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Chatterjee T, Haldar D, Mallik S, Sarkar GN, Das S, Lahiri SK. A study on habits of tobacco use among medical and non-medical students of Kolkata. Lung India 2011; 28:5-10. [PMID: 21654978 PMCID: PMC3099511 DOI: 10.4103/0970-2113.76293] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Age-old practice "using tobacco" is a well known major global concern as it victimizes all its lovers by a host of chronic noncommunicable diseases including cancer; all develop very slowly and silently, and can cause premature death. OBJECTIVES To assess the pattern of tobacco use among the medical and nonmedical college students. MATERIALS AND METHODS A cross-sectional descriptive study was carried out in Kolkata collecting anonymous data from 515 medical and 349 nonmedical college students of two medical and two general colleges, selected randomly. RESULT Overall prevalence of tobacco use (18.3% vs 43.6%) and smoking (14.9% vs 40.7%) were significantly less in medical subjects, both across the sex and years of study. Lower rate of tobacco adoption at college level, higher quitting rate, correct knowledge regarding uselessness of filter attached with cigarette, and ill-effects of tobacco consumption were observed among medical participants. More nonmedical subjects were increasingly smoking compared to medical students. Filter-tipped cigarette was the top choice, and smoking was more prevalent mode of use among the nonmedical participants, most (62.3%) of whom were mild users. Curiosity was the top influencing factor for the initiation of tobacco use and two-third users wanted to quit. CONCLUSION Although the mortal habits was comparatively less among medical students, the medical environment seemed to fail to curb the dreadful practice totally. Thereby it can be recommended that active behavior-changing communication is required for all sections of the society to tear out the social root of the problem instead of unimpressive vague health warnings in vogue.
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Haldar D, Chatterjee T, Mallik S, Sarkar GN, Das SK, Lahiri S. A study on habits of tobacco use among medical and non-medical students of Kolkata. Lung India 2011; 28:319-20. [PMID: 22084556 PMCID: PMC3213729 DOI: 10.4103/0970-2113.85748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Haldar D, Freeman KB, Work TS. The site of synthesis of mitochondrial proteins in Krebs II ascites-tumour cells. Biochem J 2010; 102:684-90. [PMID: 16742481 PMCID: PMC1270315 DOI: 10.1042/bj1020684] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
At 22 degrees in Earle's medium, Krebs cells synthesize proteins. After a brief ;pulse' with [(14)C]valine followed by a ;chase' of [(12)C]valine the radioactivity appears first in microsomes and is transferred after ;chase' to the cell sap. Kinetics of labelling of the mitochondrial protein are different from that of either microsomal or cell-sap protein. When Krebs cells in buffer are mixed with ribonuclease in water the nuclease penetrates the cell membrane. The ribonuclease-treated cells are still viable but have lost most of their cytoplasmic ribosomes (electron micrograph). Such cells still synthesize mitochondrial protein at near normal rate but synthesis of microsomal protein is severely inhibited. The results indicate that some mitochondrial proteins are synthesized independently of the microsome-cell-sap system.
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Freeman KB, Haldar D, Work TS. The morphological site of synthesis of cytochrome c in mammalian cells (Krebs cells). Biochem J 2010; 105:947-52. [PMID: 16742570 PMCID: PMC1198412 DOI: 10.1042/bj1050947] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In Krebs ascites-tumour cells, cytochrome c is segregated in the mitochondria and the level in microsomes could not be measured. At 22 degrees in glucose-buffer Krebs cells synthesized a spectrum of proteins including cytochrome c. Mild osmotic shock in the presence of ribonuclease had little effect on incorporation of [(14)C]-leucine or [(14)C]valine into mixed mitochondrial protein but strongly inhibited synthesis of non-mitochondrial cytoplasmic proteins. Under these conditions, labelling of cytochrome c was also strongly inhibited. After pulse labelling of Krebs cells at 22 degrees for 10min. the cytcchrome radioactivity found in mitochondria was higher than in microsomes. After addition of unlabelled amino acid as ;chase' there was 137% increase in radioactivity of cytochrome c but only a 3% increase in radioactivity of whole-cell protein. It is concluded that the peptide chain of cytochome c is synthesized on cytoplasmic ribosomes. Mitochondria therefore do not have the character of self-replicating entities, but are formed by the cooperative function of messenger RNA of cytoplasmic ribosomes and, possibly, of intramitochondrial messenger derived from the mitochondrial DNA.
