Hepatic function in rats after spaceflight: effects on lipids, glycogen, and enzymes

1987 ◽  
Vol 252 (2) ◽  
pp. R222-R226 ◽  
Author(s):  
A. H. Merrill ◽  
E. Wang ◽  
D. P. Jones ◽  
J. L. Hargrove
Keyword(s):  
Specific Activity ◽  
Cytochrome B5 ◽  
Hepatic Metabolism ◽  
Microsomal Protein ◽  
Hepatic Function ◽  
Tyrosine Aminotransferase ◽  
Fatty Acyl ◽  
Blood Cholesterol ◽  
Serine Palmitoyltransferase ◽  
Coa Reductase

The inclusion of rats aboard Spacelab 3 (SL-3) allowed analyses of liver lipids, glycogen, hepatic enzymes of cholesterol, glycerolipid and sphingolipid biosynthesis, and other enzyme activities. Glycogen content was markedly elevated in livers from the flight animals compared with controls. Cholesterol was 24% (P less than 0.04) lower in livers from the experimental groups, whereas blood cholesterol was 19% higher (P less than 0.05). The activity of 3-hydroxy-3-methylglutaryl-CoA reductase, the rate-limiting enzyme of steroid biosynthesis, was 80% lower (P less than 0.01). Total phospholipids and sphingolipid levels did not differ significantly. The specific activity of fatty acyl-CoA synthetase, which is responsible for activation of fatty acids, was 37% (P less than 0.05) higher in microsomes from the rats on SL-3; however, since these animals had 25% less microsomal protein (P less than 0.02), there was no difference per gram of liver. The initial enzymes of sphingolipid and glycerolipid biosynthesis were assayed; serine palmitoyltransferase was 40% lower (P less than 0.01), and glycerol 3-phosphate acyltransferase did not differ. Hepatic cytochrome P-450 content decreased by 50% after spaceflight. Enzymes that did not differ significantly between the two groups include cytochrome b5, glutathione S-transferase, tyrosine aminotransferase, aspartate aminotransferase, and cystathionase. These findings suggest that spaceflight alters hepatic metabolism of several classes of compounds.

scholarly journals Activation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in homogenates of developing rat brain

1979 ◽  
Vol 182 (2) ◽  
pp. 367-370 ◽  
Author(s):  
W A Maltese ◽  
J J Volpe
Keyword(s):  
Rat Brain ◽  
Cholesterol Synthesis ◽  
Specific Activity ◽  
Postnatal Period ◽  
Developing Brain ◽  
Brain Maturation ◽  
Assay Mixture ◽  
Coa Reductase ◽  
Developing Rat ◽  
Homogenization Medium

The specific activity of 3-hydroxy-3-methylglutaryl-CoA reductase increases when homogenates of developing rat brain are incubated at 37 degrees C or kept on ice. This increase is completely blocked by the addition of F- to the homogenization medium and the assay mixture. The capacity for activation of the reductase is greatest during the early postnatal period and declines as brain maturation proceeds. The data suggest that catalytic modification of the reductase may play a role in the regulation of cholesterol synthesis in the developing brain.

Long-chain-fatty-acyl-CoA reductase

1993 ◽  
pp. 219-221
Author(s):  
Dietmar Schomburg ◽  
Margit Salzmann ◽  
Dörte Stephan
Keyword(s):  
Fatty Acyl ◽  
Coa Reductase ◽  
Long Chain

Acclimation to Copper by Rainbow Trout,Salmo gairdneri: Biochemistry

1987 ◽  
Vol 44 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Darrel Jon Laurén ◽  
D. G. McDonald
Keyword(s):  
Rainbow Trout ◽  
Specific Activity ◽  
Gill Tissue ◽  
Microsomal Protein ◽  
Whole Body ◽  
Salmo Gairdneri ◽  
Copper Accumulation ◽  
Copper Exposure ◽  
Copper Uptake ◽  
Liver Copper

