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Biomedical subjects

J C Kader

Publications and source records attributed to J C Kader.

54 records · Page 3Linked to original sources
PubMed1988

Effect of noradrenaline chronic administration on brown fat phospholipids.

Chronic cold exposure of rats (9 days at 5 degrees C) induces an alteration of the fatty acid composition of phospholipids in brown adipose tissue. The alteration is due to an increase of the unsaturation degree of these lipids. The phenomenon can be reproduced by 10(-7) mole. h-1 administration of noradrenaline for 9 days in rats kept at 25 degrees C. Thus, phospholipid alteration in brown fat of cold exposed rats is most probably a consequence of the increase of sympathetic tone which occurs in this tissue during exposure to cold.

Adipose Tissue, Brown↗
PubMed1987

The primary structure of spinach-leaf phospholipid-transfer protein.

The complete amino acid sequence phospholipid-transfer protein isolated from spinach leaves has been determined. The primary structure of the spinach protein was elucidated by analyses by HPLC of cyanogen bromide fragments and peptides obtained by tryptic digestions. The single polypeptide chain of the spinach protein consists of 91 amino acid residues. The protein contains six cysteines whereas phenylalanine and glutamine are absent. The present data, which are the first to be obtained with a phospholipid-transfer protein from a photosynthetic tissue, are compared to the amino acid sequences determined with plant and animal proteins involved in the intracellular transport of hydrophobic compounds.

Amino Acid Sequence↗
PubMed1986

Purification of an antibody-like protein from the sea star Asterias rubens (L.).

Cells from sea star (Asterias rubens) axial organs stimulated with trinitrophenyl (TNP) or fluoresceinyl-haptened polyacrylamide beads and subsequently stimulated in vitro with the same antigen produced and released a specific antibody-like protein which induced lysis of haptened sheep erythrocytes in the presence of serum complement. The anti-TNP antibody-like protein isolated by ammonium sulfate precipitation, gel filtration and affinity chromatography exhibited a single precipiting peak after crossed immunoelectrophoresis against rabbit antiserum to partially purified culture supernatant. The anti-TNP antibody-like protein gave a specific affinity precipitate in crossed affino-electrophoresis using a p-nitrobenzoyl-substituted gel. The analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under both reducing and nonreducing conditions evidenced a unique 30-kDa polypeptide chain. According to gel filtration experiments, the molecular weight of the major component isolated by affinity chromatography was about four times higher. Therefore, the antibody-like molecule could be a tetrameric protein devoid of any disulfide bond.

Animals↗
PubMed1985

In vitro synthesis of a plant phospholipid transfer protein: a study by high performance liquid chromatography.

In order to study the biosynthesis of a plant phospholipid transfer protein (PLTP), poly (A)+RNAs have been prepared from maize seedlings and translated in vitro with a rabbit reticulocyte lysate. The newly synthesized proteins were then separated by fast protein liquid chromatography (FPLC) followed by SDS-PAGE or by high performance liquid chromatography (HPLC) coupled to a radioactivity detector monitor. It has been showed that a radioactive band comigrating with a 14C methylated pure PLTP was detected by SDS-PAGE. This result, confirmed by direct radioactive monitoring, indicates that PLTP is actively synthesized in vitro.

Carrier Proteins↗
PubMed1985

Purification and properties of plant cytochrome b5.

Microsomal cytochrome b5 was 352-fold purified from potato tubers with a yield of 10.4%. To our knowledge, this is the first report relating the purification of higher-plant cytochrome b5. Its Mr (16 700) and absorption spectrum are similar to those of animal and yeast cytochrome b5.

Chromatography, Gel↗
PubMed1984

Purification of a NADH-ferricyanide reductase from plant microsomal membranes with a zwitterionic detergent.

A microsomal NADH-ferricyanide reductase was purified to homogeneity from potato tubers. A zwitterionic detergent (CHAPS) was used for the extraction of this reductase which is the first to be purified from plant microsomal membranes. The successive steps of purification included an anion exchange column (DEAE-cellulose or DEAE-Trisacryl), a blue-Ultrogel affinity column and a gel filtration on Sephadex G75. The purification factor was 280 and the yield was 1.6%. The protein has an apparent molecular weight of 44,000 +/- 1,000 as estimated from SDS-PAGE. This successful purification opens new perspectives in the study of oleate desaturase of higher plants which is assumed to contain NADH-ferricyanide reductase as an essential component.

Cholic Acids↗
PubMed1984

Purification and characterization of a spinach-leaf protein capable of transferring phospholipids from liposomes to mitochondria or chloroplasts.

A phospholipid transfer protein has been purified 195-fold from an extract of spinach leaves. This protein is capable of transferring phosphatidylcholine, phosphatidylinositol, phosphatidylglycerol and phosphatidylethanolamine from liposomes to mitochondria. In addition to this protein, a minor part of the total activity was associated with a less purified fraction. The pure protein has an isoelectric point of 9.0 +/- 0.2 determined by a chromatofocusing technique. Electrophoresis on sodium dodecyl sulfate/polyacrylamide gel showed that the protein is homogeneous and has an apparent molecular weight of 9000 +/- 1000, in agreement with the value (8832) calculated from the amino acid composition. This composition is characterized by a high amount of alanine and glycine and by the absence of phenylalanine, whereas arginine, glutamine, histidine and methionine are minor components. The spinach protein is also able to transfer phosphatidylcholine and phosphatidylglycerol from liposomes to intact chloroplasts. This observation reinforces the hypothesis that plastid phospholipids are partly imported from outside the organelle by a transfer process.

