Metabolome evidence of CKDu risks after chronic exposure to simulated Sri Lanka drinking water in zebrafish.

It is still a serious public health issue that chronic kidney disease of uncertain etiology (CKDu) in Sri Lanka poses challenges in identification, prevention, and treatment. What environmental factors in drinking water cause kidney damage remains unclear. This study aimed to investigate the risks of various environmental factors that may induce CKDu, including water hardness, fluoride (HF), heavy metals (HM), microcystin-LR (MC-LR), and their combined exposure (HFMM). The research focused on comprehensive metabolome analysis, and correlation with transcriptomic and gut microbiota changes. Results revealed that chronic exposure led to kidney damage and pancreatic toxicity in adult zebrafish. Metabolomics profiling showed significant alterations in biochemical processes, with enriched metabolic pathways of oxidative phosphorylation, folate biosynthesis, arachidonic acid metabolism, FoxO signaling pathway, lysosome, pyruvate metabolism, and purine metabolism. The network analysis revealed significant changes in metabolites associated with renal function and diseases, including 20-Hydroxy-LTE4, PS(18:0/22:2(13Z,16Z)), Neuromedin N, 20-Oxo-Leukotriene E4, and phenol sulfate, which are involved in the fatty acyls and glycerophospholipids class. These metabolites were closely associated with the disrupted gut bacteria of g_ZOR0006, g_Pseudomonas, g_Tsukamurella, g_Cetobacterium, g_Flavobacterium, which belonged to dominant phyla of Firmicutes and Proteobacteria, etc., and differentially expressed genes (DEGs) such as egln3, ca2, jun, slc2a1b, and gls2b in zebrafish. Exploratory omics analyses revealed the shared significantly changed pathways in transcriptome and metabolome like calcium signaling and necroptosis, suggesting potential biomarkers for assessing kidney disease.

[Identification of chemical components in Qinggu San reference sample of classial prescription based on UHPLC-Q/Orbitrap HRMS combined with molecular network technology].

The method of ultra-high performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry(UHPLC-Q/Orbitrap HRMS)combined with molecular network was developed in this study for rapidly analyzing the chemical components of the Qinggu San reference sample of classical prescription. Firstly, an ACQUITY UPLC BEH Shield RP_(18) column(2.1 mm×100 mm, 1.7 µm)was used, and acetonitrile and 0.1% formic acid were taken as the mobile phases for gradient elution. The flow rate was 0.4 mL·min~(-1), and the column temperature was 30 ℃. Under these conditions, the mass spectrum data were collected in both positive and negative ion modes of the heated electrospray ionization source. Subsequently, the mass spectrum data of the Qinggu San reference sample were uploaded to the Global Natural Products Social Molecular Network(GNPS)platform for calculation and analysis, and a visual molecular network was built with Cytoscape 3.8.2 software. On this basis, the chemical components of the Qinggu San reference sample were identified by fragmentation regularity of standard compounds, retention time, accurate relative molecular weight of HR-MS, characteristic fragment ions information, literature, and databases. Finally, a total of 105 chemical components were identified and speculated in the Qinggu San reference sample, including 19 iridoid glycosides, 23 flavonoids, 15 phenylpropanoids, 11 triterpene saponins, and 37 other components. Meanwhile, two of these components are potential new compounds. The method used in this study not only achieved rapid and accurate identification of chemical components in the Qinggu San reference sample and provided a scie-ntific basis for the study of pharmacological substances and quality control of Qinggu San compound preparations but also provided a refe-rence for the rapid identification of chemical components in traditional Chinese medicine compound preparations.

mitfa deficiency promotes immune vigor and potentiates antitumor effects in zebrafish.

The mitfa gene is a well-known transcription factor associated with microphthalmia and is essential for early melanophore development. However, little is known about how mitfa affects the immune system. Here, we generated a novel mitfa knock-out zebrafish line using the CRISPR/Cas9 system. The mitfa-/- zebrafish exhibited reduced melanin levels compared to the nacre mutant. We investigated the impact on the immune system after exposure to Edwardsiella tarda and bifenazate in zebrafish larvae, and observed that the macrophage numbers were reduced in both treated groups. Remarkably, the expression levels of immune-related genes exhibited significant increases after bacterial challenge or bifenazate exposure in the mitfa-/- zebrafish, except for tlr4 and rela. Furthermore, we conducted xenograft experiments using mouse B16 melanoma cells. Notably, the cancer cells didn't show a high cell migration ratio, implying that the immune system was highly activated after the loss of mifta. Taken together, our findings suggest that mitfa-/- zebrafish serve as a valuable model for investigating the relationship between the immune system and melanocytes, providing new insights into the role of mitfa in immune responses.

