Water-filled Channels Research Articles

Channel-facilitated transport under resetting dynamics.

The transport of particles through channels holds immense significance in physics, chemistry, and biological sciences. For instance, the motion of solutes through biological membranes is facilitated by specialized proteins that create water-filled channels. Valuable insights can be obtained by studying the transition paths of particles through a channel and gathering information on their lifetimes inside the channel as well as their exit probabilities. In a similar vein, we consider a one-dimensional model of channel-facilitated transport where a diffusive particle is subject to attractive interactions with the walls of the channel. We study the statistics of conditional and unconditional escape times in the presence of resetting-an intermittent dynamics that brings the particle back to its initial coordinate stochastically. We determine analytically the physical conditions under which such a resetting mechanism becomes beneficial for the faster escape of the particles from the channel, thus enhancing transport. Our theory has been verified with the aid of Brownian dynamics simulations for various interaction strengths and extents. The overall results presented herein highlight the scope of resetting-based strategies to be universally promising for complex transport processes of single or long molecules through biological membranes.

Selecting Erosion- and Deposition-Dominated Zones in the Jezero Delta Using a Water Flow Model for Targeting Future In Situ Mars Surface Missions

Identifying surface sites with significant astrobiological potential on Mars requires a comprehensive understanding of past geological processes and conditions there, including the shallow subsurface region. Numerical modelling could distinguish between regions dominated by erosion and those characterized by sediment accumulation in ancient wet environments. The target area of Jezero Crater is relatively well explored and thus is an ideal site to evaluate model calculations; however, important works are still missing on expectations related to its shallow subsurface . In this work, the best available approaches were followed, and only surface morphology was considered (supposedly formed by the last fluvial episode). The shallow subsurface became an important target recently, and this model could provide new inputs in this area. Erosion–accumulation models are suitable for terrestrial surface features, but few have been applied to Mars. This work addresses this challenge using the SIMWE (SIMulated Water Erosion) model on the Jezero Crater delta, the landing site of the Perseverance rover. For calculations, the average grain size according to the THEMIS TI data was applied to the target area. The flow depth varied between 1.89 and 34.74 m (average of 12.66 m). The water-filled channel width ranged from 35.3 to 341.42 m. A flow velocity of 0.008–11.6 m/s, a maximum erosion rate of 5.98 g/m2/h, and a deposition 4.07 g/m2/h were estimated. These calculated values are close to the range of estimations from other authors assuming precipitation of 1–20 mm/h and discharges of 60–400 m3/s. The model was able to distinguish between erosion- and accumulation-dominated areas about 1 m above Jezero Crater’s delta that are not visible from above. This model helps to identify the accumulation-dominated areas with the finest grain size with good preservation capability for the shallow but invisible subsurface.

How bacteria actively use passive physics to make biofilms

Modern molecular microbiology elucidates the organizational principles of bacterial biofilms via detailed examination of the interplay between signaling and gene regulation. A complementary biophysical approach studies the mesoscopic dependencies at the cellular and multicellular levels with a distinct focus on intercellular forces and mechanical properties of whole biofilms. Here, motivated by recent advances in biofilm research and in other, seemingly unrelated fields of biology and physics, we propose a perspective that links the biofilm, a dynamic multicellular organism, with the physical processes occurring in the extracellular milieu. Using Bacillus subtilis as an illustrative model organism, we specifically demonstrate how such a rationale explains biofilm architecture, differentiation, communication, and stress responses such as desiccation tolerance, metabolism, and physiology across multiple scales—from matrix proteins and polysaccharides to macroscopic wrinkles and water-filled channels.

The antimicrobial fibupeptide lugdunin forms water-filled channel structures in lipid membranes

Recently, a novel cyclo-heptapeptide composed of alternating d,l-amino acids and a unique thiazolidine heterocycle, called lugdunin, was discovered, which is produced by the nasal and skin commensal Staphylococcus lugdunensis. Lugdunin displays potent antimicrobial activity against a broad spectrum of Gram-positive bacteria, including challenging-to-treat methicillin-resistant Staphylococcus aureus (MRSA). Lugdunin specifically inhibits target bacteria by dissipating their membrane potential. However, the precise mode of action of this new class of fibupeptides remains largely elusive. Here, we disclose the mechanism by which lugdunin rapidly destabilizes the bacterial membrane potential using an in vitro approach. The peptide strongly partitions into lipid compositions resembling Gram-positive bacterial membranes but less in those harboring the eukaryotic membrane component cholesterol. Upon insertion, lugdunin forms hydrogen-bonded antiparallel β-sheets by the formation of peptide nanotubes, as demonstrated by ATR-FTIR spectroscopy and molecular dynamics simulations. These hydrophilic nanotubes filled with a water wire facilitate not only the translocation of protons but also of monovalent cations as demonstrated by voltage-clamp experiments on black lipid membranes. Collectively, our results provide evidence that the natural fibupeptide lugdunin acts as a peptidic channel that is spontaneously formed by an intricate stacking mechanism, leading to the dissipation of a bacterial cell’s membrane potential.

