1461 research outputs found
Sort by
Rola regulatorów transkrypcji w kontroli ekspresji genów prokariotycznych na przykładzie modelowej bakterii Pseudomonas aeruginosa
Get PDFBakterie Pseudomonas aeruginosa spotykane są często w środowisku naturalnym jak woda
czy gleba, ale zaliczane są także do oportunistycznych patogenów ludzi i zwierząt.
Charakteryzuje je duża zdolność do przetrwania w bardzo różnych niszach ekologicznych.
Adaptacja i umiejętność dostosowania do zmiennych warunków środowiska wynika z rozbudowanych
sieci regulacyjnych tych bakterii i wykorzystania bogatego repertuaru kodowanych
w genomie białek, ścieżek metabolicznych, mechanizmów obronnych i adaptacyjnych.
Regulatory transkrypcji są kluczowymi elementami regulacji ekspresji genów, które odpowiadają
na sygnały z otoczenia, włączając lub wyłączając określone ścieżki. Kompleksowe
badania regulatorów transkrypcji z wykorzystaniem metod transkryptomicznych, genomicznych,
regulacyjnych dostarczają wiedzy na temat mechanizmów ich działania, regulowanych
genów i procesów, umożliwiając poznanie i zrozumienie często skomplikowanych
sieci regulacyjnych zawiadujących przeżyciem komórki w danym środowisku i warunkach.
Celem niniejszej pracy jest przedstawienie kluczowych zagadnień związanych z regulacją
transkrypcji bakteryjnej na podstawie przeglądu danych literaturowych oraz zobrazowanych
na przykładzie P. aeruginosa i charakterystyki mechanizmów regulacji ekspresji genów
zaangażowanych między innymi w wirulencję tej bakterii
BVLOS UAV missions for vegetation mapping in maritime Antarctic
Get PDFPolar areas are among the regions where climate change occurs faster than on most of the other areas on Earth. To study the effects of climate change on vegetation, there is a need for knowledge on its current status and properties. Both classic field observation methods and remote sensing methods based on manned aircraft or satellite image analysis have limitations. These include high logistic operation costs, limited research areas, high safety risks, direct human impact, and insufficient resolution of satellite images. Fixed-wing unmanned aerial vehicle beyond the visual line of sight (UAV BVLOS) missions can bridge the scale gap between field-based observations and full-scale airborne or satellite surveys. In this study the two operations of the UAV BVLOS, at an altitude of 350m ASL, have been successfully performed in Antarctic conditions. Maps of the vegetation of the western shore of Admiralty Bay (King George Island, South Shetlands, Western Antarctic) that included the Antarctic Specially Protected Area No. 128 (ASPA 128) were designed. The vegetation in the 7.5 km2
area was mapped in ultra-high-resolution(<5cm and
DEM of 0.25m GSD), and from the Normalized Difference Vegetation Index (NDVI), four broad vegetation units were extracted: “dense moss carpets” (covering 0.14 km2
,0.8%ofASPA128), “Sanionia uncinata moss bed” (0.31 km2
, 1.7% of ASPA 128), “Deschampsia antarctica grass meadow” (0.24 km2,1.3% of ASPA 128), and “Deschampsia antarctica–Usnea antarctica heath” (1.66 km2,9.4% of ASPA 128). Our results demonstrate that the presented UAV BVLOS–based surveys are time-effective (single flight lasting 2.5 h on a distance of 300 km) and cost-effective when compared to classical field-based observations and are less invasive for the ecosystem. Moreover, unmanned airborne vehicles significantly improve security, which is of particular interest in polar region research. Therefore, their development is highly recommended for monitoring areas in remote and fragile environments.
KEYWORD
Divergent contribution of the MVA and MEP pathways to the formation of polyprenols and dolichols in Arabidopsis
Get PDFIsoprenoids, including dolichols (Dols) and polyprenols (Prens), are ubiquitous components of eukaryotic cells. In plant cells, there are two pathways that produce precursors
utilized for isoprenoid biosynthesis: the mevalonate (MVA) pathway and the methylerythritol phosphate (MEP) pathway. In this work, the contribution of these two pathways to the
biosynthesis of Prens and Dols was addressed using an in planta experimental model.
Treatment of plants with pathway-specific inhibitors and analysis of the effects of various light conditions indicated distinct biosynthetic origin of Prens and Dols. Feeding with deuteriated, pathway-specific precursors revealed that Dols, present in leaves and roots,
were derived from both MEP and MVA pathways and their relative contributions were modulated in response to precursor availability. In contrast, Prens, present in leaves, were almost exclusively synthesized via the MEP pathway. Furthermore, results obtained using a newly introduced here ‘competitive’ labeling method, designed so as to neutralize the imbalance of metabolic flow resulting from feeding with a single pathway-specific precursor,
suggest that under these experimental conditions one fraction of Prens and Dols is synthesized solely from endogenous precursors (deoxyxylulose or mevalonate), while the other fraction is synthesized concomitantly from endogenous and exogenous precursors.
