Comparison of Zinc Reduction with Platinum Reduction for Analysis of Deuterium‐Enriched Water Samples for the Doubly Labeled Water Technique

Objective: Isotope ratio mass spectrometry of hydrogen and oxygen is frequently used to determine total energy expenditure (TEE) using doubly labeled water. Conventionally, hydrogen isotope ratio is determined in hydrogen gas generated from water samples using zinc reduction. We compare this with a new automated platinum method to determine the ratios of hydrogen isotopes in deuterium‐enriched water samples. Research Methods and Procedures: The platinum method of sample preparation was compared with the zinc method in three ways: analytical variation in deuterium enrichment (within sample; n = 51), analytical variation in TEE estimates (within sample set; n = 10), and level of agreement of TEE estimates between both methods (n = 14). Results: For the zinc method, the standard deviation for multiple sets of triplicate ²H₂O sample analysis was ±4.36‰ and ±2.07‰ for platinum. The correlation between TEE estimates when sample sets were analyzed in duplicate was r = 0.89 for zinc and r = 0.83 for platinum. The intercept and slope of the regression line were significantly different from the line of identity for duplicate TEE estimates by zinc but were not different from the line of identity for platinum. After correction for the intra‐assay variation of each method, the correlation between zinc and platinum for TEE was 0.77, and the intercept, but not the slope, of the regression was significantly different from the line of identity. The mean difference between the zinc method and the platinum method was 56 kcal/day, and the 95% confidence interval was ?438 to 550 kcal/day. Discussion: These data suggest that the platinum method is at least as reliable as the zinc method as a sample preparation technique for isotope ratio mass spectrometry of deuterium‐enriched water samples. The platinum method is also less costly and less labor‐intensive than the zinc method.     

Leaf characteristics and optical properties of different woody species

 Light partition has been examined and evaluated on five woody species (Olea europaea, Ficus carica, Pittosporum tobira, Hedera helix maculata, Persica vulgaris) in relation to their leaf morpho-histological characteristics, water and chlorophyll contents. Leaf parameters and optical properties (reflectance, transmittance, absorbance) in PAR, FR and NIR wavebands (400–1100 nm) were preliminarily submitted to a canonical correlation analysis where lamina thickness and water content showed a leading role in determining all the optical properties, while chlorophyll, influential in the PAR region, was remarkably effective only in an extreme pigment situation when green and albino patches of ivy leaves were compared. Transmittance appeared inversely related to lamina thickness in accordance with the Lambert Beer law. Significant correlations were found also between mesophyll water content and both transmittance (positive) and reflectance (negative). Olive leaves showed peculiar optical patterns because of the dense and continuous trichome layer on their abaxial surface. Received: 3 January 1997 / Accepted: 5 May 1997     

Mediatietherapie bij ouderen met een persoonlijkheidsstoornis: Een verpleegkundige benadering

Behavioural counselling by nurses can enhance quality of life in elderly with a personality disorder. Although nurses have a crucial role in day-to-day treatment, there is a lack of evidence-based approaches. Based on the cognitive therapy, the treatment protocol Cognitive Model for Behavioural Interventions (CoMBI) provides an alternative nursing approach for personality disorders.     

Nutrients and disturbance history in two Plantago species: maternal effects as a clue for observed dichotomy between resprouting and seeding strategies

We assessed the role of nutrients and disturbance experienced by mothers (maternal effects) in the growth of progeny in a pot experiment using two Plantago species. Photosynthetic capacity, biomass allocation and fecundity were measured. Offspring of plants grown in nutrient poor conditions produced more leaves, spikes and longer leaves and in case of P. lanceolata , they had also higher photosynthetic capacity. The progeny of P. media mothers that had resprouted after disturbance was favored in nutrient poor conditions whereas the progeny of undisturbed plants was favored in nutrient rich conditions.
This study demonstrates that maternal effects may play a role in the success of either a seeding or a resprouting strategy in environments with different nutrient availability. Moreover, we showed that alteration of photosynthetic capacity, even during adult stages, is a mechanism through which maternal plants may impact their progeny.     

Deglutarylation of glutaryl-CoA dehydrogenase by deacylating enzyme SIRT5 promotes lysine oxidation in mice

A wide range of protein acyl modifications has been identified on enzymes across various metabolic processes; however, the impact of these modifications remains poorly understood. Protein glutarylation is a recently identified modification that can be nonenzymatically driven by glutaryl-CoA. In mammalian systems, this unique metabolite is only produced in the lysine and tryptophan oxidative pathways. To better understand the biology of protein glutarylation, we studied the relationship between enzymes within the lysine/tryptophan catabolic pathways, protein glutarylation, and regulation by the deglutarylating enzyme sirtuin 5 (SIRT5). Here, we identify glutarylation on the lysine oxidation pathway enzyme glutaryl-CoA dehydrogenase (GCDH) and show increased GCDH glutarylation when glutaryl-CoA production is stimulated by lysine catabolism. Our data reveal that glutarylation of GCDH impacts its function, ultimately decreasing lysine oxidation. We also demonstrate the ability of SIRT5 to deglutarylate GCDH, restoring its enzymatic activity. Finally, metabolomic and bioinformatic analyses indicate an expanded role for SIRT5 in regulating amino acid metabolism. Together, these data support a feedback loop model within the lysine/tryptophan oxidation pathway in which glutaryl-CoA is produced, in turn inhibiting GCDH function via glutaryl modification of GCDH lysine residues and can be relieved by SIRT5 deacylation activity.     

Dissociation by NH4Cl treatment of the enzymic activities of glutamine synthetase II from Rhizobium leguminosarum biovar viceae.

Glutamine synthetase II (GSII) was purified to homogeneity from Rhizobium leguminosarum biovar viceae and characterized. The sequence of 26 amino acid residues from the amino-terminal end of the protein showed high similarity with the sequence of GSII from Bradyrhizobium japonicum or from Rhizobium meliloti. Non-denaturing PAGE showed that GSII, either in crude extracts or in the pure state, was a mixture of an octamer and a tetramer and that under specific conditions the octamer/tetramer ratio could be modified in either direction. The pure enzyme was used to raise an antiserum which was highly specific. Addition of NH4Cl to a bacterial culture derepressed for GSII caused a specific decrease in transferase activity, faster than the one observed when the amount of immunoreactive material was measured by different methods. On the other hand, biosynthetic activity, measured as the rate of ADP or glutamine formation, paralleled the rate of decrease in immunoreactive material. A partially purified enzyme preparation retained this dissociation of kinetic parameters, strongly suggesting a post-translational modification. These findings are discussed with respect to the possible role of GSII in the Rhizobium-legume symbiosis.     

A partnership project for a new Red List of the Italian Flora

Abstract

The IUCN Red Lists assessment provides an internationally accepted system to verify the extinction risk of species. Working Groups of the Italian Botanical Society have recently discussed the importance of producing a reliable list of species at the national level. This list could be the starting point for future in situ and ex situ plant conservation activities.