RESUMO
BACKGROUND: Loss-of-function homozygous or compound heterozygous mutations in IL36RN, which encodes interleukin-36 receptor antagonist (IL-36Ra), has been implicated in the pathogenesis of skin disorders. However, the pathogenic role of IL-36Ra in cutaneous ischemia-reperfusion (I/R) injury remains unclear. OBJECTIVES: We investigated the role of IL36Ra in cutaneous I/R injury. METHODS: We examined I/R injury in Il36rn-/- mice. The area of wounds, numbers of infiltrated cells, apoptotic cells and neutrophil extracellular trap (NET) formation were assessed. The expression levels of various genes were analysed using real-time RT-PCR. The expression of high mobility group box 1 (HMGB1), an endogenous toll-like receptor (TLR) 4 ligand, was confirmed using immunohistology, and serum HMGB1 levels were measured by ELISA. Cytokine production by stimulated cultured J774A.1 and HaCaT cells was examined. RESULTS: IL-36Ra deficiency resulted in significantly delayed wound healing and increased neutrophil and macrophage infiltration into the wound tissues. Il36rn-/- mice had increased mRNA expression levels of CXCL1, CXCL2, CCL4, TNF-α, TGF-ß, IL-1ß, IL-6 and IL-36γ relative to wild-type mice. Apoptosis was identified in keratinocytes by TUNEL assay. HMGB1 expression in the I/R site was decreased in both keratinocytes and adnexal cells, while serum HMGB1 levels were significantly elevated after reperfusion. The mRNA levels of various cytokines, including IL-1ß, were elevated in J774A.1 cells through TLR4 signalling by HMGB1 stimulation. In addition, HaCaT cells stimulated with IL-1ß showed significantly increased CXCL1, TNF-α, IL-6, IL-36ß and IL-36γ mRNA expression. Furthermore, NET formation was increased by IL-36Ra deficiency. Finally, either the blockade of TLR4 signalling by TAK-242 or inhibition of NET formation by Cl-amidine normalized exacerbated I/R injury in Il36rn-/- mice. CONCLUSIONS: This study indicated that IL-36Ra deficiency exacerbates cutaneous I/R injury due to excessive inflammatory cell recruitment, NET formation, and excessive cytokine and chemokine production via the TLR4 pathway by HMGB1 released from epidermal apoptotic cells.
Assuntos
Proteína HMGB1 , Traumatismo por Reperfusão , Animais , Citocinas , Proteína HMGB1/genética , Proteína HMGB1/metabolismo , Macrófagos/metabolismo , Camundongos , Traumatismo por Reperfusão/genética , Transdução de Sinais , Fator de Necrose Tumoral alfaRESUMO
This study evaluated the control of streptococcosis outbreaks in Brazil, isolated from diseased sorubim and identified as Lactococcus garvieae by genetic sequencing. This report determined the potential for lactococcosis control in sorubim Pseudoplatystoma sp. with two vaccines: an aqueous-based, whole-cell inactivated vaccine (bacterin) and an oil-adjuvanted bacterin. Their efficacy was evaluated at 30 days post-vaccination (d.p.v.) by challenge with L. garvieae, and the antibody production response at 15, 30 and 60 d.p.v. and the non-specific immune response were compared amongst treatments. High protection levels (P < 0.05) were achieved with the oil-adjuvanted vaccine with a relative percentage survival value of 81.7% at 30 d.p.v. Additionally, the oil-adjuvanted vaccine increased the immunogenicity of the bacterin as indicated by greater agglutination antibody titres from 15 until 60 d.p.v. This is the first report of a positive effect of vaccine administration on the specific immunity of sorubim, and the study showed that a specific antibody plays an important role in sorubim defence against lactococcosis because the innate immune responses were similar in all of the studied animals. These results demonstrated that oil-adjuvanted vaccine can be an effective alternative for the protection of sorubim from L. garvieae disease.
