Ferrous sulfate efficiently kills Vibrio parahaemolyticus and protects salmon sashimi from its contamination.

The primary seafood-borne pathogen Vibrio parahaemolyticus seriously threats the health of consumers preferring raw-fish products, becoming a global concern in food safety. In the present study, we found ferrous sulfate (FeSO4), a nutritional iron supplement, could efficiently induce the death of V. parahaemolyticus. Further, the bactericidal mechanisms of FeSO4 were explored. With a fluorescent probe of Fe2+, a significant influx of Fe2+ was determined in V. parahaemolyticus exposed to FeSO4, and the addition of an intracellular Fe2+ chelator was able to block the cell death. This suggested that cell death in V. parahaemolyticus induced by FeSO4 was dependent on the influx of Fe2+. It was intriguing that we did not observe the eruption of reactive oxygen species (ROS) and lipid hydroperoxides by Fe2+, but the application of liproxstatin-1 (a ferroptosis inhibitor) significantly modified the occurrence of cell death in V. parahaemolyticus. These results suggested FeSO4-induced cell death in V. parahaemolyticus be a ferroptosis differing from that in mammalian cells. Through transcriptome analysis, it was discovered that the exposure of FeSO4 disturbed considerable amounts of gene expression in V. parahaemolyticus including those involved in protein metabolism, amide biosynthesis, two-component system, amino acid degradation, carbon metabolism, citrate cycle, pyruvate metabolism, oxidative phosphorylation, and so on. These data suggested that FeSO4 was a pleiotropic antimicrobial agent against V. parahaemolyticus. Notably, FeSO4 was able to eliminate V. parahaemolyticus in salmon sashimi as well, without affecting the color, texture, shearing force, and sensory characteristics of salmon sashimi. Taken together, our results deciphered a unique ferroptosis in V. parahaemolyticus by FeSO4, and highlighted its potential in raw-fish products to control V. parahaemolyticus.

Kinetics of ventilation-induced changes in diaphragmatic metabolism by bilateral phrenic pacing in a piglet model.

Perioperative necessity of deep sedation is inevitably associated with diaphragmatic inactivation. This study investigated 1) the feasibility of a new phrenic nerve stimulation method allowing early diaphragmatic activation even in deep sedation and, 2) metabolic changes within the diaphragm during mechanical ventilation compared to artificial activity. 12 piglets were separated into 2 groups. One group was mechanically ventilated for 12 hrs (CMV) and in the second group both phrenic nerves were stimulated via pacer wires inserted near the phrenic nerves to mimic spontaneous breathing (STIM). Lactate, pyruvate and glucose levels were measured continuously using microdialysis. Oxygen delivery and blood gases were measured during both conditions. Diaphragmatic stimulation generated sufficient tidal volumes in all STIM animals. Diaphragm lactate release increased in CMV transiently whereas in STIM lactate dropped during this same time point (2.6 vs. 0.9 mmol L-1 after 5:20 hrs; p < 0.001). CMV increased diaphragmatic pyruvate (40 vs. 146 µmol L-1 after 5:20 hrs between CMV and STIM; p < 0.0001), but not the lactate/pyruvate ratio. Diaphragmatic stimulation via regular electrodes is feasible to generate sufficient ventilation, even in deep sedation. Mechanical ventilation alters the metabolic state of the diaphragm, which might be one pathophysiologic origin of ventilator-induced diaphragmatic dysfunction. Occurrence of hypoxia was unlikely.

Hypertonic saline dextran improves outcome after hypothermic circulatory arrest: a study in a surviving porcine model.

