Negative Gaussian Curvature Research Articles

Pattern selection on axial-compressed bilayer systems with a non-zero Gauss curvature

When a soft bilayer system with curved surface is subject to uniaxial compression, surface wrinkles may appear when the compressive strain is beyond a critical value. Interestingly, diverse wrinkling patterns can occur by modulating the feature of the curved surface though the load is simple. Here we study the effect of the sign of Gauss curvature and curvature anisotropy on the wrinkling pattern selection and evolution with experiments, theoretical analysis and numerical simulations. For a system with negative Gauss curvature, our analysis reveals a critical curvature anisotropy below which the critical buckling pattern is a checkerboard mode and will evolve into a diamond-like pattern. Otherwise, the critical buckling mode is sinusoidal. In the post-buckling analysis, our analysis leads to an analytical solution to predict the critical value of the dimensionless curvature that dominates the wrinkling pattern transition. When the dimensionless curvature exceeds such a critical value, the system would branch into the diamond-like mode. Otherwise, the system would maintain the sinusoidal mode. Our results also show that the sign of the Gauss curvature has important influence on critical strain for the onset of wrinkling pattern transition. Negative Gauss curvature promotes the sinusoidal/ diamond-like mode transition, whereas positive Gauss curvature inhibits this wrinkling pattern evaluation. Phase diagrams have been proposed which facilitate the use of the key results achieved in this paper. This study shows an example that a curved system may evolve a surface with complex patterns under simple stimuli by tuning the surface curvature.

Example of Bianchi Transformation of Kuen’s Surface

The work is devoted to the study of the Bianchi transformation for surfaces of constant negative Gaussian curvature. The surfaces of rotation of constant negative Gaussian curvature are the Minding top, the Minding coil, and the pseudosphere (Beltrami surface). Surfaces of constant negative Gaussian curvature also include Kuen’s surface and the Dini’s surface. Studying the surfaces of constant negative Gaussian curvature (pseudospherical surfaces) is of great importance for the interpretation of Lobachevsky planimetry. Geometric characteristics of pseudospherical surfaces are found to be related to the theory of networks, the theory of solitons, nonlinear differential equations, and sin-Gordon equations. The sin-Gordon equation plays an important role in modern physics. Bianchi transformations make it possible to obtain new pseudospherical surfaces from a given pseudospherical surface. The Bianchi transformation for the Kuen’s surface is constructed using a mathematical software package.

Thermoelastic and vibration response analysis of shape memory alloy reinforced active bimorph composites

In this paper, thermoelastic and free vibration responses of hybrid Shape Memory Alloy (SMA) and E-glass fiber-reinforced composites are investigated using finite element analysis. We consider four composites for analysis and comparison of performances, (1) single layer SMA fiber-reinforced hybrid composite (unimorph SMAHC), (2) a two-layer (cross-ply) SMA fiber-reinforced hybrid composite (bimorph SMAHC), (3) single layer SMA fiber-reinforced with a honeycomb core, and (4) single layer SMA fiber-reinforced with reentrant-honeycomb or auxetic core. We analyze the bending response of all the aforementioned composite structures, focusing on the bimorph anticlastic and synclastic bending with negative and positive Gaussian curvatures, respectively. The uniqueness of this work is utilizing the shape memory effect of the SMA fibers to achieve active shape control of low-stiffness and lightweight auxetic composite structures. We investigated the free vibration response and analyzed the effect of the fiber volume fraction and the fiber orientation angle on the natural frequency of the system. Further, the role of the reentrant angle and stiffness of honeycomb struts on the overall effective mechanical properties of the ply is also studied. Results confirm the non-linearity of the parametric combination and the importance of optimization of these parameters for improved Gaussian curvature. The findings are envisaged to be useful for the design of lightweight rigidizable space structures and tensairity structures.

Binary mixtures of bent-core molecules forming distinct types of B4 phase nano- and microfilament morphologies

ABSTRACT The remarkable ability of certain molecules with a bent molecular shape to form hierarchically self-assembled helical building blocks with negative Gaussian or cylindrical curvature featuring in-layer hexatic ordering– so-called B4 phases – has quickly transformed these molecules into desirable building blocks for a variety of potential applications in optics, energy harvesting, and metamaterials. We here demonstrate that these building blocks, helical nanofilaments, helical microfilaments, and heliconical-layered nanocylinders, can to some degree be predictably blended. Supported by scanning as well as transmission electron microscopy and variable angle x-ray scattering data, the three bent-core compounds, each forming exactly one of these B4 morphologies, in binary mixtures at a 1:1 molar ratio, form either the third missing, or one of the two but with opposite handedness, or a random mixture of the two selected morphologies with larger overall dimensions. Furthermore, for two of the mixtures the a priori predicted handedness of the chiral filaments was experimentally confirmed. The third mixture with a priori predicted antagonistic handedness of the initial morphologies forms a combination of the two, one apparently achiral and the other one with opposite handedness.

