Mechanisms Of Compartmentalization Research Articles

Interaction-Dependent Secondary Structure of Peptides in Biomolecular Condensates.

Biomolecular condensates provide a mechanism for compartmentalization of biomolecules in eukaryotic cells. These liquid-like condensates are formed via liquid-liquid phase separation, by a plethora of interactions, and can mediate several biological processes in healthy cells. Expansions of dipeptide repeat proteins, DPRs, in which arginine rich DPRs like poly-proline-arginine (PR), and poly-glycine-arginine (GR), partition RNA into condensates can however induce cell toxicity. Here, we use (GR)20 as a model for biological poly-GR and condense it using either excluded volume interactions with polyethylene glycol (PEG) as a crowder or direct electrostatic interactions with RNA oligomers. Using two-dimensional infrared (2D IR) spectroscopy, we observe that (GR)20 condensed through an excluded volume forms β-sheet structures, whereas (GR)20 condensed with RNA forms loops. We also investigate local hydrogen-bond dynamics in the condensate and compare the measurements with molecular dynamics simulations. Hydrogen bond lifetimes undergo a marked slowdown compared to dynamics in the dilute phase. This is representative of confined water within the percolated networks inside the condensate due to the interaction present in the condensate disrupting H-bond networks. Overall, our results show that both protein structure and dynamics are inherently dependent on the type of interactions that stabilize the condensates.

Tissue-Specific Regulation of Vesicular Trafficking Mediated by Rab-GEF Complex MON1/CCZ1 From Solanum chilense Increases Salt Stress Tolerance in Arabidopsis thaliana.

Salt stress constrains the development and growth of plants. To tolerate it, mechanisms of endocytosis and vacuolar compartmentalization of Na+ are induced. In this work, the genes that encode a putative activator of vesicular trafficking called MON1/CCZ1 from Solanum chilense, SchMON1 and SchCCZ1, were co-expressed in roots of Arabidopsis thaliana to determine whether the increase in prevacuolar vesicular trafficking also increases the Na+ compartmentalization capacity and tolerance. Initially, we demonstrated that both SchMON1 and SchCCZ1 genes rescued the dwarf phenotype of both A. thaliana mon1-1 and ccz1a/b mutants associated with the loss of function, and both proteins colocalized with their functional targets, RabF and RabG, in endosomes. Transgenic A. thaliana plants co-expressing these genes improved salt stress tolerance compared to wild type plants, with SchMON1 contributing the most. At the sub-cellular level, co-expression of SchMON1/SchCCZ1 reduced ROS levels and increased endocytic activity, and number of acidic structures associated with autophagosomes. Notably, greater Na+ accumulation in vacuoles of cortex and endodermis was evidenced in the SchMON1 genotype. Molecular analysis of gene expression in each genotype supported these results. Altogether, our analysis shows that root activation of prevacuolar vesicular trafficking mediated by MON1/CCZ1 emerges as a promising physiological molecular mechanism to increase tolerance to salt stress in crops of economic interest.

Hybrid Protocells Based on Coacervate-Templated Fatty Acid Vesicles Combine Improved Membrane Stability with Functional Interior Protocytoplasm.

Prebiotically-plausible compartmentalization mechanisms include membrane vesicles formed by amphiphile self-assembly and coacervate droplets formed by liquid-liquid phase separation. Both types of structures form spontaneously and can be related to cellular compartmentalization motifs in today's living cells. As prebiotic compartments, they have complementary capabilities, with coacervates offering excellent solute accumulation and membranes providing superior boundaries. Herein, protocell models constructed by spontaneous encapsulation of coacervate droplets by mixed fatty acid/phospholipid and by purely fatty acid membranes are described. Coacervate-supported membranes form over a range of coacervate and lipid compositions, with membrane properties impacted by charge-charge interactions between coacervates and membranes. Vesicles formed by coacervate-templated membrane assembly exhibit profoundly different permeability than traditional fatty acid or blended fatty acid/phospholipid membranes without a coacervate interior, particularly in the presence of magnesium ions (Mg2+). While fatty acid and blended membrane vesicles are disrupted by the addition of Mg2+, the corresponding coacervate-supported membranes remain intact and impermeable to externally-added solutes. With the more robust membrane, fluorescein diacetate (FDA) hydrolysis, which is commonly used for cell viability assays, can be performed inside the protocell model due to the simple diffusion of FDA and then following with the coacervate-mediated abiotic hydrolysis to fluorescein.

