Molecular phylogeny and evolution of the extinct bovid Myotragus balearicus

Myotragus balearicus was a dwarf artiodactyl endemic to the Eastern Balearic Islands, where it evolved in isolation for more than 5 million years before becoming extinct between 3640 and 2135 cal BC (calibrated years BC). Numerous unusual apomorphies obscure the relationship between Myotragus and the extant Caprinae. Therefore, genetic data for this species would significantly contribute to the clarification of its taxonomic position. In this study, we amplify, sequence, and clone a 338-base pair (bp) segment of the mitochondrial cytochrome b (cyt b) gene from a >9Kyr Myotragus subfossil from la Cova des Gorgs (Mallorca). Our results confirm the phylogenetic affinity of Myotragus with the sheep (Ovis) and the takin (Budorcas). In each tree, the Myotragus branch is long in comparison with the other taxa, which may be evidence of a local change in the rate of evolution in cyt b. This rate change may be due to in part to an early age of first reproduction and short generation time in Myotragus, factors that are potentially related to the extreme reduction in size of the adult Myotragus as compared to the other Caprinae.     

Natural selection for kinetic stability is a likely origin of correlations between mutational effects on protein energetics and frequencies of amino acid occurrences in sequence alignments

It appears plausible that natural selection constrains, to some extent at least, the stability in many natural proteins. If, during protein evolution, stability fluctuates within a comparatively narrow range, then mutations are expected to be fixed with frequencies that reflect mutational effects on stability. Indeed, we recently reported a robust correlation between the effect of 27 conservative mutations on the thermodynamic stability (unfolding free energy) of Escherichia coli thioredoxin and the frequencies of residues occurrences in sequence alignments. We show here that this correlation likely implies a lower limit to thermodynamic stability of only a few kJ/mol below the unfolding free energy of the wild-type (WT) protein. We suggest, therefore, that the correlation does not reflect natural selection of thermodynamic stability by itself, but of some other factor which is linked to thermodynamic stability for the mutations under study. We propose that this other factor is the kinetic stability of thioredoxin in vivo, since( i) kinetic stability relates to irreversible denaturation, (ii) the rate of irreversible denaturation in a crowded cellular environment (or in a harsh extracellular environment) is probably determined by the rate of unfolding, and (iii) the half-life for unfolding changes in an exponential manner with activation free energy and, consequently, comparatively small free energy effects can have deleterious consequences for kinetic stability. This proposal is supported by the results of a kinetic study of the WT form and the 27 single-mutant variants of E. coli thioredoxin based on the global analyses of chevron plots and equilibrium unfolding profiles determined from double-jump unfolding assays. This kinetic study suggests, furthermore, one of the factors that may contribute to the high activation free energy for unfolding in thioredoxin (required for kinetic stability), namely the energetic optimization of native-state residue environments in regions, which become disrupted in the transition state for unfolding.     

Life cycle assessment comparison among different reuse intensities for industrial wooden containers

Goal, scope and background  The industrial packages sector has great importance for the transport sector in Europe. These containers, mainly wooden pallets and spools, are subject to European legislation, which promotes their reuse and recycling. This study uses life cycle assessment (LCA) to assess the environmental impact of the current management system in this sector and the benefits and drawbacks of different reuse intensities as a waste prevention strategy as opposed to the recycling option. Materials and methods  In this paper, four case studies located in Spain and representative of the wooden package sector in Europe are analysed: high reuse pallet, low reuse pallet, low reuse spool and null reuse spool. For the LCA study cases, the functional unit is that required to satisfy the transport necessity of 1,000 t by road. The impact and energy consumption assessment methods used are CML 2 Baseline 2000 and Cumulative Energy Demand. Data are mostly provided by the leading enterprises and organisations in this sector. Results  The paper provides, as a first result, a comprehensive inventory of the systems under study. Secondly, our assessment shows that the systems with higher reuse intensity show a reduction in energy and wood consumption and all the environmental impact categories except for the global warming potential from 34.0% to 81.0% in the pallet study cases and from 50.4% to 72.8% in the spool ones. This reduction is at the expense of the maintenance stage, which on the contrary increases its impact, although it is still relatively small—less than 7% in all the impact categories and flow indicators of the study cases. The highest impact stages are transport, raw material extraction and the process chain. The final disposal and maintenance stages are the lowest impact, contributing at most to less than 30% of the impact in the pallet study cases and 10% in the spool cases. Discussion  Wood consumption (WC), directly related to the number of containers needed to satisfy the functional unit, is the main factor in determining the impact of the stages, especially in the raw materials extraction and process chain stages, assuming that these are undertaken with the same technologies in all the case studies. Other variables, such as the management system, the maintenance index and the final disposal scenario, affect the impact of the remaining stages: transport, maintenance and final disposal. The global warming potential results obtained demonstrate the environmental benefits of using containers made of a renewable resource such as wood instead of using other materials, but these results are not expected to prioritise the lower reuse systems because of their better performance in this category. Conclusions  Reuse, a strategy capable of reducing the environmental impacts of the wooden container systems, is preferable to recycling, while the package maintenance tasks are still feasible. Therefore, reuse, combined with recycling as final disposal, should be encouraged to reduce the demand for natural resources and the waste generated. Recommendations  Based on these results, attention should be paid to the maintenance stage, which, being the lowest-impact one, could substantially reduce the impact of the remaining stages.     