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Haldar D, Sarkar AP, Bisoi S, Mondal P. Assessment of client's perception in terms of satisfaction and service utilization in the central government health scheme dispensary at Kolkata. Indian J Community Med 2008; 33:121-3. [PMID: 19967039 PMCID: PMC2784620 DOI: 10.4103/0970-0218.40883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 12/05/2007] [Indexed: 12/02/2022] Open
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Adams C, Haldar D, Kamakaka RT. Construction and characterization of a series of vectors for Schizosaccharomyces pombe. Yeast 2006; 22:1307-14. [PMID: 16358314 DOI: 10.1002/yea.1332] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A set of vectors was created to allow cloning and expression studies in Schizosaccharomyces pombe. These vectors had a uniform backbone with an efficient Sz. pombe ARS, ARS3002, but different selectable markers--his3+, leu1+, ade6+ and ura4+. The vectors functioned efficiently as autonomously replicating plasmids that could also be converted into integrating vectors. The ura4+-containing vector was used to construct a Sz. pombe genomic library.
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Maji SK, Haldar D, Banerjee A, Mukhopadhyay C, Banerjee A. Conformational Heterogeneity of a Tripeptide in the Solid State and in Solution: Characterization of a g-Turn Containing Incipient Hairpin in Solution. J STRUCT CHEM+ 2003. [DOI: 10.1023/b:jory.0000029816.31278.7b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Biswas NR, Gupta SK, Das GK, Kumar N, Mongre PK, Haldar D, Beri S. Evaluation of Ophthacare eye drops--a herbal formulation in the management of various ophthalmic disorders. Phytother Res 2001; 15:618-20. [PMID: 11746845 DOI: 10.1002/ptr.896] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
An open prospective multicentre clinical trial was conducted in patients suffering from various ophthalmic disorders namely, conjunctivitis, conjunctival xerosis (dry eye), acute dacryocystitis, degenerative conditions (pterygium or pinguecula) and postoperative cataract patients with a herbal eye drop preparation (Ophthacare) containing basic principles of different herbs which have been conventionally used in the Ayurvedic system of medicine since time immemorial. These include Carum copticum, Terminalia belirica, Emblica officinalis, Curcuma longa, Ocimum sanctum, Cinnamomum camphora, Rosa damascena and meldespumapum. These herbs reportedly possess antiinfective and antiinflammatory properties. The present study was undertaken to elucidate the role of this herbal product in a variety of eye ailments. Side effects, if any, were noted during the study. An improvement was observed with the treatment of the herbal eye drop treatment in most cases. There were no side effects observed during the course of the study and the eye drop was well tolerated by the patients. The herbal eye drop Ophthacare has a useful role in a variety of infective, inflammatory and degenerative ophthalmic disorders.
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Balija VS, Chakraborty TR, Nikonov AV, Morimoto T, Haldar D. Identification of two transmembrane regions and a cytosolic domain of rat mitochondrial glycerophosphate acyltransferase. J Biol Chem 2000; 275:31668-73. [PMID: 10924502 DOI: 10.1074/jbc.m002963200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The topography of rat glycerophosphate acyltransferase (GAT) in the transverse plane of the mitochondrial outer membrane (MOM) was investigated. Computer analysis of the amino acid (aa) sequence derived from rat mitochondrial GAT cDNA (GenBanktrade mark accession nos. and ) predicts the presence of two possible transmembrane domains (aa 473-493 and 574-594) separated by an 80-aa stretch (aa 494-573). To determine the actual orientation of the native protein, we prepared anti-peptide antibodies to three regions: one in between (aa 543-559) and the other two (aa 420-435 and 726-740) flanking the two putative transmembrane regions. Both immunoreaction and immunoprecipitation experiments employing intact and solubilized mitochondria indicate that regions on the N- and C-terminal sides of the transmembrane regions are sequestered on the inner surface of the MOM, while the region between the transmembrane domains is present on the cytosolic face of the MOM. Additionally, two green fluorescent protein (GFP) fusion proteins consisting of full-length GAT fused to GFP at either the C terminus or inserted 115 amino acids from the N terminus were also constructed to determine the orientation of the N and C termini. COS-1 cells expressing these fusion proteins were fractionated to obtain mitochondria. Protease digestion of intact and solubilized COS-1 cell mitochondria revealed that the GFP domains of these fusion proteins are sequestered on the inner side of the MOM. The present findings indicate that GAT is a dual-spanning, transmembrane protein adopting an inverted "U" conformation in the transverse plane of the MOM, where the N and C termini are sequestered on the inner surface of the MOM, while aa 494-573 are exposed on the cytosolic surface of the MOM.
