Paraquat Concentration Research Articles

Avoidance Response: A More Important Determinant of Population Immediate Decline in Guppy Fish (Poecilia reticulata Peters, 1859) Exposed to Pesticides

This study investigated the ability of Paraquat (herbicide) and Dichlorvos (insecticide) to elicit avoidance response in the population of Guppy fish, Poecilia reticulata and predict the population immediate decline (PID) of P. reticulata when exposed to both agrochemicals. A 96-h forced system (FS) bioassay was each conducted in five duplicate systems, each with a control experiment. The avoidance response was examined using a non-forced multi-compartmented static system (NFS). The guppies (n = 3 guppies per concentration of 6 compartments in quadruplet) were exposed to a gradient of Paraquat (0, 2.5, 5.0, 7.5, 10.0 and 15.0 mgL-1) and Dichlorvos (0, 1.6, 2.6, 3.0, 3.2 and 4.0 mgL-1). Their distributions were examined at 20 min intervals for a 3-h period (n=9observation periods). The results from 96-h FS were dose-dependent with the highest percentage mortality being 85.7% for Paraquat and 78.6% for Dichlorvos in their respective highest concentrations. The 3-h NFS exposure showed statistically significant concentration-dependent spatial avoidance. The P. reticulata avoided the lowest concentration of Paraquat (2.5mgL-1) and Dichlorvos (1.6 mgL-1) by 68.3% and 48.3% respectively. The avoidance increased significantly (p < 0.005) to 75%, for the highest concentrations of both test chemicals (15.0 and 4.0 mgL-1). The 3-hr AC50 value revealed that the guppies were more sensitive to Paraquat (0.37 mgL-1) than Dichlorvos (1.73 mgL-1). The PID was driven by the avoidance behavior (NFS) of the guppies rather than mortality (FS). The FS heretofore overestimate the environmental risk of contamination due to mandatory exposure of mobile organisms to contaminants. Rather than the traditional FS systems, NFS should be adopted and incorporated into typical bioassays for better predictive results.

Regulation of Paraquat for wheat crop contamination.

Paraquat is a highly toxic and persistent pesticide in soil but is still used for wheat crops in many countries. Paraquat can pose potential health hazards if it is translocated from soil into wheat grains, but no study is available for its possible translocation causing wheat grain contamination. The present study aimed at finding out Paraquat residue in wheat grains under field conditions for two crop seasons to explore the sustainability of this pesticide. The experiments were conducted scientifically under field conditions at agricultural fields Pusa, Delhi, India. The soil texture was classified as sandy loam. Paraquat dichloride 24% SL (herbicide) was applied on five fields except for control field. Paraquat in wheat grains was analyzed using HPLC equipped with a photodiode array (PDA) detector. The method of analysis was validated for the pesticide residue recovery. The results showed that there was an alarming concentration of Paraquat in wheat grains ranging between 21.6 and 49.02mgkg-1 against maximum residue level of 0.1mgkg-1. Paraquat was also found in control crop (3.1mgkg-1) due to background residue in soil even when no Paraquat was applied. Furthermore, wheat flour samples from market also gave alarming Paraquat residue (20.39, 25.88, and 27.68mgkg-1). Paraquat residue was primarily dependent on % clay in field soils. More the % clay lesser was Paraquat residue in wheat grain. Thus, Paraquat was translocated from soil into wheat grains and resulted in worrying concentration of Paraquat residue in wheat grains. Consequently, use of Paraquat for wheat crops needs to be regulated as it contaminated the soil and resulted in the wheat grain contamination posing severe health hazards for humans.

Genotoxic, biochemical and histological biomarkers of subacute concentrations of paraquat and glyphosate in Nile Tilapia.

