Anaerobic membrane bioreactors for municipal wastewater: Progress in resource and energy recovery improvement approaches.

Anaerobic membrane bioreactor (AnMBR) offer promise in municipal wastewater treatment, with potential benefits including high-quality effluent, energy recovery, sludge reduction, and mitigating greenhouse gas emissions. However, AnMBR face hurdles like membrane fouling, low energy recovery, etc. In light of net-zero carbon target and circular economy strategy, this work sought to evaluate novel AnMBR configurations, focusing on performance, fouling mitigation, net-energy generation, and nutrients-enhancing integrated configurations, such as forward osmosis (FO), membrane distillation (MD), bioelectrochemical systems (BES), membrane photobioreactor (MPBR), and partial nitrification-anammox (PN/A). In addition, we highlight the essential role of AnMBR in advancing the circular economy and propose ideas for the water-energy-climate nexus. While AnMBR has made significant progress, challenges, such as fouling and cost-effectiveness persist. Overall, the use of novel configurations and energy recovery strategies can further improve the sustainability and efficiency of AnMBR systems, making them a promising technology for future sustainable municipal wastewater treatment.

The ghrelin receptor GHSR has two efficient agonists in the lobe-finned fish Latimeria chalumnae.

The peptide hormone ghrelin (an agonist) and LEAP2 (an antagonist) play important functions in energy metabolism via their receptor GHSR, an A-class G protein-coupled receptor. Ghrelin, LEAP2, and GHSR are widely present from fishes to mammals. However, our recent study suggested that fish GHSRs have different binding properties to ghrelin: a GHSR from the lobe-finned fish Latimeria chalumnae (coelacanth) is efficiently activated by ghrelin, but GHSRs from the ray-finned fish Danio rerio (zebrafish) and Larimichthys crocea (large yellow croaker) have lost binding to ghrelin. Do fish GHSRs use another peptide as their agonist? In the present study we tested to two fish motilins from D. rerio and L. chalumnae because motilin is distantly related to ghrelin. In ligand binding and activation assays, the fish GHSRs from D. rerio and L. crocea displayed no detectable or very low binding to all tested motilins; however, the fish GHSR from L. chalumnae bound to its motilin with high affinity and was efficiently activated by it. Therefore, it seemed that motilin is not a ligand for GHSR in the ray-finned fish D. rerio and L. crocea, but is an efficient agonist for GHSR in the lobe-finned fish L. chalumnae, one of the closest fish relatives of tetrapods. The results of present study suggested that GHSR might have two efficient agonists, ghrelin and motilin, in ancient fishes; however, this feature might be only preserved in some extant fishes with ancient evolutionary origins.

Nanomolar range of FAM237B can activate receptor GPR83.

Our recent study confirmed that the mature neuropeptide FAM237A, also known as neurosecretory protein GL (NPGL), is an efficient agonist for GPR83. The paralog FAM237B was previously reported as a weak agonist for GPR83. In the present study, we prepared mature human FAM237B via an intein-fusion approach and demonstrated that it could cause a significant activation effect at the nanomolar range (1‒10 nM) in a NanoBiT-based ß-arrestin recruitment assay. Thus, FAM237B appears to be another endogenous agonist for GPR83 and future in vivo studies will be required to confirm this.

Ambient ultrafine particle (PM0.1): Sources, characteristics, measurements and exposure implications on human health.

The problem of ultrafine particles (UFPs; PM0.1) has been prevalent since the past decades. In addition to become easily inhaled by human respiratory system due to their ultrafine diameter (<100 nm), ambient UFPs possess various physicochemical properties which make it more toxic. These properties vary based on the emission source profile. The current development of UFPs studies is hindered by the problem of expensive instruments and the inexistence of standardized measurement method. This review provides detailed insights on ambient UFPs sources, physicochemical properties, measurements, and estimation models development. Implications on health impacts due to short-term and long-term exposure of ambient UFPs are also presented alongside the development progress of potentially low-cost UFPs sensors which can be used for future UFPs studies references. Current challenge and future outlook of ambient UFPs research are also discussed in this review. Based on the review results, ambient UFPs may originate from primary and secondary sources which include anthropogenic and natural activities. In addition to that, it is confirmed from various chemical content analysis that UFPs carry heavy metals, PAHs, BCs which are toxic in its nature. Measurement of ambient UFPs may be performed through stationary and mobile methods for environmental profiling and exposure assessment purposes. UFPs PNC estimation model (LUR) developed from measurement data could be deployed to support future epidemiological study of ambient UFPs. Low-cost sensors such as bipolar ion and ionization sensor from common smoke detector device may be further developed as affordable instrument to monitor ambient UFPs. Recent studies indicate that short-term exposure of UFPs can be associated with HRV change and increased cardiopulmonary effects. On the other hand, long-term UFPs exposure have positive association with COPD, CVD, CHF, pre-term birth, asthma, and also acute myocardial infarction cases.

