Evaluating hydrogen bonding control in the diastereoselective Diels-Alder reactions of 9-(2-aminoethyl)-anthracene derivatives.

Several 9-(2-aminoethyl)anthracene derivatives were prepared with different nitrogen substitutents including alkyl, acetamide, trifluoroacaeamide and t-butyl carbamate. The selectivity in Diels-Alder cyclodaddition reaction with N-methyl maleimide was evaluated through single crystal X-ray analysis of the products. Models for the change in selectivity with hydrogen bond acceptor are proposed, supported by DFT level calculations.

Aminoglycoside- and glycopeptide-induced ototoxicity in children: a systematic review.

BACKGROUND: Ototoxicity has been reported after administration of aminoglycosides and glycopeptides. OBJECTIVES: To identify available evidence for the occurrence and determinants of aminoglycoside- and glycopeptide-related ototoxicity in children. MATERIALS AND METHODS: Systematic electronic literature searches that combined ototoxicity (hearing loss, tinnitus and/or vertigo) with intravenous aminoglycoside and/or glycopeptide administration in children were performed in PubMed, EMBASE and Cochrane Library databases. Studies with sample sizes of ≥50 children were included. The QUIPS tool and Cochrane criteria were used to assess the quality and risk of bias of included studies. RESULTS: Twenty-nine aminoglycoside-ototoxicity studies met the selection criteria (including 7 randomized controlled trials). Overall study quality was medium/low. The frequency of hearing loss within these studies ranged from 0%-57%, whereas the frequency of tinnitus and vertigo ranged between 0%-53% and 0%-79%, respectively. Two studies met the criteria on glycopeptide-induced ototoxicity and reported hearing loss frequencies of 54% and 55%. Hearing loss frequencies were higher in gentamicin-treated children compared to those treated with other aminoglycosides. In available studies aminoglycosides had most often been administered concomitantly with platinum agents, diuretics and other co-medication. CONCLUSIONS: In children the reported occurrence of aminoglycoside/glycopeptide ototoxicity highly varies and seems to depend on the diagnosis, aminoglycoside subtype and use of co-administered medication. More research is needed to investigate the prevalence and determinants of aminoglycoside/glycopeptide ototoxicity. Our results indicate that age-dependent audiological examination may be considered for children frequently treated with aminoglycosides/glycopeptides especially if combined with other ototoxic medication.

TCERG1L allelic variation is associated with cisplatin-induced hearing loss in childhood cancer, a PanCareLIFE study.

In children with cancer, the heterogeneity in ototoxicity occurrence after similar treatment suggests a role for genetic susceptibility. Using a genome-wide association study (GWAS) approach, we identified a genetic variant in TCERG1L (rs893507) to be associated with hearing loss in 390 non-cranial irradiated, cisplatin-treated children with cancer. These results were replicated in two independent, similarly treated cohorts (n = 192 and 188, respectively) (combined cohort: P = 5.3 × 10-10, OR 3.11, 95% CI 2.2-4.5). Modulating TCERG1L expression in cultured human cells revealed significantly altered cellular responses to cisplatin-induced cytokine secretion and toxicity. These results contribute to insights into the genetic and pathophysiological basis of cisplatin-induced ototoxicity.

Short-term manipulation of plasma free fatty acids does not change skeletal muscle concentrations of ceramide and glucosylceramide in lean and overweight subjects.

