoyl CoA at 2, 5, and 10 microM. About a 25% increase in Mg2+-HMM ATPase activity was obtained at 5 and 10 microM. At higher concentrations than 20 microM, the enzyme was inhibited by palmitoyl CoA and the degree of inhibition was related to the concentration of the CoA thioester. At 80 microM, the activity was about 15% of the maximum value. The efficacy of myristoyl CoA on Mg2+-ATPase was almost the same as that of palmitoyl CoA. Mg2+-ATPase activity was not enhanced by CoA, butyryl CoA, acetoacetyl CoA, Na-myristate, Na-palmitate, palmitoyl carnitine, or carnitine at 10 microM, and was hardly reduced by these substances at 40 microM. Serum albumin and spermine also canceled, to some extent, these effects of palmitoyl CoA on Mg2+-ATPase.

[Separation of free and bound radiolabeled antigen using protein A-sepharose CL-4B in hCG radioimmunoassay (author's transl)]

Protein A isolated from Staphylococcus aureus can bind the Fc portion of IgG of several species. We used Protein A coupled to Sepharose CL-4B (Protein A-S) for the separation of antibody-bound and free radiolabeled hCG in the radioimmunoassay, and the results were compared to the double antibody method. One gram of Protein A-S containing 7 mg of Protein A was dissolved in 17.5 ml of 1/15M phosphate buffer saline pH 7.4. Two hundred fifty microliters of this suspension were added to the assay tubes 24 hours after mixing 125I-hCG, anti-hCG and hCG standards or serum samples. After further incubation for 10 minutes at room temperature, the tubes were centrifuged and the radioactivity in the precipitates was measured by a gamma spectrometer. The standard curve obtained by the Protein A-S method was virtually identical to that obtained using the double antibody method. The intra- and interassay coefficients of variation in the hCG radioimmunoassay using the Protein A-S method ranged from 6.6 to 8.2% and from 7.2 to 11.9% respectively, which were close to those obtained by the double antibody method. IgG in serum inhibited the binding of Protein A-S to anti-hCG, and thus it was necessary to dilute the samples more than one-hundred fold. Under these conditions a good correlation exists in the serum hCG levels determined by either the Protein A-S method or the double antibody method. Thus, Protein A-S permitted the rapid separation of antibody-bound and free radiolabeled hCG in the radioimmunoassay and could be substituted for the second antibody.

Effect of dyes on the photodecomposition of pyridoxine and pyridoxamine

Erythrosine, eosine Y, rose bengal, mercurochrome, methylene blue, azure A and azure B accelerated the photodecomposition of pyridoxine and pyridoxamine at pH 5-9, but fluorescein and acid red did not. The photodecomposition of pyridoxine in the presence of erythrosine was greatest at pH 9.0. The singlet oxygen generated by light-excited dyes played a role as a mediator in the decomposition of pyridoxine and pyridoxamine in the presence of dyes was depressed by aminopyrine, sulpyrine and tryptophan. Pyridoxine 3,4'-dioctanoate was stable in the presence of erythrosine.

Electron microscopy of cytodifferentiation and its subcellular steroidogenic sites in the theca cell of the human ovary

The cytodifferentiation and subcellular steroidogenic sites in the theca cell of the human ovary during the follicular phase were investigated using the electron microscopic cytochemistry. Only fibroblast-like cells were seen around or near the primordial follicle. In the theca interna of the secondary and Graafian follicle however there were three different cell types: fibroblast-like cells, theca gland cells (steroid-secreting cells) and transitional cells (partially or incompletely differentiated theca cells). On the other hand the theca externa of these follicles consisted mainly of fibroblast-like cells. The hallmarks of the cytodifferentiation of the theca cell were: 1) the appearance of lipid droplets, 2) a structural change of the mitochondrial cristae from lamellar to tubular form and 3) the appearance and development of smooth endoplasmic reticulum. Reaction products of 3 beta-hydroxysteroid ferricyanide reductase, indicating 3 beta-hydroxysteroid dehydrogenase activity, were localized on tubular or lamellar cristae and inner membrane of the mitochondria, and on the membranes of smooth endoplasmic reticulum in the transitional cell as well as in the theca gland cell of the secondary and Graafian follicle. From these data, it is suggested that the transitional cell has a steroid-secreting activity and also plays an important role in follicular development in human reproduction.

Substituent and solvent effects on the reaction between 2,6-Di-t-butyl-α-(3,5-di-t-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)-p-tolyloxyl (galvinoxyl) and phenols

Rate constants and associated activation parameters for the reaction of galvinoxyl with substituted phenols were obtained in carbon tetrachloride and in cyclohexane-dioxan binary mixtures. Substantial isotope effects were observed for O-deuterated phenols. The rate constants are correlated with σ+ values. These findings are discussed by considering the polar contribution of substituents to the stabilization of the transition states. In the mixed solvents, the kinetic behaviour is well expressed by the equations which are based on the theory of Kondo and Tokura.