A review on vitrification technologies of hazardous waste.

Vitrification technology provides a solution for the issue of safe disposal of hazardous waste containing harmful chemical composition and organic pollutants. This review discusses application of vitrification technologies to treat hazardous waste including, asbestos, fly ash, electronic sludge, nuclear waste, medical waste and radioactive waste. Vitrification processes via Joule heating, microwave heating, plasma technology, electric arc furnaces and incinerators are compared herein. Stabilization of hazardous waste can be achieved by vitrification with the addition of flux agents/additives. Furthermore, crystalline structures, containing the silicate-glass network, are formed as a result of vitrification, depending on the type of flux agents/additives used. In addition, the concentration of heavy metals can be degraded in the final residue and leaching resistance can be achieved. Moreover, energy consumption, pollution prevention and the foreground of the practical application of vitrification are discussed. Vitrification with the advantage of encapsulating pollutants from the hazardous waste is proven to be a promising approach for hazardous waste treatment.

Application of plasma technology for treating e-waste: A review.

This review details the current information on e-waste treatment using plasma technology. The current status of e-waste treatment via plasma technology from the scientific literature is presented herein, namely, moist paste battery, galvanic sludge, resin, printed circuit board, and semiconductor industries. The concept of plasma technology, classification of e-waste, contaminants of e-waste (metals, metalloids, and VOCs), and vitrification of the final product are presented herein. This review paper focuses on fusing flux agents to vitrify e-waste. Furthermore, this paper covers laboratory-scale investigations, plasma technology benefits, and reuse of material from plasma post-treatment. The use of plasma technology combined with flux agents could be recommended to eliminate contaminants from e-waste. Materials from plasma post-treatment may also be applied in environmental reuse applications.

Economic and environmental evaluation of flux agents in the vitrification of resin waste: A SWOT analysis.

Flux agents play an important role in the pyrolysis treatment of vitrifying hazardous wastes. Among these is plasma jets, a cost-less flux agent derived from shell powder which can be used to create vitrification. It is a promising option to be applied in the vitrification of elements and to remove the VOCs of hazardous waste, namely, resin from PCB scrap in an atmospheric-pressure microwave plasma reactor. In this study, a laboratory scale experiment was conducted. The experiment was performed in the pyrolysis of resin which was added with flux agents. The economic evaluation of the flux agents, and the circular economy concept of the final residue derived from the plasma pyrolysis was then analyzed post treatment. To test the strength and weakness of the experiment, the SWOT analysis was performed. The outcome helped in the understanding of the cost-less flux agent used in the pyrolysis treatment of hazardous waste. Results showed that fusing shell powder in resin was better for improving the removal efficiency of VOCs, such as benzene and toluene as well as toxic metals than compared to other flux agents such as limestone and quartz sand. Moreover, the final residue of resin was found to fulfil the concept of circular economy where it could be reused as an absorbent of methyl blue, thereby indicating good absorption performance, from 1 ppm-100 ppm. The twelve strategies that were derived from the SWOT analysis could be used as information outlining the current internal and external condition for the development and application of shell powder. Shell powder, as a cost-less flux agent, has the potential for enhancing waste management and circular economy when used in the pyrolysis treatment of future hazardous wastes.

Translation and Psychometric Analysis of the Chinese Version of the Dutch Eating Behavior Questionnaire for Children (DEBQ-C) in Taiwanese Preadolescents.

