1. Candidate pathogenicity factor/effector proteins of ‘Candidatus Phytoplasma solani’ modulate plant carbohydrate metabolism, accelerate the ascorbate–glutathione cycle, and induce autophagosomesMarina Dermastia, Špela Tomaž, Rebeka Strah, Tjaša Lukan, Anna Coll Rius, Barbara Dušak, Timotej Čepin, Aleš Kladnik, Maja Zagorščak, Kristina Gruden, Maruša Pompe Novak, 2023, izvirni znanstveni članek Povzetek: The pathogenicity of intracellular plant pathogenic bacteria is associated with the action of pathogenicity factors/effectors, but their physiological roles for most phytoplasma species, including ‘Candidiatus Phytoplasma solani’ are unknown. Six putative pathogenicity factors/effectors from six different strains of ‘Ca. P. solani’ were selected by bioinformatic analysis. The way in which they manipulate the host cellular machinery was elucidated by analyzing Nicotiana benthamiana leaves after Agrobacterium-mediated transient transformation with the pathogenicity factor/effector constructs using confocal microscopy, pull-down, and co-immunoprecipitation, and enzyme assays. Candidate pathogenicity factors/effectors were shown to modulate plant carbohydrate metabolism and the ascorbate–glutathione cycle and to induce autophagosomes. PoStoSP06, PoStoSP13, and PoStoSP28 were localized in the nucleus and cytosol. The most active effector in the processes studied was PoStoSP06. PoStoSP18 was associated with an increase in phosphoglucomutase activity, whereas PoStoSP28, previously annotated as an antigenic membrane protein StAMP, specifically interacted with phosphoglucomutase. PoStoSP04 induced only the ascorbate–glutathione cycle along with other pathogenicity factors/effectors. Candidate pathogenicity factors/effectors were involved in reprogramming host carbohydrate metabolism in favor of phytoplasma own growth and infection. They were specifically associated with three distinct metabolic pathways leading to fructose-6-phosphate as an input substrate for glycolysis. The possible significance of autophagosome induction by PoStoSP28 is discussed.
Ključne besede: autophagosome, effector, glycolysis, pathogenicity factor, StAMP
Objavljeno v DiRROS: 24.08.2023; Ogledov: 69; Prenosov: 23
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2. Jellyfish detritus supports niche partitioning and metabolic interactions among pelagic marine bacteriaTinkara Tinta, Zihao Zhao, Barbara Bayer, Gerhard J. Herndl, 2023, izvirni znanstveni članek Povzetek: Background: Jellyfsh blooms represent a signifcant but largely overlooked source of labile organic matter (jelly-OM) in the ocean, characterized by a high protein content. Decaying jellyfsh are important carriers for carbon export to the ocean’s interior. To accurately incorporate them into biogeochemical models, the interactions between microbes and jelly-OM have yet to be fully characterized. We conducted jelly-OM enrichment experiments in microcosms to simulate the scenario experienced by the coastal pelagic microbiome after the decay of a jellyfsh bloom. We combined metagenomics, endo- and exo-metaproteomic approaches to obtain a mechanistic understanding on the metabolic network operated by the jelly-OM degrading bacterial consortium. Results: Our analysis revealed that OM released during the decay of jellyfsh blooms triggers a rapid shufing of the taxonomic and functional profle of the pelagic bacterial community, resulting in a signifcant enrichment of protein/amino acid catabolism-related enzymes in the jelly-OM degrading community dominated by Pseudoalteromonadaceae, Alteromonadaceae and Vibrionaceae, compared to unamended control treatments. In accordance with the proteinaceous character of jelly-OM, Pseudoalteromonadaceae synthesized and excreted enzymes associated with proteolysis, while Alteromonadaceae contributed to extracellular hydrolysis of complex carbohydrates and organophosphorus compounds. In contrast, Vibrionaceae synthesized transporter proteins for peptides, amino acids and carbohydrates, exhibiting a cheater-type lifestyle, i.e. benefting from public goods released by others. In the late stage of jelly-OM degradation, Rhodobacteraceae and Alteromonadaceae