Biosynthesis of triacylglycerols containing ricinoleate in castor microsomes using 1-acyl-2-oleoyl-sn-glycero-3-phosphocholine as the substrate of oleoyl-12-hydroxylase

We have examined the biosynthetic pathway of triacylglycerols containing ricinoleate to determine the steps in the pathway that lead to the high levels of ricinoleate incorporation in castor oil. The biosynthetic pathway was studied by analysis of products resulting from castor microsomal incubation of 1-palmitoyl-2-[¹⁴C]oleoyl-sn-glycero-3-phosphocholine, the substrate of oleoyl-12-hydroxylase, using high-performance liquid chromatography, gas chromatography, mass spectrometry, and/or thin-layer chromatography. In addition to formation of the immediate and major metabolite, 1-palmitoyl-2-[¹⁴C]rici-noleoyl-sn-glycero-3-phosphocholine, ¹⁴C-labeled 2-linoleoyl-phosphatidylcholine (PC), and ¹⁴C-labeled phosphatidylethanolamine were also identified as the metabolites. In addition, the four triacylglycerols that constitute castor oil, triricinolein, 1,2-diricinoleoyl-3-oleoyl-sn-glycerol, 1,2-diricinoleoyl-3-linoleoyl-sn-glycerol, 1,2-diricinoleoyl-3-linolenoyl-sn-glycerol, were also identified as labeled metabolites in the incubation along with labeled fatty acids: ricinoleate, oleate, and linoleate. The conversion of PC to free fatty acids by phospholipase A₂ strongly favored ricinoleate among the fatty acids on the sn-2 position of PC. A major metabolite, 1-palmitoyl-2-oleoyl-sn-glycerol, was identified as the phospholipase C hydrolyte of the substrate; however, its conversion to triacylglycerols was blocked. In the separate incubations of 2-[¹⁴C]ricinoleoyl-PC and [¹⁴C]ricinoleate plus CoA, the metabolites were free ricinoleate and the same triacylglycerols that result from incubation with 2-oleoyl-PC. Our results demonstrate the proposed pathway: 2-oleoyl-PC. Out results demonstrate the proposed pathway: 2-oleoyl-PC→2-ricinoleoyl-PC→ricinoleate →triacylglycerols. The first two steps as well as the step of diacylglycerol acyltransferase show preference for producing ricinoleate and incorporating it in triacylglycerols over oleate and linoleate. Thus, the productions of these triacylglycerols in this relatively short incubation (30 min), as well as the availability of 2-oleoyl-PC in vivo, reflect the in vivo drive to produce triricinolein in castor bean.     

Tuning Electronic Ground States by Using Chemical Pressure on Quasi-Two Dimensional β′′-(BEDT-TTF)4[(H3O)M(C2O4)3]·Y

We report high-field magnetotransport studies on quasi-two dimensional β′′-(BEDT-TTF)₄[(H₃O)M(C₂O₄)₃]· Y where Y is a solvent in the anionic layer. By changing the size of the solvent the low temperatures electronic behaviour varies from superconducting (for larger solvents, Y = C₆H₅NO₂ and C₆H₅CN) to metallic (for smaller solvents, Y = C₅H₅N and CH₂Cl₂). These changes in the ground state are connected with modications of the Fermi surface, which varies from having one or two pockets for the superconducting charge- transfer salts to at least four pockets in the case of metallic ones. When superconducting, the materials have very large in-plane critical fields (up to 32 T) and enhanced effective masses compared with the metallic compounds. The role of the charge-order fluctuations in stabilizing the superconducting ground state and the effects of intrinsic local disorder is discussed.     

An experimental evaluation of an organizational incentive plan in the electric utility industry.

Results of the present study are based on comparisons between a division in an electric utility company that implemented an organizational incentive plan and another division in the same company that served as a control group. The data indicate that the experimental division performed better than the control division on 11 of 12 objective measures of performance. Results from a pretest–posttest survey of employees in both divisions, as well as a posttest survey in the experimental division, also provide some support for the effectiveness of the organizational incentive plan. Even though the pilot plan proved successful, it was not continued because of conflict between the union and management. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frequency spectrum of focused broadband pulses of electromagnetic radiation generated by polarization currents with superluminally rotating distribution patterns

We investigate the spectral features of the emission from a superluminal polarization current whose distribution pattern rotates (with an angular frequency omega) and oscillates (with a frequency omega > omega differing from an integral multiple of omega) at the same time. This type of polarization current is found in recent practical machines designed to investigate superluminal emission. Although all of the processes involved are linear, we find that the broadband emission contains frequencies that are higher than omega by a factor of the order of (omega/omega)2. This generation of frequencies not required for the creation of the source stems from mathematically rigorous consequences of the familiar classical expression for the retarded potential. The results suggest practical applications for superluminal polarization currents as broadband radio-frequency and infrared sources.     