Whole body, gill, and liver copper uptake, gill Na+-K+-ATPase specific activity, and gill and liver acid-soluble thiols (AST), glutathione, and cysteine of rainbow trout (Salmo gairdneri) were measured during 28 d of exposure to 55 μg copper∙L−1. Na+-K+-ATPase specific activity was inhibited by 33% within 24 h of copper exposure, but this was compensated by a significant increase in microsomal protein so that the total Na+-K+-ATPase activity per milligram of gill tissue returned to normal by day 14. There was no accumulation of copper and no increase in AST, glutathione, or cysteine in the gill. However, after 7 d of exposure, hepatic AST and glutathione had increased by about 2 times, and a sulfhydryl-rich, acid-soluble protein, tentatively identified as metallothionein, increased by 2.8 times. Copper accumulation was highest in the liver, but other tissues also accumulated copper.

scholarly journals Developmentally regulated enzymes and cyclic AMP-binding sites in Dictyostelium discoideum cells blocked during development by α-chymotrypsin

1982 ◽  
Vol 206 (2) ◽  
pp. 185-193
Author(s):  
J A Schmidt ◽  
J L Stirling
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Binding Sites ◽  
Glycogen Phosphorylase ◽  
Specific Activity ◽  
Tyrosine Aminotransferase ◽  
Carbohydrate Binding ◽  
Threonine Deaminase ◽  
Developmentally Regulated ◽  
Beta Glucosidase

When cells of the slime mould Dictyostelium discoideum are allowed to starve in the presence of alpha-chymotrypsin, they are blocked in development at the stage where tight aggregates form tips. Analysis of developmentally regulated enzymes has shown that alpha-mannosidase, beta-N-acetylglucosaminidase, threonine deaminase, tyrosine aminotransferase, beta-glucosidase and the carbohydrate-binding protein discoidin are unaffected, but enzymes that show an increase in specific activity during post-aggregative development, namely glycogen phosphorylase, UDP-glucose pyrophosphorylase, UDP-galactose 4-epimerase, UDP-galactose polysaccharide transferase and alkaline phosphatase, did not show the characteristic increase when development was blocked by alpha-chymotrypsin. Recovery of cells from the effects of alpha-chymotrypsin was accompanied by the formation of fruiting bodies and a concomitant increase in the specific activity of UDP-glucose pyrophosphorylase. Uptake or efflux of 45Ca2+ was not altered in the presence of alpha-chymotrypsin. Cells allowed to develop in alpha-chymotrypsin, or treated with the enzyme for 15 min, had a markedly reduced ability to bind cyclic AMP with low affinity; high-affinity binding was unaffected. Pronase had a similar effect on cyclic AMP binding, but trypsin, which does not alter developmental processes, has no effect on cyclic AMP binding to D. discoideum cells.

scholarly journals A Fatty Acyl Coenzyme A Reductase Promotes Wax Ester Accumulation in Rhodococcus jostii RHA1

2017 ◽  
Vol 83 (20) ◽  
Author(s):  
James Round ◽  
Raphael Roccor ◽  
Shu-Nan Li ◽  
Lindsay D. Eltis
Keyword(s):  
Specific Activity ◽  
Dry Weight ◽  
Fatty Acyl ◽  
Wax Esters ◽  
Wax Ester ◽  
Wild Type ◽  
Considerable Potential ◽  
Commodity Chemicals ◽  
Acyl Coenzyme A ◽  
Rhodococcus Jostii

