University of Rijeka

About: University of Rijeka is a education organization based out in Rijeka, Croatia. It is known for research contribution in the topics: Population & Tourism. The organization has 3471 authors who have published 7993 publications receiving 110386 citations. The organization is also known as: Rijeka University & Sveučilište u Rijeci.

Attitudes and concerns of undergraduate university health sciences students in Croatia regarding complete switch to e-learning during COVID-19 pandemic: a survey.

Abstract: Croatia has closed all educational institutions after 32 cases of SARS-CoV-2 infection were confirmed and switched to exclusive e-learning. Health sciences university students may have been particularly affected with this change due to a lack of practical education. It is not known how health sciences students and schools have adjusted to exclusive e-learning. This study aimed to explore attitudes and concerns of health sciences students in Croatia regarding the complete switch to e-learning during the COVID-19 pandemic. Eligible participants were students from 9 institutions offering university-level health sciences education in Croatia enrolled in the academic year 2019/2010, and participating in e-learning. Data were collected with a questionnaire distributed via email during April/May 2020. A total of 2520 students (aged 25.7 ± 7.7 years) responded to the questionnaire (70.3% response rate). General satisfaction with exclusive e-learning was rated with average grade of 3.7 out of 5. Compared with previous education, exclusive e-learning was rated with average grade of 3.2 out of 5. Compared to classroom learning, equal or higher motivation to attend exclusive e-learning was reported by 64.4% of participants. With a longer duration of exclusive e-learning, equal or higher motivation was reported by 65.5% of participants. Less than half of the students indicated they felt deprived or concerned due to the lack of practical lessons. Most participants indicated that in the future, they would prefer to combine classic classroom and e-learning (N = 1403; 55.7%). Most health sciences students were satisfied with the exclusive e-learning, as well as their personal and institutional adjustment to it. Students’ feedback can help institutions to improve the exclusive e-learning experience for students in the time of the pandemic.

HtrA Homologue of Legionella pneumophila: an Indispensable Element for Intracellular Infection of Mammalian but Not Protozoan Cells

Abstract: Legionella pneumophila is a gram-negative, facultative intracellular bacterium that is the causative agent of Legionnaires' disease, a potentially lethal pneumonia Ubiquitous in the aquatic environment as a parasite of protozoa, the bacteria are transmitted to humans upon inhalation of contaminated aerosols generated by mechanical devices, such as whirlpools, cooling towers, and showerheads (7) Within the lungs, L pneumophila replicates intracellularly within macrophages and possibly alveolar epithelial cells (16, 27) Intracellular replication occurs within a phagosome that is blocked from maturation along the “default” endosomal-lysosomal degradation pathway and is surrounded by a ribosome-studded multilayer membrane (1, 34) The ability of L pneumophila to modulate the biogenesis of its phagosome into this idiosyncratic niche is controlled by the Dot/Icm type IV-like secretion system (40, 48) Interestingly, the life cycle of L pneumophila within protozoa is highly similar to that within mammalian cells at the morphological and molecular levels (3, 7, 13, 26, 32, 41) In both host cell types, intracellular replication results in lysis of the host cell Killing of macrophages and alveolar epithelial cells occurs in two phases (21); first, through caspase-3-mediated induction of apoptosis during early stages of the infection (20, 22–24, 28), followed by pore formation-mediated egress of the host cell upon termination of replication (11) In contrast, killing of amoebae does not involve apoptosis, but pore-forming toxin-mediated cytolysis is essential for killing and exiting the protozoan cell (23, 32) During the course of the infection, intracellular pathogens respond to changes in their microenvironment by a dramatic phenotypic modulation (2, 8, 9, 31) This response is most likely dictated by the nature of the phagosomal microenvironment, which seems to be distinct between intracellular pathogens (8, 31) Although the mechanisms by which intracellular bacterial pathogens modulate the biogenesis of their vacuoles into idiosyncratic replicative niches are now better understood, the biochemical nature of the replicative niches inhabited by intracellular pathogens is not known Because the ability to replicate intracellularly within host cells is central to its pathogenesis, L pneumophila must be able to efficiently adapt to its intracellular microenvironment In response to its unique intracellular niche within mammalian macrophages, L pneumophila undergoes a profound phenotypic modulation, increasing expression of at least 30 proteins At least 13 of these proteins, including GroEL/Hsp60, GroES, and GspA, are also induced by various in vitro stress stimuli (1, 5, 6) This indicates that, although blocked from acidification and endosomal maturation, L pneumophila encounters a hostile microenvironment within the phagosome (8, 31) The role of the stress response by L pneumophila in its adaptation to the intracellular microenvironment within macrophages is not known Whether L pneumophila manifests a stress response within protozoa and the role of this response in intracellular replication are also not known In this study we show that the htrA/degP homologue of L pneumophila is indispensable for intracellular replication within mammalian cells in vitro and in vivo, yet is dispensable for the intracellular infection of protozoa Our data provide evidence that, despite the similarity in the intracellular infection of mammalian and protozoan cells by L pneumophila, significant differences exist in the phagosomal microenvironment of the two evolutionarily distant hosts

