Neurobehavioral toxic effects and mechanisms of 2-aminobenzothiazole exposure on zebrafish.

2-Aminobenzothiazole (NTH), a benzothiazole derivative, exhibits potent biochemical activities and plays a significant role in modern industry. Widespread and intensive utilization of NTH has led to its detection in aquatic environments, encompassing both groundwater and surface water. Despite its wide usage, the effect of NTH on developmental neurotoxicity in aquatic organisms remains uncharted. Therefore, the aim of this investigation was to create exposure models for short- and long-term studies in order to analyze the neurobehavioral toxic impact of NTH (0, 50, 500, and 5000 µg/L) on zebrafish, which includes motor function, anxiety, and memory performance, as well as to examine the mechanism of neurotoxicity. The results revealed a significant suppression of initial embryonic mobility by NTH. However, during short-term exposure experiments, it did not significantly impact the developmental neurobehavioral functions of zebrafish. In addition, significant effects on zebrafish were observed after long-term exposure to 50 and 500 µg/L NTH, mainly impacting locomotion, social behavior, anxiety, and cognitive functions. Moreover, NTH caused oxidative damage in adult zebrafish brain tissue, which was accompanied by abnormal expression of oxidative damage-related genes. Furthermore, the Real-Time PCR results indicated a significant suppression of genes related to exposure to NTH, specifically those in the GABA synthesis pathway (gabrg2, gad2, gad1b, and abat) and the 5-HT synthesis pathway (tph2, tph1b, pet1, and htr1aa). Taken together, this study demonstrates for the first time that chronic exposure to NTH decreases the expression of genes associated with the zebrafish GABA synthesis pathway and the 5-HT synthesis pathway. This suppression is accompanied by oxidative damage, ultimately resulting in neurobehavioral changes related to motor ability, anxiety, and memory performance.

Potential adverse outcome pathway (AOP) of emamectin benzoate mediated cardiovascular toxicity in zebrafish larvae (Danio rerio).

Emamectin benzoate (EMB) is an efficient insecticide which widely used as an anthelmintic drug additive in aquaculture fish. However, its extensive use has resulted in widespread pollution in the aquatic environment. Previous studies have identified the potential developmental and neurotoxic effects of EMB, however, systematic studies pertaining to the cardiovascular toxic effects of EMB on fish are scarce. In this study, zebrafish embryos were exposed to EMB at concentrations of 0, 0.1, 0.25, 0.5, 1, 2, 4, and 8 mg/L for 3 days, aiming to investigate the cardiovascular toxic effects of EMB via examining morphology, cardiac function, and vascular development phenotypes. It revealed that EMB exposure led to marked deteriorated effects, including adverse effects on mortality, hatching rate, and general morphological traits, such as malformation, heart rate, body length, and eye area, in zebrafish embryos/larvae. Furthermore, EMB exposure resulted in abnormal cardiac function and vascular development, triggering neutrophil migration and aggregation toward the pericardial and dorsal vascular regions, and finalized apoptosis in the zebrafish heart region, these phenomena were further deciperred by the transcriptome analysis that the Toll-like receptor pathway, P53 pathway, and apoptotic pathway were significantly affected by EMB exposure. Moreover, the molecular docking and aspirin anti-inflammatory rescue assays indicated that TLR2 and TLR4 might be the potential targets of EMB. Taken together, our study provides preliminary evidence that EMB may induce apoptosis by affecting inflammatory signaling pathways and eventually lead to abnormal cardiovascular development in zebrafish. This study provides a simple toxicological AOP framework for safe pesticide use and management strategies.

High-Precision In Situ Total Alkalinity Analyzer Capable of Month-Long Observations in Seawaters.

Total alkalinity (TA) is an essential variable for the study of physical and biogeochemical processes in coastal and oceanic systems, and TA data obtained at high spatiotemporal resolutions are highly desired. The performance of the current in situ TA analyzers/sensors, including precision, accuracy, and deployment duration, cannot fully meet most research requirements. Here, we report on a novel high-precision in situ analyzer for surface seawater TA (ISA-TA), based on an automated single-point titration with spectrophotometric pH detection, and capable of long-term field observations. The titration was carried out in a circulating loop, where the titrant (a mixture of HCl and bromocresol green) and seawater sample were mixed in a constant volume ratio. The effect of ambient temperature on the TA measurement was corrected with an empirical formula. The weight, height, diameter, and power consumption of ISA-TA were 8.6 kg (in air), 33 cm, 20 cm, and 7.3 W, respectively. A single measurement required ∼7 min of running time, ∼32 mL of seawater, and ∼0.6 mL of titrant. ISA-TA was able to operate continuously in the field for up to 30 days, and its accuracies in the laboratory and field were 0.5 ± 1.7 µmol kg-1 (n = 13) and 10.3 ± 2.8 µmol kg-1 (n = 29) with precisions of 0.6-0.8 µmol kg-1 (n = 51) and 0.2-0.7 µmol kg-1 (n = 8), respectively. This study provides the research community with a new tool to obtain seawater TA data of high temporal resolution.

