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Search Results: 1 - 10 of 296 matches for " Halina Norbertczak "
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Pseudogene accumulation in the evolutionary histories of Salmonella enterica serovars Paratyphi A and Typhi
Kathryn E Holt, Nicholas R Thomson, John Wain, Gemma C Langridge, Rumina Hasan, Zulfiqar A Bhutta, Michael A Quail, Halina Norbertczak, Danielle Walker, Mark Simmonds, Brian White, Nathalie Bason, Karen Mungall, Gordon Dougan, Julian Parkhill
BMC Genomics , 2009, DOI: 10.1186/1471-2164-10-36
Abstract: We report the 4.5 Mbp genome of a clinical isolate of Paratyphi A, strain AKU_12601, completely sequenced using capillary techniques and subsequently checked using Illumina/Solexa resequencing. Comparison with the published genome of Paratyphi A ATCC9150 revealed the two are collinear and highly similar, with 188 single nucleotide polymorphisms and 39 insertions/deletions. A comparative analysis of pseudogene complements of these and two finished Typhi genomes (CT18, Ty2) identified several pseudogenes that had been overlooked in prior genome annotations of one or both serovars, and identified 66 pseudogenes shared between serovars. By determining whether each shared and serovar-specific pseudogene had been recombined between Paratyphi A and Typhi, we found evidence that most pseudogenes have accumulated after the recombination between serovars. We also divided pseudogenes into relative-time groups: ancestral pseudogenes inherited from a common ancestor, pseudogenes recombined between serovars which likely arose between initial divergence and later recombination, serovar-specific pseudogenes arising after recombination but prior to the last evolutionary bottlenecks in each population, and more recent strain-specific pseudogenes.Recombination and pseudogene-formation have been important mechanisms of genetic convergence between Paratyphi A and Typhi, with most pseudogenes arising independently after extensive recombination between the serovars. The recombination events, along with divergence of and within each serovar, provide a relative time scale for pseudogene-forming mutations, affording rare insights into the progression of functional gene loss associated with host adaptation in Salmonella.Salmonella enterica serovars Typhi and Paratyphi A (Typhi, Paratyphi A) are human-restricted bacterial pathogens that cause related systemic diseases, known as typhoid, paratyphoid or enteric fever [1]. Together, these pathogens infect more than 25 million people annually worl
The genome sequence of the fish pathogen Aliivibrio salmonicida strain LFI1238 shows extensive evidence of gene decay
Erik Hjerde, Marit Lorentzen, Matthew TG Holden, Kathy Seeger, Steinar Paulsen, Nathalie Bason, Carol Churcher, David Harris, Halina Norbertczak, Michael A Quail, Suzanne Sanders, Scott Thurston, Julian Parkhill, Nils Willassen, Nicholas R Thomson
BMC Genomics , 2008, DOI: 10.1186/1471-2164-9-616
Abstract: In total, 4 286 protein coding sequences were identified, and the 4.6 Mb genome of A. salmonicida has a six partite architecture with two chromosomes and four plasmids. Sequence analysis revealed a highly fragmented genome structure caused by the insertion of an extensive number of insertion sequence (IS) elements. The IS elements can be related to important evolutionary events such as gene acquisition, gene loss and chromosomal rearrangements. New A. salmonicida functional capabilities that may have been aquired through horizontal DNA transfer include genes involved in iron-acquisition, and protein secretion and play potential roles in pathogenicity. On the other hand, the degeneration of 370 genes and consequent loss of specific functions suggest that A. salmonicida has a reduced metabolic and physiological capacity in comparison to related Vibrionaceae species.Most prominent is the loss of several genes involved in the utilisation of the polysaccharide chitin. In particular, the disruption of three extracellular chitinases responsible for enzymatic breakdown of chitin makes A. salmonicida unable to grow on the polymer form of chitin. These, and other losses could restrict the variety of carrier organisms A. salmonicida can attach to, and associate with. Gene acquisition and gene loss may be related to the emergence of A. salmonicida as a fish pathogen.Aliivibrio salmonicida (formerly Vibrio salmonicida) is a facultative pathogen of fish responsible for causing cold-water vibriosis (CV) in farmed Atlantic salmon (Salmo salar), sea farmed rainbow trout (Oncorhynchus mykiss) and captive Atlantic cod (Gadus morhua) [1]. At the peak of its prevalence in the 1980s infected fish farms suffered heavy losses reaching 50–90% [2]. CV appeared to be effectively controlled in 1998 [3] but before vaccination was introduced, A. salmonicida was estimated to have been responsible for over 80% of disease related losses to the Norwegian aquaculture industry [4]. Although the impact
Quantum Field Theory of Graphene with Dynamical Partial Symmetry Breaking  [PDF]
Halina V. Grushevskaya, George Krylov
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.510100
Abstract:

The quantum field theory approach has been proposed for the description of graphene electronic properties. It generalizes massless Dirac fermion model and is based on the Dirac-Hartree-Fock self-consistent field approximation and assumption on antiferromagnetic ordering of graphene lattice. The developed approach allows asymmetric charged carriers in single layer graphene with partially degenerated Dirac cones.