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Chakraborty TR, Vancura A, Balija VS, Haldar D. Phosphatidic acid synthesis in mitochondria. Topography of formation and transmembrane migration. J Biol Chem 1999; 274:29786-90. [PMID: 10514455 DOI: 10.1074/jbc.274.42.29786] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The topography of formation and migration of phosphatidic acid (PA) in the transverse plane of rat liver mitochondrial outer membrane (MOM) were investigated. Isolated mitochondria and microsomes, incubated with sn-glycerol 3-phosphate and an immobilized substrate palmitoyl-CoA-agarose, synthesized both lyso-PA and PA. The mitochondrial and microsomal acylation of glycerophosphate with palmitoyl-CoA-agarose was 80-100% of the values obtained in the presence of free palmitoyl-CoA. In another series of experiments, both free polymyxin B and polymyxin B-agarose stimulated mitochondrial glycerophosphate acyltransferase activity approximately 2-fold. When PA loaded mitochondria were treated with liver fatty acid binding protein, a fifth of the phospholipid left the mitochondria. The amount of exportable PA reduced with the increase in the time of incubation. In another approach, PA-loaded mitochondria were treated with phospholipase A(2). The amount of phospholipase A(2)-sensitive PA reduced when the incubation time was increased. Taken together, the results suggest that lysophosphatidic acid (LPA) and PA are synthesized on the outer surface of the MOM and that PA moves to the inner membrane presumably for cardiolipin formation.
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Schlame M, Zhao M, Rua D, Haldar D, Greenberg ML. Kinetic analysis of cardiolipin synthase: a membrane enzyme with two glycerophospholipid substrates. Lipids 1995; 30:633-40. [PMID: 7564918 DOI: 10.1007/bf02537000] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Mitochondrial cardiolipin synthase catalyzes the transfer of a phosphatidyl moiety from phosphatidyl-CMP (PtdCMP) to phosphatidylglycerol (PtdGro) in the presence of specific divalent cations. The synthase was solubilized from Saccharomyces cerevisiae mitochondria and purified about 300-fold. The partially enzyme was part of a medium-size, mixed micelle which had to bind to a foreign substrate/detergent micelle before catalysis could occur. The kinetics of cardiolipin synthase were studied by changing the molar fraction of substrate in the micelles. The enzyme obeyed Michaelis-Menten kinetics in relation to PtdCMP with a Km of 0.03 mol%. PtdGro caused sigmoidal kinetics with a low apparent affinity. It is speculated that it was involved in docking the enzyme to the substrate/detergent micelle. Cardiolipin synthase did not catalyze isotope exchange between [14C]CMP and PtdCMP, virtually excluding a ping-pong catalytic mechanism. Mg2+ stimulated the activity by increasing the turnover number rather than the substrate affinity, a mechanism which was also found for the Co(2+)-activation of rat liver cardiolipin synthase. It is concluded that a direct association of the metal ion and the enzyme forms the active cardiolipin synthase which has a very high affinity for PtdCMP and a lower affinity for PtdGro.
