Matriline effects on metamorphic traits in a natural system in the European common frog (Rana temporaria)

Successful reproduction is an important determinant of the fitness of an individual and of the dynamics of populations. Offspring of the European common frog (Rana temporaria) exhibit a high degree of variability in metamorphic traits. However, environmental factors alone cannot explain this phenotypic variability, and the influence of genetic factors remains to be determined. Here, we tested whether the maternal genotype influences developmental time, body size, and body condition of offspring in a forest pond in Germany. We collected fertilized eggs from all 57 clutches deposited in the pond. We used multilocus genotypes based on seven microsatellite loci to assign metamorphosed offspring to mothers and to determine the number of fathers for a single matriline. We tested the influence of genetic effects in the same environment by comparing variability of metamorphic traits within and between full‐sib offspring grouped to matrilines and tested whether multiple paternity increases the variability of metamorphic traits in a single matriline. The variability in size and body condition was higher within matrilines than between them, which indicates that these traits are more strongly influenced by environmental effects, which are counteracting underlying genetic effects. The developmental time varied considerably between matrilines and variability increased with the effective number of fathers, suggesting an additive genetic effect of multiple paternity. Our results show that metamorphic traits are shaped by environmental as well as genetic effects.     

Marine extinction risk shaped by trait–environment interactions over 500 million years

Perhaps the most pressing issue in predicting biotic responses to present and future global change is understanding how environmental factors shape the relationship between ecological traits and extinction risk. The fossil record provides millions of years of insight into how extinction selectivity (i.e., differential extinction risk) is shaped by interactions between ecological traits and environmental conditions. Numerous paleontological studies have examined trait‐based extinction selectivity; however, the extent to which these patterns are shaped by environmental conditions is poorly understood due to a lack of quantitative synthesis across studies. We conducted a meta‐analysis of published studies on fossil marine bivalves and gastropods that span 458 million years to uncover how global environmental and geochemical changes covary with trait‐based extinction selectivity. We focused on geographic range size and life habit (i.e., infaunal vs. epifaunal), two of the most important and commonly examined predictors of extinction selectivity. We used geochemical proxies related to global climate, as well as indicators of ocean acidification, to infer average global environmental conditions. Life‐habit selectivity is weakly dependent on environmental conditions, with infaunal species relatively buffered from extinction during warmer climate states. In contrast, the odds of taxa with broad geographic ranges surviving an extinction (>2500 km for genera, >500 km for species) are on average three times greater than narrow‐ranging taxa (estimate of odds ratio: 2.8, 95% confidence interval = 2.3–3.5), regardless of the prevailing global environmental conditions. The environmental independence of geographic range size extinction selectivity emphasizes the critical role of geographic range size in setting conservation priorities.     

Artenschwund trotz Naturschutz

Species loss despite nature conservation: need for action and research About 40 per cent of all plant and animal species occurring in Germany (insects, mammals, fish, birds, amphibians and reptiles) are endangered or threatened with extinction; 3–4 per cent are already considered lost. A comparison with other European countries shows that the risk situation in Germany is also very serious from an international point of view. In order to better anchor nature conservation in modern society as a prerequisite for globally sustainable development, it is necessary (1) to rethink and change the actions of each individual through education, communication and discussion; (2) to refocus policy and existing funding instruments; (3) to strengthen biodiversity and nature conservation concerns in and through universities and colleges, and (4) to invest in nature conservation in order to preserve nature as the basis of human life (ecosystem services) and on account of its intrinsic value. Conservation must be economically viable. This should not only be the case for farmers, but also for any land use that meets the requirements of nature conservation. Any conservation effort should be rewarded. To ensure that the actually set and clearly defined objectives of the EU nature conservation directives can be achieved, the Federal Working Group on Nature Conservation, Landscape Conservation and Recreation (LANA) predicts that at least 1.4 billion euros additionally will be needed annually. This would correspond to about 17 euros per inhabitant and year. This comparatively small amount would more than double the budget available in Germany for the protection of biodiversity.     

CyaC,a redox‐regulated adenylate cyclase of Sinorhizobium meliloti with a quinone responsive diheme‐B membrane anchor domain

The nucleotide cyclase CyaC of Sinorhizobium meliloti is a member of class III adenylate cyclases (AC), a diverse group present in all forms of life. CyaC is membrane‐integral by a hexahelical membrane domain (6TM) with the basic topology of mammalian ACs. The 6TM domain of CyaC contains a tetra‐histidine signature that is universally present in the membrane anchors of bacterial diheme‐B succinate‐quinone oxidoreductases. Heterologous expression of cyaC imparted activity for cAMP formation from ATP to Escherichia coli, whereas guanylate cyclase activity was not detectable. Detergent solubilized and purified CyaC was a diheme‐B protein and carried a binuclear iron‐sulfur cluster. Single point mutations in the signature histidine residues caused loss of heme‐B in the membrane and loss of AC activity. Heme‐B of purified CyaC could be oxidized or reduced by ubiquinone analogs (Q₀ or Q₀H₂). The activity of CyaC in bacterial membranes responded to oxidation or reduction by Q₀ and O₂, or NADH and Q₀H₂ respectively. We conclude that CyaC‐like membrane anchors of bacterial ACs can serve as the input site for chemical stimuli which are translated by the AC into an intracellular second messenger response.     

