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1.
Public Health ; 166: 108-120, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30476779

RESUMO

OBJECTIVES: The aim of this study was to investigate the effects of primary healthcare decentralization on type 2 diabetes mellitus mortality and morbidity in different municipalities of a developing country. STUDY DESIGN: This was a retrospective study based on a panel of annual data from 5560 Brazilian municipalities from 2000 to 2011. METHODS: The investigation used the staggered municipal adoption of a federal health information program as a quasi-experiment to identify the treatment effects of health decentralization on diabetes indicators. Using Difference-in-Differences models and instrumental variables, we analyzed the effects of primary healthcare decentralization on diabetes rates (i.e. diabetes deaths and hospitalizations by the number of people with a diabetes diagnosis and by population). RESULTS: Evidence suggests improvements in universal access to primary health care and progress in the average health outcomes related to diabetes mortality (reduction of 30%) and hospitalization (reduction of 2.3%) due to decentralization. Effects are further pronounced in developed regions with higher incomes, while the poorest and less developed regions showed virtually no effect. CONCLUSIONS: These results demonstrate that there are particular preconditions for successful primary health decentralization, especially related to returns of scale (big health facilities are associated with low cost per treatment), lack of human and physical capital, and government coordination problems.


Assuntos
Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/terapia , Política , Atenção Primária à Saúde/organização & administração , Brasil/epidemiologia , Cidades , Diabetes Mellitus Tipo 2/mortalidade , Acessibilidade aos Serviços de Saúde , Hospitalização/estatística & dados numéricos , Humanos , Estudos Retrospectivos , Fatores Socioeconômicos
2.
Nat Cell Biol ; 2(10): 754-61, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11025668

RESUMO

Recent evidence supports the theory that mitochondrial homeostasis is the key regulatory step in apoptosis through the actions of members of the Bcl-2 family. Pro-apoptotic members of the family, such as Bax, Bad and Bid, can induce the loss of outer-membrane integrity with subsequent redistribution of pro-apoptotic proteins such as cytochrome c that are normally located in the intermembrane spaces of mitochondria. The anti-apoptotic members of the family, such as Bcl-2 and Bcl-XL, protect the integrity of the mitochondrion and prevent the release of death-inducing factors. Bid normally exists in an inactive state in the cytosol, but after cleavage by caspase 8, the carboxy-terminal portion (tBid) moves from cytosol to mitochondria, where it induces release of cytochrome c. Here we address the question of what mediates specific targeting of tBid to the mitochondria. We provide evidence that cardiolipin, which is present in mitochondrial membranes, mediates the targeting of tBid to mitochondria through a previously unknown three-helix domain in tBid. These findings implicate cardiolipin in the pathway for cytochrome c release.


Assuntos
Cardiolipinas/metabolismo , Proteínas de Transporte/metabolismo , Mitocôndrias/metabolismo , Transporte Proteico , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Apoptose , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3 , Grupo dos Citocromos c/metabolismo , Membranas Intracelulares/metabolismo , Fragmentos de Peptídeos/metabolismo
3.
J Cell Biol ; 144(4): 673-85, 1999 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-10037789

RESUMO

LY-A strain is a Chinese hamster ovary cell mutant resistant to sphingomyelin (SM)-directed cytolysin and has a defect in de novo SM synthesis. Metabolic labeling experiments with radioactive serine, sphingosine, and choline showed that LY-A cells were defective in synthesis of SM from these precursors, but not syntheses of ceramide (Cer), glycosphingolipids, or phosphatidylcholine, indicating a specific defect in the conversion of Cer to SM in LY-A cells. In vitro experiments showed that the specific defect of SM formation in LY-A cells was not due to alterations in enzymatic activities responsible for SM synthesis or degradation. When cells were treated with brefeldin A, which causes fusion of the Golgi apparatus with the endoplasmic reticulum (ER), de novo SM synthesis in LY-A cells was restored to the wild-type level. Pulse-chase experiments with a fluorescent Cer analogue, N-(4,4-difluoro-5,7-dimethyl-4-bora-3a, 4a-diaza-s-indacene-3-pentanoyl)-D-erythro-sphingosine (C5-DMB-Cer), revealed that in wild-type cells C5-DMB-Cer was redistributed from intracellular membranes to the Golgi apparatus in an intracellular ATP-dependent manner, and that LY-A cells were defective in the energy-dependent redistribution of C5-DMB-Cer. Under ATP-depleted conditions, conversion of C5-DMB-Cer to C5-DMB-SM and of [3H]sphingosine to [3H]SM in wild-type cells decreased to the levels in LY-A cells, which were not affected by ATP depletion. ER-to-Golgi apparatus trafficking of glycosylphosphatidylinositol-anchored or membrane-spanning proteins in LY-A cells appeared to be normal. These results indicate that the predominant pathway of ER-to-Golgi apparatus trafficking of Cer for de novo SM synthesis is ATP dependent and that this pathway is almost completely impaired in LY-A cells. In addition, the specific defect of SM synthesis in LY-A cells suggests different pathways of Cer transport for glycosphingolipids versus SM synthesis.


