Organisms Research Articles

Green Synthesis of Carboxymethyl Chitosan-Based CuInS2 QDs with Luminescent Response toward Pb2+ Ion and Its Application in Bioimaging.

Polysaccharide-based QDs have attracted great attention in the field of biological imaging and diagnostics. How to get rid of the high heavy metal toxicity resulting from conventional Cd- and Pb-based QDs is now the main challenge. Herein, we offer a simple and environmentally friendly approach for the "direct" interaction of thiol-ending carboxymethyl chitosan (CMC-SH) with metal salt precursors, resulting in CuInS2 QDs based on polysaccharides. A nucleation-growth mechanism based on the LaMer model can explain how CMC-CuInS2 QDs are formed. As-prepared water-soluble CMC-CuInS2 QDs exhibit monodisperse particles with sizes of 5.5-6.5 nm. CMC-CuInS2 QDs emit the bright-green fluorescence at 530 nm when excited at 466 nm with the highest quantum yield of ∼18.0%. Meanwhile, the fluorescence intensity of CMC-CuInS2 QD aqueous solution is quenched with the addition of Pb2+ and the minimal limit of detection is as little as 0.4 nM. Furthermore, due to its noncytotoxicity, great biocompatibility, and strong biorecognition ability, CMC-CuInS2 QDs can be exploited as a possible cell membrane imaging reagent. The imaging studies also demonstrate that CMC-CuInS2 QDs are suitable for Pb2+ detection in live cells and living organisms (zebrafish). Thus, this work offers such an efficient, green, and practical method for creating low-toxicity and water-soluble QD nanosensors for a sensitive and selective detection of toxic metal ion in live cells and organisms.

ComsystanJ: A collection of Fiji/ImageJ2 plugins for nonlinear and complexity analysis in 1D, 2D and 3D.

Complex systems such as the global climate, biological organisms, civilisation, technical or social networks exhibit diverse behaviours at various temporal and spatial scales, often characterized by nonlinearity, feedback loops, and emergence. These systems can be characterized by physical quantities such as entropy, information, chaoticity or fractality rather than classical quantities such as time, velocity, energy or temperature. The drawback of these complexity quantities is that their definitions are not always mathematically exact and computational algorithms provide estimates rather than exact values. Typically, evaluations can be cumbersome, necessitating specialized tools. We are therefore introducing ComsystanJ, a novel and user-friendly software suite, providing a comprehensive set of plugins for complex systems analysis, without the need for prior programming knowledge. It is platform independent, end-user friendly and extensible. ComsystanJ combines already known algorithms and newer methods for generalizable analysis of 1D signals, 2D images and 3D volume data including the generation of data sets such as signals and images for testing purposes. It is based on the framework of the open-source image processing software Fiji and ImageJ2. ComsystanJ plugins are macro recordable and are maintained as open-source software. ComsystanJ includes effective surrogate analysis in all dimensions to validate the features calculated by the different algorithms. Future enhancements of the project will include the implementation of parallel computing for image stacks and volumes and the integration of artificial intelligence methods to improve feature recognition and parameter calculation.

Fluorescent sensors for imaging of interstitial calcium

Calcium in interstitial fluids is central to systemic physiology and a crucial ion pool for entry into cells through numerous plasma membrane channels. Its study has been limited by the scarcity of methods that allow monitoring in tight inter-cell spaces of living tissues. Here we present high performance ultra-low affinity genetically encoded calcium biosensors named GreenT-ECs. GreenT-ECs combine large fluorescence changes upon calcium binding and binding affinities (Kds) ranging from 0.8 mM to 2.9 mM, making them tuned to calcium concentrations in extracellular organismal fluids. We validated GreenT-ECs in rodent hippocampal neurons and transgenic zebrafish in vivo, where the sensors enabled monitoring homeostatic regulation of tissue interstitial calcium. GreenT-ECs may become useful for recording very large calcium transients and for imaging calcium homeostasis in inter-cell structures in live tissues and organisms.