Bacteriophage-based techniques for elucidating the function of zebrafish gut microbiota.

Bacteriophages (or phages) are unique viruses that can specifically infect bacteria. Since their discovery by Twort and d'Herelle, phages with bacterial specificity have played important roles in microbial regulation. The intestinal microbiota and host health are intimately linked with nutrient, metabolism, development, and immunity aspects. However, the mechanism of interactions between the composition of the microbiota and their functions in maintaining host health still needs to be further explored. To address the lack of methodology and functions of intestinal microbiota in the host, we first proposed that, with the regulations of special intestinal microbiota and applications of germ-free (GF) zebrafish model, phages would be used to infect and reduce/eliminate the defined gut bacteria in the conventionally raised (CR) zebrafish and compared with the GF zebrafish colonized with defined bacterial strains. Thus, this review highlighted the background and roles of phages and their functional characteristics, and we also summarized the phage-specific infection of target microorganisms, methods to improve the phage specificity, and their regulation within the zebrafish model and gut microbial functional study. Moreover, the primary protocol of phage therapy to control the intestinal microbiota in zebrafish models from larvae to adults was recommended including phage screening from natural sources, identification of host ranges, and experimental design in the animal. A well understanding of the interaction and mechanism between phages and gut bacteria in the host can potentially provide powerful strategies or techniques for preventing bacteria-related human diseases by precisely regulating in vitro and in vivo, which will provide novel insights for phages' application and combined research in the future. KEY POINTS: • Zebrafish models for clarifying the microbial and phages' functions were discussed • Phages infect host bacteria with exquisite specificity and efficacy • Phages can reduce/eliminate the defined gut bacteria to clarify their function.

Ion Separation Together with Water Purification via a New Type of Nanotube: A Molecular Dynamics Study.

We propose a CNT-based concentric twin tube (CTT) as nanochannels for both water purification and ion separation at the nanoscale. In the model, a source reservoir dealing with the solution connects three containers via the CTT that has three subchannels for mass transfer. Before entering the three subchannels, the solution in the separating zone will form three layers (the aqua cations, water, and the aqua anions, respectively) by applying a charged capacitor with the two electrodes parallel to the flow direction of the solution. Under an electric field with moderate intensity, the three subchannels in the CTT have stable configurations for mass transfer. Since the water and the two types of aqua ions are collected by three different containers, the present model can realize both ion separation and water purification. The mass transfer in the subchannels will be sped up by an external pressure exerted on the solution in the source reservoir. The physical properties of the model, e.g., water purification speed, are analyzed with respect to the effects of the electric field, the size of CTT, and the concentration of solute, such as NaCl.

Photochromic Azobenzene Inverse Opal Film toward Dynamic Anti-Fake Pattern.

Azobenzene mesogens have garnered considerable research attention in the realm of photo-responsive materials due to their reversible trans-cis isomerization. In this paper, we demonstrate an azobenzene inverse opal film synthesized via photo-polymerization from a SiO2 opal template. The proposed design exhibits intriguing optical properties, including dynamic fluorescent features, distinct fluorescent enhancement, and an anti-fake micropattern with a switchable structure color. This work holds significant importance for advancing the development of novel optical devices.

In Situ Observation of Lysosomal Hypobromous Acid Fluctuations in the Brain of Mice with Depression Phenotypes by Two-Photon Fluorescence Imaging.