The use of herbicides for increased food production may pose risk to non-target organisms. This study evaluated the acute toxicity, genotoxic, biochemical, and histological biomarkers of subacute concentrations of paraquat and glyphosate in Oreochromis niloticus (Nile Tilapia) for 28 days following standard methods. Glyphosate (96 hLC50 value-1.23 mg/L) was 9x more toxic than paraquat (96 hLC50 value-11.20 mg/L) against O. niloticus. Average micronucleated cells were significantly higher in the erythrocytes of O. niloticus exposed to the higher (1.12 mg/L) concentration of paraquat at day 14, both subacute concentrations of paraquat at day 28, and lower concentration (0.01 mg/L) of glyphosate at days 14 and 28 compared to the other treatments and controls. Biochemical biomarkers (MDA and GST) activities were significantly higher at both subacute concentrations of the herbicides in the exposed fish compared to the controls at day 28 only. GSH activity was significantly higher in the 0.11 mg/L paraquat concentration while SOD activity was significantly lower at both subacute concentrations of glyphosate in exposed fish compared to controls at day 28. Histological alterations observed were mild to severe shortening of the gill primary lamellar and hepatic portal inflammation of exposed fish compared to the controls. This study demonstrates the risk to non-target organisms due to herbicides’ run-off from agricultural farmlands into aquatic ecosystems at environmentally relevant or subacute concentrations. Sensitization on the responsible use of pesticides is recommended to promote responsible consumption and production and sustain life below water (United Nations Sustainable Development Goals 12 and 14 respectively).

Role of OCT3 and DRP1 in the Transport of Paraquat in Astrocytes: A Mouse Study.

Background:Paraquat (PQ) is a pesticide, exposure to which has been associated with an increased risk of Parkinson’s disease; however, PQ transport mechanisms in the brain are still unclear. Our previous studies indicated that the organic cation transporter 3 (OCT3) expressed on astrocytes could uptake PQ and protect the dopaminergic (DA) neurons from a higher level of extracellular PQ. At present, it is unknown how OCT3 levels are altered during chronic PQ exposure or aging, nor is it clear how the compensatory mechanisms are triggered by OCT3 deficiency. Dynamic related protein 1 (DRP1) was previously reported to ameliorate the loss of neurons during Parkinson’s disease. Nowadays, mounting studies have revealed the functions of astrocyte DRP1, prompting us to hypothesize that DRP1 could regulate the PQ transport capacity of astrocytes.Objectives:The present study aimed to further explore PQ transport mechanisms in the nigrostriatal system and identify pathways involved in extracellular PQ clearance.Methods:Models of PQ-induced neurodegeneration were established by intraperitoneal (i.p.) injection of PQ in wild-type (WT) and organic cation transporter-3–deficient () mice. DRP1 knockdown was achieved by viral tools in vivo and small interfering RNA (siRNA) in vitro. Extracellular PQ was detected by in vivo microdialysis. In vitro transport assays were used to directly observe the functions of different transporters. PQ-induced neurotoxicity was evaluated by tyrosine hydroxylase immunohistochemistry, in vivo microdialysis for striatal DA and behavior tests. Western blotting analysis or immunofluorescence was used to evaluate the expression levels and locations of proteins in vitro or in vivo.Results:Older mice and those chronically exposed to PQ had a lower expression of brain OCT3 and, following exposure to a i.p. loading dose, a higher concentration of extracellular PQ. DRP1 levels were higher in astrocytes and neurons of WT and mice after chronic exposure to PQ; this was supported by finding higher levels of DRP1 after PQ treatment of dopamine transporter-expressing neurons with and without OCT3 inhibition and in primary astrocytes of WT and mice. Selective astrocyte DRP1 knockdown ameliorated the neurotoxicity in mice but not in WT mice. GL261 astrocytes with siRNA-mediated DRP1 knockdown had a higher expression of alanine–serine–cysteine transporter 2 (ASCT2), and transport studies suggest that extracellular PQ was transported into astrocytes by ASCT2 when OCT3 was absent.Discussion:The present study mainly focused on the transport mechanisms of PQ between the dopaminergic neurons and astrocytes. Lower OCT3 levels were found in the older or chronically PQ-treated mice. Astrocytes with DRP1 inhibition (by viral tools or mitochondrial division inhibitor-1) had higher levels of ASCT2, which we hypothesize served as an alternative transporter to remove extracellular PQ when OCT3 was deficient. In summary, our data suggest that OCT3, ASCT2 located on astrocytes and the dopamine transporter located on DA terminals may function in a concerted manner to mediate striatal DA terminal damage in PQ-induced neurotoxicity. https://doi.org/10.1289/EHP9505

