Sarcomeres, the basic repeating unit of striated muscle, are joined together by crosslinked actin filaments found at the boundaries of muscle sarcomeres, termed Z-discs. Z-discs play a key role in cardiac signalling and disease, however, the arrangement and function of many of the proteins present in the Z-disc remain to be understood. Here, we determined the organisation of 3 key proteins, ZASP, ɑ-actinin-2 and the Z1Z2 epitope of titin, located within the Z-disc. We fluorescently labelled these proteins in cardiac myofibrils using Adhirons specific to each protein and used interferometric photoactivated localization microscopy (iPALM) to obtain the 3D position of these proteins to a high precision (<10nm in x,y,z). We then used PERPL (Pattern Extraction from Relative Positions of Localisations: available at https://github.com/oubino/z_disk/releases/tag/v0.0.3) to analyse patterns in the relative positions of the proteins and reveal their underlying organisation. This analysis revealed that ZASP and ɑ-actinin-2 have a similar repeating organisation, but that the organisation of Z1Z2 is different.

Extreme rainfall is intensifying globally as the climate continues to warm. Yet how such events affect coastal water quality and potentially influence assessments of water quality improvement remains poorly understood. This study uses time-series optical satellite observations to characterize the response and recovery of coastal water quality following the 2023 extreme rainfall event in the Bohai Sea and to evaluate how this short-term disturbance influences monthly assessments of water quality improvement. The event substantially increased suspended particulate matter (SPM), chlorophyll-a, colored dissolved organic matter, and Forel-Ule Index values, while reducing water transparency (Secchi disk depth, ZSD) and sea surface salinity. In particular, SPM increased by 173% relative to the pre-rainfall baseline. The proportions of highly turbid and diluted waters increased by 27 and 10 percentage points (pp), respectively. Across all indicators, the strongest changes were found in estuaries and nearshore waters. Responses peaked five days after the event, and all indicators returned to the pre-rainfall level within two weeks. Such dramatic and prolonged changes in water quality can alter monthly means, with the monthly ZSD assessment for August 2023 showing a sensitivity of 13 pp to disturbance-period observations. This finding emphasizes the importance to distinguish event-driven variability from longer-term water quality changes in marine environmental management.

Bioactive wound dressings with antibacterial properties are attractive for infection control. Phytochemicals, products from plant secondary metabolism, like gallic acid (GA), ferulic acid (FA), coumaric acid (CouA) and perillyl alcohol (PA) show promising antimicrobial activity, but their poor water solubility and the high concentrations required for efficacy limit their application. To overcome this, Natural Deep Eutectic Solvents (NADES) provide a sustainable and biocompatible alternative to conventional solvents. NADES were used at sub-minimum bactericidal concentrations (MBC) to enhance phytochemical antimicrobial activity against Staphylococcus epidermidis and Escherichia coli. CC:Gly (100%) dissolved all tested phytochemicals. GA + CC:Gly:CA (20%) against S. epidermidis, and AP, CouA and FA with CC:Gly (100%) against E. coli, reduced the MBC from ≥4000 to 2000 μg/mL. The most promising phytochemical-NADES formulations were encapsulated into electrospun zein nanofibres to fabricate sustainable bioactive wound dressings. All electrospinning solutions exhibited Newtonian behaviour, and their viscosity and conductivity strongly influenced fibre morphology: CC:Gly formulations produced rough fibres with larger diameters (1253 ± 57 nm), whereas CC:Gly:CA yielded smooth fibres with smaller diameters (419 ± 45 nm). In vitro release studies demonstrated complete GA release within 50 min, following a non-Fickian diffusion. FTIR indicated encapsulation through physical entrapment. Among the antimicrobial assays performed, disk diffusion demonstrated the most evident activity, with Z + GA + CC:Gly:CA producing an inhibition zone of 18.7 mm, although further optimisation is required to improve performance in liquid-based assays. Overall, this study demonstrates the role of NADES as phytochemical solubilisers and antimicrobial enhancers, as well as functional components of electrospun sustainable wound dressing applications.