Assuntos
Vacinas Bacterianas/imunologia , Surtos de Doenças/veterinária , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/prevenção & controle , Infecções por Bactérias Gram-Positivas/veterinária , Lactococcus/imunologia , Vacinação/veterinária , Imunidade Adaptativa , Animais , Autovacinas/imunologia , Brasil/epidemiologia , Peixes-Gato , Surtos de Doenças/prevenção & controle , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Positivas/epidemiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/prevenção & controle , Lactococcus/isolamento & purificaçãoRESUMO
Multidrug resistance protein 4 (MRP4) is involved in the efflux of nucleoside derivatives and has a role in the determination of drug sensitivity. We investigated the relationship between MRP4 genetic polymorphisms and doses of the 6-mercaptopurine (6-MP) and methotrexate. Further, we evaluated the frequency of therapeutic interruption during maintenance therapy in Japanese children with acute lymphoblastic leukemia (ALL). Ninety-four patients received an initial 6-MP dose in the range of 30-50 mg m(-2) in this analysis. Patients with homozygous variant allele in any of MRP4 G2269A, C912A and G559T required high frequency of 6-MP dose reduction compared with non-homozygous individuals. Average 6-MP dose for patients with homozygous variant allele on either MRP4 or inosine triphosphate pyrophosphatase was significantly lower than that for patients with non-homozygous variant allele during maintenance therapy (30.5 versus 40.0 mg m(-2), P=0.024). Therefore, MRP4 genotyping may be useful for personalizing the therapeutic dose of 6-MP during the ALL maintenance therapy in Japanese.
Assuntos
Antimetabólitos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/uso terapêutico , Mercaptopurina/administração & dosagem , Mercaptopurina/uso terapêutico , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Polimorfismo Genético/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Alelos , Antimetabólitos Antineoplásicos/efeitos adversos , Pré-Escolar , Relação Dose-Resposta a Droga , Feminino , Variação Genética , Genótipo , Humanos , Japão , Masculino , Mercaptopurina/efeitos adversos , Pirofosfatases/genéticaAssuntos
Neoplasias Neuroepiteliomatosas/genética , Proteína EWS de Ligação a RNA/genética , Neoplasias da Medula Espinal/genética , Transativadores/genética , Proteínas Supressoras de Tumor/genética , Pré-Escolar , Humanos , Masculino , Gradação de Tumores , Neoplasias Neuroepiteliomatosas/patologia , Fusão Oncogênica , Medula Espinal/patologia , Neoplasias da Medula Espinal/patologiaAssuntos
Carboxiliases/genética , Eczema/genética , Hipo-Hidrose/genética , Miopatias Congênitas Estruturais/diagnóstico , Proteína ORAI1/genética , Biópsia , Pré-Escolar , Análise Mutacional de DNA , Dermoscopia , Eczema/patologia , Humanos , Hipo-Hidrose/patologia , Masculino , Músculo Esquelético/patologia , Miopatias Congênitas Estruturais/complicações , Miopatias Congênitas Estruturais/genética , Miopatias Congênitas Estruturais/patologia , Pele/diagnóstico por imagem , Pele/patologia , Glândulas Sudoríparas/patologiaRESUMO
Subtotal or total glossectomy for advanced tongue cancer has an adverse impact on swallowing. The purpose of this retrospective study was to analyse postoperative swallowing outcomes and to determine the ideal reconstruction method in these patients. The clinical and swallowing data of patients with tongue cancer who underwent subtotal glossectomy at the study institution between 2005 and 2019 were reviewed retrospectively. Data were available for 101 patients. The most common reconstruction method was a free rectus abdominis musculocutaneous flap (69 cases). The postoperative feeding tube dependency rate was 11.1% at discharge and 9.4% at 1 year. During the study period, laryngeal suspension and/or a cricopharyngeal myotomy was performed in 39 patients (38.6%), with 25 of these operations performed after 2017. Patients treated in 2017-2019 were significantly more able to take thin liquid (P < 0.001) and lost less weight (P = 0.015) compared to those treated in 2005-2016. Multivariate analysis of 61 patients who did not undergo laryngeal suspension and/or cricopharyngeal myotomy showed significant feeding tube dependency in those aged 65 years and older (P = 0.004). Thin liquid intake was significantly improved after subtotal glossectomy with laryngeal suspension, which led to better postoperative swallowing and improved quality of life.