Misconceptions about quantifying animal encounter and interaction processes

The ability to quantify when and where animals interact is key to the understanding of a plethora of ecological processes, from the structure of social communities and predator–prey relations to the spreading of pathogens and information. Despite the ubiquity of interaction processes among animals and the revolution in tracking technologies that now allows for the monitoring of multiple individuals simultaneously, a common theoretical framework with which to analyze movement data and extract interaction events is still lacking. Given the wide spectrum of mechanisms that governs how a biological organism detects the proximity of other organisms, most of the proposed theoretical approaches have been tailored to specific species or empirical situations and so far have been lacking a common currency with which to evaluate and compare findings across taxa. Here, we propose such general framework by borrowing techniques from statistical physics, specifically from the theory of reaction diffusion processes. Some of these techniques have already been employed to predict analytically pathogen transmission events between pairs of animals living within home ranges, but have not yet pervaded the movement ecology literature. Using both continuous and discrete variables, we present the mathematical framework and demonstrate its suitability to study interaction processes. By defining interactions whenever a token of information is transferred from one individual to another, we show that the probability of transferring information for the first time is equivalent to the first-passage probability of reacting in a multi-target environment. As interaction events reduce to encounter events when information transfer is perfectly efficient, we compare our formalism to a recently proposed approach to study encounters. Such approach takes the joint occupation probability of two animals over a region of interaction as a measure of the probability of encounter, rather than the first-encounter probability. We show the discrepancy of the two approaches by analytically comparing their predictions with continuous variables, while with discrete space–time variables, we quantify their difference over time. We conclude by pointing to some of the open problems that the reaction diffusion formalism, alternatively, the reaction motion formalism, as it should be more appropriately called, might be able to tackle.

Coordinating upper limbs for octave playing on the piano via neuro-musculoskeletal modeling

Understanding the coordination of multiple biomechanical degrees of freedom in biological organisms is crucial for unraveling the neurophysiological control of sophisticated motor tasks. This study focuses on the cooperative behavior of upper-limb motor movements in the context of octave playing on the piano. While the vertebrate locomotor system has been extensively investigated, the coherence and precision timing of rhythmic movements in the upper-limb system remain incompletely understood. Inspired by the spinal cord neuronal circuits (central pattern generator, CPG), a computational neuro-musculoskeletal model is proposed to explore the coordination of upper-limb motor movements during octave playing across varying tempos and volumes. The proposed model incorporates a CPG-based nervous system, a physiologically-informed mechanical body, and a piano environment to mimic human joint coordination and expressiveness. The model integrates neural rhythm generation, spinal reflex circuits, and biomechanical muscle dynamics while considering piano playing quality and energy expenditure. Based on real-world human subject experiments, the model has been refined to study tempo transitions and volume control during piano playing. This computational approach offers insights into the neurophysiological basis of upper-limb motor coordination in piano playing and its relation to expressive features.

Do We Really Exist? Eastern Inspirations in Thomas Metzinger’s Self-model Theory of Subjectivity

This paper is an analysis of Thomas Metzinger’s self-model theory of subjectivity (SMT). Metzinger claims that beyond the biological organism and its properties, there is no individual and distinct entity that can be regarded as “self”. What really exists is the phenomenal sense of being self, which creates the illusion of the existence of something permanent. Taking the concepts of David Hume and certain early Buddhists thinkers as his starting point, Metzinger claims that during introspection, which is a type of phenomenal experience, we find nothing stable, but only impermanent impressions. As he argues, this hypothesis is supported by empirical neuroscience research, which should be considered when studying human subjectivity. Drawing extensively from the results of science and philosophy of mind, he proposes a concept of a phenomenal self-model (PSM). The PSM integrates information about the whole biological organism and makes it available from the first-person perspective. The first part of the paper presents the key issues of the SMT and the four aspects of Metzinger’s critique of the concept of the substantial self. The paper also offers a critical analysis of some of Metzinger’s ideas. The second section discusses the common features as well as differences between the SMT and the Buddhist concept of non-self (s. anātman, p. anattā). It also aims to analyse certain problematic issues of the notion of anattā and demonstrate some of the challenges connected with the use of a comparative method.

