Chemical Signals Research Articles

Identification of alarm pheromone components of the southern giant Asian hornet, Vespa soror, a major pest of honey bees.

The rise of biological invasions threatens biodiversity and food security, with the vespid family, including Vespa soror, being of particular concern. Our study focused on the alarm pheromone components of V. soror. By using gas chromatography-mass spectrometry (GC-MS) chemical analyses, electroantennograms, and field bioassays, we identified 5 compounds-2-pentanol, 3-methyl-1-butanol, 2-heptanol, 2-nonanol (2-N), and isopentyl acetate (IPA)-in hornet sting venom that elicited defensive behavior from hornets. IPA and 2-N also serve as alarm pheromone components in multiple honey bee species that are important prey for V. soror. This shared chemical signaling may allow cross-detection by each species on the other's alarm cues. While it should be advantageous for bees to detect V. soror alarm pheromone, the benefits to V. soror of using IPA and 2-N are unclear. V. soror may manipulate bee behavior, potentially distracting defenders, because they mark victim bee colonies by rubbing their abdomens, which contain their sting glands, at bee hive entrances. Our findings pose new evolutionary questions about the role of manipulation in the arms races.

Sensitive response of erosion and weathering to the Indian Summer Monsoon changes in South Asia during Dansgaard-Oeschger oscillations

Continental weathering plays a key role in regulating the long-term climate stability via negative feedback. However, whether and how erosion and weathering respond to rapid climate change (e.g millennial scale) in large river basins remains unclear, partly due to the lack of archives with robust age models and high sampling resolution. As one of the largest sediment source-to-sink systems, the Himalaya-Ganga/Brahmaputra River-Bay of Bengal system is considered as an ideal laboratory for examining the weathering-climate relationships over the past. Here we present the elemental and mineralogical data from well age-constrained core sediments in the Bay of Bengal, which document the erosion and weathering conditions in South Asia during the last glacial period. All proxies generally show larger values during glacial interstadials than the stadials, consistent with the millennial variabilities of regional sea surface temperature (SST) and the Indian Summer Monsoon (ISM) strength. We confirm that the erosion and chemical weathering signals in Ganga/Brahmaputra River basins, which sensitively respond to the ISM strength and/or temperature change, could be propagated through the large river systems and faithfully preserved in the South Asian marginal seas, without noticeable time lag on a millennial scale. Our findings provide valuable data for response of erosion and weathering dynamics in a large river basin to rapid climate changes, and highlight the immense potential of monsoon-driven continental silicate weathering in floodplains as a substantial short-term carbon sink, thus underscoring a pivotal natural carbon sequestration mechanism amidst the escalating threat of global warming.

Visualizing PIEZO1 Localization and Activity in hiPSC-Derived Single Cells and Organoids with HaloTag Technology.

PIEZO1 is critical to numerous physiological processes, transducing diverse mechanical stimuli into electrical and chemical signals. Recent studies underscore the importance of visualizing endogenous PIEZO1 activity and localization to understand its functional roles. To enable physiologically and clinically relevant studies on human PIEZO1, we genetically engineered human induced pluripotent stem cells (hiPSCs) to express a HaloTag fused to endogenous PIEZO1. Combined with advanced imaging, our chemogenetic platform allows precise visualization of PIEZO1 localization dynamics in various cell types. Furthermore, the PIEZO1-HaloTag hiPSC technology facilitates the non-invasive monitoring of channel activity across diverse cell types using Ca 2+ -sensitive HaloTag ligands, achieving temporal resolution approaching that of patch clamp electrophysiology. Finally, we used lightsheet imaging of hiPSC-derived neural organoids to achieve molecular scale imaging of PIEZO1 in three-dimensional tissue organoids. Our advances offer a novel platform for studying PIEZO1 mechanotransduction in human cells and tissues, with potential for elucidating disease mechanisms and targeted therapeutic development.

