• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 169
  • 46
  • 37
  • 17
  • 14
  • 8
  • 5
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 358
  • 208
  • 57
  • 50
  • 49
  • 35
  • 34
  • 34
  • 33
  • 31
  • 27
  • 26
  • 25
  • 25
  • 22
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Influence of Salmonella specific bacteriophages (O1; S16) on the shedding of naturally occurring Salmonella and an orally applied Salmonella Eastbourne strain in bearded dragons (Pogona vitticeps)

Renfert, Kevin, Rabsch, Wolfgang, Fruth, Angelika, Marschang, Rachel Elizabeth, Speck, Stephanie, Pees, Michael 08 February 2022 (has links)
This study determined the passage time and phage propagation time of salmonella specific phages, Felix O1 and S16, in 10 bearded dragons, based on re‐isolation from cloacal swabs and faecal samples following oral administration, as a possible tool for reducing salmonella shedding. In Study 1, Felix O1 was administered orally for 12 consecutive days. Over 60 days, swabs were taken from the oral cavity and cloaca and qualitative Salmonella detection as well as salmonella quantification from faecal samples were performed. In Study 2, a phage cocktail (Felix O1 and S16) was administered to half of the tested animals. Salmonella (S.) Eastbourne was also given orally to all animals. Oral and cloacal swabs were tested as in Study 1, and faecal samples were collected for phage quantification. Various Salmonella serovars were detectable at the beginning of the study. The numbers of serovars detected declined over the course of the study. S. Kisarawe was most commonly detected. Salmonella titres ranged from 102 to 107 cfu/g faeces. The phages (Felix O1 and S16) were detectable for up to 20 days after the last administration. The initial phage titres ranged from 103 to 107 pfu/ml. The study shows that the phages were able to replicate in the intestine, and were shed for a prolonged period and therefore could contribute to a reduction of Salmonella shedding.
242

Characterization of the <i>Vibrio cholerae</i> Phage Shock Protein Response

DeAngelis, Cara Marie 28 August 2019 (has links)
No description available.
243

Isolierung und Charakterisierung eines phagenähnlichen Bacteriocins und eines virulenten Phagen und deren therapeutische Einsatzmöglichkeiten gegen Yersinia enterocolitica-Infektionen

