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A fluorogenic reagent, 4-mercapto-7-methylthio-2,1,3-benzoxadiazole for carboxylic acids, designed by prediction of the fluorescence intensity.

During the course of our studies of the development of fluorogenic reagents having a 4,7-disubstituted benzofurazan structure, we previously proposed 7-acetylamino-4-mercapto-2,1,3-benzoxadiazole (AABD-SH) as a fluorogenic reagent for carboxylic acids. Since then, progress has made it possible to estimate the fluorescence quantum yields of the 4,7-disubstituted benzofurazan compounds on the basis of the PM3 calculation of their S1-T2 energies. Subsequently, a new fluorogenic reagent, 4-mercapto-7-methylthio-2,1,3-benzoxadiazole (MTBDSH) was designed and synthesized. In the presence of condensation reagents, triphenylphosphine (TPP) and 2,2'-dipyridyl disulfide (DPDS), MTBD-SH readily reacted with n-caprylic acid within 1 min at room temperature. The derivatives of five carboxylic acids (n-caprylic acid, n-capric acid, lauric acid, myristic acid, and palmitic acid) were well-separated on a reversed-phase column and were fluorimetrically detected at 519 nm with excitation at 391 nm. The detection limits (S/N = 3) were 2.4-5.0 fmol. Thus, MTBD-SH had properties that were considered to be superior. For carboxylic acids, itwas superior not only to AABD-SH, but also to many other conventional reagents. The superiority was examined in terms of its reactivity and sensitivity and the avoidance of interfering peaks that were derived from the reagent itself or degradation products in the chromatogram.

Carboxylic Acids↗

Kinetics of whole serum and prepurified IgG digestion by pepsin for F(ab')2 manufacture.

An alternative route for the production of polyclonal F(ab')(2) fragments that might be adopted for the facile preparation of antivenoms is assessed in this work. The method involves the digestion of whole serum by free pepsin, which results in reduction of the number of processing steps commonly in use, because it avoids the initial purification of IgG's prior to their proteolytic cleavage by the enzyme. Digestion kinetics of whole serum and caprylic acid prepurified IgG using free pepsin were monitored with SDS-PAGE followed by densitometric analysis and antigen binding activity assay of the digested samples. It was observed that with equal units of pepsin activity, caprylic acid prepurified IgG was digested more rapidly than whole serum but that the overall retention of antigen binding activity was significantly greater in the latter case. The estimated first-order digestion rate parameters were 11.8 and 4.42 microM min(-)(1) for pure IgG and whole serum, respectively. The K(m) value obtained for whole serum digestion was 33 microM and that for pure IgG digestion was 43.5 microM. Calibration with undigested whole serum and pure IgG samples of known concentrations was performed using SDS-PAGE followed by image analysis. A linear relationship was observed between the protein concentration and the respective band intensity within the range of concentrations investigated (0.63-31.2 microM IgG concentration). This technique proved to be relatively rapid, reproducible, and more precise than size-exclusion chromatography as a result of its F(ab')(2)/IgG resolving power. Staining and destaining protocols were reproduced in terms of staining and destaining times, volumes added, and compositions. Furthermore, all digestion experiments were performed in duplicate sets to monitor the extent of variation of the digestion kinetic parameters measured by this method. The results obtained from this technique confirm and quantify previous observations that pepsin digestion of whole serum is slower and easier to control than digestion of pure IgG and results in higher recovery of antigenic binding activity.

Animals↗

Enhancement of colonic drug absorption by the paracellular permeation route.

Colonic absorption of poorly absorbable cefmetazole was shown to increase considerably by the addition of 1% sodium caprate, sodium laurate, and mixed micelles composed of sodium oleate and sodium taurocholate. At 0.25%, their effects were weaker but still significant. Colonic absorption of inulin was also increased by the promoters at a concentration of 0.25%. These results suggest that there is a common route between inulin and cefmetazole absorption, i.e., the paracellular route. Sodium taurocholate, sodium caprylate, and EDTA disodium salts (EDTA-2Na) at 1% enhanced cefmetazole absorption less than caprate, laurate, or mixed micelles, but no such effect was found at 0.25%. The colonic pore radius was determined from the equivalent pore theory using an everted sac procedure. Caprate, laurate, and mixed micelles at 0.25% caused this radius to increase significantly, thus making it possible for inulin to permeate the everted sac from the mucosal to the serosal side. The effects of taurocholate, caprylate, and EDTA-2Na for increasing colonic pore sizes and the degree of inulin permeation were less than those of caprate, laurate, or mixed micelles. The change in the paracellular route is thus considered to result from the increase in pore size.