Pore-scale imaging with measurement of relative permeability and capillary pressure on the same reservoir sandstone sample under water-wet and mixed-wet conditions

Using micro-CT imaging and differential pressure measurements, we design a comparative study in which we simultaneously measure relative permeability and capillary pressure on the same reservoir sandstone sample under water-wet and mixed-wet conditions during steady-state waterflooding experiments. This allows us to isolate the impact of wettability on a pore-by-pore basis and its effect on the macroscopic parameters, capillary pressure and relative permeability, while keeping the pore-space geometry unchanged.First, oil and brine were injected through a water-wet reservoir sandstone sample at a fixed total flow rate, but in a sequence of increasing brine fractional flows with micro-CT scans of the fluid phases taken in each step. Then the sample was brought back to initial water saturation and the surface wettability of the sample was altered after prolonged contact with crude oil and the same measurement procedure was repeated on the altered-wettability sample which we call mixed-wet.Geometric contact angles were measured, which discriminated the water-wet and mixed-wet cases with average values of 75° and 89° respectively. Additionally, an energy balance was used to determine the effective contact angles for displacement which indicated that a higher advancing contact angle of 116° was needed to displace oil in the mixed-wet case. For the water-wet experiment the filling sequence was pore-size dependent, with a strong correlation between pore size and oil occupancy. However, in the mixed-wet experiment the principal determinant of the filling sequence was the wettability rather than the pore size, and there was no correlation between pore size and the residual oil occupancy.The oil-water interfacial area had a larger maximum in the mixed-wet case which was supported by the observation of sheet or saddle-like menisci shapes present throughout the sample volume that impede the flow. These shapes were quantified by much larger negative Gaussian curvature which indicated better connectivity of the phases, consistent with the lower residual oil saturation. Mean curvature and associated capillary pressure were positive for the water-wet case but decreased to a negative value for the mixed-wet case pointing to forced displacement from oil-wet pores. This analysis explained why the relative permeabilities for the mixed-wet case were lower than for the water-wet case for the same fractional flow.

The Effect of Porosity on Elastic Stability of Toroidal Shell Segments Made of Saturated Porous Functionally Graded Materials.

This research deals with the stability analysis of shallow segments of the toroidal shell made of saturated porous functionally graded (FG) material. The nonhomogeneous material properties of porous shell are assumed to be functionally graded as a function of the thickness and porosity parameters. The porous toroidal shell segments with positive and negative Gaussian curvatures and nonuniform distributed porosity are considered. The nonlinear equilibrium equations of the porous shell are derived via the total potential energy of the system. The governing equations are obtained on the basis of classical thin shell theory and the assumptions of Biot's poroelasticity theory. The equations are a set of the coupled partial differential equations. The analytical method including the Airy stress function is used to solve the stability equations of porous shell under mechanical loads in three cases. Porous toroidal shell segments subjected to lateral pressure, axial compression, and hydrostatic pressure loads are analytically analyzed. Closed-form solutions are expressed for the elastic buckling behavior of the convex and concave porous toroidal shell segments. The effects of porosity distribution and geometrical parameters of the shell on the critical buckling loads of porous toroidal shell segments are studied.

