Impacts of Fulvic Acid on the Toxicity of the Herbicide Atrazine to Lemna minor.

Fulvic acids (FA) are environmentally prevalent components of dissolved organic carbon. Little research has evaluated their potential influence on the bioavailability of herbicides to non-target aquatic plants. This study evaluated the potential impacts of FA on the bioavailability of atrazine (ATZ) to the aquatic plant Lemna minor. Plants were exposed to 0, 15, 30, 60, 125, and 750 µg/L ATZ in media containing three FA concentrations (0, 5, and 15 mg/L) in a factorial study under static conditions. Fronds were counted after 7- and 14-days exposure and intrinsic growth rates (IGR) and total frond yields were calculated for analysis. Atrazine NOAECs and LOAECs within each FA treatment series (0, 5, or 15 mg/L) were identified and EC50s were estimated. NOAEC/LOAECs for yield and IGR were 60/125 µg/L except for yield in the 0 mg/L-FA series (30/60) and IGR in the 5 mg/L-FA series (30/60). NOAEC/LOAECs were 30/60 µg/L for all treatments and both endpoints after 14 days exposure. EC50s ranged from 88.2 to 106.1 µg/L (frond production 7 DAT), 158.0-186.0 µg/L (IGR, 7 DAT), 74.7-86.3 µg/L (frond production, 14 DAT), and 144.1-151.3 µg/L (IGR, 14 DAT). FA concentrations did not influence the toxicity of ATZ.

Azaphilones from the Endophyte Diaporthe sp. and Their Toxicity.

Chemotherapy and targeted therapies are increasingly used as conventional means to control tumor growth and prolong survival. Patient treated with anti-neoplastic agents experience severe side effects, especially those cytotoxic chemotherapies. Exploring chemo agents with less side effects is the hot spot of anticancer research. In this study, three azaphilone derivatives (chaetoviridin A (1), chaetoviridin E (2) and chaetomugilin D (3)) were isolated from the endophyte of the plant Anoectochilus roxburghii (Wall.) Lindl, their structures were elucidated by NMR. The toxicity of these compounds was evaluated by zebrafish model. The results show that these compounds had no toxicity against zebrafish. These compounds may act as safe anticancer drug leads according to this result. These three azaphilone derivatives were first time reported isolated from Diaporthe species which mainly used to isolate from Chaetomium species.

KIF11, a plus end-directed kinesin, as a key gene in benzo(a)pyrene-induced non-small cell lung cancer.

Evidence indicates that Benzo(a)pyrenediol-epoxide (BPDE) can damage lung cells, resulting in carcinogenesis with complex mechanisms. We aimed to explore the genes and pathway variations in this process. First, the key gene was screened out and identified through data mining, and then, it was in turn validated by bioinformatics analysis and experimental methods. Consequently, 106 up-regulated and 260 down-regulated differentially expressed genes were yielded, which were enriched in various pathways, such as Cell cycle, and p53 signaling pathway. Then, KIF11 was identified as the key gene. Overexpression of KIF11 in lung cancer had a correlation with advanced pathological grade, advanced T stage, and presence of lymph node metastasis, which predicted poor prognosis. In summary, the present study revealed that KIF11 might be a key gene in the tumorigenesis of BPDE-related lung cancer, raising the possibility of KIF11 as a target for BPDE-induced lung cancer prevention and therapy.

RIFM fragrance ingredient safety assessment, 5,8-methano-2H-1-benzopyran, 6(or 7)-ethylideneoctahydro-, [4aR,5S,8S,8aS(or 4aR,5R,8S,8aR)]-rel-, CAS Registry Number 943723-15-7.

