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Cation selective channels constitute the gate for ion currents through the cell membrane. Here we present an improved statistical mechanical model based on atomistic structural information, cation hydration state and without tuned parameters that reproduces the selectivity of biological Na+ and Ca2+ ion channels. The importance of the inclusion of step-wise cation hydration in these results confirms the essential role partial dehydration plays in the bacterial Na+ channels. The model, proven reliable against experimental data, could be straightforwardly used for designing Na+ and Ca2+ selective nanopores.

Virtual healthcare has the potential to increase access to allied health for people living in rural areas, but challenges in delivery of such models have been reported. The COVID-19 pandemic provided an opportunity for a rural practice of physiotherapists and exercise physiologists to transition service delivery to a virtual model of care which utilised a combination of phone, video, an exercise app and/or paper handouts. This study aimed to evaluate the uptake and outcomes from virtual delivery of allied health services, and to describe patient and clinician experiences of the virtual model of care. A parallel convergent mixed methods study was conducted. De-identified data from patients who were offered the virtual service between 15 March 2020 and 30 September 2020 were extracted from the database of the rural practice, as were data from patients attending the practice in-person during the same time in 2019 to serve as a historical comparison. De-identified data from a monthly survey tracking clinician experiences of delivering care virtually was also obtained from the practice. Quantitative data were presented descriptively. Between-group differences were compared using independent samples t-tests, and within-group longitudinal changes compared using paired t-tests. Semi-structured interviews were conducted among a purposive sample of patients using the virtual service, and focus groups conducted among clinicians providing this model of care. Qualitative data were recorded and transcribed verbatim, then thematic analysis conducted. During the study period, the practice delivered 4% (n = 242) consultations virtually. Thirty-seven of the 60 patients (62%) using the virtual service were new referrals. Patients attended fewer sessional appointments virtually and a smaller proportion of patients reported high satisfaction with virtual care, compared to those who received in-person care the previous year (p < .05). Clinician confidence in delivering virtual care did not change significantly over time (p>.05), though clinicians not providing virtual care in a given month perceived their lower confidence than those who did provide virtual care (p < .05). Five themes influencing the success of virtual allied health provision emerged from patient interviews and clinician focus groups: adaptation of program elements for virtual delivery, conduct of virtual treatment, clinician flexibility, patient complexity and communication. The theme of communication influenced all the other themes. Virtual healthcare is a potential solution to address lack of access to allied health practitioners in rural areas, but may not suit all patients. Establishing a therapeutic relationship and ensuring people have access to adequate resources prior to virtual care delivery will optimise successful adoption of virtual care models. A hybrid model incorporating limited in-person consultations with virtual consultations appears a more viable option.

Mariprofundus ferrooxydans PV-1 has provided the first genome of the recently discovered Zetaproteobacteria subdivision. Genome analysis reveals a complete TCA cycle, the ability to fix CO(2), carbon-storage proteins and a sugar phosphotransferase system (PTS). The latter could facilitate the transport of carbohydrates across the cell membrane and possibly aid in stalk formation, a matrix composed of exopolymers and/or exopolysaccharides, which is used to store oxidized iron minerals outside the cell. Two-component signal transduction system genes, including histidine kinases, GGDEF domain genes, and response regulators containing CheY-like receivers, are abundant and widely distributed across the genome. Most of these are located in close proximity to genes required for cell division, phosphate uptake and transport, exopolymer and heavy metal secretion, flagellar biosynthesis and pilus assembly suggesting that these functions are highly regulated. Similar to many other motile, microaerophilic bacteria, genes encoding aerotaxis as well as antioxidant functionality (e.g., superoxide dismutases and peroxidases) are predicted to sense and respond to oxygen gradients, as would be required to maintain cellular redox balance in the specialized habitat where M. ferrooxydans resides. Comparative genomics with other Fe(II) oxidizing bacteria residing in freshwater and marine environments revealed similar content, synteny, and amino acid similarity of coding sequences potentially involved in Fe(II) oxidation, signal transduction and response regulation, oxygen sensation and detoxification, and heavy metal resistance. This study has provided novel insights into the molecular nature of Zetaproteobacteria.

BackgroundColonisation of sessile eukaryotic host surfaces (e.g. invertebrates and seaweeds) by bacteria is common in the marine environment and is expected to create significant inter-species competition and other interactions. The bacterium Pseudoalteromonas tunicata is a successful competitor on marine surfaces owing primarily to its ability to produce a number of inhibitory molecules. As such P. tunicata has become a model organism for the studies into processes of surface colonisation and eukaryotic host-bacteria interactions.Methodology/principal findingsTo gain a broader understanding into the adaptation to a surface-associated life-style, we have sequenced and analysed the genome of P. tunicata and compared it to the genomes of closely related strains. We found that the P. tunicata genome contains several genes and gene clusters that are involved in the production of inhibitory compounds against surface competitors and secondary colonisers. Features of P. tunicata's oxidative stress response, iron scavenging and nutrient acquisition show that the organism is well adapted to high-density communities on surfaces. Variation of the P. tunicata genome is suggested by several landmarks of genetic rearrangements and mobile genetic elements (e.g. transposons, CRISPRs, phage). Surface attachment is likely to be mediated by curli, novel pili, a number of extracellular polymers and potentially other unexpected cell surface proteins. The P. tunicata genome also shows a utilisation pattern of extracellular polymers that would avoid a degradation of its recognised hosts, while potentially causing detrimental effects on other host types. In addition, the prevalence of recognised virulence genes suggests that P. tunicata has the potential for pathogenic interactions.Conclusions/significanceThe genome analysis has revealed several physiological features that would provide P. tunciata with competitive advantage against other members of the surface-associated community. We have also identified properties that could mediate interactions with surfaces other than its currently recognised hosts. This together with the detection of known virulence genes leads to the hypothesis that P. tunicata maintains a carefully regulated balance between beneficial and detrimental interactions with a range of host surfaces.