Postmortem Analysis of Dolutegravir, Tenofovir, Lamivudine, and Efavirenz Penetration in Multiple Central Nervous System Compartments.

Central nervous system (CNS) compartmentalization provides opportunity for human immunodeficiency virus (HIV) persistence and resistance development. Differences between cerebrospinal fluid (CSF) and cerebral matter regarding HIV persistence are well described. However, CSF is often used as surrogate for CNS drug exposure, and knowledge from solid brain tissue is rare. Dolutegravir, tenofovir, lamivudine, and efavirenz concentrations were measured across 13 CNS regions plus plasma in samples collected during autopsy in 49 Ugandan decedents. Median time from death to autopsy was 8 hours (interquartile range, 5-15 hours). To evaluate postmortem redistribution, a time course study was performed in a mouse model. Regions with the highest penetration ratios were choroid plexus/arachnoid (dolutegravir and tenofovir), CSF (lamivudine), and cervical spinal cord/meninges (efavirenz); the lowest were corpus callosum (dolutegravir and tenofovir), frontal lobe (lamivudine), and parietal lobe (efavirenz). On average, brain concentrations were 84%, 87%, and 76% of CSF for dolutegravir, tenofovir, and lamivudine, respectively. Postmortem redistribution was observed in the mouse model, with tenofovir and lamivudine concentration increased by 350% and efavirenz concentration decreased by 24% at 24 hours postmortem. Analysis of postmortem tissue provides a unique opportunity to investigate CNS antiretroviral penetration. Regional differences were observed paving the way to identify mechanisms of viral compartmentalization and/or neurotoxicity.

Diffusive lensing as a mechanism of intracellular transport and compartmentalization.

While inhomogeneous diffusivity has been identified as a ubiquitous feature of the cellular interior, its implications for particle mobility and concentration at different length scales remain largely unexplored. In this work, we use agent-based simulations of diffusion to investigate how heterogeneous diffusivity affects the movement and concentration of diffusing particles. We propose that a nonequilibrium mode of membrane-less compartmentalization arising from the convergence of diffusive trajectories into low-diffusive sinks, which we call 'diffusive lensing,' is relevant for living systems. Our work highlights the phenomenon of diffusive lensing as a potentially key driver of mesoscale dynamics in the cytoplasm, with possible far-reaching implications for biochemical processes.

Diffusive lensing as a mechanism of intracellular transport and compartmentalization

While inhomogeneous diffusivity has been identified as a ubiquitous feature of the cellular interior, its implications for particle mobility and concentration at different length scales remain largely unexplored. In this work, we use agent-based simulations of diffusion to investigate how heterogeneous diffusivity affects the movement and concentration of diffusing particles. We propose that a nonequilibrium mode of membrane-less compartmentalization arising from the convergence of diffusive trajectories into low-diffusive sinks, which we call ‘diffusive lensing,’ is relevant for living systems. Our work highlights the phenomenon of diffusive lensing as a potentially key driver of mesoscale dynamics in the cytoplasm, with possible far-reaching implications for biochemical processes.

Dopamine-mediated autocrine inhibition of insulin secretion

The aim of the present research was to explore the mechanisms underlying the role of dopamine in the regulation of insulin secretion in beta cells. The effect of dopamine on insulin secretion was investigated on INS 832/13 cell line upon glucose and other secretagogues stimulation. Results show that dopamine significantly inhibits insulin secretion stimulated by both glucose and other secretagogues, while it has no effect on the basal secretion. This effect requires the presence of dopamine during incubation with the various secretagogues. Both electron microscopy and immunohistochemistry indicate that in beta cells the D2 dopamine receptor is localized within the insulin granules. Blocking dopamine entry into the insulin granules by inhibiting the VMAT2 transporter with tetrabenazine causes a significant increase in ROS production. Our results confirm that dopamine plays an important role in the regulation of insulin secretion by pancreatic beta cells through a regulated and precise compartmentalization mechanisms.

Exploring the Subcellular Localization of Monascus Pigments Biosynthases: Preliminary Unraveling of the Compartmentalization Mechanism.