Wnt-induced secreted proteins-1 play an important role in paraquat-induced pulmonary fibrosis

BackgroundThe objective of this article is to observe the expression of Wnt-induced secreted proteins-1 (WISP1) in paraquat (PQ)-induced pulmonary fibrosis (PF) to explore the role of WISP1.MethodsHealthy individuals were included in the control group. Patients who had acute lung injury or PF were included in the PF group. Venous blood samples were collected from the patients on days 1 and 3 following PQ poisoning to detect the expression levels of the WISP1 gene and protein concentration. Any changes in the patients’ blood gas analysis index were reviewed. In addition, chest computed tomography (CT) and x-ray images were observed to evaluate the relationship between WISP1 expression and disease severity.ResultsThe expression of the WISP1 gene and the serum WISP1 protein concentration were higher in patients with PQ poisoning combined with PF than in patients without PF (P < 0.01). Serum PQ concentration was positively correlated with WISP1 gene expression (r = 0.621, P < 0.01), and serum WISP1 protein concentration (r = 0.596, P < 0.01) was considered a risk factor [odds ratio (OR) = 4.356, P < 0.05] for PQ-induced PF. Concurrently, the results of the adjusted and non-adjusted OR value for WISP1 gene expression and WISP1 protein concentration on day 1 was, respectively, as follows: OR = 12.797, 95% confidence interval (CI) (2.478–66.076), P = 0.002, OR’ = 11.353, P = 0.005; and OR = 1.545, 95% CI (1.197–1.995), P = 0.001, OR’ = 1.487, P = 0.003. The CT scan of a 20-year-old male with PQ-induced PF (20 ml) was observed, and it showed a typical hyaline-like lesion in the lungs on day 22 after poisoning; on day 33 after poisoning, the lungs showed localised consolidation combined with air bronchography.ConclusionThe expression of WISP1 was higher in the patients with PQ-induced PF compared with the patients without PF. Accordingly, WISP1 plays an important role in PQ-induced PF.

Vesicle transport related protein Synaptotagmin-1 mediates paraquat transport to antagonize paraquat toxicity

In this study, A549/PQ cells with moderate resistance to paraquat (PQ) were obtained by treating A549 cells with PQ, their growth rate was slowed down, the accumulation concentration of PQ and the levels of growth inhibition, injury and early apoptosis induced by PQ were significantly lower than those of parental A549 cells. Microarray screening and RT-qPCR detection found that Synaptotagmin-1 (SYT1) expression in drug-resistant cells was significantly increased, and PQ further enhanced its expression. After inhibiting SYT1 expression in A549/PQ cells, cell viability, intracellular PQ concentration and the expression of Bcl-2, SNAP25 and RAB26 were significantly reduced, while the mortality, early apoptosis rate and Bax expression were significantly increased. In vivo experiments also further showed that PQ promoted the expression of SYT1, SNAP25 and RAB26 in PQ-poisoned mice; when inhibiting SYT1 expression, PQ concentration in lung tissues was significantly increased, and the levels of lung injury and apoptosis were also significantly enhanced, while the expression of SNAP25 and RAB26 was significantly reduced. This indicates that PQ poisoning leads to compensatory up-regulation of vesicle transport related proteins such as SYT1 in vivo, thereby promoting PQ transmembrane transport, and then reducing the pulmonary accumulation of PQ and PQ-caused lung injury.

