Evidence for the Stepwise Behavioral Response Model (SBRM): the effects of Carbamate Pesticides on medaka (Oryzias latipes) in an online monitoring system

The Behavioral Responses of Koi Carp (Cyprinus carpio) to Different Temperatures: Which Is Better, Infrared or Quadrupole Technology?

Based on the homemade Physiological and Ecological Comprehensive Analysis System for Aquatic Animals (PECA-BES01), this study compared the behavioral responses of koi carp (Cyprinus carpio) at three temperature gradients using two behavioral monitoring techniques as follows: infrared tracking and quadrupole impedance. The experiment employed comprehensive behavioral strength monitoring and infrared tracking (with tracked coordinates converted to swimming velocity data) to reflect behavioral changes. Within a certain temperature range, the behavioral strength and swimming velocity of carp increased with increasing temperature, which indicated heightened activity. The average behavioral strength and swimming velocity during light conditions (over three temperature gradients) were greater than during dark conditions. The circadian rhythm of carp becomes unstable at high temperatures, which shows abnormal periodicity with earlier occurrences of diurnal time points. Results from the system's two behavioral monitoring methods were largely consistent and confirmed the reliability of PECA-BES01 in monitoring aquatic organism behavior. Simultaneously, each of the two technologies has its own characteristics. Quadrupole impedance can be used to monitor the behavioral response of fish to different water depths, whereas infrared tracking can be used to monitor the behavioral response of fish to different flow velocities. Therefore, both behavioral strength monitoring and infrared tracking monitoring are effective techniques for monitoring fish behavior and can be widely applied. This study provides scientific support for koi carp cultivation and other aquatic species aquaculture, while also aiming to deliver high-quality methodology for online monitoring of aquatic organisms.

Early developmental anomalies in zebrafish (Danio rerio) embryos induced by the Clematis florida Thunb

ETHNOPHARMACOLOGICAL RELEVANCE

The C.florida. is one of the common medicines used by She population in China, with therapeutic effects of promoting blood circulation and anti-inflammatory. According to the acute toxicity grading standard of chemical substances, this herb is a low-toxicity herb. At present, the safety of C.florida., especially its impact on early embryonic development, is still unclear.

AIM OF THE STUDY

This study investigated the toxic effects of C. florida. on early embryonic development using a zebrafish embryo model.

MATERIALS AND METHODS

In this study, we used zebrafish embryos exposed to C.florida. at early stage to assess the early developmental toxicity by analyzing the developmental toxicity phenotype, oxidative stress, cell apoptosis, total enzyme activity, behavioral trajectory, and gene expression levels.

RESULTS

Embryos of the zebrafish exposed to different concentrations of C.florida. exhibited multiple organs and systems developmental disorders, including the heart, vessels, brain, bone, liver, and so on. Especially, with the increase of drug concentration, it is observed that the developmental malformations of the cardiovascular structure and function in larvae are becoming increasingly severe. In addition, results show that the abnormalities in embryonic development may be attributed to oxidative stress induced by apoptosis and activation of immune system resulting from an imbalance in the hematopoietic system.

CONCLUSIONS

This study provides a comprehensive and detailed summary of the toxic effects of C.florida. on embryonic development, which contributes to a deeper understanding of the potential adverse developmental consequences, and also prompt people to pay considerable attention to its treatment in medicinal practice.

Potential effects of internal physio-ecological changes on the online biomonitoring of water quality: The behavior responses with circadian rhythms of zebrafish (Danio rerio) to different chemicals

The online biomonitoring of aquatic accidental pollution is very important to realize the assessment of complex toxicity. However, the monitoring results would be affected greatly by the internal physio-ecological changes of test organisms, and circadian rhythms might contribute greatly to this kind of effects. In the present study, the behavior responses of zebrafish (Danio rerio) to different concentrations of Deltamethrin, Atrazine, and Thallium (Tl) in 15 days were investigated using an online behavior monitoring system. The results showed that the average behavior strength (BS) value of dark period (0.71 ± 0.16) was lower than that of light period (0.88 ± 0.09) in the control group. Similar pattern was observed in all other treatments with negative relationship between exposure concentrations and mean BS values. It is concluded that the 24 h circadian rhythms in the behavior responses of zebrafish (Danio rerio) could be observed clearly in the online biomonitoring system, and the online monitoring results would be affected obviously in the characteristics of behavior periodicity abnormal and time delay. Therefore, it is suggested that internal physio-ecological characteristics of organisms must be considered once they have the chance to play roles in bio-induced technologies. More investigations are warranted to clear the effects of internal physio-ecological changes on the exported results.