Microbial-earthworm ecofilters (MEES) for urban wastewater treatment

Water is an absolute necessity for life and water scarcity is a major problem all over the world. Reusing household wastewater for non-potable water applications is one of the solutions to tackle this problem. Many developing countries lack the technological resources to construct and operate costly wastewater treatment plants. They need cost-effective wastewater treatment options so that both economic aspects and human needs can be met easily. Centralized sewage treatment systems are unable to achieve future demands for sustainable wastewater management in developing countries due to the growing population and needs. The present work examines the effectiveness of treating urban wastewater with microbial-earthworm eco filters (MEEs) (reactor 2) and the filter unit without earthworms (reactor 1). Results of the use of the vermi-biofiltration wastewater treatment unit comprising the biological filtration treatment unit, Eisenia fetida earthworm species, live soil organisms, and natural stones to treat household wastewater are reported herein. The biological oxygen demand (BOD), total dissolved solids (TDS), chemical oxygen demand (COD), and total organic carbon (TOC) were monitored for seven weeks. These parameters exhibited a decreasing trend in both the filtration units. A 75 % reduction in TOC for reactor 2 shows the effectiveness of the proposed system for the utilization of wastewater from urban households. Reactor 2 also showed a reduction in BOD, COD, and TDS approximately in the range of 85, 90, and 30 % respectively. This technique seems to be useful for developing a low-cost and useful household purification system in water-scarce areas using harmless bio-organisms.

Preface

Intelligence emerging from interactions between the body and the environment at the material and morphological levels attracts the attention of many different research communities. Researchers with engineering, social sciences, computer sciences, biology, and materials science backgrounds all study and understand embodied intelligence from their own perspectives. Therefore, providing a common definition of ‘Embodied Intelligence’ remains challenging.Furthermore, the intricate connection between the body and mind remains an unresolved philosophical question. Exploring this relationship not only deepens our understanding of animals and humans but also serves as a crucial element in the development of embodied artificial intelligence. By unraveling this connection, we can pave the way for creating robots endowed with practical intelligence. The long-standing philosophical debates surrounding consciousness have gained utmost significance in the realm of AI-powered machines.This book presents a comprehensive selection of papers authored by renowned researchers who participated in the 2nd International Conference on Embodied Intelligence held on 23-25 March, 2022, and the Embodied Intelligence Workshop, held at the RoboSoft 2022 Conference. This collection features reviews and perspectives articles, as well as the original research. The collection aims to stimulate interdisciplinary discussions and presenting novel ideas on the topic of Embodied Intelligence. By exploring the latest concepts and future directions in this field, these papers offer fresh perspectives and help paving the way for breakthroughs in both understanding and practical implementation.The central focus of this year’s conference revolved around two key topics: the significance of modeling in the design of soft robots and the pivotal role of the brain in embodied agents. The design of soft robots can follow a modeling-based approach using formal models and optimization techniques, similar to traditional rigid robotics. However, accurately modeling the behavior of soft robots is challenging. An exploratory approach inspired by biological organisms involves an iterative process, drawing insights from their locomotion and other behaviors. The role of the brain and central nervous system in bio-inspired robotics is significant, with self-organization and embodied intelligence allowing problem-solving without extensive centralized control. Researchers emulate cognitive processes observed in animals to develop intelligent robots, requiring advances in computational models and algorithms. Finding a good balance between exploiting the physical body and relying on computational capabilities remains an open topic of discussion.The book consists of a wide range of topics surrounding Embodied Intelligence and is loosely structured in two parts. The first set of chapters discuss the principles and perspectives on Embodied Intelligence and the links to robotics and artificial life. In the second half of the book, there is discussion on the connection between humans and Embodied Intelligence and the surrounding philosophy, psychology and cognitive science which ground and situate the research.We express our sincere gratitude to all the participants of the Conference and Workshop participants, the authors, and the reviewers for their outstanding contributions to this volume.