CONTEXT: Increased plasma free fatty acid (FFA) concentrations may be in part responsible for the increased levels of ceramide in skeletal muscle of obese subjects. OBJECTIVE: We studied the effect of lowering and increasing plasma FFA levels on muscle ceramide and glucosylceramide concentrations in lean and obese subjects. DESIGN: Plasma FFAs were either increased or decreased for 6 h by infusing a lipid emulsion or using Acipimox, respectively. Muscle biopsies were performed before and after the intervention for measurements of ceramide and glucosylceramide. STUDY SUBJECTS: Eight lean [body mass index 21.9 (range, 19.6-24.6) kg/m2] and six overweight/obese [body mass index 34.4 (27.8-42.5) kg/m2] subjects without type 2 diabetes mellitus participated in the study. MAIN OUTCOME MEASURE: Differences in muscle ceramide and glucosylceramide upon manipulation of plasma FFAs were measured. RESULTS: There were no differences in muscle ceramide and glucosylceramide between lean and obese subjects, respectively. Increasing or decreasing plasma FFAs for 6 h had no effect on ceramide [high FFAs: 24 (19-25) vs. 24 (22-27) pmol/mg muscle, P=0.46; and 22 (20-28) vs. 24 (18-26) pmol/mg muscle, P=0.89 in lean and obese, respectively; low FFAs: 26 (24-35) vs. 23 (18-27) pmol/mg muscle, P=0.17 and 24 (15-44) vs. 24 (19-42) pmol/mg muscle, P=0.6 in lean and obese, respectively] and glucosylceramide [high FFAs: 2.0 (1.7-4.3) vs. 3.4 (2.1-4.6) pmol/mg muscle, P=0.17; and 3.0 (1.3-6.7) vs. 2.6 (1.2-3.9) pmol/mg muscle, P=0.89 in lean and obese, respectively; low FFAs: 2.2 (1.0-4.4) vs. 1.7 (1.4-3.0) pmol/mg muscle, P=0.92; and 6.6 (1.0-25.0) vs. 4.3 (1.3-7.6) pmol/mg muscle, P=0.7 in lean and obese, respectively] concentrations in skeletal muscle. CONCLUSION: Short-term manipulation of plasma FFAs has no effect on ceramide and glucosylceramide concentrations in skeletal muscle from lean and obese subjects.

Autophagy and signaling: their role in cell survival and cell death.

Macroautophagy is a vacuolar, self-digesting mechanism responsible for the removal of long-lived proteins and damaged organelles by the lysosome. The discovery of the ATG genes has provided key information about the formation of the autophagosome, and about the role of macroautophagy in allowing cells to survive during nutrient depletion and/or in the absence of growth factors. Two connected signaling pathways encompassing class-I phosphatidylinositol 3-kinase and (mammalian) target of rapamycin play a central role in controlling macroautophagy in response to starvation. However, a considerable body of literature reports that macroautophagy is also a cell death mechanism that can occur either in the absence of detectable signs of apoptosis (via autophagic cell death) or concomitantly with apoptosis. Macroautophagy is activated by signaling pathways that also control apoptosis. The aim of this review is to discuss the signaling pathways that control macroautophagy during cell survival and cell death.

Transfer of reducing equivalents across the mitochondrial membrane. I. Hydrogen transfer mechanisms involved in the reduction of pyruvate to lactate in isolated liver cells.

(1) The reduction of pyruvate to lactate has been studied in isolated liver cells in order to elucidate the mechanims involved in the transfer of reducing equivalents from mitochondria to cytosol. (2) Manipulation of the cytosolic oxaloacetate concentration did not support the malate-oxaloacetate cycle as being responsible for the transfer of reducing equivalents out of the mitochondria: (a) With pyruvate plus oleate present 2 mM Amytal caused a 10-fold decrease in the oxaloacetate concentration, but had only a small inhibitory effect on lactate production. Oleate was essential in order to prevent disintegration of the cells in the presence of Amytal. (b) Quinolinate, an inhibitor of phosphoenolpyruvate carboxylase (GTP: oxaloacetate carboxylyase, transphosphorylating, EC 4.1.1.32), caused a several-fold increase in the oxaloacetate concentration but inhibited lactate production from pyruvate; this was accompanied by an increased reduction of mitochondrial pyridine nucleotides. (3) p-Chlorophenyl pyruvate, an inhibitor of pyruvate carboxylase (pyruvate: carbondioxide ligase, ADP, EC 6.4.1.1), also inhibited lactate production from pyruvate. (4) It is postulated that with pyruvate as substrate, recycling of carbon via pyruvate carboxylase, phosphoenolpyruvate carboxylase and pyruvate kinase (ATP: pyruvate phosphotransferase, EC 2.7.1.40) is an important, energy-requiring, mechanism for the transfer of the proportion of NADH not directly associated with gluconeogenesis.

Turnover of N-acetylglutamate in isolated rat hepatocytes.