Design and synthesis of amphiphilic carboxyl-functionalized magnetic polymer microspheres for fast determination of paraquat and its four metabolites in human urine samples prior to ultra-high performance liquid chromatography-high resolution mass spectrometry

In cases of low concentration paraquat (PQ) poisoning, as the disease progresses over a long period of time, the prototype PQ may not be detected in the urine, which has a significant negative impact on the precise treatment of the poisoning. But PQ poisoning can also be confirmed by the detection of specific metabolites of PQ in the urine samples. In the present study, core-shell amphiphilic carboxyl-functionalized magnetic polymer microsphere (Amphiphilic-MPs-COOH) was prepared, and the as-prepared Amphiphilic-MPs-COOH was characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetry and differential thermogravimetry analyses (TG-DTG). Then, the Amphiphilic-MPs-COOH was employed as a magnetic solid-phase extraction (MSPE) adsorbent for pretreatment and rapid determination of PQ and its four metabolites from urine samples prior to ultra-high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). The extraction-elution conditions of Amphiphilic-MPs-COOH towards PQ and its metabolites were optimized in spiking urine samples to obtain the best MSPE efficiency. The adsorption mechanism of PQ and its metabolites by Amphiphilic-MPs-COOH involves electrostatic attraction and π-π stacking interactions. Moreover, the effect of different ratios of hydrophilic monomer NVP and functional monomer 4-VBA on the extraction and purification performance of PQ and its metabolites in urine samples. And the results revealed that both hydrophilic monomer and functional monomer were important for the adsorption of PQ and its metabolites, and the addition of the appropriate amount of the hydrophilic monomer NVP can improve the compatibility of the adsorbent with the urine substrate. In addition, this study compared the matrix effect of the Amphiphilic-MPs-COOH based MSPE method and the commercial Waters Oasis WCX SPE method. The results showed that the Amphiphilic-MPs-COOH based MSPE method developed in this paper had better resistance to matrix interference. Under optimal conditions, the recoveries of PQ and its metabolites were ranging from 84.5 to 103%, with relative standard deviations (RSDs) of 1.1–6.3%. While the limits of detection (LODs, S/N ≥ 3) and limits of quantification (LOQs, S/N ≥ 9) of the method were in range of 0.1–1.6 μg/L and 0.3–4.8 μg/L, respectively. Finally, the established MSPE-UPLC-HRMS method in this study was used to confirm PQ poisoning not only based on detecting PQ prototype, but also on its four metabolites, providing strong technical support for clinical precision treatment.

The herbicide paraquat alters growth and melanin production on the Cryptococcus neoformans/Cryptococcus gattii species complex

Paraquat (1,10-dimethyl-4,4-bipyridinium dichloride; PQ) is a free-radical producing herbicide that affects cell membranes and can upset the environmental balance of microorganisms present in soil, such as Cryptococcus spp. This study aimed to evaluate the in vitro activity of PQ against Cryptococcus spp. in planktonic and biofilm forms, as well as the protective effect of antioxidant agents against the antifungal effect of PQ and the kinetics of melanin production in response to PQ. Susceptibility to PQ was evaluated by microdilution. Cryptococcus sp. strains exposed to PQ were grown in media with ascorbic acid (AA) and glutathione (GSH). Melanin production was assessed in the presence of l-3,4-dihydroxyphenylalanine (l-DOPA) + PQ. The minimum inhibitory concentration of PQ against Cryptococcus spp. ranged from 8 to 256 µg/mL. Furthermore, PQ reduced biofilm formation. AA and GSH restored the fungal growth of Cryptococcus spp. exposed to PQ. In addition, l-DOPA + PQ delayed melanin production by 24 and 48 h for C. deuterogattii and C. neoformans sensu lato, respectively, suggesting that PQ induces a fitness trade-off in melanin production. Taken together, our data suggest that the antifungal effect of PQ against Cryptococcus spp. possibly exerts selective pressures interfering with biofilm formation and melanin production by these yeasts.

Degradation of commercial paraquat in a solar-Fenton pilot lagoon using iron oxalate as a chelating agent: Hydro-thermal analysis with CFD