The Ortholog Receptor Or67d in Drosophila Bipectinata is able to Detect Two Different Pheromones

Sex pheromones play a crucial role in species recognition and reproductive isolation. Despite being largely species-specific in drosophilids, the mechanisms underlying pheromone detection, production, and their influence on mating behavior remain poorly understood. Here, we compare the chemical profiles of Drosophila bipectinata and D. melanogaster, the mating behaviors in both species, as well as the tuning properties of Or67d receptors, which are expressed by neurons in antennal trichoid sensilla at1. Through single sensillum recordings, we demonstrate that the D. bipectinata Or67d-ortholog exhibits similar sensitivity to cis-vaccenyl acetate (cVA) as compared to D. melanogaster but in addition also responds uniquely to (Z)-11-eicosen-1-yl-acetate (Z11-20:Ac), a compound exclusively produced by D. bipectinata males. Through courtship behavior assays we found that, surprisingly, perfuming the flies with Z11-20:Ac did not reveal any aphrodisiacal or anti-aphrodisiacal effects in mating assays. The behavioral relevance of at1 neuron channels in D. bipectinata compared to D. melanogaster seems to be restricted to its formerly shown function as an aggregation pheromone. Moreover, the non-specific compound cVA affected copulation negatively in D. bipectinata and could potentially act as a premating isolation barrier. As both ligands of Or67d seem to govern different behaviors in D. bipectinata, additional neurons detecting at least one of those compounds might be involved. These results underscore the complexity of chemical signaling in species recognition and raise intriguing questions about the evolutionary implications of pheromone detection pathways in Drosophila species.

Biostimulation methods based on chemical communication improve semen quality in male breeder rabbits

Biostimulation aims to optimize reproductive parameters as part of animal management practices by modulating animal sensory systems. Chemical signals, mostly known as pheromones, have a great potential in this regard. This study was conducted to determine the influence of short-term male rabbit exposure to different biological secretions, potentially pheromone-mediated, on reproductive parameters of males. Four groups of 18 males each were exposed to A) doe urine, B) 2-phenoxyethanol, C) doe vaginal swab, and D) distilled water (control), three times over a 2.5h exposure window, just before semen collection. Semen volume, sperm concentration and motility, as well as subpopulation analysis of the spermatozoa were assessed for each condition. Additionally, testosterone levels in blood samples were monitored at five time points over the 2.5 h exposure window. We found a higher percentage of motile, progressive, fast progressive and mid-progressive spermatozoa in any of the three experimental groups compared to the control group. In contrast, the semen volume and the percentage of immotile and non-progressive spermatozoa was generally higher in the control group. We then identified a higher proportion of a subpopulation of fast and progressive spermatozoa in groups A, B, and C compared to group D. Our data indicates that sperm motility increases when animals are exposed to specific biological fluids potentially containing pheromones, and that an increase in sperm volume does not correlate with an increase in spermatozoa concentration, progressiveness, and speed. Finally, no differences in testosterone levels were found among comparisons, although males of groups A and C (exposed to natural female biological fluids) showed a tendency towards higher testosterone levels. In conclusion, our results indicate that rabbit sperm quality increases upon exposure to the biological secretions proposed, thereby supporting further investigation into their molecular identity. This exploration could eventually pave the way for implementing the use of pheromones in rabbit husbandry to enhance reproductive and productive parameters in farmed rabbits.

Photoswitchable Metal-Organic Framework as a Smart Nanoreactor for Ultraviolet Light-Enhanced Confined Catalysis.

Confined catalysis, where a chemical reaction is accommodated within a nanoscale host, provides an effective approach to control the pathways and outcomes of catalytic transformations. However, the confinement effect is typically limited to a fixed rate and/or selectivity once the nanohost is chosen. Herein, we developed a photoresponsive metal-organic framework (MOF) as a "smart" nanohost to realize ultraviolet (UV) light-enhanced confined catalysis of Knoevenagel condensation. Photoresponsive MOF of Zn-ADA was thus prepared by solvothermal strategy where azobenzene-4,4'-dicarboxylic acid (ADA) was used as the photoactive linker to coordinate with zinc nitrate. Characterization results suggested that UV light could decrease the pore size of Zn-ADA due to suppressed bending of the azobenzene-containing ADA linker in Zn-ADA. It enforced the proximity between substrates and catalytic groups within the confined space, and thus enhanced the confinement effect on Knoevenagel condensation. The UV light-enhanced confined catalysis enabled the translation of light stimulus into chemical signal, which may open up new control on the basis of the specific reaction field.