PURPOSE: This study aimed to translate and evaluate the psychometric properties of a Chinese version of the (DEBQ-C) among Taiwanese preadolescents. DESIGN AND METHODS: The DEBQ-C was translated into Mandarin Chinese (CDEBQ-C) using established translation and back-translation methods and reviewed by an expert panel for cultural equivalence. A convenience sample of 349 preadolescents was randomly split to conduct exploratory factor analysis (EFA) on the first half and confirmatory factor analysis (CFA) on the second. Internal consistency estimates for subscales were evaluated using Cronbach's alpha. Construct validation with academic stress, a theoretically related construct, was also examined. RESULTS: The theoretical dimensions of the original DEBQ-C were supported with an EFA that revealed the presence of three factors with 41.23% variance explained, and model fit was confirmed by CFA. Construct validation was supported by positive correlations with academic stress. Each subscale of the CDEBQ-C demonstrated satisfactory internal consistency (Cronbach's alpha = 0.72-0.86). Overweight/obese preadolescents scored significantly higher on restrained eating compared to other weight groups. CONCLUSIONS: The findings suggest that the CDEBQ-C is a psychometrically valid and reliable instrument for assessing overeating tendencies with Taiwanese preadolescents. Replication studies with greater diversity in age, ethnicity, and weight are needed to provide further evidence of construct validity for the CDEBQ-C. PRACTICE IMPLICATIONS: Clinicians and researchers can use the CDEBQ-C to assess or expand the knowledge of children's overeating. At-risk preadolescents can be identified at an early stage and effective and individualized intervention programs may be designed and facilitated.

Exploring Cultural Health Practices at a Midwestern University.

This study investigated complementary health practices (CHPs) at a Midwestern state university to examine regional usage rates. Study results demonstrated a high use of CHPs as compared with national studies, supporting significance of incorporating CHPs in the nursing curriculum to ensure culturally competent and safe care for all populations.

Extrarenal Wilms' Tumor of the Female Genital System: A Case Report and Literature Review.

Extrarenal Wilms' Tumors (ERWTs) are rare. There have been only 25 cases of ERWT arising from the female genital system reported in the literature. In this paper, we report a 60-year-old woman with a complaint of vaginal bleeding and a polypoid mass in the uterine cavity by sonography that was demonstrated as ERWT by pathology after resection. The pathological characteristics, histological origination, diagnosis, therapy and prognosis of ERWT in female reproductive system are discussed in this paper in the purpose of improving the diagnosis and therapy of this rare tumor.

Psychometric Properties of the Chinese Version of the Children's Resourcefulness Scale in Taiwanese Children.

This study reports the psychometric properties of a Chinese version of the Children's Resourcefulness Scale (C-CRS) for Taiwanese children. An instrument for assessing resourcefulness skills in children and adolescents, the CRS was translated into Mandarin Chinese, and a cross-sectional investigation was conducted with a convenience sample of 368 fifth and sixth graders recruited from three geographically diverse locations in Taiwan. Internal consistency statistics from the total sample and subgroups were between .57 and .71 with lower alphas for subgroups with disadvantaged socioeconomic status. Findings suggest that the C-CRS has the potential to assess children's resourcefulness skills in the Taiwanese population.

Fabrication and evaluation of Au-Pd core-shell nanocomposites for dechlorination of diclofenac in water.

Nanocomposites with core-shell structure usually exhibit excellent catalytic properties due to unique interfaces and synergistic effect among composites. In this study, Au-Pd bimetallic nanoparticles (NPs) with core-shell structure (Au-Pd cs) by using Au NPs as core and Pd as shell were successfully fabricated and, for the first time, were used to investigate the dechlorination of diclofenac (DCF) at H2 atmosphere in water at room temperature. The degradation products were studied as well by using HPLC/Q-ToF MS/MS. The operational factors such as pH and composition of the Au-Pd cs were also studied. The results showed that nearly 100% of DCF (30 mg L(-1), 50 mL, pH=7) was dechlorinated in 4.5 h by 10 mL of 56 mg L(-1) of Au-Pd cs. Ninety per cent of DCF was degraded in 6.5 h by the mixture of Au and Pd NPs. However, the individual Au NPs had no obvious effect in degrading DCF and the monometallic Pd NPs with comparable concentration only degraded less than 20% of DCF. Furthermore, the reaction mechanism of this catalytic process was studied in detail. It was found that the degradation was a second-order exponential reaction. The two main degradation products were obtained by cleaving the carbon-halogen bond of DCF and this made the degradation products more environmentally friendly.

A review on medical waste treatment in COVID-19 pandemics: Technologies, managements and future strategies.