LIVE BIOTHERAPEUTIC PRODUCT AND CANCER IMMUNOTHERAPY

Probiotics are defined as ‘’live microorganisms that, when administered in adequate amounts, confer a health benefit on the host’’ [1]. Compared to conventional probiotics, novel beneficial effects on human health by a wide range of microbial probiotics have been reported, and such probiotics are called as next-generation probiotics (NGP), which are defined as ‘’new beneficial probiotics different from classical probiotics of Lactobacillus and Bifidobacterium’’ [2]. NGPs include various bacterial species such as Faecalibacterium prausnitzii, Akkermansia muciniphila, Bacteroides fragilis/Bacteroides uniformis, Eubacterium hallii and cocktails of Clostridium clusters IV and XIVa [2]. According to the pharmaceutical application, NGPs with novel therapeutic functions are termed live biotherapeutic product (LBP) [3]. LBP is defined as ‘’a biological product that contains live organisms such as bacteria, and that is applicable to the prevention, treatment, or cure of a disease or condition of human beings’’. O’Toole et al. [3] listed several candidates of LBPs, and the biological functions targeted various diseases of the 11 strains of 8 bacterial species of Bacteroides xylanisolvens, Bacteroides ovatus, Bacteroides dorei, B. fragilis, Bacteroides acidifaciens, Clostridium butyricum, F. prausnitzii and Lactococcus lactis were shown. In the list, C. buryricum MIYAIRI588 strain was indicated to be effective for various diseases, including cancer, inflammation, and infectious diseases.

Selective and Site-Specific Incorporation of Nonstandard Amino Acids Within Proteins for Therapeutic Applications.

The incorporation of nonstandard amino acids (nsAAs) within protein sequences has broadened the chemical functionalities available for use in the study, prevention, or treatment of disease. The ability to genetically encode the introduction of nsAAs at precise sites of target recombinant proteins has enabled numerous applications such as bioorthogonal conjugation, thrombin inhibition, intrinsic biological containment of live organisms, and immunochemical termination of self-tolerance. Genetic systems that perform critical steps in enabling nsAA incorporation are known as orthogonal translation systems or orthogonal aminoacyl-tRNA synthetase/tRNA pairs. In Escherichia coli, several of these have been designed to accept novel nsAAs. Certain endogenous proteins, codon context, and standard amino acid concentrations can affect the yield of recombinant protein, the rate of nsAA incorporation within off-target proteins, and the rate of misincorporation due to near-cognate suppression or misacylation of orthogonal tRNA with standard amino acids. As a result, a significant body of work has been performed in engineering the E. coli genome to alleviate these issues. Here, we describe common methods applicable to nsAA incorporation within proteins in E. coli for sufficient purity and characterization for downstream therapeutic applications.

Characteristics of amino acid metabolism in colorectal cancer.

In recent years, metabolomics research has become a hot spot in the screening and treatment of cancer. It is a popular technique for the quantitative characterization of small molecular compounds in biological cells, tissues, organs or organisms. Further study of the tumor revealed that amino acid changes may occur early in the tumor. The rapid growth and metabolism required for survival result in tumors exhibiting an increased demand for amino acids. An abundant supply of amino acids is important for cancer to maintain its proliferative driving force. Changes in amino acid metabolism can be used to screen malignant tumors and improve therapeutic outcomes. Therefore, it is particularly important to study the characteristics of amino acid metabolism in colorectal cancer. This article reviews several specific amino acid metabolism characteristics in colorectal cancer.

Characterization of Lactobacilli Phage Endolysins and Their Functional Domains-Potential Live Biotherapeutic Testing Reagents.