The genome of Rhizobium leguminosarum has recognizable core and accessory components
J Peter W Young, Lisa C Crossman, Andrew WB Johnston, Nicholas R Thomson, Zara F Ghazoui, Katherine H Hull, Margaret Wexler, Andrew RJ Curson, Jonathan D Todd, Philip S Poole, Tim H Mauchline, Alison K East, Michael A Quail, Carol Churcher, Claire Arrowsmith, Inna Cherevach, Tracey Chillingworth, Kay Clarke, Ann Cronin, Paul Davis, Audrey Fraser, Zahra Hance, Heidi Hauser, Kay Jagels, Sharon Moule, Karen Mungall, Halina Norbertczak, Ester Rabbinowitsch, Mandy Sanders, Mark Simmonds, Sally Whitehead, Julian Parkhill
Genome Biology , 2006, DOI: 10.1186/gb-2006-7-4-r34
Abstract: The 7.75 Mb genome comprises a circular chromosome and six circular plasmids, with 61% G+C overall. All three rRNA operons and 52 tRNA genes are on the chromosome; essential protein-encoding genes are largely chromosomal, but most functional classes occur on plasmids as well. Of the 7,263 protein-encoding genes, 2,056 had orthologs in each of three related genomes (Agrobacterium tumefaciens, Sinorhizobium meliloti, and Mesorhizobium loti), and these genes were over-represented in the chromosome and had above average G+C. Most supported the rRNA-based phylogeny, confirming A. tumefaciens to be the closest among these relatives, but 347 genes were incompatible with this phylogeny; these were scattered throughout the genome but were over-represented on the plasmids. An unexpectedly large number of genes were shared by all three rhizobia but were missing from A. tumefaciens.Overall, the genome can be considered to have two main components: a 'core', which is higher in G+C, is mostly chromosomal, is shared with related organisms, and has a consistent phylogeny; and an 'accessory' component, which is sporadic in distribution, lower in G+C, and located on the plasmids and chromosomal islands. The accessory genome has a different nucleotide composition from the core despite a long history of coexistence.The symbiosis between legumes and N2-fixing bacteria (rhizobia) is of huge agronomic benefit, allowing many crops to be grown without N fertilizer. It is a sophisticated example of coupled development between bacteria and higher plants, culminating in the organogenesis of root nodules [1]. There have been many genetic analyses of rhizobia, notably of Sinorhizobium meliloti (the symbiont of alfalfa), Bradyrhizobium japonicum (soybean), and Rhizobium leguminosarum, which has biovars that nodulate peas and broad beans (biovar viciae), clovers (biovar trifolii), or kidney beans (biovar phaseoli).The Rhizobiales, an α-proteobacterial order that also includes mammalian pathogens B
Normy spo ycia t uszczu dla dzieci zdrowych w wieku 2-3 lat
Halina Weker
Pediatria Wspó?czesna , 2001,
Abstract: Przedstawiono zalecenia dotycz ce spo ycia t uszczu w dzieciństwie. Badania na temat roli t uszczu w ywieniu oraz profilaktyki przeciwmia d ycowej nie potwierdzi y jednoznacznie skuteczno ci ograniczania spo ycia t uszczu ju u najm odszych dzieci w zapobieganiu rozwojowi mia d ycy.