Assuntos
Trifosfato de Adenosina/metabolismo , Ceramidas/metabolismo , Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Esfingomielinas/biossíntese , Animais , Transporte Biológico Ativo , Brefeldina A/farmacologia , Células CHO , Radioisótopos de Carbono , Cricetinae , Retículo Endoplasmático/efeitos dos fármacos , Metabolismo Energético , Corantes Fluorescentes/metabolismo , Complexo de Golgi/efeitos dos fármacos , Metabolismo dos Lipídeos , Modelos Biológicos , Mutação , Esfingomielinas/metabolismo
4.
Mater Sci Eng C Mater Biol Appl ; 98: 753-763, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30813081

RESUMO

The bioactivity of anodized near-ß TiNbSn alloy with low Young's modulus prepared in sulfuric acid electrolytes was examined to explore the osseointegration mechanism with a focus on the role of anodic oxide. Hydroxyapatite (HA) precipitated on the surface of anodic oxide following immersion in Hank's solution, and precipitation accelerated with increase in the sulfuric acid concentration of the electrolyte. HA is formed on the surface of as-anodized oxide without subsequent annealing or hot water (HW) treatment. This outcome differs from that of a previous study using anodized TiNbSn alloy prepared in acetic acid electrolytes requiring for subsequent HW treatment. It was found that the oxide anodized in sulfuric acid electrolyte contains a large amount of internal pores and is highly crystallized thick TiO2, whereas the same prepared in the acetic acid electrolyte is low crystalline thin TiO2 containing a small amount of pores. The present anodized TiNbSn alloy is preferred for maintaining the low Young's modulus of the alloy and eliminating the subsequent treatment to increase the Young's modulus. A model to rationalize the bioactivity of the present anodic oxide is proposed based on the series of studies. It is concluded that the sulfuric acid electrolyte is favorable for both HA formation and low Young's modulus, and the bioactivity is attributed to the anodic TiO2 that facilitates incorporation of bone ingredients.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Eletrólitos , Ácidos Sulfúricos/química
5.
Sci Rep ; 7(1): 13883, 2017 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-29093529

RESUMO

Proteins in solution are conventionally considered macromolecules. Dynamic microscopic structures in supersaturated protein solutions have received increasing attention in the study of protein crystallisation and the formation of misfolded aggregates. Here, we present a method for observing rotational dynamic structures that can detect the interaction of nanoscale lysozyme protein networks via diffracted X-ray tracking (DXT). Our DXT analysis demonstrated that the rearrangement behaviours of lysozyme networks or clusters, which are driven by local density and concentration fluctuations, generate force fields on the femtonewton to attonewton (fN - aN) scale. This quantitative parameter was previously observed in our experiments on supersaturated inorganic solutions. This commonality provides a way to clarify the solution structures of a variety of supersaturated solutions as well as to control nucleation and crystallisation in supersaturated solutions.