BACKGROUND: Hypertonic saline dextran (HSD) has been shown to have neuroprotective properties. In the present study we have assessed its potential neuroprotective efficacy in the setting of hypothermic circulatory arrest in a surviving porcine model. METHODS: Twenty-four pigs were randomized to receive two 5-minute intravenous infusions (4 mL/kg) of either HSD (7.5 % saline, 6% dextran 70) or normal saline immediately after and 4 hours after a 75-minute period of hypothermic circulatory arrest at a brain temperature of 18 degrees C. RESULTS: The 7-day survival was 75% in the HSD group and 66% in the control group (p > 0.9). Brain total histopathologic score was lower in the HSD group (p = 0.01). Postoperative behavioral scores were higher in the HSD group on the second day after surgery (p = 0.03). Intracranial pressure was lower in the HSD group from 45 minutes to 8 hours after hypothermic circulatory arrest (p = 0.03). Cerebral perfusion pressure was higher in the HSD group from 45 minutes to 3 hours after hypothermic circulatory arrest (p = 0.06). Brain lactate concentration was lower in the HSD group when compared with controls (p = 0.05). Furthermore, brain glucose levels tended to be higher and brain lactate-pyruvate ratio and lactate-glucose ratio were lower in the HSD group. Brain tissue oxygen partial pressures were somewhat higher in the HSD group (p = 0.08). CONCLUSIONS: The use of HSD in experimental hypothermic circulatory arrest is associated with significantly better neurologic recovery, better histopathology, lower intracranial pressure, higher cerebral perfusion pressure, and better preservation of brain metabolism.

Effects of epinephrine and norepinephrine on hemodynamics, oxidative metabolism, and organ energetics in endotoxemic rats.

OBJECTIVE: To determine whether epinephrine increases lactate concentration in sepsis through hypoxia or through a particular thermogenic or metabolic pathway. DESIGN: Prospective, controlled experimental study in rats. SETTING: Experimental laboratory in a university teaching hospital. INTERVENTIONS: Three groups of anesthetized, mechanically ventilated male Wistar rats received an intravenous infusion of 15 mg/kg Escherichia coli O127:B8 endotoxin. Rats were treated after 90 min by epinephrine ( n=14), norepinephrine ( n=14), or hydroxyethyl starch ( n=14). Three groups of six rats served as time-matched control groups and received saline, epinephrine, or norepinephrine from 90 to 180 degrees min. Mean arterial pressure, aortic, renal, mesenteric and femoral blood flow, arterial blood gases, lactate, pyruvate, and nitrate were measured at baseline and 90 and 180 min after endotoxin challenge. At the end of experiments biopsy samples were taken from the liver, heart, muscle, kidney, and small intestine for tissue adenine nucleotide and lactate/pyruvate measurements. MEASUREMENTS AND RESULTS: Endotoxin induced a decrease in mean arterial pressure and in aortic, mesenteric, and renal blood flow. Plasmatic and tissue lactate increased with a high lactate/pyruvate (L/P) ratio. ATP decreased in liver, kidney, and heart. The ATP/ADP ratio did not change, and phosphocreatinine decreased in all organs. Epinephrine and norepinephrine increased mean arterial pressure to baseline values. Epinephrine increased aortic blood flow while renal blood low decreased with both drugs. Plasmatic lactate increased with a stable L/P ratio with epinephrine and did not change with norepinephrine compared to endotoxin values. Nevertheless epinephrine and norepinephrine when compared to endotoxin values did not change tissue L/P ratios or ATP concentration in muscle, heart, gut, or liver. In kidney both drugs decreased ATP concentration. CONCLUSIONS: Our data demonstrate in a rat model of endotoxemia that epinephrine-induced hyperlactatemia is not related to cellular hypoxia.

Quality changes of onion (Allium cepa L.) as affected by the drying process.

Thin layer drying experiments of sliced onion were carried out under different controlled conditions using a laboratory dryer. Quality changes of the dried product were evaluated by analysis of colour, pyruvate, chemical and sensory parameters. The results obtained proved that drying temperatures above 65 degrees C exert a pronounced influence on colour changes. The pyruvate content decreased with increasing of temperature and slice thickness. The sugar content was also found to be significantly influenced by the drying temperature. The rate of ascorbic acid degradation decreased with increasing temperature and slice thickness. Significant correlations were obtained between chemically determined pyruvate content and sensory evaluated odour of the dried onion.

Trypanosoma evansi: measurement of pyruvate production as an indicator of the drug sensitivity of isolates in vitro.