Isolated hepatocytes from starved rats were loaded with N-[14C]acetylglutamate by preincubating them with [14C]bicarbonate, oleate, NH3, ornithine and lactate. Turnover of N-acetylglutamate in these cells was subsequently measured in an unlabelled medium under conditions of minimal flux (oleate alone present) and maximal flux (oleate, NH3, ornithine and lactate present) through the urea cycle. 1. Direct measurement of the distribution of N-[14C]acetylglutamate across the mitochondrial membrane in the hepatocytes showed that, under the conditions studied, the rate of degradation of total intracellular N-[14C]acetylglutamate was about equal to the rate of efflux of N-acetylglutamate from the mitochondria. 2. In the presence of oleate alone, intramitochondrial N-acetylglutamate decreased because mitochondrial N-acetylglutamate efflux predominated over the synthesis of N-acetylglutamate in the mitochondria. 3. In the presence of oleate, NH3, ornithine and lactate both the rate of synthesis of N-acetylglutamate and the rate of its transport out of the mitochondria were increased when compared with the condition with oleate alone. However, the intramitochondrial concentration of N-acetylglutamate increased because initially the rate of its synthesis exceeded that of its efflux from the mitochondria. Finally, a steady state was reached in which both rates were equal. 4. The data indicate that in hepatocytes from starved rats N-acetylglutamate transport out of the mitochondria takes place at a rate proportional to its intramitochondrial concentration. It is concluded that transport of N-acetylglutamate either occurs by diffusion or is mediated by a transport system with a high Km for intramitochondrial N-acetylglutamate.

Relationship between intramitochondrial citrate and the activity of carbamoyl-phosphate synthase (ammonia).

The possibility of control of the activity of carbamoyl-phosphate synthase (ammonia) (EC 2.7.2.5) in rat-liver mitochondria by variation in the intramitochondrial free Mg2+ concentration has been investigated. Carbamoyl-phosphate synthase activity was measured by coupling the formation of carbamoylphosphate to the synthesis of citrulline in a reaction mixture containing ammonia, bicarbonate, a source of ATP, and ornithine. The synthesis of citrulline was inhibited by lowering the concentration of intramitochondrial free Mg2+. This could be achieved not only by depleting the mitochondria of Mg2+ (by adding the ionophore A23187), but also by increasing the intramitochondrial concentration of citrate. Under various conditions an inverse relationship between the rate of citrulline synthesis and the magnitude of the intramitochondrial concentration of citrate was observed. Inhibition of citrulline synthesis by intramitochondrial citrate could be partly reversed by addition of Mg2+ in the presence of A23187. Possible implications of the regulation of carbamoyl-phosphate synthase (ammonia) activity by intramitochondrial citrate for nitrogen metabolism in the liver are discussed.

Arginine uptake by isolated rat liver mitochondria.

The question of arginine uptake by mitochondria is important in that arginine is an allosteric effector of N-acetylglutamate synthetase. Thus, changes in mitochondrial arginine concentration have the potential for acutely modifying levels of N-acetylglutamate, a compound necessary for maximal activity of carbamyl phosphate synthesis. Mitochondria were isolated from chow-fed rats, incubated with [guanido-14C]arginine and were centrifuged through silicon oil into perchloric acid for determination of intramitochondrial metabolites. Arginine was separated from urea by cation-exchange resin. Mitochondrial water space was determined by [14C]urea arising from arginase activity associated with the mitochondrial preparations. Extramatrix space was determined by parallel incubations with [inulin-14C]carboxylic acid or [14C]sucrose. There was considerable degradation of arginine by arginase associated with the mitochondrial preparation. This was inhibited by 7 mM ornithine and 7 mM lysine. Arginine was concentrated intramitochondrially to 4-times the extramitochondrial levels. The concentration ratio was decreased in the presence of ornithine and lysine but not with citrulline, NH4Cl, glutamate, glutamate or leucine. No uptake was observed when mitochondria were incubated at 0 degree C. Mitochondria did not concentrate citrulline.

Effect of trifluoperazine on the stimulation by Ca2+-dependent hormones of gluconeogenesis from glutamine in isolated hepatocytes.