Electricity generation from carbon dioxide adsorption by spatially nanoconfined ion separation

Selective ion transport underpins fundamental biological processes for efficient energy conversion and signal propagation. Mimicking these ‘ionics’ in synthetic nanofluidic channels has been increasingly promising for realizing self-sustained systems by harvesting clean energy from diverse environments, such as light, moisture, salinity gradient, etc. Here, we report a spatially nanoconfined ion separation strategy that enables harvesting electricity from CO2 adsorption. This breakthrough relies on the development of Nanosheet-Agarose Hydrogel (NAH) composite-based generators, wherein the oppositely charged ions are released in water-filled hydrogel channels upon adsorbing CO2. By tuning the ion size and ion-channel interactions, the released cations at the hundred-nanometer scale are spatially confined within the hydrogel network, while ångström-scale anions pass through unhindered. This leads to near-perfect anion/cation separation across the generator with a selectivity (D-/D+) of up to 1.8 × 106, allowing conversion into external electricity. With amplification by connecting multiple as-designed generators, the ion separation-induced electricity reaching 5 V is used to power electronic devices. This study introduces an effective spatial nanoconfinement strategy for widely demanded high-precision ion separation, encouraging a carbon-negative technique with simultaneous CO2 adsorption and energy generation.

Self-assembly of water-filled molecular saddles to generate diverse morphologies and high proton conductivity.

The design of single-component organic compounds acting as efficient solid-state proton conduction (SSPC) materials has been gaining significant traction in recent times. Molecular design and controlled self-assembly are critical components in achieving highly efficient SSPC. In this work, we report the design, synthesis, and self-assembly of an organic macrocyclic aza-crown-type compound, P2Mac, which complements synthetic ease with efficient SSPC. P2Mac is derived from the pyridine-2,6-dicarboxamide (PDC) framework and contains polar amide and amine residues in its inner region, while aromatic residues occupy the periphery of the macrocycle. The crystal structure analysis revealed that P2Mac adopts a saddle-shaped geometry. Each P2Mac molecule interacts with one water molecule that is present in its central polar cavity, stabilized by a network of five hydrogen bonds. We could self-assemble P2Mac in a variety of unique, aesthetically pleasing morphologies such as micron-sized octahedra, hexapods, as well as hollow nanoparticles, and microrods. The water-filled polar channels formed through the stacking of P2Mac allow attaining a high proton conductivity value of 21.1 mS cm-1 at 27 °C under a relative humidity (RH) of 95% in the single crystals of P2Mac, while the as-prepared P2Mac pellet sample exhibited about three-orders of magnitude lower conduction under these conditions. The low activation energy of 0.39 eV, calculated from the Arrhenius plot, indicates the presence of the Grotthus proton hopping mechanism in the transport process. This report highlights the pivotal role of molecular design and self-assembly in creating high-performance SSPC organic materials.

Effect of the capillarity and viscosity on the change of flow paths during two-phase displacement in porous media

Pore-scale direct numerical simulations were conducted to explore the changes of flow paths and dynamic distribution of water-oil phases during two-phase displacement in porous media. Three contact angles, i.e., 45°, 90°, and 135°, correspond to water-wet, intermediate-wet, and oil-wet rock surfaces, respectively. The medial axis within complex pore channels is obtained using a grid-based method. Subsequently, a novel particle tracking-based approach is proposed to extract the flow paths during two-phase displacement. The results show that when water enters a porous medium filled with oil, the distribution of oil phase flow paths is uniform, indicating that all oil phases are movable. As water continues to be injected, some water-oil interfaces stop at pores or throats due to capillary force, causing the flow paths through these locations to disappear. In oil-wet and intermediate porous media, capillary forces always act as resistance; therefore, the water-oil interfaces stop at the throat channels. Interestingly, under water-wet conditions, the water-oil interface can reverse, and the capillary force presents resistance, resulting in the interfaces being blocked at enlarging areas, usually from throats to pores. Once breakthrough occurs, preferential flow paths for pure water are established, resulting in a rapid decrease of flow paths with moving water-oil interfaces under oil-wet and intermediate-wet conditions, while movement continues in a water-wet medium. Due to the typically lower viscosity of water than oil, the viscous force decreases as water saturation increases. As water injection continues, the water in some channels gradually displaces oil, resulting in differences in flow rates between oil-filled and water-filled channels. This study provides a method for identifying the changes in flow paths during two-phase displacement in porous media and gives potential benefits for designing strategies to improve oil recovery.

