KLF9 regulates hepatic lipid metabolism via inducing CD36 expression / 生理学报

The development of nonalcoholic fatty liver disease (NAFLD) is closely related to the fatty acid (FA) uptake. This study aimed to investigate the effect of Krüppel-like factor 9 (KLF9) on CD36 (typical fatty acid translocase), hepatocellular lipid metabolism as well as the development and progression of nonalcoholic fatty liver. High-fat diet-induced obese C57BL/6J mice and db/db mice were used to test the expression levels of Klf9 and Cd36 in the livers. The primary hepatocytes were isolated from C57BL/6J mice, treated with Ad-GFP, Ad-Klf9, Ad-shCtrl or Ad-shKlf9, and then incubated with oleic acid and palmitic acid for 24 h. Liver-specific knockout of Klf9 mice were established. The protein levels and relative mRNA levels were examined by Western blot and real-time PCR, respectively. Triglyceride content was determined by using an assay kit. Lipid content was determined by Oil Red O staining. The results showed that: (1) Klf9 expression levels were increased in the livers of high-fat diet-induced obese mice and db/db mice, compared to their respective control mice. (2) Adenovirus-mediated overexpression of Klf9 in primary hepatocytes increased Cd36 expression and cellular triglyceride contents. (3) In contrast, adenovirus-mediated knockdown of Klf9 expression in primary hepatocytes by Ad-shKlf9 decreased Cd36 expression and cellular triglyceride contents. (4) Finally, Klf9 deficiency decreased liver Cd36 expression and alleviated fatty liver phenotype of high-fat diet-induced obese mice. These results suggest that KLF9 can regulate hepatic lipid metabolism and development of NAFLD by promoting the expression of CD36.

Production and characterization of an extracellular lipase from Candida guilliermondii

Extracellular lipases from the endophytic yeast Candida guilliermondii isolated from castor leaves (Ricinus communis L.) were produced using low-cost raw materials such as agro-industrial residues and applying them in the esterification of oleic acid for evaluating their potential use in biodiesel production. After partial purification using ammonium sulfate, the enzyme was characterized and presented higher activity (26.8 ± 1.5 U mL-1) in the presence of 5 mmol L-1 NaCl at 30 ºC and pH 6.5. The production through submerged fermentation was formerly performed in 150 mL erlenmeyer flasks and, once the enzyme production was verified, assays in a 14 L bioreactor were conducted, obtaining 18 ± 1.4 U mL-1. The produced enzyme was applied in the oleic acid esterification under different solvents: hexane, cyclohexane or cyclohexanone) and different acid:alcohol molar ratios. Higher ester conversion rate (81%) was obtained using hexane and the molar ratio of 1:9 was the best conditions using methanol. The results suggest the potential for development of endophytic yeast in the production of biocatalyst through submerged fermentation using agroindustrial residues as culture medium.

Sodium azide mutagenesis resulted in a peanut plant with elevated oleate content

Screening of peanut seeds resulting from 0.39 percent sodium azide treatment with NIRS calibration equation for bulk seed samples identified a plant with more than 60 percent oleate. Oleate content in individual seeds of the plant, as predicted by NIRS calibration equation for intact single peanut seeds, ranged from 50.05 percent ~ 68.69 percent. Three seeds with >60 percent oleate thus identified were further confirmed by gas chromatography. Multiple sequence alignments of the FAD2B gene from Huayu 22 (wild type) and peanut seeds with elevated oleate (mutant type) revealed a C281T transition in the coding region causing an I94T substitution in the oleoyl-PC desaturase, which may be responsible for reduction in the enzyme activity.

Kinetics of fatty acid binding ability of glycated human serum albumin.

Kinetics of fatty acid binding ability of glycated human serum albumin (HSA) were investigated by fluorescent displacement technique with 1-anilino-8-naphtharene sulphonic acid (ANS method), and photometric detection of nonesterified-fatty-acid (NEFA method). Changing of binding affinities of glycated HSA toward oleic acid, linoleic acid, lauric acid, and caproic acid, were not observed by the ANS method. However, decreases of bind-ing capacities after 55 days glycation were confirmed by the NEFA method in comparison to control HSA. The decrease in binding affinities was: oleic acid (84%), linoleic acid (84%), lauric acid (87%), and caproic acid (90%), respectively. The decreases were consistent with decrease of the intact lysine residues in glycated HSA. The present observation indicates that HSA promptly loses its binding ability to fatty acid as soon as the lysine residues at fatty acid binding sites are glycated.

Staphylococcus warneri BW 94--a new source of lipase.

Staphylococcus isolated from a common Indian sweet viz. basundi was tested for its ability to produce lipase. The colorless zone of hydrolysis around the colony grown on Baird Parker agar containing egg yolk produced extracellular lipase. Colony morphology, coagulase production, haemolysis, acid production in carbohydrate medium and enzyme activity studies showed that the organism was Staphylococcus warneri. Growth of S. warneri was obtained after 11 hr at 37 degrees C, pH 7.5, while the maximum production of lipase was obtained at 30 degrees C at pH 6.5 after 9 hr of incubation. Agitation did not increase lipase production. A sudden fall in the activity of lipase was noted after 11 hr. Addition of sucrose which is a growth stimulant for Staphylococcus, did not stimulate production of lipase by these organisms. Also, addition of oleic acid, Tween 80 or ethanol did not stimulate formation of lipase.