Animals↗

Development of 7-(N,N-dimethylaminosulfonyl)-5-N-(4-N-aminoethyl)piperazino-2,1,3-benzoxadiazole as a water-soluble fluorogenic reagent for the sensitive liquid chromatographic determination of saturated carboxylic acids.

A reversed-phase high-performance liquid chromatographic (HPLC) method for the femtomole determination of nine saturated carboxylic acids, n-butyric (C4), n-hexanoic (C6), n-caprylic (C8), n-decanoic (C10), lauric (C12), n-tetradecanoic (C14), palmitic (C16), stearic (C18) and arachidic (C20), based on the condensation reaction of these acids with a newly synthesized water-soluble benzofurazan fluorescent reagent, 7-(N,N-dimethylaminosulfonyl)-4-N-(4-N-aminoethyl)piperazino-2,1,3-benzoxadiazole (DBD-PZ-NH2), was developed. The derivatization reaction proceeds with 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide (EDC) in the presence of the catalyst 4-(dimethylamino)pyridine (DMAP). A model derivative of the reagent with n-caprylic acid (C8) was synthesized for fluorescence excitation/emission characterization. Depending on the solvents, including water, methanol, acetonitrile, 1,4-dioxane or N.N-dimethyformamide (DMF), the C8 derivative has a fluorescence emission with a fluorescence quantum yield (phi) ranging from 0.01 to 0.20 in the region from 545 to 580 nm. An exponential increase in phi was observed with increasing acetonitrile content. The calculated detection limits (signal-to-noise ratio = 3:1) of the proposed method for the above nine carboxylic acids were 9.1, 4.0, 2.5, 2.2, 2.0, 1.8, 1.2, 1.0 and 1.3 fmol, respectively. Biological samples including Intralipos 20% and rat plasma were analysed satisfactorily.

Carboxylic Acids↗

Fatty acid metabolism during hypothermic perfusion of the isolated dog kidney.

Perfusion of isolated dog kidneys was performed at 8--12 degrees C using an albumin solution containing caprylic acid (about 6 mmol/l) and long-chain fatty acids (about 0.5 mmol/l). During 48 h the amounts of caprylic acid in the perfusate fell by about 3 mmol, whereas long-chain FFA increased by 0.2--0.3 mmol and small amounts of arachidonic acid appeared. [14C]palmitate or [14C]linoleate--when added--decreased by about 10% in the perfusate. The decrease was mainly due to exchange with kidney phospholipid fatty acids. Only about 0.4% was recovered as [14C]CO2. The amounts of total phospholipids in kidney tissue decreased by up to 10% during the perfusion (when 10% kidney weight gain was taken into account), whereas lysophospholipids, cholesterol, triglycerides and free fatty acids remained essentially unchanged. The distribution of fatty acids in the total phospholipid fraction was strikingly altered. The relative amounts of arachidonic acid increased, whereas all other major fatty acids decreased. Synthesis of arachidonic acid by chain elongation of perfusate [14C]linoleic acid could not be demonstrated, and no evidence was found for a significant increase of the total amounts of arachidonic acid. The possibility that arachidonic acid-containing phospholipids in the kidney are preferentially preserved during the hypothermic conditions is discussed.

Animals↗

Unsaturated fatty acids regulate gene expression of cellular retinol-binding protein, type II in rat jejunum.

We have shown that cellular retinol-binding protein, type II (CRBP II) mRNA and its protein levels are elevated in the jejunum of rats fed a diet rich in long-chain triacylglycerols. In the present study, we explored which types of fatty acids modulate CRBP II gene expression. Rats previously fed a low fat, high starch diet were force-fed a basal fat-free diet or the diet supplemented with 0.21 mol/L of various fatty acids (i.e., caprylic, palmitic, stearic, oleic, linoleic and alpha-linolenic acids). Force-feeding a diet containing linoleic acid produced an elevation of CRBP II mRNA levels in rats in both a dose-dependent (0.053-0.21 mol/L) and time-dependent (up to 6 h) manner. Among fatty acids tested, all unsaturated fatty acids (oleic, linoleic and alpha-linolenic acids) were able to enhance CRBP II mRNA levels by 54-63% within 6 h, whereas a medium-chain fatty acid (caprylic acid) and a saturated fatty acid (stearic acid) elicited little effect on the CRBP II mRNA levels; palmitic acid produced only a small elevation (16%) of the CRBP II mRNA level. Transcripts of both retinoid X receptor alpha and peroxisome proliferator-activated receptor (PPAR), which are thought to interact as a heterodimer with the cis-element located in the CRBP II promoter and to be activated by 9-cis retinoic acid and long-chain fatty acids, respectively, were constitutively expressed in the rat jejunum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Anaphylactoid reactions to infusions of plasma protein and human serum albumin. Role of aggregated proteins and of stabilizers added during production.