The existing information supports the use of this material as described in this safety assessment. 5,8-Methano-2H-1-benzopyran, 6(or 7)-ethylideneoctahydro-, [4aR,5S,8S,8aS(or 4aR,5R,8S,8aR)]-rel- was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog 5,8-methano-2H-1-benzopyran-2-one, 6- ethylideneoctahydro- (CAS # 69486-14-2) show that 5,8-methano-2H-1-benzopyran, 6(or 7)-ethylideneoctahydro-, [4aR,5S,8S,8aS(or 4aR,5R,8S,8aR)]-rel- is not expected to be genotoxic. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the TTC for a Cramer Class III material, and the exposure to 5,8-methano-2H-1-benzopyran, 6(or 7)-ethylideneoctahydro-, [4aR,5S,8S,8aS(or 4aR,5R,8S,8aR)]-rel- is below the TTC (0.0015 mg/kg/day, 0.0015 mg/kg/day, and 0.47 mg/day, respectively). Data provided 5,8-methano-2H-1-benzopyran, 6(or 7)-ethylideneoctahydro-, [4aR,5S,8S,8aS(or 4aR,5R,8S,8aR)]-rel- a NESIL of 8200 µg/cm2 for the skin sensitization endpoint. The phototoxicity/photoallergenicity endpoints were evaluated based on human study data and UV/Vis spectra; 5,8-methano-2H-1-benzopyran, 6(or 7)-ethylideneoctahydro-, [4aR,5S,8S,8aS(or 4aR,5R,8S,8aR)]-rel- is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; 5,8-methano-2H-1-benzopyran, 6(or 7)-ethylideneoctahydro-, [4aR,5S,8S,8aS(or 4aR,5R,8S,8aR)]-rel- was found not to be PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.

Prolonged sub-lethal exposure to galaxolide (HHCB) and tonalide (AHTN) promotes the metastatic potential of glioblastoma tumor spheroids.

Galaxolide and tonalide are well-known polycyclic musks whose intensive use without limitations in numerous cleaning, hygiene, and personal care products has resulted in widespread direct human exposure via absorption, inhalation, and oral ingestion. Latest data shows that long-term, low-dose exposure to toxic chemicals can induce unpredictable harmful effects in a variety of living systems, however, interactions between synthetic musks and brain tumours remain largely unexplored. Glioblastoma (GB) accounts for nearly half of all tumours of the central nervous system and is characterized by very poor prognosis. The aims of this study were (1) to investigate the potential effect of long-term (20-generation) single and combined application of galaxolide and tonalide at sub-lethal doses (5-2.5 u M) on the angiogenesis, invasion, and migration of human U87 cells or tumour spheroids, and (2) to explore the underlying molecular mechanisms. Random amplified polymorphic DNA assays revealed significant DNA damage and increased total mutation load in galaxolide- and/or tonalide-treated U87 cells. In those same groups, we also detected remarkable tumour spheroid invasion and up-regulation of both HIF1-α/VEGF/MMP9 and IL6/JAK2/STAT3 signals, known to have important roles in hypoxia-related angiogenesis and/or proliferation. Prolonged musk treatment further altered angio-miRNA expression in a manner consistent with poor prognosis in GB. We also detected significant over-expression of the genes Slug, Snail, ZEB1, and Vimentin, which are biomarkers of epithelial to mesenchymal transition. In addition, matrigel, transwell, and wound healing assays clearly showed that long-term sub-lethal exposure to galaxolide and/or tonalide induced invasion and migration proposing a high metastatic potential. Our results suggest that assessing expression of HIF-1a, VEGF, STAT3, and the miR-17-92 cluster in biopsy samples of GB patients who have a history of possible long-term exposure to galaxolide or tonalide could be beneficial for deciding a therapy regime. Additionally, we recommend that extensively-used hygiene and cleaning materials be selected from synthetic musk-free products, especially when used in palliative care processes for GB patients.

Decursinol Angelate Arrest Melanoma Cell Proliferation by Initiating Cell Death and Tumor Shrinkage via Induction of Apoptosis.