Monascus pigments (MPs), a class of secondary metabolites produced by Monascus spp., can be classified into yellow, orange, and red MPs according to their differences in the wavelength of the maximum absorption. However, the biosynthetic sequence and cellular biosynthesis mechanism of different MPs components are still not yet completely clear in Monascus spp. In this study, the subcellular localization of five MPs synthases was investigated using fluorescent protein fusion expression. The results revealed that the proteins encoded by the MPs biosynthetic gene cluster were compartmentalized in various subcellular locations, including the mitochondrial polyketide synthase MrPigA, cytosolic enzymes consisting of the ketoreductase MrPigC, the oxidoreductase MrPigE, and the monooxygenase MrPigN, and the cell-wall-bound oxidoreductase MrPigF. Moreover, the correct localization of MrPigF to the cell wall was crucial for the synthesis of orange MPs. Lastly, we discussed the compartmentalized biosynthetic pathway of MPs. This study will not only be helpful in clarifying the biosynthetic sequence and biosynthesis mechanism of different MPs but also provides new insights into the cellular biosynthesis of secondary metabolites in filamentous fungi.

Thermodynamic modulation of gephyrin condensation by inhibitory synapse components

Phase separation drives compartmentalization of intracellular contents into various biomolecular condensates. Individual condensate components are thought to differentially contribute to the organization and function of condensates. However, how intermolecular interactions among constituent biomolecules modulate the phase behaviors of multicomponent condensates remains unclear. Here, we used core components of the inhibitory postsynaptic density (iPSD) as a model system to quantitatively probe how the network of intra- and intermolecular interactions defines the composition and cellular distribution of biomolecular condensates. We found that oligomerization-driven phase separation of gephyrin, an iPSD-specific scaffold, is critically modulated by an intrinsically disordered linker region exhibiting minimal homotypic attractions. Other iPSD components, such as neurotransmitter receptors, differentially promote gephyrin condensation through distinct binding modes and affinities. We further demonstrated that the local accumulation of scaffold-binding proteins at the cell membrane promotes the nucleation of gephyrin condensates in neurons. These results suggest that in multicomponent systems, the extent of scaffold condensation can be fine-tuned by scaffold-binding factors, a potential regulatory mechanism for self-organized compartmentalization in cells.

Expression analysis of genes encoding salt induced transport proteins in two contrasting rice cultivars with different salt stress tolerance

Soil salinization is a serious global problem that impedes the growth and development of numerous agricultural crops worldwide. Plants have evolved a diversity of adaptive mechanisms for coping with salt stress. Among the known mechanisms, the ability of plants to maintain intracellular ions and osmotic homeostasis via exclusion and compartmentalization of salt is highly correlated with high salt stress tolerance. Several transport proteins, such as high-affinity K+ transporter 1 (HKT1), high affinity K+/Na+ transporter 10 (HAK10), salt overly sensitive 1 (SOS1), and sodium/hydrogen exchanger 1 (NHX1), have been identified to be associated with the exclusion and compartmentalization of salt. In this study, an investigation was conducted to evaluate the expression of genes encoding SOS1, HKT1, HAK10, and NHX1 transporters in the leaf and root tissues of two contrasting rice cultivars, salt tolerant DP and salt sensitive IR28, under salt stress of 150 mM NaCl by RT-qPCR approach. RT-qPCR data revealed that the expression of HKT1, HAK10, SOS1, and NXH1 were upregulated at a higher level in the DP cultivar than in the IR28 cultivar in response to salt stress treatment. Our findings also suggest that the DP rice cultivar acquires a higher level of salt tolerance than the IR28 cultivar, at least a part due to a greater degree of Na+ exclusion and compartmentalization mechanisms provided by HKT1, HAK10, SOS1, and NXH1 transporters.

Efficient Hi-C inversion facilitates chromatin folding mechanism discovery and structure prediction

Genome-wide chromosome conformation capture (Hi-C) experiments have revealed many structural features of chromatin across multiple length scales. Further understanding genome organization requires relating these discoveries to the mechanisms that establish chromatin structures and reconstructing these structures in three dimensions, but both objectives are difficult to achieve with existing algorithms that are often computationally expensive. To alleviate this challenge, we present an algorithm that efficiently converts Hi-C data into contact energies, which measure the interaction strength between genomic loci brought into proximity. Contact energies are local quantities unaffected by the topological constraints that correlate Hi-C contact probabilities. Thus, extracting contact energies from Hi-C contact probabilities distills the biologically unique information contained in the data. We show that contact energies reveal the location of chromatin loop anchors, support a phase separation mechanism for genome compartmentalization, and parameterize polymer simulations that predict three-dimensional chromatin structures. Therefore, we anticipate that contact energy extraction will unleash the full potential of Hi-C data and that our inversion algorithm will facilitate the widespread adoption of contact energy analysis.