Neurodevelopmental Toxicity of Emamectin Benzoate to the Early Life Stage of Zebrafish Larvae (Danio rerio).

Emamectin benzoate (EMB) is a widely used pesticide and feed additive in agriculture and aquaculture. It easily enters the aquatic environment through various pathways, thus causing adverse effects on aquatic organisms. However, there are no systematic studies regarding the effects of EMB on the developmental neurotoxicity of aquatic organisms. Therefore, the aim of this study was to evaluate the neurotoxic effects and mechanisms of EMB at different concentrations (0.1, 0.25, 0.5, 1, 2, 4 and 8 µg/mL) using zebrafish as a model. The results showed that EMB significantly inhibited the hatching rate, spontaneous movement, body length, and swim bladder development of zebrafish embryos, as well as significantly increased the malformation rate of zebrafish larvae. In addition, EMB adversely affected the axon length of motor neurons in Tg (hb9: eGFP) zebrafish and central nervous system (CNS) neurons in Tg (HuC: eGFP) zebrafish and significantly inhibited the locomotor behavior of zebrafish larvae. Meanwhile, EMB induced oxidative damage and was accompanied by increasing reactive oxygen species in the brains of zebrafish larvae. In addition, gene expression involvement in oxidative stress-related (cat, sod and Cu/Zn-sod), GABA neural pathway-related (gat1, gabra1, gad1b, abat and glsa), neurodevelopmental-related (syn2a, gfap, elavl3, shha, gap43 and Nrd) and swim bladder development-related (foxa3, pbxla, mnx1, has2 and elovlla) genes was significantly affected by EMB exposure. In conclusion, our study shows that exposure to EMB during the early life stages of zebrafish significantly increases oxidative damage and inhibits early central neuronal development, motor neuron axon growth and swim bladder development, ultimately leading to neurobehavioral changes in juvenile zebrafish.

The toxic effect of bisphenol AF and nanoplastic coexposure in parental and offspring generation zebrafish.

Microplastics (MPs) and bisphenol AF (BPAF) are two environmental pollutants that usually coexist in the natural environment. Studies of MPs or BPAF have gradually increased in recent years, but few studies have focused on the combination toxic effects. In this study, the subchronic model of adult zebrafish was exposed to 1 mg/L nanolevel microplastics and 200 µg/L BPAF for 45 days; the parental zebrafish were spawning every 3 days during exposure, and the effects of continuous poisoning were examined on the offspring after 1-9 spawns. The results showed that single BPAF exposure or BPAF and nanoplastic coexposure can both decrease the number of eggs laid and the locomotor behavior of parental zebrafish and impact the hatching rate, mortality, body length and locomotor behavior of offspring zebrafish, especially in 7-9 spawn. BPAF were accumulated in parental zebrafish intestinal in 334.62 ng/g in BPAF group and 594.52 ng/g in nm+BPAF group, and accumulated in whole offspring zebrafish for 281.6 ng/g in BPAF group and 321.46 ng/g in nm+BPAF group. Neurodevelopmental, inflammation, apoptosis and oxidative stress-related genes were also significantly increased after 7-9 spawn. In addition, the exacerbated accumulation in the BPAF+nm group in parental and offspring zebrafish may be the reason for the accelerated toxic effect in the present research. In this study, we investigated the combined effects of nanoplastics and BPAF on parental and offspring zebrafish in the aquatic environment to identify the accumulative toxic effects and provide new experimental support for assessing the effects of coexposure on aquatic organisms.

Developmental and Reproductive Impacts of Four Bisphenols in Daphnia magna.

