1. Insights into diversity, host-range, and temporal stability of Bacteroides and Phocaeicola prophagesNejc Stopnišek, Stina Hedžet, Tomaž Accetto, Maja Rupnik, 2025, izvirni znanstveni članek Povzetek: Background Phages are critical components of the gut microbiome, influencing bacterial composition and function as predators, parasites, and modulators of bacterial phenotypes. Prophages, integrated forms of these phages, are prevalent in many bacterial genomes and play a role in bacterial adaptation and evolution. However, the diversity and stability of prophages within gut commensals, particularly in the genera Bacteroides and Phocaeicola, remain underexplored. This study aims to screen and characterize prophages in these genera, providing insights into their diversity, host range, and temporal dynamics in the human gut. Results Using a combination of three bioinformatic tools—Cenote-Taker 3, Vibrant, and PHASTER—we conducted a comprehensive analysis of prophages in Bacteroides and Phocaeicola. Cenote-Taker 3 identified the most diverse set of prophages, with significant overlaps observed between the tools. After clustering high-quality prophages, we identified 22 unique viral operational taxonomic units (vOTUs). Notably, comparisons between prophages identified in isolated bacterial genomes, metaviromes, and large public gut virome databases revealed a broader host range than initially observed in single isolates. Certain prophages were consistent across time points and individuals, suggesting temporal stability. All identified prophages belonged to the Caudoviricetes class and contained genes related to antibiotic resistance, toxin production, and metabolic processes. Conclusions The combined use of multiple prophage detection tools allowed for a more comprehensive assessment of prophage diversity in Bacteroides and Phocaeicola. The identified prophages were not only prevalent but also exhibited broad host ranges and temporal stability. The presence of antibiotic resistance and toxin genes suggests that these prophages may significantly influence bacterial community structure and function in the gut, with potential implications for human health. These findings highlight the importance of using diverse detection tools to accurately assess prophage diversity and dynamics.
Ključne besede: prophage detection, Bacteroides, Phocaeicola, gut microbiome, prophage diversity, Caudoviricetes, antibiotic resistance, phage-bacteria interactions, temporal stability
Objavljeno v DiRROS: 06.03.2025; Ogledov: 180; Prenosov: 164
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2. New treatment approaches for Clostridioides difficile infections : alternatives to antibiotics and fecal microbiota transplantationTomaž Bratkovič, Abida Zahirović, Maruša Bizjak, Maja Rupnik, Borut Štrukelj, Aleš Berlec, 2024, pregledni znanstveni članek Povzetek: Clostridioides difficile causes a range of debilitating intestinal symptoms that may be fatal. It is particularly problematic as a hospital-acquired infection, causing significant costs to the health care system. Antibiotics, such as vancomycin and fidaxomicin, are still the drugs of choice for C. difficile infections, but their effectiveness is limited, and microbial interventions are emerging as a new treatment option. This paper focuses on alternative treatment approaches, which are currently in various stages of development and can be divided into four therapeutic strategies. Direct killing of C. difficile (i) includes beside established antibiotics, less studied bacteriophages, and their derivatives, such as endolysins and tailocins. Restoration of microbiota composition and function (ii) is achieved with fecal microbiota transplantation, which has recently been approved, with standardized defined microbial mixtures, and with probiotics, which have been administered with moderate success. Prevention of deleterious effects of antibiotics on microbiota is achieved with agents for the neutralization of antibiotics that act in the gut and are nearing regulatory approval. Neutralization of C. difficile toxins (iii) which are crucial virulence factors is achieved with antibodies/antibody fragments or alternative binding proteins. Of these, the monoclonal antibody bezlotoxumab is already in clinical use. Immunomodulation (iv) can help eliminate or prevent C. difficile infection by interfering with cytokine signaling. Small-molecule agents without bacteriolytic activity are usually selected by drug repurposing and can act via a variety of mechanisms. The multiple treatment options described in this article provide optimism for the future treatment of C. difficile infection.
Ključne besede: microbiota, immunomodulators
Objavljeno v DiRROS: 17.01.2025; Ogledov: 283; Prenosov: 139
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3. The physiological impact of GFLV virus infection on grapevine water status : first observationsAnastazija Jež Krebelj, Maja Cigoj, Marija Stele, Marko Chersicola, Maruša Pompe Novak, Paolo Sivilotti, 2022, izvirni znanstveni članek Povzetek: In a vineyard, grapevines are simultaneously exposed to combinations of several abiotic (drought, extreme temperatures, salinity) and biotic stresses (phytoplasmas, viruses, bacteria). With climate change, the incidences of drought in vine growing regions are increased and the host range of pathogens with increased chances of virulent strain development has expanded. Therefore, we studied the impact of the combination of abiotic (drought) and biotic (Grapevine fanleaf virus (GFLV) infection) stress on physiological and molecular responses on the grapevine of cv. Schioppettino by studying the influence of drought and GFLV infection on plant water status of grapevines, on grapevine xylem vessel occlusion, and on expression patterns of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1), 9-cis-epoxycarotenoid dioxygenase 2 (NCED2), WRKY encoding transcription factor (WRKY54) and RD22-like protein (RD22) genes in grapevines. A complex response of grapevine to the combination of drought and GFLV infection was shown, including priming in the case of grapevine water status, net effect in the case of area of occluded vessels in xylem, and different types of interaction of both stresses in the case of expression of four abscisic acid-related genes. Our results showed that mild (but not severe) water stress can be better sustained by GFLV infection rather than by healthy vines. GFLV proved to improve the resilience of the plants to water stress, which is an important outcome to cope with the challenges of global warming.
Ključne besede: grapevine, water status, virus infection, GFLV, xylem vessel occlusion, gene expression
Objavljeno v DiRROS: 16.07.2024; Ogledov: 534; Prenosov: 402
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4. The physiological impact of GFLV virus infection on grapevine water status : first observationsAnastazija Jež Krebelj, Maja Cigoj, Marija Stele, Marko Chersicola, Maruša Pompe Novak, Paolo Sivilotti, izvirni znanstveni članek Ključne besede: grapevine, water status, virus infection, GFLV, xylem vessel occlusion, gene expression
Objavljeno v DiRROS: 06.09.2022; Ogledov: 1272; Prenosov: 470
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