Behavior responses of zebrafish (Danio rerio) to aquatic environmental stresses in the characteristic of circadian rhythms

As behavior shows a distinct circadian rhythm, it is hypothesized that circadian rhythms based on zebrafish (Danio rerio) behavior responses could be affected by contaminants in this study, and then the behavior strength of zebrafish exposed to 0.005 mg/L Cadmium chloride (CdCl₂), 0.01 mg/L Dibasic Sodium Phosphate (Na₂HPO₄), 0.002 mg/L deltamethrin, and 0.003 mg/L atrazine for 6 days is used to illustrate the possibility of behavior circadian rhythms as an indicator in the environmental stress assessment. Statistical analysis with p < 0.01 shows that a clear difference between average values of BS during dark period (AVD) and those during light period (AVL) could be observed, and 24 h circadian rhythms do exist in zebrafish behavior responses. Both BS values and circadian rhythms of zebrafish can be affected in the aspect of periodicity with clear time delay, which were 1 h delay in CdCl₂, 4 h delay in Na₂HPO₄, 4 h delay in deltamethrin, and 1 h delay in atrazine. Behavior circadian rhythms were disturbed according to the repetitive cycles after autocorrelation analysis, and the toxic effects of different chemicals could be reflected by the profiles of the Self-Organizing Map (SOM), which indicated the circadian rhythm disorder in different degrees. These results deduced from the statistical analysis, autocorrelation and SOM strongly supported that circadian rhythms based on zebrafish BS could be used as an indicator in the environmental stress assessment.

Daphnia swimming behaviour as a biomarker in toxicity assessment: A review

Daphnia is a motile common model organism widely used in ecotoxicological testing. Although mortality and immobilisation are the main endpoints used for determination of toxicity, detection of subtle alterations induced by some chemicals particularly at lower levels may require more sensitive biomarkers. As a number of studies indicated that swimming behaviour may be altered by pesticides, nanoparticles, bacterial products or other chemicals, analysis of its various parameters is considered as a novel methodological approach for toxicity assessment and monitoring of water quality. This paper presents the current state of knowledge on the effects induced by various chemical compounds on the parameters of swimming behaviour of Daphnia and systems developed for its analysis. Advantages and limitations of swimming behaviour as a tool in toxicological studies are also discussed.

The Role of AChE in Swimming Behavior of Daphnia magna: Correlation Analysis of Both Parameters Affected by Deltamethrin and Methomyl Exposure

The unpredictable toxicity of insecticides may cause behavior disorder of biological organisms. In order to assess the role of acetylcholinesterase (AChE) in swimming behavior of Daphnia magna, a correlation analysis of both parameters in 24 h exposure of deltamethrin (DM) and methomyl (MT) was investigated. The behavior responses of D. magna in DM (13.36 μg/L and 33.40 μg/L) and MT (19.66 μg/L and 49.15 μg/L) suggested that recovery behavior in the adjustment phase was crucial, and behavior homeostasis provided them with an optimal way to achieve a wider tolerance against environmental stress. During the experiment, positive effects on AChE activity occurred in the beginning of the exposure. Even though the de novo synthesis of AChE in D. magna might help it recover, the AChE inhibition in different treatments could be observed. Some induction effects on AChE activity at the beginning of exposure occurred, and a 50% decrease may cause toxic effects on behavior. In most treatments, the results showed that both behavior strength and AChE activity stayed in the same field within a correlation circle. These results illustrated that the environmental stress caused by both DM and MT could inhibit AChE activity and subsequently induce a stepwise behavior response, though both pesticides affect it as direct and indirect inhibitors, respectively.