Assuntos
Retalho Miocutâneo , Neoplasias da Língua , Humanos , Glossectomia/métodos , Deglutição , Neoplasias da Língua/cirurgia , Estudos Retrospectivos , Qualidade de VidaRESUMO
Diffuse pulmonary arteriovenous malformations (AVMs) are associated with a poor prognosis and the therapeutic strategy remains controversial. We describe a pediatric patient with diffuse pulmonary AVMs associated with hereditary hemorrhagic telangiectasia (HHT), who presented with two cerebral AVMs in the parietal and occipital lobes as well. Of note, successful bilateral lung transplantation not only improved the hypoxemia but also resulted in size reduction of the cerebral AVMs. Although it is essential to consider involvements other than pulmonary AVMs, especially brain AVMs, to decide the indication, lung transplantation can be a viable therapeutic option for patients with diffuse pulmonary AVMs and HHT.
Assuntos
Malformações Arteriovenosas/complicações , Pneumopatias/complicações , Transplante de Pulmão , Adolescente , Malformações Arteriovenosas/terapia , Feminino , Humanos , Malformações Arteriovenosas Intracranianas/complicações , Ataque Isquêmico Transitório/complicações , Pneumopatias/terapia , Telangiectasia Hemorrágica Hereditária/complicações , Telangiectasia Hemorrágica Hereditária/terapia , Resultado do TratamentoRESUMO
AIM: To demonstrate a capacity for producing exopolysaccharides (EPSs) and an ability to form biofilm on abiotic materials of Actinomyces oris strain K20. METHODOLOGY: The productivity of EPSs and the ability to form biofilm of strain K20 were evaluated by measuring viscosity of spent culture media and by scanning electron microscopy (SEM) and the biofilm assay on microtitre plates, respectively. High-performance liquid chromatography was used to determine the chemical composition of the viscous materials. To examine the role of the viscous materials attributable to the pathogenicity in this organism, the ability of strain K20 to induce abscess formation was compared in mice to that of ATCC 27044. RESULTS: The viscosity of the spent culture media of K20 was significantly higher than that of ATCC 27044. Strain K20 showed dense meshwork structures around the cells and formed biofilms on microtitre plates, whereas ATCC 27044 did not. Chemical analysis of the viscous materials revealed that they were mainly composed of neutral sugars with mannose constituting 77.5% of the polysaccharides. Strain K20 induced persistent abscesses in mice lasting at least 5 days at a concentration of 10(8) cells mL(-1), whereas abscesses induced by ATCC 27044 healed and disappeared or decreased in size at day 5. CONCLUSIONS: Strain K20 produced EPSs, mainly consisting of mannose, and formed biofilms. This phenotype might play an important role for A. oris to express virulence through the progression of apical periodontitis.
Assuntos
Actinomyces/patogenicidade , Infecções por Actinomycetales/microbiologia , Abscesso Periapical/microbiologia , Polissacarídeos Bacterianos , Actinomyces/classificação , Actinomyces/isolamento & purificação , Animais , Biofilmes , Meios de Cultura , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Filogenia , Especificidade da Espécie , Virulência , ViscosidadeRESUMO
The full-length of insulin-like growth factor (IGF) complementary (c)DNAs encoded by igf-I and igf-II from torafugu pufferfish Takifugu rubripes were cloned in the present study. The deduced amino acid sequences of the two genes showed c. 80% identity each with those of Igf-I and Igf-II from other teleosts, respectively. Two growth hormone (GH) receptors, ghr1 and ghr2, were also cloned in silico using the T. rubripes Fugu genome database. The transcripts of T. rubripes igf-I were detected in slow muscle, heart, skin, gill, liver and intestine but not in fast muscle, spleen and testis of adult fish, whereas those of igf-II were found in all tissues examined. Subsequently, the accumulated messenger (m)RNA levels of igf-I and igf-II were investigated in an F(2) population derived from a male of an apparent fast-growing T. rubripes strain and a wild female T. rubripes together with those of other growth-related genes encoding Gh, Ghr1 and Ghr2, and with those of prolactin (Prl) and leptin (Lep) previously reported. The accumulated mRNA levels of igf-I, gh and ghr1 were significantly correlated to growth rate at larval stages in the population, but not for those of igf-II, prl, ghr2 and lep. Although it is unclear whether or not this phenotype is directly related to the heredity of the fast-growing strain, the findings suggest that the expression of igf-I, gh and ghr1 is involved in the regulation of growth rate at larval stages in T. rubripes.