Excessive oxidative stress is the main cause of neurotransmitter metabolism disorder in the brain with depression. Lysosomal hypobromic acid (HOBr) is an important reactive oxygen species produced in oxidative stress. Its abnormal content can lead to macromolecular damage and neurodegenerative diseases. However, due to the high reactivity and low concentration of HOBr and the lack of in situ imaging methods, the role of HOBr in depression is not clear. Herein, based on the HOBr-initiated aromatic substitution of a tertiary amine, we developed a novel two-photon (TP) fluorescence probe (NH-HOBr) for real-time visual monitoring of trace HOBr in living systems. NH-HOBr introduces N-(2-aminoethyl)-morpholine as a new recognition receptor for HOBr and a targeting group for lysosomes. It not only has excellent selectivity compared with other biomolecules (including hypochlorous acid), fast response (≤5 s) and high sensitivity (LOD = 15 nM) but also realizes sensitive detection of HOBr in cells, zebrafish, and mice tissues. It is worth noting that the in situ TP fluorescence imaging of mouse brain reveals the positive correlation between HOBr content and depression phenotype for the first time, providing strong direct evidence for the relationship between oxidative stress and depression. This work can provide reference to further study depression and the pathological mechanism of HOBr. In addition, HOBr-initiated aromatic substitution of a tertiary amine provides a new idea for the construction of specific and sensitive HOBr probes.

Rayleigh-Plateau Instability of a Particle-Laden Liquid Column: A Lattice Boltzmann Study.

Colloidal particles known to be capable of stabilizing fluid-fluid interfaces have been widely applied in emulsion preparation, but their precise role and underlying influencing mechanism remain poorly understood. In this study, a perturbed liquid column with particles evenly distributed on its surface is investigated using a three-dimensional lattice Boltzmann method, which is built upon the color-gradient two-phase flow model but with a new capillary force model and a momentum exchange method for particle dynamics. The developed method is first validated by simulating the wetting behavior of a particle on a fluid interface and the classic Rayleigh-Plateau instability and is then used to explore the effects of particle concentration and contact angle on the capillary instability of the particle-laden liquid column. It is found that increasing the particle concentration can enhance the stability of the liquid column and thus delay the breakup, and the liquid column is most stable under slightly hydrophobic conditions, which corresponds to the lowest initial liquid-gas interfacial free energy. Due to different pressure gradients inside and outside the liquid column and the capillary force being directed away from the neck, hydrophobic particles tend to assemble in a less compact manner near the neck of the deformed liquid column, while hydrophilic particles prefer to gather far away from the neck. For hydrophobic particles, in addition to the influence of the initial liquid-gas interfacial free energy, the self-assembly of particles in a direction opposite to the liquid flow also contributes to opposing the rupture of the liquid column.

The Combination of 2D Layered Graphene Oxide and 3D Porous Cellulose Heterogeneous Membranes for Nanofluidic Osmotic Power Generation.

Salinity gradient energy, as a type of blue energy, is a promising sustainable energy source. Its energy conversion efficiency is significantly determined by the selective membranes. Recently, nanofluidic membrane made by two-dimensional (2D) nanomaterials (e.g., graphene) with densely packed nanochannels has been considered as a high-efficient membrane in the osmotic power generation research field. Herein, the graphene oxide-cellulose acetate (GO-CA) heterogeneous membrane was assembled by combining a porous CA membrane and a layered GO membrane; the combination of 2D nanochannels and 3D porous structures make it show high surface-charge-governed property and excellent ion transport stability, resulting in an efficient osmotic power harvesting. A power density of about 0.13 W/m2 is achieved for the sea-river mimicking system and up to 0.55 W/m2 at a 500-fold salinity gradient. With different functions, the CA and GO membranes served as ion storage layer and ion selection layer, respectively. The GO-CA heterogeneous membrane open a promising avenue for fabrication of porous and layered platform for wide potential applications, such as sustainable power generation, water purification, and seawater desalination.

Rational Design of a Targetable Fluorescent Probe for Visualizing H2S Production under Golgi Stress Response Elicited by Monensin.

