Effects of Transient and Continuous Wheel Running Activity on the Upper and Lower Limits of Entrainment to Light‐Dark Cycles in Female Hamsters

The entrainment limits to light‐dark cycles can be modified by the experimental conditions under which they are tested. Among the factors that may influence entrainment is the amount of wheel running exerted by the animal. In the present work, the effects of transitory and continuous wheel running on entrainment to light‐dark cycles were tested using a range of T cycles at the entrainment limits. Four groups of female hamsters were submitted to 1 h stepwise changes in T cycles. Two groups were exposed to T cycles of which the period was shortened at the lower limit from T22 to T18, and the other two groups were exposed to cycles that lengthened at the upper limit from T27 to T32. One of the groups at the lower limit and one at the upper limit had continuous access to a running wheel, while the others had the wheel locked, except at certain T when a lack of period control by T cycle appeared. The study demonstrates that access to running wheel widens the limits of entrainment to LD cycles. Specifically, the following observations were made: the effects of wheel running for entrainment were more evident in the groups with continuous access to wheel, as they did entrain to T19 and T32; continuous access to a wheel produced aftereffects only after T19, but not under T32; and when animals without a wheel showed relative coordination, unlocking the wheel favored entrainment in all the animals at T31, but in only 1 out 6 at T19. All of these indicate a different effect of the wheel running on the upper and lower limits of entrainment.     

Geographical patterns of genetic variation in rosemary (Rosmarinus officinalis) in the Mediterranean basin

Climate changes during the Quaternary had important effects on the evolution of European plant species. The distribution of genetic variability in rosemary, a strictly Mediterranean species of reputed Plio‐Quaternary origin for which the diversification centre is hypothesized to be located in the western part of the Mediterranean basin, was investigated across the species range by using plastid microsatellites [plastid simple sequence repeat (cpSSR)] markers. Seven out of the 17 primer pairs screened were polymorphic, with up to four alleles, yielding a total of 17 size variants combined into ten haplotypes. A permutation test to investigate for geographical structure showed no significant differences between R_ST and G_ST, indicating that the species lacks geographical structure. Low correlation between genetic and geographical distances was shown by the Mantel test. Bayesian analysis identified two coancestry groups of populations. The distribution of genetic diversity supports the hypothesized origin in the western Mediterranean basin, and with the demographic expansion test indicates three different routes of migration: a northern route expanding along the northern side of the Mediterranean and two southern routes, one from west to east through North Africa and reaching Cyrenaica, and a second to the south‐west of the Iberian Peninsula, from where it came back to the south–central areas. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013 , 171 , 700–712.     

hCOA3 Stabilizes Cytochrome c Oxidase 1 (COX1) and Promotes Cytochrome c Oxidase Assembly in Human Mitochondria

Cytochrome c oxidase (COX) or complex IV of the mitochondrial respiratory chain plays a fundamental role in energy production of aerobic cells. In humans, COX deficiency is the most frequent cause of mitochondrial encephalomyopathies. Human COX is composed of 13 subunits of dual genetic origin, whose assembly requires an increasing number of nuclear-encoded accessory proteins known as assembly factors. Here, we have identified and characterized human CCDC56, an 11.7-kDa mitochondrial transmembrane protein, as a new factor essential for COX biogenesis. CCDC56 shares sequence similarity with the yeast COX assembly factor Coa3 and was termed hCOA3. hCOA3-silenced cells display a severe COX functional alteration owing to a decreased stability of newly synthesized COX1 and an impairment in the holoenzyme assembly process. We show that hCOA3 physically interacts with both the mitochondrial translation machinery and COX structural subunits. We conclude that hCOA3 stabilizes COX1 co-translationally and promotes its assembly with COX partner subunits. Finally, our results identify hCOA3 as a new candidate when screening for genes responsible for mitochondrial diseases associated with COX deficiency.     

Pollution in mediterranean-climate rivers

This review examines information generated over the past decade on the pollution of rivers in regions with a mediterranean-type climate (med-climate). Pollution has clearly increased in the last 100 years and is correlated with the development of industry, agriculture and human population. Important efforts have been made in some med-climate countries in order to characterise the chemical status of rivers. In addition, the number of chemical substances detectable in mediterranean-climate rivers (med-rivers), as well as the limits of detection, have improved from the development of better analytical methods. New substances detected in rivers are gaining attention. We discuss available knowledge regarding real and potential effects of pollutants on the biota and ecosystems in med-rivers, taking into account natural environmental characteristics of these rivers. The extreme seasonal conditions in med-rivers add to the potential risk because these characteristics can enhance pollutant effects. Efforts and policies to prevent or reduce pollution effects on med-rivers are linked to the knowledge about pollution pressures associated with the degree of economic development. Aquatic communities in med-rivers are more sensitive to pollutants because they are exposed to strong natural and human stressors.     

