RESUMEN
Cruciform structures are preferential targets for many architectural and regulatory proteins, as well as a number of DNA binding proteins with weak sequence specificity. Some of these proteins are also capable of inducing the formation of cruciform structures upon DNA binding. In this paper we analyzed the amino acid composition of eighteen cruciform binding proteins of Homo sapiens. Comparison with general amino acid frequencies in all human proteins revealed unique differences, with notable enrichment for lysine and serine and/or depletion for alanine, glycine, glutamine, arginine, tyrosine and tryptophan residues. Based on bootstrap resampling and fuzzy cluster analysis, multiple molecular mechanisms of interaction with cruciform DNA structures could be suggested, including those involved in DNA repair, transcription and chromatin regulation. The proteins DEK, HMGB1 and TOP1 in particular formed a very distinctive group. Nonetheless, a strong interaction network connecting nearly all the cruciform binding proteins studied was demonstrated. Data reported here will be very useful for future prediction of new cruciform binding proteins or even construction of predictive tool/web-based application.
Asunto(s)
Aminoácidos/química , Proteínas de Unión al ADN/química , Cromatina , Proteínas Cromosómicas no Histona/química , ADN-Topoisomerasas de Tipo I/química , Proteína HMGB1/química , Humanos , Conformación de Ácido Nucleico , Proteínas Oncogénicas/química , Proteínas de Unión a Poli-ADP-Ribosa/químicaAsunto(s)
Crimen , Perros , Incendios , Animales , Cromatografía de Gases , Sensibilidad y EspecificidadRESUMEN
In Syrian hamsters, a diet with 44% of the calories being fat and containing 52 mg cholesterol (C)/100 g induced an accumulation of blood plasma and liver C and triacylglycerol (TG). In these animals, we studied the effect of dried whole mushroom (Pleurotus ostreatus, 2% in the diet, 6-mo experiment) and ethanol-insoluble residue and structurally defined fungal polysaccharide, both isolated from the mushroom (in both cases, 4% in the diet, 2-mo experiments) on C and TG concentration in serum and liver. Whole mushroom effectively retarded the increase in C and TG in both serum and liver throughout the experiment. The mushroom also reduced the content of all lipids in lipoproteins with densities of less than 1.006 to less than 1.063 g/ml. Very-low-density lipoproteins played a substantial role in the decrease (65-80%) in serum lipids. As a result, the lipoprotein concentration of the specified density classes was reduced by 45-60%, and the concentration of the serum lipoprotein pool was reduced by 40%. Neither the chemical composition of high-density lipoproteins nor their serum concentration was affected by the mushroom. Ethanol-insoluble mushroom residue did not significantly affect serum lipid levels, but it reduced liver TG content. Fungal polysaccharide lowered the C content in serum and liver.
Asunto(s)
Dieta , Hiperlipoproteinemias/metabolismo , Metabolismo de los Lípidos , Hígado/metabolismo , Polyporaceae , Polisacáridos/farmacología , Animales , Colesterol/sangre , Colesterol/metabolismo , Cricetinae , Lípidos/sangre , Lipoproteínas/sangre , Lipoproteínas VLDL/sangre , Hígado/efectos de los fármacos , Masculino , Mesocricetus , Polyporaceae/química , Triglicéridos/sangre , Triglicéridos/metabolismoRESUMEN
The authors studied 1-14C-palmitate metabolism in rat muscle, renal cortex and liver incubated with synthetic hippurate in vitro (1 mmol/l). a) Hippurate did not affect 1-14C-palmitate uptake and utilization in the muscle (hemidiaphragm). b) In the renal cortex it stimulated only the incorporation into total lipids and from the individual lipid fractions into mono- and diglycerides and free fatty acids (FFA). c) In the liver it stimulated the uptake, oxidation to 14CO2 and incorporation into total lipids and, out of the individual lipid fractions, into phospholipids, triacylglycerols and free fatty acids. d) Hippurate already had a significant effect in the concentration of 0.5 mmol/l, i.e. during the development of the disturbance and not just as a supplementary factor in advanced renal insufficiency. It is concluded that, by interfering with fatty acid metabolism, the hippurate present in the serum of patients with renal insufficiency plays an active role in the development of dyslipoproteinaemia in such patients.