Bisphenol A (BPA) is a typical endocrine-disrupting chemical (EDC) used worldwide. Considering its adverse effects, BPA has been banned or strictly restricted in some nations, and many analogs have been introduced to the market. In this study, we selected three representative substitutes, BPS, BPF, and BPAF, along with BPA, to assess the developmental and reproductive effects on Daphnia magna. The F0 generation was exposed to bisphenols (BPs) at an environmentally relevant concentration (100 µg/L) for 21 d; then the embryo spawn at day 21 was collected. Behavior traits, the activity of antioxidant enzymes, and gene transcription were evaluated at three developmental stages (days 7, 14, and 21). Notably, body length, heart rate, and thoracic limb beating were significantly decreased, and D. magna behaved more sluggishly in the exposed group. Moreover, exposure to BPs significantly increased the antioxidant enzymatic activities, which indicated that BPs activated the antioxidant defense system. Additionally, gene expression indicated intergenerational effects in larvae, particularly in the BPAF group. In conclusion, BPA analogs such as BPF and BPAF showed similar or stronger reproductive and developmental toxicity than BPA in D. magna. These findings collectively deepen our understanding of the toxicity of BPA analogs and provide empirical evidence for screening safe alternatives to BPA.

Comprehensive analysis of transcriptomics and metabolomics to understand tail-suspension-induced myocardial injury in rat.

Background/Aims: The effect and underlying mechanism of microgravity on myocardium still poorly understood. The present study aims to reveal the effect and underlying mechanism of tail-suspension-induced microgravity on myocardium of rats. Methods: Tail-suspension was conducted to simulate microgravity in rats. Echocardiography assay was used to detect cardiac function. The cardiac weight index was measured. Hematoxylin and eosin (HE) staining and transmission electron microscopy assay were conducted to observe the structure of the tissues. RNA sequencing and non-targeted metabolomics was employed to obtain transcriptome and metabolic signatures of heart from tail-suspension-induced microgravity and control rats. Results: Microgravity induced myocardial atrophy and decreased cardiac function in rats. Structure and ultrastructure changes were observed in myocardium of rats stimulated with microgravity. RNA sequencing for protein coding genes was performed and identified a total of 605 genes were differentially expressed in myocardium of rats with tail suspension, with 250 upregulated and 355 downregulated (P < 0.05 and | log2fold change| > 1). A total of 55 differentially expressed metabolites were identified between the two groups (VIP > 1 and P < 0.05) by the metabolic profiles of heart tissues from microgravity groups and control. Several major pathways altered aberrantly at both transcriptional and metabolic levels, including FoxO signaling pathway, Amyotrophic lateral sclerosis, Histidine metabolism, Arginine and proline metabolism. Conclusion: Microgravity can induce myocardial atrophy and decreases cardiac function in rats and the molecular alterations at the metabolic and transcriptomic levels was observed, which indicated major altered pathways in rats with tail suspension. The differentially expressed genes and metabolites-involved in the pathways maybe potential biomarkers for microgravity-induced myocardial atrophy.

Syndrome Differentiation of Chinese Medicine in Mars 500 Long-Term Closed Environment.

OBJECTIVE: To summarize and elucidate the characteristics and evolvement of Chinese medicine (CM) patterns reflecting the physical and mental conditions of participants in the Mars 500 long-term closed environment. METHODS: The DS01-T Digital TCM Four-Diagnostic Instrument and CM Inquiring Diagnostic Questionnaire were used to collect information from 6 participants in the Mars 500 International Joint Research Project, through diagnostic methods of observation, palpation and inquiry according to CM theory. During the 520 days of the experiment, data collection was performed 37 times; a total of over 400 digital images of tongues and facial complexion and over 20,000 data were collected. These data were then analyzed by a team of experts in CM, statistics, and data mining. RESULTS: The CM pattern evolvement of participants in the long-term closed environment followed some common trends. Qi deficiency was the main CM pattern observed, with individual features depending on constitutional differences [manifested in varying degrees of accompanying patterns of Gan (Liver) qi stagnation, Pi (Spleen) deficiency, dampness encumbering, or yin deficiency]. CONCLUSION: The research has verified the effectiveness of CM syndrome differentiation based on the four diagnostic methods, which should serve as a solid foundation for observation, monitoring, and intervention in regard to the health conditions of astronauts in long-term space flights in the future.

[Evaluation on biodegradability of hydrocarbon biomarkers in two crude oils under laboratory conditions].