Melanoma is known to aggressively metastasize and is one of the prominent causes of skin cancer mortality. This study was designed to assess the molecular mechanism of decursinol angelate (DA) against murine melanoma cell line (B16F10 cells). Treatment of DA resulted in growth inhibition and cell cycle arrest at G0/G1 (p < 0.001) phase, evaluated through immunoblotting. Moreover, autophagy-related proteins such as ATG-5 (p < 0.0001), ATG-7 (p < 0.0001), beclin-1 (p < 0.0001) and transition of LC3-I to LC3-II (p < 0.0001) were markedly decreased, indicating autophagosome inhibition. Additionally, DA treatment triggered apoptotic events which were corroborated by the occurrence of distorted nuclei, elevated reactive oxygen species (ROS) levels and reduction in the mitochondrial membrane potential. Subsequently, there was an increase in the expression of pro-apoptotic protein Bax in a dose-dependent manner, with the corresponding downregulation of Bcl-2 expression and cytochrome C expression following 24 h DA treatment in A375.SM and B16F10 cells. We substantiated our results for apoptotic occurrence through flow cytometry in B16F10 cells. Furthermore, we treated B16F10 cells with N-acetyl-L-cysteine (NAC). NAC treatment upregulated ATG-5 (p < 0.0001), beclin-1 (p < 0.0001) and LC3-I to LC3-II (p < 0.0001) conversion, which was inhibited in the DA treatment group. We also noticed a systematic upregulation of important markers for progression of G1 cell phase such as CDK-2 (p < 0.029), CDK-4 (p < 0.036), cyclin D1 (p < 0.0003) and cyclin E (p < 0.020) upon NAC treatment. In addition, we also observed a significant fold reduction (p < 0.05) in ROS fluorescent intensity and the expression of Bax (p < 0.0001), cytochrome C (p < 0.0001), cleaved caspase-9 (p > 0.010) and cleaved caspase-3 (p < 0.0001). NAC treatment was able to ameliorate DA-induced apoptosis and cell cycle arrest to support our finding. Our in vivo xenograft model also revealed similar findings, such as downregulation of CDK-2 (p < 0.0001) and CDK-4 (p < 0.0142) and upregulation of Bax (p < 0.0001), cytochrome C (p < 0.0001), cleaved caspase 3 (p < 0.0001) and cleaved caspase 9 (p < 0.0001). In summary, our study revealed that DA is an effective treatment against B16F10 melanoma cells and xenograft mice model.

Alkaloid and benzopyran compounds of Melicope latifolia fruit exhibit anti-hepatitis C virus activities.

BACKGROUND: New agents for developing alternative or complementary medicine to treat the hepatitis C virus (HCV) are still needed due to high rates of HCV infection globally and the current limitations of available treatments. Treatment of HCV with a combination of direct acting antivirals have been shown to be approximately 90% effective but will be limited in the future due to the emergence of drug resistance and high cost. The leaves of Melicope latifolia have previously been reported to have anti-HCV activity and are a potential source of bioactive compounds for future novel drug development. This study aimed to evaluate the efficacy of the extract of M. latifolia fruit to treat HCV and to isolate its active compounds. METHOD: M. latifolia fruit was extracted using methanol and purified using vacuum liquid chromatography (VLC) and Radial Chromatography. The anti-HCV activity was analyzed using cell culture lines Huh7it-1 and JFH1 (genotype 2a). Time-of-addition and immunoblotting studies were performed to identify the mode of action of the isolated active compounds. The structures of the active compounds were determined using nuclear magnetic resonance (NMR) spectra, UV, IR, and Mass Spectra. RESULTS: Six known compounds were isolated from M. latifolia fruit: O-methyloktadrenolon, alloevodionol, isopimpinellin, alloxanthoxyletin, methylevodionol, and N-methylflindersine. N-methylflidersine was the most active compound with IC50 value of 3.8 µg/ml while methylevodionol, isopimpinellin, and alloevodionol were less active. O-methyloktadrenolon and alloxanthoxyletin were moderately active with IC50 values of 10.9 and 21.72 µg/ml, respectively. N-methylflidersine decreased level of HCV NS3 protein expression in the cells. CONCLUSION: The alkaloid compound, N-methylflindersine which was isolated from M. latifolia possesses anti-HCV activity through post-entry inhibition and suppressed NS3 protein expression.