Direct and indirect effects of copepod grazers on community structure

Abstract Ecological theory and empirical research show that both direct lethal effects and indirect non-lethal effects can structure the composition of communities. While the direct effects of grazers on marine phytoplankton communities are well studied, their indirect effects are still poorly understood. Direct and indirect effects are inherently difficult to disentangle in plankton food webs. In this study we evaluate the indirect effects of copepod grazers on community function and structure using isolated chemical alarm signals, copepodamides. We expose intact summer and spring communities to direct grazing from copepods, or to chemical alarm cues without the presence of grazers in controlled experiments. The effects of direct grazing on ecosystem function were moderate in both experiments as indicated by levels of chlorophyll and primary production. Indirect and direct effects resulted in changes in the composition of both the eukaryote and prokaryote communities as shown by metabarcoding of 18S and 16S rRNA. Size structure analysis suggests that direct grazing and copepodamide exposure both favoured smaller organisms (< 10–15 μm) corroborating the size-structuring effect of copepod grazers. We conclude that the well-established effect of copepods on phytoplankton communities results from a combination of direct and indirect effects. This is a first attempt to isolate indirect effects of copepods on community structure and the results suggest that a full mechanistic understanding of the structuring effect of copepods will require insights to both direct and indirect effects of consumers as demonstrated for other ecosystems components.

New estimates of sulfate diffusion rates in the EPICA Dome C ice core

Abstract. To extract climatically relevant chemical signals from the deepest, oldest Antarctic ice, we must first investigate the degree to which chemical ions diffuse within solid ice. Volcanic sulfate peaks are an ideal target for such an investigation because they are high-amplitude, short-duration (∼3 years) events with a quasi-uniform structure. Here we present an analysis of the EPICA Dome C sulfate record over the last 450 kyr. We identify volcanic peaks and isolate them from the non-sea-salt sulfate background to reveal the effects of diffusion: amplitude damping and broadening of peaks in the time domain with increasing depth and age. Sulfate peak shape is also altered by the thinning of ice layers with depth that results from ice flow. Both processes must be simulated to derive effective diffusion rates. This is achieved by running a forward model to diffuse idealised sulfate peaks at different rates while also accounting for ice thinning. Our simulations suggest a median effective diffusion rate of sulfate ions of 2.4±1.7×10-7 m2 yr−1 in Holocene ice, slightly faster than suggested by previous work. The effective diffusion rate observed in deeper ice is significantly lower, and Holocene ice shows the highest rate of the last 450 kyr. Beyond the Holocene, there is no systematic difference between the effective diffusion rates of glacial and interglacial periods despite variations in soluble ion concentrations, dust loading, and ice grain radii. Effective diffusion rates for 40 to 200 ka are relatively constant and of the order 1×10-8 m2 yr−1. Our results suggest that the diffusion of sulfate ions within volcanic peaks is relatively fast initially, perhaps through an interconnected vein network, but slows significantly after 40 kyr. In the absence of clear evidence for a controlling influence of temperature on sulfate diffusivity with depth and age, we hypothesise that the rapid decrease in effective diffusion rate from the time of deposition to ice of 50 ka age may be due to a switch in the mechanism of diffusion resulting from the changing location of sulfate ions within the ice microstructure and/or interconnectedness of veins and grain boundaries.

