Assay of the concentration and (13)C isotopic enrichment of propionyl-CoA,methylmalonyl-CoA,and succinyl-CoA by gas chromatography-mass spectrometry

We developed gas chromatography-mass spectrometry assays for the concentration and mass isotopomer distribution of propionyl-CoA, methylmalonyl-CoA, and succinyl-CoA in tissues. The assays involves perchloric acid extraction of the tissue, spiking the extract with [(2)H(5)]propionyl-CoA and [(2)H(4)]succinyl-CoA internal standards, and isolation of short-chain acyl-CoA fraction on an oligonucleotide purification cartridge. Propionyl-CoA is reacted with sarcosine and the formed N-propionylsarcosine is assayed as its pentafluorobenzyl derivative. Methylmalonyl-CoA and succinyl-CoA are hydrolyzed and the corresponding acids assayed as tert-butyl dimethylsilyl derivatives. The assay was applied to a study of [U-(13)C(3)]propionate metabolism in perfused rat livers. While propionyl-CoA is only M3 labeled, succinyl-CoA is M3, M2, and M1 labeled because of isotopic exchanges in the citric acid cycle. Methylmalonyl-CoA is M3 and M2 labeled, reflecting reversal of S-methylmalonyl-CoA mutase. Thus, our assays allow measuring the turnover of the coenzyme A derivatives involved in anaplerosis of the citric acid cycle via precursors of propionyl-CoA, i.e., propionate, odd-chain fatty acids, isoleucine, threonine, and valine.     

Une nouvelle espèce de Podocnemis (Pleurodira, Podocnemididae) provenant du Néogène de la formation Solimões, Acre, Brésil

A Neogene turtle from Brasil is described. It represents the first find of a new species close to the extant Podocnemis sextuberculata. Both species constitute a new clade in the genus. The synapomorphies they share and the differences between them are given. P. negrii nov. sp. is the second fossil species of the genus, after P. bassleri from the Neogene of Peru, which constitutes another clade with the extant P. expansa. The relationships between these two clades and the other species of the genus are not determinate.     

Beaver alter stable carbon isotope ratios of benthic particulate organic matter

Beaver are well known to influence the geomorphology and geochemistry of boreal waters, in addition to being prominent vectors in the selective import of deciduous coarse woody debris (CWD). Because the stable carbon isotope ratios of deciduous trees are lower than those of coniferous trees, the possibility exists that the ¹³C values of particulate organic matter near beaver lodges may differ from those characteristic for littoral regions without beaver activity. In agreement with this supposition, ¹³C was found to significantly increase in progressively smaller size fractions of CWD collected from near lodges, probably due to the more rapid breakdown, decomposition and disappearance of deciduous material.     

On the two-compartment model for estimating the rate and extent of feed degradation in the rumen

An analysis of the compartmental scheme used to determine the rate and extent of ruminal degradation of feeds is presented. Attention is given to the kinetic representation of the degradation of the potentially degradable fraction. Changing the kinetic order of the rate, and introducing indigestible substrate inhibition and microbial activity into its representation, are investigated. This leads to response functions such as the Gompertz and logistic for describing the cumulative disappearance of potentially degradable substrate during in-sacco and in-vitro incubation.     

Pseudomonas putida and Pseudomonas fluorescens Species Group Recovery from Human Homes Varies Seasonally and by Environment

By shedding light on variation in time as well as in space, long-term biogeographic studies can help us define organisms’ distribution patterns and understand their underlying drivers. Here we examine distributions of Pseudomonas in and around 15 human homes, focusing on the P. putida and P. fluorescens species groups. We describe recovery from 10,941 samples collected during up to 8 visits per home, occurring on average 2.6 times per year. We collected a mean of 141 samples per visit, from sites in most rooms of the house, from the surrounding yards, and from human and pet occupants. We recovered Pseudomonas in 9.7% of samples, with the majority of isolates being from the P. putida and P. fluorescens species groups (approximately 62% and 23% of Pseudomonas samples recovered respectively). Although representatives of both groups were recovered from every season, every house, and every type of environment sampled, recovery was highly variable across houses and samplings. Whereas recovery of P. putida group was higher in summer and fall than in winter and spring, P. fluorescens group isolates were most often recovered in spring. P. putida group recovery from soils was substantially higher than its recovery from all other environment types, while higher P. fluorescens group recovery from soils than from other sites was much less pronounced. Both species groups were recovered from skin and upper respiratory tract samples from healthy humans and pets, although this occurred infrequently. This study indicates that even species that are able to survive under a broad range of conditions can be rare and variable in their distributions in space and in time. For such groups, determining patterns and causes of stochastic and seasonal variability may be more important for understanding the processes driving their biogeography than the identity of the types of environments in which they can be found.     

Association between Mindfulness and Weight Status in a General Population from the NutriNet-Santé Study

Background

Mindfulness is defined as non-judgmental awareness of the present moment. There is some evidence of the efficacy of mindfulness-based interventions in weight loss. However, this psychological concept has only been rarely explored in observational studies, and no study to date has examined the association between dispositional mindfulness and weight status in a large population-based sample.

Objective

We aimed to examine the relationship between mindfulness scores and weight status in a large sample of the adult general population in France.

Design and Methods

A total of 14,400 men and 49,228 women aged ≥18 y participating in the NutriNet-Santé study were included in this cross-sectional analysis. We collected mindfulness data using the Five Facet Mindfulness Questionnaire as well as self-reported weight and height. The association between weight status and dispositional mindfulness, as well as its subscales (observing, describing, acting with awareness, non-judging and non-reactivity), was assessed using multinomial logistic regression models adjusted for socio-demographic and lifestyle factors.

Results

Women with higher dispositional mindfulness scores were less likely to be overweight (excluding obesity) (OR quartile 4 vs. 1 = 0.84, 95% CI: 0.79-0.90) and obese (OR quartile 4 vs. 1 = 0.71, 95% CI: 0.65-0.78). In addition, overall, in this group, all subscales were inversely associated with weight status, with the strongest association found for the “observing” subscale. In men, higher mindfulness was associated only with lower odds of obesity (OR quartile 4 vs. 1 = 0.81 (0.69, 0.96)), and only the “observing” and “non-reactivity” subscales were significantly inversely associated with weight status.

Conclusion

Results support the interest of a shift in perspective that takes into account positive psychological and cognitive factors such as dispositional mindfulness in the investigation of obesity and its associated factors.