Biomolecular phase separation in stress granule assembly and virus infection.

Liquid-liquid phase separation (LLPS) has emerged as a crucial mechanism for cellular compartmentalization. One prominent example of this is the stress granule. Found in various types of cells, stress granule is a biomolecular condensate formed through phase separation. It comprises numerous RNA and RNA-binding proteins. Over the past decades, substantial knowledge has been gained about the composition and dynamics of stress granules. SGs can regulate various signaling pathways and have been associated with numerous human diseases, such as neurodegenerative diseases, cancer, and infectious diseases. The threat of viral infections continues to loom over society. Both DNA and RNA viruses depend on host cells for replication. Intriguingly, many stages of the viral life cycle are closely tied to RNA metabolism in human cells. The field of biomolecular condensates has rapidly advanced in recent times. In this context, we aim to summarize research on stress granules and their link to viral infections. Notably, stress granules triggered by viral infections behave differently from the canonical stress granules triggered by sodium arsenite (SA) and heat shock. Studying stress granules in the context of viral infections could offer a valuable platform to link viral replication processes and host anti-viral responses. A deeper understanding of these biological processes could pave the way for innovative interventions and treatments for viral infectious diseases. They could potentially bridge the gap between basic biological processes and interactions between viruses and their hosts.

Unravelling the colonization mechanism of Lasiodiplodia brasiliensis in grapevine plants

Botryosphaeriaceae cause the degenerative disease Botryosphaeria dieback in many woody hosts, including grapevine. These pathogens penetrate host plants through pruning wounds, and colonize vascular tissues causing necrotic lesions, cankers, and eventually plant death. Colonization processes by Botryosphaeriaceae and their interactions with their hosts has been understudied. The colonization mechanisms were examined for Lasiodiplodia brasiliensis, a common pathogen causing Botryosphaeria dieback in Mexican vineyards. Lasiodiplodia brasiliensis MXBCL28 was inoculated onto grapevine ‘Cabernet Sauvignon’ plants, and after 2 months, infected tissues were observed with microscopy using histological techniques. Lasiodiplodia brasiliensis was also cultured on different carbon sources representing cell walls and non-structural plant components, to complement histology data. The host responded to wounding by developing xylem vessel occlusions with tyloses and deposition of suberin in cambium and ray parenchyma. Infection response also included deposition of suberin in pith tissues, reinforcement of cell walls with phenolic compounds, and lignin deposition in xylem vessels and ray parenchyma. The pathogen could overcome host compartmentalization mechanisms and colonize wood tissue causing extensive necrosis. The fungus was visualized in host cambium, vascular bundles, xylem vessels, and pith, and infected tissues were depleted in starch in the ray parenchyma. Cellulose, hemicellulose, and lignin in cell walls were also degraded, supporting in vitro data.

Region Capture Micro-C reveals coalescence of enhancers and promoters into nested microcompartments.

Although enhancers are central regulators of mammalian gene expression, the mechanisms underlying enhancer-promoter (E-P) interactions remain unclear. Chromosome conformation capture (3C) methods effectively capture large-scale three-dimensional (3D) genome structure but struggle to achieve the depth necessary to resolve fine-scale E-P interactions. Here, we develop Region Capture Micro-C (RCMC) by combining micrococcal nuclease (MNase)-based 3C with a tiling region-capture approach and generate the deepest 3D genome maps reported with only modest sequencing. By applying RCMC in mouse embryonic stem cells and reaching the genome-wide equivalent of ~317 billion unique contacts, RCMC reveals previously unresolvable patterns of highly nested and focal 3D interactions, which we term microcompartments. Microcompartments frequently connect enhancers and promoters, and although loss of loop extrusion and inhibition of transcription disrupts some microcompartments, most are largely unaffected. We therefore propose that many E-P interactions form through a compartmentalization mechanism, which may partially explain why acute cohesin depletion only modestly affects global gene expression.