Assuntos
Muramidase/química , Nanoestruturas/química , Soluções/química , Difração de Raios X/métodos , Dicroísmo Circular , Compostos de Ouro/química , Modelos Estatísticos , Rotação
6.
Biochim Biophys Acta ; 1348(1-2): 151-6, 1997 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-9370327

RESUMO

Phosphatidylserine (PtdSer) in mammalian cells is synthesized through an exchange of free L-serine for the base moiety of pre-existing phospholipids. Studies on PtdSer biosynthesis in Chinese hamster ovary (CHO) cells have suggested that the serine base-exchange is catalyzed by at least two different enzymes; one, named PtdSer synthase I (PSS I), uses phosphatidylcholine (PtdCho) and possibly phosphatidylethanolamine (PtdEtn) as phosphatidyl donors for the serine base-exchange, and the other, named PtdSer synthase II (PSS II), uses PtdEtn but not PtdCho as a phosphatidyl donor. Recently, cDNAs of the PSS I and II have been isolated from CHO-K1 cells. This review will briefly describe the current understanding of PtdSer synthases of mammalian cells, mainly CHO cells.


Assuntos
Isoenzimas/metabolismo , Transferases de Grupos Nitrogenados/metabolismo , Sequência de Aminoácidos , Animais , Células CHO , Clonagem Molecular , Cricetinae , Isoenzimas/química , Isoenzimas/genética , Dados de Sequência Molecular , Transferases de Grupos Nitrogenados/química , Transferases de Grupos Nitrogenados/genética , Conformação Proteica , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
7.
Biochim Biophys Acta ; 986(1): 61-9, 1989 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-2479418

RESUMO

The effects of phosphatidylserine starvation on the infection with Sindbis virus (an enveloped RNA virus) have been investigated in a Chinese hamster ovary (CHO) cell mutant (strain PSA-3) which requires exogenously added phosphatidylserine for cell growth because it lacks the ability to synthesize this phospholipid. When PSA-3 cells were grown in the absence of phosphatidylserine, the cellular contents of phosphatidylserine and also phosphatidylethanolamine produced through decarboxylation of phosphatidylserine decreased. Sindbis virus production in the mutant cells decreased immediately upon phosphatidylserine deprivation as did the contents of phosphatidylserine and phosphatidylethanolamine, whereas the cell growth, viability, and syntheses of protein, DNA and RNA remained normal for approx. 40 h phosphatidylserine starvation. Although PSA-3 cells grown without phosphatidylserine for 24 h were able to bind and internalize Sindbis virus almost normally, viral RNA synthesis was greatly reduced in the cells, suggesting that nucleocapsids of internalized Sindbis virus are not normally released into the cytoplasm. Unlike mammalian cell mutants defective in endosomal acidification, PSA-3 cells grown without phosphatidylserine were not resistant to diphtheria toxin. Furthermore, the yield of virions and viral RNA synthesis in PSA-3 cells were not completely restored on brief exposure of the cells to low pH medium following virus adsorption, which is known to induce artificial fusion of the viral envelope with the plasma membrane of normal host cells and then injection of viral nucleocapsids into the cytoplasm. Our data demonstrate the requirement of membrane phospholipids, such as phosphatidylserine and/or phosphatidylethanolamine, in CHO cells for Sindbis virus infection, and we discuss their possible roles.


Assuntos
Transformação Celular Viral , Fosfatidiletanolaminas/biossíntese , Fosfatidilserinas/biossíntese , Sindbis virus/genética , Animais , Divisão Celular , Linhagem Celular , Cloroquina/farmacologia , Cricetinae , Cricetulus , DNA/biossíntese , DNA Viral/biossíntese , Toxina Diftérica/farmacologia , Feminino , Cinética , Metionina/metabolismo , Mutação , Ovário , Biossíntese de Proteínas , RNA/biossíntese , RNA Viral/biossíntese , Sindbis virus/efeitos dos fármacos
8.
Biochim Biophys Acta ; 692(2): 177-86, 1982 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-7171591