Assuntos
Tamanho Corporal , Regulação da Expressão Gênica , Hormônio do Crescimento/genética , Fator de Crescimento Insulin-Like I/genética , RNA Mensageiro/metabolismo , Receptores da Somatotropina/genética , Animais , Takifugu/anatomia & histologia , Takifugu/crescimento & desenvolvimentoRESUMO
More than half of orally administered N-cyclohexyl linoleamide-car-boxyl-C(14) yl-CI was recovered from feces of rats, and 30 to 50 percent of the absorbed carbon-14 activity was excreted in urine. N-Cyclohexyl linoleamide had an inhibitory eflect on the absorption of cholesterol from the thoracic duct and caused a decrease in the deposition of cholesterol in the livers of rats that had been fed cholesterol.
Assuntos
Colesterol/metabolismo , Ácidos Linoleicos/metabolismo , Ácidos Linoleicos/farmacologia , Amidas/metabolismo , Animais , Isótopos de Carbono/urina , Colesterol/análise , Fezes/análise , Fígado/metabolismo , Masculino , Camundongos , Coelhos , RatosRESUMO
A summer field survey off Point Barrow, Alaska, revealed that Arctic sea ice develops a growth of phytoplanktonic diatoms. The diatoms are found in a brine solution in microfissures between ice crystals on the underside of the ice. The chlorophyll content of this layer is 100 times more than that of the surrounding sea waters; this has led to a hypothesis that a considerable fraction of the primary production of the Arctic Sea may be carried out in sea ice, especially during the spring and early summer months.
RESUMO
In order to resolve the discrepancy between the measured and calculated 152Eu activity induced by the atomic bomb at Hiroshima, extremely low background gamma-ray spectrometry was performed for 17 granite samples collected from 134 m to more than 3 km from the hypocenter. Measurements agreed well with theoretical calculations based on DS02 up to 1.4 km from hypocenter.
Assuntos
Algoritmos , Európio/análise , Substâncias Explosivas/efeitos adversos , Nêutrons Rápidos/efeitos adversos , Guerra Nuclear , Dióxido de Silício/análise , Japão , Doses de Radiação , Espectrometria gama/métodosRESUMO
PURPOSE: Report of a case with retinal neovascularization developing in the setting of diabetic retinopathy despite complete posterior vitreous detachment (PVD). CASE REPORT: A 76-year-old man had had type II diabetes mellitus for more than 30 years. Weiss' ring was detected by direct and indirect ophthalmoscopy. PVD was thus considered to be complete. On the other hand, fluorescein angiography showed two areas of hyperfluorescence at the margin of the retinal nonperfusion area. CONCLUSIONS: The present case underscores the importance of periodic follow-up using fluorescein angiography, given the probability of retinal neovascularization development and proliferative changes for many years even in diabetic retinopathy associated with complete PVD.
Assuntos
Retinopatia Diabética/complicações , Neovascularização Retiniana/etiologia , Descolamento do Vítreo/etiologia , Idoso , Diabetes Mellitus Tipo 2/complicações , Retinopatia Diabética/diagnóstico , Angiofluoresceinografia , Humanos , Masculino , Neovascularização Retiniana/diagnóstico , Tomografia de Coerência Óptica , Ultrassonografia , Descolamento do Vítreo/diagnóstico por imagemRESUMO
Four types of 1-beta-D-arabinofuranosylcytosine (ara-C) conjugates with poly-L-glutamic acid (PLGA) or poly-N5-(2-hydroxyethyl)-L-glutamine (PHEG) were prepared in an attempt to enhance the efficacy of the drug in simple dosage schedules. The conjugates were made by linking ara-C to the carboxyl groups of PLGA directly at N-4 of ara-C (ara-C:PLGA) or indirectly through the 2-aminoethylphosphoryl or 6-aminohexylphosphoryl side chain which had been introduced to C-5' of ara-C, 1-[5'-(2-aminoethylphosphoryl)-beta-D-arabinofuranosyl]cytosine: PLGA [araCMP(C2):PLGA and 1-[5'-(6-aminohexylphosphoryl)-beta-D-arabinofuranosyl]cytosine:++ +PLGA, respectively, or made by converting the remaining carboxyl groups in the PLGA conjugates to the 2-hydroxyethylamide groups [ara-C:PHEG, ara-CMP(C2):PHEG, 1-[5'-(6-aminohexylphosphoryl)-beta-D-arabinofuranosyl]cytosine:++ +PHEG]. Studies in vitro showed that the conjugates had decreased cytotoxicity against L1210 cells when compared with that of ara-C. Studies in vivo showed that all of the conjugates, except ara-CMP(C2):PLGA, had