In continuation of our previous studies we have investigated some aspects of the hormonal control of glutamine metabolism in isolated rat hepatocytes. (1)Catecholamines, angiotensin II and vasopressin stimulate gluconeogenesis from glutamine more than 2-fold. These effects require the presence of Ca2+ in the incubation medium. (2) The phenothiazine, trifluoperazine, a purported specific inhibitor of calmodulin, completely blocks the stimulation by catecholamines without affecting the response to the other two hormones. (3) The effectiveness of trifluoperazine in preventing the stimulation of gluconeogenesis by catecholamines was dependent on the concentrations of both the hormones and the inhibitor. (4) Trifluoperazine, at concentrations that prevent stimulation by epinephrine of gluconeogenesis, was as effective as phentolamine in blocking the binding of [3H]epinephrine to intact hepatocytes. (5) These studies support the view (Blackmore, P.F., El-Refai, M.F., Dehaye, J.-P., Strickland, W.G., Haghes, B.P. and Exton, J.H. (1981) FEBS Lett. 123, 245--248) that inhibition by trifluoperazine of alpha-adrenergic stimuli does not necessarily mean that calmodulin is involved in post-receptor events.

Phthalonic acid, an inhibitor of alpha-oxoglutarate transport in mitochondria.

Phthalonic acid is a powerful inhibitor of alpha-oxoglutarate transport in mitochondria. This conclusion is based on the following observations: 1. Phthalonic acid inhibits the oxidation of alpha-oxoglutarate but has no effect on the oxidation of glutamate or cis-aconitate. 2. With arsenite present, phthalonic acid inhibits the oxidation of glutamate plus malate and of cis-aconitate plus malate. Under these conditions alpha-oxoglutarate accumulates inside the mitochondria. With glutamate plus malate as substrates the inhibition is competitive with malate with a Ki value of 20 muM. 3. Phthalonic acid inhibits the oxidation of intramitochondrial NAD(P)H by alpha-oxoglutarate plus ammonia. The inhibition is competitive with respect to alpha-oxoglutarate with a Ki of 30 muM. 4. Phthalonic acid inhibits the exchange between extramitochondrial alpha-oxoglutarate and intramitochondrial malate.

Cell swelling and glycogen metabolism in hepatocytes from fasted rats.

Cell swelling is known to increase net glycogen production from glucose in hepatocytes from fasted rats by activating glycogen synthase. Since both active glycogen synthase and phosphorylase are present in hepatocytes, suppression of flux through phosphorylase may also contribute to the net increase in glycogen synthesis by cell swelling. We have developed an isotopic procedure to estimate the fluxes through glycogen synthase and phosphorylase in intact hepatocytes and we have examined the effect of cell swelling on both enzyme fluxes. The following observations were made. (1) Hypotonic or glutamine-induced cell swelling increased net glycogen production by activating flux through glycogen synthase with little effect on phosphorylase flux. Proline, previously shown to increase glycogen synthesis more than could be accounted for by its ability to cause cell swelling, increased flux through glycogen synthase and inhibited phosphorylase flux. (2) Incorporation of [14C]glucose into glycogen preceded complete mixing of [14C]glucose with the intracellular pool of UDPglucose. It is concluded that cell swelling affects glycogen synthase only and that UDPglucose is compartmentalized.

Dose intensity of MOPP chemotherapy and survival in Hodgkin's disease.

The association between dose intensity of chemotherapy with the rate of complete remission (CR), the duration of disease-free survival (DFS), and overall survival (OS) was separately analyzed for 67 patients initially treated with mechlorethamine, vincristine, procarbazine, and prednisone (MOPP), and for 75 patients in relapse following radiotherapy who had received MOPP as a salvage regimen. In both groups of patients, the fraction of the total dose of mechlorethamine delivered in all cycles divided by the planned dose for six cycles was strongly associated with OS (P = .002 for patients receiving initial MOPP and P = .02 for the salvage group, respectively). B symptoms were independent of drug-derived variables associated with OS (corresponding P values .03 for initial MOPP and .004 for the salvage group). The predictive value of mechlorethamine dosage with regard to OS was retained in an analysis restricted to the patients receiving greater than or equal to six cycles of chemotherapy. In the initial chemotherapy group, mechlorethamine dosage was associated with attainment of CR but none of the variables tested was predictive of DFS. In the salvage chemotherapy group, mechlorethamine dosage was associated with attainment of CR and duration of DFS as well. The results emphasize that, besides tumor characteristics, optimal dosage of chemotherapy is of great importance for survival.

Acute inhibition of glucose-6-phosphate translocator activity leads to increased de novo lipogenesis and development of hepatic steatosis without affecting VLDL production in rats.