RESUMO

The intracellular transport and secretion of immunoglobulin G1(IgG1) by mouse MOPC-31C plasmacytoma cells were analyzed from the viewpoint of the roles of phospholipids. The membrane phospholipids were modified by culturing cells in a medium supplemented with choline analogues, N,N'-dimethylethanolamine or N-monomethylethanolamine, and accordingly the membranes were enriched in phosphatidyl-N,N'-dimethylethanolamine or phosphatidyl-N-monomethylethanolamine (Maeda, M., Tanaka, Y. and Akamatsu, Y. (1980) Biochem. Biophys. Res. Commun. 96, 876-881). The modified cells were pulse-labeled with L-[35S]methionine and the secretion of labeled IgG1 was chased. Half of the IgG1 was exported to the extracellular medium 1-1.5 h and 2-3 h after synthesis by choline- and dimethylethanolamine-supplemented cells, respectively. However, most of the newly synthesized IgG1 was not secreted by monomethylethanolamine-supplemented cells, even after 5 h; it remained within the cells. The sensitivity of intracellular IgG1 to endoglycosidase H was examined for probing the movement of IgG1 from the rough endoplasmic reticulum to the Golgi complex. Half of the newly synthesized IgG1 acquired resistance to endoglycosidase H after 30-45 min, 1-1.5 h and 2-3 h in choline-, dimethylethanolamine- and monomethylethanolamine-supplemented cells, respectively. Thus, the transport of IgG1 was markedly retarded by the modification with choline analogues, dimethylethanolamine or monomethylethanolamine, at least in the following two processes, from the rough endoplasmic reticulum to the Golgi complex and from the Golgi to the outside of cells. Modification with monomethylethanolamine was more effective than that with dimethylethanolamine in slowing down the transport of IgG1 and appeared to cause accumulation of IgG1 within the cells. A morphological study was also carried out for the three kinds of cell. The roles of phospholipids in the processes of membrane flow are discussed.


Assuntos
Deanol/farmacologia , Etanolaminas/farmacologia , Imunoglobulina G/metabolismo , Plasmocitoma/imunologia , Animais , Transporte Biológico/efeitos dos fármacos , Linhagem Celular , Colina/metabolismo , Cinética , Camundongos , Neoplasias Experimentais/imunologia , Fosfolipídeos/metabolismo
9.
Biochim Biophys Acta ; 845(3): 324-32, 1985 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-2988643

RESUMO

We have developed a new selection procedure for mammalian cell mutants defective in protein export by the use of diphtheria toxin, and devised a new screening method for defective protein secretion using nitrocellulose membranes. By the combination of these procedures, we have isolated a temperature-sensitive mutant clone of Chinese hamster ovary cells which shows a pleiotropic defect in protein export. This mutant, designated DS28-6, is temperature-sensitive for growth. Secretion of a series of proteins is markedly inhibited at the non-permissive temperature. These proteins seem to be normally synthesized and accumulated within the cell at the non-permissive temperature and secreted upon shift down to the permissive temperature. When this mutant is infected with vesicular stomatitis virus, oligosaccharide processing of G-protein is arrested at an endoglycosidase-H-sensitive stage at the non-permissive temperature. The lesion of this mutant appears to be in the endoplasmic reticulum or the cis Golgi or both.


Assuntos
Mutação , Proteínas/genética , Animais , Divisão Celular , Linhagem Celular , Cricetinae , Cricetulus , Feminino , Ovário , Proteínas/metabolismo , Temperatura , Vírus da Estomatite Vesicular Indiana/metabolismo , Proteínas Virais/metabolismo
10.
Biochim Biophys Acta ; 794(2): 298-306, 1984 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-6733139

RESUMO

The interactions of PE and its N-methylated derivatives (PME, PDE AND PC) WITH Ca2+ were examined. PE and the intermediate phospholipids of PE N-methylation (PME and PDE) interacted with Ca2+ in a pH-dependent and reversible manner. When these phospholipids were present in the heptane phase, Ca2+ in the aqueous phase was translocated into the heptane phase at alkaline pH but not at acidic pH. PDE was also effective for the translocation even at around neutral pH, while PC hardly translocated Ca2+ at pH 6.0-9.2. The amounts of Ca2+ interacting with these phospholipids were in the following order: PDE is greater than PME is greater than PE is much greater than PC. P1, phosphatidic acid and PS interacted with Ca2+ in the whole pH range examined. The Ca2+ interactions with P1 and phosphatidic acid were independent of pH, while PS interacted with more Ca2+ at alkaline pH. These phospholipids interacted with Ca2+ most strongly among the cations studied. Liposomes containing PDE also bound the highest amounts Ca2+ among PE and its N-methylated derivatives. Furthermore, mammalian cultured cell membranes, which contain increased amounts of PDE by in vivo modification with N,N'-dimethylethanolamine, bound more Ca2+ than those prepared from choline-treated control cells.


