Membrane Width Research Articles

Ethanol mass transfer model of spiral-wound membrane module with PDMS membrane for pervaporation considering module structure parameters

Pervaporation mass transfer model of spiral-wound membrane module with polydimethylsiloxane (PDMS) membrane considering module structure parameters has been developed for ethanol separation. Membrane intrinsic parameters involved mass transfer including limiting diffusivity of ethanol, plasticization coefficient of ethanol and partition coefficient were firstly determined, and then the model was verified by the experimental results with a correlation coefficient of 0.998. It has been calculated that bulk ethanol concentration (xe) would be decreased from 9 v/v% to 7.26 v/v% along the flow direction, under the ethanol feeding concentration of 9 v/v%, feeding velocity of 0.008 ms−1, membrane length of 1 m, membrane width of 1.5 m, channel height of 1.2 mm, if polydimethylsiloxane/polyamide (PDMS/PA) membrane was applied. Owing to the concentration-dependence of the membrane mass transfer coefficient (km), km and local ethanol flux (Je) was also decreased from 7.20 × 10-6 m·s-1to 7.07 × 10-6 m·s−1, and 386 g·m−2·h−1 to 306 g·m−2·h−1, respectively. For polydimethylsiloxane/polyvinylidene difluoride/Polyethylene terephthalate (PDMS/PVDF/PET) membrane, km and Je were decreased from 7.72 × 10-7 m·s-1to 7.65 × 10-7 m·s−1, and 137 g·m−2·h-1to 128 g·m−2·h−1, respectively, under the same condition. Higher ethanol feeding concentration and longer module would lead to more obvious change in xe, km and Je. While higher feeding velocity would lead to weaker change in xe, km and Je.

Curved and Annular Diaphragm Coupled Piezoelectric Micromachined Ultrasonic Transducers for High Transmit Biomedical Applications.

In this paper, we present a novel three-dimensional (3D) coupled configuration of piezoelectric micromachined ultrasound transducers (pMUTs) by combing a curved and an annular diaphragm for transmit performance optimization in biomedical applications. An analytical equivalent circuit model (EQC) is developed with varied excitation methods to incorporate the acoustic-structure coupling of the curved and annular diaphragm-coupled pMUTs (CAC-pMUTs). The model-derived results align well with the reference simulated by the finite element method (FEM). Using this EQC model, we optimize the key design parameters of the CAC-pMUTs in order to improve the output sound pressure, including the width of the annular membrane, the thickness of the passive layer, and the phase difference of the driving voltage. In the anti-phase mode, the designed CAC-pMUTs demonstrate a transmit efficiency 285 times higher than that of single annular pMUTs. This substantial improvement underscores the potential of CAC-pMUTs for large array applications.

Drag reduction using a self-adaptive flexible coating

We investigated the drag-reducing capabilities of a flexible coating on a rigid bluff body. Conducted in a wind tunnel, our experiments employed a rigid plate coated with a polyethylene membrane of various widths. The results indicated that the drag reduction, contingent on the membrane width, could reach up to 22.2%. Smoke-wire visualization corroborated the delay in flow separation and the emergence of narrower wake structures. This effect is ascribed to the self-adaptation of the flexible membrane to the fluid dynamics. Our study reveals that such passive flow control mechanisms are highly effective in complex, turbulent, three-dimensional flow conditions.

Prediction of the antigenic regions in eight RhD variants identified by computational biology.

Changes in RHD generate variations in protein structure that lead to antigenic variants. The classical model divides them into quantitative (weak and Del) and qualitative (partial D). There are two types of protein antigens: linear and conformational. Computational biology analyses the theoretical assembly of tertiary protein structures and allows us to identify the 'topological' differences between isoforms. Our aim was to determine the theoretical antigenic differences between weak RhD variants compared with normal RhD based on structural analysis using bioinformatic techniques. We analysed the variations in secondary structures and hydrophobicity of RHD*01, RHD*01W.1, W2, W3, RHD*09.03.01, RHD*09.04, RHD*11, RHD*15 and RHD*21. We then modelled the tertiary structure and calculated their probable antigenic regions, intra-protein interactions, displacement and membrane width and compared them with Rhce. The 10 proteins are similar in their secondary structure and hydrophobicity, with the main differences observed in the exofacial coils. We identified six potential antigenic regions: one that is unique to RhD (R3), one that is common to all D (R6), three that are highly variable among RhD isoforms (R1, R2 and R4), one that they share with Rhce (R5) and two that are unique to Rhce (Ra and Rbc). The alloimmunization capacity of these subjects could be explained by the variability of the antigen pattern, which is not necessarily recognized or recognized with lower intensity by the commercially available antibodies, and not because they have a lower protein concentration in the membrane.