Additionally, this report describes a novel methodology for quantitative separation of 2H and 13C distributions observed for isotopologues of metabolically labeled isoprenoids.
Collectively, these in planta results show that Dol biosynthesis, which uses both pathways, is significantly modulated depending on pathway productivity, while Prens are consistently derived from the MEP pathway
Candidatus Neoehrlichia mikurensis and Hepatozoon sp. in voles (Microtus spp.): occurrence and evidence for vertical transmission
Get PDFCandidatus Neoehrlichia mikurensis (CNM) and Hepatozoon spp. are important vector-borne parasites of humans and animals. CNM is a relatively recently discovered pathogen of humans. Hepatozoon are parasites of reptiles, amphibians and mammals, commonly found in rodents and carnivores worldwide. The present study aimed to determine the prevalence of CNM and Hepatozoon spp. in three species of Microtus and to assess the occurrence of vertical transmission in naturally-infected voles. Molecular techniques were used to detect pathogen DNA in blood and tissue samples of captured voles and their offspring. The prevalence of CNM in the vole community ranged 24–47% depending on Microtus species. The DNA of CNM was detected in 21% of pups from three litters of six infected Microtus dams (two Microtus arvalis and one M. oeconomus) and in 3/45 embryos (6.6%) from two litters of eight CNM-infected pregnant females. We detected Hepatozoon infection in 14% of M. arvalis and 9% of M. oeconomus voles. Hepatozoon sp. DNA was detected in 48.7% of pups from seven litters (6 M. arvalis and 1 M. oeconomus) and in two embryos (14.3%) obtained from one M. arvalis litter. The high prevalence of CNM infections in the Microtus spp. community may be a result of a relatively high rate of vertical transmission among naturally infected voles. Vertical transmission was also demonstrated for Hepatozoon sp. in M. arvalis and M. oeconomus. Our study underlines the significance of alternative routes of transmission of important vector-borne pathogens
Serum Metabolite Biomarkers for Pancreatic Tumors: Neuroendocrine and Pancreatic Ductal Adenocarcinomas—A Preliminary Study
Get PDFPreference of bacterial rhamnosyltransferases for 6‑deoxysugars reveals a strategy to deplete O‑antigens
Get PDFBacteria synthesize hundreds of bacteria-specific or “rare” sugars that are absent in mammalian cells and enriched in
6-deoxy monosaccharides such as L-rhamnose (L-Rha). Across bacteria, L-Rha is incorporated into glycans by rhamnosyltransferases (RTs) that couple nucleotide sugar substrates (donors) to target biomolecules (acceptors). Since L-Rha is required for the biosynthesis of bacterial glycans involved in survival or host infection, RTs represent potential antibiotic or antivirulence targets.
However, purified RTs and their unique bacterial sugar substrates have been difficult to obtain. Here, we use synthetic nucleotide rare sugar and glycolipid analogs to examine substrate recognition by three RTs that produce cell envelope components in diverse species, including a known pathogen. We find that bacterial RTs prefer pyrimidine nucleotide-linked 6-deoxysugars, not those containing a C6-hydroxyl, as donors. While glycolipid acceptors must contain a lipid, isoprenoid chain length, and stereochemistry
can vary. Based on these observations, we demonstrate that a 6-deoxysugar transition state analog inhibits an RT in vitro and reduces levels of RT-dependent O-antigen polysaccharides in Gram-negative cells. As O-antigens are virulence factors, bacteria-specific sugar transferase inhibition represents a novel strategy to prevent bacterial infections
Robust ParB Binding to Half-parS Sites in Pseudomonas aeruginosa—A Mechanism for Retaining ParB on the Nucleoid?