Since the outbreak of COVID-19 few years ago, the increasing of the number of medical waste has become a huge issue because of their harmful impact to environment. A major concern associated to the limitation of technologies for dealing with medical waste, especially conventional technologies, are overcapacities since pandemic occurs. Moreover, the outbreak of new viruses from post COVID-19 should become a serious attention to be prevented not only environmental issues but also the spreading of viruses to new pandemic near the future. The high possibility of an outbreak of new viruses and mutation near the future should be prevented based on the experience associated with the SARS-CoV-2 virus in the last 3 yr. This review presented information and strategies for handling medical waste during the outbreak of COVID-19 and post-COVID-19, and also information on the current issues related to technologies, such as incineration, pyrolysis/gasification, autoclaves and microwave treatment for the dealing with high numbers of medical waste in COVID-19 to prevent the transmission of SARS-CoV-2 virus, their advantages and disadvantages. Plasma technology can be considered to be implemented as an alternative technology to deal with medical waste since incinerator is usually over capacities during the pandemic situation. Proper treatment of specific medical waste in pandemics, namely face masks, vaccine vials, syringes, and dead bodies, are necessary because those medical wastes are mediums for transmission of the SARS-CoV-2 virus. Furthermore, emission controls from incinerator and plasma are necessary to be implemented to reduce the high concentration of CO2, NOx, and VOCs during the treatment. Finally, future strategies of medical waste treatment in the perspective of potential outbreak pandemic from new mutation viruses are discussed in this review paper.Implications: Journal of the air and waste management association may consider our review paper to be published. In this review, we give important information related to the technologies, managements and strategies for handling the medical waste and control the transmission of SARS-CoV-2 virus, starting from proper technology to control the high number of medical waste, their pollutants and many strategies for controlling the spreading of SARS-CoV-2 virus. Moreover, this review also describes some strategies associated with control the transmission not only the SARS-CoV-2 virus but also the outbreak of new viruses near the future.

Development and Validation of a Breastfeeding Health Literacy Scale (BFHLS) for Taiwanese Pregnant Women.

BACKGROUND: Breastfeeding is the best source of nutrition for infants. Health literacy is a critical factor affecting breastfeeding rates. RESEARCH AIMS: The aim of this research was to develop and test the Breastfeeding Health Literacy Scale to determine its validity and reliability. METHODS: This study featured a cross-sectional telephone survey design. Researchers reviewed the literature and used expert opinions to develop the content-validated 30-item Breastfeeding Health Literacy Scale covering five dimensions. We examined internal consistency, exploratory factor analysis, and confirmatory factor analysis to assess reliability and construct validity. A Taiwanese government organization provided potential participants' contact information. After mailing an invitation letter, researchers phoned all participants to invite participation, obtain oral consent and complete a Breastfeeding Health Literacy Scale and collect demographic data. RESULTS: Participants (N = 300) had a mean age of 31.8 (SD = 4.66) years. The item-level content validity index was 0.67 to 1.00 and scale-content validity index was 0.94. After performing exploratory factor analysis, three factors were extracted. Examining content factor analysis for the three factors resulted in χ2/df = 2.05; p < .001; goodness of fit index = 0.90; Comparative Fit Index (CFI) = 0.96; and Root Mean Square Error of Approximation (RMSEA) = 0.06. Cronbach's alphas on the total scale and the subscales ranged from 0.87 to 0.94. Women with multigravida, breastfeeding information from physicians and nurses, and previous breastfeeding experience had better breastfeeding health literacy. CONCLUSIONS: Psychometric analysis demonstrated that the newly developed 20-item Breastfeeding Health Literacy Scale is a valid self-assessment instrument. Improving breastfeeding health literacy during pregnancy could help enable breastfeeding success.

Characterizing sector-oriented roadside exposure to ultrafine particles (PM0.1) via machine learning models: Implications of covariates influences on sectors variability.