Abstract 16909: Eicosapentaenoic Acid and Docosahexaenoic Acid Have Competing Effects on Membrane Lipid Dynamics Due to Differences in Structure

Background: Omega-3 fatty acids (n3-FAs) incorporate into vascular cell membranes where they modulate protein function and signal transduction. The n3-FA eicosapentaenoic acid (EPA) delivered in ethyl ester form (icosapent ethyl) reduced a broad range of cardiovascular events in high-risk patients (REDUCE-IT). This was not observed with mixed n3-FA formulations containing docosahexaenoic acid (DHA) in STRENGTH and other trials. These discordant outcomes indicate DHA may counter certain EPA effects due to its additional carbons and double bond. We compared these n3-FA effects on membrane lipid dynamics and width, key determinants of protein function. Methods: Membrane lipid fluidity was measured by fluorescence anisotropy approaches in large unilamellar vesicles (LUVs) of 100 nm diameter containing 1-palmitoyl-2-oleoyl-3-sn-phosphatidylcholine (POPC) and 50 mol% cholesterol with EPA and/or DHA (0-10 mol%). LUVs were treated with the fluorescent probe, 1,6-diphenyl-1,3,5-hexatriene (DPH), at 1 mol% and evaluated using a spectrofluorometer with a polarization accessory. Membrane width ( i.e ., unit cell periodicity) of the samples was determined by small angle x-ray scattering (SAXS). Results: DHA alone increased bulk lipid fluidity as indicated by a dose-dependent reduction in apparent rotational correlation time (ARCT); at 10 mol%, there was a ~20% (p<0.05) reduction from ~19 to ~16 nsec compared to control (untreated membranes). By contrast, EPA had no significant disordering effect except when combined at equimolar levels; the EPA/DHA combination showed a reduction in ARCT to ~18 nsec at 10 mol% that was different from EPA alone (p<0.05). Consistent with these findings, SAXS analysis showed DHA containing membranes had a reduced width compared to EPA by 5% or 3 Å (p<0.05) due to increased trans-gauche isomerizations in the phospholipid acyl chains. Conclusion: EPA maintained membrane fluidity while DHA increased fluidity and thereby reduced membrane width due to its additional carbons and double bond. The EPA/DHA combination increased membrane fluidity compared to control and EPA alone. The disordering effects of DHA may counter EPA stabilizing effects and explain discordant clinical outcomes with different n3-FA formulations.

Associations of Biomarkers of Tubular Injury and Inflammation with Biopsy Features in Type 1 Diabetes.

Whether biomarkers of tubular injury and inflammation indicate subclinical structural kidney pathology early in type 1 diabetes remains unknown. We investigated associations of biomarkers of tubular injury and inflammation with kidney structural features in 244 adults with type 1 diabetes from the Renin-Angiotensin System Study, a randomized, placebo-controlled trial testing effects of enalapril or losartan on changes in glomerular, tubulointerstitial, and vascular parameters from baseline to 5-year kidney biopsies. Biosamples at biopsy were assessed for kidney injury molecule 1 (KIM-1), soluble TNF receptor 1 (sTNFR1), arginine-to-citrulline ratio in plasma, and uromodulin and epidermal growth factor (EGF) in urine. We examined cross-sectional correlations between biomarkers and biopsy features and baseline biomarker associations with 5-year changes in biopsy features. Participants' mean age was 30 years (SD 10) and diabetes duration 11 years (SD 5); 53% were women. The mean GFR measured by iohexol disappearance was 128 ml/min per 1.73 m 2 (SD 19) and median urinary albumin excretion was 5 μ g/min (interquartile range, 3-8). KIM-1 was associated with most biopsy features: higher mesangial fractional volume (0.5% [95% confidence interval (CI), 0.1 to 0.9] greater per SD KIM-1), glomerular basement membrane (GBM) width (14.2 nm [95% CI, 6.5 to 22.0] thicker), cortical interstitial fractional volume (1.1% [95% CI, 0.6 to 1.6] greater), fractional volume of cortical atrophic tubules (0.6% [95% CI, 0.2 to 0.9] greater), and arteriolar hyalinosis index (0.03 [95% CI, 0.1 to 0.05] higher). sTNFR1 was associated with higher mesangial fractional volume (0.9% [95% CI, 0.5 to 1.3] greater) and GBM width (12.5 nm [95% CI, 4.5 to 20.5] thicker) and lower GBM surface density (0.003 μ m 2 / μ m 3 [95% CI, 0.005 to 0.001] lesser). EGF and arginine-to-citrulline ratio correlated with severity of glomerular and tubulointerstitial features. Baseline sTNFR1, uromodulin, and EGF concentrations were associated with 5-year glomerular and tubulointerstitial feature progression. Biomarkers of tubular injury and inflammation were associated with kidney structural parameters in early type 1 diabetes and may be indicators of kidney disease risk. Renin Angiotensin System Study (RASS/B-RASS), NCT00143949. This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_11_17_CJN0000000000000333.mp3.