Get PDFChromosome segregation in Pseudomonas aeruginosa is assisted by the tripartite ParAB–parS system, composed of an ATPase (ParA), a DNA-binding protein (ParB) and its target parS sequence(s). ParB forms a nucleoprotein complex around four parSs (parS1–parS4) that overlaps oriC and facilitates relocation of newly synthesized ori domains inside the cells by ParA. Remarkably, ParB of P. aeruginosa also binds to numerous heptanucleotides (half-parSs) scattered in the genome. Here, using chromatin immunoprecipitation-sequencing (ChIP-seq), we analyzed patterns of ParB genome occupancy in cells growing under conditions of coupling or uncoupling between replication and cell division processes. Interestingly, a dissipation of ParB–parS complexes and a shift of ParB to half-parSs were observed during the transition from the exponential to stationary phase of growth on rich medium, suggesting the role of half-parSs in retaining ParB on the nucleoid within non-dividing P. aeruginosa cells. The ChIP-seq analysis of strains expressing ParB variants unable to dislocate from parSs showed that the ParB spreading ability is not required for ParB binding to half-parSs. Finally, a P. aeruginosa strain with mutated 25 half-parSs of the highest affinity towards ParB was constructed and analyzed. It showed altered ParB coverage of the oriC region and moderate changes in gene expression. Overall, this study characterizes a novel aspect of conserved bacterial chromosome segregation machinery
Design, construction, and functional characterization of a tRNA neochromosome in yeast
Get PDFHere, we report the design, construction, and characterization of a tRNA neochromosome, a designer chromosome that functions as an additional, de novo counterpart to the native complement of Saccharomyces cerevisiae. Intending to address one of the central design principles of the Sc2.0 project, the ∼190-kb tRNA neochromosome houses all 275 relocated nuclear tRNA genes. To maximize stability, the design incorporates orthogonal genetic elements from non-S. cerevisiae yeast species. Furthermore, the presence of 283 rox recombination sites enables an orthogonal tRNA SCRaMbLE system. Following construction in yeast, we obtained evidence of a potent selective force, manifesting as a spontaneous doubling in cell ploidy. Furthermore, tRNA sequencing, transcriptomics, proteomics, nucleosome mapping, replication profiling, FISH, and Hi-C were undertaken to investigate questions of tRNA neochromosome behavior and function. Its construction demonstrates the remarkable tractability of the yeast model and opens up opportunities to directly test hypotheses surrounding these essential non-coding RNAs
Sequencing the Genomes of the First Terrestrial Fungal Lineages: What Have We Learned?
Get PDFThe first genome sequenced of a eukaryotic organism was for Saccharomyces cerevisiae, as reported in 1996, but it was more than 10 years before any of the zygomycete fungi, which are the early-diverging terrestrial fungi currently placed in the phyla Mucoromycota and Zoopagomycota, were sequenced. The genome for Rhizopus delemar was completed in 2008; currently, more than 1000 zygomycete genomes have been sequenced. Genomic data from these early-diverging terrestrial fungi revealed deep phylogenetic separation of the two major clades—primarily plant—associated saprotrophic and mycorrhizal Mucoromycota versus the primarily mycoparasitic or animal-associated parasites and commensals in the Zoopagomycota. Genomic studies provide many valuable insights into how these fungi evolved in response to the challenges of living on land, including adaptations to sensing light and gravity, development of hyphal growth, and co-existence with the first terrestrial plants. Genome sequence data have facilitated studies of genome architecture, including a history of genome duplications and horizontal gene transfer events, distribution and organization of mating type loci, rDNA genes and transposable elements, methylation processes, and genes useful for various industrial applications. Pathogenicity genes and specialized secondary metabolites have also been detected in soil saprobes and pathogenic fungi. Novel endosymbiotic bacteria and viruses have been discovered during several zygomycete genome projects. Overall, genomic information has helped to resolve a plethora of research questions, from the placement of zygomycetes on the evolutionary tree of life and in natural ecosystems, to the applied biotechnological and medical questions
The first report on Hepatozoon canis in dogs and wolves in Poland: clinical and epidemiological features
Get PDFBackground
Canine hepatozoonosis caused by Hepatozoon canis is a common infection in dogs, with frequent case reports from the Mediterranean region and more recently from several Central European countries, such as Hungary and Germany. Despite the high prevalence of H. canis in red foxes, no infections have been reported to date in dogs in Poland. We describe here the first autochthonous cases of H. canis infection in dogs, including their clinical features, and report the prevalence of H. canis in grey wolves from different regions of Poland.
Methods
Thin smears prepared from blood samples collected from dogs were evaluated by microscopic examination. A total of 60 wolves and 47 dogs were tested. Infections were confirmed by PCR and sequencing.
Results
Gamonts of H. canis were found in > 50% of the neutrophils of two dogs and in < 10% of the neutrophils in another five dogs. Molecular typing by PCR sequencing of the 18S ribosomal RNA gene fragment confirmed infections in 11 dogs from different regions of Poland, in 2.7% of dogs attending veterinary practices in central Poland and in 35% of wolves from various geographical regions of Poland. Clinical features manifested mostly in older dogs, and the most common signs were anaemia and apathy. Young dogs usually remained asymptomatic.
Conclusions
This is the first report of H. canis infection in dogs and wolves in Poland. Although the exact vector of the parasite is not known, veterinary practitioners should be aware of this new parasitosis and should consider appropriate diagnostics to confirm/exclude this infection. Further studies are needed to understand the transmission routes of H. canis in domestic and wild canids in Poland