Search

Virulence of Pseudomonas aeruginosa involves the co-ordinate expression of a range of factors including type IV pili (tfp), the type III secretion system (TTSS) and quorum sensing. Tfp are required for twitching motility, efficient biofilm formation, and for adhesion and type III secretion (TTS)-mediated damage to mammalian cells. We describe a novel gene (fimL) that is required for tfp biogenesis and function, for TTS and for normal biofilm development in P. aeruginosa. The predicted product of fimL is homologous to the N-terminal domain of ChpA, except that its putative histidine and threonine phosphotransfer sites have been replaced with glutamine. fimL mutants resemble vfr mutants in many aspects including increased autolysis, reduced levels of surface-assembled tfp and diminished production of type III secreted effectors. Expression of vfr in trans can complement fimL mutants. vfr transcription and production is reduced in fimL mutants whereas cAMP levels are unaffected. Deletion and insertion mutants of fimL frequently revert to wild-type phenotypes suggesting that an extragenic suppressor mutation is able to overcome the loss of fimL. vfr transcription and production, as well as cAMP levels, are elevated in these revertants, while Pseudomonas quinolone signal (PQS) production is reduced. These results suggest that the site(s) of spontaneous mutation is in a gene(s) which lies upstream of vfr transcription, cAMP, production, and PQS synthesis. Our studies indicate that Vfr and FimL are components of intersecting pathways that control twitching motility, TTSS and autolysis in P. aeruginosa.

A new 130 to 140 Ma mafic dyke swarm, is identified in western South Africa. It consists of the previously undated Cederberg dyke swarm (CDS), for which we report U-Pb ID-TIMS baddeleyite ages of 131.4 ± 4.5 Ma (Knersvlake subswarm) and 133.0 ± 1.5 Ma (Doring-Tanqua subswarm). 40Ar/39Ar dates on these two samples and two additional dates of the Doring -- Tanqua subswarm cluster between 128.5 ± 1.4 Ma and 132.2 ± 1.5 Ma. We also report 40Ar/39Ar ages of 139.3 ± 3.5 Ma for an east-west trending dyke located further north: 27 km south of Kleinsee, and 140.3 ± 1.2 Ma for an east-west dyke near Garies. Together, these eight ages robustly date the emplacement of the northern part of a Greater Cederberg- False Bay Dyke Swarm (GCFDS) at ca. 130 to 140 Ma. Trace and rare earth element data reported herein suggest these dykes are compositionally E-MORB basalts that underwent modification either via subduction-modified lithospheric mantle, or by continental crust, or a combination thereof, and are petrogenetically similar to the ca. 132 Ma False Bay dykes around Cape Town. Therefore, we propose to unify all these coeval and compositionally similar dykes into one large igneous province (LIP) termed the Greater Cederberg-False Bay Large Igneous Province (GCF-LIP). [ABSTRACT FROM AUTHOR]

The objective of this study has been to develop technologies that can reduce the content of active pharmaceutical ingredients (APIs) and bacteria from hospital wastewater. The results from the laboratory- and pilot-scale testings showed that efficient removal of the vast majority of apis could be achieved by a membrane bioreactor (MBR) followed by ozone, ozone + hydrogen peroxide or powdered activated carbon (PAC). Chlorine dioxide (CIO2) was significantly less effective. MBR + PAC (450 mg/l) was the most efficient technology, while the most cost-efficient technology was MBR + ozone (156 mg O3/l applied over 20 min). With MBR an efficient removal of Escherichia coli and enterococci was measured, and no antibiotic resistant bacteria were detected in the effluent. With MBR + ozone and MBR + PAC also the measured effluent concentrations of APIs (e.g. ciprofloxacin, sulfamethoxazole and sulfamethizole) were below available predicted no-effect concentrations (PNEC) for the marine environment without dilution. lodinated contrast media were also reduced significantly (80-99% for iohexol, iopromide and ioversol and 40-99% for amidotrizoateacid). A full-scale MBR treatment plant with ozone at a hospital with 900 beds is estimated to require an investment cost of €1.6 mill, and an operating cost of €1/m3 of treated water. [ABSTRACT FROM AUTHOR]