Biodegradabilities of several hydrocarbon biomarker groups, including isoprene, hopanes and steranes in a medium-crude oil BZ34-1 and a heavy-crude oil SZ36-1 from offshore, were determined under laboratory conditions. The results of GC-MS analysis showed that isoprene biomarkers such as pristane and phytane in both crude oils degraded obviously in 60-day experiment period. The degradation ratios of pristane and phytane in the medium-crude oil BZ34-1 reached 20.2% and 15.0%, respectively; while those in the heavy-crude oil SZ36-1 reached 95.6% and 75.4%, respectively. Pristane and phytane in the heavy-crude oil SZ36-1 were degraded in the early period of biodegradation, but these two biomarkers in the medium-crude oil BZ34-1 were degraded in middle and late biodegradation phases. However, hopanes and steranes in the both oils were not biodegraded obviously during the whole period. These results indicated that pristane and phytane could be used to evaluate bioremediation efficiency in the early biodegradation phase for light or medium oils, while hopanes and steranes could be used to evaluate bioremediation efficiency within the whole given experiment process.

Chinese herbal medicine and cognitive and emotional functions during 60-day head-down bed rest.

INTRODUCTION: This study aimed to test the efficacy of an oral-intake Chinese herbal medicine in enhancing the cognitive and emotional functions of individuals in a simulated microgravity condition. The herbal medicine consisted of ingredients that may enhance cognitive and emotional functions in an extreme environment. METHODS: There were 14 healthy male subjects who were randomly assigned to a Chinese medicine (CMG) or a control (CG) group and underwent a 60-d 6 degree head-down bed-rest protocol. Testing was conducted before (Day -3), throughout (Days 3, 7, 20, 40, 57), and after (Days +3, +10) the bedrest protocol. The Arrow Test, Balloon Analog Risk Task (BART), Dual Task, and Affect Grid were administered on all testing days. RESULTS: The CMG demonstrated consistently higher scores on the BART (Days 20 to 40; Mean: CMG, 43.0 to 46.2 and CG, 30.2 to 25.5) and lower levels of arousal on the Affect Grid (Days 7 to 40; Mean: CMG, 6.9 to 6.7 and CG, 8.1 to 8.0) than did the CG. The CMG showed significantly higher performance on the Arrow Test (incompatible condition) at the beginning of the bed-rest period (Day 3 to 7; Mean: 799.5 ms and 763.1 ms, respectively) which was not observed in the CG. DISCUSSIONS: Results suggest that the Chinese herbal medicine may calm subjects' emotions by lowering the arousal level. At the same time, it may have produced positive effects in enhancing advantageous risk-taking and to a lesser extent self-regulatory behaviors (in the early phase).

Neural correlates of traditional Chinese medicine induced advantageous risk-taking decision making.

This fMRI study examined the neural correlates of the observed improvement in advantageous risk-taking behavior, as measured by the number of adjusted pumps in the Balloon Analogue Risk Task (BART), following a 60-day course of a Traditional Chinese Medicine (TCM) recipe, specifically designed to regulate impulsiveness in order to modulate risk-taking behavior. The 14 participants recruited for this study were randomly assigned to the experimental and control groups and the TCM recipe (Panax, 520 mg; Astragalus membranaceous Bunge, 520 mg; Masnetitum, 840 mg; Ostrea gigas Thumb, 470 mg; Thinleaf Milkwort Root Radix Polygalae, 450 mg; and Os Draconis, 470 mg) was administered, as a diet supplement, to the seven participants in the experimental group. The neural activity of the two groups was monitored by a 3T MRI scanner, before and after the 60-day treatment. Associated with the improved advantageous risk-taking behavior seen in the experimental group, significantly stronger blood oxygenation level dependent (BOLD) responses were observed in the bilateral dorsolateral prefrontal cortex (DLPFC), left putamen, left thalamus, right insula, and right anterior cingulate cortex (ACC), regions which have previously been reported as being involved in risk-taking decision making. The effect of the TCM in improving advantageous risk-taking decision making appears to have been related to the enhanced efficiency of the cognitive affective system, the PFC-ACC-insula-striatum network, which functions to inhibit impulsiveness, to sensitize reward-related information, and to allow the opportunity, during risk estimation, to evaluate potential gains and losses. The findings of this study suggest that interventions acting on factors modulating risk-taking decision making could have a beneficial effect in terms of optimizing risk-taking behavior.