Drug release from PLGA microparticles can be slowed down by a surrounding hydrogel

This study aimed to evaluate and better understand the potential impact that a layer of surrounding hydrogel (mimicking living tissue) can have on the drug release from PLGA microparticles. Ibuprofen-loaded microparticles were prepared with an emulsion solvent extraction/evaporation method. The drug loading was about 48%. The surface of the microparticles appeared initially smooth and non-porous. In contrast, the internal microstructure of the particles exhibited a continuous network of tiny pores. Ibuprofen release from single microparticles was measured into agarose gels and well-agitated phosphate buffer pH 7.4. Optical microscopy, scanning electron microscopy, differential scanning calorimetry, X-ray powder diffraction, and X-ray μCT imaging were used to characterize the microparticles before and after exposure to the release media. Importantly, ibuprofen release was much slower in the presence of a surrounding agarose gel, e.g., the complete release took two weeks vs. a few days in well agitated phosphate buffer. This can probably be attributed to the fact that the hydrogel sterically hinders substantial system swelling and, thus, slows down the related increase in drug mobility. In addition, in this particular case, the convective flow in agitated bulk fluid likely damages the thin PLGA layer at the microparticles' surface, giving the outer aqueous phase more rapid access to the inner continuous pore network: Upon contact with water, the drug dissolves and rapidly diffuses out through a continuous network of water-filled channels. Without direct surface access, most of the drug “has to wait” for the onset of substantial system swelling to be released.

Molecular dynamics simulations of human α-defensin 5 (HD5) crossing gram-negative bacterial membrane.

Human α-defensin 5 (HD5) is a cationic antimicrobial peptide exhibiting a wide range of antimicrobial activities. It plays an important role in mucosal immunity of the small intestine. HD5 exerts its bactericidal activities through multiple mechanisms, one of which involves HD5 inducing the formation of pores in the bacterial membrane, subsequently allowing the peptide to enter the bacterial cytoplasm. Nevertheless, the precise molecular intricacies underlying its bactericidal mechanisms remain inadequately understood. In this work, the Potential of Mean Force (PMF) was computed to delve into the energetic properties governing the movement of HD5 across the lipopolysaccharide (LPS) membrane, which is a representative model of the gram-negative bacterial membrane. Our findings indicate that the most favorable free energy is attained when HD5 binds to the surface of the LPS membrane. This favorable interaction is primarily driven by the strong interactions between arginine residues in HD5 and the charged head groups of LPS, serving as the predominant forces facilitating the adhesion of HD5 to the membrane. Our analysis reveals that a dimeric form of HD5 alone is sufficient to create a water-filled channel in the membrane; however, achieving the complete lysis of the gram-negative bacterial membrane requires higher-order oligomerization of HD5. Our results suggest that HD5 employs the toroidal pore formation mechanism to disrupt the integrity of the LPS membrane. Furthermore, we identified that the primary energy barrier obstructing HD5 from traversing the membrane is localized within the hydrophobic core of the membrane, which is also observed for other defensins. Additionally, our study demonstrates that a mixture of HD5-LPS leads to a thinning of the membrane. Taken together, this work provides a deeper insight into the molecular intricacies governing the behavior of HD5 as it translocates through the gram-negative bacterial membrane.