Aberrant oncogene activation induces cellular senescence, an irreversible growth arrest that acts as a barrier against tumorigenesis. To identify microRNAs (miRNAs) involved in oncogene-induced senescence, we examined the expression of miRNAs in primary human TIG3 fibroblasts after constitutive activation of B-RAF. Among the regulated miRNAs, both miR-34a and miR-146a were strongly induced during senescence. Although members of the miR-34 family are known to be transcriptionally regulated by p53, we find that miR-34a is regulated independently of p53 during oncogene-induced senescence. Instead, upregulation of miR-34a is mediated by the ETS family transcription factor, ELK1. During senescence, miR-34a targets the important proto-oncogene MYC and our data suggest that miR-34a thereby coordinately controls a set of cell cycle regulators. Hence, in addition to its integration in the p53 pathway, we show that alternative cancer-related pathways regulate miR-34a, emphasising its significance as a tumour suppressor. [ABSTRACT FROM AUTHOR]

The objective of this study has been to develop technologies that can reduce the content of active pharmaceutical ingredients (APIs) and bacteria from hospital wastewater. The results from the laboratory- and pilot-scale testings showed that efficient removal of the vast majority of apis could be achieved by a membrane bioreactor (MBR) followed by ozone, ozone + hydrogen peroxide or powdered activated carbon (PAC). Chlorine dioxide (CIO2) was significantly less effective. MBR + PAC (450 mg/l) was the most efficient technology, while the most cost-efficient technology was MBR + ozone (156 mg O3/l applied over 20 min). With MBR an efficient removal of Escherichia coli and enterococci was measured, and no antibiotic resistant bacteria were detected in the effluent. With MBR + ozone and MBR + PAC also the measured effluent concentrations of APIs (e.g. ciprofloxacin, sulfamethoxazole and sulfamethizole) were below available predicted no-effect concentrations (PNEC) for the marine environment without dilution. lodinated contrast media were also reduced significantly (80-99% for iohexol, iopromide and ioversol and 40-99% for amidotrizoateacid). A full-scale MBR treatment plant with ozone at a hospital with 900 beds is estimated to require an investment cost of €1.6 mill, and an operating cost of €1/m3 of treated water. [ABSTRACT FROM AUTHOR]

A multi-branched fluorogenic probe for the rapid and specific detection of Gram-negative bacteria is reported. Three Gram-negative-targeting azido-modified polymyxins were clicked onto a trivalent scaffold functionalised with the environmental green-emitting fluorophore 7-nitrobenz-2-oxa-1,3-diazole. The probe allowed wash-free detection of target bacteria with increased sensitivity and lower limits of detection compared to monovalent probes.

We report a series of fluorescent probes based on mycobacteria membrane-associated disruption peptide, containing either L- or D-amino acids which were originally designed to kill Mycobacterium tuberculosis via membrane disruption. These peptides were decorated with "always on" and environmentally sensitive fluorophores and showed the rapid and efficient labelling of Mycobacterium smegmatis , with labelling of Mycobacterium tuberculosis demonstrated by two of the probes.

In this article we use an existential media framework to explore the asynchronous, written and digital form of GP-patient communication that takes place through e-consultations in a Danish general practice context. This approach acknowledges e-consultation as more than a tool for information delivery and frames GP and patient not as skilful media users but as dependent co-existers: Both thrown into and trying to navigate the digital healthcare ecology. Through a thematic analysis of 38 semi-structured qualitative interviews with patients and GPs we carve out three themes unpacking the existential dimensions of e-consultation: 1. Patient and GP are placed in a Culture of non-stop connectivity and we show the ambivalences arising herein fostering both relief, reassurance and new insecurities. 2. Ethical challenges of responsible co-existence points to dilemmas of boundary setting and caring for self and co-exister in the digital encounter. 3. We-experiences illustrates the potential of e-consultation to signal GP presence, even when the GP is silent. We also discuss the existential ethics of care emerging from the contemporary digital healthcare ecology and call for empirically grounded studies of the existential dimensions tied to encounters in contemporary digital care infrastructures., (© 2024 The Author(s). Sociology of Health & Illness published by John Wiley & Sons Ltd on behalf of Foundation for the Sociology of Health & Illness.)