Estudo da captaçäo de ácido graxo de cadeia longa pela mucosa intestinal humana in vitro / Study of the human intestinal cellular uptake of long-chain fatty acids in vitro

Estudos recentes têm sugerido a existência de transporte de AGCL mediado por carregador, em vários tipos de células animais. O objetivo deste trabalho foi investigar a presença de transporte de AGCL, mediado por carregador, na mucosa intestinal humana. Para isto, foram retirados fragmentos de biópsia da segunda porçäo do intestino delgado de 140 pacientes submetidos à endoscopia digestiva alta. Para avaliar o tempo de captaçäo dos AGCL, os fragmentos de biópsia foram incubados em diferentes tempos, mantendo-se fixa a proporçäo de (üH) ácido oléico/albumina. Após extraçäo, os lipídeos intracelulares foram separados por cromatografia de camada fina. Para cálculo da cinética de captaçäo do (üH) ácido graxo livre, as amostras foram incubadas durante 5min, em meio de cultura a 37ºC, contendo (üH) ácido oléico e albumina em diversas proporções. A influência da temperatura no sistema foi estudada incubando-se os fragmentos de biópsia, de um mesmo paciente, a 4ºC e a 37ºC. Para inibir a proteína transportadora foi adicionado phlorentin em diferentes concentrações ao meio de cultura, durante 5min, comparando-se com fragmentos de biópsia do mesmo paciente incubado sem o inibidor. O estudo da cinética do transporte, mostrou uma curva de saturaçäo compatível com o modelo de Michaelis-Menten (Vmax=0,5ñ0,1) nmoles/mg/min, Km-6,27ñ8µM). Aos 5 min de incubaçäo, 95 por cento do (üH) ácido oléico encontrava-se ainda na forma de ácido graxo livre, mostrando que neste tempo houve apenas transporte. Aos 21 min de incubaçäo ocorreu queda da captaçäo, o que pode significar exportaçäo de lipoproteínas. A diminuiçäo da captaçäo (78 por cento) a 4ºC, em 5min, demonstra a existência de mecanismo dependente de energia. A presença de phlorentin no meio de cultura teve efeito variável sobre a captaçäo de (üH) ácido oléico, o que pode decorrer de sua açäo bivalente tanto na proteína como nos lipídeos da membrana plasmática. Conclui-se que o transporte de ácido oléico, na mucosa intestinal humana, ocorre tanto por difusäo simples como por mediado por proteína transportadora dependente de energia

Influencia del ácido oleico sobre la actividad angiotensinasa de astroglía cortical de rata / Influence of oleic acid in the angiotensinase activity in the cortical astroglia in rats

Objetivo. Las dietas elevadas en grasa están asociada con el desarrollo de enfermedades cerebrovasculares de distinto tipo. Distintos estudios epidemiológicos ha demostrado que la población de los países mediterráneos tienen menor porcentaje de enfermedades cerebro vasculares que la población del norte de Europa o de Estados Unidos de Norteamérica. En los países mediterráneos, la dieta habitual contiene una gran proporción de ácidos grasos monoinsaturados, mientras que en los países mas industrializados, el componente graso está constituido principalmente por grasas saturadas. Las aminopeptidasas (AP) son especialmente importantes por que están implicadas en el metabolismo y regulación de hormonas circulantes y péptidos biológicamente activos de numerosos tejidos. Algunas aminopeptidasas están relacionadas con el metabolismo de las angiotensinas en el sistema renina-angiotensina (RAS), y por tanto participan en la regulación de la presión sanguínea, tanto a nivel sistémico como local. El sistema nervioso es, probablemente, uno de los órganos mas sensibles a las alteraciones de la presión arterial. El presente trabajo se ha diseñado para estudiar el comportamiento de la actividad angiotensinasa en astrocitos de corteza frontal de rata, cultivados en presencia de distintas concentraciones de ácido oleico en el medio de cultivo. Material y métodos. La actividad angiotensinasa (aspartato-glutamato-aminopeptidasa) se analizó en cultivos primarios de astrocitos de rata, utilizando b -naftilamidas como sustratos. Resultados y conclusiones. Las disminuciones observadas en la actividad aminopeptidasa ponen de manifiesto la posible influencia del ácido oleico sobre algunos de los factores implicados en la regulación del flujo sanguíneo local o la homeostasis de líquidos y electrólitos locales en el sistema nervioso. Se discute que esta acción puede ser debida a la modificación de los procesos de comunicación intercelular mediados por uniones de tipo GAP o bien, a la modulación de los sistemas de comunicación intracelular mediados por el fosfatidilinositol y posterior activación de la proteinkinasa C, entre otros