The performance of a solar Fenton in commercial paraquat (Gramoxone) was analyzed at natural pH with paraquat (PQ) concentrations of 0.9, 0.7 and 0.1 mM. This photochemical treatment was mediated by different concentrations of ferrioxalate and hydrogen peroxide in a solar pilot lagoon which was analyzed with CFD to verify its hydrodynamic and temperature performance. PQ degradation efficiencies of 51.93%, 91.55%, and 96.54% for PQ concentrations of 0.9, 0.7, and 0.1 mM, respectively, were achieved. COD reduction percentages of 61.23%, 82%, and 92% were observed after 8 h of hydraulic retention time. The maximum mineralization was 85.90%, 80.67%, and 94%, respectively. The following ratios were tested for 0.9, 0.7, and 0.1 mM PQ: oxalate/PQ = 2.5, 3.29 and 23; H2O2/PQ = 2.14, 2.74 and 19.18. The ratios of oxalate/Fe3+ = 20 and H2O2/Fe3+ = 16 were the best for the treatment of the three PQ concentrations. These conditions were highly effective for the treatment of this herbicide. To improve the reaction rate, it is necessary to increase the accumulative energy, which would reduce the treatment time.

Fe2O3-decorated boron/nitrogen-co-doped carbon nanosheets as an electrochemical sensing platform for ultrasensitive determination of paraquat in natural water

Boron/nitrogen-co-doped carbon (BCN) nanosheets decorated with Fe2O3 nanocrystals (Fe2O3–BCN) were cast on a glassy carbon electrode (GCE) and applied as an electrochemical sensor to effectively detect paraquat (PQ), a toxic herbicide, in aqueous environments. A linear experiment performed using square wave voltammetry (SWV) under optimized experimental conditions produced a decent linear relationship and a low detection limit (LOD) of 2.74 nmol/L (S/N = 3). Repeatability, reproducibility, stability, and interference experiments confirmed that the Fe2O3–BCN/GCE system exhibited decent electrochemical sensing performance for PQ molecules. Notably, the designed sensor showed high selectivity and a decent linear relationship with PQ concentration in natural water samples. To the best of our knowledge, this is the first study on the preparation of Fe2O3–BCN nanosheets for PQ detection. The proposed sensor can be employed as an effective alternative tool for distinguishing and processing PQ.

Quantification and toxicokinetics of paraquat in mouse plasma and lung tissues by internal standard surface-enhanced Raman spectroscopy.

Paraquat is a quaternary ammonium herbicide with anexcellent herbicidal effect but ishighly toxic to human and animals. Although prohibited by many countries, paraquat intoxication occurred occasionally and caused severe consequences. Rapid and accurate determination of paraquat concentration in intoxication samples is urgently needed in theclinic to promptly evaluate the prognosis of poisoning patients. Here we report an internal standard surface-enhanced Raman spectroscopy (IS-SERS) quantification method on paraquat in mouse plasma and lung tissues for the first time. One measurement per sample was fulfilled within 10s via this IS-SERS method. Paraquat had good linearity in the range of 1 ~ 500μg/L (plasma sample) and 1 ~ 100μg/g (lung sample), with the LOD and LOQ of 0.5μg/L and 0.1μg/g (plasma sample), and 5μg/L and 1μg/g (lung sample), respectively. This IS-SERS method was validated according to the international guidelines and applied to a quantitative determination and the toxicokinetics on paraquat in mouse plasma and lung tissues. The results indicated that paraquat had a fast absorption rate and a slow elimination rate in mouse plasma and lung tissues. Paraquat was prone to accumulate in target organs after entering the blood. It also proved its good practical applicability in one clinical intoxication sample. Meanwhile, we unveiled an underestimation of free paraquat amount towards common biological sample pretreatment, a certain amount of paraquat bound to components with molecular weight less than 30kDa in the plasma; we hope it could provide some interesting information for possible clinic treatment.

Paraquat sorption- and organic matter-induced modifications of soil spectral induced polarization (SIP) signals