Chimera states and eigen microstates of nonidentical power-law coupled oscillators with heterogeneous phase lag

Chimera state is a special spatiotemporal patterns where coherent and incoherent states coexist, not only related to neuronal evolution but also to diseases such as parkinson, epilepsy, and schizophrenia. In many studies of biological networks, the interaction patterns between individuals often exhibit a scale-free heavy-tailed distribution. Hence, researches into chimera state within scale-free structures may help to understand the close relationship between function and structure in biological systems. Especially in neural systems, interactions between neurons depend on both electrical and chemical signals, naturally involving heterogeneous delay effects. In this study, we introduce power-law coupling, nonidentical natural frequency, and heterogeneous phase delay into the phase oscillator model, exploring the relationship between oscillator coupled strength, power-law exponent, and the emergence of chimera state. Other important thing is that we extend the Eigen Microstate (EM) method to investigate the criticality, attempting to reveal the mechanism of chimera state emergence through the mesoscopic structure of eigen microstate. We find that the critical analysis results of the EM method, relying solely on phase data, are entirely consistent with those obtained by the mean-field method, revealing the inevitable relationship between the emergence of chimera state and the structure–power law coupling. In addition, the spatiotemporal patterns of eigen microstate provide insights into the mesoscopic structure, can be used to distinguish spatial distribution of synchronization, chimera state, and disorder state, as well as their characteristic dynamics of oscillators. This expansion research of the EM method will advance the exploration of criticality in real oscillatory systems.

Attraction of Nicotiana benthamiana to Bemisia tabaci is related to a chemical signal in plant volatile, undecane.

The whitefly Bemisia tabaci is one of the world's foremost agricultural pests. Recently, we found that a wild relative of tobacco (Nicotiana benthamiana) demonstrates remarkable attractiveness and nearly 100% lethality towards whiteflies. Therefore, it can act as a dead-end trap crop for whitefly control in the field. However, the underlying mechanism of the significant attractiveness of N. benthamiana towards whiteflies is unclear. Binary-choice assays and olfactory experiments showed that compared to common tobacco (N. tabacum), the volatile of N. benthamiana has a greater attraction to whiteflies. Then we analyzed and compared volatiles from these two Nicotiana species by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). We identified 16 chemical compounds that are more abundant in N. benthamiana than in N. tabacum. Seven compounds were further tested with olfactometer assays and we found that, among them, undecane strongly attracted whiteflies. Further experiments revealed that even 0.005 μg mL-1 undecane is attractive to whiteflies. We also silenced the genes that may influence the biosynthesis of undecane and found the production of undecane decreased after silencing NbCER3, and that N. benthamiana plants with less undecane lost their attraction to whiteflies. In addition, we found that applying 0.005 μg mL-1 undecane on yellow sticky traps can increase the number of stuck insects on the traps by ≈40%. Undecane from the volatile of N. benthamiana is a critical chemical signal that attracts whiteflies and NbCER3 involved in the biosynthesis of undecane. Undecane may be used to improve the efficiency of yellow sticky traps for whitefly control. © 2024 Society of Chemical Industry.

Behavior in time of solutions to a degenerate chemotaxis system with flux limitation

We study a new class of Keller–Segel models, which presents a limited flux and an optimal transport of cells density according to chemical signal density. As a prototype of this class we study radially symmetric solutions to the parabolic–elliptic system ut=∇⋅(u∇uu2+|∇u|2)−χkf∇⋅(u∇v(1+|∇v|2)α),x∈Ω,t>0,0=Δv−μ+u,x∈Ω,t>0under no flux boundary conditions in a ball B=Ω⊂RN and initial condition u(x,0)=u0(x)>0,χ>0,α>0,kf>0 and μ=1|Ω|∫Ωu0dx. Under suitable conditions on α and u0 it is shown that the solution blows up in L∞-norm at a finite time Tmax and for some p>1 it blows up also in Lp-norm. The proofs are mainly based on an helpful change of variables, on comparison arguments and some suitable estimates.