Membraneless Compartmentalization of Nuclear Assembly Sites during Murine Cytomegalovirus Infection.

Extensive reorganization of infected cells and the formation of large structures known as the nuclear replication compartment (RC) and cytoplasmic assembly compartment (AC) is a hallmark of beta-herpesvirus infection. These restructurings rely on extensive compartmentalization of the processes that make up the virus manufacturing chain. Compartmentalization of the nuclear processes during murine cytomegalovirus (MCMV) infection is not well described. In this study, we visualized five viral proteins (pIE1, pE1, pM25, pm48.2, and pM57) and replicated viral DNA to reveal the nuclear events during MCMV infection. As expected, these events can be matched with those described for other beta and alpha herpesviruses and contribute to the overall picture of herpesvirus assembly. Imaging showed that four viral proteins (pE1, pM25, pm48.2, and pM57) and replicated viral DNA condense in the nucleus into membraneless assemblies (MLAs) that undergo a maturation sequence to form the RC. One of these proteins (pM25), which is also expressed in a cytoplasmic form (pM25l), showed similar MLAs in the AC. Bioinformatics tools for predicting biomolecular condensates showed that four of the five proteins had a high propensity for liquid-liquid phase separation (LLPS), suggesting that LLPS may be a mechanism for compartmentalization within RC and AC. Examination of the physical properties of MLAs formed during the early phase of infection by 1,6-hexanediol treatment in vivo revealed liquid-like properties of pE1 MLAs and more solid-like properties of pM25 MLAs, indicating heterogeneity of mechanisms in the formation of virus-induced MLAs. Analysis of the five viral proteins and replicated viral DNA shows that the maturation sequence of RC and AC is not completed in many cells, suggesting that virus production and release is carried out by a rather limited number of cells. This study thus lays the groundwork for further investigation of the replication cycle of beta-herpesviruses, and the results should be incorporated into plans for high-throughput and single-cell analytic approaches.

Type of Anion Largely Determines Salinity Tolerance in Four Rumex Species.

The aim of the present study was to compare the effect of various salts composed of different cations (Na+, K+) and anions (chloride, nitrate, nitrite) on growth, development and ion accumulation in three Rumex species with accessions from sea coast habitats (Rumex hydrolapathum, Rumex longifolius and Rumex maritimus) and Rumex confertus from an inland habitat. Plants were cultivated in soil in an experimental automated greenhouse during the autumn-winter season. Nitrite salts strongly inhibited growth of all Rumex species, but R. maritimus was the least sensitive. Negative effects of chloride salts were rather little-pronounced, but nitrates resulted in significant growth stimulation, plant growth and development. Effects of Na+ and K+ at the morphological level were relatively similar, but treatment with K+ salts resulted in both higher tissue electrolyte levels and proportion of senescent leaves, especially for chloride salts. Increases in tissue water content in leaves were associated with anion type, and were most pronounced in nitrate-treated plants, resulting in dilution of electrolyte concentration. At the morphological level, salinity responses of R. confertus and R. hydrolapathum were similar, but at the developmental and physiological level, R. hydrolapathum and R. maritimus showed more similar salinity effects. In conclusion, the salinity tolerance of all coastal Rumex species was high, but the inland species R. confertus was the least tolerant to salinity. Similarity in effects between Na+ and K+ could be related to the fact that surplus Na+ and K+ has similar fate (including mechanisms of uptake, translocation and compartmentation) in relatively salt-tolerant species. However, differences between various anions are most likely related to differences in physiological functions and metabolic fate of particular ions.

Micellization: A new principle in the formation of biomolecular condensates.

Phase separation is a fundamental mechanism for compartmentalization in cells and leads to the formation of biomolecular condensates, generally containing various RNA molecules. RNAs are biomolecules that can serve as suitable scaffolds for biomolecular condensates and determine their forms and functions. Many studies have focused on biomolecular condensates formed by liquid-liquid phase separation (LLPS), one type of intracellular phase separation mechanism. We recently identified that paraspeckle nuclear bodies use an intracellular phase separation mechanism called micellization of block copolymers in their formation. The paraspeckles are scaffolded by NEAT1_2 long non-coding RNAs (lncRNAs) and their partner RNA-binding proteins (NEAT1_2 RNA-protein complexes [RNPs]). The NEAT1_2 RNPs act as block copolymers and the paraspeckles assemble through micellization. In LLPS, condensates grow without bound as long as components are available and typically have spherical shapes to minimize surface tension. In contrast, the size, shape, and internal morphology of the condensates are more strictly controlled in micellization. Here, we discuss the potential importance and future perspectives of micellization of block copolymers of RNPs in cells, including the construction of designer condensates with optimal internal organization, shape, and size according to design guidelines of block copolymers.