As a eukaryotic organelle, the Golgi apparatus plays an essential role in various physiological activities such as stress response. The Golgi stress response is an important physiological process of conferring cytoprotection by regulating the synthesis and metabolism of bioactive molecules. Therefore, the development of new suitable in situ analytical techniques for monitoring related small molecular substances in the stress reaction of the Golgi apparatus is very helpful for further study of the regulatory mechanism of the Golgi apparatus. Recent studies have shown that endogenous hydrogen sulfide (H2S) also possesses crucial bioregulatory and protective performances in the stress response. Therefore, the high-fidelity in situ mapping of H2S production under the Golgi stress response plays an important role not only in revealing cytoprotection functions of H2S in the stress response but also in further understanding the regulatory mechanism of the Golgi stress response. In this work, we designed a simple Golgi-targetable H2S fluorescent probe (Gol-H2S) that responds accurately and sensitively to H2S in the Golgi apparatus of living cells and zebrafish. On the basis of its superior bioimaging performances, probe Gol-H2S was successfully applied to the in situ visualization of H2S production under the Golgi stress response elicited by monensin, a specific-Golgi stressor. The related process of the Golgi stress response was validated by stimulation and inhibition experiments. These findings fully demonstrate that H2S is an alternative biomarker of the Golgi stress response. Moreover, probe Gol-H2S can also be used as a potential tool for disclosing the detailed H2S-cytoprotection mechanisms under the regulation of the Golgi stress response in related diseases.

Gut bacteria Vibrio sp. and Aeromonas sp. trigger the expression levels of proinflammatory cytokine: First evidence from the germ-free zebrafish.

Gut microbiota plays a central part in the regulation of multiple host metabolic pathways, such as homeostasis, immunostasis, mucosa permeability, and even brain development. Though, slight known about the function of an individual gut bacterium in zebrafish. In this study, germ-free (GF) and conventionally reared (CV) zebrafish models utilized for studying the role of gut bacteria Vibrio sp. and Aeromonas sp. After the analysis of gut microbial profile in zebrafish male and female at three-month age, Proteobacteria and Fusobacteria dominated the main composition of zebrafish intestinal microflora. However, the relative richness of them was different base on gender variance. Aeromonas sp. and Vibrio sp. belonging to Proteobacteria phylum of bacteria were isolated from zebrafish gut, and their potential capacities to trigger innate immunity were investigated. In gut microbiota absence, the expression levels of the innate immunity genes in the GF group were not significantly changed compared to the CV group. After exposure to Aeromonas sp. and Vibrio sp., the expression levels of myd88, TLRs-, and inflammation-related genes were increased in both GF and CV groups, except tlr2 and NLRs-related genes. However, the expression level of NF-κB and JNK/AP-1 pathway genes were all decreased after exposure to Aeromonas sp. and Vibrio sp. in both GF and CV groups. Interestingly, inflammation-related genes (tnfa, tnfb, and il1ß) were activated in the CV group, and there were not significantly changed in the GF group, indicating that other bacteria were indispensable for Aeromonas sp. or Vibrio sp. to activate the inflammation response. Taken together, this is the first study of gut bacteria Vibrio sp. and Aeromonas sp. prompting the innate immune response using the GF and CV zebrafish model.

Giant ripples on comet 67P/Churyumov-Gerasimenko sculpted by sunset thermal wind.

Explaining the unexpected presence of dune-like patterns at the surface of the comet 67P/Churyumov-Gerasimenko requires conceptual and quantitative advances in the understanding of surface and outgassing processes. We show here that vapor flow emitted by the comet around its perihelion spreads laterally in a surface layer, due to the strong pressure difference between zones illuminated by sunlight and those in shadow. For such thermal winds to be dense enough to transport grains-10 times greater than previous estimates-outgassing must take place through a surface porous granular layer, and that layer must be composed of grains whose roughness lowers cohesion consistently with contact mechanics. The linear stability analysis of the problem, entirely tested against laboratory experiments, quantitatively predicts the emergence of bedforms in the observed wavelength range and their propagation at the scale of a comet revolution. Although generated by a rarefied atmosphere, they are paradoxically analogous to ripples emerging on granular beds submitted to viscous shear flows. This quantitative agreement shows that our understanding of the coupling between hydrodynamics and sediment transport is able to account for bedform emergence in extreme conditions and provides a reliable tool to predict the erosion and accretion processes controlling the evolution of small solar system bodies.

A coumarin-based fluorescent probe for Hg2+ and its application in living cells and zebrafish.