Six patients suffering from anaphylactoid reactions after infusion of pasteurized plasma (PP) or human serum albumin (HSA) were investigated. Clinical symptoms ranged from urticaria and hypotension to cardiac arrest. Immunoglobulin levels, especially of IgA, were normal, as were concentrations of complement factors C3, C4 and factor B. In skin and lymphocyte transformation tests patients, with the exception of one severely allergic to protein, did not react to the monomeric pure HSA. Five out of six patients reacted against HSA aggregates and three patients to the HSA modified by caprylate added as stabilizer during commercial HSA production. It is concluded that the anaphylactoid reactions developing after PP or HSA infusion result from a non-specific reaction to protein aggregates and in some cases possibly from a specific immune response to the caprylate-modified HSA.

Anaphylaxis↗

Inhibition of methanogenesis from acetate in granular sludge by long-chain Fatty acids.

The effect of four saturated long-chain fatty acids (caprylic, capric, lauric, and myristic) and one unsaturated long-chain fatty acid (oleic) on the microbial formation of methane from acetate was investigated in batch anaerobic toxicity assays. The tests were carried out with granular sludge from an upflow anaerobic sludge bed reactor. In this sludge, Methanothrix spp. are the predominant acetoclastic methanogens. Lauric acid appeared to be the most versatile inhibitor: inhibition started at 1.6 mM, and at 4.3 mM the maximum specific acetoclastic methanogenic activity had been reduced to 50%. Caprylic acid appeared to be only slightly inhibitory. Oleic acid was almost as inhibitory as lauric acid. Although adsorption of the inhibitor on the cell wall might play an important role in the mechanism of inhibition, the inhibition was found to be correlated with concentration rather than with the amount per unit of biomass. In practical situations, as in anaerobic waste treatment processes, synergism can be expected to enhance the inhibition of methanogenesis. In the present research a background concentration of lauric acid below its MIC strongly enhanced the toxicity of capric acid and (to an even greater extent) myristic acid.

Journal Article↗

Effect of increased yeast alcohol acetyltransferase activity on flavor profiles of wine and distillates.

The distinctive flavor of wine, brandy, and other grape-derived alcoholic beverages is affected by many compounds, including esters produced during alcoholic fermentation. The characteristic fruity odors of the fermentation bouquet are primarily due to a mixture of hexyl acetate, ethyl caproate (apple-like aroma), iso-amyl acetate (banana-like aroma), ethyl caprylate (apple-like aroma), and 2-phenylethyl acetate (fruity, flowery flavor with a honey note). The objective of this study was to investigate the feasibility of improving the aroma of wine and distillates by overexpressing one of the endogenous yeast genes that controls acetate ester production during fermentation. The synthesis of acetate esters by the wine yeast Saccharomyces cerevisiae during fermentation is ascribed to at least three acetyltransferase activities, namely, alcohol acetyltransferase (AAT), ethanol acetyltransferase, and iso-amyl AAT. To investigate the effect of increased AAT activity on the sensory quality of Chenin blanc wines and distillates from Colombar base wines, we have overexpressed the alcohol acetyltransferase gene (ATF1) of S. cerevisiae. The ATF1 gene, located on chromosome XV, was cloned from a widely used commercial wine yeast strain of S. cerevisiae, VIN13, and placed under the control of the constitutive yeast phosphoglycerate kinase gene (PGK1) promoter and terminator. Chromoblot analysis confirmed the integration of the modified copy of ATF1 into the genome of three commercial wine yeast strains (VIN7, VIN13, and WE228). Northern blot analysis indicated constitutive expression of ATF1 at high levels in these yeast transformants. The levels of ethyl acetate, iso-amyl acetate, and 2-phenylethyl acetate increased 3- to 10-fold, 3.8- to 12-fold, and 2- to 10-fold, respectively, depending on the fermentation temperature, cultivar, and yeast strain used. The concentrations of ethyl caprate, ethyl caprylate, and hexyl acetate only showed minor changes, whereas the acetic acid concentration decreased by more than half. These changes in the wine and distillate composition had a pronounced effect on the solvent or chemical aroma (associated with ethyl acetate and iso-amyl acetate) and the herbaceous and heads-associated aromas of the final distillate and the solvent or chemical and fruity or flowery characters of the Chenin blanc wines. This study establishes the concept that the overexpression of acetyltransferase genes such as ATF1 could profoundly affect the flavor profiles of wines and distillates deficient in aroma, thereby paving the way for the production of products maintaining a fruitier character for longer periods after bottling.