Glucose-6-phosphatase (G6Pase) is a key enzyme in hepatic glucose metabolism. Altered G6Pase activity in glycogen storage disease and diabetic states is associated with disturbances in lipid metabolism. We studied the effects of acute inhibition of G6Pase activity on hepatic lipid metabolism in nonanesthetized rats. Rats were infused with an inhibitor of the glucose-6-phosphate (G6P) translocator (S4048, 30 mg. kg(-1). h(-1)) for 8 h. Simultaneously, [1-(13)C]acetate was administered for determination of de novo lipogenesis and fractional cholesterol synthesis rates by mass isotopomer distribution analysis. In a separate group of rats, Triton WR 1339 was injected for determination of hepatic VLDL-triglyceride production. S4048 infusion significantly decreased plasma glucose (-11%) and insulin (-48%) levels and increased hepatic G6P (201%) and glycogen (182%) contents. Hepatic triglyceride contents increased from 5.8 +/- 1.4 micromol/g liver in controls to 20.6 +/- 5.5 micromol/g liver in S4048-treated animals. De novo lipogenesis was increased >10-fold in S4048-treated rats, without changes in cholesterol synthesis rates. Hepatic mRNA levels of acetyl-CoA carboxylase and fatty acid synthase were markedly induced. Plasma triglyceride levels increased fourfold, but no differences in plasma cholesterol levels were seen. Surprisingly, hepatic VLDL-triglyceride secretion was not increased in S4048-treated rats. These studies demonstrate that inhibition of the G6Pase system leads to acute stimulation of fat synthesis and development of hepatic steatosis, without affecting hepatic cholesterol synthesis and VLDL secretion. The results emphasize the strong interactions that exist between hepatic carbohydrate and fat metabolism.

Turnover of peroxisomal vesicles by autophagic proteolysis in cultured fibroblasts from Zellweger patients.

Previous studies have shown that in fibroblasts from patients with the Zellweger syndrome (ZS) aberrant membrane structures are present which contain peroxisomal membrane proteins (Santos, M. J. et al., Science 239, 1536-1538 (1988)). In order to characterize these structures we have performed double labeling immunoelectron microscopy experiments using antisera directed against the 69 kDa peroxisomal integral membrane protein (PMP) and lysosomal hydrolases. The results indicate that at least 80% of the structures earlier referred to as 'peroxisomal ghosts' contain lysosomal hydrolases. In addition, we have studied the effect of culture of ZS fibroblasts in the presence of 3-methyladenine, an inhibitor of autophagy, on the intracellular distribution of the 69 kDa PMP. Immunofluorescence experiments showed that in the presence of 3-methyladenine there is an increase in fluorescent spots and a change in the distribution of the spots from mainly perinuclear to randomly distributed throughout the cytoplasm. Double labeling immunoelectron microscopy revealed that after culture in the presence of 3-methyladenine the 69 kDa PMP also accumulates mainly in compartments containing lysosomal hydrolases. In one ZS cell line we found that after culture in the presence of 3-methyladenine there was also an accumulation of structures which were as small as normal microperoxisomes. We conclude that in ZS fibroblasts the 69 kDa PMP is mainly present in lysosomal compartments, presumably degradative autophagic vacuoles. Furthermore, in ZS fibroblasts peroxisomes of apparently normal morphology may be synthesized, but they are degraded by autophagic proteolysis.

Dietary carbohydrate deprivation increases 24-hour nitrogen excretion without affecting postabsorptive hepatic or whole body protein metabolism in healthy men.

Because insulin is an important regulator of protein metabolism, we hypothesized that physiological modulation of insulin secretion, by means of extreme variations in dietary carbohydrate content, affects postabsorptive protein metabolism. Therefore, we studied the effects of three isocaloric diets with identical protein content and low-carbohydrate/high-fat (2% and 83% of total energy, respectively), intermediate-carbohydrate/intermediate-fat (44% and 41% of total energy, respectively), and high-carbohydrate/low-fat (85% and 0% of total energy, respectively) content in six healthy men. Whole body protein metabolism was assessed by 24-h urinary nitrogen excretion, postabsorptive leucine kinetics, and fibrinogen and albumin synthesis by infusion of [1-(13)C]leucine and [1-(13)C]valine. The low-carbohydrate/high-fat diet resulted in lower absorptive and postabsorptive plasma insulin concentrations, and higher rates of nitrogen excretion compared with the other two diets: 15.3 +/- 0.9 vs. 12.1 +/- 1.1 (P = 0.03) and 10.8 +/- 0.5 g/24 h (P = 0.005), respectively. Postabsorptive rates of appearance of leucine and of leucine oxidation were not different among the three diets. In addition, dietary carbohydrate content did not affect the synthesis rates of fibrinogen and albumin. In conclusion, eucaloric carbohydrate deprivation increases 24-h nitrogen loss but does not affect postabsorptive protein metabolism at the hepatic and whole body level. By deduction, dietary carbohydrate is required for an optimal regulation of absorptive, rather than postabsorptive, protein metabolism.