a greater antitumor activity than did ara-C in L1210 tumor-bearing BALB/c X DBA/2 F, (hereafter called CD2F1) mice (inoculum, 1 X 10(5) cells i.p. on Day 0) which were treated by a single i.p. injection of either the conjugates or the control ara-C on Day 1. The largest antitumor activity [increased life span (ILS) 170%] was observed with a dosage of 50 mg (equivalent ara-C per kg) of ara-C:PHEG. When CD2F1 mice which had been inoculated i.p. with 1 X 10(5) L1210 cells were treated with an i.p. injection of 12.5 or 25 mg (equivalent ara-C per kg) of ara-C:PHEG daily for 5 days starting from Day 1, 2 of 5 mice survived more than 42 days, and the ILS of the remaining mice was 153 and 184%. The injections of 3.2 mg (equivalent ara-C per kg) of ara-C:PHEG showed a moderate antitumor activity with an ILS of 113% which was similar to the ILS (119%) found when unconjugated ara-C (400 mg/kg) was used to treat tumor-bearing mice. In in vitro release experiments, ara-C was released slowly from ara-C:PLGA at pH 7.4, and ara-CMP(C2):PLGA was chemically stable but cleaved by phosphodiesterase, acid phosphatase, and alkaline phosphatase to give mainly 1-beta-D-arabinofuranosylcytosine 5'-monophosphate.
Assuntos
Citarabina/uso terapêutico , Leucemia L1210/tratamento farmacológico , Peptídeos/uso terapêutico , Ácido Poliglutâmico/uso terapêutico , Animais , Sobrevivência Celular/efeitos dos fármacos , Leucemia L1210/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos DBA , Camundongos Endogâmicos , Espectrofotometria Ultravioleta , Relação Estrutura-AtividadeRESUMO
Changes in binding of dexamethasone (9 alpha-fluoro-11 beta, 17 alpha, 21-trihydroxy-16 alpha-methylpregna-1,4-diene-3,20-dione) to its receptors in regenerating rat liver after 70% hepatectomy were examined. Specific receptors for dexamethasone in the liver remnants of adrenalectomized rats decreased significantly during the period of DNA synthesis after 70% hepatectomy; then, they increased to above the control values between Days 4 and 7 after partial hepatectomy and subsequently returned to the control values. During the period of DNA synthesis, decreased binding was observed in partially hepatectomized rats with or without adrenals, but later enhanced binding was not prominent in rats with adrenals.
Assuntos
Dexametasona/metabolismo , Regeneração Hepática , Fígado/metabolismo , Receptores de Glucocorticoides/metabolismo , Receptores de Esteroides/metabolismo , Glândulas Suprarrenais/fisiologia , Adrenalectomia , Animais , Citosol/metabolismo , Hepatectomia , Cinética , Masculino , RatosRESUMO
The incidences of microsatellite instability (MSI) and underlying DNA mismatch repair (MMR) defects in pancreatic carcinogenesis have not been well established. We analyzed 100 sporadic and 3 hereditary pancreatic ductal adenocarcinomas for MSI, and high-frequency MSI (MSI-H) and low-frequency MSI (MSI-L) tumors were further analyzed for frameshift mutations of possible target genes and for promoter methylation and mutation of DNA MMR genes, including hMLH1, hMSH2, hMSH3, and hMSH6 genes. Among the 100 sporadic tumors, 13 (13%) were MSI-H, 13 (13%) were MSI-L, and 74 (74%) were microsatellite stable (MSS) tumors. All of the three hereditary tumors from hereditary nonpolyposis colorectal cancer (HNPCC) patients were MSI-H. MSI-H tumors were significantly associated with poor differentiation and the presence of wild-type K-RAS and p53 genes. Patients with MSI-H tumors had a significantly longer overall survival time than did those with MSI-L or MSS tumors (P = 0.0057). Frameshift mutations of hMSH3, hMLH3, BRCA-2, TGF-beta type II receptor, and BAX genes were detected in MSI-H tumors. Hypermethylation of the hMLH1 promoter was observed in 6 (46%) of the 13 sporadic MSI-H tumors but not in any of the 3 hereditary MSI-H tumors or 13 MSI-L tumors. All of the 3 HNPCC cases had germ-line hMLH1 mutation accompanied by loss of heterogeneity or other mutation in the tumor. Our results suggest that pancreatic carcinomas with MSI-H represent a distinctive oncogenic pathway because they exhibit peculiar clinical, pathological, and molecular characteristics. Our results also suggest the principal involvement of epigenetic or genetic inactivation of the hMLH1 gene in the pathogenesis of pancreatic carcinoma with MSI-H.