In a previous study, three in vitro methods for the assessment of drug sensitivity among Trypanosoma evansi isolates were compared--a direct counting method, pyruvate production method and uptake of radiolabelled hypoxanthine. The pyruvate assay system, which measures the amount of pyruvate in the supernatant of growing populations of trypanosomes by a spectrophotometric method, was selected for further investigation with regard to its suitability for field studies. The effect of initial seeding density and incubation time on the growth of three stocks of T. evansi--TREU 1840 and TREU 1981 (suramin sensitive) and TREU 2136 (suramin resistant)--and drug sensitivities revealed by the pyruvate assay and direct counting were examined to optimise assay conditions. Maximum densities and pyruvate production achieved were not affected by varying the initial seeding densities in the range of 5 x 10(4)-5 x 10(5)/ml and had been reached after 48 hours incubation with one exception: Pyruvate levels continued to increase up to 72 hours in the suramin resistant stock. However, inhibition curves were affected by initial seeding density and incubation period. Results suggested that an initial seeding density of 1 x 10(5)/ml and an incubation time of 48 hours are optimal for the assay. Using these assay conditions, the isolates were screened against suramin, quinapyramine sulphate and Cymelarsan, the trypanocides used most commonly against T. evansi. This assay proved to be a relatively simple and cheap technique applicable to screening large numbers of isolates of differing sensitivities to trypanocidal drugs.

Effects of ethanol on urinary acidification and on gluconeogenesis by isolated renal tubules.

Class I alcohol dehydrogenase (ADH) is present in the kidney of rats. Rats fed an alcohol-containing diet long-term had higher urinary pH and reduced titratable acidity compared with pair-fed controls; rates of ammonium excretion were unchanged. The effects of ethanol on the metabolism of isolated renal tubules were then studied. Gluconeogenesis from lactate, pyruvate, or glutamine was not inhibited by 10 mmol/L ethanol during 30- or 60-minute incubations, although there was a trend toward increased lactate/pyruvate ratios at 30 minutes in the presence of ethanol. When the medium was also supplemented with oleate, glucose synthesis from most substrates was decreased, and the addition of ethanol inhibited glucose synthesis dramatically. This interaction between oleate and ethanol was not abolished by 4-methylpyrazole, an inhibitor of ADH. This effect of ethanol was highly dependent on the concentration of oleate present in the medium and was not observed with palmitate or decanoate; the inhibition was reversed by increasing the medium concentration of albumin. We conclude that ethanol may mildly perturb the redox state of isolated kidney tubules without inhibiting glucose synthesis, and that ethanol and oleate interact to inhibit renal gluconeogenesis by a mechanism highly dependent on the fatty acid concentration. The mechanism by which ethanol in the diet reduces renal acid excretion remains unknown.

Effect of L-carnitine on cerebral and hepatic energy metabolites in congenitally hyperammonemic sparse-fur mice and its role during benzoate therapy.

Sparse-fur (spf) mutant mice with X-linked ornithine transcarbamylase deficiency were used to study the effect of L-carnitine on energy metabolites in congenital hyperammonemia. L-Carnitine was used at doses of 2, 4, 8, or 16 mmol/kg body weight (BW), and levels of ammonia, glutamine, glutamate, and some intermediates of energy metabolism were measured in brain and liver of spf/Y mice. Cerebral and hepatic levels of ammonia were decreased with 4 mmol L-carnitine (P < .001), whereas other doses did not seem to have any effect on this metabolite. Cerebral levels of glutamine were decreased following administration of L-carnitine at doses of up to 4 mmol/kg BW, whereas hepatic glutamine levels remained unaltered at all doses of L-carnitine. Both cerebral and hepatic levels of pyruvate, lactate, and alpha-ketoglutarate were decreased at doses of up to 8 mmol L-carnitine/kg BW. L-Carnitine treatment elevated adenosine triphosphate (ATP), free coenzyme A (CoA), and acetyl CoA levels in both brain and liver of spf/Y mice. Cytosolic and mitochondrial redox ratios of spf/Y mice, which were altered by congenital chronic hyperammonemia, were partially corrected by L-carnitine administration. L-Carnitine supplementation to spf/Y mice during sodium benzoate therapy also restored the availability of free CoA and ATP, thus counteracting the adverse effects of higher doses of sodium benzoate. These changes in free CoA and acetyl CoA levels could be due to the deinhibition of pantothenate kinase and stimulation of fatty acid oxidation by L-carnitine.(ABSTRACT TRUNCATED AT 250 WORDS)

Glycolytic changes after local hyperthermia in mouse liver and adenocarcinoma.