Potential of environmental concentrations of the musks galaxolide and tonalide to induce oxidative stress and genotoxicity in the marine environment.

Polycyclic musk compounds have been identified in environmental matrices (water, sediment and air) and in biological tissues in the last decade, yet only minimal attention has been paid to their chronic toxicity in the marine environment. In the present research, the clams Ruditapes philippinarum were exposed to 0.005, 0.05, 0.5, 5 and 50 µg/L of the fragrances Galaxolide® (HHCB) and Tonalide® (AHTN) for 21 days. A battery of biomarkers related with xenobiotics biotransformation (EROD and GST), oxidative stress (GPx, GR and LPO) and genotoxicity (DNA damage) were measured in digestive gland tissues. HHCB and AHTN significantly (p < 0.05) induced EROD and GST enzymatic activities at environmental concentrations. Both fragrances also induced GPx activity. All concentrations of both compounds induced an increase of LPO and DNA damage on day 21. Although these substances have been reported as not acutely toxic, this study shows that they might induce oxidative stress and genotoxicity in marine organisms.

Exploration of fulvic acid as a functional excipient in line with the regulatory requirement.

Fulvic acid, a humic substance often considered as a geopolymer, extracted from different natural resources like Shilajit, Peat, dissolved organic matters, etc. There are several reports of its pharmacological properties and its potential as pharmaceutical excipients. So, we have devised a project to strengthen its claim as a functional excipient. For the given project, lyophilized sample of a dietary supplement product (an aqueous solution of peat derived Fulvic acid) was used. The selected studies were typical for an excipient development like physicochemical properties, flow properties, compatibility with other excipient and stability studies, non-clinical safety studies (acute toxicity in mice whereas sub-acute toxicity in rats) and some functionality tests. We also suggest its ability to form co-crystal with natural phytochemicals. Our group has already reported its ability to enhance solubility and or bioavailability of different BCS class II drugs. Henceforth, we can propose that Fulvic acid appears a good candidate to be further explored as a functional excipient and should be evaluated as per the remaining recommendations of IPEC, USFDA, and USP.

Cytotoxic Nitrogenated Azaphilones from the Deep-Sea-Derived Fungus Chaetomium globosum MP4-S01-7.

Eight new nitrogenated azaphilones (1-8) and two known compounds (chaetoviridin A and chaetoviridin E, 9, 10) were isolated from the culture of the deep-sea-derived fungus Chaetomium globosum MP4-S01-7. The absolute configurations of new compounds were elucidated by HSQC-HECADE NMR data, J-based configuration analysis, and modified Mosher's method and finally verified by comparison of recorded and computed NMR chemical shifts from quantum chemical calculations coupled with a statistical procedure (DP4+). All of the compounds were evaluated for their in vitro cytotoxicities against the gastric cancer cell lines MGC803 and AGS, and most of them showed significant inhibition on cancer cell viability at 10 µM. Among them, compounds 1, 2, and 5 exerted the most potent cytotoxic activities, with IC50 values less than 1 µM. Further studies showed that compound 2 inhibited cell cycle progression, and both compounds 1 and 2 induced apoptosis of gastric cancer cells in a concentration-dependent manner.

A Fulvic Acid-like Substance Participates in the Pro-inflammatory Effects of Cigarette Smoke and Wood Smoke Particles.

