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1.
The VPS4 component of the ESCRT machinery plays an essential role in HPV infectious entry and capsid disassembly
Lawrence Banks, Colin Crump, Anna Gozdzicka-Jozefiak, Martina Bergant, David Pim, Paola Massimi, Justyna Broniarczyk, 2017, original scientific article

Abstract: Human Papillomavirus (HPV) infection involves multiple steps, from cell attachment, through endocytic trafficking towards the trans-Golgi network, and, ultimately, the entry into the nucleus during mitosis. An essential viral protein in infectious entry is the minor capsid protein L2, which engages different components of the endocytic sorting machinery during this process. The ESCRT machinery is one such component that seems to play an important role in the early stages of infection. Here we have analysed the role of specific ESCRT components in HPV infection, and we find an essential role for VPS4. Loss of VPS4 blocks infection with multiple PV types, suggesting an evolutionarily conserved critical step in infectious entry. Intriguingly, both L1 and L2 can interact with VPS4, and appear to be in complex with VPS4 during the early stages of virus infection. By using cell lines stably expressing a dominant-negative mutant form of VPS4, we also show that loss of VPS4 ATPase activity results in a marked delay in capsid uncoating, resulting in a defect in the endocytic transport of incoming PsVs. These results demonstrate that the ESCRT machinery, and in particular VPS4, plays a critical role in the early stages of PV infection.
Found in: ključnih besedah
Summary of found: ...Human Papillomavirus (HPV) infection involves multiple steps, from cell attachment, through...
Keywords: HPV, ESCRT machinery, infection
Published: 08.05.2017; Views: 1199; Downloads: 88
.pdf Fulltext (1,10 MB)

2.
Phosphorylation of HPV-16 L2 Contributes To Efficient Virus Infectious Entry
Robert L. Garcea, Michael P. Myers, Martina Bergant Marušič, David Pim, Paola Massimi, Justyna Broniarczyk, Lawrence Banks, 2019, original scientific article

Abstract: The Human Papillomavirus (HPV) capsid comprises two viral proteins, L1 and L2, with the L2 component being essential to ensure efficient endocytic transport of incoming viral genomes. Several studies have previously reported that L1 and L2 are post-translationally modified, but it is uncertain whether these modifications affect HPV infectious entry. Using a proteomic screen, we identified a highly conserved phospho-acceptor site on the HPV-16 and BPV-1 L2 proteins. The phospho-modification of L2, and its presence in HPV pseudovirions (PsVs), was confirmed using anti-phospho L2-specific antibodies. Mutation of the phospho-acceptor sites of both HPV-16 and BPV-1 L2 resulted in the production of infectious virus particles, with no differences in efficiency of packaging the reporter DNA. However, these mutated PsVs showed marked defects in infectious entry. Further analysis revealed a defect in uncoating, characterized by a delay in the exposure of a conformational epitope on L1 that indicates capsid uncoating. This uncoating defect was accompanied by a delay in the proteolysis of both L1 and L2 in mutated HPV-16 PsVs. Taken together, these studies indicate that phosphorylation of L2 during virus assembly plays an important role in optimal uncoating of virions during infection, suggesting that phosphorylation of the viral capsid proteins contributes to infectious entry.
Found in: ključnih besedah
Summary of found: ...role in optimal uncoating of virions during infection, suggesting that phosphorylation of the viral capsid...
Keywords: HPV, L2, infection, protein phosphorylation
Published: 05.06.2019; Views: 366; Downloads: 0
.pdf Fulltext (1,70 MB)

3.
Headspace volatile organic compounds from bacteria implicated in ventilator-associated pneumonia analysed by TD-GC/MS
Stephen J Fowler, Roy Goodacre, Iain R White, Tamara M E Nijsen, Waqar M Ahmed, Howbeer Muhamadali, Oluwasola Lawal, 2018, original scientific article

Abstract: Ventilator-associated pneumonia (VAP) is a healthcare-acquired infection arising from the invasion of the lower respiratory tract by opportunistic pathogens in ventilated patients. The current method of diagnosis requires the culture of an airway sample such as bronchoalveolar lavage, which is invasive to obtain and may take up to seven days to identify a causal pathogen, or indeed rule out infection. While awaiting results, patients are administered empirical antibiotics; risks of this approach include lack of effect on the causal pathogen, contribution to the development of antibiotic resistance and downstream effects such as increased length of intensive care stay, cost, morbidity and mortality. Specific biomarkers which could identify causal pathogens in a timely manner are needed as they would allow judicious use of the most appropriate antimicrobial therapy. Volatile organic compound (VOC) analysis in exhaled breath is proposed as an alternative due to its non-invasive nature and its potential to provide rapid diagnosis at the patient's bedside. VOCs in exhaled breath originate from exogenous, endogenous, as well as microbial sources. To identify potential markers, VAP-associated pathogens Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus were cultured in both artificial sputum medium and nutrient broth, and their headspaces were sampled and analysed for VOCs. Previously reported volatile markers were identified in this study, including indole and 1-undecene, alongside compounds that are novel to this investigation, cyclopentanone and 1-hexanol. We further investigated media components (substrates) to identify those that are essential for indole and cyclopentanone production, with potential implications for understanding microbial metabolism in the lung.
Found in: ključnih besedah
Summary of found: ...Ventilator-associated pneumonia (VAP) is a healthcare-acquired infection arising from the invasion of the lower...
Keywords: bacteria, exhaled breath, infection, ventilator-associated pneumonia, volatile organic compounds
Published: 18.07.2019; Views: 159; Downloads: 0