Cadmium stress assessment based on the electrocardiogram characteristics of zebra fish (Danio rerio): QRS complex could play an important role

The electrocardiogram (ECG) of zebra fish (Danio rerio) expresses cardiac features that are similar to humans. Here we use sharp microelectrode measurements to obtain ECG characteristics in adult zebra fish and analyze the effects of cadmium chloride (CdCl₂) on the heart. We observe the overall changes of ECG parameters in different treatments (0.1 TU, 0.5 TU and 1.0 TU CdCl₂), including P wave, Q wave, R wave, S wave, T wave, PR interval (atrial contraction), QRS complex (ventricular depolarization), ST segment, and QT interval (ventricular repolarization). The trends of the ECG parameters showed some responses to the concentration and exposure time of CdCl₂, but it was difficult to obtain more information about the useful indicators in water quality assessment depending on tendency analysis alone. A self-organizing map (SOM) showed that P values, R values, and T values were similar; R wave and T wave amplitude were similar; and most important, QRS value was similar to the CdCl₂ stress according to the classified data patterns including CdCl₂ stress (E) and ECG components based on the Ward linkage. It suggested that the duration of QRS complex was related to environmental stress E directly. The specification and evaluation of ECG parameters in Cd²⁺ pollution suggested that there is a markedly significant correlation between QRS complex and CdCl₂ stress with the highest r (0.729) and the smallest p (0.002) among all ECG characteristics. In this case, it is concluded that QRS complex can be used as an indicator in the CdCl₂ stress assessment due to the lowest AIC data abased on the linear regression model between the CdCl₂ stress and ECG parameters.

Behavior persistence in defining threshold switch in stepwise response of aquatic organisms exposed to toxic chemicals

As a characteristic in bacterial colony, persistence model described the dynamics of two subpopulations (normal (n) and persister (p)). In order to illustrate the switch of "Threshold" in the stepwise behavior responses of organisms, it is hypothesized that total behavior (B_t) of organisms consists of two types in behavior tendency, intoxication (B_p) and normal/recovery behavior (B_n). Both B_p and B_n could be concurrently affected by environmental stress E, and behavior response modes (M) are decided by the relationship between E and toxicity threshold of test organisms (T_i). The results suggested stress constant λ was decided by the constant rates g_nE,g_pE, a_n and a_p. Due to different stress constant λ, the behavior responses of indicators showed great difference in different M, which included 'safe mode' (M_s), 'acclimation mode' (M_ac), 'adjustment mode' (M_aj) and 'toxic effect' (M_te). Usually, B_t during M_s could maintain around 0.8, and M_te would happen once it is lower than 0.2. According to the relationship between B_t values and E changes in 7 M_ajs, behavior persistence relying on adjustment could reflect the behavior homeostasis of organisms under environmental stress and be regarded as a threshold switch for the stepwise behavior responses. The mathematical analysis of behavior persistence allows making a quantitative prediction on environment assessment that would promote the emergence of persistence, as well as evaluating its ecological implications.

Integrative Characterization of Toxic Response of Zebra Fish (Danio rerio) to Deltamethrin Based on AChE Activity and Behavior Strength

In order to characterize the toxic response of zebra fish (Danio rerio) to Deltamethrin (DM), behavior strength (BS) and muscle AChE activity of zebra fish were investigated. The results showed that the average values of both BS and AChE activity showed a similarly decreased tendency as DM concentration increased, which confirmed the dose-effect relationship, and high and low levels of AChE and BS partly matched low and high levels of exposure concentrations in self-organizing map. These indicated that AChE and BS had slight different aspects of toxicity although overall trend was similar. Behavior activity suggested a possibility of reviving circadian rhythm in test organisms after exposure to the chemical in lower concentration (0.1 TU). This type of rhythm disappeared in higher concentrations (1.0 TU and 2.0 TU). Time series trend analysis of BS and AChE showed an evident time delayed effect of AChE, and a 2 h AChE inhibition delay with higher correlation coefficients (r) in different treatments was observed. It was confirmed that muscle AChE inhibition of zebra fish is a factor for swimming behavior change, though there was a 2 h delay, and other factors should be investigated to illustrate the detailed behavior response mechanism.