Isolation and characterization of bone marrow-derived mesenchymal progenitor cells with myogenic and neuronal properties

Sphere formation has been utilized as a way to isolate multipotent stem/progenitor cells from various tissues. However, very few studies on bone marrow-derived spheres have been published and assessed their multipotentiality. In this study, multipotent marrow cell populations were isolated using a three-step method. First, after elimination of hematopoietic cells, murine marrow-derived adherent cells were cultured in plastic dishes until small cells gradually appeared and multiplied. Cells were then cultured under non-adherent conditions and formed spheres that were immunopositive for a neural precursor marker, nestin. RT-PCR analysis also revealed that the spheres were positive for nestin in addition to PPARgamma, osf2, SOX9, and myoD, which are markers of precursors of adipocytic, osteoblastic, chondrocytic, and skeletal myeloblastic lineages, respectively. Finally, spheres were dissociated into single cells and expanded in adherent cultures. Under appropriate induction conditions, the sphere-derived cells acquired the phenotypic properties in vitro of neurons, skeletal myoblasts, and beating cardiomyocytes, as well as adipocytes, osteoblasts, and chondrocytes. Next, sphere-derived cells were transplanted into murine myocardial infarction models. One month later, they had become engrafted as cardiomyocytes, and cardiac catheterization showed significant functional improvements. Thus, sphere-derived cells represent a new approach to enhance the multi-differentiation potential of murine bone marrow.     

Identification of the genetic basis for complex disorders by use of pooling-based genomewide single-nucleotide-polymorphism association studies

We report the development and validation of experimental methods, study designs, and analysis software for pooling-based genomewide association (GWA) studies that use high-throughput single-nucleotide-polymorphism (SNP) genotyping microarrays. We first describe a theoretical framework for establishing the effectiveness of pooling genomic DNA as a low-cost alternative to individually genotyping thousands of samples on high-density SNP microarrays. Next, we describe software called "GenePool," which directly analyzes SNP microarray probe intensity data and ranks SNPs by increased likelihood of being genetically associated with a trait or disorder. Finally, we apply these methods to experimental case-control data and demonstrate successful identification of published genetic susceptibility loci for a rare monogenic disease (sudden infant death with dysgenesis of the testes syndrome), a rare complex disease (progressive supranuclear palsy), and a common complex disease (Alzheimer disease) across multiple SNP genotyping platforms. On the basis of these theoretical calculations and their experimental validation, our results suggest that pooling-based GWA studies are a logical first step for determining whether major genetic associations exist in diseases with high heritability.     

Targeted deletion of genes encoding extracellular enzymes in Bacillus licheniformis and the impact on the secretion capability

The general secretory pathway is routinely concerned with a multitude of extracellular enzymes. By eliminating obstructive competitors the export machinery may transport larger quantities of remaining proteins under circumstances in which the secretion machinery is fully loaded. Hence, in this study, genes encoding efficiently expressed but dispensable exoenzymes were knocked out in Bacillus licheniformis MD1. Single, double, and triple mutants with deletions of celA, chiA, and amyB, respectively, were generated via in vivo recombination by making use of a vector with a temperature sensitive origin of replication. Overexpression of a heterologous amylase gene on a multi-copy plasmid, a common scenario in biotechnological processes, resulted in an articulate reduction of chromosomally encoded extracellular enzyme activities indicating that the secretion machinery works to capacity in such transformants. Deletion mutants with the expression plasmid displayed enhanced amylase activities compared to the strain with the wild type genetic background. In addition, the chromosomally encoded protease activity was clearly higher in transformants with deletions.     

Targeted deletion of the <Emphasis Type="Italic">uvrBA</Emphasis> operon and biological containment in the industrially important <Emphasis Type="Italic">Bacillus licheniformis</Emphasis>

From a Bacillus licheniformis wild type as well as a defined asporogenous derivative, stable UV hypersensitive mutants were generated by targeted deletion of the uvrBA operon, encoding highly conserved key components of the nucleotide excision repair. Comparative studies, which included the respective parental strains, revealed no negative side effects of the deletion, neither on enzyme secretion nor on vegetative propagation. Thus, the uvrBA locus proved to be a useful deletion target for achieving biological containment in this industrially exploited bacterium. In contrast to recA mutants, which also display UV hypersensitivity, further strain development via homologous recombination techniques will be still possible in such uvr mutants.