Positively charged mineral surfaces promoted the accumulation of organic intermediates at the origin of metabolism.

Identifying plausible mechanisms for compartmentalization and accumulation of the organic intermediates of early metabolic cycles in primitive cells has been a major challenge in theories of life's origins. Here, we propose a mechanism, where positive membrane potentials elevate the concentration of the organic intermediates. Positive membrane potentials are generated by positively charged surfaces of protocell membranes due to accumulation of transition metals. We find that (i) positive membrane potentials comparable in magnitude to those of modern cells can increase the concentration of the organic intermediates by several orders of magnitude; (ii) generation of large membrane potentials destabilize ion distributions; (iii) violation of electroneutrality is necessary to induce nonzero membrane potentials; and (iv) violation of electroneutrality enhances osmotic pressure and diminishes reaction efficiency, resulting in an evolutionary driving force for the formation of lipid membranes, specialized ion channels, and active transport systems.

Post-Synapses in the Brain: Role of Dendritic and Spine Structures.

Brain synapses are neuronal structures of the greatest interest. For a long time, however, the knowledge about them was variable, and interest was mostly focused on their pre-synaptic portions, especially neurotransmitter release from axon terminals. In the present review interest is focused on post-synapses, the structures receiving and converting pre-synaptic messages. Upon further modulation, such messages are transferred to dendritic fibers. Dendrites are profoundly different from axons; they are shorter and of variable thickness. Their post-synapses are of two types. Those called flat/intended/aspines, integrated into dendritic fibers, are very frequent in inhibitory neurons. The spines, small and stemming protrusions, connected to dendritic fibers by their necks, are present in almost all excitatory neurons. Several structures and functions including the post-synaptic densities and associated proteins, the nanoscale mechanisms of compartmentalization, the cytoskeletons of actin and microtubules, are analogous in the two post-synaptic forms. However other properties, such as plasticity and its functions of learning and memory, are largely distinct. Several properties of spines, including emersion from dendritic fibers, growth, change in shape and decreases in size up to disappearance, are specific. Spinal heads correspond to largely independent signaling compartments. They are motile, their local signaling is fast, however transport through their thin necks is slow. When single spines are activated separately, their dendritic effects are often lacking; when multiple spines are activated concomitantly, their effects take place. Defects of post-synaptic responses, especially those of spines, take place in various brain diseases. Here alterations affecting symptoms and future therapy are shown to occur in neurodegenerative diseases and autism spectrum disorders.

Modeling of the compartmentalization effect induced by leading-edge tubercles

As a passive flow control technique, the use of leading-edge tubercles inspired by humpback whale flippers has attracted much interest. It is believed that one of the flow control mechanisms of leading-edge tubercles is compartmentalization, which is similar to the way in which wing fences act. However, to date, there has been no direct evidence for this belief. In view of this, the present work aims to verify and quantitatively describe the compartmentalization effect induced by leading-edge tubercles. Numerical simulation is performed to investigate the flow structures on a wavy airfoil with leading-edge tubercles, and the results reveal the presence of typical biperiodic flow patterns when a critical angle of attack is exceeded. Based on the flow characteristics of the wavy airfoil, special fences paired in a diverging configuration are designed and positioned on the baseline airfoil. A modeling method is developed to determine the main parameters of the fence configurations. It is found that the fenced airfoils designed using this method are able to reproduce the typical flow characteristics of the wavy airfoil under different inflow conditions. The spanwise distributions of the sectional airfoil performance under flow control by leading-edge tubercles and by the specially designed fences are very similar. A combined mechanism mainly including the lifting-line theory and the compartmentalization theory is proposed to provide a more comprehensive picture of the flow dynamic of leading-edge tubercles. This work provides strong evidence to confirm the compartmentalization mechanism of action of leading-edge tubercles, as well as developing a quantitative modeling method, both of which are important for fully understanding the underlying mechanism and guiding further optimization of this passive flow control technique.