Kaspar, Heike Maria 10 November 2003 (has links)
Durch die wachsende Anzahl von multiresistenten Bakterien, die auch durch den Mißbrauch von Antibiotika als Masthilfsmittel in der Tierzucht entstanden sind, erlangen alternative Methoden zur Bekämpfung bakterieller Infektionen ihre Bedeutung zurück. Diese Arbeit befaßt sich mit zwei Substanzen, um Infektionen mit Yersinia (Y.) enterocolitica einzudämmen. Es wurde in dieser Arbeit ein Bacteriocin aus Y. enterocolitica isoliert und charakterisiert. Das Reinigungschema folgte den Strategien der Phagenaufreinigung, angeschlossen wurde zur Überprüfung der Reinheit ein Gelfiltrationsschritt. Die Eigenschaften des gereinigten Enterocoliticins wurden in vitro und in vivo getestet. Im Zellkulturversuch zeigte sich das Enterocoliticin in der Abtötung von an eukaryonte Zellen adhärierten Bakterien als sehr wirksam, in eukaryonte Zellen eingewanderte Bakterien wurden hingegen nicht abgetötet. Aufgrund dieser vielversprechenden Ergebnisse wurde der Therapieansatz im Mausmodell angewendet. Das Mausmodell ist für Y. enterocolitica ein bereits erprobtes Modell. Die Tiere wurden oral infiziert, um den natürlichen Infektionsweg nachzustellen, das Enterocoliticin wurde ebenfalls oral verabreicht. Die Infektion wurde durch die Enterocoliticingabe nur unwesentlich beeinflußt, auch gelang der Nachweis des Enterocoliticins weder im Gastrointestinaltrakt noch in den Faeces. Die Therapie der infizierten Mäuse gelang auf diese Weise nicht. Weiterhin wurde ein Yersinia-Phage aus Schweinegülle isoliert, gereinigt und charakterisiert. Es handelt sich um einen T4-ähnlichen, virulenten Phagen mit einer Genomgröße von ca. 50 kbp und einem weiten Wirtsspektrum in Yersinia, das sogar speziesübergreifend ist. Da der Phage bei 37°C die Wirtszelle lysiert und durch seine hohe Wirksamkeit in vitro erschien der Phage von seinen Eigenschaften her zur Phagentherapie als geeignet. Es wurden analog zum Enterocoliticin-Tierexperiment Mäuse mit Y. enterocolitica oral infiziert, diesen Tieren wurde der Phage auf unterschiedlichen Wegen und zu unterschiedlichen Zeitpunkten appliziert. Die Tiere zeigten bei der parenteralen Gabe keinerlei Unverträglichkeitserscheinungen, bei der oralen Gabe wurde der Magensaft zuvor abgepuffert. Der Therapieerfolg im Vergleich zur Kontrollgruppe war wenig vielversprechend, es zeigten sich sehr ähnliche Infektionsverläufe in Kontroll-und Therapiegruppe. Diese beiden untersuchten Alternativwege zur Behandlung von Yersiniosen erwiesen sich bei den angewendeten Methoden bislang als nicht erfolgreich, dennoch muß auf diesem Gebiet weitergeforscht werden, wie erfolgreiche Therapieansätze aus anderen Tiermodellen zeigen. Es wirken nur wenige Phagen im Organismus als Therapeutikum, dennoch müssen diese Untersuchungen unternommen werden, um im Organismus wirksame, antibakterielle Substanzen zu finden und um einen Alternativweg zur Antibiotikumtherapie zu entwickeln. / The increasing number of multi-resistant bacteria, which resulted also from the abuse of antibiotics as mast additives in animal breeding, alternative methods regain importance for the combat at bacterial infections back. In this work two substances were investigated to restrict infections with Yersinia (Y.) enterocolitica. In this study a bacteriocin from Y. enterocolitica, designated enterocoliticin, was isolated and characterized. The purification strategy followed protocols of phage isolation. The purified preparations were examined by final gel filtration step. The properties of the purifed enterocoliticin were tested in vitro and in vivo. In a cell culture assay enterocoliticin was able to kill bacteria adherent to eukaryontic cells very effectively, however, bacteria invaded into eukaryotic cells were not affected. Due to these results enterocoliticin was applied in a mouse-infection-model in a therapeutic attempt. The mouse infection model is a well established system for infections with Y. enterocolitica. The animals were orally infected with Yersinia, and the enterocoliticin was orally applied, too. The infection was only insignificantly influenced by enterocoliticin. In addition of enterocoliticin was not detected succeeded in the gastro-intestinal-tract or in the faeces. The therapy of the infected mice did not succeed in this way. Furthermore, a Yersinia phage from pig manure was isolated and characterized. It is a T4 phage like virulent phage, containing a genom of approx. 50 kbp and posessing a wide host-range in Yersinia. Because of lytic properties of the phage at 37°C and his high effectiveness in vitro the phage appeared to be for phage therapy experiments. Similarly to the enterocoliticin experiment mice were infected with Y. enterocolitica orally, these animals were treated with the phage on different application routes and different time points. The animals did not show any incompatibilities upon parenteral gift. Before oral administration of the phage the gastric juice was buffered. Therapy outcome in comparison to the control group was little promising, it revealed a very similar infection process in control group and therapy group. These two investigated alternative ways for the control of Yersinia infections did not prove successful with the applied methods, however, further research must be carried out as successful therapeutical experiments from other animal models showed. It has to be considered that not all phages are appropriate as therapeutical agent however, more studies must be conducted to find more appropriate substances, which may work as effective antibacterial substances to develop alternative ways to antibiotic therapy.
244

Combination Antimicrobial Therapy: Synergistic Effect of a Cationic Zn-Containing Porphyrin with Lytic Bacteriophage PEV2 for Inhibition of Pseudomonas aeruginosa

Geyer, Jessica 07 August 2023 (has links)
No description available.
245

Investigation of the Roles of Pseudouridine Synthases in Ribosome Biogenesis and Epitranscriptomic Gene Regulation

Jayalath, Kumudie 03 December 2021 (has links)
No description available.
246

Temporal Proteomic and Lipidomic Analysis of Lytic and Lysogenic Mycobacteriophage