Phage endolysin-specific binding characteristics and killing activity support their potential use in biotechnological applications, including potency and purity testing of live biotherapeutic products (LBPs). LBPs contain live organisms, such as lactic acid bacteria (LAB), and are intended for use as drugs. Our approach uses the endolysin cell wall binding domains (CBD) for LBP potency assays and the endolysin killing activity for purity assays. CBDs of the following five lactobacilli phage lysins were characterized: CL1, Jlb1, Lj965, LL-H, and ΦJB. They exhibited different bindings to 27 LAB strains and were found to bind peptidoglycan or surface polymers. Flow cytometry based on CBD binding was used to enumerate viable counts of two strains in the mixture. CL1-lys, jlb1-lys, and ΦJB-lys and their enzymatic domains (EADs) exhibited cell wall digestive activity and lytic activity against LAB. Jlb1-EAD and ΦJB-EAD were more sensitive than their respective hololysins to buffer pH and NaCl changes. The ΦJB-EAD exhibited stronger lytic activity than ΦJB-lys, possibly due to ΦJB-CBD-mediated sequestration of ΦJB-lys by cell debris. CBD multiplex assays indicate that these proteins may be useful LBP potency reagents, and the lytic activity suggests that CL1-lys, jlb1-lys, and ΦJB-lys and their EADs are good candidates for LBP purity reagent development.

Synthesizing Methuselah: The Question of Artificial Agelessness.

As biological organisms, we age and, eventually, die. However, age's deteriorating effects may not be universal. Some theoretical entities, due to their synthetic composition, could exist independently from aging-artificial general intelligence (AGI). With adequate resource access, an AGI could theoretically be ageless and would be, in some sense, immortal. Yet, this need not be inevitable. Designers could imbue AGIs with artificial mortality via an internal shut-off point. The question, though, is, should they? Should researchers curtail an AGI's potentially endless lifespan by deliberately making it mortal? It is this question that this article explores. First, it considers what type of AGI is under discussion before outlining how such beings could be ageless. Then, after clarifying the type of immortality under discussion and arguing that imbuing an AGI with synthetic aging would be person-affecting, the article explores four core conundrums: (i) deliberately causing a morally significant being's death; (ii) immortality's associated harms; (iii) concerns about immortality's unequal assignment; and (iv) the danger of immortal AGI overlords. The article concludes that while prudence requires we create an aging AGI, in the face of the material harm such an action would constitute, this is an insufficient reason to justify doing so.

Stoichiometric characteristics of woody plant leaves and responses to climate and soil factors in China.

The main research content of the field of ecological stoichiometry is the energy of various chemical elements and the interaction between organisms and the environment throughout ecological processes. Nitrogen and phosphorus are the main elements required for the growth and development of plants and these also form the constituent basis of biological organisms. Both elements interact and jointly regulate the growth and development of plants, and their element ratios are an indication of the nutrient utilization rate and nutrient limitation status of plants. Previous research developed a general biogeography model of the stoichiometric relationship between nitrogen and phosphorus in plant leaves on a global scale. Further, it was shown that the relative rate of nitrogen uptake by leaves was lower than that of phosphorus, and the scaling exponent of nitrogen and phosphorus was 2/3. However, it is not clear how the stoichiometric values of nitrogen and phosphorus, especially their scaling exponents, change in the leaves of Chinese woody plants in response to changing environmental conditions. Therefore, data sets of leaf nitrogen and phosphorus concentrations, and nitrogen to phosphorus ratios in Chinese woody plants were compiled and classified according to different life forms. The overall average concentrations of nitrogen and phosphorus in leaves were 20.77 ± 8.12 mg g-1 and 1.58 ± 1.00 mg g-1, respectively. The contents of nitrogen and phosphorus in leaves of deciduous plants were significantly higher than those of evergreen plants. In leaves, life form is the main driving factor of nitrogen content, and mean annual temperature is the main driving factor of phosphorus content; soil available nitrogen is the main driving factor of the nitrogen to phosphorus ratio. These values can be used for comparison with other studies. In addition, the scale index was found to be significantly different among different life forms. The scaling exponents of N-P of woody plants of different life forms, such as trees, shrubs, evergreen, deciduous, and coniferous plants are 0.67, 0.72, 0.63, 0.72, and 0.66, respectively. The N-P scaling exponent of shrubs was higher than that of trees, and that of deciduous plants was higher than that of evergreen plants. These results suggest that the internal attributes of different life forms, the growth rate related to phosphorus, and the relative nutrient availability of soil are the reasons for the unsteady relationship between nitrogen and phosphorus in leaves.