Hypertrophic cardiomyopathy (HCM) is a primary disease of cardiac myocytes caused by mutations in genes encoding sarcomere proteins. The ensuing phenotype, however, is multicellular, induced by biological and functional changes in myocytes and non-myocyte cardiac cells, particularly fibroblasts. The molecular genetic basis of HCM has been partially elucidated, and over three dozen genes are implicated as causes of HCM. MYBPC3, which encodes myosin binding protein C3, is the most common causal gene, followed by MYH7, which encodes the β-myosin heavy chain (β-MYH or MYH7) protein. Approximately 35% to 40% of HCM cases are caused by mutations in the MYBPC3 and MYH7 genes. Mutations in genes encoding the thin filament, Z disk, and other sarcomere-associated proteins cause about 10% to 15% of HCM cases. Overall, the genetic discoveries identify HCM as a disease of sarcomere proteins. Nevertheless, the causal genes for a significant fraction of patients with clinically diagnosed HCM remain unknown. This, in part, may reflect the oligogenic nature of HCM in a subset of cases, phenocopy conditions, including overdiagnosis of HCM, and the current approach to genetic screening. Advances in the molecular genetic basis of HCM have ushered in the applications of genetic discoveries to care for patients with HCM, including genetic testing and the development of specific therapies that target the underpinning mechanism of HCM. Identification of additional causal genes and the development of new therapies, including genetic interventions to target and correct the causal mutation, are expected to further impact the clinical management of patients with HCM.

Antimicrobial resistance (AMR), largely driven by the inappropriate and excessive use of antibiotics, requires rapid and reliable bacterial detection and antibiotic susceptibility testing (AST), as conventional culture-based methods remain time-intensive. Here, we report a real-time, label-free interdigitated wave electrode array (IWEA) that combines dielectrophoretic (DEP) enrichment with impedance spectroscopy for rapid bacterial detection and AST. The proposed IWEA was designed and optimized via COMSOL Multiphysics to enhance DEP-relevant electric-field strength, thereby improving DEP-assisted bacterial enrichment compared to conventional planar interdigitated electrodes. The platform enabled sensitive detection of both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) in 0.1× PBS across 10-10[5] CFU/mL within 30 min using DEP-assisted preconcentration (100 kHz, 10 Vpp), outperforming passive (non-DEP) operation (10[2]-10[5] CFU/mL). For AST, bacterial responses to vancomycin, gentamicin, and ampicillin were monitored through impedance variations following DEP-based enrichment. Susceptible bacteria produced concentration-dependent reductions in ΔZ/Z0, whereas resistant bacteria showed similar responses to untreated controls. Quantitative assessment yielded CC50 values of 2.86 ± 0.22 µg/mL and 3.06 ± 0.20 µg/mL for vancomycin and gentamicin against S. aureus, and 4.59 ± 0.30 µg/mL for gentamicin against E. coli. Resistance profiles of S. aureus to ampicillin and E. coli to vancomycin and ampicillin were clearly distinguished. SEM imaging and disk diffusion assays independently validated the impedance-derived susceptibility results. Collectively, this IWEA platform offers a rapid, label-free, and quantitative approach for bacterial detection and AST, with strong potential for antimicrobial screening and point-of-care diagnostics.

