97 research outputs found
IT Projects Planning in a Selected Company
Import 04/11/2015Tato bakalářská práce se zabývá projektovým řízením v IT, konkrétně plánováním a řízením průběhu vzniku webových stránek (e-shopu) za pomocí agilní metodiky Scrum. Teoretická část se věnuje představení různých metod pro plánování projektů, pro řízení rizik a možnostem kontroly projektů. V další části je představena firma, ve které vznikala praktická část bakalářské práce, ve které byl sestaven projektový plán agilní metodikou Scrum, vykalkulována cena projektu pro zákazníka a závěrem jsou uvedeny návrhy a doporučení pro vybranou firmu, jak postupovat při takovýchto projektech.This bachelor thesis deals with project management in IT, specifically the planning and management throughout the creation of Web sites (e-shop) with using the Scrum methodology. The theoretical part deals with the presentation of various methods for project planning, risk management and control of projects. The next part is about the selected firm, in which originated the practical part of the thesis, in which was compiled project plan with Scrum methodology, calculated cost of the project for the customer and the conclusion are set out proposals and recommendations for the selected company to proceed with such projects.152 - Katedra podnikohospodářskádobř
The Role of Type VI Secretion System Effectors in Target Cell Lysis and Subsequent Horizontal Gene Transfer
Bacteria use type VI secretion systems (T6SSs) to manipulate host cells during pathogenesis or to kill competing bacteria, which, in some cases, increases horizontal gene transfer. These functions largely depend on T6SS regulation, dynamics, and the set of effectors that the system delivers into the target cells. Here, we show that Acinetobacter baylyi ADP1 assembles a highly dynamic T6SS capable of killing and lysing bacterial cells. T6SS function depends on conserved T6SS components as well as Acinetobacter-specific genes of unknown function. Five different effectors, encoded next to VgrG or PAAR proteins and their cognate immunity proteins, cause distinct changes in the prey cells, resulting in various degrees of their lysis. Prey lysis correlates with the rate of DNA transfer from prey to predator, suggesting that lytic effectors are required for efficient T6SS-dependent horizontal gene transfer in naturally competent bacteria
Type VI Secretion System and Its Effectors PdpC, PdpD, and OpiA Contribute to; Francisella; Virulence in Galleria mellonella Larvae
Francisella tularensis causes the deadly zoonotic disease tularemia in humans and is able to infect a broad range of organisms including arthropods, which are thought to play a major role in; Francisella; transmission. However, while mammalian; in vitro; and; in vivo; infection models are widely used to investigate; Francisella; pathogenicity, a detailed characterization of the major; Francisella; virulence factor, a noncanonical type VI secretion system (T6SS), in an arthropod; in vivo; infection model is missing. Here, we use Galleria mellonella larvae to analyze the role of the; Francisella; T6SS and its corresponding effectors in F. tularensis subsp.; novicida; virulence. We report that G. mellonella larvae killing depends on the functional T6SS and infectious dose. In contrast to other mammalian; in vivo; infection models, even one of the T6SS effectors PdpC, PdpD, or OpiA is sufficient to kill G. mellonella larvae, while sheath recycling by ClpB is dispensable. We further demonstrate that treatment by polyethylene glycol (PEG) activates; Francisella; T6SS in liquid culture and that this is independent of the response regulator PmrA. PEG-activated IglC secretion is dependent on T6SS structural component PdpB but independent of putative effectors PdpC, PdpD, AnmK, OpiB; 1; , OpiB; 2; , and OpiB; 3; . The results of larvae infection and secretion assay suggest that AnmK, a putative T6SS component with unknown function, interferes with OpiA-mediated toxicity but not with general T6SS activity. We establish that the easy-to-use G. mellonella larvae infection model provides new insights into the function of T6SS and pathogenesis of; Francisella;
Biocomputational prediction of small non-coding RNAs in Streptomyces
<p>Abstract</p> <p>Background</p> <p>The first systematic study of small non-coding RNAs (sRNA, ncRNA) in <it>Streptomyces </it>is presented. Except for a few exceptions, the <it>Streptomyces </it>sRNAs, as well as the sRNAs in other genera of the <it>Actinomyces </it>group, have remained unstudied. This study was based on sequence conservation in intergenic regions of <it>Streptomyces</it>, localization of transcription termination factors, and genomic arrangement of genes flanking the predicted sRNAs.</p> <p>Results</p> <p>Thirty-two potential sRNAs in <it>Streptomyces </it>were predicted. Of these, expression of 20 was detected by microarrays and RT-PCR. The prediction was validated by a structure based computational approach. Two predicted sRNAs were found to be terminated by transcription termination factors different from the Rho-independent terminators. One predicted sRNA was identified computationally with high probability as a <it>Streptomyces </it>6S RNA. Out of the 32 predicted sRNAs, 24 were found to be structurally dissimilar from known sRNAs.</p> <p>Conclusion</p> <p><it>Streptomyces </it>is the largest genus of <it>Actinomyces</it>, whose sRNAs have not been studied. The <it>Actinomyces </it>is a group of bacterial species with unique genomes and phenotypes. Therefore, in <it>Actinomyces</it>, new unique bacterial sRNAs may be identified. The sequence and structural dissimilarity of the predicted <it>Streptomyces </it>sRNAs demonstrated by this study serve as the first evidence of the uniqueness of <it>Actinomyces </it>sRNAs.</p
