Studies on the metabolism of unsaturated fatty acids. XVI. Purification and general properties of 2,4-dienoyl-CoA reductase from Candida lipolytica

2,4-Dienoyl-CoA reductase has been purified to homogeneity from Candida lipolytica cultivated in the presence of linoleic acid. The native enzyme had a molecular weight close to 360,000 as estimated by gel filtration on Sepharose CL-4B, whereas the subunit molecular weight estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 33,000. The purified 2,4-dienoyl-CoA reductase from C. lipolytica gave a single precipitin line with antibodies raised against the purified enzyme from C. lipolytica. The general properties of the 2,4-dienyl-CoA reductase from C. lipolytica were examined. The enzyme had optimal pH at 6.5 and was inactivated by heat treatment at 50 degrees C for 10 min. trans-2,trans-4-Octadienoyl-CoA was the most active substrate of the dienoyl-CoA esters examined.     

Relationship between enhancement of morphine analgesia and inhibition of enkephalinase by 2S, 3R 3-amino-2-hydroxy-4-phenylbutanoic acid derivatives

The effects of nineteen AHPA* derivatives were examined on morphine analgesia by tail-flick test in rats and on enkephalinase inhibition which was based on the formation of tyrosyl-glycyl-glycine from met-enkephalin. The correlation between the enhancement of morphine analgesia in vivo and enkephalinase inhibition in vitro was analyzed. The different analogs varied considerably in the degree of enhancement of morphine analgesia and inhibition of enkephalinase. A close relationship between enkephalinase inhibition expressed by IC50 in vitro and enhancement of morphine analgesia in vivo was observed in thirteen out of nineteen AHPA derivatives examined. One of other six AHPA derivatives which showed weak effectiveness in potentiating on morphine analgesia but was highly potent as an enkephalinase inhibitor, caused potent analgesic action when it was applied intracisternally indicating poor penetration of the blood brain barrier. The possibility was discussed that some of other compounds excluded from the linear relationship might act on other enkephalin degrading enzymes such as aminopeptidase.     

Plasma B-type Natriuretic Peptide as a Predictor of Cardiovascular Events in Subjects with Atrial Fibrillation: A Community-Based Study

Objectives

Atrial fibrillation (AF) is a significant public health issue due to its high prevalence in the general population, and is associated with an increased risk of cardiovascular (CV) events including systemic thrombo-embolism, heart failure, and coronary artery disease. The relationship between plasma B-type natriuretic peptide (BNP) and CV risk in real world AF subjects remains unknown.

Methods

The subject of the study (n = 228; mean age = 69 years) was unselected individuals with AF in a community-based population (n = 15,394; AF prevalence rate = 1.5%). The CV event free rate within each BNP tertile was estimated, and Cox regression analysis was performed to examine the relative risk of the onset of CV events among the tertiles. The prognostic ability of BNP was compared to an established risk score for embolic events (CHADS2 score). In addition, to determine the usefulness of BNP as a predictor in addition to CHADS2 score, we calculated Net Reclassification Improvement (NRI) and Integrated Discrimination Improvement (IDI) indices.

Results

During the follow-up period 58 subjects experienced CV events (52 per 1,000 person-years). The event-free ratio was significantly lower in the highest tertile (p < 0.02). After adjustment for established CV risk factors, the hazard ratio (HR) of the highest tertile was significantly higher than that of the lowest tertile (HR = 2.38; p < 0.02). The predictive abilities of plasma BNP in terms of sensitivity and specificity for general CV events were comparable to those of CHADS2 score. Adding BNP to the CHADS2 score only model improved the NRI (0.319; p < 0.05) and the IDI (0.046; p < 0.05).

Conclusion

Plasma BNP is a valuable biomarker both singly or in combination with an established scoring system for assessing general CV risk including stroke, heart failure and acute coronary syndrome in real-world AF subjects.     

Defense response of a pepper cultivar cv. Sy-2 is induced at temperatures below 24°C

Temperature is one of the most important environmental factors that influence plant growth and development. Recent studies imply that plants show various responses to non-extreme ambient temperatures. Previously, we have found that a pepper cultivar cv. Sy-2 (Capsicum chinense) shows developmental defects at temperatures below 24°C. In this study, to gain new insights into the temperature sensitivity of cv. Sy-2, temperature-sensitive genes were screened using microarray techniques. At restrictive temperature of 20°C, almost one-fourth of the 411 up-regulated genes were defense related or predicted to be defense related. Further expression analyses of several defense-related genes showed that defense-related genes in cv. Sy-2 were constitutively expressed at temperatures below 24°C. Moreover, accumulation of high level of salicylic acid (SA) in cv. Sy-2 grown at 20°C suggests that the defense response is activated in the absence of pathogens. To confirm that the defense response is induced in cv. Sy-2 below 24°C, we evaluated the resistance to biotrophic bacterial pathogen Xanthomonas campestris pv. vesicatoria and necrotrophic fungal pathogen Cercospora capsici. Cv. Sy-2 showed enhanced resistance to X. campestris pv. vesicatoria, but not to C. capsici.     

Medium-term <Emphasis Type="Italic">in vitro</Emphasis> conservation of virus-free parthenocarpic tomato plants

Infection of field-maintained parthenocarpic Solanum lycopersicum L. (tomato) plants with Tomato yellow leaf curl virus provided the motivation to preserve the germplasm by in vitro methods. In this study, a method for medium-term in vitro conservation of parthenocarpic tomato plants was established. As a preliminary study, the non-parthenocarpic tomato ‘Momotaro’ was used to obtain a number of uniform explants for vegetative propagation under aseptic conditions at 23°C. The modification of sucrose or mannitol concentrations in the medium alone was insufficient for the slow-growth storage of shoot cultures. In contrast, temperature had a considerable effect on the time of conservation. ‘Momotaro’ shoot cultures were pre-cultured with Murashige and Skoog (MS) medium supplemented with 2% (w/v) sucrose at 23°C for 6 d for rooting and were then stored at 10°C for further conservation. When maintained at 10°C, only 27% of the shoot cultures needed subculture even after 3 mo, whereas 100% of plants needed subculturing after approximately 2 wk., when conserved at 23°C. When the same method was used with parthenocarpic tomatoes, plants were successfully conserved at 10°C without subculture for approximately 9 mo. Moreover, field performance and genetic stability of the stored tomato plants were assessed. This newly developed method allows for easy and efficient medium-term in vitro conservation to maintain virus-free parthenocarpic tomato plants.     

Studies on the metabolism of unsaturated fatty acids. XV. Purification and properties of 2,4-dienoyl-CoA reductase from rat liver peroxisomes

Peroxisomal 2,4-dienoyl-CoA reductase was purified from rat liver to homogeneity. The subunit molecular weight of 33,000 was determined by sodium dodecyl sulfatepolyacrylamide gel electrophoresis. The native molecular weight close to 120,000 was estimated by gel filtration on Sephacryl S-300 Superfine. trans-2, trans-4-Decadienoyl-CoA was the most active substrate among the dienoyl-CoA's of various chain lengths. The total activity of peroxisomal 2,4-dienoyl-CoA reductase exceeded that of the mitochondrial one even in the livers of rats fed with a standard diet. Furthermore both reductases were remarkably and coordinately induced in the livers of clofibrate-treated rats.