570 Biowissenschaften; Biologie
Refine
Has Fulltext
- yes (24)
Year of publication
- 2013 (24) (remove)
Document Type
- Doctoral Thesis (15)
- Postprint (9)
Language
- English (24) (remove)
Keywords
- Proteom (2)
- arbuscular mycorrhizal symbiosis (2)
- phosphorylation (2)
- probiotics (2)
- Allozymes (1)
- Anoxie (1)
- Antimikrobielle Peptide (1)
- Approximate Bayesian Computation (1)
- Arctic (1)
- Arktis (1)
- Ausbreitung (1)
- BMI (1)
- Bimolecular Reaction (1)
- Breast cancer (1)
- Brownification (1)
- Brustkrebs (1)
- Carbon Cycling (1)
- Carbon cycling (1)
- Cell proliferation (1)
- DNA cleavage (1)
- Darmbakterien (1)
- Darmlänge (1)
- Diversität (1)
- E. coli (1)
- Ecology (1)
- Ecotoxicology (1)
- Enterolignanen (1)
- Enterolignans (1)
- Ernährungsfaktoren (1)
- Escherichia coli (1)
- Fano Factor (1)
- Fragmentierung (1)
- Gene Regulatory Network (1)
- Glykogen (1)
- IBD (1)
- Ivy (1)
- Kohlenstoff (1)
- Kurzkettige Fettsäuren (1)
- Körperbautyp (1)
- Körperfett (1)
- Lafora disease (1)
- Lignan-converting bacteria (1)
- Lignan-umwandelnde Bakterien (1)
- Lipide (1)
- Medicago truncatula (1)
- Mediterranean Sea (1)
- Methan (1)
- Microsatellites (1)
- Mikrobiologie (1)
- Mikrobiota (1)
- Mitochondrial DNA (1)
- Monoschichten (1)
- NMR (1)
- Orchestia montagui (1)
- OxyR (1)
- POL (1)
- PRM/Alf Maus (1)
- PRM/Alf mouse (1)
- Peptid-Membran-Wechselwirkung (1)
- Permafrost (1)
- Pflanzengemeinschaften (1)
- Pflanzliches Lignan (1)
- Phosphorylierung (1)
- Phylogeography (1)
- Plant lignan (1)
- Polyamine (1)
- Populationsdynamik (1)
- Primärproduktion (1)
- Probiotika (1)
- Reaction Rate Constant (1)
- Rhizophagus irregularis (1)
- Skeletal robustness (1)
- Skelettrobustizität (1)
- Stochastic Simulation (1)
- Stärke (1)
- Talitrids (1)
- Transkriptionsfaktoren (1)
- Transkriptom Sequenzierung (1)
- Transkriptomanalyse (1)
- Zellmembranen (1)
- Zellproliferation (1)
- Zelltyp-spezifisch (1)
- Zuckertransporter (1)
- amp (1)
- animal personalities (1)
- anoxia (1)
- antimicrobial peptides (1)
- apoptosis (1)
- arbuskuläre Mykorrhiza-Symbiose (1)
- arbuskuläre Mykorrhizasymbiose (1)
- behavioural adaptations (1)
- biodiversity conservation (1)
- boldness (1)
- brownification (1)
- burrow system (1)
- carbon (1)
- carbon flow (1)
- cell type-specific (1)
- chemoattractant (1)
- chemotaxis (1)
- chronic and acute inflammation (1)
- chronisch-entzündliche Darmerkrankungen (1)
- codon usage (1)
- cohesive ends (1)
- commensal (1)
- common vole (1)
- community dynamics (1)
- cyclic-gmp (1)
- cytokines (1)
- cytoskeleton (1)
- dictyostelium-discoideum (1)
- dietary factors (1)
- dispersal (1)
- diversity (1)
- ecological modelling (1)
- ena/vasp proteins (1)
- faecal corticosterone metabolites (1)
- fragmentation (1)
- functional annotation (1)
- gene family (1)
- gene ontology (1)
- genetic vectors (1)
- glycogen (1)
- goblet cells (1)
- gut length (1)
- gut microbiota (1)
- immune response (1)
- individual based modeling (1)
- infection (1)
- inflammatory bowel disease (1)
- interspecific interactions (1)
- körperliche Bewegung (1)
- landscape genetics (1)
- life history (1)
- lipids (1)
- long distance movement (1)
- mRNA structure (1)
- membranes (1)
- metabolism (1)
- methane (1)
- microbiology (1)
- microbiota (1)
- mobile links (1)
- modified primers (1)
- molecular methods (1)
- monolayer (1)
- mucus (1)
- nest predation (1)
- oscillations (1)
- osmotic-stress (1)
- pace-of-life (1)
- pathogen (1)
- peptide-membrane-interaction (1)
- percentage of body fat (1)
- phenotypic plasticity (1)
- physical activity (1)
- plant communities (1)
- polyamines (1)
- polymerase chain reaction (1)
- population dynamics (1)
- primary production (1)
- proteome (1)
- proteomics (1)
- qualitative pathway interpretation (1)
- recombinant Escherichia coli (1)
- reference database (1)
- reference proteomes (1)
- restriction enzymes (1)
- short chain fatty acids (1)
- shrews (1)
- small mammals (1)
- somatotype (1)
- species coexistence (1)
- stable isotope tracing (1)
- starch (1)
- stress response (1)
- sucrose (1)
- sugar transporter (1)
- transcription factors (1)
- transcriptome analysis (1)
- transcriptome sequencing (1)
- translation (1)
- voles (1)
- Ökologie (1)
- Ökotoxikologie (1)
- ökologische Modellierung (1)
For the first time the transcriptional reprogramming of distinct root cortex cells during the arbuscular mycorrhizal (AM) symbiosis was investigated by combining Laser Capture Mirodissection and Affymetrix GeneChip® Medicago genome array hybridization. The establishment of cryosections facilitated the isolation of high quality RNA in sufficient amounts from three different cortical cell types. The transcript profiles of arbuscule-containing cells (arb cells), non-arbuscule-containing cells (nac cells) of Rhizophagus irregularis inoculated Medicago truncatula roots and cortex cells of non-inoculated roots (cor) were successfully explored. The data gave new insights in the symbiosis-related cellular reorganization processes and indicated that already nac cells seem to be prepared for the upcoming fungal colonization. The mycorrhizal- and phosphate-dependent transcription