Assembly and Subcellular Localization of Bacterial Type VI Secretion Systems
Bacteria need to deliver large molecules out of the cytosol to the extracellular space or even across membranes of neighboring cells to influence their environment, prevent predation, defeat competitors, or communicate. A variety of protein-secretion systems have evolved to make this process highly regulated and efficient. The type VI secretion system (T6SS) is one of the largest dynamic assemblies in gram-negative bacteria and allows for delivery of toxins into both bacterial and eukaryotic cells. The recent progress in structural biology and live-cell imaging shows the T6SS as a long contractile sheath assembled around a rigid tube with associated toxins anchored to a cell envelope by a baseplate and membrane complex. Rapid sheath contraction releases a large amount of energy used to push the tube and toxins through the membranes of neighboring target cells. Because reach of the T6SS is limited, some bacteria dynamically regulate its subcellular localization to precisely aim at their targets and thus increase efficiency of toxin translocation
Abundance of bacterial Type VI secretion system components measured by targeted proteomics
The Type VI secretion system (T6SS) is important for bacterial competition as well as virulence in many Gram-negative bacteria and its dynamics and regulation varies significantly between species. To gain insights into the mechanisms regulating T6SS assembly, we apply targeted proteomics to determine the abundance of the key T6SS components in Vibrio cholerae, Pseudomonas aeruginosa and Acinetobacter baylyi. We show that while there are species specific exceptions, the abundance of most components is similar in all three bacteria and ranges from less than hundred to tens of thousands of copies per cell. The comparison of T6SS dynamics and protein abundance in V. cholerae grown under various conditions suggests that the critical component TssE and the secreted protein VasX are unstable and this diminishes T6SS assembly when protein synthesis is limited. Our quantitative analysis opens possibilities to build realistic models of T6SS assembly and to identify principles of T6SS regulation in various species
reComBat: Batch effect removal in large-scale, multi-source omics data integration
With the steadily increasing abundance of omics data produced all over the world, some-times decades apart and under vastly different experimental conditions residing in public databases, a crucial step in many data-driven bioinformatics applications is that of data integration. The challenge of batch effect removal for entire databases lies in the large number and coincide of both batches and desired, biological variation resulting in design matrix singularity. This problem currently cannot be solved by any common batch correction algorithm. In this study, we present reComBat , a regularised version of the empirical Bayes method to overcome this limitation. We demonstrate our approach for the harmonisation of public gene expression data of the human opportunistic pathogen Pseudomonas aeruginosa and study a several metrics to empirically demonstrate that batch effects are successfully mitigated while biologically meaningful gene expression variation is retained. reComBat fills the gap in batch correction approaches applicable to large scale, public omics databases and opens up new avenues for data driven analysis of complex biological processes beyond the scope of a single study
reComBat: batch-effect removal in large-scale multi-source gene-expression data integration
With the steadily increasing abundance of omics data produced all over the world under vastly different experimental conditions residing in public databases, a crucial step in many data-driven bioinformatics applications is that of data integration. The challenge of batch-effect removal for entire databases lies in the large number of batches and biological variation, which can result in design matrix singularity. This problem can currently not be solved satisfactorily by any common batch-correction algorithm.; We present; reComBat; , a regularized version of the empirical Bayes method to overcome this limitation and benchmark it against popular approaches for the harmonization of public gene-expression data (both microarray and bulkRNAsq) of the human opportunistic pathogen; Pseudomonas aeruginosa; . Batch-effects are successfully mitigated while biologically meaningful gene-expression variation is retained.; reComBat; fills the gap in batch-correction approaches applicable to large-scale, public omics databases and opens up new avenues for data-driven analysis of complex biological processes beyond the scope of a single study.; The code is available at https://github.com/BorgwardtLab/reComBat, all data and evaluation code can be found at https://github.com/BorgwardtLab/batchCorrectionPublicData.; Supplementary data are available at; Bioinformatics Advances; online