Temporal and Spatial Evolution Mechanisms of the Water-Conducting Fractured Zone of Overlying Strata in the Kongzhuang Coal Mine

Kongzhuang coal mine of Shanghai Datun Energy Resources Co., Ltd. is a typical deep coal mine in eastern China. The mining disturbance of working face in deep coal mine leads to the fracture and movement of overlying strata and the damage of the aquifer in overlying strata, thereby causing water inrush disaster and posing a serious threat to the safety production in coal mine. Therefore, the temporal and spatial evolution mechanism of the water-conducting fractured zone of overlying strata in the Kongzhuang coal mine is researched systematically in this paper. Especially, the hydro-geological conditions and mining conditions in the Kongzhuang coal mine are analyzed; on this basis, the fracture and movement of overlying strata are simulated by physical similarity simulation test, and the temporal and spatial evolution rule of overlying strata in the Kongzhuang coal mine is obtained. Besides, the development height of “two zones” is measured by double-end water shutoff detection method, and the risk assessment for the water inrush disaster of the coal seam roof is carried out in the Kongzhuang coal mine. The research achievements in this paper indicate that the water-conducting channel formed in the mining process of #7 coal seam is the most important water-filling channel. Quaternary aquifer water recharges the mine indirectly through the bedrock aquifer, and the sandy mudstone with large thickness is the key layer to control the development of a water-conducting fracture zone. Meanwhile, the height of the caving zone is 26.7 m, about 8.3 times of mining height, and the height of the fracture zone is 68.3 m, approximately equal to 16.26 of the mining height. The results of #1 and #2 borehole leakages in the double-end water shutoff detection method show that the height of the water-conducting fractured zone is 63.70 m-65.27 m, and the split-to-mining ratio is 15.17-15.54. The water inrush risk of the coal seam roof shows that most of the 7436 working face is in the transition zone, and a small area around the cutting hole of the working face is in the relatively dangerous zone. Therefore, the innovation of this paper is that the temporal and spatial evolution mechanism of the water-conducting fractured zone of overlying strata in the Kongzhuang coal mine is revealed, which provides the theoretical guidance for the prediction and prevention of water inrush disaster in the coal mine with the similar mining conditions.

Structural basis of mitochondrial protein import by the TIM23 complex.

Mitochondria import nearly all of their approximately 1,000-2,000 constituent proteins from the cytosol across their double-membrane envelope1-5. Genetic and biochemical studies have shown that the conserved protein translocase, termed the TIM23 complex, mediates import of presequence-containing proteins (preproteins) into the mitochondrial matrix and inner membrane. Among about ten different subunits of the TIM23 complex, the essential multipass membrane protein Tim23, together with the evolutionarily related protein Tim17, has long been postulated to form a protein-conducting channel6-11. However, the mechanism by which these subunits form a translocation path in the membrane and enable the import process remains unclear due to a lack of structural information. Here we determined the cryo-electron microscopy structure of the core TIM23 complex (heterotrimeric Tim17-Tim23-Tim44) from Saccharomyces cerevisiae. Contrary to the prevailing model, Tim23 and Tim17 themselves do not form a water-filled channel, but instead have separate, lipid-exposed concave cavities that face in opposite directions. Our structural and biochemical analyses show that the cavity of Tim17, but not Tim23, forms the protein translocation path, whereas Tim23 probably has a structural role. The results further suggest that, during translocation of substrate polypeptides, the nonessential subunit Mgr2 seals the lateral opening of the Tim17 cavity to facilitate the translocation process. We propose a new model for the TIM23-mediated protein import and sorting mechanism, a central pathway in mitochondrial biogenesis.

Numerical study of impact phenomena due to cavitation bubble collapse on metals and polymers

Metals and polymers are the materials most frequently used in hydromachinery components that are prone to cavitation damage. This study examined the damage mechanism of metals (titanium, SUS304, Al2024, and magnesium) and polymers (nylon, Teflon, Adiprene, epoxy, and polyethylene) due to cavitation bubble collapse by utilizing a coupled fluid–solid hydrocodes solver. An air bubble was positioned adjacent to solid material within a long and narrow water-filled channel. A planar shockwave was utilized to create instability within the air bubble, causing a nonspherical collapse that is often observed in cavitation bubbles. By analyzing the wave propagation behavior of bubble collapse impact load (BCIL) acting on the surface, it was revealed that in metals, the impact load is primarily transmitted as elastic waves of compression and shear. Hence, the cavitation damage on metals can be defined by BCIL and acoustic impedance. On the other hand, the BCIL on polymers generates an excessive plastic deformation, so called cavitation pit. An image analysis on cavitation pit growth demonstrated a strong correlation between the pit’s volume and depth with the polymer’s yield strength.

Nearly Reversible Expansion and Shrinkage of Casein Microparticles Triggered by Extreme pH Changes.