Mercury (Hg) is a heavy metal with high toxicity and easy migration; it can be enriched through the food chain, and cause serious threats to the natural environment and human health. So, the development of a method that can be used to detect mercury ions (Hg2+ ) in the environment, in cells, and in organisms is very important. Here, a new 7-hydroxycoumarin-derived carbonothioate-based probe (CC-Hg) was designed and synthesized for detection of Hg2+ . After addition of Hg2+ , a large fluorescence enhancement was observed due to the formation of 7-hydroxyl, which reinforced the intramolecular charge transfer process. The CC-Hg probe had good water solubility and selectivity. Moreover, the probe was able to detect Hg2+ quantitatively over the concentration range 0-2 µM and with a detection limit of 7.9 nM. Importantly, we successfully applied the probe to detect Hg2+ in water samples, in living cells, and in zebrafish. The experimental results demonstrated its potential value in practical applications.

Rational Design of a Hepatoma-Specific Fluorescent Probe for HOCl and Its Bioimaging Applications in Living HepG2 Cells.

Liver cancer is a kind of high mortality cancer due to the difficulty of early diagnosis. And according to the reports, the concentration of reactive oxygen species (ROS) was higher in cancer cells than normal cells. Therefore, developing an effective fluorescent probe for hepatoma-selective imaging of hypochlorous acid (HOCl) which is one of the vital ROS is of great importance for understanding the role of HOCl in liver cancer pathogenesis. However, the cell-selective fluorescent probe still remains a difficult task among current reports. Herein, a galactose-appended naphthalimide (Gal-NPA) with p-aminophenylether as a new receptor and galactose moiety as hepatoma targeting unit was synthesized and employed to detect endogenous HOCl in living HepG2 cells. This probe was proved to possess good water solubility and could respond specifically to HOCl. In addition, probe Gal-NPA could completely react to HOCl within 3 s meanwhile accompanied by tremendous fluorescence enhancement. The quantitative linear range between fluorescence intensities and the HOCl concentrations was 0 to 1 µM (detection limit = 0.46 nM). More importantly, fluorescence confocal imaging experiments showed that probe Gal-NPA could discriminate hepatoma cells over other cancer cells and simultaneously trace endogenous HOCl levels in living HepG2 cells. And we thus anticipate that probe Gal-NPA has the potential application for revealing the functions of HOCl in hepatoma cells.

Highly Efficient Ionic Photocurrent Generation through WS2 -Based 2D Nanofluidic Channels.

The unique feature of nacre-like 2D layered materials provides a facile, yet highly efficient way to modulate the transmembrane ion transport from two orthogonal transport directions, either vertical or horizontal. Recently, light-driven active transport of ionic species in synthetic nanofluidic systems attracts broad research interest. Herein, taking advantage of the photoelectric semiconducting properties of 2D transition metal dichalcogenides, the generation of a directional and greatly enhanced cationic flow through WS2 -based 2D nanofluidic membranes upon asymmetric visible light illumination is reported. Compared with graphene-based materials, the magnitude of the ionic photocurrent can be enhanced by tens of times, and its photo-responsiveness can be 2-3.5 times faster. This enhancement is explained by the coexistence of semiconducting and metallic WS2 nanosheets in the hybrid membrane that facilitates the asymmetric diffusion of photoexcited charge carriers on the channel wall, and the high ionic conductance due to the neat membrane structure. To further demonstrate its application, photonic ion switches, photonic ion diodes, and photonic ion transistors as the fundamental elements for light-controlled nanofluidic circuits are further developed. Exploring new possibilities in the family of liquid processable colloidal 2D materials provides a way toward high-performance light-harvesting nanofluidic systems for artificial photosynthesis and sunlight-driven desalination.

A long-wavelength ultrasensitive colorimetric fluorescent probe for carbon monoxide detection in living cells.

Exploring techniques for monitoring the intracellular signaling molecule carbon monoxide (CO) in biosystems is important to help understand its various cellular functions. Therefore, a simple long-wavelength colorimetric fluorescent probe LW-CO was designed for selectively and sensitively detecting intracellular CO in living systems. Probe LW-CO is ultrasensitive and can track CO levels in the range of 0-1 µM, with a detection limit of about 3.2 nM. Additionally, the obvious color changes of probe LW-CO with CO (yellow to pink) provide a convenient way for on-site detection of CO with the naked eye. Probe LW-CO was applied to track the exogenous levels of CO in RAW264.7 cells. Probe LW-CO proved to be an efficient method for investigating various cellular functions of CO.