Lauren E Novak (11880353) 14 April 2022 (has links)
<p>  </p> <p>Phages are viruses that infect bacteria and use its host machinery to replicate. They are one of the most ubiquitous and diverse biological entities in the biosphere with a long evolutionary history. There is renewed interest in phage therapeutics due to increased levels of antimicrobial resistance (AMR) and decreased numbers of newly developed antibiotics. Additionally, phages have applications in food safety, water quality, biocontrol, and vaccines. While many phage genomes have been sequenced and annotated, proteomic and lipidomic profiles of phage have barely been explored. The aim of this research is to measure the protein and lipid dynamics of phages with different infection cycles at different timepoints in the host’s growth cycle using mass spectrometry (MS). The data produced from this experiment can verify genomic annotation, discover novel proteins and lipids, and inspire future mechanistic and functional studies. For this study, Krili and PotatoSplit, lytic cluster O and lysogenic cluster A3 mycobacteriophages, were used to infect <em>Mycobacterium smegmatis</em> during the mid-exponential growth stage. Samples were taken in triplicate at hours 0.5 (immediately after infection), 3 (early exponential), 7 (late exponential), and 10 (early stationary). The samples were washed, mechanically lysed, quantified on BCA assay, lipid extracted, protein digested and desalted. For MS analysis, the samples were analyzed using a HPLC-ESI-MS/MS. Protein data was processed using MaxQuant and lipid data using MS-DIAL and MS-FINDER. Normalized data was statistically analyzed on MetaboAnalyst, correlated on JMP, and functionally analyzed using DAVID. The results showed that the protein and lipid expression of both phages differed with time in comparison to the control (uninfected <em>Mycobacterium smegmatis</em>) and to each other. Additionally, phage protein-lipid correlations suggest simultaneous phage infection and bacterial defense mechanisms particularly during late infection. Temporal and correlation data produced from this experiment can be used for future targeted -omics research. As one of the first experiments of its kind, the MS workflow used in this study can provide a scaffold for future phage temporal proteomic and lipidomic analysis. </p>
247

Affibody phage display selections for lipid nanoparticle and affibody-mediated transient CAR T-cell therapy

Idris, Tasnim Yasin January 2022 (has links)
CAR T-cellbehandling är en immunterapi som har visat lovande resultat vid behandling av cancer. Trots det riktade immunsvaret som kan uppnås, betonar komplexiteten i tillverkningsprocessen och behandlingsproceduren det utrymme somm finns för förbättringar. Omprogrammerade T-celler har illustrerat en hög persistens hos patienter, som utsätter dem för risken för systemisk toxicitet. In-vivo transienta CAR T-celler som använder självförstärkande mRNA leverade genom affinitetsproteinbelagda LNP, föreslås som ett standardiserat alternativ som möjligör dosering av terapin vid behov.  Med hjälp av fagdisplay utfördes ett urval av affibody molekyler mot de tre immunonkologiska målproteinerna CD5, CD8 och CD19, i fyra cykler. Monoklonal fag-ELISA och DNA-sekvensering identifierade sju förmodade kandidater mot CD5, en förmodad kandidat mot CD8 och tre mot CD19. SPR analys visade specifik binding från CD5 kandidaterna, medan binding till målprotein inte kunde påvisas för CD8- och CD19 kandidaterna. De identifierade CD5-bindarna kan konjugeras till LNP för T-cell inriktad leverans av själv-amplififerande mRNA, med genetisk kod för en valfri CAR. / Chimeric antigen receptor (CAR) T-cell therapy is an immunotherapy which has shown promising results in treating patients suffering from oncological malignancies. Despite the targeted immune response that can be achieved, elaborate manufacturing and procedure processes emphasise room for improvement. Engineered T-cells have illustrated a high persistence in patients, exposing them to the risk of systemic toxicity. In-vivo transient CAR T-cells using self-amplifying mRNA by delivery through affinity protein coated lipid nanoparticles (LNP) is proposed as a standardised and reversible alternative, allowing for dosing when needed. Using phage display technology, selection of affibody molecules toward the three immune oncology proteins CD5, CD8 and CD19 was performed in four cycles. Monoclonal phage enzyme-linked immunosorbent assay (ELISA) and DNA sequencing identified seven putative candidates toward CD5, one putative candidate was isolated toward CD8, and three toward CD19. Surface plasmon resonance analysis (SPR) showed specific target binding of the CD5 candidate binders, while target binding could not be demonstrated for the CD8 and CD19 candidates. The identified CD5 binders could be conjugated to LNP for T-cell targeted delivery of self-amplifying mRNA encoding any CAR of interest.
248

Characterization of a Lambdoid Phage Gene Encoding a Host Cell Attachment Spike

Henry, Matthew S. 31 July 2008 (has links)
No description available.
249

Using Phage Display to Determine Mesenchymal Stem Cell Contribution to Collagen Synthesis

Kelly, Michael C. 29 August 2017 (has links)
No description available.
250

Stochastic Simulation of the Phage Lambda System and the Bioluminescence System Using the Next Reaction Method

Ananthanpillai, Balaji January 2009 (has links)
No description available.

Page generated in 0.0598 seconds