ABSTRACT Many rhodococci are oleaginous and, as such, have considerable potential for the sustainable production of lipid-based commodity chemicals. Herein, we demonstrated that Rhodococcus jostii RHA1, a soil bacterium that catabolizes a wide range of organic compounds, produced wax esters (WEs) up to 0.0002% of its cellular dry weight during exponential growth on glucose. These WEs were fully saturated and contained primarily 31 to 34 carbon atoms. Moreover, they were present at higher levels during exponential growth than under lipid-accumulating conditions. Bioinformatics analyses revealed that RHA1 contains a gene encoding a putative fatty acyl coenzyme A (acyl-CoA) reductase (FcrA). The purified enzyme catalyzed the NADPH-dependent transformation of stearoyl-CoA to stearyl alcohol with a specific activity of 45 ± 3 nmol/mg · min and dodecanal to dodecanol with a specific activity of 5,300 ± 300 nmol/mg · min. Deletion of fcrA did not affect WE accumulation when grown in either carbon- or nitrogen-limited medium. However, the ΔfcrA mutant accumulated less than 20% of the amount of WEs as the wild-type strain under conditions of nitric oxide stress. A strain of RHA1 overproducing FcrA accumulated WEs to ∼13% cellular dry weight under lipid-accumulating conditions, and their acyl moieties had longer average chain lengths than those in wild-type cells (C17 versus C16). The results provide insight into the biosynthesis of WEs in rhodococci and facilitate the development of this genus for the production of high-value neutral lipids. IMPORTANCE Among the best-studied oleaginous bacteria, rhodococci have considerable potential for the sustainable production of lipid-based commodity chemicals, such as wax esters. However, many aspects of lipid synthesis in these bacteria are poorly understood. The current study identifies a key enzyme in wax ester synthesis in rhodococci and exploits it to significantly improve the yield of wax esters in bacteria. In so doing, this work contributes to the development of novel bioprocesses for an important class of oleochemicals that may ultimately allow us to phase out their unsustainable production from sources such as petroleum and palm oil.

Optimization of Phosphatidylserine-Modified Titanium Surfaces for Enhanced Osteoblast Response

2006 ◽  
Author(s):  
Neera Satsangi ◽  
Arpan Satsangi ◽  
Joo L. Ong ◽  
Rajiv V. Satsangi
Keyword(s):  
Alkaline Phosphatase ◽  
Protein Production ◽  
Specific Activity ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Separate Experiment ◽  
Calcium Deposition ◽  
Fatty Acyl Chain ◽  
Acyl Chain Length

This report is part of a continued effort to evaluate the in vitro osteoblast responses on different phospholipid coatings on Titanium (Ti) implant materials. It has been established that, among analogous phopholipids, the Ti surfaces coated with calcium phosphate (CaP) complex of phosphatidylserine induce the best calcium deposition and osteoblast growth and metabolism. This communication describes an effort to optimize the chemical structure of phosphatidylserine at its position−1 and −2, as Ti surface coating relative to enhancement in osteoblast differentiation and growth in culture. Four synthetic phosphatidylserine analogs with varying fatty acyl chain length and unsaturation were converted to CaP complex, coated on Ti discs, and the osteoblast progenitor cells were cultured on them for up to 14 days to study their differentiation, growth and biochemistry as marked by the expression of alkaline phosphatase specific activity and protein production. In a separate experiment, the topography of the glass surface (glass Petri-dishes) coated the analogous phosphatidylserines, after immersion in simulated body fluid, was examined by scanning electron microscopy (SEM). The presence of calcium and phosphate ions in this deposit was also confirmed. The inclusion of unsaturation in fatty acyl chain in phosphatidylserine enhanced the Total protein production (TPP) as well as the alkaline phosphatase (ALP) specific activity.

Etoposide kinetics in patients with obstructive jaundice.