SUMMARY Quantifying the capacity of soils to immobilize sorbing contaminants of concern relies on batch sorption experiments, typically performed at skewed solid-to-liquid ratios. The geophysical method spectral induced polarization (SIP) provides a powerful non-invasive monitoring alternative that can capture changes in soil electrical properties driven by contaminant sorption, yielding an approach whereby immobilization can be monitored in situ. Here, we present SIP signals obtained from a series of columns packed with a water saturated natural sandy-loam soil, with and without solid organic matter (SOM) amendment, contaminated with increasing concentrations of the herbicide paraquat. Our results highlight that soil polarization drops proportional to increasing amounts of sorbed paraquat in the SOM-free soil, exhibiting a Langmuir-type leveling-off behaviour. The addition of 8 percent-SOM yielded an increase in both the real ($\sigma ^{\prime}$) and imaginary ($\sigma ^{\prime\prime}$) conductivity of the uncontaminated treatment, driven by the contribution of charged sites in the SOM. Further, SOM modified the dependence between $\sigma ^{\prime\prime}$ and sorbed paraquat, likely driven by continued polarization within the polydisperse SOM with continued paraquat addition. However, the time constant ($\tau $), derived using the Cole–Cole model, shed light on a saturation-type dependence governed by a drop in ion mobility with increasing sorption. Thus, aiding the interpretation of sorption-driven SIP signals.

In Vitro and In Vivo evaluation of montmorillonite for paraquat poisoning

Evaluation of montmorillonite for paraquat by in vitro and in vivo test. In vitro test were evaluated by a batch test, taking the paraquat concentration, adsorbents, reaction environment and time as indices, the absorption rate was screened by orthogonal design. In vivo test was executed with rabbits. Group 1: 4 rabbits dosed with montmorillonite. Group 2: 8 rabbits dosed with 200 mg/kg paraquat. Group 3: 6 rabbits dosed with 200 mg/kg paraquat then gavage with montmorillonite 5 min later. Group 4: 6 rabbits dosed with 200 mg/kg paraquat then gavage with montmorillonite 30 min later. Blood paraquat concentration, serum cytokines, blood gas analysis and histopathology of lung were implemented. In vitro test found that all the four factors influence the absorption rate of paraquat (P < 0.05). In vitro test found that oral montmorillonite could change toxicokinetics parameters of paraquat (P < 0.05); decrease raised serum TGF-β1 and HMGB1 (P < 0.05) and alleviate the histopathology damage of lung. Montmorillonite might exert its protective effects on paraquat induced damage.

Characterization of Morganella sp. for its Paraquat Degradation Potential

One of the beneficial roles of the microbial population is their ability to convert toxic herbicides to lesser toxic compounds such as water and carbon (IV) oxide. Paraquat which is an acutely toxic herbicide is used on farmlands and has been found to affect human health. This study was aimed at characterizing bacteria with the potential to degrade paraquat. Previously isolated bacteria from culture collection labelled A-F were screened for their potential to degrade and utilized paraquat as the sole carbon source in Bushnell Hass agar media. Of the six isolates, isolate E (Morganella sp.) was observed to have the highest growth and tolerance to paraquat after 72 h of incubation at 37 ºC. Characterization study revealed that Morganella sp. can utilize and grow with optimum conditions of pH 6.5, the temperature of 30 ºC and can tolerate up to 400 mg/L paraquat concentration with an increase in growth as inoculum size increases. Thus, these findings showed that Morganella sp. can degrade toxic paraquat to a less toxic form and therefore can be a good isolate for the future bioremediation process of the pollutant.

Comparison of Paraquat Herbicide Removal from Aqueous Solutions using Nanoscale Zero-Valent Iron-Pumice/Diatomite Composites

Paraquat is the most important herbicide of the bipyridyl group. The aim of the present study was to compare the removal of paraquat herbicide from aqueous solutions using nanoscale zero-valent iron-pumice/diatomite composites. In this study, nZVI was supported with diatomite and pumice. Scanning electron microscopy (SEM) analysis, X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectrometry (FTIR), and specific surface area tests (BET) were used to evaluate the properties of nanoadsorbents. The residual concentration of paraquat in aqueous solution was detected by high-performance liquid chromatography (HPLC). Then, the effects of different variables including the pollutant concentration, contact time, temperature, adsorbents (D-nZVI and P-nZVI) dose, and pH, were investigated in a lab scale batch system. The results showed that the optimal pH for both processes was 3.74. In optimal conditions, the efficiencies of D-nZVI and P-nZVI were 92.76% and 85.28%, respectively. In addition, isotherm and adsorption kinetics studies indicated that P-nZVI follows the Langmuir and Freundlich isotherm models, and D-nZVI follows the Langmuir isotherm model, and both processes follow pseudo-second-order kinetics. The results indicated that the synthesized nanoparticles were suitable for removing paraquat from aqueous solutions. Both adsorbents were found to be very effective in removing similar compounds at ambient temperature in a short time.