Measurement of some body parts of muscovy duck (Carina moschata) at age 3 weeks old fed by pellet feed under an intensive farming system

This study was aimed to measure and determine the size of some body parts of the muscovy duck (Carina moschata) and their relationship with body weight. The research was be carried out for two months from August to September 2023 in local Intensive Muscovy Duck farm, Kademangan area, Blitar, East Java. The research material use were 60 muscovy ducks (unsexed), aged 3 weeks old, and reared in intensive farming system. This study used experiment quantitative methods (measurement). Muscovy duck sampling was carried out by random sampling. The variables observed were body weight, beak length, beak width, head length, head circumference, neck length, neck circumference, wing length, back length, chest length, chest width, shank length, shank circumference, and leg membrane width. Measurements were made on each individual using a measuring tape. The data obtained were tabulated and analyzed using normality test, correlation test and regression test. The results showed that there is a positive correlation between the morphological dimensions of livestock, including membrane width, shank length, beak width, wing length, head width, head length, neck length, shank circumference, beak length, breast length, breast width, neck circumference, back length, and body weight. And the length of the back has the largest contribution of 54% to the body weight of muscovy ducks (Carina moschata) aged 3 weeks old.

Kármán Vortex Street Driven Membrane Triboelectric Nanogenerator for Enhanced Ultra-Low Speed Wind Energy Harvesting and Active Gas Flow Sensing.

Wind energy harvesting and sensing have a huge prospect in constructing self-powered sensor nodes, but the energy transducing efficiency at low and ultra-low wind speeds is still limited. Herein, we proposed a Kármán vortex street driven membrane triboelectric nanogenerator (KVSM-TENG) for ultra-low speed wind energy harvesting and flow sensing. By introducing Kármán vortex in the KVSM-TENG, the cut-in wind speed of the KVSM-TENG decreased from 1 to 0.52 m/s that is the lowest cut-in wind speed in current TENGs. The instantaneous output density of the KVSM-TENG significantly increased by 1000 times and 2.65 times at the inlet wind speeds of 1 and 2 m/s, respectively. In addition, with the excellent energy transducing performance at the ultra-low speed range, the KVSM-TENG was successfully demonstrated to detect a weak leakage of gas pipeline (∼0.6 m/s) for alarming with high sensitivity. The interaction mechanism between the vortex and KVSM-TENG was systematically investigated. Through the simulation and experimental validation, the enhancement mechanism of vortex dependence on the cylinder diameter and placement location of KVSM-TENG was investigated in detail. The influence of parameters such as membrane length, width, thickness, and electrode gap on the performance of the KVSM-TENG was systematically studied. This work not only provided an ingenious strategy for ultra-low speed wind energy harvesting but also demonstrates the promising prospects for monitoring the air flow in the natural gas exploitation and transportation.

Optimisation of design and operating parameters of reverse osmosis process for the removal of phenol from wastewater

Reverse Osmosis (RO) is widely used for separating organic and inorganic pollutants in wastewater. In this research, the one-dimensional steady state model of a spiral wound RO for the removal of phenol from wastewater, was simulated using gPROMS software to identify optimal design and operating parameters. The design parameters included the membrane length, width and feed spacer channel and operating conditions included temperature and pressure of the RO process. The optimal design parameters were able to maximise the removal of phenol from wastewater. The simulation results showed that the removal of phenol from wastewater was significantly influenced by the combination of membrane width, operating pressure, and feed temperature. The four main parameters (permeate concentration, solute flow, solute rejection, and water flux) that govern the performance of a reverse osmosis membrane were found to be influenced by the design and operating conditions.