Ultrafine particles (UFPs; PM0.1) possess intensified health risk due to their smaller size and unique spatial variability. One of major emission sources for UFPs is vehicle exhaust, which varies based on the traffic composition in each type of roadside sector. The current challenge of epidemiological UFPs study is limited characterization ability due to expensive instruments. This study assessed the UFPs particle number concentrations (UFPs PNC) exposure dose for typical healthy adults and children at three different roadside sectors, including industrial roadside (IN), residential roadside (RS), and urban background (UB). Furthermore, this study also developed and utilized machine learning (ML) algorithms that could accurately characterize the UFPs exposure dose and explain the covariates effects on the model outputs, representing the intra-urban variability of UFPs between sectors. It was found that the average inhaled UFPs dose for healthy adults and children during off-peak season (warm period) were 1.71 ± 0.19 × 1010; 1.28 ± 0.22 × 1010; 1.09 ± 0.18 × 1010 #/hour and 1.33 ± 0.15 × 1010; 0.99 ± 0.17 × 1010; 0.86 ± 0.14 × 1010 #/hour at IN, RS, UB. Inhaled UFPs were mainly deposited in tracheobronchial (TB) respiratory fraction for adults (67.7%) and in alveoli (ALV) fraction for children (67.5%). Among three ML algorithms implemented in this study, XGBoost possessed the highest UFPs PNC exposure dose estimation performances with R2 = 0.965; 0.959; 0.929 & RMSE = 0.79 × 108; 0.54 × 108; 0.15 × 105 #/hour at IN, RS, and UB which then followed by multiple linear regression (MLR), and random forest (RF). Furthermore, SHAP analysis from the XGBoost model has successfully pointed out the spatial variability of each roadside sector by quantifying the approximated contributions of covariates to the model's output. Findings in this study highlighted the potential use of ML models as an alternative for preliminary particle exposure source apportionment.

Identifying spatiotemporal trends of SARS-CoV-2 RNA in wastewater: from the perspective of upstream and downstream wastewater-based epidemiology (WBE).

Recently, many efforts have been made to address the rapid spread of newly identified COVID-19 virus variants. Wastewater-based epidemiology (WBE) is considered a potential early warning tool for identifying the rapid spread of this virus. This study investigated the occurrence of SARS-CoV-2 in eight wastewater treatment plants (WWTPs) and their sewerage systems which serve most of the population in Taoyuan City, Taiwan. Across the entire study period, the wastewater viral concentrations were correlated with the number of COVID-19 cases in each WWTP (Spearman's r = 0.23-0.76). In addition, it is confirmed that several treatment technologies could effectively eliminate the virus RNA from WWTP influent (> 90%). On the other hand, further results revealed that an inverse distance weighted (IDW) interpolation and hotspot model combined with the geographic information system (GIS) method could be applied to analyze the spatiotemporal variations of SARS-CoV-2 in wastewater from the sewer system. In addition, socio-economic factors, namely, population density, land use, and income tax were successfully identified as the potential drivers which substantially affected the onset of the COVID-19 outbreak in Taiwan. Finally, the data obtained from this study can provide a powerful tool in public health decision-making not only in response to the current epidemic situation but also to other epidemic issues in the future.

Simultaneous detection of 5-methylcytosine and 5-hydroxymethylcytosine at specific genomic loci by engineered deaminase-assisted sequencing.

Cytosine modifications, particularly 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC), play crucial roles in numerous biological processes. Current analytical methods are often constrained to the separate detection of either 5mC or 5hmC, or the combination of both modifications. The ability to simultaneously detect C, 5mC, and 5hmC at the same genomic locations with precise stoichiometry is highly desirable. Herein, we introduce a method termed engineered deaminase-assisted sequencing (EDA-seq) for the simultaneous quantification of C, 5mC, and 5hmC at the same genomic sites. EDA-seq utilizes a specially engineered protein, derived from human APOBEC3A (A3A), known as eA3A-M5. eA3A-M5 exhibits distinct deamination capabilities for C, 5mC, and 5hmC. In EDA-seq, C undergoes complete deamination and is sequenced as T. 5mC is partially deaminated resulting in a mixed readout of T and C, and 5hmC remains undeaminated and is read as C. Consequently, the proportion of T readouts (P T) reflects the collective occurrences of C and 5mC, regulated by the deamination rate of 5mC (R 5mC). By determining R 5mC and P T values, we can deduce the precise levels of C, 5mC, and 5hmC at particular genomic locations. We successfully used EDA-seq to simultaneously measure C, 5mC, and 5hmC at specific loci within human lung cancer tissue and their normal counterpart. The results from EDA-seq demonstrated a strong concordance with those obtained from the combined application of BS-seq and ACE-seq methods. EDA-seq eliminates the need for bisulfite treatment, DNA oxidation or glycosylation and uniquely enables simultaneous quantification of C, 5mC and 5hmC at the same genomic locations.

Antifouling CuO@TiO2 coating on plasma-grafted PAA/PES membrane based on photocatalysis and hydrogen peroxide activation.