Glycolytic changes in an adenocarcinoma and in liver of C57B1 mice were determined for up to twelve hours after local hyperthermia at 43 degrees C for 30 min. The metabolites studied included glucose, glucose-6-phosphate, pyruvate, lactate, acetoacetate and beta-hydroxybutyrate. Both the glucose and glucose-6-phosphate levels decreased significantly in liver and tumour and remained low for up to twelve hours. The lactate levels increased slightly immediately after heating but were decreased at later times. However, the hepatic pyruvate levels decreased for up to two hours after heating but increased later reaching control levels. In both liver and tumour the levels of beta-hydroxybutyrate were significantly enhanced immediately after hyperthermia, whereas those of acetoacetate were lowered.

Vascular perfusion: a novel means of studying oviduct function.

An in situ preparation for the combined vascular and luminal perfusion of the rabbit oviduct has been developed. Medium 199, gassed with 5% CO2 in O2 and supplemented with heparin, antibiotics, and 2.5% wt/vol dialyzed bovine serum albumin was infused into the ovarian artery at a rate of 1 ml/min. Krebs Ringer bicarbonate medium was recirculated through the lumen at a rate of 50 microliter/min. The ovary was perfused together with the oviduct, and the preparation is viable for up to 3 h. Equal concentrations of pyruvate, lactate, glucose, and sucrose added to the vascular medium were transported at different rates into the lumen, as was a physiological mixture of amino acids. A proportion of the lactate entering the lumen was synthesized within the oviduct from vascular glucose. When glucose and pyruvate were omitted from the vascular medium, their appearance and that of lactate in the lumen was barely detectable, suggesting that these oviduct fluid components are mainly derived from the blood. The oviduct maintained a steady transmural potential difference of 5.9 mV (lumen negative). With vascular perfusion alone, oviduct fluid entered the oviduct lumen at a rate of 16.8 microliter/h. In oviducts taken from rabbits 3 days postovulation, there was a general decrease in the vascular to lumen flux of all nutrients measured. Preliminary work has shown that the preparation may be used to study ovulation, ovum pickup and transport, and fertilization.

Effect of an extract of Ginkgo biloba on rat brain energy metabolism in hypoxia.

The purpose of the present investigation was to determine brain energy metabolism under hypoxic conditions as influenced by an extract of Ginkgo biloba (EGB). Male Sprague-Dawley rats treated with EGB were exposed to hypobaric or hypoxic hypoxia, and at various time points during or after hypoxia the levels of high-energy phosphates and some substrates of glycolysis were measured in brain cortical tissue. Rats treated with EGB (100 mg/kg, intraperitoneally) survived hypobaric hypoxia for a much longer period than controls (e.g. controls: 3.9 +/- 1.8 min, EGB-treated: 23.6 +/- 10.5 min). The brain glucose level was elevated by EGB in most experimental series, and the lactate concentration was slightly lower than in control brains. The lowering of lactate/pyruvate ratio was due to the decreased level of lactate and to the enhanced concentration of pyruvate as well. When hypoxia was sufficiently severe the breakdown of high-energy phosphates was less pronounced in EGB-treated animals. After oral application of EGB for 14 days the rats survived hypobaric hypoxia for 25.7 +/- 2.5 min whereas controls survived for 11.5 +/- 5.1 min. However, brain energy metabolism was not significantly influenced by this oral treatment. It is suggested that changes in brain energy metabolism and blood flow may contribute to the protective effect of EGB against hypoxia.

A pyruvate-containing peptide of proline reductase in Clostridium sticklandii.

Proline reductase in Clostridium sticklandii is composed of 10 apparently identical subunits. Each subunit contains a pyruvate residue that became labeled when the cell culture was supplemented with [14C]serine. No NH2-terminal amino acid was detected either by dansylation, by Edman degradation, or by aminopeptidase M digestion. The results suggest that the NH2 terminus may be blocked by pyruvate. A pyruvate-containing peptide, also blocked at the NH2 terminus, was isolated from the NH2-terminal portion of proline reductase. From amino acid analysis the peptide was found to be rich in basic amino acids and to have a molecular weight of 4621. Its COOH-terminal amino acid was found to be serine and since the peptide was released from proline reductase by very mild alkali hydrolysis, it is suspected that an ester bond is involved.

Biochemical compartmentation of fish tissues. I. Brain energy reserves and its metabolic products.

