Effects of hypoxia and fatty acids on the distribution of metabolites in rat heart

The effects of exogenous fatty acids and hypoxia on cardiac energy metabolism were studied by measuring mitochondrial and cytosolic adenine nucleotides as well as CoA and carnitine esters using a tissue fractionation technique in non-aqueous solvents. During normoxia, the administration of 0.5 mM palmitate caused a considerable increase in acyl-CoA and acylcarnitine, particularly in mitochondria. High-energy phosphates, however, were only slightly altered. A 90 min low-flow hypoxia caused a dramatic increase in mitochondrial acyl esters. The mitochondrial ATP content decreased significantly, while the cytosolic concentration was only slightly diminished, suggesting an inhibition of mitochondrial adenine nucleotide translocation by long-chain acyl-CoA. Addition of palmitate during hypoxia amplified hypoxic damage and reduced adenine nucleotides in both compartments considerably, while fatty acid metabolites were only slightly affected. In presence of an inhibitor of fatty acid oxidation (BM 42.304), the fatty-acid-induced acceleration of cardiac injury was prevented. Since BM 42.304 decreased mitochondrial acylcarnitine and increased the cytosolic concentration significantly, BM 42.304 was presumed to inhibit mitochondrial acylcarnitine translocase. However, a causal relationship between lipid metabolites and ischemic damage seemed unlikely.     

Exploring the Factor Structure of Neurocognitive Measures in Older Individuals

Here we focus on factor analysis from a best practices point of view, by investigating the factor structure of neuropsychological tests and using the results obtained to illustrate on choosing a reasonable solution. The sample (n=1051 individuals) was randomly divided into two groups: one for exploratory factor analysis (EFA) and principal component analysis (PCA), to investigate the number of factors underlying the neurocognitive variables; the second to test the “best fit” model via confirmatory factor analysis (CFA). For the exploratory step, three extraction (maximum likelihood, principal axis factoring and principal components) and two rotation (orthogonal and oblique) methods were used. The analysis methodology allowed exploring how different cognitive/psychological tests correlated/discriminated between dimensions, indicating that to capture latent structures in similar sample sizes and measures, with approximately normal data distribution, reflective models with oblimin rotation might prove the most adequate.     

Different Patterns of White Matter Degeneration Using Multiple Diffusion Indices and Volumetric Data in Mild Cognitive Impairment and Alzheimer Patients

Alzheimeŕs disease (AD) represents the most prevalent neurodegenerative disorder that causes cognitive decline in old age. In its early stages, AD is associated with microstructural abnormalities in white matter (WM). In the current study, multiple indices of diffusion tensor imaging (DTI) and brain volumetric measurements were employed to comprehensively investigate the landscape of AD pathology. The sample comprised 58 individuals including cognitively normal subjects (controls), amnestic mild cognitive impairment (MCI) and AD patients. Relative to controls, both MCI and AD subjects showed widespread changes of anisotropic fraction (FA) in the corpus callosum, cingulate and uncinate fasciculus. Mean diffusivity and radial changes were also observed in AD patients in comparison with controls. After controlling for the gray matter atrophy the number of regions of significantly lower FA in AD patients relative to controls was decreased; nonetheless, unique areas of microstructural damage remained, e.g., the corpus callosum and uncinate fasciculus. Despite sample size limitations, the current results suggest that a combination of secondary and primary degeneration occurrs in MCI and AD, although the secondary degeneration appears to have a more critical role during the stages of disease involving dementia.     

Euclein: A new binaphthaquinone from Euclea pseudebenus

7-MethyljugIone, 8,8′-dihydroxy-4,4′-dimethoxy-6,6′-dimethyl-2,2′-binaphthyl-1,1′-quinone, 2-methylnaphthazarin, mamegakinone and euclein have been isolated from Euclea pseudebenus. Euclein is the 3,6′-dimer of 7-methyljuglone.     

β-N-Acetylhexosaminidase involvement in α-conglutin mobilization in Lupinus albus

Glycosylation is an important post-translational modification involved in the modulation of a wide variety of cellular processes. Because glycosydases are central, the aim of this study was to investigate the glycosyl activity present in the cotyledons of the seeds of an important crop legume, Lupinus albus, as well as potential natural substrates of the detected enzymes.     

