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Insights into complex nanopillar-bacteria interactions: Roles of nanotopography and bacterial surface proteins

Ishak MI, Jenkins J, Kulkarni S, Keller TF, Briscoe WH, Nobbs AH, et al.

J Colloid Interface Sci, 2021 Dec 15;604:91-103.
PMID: 34265695 DOI: 10.1016/j.jcis.2021.06.173

Nanopillared surfaces have emerged as a promising strategy to combat bacterial infections on medical devices. However, the mechanisms that underpin nanopillar-induced rupture of the bacterial cell membrane remain speculative. In this study, we have tested three medically relevant poly(ethylene terephthalate) (PET) nanopillared-surfaces with well-defined nanotopographies against both Gram-negative and Gram-positive bacteria. Focused ion beam scanning electron microscopy (FIB-SEM) and contact mechanics analysis were utilised to understand the nanobiophysical response of the bacterial cell envelope to a single nanopillar. Given their importance to bacterial adhesion, the contribution of bacterial surface proteins to nanotopography-mediated cell envelope damage was also investigated. We found that, whilst cell envelope deformation was affected by the nanopillar tip diameter, the nanopillar density affected bacterial metabolic activities. Moreover, three different types of bacterial cell envelope deformation were observed upon contact of bacteria with the nanopillared surfaces. These were attributed to bacterial responses to cell wall stresses resulting from the high intrinsic pressure caused by the engagement of nanopillars by bacterial surface proteins. Such influences of bacterial surface proteins on the antibacterial action of nanopillars have not been previously reported. Our findings will be valuable to the improved design and fabrication of effective antibacterial surfaces.
Tumour necrosis factor inhibitor survival and predictors of response in axial spondyloarthritis-findings from a United Kingdom cohort

Yahya F, Gaffney K, Hamilton L, Lonsdale E, Leeder J, Brooksby A, et al.

Rheumatology (Oxford), 2018 Apr 01;57(4):619-624.
PMID: 29272541 DOI: 10.1093/rheumatology/kex457

Objectives: To analyse long-term survival and efficacy of TNFi, reasons for switching or discontinuing, baseline predictors of response and remission in axial spondyloarthritis (axSpA) patients in a UK cohort.
Methods: All patients with a physician-verified diagnosis of axSpA attending two specialist centres who fulfilled the eligibility criteria for TNFi were included. Routinely recorded patient data were reviewed retrospectively. Initial TNFi was recorded as the index drug.
Results: Six hundred and fifty-one patients (94% AS) were included; adalimumab (n = 332), etanercept (n = 205), infliximab (n = 51), golimumab (n = 40) and certolizumab pegol (n = 23) were index TNFi. The mean (s.d.) duration from symptom onset to time of diagnosis was 8.6 (8.7) years and mean (s.d.) duration from diagnosis to TNFi initiation was 12.6 (11.5) years. A total of 224 (34.4%) stopped index TNFi, and 105/224 switched to a second TNFi. Median drug survival for index and second TNFi were 10.2 years (95% CI: 8.8, 11.6 years) and 5.5 years (95% CI: 2.7, 8.3 years), respectively (P < 0.05). Survival rates were not influenced by choice of TNFi. HLA-B27 predicted BASDAI50 and/or two or more point reduction within 6 months and long-term drug survival (P < 0.05). Low disease activity was predicted by non-smoking and low baseline BASDAI (P < 0.05).
Conclusion: We have observed good TNFi survival rates in axSpA patients treated in a real-life setting. This is best for first TNFi and not influenced by drug choice.
Resolving physical interactions between bacteria and nanotopographies with focused ion beam scanning electron microscopy

Jenkins J, Ishak MI, Eales M, Gholinia A, Kulkarni S, Keller TF, et al.

iScience, 2021 Jul 23;24(7):102818.
PMID: 34355148 DOI: 10.1016/j.isci.2021.102818

To robustly assess the antibacterial mechanisms of nanotopographies, it is critical to analyze the bacteria-nanotopography adhesion interface. Here, we utilize focused ion beam milling combined with scanning electron microscopy to generate three-dimensional reconstructions of Staphylococcus aureus or Escherichia coli interacting with nanotopographies. For the first time, 3D morphometric analysis has been exploited to quantify the intrinsic contact area between each nanostructure and the bacterial envelope, providing an objective framework from which to derive the possible antibacterial mechanisms of synthetic nanotopographies. Surfaces with nanostructure densities between 36 and 58 per μm2 and tip diameters between 27 and 50 nm mediated envelope deformation and penetration, while surfaces with higher nanostructure densities (137 per μm2) induced envelope penetration and mechanical rupture, leading to marked reductions in cell volume due to cytosolic leakage. On nanotopographies with densities of 8 per μm2 and tip diameters greater than 100 nm, bacteria predominantly adhered between nanostructures, resulting in cell impedance.
Fulltext Comment on: Tumour necrosis factor inhibitor survival and predictors of response in axial spondyloarthritis-findings from a United Kingdom cohort: reply

Yahya F, Gaffney K, Hamilton L, Lonsdale E, Leeder J, Brooksby A, et al.

Rheumatol Adv Pract, 2018;2(2):rky037.
PMID: 31433399 DOI: 10.1093/rap/rky037
Seagrass genomes reveal ancient polyploidy and adaptations to the marine environment

Ma X, Vanneste S, Chang J, Ambrosino L, Barry K, Bayer T, et al.

Nat Plants, 2024 Feb;10(2):240-255.
PMID: 38278954 DOI: 10.1038/s41477-023-01608-5

We present chromosome-level genome assemblies from representative species of three independently evolved seagrass lineages: Posidonia oceanica, Cymodocea nodosa, Thalassia testudinum and Zostera marina. We also include a draft genome of Potamogeton acutifolius, belonging to a freshwater sister lineage to Zosteraceae. All seagrass species share an ancient whole-genome triplication, while additional whole-genome duplications were uncovered for C. nodosa, Z. marina and P. acutifolius. Comparative analysis of selected gene families suggests that the transition from submerged-freshwater to submerged-marine environments mainly involved fine-tuning of multiple processes (such as osmoregulation, salinity, light capture, carbon acquisition and temperature) that all had to happen in parallel, probably explaining why adaptation to a marine lifestyle has been exceedingly rare. Major gene losses related to stomata, volatiles, defence and lignification are probably a consequence of the return to the sea rather than the cause of it. These new genomes will accelerate functional studies and solutions, as continuing losses of the 'savannahs of the sea' are of major concern in times of climate change and loss of biodiversity.