Comparisons of Two Proteomic Analyses of Non-Mucoid and Mucoid Pseudomonas aeruginosa Clinical Isolates from a Cystic Fibrosis Patient
Pseudomonas aeruginosa chronically infects the lungs of cystic fibrosis (CF) patients. The conditions in the CF lung appear to select for P. aeruginosa with advantageous phenotypes for chronic infection. However, the mechanisms that allow the establishment of this chronic infection have not been fully characterized. We have previously reported the transcriptional analysis of two CF isolates strains 383 and 2192. Strain 2192 is a mucoid, alginate overproducing strain whereas strain 383 is non-mucoid. Mucoid strains are associated with chronic infection of the CF lung and non-mucoid strains are the typical initially infecting isolates. To elucidate novel differences between these two strains, we employed two methods of shotgun proteomics: isobaric tags for relative and absolute quantitation (iTRAQ) and two-dimensional gel electrophoresis (2-DE). iTRAQ compares the amount of protein between samples and relies on protein abundance, while 2-DE gel electrophoresis depends on selection of separated protein spots. For both these methods, mass spectrometry was then used to identify proteins differentially expressed between the two strains. The compilation of these two proteomic methods along with Western blot analysis revealed proteins of the HSI-I operon of the type 6 secretion system, showed increased expression in 383 compared to 2192, confirming the our previous transcriptional analysis. Proteomic analysis of other proteins did not fully correlate with the transcriptome but other differentially expressed proteins are discussed. Also, differences were noted between the results obtained for the two proteomic techniques. These shotgun proteomic analyses identified proteins that had been predicted only through gene identification; we now refer to these as “proteins of unknown functions” since their existence has now been established however their functional characterization remains to be elucidated
Transcriptomic Identification of Iron-Regulated and Iron-Independent Gene Copies within the Heavily Duplicated Trichomonas vaginalis Genome
Gene duplication is an important evolutionary mechanism and no eukaryote has more duplicated gene families than the parasitic protist Trichomonas vaginalis. Iron is an essential nutrient for Trichomonas and plays a pivotal role in the establishment of infection, proliferation, and virulence. To gain insight into the role of iron in T. vaginalis gene expression and genome evolution, we screened iron-regulated genes using an oligonucleotide microarray for T. vaginalis and by comparative EST (expressed sequence tag) sequencing of cDNA libraries derived from trichomonads cultivated under iron-rich (+Fe) and iron-restricted (−Fe) conditions. Among 19,000 ESTs from both libraries, we identified 336 iron-regulated genes, of which 165 were upregulated under +Fe conditions and 171 under −Fe conditions. The microarray analysis revealed that 195 of 4,950 unique genes were differentially expressed. Of these, 117 genes were upregulated under +Fe conditions and 78 were upregulated under −Fe conditions. The results of both methods were congruent concerning the regulatory trends and the representation of gene categories. Under +Fe conditions, the expression of proteins involved in carbohydrate metabolism, particularly in the energy metabolism of hydrogenosomes, and in methionine catabolism was increased. The iron–sulfur cluster assembly machinery and certain cysteine proteases are of particular importance among the proteins upregulated under −Fe conditions. A unique feature of the T. vaginalis genome is the retention during evolution of multiple paralogous copies for a majority of all genes. Although the origins and reasons for this gene expansion remain unclear, the retention of multiple gene copies could provide an opportunity to evolve differential expression during growth in variable environmental conditions. For genes whose expression was affected by iron, we found that iron influenced the expression of only some of the paralogous copies, whereas the expression of the other paralogs was iron independent. This finding indicates a very stringent regulation of the differentially expressed paralogous genes in response to changes in the availability of exogenous nutrients and provides insight into the evolutionary rationale underlying massive paralog retention in the Trichomonas genome
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