Synthesis and release of ATP by soluble mitochondrial F1 in complex with its inhibitor protein during dimethylsulfoxide-water transitions

Soluble mitochondrial F1 and F1 in complex with the natural ATPase inhibitor protein (F1-IP) catalyze the spontaneous synthesis of [gamma-32P]ATP from medium [32P]phosphate and enzyme-bound ADP when incubated in media with dimethylsulfoxide (Me2SO); under these conditions, the synthesized [gamma-32P]ATP is not released into the media, it remains tightly bound to the enzymes [Gómez-Puyou, A., Tuena de Gómez-Puyou, M. & de Meis, L. (1986) Eur. J. Biochem. 159, 133-140]. Some of the characteristics of the synthesized [gamma-32P]ATP were studied in F1 and F1-IP (ATPase activities of 70 and 1-3 micromol x min(-1) x mg(-1), respectively). In Me2SO media, gamma-phosphate of synthesized ATP in F1 or F1-IP exchanges with medium phosphate. From the rates of the exchange reaction, the half-times for hydrolysis of the synthesized ATP in F1 and F1-IP were calculated: 45 min and 58 min for F1 and F1-IP, respectively. The course that synthesized [gamma-32P]ATP follows after dilution of the Me2SO synthetic mixture with aqueous buffer was determined. After dilution, the half-life of synthesized ATP in F1 was less than 1 min. In F1-IP, ATP was also hydrolyzed, but at significantly lower rates. In F1-IP, dilution also produced release of the synthesized [gamma-32P]ATP. This was assayed by the accessibility of [gamma-32P]ATP to hexokinase. About 25% of [gamma-32P]ATP synthesized in F1-IP, but not in F1, was released into the media after dilution with aqueous buffer that contained 20 mM phosphate. Release of tightly bound ATP required the binding energy of phosphate and solvation of F1-IP, however, the particular kinetics of F1-IP were also central for medium ATP synthesis in the absence of electrochemical H+ gradients.     

Lead acid battery storage configurations for improved availablecapacity

Battery storage is a crucial element in alternative energy and electric vehicle systems. Three battery storage configurations: a conventional; a parallel; and a dual, were analyzed for both shallow cycle and deep cycle lead-acid batteries to determine if capacity improvement is achievable. Daily profiles for the weekly irradiance, daily loads, and ambient temperature are simulated. Cycle tests were performed monthly to determine the effect each configuration had on the available battery capacity. Results for each battery type differ. Available capacity was improved using the parallel configuration with shallow cycle batteries and the dual configuration with deep cycle batteries     

An electrical network approach to the analysis of semiconductordevices

A simple electrical network is used to represent the five differential equations describing basic phenomena in one-dimensional semiconductor devices. Both standard and integrated approaches for solving transport equations are developed. Also, an electrical network equivalent for the nonlinear Poisson equation was derived. It allows students to better understand the physical phenomena and the process of computer simulation of such semiconductor devices     

Cyclooxygenase and lipoxygenase arachidonate metabolites synthesized by mouse peritoneal macrophages: in vitro effect of N-phenyllinoleamide from toxic oil samples

N-phenyllinoleamide (NPLA) has been detected as extraneous compound in adulterated cooking oils associated with a unique epidemic disease known as the Toxic Oil Syndrome (TOS). In this communication we report on the action of NPLA on the endogenous cyclooxygenase and lipoxygenase arachidonate metabolism. Results show that mouse peritoneal macrophages (MPM) exposed to 1 mM NPLA for 2 h undergo significant increases of 6-keto prostaglandin F1a, prostaglandin E2, leukotriene B4, 12- and 15-hydroxyeicosatetraenoic acids. MPM prelabelled with 3H-AA showed an enhanced release when exposed to NPLA. Thus, it is concluded that NPLA potentiates AA release from cell membrane phospholipids and the subsequent cyclooxygenase and lipoxygenase oxidative metabolism of this precursor to various eicosanoids. This is in agreement with the implication of peroxidative process mediated by fatty acids anilides in TOS.     

Breast-feeding and the nutritional status of nursing children in Chile

4-Pentafluoroethylumbelliferyl-beta-D-glucoside is proposed as an efficient substrate for human leukocyte acid beta-glucosidase. Its synthesis is described. This substrate was compared directly with 4-trifluoromethylumbelliferyl-beta-D-glucoside synthesized by us earlier and with 4-methylumbelliferyl-beta-D-glucoside which is commonly used for acid beta-glucosidase activity assay. The specific activity of acid beta-glucosidase with 4-pentafluoroethylumbelliferyl-beta-D-glucoside was 3- and 8-fold higher than it was with the substrates mentioned above. The kinetic parameters KM and VMAX for human leukocyte acid beta-glucosidase with the three substrates was determined. One possible application of the newly synthesized substrate is its use in the diagnosis of acid beta-glucosidase hereditary deficiency (Gaucher's disease).     

Pneumothorax. A complication of fine needle aspiration of breast tumors

Of 1,666 patients who underwent fine needle aspiration for breast lumps, 4 developed pneumothorax as a complication. The incidence of this complication in our patients is 1:417. The clinical manifestations were immediate chest pain, shoulder pain and, occasionally, dyspnea that developed later. Observation is sufficient treatment in most patients, and rarely is drainage of the pneumothorax required.     

Galactolipase and chilling sensitivity of plants

We assessed the effects of a dietary protein restriction (5% vs. 20% casein in diet) initiated at conception and imposed during the first 2 weeks of rat gestation on postnatal brain development. At the end of the malnutrition period, protein-restricted animals exhibited significantly smaller fetal body weight and brain cortical thickness than controls. At birth and thereafter, body weight was normalized in the progeny. Similarly, brain weight and cytoarchitecture were normal in postnatal animals. In contrast, we observed, during the first 2 postnatal weeks, several abnormalities of brain development which affected all the studied areas for most of the studied parameters: (i) delayed astrocytogenesis as shown by a reduced GFAP staining; (ii) delayed production of hyaluronan in the extracellular matrix studied with binding of biotinylated hyaluronectin; (iii) abnormal neuronal differentiation as shown by reduced expression of MAP-5 and increased expression of MAP-1; (iv) abnormal synaptogenesis as shown by the increased expression of synaptophysin in the basal ganglia; (v) decreased programmed cell death. In adult prenatally protein-restricted animals, all the above parameters were normalized excepted MAP-1 labeling which remained high. In addition, we observed slight alterations of the ventilatory response to hypoxia in adult animals. The present study demonstrates that early protein malnutrition during embryonic development induces multiple, transient alterations of brain development. However, the almost complete normalization in adults of brain architecture and differentiation as well as our physiological data strongly suggest a remarkable plasticity of the developing brain following an early aggression.