Asunto(s)
Hipuratos/farmacología , Corteza Renal/metabolismo , Hígado/metabolismo , Músculos/metabolismo , Palmitatos/metabolismo , Animales , Relación Dosis-Respuesta a Droga , Masculino , Oxidación-Reducción , Ratas , Ratas EndogámicasRESUMEN
The effect of two dehydrated apple products (10% in diet)--apple pulp (crude fibre 3.5%, pectin 1.4%) and apple pomaces (crude fibre 13.5%, pectin 7%)--on the serum and liver lipids of growing Syrian male hamsters were studied. The animals were fed a natural diet (38% of energy substituted by milk fat; the diet contains 53 mg of cholesterol (CH) per 100 g) which resulted in an accumulation of CH and triacylglycerols (TG) in the serum as well as in the liver, and CH-rich very low density lipoproteins (VLDL) in the circulation. After two months both apple products decreased the levels of CH and TG in serum (by 40-70%) and the content of CH in VLDL with similar efficiency. Both products reduced CH content in the liver, and the apple pulp also decreased TG content. Up to the 6th month the apple pulp studied suppresses accumulation of CH and TG in both the serum and the liver. A complete analysis of lipoproteins of main density class at the time showed that the decrease of serum CH and TG to a decisive extent is due to the decrease of their concentration in VLDL (by more than 50%). Therefore, the concentration of VLDL and the whole lipoprotein pool decreased by 50%. The apple pulp doubled the amount of CH transported by HDL. Three months after the replacement of butter in the diet by corn germ oil the CH and TG levels in the serum and TG also in the liver decreased to the physiological level.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Colesterol/análisis , Frutas , Hígado/química , Triglicéridos/análisis , Animales , Colesterol/sangre , HDL-Colesterol/análisis , VLDL-Colesterol/análisis , Cricetinae , Desecación , Conservación de Alimentos , Lipoproteínas/análisis , Masculino , Mesocricetus , Triglicéridos/sangreRESUMEN
Golden hamsters with alimentary hyperlipoproteinaemia (fed on a diet in which 44% of the energy was accounted for by fats, 52 mg cholesterol (CH)/100 g) were given apple pulp (10% of the diet) for six months. From the end of the first month up to the end of the experiment, elevation of serum CH, triacylglycerol (TG) and phospholipid (PL) levels and CH and TG accumulation in the liver were effectively inhibited. At the close of the experiment, hyperlipoproteinaemia was characterized by an increase in the amount of very low density lipoproteins (VLDL), which carried 60-80% of all circulating lipids, accounted for over 70% of the total lipoprotein pool and transported almost 60% of the serum CH (high density lipoproteins--HDL--only 16%). The apple diet markedly reduced (by 50-80%) the amount of all lipids in the lipoproteins within density limits of 1,006-1,063 kg/m3 and lowered the total lipid concentration in these density classes and in the lipoprotein pool as a whole (by 50%). The proportion of the individual lipoprotein classes in the lipoprotein pool was not significantly affected. The apple diet did not affect either the chemical composition of HDL or their participation in the lipoprotein pool, but raised the proportion of serum CH transported in this lipoprotein class. Neither the lipoprotein lipase activity of the adipose tissue nor lecithin:cholesterol acyltransferase activity were influenced by the apple diet.
Asunto(s)
Frutas , Hiperlipoproteinemias/tratamiento farmacológico , Tejido Adiposo/enzimología , Animales , Peso Corporal , Colesterol/metabolismo , Cricetinae , Lipoproteína Lipasa/biosíntesis , Lipoproteínas/análisis , Masculino , Fosfatidilcolina-Esterol O-Aciltransferasa/biosíntesis , Fosfolípidos/metabolismo , Triglicéridos/metabolismoAsunto(s)
Enfermedades Gastrointestinales/cirugía , Periodo Posoperatorio , Procedimientos Quirúrgicos Operativos , Equilibrio Hidroelectrolítico , Adolescente , Adulto , Enfermedades Gastrointestinales/sangre , Enfermedades Gastrointestinales/orina , Humanos , Riñón/fisiopatología , Persona de Mediana Edad , Concentración Osmolar , Cuidados PosoperatoriosRESUMEN
Albumin metabolism was followed in 7 patients suffering from benign gastric diseases. The study was performed using human serum albumin-125 I before gastric surgery and after operation. The total albumin pool decreased after the operation by about 15%. The decrease in extravascular albumin pool was stronger (by about 19%) than the decrease in intravascular albumin pool (at about 11%). The causes of changes in albumin metabolism after surgery are discussed.
Asunto(s)
Albúminas/metabolismo , Gastrectomía , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Albúmina Sérica/análisis , Albúmina Sérica RadioyodadaRESUMEN
The authors studied the effect of chronic physical exercise (running in a rotating drum at 850 m/hour, 5 times a week for 16 weeks) on the size of the cholesterol body pools and on cholesterol kinetics in adult male Wistar rats fed on a standard diet either ad libitum or 2 hours daily [33 weeks]. These data were obtained by mathematical analysis of the curve expressing the correlation of specific plasma cholesterol activity to time after a single dose of cholesterol-4-14C. Chronic physical stress and infrequent feeding, as separate experimental stimuli, both caused cholesterol to shift from the blood plasma at a higher rate and reduced the size of one or both cholesterol body pools (with quick or slow turnover, pools A and B). Physical exercise also reduced fractional cholesterol turnover in pool A. When the two stimuli were combined, i.e. in infrequently fed and chronically stressed rats, the rate of the cholesterol shift from the blood plasma slowed down, the total and irreversible shift of cholesterol from pool A diminished and the production rate in this pool also fell.
Asunto(s)
Colesterol/sangre , Ingestión de Alimentos , Esfuerzo Físico , Animales , Peso Corporal , Cinética , Masculino , RatasAsunto(s)
Ingestión de Alimentos , Lípidos/biosíntesis , Esfuerzo Físico , Animales , Masculino , Ratas , Factores de TiempoRESUMEN
The authors studied interference by the inhibitor of glucose utilization with free fatty acid (FFA) metabolism in rat kidney cortex slices. They found that FFA uptake by the kidneys, their incorporation into triglycerides (TG) and oxidation to 14CO2 were lower when the inhibitor was present in the incubation medium. The findings show that the inhibitor, as well as inhibiting glucose utilization in various tissues, interferes directly with fat metabolism.
Asunto(s)
Ácidos Grasos no Esterificados/metabolismo , Glucosa/antagonistas & inhibidores , Corteza Renal/metabolismo , Fallo Renal Crónico/metabolismo , Animales , Metabolismo de los Hidratos de Carbono , Técnicas In Vitro , Masculino , Oxidación-Reducción , RatasRESUMEN
The authors studied the effect of glucose on the uptake and utilization of palmitate 1 14C by rat kidney cortex slices. They found that its inhibitory effect on free fatty acid (FFA) uptake was caused by inhibition of the incorporation of 1 14C-labelled palmitate into the total lipids and FFA and by reduced oxidation to 14CO2. Glucose has a regulative function in the utilization of FFA by the kidneys.