Haematological and Histopathological Examinations of African Catfish (Clarias gariepinus) Exposed to Sub-Lethal Concentrations of Paraquat

The study was designed to investigate the sub-lethal effects of paraquat on haematological parameters and histopathology of the gills, skin and liver of Clarias gariepinus juveniles of mean weight (38.26±1.20g) and length (17.50±1.55cm). The fish were exposed to 10, 20, 30, 40 and 50% of the 96hrsLC50 value of 107mg/l estimated from the 96 hours acute toxicity test. Blood samples were collected into heparinized tubes for the analyses of some haematological parameters, while the gills, skin and liver were also removed for histological examinations following standard procedures. The result revealed a significant reduction (P &lt; 0.05) in the values of red blood cells (RBCs), haemoglobin (Hgb), packed cell volume (PCV) and erythrocytes indices from the control. The white blood cells (WBCs) and platelets (Plt) were however increasing significantly (P &lt; 0.05) from those of the control as the test concentrations increased. The histology of the gills revealed some alterations such as epithelial proliferation, vacuolation of the mucus, hyperplasia of epithelial tissue of the gill filament, lifting and necrosis of the secondary lamellae. The exposed skin showed mucous cell proliferation, erosion of the epithelial lining, hypertrophy, necrosis of epithelial cells and widening of the epidermal and dermal layers. The liver exhibited cellular proliferation, sinusoid enlargement, congestion of the central vein, paranchymatous degeneration, vacuolar degeneration, pyknotic nucleic degeneration, legions and necrosis with severity as concentration of paraquat increases. The gills and skin were observed to be the most affected tissues in this study. The study also revealed that paraquat was toxic to C. gariepinus and causes some haematological and histopathological alterations in the fish blood and tissues at concentrations higher than 30mg/l. Therefore, the use of paraquat by farmers should be regulated particularly in area close to the aquatic environment.

INDUCTION OF MACROCYTIC-NORMOCHROMIC ANAEMIA IN Clarias gariepinus –Siluriform- EXPOSED TO SUB-LETHAL CONCENTRATIONS OF 1, 1-DIMETHYL 4, 4-BIPIRIDILLIUM DICHLORIDE (PARAQUAT) UNDER LABPRATORY CONDITIONS

Introduction: Macrocytic-normochromic anaemia was induced in Clarias gariepinus at intervals of 1, 7 and 14 days. Experimental fish were exposed to test water separately diluted with sub-lethal concentrations of paraquat of 0, 0.03, 0.05, 0.07 and 0.09mg/L. 14 days. No in-depth work has been carried out on Macrocytic-normochromic anaemia in Nigeria. Objective: to evaluate macrocytic-normochromic anaemia in Clarias gariepinus exposed to sublethal concentrations of paraquat. Methods: Blood were collected at intervals of 1, 7 and 14 days .Results: Blood dyscrasias was observed with a significant (p&lt;0.05) decrease in haemoglobin, haematocrit, red blood cells, white blood cells, lymphocytes and monocytes. Mean corpuscular volume (MCV), Mean corpuscular haemoglobin (MCH), Neutrophils, Eosinophil and Basophil increased significantly (p&lt;0.05) with increasing concentrations of the toxicant while Mean corpuscular haemoglobin concentration (MCHC) remained normal. Conclusion: Sublethal concentrations of paraquat induced macrocytic-normochromic anaemia in the exposed Clarias gariepinus.