The toxic effects of deltamethrin on Danio rerio: the correlation among behavior response, physiological damage and AChE

In this work we comprehensively evaluated the effects of deltamethrin, a pyrethroid pesticide, on the behavior, physiology and acetylcholinesterase (AChE) activity of fish.

AChE inhibition: one dominant factor for swimming behavior changes of Daphnia magna under DDVP exposure

As a key enzyme that hydrolyzes the neurotransmitter acetylcholine in cholinergic synapses of both vertebrates and invertebrates, acetylcholinesterase (AChE) is strongly inhibited by organophosphates. AChE inhibition may induce the decrease of swimming ability. According to previous research, swimming behavior of different aquatic organisms could be affected by different chemicals, and there is a shortage of research on direct correlation analysis between swimming behavior and biochemical indicators. Therefore, swimming behavior and whole-body AChE activity of Daphnia magna under dichlorvos (DDVP) exposure were identified in order to clarify the relationship between behavioral responses and AChE inhibition in this study. In the beginning, AChE activity was similar in all treatments with the control. During all exposures, the tendency of AChE activity inhibition was the same as the behavioral responses of D. magna. The AChE activity of individuals without movement would decrease to about zero in several minutes. The correlation analysis between swimming behavior of D. magna and AChE activity showed that the stepwise behavioral response was mainly decided by AChE activity. All of these results suggested that the toxicity characteristics of DDVP as an inhibitor of AChE on the swimming behavior of organisms were the same, and the AChE activity inhibition could induce loss of the nerve conduction ability, causing hyperactivity, loss of coordination, convulsions, paralysis and other kinds of behavioral changes, which was illustrated by the stepwise behavioral responses under different environmental stresses.

The process-dependent impacts of dimethoate on the feeding behavior of rotifer

Traditional toxicological studies usually depict the dose-effect relationship at the given exposure time while ignore how toxic effects vary during and after the exposure. In the present study, feeding depression of the rotifer Brachionus calyciflorus under the impact of dimethoate was evaluated not only in the exposure time but also in the post-exposure time. Both the filtration rates (F) and the ingestion rates (I) of the rotifers varied during the exposure period under any concentration of dimethoate. A three-stepwise stress was observed when the rotifers were exposed to 0.2 and 1.0 mg L(-1) of the pesticide respectively, whereas 1.8 mg L(-1) dimethoate caused only one-step stress on the rotifers during the whole period. In addition, although the feeding behaviors of the rotifers recovered after the exposure, two feeding rates both got even more depressed at 8h in the post-exposure time. The latent inhibition after exposure was related to the exposure concentrations and the exposure time. Our works indicated that the impact of dimethoate on the feeding behavior of the rotifers was highly process-dependent that caused the stepwise stress during the exposure period and the latent stress after the exposure.

The stepwise behavioral responses: behavioral adjustment of the Chinese rare minnow (Gobiocypris rarus) in the exposure of carbamate pesticides

In order to illustrate the behavioral regulation in environmental stress, the behavioral responses of the Chinese rare minnow (Gobiocypris rarus) to arprocarb, carbofuran, and oxamyl were analyzed with an online monitoring system. The Self-Organizing Map (SOM) was used to define the patterns of the behavioral data obtained from treatments at concentrations of 0.1 toxic unit (TU), 1 TU, 2 TU, 5 TU, 10 TU, and 20 TU and a control. In certain cases, differences among the carbamate pesticides (CPs) tested were observed. The profiles of behavioral strength (BS) in SOM varied according to the concentration used. The time of the first significant decrease of the BS varied inversely with the CP concentrations. The results suggested that the behavioral regulation in the stepwise behavioral responses (SBR) was evident. The primary movement behaviors shown by the SBR model included no effect, stimulation, acclimation, adjustment (readjustment), and toxic effect, especially at the lower concentrations. However, higher stress (10 TU and 20 TU) might limit the function of the behavioral adjustment produced by the intrinsic response mechanisms. It was concluded that SBR, which were affected by both the concentration and the exposure time, could be used as a suitable indicator in the ecotoxicological risk assessment of CPs.