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Vancura A, Haldar D. Purification and characterization of glycerophosphate acyltransferase from rat liver mitochondria. J Biol Chem 1994; 269:27209-15. [PMID: 7961630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Glycerophosphate acyltransferase (GAT) catalyzes the conversion of sn-glycerol 3-phosphate to lysophosphatidic acid (LPA), the first and committed step of triacylglycerol and phospholipid synthesis. In spite of the important regulatory roles GAT may play in this biosynthetic pathway, little information is available on the structure, biochemical properties, and regulation of GAT from eukaryotic cells. We solubilized GAT from rat liver mitochondrial membranes and purified it to an apparent homogeneity by hydroxylapatite chromatography, preparative isoelectric focusing, and gel filtration. The enzyme is composed of a single polypeptide of 85 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography of the native protein. The GAT activity was completely lost during the purification procedure and required addition of exogenous phospholipids for its reconstitution. Since a high phospholipid to detergent ratio was needed for full reactivation, it is concluded that GAT requires "lipid boundary" for reconstitution. The ability of different phospholipids to reactivate GAT decreased in the following order: phosphatidylglycerol (PG), phosphatidylethanolamine (PE), phosphatidylcholine (PC), asolectin, phosphatidylinositol (PI), phosphatidylserine (PS), and cardiolipin. 1,2-Dioleoyl derivatives of PG and PE were more effective in reconstituting the GAT activity than corresponding dipalmitoyl derivatives. The GAT activation was further increased by using a combination of PG and PE or PG and PC. Regardless of the phospholipid used for reconstitution, palmitoyl-CoA was the best acyl donor and LPA was the only reaction product.
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Vancura A, Haldar D. Purification and characterization of glycerophosphate acyltransferase from rat liver mitochondria. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)46970-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Schlame M, Haldar D. Cardiolipin is synthesized on the matrix side of the inner membrane in rat liver mitochondria. J Biol Chem 1993; 268:74-9. [PMID: 8380172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In the mitochondrial inner membrane, cardiolipin is a specific lipid component associated with various protein complexes. The assembly of such complexes has been studied, and it seems that most protein subunits enter the inner membrane from the matrix side, but nothing is known about the path of cardiolipin. In this paper, the topography of cardiolipin biosynthesis is investigated. Cardiolipin synthase, a membrane-bound protein, could not be released by sonication or 1 M KCl. In sucrose density gradient subfractionation, cardiolipin synthase co-migrated with the inner membrane marker cytochrome oxidase. no indication was obtained for a preferential localization of this enzyme at contact sites between the outer and inner membranes. Protease digestion experiments showed that cardiolipin synthase exposed protease-susceptible domains mainly to the matrix side of the inner membrane. In intact mitochondria, the Mn(2+)-dependent stimulation of cardiolipin synthesis was abolished when the Mn2+ influx into the matrix was blocked by ruthenium red. 1-Decanoyl-sn-glycero-3-phosphorylcholine, a water-soluble inhibitor of cardiolipin synthase, was only effective after disintegration of mitochondria. The metabolic precursor of cardiolipin, CDP-diacylglycerol, was synthesized by an inner membrane enzyme whose protease-susceptible domains were mainly exposed to the matrix side. It is concluded that cardiolipin is synthesized in the inner leaflet of the mitochondrial inner membrane.
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Schlame M, Haldar D. Cardiolipin is synthesized on the matrix side of the inner membrane in rat liver mitochondria. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)54116-8] [Citation(s) in RCA: 121] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Simonian J, Haldar D, Delmaestro E, Trombetta LD. Effect of disulfiram (DS) on mitochondria from rat hippocampus: metabolic compartmentation of DS neurotoxicity. Neurochem Res 1992; 17:1029-35. [PMID: 1324439 DOI: 10.1007/bf00966832] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This experiment was designed to study the acute effects of disulfiram on mitochondrial enzymes in nonsynaptic and synaptic mitochondria from rat hippocampus. Cytochrome c oxidase, monoamine oxidase-B, glycerolphosphate acyltransferase and beta-hydroxybutyrate dehydrogenase were studied. Differences in enzyme activity were seen in controls. Cytochrome c oxidase activity was higher in synaptic mitochondria whereas glycerolphosphate acyltransferase activity was higher in nonsynaptic mitochondria. Mitochondria from disulfiram treated rats, particularly synaptic mitochondria, exhibited lower specific activities of cytochrome c oxidase and monoamine oxidase-B. These alterations were not limited to either the inner or outer mitochondrial membrane. Transmission electron microscopy revealed that mitochondria from disulfiram treated rats were severely altered in isolated preparations as well as in those from whole tissue. This study shows that disulfiram exerts a differential effect on mitochondrial subpopulations.