We tested the postulates that (1) a fulvic acid (FA)-like substance is included in cigarette smoke and wood smoke particles (WSP) and (2) cell exposure to this substance results in a disruption of iron homeostasis, associated with a deficiency of the metal and an inflammatory response. The fluorescence excitation-emission matrix spectra of the water-soluble components of cigarette smoke condensate and WSP (Cig-WS and Wood-WS) approximated those for the standard reference materials, Suwanee River and Nordic fulvic acids (SRFA and NFA). Fourier transform infrared spectra for the FA fraction of cigarette smoke and WSP (Cig-FA and Wood-FA), SRFA, and NFA also revealed significant similarities (O-H bond in alcohols, phenols, and carboxylates, C═O in ketones, aldehydes, and carboxylates, and a significant carboxylate content). After exposure to Cig-WS and Wood-WS and the FA standards, iron was imported by respiratory epithelial cells, reflecting a functional iron deficiency. The release of pro-inflammatory mediators interleukin (IL)-8 and IL-6 by respiratory epithelial cells also increased following exposures to Cig-WS, Wood-WS, SRFA, and NFA. Co-exposure of the respiratory epithelial cells with iron decreased supernatant concentrations of the ILs relative to exposures to Cig-WS, Wood-WS, SRFA, and NFA alone. It is concluded that (1) a FA-like substance is included in cigarette smoke and WSP and (2) respiratory epithelial cell exposure to this substance results in a disruption of iron homeostasis associated with both a cell deficiency of the metal and an inflammatory response.

Garcinoic Acid Is a Natural and Selective Agonist of Pregnane X Receptor.

Pregnane X receptor (PXR) is a master xenobiotic-sensing transcription factor and a validated target for immune and inflammatory diseases. The identification of chemical probes to investigate the therapeutic relevance of the receptor is still highly desired. In fact, currently available PXR ligands are not highly selective and can exhibit toxicity and/or potential off-target effects. In this study, we have identified garcinoic acid as a selective and efficient PXR agonist. The properties of this natural molecule as a specific PXR agonist were demonstrated by the screening on a panel of nuclear receptors, the assessment of the physical and thermodynamic binding affinity, and the determination of the PXR-garcinoic acid complex crystal structure. Cytotoxicity, transcriptional, and functional properties were investigated in human liver cells, and compound activity and target engagement were confirmed in vivo in mouse liver and gut tissue. In conclusion, garcinoic acid is a selective natural agonist of PXR and a promising lead compound toward the development of new PXR-regulating modulators.

Insights into mechanisms of pranoprofen-induced apoptosis and necroptosis in human corneal stromal cells.

Pranoprofen (PPF) is a wildly used anti-inflammatory ophthalmic drug. It was reported that PPF could decrease early epithelialization of scrape wounds in rabbit cornea and could reduce cell activities of cultured human corneal endothelial cells. However, effects of PPF on corneal stromal cells playing important roles in corneal wound healing remain unknown. In this study,in vitro model of cultured human corneal stomal (HCS) cells and in vivo model of rabbit corneas were used to investigate the effects and underlying mechanisms of PPF. Our findings showed that high concentrations of PPF treatment (0.1 % to 0.0125 %) caused limited chromatin condensation and quickly decreased cell viability that was proved to initiate necroptosis in HCS cells through activating receptor interacting protein kinase (RIPK) and mixed lineage kinase domain-like (MLKL). While low concentrations of PPF treatment (0.00625 %) induced DNA fragmentation, apoptotic body formation, ROS generation, activation of caspases and increase in cytoplasmic content of Bad, Bax and cytoplasmic cytochrome c that suggested apoptosis happened through ROS-mediated caspase-dependent and caspase-independent pathways. Studies of rabbit corneas treated with 0.1 % PPF (the clinical concentration) showed that PPF could induce apoptosis of rabbit corneal stromal cells. This work would be helpful for better understanding cytotoxic effects PPF on human corneal cells.

Identifying bioaccessible suspect toxicants in sediment using adverse outcome pathway directed analysis.

Chemical mixtures are a common occurrence in contaminated sediment and determining causal relationship between sediment contamination and adverse outcomes is challenging. The bioavailability and choice of bioassay endpoints played important roles in elucidating causality. As such, bioaccessibility-based XAD extraction and adverse outcome pathway (AOP) guided bioassays were incorporated into an effect-directed analysis to more effectively determine sediment causality. XAD extracts of sediments from urban waterways in Guangzhou, China were examined using cell viability bioassays with four human tumor cells from lung, liver, breast, and bone marrow. Pronounced effects to SH-SY5Y cells were noted, thus neurotoxicity was subsequently focused in the AOP-guided bioassays. Intracellular calcium influx, mitochondrial membrane potential inhibition, reactive oxygen species generation, and cell viability were utilized as evidence for neurotoxicity AOP-guided analysis. Suspect toxicants were identified in active fractions using GC-MS. Toxicity confirmation was performed by evaluating toxicity contributions of the candidates to the pathway. Cypermethrin, bisphenol A, galaxolide, tonalide, and versalide were found as the major stressors across key events of the studied pathway. Moreover, good correlations among key events validated the feasibility of method to predict in vivo response, suggesting that considering bioavailability and AOP improved environmental relevance for toxicant identification in a complex mixture.