A novel water-soluble fluorescent probe with ultra-sensitivity over a wider pH range and its application for differentiating cancer cells from normal cells.

A novel pH-sensitive fluorescent probe has been designed and synthesized for sensing intracellular pH. This probe showed excellent water solubility, it was sensitive toward the pH range from 4 to 12, and it was especially sensitive in alkaline environments. During the pH changes from acidic to alkaline environments, the color of the solution turned from yellow to purple, thus the difference in color can be used to distinguish between acidic and alkaline systems. The other major features of probe pH-DCN including high selectivity, low toxicity, good reversibility and stability allowed pH-DCN to visualize fluctuations of the pH in live cells. Moreover, probe pH-DCN has successfully discriminated cancer cells from normal cells by monitoring their different intracellular pH levels.

A novel highly sensitive fluorescent probe for bioimaging biothiols and its applications in distinguishing cancer cells from normal cells.

In recent years, targeting drugs made by physical loading or chemical bonding of drugs on small molecular carriers have shown a very wide application prospect in the field of tumor and cancer treatment. How to achieve the release of drugs in cancer cells has become the core of this research. One of the most important bases for drug localization is to use the difference of small molecular biothiol concentration between cancer cells and normal cells. Details of the changes of biothiol levels in the growth and reproduction of cancer cells are still poorly understood, and the main reason is the lack of sensitive real-time imaging tools for biothiols in cancer cells. In this work, we reasonably designed and synthesized the combination of 4-hydroxy-1,8-naphthalimide and NBD-Cl as a concise fluorescent probe HN-NBD for imaging biothiols in live cells and zebrafish. In addition, due to the advantages of HN-NBD design, it is sufficiently sensitive to biothiols, and further imaging can distinguish cancer cells from normal cells. Probe HN-NBD would be of great significance to biomedical researchers for the study of biothiol-related diseases, the screening of new anticancer drugs, and the early diagnosis and treatment of cancers.

A highly selective and sensitive red-emitting fluorescent probe for visualization of endogenous peroxynitrite in living cells and zebrafish.

Peroxynitrite (ONOO-) has been proven to participate in various physiological and pathological processes, and may also be a contributing factor in many diseases. In view of this, there is a need to develop detection tools for unambiguously tracking a small amount of endogenous ONOO- to reveal its exact mechanisms. In this paper, a colorimetric and red-emitting fluorescent probe Red-PN, based on a rhodamine-type fluorophore and hydrazide reactive site is described. The probe Red-PN possesses the advantages of rapid response (within 5 s), visual color change (from colorless to pink), preeminent sensitivity (detection limit = 4.3 nM) and selectivity. Because of these outstanding performances, it was possible to accurately detect endogenous ONOO-. It was encouraging that the probe Red-PN could be used effectively for tracking the relatively low levels of endogenous and exogenous ONOO- in living cells and zebrafish. Thus, it is envisioned that the probe Red-PN would have promising prospects in applications for imaging ONOO- in a variety of biological settings.

A carbonothioate-based far-red fluorescent probe for the specific detection of mercury ions in living cells and zebrafish.

The detection of ionic mercury (Hg2+) is very important because it is a highly toxic environmental pollutant that could cause serious diseases and threaten human health. Herein, we designed a new carbonothioate-based far-red fluorescent probe, CBRB, with a seminaphthorhodafluor dye as the fluorophore for the detection of Hg2+. The CBRB probe by itself exhibited very weak fluorescence due to the enhanced photo-induced electron transfer (PET) effect and inhibited the intramolecular charge transfer (ICT) process caused by the carbonothioate moiety. Upon addition of Hg2+, a tremendous fluorescence enhancement was achieved, attributed to the removal of the carbonothioate group via a specific mercury-promoted desulfurization reaction. Moreover, the probe displayed a large Stokes shift (about 105 nm) and was used to quantitatively measure the concentration of Hg2+ for concentrations ranging from 0 to 1 µM (DL = 3.6 nM). In addition, CBRB in our experiments responded exclusively to Hg2+, even in the presence of high concentrations other ions. Gratifyingly, this probe was successfully used to monitor Hg2+ in environmental water samples and to image Hg2+ in living cells as well as in zebrafish.