Acetates↗

Inactivation of enterohemorrhagic Escherichia coli in rumen content- or feces-contaminated drinking water for cattle.

Cattle drinking water is a source of on-farm Escherichia coli O157:H7 transmission. The antimicrobial activities of disinfectants to control E. coli O157:H7 in on-farm drinking water are frequently neutralized by the presence of rumen content and manure that generally contaminate the drinking water. Different chemical treatments, including lactic acid, acidic calcium sulfate, chlorine, chlorine dioxide, hydrogen peroxide, caprylic acid, ozone, butyric acid, sodium benzoate, and competing E. coli, were tested individually or in combination for inactivation of E. coli O157:H7 in the presence of rumen content. Chlorine (5 ppm), ozone (22 to 24 ppm at 5 degrees C), and competing E. coli treatment of water had minimal effects (<1 log CFU/ml reduction) on killing E. coli O157:H7 in the presence of rumen content at water-to-rumen content ratios of 50:1 (vol/wt) and lower. Four chemical-treatment combinations, including (i) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 0.05% caprylic acid (treatment A); (ii) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 0.1% sodium benzoate (treatment B); (iii) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 0.5% butyric acid (treatment C); and (iv) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 100 ppm chlorine dioxide (treatment D); were highly effective (>3 log CFU/ml reduction) at 21 degrees C in killing E. coli O157:H7, O26:H11, and O111:NM in water heavily contaminated with rumen content (10:1 water/rumen content ratio [vol/wt]) or feces (20:1 water/feces ratio [vol/wt]). Among them, treatments A, B, and C killed >5 log CFU E. coli O157:H7, O26:H11, and O111:NM/ml within 30 min in water containing rumen content or feces, whereas treatment D inactivated approximately 3 to 4 log CFU/ml under the same conditions. Cattle given water containing treatment A or C or untreated water (control) ad libitum for two 7-day periods drank 15.2, 13.8, and 30.3 liters/day, respectively, and cattle given water containing 0.1% lactic acid plus 0.9% acidic calcium sulfate (pH 2.1) drank 18.6 liters/day. The amounts of water consumed for all water treatments were significantly different from that for the control, but there were no significant differences among the water treatments. Such treatments may best be applied periodically to drinking water troughs and then flushed, rather than being added continuously, to avoid reduced water consumption by cattle.

Animals↗

Corneal permeability to bunazosin in rabbits.

Topical and systemic absorption of bunazosin after topical instillation was investigated in rabbits. Corneal permeability of bunazosin in vivo was increased by the addition of caprylic acid in amounts equimolar to bunazosin. Aqueous humor levels of bunazosin were significantly elevated. These results correlated well with those obtained in vitro experiments. Contrarily, the levels of plasma were not significantly affected and only slightly lowered by caprylic acid.

Adrenergic alpha-Antagonists↗

Development and in vitro evaluation of nimodipine transdermal formulations using factorial design.

