The genome sequence of the leaf-cutter ant Atta cephalotes reveals insights into its obligate symbiotic lifestyle

Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects). Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host-microbe symbioses.     

Mitochondrial respiratory control and early defects of oxidative phosphorylation in the failing human heart

Heart failure is a consequence of progressive deterioration of cardiac performance. Little is known about the role of impaired oxidative phosphorylation in the progression of the disease, since previous studies of mitochondrial injuries are restricted to end-stage chronic heart failure. The present study aimed at evaluating the involvement of mitochondrial dysfunction in the development of human heart failure. We measured the control of oxidative phosphorylation with high-resolution respirometry in permeabilized myocardial fibres from donor hearts (controls), and patients with no or mild heart failure but presenting with heart disease, or chronic heart failure due to dilated or ischemic cardiomyopathy. The capacity of the phosphorylation system exerted a strong limitation on oxidative phosphorylation in the human heart, estimated at 121 pmol O(2)s(-1)mg(-1) in the healthy left ventricle. In heart disease, a specific defect of the phosphorylation system, Complex I-linked respiration, and mass-specific fatty acid oxidation were identified. These early defects were also significant in chronic heart failure, where the capacities of the oxidative phosphorylation and electron transfer systems per cardiac tissue mass were decreased with all tested substrate combinations, suggesting a decline of mitochondrial density. Oxidative phosphorylation and electron transfer system capacities were higher in ventricles compared to atria, but the impaired mitochondrial quality was identical in the four cardiac chambers of chronic heart failure patients. Coupling was preserved in heart disease and chronic heart failure, in contrast to the mitochondrial dysfunction observed after prolonged cold storage of cardiac tissue. Mitochondrial defects in the phosphorylation system, Complex I respiration and mass-specific fatty acid oxidation occurred early in the development of heart failure. Targeting these mitochondrial injuries with metabolic therapy may offer a promising approach to delay the progression of heart disease.     

Impact of diabetes on alpha-crystallins and other heat shock proteins in the eye

Diabetes and its related complications represent a major growing health concern and economic burden worldwide. Ocular manifestations of diabetes include cataractogenesis and retinopathy, the latter being the leading cause of blindness in the working-age population. Despite numerous studies and recent progress, the exact pathophysiology of the disease remains to be fully elucidated and development of new and improved therapeutic strategies for this chronic condition are greatly needed. Heat shock proteins (Hsps) are highly conserved families of proteins, which are generally regarded as protective molecules that play a wide variety of roles and can be expressed in response to different types of cellular stresses. In recent years, numerous studies have reported their implication in various ocular diseases including diabetic retinopathy. The present review focuses on the potential implication of Hsps in ocular diabetic complications and discusses their specific mechanisms of regulation with respect to their expression, functions and alteration during diabetes. The review will conclude by examining the potential of Hsps as therapeutic agents or targets for the treatment of diabetic retinopathy.     

IL-22 is produced by innate lymphoid cells and limits inflammation in allergic airway disease

Interleukin (IL)-22 is an effector cytokine, which acts primarily on epithelial cells in the skin, gut, liver and lung. Both pro- and anti-inflammatory properties have been reported for IL-22 depending on the tissue and disease model. In a murine model of allergic airway inflammation, we found that IL-22 is predominantly produced by innate lymphoid cells in the inflamed lungs, rather than TH cells. To determine the impact of IL-22 on airway inflammation, we used allergen-sensitized IL-22-deficient mice and found that they suffer from significantly higher airway hyperreactivity upon airway challenge. IL-22-deficiency led to increased eosinophil infiltration lymphocyte invasion and production of CCL17 (TARC), IL-5 and IL-13 in the lung. Mice treated with IL-22 before antigen challenge displayed reduced expression of CCL17 and IL-13 and significant amelioration of airway constriction and inflammation. We conclude that innate IL-22 limits airway inflammation, tissue damage and clinical decline in allergic lung disease.     

Insekten- und Windbestäubung beiAlisma plantago-aquatica L.

Ohne Zusammenfassung     

Assessing visual requirements for social context-dependent activation of the songbird song system

Social context has been shown to have a profound influence on brain activation in a wide range of vertebrate species. Best studied in songbirds, when males sing undirected song, the level of neural activity and expression of immediate early genes (IEGs) in several song nuclei is dramatically higher or lower than when they sing directed song to other birds, particularly females. This differential social context-dependent activation is independent of auditory input and is not simply dependent on the motor act of singing. These findings suggested that the critical sensory modality driving social context-dependent differences in the brain could be visual cues. Here, we tested this hypothesis by examining IEG activation in song nuclei in hemispheres to which visual input was normal or blocked. We found that covering one eye blocked visually induced IEG expression throughout both contralateral visual pathways of the brain, and reduced activation of the contralateral ventral tegmental area, a non-visual midbrain motivation-related area affected by social context. However, blocking visual input had no effect on the social context-dependent activation of the contralateral song nuclei during female-directed singing. Our findings suggest that individual sensory modalities are not direct driving forces for the social context differences in song nuclei during singing. Rather, these social context differences in brain activation appear to depend more on the general sense that another individual is present.     

Occurrence and social structure of Baird's beaked whales,Berardius bairdii,in the Commander Islands,Russia

The social structure of Baird's beaked whales is completely unstudied, and it is unknown if either females or males form long‐term social associations or occur in stable groups. In this paper we summarize our observations of individually identified animals over the span of 6 yr to provide insight on their long‐term social structure. We have identified 122 whales, with 28 of them encountered three times or more and thus included in the analysis of social structure. We found that the whales exhibited nonrandom patterns of social associations with some individuals preferentially associating with each other. Whales with more scarred skin had higher maximum association coefficients, which indicates that older animals and/or males were more inclined to form stable associations. Cluster analysis with a modularity test for gregariousness divided the whales into four clusters. Whales from the same clusters did not always occur together, but some individuals retained stable associations over several years. The strength of social relationships decayed over periods of months, with between‐year relationships showing little deviation from what would be expected if association was random. Generally these findings do not correspond to a stable society with fixed groups but instead suggest a fission‐fusion society with some stable alliances.     

Zur Taxonomie und Chorologie der Gattung Scopolia Jacq.

At the present time 5 species of the genus Scopolia Jacq. are demonstrating the close relations between the distribution patterns, situations and ecology of plants. They are growing recently in broadleaved deciduous forests and mixed forests with a different part of evergreen trees, shrubs and perennial herbs. Hyoscyamus L., a genus of Hyoscyaminae has become adapted to increasing aridity and shows now a center of distribution in the mountains of the eastern Mediterranean area and Near East within a semiarid climate on the western side of Eurasia. Scopolia Jacq. may be judged as relictic genus of mixed Tertiary broadleaved forest with a special evolution center on the eastside of the Eurasian continent under humid monsoon conditions. The recent scattered and disjunct distribution with gaps in arid-semiarid areas indicates the result of a long way of plantevolution, plant dispersal and changable history of the vegetation. The important, climatical conditions for the growth of Scopolia species are sufficient rainfall and moisture in summertime. Chill and frost in winter were forcing these herbs in temperate and northern regions to survive in superficial strata of the soils.