Pseudomonas aeruginosa modulates both Caenorhabditis elegans attraction and pathogenesis by regulating nitrogen assimilation

Detecting chemical signals is important for identifying food sources and avoiding harmful agents. Like many animals, C. elegans use olfaction to chemotax towards their main food source, bacteria. However, little is known about the bacterial compounds governing C. elegans attraction to bacteria and the physiological importance of these compounds to bacteria. Here, we address these questions by investigating the function of a small RNA, P11, in the pathogen, Pseudomonas aeruginosa, that was previously shown to mediate learned pathogen avoidance. We discovered that this RNA also affects the attraction of untrained C. elegans to P. aeruginosa and does so by controlling production of ammonia, a volatile odorant produced during nitrogen assimilation. We describe the complex regulation of P. aeruginosa nitrogen assimilation, which is mediated by a partner-switching mechanism involving environmental nitrates, sensor proteins, and P11. In addition to mediating C. elegans attraction, we demonstrate that nitrogen assimilation mutants perturb bacterial fitness and pathogenesis during C. elegans infection by P. aeruginosa. These studies define ammonia as a major mediator of trans-kingdom signaling, implicate nitrogen assimilation as important for both bacteria and host organisms, and highlight how a bacterial metabolic pathway can either benefit or harm a host in different contexts.

A Microrobotic Design for the Spontaneous Tracing of Isochemical Contours in the Environment

Microrobotic platforms hold significant potential to advance a variety of fields, from medicine to environmental sensing. Herein, minimally functional robotic entities modeled on readily achievable state‐of‐the‐art features in a modern lab or cleanroom are computationally simulated. Inspired by Dou and Bishop (Phys Rev Res. 2019;1(3):1–5), it is shown that the simple combination of unidirectional steering connected to a single environmental (chemical) sensor along with constant propulsion gives rise to highly complex functions of significant utility. Such systems can trace the contours orthogonal to arbitrary chemical gradients in the environment. Also, pairs of such robots that are additionally capable of emitting the same chemical signal are shown to exhibit coupled relative motion. When the pair has unidirectional steering in opposite directions within the 2D plane (i.e., counter‐rotating), they move in parallel trajectories to each other. Alternatively, when steering is in the same direction (corotation), the two move in the same epicyclical trajectory. In this way, the chirality of the unidirectional steering produces two distinct emergent phenomena. The behavior is understood as a ratchet mechanism that exploits the differential in the radii of curvature corresponding to different spatial locations. Applications to environmental detection, remediation, and monitoring are discussed.

Insights into Women's health: Exploring the vaginal microbiome, quorum sensing dynamics, and therapeutic potential of quorum sensing quenchers

The vaginal microbiome is an important aspect of women's health that changes dynamically with various stages of the woman's life. Just like the gut microbiome, the vaginal microbiome can also be affected by pathologies that dramatically change the typical composition of native vaginal microorganisms. However, the mechanism as to how both vaginal endemic and gut endemic opportunistic microbes can express pathogenicity in vaginal polymicrobial biofilms is poorly understood. Quorum sensing is the cellular density-dependent bacterial and fungal communication process in which chemical signaling molecules, known as autoinducers, activate expression for genes responsible for virulence and pathogenicity, such as biofilm formation and virulence factor production. Quorum sensing inhibition, or quorum quenching, has been explored as a potential therapeutic route for both bacterial and fungal infections. By applying these quorum quenchers, one can reduce biofilm formation of opportunistic vaginal microbes and combine them with antibiotics for a synergistic effect. This review aims to display the relationship between the vaginal and gut microbiome, the role of quorum sensing in polymicrobial biofilm formation which cause pathology in the vaginal microbiome, and how quorum quenchers can be utilized to attenuate the severity of bacterial and fungal infections.