Adaptive architecture and mechanoresponse of epithelial cells on a torus

Curvature is a geometric feature widely observed in the epithelia and critical to the performance of fundamental biological functions. Understanding curvature-related biophysical phenomena remains challenging partly owing to the difficulty of quantitatively tuning and measuring curvatures of interfacing individual cells. In this study, we prepared confluent wild-type Madin–Darby canine kidney cells on a torus structure presenting positive, zero, and negative Gaussian curvatures with a tubule diameter of 2–7 cells and quantified the mechanobiological characteristics of individual cells. Cells on the torus surface exhibited topological sensing ability both as an individual cell and collective cell organization. Both cell bodies and nuclei, adapted on the torus, exhibited local Gaussian curvature-dependent preferential orientation. The cells on the torus demonstrated significant adjustment in the nuclear area and exhibited asymmetric nuclear position depending on the local Gaussian curvature. Moreover, cells on top of the torus, where local Gaussian curvature is near zero, exhibited more sensitive morphological adaptations than the nuclei depending on the Gaussian curvature gradient. Furthermore, the spatial heterogeneity of intermediate filament proteins related to mechanoresponsive expression of the cell body and nucleus, vimentin, keratin and lamin A, revealed local Gaussian curvature as a key factor of cellular adaptation on curved surfaces.

Mechanochemical Synthesis of Corannulene-Based Curved Nanographenes.

It is shown that corannulene-based strained π-surfaces can be obtained through the use of mechanochemical Suzuki and Scholl reactions. Besides being solvent-free, the mechanochemical synthesis is high-yielding, fast, and scalable. Therefore, gram-scale preparation can be carried out in a facile and sustainable manner. The synthesized nanographene structure carries positive (bowl-like) and negative (saddle-like) Gaussian curvatures and adopts an overall quasi-monkey saddle-type of geometry. In terms of properties, the non-planar surface exhibits a high electron affinity that was measured by cyclic voltammetry, with electrolysis and in situ UV/vis spectroscopy experiments indicating that the one-electron reduced state displays a long lifetime in solution. Overall, these results indicate the future potential of mechanochemistry in accessing synthetically challenging and functional curved π-systems.

Mechanochemical Synthesis of Corannulene‐Based Curved Nanographenes

AbstractIt is shown that corannulene‐based strained π‐surfaces can be obtained through the use of mechanochemical Suzuki and Scholl reactions. Besides being solvent‐free, the mechanochemical synthesis is high‐yielding, fast, and scalable. Therefore, gram‐scale preparation can be carried out in a facile and sustainable manner. The synthesized nanographene structure carries positive (bowl‐like) and negative (saddle‐like) Gaussian curvatures and adopts an overall quasi‐monkey saddle‐type of geometry. In terms of properties, the non‐planar surface exhibits a high electron affinity that was measured by cyclic voltammetry, with electrolysis and in situ UV/vis spectroscopy experiments indicating that the one‐electron reduced state displays a long lifetime in solution. Overall, these results indicate the future potential of mechanochemistry in accessing synthetically challenging and functional curved π‐systems.

Discovery of Novel Type II Bacteriocins Using a New High-Dimensional Bioinformatic Algorithm.

Antimicrobial compounds first arose in prokaryotes by necessity for competitive self-defense. In this light, prokaryotes invented the first host defense peptides. Among the most well-characterized of these peptides are class II bacteriocins, ribosomally-synthesized polypeptides produced chiefly by Gram-positive bacteria. In the current study, a tensor search protocol—the BACIIα algorithm—was created to identify and classify bacteriocin sequences with high fidelity. The BACIIα algorithm integrates a consensus signature sequence, physicochemical and genomic pattern elements within a high-dimensional query tool to select for bacteriocin-like peptides. It accurately retrieved and distinguished virtually all families of known class II bacteriocins, with an 86% specificity. Further, the algorithm retrieved a large set of unforeseen, putative bacteriocin peptide sequences. A recently-developed machine-learning classifier predicted the vast majority of retrieved sequences to induce negative Gaussian curvature in target membranes, a hallmark of antimicrobial activity. Prototypic bacteriocin candidate sequences were synthesized and demonstrated potent antimicrobial efficacy in vitro against a broad spectrum of human pathogens. Therefore, the BACIIα algorithm expands the scope of prokaryotic host defense bacteriocins and enables an innovative bioinformatics discovery strategy. Understanding how prokaryotes have protected themselves against microbial threats over eons of time holds promise to discover novel anti-infective strategies to meet the challenge of modern antibiotic resistance.