A Cadaveric Limb Analysis of the Posterior Tibial Musculotendinous Junction to determine the feasibility of Interosseous Membrane Tendon Transfer

The transfer of the posterior tibial tendon through the interosseous membrane is potentially an effective treatment to correct the deformity of the foot and ankle. Our study aimed to evaluate the anatomical feasibility of anterior transfer of the posterior tibial tendon through the interosseous membrane route using the musculotendinous junction (MTJ). Eighteen adult cadavers were used. The width and thickness of the tibial posterior MTJ, width of the interosseous membrane at the corresponding level, and the window size of the interosseous membrane were measured. Additionally, the distance between the distal end of the MTJ and the tip of the medial malleolus were recorded. The mean length of the posterior tibial tendon was 83.60 mm, the mean distance of the posterior tibial MTJ to medial malleolus tip was 45.48 mm and the mean length of MTJ was 31.74 mm. The mean width of distal end of MTJ was 7.76 mm, thickness of distal end of MTJ was 4.07 mm and the mean width of the interosseous membrane at the distal end of MTJ was 4.76 mm. We found the mean width of the proximal end of MTJ was 20.68 mm, the mean thickness of proximal end of MTJ was 5.52 mm, and mean width of interosseous membrane at the proximal end of MTJ was 8.76 mm. Our study has demonstrated that a 31 mm length incision made at approximately 45 mm from the proximal end of the medial malleolus can safely reach the MTJ. We recommend an opening length of the interosseous membrane of at least 20 mm.

Characteristics of indusia and sori in the two subspecies of Pteridium aquilinum (L.) Kuhn. occurring in Poland

Abstract Two subspecies of Pteridium aquilinum (L.) Kuhn: subsp. aquilinum and subsp. pinetorum occurring in Poland have been studied with respect to their micromorphological traits, in order to facilitate their differentiation. The micromorphology of marginal sori typical to Pteridium are described. Differences were found in the width of the outer membrane of indusium, the features of its edge (straight/notched) and the size and shape of the indusium cells. Moreover, the differentiating features turned out to be the frequency and length of the cillia on the edge of the indusium.

Integration of high-temperature PEMFC with air gap membrane distillation for simultaneous electricity generation and seawater desalination: A theoretical investigation

A novel hybrid system integrating high-temperature proton exchange membrane fuel cell (HT-PEMFC) with air gap membrane distillation (AGMD) is proposed to cogenerate electricity and freshwater. A mathematical model is established to evaluate the proposed system performance from both exergetic and energetic perspectives considering various irreversible effects, from which effectiveness and practicality of the proposed system are examined. Calculation examples reveal that maximum power density of the integrated system allows 83.4 % greater than that of the basic HT-PEMFC system, meanwhile, the according exergy destruction rate density is declined by 3.14 %. Furthermore, considerable sensitivity analyses indicate that the proposed system performance is benefited by elevating the feed water temperature while worsened by increasing the coolant water temperature, air gap width and thickness of hydrophobic membrane or feed water NaCl concentration. The feasibility of AGMD as an effective exhaust heat harvesting alternative is proved. The results acquired may be helpful in designing and optimizing such an actual hybrid system.

Molecular programs associated with glomerular hyperfiltration in early diabetic kidney disease

Hyperfiltration is a state of high glomerular filtration rate (GFR) observed in early diabetes that damages glomeruli, resulting in an iterative process of increasing filtration load on fewer and fewer remaining functional glomeruli. To delineate underlying cellular mechanisms of damage associated with hyperfiltration, transcriptional profiles of kidney biopsies from Pima Indians with type 2 diabetes with or without early-stage diabetic kidney disease were grouped into two hyperfiltration categories based on annual iothalamate GFR measurements. Twenty-six participants with a peak GFR measurement within two years of biopsy were categorized as the hyperfiltration group, and 26 in whom biopsy preceded peak GFR by over two years were considered pre-hyperfiltration. The hyperfiltration group had higher hemoglobin A1c, higher urine albumin-to-creatinine ratio, increased glomerular basement membrane width and lower podocyte density compared to the pre-hyperfiltration group. A glomerular 1240-gene transcriptional signature identified in the hyperfiltration group was enriched for endothelial stress response signaling genes, including endothelin-1, tec-kinase and transforming growth factor-β1 pathways, with the majority of the transcripts mapped to endothelial and inflammatory cell clusters in kidney single cell transcriptional data. Thus, our analysis reveals molecular pathomechanisms associated with hyperfiltration in early diabetic kidney disease involving putative ligand-receptor pairs with downstream intracellular targets linked to cellular crosstalk between endothelial and mesangial cells.