Background/Objectives: The study addresses the global health challenge posed by multidrug-resistant (MDR) pathogens, highlighting the urgent need for alternative antimicrobial solutions. This study investigated the in vitro antimicrobial and antibiofilm potential of endophytic mediated-synthesized silver nanoparticles (AgNPs). Methods: An endophytic bacterium was isolated from the medicinal plant Commiphora gileadensis in Saudi Arabia and identified as Bacillus subtilis CG1 through 16S rRNA gene sequencing. The bacterium was utilized for the green synthesis of AgNPs, as confirmed by Ultraviolet-visible (UV-Vis) spectroscopy. AgNPs characterization was done using Fourier-transform infrared (FTIR) spectroscopy, Transmission and scanning electron microscopy (TEM and SEM), energy-dispersive X-ray spectroscopy (EDX), and dynamic light scattering (DLS). The antimicrobial efficacy of the fabricated AgNPs was tested against eight clinically relevant pathogens using standard in vitro assays such as the agar disk diffusion method, minimum inhibitory concentration (MIC), minimum bactericidal and fungicidal concentrations (MBC and MFC). Additionally, AgNPs were tested for antibiofilm activity against P. aeruginosa and S. epidermidis. Tested pathogens included Methicillin-Resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Candida auris, Candida albicans, and Candida tropicalis. The antibiofilm efficacy was tested using the Crystal violet assay. Results: UV-Vis spectroscopy confirmed AgNP formation with a characteristic absorption peak at 412 nm. FTIR analysis identified the presence of hydroxyl, nitrile, and alkyne functional groups, which are involved in nanoparticle reduction and stabilization. TEM and SEM revealed predominantly spherical AgNPs with sizes ranging from 17 to 72 nm, while EDX confirmed silver as the major elemental component. DLS analysis showed a Z-average particle size of 113.9 ± 67.75 nm and a zeta potential of -24.2 mV. The synthesized AgNPs exhibited concentration-dependent antimicrobial activity, producing inhibition zones of 10-20 mm at 240 µg/mL. MIC values ranged from 6.25 to 25 µg/mL, whereas MBC and MFC values ranged from 6.25 to 50 µg/mL and 25 to 100 µg/mL, respectively. Moreover, bacterial growth kinetics analysis demonstrated a concentration-dependent inhibition of growth by AgNPs at MIC and sub-MIC concentrations. Additionally, AgNPs demonstrated significant antibiofilm activity against P. aeruginosa and S. epidermidis.Conclusions: Overall, B. subtilis CG1-mediated AgNPs exhibited promising physicochemical properties and antimicrobial and antibiofilm activities, suggesting their potential as alternatives for combating resistant and biofilm-associated infections.

The cardiac β-myosin (MYH7) mutation E525K was identified in 2012 in a patient with dilated cardiomyopathy (DCM). Work using engineered constructs has shown that this mutation stabilizes the interacting heads motif (IHM) of myosin and increases the ATPase activity of mutant motor S1 heads. However, no measurements have been made in myofilaments or cardiomyocytes to determine its effect on contractile function. Here, we present force and contractile kinetics measurements from induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) engineered for heterozygous expression of E525K. Single-cell contraction for E525K hiPSC-CMs decreased by 65%, and isometric twitch force in engineered heart tissues (EHTs) decreased by 39%. In contrast, maximal Ca[2+] activated isometric force in isolated myofibrils increased by 45% and sub-maximal Ca[2+] activated force was similar to WT myofibrils. Structural analysis revealed reduced myofibril content (13.7% decrease) and decreased organization (increased z-disk dispersion angle) in E525K cells. We confirmed that E525K S1 myosin has higher actin affinity than WT S1 and elevated ATPase activity. However, there was no change in S1 ADP release rate. There was also no change in either the rate of force development or relaxation in myofibrils, cells, or EHTs. These findings suggest that E525K myosin crossbridge cycling is not altered during loaded contractions. To understand how twitch force of myocytes was reduced but maximal isometric force was increased, we used a spatially explicit sarcomere model. The results were explained by changing three rates: reduced recruitment from the OFF/IHM state, and increased rates of actin binding and Pi release. Additional force deficits in cells and EHTs likely result from the myofibrillar disorganization. This study demonstrates the value of multi-scale analysis and coupled, computational modeling to understand the molecular mechanisms of sarcomere mutations in cardiomyocytes.