Assuntos
Cálcio/metabolismo , Membrana Celular/metabolismo , Fosfatidiletanolaminas/metabolismo , Animais , Células Cultivadas , Cricetinae , Feminino , Concentração de Íons de Hidrogênio , Lipossomos/metabolismo , Metilação , Ácidos Fosfatídicos/metabolismo , Fosfatidilinositóis/metabolismo , Fosfatidilserinas/metabolismo
11.
Biochim Biophys Acta ; 1051(3): 221-9, 1990 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-2178689

RESUMO

Cultured Chinese hamster ovary (CHO) cells possess an insulin-sensitive facilitated diffusion system for glucose transport. Mutant clones of CHO cells defective in glucose transport were obtained by repeating the selection procedure, which involved mutagenesis with ethyl methanesulfonate, radiation suicide with tritiated 2-deoxy-D-glucose, the polyester replica technique and in situ autoradiographic assaying for glucose accumulation. On the first selection, we obtained mutants exhibiting about half the glucose uptake activity of parental CHO-K1 cells and half the amount of a glucose transporter, the amount of which was determined by immunoblotting with an antibody to the human erythrocyte glucose transporter. The second selection, starting from one of the mutants obtained in the first-step selection, yielded a strain, GTS-31, in which both glucose uptake activity and the quantity of the glucose transporter were 10-20% of the levels in CHO-K1 cells, whereas the responsiveness of glucose transport to insulin, and the activities of leucine uptake and several glycolytic enzymes remained unchanged. GTS-31 cells grew slower than CHO-K1 cells at both 33 and 40 degrees C, and in a medium containing a low concentration of glucose (0.1 mM), the mutant cells lost the ability to form colonies. All the three spontaneous GTS-31 cell revertants, which were isolated by growing the mutant cells in medium containing 0.1 mM glucose, exhibited about half the glucose uptake activity and about half the amount of glucose transporter, as compared to in CHO-K1 cells, these characteristics being similar to those of the first-step mutant. These results indicate that the decrease in glucose uptake activity in strain GTS-31 is due to a mutation which induces a reduction in the amount of the glucose transporter, providing genetic evidence that the glucose transporter functions as a major route for glucose entry into CHO-K1 cells.


Assuntos
Glucose/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Ovário/metabolismo , Animais , Autorradiografia , Transporte Biológico/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Separação Celular , Cricetinae , Cricetulus , Desoxiglucose/farmacologia , Metanossulfonato de Etila/farmacologia , Feminino , Expressão Gênica/efeitos dos fármacos , Glucose/farmacologia , Immunoblotting , Insulina/farmacologia , Proteínas de Transporte de Monossacarídeos/genética , Mutação , Ovário/efeitos dos fármacos , Ovário/ultraestrutura , Sódio/farmacologia
12.
Biochim Biophys Acta ; 620(3): 356-63, 1980 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-7016184

RESUMO

Acyl phosphatidylglycerol, isolated from Escherichia coli, has been identified as 3-sn-phosphatidyl-1'-(3'-acyl)-sn-glycerol. The fatty acids of the diacylglycerol moiety of acyl phosphatidylglycerol resemble those of phosphatidylglycerol in composition. However, the monoacylglycerol moiety of this lipid contains more unsaturated fatty acids than the diacylglycerol part of this lipid or other phospholipids in E. coli. Furthermore, the fatty acids present in the monoacylglycerol moiety, were found to contain major amounts of an unsaturated acid identified as 7-tetradecenoic acid by combined gas-liquid chromatography-mass spectrometry. This acid was present only in low concentrations in most phospholipids of E. coli.