398-P: KIM-1 and TNFR 1 and Associations with Early Diabetic Nephropathy Histology

Aim: GFR and urine albumin excretion (UAE) are prevailing measures used to detect and monitor diabetic nephropathy (DN) . We tested whether serum kidney injury molecule-1 (KIM-1) and tumor necrosis factor receptor-1 (TNFR1) , markers of DN progression, are associated with DN renal structural parameters in persons with TIDM. Methods: We measured KIM-1 and TFNR1 in 285 participants from the Renin Angiotensin System Study (RASS) . Participants had T1DM for 2-20 yrs and were free of any clinical DN. Baseline iGFR and kidney biopsies were obtained. We used linear regression to estimate cross-sectional associations of markers with renal structural measures. Results: Mean age was 30 ± yrs; mean iGFR was 125 ± 18 ml/min/1.73 m2; median UAE was 5 (IQR 4- 7) . Higher KIM-1 was associated with significantly greater mesangial fraction volume [Vv (Mes/glom) ] and the tubular atrophy (table 1) . Higher TNFR1 was associated with significantly higher Vv (Mes/glom) and glomerular basement membrane (GBM) width. Neither iGFR nor UAE were significantly associated with lesions. Conclusion: Serum KIM-1 and TNFR1 were associated with higher values for Vv (Mes/glom) , GBM, and tubular atrophy in persons with T1DM and normal kidney function, suggesting relevance as markers of early DN structural changes prior to UAE elevation or GFR decline. KIM-1 is specific to the tubules, highlighting the importance of characterizing the natural history of tubular functions in DN. Disclosure F.Tian: None. D.Prince: None. A.Doria: Research Support; Novo Nordisk Foundation. M.Mauer: None. B.Kestenbaum: Consultant; Reata Pharmaceuticals, Inc. Funding T32

EFFECT OF ORAL CARBONIC ANHYDRASE INHIBITOR ON CYSTOID MACULAR EDEMA ASSOCIATED WITH RETINITIS PIGMENTOSA: An OCT and OCT Angiography Study.

To investigate the factors associated with visual improvement in response to oral carbonic anhydrase inhibitors (CAIs) and the occurrence of microvascular changes in patients with retinitis pigmentosa-associated cystoid macular edema (RP-CME). This retrospective cohort study included 59 eyes from 39 patients with RP-CME who underwent at least 3 months of oral CAI treatment. The eyes were divided into responding and nonresponding groups based on optical coherence tomography (OCT) criteria (resolution of cyst and reduction of foveal or parafoveal volume). All eyes were assessed before and after treatment using OCT and OCT angiography. Thirty-three eyes (55.9%) demonstrated a positive response to treatment, and 26 eyes (44.1%) did not. Compared with nonresponding eyes, responding eyes had a significantly higher frequency of multilayer CME than CME limited to the inner nuclear layer ( P = 0.016). Subgroup analysis within the responding group revealed that improvements in visual acuity were more likely in eyes with fovea-involving CME and a higher baseline external limiting membrane and ellipsoid zone width. Microvascular parameters showed no significant changes after treatment. Eyes with CME extending to the outer nuclear layer or central fovea, and higher initial photoreceptor integrity may be prognostic factors associated with structural and functional improvements after carbonic anhydrase inhibitors treatment. Early treatment of multilayer CME with foveal involvement seems to be crucial in preventing irreversible photoreceptor damage.