Lack of effect of epidermal growth factor treatment in late-pregnant ewes on subsequent lactation

Twin-bearing ewes were treated with epidermal growth factor (EGF) to determine its effect on mammogenesis and resultant milk production and composition. The EGF was infused intravenously at a dose rate of 0.5 mg/d in 300 ml saline between days 117 and 139 of gestation; control animals received placebo infusions of saline. All animals then received continuous infusions of 300 ml/d saline on days 139-144. Following parturition 1-5 d later, ewes were milked by hand for 10 d and thereafter were machine-milked until day 16 of lactation. At this level of treatment, EGF was not detected in the circulation during infusion and feed intake was not affected. All ewes gave birth to healthy twin lambs. There were no effects of EGF on birth weights of lambs, live weights of ewes or lengths of gestation. An EGF-immunoreactive material was detected in the mammary secretions of control ewes at a mean concentration of 2 micrograms/l on day 1 of lactation. Two ewes had detectable levels on day 2, but none was found in the milk thereafter. In the EGF-infused group, concentrations of EGF in colostrum were approximately 10 times higher than in the control ewes on day 1 of lactation and EGF was detected in mammary secretions on day 2 but not in subsequent milk samples. A range of 0.3-0.5% of the EGF infused appeared in mammary secretions over the first 2 d of lactation. No other differences were observed for colostrum composition, subsequent milk yield or composition between the two groups of ewes indicating that mammary gland development and function were unaffected. The levels of EGF observed in the mammary secretions of treated and control ewes indicate that the mammary glands accumulate and store EGF in the pre partum period.     

Aquatic bacterial populations and heavy metals—I. Composition of aquatic bacteria in the presence of copper and mercury salts

The effects of addition of copper (in copper sulfate) and mercury (in mercuric chloride) on the naturally occurring bacterial populations of two aquatic systems were studied. Water from each system, one brackish and one fresh water, was brought into the laboratory, and after one week stabilization period at room temperature was treated with metals. The impact of the elements was evaluated by comparing total colony forming units (TCFU), percentages of chromagenic organisms, and numbers of different colony types (diversity) in the laboratory system control with these parameters after additions of Cu and Hg.After stabilization, control (untreated) systems maintained stable TCFU counts throughout the 14-day test period. When either metal was added, an increase in TCFU occurred, a reduction in diversity was noted, and the percentage chromagens in the population varied. Similar results were observed when the elements were added simultaneously to a single system. These results indicate that heavy metal addition reduces bacterial community stability by the reduction in diversity coincident with increased TCFU of surviving organisms.     

Fat emulsion. Effect of heat on solubility of hydrophilic emulsifiers

Summary The bonds between some water-soluble emulsifiers and water are hydrogen bonds with low energies of dissociation, of the order of 7 kcal./mole. In the absence of other factors such bonds can be broken by the kinetic energy of motion at elevated temperatures. The solubility of several emulsifiers was determined, and emulsions containing these emulsifiers at concentrations 2 to 4 times the amount required to make a monomolecular film of the oil droplets were made. To provide emulsion stability at homogenization and sterilization temperatures the emulsifiers must be more hydrophilic than many oil-in-water emulsifiers that are satisfactory in ordinary use and must have an increased affinity for water in the temperature range of 5° to 120°. For a given type of emulsifier containing a given alkyl group, an optimum weight percentage of polyoxyethylene groups is required. The solubility of an amine type emulsifier with the same alkyl group and approximately the same weight percentage of polyoxyethylene groups per molecule is greater than that of the corresponding amide compound, which, in turn, is more soluble than the corresponding ester type of emulsifier, because of differences in chemical type. Polyethylene-propylene oxide had the longest solubility range of the emulsifiers tested. An increase in particle size or an appearance of two phases in emulsions prepared with emulsifiers which undergo solubility inversion below 85° was found. Emulsions prepared with emulsifiers whose inversion temperatures were above 85° maintained, generally, a low particle size on autoclaving, did not separate into a watery phase and an emulsion phase, and did not form a layer of oil. Emulsions prepared with two emulsifiers, such that one had some lipophilic characteristics stronger than the other, were found to be stable and maintain a low particle size on autoclaving. This investigation was supported in part by funds from the Office of Surgeon General. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Suspensions of high-melting triglycerides

A method for preparing stable oil/water suspensions of cottonseed stearine, tristearin, tripalmitin, trimyristin, methyl stearate, and palmitic acid in concentrations up to 10% with minimum concentrations of stabilizing agents is described. Using 2.5% of polyethylene glycol 400 monostearate (based on weight of hard fat), 0.1% of Pluronic F 68, and 0.2–0.25% of Carbopol 934 (the concentrations of these two agents are based on the weight of the aqueous phase), suspensions of the hard fats were prepared by simple stirring, were stable for at least one month at room temperature, and could be sterilized. The size of the dispersed fat particles was 20–40 μ. Apparent viscosities of cottonseed stearine suspensions at 2, 5, and 10% concentrations were 3.59, 5.95, and 6.62 poises at 25C, respectively. Suspensions as described should have utility in those areas of investigation in which solid fatty materials in the form of stable dispersions are desirable. Presented at the AOCS meeting in New Orleans, La., 1962. This work was supported by funds of the Office of the Surgeon General, U. S. Army, Washington, D. C. A laboratory of the So. Utiliz. Res. & Dev. Div., ARS, U.S.D.A.     

Ergonomics and community needs

In this article the Chairman of The Ergonomics Research Society considers, from the background of a recent study conference, some of the current changes in technology and the community, some resultant ergonomics problems, and how ergonomics resources should be better applied to serve community needs.