"Tandem" uncaging systems, in which a photolabile protecting group (PPG) is sensitized by an energy-harvesting antenna, may increase the photosensitivity of PPGs by several orders of magnitude for two-photon (2P) photorelease. Yet, they remain poorly accessible because of arduous multi-step synthesis. In this work, we design efficient tandem uncaging systems by (i) using a convenient assembly of the building blocks relying on click chemistry, (ii) introducing H-bonding induced proximity thus facilitating (iii) photoinduced electron transfer (PeT) as a cooperative mechanism. A strong two-photon absorber electron-donating quadrupolar antenna and various electron-accepting PPGs (mDEAC, MNI or MDNI) were clicked stepwise onto a "tweezer-shaped" pyrido-2,6-dicarboxylate platform whose H-bonding and π-stacking abilities were exploited to keep the antenna and the PPGs in close proximity. The different electron-accepting ability of the PPGs led to dyads with wildly different behaviors. Whilst the MDNI and MNI dyads showed poor dark stability or no photo-uncaging ability due to their too high electron-accepting character, the mDEAC dyad benefited from optimum redox potentials to promote PeT and slow down charge recombination, resulting in enhanced uncaging quantum yield (Φ u =0.38) compared to mDEAC (Φ u =0.014). This unique combination resulted in large 2P photo-sensitivity in the near-infrared window (240 GM at 710 nm)., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Most COVID-19 vaccines elicit immunity against the SARS-CoV-2 Spike protein. However, Spike protein mutations in emerging strains and immune evasion by the SARS-CoV-2 virus demonstrates the need to develop more broadly targeting vaccines. To facilitate this, we use mass spectrometry to identify immunopeptides derived from seven relatively conserved structural and non-structural SARS-CoV-2 proteins (N, E, Nsp1/4/5/8/9). We use two different B-lymphoblastoid cell lines to map Human Leukocyte Antigen (HLA) class I and class II immunopeptidomes covering some of the prevalent HLA types across the global human population. We employ DNA plasmid transfection and direct antigen delivery approaches to sample different antigens and find 248 unique HLA class I and HLA class II bound peptides with 71 derived from N, 12 from E, 28 from Nsp1, 19 from Nsp4, 73 from Nsp8 and 45 peptides derived from Nsp9. Over half of the viral peptides are unpublished. T cell reactivity tested against 56 of the detected peptides shows CD8 + and CD4 + T cell responses against several peptides from the N, E, and Nsp9 proteins. Results from this study will aid the development of next-generation COVID vaccines targeting epitopes from across a number of SARS-CoV-2 proteins., (© 2024. The Author(s).)

In this study, we discuss how email consultations in general practice operate as a temporal technology, transforming working conditions and power relations between general practitioners (GPs) and patients. We draw on empirical material from Denmark in the form of a set of semi-structured interviews with 53 patients and 15 GPs, including two focus group discussions with 17 GPs. Our theoretical point of departure stems primarily from media theorist Sarah Sharma's (2014) concept of power-chronography, which describes how power is embedded in temporal relations and everyday life and secondarily from sociologist, Judy Wajcman's (2015) concept of multiple temporal landscapes. Patients and GPs calibrate their own time and attune their mutual time according to their expectations and ideas about the other party's time. The patient and the GP can both be viewed as 'time workers' and the email consultation as a digital technology fostering the recalibration of one person's time to that of another, requiring significant labour. The email consultation rearranges the GP-patient boundaries and thereby the power relations. Health institutions ought to consider whose time and labour is being 'saved' with digital systems.

A light-responsive polymer allowing the controlled release of camptothecin and the generation of reactive oxygen species (ROS) is reported. The polymer was prepared by controlled copolymerisation of water-soluble N , N -dimethyl acrylamide with a bromocoumarin methacrylate monomer. The lipophilic chemotherapy agent camptothecin was caged onto the coumarin unit via a photo-cleavable carbonate ester enabling light-triggered cargo release. The polymer showed good biocompatibility in the dark, and high cancer cell killing activity mediated both by the photo-release of camptothecin and ROS generation., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Decades of antibiotic misuse have led to alarming levels of antimicrobial resistance, and the development of alternative diagnostic and therapeutic strategies to delineate and treat infections is a global priority. In particular, the nosocomial, multidrug-resistant "ESKAPE" pathogens such as Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp (VRE) urgently require alternative treatments. Here, we developed light-activated molecules based on the conjugation of the FDA-approved photosensitizer riboflavin to the Gram-positive specific ligand vancomycin to enable targeted antimicrobial photodynamic therapy. The riboflavin-vancomycin conjugate proved to be a potent and versatile antibacterial agent, enabling the rapid, light-mediated, killing of MRSA and VRE with no significant off-target effects. The attachment of riboflavin on vancomycin also led to an increase in antibiotic activity against S. aureus and VRE. Simultaneously, we evidenced for the first time that the flavin subunit undergoes an efficient photoinduced bond cleavage reaction to release vancomycin, thereby acting as a photoremovable protecting group with potential applications in drug delivery., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)