MO399: Remodel: A Mechanistic Trial Evaluating the Effects of Semaglutide on the Kidneys In People With Type 2 Diabetes and Chronic Kidney Disease

Abstract BACKGROUND AND AIMS Approximately 40% of people with type 2 diabetes (T2D) develop chronic kidney disease (CKD) and, despite current treatment, T2D is the most common cause of progression to kidney failure. This situation underscores the need for additional pharmacotherapeutic options. Analyses of cardiovascular outcomes trials suggest that glucagon-like peptide-1 receptor agonists (GLP-1RAs), such as semaglutide, lower albuminuria and attenuate estimated glomerular filtration rate (eGFR) decline in people with T2D. Previous analyses suggest that GLP-1RAs reduce hypoxia and inflammation and, thereby, have a mode of action on the kidneys that is distinct from other treatments, such as sodium-glucose cotransporter-2 (SGCT-2) inhibitors and renin–angiotensin–aldosterone system (RAAS) blockers. Furthermore, the primary benefit of semaglutide appears to be in people with an eGFR < 60 mL/min/1.73 m2, a group in which there is a significant residual risk of progression and a consequent unmet need for effective treatment. To gain further insights on the kidney-protective mechanism of action of semaglutide, the REMODEL trial is integrating investigative functional kidney magnetic resonance imaging (MRI) and kidney biopsies; recent developments in these techniques permit elucidation of the mechanisms underlying kidney protection with current therapies. Mechanistic findings of the REMODEL trial will complement those of the ongoing FLOW clinical trial, which is designed to evaluate clinical outcomes in people with T2D and CKD treated with once-weekly (OW) subcutaneous semaglutide. METHOD REMODEL (NCT04865770) is a 52-week, multicentre, international clinical trial (Figure 1). Primary endpoints are MRI-based and include change from baseline to week 52 in kidney oxygenation (measured with BOLD MRI R2*), global kidney perfusion (phase-contrast MRI) and kidney inflammation (T1 Mapping MRI). Secondary endpoints evaluated from kidney biopsies in a nested cohort (n ∼ 45) include change from baseline to week 52 in intrarenal mRNA expression, assessed by single-nucleus transcriptomics and glomerular basement membrane width, assessed by morphometry. Other secondary endpoints include the apparent diffusion coefficient (estimating renal fibrosis; evaluated with diffusion-weighted MRI), natriuresis, albumin excretion rate and creatinine clearance. MRI outcomes will also be evaluated at week 4 to identify potential early effects of semaglutide in the kidney. Examples of MRI and kidney biopsy single-cell gene expression profile data from participants with CKD are shown in Figure 2 (data not from REMODEL). Safety will be assessed throughout the trial. RESULTS REMODEL was initiated in April 2021 and is being conducted in Canada, France, Italy, Poland, South Africa, Spain and USA. CONCLUSION REMODEL will investigate the effect of the GLP-1RA semaglutide on inflammatory and hypoxia-related pathways in the kidney. The combination of MRI and tissue-level interrogation with biopsies will complement standard laboratory findings, enabling the identification of cells and pathways involved in kidney disease and protection. The trial will provide valuable mechanistic insights on the use of OW semaglutide in people with T2D and CKD and may stimulate the development of a precision medicine approach to the management of such individuals. In addition, REMODEL will complement the findings of the FLOW trial.

Investigating Structural Dynamics of KCNE3 in Different Membrane Environments Using Molecular Dynamics Simulations.

KCNE3 is a potassium channel accessory transmembrane protein that regulates the function of various voltage-gated potassium channels such as KCNQ1. KCNE3 plays an important role in the recycling of potassium ion by binding with KCNQ1. KCNE3 can be found in the small intestine, colon, and in the human heart. Despite its biological significance, there is little information on the structural dynamics of KCNE3 in native-like membrane environments. Molecular dynamics (MD) simulations are a widely used as a tool to study the conformational dynamics and interactions of proteins with lipid membranes. In this study, we have utilized all-atom molecular dynamics simulations to characterize the molecular motions and the interactions of KCNE3 in a bilayer composed of: a mixture of POPC and POPG lipids (3:1), POPC alone, and DMPC alone. Our MD simulation results suggested that the transmembrane domain (TMD) of KCNE3 is less flexible and more stable when compared to the N- and C-termini of KCNE3 in all three membrane environments. The conformational flexibility of N- and C-termini varies across these three lipid environments. The MD simulation results further suggested that the TMD of KCNE3 spans the membrane width, having residue A69 close to the center of the lipid bilayers and residues S57 and S82 close to the lipid bilayer membrane surfaces. These results are consistent with previous biophysical studies of KCNE3. The outcomes of these MD simulations will help design biophysical experiments and complement the experimental data obtained on KCNE3 to obtain a more detailed understanding of its structural dynamics in the native membrane environment.

Investigating Biomarkers for USH2A Retinopathy Using Multimodal Retinal Imaging.

