423 research outputs found
E+E-Projekt „Integration von Naturschutzzielen in den Ökologischen Landbau am Beispiel der Hessischen Staatsdomäne Frankenhausen“ - Maßnahmen zur Entwicklung dauerhafter Landschaftsstrukturen
The Hessian state domain Frankenhausen near Kassel was converted to organic farming in July 1998 and serves as a research and demonstration farm of the univer-sity. Before that time the farm changed constantly by typical intensification of conven-tional farming: The landscape is a mirror of intense use: cleared and drained fields, canalised brooks and large fields with few structural elements. – Within the project “The Integration of Nature Conservation into Organic Farming” (supported by the German Federal Agency for Nature Conservation with funds from the Federal Envi-ronmental Ministry) and based on the analysis of the present situation using methods of landscape ecology. Measures to restore brooks, structural elements and biotopes are to be implemented. The aim is to integrate structural elements like hedgerows into the farm management
Tension in Skinned Frog Muscle Fibers in Solutions of Varying Ionic Strength and Neutral Salt Composition
Assembly, Gene Annotation and Marker Development Using 454 Floral Transcriptome Sequences in Ziziphus Celata (Rhamnaceae), a Highly Endangered, Florida Endemic Plant
Large-scale DNA sequence data may enable development of genetic resources in endangered species, thereby facilitating conservation efforts. Ziziphus celata, a federally endangered, self-incompatible plant species occurring in Florida, USA, is one species for which genetic resources are necessary to facilitate new introductions and augmentations essential for recovery of the species. We used 454 pyrosequencing of a Z. celata normalized floral cDNA library to create a genomic resource for gene and marker discovery. A half-plate GS-FLX Titanium run yielded 655 337 reads averaging 250 bp. A total of 474 025 reads were assembled de novo into 84 645 contigs averaging 408 bp, while 181 312 reads remained unassembled. Forty-seven and 43% of contig consensus sequences had BLAST matches to known proteins in the Uniref50 and TAIR9 annotated protein databases, respectively; many contigs fully represented orthologous proteins in TAIR9. A total of 22 707 unique genes were sequenced, indicating substantial coverage of the Z. celata transcriptome. We detected single-nucleotide polymorphisms and simple sequence repeats (SSRs) and developed thousands of SSR primers for use in future genetic studies. As a first step towards understanding self-incompatibility in Z. celata, we identified sequences belonging to the gene family encoding self-incompatibility. This study demonstrates the efficacy of 454 transcriptome sequencing for rapid gene and marker discovery in an endangered plant
Recurrent Modification of a Conserved Cis-Regulatory Element Underlies Fruit Fly Pigmentation Diversity
The development of morphological traits occurs through the collective action of networks of genes connected at the level of gene expression. As any node in a network may be a target of evolutionary change, the recurrent targeting of the same node would indicate that the path of evolution is biased for the relevant trait and network. Although examples of parallel evolution have implicated recurrent modification of the same gene and cis-regulatory element (CRE), little is known about the mutational and molecular paths of parallel CRE evolution. In Drosophila melanogaster fruit flies, the Bric-à-brac (Bab) transcription factors control the development of a suite of sexually dimorphic traits on the posterior abdomen. Female-specific Bab expression is regulated by the dimorphic element, a CRE that possesses direct inputs from body plan (ABD-B) and sex-determination (DSX) transcription factors. Here, we find that the recurrent evolutionary modification of this CRE underlies both intraspecific and interspecific variation in female pigmentation in the melanogaster species group. By reconstructing the sequence and regulatory activity of the ancestral Drosophila melanogaster dimorphic element, we demonstrate that a handful of mutations were sufficient to create independent CRE alleles with differing activities. Moreover, intraspecific and interspecific dimorphic element evolution proceeded with little to no alterations to the known body plan and sex-determination regulatory linkages. Collectively, our findings represent an example where the paths of evolution appear biased to a specific CRE, and drastic changes in function were accompanied by deep conservation of key regulatory linkages. © 2013 Rogers et al
Validating the Eating Disorder Inventory-3 (EDI-3): A Comparison Between 561 Female Eating Disorders Patients and 878 Females from the General Population
The Eating Disorder Inventory (EDI) is used worldwide in research and clinical work. The 3rd version (EDI-3) has been used in recent research, yet without any independent testing of its psychometric properties. The aim of the present study was twofold: 1) to establish national norms and to compare them with the US and international norms, and 2) to examine the factor structure, the internal consistency, the sensitivity and the specificity of subscale scores. Participants were Danish adult female patients (N = 561) from a specialist treatment centre and a control group (N = 878) was women selected from the Danish Civil Registration system. Small but significant differences were found between Danish and international, as well as US norms. Overall, the factor structure was confirmed, the internal consistency of the subscales was satisfactory, the discriminative validity was good, and sensitivity and specificity were excellent. The implications from these results are discussed
The NEMP family supports metazoan fertility and nuclear envelope stiffness.