The effects of carbohydrate variation in isocaloric diets on glycogenolysis and gluconeogenesis in healthy men.

To evaluate the effect of dietary carbohydrate content on postabsorptive glucose metabolism, we quantified gluconeogenesis and glycogenolysis after 11 days of high carbohydrate (85% carbohydrate), control (44% carbohydrate), and very low carbohydrate (2% carbohydrate) diets in six healthy men. Diets were eucaloric and provided 15% of energy as protein. Postabsorptive glucose production was measured by infusion of [6,6-2H2]glucose, and fractional gluconeogenesis was measured by ingestion of 2H2O. Postabsorptive glucose production rates were 13.0 +/- 0.7, 11.4 +/- 0.4, and 9.7 +/- 0.4 micromol/kg x min after high carbohydrate, control, and very low carbohydrate diets, respectively (P < 0.001 among the three diets). Gluconeogenesis was about 14% higher after the very low carbohydrate diet (6.3 +/- 0.2 micromol/kg x min; P = 0.001) compared to the control diet, but was not different between the high carbohydrate and control diets (5.5 +/- 0.3 vs. 5.5 +/- 0.2 micromol/kg x min). The rates of glycogenolysis were 7.5 +/- 0.5, 5.9 +/- 0.3, and 3.4 +/- 0.3 micromol/kg x min, respectively (P < 0.001 among the three diets). We conclude that under eucaloric conditions in healthy subjects, dietary carbohydrate content affects the rate of postabsorptive glucose production mainly by modulation of glycogenolysis. In contrast, dietary carbohydrate content affects the postabsorptive rate of gluconeogenesis minimally, as evidenced by only a slight increase in gluconeogenesis during severe carbohydrate restriction.

Channeling of ammonia from glutaminase to carbamoyl-phosphate synthetase in liver mitochondria.

In isolated rat-liver mitochondria the rate of citrulline synthesis from glutamine does not respond to changes in the ammonia concentration in the extramitochondrial fluid. This suggest that ammonia, produced in the mitochondria via glutaminase, is directly channeled to carbamoyl-phosphate synthetase.

Hepatocyte swelling increases inositol 1,4,5-trisphosphate, calcium and cyclic AMP concentration but antagonizes phosphorylase activation by Ca2(+)-dependent hormones.

Swelling of hepatocytes increases the concentration of inositol 1,4,5-trisphosphate, Ca2+ and cAMP, without activating glycogen phosphorylase. In these hepatocytes, the activation of phosphorylase by suboptimal concentrations of vasopressin or angiotensin II was partly antagonized.

Autophagic degradation of peroxisomes in isolated rat hepatocytes.

Degradation of the peroxisomal enzymes fatty acyl-CoA oxidase and catalase was studied in hepatocytes isolated from rats treated with clofibrate and from control rats. Hepatocytes were incubated in the absence of amino acids in order to ensure maximal flux through the autophagic pathway and in the presence of cycloheximide to inhibit protein synthesis. (1) Degradation of the two peroxisomal enzymes in hepatocytes from clofibrate-fed rats, but not in hepatocytes from control rats, was much faster than that of other intracellular enzymes. This increased degradation of the peroxisomal enzymes was almost completely prevented by 3-methyladenine, an inhibitor of macroautophagic sequestration. (2) The increased degradation of the peroxisomal enzymes was also inhibited by a long-chain (C16:0) and a very-long-chain (C26:0) fatty acid, but not by C12:0, a medium-chain fatty acid, or by C8:0, a short-chain fatty acid. These results provide direct evidence for the proposal that autophagic sequestration can be highly selective [(1987) Exp. Mol. Pathol. 46, 114-122]. It is concluded that preferential autophagy of peroxisomes is prevented when these organelles are supplied with their fatty acid substrates.