The quantitative distribution of glycogen, lactate and pyruvate in the brain was studied in 4 regions of 9 fishes. The highest glycogen, lactate and pyruvate content was present in major carps followed by cat fishes and snake headed fishes. Glycogen and lactate contents were highest in the medulla oblongata while the highest pyruvate level was observed in the cerebellum. The observed differential distribution of glycogen, lactate and pyruvate in the different regions of the brain is discussed in relation to their functional differention and may depend on the nature of the diet, on the environment and growth rate, etc., of the fishes.

[Effect of short-term microcirculatory disorders on indices of myocardial energy metabolism]. / Vliianie kratkovremennogo narusheniia mikrotsirkuliatsii na pokazateli énergeticheskogo obmena v miokarde.

Disturbance of the microcirculation produced by the combined injection of the high molecular weight dextran and vasopressin led as soon as the first minutes (5 min) to the intensification of glycolysis. This was testified to by the reduction of glycogen concentration by 19.4 percent, elevation of the phosphorylase "A" activity by 30-36 percent and of the pyruvic acid by 36.9 percent. The ATP, ADP, AMP, and the KP concentration remained unchanged. The observed glycolysis changes can be regarded as the initial metabolic reactions resulting from hypoxia originating in microcirculation disturbances.

[Biokinetic behavior and metabolic effect of fructose in high dose continuous infusion in the rat]. / Biokinetisches Verhalten und Stoffwechselwirkungen von Fructose bei hochdosierter Dauerinfusion an der Ratte

The steady-state blood level of fructose during 24 hours intravenous infusion in response to different doses follows saturation kinetics. Even after toxic doses of 1.5 g/kg/h no depletion of liver adenine nucleotides can be observed after 24 hours. In the kidneys, however, ATP, ADP and total adenine nucleotides were decreased after a dose of 1.5 g/kg/h of fructose. The blood glucose increased continuously at infusion rates of 1.5 g/kg/h. Inorganic phosphate in the blood increased at doses of 1.0 and 1.5 g/kg/h. The weight of the kidneys increased, presumably through water uptake. Urinary secretion was drastically reduced at doses above 1.0 g/kg/h. An appreciable activity of ketohexokinase can be demonstrated in the kidneys.

Needle biopsy for muscle chemistry.

Needle biopsy can readily provide samples of human skeletal muscle for biochemical analysis. Muscle metabolites are measured by enzymic microanalytical techniques and electrolytes by neutron-activation analysis. This paper summarises the methods of analysis, gives the normal ranges for muscle contents of metabolites and electrolytes, and reviews the reported changes in a number of neuromuscular and metabolic disorders. Muscle is a fairly homogeneous tissue in health, but replacement with fat and fibrous tissue in myopathies causes error in analyses unless metabolites are referred to a reliable standard. It is recommended that needle-biopsy samples to be freeze-dried and dissected to remove connective tissue before analysis. Total creatine (phosphorylcreatine+free creatine) total adenosine+inosine nucleotides, and potassium and phosphorus separtely correlated very highly with sample dry weight after dissection, suggesting that these may be used as standards. When assessing whether a given metabolite is present in an abnormal amount, it is probaby advisable to check the content with reference to more than one standard, since one or more of these may be changed in disease.

Studies on the therapeutic use of Mercurascar. Part III. Influence of Mercurascan on some metabolic changes in experimental myocardial ischaemia in dogs. Section I: Energetic and ionic metabolism.

In experimental studies on dogs, the authors investigated the effect of small does of mercurascan (MSC) on metabolism of the heart muscle damaged by ischaemia. MSC is selectively accumulated and fixed in tissue damaged by ischaemia. MSC was demostrated to inhibit severe disturbances of metabolism in the ischaemic focus. It improves energy metabolism in the damaged tissue by maintaining the concentrations of nucleotides, creatinephosphate and total creatine at a higher level, thereby increasing the energy potential level of the adenylate system. Further, MSC decreases lactate concentration in tissue and reestablishes the disturbed ionic balance. By an hitherto unknown mechanism MSC regulates concentrations of potassium and sodium ions in the ischaemic focus and prevents increased hydration of tissue. Improved metabolic relations in the ischaemic tissue contribute towards normalisation of the heart action.