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Vancura A, Haldar D. Regulation of mitochondrial and microsomal phospholipid synthesis by liver fatty acid-binding protein. J Biol Chem 1992; 267:14353-9. [PMID: 1629224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Recently we have detected and partially purified a 15-kDa cytosolic L-alpha-lysophosphatidic acid (LPA)-binding protein (LPABP), which stimulates export of LPA from mitochondria (Vancura, A., Carroll, M. A., and Haldar, D. (1991) Biochem. Biophys. Res. Commun. 175, 339-343). Now we have purified this protein to homogeneity. By Western immunoblot analysis, amino acid sequence analysis, and binding characteristics we have shown that LPABP is identical with liver fatty acid-binding protein (L-FABP). This protein binds LPA, and stimulates mitochondrial and microsomal glycerophosphate acyltransferase (GAT) and the export of LPA from both the organelles. The mitochondrially synthesized LPA exported by L-FABP can be converted to phosphatidic acid by microsomes. L-FABP also stimulates microsomal conversion of LPA to phosphatidic acid but strongly inhibits this reaction in mitochondria. However, in the absence of L-FABP mitochondria predominantly synthesize PA. Taken together, these findings are suggestive that L-FABP plays a major role in mitochondrial and microsomal phospholipid metabolism by regulating both the synthesis and utilization of LPA.
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Vancura A, Haldar D. Regulation of mitochondrial and microsomal phospholipid synthesis by liver fatty acid-binding protein. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)49719-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Vancura A, Carroll MA, Haldar D. A lysophosphatidic acid-binding cytosolic protein stimulates mitochondrial glycerophosphate acyltransferase. Biochem Biophys Res Commun 1991; 175:339-43. [PMID: 1998517 DOI: 10.1016/s0006-291x(05)81240-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Rat liver cytosolic fraction caused up to five fold stimulation of mitochondrial glycerophosphate acyltransferase apparently by removing the lysophosphatidic acid formed by the acyltransferase. When mitochondria were incubated with palmityl-CoA, [2-3H]-sn-glycerol 3-phosphate and the cytosolic fraction and the supernatant fluid of the incubated mixture was passed through a Sephadex G-100 column, labeled lysophosphatidic acid eluted in three peaks with Mrs (i) 60-70 kDa, (ii) 10-20 kDa, and (iii) less than 5 kDa. Proteins, responsible for binding of lysophosphatidic acid in peaks (i) and (ii), were purified to near homogeneity as judged by electrophoretic analysis. The lysophosphatidic acid binding protein in peak (i) appears to be serum albumin and peak (iii) represents largely unbound lysophosphatidic acid. The 15 kDa protein, purified from peak (ii), bound lysophosphatidic acid, stimulated the acyltransferase and export of lysophosphatidic acid from mitochondria.
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Haldar D, Lipfert L. Export of mitochondrially synthesized lysophosphatidic acid. J Biol Chem 1990; 265:11014-6. [PMID: 2358449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We have previously demonstrated that the properties of mitochondrial glycerophosphate acyltransferase are in keeping with the asymmetric distribution of fatty acids found in naturally occurring cell glycerophospholipids. We are now examining if mitochondria can export lysophosphatidic acid and if it is converted to other phospholipids by the microsomes. Rat liver mitochondria were incubated for 3 min with [2-3H]-sn-glycerol 3-phosphate, palmityl-CoA, and N-ethylmaleimide in the acyltransferase assay medium. In the absence of bovine serum albumin in the medium, greater than 80% of the phospholipids sedimented with the mitochondria. In the presence of the albumin, the lysophosphatidic acid was present entirely in the supernatant fluid. The very little phosphatidic acid that was formed sedimented with the mitochondria. Addition of microsomes to the supernatant fluid followed by a further incubation of 5 min converted 61% of the lysophosphatidic acid to phosphatidic acid which sedimented with the microsomes. When mitochondria and microsomes were incubated together in the assay medium containing albumin and N-ethylmaleimide, the product contained more phosphatidic and less lysophosphatidic acid. When the subcellular components were reisolated by differential centrifugation, 70% of the phosphatidic acid sedimented with the microsomes and the lysophosphatidic acid stayed in the postmicrosomal supernatant. Thus, under appropriate conditions mitochondrially produced lysophosphatidic acid can leave the organelles and this phospholipid can be converted to phosphatidic acid by the microsomes.