Results on equality of masses for choreographic solutions of n-body problems

We prove that equally spaced choreographic solutions of a large class of n-body problems, including the classical n-body problem and a subset of quasi-homogeneous n-body problems, have equal masses if the dimension of the space spanned by the point masses is n − 1, n − 2, or, if n is odd, if the dimension is n − 3. If n is even and the dimension is n − 3, then all masses with an odd label are equal and all masses with an even label are equal. Additionally, we prove that the same results hold true for any solution of an n + 1-body problem for which n of the point masses behave like an equally spaced choreography and the n + 1th point mass is fixed at the origin. Furthermore, we deduce that if the curve along which the point masses of a choreography move has an axis of symmetry, the masses have to be equal if n = 3 and that if n = 4, if three of the point masses behave as stated and the fourth mass is fixed at a point, the masses of the first three point masses are all equal. Finally, we prove for the n-body problem in spaces of negative constant Gaussian curvature that if n < 6, n ≠ 4, equally spaced choreographic solutions should have equal masses, and for n = 4, the even labeled masses are equal and the odd labeled masses are equal and that the same holds true for the n-body problem in spaces of positive constant Gaussian curvature, as long as the point masses do not move along a great circle. Additionally, we show that these last two results are also true for any solution to the n + 1-body problem in spaces of negative constant Gaussian curvature and the n + 1-body problem in spaces of positive constant Gaussian curvature, respectively, for the case that n of the point masses behave like an equally spaced choreography and the n + 1 is fixed at a point.

Determination of the Configurations of Boundaries in Space

AbstractThis research aims to determine the geometrical configurations of boundary surfaces in the space environment, based on multiple spacecraft measurements. To achieve this, the Normal Field Analysis (NFA) method is presented here. With multipoint observations, the three‐dimensional gradient of the normal of boundary layers can be obtained, and the principal curvatures and principal directions of the surfaces can be deduced. The correctness of the method is then verified. Two initial applications have been carried out. The first is to determine the geometrical features of the Earth's bow shock where it is found that, with a one‐dimensional approximation, the surface of the bow shock has a rotational conicoid shape with eccentricity about 0.82, consistent with previous studies. Second, the method is also used to analyze two magnetotail dipolarization fronts showing that the dipolarization fronts are hyperbolic paraboloids or saddle surfaces with negative Gaussian curvatures. The south‐north scale of the dipolarization fronts is about 0.835–3.98 RE, and the dawn‐dusk/azimuthal scale is about 1.58–1.92 RE, confirming previous studies. The method presented can also be applied to investigate the geometries of the magnetopause, plasmapause, and other boundaries.

Dynamics of water injection in an oil-wet reservoir rock at subsurface conditions: Invasion patterns and pore-filling events.

We use fast synchrotron x-ray microtomography to investigate the pore-scale dynamics of water injection in an oil-wet carbonate reservoir rock at subsurface conditions. We measure, in situ, the geometric contact angles to confirm the oil-wet nature of the rock and define the displacement contact angles using an energy-balance-based approach. We observe that the displacement of oil by water is a drainagelike process, where water advances as a connected front displacing oil in the center of the pores, confining the oil to wetting layers. The displacement is an invasion percolation process, where throats, the restrictions between pores, fill in order of size, with the largest available throats filled first. In our heterogeneous carbonate rock, the displacement is predominantly size controlled; wettability has a smaller effect, due to the wide range of pore and throat sizes, as well as largely oil-wet surfaces. Wettability only has an impact early in the displacement, where the less oil-wet pores fill by water first. We observe drainage associated pore-filling dynamics including Haines jumps and snap-off events. Haines jumps occur on single- and/or multiple-pore levels accompanied by the rearrangement of water in the pore space to allow the rapid filling. Snap-off events are observed both locally and distally and the capillary pressure of the trapped water ganglia is shown to reach a new capillary equilibrium state. We measure the curvature of the oil-water interface. We find that the total curvature, the sum of the curvatures in orthogonal directions, is negative, giving a negative capillary pressure, consistent with oil-wet conditions, where displacement occurs as the water pressure exceeds that of the oil. However, the product of the principal curvatures, the Gaussian curvature, is generally negative, meaning that water bulges into oil in one direction, while oil bulges into water in the other. A negative Gaussian curvature provides a topological quantification of the good connectivity of the phases throughout the displacement.

Flattening Effect of Negative Gaussian Curvature on Simply Supported Thick Asymmetric Cross-Ply Panels in the Absence of Surface-Parallel Edge Restraints

AbstractThis paper investigated the flattening effect of negative Gaussian curvature on simply supported (SS) thick asymmetrically laminated cross-ply panels in the absence of surface-parallel edge...