Stress granule-mediated RNA regulatory mechanism in Alzheimer's disease.

Living organisms experience a range of stresses. To cope effectively with these stresses, eukaryotic cells have evolved a sophisticated mechanism involving the formation of stress granules (SGs), which play a crucial role in protecting various types of RNA species under stress, such as mRNAs and long non-coding RNAs (lncRNAs). SGs are non-membranous cytoplasmic ribonucleoprotein (RNP) granules, and the RNAs they contain are translationally stalled. Importantly, SGs have been thought to contribute to the pathophysiology of neurodegenerative diseases, including Alzheimer's disease (AD). SGs also contain multiple RNA-binding proteins (RBPs), several of which have been implicated in AD progression. SGs are transient structures that dissipate after stress relief. However, the chronic stresses associated with aging lead to the persistent formation of SGs and subsequently to solid-like pathological SGs, which could impair cellular RNA metabolism and also act as a nidus for the aberrant aggregation of AD-associated proteins. In this paper, we provide a comprehensive summary of the physical basis of SG-enriched RNAs and SG-resident RBPs. We then review the characteristics of AD-associated gene transcripts and their similarity to the SG-enriched RNAs. Furthermore, we summarize and discuss the functional implications of SGs in neuronal RNA metabolism and the aberrant aggregation of AD-associated proteins mediated by SG-resident RBPs in the context of AD pathogenesis. Geriatr Gerontol Int 2024; 24: 7-14.

Dynamic Growth of Macroscopically Structured Supramolecular Hydrogels through Orchestrated Reaction-Diffusion.

Living organisms are capable of dynamically changing their structures for adaptive functions through sophisticated reaction-diffusion processes. Here we show how active supramolecular hydrogels with programmable lifetimes and macroscopic structures can be created by relying on a simple reaction-diffusion strategy. Two hydrogel precursors (poly(acrylic acid) PAA/CaCl2 and Na2 CO3 ) diffuse from different locations and generate amorphous calcium carbonate (ACC) nanoparticles at the diffusional fronts, leading to the formation of hydrogel structures driven by electrostatic interactions between PAA and ACC nanoparticles. Interestingly, the formed hydrogels are capable of autonomously disintegrating over time because of a delayed influx of electrostatic-interaction inhibitors (NaCl). The hydrogel growth process is well explained by a reaction-diffusion model which offers a theoretical means to program the dynamic growth of structured hydrogels. Furthermore, we demonstrate a conceptual access to dynamic information storage in soft materials using the developed reaction-diffusion strategy. This work may serve as a starting point for the development of life-like materials with adaptive structures and functionalities.

Electrolysis of Direct Seawater: Challenges, Strategies, and Future Prospects†

Comprehensive SummaryThe use of renewable sources such as solar, ocean, geothermal, and wind energy to drive water electrolysis reactions to obtain green and clean hydrogen fuels is one of the important paths to achieve sustainable energy development. At present, most water electrolysis technologies need to conduct corresponding pre‐processing, such as diluting water sources and purifying dehydration, which will greatly increase operating costs. The development of direct seawater electrolytic process can effectively solve the above problems. Here, we review the latest progress of the electrode materials and catalysts of the direct electrolysis process of seawater, and discuss how to design high activity and high‐selective electrode materials for water electrolysis with familiar impurities (such as chloride, metal ions and biological organisms) existing in the future.