In vitro antiprotozoal activity of alkaloids from Phaedranassa dubia (Amaryllidaceae)

The bulbs of Phaedranassa dubia (Amaryllidaceae) were found to contain the novel compound phaedranamine, together with seven known alkaloids. The structure and stereochemistry of the alkaloids were determined by physical and spectroscopic methods. An in vitro screening against four different parasitic protozoa was carried out using the isolated compounds. The alkaloids ungeremine, pseudolycorine and haemanthamine showed good activity in in vitro assays against Trypanosoma brucei rhodesiense, T. cruzi and Plasmodium falciparum with IC₅₀ values in the range of 3.66 μM or lower.     

Patterns in Abundance,Cell Size and Pigment Content of Aerobic Anoxygenic Phototrophic Bacteria along Environmental Gradients in Northern Lakes

There is now evidence that aerobic anoxygenic phototrophic (AAP) bacteria are widespread across aquatic systems, yet the factors that determine their abundance and activity are still not well understood, particularly in freshwaters. Here we describe the patterns in AAP abundance, cell size and pigment content across wide environmental gradients in 43 temperate and boreal lakes of Québec. AAP bacterial abundance varied from 1.51 to 5.49 x 10⁵ cells mL^-1, representing <1 to 37% of total bacterial abundance. AAP bacteria were present year-round, including the ice-cover period, but their abundance relative to total bacterial abundance was significantly lower in winter than in summer (2.6% and 7.7%, respectively). AAP bacterial cells were on average two-fold larger than the average bacterial cell size, thus AAP cells made a greater relative contribution to biomass than to abundance. Bacteriochlorophyll a (BChla) concentration varied widely across lakes, and was not related to AAP bacterial abundance, suggesting a large intrinsic variability in the cellular pigment content. Absolute and relative AAP bacterial abundance increased with dissolved organic carbon (DOC), whereas cell-specific BChla content was negatively related to chlorophyll a (Chla). As a result, both the contribution of AAP bacteria to total prokaryotic abundance, and the cell-specific BChla pigment content were positively correlated with the DOC:Chla ratio, both peaking in highly colored, low-chlorophyll lakes. Our results suggest that photoheterotrophy might represent a significant ecological advantage in highly colored, low-chlorophyll lakes, where DOC pool is chemically and structurally more complex.     

Regularity of Cardiac Rhythm as a Marker of Sleepiness in Sleep Disordered Breathing

Aim

The present study aimed to analyse the autonomic nervous system activity using heart rate variability (HRV) to detect sleep disordered breathing (SDB) patients with and without excessive daytime sleepiness (EDS) before sleep onset.

Methods

Two groups of 20 patients with different levels of daytime sleepiness -sleepy group, SG; alert group, AG- were selected consecutively from a Maintenance of Wakefulness Test (MWT) and Multiple Sleep Latency Test (MSLT) research protocol. The first waking 3-min window of RR signal at the beginning of each nap test was considered for the analysis. HRV was measured with traditional linear measures and with time-frequency representations. Non-linear measures -correntropy, CORR; auto-mutual-information function, AMIF- were used to describe the regularity of the RR rhythm. Statistical analysis was performed with non-parametric tests.

Results

Non-linear dynamic of the RR rhythm was more regular in the SG than in the AG during the first wakefulness period of MSLT, but not during MWT. AMIF (in high-frequency and in Total band) and CORR (in Total band) yielded sensitivity > 70%, specificity >75% and an area under ROC curve > 0.80 in classifying SG and AG patients.

Conclusion

The regularity of the RR rhythm measured at the beginning of the MSLT could be used to detect SDB patients with and without EDS before the appearance of sleep onset.     

Improving Assessment of Lipoprotein Profile in Type 1 Diabetes by 1H NMR Spectroscopy

Patients with type 1 diabetes (T1D) present increased risk of cardiovascular disease (CVD). The aim of this study is to improve the assessment of lipoprotein profile in patients with T1D by using a robust developed method 1H nuclear magnetic resonance spectroscopy (1H NMR), for further correlation with clinical factors associated to CVD. Thirty patients with T1D and 30 non-diabetes control (CT) subjects, matched for gender, age, body composition (DXA, BMI, waist/hip ratio), regular physical activity levels and cardiorespiratory capacity (VO_2peak), were analyzed. Dietary records and routine lipids were assessed. Serum lipoprotein particle subfractions, particle sizes, and cholesterol and triglycerides subfractions were analyzed by 1H NMR. It was evidenced that subjects with T1D presented lower concentrations of small LDL cholesterol, medium VLDL particles, large VLDL triglycerides, and total triglycerides as compared to CT subjects. Women with T1D presented a positive association with HDL size (p<0.005; R = 0.601) and large HDL triglycerides (p<0.005; R = 0.534) and negative (p<0.005; R = -0.586) to small HDL triglycerides. Body fat composition represented an important factor independently of normal BMI, with large LDL particles presenting a positive correlation to total body fat (p<0.005; R = 0.505), and total LDL cholesterol and small LDL cholesterol a positive correlation (p<0.005; R = 0.502 and R = 0.552, respectively) to abdominal fat in T1D subjects; meanwhile, in CT subjects, body fat composition was mainly associated to HDL subclasses. VO_2peak was negatively associated (p<0.005; R = -0.520) to large LDL-particles only in the group of patients with T1D. In conclusion, patients with T1D with adequate glycemic control and BMI and without chronic complications presented a more favourable lipoprotein profile as compared to control counterparts. In addition, slight alterations in BMI and/or body fat composition showed to be relevant to provoking alterations in lipoproteins profiles. Finally, body fat composition appears to be a determinant for cardioprotector lipoprotein profile.