became dominant, growing on jelly-OM left-overs or bacterial debris, potentially contributing to the accumulation of dissolved organic nitrogen compounds and inorganic nutrients, following the decay of jellyfsh blooms. Conclusions: Our fndings indicate that specifc chemical and metabolic fngerprints associated with decaying jellyfsh blooms are substantially diferent to those previously associated with decaying phytoplankton blooms, potentially altering the functioning and biogeochemistry of marine systems. We show that decaying jellyfsh blooms are associated with the enrichment in extracellular collagenolytic bacterial proteases, which could act as virulence factors in human and marine organisms’ disease, with possible implications for marine ecosystem services. Our study also provides novel insights into niche partitioning and metabolic interactions among key jelly-OM degraders
Ključne besede: jellyfish detritus, microbial consortia, metagenomics, metaproteomics, exoproteomics
Objavljeno v DiRROS: 09.08.2023; Ogledov: 91; Prenosov: 37
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4. Geographical and temporal diversity of ‘Candidatus Phytoplasma solani' in wine-growing regions in Slovenia and AustriaNataša Mehle, Sanda Kavčič, Sara Mermal, Sara Vidmar, Maruša Pompe Novak, Monika Riedle-Bauer, Günter Brader, Aleš Kladnik, Marina Dermastia, 2022, izvirni znanstveni članek Povzetek: As the causal agent of the grapevine yellows disease Bois noir, ‘Candidatus Phytoplasma solani’ has a major economic impact on grapevines. To improve the control of Bois noir, it is critical to understand the very complex epidemiological cycles that involve the multiple “Ca. P. solani” host plants and insect vectors, of which Hyalesthes obsoletus is the most important. In the present study, multiple genotyping of the tuf, secY, stamp, and vmp1 genes was performed. This involved archived grapevine samples that were collected during an official survey of grapevine yellows throughout the wine-growing regions of Slovenia (from 2003 to 2016), plus samples from Austrian grapevines, stinging nettle, field bindweed, and insect samples (collected from 2012 to 2019). The data show that the tuf-b2 type of the tuf gene has been present in eastern Slovenia since at least 2003. The hypotheses that the occurrence of the haplotypes varies due to the geographical position of Slovenia on the Italian–Slovenian Karst divide and that the haplotypes are similar between Slovenian and Austrian Styria were confirmed. The data also show haplotype changes for host plants and H. obsoletus associated with ‘Ca. P. solani,’ which might be linked to new epidemiological cycles of this phytoplasma that involve not just new plant sources and new insect vectors, but also climate and land-use changes.
Ključne besede: Bois noir, genotyping, ‘Ca. P. solani’, tuf gene, secY, survey, tuf-b2, stamp
Objavljeno v DiRROS: 10.06.2022; Ogledov: 538; Prenosov: 319
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9. Proteases and cytokines as mediators of interactions between cancer and stromal cells in tumoursBarbara Breznik, Helena Motaln, Tamara Lah Turnšek, pregledni znanstveni članek Povzetek: Proteolytic enzymes are highly relevant in different processes of cancer progression. Their interplay with other signalling molecules such as cytokines represents important regulation of multicellular cross-talk. In this review, we discuss protease regulation mechanisms of cytokine signalling in various types of cancer. Additionally, we highlight the reverse whereby cytokines have an impact on protease expression in an autocrine and paracrine manner, representing complex feedback mechanisms among multiple members of these two protein families. The relevance of the protease-cytokine axis is illustrated in glioblastoma, where interactions between normal mesenchymal stem cells and cancer cells play an important role in this very malignant form of brain cancer.
Ključne besede: cellular cross-talk, glioblastoma, invasion, mesenchymal stem cells, protease-cytokine signalling
Objavljeno v DiRROS: 08.09.2017; Ogledov: 3619; Prenosov: 1249
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