Effects of membrane potentials on the electroporation of giant unilamellar vesicles.

Living organisms maintain a resting membrane potential, which plays an important role in various biophysical and biological processes. In the context of medical applications, irreversible electroporation (IRE) is a non-thermal and minimally invasive technique that utilizes precisely controlled electric field pulses of micro- to millisecond durations to effectively ablate cancer and tumor cells. Previous studies on IRE-induced rupture of cell-mimetic giant unilamellar vesicles (GUVs) have primarily been conducted in the absence of membrane potentials. In this study, we investigated the electroporation of GUVs, including parameters such as the rate constant of rupture and the probability of rupture, in the presence of various negative membrane potentials. The membranes of GUVs were prepared using lipids and channel forming proteins. As the membrane potential increased from 0 to -90 mV, the rate constant of rupture showed a significant increase from (7.5 ± 1.6)×10-3 to (35.6 ± 5.5)×10-3 s-1. The corresponding probability of rupture also exhibited a notable increase from 0.40 ± 0.05 to 0.68 ± 0.05. To estimate the pore edge tension, the electric tension-dependent logarithm of the rate constant was fitted with the Arrhenius equation for different membrane potentials. The presence of membrane potential did not lead to any significant changes in the pore edge tension. The increase in electroporation is reasonably explained by the decrease in the prepore free energy barrier. The choice of buffer used in GUVs can significantly influence the kinetics of electroporation. This study provides valuable insights that can contribute to the application of electroporation techniques in the biomedical field.

Construction of a ratiometric fluorescent probe for discriminative detection of SO2 derivatives and Cys and its bio-imaging application

Endogenous sulfur dioxide (SO2) and cysteine (Cys) are important species and interacted with each other. However, due to the reactivity of these species, it is difficult to differentiated detection them. Thus, it is necessary to develop new fluorescent probe for discriminative detect these reactive sulfur species in biological environment. Herein, A new hemicyanine derivative Mito-AE with dual recognition sites for SO2 derivatives and Cys detection was constructed and applied in biological detection. Mito-AE exhibited ratiometric fluorescence change (F470/F610) of over 90-fold when interacted with SO2, and a dramatic fluorescence turn-on at 610 nm when interacted with Cys. The probe can monitor both SO2 derivatives and Cys with fast response rate (within 1 min), high sensitivity and selectivity. As proved by biological experiments, Mito-AE was able to successfully detect exogenous and endogenous SO2 in living cells as well as in mitochondria area. More importantly, the detection of SO2 derivatives and Cys in zebrafish model suggesting a potential application for studying the multiple interaction of biological sulfurous species in live organism.

Understanding the mechanism of red light-induced melatonin biosynthesis facilitates the engineering of melatonin-enriched tomatoes

Melatonin is a functionally conserved broad-spectrum physiological regulator found in most biological organisms in nature. Enrichment of tomato fruit with melatonin not only enhances its agronomic traits but also provides extra health benefits. In this study, we elucidate the full melatonin biosynthesis pathway in tomato fruit by identifying biosynthesis-related genes that encode caffeic acid O-methyltransferase 2 (SlCOMT2) and N-acetyl-5-hydroxytryptamine-methyltransferases 5/7 (SlASMT5/7). We further reveal that red light supplementation significantly enhances the melatonin content in tomato fruit. This induction relies on the “serotonin—N-acetylserotonin—melatonin” biosynthesis route via the SlphyB2-SlPIF4-SlCOMT2 module. Based on the regulatory mechanism, we design a gene-editing strategy to target the binding motif of SlPIF4 in the promoter of SlCOMT2, which significantly enhances the production of melatonin in tomato fruit. Our study provides a good example of how the understanding of plant metabolic pathways responding to environmental factors can guide the engineering of health-promoting foods.