Creation of negatively curved polyaromatics enabled by annulative coupling that forms an eight-membered ring

The discoveries of new forms of carbon have always opened doors to new science and technology. In 1991, three-dimensional (3D) periodic carbon crystals with negative Gaussian curvatures that consist of six- and eight-membered rings were proposed. To realize these 3D periodic carbon crystals (known as Mackay crystals), methods for creating polyaromatic structures embedding eight-membered rings must be developed. Here we report two annulative coupling reactions that form an eight-membered ring through catalytic C–H functionalization. We have discovered that bay-chlorinated polyaromatics undergo either annulative dimerization or cross-coupling with biphenylene in the presence of a palladium catalyst to form various hitherto inaccessible polyaromatics embedding an eight-membered ring. The threefold annulative cross-coupling of 1,5,9-trichlorotriphenylene allowed construction of a highly curved nanocarbon. The present work not only demonstrates the potential of annulative coupling for constructing octagonal nanocarbons but also provides a conceptual pathway for the synthetic realization of 3D periodic carbon crystals. The Mackay crystal is a proposed—but synthetically unachieved—nanocarbon molecule that is anticipated to have many desirable properties. Now, a strategy based on annulative coupling of chlorophenanthrene derivatives is reported, allowing streamlined access to an important substructure.

The Asymptotically Sharp Geometric Rigidity Interpolation Estimate in Thin Bi-Lipschitz Domains

This work is part of a program of development of asymptotically sharp geometric rigidity estimates for thin domains. A thin domain in three dimensional Euclidean space is roughly a small neighborhood of regular enough two dimensional compact surface. We prove an asymptotically sharp geometric rigidity interpolation inequality for thin domains with little regularity. In contrast to that celebrated Friesecke et al. rigidity estimate [Commun. Pure Appl. Math. 55(11):1461–1506, 2002] for plates, our estimate holds for any proper rotations $\boldsymbol {R}\in SO(3)$ . Namely, the estimate bounds the $L^{p}$ distance of the gradient of any $\boldsymbol {y}\in W^{1,p}(\Omega ,\mathbb{R}^{3})$ field from any constant proper rotation $\boldsymbol {R}\in SO(3)$ , in terms of the average $L^{p}$ distance (nonlinear strain) of the gradient $\nabla \boldsymbol {y}$ from the rotation group $SO(3)$ , and the average $L^{p}$ distance of the field itself from the set of rigid motions corresponding to the rotation $\boldsymbol {R}$ . There are several remarkable facts about the estimate: 1. The constants in the estimate are sharp in terms of the domain thickness scaling for any thin domains with the required regularity. 2. In the special cases when the domain has positive or negative Gaussian curvature, the inequality reduces the problem of estimating the gradient $\nabla \boldsymbol {y}$ in terms of the prototypical nonlinear strain $\int _{\Omega }\mathrm{dist}^{p}(\nabla \boldsymbol {y}(x),SO(3))dx$ to the easier problem of estimating only the vector field $\boldsymbol {y}$ in terms of the nonlinear strain without any loss in the constant scalings as the Ansatze suggest. The later will be a geometric rigidity Korn-Poincare type estimate. This passage is major progress in the thin domain rigidity problem. 3. For the borderline energy scaling (bending-to-stretching), the estimate implies improved strong compactness on the vector fields for free. Finally, this being said, our new interpolation inequality reduces the problem of proving “any” geometric one well rigidity problem in thin domains to estimating the vector field itself instead of the gradient, thus reducing the complexity of the problem.

Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation

Endosomal sorting complexes for transport-III (ESCRT-III) assemble in vivo onto membranes with negative Gaussian curvature. How membrane shape influences ESCRT-III polymerization and how ESCRT-III shapes membranes is yet unclear. Human core ESCRT-III proteins, CHMP4B, CHMP2A, CHMP2B and CHMP3 are used to address this issue in vitro by combining membrane nanotube pulling experiments, cryo-electron tomography and AFM. We show that CHMP4B filaments preferentially bind to flat membranes or to tubes with positive mean curvature. Both CHMP2B and CHMP2A/CHMP3 assemble on positively curved membrane tubes. Combinations of CHMP4B/CHMP2B and CHMP4B/CHMP2A/CHMP3 are recruited to the neck of pulled membrane tubes and reshape vesicles into helical “corkscrew-like” membrane tubes. Sub-tomogram averaging reveals that the ESCRT-III filaments assemble parallel and locally perpendicular to the tube axis, highlighting the mechanical stresses imposed by ESCRT-III. Our results underline the versatile membrane remodeling activity of ESCRT-III that may be a general feature required for cellular membrane remodeling processes.