Cryptic speciation in the field vole: a multilocus approach confirms three highly divergent lineages in Eurasia

Species are generally described from morphological features, but there is growing recognition of sister forms that show substantial genetic differentiation without obvious morphological variation and may therefore be considered ‘cryptic species’. Here, we investigate the field vole (Microtus agrestis), a Eurasian mammal with little apparent morphological differentiation but which, on the basis of previous sex‐linked nuclear and mitochondrial DNA (mtDNA) analyses, is subdivided into a Northern and a Southern lineage, sufficiently divergent that they may represent two cryptic species. These earlier studies also provided limited evidence for two major mtDNA lineages within Iberia. In our present study, we extend these findings through a multilocus approach. We sampled 163 individuals from 46 localities, mainly in Iberia, and sequenced seven loci, maternally, paternally and biparentally inherited. Our results show that the mtDNA lineage identified in Portugal is indeed a distinct third lineage on the basis of other markers as well. In fact, multilocus coalescent‐based methods clearly support three separate evolutionary units that may represent cryptic species: Northern, Southern and Portuguese. Divergence among these units was inferred to have occurred during the last glacial period; the Portuguese lineage split occurred first (estimated at c. 70 000 bp ), and the Northern and Southern lineages separated at around the last glacial maximum (estimated at c. 18 500 bp ). Such recent formation of evolutionary units that might be considered species has repercussions in terms of understanding evolutionary processes and the diversity of small mammals in a European context.     

Structure and Evolution of the Mitochondrial DNA Complete Control Region in the Lizard Lacerta dugesii (Lacertidae, Sauria)

Abstract We sequenced the complete control region (CR) and adjacent tRNAs, partial 12S rRNA, and cytochrome b (over 3100 bp) from eight individuals of Madeiran wall lizards, Lacerta dugesii, from four distinct island populations. The tRNAs exhibit a high degree of intraspecific polymorphisms compared to other vertebrates. All CR sequences include a minisatellite that varies in length between populations but is apparently fixed within them. Variation in minisatellite length appears between populations separated by apparently very short evolutionary time spans. Many motifs identified in the CR of other vertebrates are not highly conserved, although conserved blocks are identifiable between the few published reptile CR sequences. Overall there are extensive differences in the internal organization of the reptile CR compared to the more widely studied mammals and birds. Variability in the CR is lower than in cytochrome b, but higher than in 12S rRNA. Phylogenetic analysis of these sequences produces a well-resolved estimate of relationships between populations.     

Allometric growth and adaptive value of exaggerated body parts in the larvae of Gratiana spadicea (Klug) (Coleoptera: Chrysomelidae)

1. Larvae of tortoise beetles present exaggerated body parts in association with an abdominal shield, which is made of faeces and exuviae that are deposited on the urogomphi throughout ontogeny. Growth trajectories and scaling relationships of these functional structures associated with the shield, if any, are unknown. 2. This study of Gratiana spadicea first tested, under field conditions, whether there is adaptive value associated with the shield regarding protection against predation and sunlight. Then, under laboratory conditions, the growth trajectory and allometric relationships among body parts were investigated, including scoli, individual and apparent furcae, and shield. The influence of food deprivation on the development of these structures was also determined. 3. Findings from previous studies were confirmed, suggesting that the adaptive value assigned to the shield is related to protection against predators. The present study demonstrated for the first time that the shield acts as a parasol in cassidines, decreasing the exposure of their larval body to sunlight. The scoli and apparent furca are exaggerated structures of G. spadicea, the development of which involves allometric growth and greater energetic investment (positive allometry) during ontogeny. There was proportionally less energetic investment for somatic construction of individual furca (negative allometry) due to the accumulation of the exuviae. 4. The possible consequences, in terms of developmental costs and survivorship benefits associated with the evolution of such exaggerated structures, are discussed.     

Catch Me If You Can: Diel Activity Patterns of Mammalian Prey and Predators

The activity patterns exhibited by animals are shaped by evolution, but additionally fine‐tuned by flexible responses to the environment. Predation risk and resource availability are environmental cues which influence the behavioural decisions that make both predators and prey engage in activity bursts, and depending on their local importance, can be strong enough to override the endogenous regulation of an animals’ circadian clock. In Southern Europe, wherever the European rabbit (Oryctolagus cuniculus) is abundant, it is the main prey of most mammalian mesopredators, and rodents are generally the alternative prey. We evaluated the bidirectional relation between the diel activity strategies of these mammalian mesopredators and prey coexisting in south‐western Europe. Results revealed that even though predation risk enforced by mammalian mesocarnivores during night‐time was approximately twice and five times higher than during twilight and daytime, respectively, murids consistently displayed unimodal nocturnal behaviour. Conversely, the European rabbits exhibited a bimodal pattern that peaked around sunrise and sunset. Despite the existence of some overlap between the diel rhythms of mesocarnivores and rabbits, their patterns were not synchronized. We suggest that the environmental stressors in our study areas are not severe enough to override the endogenous regulation of the circadian cycle in murids. European rabbits, however, are able to suppress their biological tendency for nocturnality by selecting a predominantly crepuscular pattern. In spite of the higher energetic input, mesocarnivores do not completely track rabbits’ activity pattern. They rather track rodents’ activity. We propose that these systems have probably evolved towards a situation where some degree of activity during high‐risk periods benefits the overall prey population survival, while the accessibility to sufficient prey prevents predators to completely track them.