The in vitro permeation of nimodipine through human cadaver skin, as a preliminary step toward the development of a transdermal therapeutic system, was investigated. In vitro release studies were carried out using modified Franz diffusion cells and human epidermal membrane, taken from full-thickness cadaver skin by heat separation technique. To estimate the effect of the type of enhancer, the concentration of enhancer and the concentration of the gelling agent on the permeation of nimodipine, a 2(3) factorial design was involved. The type of enhancer was further evaluated, because it was found to be important for the permeation of nimodipine; the concentration of enhancer and the concentration of the gelling agent were kept at their optimum levels in all experiments. Six groups of enhancers (alkanols, alkanoic acids, alkanoic acids ethyl esters, caprylic acid alkyl esters, essential oils and some other enhancers) were examined for their ability to increase the permeation of nimodipine. It was found that myristyl alcohol, caprylic acid, L-menthol, and oleic acid gave better permeation rates at 24 hr, with oleic acid being the better enhancer, and higher permeation rates at 48 and 72 hr were achieved only when cineol was used.

Administration, Cutaneous↗

Evaluation of postmilking teat germicides containing Lauricidin, saturated fatty acids, and lactic acid.

The efficacies of postmilking teat germicides containing Lauricidin (glyceryl monolaurate), saturated fatty acids, lactic acid, and lauric acid were determined against new IMI caused by Staphylococcus aureus and Streptococcus agalactiae in three controlled infection trials. In trial 1, a germicide was evaluated containing 1% Lauricidin, 5% caprylic and capric acids, 6% lactic acid, and .85% lauric acid. New IMI with Staph. aureus and Strep. agalactiae were reduced 81.3 and 49.6%, respectively. Trial 2 germicide involved an artificially aged sample of the formulation evaluated in trial 1. The germicide was aged at 40 degrees C for 5 mo, which was approximately equal to 2 yr at room temperature (24 degrees C). Reductions in new IMI were 81.2 and 27.5% for Staph. aureus and Strep. agalactiae, respectively. In trial 3, a teat germicide aged at ambient temperature for 33 mo, which was originally formulated to contain 1% Lauricidin, 5% caprylic and capric acids, and 6% lactic acid, was evaluated. Reductions in new IMI were 75.5 and 40.4% for Staph. aureus and Strep. agalactiae, respectively. The formulation evaluated in trial 1 was superior to other formulations in reducing new IMI by the two test organisms.

Animals↗

[Studies on monoclonal antibody against recombinant human granulocyte colony-stimulating factor].

Three hybridomas producing monoclonal antibodies (McAb) against recombinant human granulocyte colony-stimulating factor (rhG-CSF) have been established by fusing mouse myeloma SP 2/0 cells with spleen cells from a BALB/c mouse immunized with rhG-CSF. Ascites was produced from BALB/c mice by injecting substrain 2D4-B4 hybridoma cells intraperitoneally. The antibody was purified either by the caprylic acid-ammonium sulfate method or by euglobulin precipitation. The caprylic acid-ammonium sulfate method was superior to euglobulin precipitation in terms of purification and recovery of IgG. The 2D4-B4 McAb was determined to belong to the IgG3 subclass with a molecular weight of about 172,400 It was proved by Western Blot to react specifically with rhG-CSF. The stability and affinity of the McAb were analyzed as well. The potential clinical and experimental applications of this McAb are discussed.

Animals↗

Discriminant analysis of free fatty acids of some Egyptian snails as a step for schistosomiasis control: new trends.

Schistosomiasis is still the most common occupational health problem of rural workers in Egypt. The use of molluscicides, either chemical or biological, and environmental changing are the most successful methods of snail control. The new trend in Schistosoma control programs is to study the ecological factors that attract miracidium Schistosoma specific snails, to emphasizing to find out new environmental safe control methods. Since Schistosoma worms do not make fatty acids de novo, they require host lipids for survival and to complete their life cycle. Discriminate analysis of the estimated free fatty acids was done in this study in Biomphalaria alexandrina, Biomphalaria glabrata, and Bulinus truncatus, viz. Lymnaea truncatula and Physa acuta (Schistosoma intermediate and non-intermediate respectively). With the objective of determination of the biochemical difference that attract the infestation of Schistosoma miracidium to the target snails, as a step of the new control trends. Caprylic acid (C8:0), and Oleic acid (C18:1) are significantly lower in the tissues of Schistosoma intermediate snails compared to the non-intermediate snails. While, Capric acid (C10:0), Margaric acid (C17:0), and Lenoleic acid (C18:2) of the intermediate snails are significantly higher than that of non-intermediate snails. The percent of correct medical classification of snails are more than 80% according to Caprylic acid, Margaric acid, and Lenoleic acid, the other 15 fatty acids are less than 80%. These three free fatty acids could be chemoattractive of Schistosoma miracidium, and could be used as safe environmental control compounds, which needs further research.