Wspó dzia anie pomi dzy glutaminianem a kwasem γ-aminomas owym w o rodkowym uk adzie nerwowym
Halina Car
Neuropsychiatria i Neuropsychologia , 2009,
Abstract: Glutamate is the main excitatory neurotransmitter inthe brain and it is the precursor of the primary inhibitoryneurotransmitter, GABA. It is estimated that over 50%of neurons in the brain are glutamatergic and up to 40%of brain neurons may utilize GABA. A physiologicprocesses require a balance between glutamate-mediatedexcitatory and GABA-mediated inhibitory synaptictransmission. The proper cooperation between theseneurotransmitters represents a fundamental mechanismfor controlling nervous system function. Presynapticglutamatergic and GABAergic receptors controlglutamate and GABA release at many synapses inthe nervous system. The glutamate and GABA can bereleased by the same neuron and this may enhancethe spatial and temporal control of synaptic transmissionand participate in the maturation of synapses, in motoractivity and it is the homeostatic opposition tohyperexcitability, e.g. during seizures. The synapticplasticity which is basis for neurogenesis in adults andduring development as well as in learning and memoryprocesses is strongly dependent on activity these systems.The modulation of proteolytic activity of extracellularmatrix in the brain is probably under control excitatoryand inhibitory transmission. The disbalance betweenglutamate and GABA is observed in elderly and mayparticipate in the pathophysiology of neuropsychiatricdisorders including Huntington’s and Alzheimer’sdiseases, schizophrenia, stroke and many others. Theunderstanding mechanism of cooperation betweenglutamate and GABA is important for discovery newtherapies of CNS.
Inga Iwasiów, Ku s ońcu
Halina Scholtysik
Slavica Bruxellensia : Revue Polyphonique de Littérature, Culture et Histoire Slaves , 2010,
Abstract: Ku s ońcu (Vers le soleil), le dernier livre du professeur de l’Université de Szczecin Inga Iwasiów, est la continuation de son roman Bambino, qui avait été très bien re u par la critique et même nominé à d’importants prix littéraires. Même si cela permet d’entrer plus facilement dans les destins entremêlés de trois générations de héros, il n’est toutefois pas nécessaire de conna tre la première partie pour lire ce nouveau tome. Inga Iwasiów se concentre ici sur quelques personnages unis par ...
Tests of QCD at low $x$
Halina Abramowicz
Physics , 1996,
Abstract: This talk reviews the latest measurements of the proton, Pomeron and photon structure functions. These measurements, especially at low $x$ and/or low $Q^2$ lead to new insight into the picture of hadronic interactions.
The HERA challenges for LHC
Halina Abramowicz
Physics , 2009,
Abstract: Over the last two decades, the HERA collider has provided a large amount of new information about QCD dynamics at high energy. While the most appreciated are the measurements of the proton structure functions in a wide range of parton momentum x and virtuality Q^2, it is hard to believe that some of the observations at HERA which do not fit the simple picture of DGLAP dynamics would not get amplified at the LHC, possibly rendering certain approaches to searches beyond the Standard Model inadequate.
Production of large rapidity gap events in ep interactions at HERA
Halina Abramowicz
Physics , 1995,
Abstract: This is a short review of the properties of electron proton interactions characterized by the presence of large rapidity gaps (LRG) in the measured hadronic final state as obtained by the ZEUS Collaboration at the HERA Collider. In the deep inelastic neutral current $ep$ interactions, the factorization properties of the LRG events interpreted as due to the diffractive dissociation of the virtual photon are compatible with expectations from the Regge phenomenology of soft interactions. The measurement of deep inelastic scattering combined with results from photoproduction of high $p_T$ jets are successfully interpreted in terms of a factorizable Pomeron consisting of quarks and with a substantial contribution of a gluonic component. The first hints of a more complicated nature of the Pomeron are observed in the deep inelastic exclusive $\rho^o$ production, where a strong increase of the production cross section with energy is observed relative to the measurements of the NMC Collaboration at lower energy.
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