Programming gel automata shapes using DNA instructions

The ability to transform matter between numerous physical states or shapes without wires or external devices is a major challenge for robotics and materials design. Organisms can transform their shapes using biomolecules carrying specific information and localize at sites where transitions occur. Here, we introduce gel automata, which likewise can transform between a large number of prescribed shapes in response to a combinatorial library of biomolecular instructions. Gel automata are centimeter-scale materials consisting of multiple micro-segments. A library of DNA activator sequences can each reversibly grow or shrink different micro-segments by polymerizing or depolymerizing within them. We develop DNA activator designs that maximize the extent of growth and shrinking, and a photolithography process for precisely fabricating gel automata with elaborate segmentation patterns. Guided by simulations of shape change and neural networks that evaluate gel automata designs, we create gel automata that reversibly transform between multiple, wholly distinct shapes: four different letters and every even or every odd numeral. The sequential and repeated metamorphosis of gel automata demonstrates how soft materials and robots can be digitally programmed and reprogrammed with information-bearing chemical signals.

Male–female chemical interactions in a facultatively parthenogenetic stick insect

AbstractFacultative parthenogenesis is a form of reproduction in which females can either lay unfertilised eggs that typically develop into female offspring only or mate and lay fertilised eggs that develop into male and female offspring. Intriguingly, facultative parthenogens often occur in mixed‐sex populations where reproduction is mostly sexual and all‐female populations where reproduction is asexual. How all‐female populations avoid invasion by males remains unknown. Here, we explored the use of pheromones in male–female communication in a facultatively parthenogenetic stick insect, the peppermint stick insect (Megacrania batesii), and compared chemical signals between females descended from sexually versus parthenogenetically reproducing populations. If parthenogenetic females release less attractive pheromones, this could help explain the persistence of all‐female populations. We found that M. batesii exhibits slight sexual dimorphism in antenna morphology, and behavioural assays provided little evidence that males could locate females solely by volatile pheromones. However, CHC profiles differed substantially between different types of females. Analysis of CHC components indicated a clear genetic difference between females descended from all‐female versus mixed‐sex populations, as well as a maternal effect of female parthenogenetic versus sexual development. Together, our results suggest that males might rely more on close‐range chemical cues to differentiate females, and chemical communication could play a role in the persistence of all‐female populations.

Cell blebbing novel therapeutic possibilities to counter metastasis.

Cells constantly reshape there plasma membrane and cytoskeleton during physiological and pathological processes (Hagmann et al. in J Cell Biochem 73:488-499, 1999). Cell blebbing, the formation of bulges or protrusions on the cell membrane, is related to mechanical stress, changes in intracellular pressure, chemical signals, or genetic anomalies. These membrane bulges interfere with the force balance of actin filaments, microtubules, and intermediate filaments, the basic components of the cytoskeleton (Charras in J Microsc 231:466-478,2008). In the past, these blebs with circular structures were considered apoptotic markers (Blaser et al. in Dev Cell 11:613-627,2006). Cell blebbing activates phagocytes and promotes the rapid removal of intrinsic compartments. However, recent studies have revealed that blebbing is associated with dynamic cell reorganization and alters the movement of cells in-vivo and in-vitro (Charras and Paluch in Nat Rev Mol Cell Biol 9:730-736,2008). During tumor progression, blebbing promotes invasion of cancer cells into blood, and lymphatic vessels, facilitating tumor progression and metastasis (Weems et al. in Nature 615:517-525,2023). Blebbing is a dominant feature of tumor cells generally absent in normal cells. Restricting tumor blebbing reduces anoikis resistance (survival in suspension) (Weems et al. in Nature 615:517-525,2023). Hence, therapeutic intervention with targeting blebbing could be highly selective for proliferating pro-metastatic tumor cells, providing a novel therapeutic pathway for tumor metastasis with minimal side effects. Here, we review the association between cell blebbing and tumor cells, to uncover new research directions and strategies for metastatic cancer therapy. Finaly, we aim to identify the druggable targets of metastatic cancer in relation to cell blebbing.