Solvent flows in the fL/s range across the total surface of a casein microparticle cause its expansion and shrinkage. Microparticles prepared from the milk protein casein have a porous and flexible inner structure with water-filled channels and cavities. Solvent uptake occurs in two phases and results in disintegration if de-swelling is not triggered by acidification. So far, nothing is known about the reversibility of the swelling/de-swelling steps. We performed pH jump experiments between pH 11 and pH 1 on a single micro-particle and analyzed the swelling-induced size changes with system dynamics modeling. Both the swelling steps and the subsequent de-swelling process proceed reversibly and at an unchanged rate over a sequence of at least three pH exchange cycles. We observed that the duration of the first swelling step increased during the sequence, while the second step became shorter. Both of the time intervals are negatively correlated, while a statistical evaluation of only one swelling cycle for an ensemble of microparticles with different stabilities did not reveal any significant correlation between the two parameters. Our results indicate that the pH-induced swelling/shrinkage of casein microparticles is, to a large extent, reversible and only slightly influenced by the acid-induced decomposition of colloidal calcium phosphate.

Intra-seasonal variability in supraglacial stream sediment on the Greenland Ice Sheet

On the surface of the Greenland Ice Sheet, the presence of low-albedo features greatly contributes to ablation zone meltwater production. Some of the lowest albedo features on the Ice Sheet are water-filled supraglacial stream channels, especially those with abundant deposits of consolidated cryoconite sediment. Because these sediments enhance melting by disproportionately lowering albedo, studying their spatial extent can provide a better understanding of Greenland’s contribution to global sea level rise. However, little is known about the spatial distribution of supraglacial stream sediment, or how it changes in response to seasonal flow regimes. Here, we surveyed a supraglacial stream network in Southwest Greenland, collecting imagery from seven uncrewed aerial vehicle (UAV) flights over the course of 24 days in 2019. Using Structure-from-Motion-generated orthomosaic imagery and digital elevation models (DEMs), we manually digitized the banks of the supraglacial stream channels, classified the areal coverage of sediment deposits, and modeled how the terrain influences the amount of incoming solar radiation at the Ice Sheet surface. We used imagery classified by surface types andin-situspectrometer measurements to determine how changes in sediment cover altered albedo. We found that, within our study area, only 15% of cryoconite sediment was consolidated in cryoconite holes; the remaining 85% was located within supraglacial streams mostly concentrated on daily inundated riverbanks (hereafter termed floodplains). Sediment cover and stream width are highly correlated, suggesting that sediment influx into supraglacial drainage systems widens stream channels or darkens previously widened channels. This reduces albedo in floodplains that already receive greater solar radiation due to their flatness. Additionally, the areal extent of stream sediments increased in August following seasonal peak flow, suggesting that as stream power decreases, more sediment accumulates in supraglacial channels. This negative feedback loop for melting may delay Greenland’s runoff to the latter end of the melt season. This study shows in unprecedented detail where and when sediment is deposited and how these deposits potentially impact the Ice Sheet surface energy balance. These findings may allow for better prediction of how supraglacial floodplains, and the microbiomes they contain, might change in response to increased melting.

Cryo-EM and photocrosslinking studies reveal the mechanism of mitochondrial protein import by the TIM complex.

Mitochondria are essential organelles that provide cells with energy through oxidative phosphorylation, as well as with many important metabolites. Mitochondria import nearly all their ∼1,000-2,000 constituent proteins from the cytosol across their double-membrane envelope. Genetic and biochemical studies have shown that the conserved protein translocase, termed the TIM23 complex, mediates import of presequence-containing precursor proteins (preproteins) into the mitochondrial matrix and inner membrane. However, the mechanism by TIM23 forms a translocation path in the membrane and enables the import process remained unclear. We have determined the cryo-EM structure of the core TIM23 complex (heterotrimeric Tim17-Tim23-Tim44) from Saccharomyces cerevisiae. Contrary to the prevailing model, Tim23 and Tim17 themselves do not form a water-filled channel, but instead have separate, lipid-exposed concave cavities that face in opposite directions. Our structural and biochemical analyses show that surprisingly, the cavity of Tim17, not Tim23, forms the protein translocation path whereas Tim23 is likely to play a structural role. The results further suggest that, during translocation of substrate polypeptides, the nonessential subunit Mgr2 seals the lateral opening of the Tim17 cavity to facilitate the translocation process. We propose a new model for the TIM23-mediated protein import and sorting mechanism, a central pathway in mitochondrial biogenesis.