Assuntos
Carcinoma Ductal Pancreático/genética , Repetições de Microssatélites/genética , Neoplasias Pancreáticas/genética , Pareamento Incorreto de Bases/genética , Metilação de DNA , Reparo do DNA/genética , Feminino , Mutação da Fase de Leitura , Humanos , Masculino , Regiões Promotoras GenéticasRESUMO
Phosphatidylcholine and 2-aminoethylphosphonolipid, major membrane phospholipids in Tetrahymena, comprise 1,2-diacyl and 1-alkyl-2-acyl moieties, whereas phosphatidylethanolamine is solely in diacyl form. The overall fatty acid composition of phosphatidylcholine and 2-aminoethylphosphonolipid fractions from 15 degrees C-grown cells mainly consisted of linoleic (C18 : 2 delta 9,12) and gamma-linolenic (C18 : 3 delta 6,9,12) acids, except for the large amount of an usual fatty acid, cilienic acid (C18 : 2 delta 6,11) in 2-aminoethylphosphonolipids. When compared with 39.5 degrees C-grown cells, the 1-position of phosphatidylcholine and 2-aminoethylphosphonolipid from 15 degrees C-grown cells undergoes a large increase in palmitoleic (C16 : 1 delta 9) and gamma-linolenic acids with a corresponding decrease of myristic (C14 : 0) and palmitic (C16 : 0) acids. At the 2-position of 15 degrees C-grown cells, linoleic and gamma-linolenic acids in phosphatidylcholine, and cilienic and linoleic acids in 2-aminoethylphosphonolipid increase with a large decrease of palmitoleic acid in both phospholipids and of gamma-linolenic acid in 2-aminoethylphosphonolipid. There was quite a similarity in fatty acid composition between 1,2-diacylphosphatidylcholine and 1,2-diacyl-(2-aminoethyl)phosphonolipid in 39.5 degrees C- and 15 degrees C-grown cells. However, a marked increase of gamma-linolenic acid at the 1-position of 1,2-diacyl-phosphatidylcholine, and of linoleic acid at the 2-position of diacyl-aminoethylphosphonolipid was observed in 15 degrees C-grown cells. The 2-position of 1-alkyl-2-acyl-phosphatidylcholine and 1-alkyl-2-acyl-(2-aminoethyl)phosphonolipid was occupied mainly by unsaturated fatty acids. In 15 degrees C-grown cells, the sum of linoleic and gamma-linolenic acids accounted for 79.9% in 1-alkyl-2-acyl-phosphatidylcholine and 87.1% in 1-alkyl-2-acyl-(2-aminoethyl)phosphonolipid. These data support the hypothesis that 2-aminoethylphosphonolipid and phosphatidylcholine would play an important role as acceptors of polyunsaturated fatty acids (C18 : 2 delta 6,11, C18 : 2 delta 9,12 and C18: 3 delta 6,9,12) for temperature acclimation. Furthermore, changes in the ratio of diacyl- to alkyl-acylphosphatidylcholine may also be involved in thermal adaptation by regulating the number of fatty acid acceptor.