Assuntos
Escherichia coli/metabolismo , Fosfatidilgliceróis/isolamento & purificação , Diglicerídeos/análise , Ácidos Graxos/análise , Ácidos Graxos Insaturados/análise , Cromatografia Gasosa-Espectrometria de Massas , Glicerídeos/análise , Fosfatidilgliceróis/análise , Fosfolipídeos/análise
13.
Biochim Biophys Acta ; 663(1): 1-13, 1981 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-7011407

RESUMO

The incorporation of 2-acyl lysophospholipids into Escherichia coli, and their metabolism were studied. 2-[14C]Acyl lysophosphatidylethanolamine could penetrate into E. coli cells and was mainly incorporated into phosphatidylethanolamine. 2-Acyl lysophosphatidylethanolamine was partially degraded, but some of it was incorporated into membrane phospholipids by acylation. 2-Acyl lysophosphatidylcholine also entered cells and was acylated to phosphatidylcholine. The acylation of 2-acyl lysophospholipid by the envelope fraction was also studied. Fatty acids were incorporated into 2-acyl lysophospholipids by the envelope fraction in the presence of ATP and Mg2+, and the incorporation was stimulated by acyl carrier protein, but not by coenzyme A. No acylation was observed with acyl coenzyme A as acyl donor. The acylation activities of the inner and outer membranes were examined. Pathways for degradation and modification of membrane phospholipids in E. coli are proposed.


Assuntos
Escherichia coli/metabolismo , Lisofosfatidilcolinas/metabolismo , Lisofosfolipídeos , Lipídeos de Membrana/metabolismo , Fosfatidiletanolaminas/metabolismo , Radioisótopos de Carbono , Membrana Celular/metabolismo , Cinética , Ácidos Palmíticos/metabolismo , Fosfatidilcolinas/biossíntese , Fosfolipídeos/metabolismo
14.
Biochim Biophys Acta ; 528(1): 107-18, 1978 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-23168

RESUMO

The conversion of phosphatidylglycerol to acyl phosphatidylglycerol by extracts of Escherichia coli K-12 strains was examined under various conditions. The maximum rate of conversion was observed at pH 7.2 in the presence of 50% (v/v) diethyl ether and 10 mM CaCl2. This conversion was found to involve two sequential reactions: (1) The formation of 2-acyl glycerophosphoglycerol and 2-acyl glycerophosphoethanolamine from phosphatidylglycerol and phosphatidylethanolamine, respectively, by detergent-resistant phospholipase A in the presence of Ca2+ and (2) transfer of the acyl group of 2-acyl lysophospholipid to phosphatidylglycerol by a heat-labile factor(s) in the presence of diethyl ether. Neither fatty, acid acyl-CoA nor 1-acyl lysophospholipid could act as an acyl donor for phosphatidylglycerol. The heat-labile factor(s) was found in both the inner membrane and supernatant fractions.


Assuntos
Detergentes/farmacologia , Escherichia coli/metabolismo , Fosfatidilgliceróis/biossíntese , Fosfolipases/metabolismo , Cálcio/farmacologia , Membrana Celular/enzimologia , Etanolaminas/análise , Etil-Éteres , Ácidos Graxos/análise , Glicerofosfatos , Concentração de Íons de Hidrogênio , Modelos Biológicos , Fosfatidiletanolaminas , Fosfatidilgliceróis/metabolismo , Fosfolipídeos/biossíntese , Solventes , Temperatura
15.
Biochim Biophys Acta ; 1532(3): 223-33, 2001 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-11470243

RESUMO

Fission yeast lsd1 strains show aberrant mitosis with a lsd phenotype, large and small daughter nuclei, and a very thick septum, the phenotypic expression being temperature-sensitive. The lsd1(+) gene is the homologue of the budding yeast FAS2 gene encoding the fatty acid synthase alpha-subunit as reported previously (S. Saitoh, K. Takahashi, K. Nabeshima, Y. Yamashita, Y. Nakaseko, A. Hirata, M. Yanagida, J. Cell Biol. 134 (1996) 949--961). In this paper, lsd1 is considered to represent fas2. Here, three fas2 strains were investigated and found to have missense point mutations at different sites in the gene encoding the alpha-subunit of fatty acid synthase. The mutation affected only slightly the enzymatic activities monitored in vitro. Unexpectedly, abnormal phospholipids, phosphatidylcholine and phosphatidylethanolamine, both of which contain a very-long-chain fatty acyl residue (1-melissoyl-2-oleolyl-sn-glycero-3-phosphocholine and 1-melissoyl-2-oleolyl-sn-glycero-3-phosphoethanolamine), accumulated in fas2 strains in a temperature-sensitive manner. Rescue of the fas2 strains by addition of palmitate to the medium at restrictive temperature was accompanied by disappearance of these abnormal phospholipids. Accumulation of these lipids in membranes may cause alteration of various cellular functions.