Topological transitions in the configuration space of non-Euclidean origami.

Origami structures have been proposed as a means of creating three-dimensional structures from the micro- to the macroscale and as a means of fabricating mechanical metamaterials. The design of such structures requires a deep understanding of the kinematics of origami fold patterns. Here we study the configurations of non-Euclidean origami, folding structures with Gaussian curvature concentrated on the vertices, for arbitrary origami fold patterns. The kinematics of such structures depends crucially on the sign of the Gaussian curvature. As an application of our general results, we show that the configuration space of nonintersecting, oriented vertices with positive Gaussian curvature decomposes into disconnected subspaces; there is no pathway between them without tearing the origami. In contrast, the configuration space of negative Gaussian curvature vertices remains connected. This provides a new, and only partially explored, mechanism by which the mechanics and folding of an origami structure could be controlled.

How do cyclic antibiotics with activity against Gram-negative bacteria permeate membranes? A machine learning informed experimental study

All antibiotics have to engage bacterial amphiphilic barriers such as the lipopolysaccharide-rich outer membrane or the phospholipid-based inner membrane in some manner, either by disrupting them outright and/or permeating them and thereby allow the antibiotic to get into bacteria. There is a growing class of cyclic antibiotics, many of which are of bacterial origin, that exhibit activity against Gram-negative bacteria, which constitute an urgent problem in human health. We examine a diverse collection of these cyclic antibiotics, both natural and synthetic, which include bactenecin, polymyxin B, octapeptin, capreomycin, and Kirshenbaum peptoids, in order to identify what they have in common when they interact with bacterial lipid membranes. We find that they virtually all have the ability to induce negative Gaussian curvature (NGC) in bacterial membranes, the type of curvature geometrically required for permeation mechanisms such as pore formation, blebbing, and budding. This is interesting since permeation of membranes is a function usually ascribed to antimicrobial peptides (AMPs) from innate immunity. As prototypical test cases of cyclic antibiotics, we analyzed amino acid sequences of bactenecin, polymyxin B, and capreomycin using our recently developed machine-learning classifier trained on α-helical AMP sequences. Although the original classifier was not trained on cyclic antibiotics, a modified classifier approach correctly predicted that bactenecin and polymyxin B have the ability to induce NGC in membranes, while capreomycin does not. Moreover, the classifier was able to recapitulate empirical structure–activity relationships from alanine scans in polymyxin B surprisingly well. These results suggest that there exists some common ground in the sequence design of hybrid cyclic antibiotics and linear AMPs.

Switchable Membrane Remodeling and Antifungal Defense by Metamorphic Chemokine XCL1.

Antimicrobial peptides (AMPs) are a class of molecules which generally kill pathogens via preferential cell membrane disruption. Chemokines are a family of signaling proteins that direct immune cell migration and share a conserved α–β tertiary structure. Recently, it was found that a subset of chemokines can also function as AMPs, including CCL20, CXCL4, and XCL1. It is therefore surprising that machine learning based analysis predicts that CCL20 and CXCL4’s α-helices are membrane disruptive, while XCL1’s helix is not. XCL1, however, is the only chemokine known to be a metamorphic protein which can interconvert reversibly between two distinct native structures (a β-sheet dimer and the α–β chemokine structure). Here, we investigate XCL1’s antimicrobial mechanism of action with a focus on the role of metamorphic folding. We demonstrate that XCL1 is a molecular “Swiss army knife” that can refold into different structures for distinct context-dependent functions: whereas the α–β chemokine structure controls cell migration by binding to G-Protein Coupled Receptors (GPCRs), we find using small angle X-ray scattering (SAXS) that only the β-sheet and unfolded XCL1 structures can induce negative Gaussian curvature (NGC) in membranes, the type of curvature topologically required for membrane permeation. Moreover, the membrane remodeling activity of XCL1’s β-sheet structure is strongly dependent on membrane composition: XCL1 selectively remodels bacterial model membranes but not mammalian model membranes. Interestingly, XCL1 also permeates fungal model membranes and exhibits anti-Candida activity in vitro, in contrast to the usual mode of antifungal defense which requires Th17 mediated cell-based responses. These observations suggest that metamorphic XCL1 is capable of a versatile multimodal form of antimicrobial defense.