Novel and classical methods similarly describe variation in territory size among males in Neotropical poison frogs with contrasting reproductive and behavioral strategies

Territoriality is a form of social dominance concerning the use of space that ensures the territory owner primary access to critical resources. The territory is defended with visual displays, advertisement calls, physical attacks, or chemical signals. The territory is frequently estimated by mapping locations where an animal is observed engaging in territorial behavior or by tracking. However, these approaches may over- or underestimate the areas defended. Thus, the use of approaches explicitly determining defended areas is critical to properly characterize the territory. Intrusion experiments can elicit a response in territory holders, allowing one to characterize their aggressive responses; however, the aggressive response depends on the species. We describe an approach to experimentally estimate the territory size using playback experiments in a species that exhibits a stereotypical phonotactic response: the nurse frog, Allobates aff. trilineatus and develop a new behavioral index that allows assessing territory size in response to playbacks for a species with non-stereotyped phonotactic response: the endangered Lehmann’s poison frog, Oophaga lehmanni. We conducted 772 playback experiments on 18 males of A. aff. trilineatus, and 222 on nine males of O. lehmanni. We analyzed the results of playback experiments with three different area estimators regularly used to estimate space use and evaluated whether these estimates are correlated. The shape and size of territories varied among individuals and estimators in both species. Although we found that the absolute size of the territory depends on the method used, estimates were strongly correlated, meaning that different estimators similarly describe variation in territory size among males. Choosing an analysis method may not be particularly important for studying the characteristics of territoriality over space and time but using a systematic and standardized experimental approach that also incorporates the particularities of the aggressive response of each species is essential to understand the evolution of space use by poison frogs and other territorial species.

Multi-class plant hormone HILIC-MS/MS analysis coupled with high-throughput phenotyping to investigate plant-environment interactions.

Plant hormones are chemical signals governing almost every aspect of a plant's life cycle and responses to environmental cues. They are enmeshed within complex signaling networks that can only be deciphered by using broad-scale analytical methods to capture information about several plant hormone classes simultaneously. Methods used for this purpose are all based on reversed-phase (RP) liquid chromatography and mass spectrometric detection. Hydrophilic interaction chromatography (HILIC) is an alternative chromatographic method that performs well in analyses of biological samples. We therefore developed and validated a HILIC method for broad-scale plant hormone analysis including a rapid sample preparation procedure; moreover, derivatization or fractionation is not required. The method enables plant hormone screening focused on polar and moderately polar analytes including cytokinins, auxins, jasmonates, abscisic acid and its metabolites, salicylates, indoleamines (melatonin), and 1-aminocyclopropane-1-carboxylic acid (ACC), for a total of 45 analytes. Importantly, the major pitfalls of ACC analysis have been addressed. Furthermore, HILIC provides orthogonal selectivity to conventional RP methods and displays greater sensitivity, resulting in lower limits of quantification. However, it is less robust, so procedures to increase its reproducibility were established. The method's potential is demonstrated in a case study by employing an approach combining hormonal analysis with phenomics to examine responses of three Arabidopsis ecotypes toward three abiotic stress treatments: salinity, low nutrient availability, and their combination. The case study showcases the value of the simultaneous determination of several plant hormone classes coupled with phenomics data when unraveling processes involving complex cross-talk under diverse plant-environment interactions.

Electrocatalysis in MOF Films for Flexible Electrochemical Sensing: A Comprehensive Review.

Flexible electrochemical sensors can adhere to any bendable surface with conformal contact, enabling continuous data monitoring without compromising the surface's dynamics. Among various materials that have been explored for flexible electronics, metal-organic frameworks (MOFs) exhibit dynamic responses to physical and chemical signals, offering new opportunities for flexible electrochemical sensing technologies. This review aims to explore the role of electrocatalysis in MOF films specifically designed for flexible electrochemical sensing applications, with a focus on their design, fabrication techniques, and applications. We systematically categorize the design and fabrication techniques used in preparing MOF films, including in situ growth, layer-by-layer assembly, and polymer-assisted strategies. The implications of MOF-based flexible electrochemical sensors are examined in the context of wearable devices, environmental monitoring, and healthcare diagnostics. Future research is anticipated to shift from traditional microcrystalline powder synthesis to MOF thin-film deposition, which is expected to not only enhance the performance of MOFs in flexible electronics but also improve sensing efficiency and reliability, paving the way for more robust and versatile sensor technologies.