4.
TD/GC–MS analysis of volatile markers emitted from mono- and co-cultures of Enterobacter cloacae and Pseudomonas aeruginosa in artificial sputum
Craig Portsmouth, Pedro Povoa, Jan H Leopold, Pouline M P van Oort, Emili Diaz, Gemma Goma, Timothy Felton, Paul Dark, Alan Davie, Luis Coelho, Lieuwe D Bos, Marta Camprubi, Antonio Artigas, Jonathan Barnard-Smith, Waqar M Ahmed, Stephen J Fowler, Tamara M E Nijsen, Royston Goodacre, Weda Hans, Hugo knobel, Oluwasola Lawal, Iain R White, 2018, original scientific article

Abstract: Introduction: Infections such as ventilator-associated pneumonia (VAP) can be caused by one or more pathogens. Current methods for identifying these pathogenic microbes often require invasive sampling, and can be time consuming, due to the requirement for prolonged cultural enrichment along with selective and differential plating steps. This results in delays in diagnosis which in such critically ill patients can have potentially life-threatening consequences. Therefore, a non-invasive and timely diagnostic method is required. Detection of microbial volatile organic compounds (VOCs) in exhaled breath is proposed as an alternative method for identifying these pathogens and may distinguish between mono- and poly-microbial infections. Objectives: To investigate volatile metabolites that discriminate between bacterial mono- and co-cultures. Methods: VAP-associated pathogens Enterobacter cloacae and Pseudomonas aeruginosa were cultured individually and together in artificial sputum medium for 24 h and their headspace was analysed for potential discriminatory VOCs by thermal desorption gas chromatography–mass spectrometry. Results: Of the 70 VOCs putatively identified, 23 were found to significantly increase during bacterial culture (i.e. likely to be released during metabolism) and 13 decreased (i.e. likely consumed during metabolism). The other VOCs showed no transformation (similar concentrations observed as in the medium). Bacteria-specific VOCs including 2-methyl-1-propanol, 2-phenylethanol, and 3-methyl-1-butanol were observed in the headspace of axenic cultures of E. cloacae, and methyl 2-ethylhexanoate in the headspace of P. aeruginosa cultures which is novel to this investigation. Previously reported VOCs 1-undecene and pyrrole were also detected. The metabolites 2-methylbutyl acetate and methyl 2-methylbutyrate, which are reported to exhibit antimicrobial activity, were elevated in co-culture only. Conclusion: The observed VOCs were able to differentiate axenic and co-cultures. Validation of these markers in exhaled breath specimens could prove useful for timely pathogen identification and infection type diagnosis.
Found in: ključnih besedah
Summary of found: ...Introduction: Infections such as ventilator-associated pneumonia (VAP) can be...
Keywords: Bacteria, Enterobacter cloacae, Gas Chromatography-Mass Spectrometry, Infection, Pseudomonas aeruginosa, Volatile organic compounds
Published: 18.07.2019; Views: 166; Downloads: 9
.pdf Fulltext (1,29 MB)

5.
Exhaled breath metabolomics reveals a pathogen-specific response in a rat pneumonia model for two human pathogenic bacteria: a proof-of-concept study
Iain R White, Pouline M van Oort, 2019, original scientific article

Abstract: Volatile organic compounds in breath can reflect host and pathogen metabolism and might be used to diagnose pneumonia. We hypothesized that rats with Streptococcus pneumoniae (SP) or Pseudomonas aeruginosa (PA) pneumonia can be discriminated from uninfected controls by thermal desorption-gas chromatography-mass-spectrometry (TD-GC-MS) and selected ion flow tube-mass spectrometry (SIFT-MS) of exhaled breath. Male adult rats (n = 50) received an intratracheal inoculation of 1) 200 µl saline, or 2) 1 × 107 colony-forming units of SP or 3) 1 × 107 CFU of PA. Twenty-four hours later the rats were anaesthetized, tracheotomized, and mechanically ventilated. Exhaled breath was analyzed via TD-GC-MS and SIFT-MS. Area under the receiver operating characteristic curves (AUROCCs) and correct classification rate (CCRs) were calculated after leave-one-out cross-validation of sparse partial least squares-discriminant analysis. Analysis of GC-MS data showed an AUROCC (95% confidence interval) of 0.85 (0.73-0.96) and CCR of 94.6% for infected versus noninfected animals, AUROCC of 0.98 (0.94-1) and CCR of 99.9% for SP versus PA, 0.92 (0.83-1.00), CCR of 98.1% for SP versus controls and 0.97 (0.92-1.00), and CCR of 99.9% for PA versus controls. For these comparisons the SIFT-MS data showed AUROCCs of 0.54, 0.89, 0.63, and 0.79, respectively. Exhaled breath analysis discriminated between respiratory infection and no infection but with even better accuracy between specific pathogens. Future clinical studies should not only focus on the presence of respiratory infection but also on the discrimination between specific pathogens.
Found in: ključnih besedah
Summary of found: ...respectively. Exhaled breath analysis discriminated between respiratory infection and no infection but with even better...
Keywords: biomarkers, exhaled breath analysis, infection, pneumonia
Published: 22.07.2019; Views: 176; Downloads: 0
.pdf Fulltext (320,58 KB)

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