Pathogenic mutations in USH2A are a leading cause of visual loss secondary to non-syndromic or Usher syndrome-associated retinitis pigmentosa (RP). With an increasing number of RP-targeted clinical trials in progress, we sought to evaluate the photoreceptor topography underlying patterns of loss observed on clinical retinal imaging to guide surrogate endpoint selection in USH2A retinopathy. In this prospective cross-sectional study, twenty-five patients with molecularly confirmed USH2A-RP underwent fundus autofluorescence (FAF), spectral-domain optical coherence tomography (SD-OCT) and adaptive optics scanning laser ophthalmoscopy (AOSLO) retinal imaging. Analysis comprised measurement of FAF horizontal inner (IR) and outer (OR) hyperautofluorescent ring diameter; SD-OCT ellipsoid zone (EZ) and external limiting membrane (ELM) width, normalised EZ reflectance; AOSLO foveal cone density and intact macular photoreceptor mosaic (IMPM) diameter. Thirty-two eyes from 16 patients (mean age ± SD, 36.0 ± 14.2 years) with USH2A-associated Usher syndrome type 2 (n = 14) or non-syndromic RP (n = 2) met the inclusion criteria. Spatial alignment was observed between IR-EZ and OR-ELM diameters/widths (p < 0.001). The IMPM border occurred just lateral to EZ loss (p < 0.001), although sparser intact photoreceptor inner segments were detected until ELM disruption. EZ width and IR diameter displayed a biphasic relationship with cone density whereby slow cone loss occurred until retinal degeneration reached ~1350 μm from the fovea, beyond which greater reduction in cone density followed. Normalised EZ reflectance and cone density were significantly associated (p < 0.001). As the strongest correlate of cone density (p < 0.001) and best-corrected visual acuity (p < 0.001), EZ width is the most sensitive biomarker of structural and functional decline in USH2A retinopathy, rendering it a promising trial endpoint.

Effect of MαCD-mediated phospholipid exchange on plasma membrane ordered lipid domain stability

Using methyl-α-cyclodextrin (MαCD) mediated outer leaflet phospholipid exchange in cells, we recently showed insulin receptor (IR) activity in CHO cells was supported after substitution replacing plasma membrane outer leaflet lipids with sphingomyelin, which has a propensity to form ordered domains, but inhibited upon substitution with unsaturated phosphatidylcholines (PC), which tend to form disordered domains. We also showed IR activity increased as membrane width increased, as seen when plasma membrane outer leaflet lipids were replaced with saturated PCs with different length acyl chains.

In-situ high-resolution 3D imaging combined with proteomics and metabolomics reveals enlargement of subcellular architecture and enhancement of photosynthesis pathways in nuclear-irradiated Chlorella pyrenoidosa

• In-situ 3D architectures of C. pyrenoidosa was visualized by FIB-SEM and cryo-ET. • Fine architectures and volume increase of subcellular organelles were observed. • Proteomics and metabolomics reveal universal overexpression of Rubisco in the mutant. • Variation in thylakoid width suggest an upregulation in chloroplast construction. Chlorella pyrenoidosa is a microalga that holds enormous potential as a source of renewable energy. Nuclear radiation is commonly used to modify natural microalgal phenotypes to enhance specified functions. However, the mechanisms underlying such modifications are poorly understood. Here, we use a multidisciplinary approach to analyze wild-type Chlorella pyrenoidosa and a nuclear-irradiated mutant known for its higher growth rate and photosynthetic efficiency. A combination of focused ion beam scanning electron microscopy (FIB-SEM), cryo-FIB milling, and cryo-electron tomography (cryo-ET) achieve visualization of the microalgae and their organelles in unprecedented detail. Compared to the wild-type cell, the nuclear-irradiated mutant and its subcellular organelles, including the chloroplast, significantly increase in volume by 1.2-fold. Moreover, proteomics and metabolomics data indicate rubisco overexpression by 1.07-fold in the mutant, consistent with enhancement of carbon fixation in photosynthesis and the observed enlargement of subcellular morphology. Furthermore, cryo-ET reveals enlarged membrane width in the thylakoid of the mutant, suggesting an upregulation role for chlorophyll synthesis and chloroplast construction. Collectively, our studies reveal the detailed architectures of C. pyrenoidosa wild-type and a mutant with higher growth rate and photosynthetic efficiency, providing a basis for understanding how subcellular organelles function collaboratively to support macroscopic traits.