1990 ◽  
Vol 8 (6) ◽  
pp. 1101-1107 ◽  
Author(s):  
K R Hande ◽  
S N Wolff ◽  
F A Greco ◽  
J D Hainsworth ◽  
G Reed ◽  
...  
Keyword(s):  
Obstructive Jaundice ◽  
Urinary Excretion ◽  
Hepatic Metabolism ◽  
Study Groups ◽  
Hepatic Function ◽  
Volume Of Distribution ◽  
Metabolic Clearance ◽  
Total Clearance ◽  
Dose Reductions ◽  
Made In

The kinetics and urinary excretion of etoposide and etoposide glucuronide were determined in 11 patients with obstructive jaundice (bilirubin greater than 2.0 mg/dL) and in 23 patients with normal renal and hepatic function. Mean (+/- SE) measurements of clearance (24.5 +/- 2.06 v 26.5 +/- 2.05 mL/min/m2), half-life (5.7 +/- 0.5 v 6.4 +/- 0.5 hours), and volume of distribution (12.4 +/- 1.1 v 13.7 +/- 1.6 L/m2) were not significantly different in patients with jaundice when compared with controls. Similarly, etoposide kinetics in three patients determined during a period of hyperbilirubinemia were not different from measurements made in the same patients following resolution of their obstructive jaundice. In patients with jaundice, 46% of an administered etoposide dose was excreted in the urine as etoposide compared with 35% in controls (P = .15). Urinary excretion of etoposide glucuronide accounted for 29% of an administered etoposide dose in control patients and 15% in those with hepatic obstruction (P = .03). Biliary etoposide excretion measured in four patients with T-tubes was insignificant (less than 2.0% of an administered dose). The calculated renal clearance of etoposide was 11.5 mL/min/m2 in patients with jaundice and 10.4 mL/min/m2 in controls (P = .53). Respective metabolic clearance was 4.9 and 6.9 mL/min/m2 in these two study groups (P = .13). Although hepatic metabolism of etoposide may be slightly decreased in patients with obstructive jaundice, a modest increase in renal etoposide excretion appears to compensate for this change, so that total clearance is similar in the patients with jaundice when compared with controls. No etoposide dose reductions appear to be needed in treating patients with obstructive jaundice who have normal renal function.

scholarly journals Selenocysteine-Containing Proteins in Anaerobic Benzoate Metabolism of Desulfococcus multivorans

2004 ◽  
Vol 186 (7) ◽  
pp. 2156-2163 ◽  
Author(s):  
Franziska Peters ◽  
Michael Rother ◽  
Matthias Boll
Keyword(s):  
Trace Elements ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Model Organism ◽  
Strictly Anaerobic ◽  
Coa Ligase ◽  
Coa Reductase ◽  
Aliphatic Carboxylic Acids ◽  
Desulfococcus Multivorans

ABSTRACT The sulfate-reducing bacterium Desulfococcus multivorans uses various aromatic compounds as sources of cell carbon and energy. In this work, we studied the initial steps in the aromatic metabolism of this strictly anaerobic model organism. An ATP-dependent benzoate coenzyme A (CoA) ligase (AMP plus PPi forming) composed of a single 59-kDa subunit was purified from extracts of cells grown on benzoate. Specific activity was highest with benzoate and some benzoate derivatives, whereas aliphatic carboxylic acids were virtually unconverted. The N-terminal amino acid sequence showed high similarities with benzoate CoA ligases from Thauera aromatica and Azoarcus evansii. When cultivated on benzoate, cells strictly required selenium and molybdenum, whereas growth on nonaromatic compounds, such as cyclohexanecarboxylate or lactate, did not depend on the presence of the two trace elements. The growth rate on benzoate was half maximal with 1 nM selenite present in the growth medium. In molybdenum- and/or selenium-depleted cultures, growth on benzoate could be induced by addition of the missing trace elements. In extracts of cells grown on benzoate in the presence of [75Se]selenite, three radioactively labeled proteins with molecular masses of ∼100, 30, and 27 kDa were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The 100- and 30-kDa selenoproteins were 5- to 10-fold induced in cells grown on benzoate compared to cells grown on lactate. These results suggest that the dearomatization process in D. multivorans is not catalyzed by the ATP-dependent Fe-S enzyme benzoyl-CoA reductase as in facultative anaerobes but rather involves unknown molybdenum- and selenocysteine-containing proteins.

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