Optimum synthesis of cactus-inspired SERS substrate with high roughness for paraquat detection

Paraquat is a highly effective herbicide and widely used in agricultural production. However, paraquat residue is harmful for human health and can cause irreversible hazard. Thus, it is crucial for monitoring of paraquat residues. In this paper, an efficient SERS platform based on cactus-inspired nanoparticles is proposed for sensitive detection of paraquat. The cactus-liked nanoparticles obtained from one-pot stepwise reduction method possess multiple spiny structures and can produce abundant hot spots, resulting in remarkable SERS performance. SEM, TEM, UV–vis and Raman tests were conducted to characterize and optimize the morphology of cactus-liked nanoparticles under different preparation conditions. The synthesis mechanism and corresponding parameters influence mechanism of cactus-liked nanoparticles were explored in detail. Optimized substrate exhibited a high sensitivity with the detectable concentration of crystal violet (CV) down to 10-9 M and an excellent reproducibility proved by SERS mapping. Furthermore, it behaved good linear relationship with a correlation coefficient (R2) of 96.89% between Raman intensities and concentrations of paraquat, which indicates the SERS substrate prepared with cactus-liked nanoparticles could offer a great potential for identification of paraquat.

Plasma Concentration After the First Hemoperfusion has a High Predictive Value in Medium Level Acute Paraquat-Poisoned Patients.

Paraquat ( PQ) is very poisonous to humans and animals and there is no effective clinical antidote . The efficacy of hemoperfusion (HP) treatment for PQ poisoning remains controversial. To explore new ways to predict the prognosis of patients with acute PQ poisoning and assist in the development of better hemopurification treatment strategies. The clinical data of patients who were intoxicated with PQ through contact were diagnosed with PQ poisoning by high-performance liquid chromatography. Samples were collected by the Emergency Intensive Care Unit of the First Affiliated Hospital of Wenzhou Medical University from January 2012 to November 2016. Based on the prognosis, the patients were grouped into survival and death groups. Comparisons of the differences in the clinical indexes were performed, including the initial concentration of PQ at admission, PQ concentration after first HP, the number of HP cartridges used for the first hemoperfusion, whether HP was combined with continuous renal replacement therapy, and the number of concurrent organ injuries between the 2 groups. In addition, data were analyzed using multivariate logistic regression models and receiver operating characteristic curves. Moreover, prognostic factors in patients with acute PQ poisoning were analyzed. Overall, 128 patients with acute PQ poisoning were enrolled in this study. The median plasma PQ concentrations of the patients at admission were 21 and 834 ng/mL (range: 50-1,099,118 ng/mL). The multiple logistic regression model revealed that the initial concentration of PQ and the PQ concentration after the first perfusion were independent risk factors for death in patients with acute PQ poisoning. The PQ concentration in the survival group after the first HP was <516 ng/mL and was mainly distributed at approximately 100 ng/mL. The percentage of patients whose concentration after the first HP was <516 ng/mL in the death group was only 19%. The initial plasma PQ concentration after admission and PQ concentration after the first HP are risk factors for death in patients with acute PQ poisoning. Moreover, PQ concentration after the first HP had a high predictive value for death. When the initial plasma PQ concentration after admission ranges from 50 ng/mL to 5000 ng/mL, the rapid reduction in plasma PQ concentration after HP treatment could improve the prognosis of patients with acute PQ poisoning.

Identification of the redox-stress signaling threshold (RST): Increased RST helps to delay aging in C. elegans

Reactive oxygen species (ROS) play a dual role since they can be either beneficial or harmful to living systems. With increasing ROS concentrations, the roles of ROS change from advantageous to detrimental. There seems to be a concentration threshold that determines the transition from their advantageous to detrimental effects. If we purposefully increase the threshold, that is, increase the range of ROS that plays an advantageous role, it should be beneficial for individuals. To test this hypothesis, in C. elegans, the effects of oxidative challenge induced by different concentrations of paraquat (PQ) on nematode lifespan were evaluated. We found that there is a maximum level below which redox stress has benefits and named this threshold as "Redox-stress Signaling Threshold (RST)". Furthermore, we found that starvation (or heat stress or exercise) stimuli at early stage in C. elegans could increase the RST, indicating that this value is not fixed and can be increased by the adaptive response. More intriguingly, we found that increasing RST could improve Redox-stress Response Capacity (RRC) and healthspan, suggesting that increasing the RST value through early stimulation will be an effective strategy to delay aging.