of a GRAS TF family member (MtGras8) was detected in arb cells and mycorrhizal roots. MtGRAS shares a high sequence similarity to a GRAS TF suggested to be involved in the fungal colonization processes (MtRAM1). The function of MtGras8 was unraveled upon RNA interference- (RNAi-) mediated gene silencing. An AM symbiosis-dependent expression of a RNAi construct (MtPt4pro::gras8-RNAi) revealed a successful gene silencing of MtGras8 leading to a reduced arbuscule abundance and a higher proportion of deformed arbuscules in root with reduced transcript levels. Accordingly, MtGras8 might control the arbuscule development and life-time. The targeting of MtGras8 by the phosphate-dependent regulated miRNA5204* was discovered previously (Devers et al., 2011). Since miRNA5204* is known to be affected by phosphate, the posttranscriptional regulation might represent a link between phosphate signaling and arbuscule development. In this work, the posttranscriptional regulation was confirmed by mis-expression of miRNA5204* in M. truncatula roots. The miRNA-mediated gene silencing affects the MtGras8 transcript abundance only in the first two weeks of the AM symbiosis and the mis-expression lines seem to mimic the phenotype of MtGras8-RNAi lines. Additionally, MtGRAS8 seems to form heterodimers with NSP2 and RAM1, which are known to be key regulators of the fungal colonization process (Hirsch et al., 2009; Gobbato et al., 2012). These data indicate that MtGras8 and miRNA5204* are linked to the sym pathway and regulate the arbuscule development in phosphate-dependent manner.
The genetic code is degenerate; thus, protein evolution does not uniquely determine the coding sequence. One of the puzzles in evolutionary genetics is therefore to uncover evolutionary driving forces that result in specific codon choice. In many bacteria, the first 5-10 codons of protein-coding genes are often codons that are less frequently used in the rest of the genome, an effect that has been argued to arise from selection for slowed early elongation to reduce ribosome traffic jams. However, genome analysis across many species has demonstrated that the region shows reduced mRNA folding consistent with pressure for efficient translation initiation. This raises the possibility that unusual codon usage is a side effect of selection for reduced mRNA structure. Here we discriminate between these two competing hypotheses, and show that in bacteria selection favours codons that reduce mRNA folding around the translation start, regardless of whether these codons are frequent or rare. Experiments confirm that primarily mRNA structure, and not codon usage, at the beginning of genes determines the translation rate.
Background: DNA fragments carrying internal recognition sites for the restriction endonucleases intended for cloning into a target plasmid pose a challenge for conventional cloning.
Results: A method for directional insertion of DNA fragments into plasmid vectors has been developed. The target sequence is amplified from a template DNA sample by PCR using two oligonucleotides each containing a single deoxyinosine base at the third position from the 5' end. Treatment of such PCR products with endonuclease V generates 3' protruding ends suitable for ligation with vector fragments created by conventional restriction endonuclease reactions.
Conclusions: The developed approach generates terminal cohesive ends without the use of Type II restriction endonucleases, and is thus independent from the DNA sequence. Due to PCR amplification, minimal amounts of template DNA are required. Using the robust Taq enzyme or a proofreading Pfu DNA polymerase mutant, the method is applicable to a broad range of insert sequences. Appropriate primer design enables direct incorporation of terminal DNA sequence modifications such as tag addition, insertions, deletions and mutations into the cloning strategy. Further, the restriction sites of the target plasmid can be either retained or removed.
Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells
(2013)
Cyclic GMP (cGMP) is a ubiquitous second messenger in eukaryotic cells. It is assumed to regulate the association of myosin II with the cytoskeleton of motile cells. When cells of the social amoeba Dictyostelium discoideum are exposed to chemoattractants or to increased osmotic stress, intracellular cGMP levels rise, preceding the accumulation of myosin II in the cell cortex. To directly investigate the impact of intracellular cGMP on cytoskeletal dynamics in a living cell, we released cGMP inside the cell by laser-induced photo-cleavage of a caged precursor. With this approach, we could directly show in a live cell experiment that an increase in intracellular cGMP indeed induces myosin II to accumulate in the cortex. Unexpectedly, we observed for the first time that also the amount of filamentous actin in the cell cortex increases upon a rise in the cGMP concentration, independently of cAMP receptor activation and signaling. We discuss our results in the light of recent work on the cGMP signaling pathway and suggest possible links between cGMP signaling and the actin system.