Browsing by Subject "receptor"

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  • van Belkum, Alex; Almeida, Carina; Bardiaux, Benjamin; Barrass, Sarah V.; Butcher, Sarah J.; Caykara, Tugce; Chowdhury, Sounak; Datar, Rucha; Eastwood, Ian; Goldman, Adrian; Goyal, Manisha; Happonen, Lotta; Izadi-Pruneyre, Nadia; Jacobsen, Theis; Johnson, Pirjo H.; Kempf, Volkhard A. J.; Kiessling, Andreas; Bueno, Juan Leva; Malik, Anchal; Malmstrom, Johan; Meuskens, Ina; Milner, Paul A.; Nilges, Michael; Pamme, Nicole; Peyman, Sally A.; Rodrigues, Ligia R.; Rodriguez-Mateos, Pablo; Sande, Maria G.; Silva, Carla Joana; Stasiak, Aleksandra Cecylia; Stehle, Thilo; Thibau, Arno; Vaca, Diana J.; Linke, Dirk (2021)
    Infectious diseases are an existential health threat, potentiated by emerging and re-emerging viruses and increasing bacterial antibiotic resistance. Targeted treatment of infectious diseases requires precision diagnostics, especially in cases where broad-range therapeutics such as antibiotics fail. There is thus an increasing need for new approaches to develop sensitive and specific in vitro diagnostic (IVD) tests. Basic science and translational research are needed to identify key microbial molecules as diagnostic targets, to identify relevant host counterparts, and to use this knowledge in developing or improving IVD. In this regard, an overlooked feature is the capacity of pathogens to adhere specifically to host cells and tissues. The molecular entities relevant for pathogen-surface interaction are the so-called adhesins. Adhesins vary from protein compounds to (poly-)saccharides or lipid structures that interact with eukaryotic host cell matrix molecules and receptors. Such interactions co-define the specificity and sensitivity of a diagnostic test. Currently, adhesin-receptor binding is typically used in the pre-analytical phase of IVD tests, focusing on pathogen enrichment. Further exploration of adhesin-ligand interaction, supported by present high-throughput "omics" technologies, might stimulate a new generation of broadly applicable pathogen detection and characterization tools. This review describes recent results of novel structure-defining technologies allowing for detailed molecular analysis of adhesins, their receptors and complexes. Since the host ligands evolve slowly, the corresponding adhesin interaction is under selective pressure to maintain a constant receptor binding domain. IVD should exploit such conserved binding sites and, in particular, use the human ligand to enrich the pathogen. We provide an inventory of methods based on adhesion factors and pathogen attachment mechanisms, which can also be of relevance to currently emerging pathogens, including SARS-CoV-2, the causative agent of COVID-19.
  • Karjalainen, Eveliina (Helsingin yliopisto, 2019)
    Yeasts are significant plant pathogens, yet plant-yeast interactions are poorly understood. Mammals have immune receptors for yeast-specific MAMPs (microbe-associated molecular patterns), suggesting that plants might have similar receptors as well. Detection of MAMPs by PRRs (pattern recognition receptors) triggers the plant immune system, leading to the first phase of PTI (pattern-triggered immunity). The yeast cell wall is layered, so only some of the potential MAMP molecules, like mannans, are easily available for the plant receptors. In order to utilize yeasts and PRR-based yeast resistance in agriculture and forestry, it is crucial to identify these receptors and gain a better understanding of their functions in plant-yeast interactions. PRRs can be divided into two groups, RLPs (receptor-like proteins) and RLKs (receptor-like kinases). Some of the L-type lectin receptor kinases have already been shown to participate in the interactions between plants and fungi or fungal like pathogens, making them promising candidates for yeast receptors. G-type lectins remain less studied but have promising genes as well. In this thesis, we use forward and reverse genetics methods to show that lectin receptor kinases might include putative yeast pattern recognition receptors. We also establish the first protocol and genetic screen for the identification of plant PRRs participating in the recognition of yeast cell wall MAMPs. Only genes present in both silver birch (Betula pendula) and arabidopsis (Arabidopsis thaliana) were examined to enable following studies with an Arabidopsis model system of the interactions between silver birch and the dimorphic birch pathogen Taphrina betulina. This information can later be used in plant production with other plants and their yeasts as well.
  • Salem, Mabruka; Pajunen, Maria; Jun, Jin Woo; Skurnik, Mikael (2021)
    The Yersinia bacteriophages fPS-2, fPS-65, and fPS-90, isolated from pig stools, have long contractile tails and elongated heads, and they belong to genus Tequatroviruses in the order Caudovirales. The phages exhibited relatively wide host ranges among Yersinia pseudotuberculosis and related species. One-step growth curve experiments revealed that the phages have latent periods of 50-80 min with burst sizes of 44-65 virions per infected cell. The phage genomes consist of circularly permuted dsDNA of 169,060, 167,058, and 167,132 bp in size, respectively, with a G + C content 35.3%. The number of predicted genes range from 267 to 271. The phage genomes are 84-92% identical to each other and ca 85% identical to phage T4. The phage receptors were identified by whole genome sequencing of spontaneous phage-resistant mutants. The phage-resistant strains had mutations in the ompF, galU, hldD, or hldE genes. OmpF is a porin, and the other genes encode lipopolysaccharide (LPS) biosynthetic enzymes. The ompF, galU, and hldE mutants were successfully complemented in trans with respective wild-type genes. The host recognition was assigned to long tail fiber tip protein Gp38, analogous to that of T-even phages such as Salmonella phage S16, specifically to the distal beta-helices connecting loops.