Algal toxicity, accumulation and metabolic pathways of galaxolide.

Galaxolide (HHCB) is known to be persistent during wastewater treatment and has raised increasing concern due to its high detection frequency in the environment and potentially negative effects. However, little information is available on the degradation of HHCB by algae, the degradation mechanisms and the toxicity of HHCB on algae. In the present study, HHCB was found to be toxic to Navicula sp. and Scenedesmus quadricauda, with a 3 d EC50 of 0.050 and 0.336 mg L-1, respectively. Both microalgae showed high removal efficiency (72.9-100%) for HHCB. S. quadricauda showed a more satisfactory effect in the bioremediation of HHCB than Navicula sp. A total of four metabolites were found in the biotransformation processes of HHCB, and its possible metabolic pathways were proposed. Hydroxylation, methoxylation, methylation, ketonization, demethylation, and oxaloacetate conjunction contributed to the metabolism of HHCB in algal cells.

A Unique Approach to Development of a Multiratiometric Fluorescent Composite Probe for Multichannel Bioimaging.

Ratiometric fluorescent probes have shown great potential for optical sensing and have been widely used for bioimaging. However, due to extremely stringent molecular design, most conventional organic ratiometric fluorescent probes can only achieve one single ratio. Currently, the detection of a target in living systems in a multiratiometric manner is prominently challenging. Therefore, it is of great significance to develop a method to construct the multiratiometric fluorescent probes for accurate quantitative detection of specific small molecules. To address this challenge, we developed a unique multiratiometric composite fluorescent probe. Herein, a new triple-ratiometric fluorescent composite nanoprobe CP@GQDs-OH based on OH-functionalized GQDs (GQDs-OH) and red emission ratiometric fluorescent molecular probe (CP) was prepared through π-π stacking. The novel nanoprobe showed high selectivity for SO2 with three linear ratio changes. Significantly, CP@GQDs-OH was successfully applied for the detection of SO2 in the living cells and zebrafishes by the unprecedented triple-ratiometric fashion.

A highly selective and ultrafast near-infrared fluorescent turn-on and colorimetric probe for hypochlorite in living cells.

Hypochlorous acid (HOCl)/hypochlorite (OCl-), important reactive oxygen species, play essential roles in many physiological and pathological progresses. Accordingly, we developed a novel dicyanomethylene-4H-pyran (DCM)-based probe DCM-OCl for colorimetric and near-infrared fluorescent turn-on detection of OCl-. The probe exhibited excellent selectivity and sensitivity for OCl- over other bio-related analytes with a detection limit of 80 nM. The excellent selectivity of DCM-OCl for OCl- was ascribed to specific oxidative cleavage of the dimethylthiocarbamate (DMTC) recognition unit by OCl-. Moreover, DCM-OCl exhibited an ultrafast turn-on response (<3 s) to OCl-, potentially allowing real-time detection of OCl-. Furthermore, DCM-OCl was successfully used to image endogenous/exogenous OCl- in living cells.

Detection of DNA damage formation by natural organic matter using EGFP-fused MDC1-expressing cells.