Nanotubes and water-channels from self-assembling dipeptides.

Dipeptides are attractive building blocks for biomaterials in light of their inherent biocompatibility, biodegradability, and simplicity of preparation. Since the discovery of diphenylalanine (Phe-Phe) self-assembling ability into nanotubes, research efforts have been devoted towards the identification of other dipeptide sequences capable of forming these interesting nanomorphologies, although design rules towards nanotube formation are still elusive. In this review, we analyze the dipeptide sequences reported thus far for their ability to form nanotubes, which often feature water-filled supramolecular channels as revealed by single-crystal X-ray diffraction, as well as their properties, and their potential biological applications, which span from drug delivery and regenerative medicine, to bioelectronics and bioimaging.

Artificial Water Channels—Progress Innovations and Prospects

Artificial Water Channels—Progress Innovations and Prospects

Effects of basal topography and ice-sheet surface slope in a subglacial glaciofluvial deposition model

AbstractWe use a mathematical model to investigate the effect of basal topography and ice surface slope on transport and deposition of sediment within a water-filled subglacial channel. In our model, three zones of different behaviour occur. In the zone furthest upstream, variations in basal topography lead to sediment deposition under a wide range of conditions. In this first zone, even very small and gradually varying basal undulations (~5 m amplitude) can lead to the deposition of sediment within a modelled channel. Deposition is concentrated on the downstream gradient of subglacial ridges, and on the upstream gradient of subglacial troughs. The thickness and steepness of the ice sheet has a substantial impact on deposition rates, with shallow ice profiles strongly promoting both the magnitude and extent of sediment deposition. In a second zone, all sediment is transported downstream. Finally, a third zone close to the ice margin is characterised by high rates of sediment deposition. The existence of these zones has implications for esker formation and the dynamics of the subglacial environment.

Optimised polymer trapped-air lenses for ultrasound focusing in water exploiting Fabry-Pérot resonance

The concept of employing air volumes trapped inside polymer shells to make a lens for ultrasound focusing in water is investigated. The proposed lenses use evenly-spaced concentric rings, each having an air-filled polymer shell construction, defining concentric water-filled channels. Numerical simulations and experiments have shown that a plane wave can be focused, and that the amplification can be boosted by Fabry-Pérot resonances within the water channels with an appropriate choice of the lens thickness. The effect of the polymer shell thickness and the depth of the channels is discussed, as these factors can affect the geometry and hence the frequency of operation. The result was a lens with a Full Width at Half Maximum value of 0.65 of a wavelength at the focus. Results obtained on a metal-based counterpart are also shown for comparison. An advantage of this polymeric design is that it is easily constructed via additive manufacturing. This study shows that trapped-air lenses made of polymer are suitable for ultrasound focusing in water near 500 kHz.

Role of EnvZ/OmpR Two‐component System in Antibiotic Resistance in Salmonella enterica Serovar Enteritidis

Outer membrane porins (OMPs) form water‐filled open channels and allow the entry of small hydrophilic antibiotics. Thus, compositional modulation of OMPs is frequently observed in multidrug‐resistant bacteria, including a human pathogen Salmonella enterica. However, the mechanism by which S. entericamodulates OMP composition to enhance antibiotic resistance has not been well elucidated. In this study, we found that the S. enterica serovar Enteritidis strain with an active state of EnvZ/OmpR is highly resistant to various antibiotics, especially β‐lactams. Transcriptome analysis discovered that the active state of EnvZ/OmpR induces differential expression of multiple OMP genes, including SEN1522, SEN2875, ompD, and ompW. Biochemical analyses identified that OmpR activates SEN1522 and SEN2875 but represses ompD and ompW by directly binding to their upstream regions. Interestingly, the cellular level of OmpR determines the expression of the four OMP genes, and particularly, the phosphorylation of OmpR is not required for the repression of ompD and ompW. Phenotypic analysis revealed that a decreased expression of ompD is responsible for the EnvZ/OmpR‐mediated resistance to β‐lactams in S. Enteritidis. Notably, EnvZ/OmpR represses the expression of ompD upon exposure to β‐lactams and presumably provides S. Enteritidis with benefits for survival. Altogether, this study suggests that EnvZ/OmpR remodels OMP composition in response to β‐lactams and thereby enhances resistance in S. Enteritidis to the antibiotics.