812 research outputs found
KulcsfontossĂĄgĂș gĂ©nek genomikai elĆrejelzĂ©se: In Silico megközelĂtĂ©s = Genomic prediction of essential genes: in silico approach
KulcsfontossĂĄgĂș gĂ©nek bioinformatikai elemzĂ©se: Csoportunk szĂĄmos szĂĄmos olyan sajĂĄtsĂĄgot ismertek fel, melyek segĂtsĂ©gĂ©vel jellemezni lehet az esszenciĂĄlis vagy a gĂ©ndĂłzis vĂĄltozĂĄsĂĄra Ă©rzĂ©keny gĂ©neket. Ezek közĂŒl a gĂ©nduplikĂĄciĂłt, az alternatĂv anyagcsereĂștvonalak jelenlĂ©tĂ©t, a gĂ©nkifejezĆdĂ©s mĂ©rtĂ©kĂ©t Ă©s a gĂ©n genomon belĂŒli pozĂciĂłjĂĄt Ă©rdemes megemlĂteni. RendszerbiolĂłgiai modellek alapjĂĄn kulcsfontossĂĄgĂș metabolikus gĂ©nek elĆrejelzĂ©se: ElĆzetesen leĂrt mĂłdszerekre alapozva, rĂ©szletes vizsgĂĄlatnak vetettĂŒk alĂĄ a sörĂ©lesztĆ rekonstruĂĄlt metabolikus hĂĄlĂłzatĂĄt, majd megvizsgĂĄltuk, hogyan viselkedik a rendszer ha egy-egy enzim mƱködĂ©skĂ©ptelen. MĂłdszerĂŒnk sikeresen jelzi elĆre az esszenciĂĄlis gĂ©nek 85%-ĂĄt. Ez a siker lehetĆvĂ© tette, hogy a biolĂłgia olyan kulcskĂ©rdĂ©seire keressĂŒnk vĂĄlaszt, mint a mutĂĄciĂłkkal szembeni robusztussĂĄg hĂĄttere, a biolĂłgiai hĂĄlĂłzatok evolĂșciĂłs vĂĄltozĂĄsa vagy a minimĂĄl genomok termĂ©szete. Genetikai interakciĂłk rendszerbiolĂłgiai Ă©s kĂsĂ©rleti vizsgĂĄlata: AnyagcserehĂĄlĂłzat rendszerbiolĂłgiai modellĂŒnk komoly lehetĆsĂ©get biztosĂt a genetikai interakciĂłk mĂ©lyebb megĂ©rtĂ©sĂ©hez. A modell sikeresen kĂ©pes elĆrejelezni speciĂĄlis genetikai interakciĂłk jelenlĂ©tĂ©t. SzĂĄmos Ă©rvĂŒnk szĂłl amelett, hogy a mutĂĄciĂłkkal szembeni robusztussĂĄg a kĂŒlönbözĆ környezeti feltĂ©telekhez valĂł alkalmazkodĂĄs mellĂ©ktermĂ©ke. | Bioinformatics analyses of essential genes: We identified several cellular and genomic features that enable reliable characterization of essential and dosage sensitive genes: Gene duplication, alternative metabolic pathways, gene expression level and genomic position all have some effect on gene dispensability. In silico prediction of essential metabolic genes using systems biological models: We have employed and further developed a previously elaborated metabolic network model of yeast. Our method predicts gene essentiality with about 85% accuracy. These methods have enabled us to study several key issues in evolutionary biology, such as the nature of mutational robustness and minimal genomes or the driving forces in the evolution of metabolic networks. Computational and experimental analyses of genetic interactions: The computational model described above paves the way for gaining novel insights into the nature of genetic interactions. The current model is able to predict the presence of genetic interactions in the metabolic networks of yeast with nearly 50% accuracy, while only approximately 0.5% would be expected by chance. Along with other arguments, our findings suggest that apparent robustness against harmful mutations is not a directly selected trait, but it's rather a by-product of organismal adaptation to varying environments
Integration of Horizontally Transferred Genes into Regulatory Interaction Networks Takes Many Million Years
Adaptation of bacteria to new or changing environments is often associated with the uptake of foreign genes through horizontal gene transfer. However, it has remained unclear how (and how fast) new genes are integrated into their host's cellular networks. Combining the regulatory and protein interaction networks of Escherichia coli with comparative genomics tools, we provide the first systematic analysis of this issue. Genes transferred recently have fewer interaction partners compared to nontransferred genes in both regulatory and protein interaction networks. Thus, horizontally transferred genes involved in complex regulatory and protein-protein interactions are rarely favored by selection. Only few protein-protein interactions are gained after the initial integration of genes following the transfer event. In contrast, transferred genes are gradually integrated into the regulatory network of their host over evolutionary time. During adaptation to the host cellular environment, horizontally transferred genes recruit existing transcription factors of the host, reflected in the fast evolutionary rates of the cis-regulatory regions of transferred genes. Further, genes resulting from increasingly ancient transfer events show increasing numbers of transcriptional regulators as well as improved coregulation with interacting proteins. Fine-tuned integration of horizontally transferred genes into the regulatory network spans more than 8-22 million years and encompasses accelerated evolution of regulatory regions, stabilization of protein-protein interactions, and changes in codon usage
Polynomial Schur's theorem
We resolve the Ramsey problem for for all polynomials
over .Comment: 21 page
A vĂĄllalkozĂĄsok hatĂ©konysĂĄgi tartalĂ©kai a menedzsment terĂŒletĂ©n = Efficiency reserves of enterprises in management
A tanulmĂĄny arra a kĂ©rdĂ©sre keres vĂĄlaszt, hogy van-e lehetĆsĂ©g a versenykĂ©pessĂ©g fokozatos javĂtĂĄsĂĄra. Milyen tartalĂ©kokat lehet feltĂĄrni a GlobĂĄlis versenykĂ©pessĂ©gi jelentĂ©s tapasztalatainak ismeretĂ©ben, amelyek elĆsegĂthetik a hatĂ©konysĂĄg javulĂĄsĂĄn keresztĂŒl az erĆsebb versenypozĂciĂł visszaĂĄllĂtĂĄsĂĄt
Contribution to the mayfly, aquatic and semiaquatic bug, aquatic beetle, caddisfly and chironomid fauna of the River Tisza and its main inflows (Ephemeroptera, Heteroptera: Nepomorpha and Gerromorpha, Coleoptera: Hydradephaga and Hydrophiloidea, Trichoptera, Diptera: Chironomidae)
Localities and collecting data of 25 mayfly, 20 aquatic and semiaquatic bug, 49 aquatic beetle, 15 caddisfly
and 55 chironomid taxa are given from 26 collecting sites of the River Tisza and its main inflows. The
Helophorus arvernicus Mulsant, 1846 (Coleoptera: Helophoridae) is new to the Hungarian fauna
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