Animals↗

Preparation and characterization of liposomal-lipophilic tumor necrosis factor.

The liposomal delivery of recombinant human tumor necrosis factor (rHuTNF) has been shown to be effective in reducing its toxic effects and in its targeting of organs rich in cells of the reticuloendothelial system. However, native recombinant human TNF shows only poor affinity for liposomes, presumably due to its low hydrophobicity. In an attempt to increase the efficiency of association with liposomes, we have modified TNF to increase its hydrophobicity by selective substitution of its amino groups with fatty acid side chains. N-hydroxysuccinimide esters of saturated fatty acids ranging from C8 to C18 were reacted with recombinant human TNF. Modification with esters of C8 to C14 acids occurred as determined by consumption of positively charged amino groups monitored by native polyacrylamide gel electrophoresis; however, esters of longer chain lengths (C16, C18) were much less capable of introducing these chains via amide linkages, and thus these adducts were not further characterized. Biological assays revealed that retention of activity was inversely dependent both on the number of chains introduced and on their length; activity was most conserved (greater than 50%) in a TNF preparation modified with only approximately 1-2.5 caprylic acid (C8) residues/trimer. This preparation was found to bind with high efficiency (approximately 50%) to preformed dipalmitoylphosphatidylcholine-small unilamellar vesicles. The extent of binding closely paralleled both the number of chains introduced and their length; binding was even more efficient (80-90%) for TNF modified either with approximately 3.5 caprylic acid residues/trimer or with approximately 1.5 residues of myristic acid (C14). However, the biological activity of these acylated TNFs was further reduced by this more extensive chemical modification (less than 50% activity for C8 and less than 10% for C14). The biological activity of dipalmitoylphosphatidylcholine-small unilamellar vesicle-C8-TNF was found to be comparable to that of the nonliposomal C8-TNF. Thus, biologically active preparations of liposomal-lipophilic TNF can be prepared with high efficiency.

1,2-Dipalmitoylphosphatidylcholine↗

[Demonstration of glycoprotein antigens associated with stomach tumors].

After precipitation of the glycoproteins from gastric tumor tissues by caprylic acid, immunochemical methods were applied to the research of specific gastric tumor antigens; this precipitation process by caprylic acid was less aggressive than the use of urea or proteases. The purification of a fraction associated with tumor tissue has been carried out by affinity chromatography with a specific antiserum immobilized on Sepharose. The obtained fraction contains 4 proteic antigens. One of them is common with all the gastric extracts. Neither CEA, nor alpha-foetoprotein has been detected in this fraction. The corresponding antiserum seems to show a tumor specificity, whereas tissue specificity has to be demonstrated.

Antigens, Neoplasm↗

STRUCTURAL CHANGES IN ISOLATED LIVER MITOCHONDRIA OF RATS DURING ESSENTIAL FATTY ACID DEFICIENCY.

Liver mitochondria isolated in 0.44 M sucrose from rats deficient in essential fatty acids (EFA) oxidized citrate, succinate, alpha-ketoglutarate, glutamate, and pyruvate at a faster rate than did mitochondria isolated from normal rats; however, the oxidation of malate, caprylate, and beta-hydroxybutyrate was not significantly increased. The mitochondria from deficient rats exhibited an increased ATPase activity and extensive structural damage as revealed by electron microscope examination of thin sections. An increase in citrate oxidation and ATPase activity, together with some structural damage, could be demonstrated as early as the 4(th) week in rats on a fat-free diet. Saturated fat in the diet did not prevent the change in mitochondrial structure but accelerated its appearance. Both the biochemical and structural defects could be reversed within three weeks after feeding deficient rats a source of EFA. In the presence of a phosphate acceptor the effect of EFA deficiency on substrate oxidation was largely eliminated. A trend toward a reduced efficiency of oxidative phosphorylation was noted in mitochondria from EFA-deficient rats, but significant uncoupling was found only in the case of citrate, beta-hydroxybutyrate, and glutamate in the presence of malonate. Together with the increased ATPase activity, the uncoupling of phosphorylation could account for the poor respiratory control found with the deficient preparation. However, EFA deficiency was without effect on the respiration of liver slices, which supports the belief that the observed changes in oxidation and phosphorylation are an artifact resulting from damage sustained by the deficient mitochondria during their isolation.

Adenosine Triphosphatases↗