Human genome-wide association studies have linked single-nucleotide polymorphisms (SNPs) in NEMP1 (nuclear envelope membrane protein 1) with early menopause; however, it is unclear whether NEMP1 has any role in fertility. We show that whole-animal loss of NEMP1 homologs in Drosophila, Caenorhabditis elegans, zebrafish, and mice leads to sterility or early loss of fertility. Loss of Nemp leads to nuclear shaping defects, most prominently in the germ line. Biochemical, biophysical, and genetic studies reveal that NEMP proteins support the mechanical stiffness of the germline nuclear envelope via formation of a NEMP-EMERIN complex. These data indicate that the germline nuclear envelope has specialized mechanical properties and that NEMP proteins play essential and conserved roles in fertility
Contrasting Patterns of Sequence Evolution at the Functionally Redundant bric à brac Paralogs in Drosophila melanogaster
Genes with overlapping expression and function may gradually diverge despite retaining some common functions. To test whether such genes show distinct patterns of molecular evolution within species, we examined sequence variation at the bric à brac (bab) locus of Drosophila melanogaster. This locus is composed of two anciently duplicated paralogs, bab1 and bab2, which are involved in patterning the adult abdomen, legs, and ovaries. We have sequenced the 148 kb genomic region spanning the bab1 and bab2 genes from 94 inbred lines of D. melanogaster sampled from a single location. Two non-coding regions, one in each paralog, appear to be under selection. The strongest evidence of directional selection is found in a region of bab2 that has no known functional role. The other region is located in the bab1 paralog and is known to contain a cis-regulatory element that controls sex-specific abdominal pigmentation. The coding region of bab1 appears to be under stronger functional constraint than the bab2 coding sequences. Thus, the two paralogs are evolving under different selective regimes in the same natural population, illuminating the different evolutionary trajectories of partially redundant duplicate genes
Mechanical and kinetic effects of shortened tropomyosin reconstituted into myofibrils
The effects of tropomyosin on muscle mechanics and kinetics were examined in skeletal myofibrils using a novel method to remove tropomyosin (Tm) and troponin (Tn) and then replace these proteins with altered versions. Extraction employed a low ionic strength rigor solution, followed by sequential reconstitution at physiological ionic strength with Tm then Tn. SDS-PAGE analysis was consistent with full reconstitution, and fluorescence imaging after reconstitution using Oregon-green-labeled Tm indicated the expected localization. Myofibrils remained mechanically viable: maximum isometric forces of myofibrils after sTm/sTn reconstitution (control) were comparable (~84%) to the forces generated by non-reconstituted preparations, and the reconstitution minimally affected the rate of isometric activation (kact), calcium sensitivity (pCa50), and cooperativity (nH). Reconstitutions using various combinations of cardiac and skeletal Tm and Tn indicated that isoforms of both Tm and Tn influence calcium sensitivity of force development in opposite directions, but the isoforms do not otherwise alter cross-bridge kinetics. Myofibrils reconstituted with Δ23Tm, a deletion mutant lacking the second and third of Tm’s seven quasi-repeats, exhibited greatly depressed maximal force, moderately slower kact rates and reduced nH. Δ23Tm similarly decreased the cooperativity of calcium binding to the troponin regulatory sites of isolated thin filaments in solution. The mechanisms behind these effects of Δ23Tm also were investigated using Pi and ADP jumps. Pi and ADP kinetics were indistinguishable in Δ23Tm myofibrils compared to controls. The results suggest that the deleted region of tropomyosin is important for cooperative thin filament activation by calcium
Effect of phosphate and temperature on force exerted by white muscle fibres from dogfish.
Effects of Pi (inorganic phosphate) are relevant to the in vivo function of muscle because Pi is one of the products of ATP hydrolysis by actomyosin and by the sarcoplasmic reticulum Ca pump. We have measured the Pi sensitivity of force produced by permeabilized muscle fibres from dogfish (Scyliorhinus canicula) and rabbit. The activation conditions for dogfish fibres were crucial: fibres activated from the relaxed state at 5, 12, and 20°C were sensitive to Pi, whereas fibres activated from rigor at 12°C were insensitive to Pi in the range 5-25 mmol l. Rabbit fibres activated from rigor were sensitive to Pi. Pi sensitivity of force produced by dogfish fibres activated from the relaxed state was greater below normal body temperature (12°C for dogfish) in agreement with what is known for other species. The force-temperature relationship for dogfish fibres (intact and permeabilized fibres activated from relaxed) showed that at 12°C, normal body temperature, the force was near to its maximum value
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