Cell biology and molecular ecology of Francisella tularensis

Abstract: Francisella tularensis is a highly infectious intracellular bacterium that causes the fulminating disease tularemia, which can be transmitted between mammals by arthropod vectors. Genomic studies have shown that the F. tularensis has been undergoing genomic decay with the most virulent strains having the lowest number of functional genes. Entry of F. tularensis into macrophages is mediated by looping phagocytosis and is associated with signalling through Syk tyrosine kinase. Within macrophages and arthropod-derived cells, the Francisella-containing phagosome matures transiently into an acidified late endosome-like phagosome with limited fusion to lysosomes followed by rapid bacterial escape into the cytosol within 30-60 min, and bacterial proliferation within the cytosol. The Francisella pathogenicity island, which potentially encodes a putative type VI secretion system, is essential for phagosome biogenesis and bacterial escape into the cytosol within macrophages and arthropod-derived cells. Initial sensing of F. tularensis in the cytosol triggers IRF-3-dependent IFN-beta secretion, type I IFNR-dependent signalling, activation of the inflammasome mediated by caspase-1, and a pro-inflammatory response, which is suppressed by triggering of SHIP. The past few years have witnessed a quantum leap in our understanding of various aspects of this organism and this review will discuss these remarkable advances.

The Human Cytomegalovirus UL51 Protein Is Essential for Viral Genome Cleavage-Packaging and Interacts with the Terminase Subunits pUL56 and pUL89

Abstract: Cleavage of human cytomegalovirus (HCMV) genomes as well as their packaging into capsids is an enzymatic process mediated by viral proteins and therefore a promising target for antiviral therapy. The HCMV proteins pUL56 and pUL89 form the terminase and play a central role in cleavage-packaging, but several additional viral proteins, including pUL51, had been suggested to contribute to this process, although they remain largely uncharacterized. To study the function of pUL51 in infected cells, we constructed HCMV mutants encoding epitope-tagged versions of pUL51 and used a conditionally replicating virus (HCMV-UL51-ddFKBP), in which pUL51 levels could be regulated by a synthetic ligand. In cells infected with HCMV-UL51-ddFKBP, viral DNA replication was not affected when pUL51 was knocked down. However, no unit-length genomes and no DNA-filled C capsids were found, indicating that cleavage of concatemeric HCMV DNA and genome packaging into capsids did not occur in the absence of pUL51. pUL51 was expressed mainly with late kinetics and was targeted to nuclear replication compartments, where it colocalized with pUL56 and pUL89. Upon pUL51 knockdown, pUL56 and pUL89 were no longer detectable in replication compartments, suggesting that pUL51 is needed for their correct subnuclear localization. Moreover, pUL51 was found in a complex with the terminase subunits pUL56 and pUL89. Our data provide evidence that pUL51 is crucial for HCMV genome cleavage-packaging and may represent a third component of the viral terminase complex. Interference with the interactions between the terminase subunits by antiviral drugs could be a strategy to disrupt the HCMV replication cycle.