Manufacturing of peptides exhibiting biological activity

Numerous studies have shown that food proteins may be a source of bioactive peptides. Those peptides are encrypted in the protein sequence. They stay inactive within the parental protein until release by proteolytic enzymes (Mine and Kovacs-Nolan in Worlds Poult Sci J 62(1):87–95, 2006; Hartman and Miesel in Curr Opin Biotechnol 18:163–169, 2007). Once released the bioactive peptides exhibit several biofunctionalities and may serve therapeutic roles in body systems. Opioid peptides, peptides lowering high blood pressure, inhibiting platelet aggregation as well as being carriers of metal ions and peptides with immunostimulatory, antimicrobial and antioxidant activities have been described (Hartman and Miesel in Curr Opin Biotechnol 18:163–169, 2007). The biofunctional abilities of the peptides have therefore aroused a lot of scientific, technological and consumer interest with respect to the role of dietary proteins in controlling and influencing health (Möller et al. in Eur J Nutr 47(4):171–182, 2008). Biopeptides may find wide application in food production, the cosmetics industry as well as in the prevention and treatment of various medical conditions. They are manufactured by chemical and biotechnological methods (Marx in Chem Eng News 83(11):17–24. 2005; Hancock and Sahl in Nat Biotechnol 24(12):1551–1557, 2006). Depending on specific needs (food or pharmaceutical industry) different degrees of peptide purifications are required. This paper discusses the practicability of manufacturing bioactive peptides, especially from food proteins.     

Global characterisation factors to assess land use impacts on biotic production

Purpose

The inclusion of land-use activities in life cycle assessment (LCA) has been subject to much debate in the LCA community. Despite the recent methodological developments in this area, the impacts of land occupation and transformation on its long-term ability to produce biomass (referred to here as biotic production potential [BPP]) — an important endpoint for the Area of Protection (AoP) Natural Resources — have been largely excluded from LCAs partly due to the lack of life cycle impact assessment methods.

Materials and methods

Several possible methods/indicators for BPP associated with biomass, carbon balance, soil erosion, salinisation, energy, soil biota and soil organic matter (SOM) were evaluated. The latter indicator was considered the most appropriate for LCA, and characterisation factors for eight land use types at the climate region level were developed.

Results and discussion

Most of the indicators assessed address land-use impacts satisfactorily for land uses that include biotic production of some kind (agriculture or silviculture). However, some fail to address potentially important land use impacts from other life cycle stages, such as those arising from transport. It is shown that the change in soil organic carbon (SOC) can be used as an indicator for impacts on BPP, because SOC relates to a range of soil properties responsible for soil resilience and fertility.

Conclusions

The characterisation factors developed suggest that the proposed approach to characterize land use impacts on BBP, despite its limitations, is both possible and robust. The availability of land-use-specific and biogeographically differentiated data on SOC makes BPP impact assessments operational. The characterisation factors provided allow for the assessment of land-use impacts on BPP, regardless of where they occur thus enabling more complete LCAs of products and services. Existing databases on every country’s terrestrial carbon stocks and land use enable the operability of this method. Furthermore, BPP impacts will be better assessed by this approach as increasingly spatially specific data are available for all geographical regions of the world at a large scale. The characterisation factors developed are applied to the case studies (Part D of this special issue), which show the practical issues related to their implementation.     

Cocaine Inhibits Dopamine D2 Receptor Signaling via Sigma-1-D2 Receptor Heteromers

Under normal conditions the brain maintains a delicate balance between inputs of reward seeking controlled by neurons containing the D₁-like family of dopamine receptors and inputs of aversion coming from neurons containing the D₂-like family of dopamine receptors. Cocaine is able to subvert these balanced inputs by altering the cell signaling of these two pathways such that D₁ reward seeking pathway dominates. Here, we provide an explanation at the cellular and biochemical level how cocaine may achieve this. Exploring the effect of cocaine on dopamine D₂ receptors function, we present evidence of σ₁ receptor molecular and functional interaction with dopamine D₂ receptors. Using biophysical, biochemical, and cell biology approaches, we discovered that D₂ receptors (the long isoform of the D₂ receptor) can complex with σ₁ receptors, a result that is specific to D₂ receptors, as D₃ and D₄ receptors did not form heteromers. We demonstrate that the σ₁-D₂ receptor heteromers consist of higher order oligomers, are found in mouse striatum and that cocaine, by binding to σ₁ -D₂ receptor heteromers, inhibits downstream signaling in both cultured cells and in mouse striatum. In contrast, in striatum from σ₁ knockout animals these complexes are not found and this inhibition is not seen. Taken together, these data illuminate the mechanism by which the initial exposure to cocaine can inhibit signaling via D₂ receptor containing neurons, destabilizing the delicate signaling balance influencing drug seeking that emanates from the D₁ and D₂ receptor containing neurons in the brain.