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Prevalence of bacteriocins and their co-association with virulence factors within Pseudomonas aeruginosa catheter isolates
DUFKOVÁ, Kristýna
Urinary tract infections caused by Pseudomonas aeruginosa present a serious complication in the context of urinary catheter use. P. aeruginosa are equipped with various virulence determinants that may result in increased resistance. That contributes to higher morbidity and mortality in vulnerable patients. Pyocins are proteinaceous agents produced by pseudomonads with an antimicrobial effect targeting closely related bacteria. In this study, we examined the inhibition interactions among a set of 135 P. aeruginosa clinical isolates originated from the catheter-associated urinary tract infections. Togerther with pyocinogeny, the co-occurrence of other virulence factors and their co-association with pyocins were examined. The strong antagonistic interactions and high prevalence of pyocin genes among the isolates were observed. The overall competitive interactions provide promising findings in the area of alternative antibiotic approaches.
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Diversity and Ecological Role of Cyanobacterial Lipopeptides
GALICA, Tomáš
The presented study focuses on the biosynthesis and distribution of lipopeptides in the context of evolutionary history and life strategies of cyanobacteria. Cyanobacteria are ancient organisms often naturally exposed to situations in which other bacteria, such as Bacillus or Pseudomonas, were shown to employ lipopeptides to facilitate colony expansion or iron acquisition. The study explores these analogies and maps the distribution and diversity of lipopeptides across cyanobacteria with various lifestyles. Furthermore, the study provides evidence that widespread cyanobacterial lipopeptides containing a particular structural motif with two -hydroxy aspartate residues are a part of iron stress response and likely facilitate iron acquisition. The gathered information aims to integrate and deepen our knowledge of the ecophysiological roles of cyanobacterial lipopeptides.
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Secondary metabolites in fungal pathogenesis
Veselý, Martin ; Čmoková, Adéla (advisor) ; Machová, Lenka (referee)
The ability of fungal pathogens to induce infection and later survive in its host is dependent on virulence factors. Often these factors are based on primary metabolites (hydrophobins, proteases, phospholipases, catalases etc.). Nonetheless many pathogen produced secondary metabolites are also involved in the infection process. Their true role during infection used to be rather undervalued. First part of this bachelor degree thesis aims to describe host-pathogen relation and afterwards introduce reader with some basic, commonly accepted virulence factors of fungi. In the second part of this thesis known roles of secondary metabolites are described in each stages of progressing infection. In the first stage a pathogen needs to create a suitable habitat on host tissues to ensure growth. This is in part done by antimicrobial substances (...). In later stages pathogen prevents phagocytosis of its spores by host (melanins). Successful infection is often accompanied with host tissue damage that is induced by production of cytotoxic substances (xanthomegnin, riboflavin) and immunoregulation of host immune system (gliotoxin, pseurotin). Last but not least there are virulence factors that ensure prolonged survival in host (siderophores). Fungal pathogens of poikiloterm animals are mostly not primary...
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