Trees on networks: resolving statistical patterns of phylogenetic similarities among interacting proteins

Background  

Phylogenies capture the evolutionary ancestry linking extant species. Correlations and similarities among a set of species are mediated by and need to be understood in terms of the phylogenic tree. In a similar way it has been argued that biological networks also induce correlations among sets of interacting genes or their protein products.     

The effect of different hyperglucagonemic states on monooxygenase activities and isozymic pattern of cytochrome P-450 in mouse

The continuous infusion of a low dose of glucagon (35 g/kg/d, for 5 d) constitutes, in view of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities , a reliable experimental model of hyperglucagonemia. By conjunction of monooxygenase assays and immunoquantitation of specific isozymes of cytochrome P-450, the actual inducing ability of glucagon has been shown and it might explain some of the modifications of the drug metabolizing system in diabetic mice. The isozymic pattern of cytochrome P-430 of liver microsomes from diabetic mice appears very different from that produced by classical inducers.     

南瓜雌蕊与自花及远缘花粉的相互作用

南瓜柱头表面经去垢剂、蛋白酶及Con A处理后花粉不能萌发或花粉管生长受阻,Con A能专一地与柱头表面结合。柱头块加入培养液可促进花粉萌发。不同的远缘花粉授粉后在雌蕊不同部位受阻。在成熟南瓜雌蕊提取液中检测到血凝活性,凝集素可能参与雌蕊对远缘花粉的抑制。     

Evaluation of isolated human hepatocytes

This preliminary study reports the functional capacities of freshly isolated human hepatocytes in regard to their energetic metabolism and monooxygenase activities. Incubated for 30 or 60 min, isolated cells maintain their membrane integrity, AIP and reduced glutathione content and redox potential estimated by means of lactate to pyruvate and ß-hydroxypyruvate to acetoacetate ratios. Three monooxygenase activities, supported by different isoenzymes of cytochrome P30 are determined by the accumulation of unconjugated metabolites: their relative magnitudes are similar to those observed in microsomes, indicating a good preservation of hydroxylase activities during cell isolation and incubation. Although incubations did not exceed 60 min, one can conclude that human hepatocytes maintain their viability and metabolic capacities after isolation and might be considered in transplantation process for the treatment of acute hepatic failure. Isolated human hepatocytes might be also used as a tool for studying biochemical and toxicological effects of a drug.     

Immunohistochemical localization of cytochrome P450 3A in human pulmonary carcinomas and normal bronchial tissue

The cytochrome P450 (CYP) enzymes metabolize drugs and other xenobiotics in liver and also in some extrahepatic tissues. We have studied the expression and localization of CYP3A in primary lung tumours and normal lung tissue from the same patients. Thirtytwo patients undergoing partial or total lung resection for therapy of primary pulmonary carcinoma were included in this study. Immunohistochemical staining for CYP3A was performed with a modification of the ABC technique. Eight of the 32 cases of primary pulmonary carcinoma showed expression of CYP3A. In 12 of the 32 cases of normal tissue, the seromucous glands were positive for CYP3A. The bronchial epithelium was positive for CYP3A in 11 cases. We observed no correlation between CYP3A expression in tumour tissue and that in seromucous glands or bronchial epithelium. We conclude that CYP3A is present in both normal and cancerous lung tissue. Our findings suggest, however, no co-expression of CYP3A in lung cancer.     

Anaerobic respiration of fumarate as a differential test betweenCampylobacter fetus andCampylobacter jejuni

The effect of formate and of various electron acceptors—fumarate, aspartate, or nitrate—on the growth of 36 catalase-producingCampylobacter strains was quantitatively investigated in a semisynthetic medium, under aerobic (5% oxygen, 10% carbon dioxide, 85% nitrogen) or anaerobic (10% carbon dioxide, 90% nitrogen) conditions. Under anaerobic conditions, 24 strains ofC. jejuni failed to grow, or grew poorly, in the presence of fumarate, whereas ten strains ofC. fetus subsp.fetus and two strains ofC. fetus subsp.venerealis grew abundantly, rather better than under aerobic conditions. The quantitative differences of growth yields were very significant between the two species with fumarate, but less pronounced with aspartate or nitrate. The activity of fumarate-reductase inC. fetus was substantiated by identification of relevant metabolites by gas liquid chromatography and by mass spectrometry. The anaerobic fumarate respiration in the genusCampylobacter has taxonomic implications.     

Interrelationships between plasma insulin-like growth factor-I (IGF-I) concentrations and plasma sex hormone levels in the growing male guinea-pig.

The aim of the present study was to determine the influence of androgens on Insulin-like Growth Factor-I (IGF-I) release at puberty in male guinea-pigs. After the animals were orchiectomised (CX) or sham-operated (SO) at the end of weaning, plasma testosterone (T), dihydrotestosterone (DHT) and IGF-I levels were measured by RIA at the 4th (W4), 8th (W8) and 12th (W12) week after delivery. Body weight (BW) was recorded before sampling at each stage of the experiment. Body growth was maximal between W4 and W8 for both SO (+97%) and CX (+84%). However SO were heavier than CX at W8 and W12. In SO, a surge of plasma IGF-I levels was observed between W4 and W8, concomitantly to the increase of androgen levels (IGF-I: +86%, P less than 0.01; T: +190%, P less than 0.001; DHT: +18%; P less than 0.01). Significant correlations between IGF-I, T, DHT and BW were found only from W4 to W8 but not from W8 to W12. In CX, IGF-I levels were higher than in SO at W4 (+72%, P less than 0.01) and at W12 (+39%, P less than 0.01). A surge of IGF-I levels (+47%, P less than 0.01) was also observed but was delayed compared to SO (between W8 and W12 vs W4 and W8). BW and IGF-I levels were significantly correlated during this period. Because the surge of IGF-I levels may occur even in absence of gonads, these results give evidence that the increases in IGF-I and androgens at puberty were independent in guinea-pigs during this period.(ABSTRACT TRUNCATED AT 250 WORDS)