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Saili A, Sarna MS, Haldar D, Kumari S, Dutta AK. Delayed cesarean section: neonatal outcome. Indian Pediatr 1990; 27:601-4. [PMID: 2253997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
One hundred and twenty one consecutive cesarean sections producing single term, appropriate for gestational age neonates, out of which 85% were emergency cesareans, were included in this study. Fetal distress, nonprogress of labour, and cephalopelvic disproportion were major indications for surgery. The waiting period varied from less than 30 minutes to greater than 4 hours. More than 50% of neonates studied suffered from some problem. The morbidity increased significantly if cesarean section was delayed for more than two hours.
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Hesler CB, Olymbios C, Haldar D. Transverse-plane topography of long-chain acyl-CoA synthetase in the mitochondrial outer membrane. J Biol Chem 1990; 265:6600-5. [PMID: 2182622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Transverse-plane topography of mitochondrial outer-membrane long-chain acyl-CoA synthetase was investigated using proteases as probes for exposure of crucial domains, i.e. domains containing the active site or otherwise required for enzymatic activity. Incubation of intact mitochondria with the nonspecific proteases proteinase K and subtilisin resulted in a time-dependent loss of 90% or more of the long-chain acyl-CoA synthetase activity compared to control incubations. The integrity of the outer membrane before and during this treatment was shown by cytochrome c oxidase latency as well as the stability of adenylate kinase activity in the presence of protease. After a 15-min incubation in these conditions, site-specific proteases such as trypsin and chymotrypsin had only a limited inhibitory effect (29 and 58% loss of activity, respectively); however, treatment of hypotonically disrupted mitochondria with these proteases resulted in increased (71 and 77%, respectively) loss of activity. Exposure of trypsin-sensitive crucial domains on the inner surface of the membrane was directly demonstrated by incubation of trypsin-loaded outer-membrane vesicles. Together, these results suggest that mitochondrial long-chain acyl-CoA synthetase is a transmembrane enzyme, possessing crucial domains on both sides of the outer membrane. However, the cytosolic exposure of the enzyme does not appear to be affected by a change in the medium ionic strength as seen previously for other outer-membrane enzymes. In an experiment investigating the topography of the active site of the enzyme, an immobilized substrate analog, desulfo-CoA-agarose, was preincubated with intact mitochondria. This resulted in up to a 42% loss of the activity of long-chain acyl-CoA synthetase, consistent with a cytosolic exposure for at least the CoA-binding domain of the active site.
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Pavlica RJ, Hesler CB, Lipfert L, Hirshfield IN, Haldar D. Two-dimensional gel electrophoretic resolution of the polypeptides of rat liver mitochondria and the outer membrane. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1022:115-25. [PMID: 2302398 DOI: 10.1016/0005-2736(90)90407-f] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The proteins of highly purified rat liver mitochondria were resolved by two-dimensional polyacrylamide gel electrophoresis, and detected by staining with either Coomassie blue or silver. Approximately 250 polypeptides were detected with silver staining which is 2- to 3-times that observed with Coomassie blue. Silver staining was especially more effective than Coomassie blue for detecting polypeptides of less than 50 000 daltons. A two-dimensional gel pattern of rat liver microsomes was distinct from that of the mitochondria. The mitochondrial outer membrane was prepared from purified mitochondria either with digitonin or by swelling in a hypotonic medium. As assessed by marker enzymes, the latter method yielded a considerably purer outer membrane preparation (20-fold purification) than the former (2.6-fold purification). Approximately 50 polypeptides were observed in a two-dimensional gel (pH 3-10) of the highly purified outer membrane fraction. Three isoelectric forms of the pore (VDAC) protein were observed with pI values of 8.2, 7.8 and 7.1. Monoamine oxidase was identified as a polypeptide of Mr 60 000. About 50 polypeptides were also resolved in a reverse polarity non-equilibrium pH gradient electrophoresis gel of the outer membrane, pH 3-10, with at least six isoelectric forms of the VDAC protein observed under these conditions. The six isoforms of the VDAC protein were also observed in a non-equilibrium gel with 2 micrograms of the purified protein.
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