Because of the small size effect leading to the high bandgap of TiO2 P25, the photocatalytic membrane using this photocatalyst has low antifouling efficiency. This study prepared CuO@TiO2 composite photocatalyst with a lower bandgap than TiO2 P25 and used it as antifouling coatings on the PES membrane with PAA intermediate adhesive layer. PAA was grafted onto the surface of the PES membranes through free radicals generated by the cold plasma treatment of the PES membrane. The composite photocatalysts were characterized by FTIR, SEM-EDS, TEM-EDS, XRD, BET, UV-Vis DRS, XPS, and ESR methods demonstrating high surface area (51.0 m2/g), decreased bandgap, and the formation of active free radicals under UV light irradiation. Under photocatalysis and hydrogen peroxide activation, the degradation of AB260 (acid blue 260) catalyzed by 10%CuO@TiO2 reached about 92% after 60 min. Besides, the photocatalytic and antifouling activities of CuO@TiO2/PAA/PES membranes are high and stable over five continuous cycles. The water flux of the modified membrane was not significantly influenced and only decreased about 10% compared to the pristine membrane. In addition, the flux recovery ratios (FRR) of fouled membranes treated by photocatalysis were almost 100%.

Antifouling catalytic mixed-matrix membranes based on polyethersulfone and composition-optimized Zn-Cu-Fe-O CWAO catalyst under dark ambient conditions.

Besides photocatalysts, novel catalytic wet-air oxidation (CWAO) catalysts capable of operating under mild conditions are a potential candidate to fabricate antifouling filtration membranes. This study optimized the CWAO catalyst consisting of three metal oxide components (ZnO, CuO, and Fe3O4) and used it to fabricate composite membranes with PES (polyethersulfone). The catalyst was characterized by methods such as FTIR, BET, XRD, UV-Vis DRS, XPS, ESR. The activity of the catalyst and the composite membranes was tested by the Acid Yellow 42 (AY42) degradation experiments in both cases with and without hydrogen peroxide at room conditions with air aeration. The pure water fluxes of composite membranes were also investigated based on a vacuum filtration system. The major degradation pathways of AY42 by the catalyst were proposed from the DFT (Density Functional Theory) and NBO (Natural Bond Orbital) calculations. The results showed that the optimal catalyst has molar ratios of Zn, Cu, and Fe metal ions of 0.05, 0.588, and 0.362, respectively, with AY42 decomposition efficiency of 88% in 3 h. The main factors affecting the catalytic efficiency of the CWAO catalyst determined from the trapping experiment were e- and O2. The results from different materials characterization methods have demonstrated the successful synthesis of the catalyst with a high surface area (103.5 m2/g) and small pore diameters (∼10 nm). The AY42 degradation of composite membranes was stable over five repeated cycles with over 70% efficiency. The pure water fluxes of composite membranes have also been significantly improved and are proportional to catalyst contents.

LEAP2 is a more conserved ligand than ghrelin for fish GHSRs.

Recently, liver-expressed antimicrobial peptide 2 (LEAP2) was identified as an endogenous antagonist and an inverse agonist of the ghrelin receptor GHSR. However, its functions in lower vertebrates are not well understood. Our recent study demonstrated that both LEAP2 and ghrelin are functional towards a fish GHSR from Latimeria chalumnae, an extant coelacanth believed to be one of the closest ancestors of tetrapods. However, amino acid sequence alignment identified that the 6.58 position (Ballesteros-Weinstein numbering system) of most fish GHSRs are not occupied by an aromatic Phe residue, which is absolutely conserved in all known GHSRs from amphibians to mammals, and is responsible for human GHSR binding to its agonist, ghrelin. To test whether these unusual fish receptors are functional, we studied the ligand binding properties of three representative fish GHSRs, two from Danio rerio (zebrafish) and one from Larimichthys crocea (large yellow croaker). After overexpression in human embryonic kidney 293T cells, the three fish GHSRs retained normal binding to all tested LEAP2s, except for a second LEAP2 from L. crocea. However, they displayed almost no binding to all chemically synthesized n-octanoylated ghrelins, despite these ghrelins all retaining normal function towards human and coelacanth GHSRs. Thus, it seems that LEAP2 is a more conserved ligand than ghrelin towards fish GHSRs. Our results not only provided new insights into the interaction mechanism of GHSRs with LEAP2s and ghrelins, but also shed new light on the functions of LEAP2 and ghrelin in different fish species.