Assuntos
Ácidos Graxos/análise , Lipídeos de Membrana/metabolismo , Temperatura , Tetrahymena/metabolismo , Animais , Fosfatidilcolinas/análise , Fosfolipídeos/análiseRESUMO
[1-14-C]Palmitoyl-Co A was incubated with Tetrahymena microsomes containing the complete enzyme system for desaturation during various time periods. The level of [1-14C]palmitoleoyl-CoA increased to a maximum during the 1--3 min incubation time, while [1-14C]palmitoleic acid in the phospholipid reached a maximum level during 6--7 min incubation time. The radioactivity of [1-14C]palmitoleic acid in free fatty acid and the triglyceride fraction was not significantly observed upon 3 min incubation. Incubation of [1-14C]palmitoyl-CoA with microsomes in the absence of NADH produced [1-14C]palmitoyl lipid without desaturation. Radioactive palmitic acids in the microsomal lipids were not converted to palmitoleic acids after addition of NADH by the complete enzyme system. When microsomes prepared from cells labeled with [1-14C]palmitic acid or [1-14C]stearic acid were incubated alone in the presence of O2 and NADH, no significant increase in [1-14C]palmitoleic acid in the phospholipid was observed, wherease an increase in [1-14C]linoleic acid and gamma-[1-14C]linolenic acid did occur at the expense of [1-14C]oleic acid in the phospholipid. From these results it can be concluded that the enzyme involving desaturation of palmitic acid to palmitoleic acid requires palmitoyl-CoA as the substrate. However, the possibility of oleoyl and linoleoyl phospholipids being substrates in the desaturation of Tetrahymena microsomes was suggested.
Assuntos
Acil Coenzima A/metabolismo , Ácidos Graxos Dessaturases/metabolismo , Microssomos/metabolismo , Palmitoil Coenzima A/metabolismo , Tetrahymena/metabolismo , Ácidos Graxos Monoinsaturados , Ácidos Graxos Insaturados/metabolismo , Microssomos/enzimologia , Ácidos Palmíticos/metabolismoRESUMO
Palmitoyl-CoA desaturase activity in microsomes was increased up to about 4-fold within 2 h after temperature shift from 39.5 to 15 degrees C. Compared with control cells, cycloheximide-treated cells indicated no induction of palmitoyl-CoA desaturase by a decrease in temperature. The results suggest that temperature acclimation requires an increase in the level of the desaturase enzyme content.
Assuntos
Ácidos Graxos Dessaturases/metabolismo , Tetrahymena pyriformis/enzimologia , Adaptação Fisiológica , Cicloeximida/farmacologia , Ácidos Graxos Insaturados/metabolismo , Microssomos/enzimologia , Palmitoil Coenzima A/metabolismo , TemperaturaRESUMO
Phosphatidylethanolamine of 15 degrees C-grown Tetrahymena pyriformis (NT-I) cells contains more polyunsaturated fatty acids than 39.5 degrees C-grown cells. This increase in unsaturation is due to an increase in linoleic (C18 : 2) and linolenic (C18 : 3) acids, and a decrease in myristic (C14 : 0), palmitic (C16 : 0), palmitoleic (C16 : 1) and heptadecanoic (C17 : 0) acids. Compared with 39.5 degrees C-grown cells, the proportion of palmitic acid (C16 : 0) decreased in the 1-position as does at the 2-position in 15 degrees C-grown cells. On the contrary, there is a significant increase in linoleic (C18 : 2 delta 9, 12) and gamma-linolenic (gamma-C18 : 3) acids in the 1- and 2-positions, respectively. Phosphatidylethanolamine has been subfractionated into seven different diglyceride species. In 15 degrees C cells, the amounts of fractions 2 (1-linolenoyl-2-linoleoyl) and 3 (1-linolenoyl-2-palmitoleoyl, 1-linolenoyl-2-oleoyl) increased while there was a great decrease in subfraction 7 (1-myristoyl-2-palmitoleoyl, 1-palmitoyl-2-palmitoleoyl). Since subfractions 1 and 2 contain over 70% linoleic (C18 : 2) and linolenic (C18 : 3) acids, these fractions might be composed mainly of 1-linolenoyl-2-linolenoyl and 1-linolenoyl-2-linoleoyl molecular species at 15 degrees C. These data support evidence that phosphatidylethanolamine would play a principal role as an acceptor of acyl chains for temperature acclimation.