Assuntos
Ácido Graxo Sintases/genética , Ácidos Graxos/química , Fosfolipídeos/metabolismo , Schizosaccharomyces/genética , Radioisótopos de Carbono , Cromatografia em Camada Fina , Ácido Graxo Sintases/análise , Cromatografia Gasosa-Espectrometria de Massas , Mutação , Fosfolipídeos/biossíntese , Fosfolipídeos/química , Schizosaccharomyces/química , Schizosaccharomyces/metabolismo , Temperatura
16.
J Endotoxin Res ; 7(3): 232-6, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11581576

RESUMO

Taxol, an antitumor agent derived from a plant, mimics the action of lipopolysaccharide (LPS) in mice, but not in humans. The LPS-mimetic activity of Taxol is not observed in LPS-hyporesponsive C3H/HeJ mice which possess a point mutation in Toll-like receptor 4 (TLR4); therefore, TLR4 appears to be involved in both Taxol and LPS signaling. In addition, TLR4 was recently shown to physically associate with MD-2, a molecule that confers LPS-responsiveness on TLR4. Here we examined whether or not TLR4/MD-2 complex mediates a Taxol-induced signal by using transformants of the mouse pro-B cell line, Ba/F3, expressing mouse TLR4 alone, both mouse TLR4 and mouse MD-2, and both mouse MD-2 and mouse TLR4 lacking the cytoplasmic portion. Our results demonstrated that co-expression of mouse TLR4 and mouse MD-2 was required for Taxol responsiveness, and that the TLR4/MD-2 complex is the shared molecule in Taxol and LPS signal transduction in mice. We also found that mouse MD-2, but not human MD-2, is involved in Taxol signaling, suggesting that MD-2 is responsible for the species-specific responsiveness to Taxol.


Assuntos
Antígenos de Superfície/imunologia , Antineoplásicos Fitogênicos/imunologia , Proteínas de Drosophila , Lipídeo A/análogos & derivados , Lipopolissacarídeos/imunologia , Glicoproteínas de Membrana/imunologia , Mimetismo Molecular/imunologia , Paclitaxel/imunologia , Receptores de Superfície Celular/imunologia , Transdução de Sinais/imunologia , Animais , Antígenos de Superfície/genética , Linhagem Celular , Meios de Cultura Livres de Soro , Expressão Gênica , Humanos , Lipídeo A/farmacologia , Antígeno 96 de Linfócito , Glicoproteínas de Membrana/genética , Camundongos , NF-kappa B/antagonistas & inibidores , Receptores de Superfície Celular/genética , Especificidade da Espécie , Receptor 4 Toll-Like , Receptores Toll-Like
17.
FEBS Lett ; 474(1): 63-5, 2000 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-10828452

RESUMO

Serine palmitoyltransferase (SPT), responsible for the initial step of sphingolipid biosynthesis, catalyzes condensation of palmitoyl coenzyme A and L-serine to produce 3-ketodihydrosphingosine (KDS). For determination of the stereochemical specificity of the amino acid substrate, a competition analysis of the production of [(3)H]KDS from L-[(3)H]serine was performed using purified SPT. D-Serine inhibited [(3)H]KDS production as effectively as non-radioactive L-serine, whereas neither D-alanine nor D-threonine showed any significant effect. Incubation of purified SPT with [palmitoyl 1-(14)C]palmitoyl coenzyme A and D-serine did not produce [(14)C]KDS, while the control incubation with L-serine did. These results suggest that D-serine competes with L-serine for the amino acid recognition site of SPT, but that D-serine is not utilized by this enzyme to produce KDS.