Amino Acids↗
PubMed1982

Transfer of phospholipids between mesosomes and protoplasts from Bacillus subtilis.

1. Phospholipids were more intensively labelled from ammonium [1-14C]glycerophosphate in mesosomes than in protoplasts isolated from Bacillus subtilis. 2. When mesosomes, containing phospholipids labelled from sodium-[32P] phosphate were incubated with non radioactive protoplasts, labelled phospholipids were recovered in protoplasts after incubation. 3. This transfer of phospholipids from mesosomes toward protoplasts is time-dependent. 4. Soluble proteins obtained from Bacillus subtilis after ammonium sulphate precipitation were separated on a Sephadex G-100 column. 5. The two main fractions were able to accelerate the transfer of phospholipids from mesosomes toward protoplasts. 6. The first peak stimulated more actively the transfer of phosphatidylethanolamine whereas the second one preferentially accelerated the transfer of phosphatidylglycerol and diphosphatidylglycerol.

Bacillus subtilis↗
PubMed1980

Stimulation of phosphatidylethanolamine exchange by castor bean cytosol proteins.

Cytosol proteins prepared from castor bean endosperm (4-day-old) seedlings stimulate the exchange of [(3)H]phosphatidylethanolamine between liposomes and mitochondria. The acceleration of the exchange depends on the quantity of cytosol proteins, the time of incubation, and the respective amounts of liposomes and mitochondria. On a per seedling basis, the active proteins are essentially located in the endosperm, whereas the roots and the cotyledons are less rich in these proteins.

Journal Article↗
PubMed1978

Free flow electrophoresis of chloroplasts.

Highly purified intact chloroplasts were isolated from spinach (Spinacia oleracea L.) leaves by free flow electrophoresis. Morphological and biochemical studies showed that the fraction enriched in intact chloroplasts has a higher protein to chlorophyll ratio and a higher linolenic acid content than the broken organelles of the other fraction. The intact chloroplasts prepared by electrophoresis retained their capacity for CO(2) fixation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that this fraction was rich in stroma and lamellae proteins. Free flow electrophoresis, which separates organelles and molecules according to their surface charges, is a good technique for producing purified chloroplasts with complete physiological activities.

Journal Article↗
PubMed1977

Cyanide sensitivity and induction of the microsomal oleoyl-CoA desaturase of potato tuber.

1. The properties of oleoyl-CoA desaturase, induced in microsomal fractions by the 'ageing' treatment of potato tuber slices (aeration of slices for 3-18 h), were investigated to study the effect of cyanide on desaturation and cycloheximide on the induction of the desaturase. 2. The electrons needed for the desaturation can be supplied either by NADH or NADPH, but ascorbate can also drive the reaction; experiments with CO suggested that cytochrome P-450 was not involved in the desaturation. 3. A strong inhibition of the desaturation by potassium cyanide was observed with each of the electron donors; total inhibition was noticed with 1 mM KCN; low concentrations (0.1 mM) caused 50% inhibition of the desaturation. 5. The variation of the oleoyl-CoA desaturase activity during the ageing process and the drop in this activity in aged slices treated by cycloheximide indicate that the enzyme undergoes an active turnover.

Coenzyme A↗
PubMed1975

Proteins and the intracellular exchange of lipids. I. Stimulation of phospholipid exchange between mitochondria and microsomal fractions by proteins isolated from potato tuber.

1. An active fraction which stimulates the exchange of phospholipids between microsomal fractions and mitochondria was isolated by gel filtration from potato tuber homogenates. 2. This fraction is probably a protein since the stimulatory factor is nondialyzable and temperature-sensitive. The molecular weight of the active fraction is approximatively 22 000. 3. The addition of the stimulatory fraction increases essentially the exchange of the main phospholipids of the potato tuber organelles; phosphatidyl-inositol, phosphatidylcholine and phosphatidylethanolamine. 4. Inhibiting factors, probably lipid-degrading enzymes, are present in the total supernatant fraction and are responsible for the inhibiting effect on the exchange of lipids when the crude supernatant fraction is used. The "inhibition effect" is rather a degradation of the exchangeable phospholipid pools.

Chromatography, Gel↗
PubMedDate not supplied

Bifunctional lipid-transfer: fatty acid-binding proteins in plants.

A cytosolic protein, able to facilitate intermembrane movements of phospholipids in vitro, has been purified to homogeneity from sunflower seedlings. This protein, which has the properties of a lipid-transfer protein (LTP), is also able to bind oleoyl-CoA, as shown by FPLC chromatography. This finding, in addition to previous observations suggesting that a lipid-transfer protein from spinach leaves can bind oleic acid and that oat seedlings contain a fatty acid-binding protein with similar features than lipid transfer proteins, provides a clear demonstration that plant cells contain bifunctional fatty acid/lipid transfer proteins. These proteins can play an active role in fatty acid metabolism which involves movements of oleyl-CoA between intracellular membranes.

Acyl Coenzyme A↗