Studies have been conducted on the genotoxicity and carcinogenicity of disinfection by-products formed from natural organic matter (NOM) and mitigation effect for mutagens and clastogens by NOM. Whereas, reportedly, synthetic humic acid in high concentration has induced genotoxicity in human cells, and NOM samples have provoked mild oxidative and other physiological responses in aquatic organisms. Our group developed a novel detection method for DNA damage formation, namely enhanced green fluorescent protein (EGFP)-fused mediator of DNA damage checkpoint 1 (MDC1)-expressing human cells as simple and high-sensitive system. By using this method, a significant increase in the foci area was observed after 3 h, but not 24 h for 130 mgC L-1 Suwannee River fulvic acid (SRFA), 38 mgC L-1 humic acid (SRHA), and 19 mgC L-1 NOM (SRNOM). The SRNOM concentration is the original environmental one; therefore, it was suggested that the formation and repair of DNA damage associated with γ-H2AX, a biomarker for DNA double-strand breaks by mild oxidative stress, in Suwannee River (SR) were detected for the first time. The increase in the foci area was not observed for 18 mgC L-1 Lake Biwa fulvic acid (LBFA) and 50 mg L-1 catechin after both 3 h and 24 h. The difference between the SR and Lake Biwa (LB) samples may result from the differences in their electron-accepting capacity. The application of this methodology is expected to elucidate oxidative stress and toxicological effects shortly and in detail for many water samples.

Avoidance behaviour of the shrimp Palaemon varians regarding a contaminant gradient of galaxolide and tonalide in seawater.

The musk fragrances galaxolide (HHCB) and tonalide (AHTN) are compounds of emerging concern that have been found in various environmental compartments. The present study addressed the ability of HHCB and AHTN to elicit the avoidance response in the estuarine shrimp Palaemon varians and to predict the population immediate decline (PID) of P. varians when exposed to HHCB and AHTN by integrating both avoidance (non-forced exposure) and lethality (forced exposure) responses. The avoidance response was tested in a non-forced multi-compartmented static system, in which the shrimps could move freely among the compartments with different concentrations. The shrimps (n = 3 shrimps per compartment/concentration; 18 shrimps per system) were exposed to a gradient (0, 0.005, 0.05, 0.5, 5 and 50 µg/L) of both substances and their positions were checked at every 20 min for a 3 h period. The results from 24-h forced exposure showed no dose-response relationship and the highest percentage mortality was 17% for HHCB at 0.005 and 0.5 µg/L. In the 3-h non-forced exposure to a gradient of HHCB and AHTN, significant concentration-dependent spatial avoidance was observed for both substances. The shrimps avoided the lowest concentration of HHCB and AHTN (0.005 µg/L) by 15% and 16%. The avoidance increased significantly (p < 0.005) to a 61% and 57%, respectively, for the highest concentration (50 µg/L). The population immediate decline was driven by the avoidance behaviour of the shrimps rather than mortality. These results indicated that the aversiveness of HHCB and AHTN might have serious consequences for habitat selection processes by organisms.

Biochemical and toxicological investigation of karanjin, a bio-pesticide isolated from Pongamia seed oil.

Karanjin, a furanoflavonol from Pongamia pinnata L is used in agricultural practices for its pesticidal, insecticidal and acaricidal activities. It is commercially available as a bio-pesticide targeting a wide variety of pests. The present study was intended to evaluate the biochemical interactions of karanjin with bovine serum albumin (BSA) and study its toxicological effects on mammalian and bacterial cell lines. Karanjin bound to BSA at a single site with a dissociation constant of 19.7 µM. Evaluation of BSA-karanjin interactions at three different temperatures indicated the involvement of static mode of quenching. Binding experiments in the presence of warfarin and computational docking analysis indicated that karanjin bound closer to the warfarin binding site located in the Subdomain IIA of BSA. Using Förster resonance energy transfer analysis the distance between TRP 213 of BSA and karanjin was found to be 20 Å. Collective results from synchronous fluorescence spectra analysis, differential scanning calorimetry, and circular dichroism analysis indicated that binding of karanjin induced conformational changes in the secondary structure of BSA. Karanjin exhibited low toxicity against human cervical cancer cells and normal mouse fibroblast L929 cells and modestly inhibited the growth of B. subtilis and E. coli cells. The data presented in this study provides insights for understanding the binding interactions of karanjin with BSA and its possible toxicological effects on mammalian cell lines and bacteria.