Variability in fecal metabolome depending on age, PFBS pollutant, and fecal transplantation in zebrafish: A non-invasive diagnosis of health

To protect the wellbeing of research animals,certain non-invasive measures are in increasing need to facilitate an early diagnosis of health and toxicity.In this study,feces specimen was collected from adult zebrafish to profile the metabolome fingerprint.Variability in fecal metabolite composition was also distinguished as a result of aging,perfluorobutanesulfonate(PFBS)toxicant,and fecal transplantation.The results showed that zebrafish feces was very rich in a diversity of metabolites that belonged to several major classes,including lipid,amino acid,carbohydrate,vitamin,steroid hormone,and neurotransmitter.Fecal metabolites had functional implications to multiple physiological activities,which were characterized by the enrichment of digestion,absorption,endocrine,and neurotransmission processes.The high richness and functional involvement of fecal metabolites pinpointed feces as an abundant source of diagnostic markers.By comparison between young and aged zebrafish,fundamental modifications of fecal metabolomes were caused by aging progression,centering on the neuroactive ligand-receptor interaction pathway.Exposure of aged zebrafish to PFBS pollutant also significantly disrupted the metabolomic structure in feces.Of special concern were the changes in fecal hormone intermediates after PFBS exposure,which was concordant with the in vivo endocrine disrupting effects of PFBS.Furthermore,itwas intriguing that transplantation of young zebrafish feces efficientlymitigated the metabolic perturbation of PFBS in aged recipients,highlighting the health benefits of therapeutic strategies based on gut microbiota manipulation.In summary,the present study provides preliminary clues to evidence the non-invasive advantage of fecal metabolomics in the early diagnosis and prediction of physiology and toxicology.

Exposure to methylparaben at environmentally realistic concentrations significantly impairs neuronal health in adult zebrafish

Methylparaben(MeP)is an emerging aquatic pollutant that is found to impact neural functions.However,it still lacks a comprehensive understanding about its neurotoxicology.The present study exposed adult zebrafish to environmentally realistic concentrations(0,1,3,and 10μg/L)of MeP for 28 days,with objectives to elucidate the neurotoxic effects andmechanisms.Proteomic profiling found that MeP pollutant induced distinct mechanism of neurotoxicity as a function of sex.MeP pollutant appeared to preferentially target the neurotransmission cascade via synapse junctions.In male brain,glutamatergic neural signaling was enhanced by 10μg/L of MeP in characteristics of higher glutamate neurotransmitter content(by 61.9%)and up-regulated glutamate receptor expression by 2.6-fold relative to the control.In MeP-exposed female brain,biomarker proteins of synapse formation and regeneration had significantly lower abundance,accounting for the blockage of synaptic neurotransmission.Furthermore,under the stress of MeP pollutant,both male and female zebrafish initiated a negative feedback mechanism along stress neuroendocrine axis by down-regulating the transcriptions of corticotropin-releasing hormone and its binding protein,which subsequently decreased blood cortisol concentrations.MeP subchronic exposure also disturbed innate immune function.In particular,significant increases in lipopolysaccharide(LPS)content by 15.6%were caused by MeP exposure in male brain,thereby inducing the synthesis of pro-inflammatory cytokines.In contrast,female brain was able to adaptively up-regulate the protein expression of blood brain barrier to inhibit the infiltration of LPS endotoxin into brain.Overall,the present findings pinpoint the potent neurotoxicity of MeP pollutant even at environmentally realistic concentrations.

Fingerprinting fecal DNA and mRNA as a non-invasive strategy to assess the impact of polychlorinated biphenyl 126 exposure on zebrafish

In toxicological studies,experimental animals are generally subjected to dissection to obtain the tissues of concern,which causes great harm to the animals.In this regard,it is necessary to test and develop a non-invasive strategy to prevent the animals from anthropic injury when achieving scientific objectives.Therefore,zebrafish fecal DNA and mR NA pools were assessed by using metagenomic and transcriptomic analyses based on their potential to diagnose toxicological impairment of polychlorinated biphenyl(PCB)126,a model persistent organic pollutant.The results showed that there was abundant zebrafish DNA and mR NA in the feces,which were,however,associated with contrasting profiles of physiological activities.As compared to DNA fragments,fecal mR NA provided a better representation of zebrafish physiological status.PCB126 exposure dramatically shifted the composition of fecal zebrafish DNA and m RNA as a function of sex.The differential m RNA caused by PCB126 clearly identified the toxicological fingerprint of PCB126.In summary,this study provides preliminary clues about the potential of fecal genes(mRNA in particular)in the development of non-invasive toxicological approaches.In the future,it is expected that more works will be conducted to screen sensitive diagnostic biomarkers from feces to increase the rate and reduce the cost of ecological risk assessment.

Degradation of carbamazepine by the UVA-LED_(365)/ClO_(2)/NaClO process:Kinetics,mechanisms and DBPs yield

A mixed oxidant of chlorine dioxide(ClO_(2))and NaClO was often used in water treatment.A novel UVA-LED(_(365) nm)-activated mixed ClO_(2)/NaClO process was proposed for the degradation of micropollutants in this study.Carbamazepine(CBZ)was selected as the target pollutant.Compared with the UVA_(365)/ClO_(2) process,the UVA_(365)/ClO_(2)/NaClO process can improve the degradation of CBZ,with the rate constant increasing from 2.11×10^(−4) sec^(−1) to 2.74×10^(−4) sec^(−1).In addition,the consumption of oxidants in the UVA_(365)/ClO_(2)/NaClO process(73.67%)can also be lower than that of UVA_(365)/NaClO(86.42%).When the NaClO ratio increased,both the degradation efficiency of CBZ and the consumption of oxidants can increase in the UVA_(365)/ClO_(2)/NaClO process.The solution pH can affect the contribution of NaClO in the total oxidant ratio.When the pH range of 6.0-8.0,the combination process can generate more active species to promote the degradation of CBZ.The change of active species with oxidant molar ratio was investigated in the UVA_(365)/ClO_(2)/NaClO process.When ClO_(2) acted as the main oxidant,HO·and Cl·were the main active species,while when NaClO was the main oxidant,ClO·played a role in the system.Both chloride ion(Cl^(-)),bicarbonate ion(HCO_(3)^(-)),and nitrate ion(NO_(3)^(-))can promote the reaction system.As the concentration of NaClO in the reaction solution increased,the generation of chlorates will decrease.The UVA_(365)/ClO_(2)/NaClO process can effectively control the formation of volatile disinfection by-products(DBPs),and with the increase of ClO_(2) dosage,the formation of DBPs can also decrease.