Assuntos
Aciltransferases/antagonistas & inibidores , Serina/farmacologia , Esfingolipídeos/biossíntese , Animais , Ligação Competitiva , Células CHO , Cricetinae , Palmitoil Coenzima A/metabolismo , Serina/metabolismo , Serina C-Palmitoiltransferase , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Estereoisomerismo , Relação Estrutura-Atividade , Especificidade por Substrato , Trítio
18.
FEBS Lett ; 417(2): 196-8, 1997 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-9395294

RESUMO

Curcumin, the major yellow pigment of turmeric (Curcuma longa), has strong anti-carcinogenic and anti-inflammatory activities. We examined the effects of curcumin on enzyme activities of the following phospholipases in a cell-free system: G protein-mediated phospholipase D (PLD), phosphatidylinositol-specific phospholipase C, and phospholipase A2 from mouse macrophage-like cell line J774.1 cells, sphingomyelinase from bovine brain, and phosphatidylcholine-phospholipase C from Bacillus cereus. Curcumin inhibited several types of phospholipases, most effectively PLD among those tested. It also inhibited 12-O-tetradecanoylphorbol-13-acetate-induced PLD activation in intact J774.1 cells in a dose-dependent manner. These results suggest that the anti-inflammatory and anti-carcinogenic action of curcumin is partly due to the inhibition of PLD.


Assuntos
Curcumina/farmacologia , Fosfolipase D/antagonistas & inibidores , Animais , Bacillus subtilis/enzimologia , Proteínas de Bactérias , Bovinos , Sistema Livre de Células , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Camundongos , Fosfolipases A/metabolismo , Fosfolipases A2 , Esfingomielina Fosfodiesterase/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Fosfolipases Tipo C/metabolismo
19.
FEBS Lett ; 192(2): 263-6, 1985 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-2998869

RESUMO

The effects of a monosaccharide precursor of Escherichia coli lipid A (lipid X) on murine macrophages were studied. Lipid X is a diacylglucosamine 1-phosphate bearing beta-hydroxymyristoyl groups at positions 2 and 3. Lipid X, as well as lipopolysaccharide and lipid A, enhanced O2- generation in mouse peritoneal macrophages and a macrophage-like cell line, J774.1, and further induced the tumor-cytotoxic activity of peritoneal macrophages. Elimination of a 1-phosphate or 3-O-beta-hydroxymyristoyl groups are essential for the elevated O2- generation and induction of tumoricidal activity due to lipid X.


Assuntos
Citotoxicidade Imunológica/efeitos dos fármacos , Escherichia coli/imunologia , Glicolipídeos/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Superóxidos/metabolismo , Animais , Linhagem Celular , Leucemia Experimental/imunologia , Lipídeo A/farmacologia , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos ICR
20.
FEBS Lett ; 395(2-3): 262-6, 1996 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-8898108

RESUMO

We have previously shown that a Chinese hamster ovary (CHO) cell mutant defective in phosphatidylserine synthase I recovers the enzyme activity on transfection with a pssA cDNA clone isolated from the parental CHO-K1. The resultant transfectant, CDT-1, exhibited about 20-fold higher specific activity of the enzyme in the membrane fraction than CHO-K1 cells. Polyclonal antibodies against two peptides of the predicted pssA product cross-reacted with a membrane protein having an apparent molecular mass of 42 kDa, which was overproduced in CDT-1 cells. By immunoprecipitation with the antibody, phosphatidylserine synthase I activity as well as the 42-kDa protein was eliminated from solubilized membrane proteins of CDT-1 cells. Both the enzyme activity and the 42-kDa protein of CHO-K1 cells were enriched in the mitochondria-associated membrane fraction and the microsome fraction, but neither was enriched in the mitochondria fraction or the cytosol fraction. These results suggest that the pssA gene encodes phosphatidylserine synthase I.


Assuntos
Proteínas de Membrana/metabolismo , Transferases de Grupos Nitrogenados , Transferases/metabolismo , Animais , Anticorpos , Células CHO , Cricetinae , Citosol/enzimologia , DNA Complementar , Immunoblotting , Cinética , Proteínas de Membrana/análise , Proteínas de Membrana/biossíntese , Microssomos/enzimologia , Mitocôndrias/enzimologia , Frações Subcelulares/enzimologia , Transfecção , Transferases/análise , Transferases/biossíntese
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