Unveiling the ecotoxicological effects of azoxystrobin-based fungicides at realistic concentrations on the land snail, Theba pisana.

The ecotoxicological consequences of azoxystrobin on land snails have not yet been addressed. Therefore, the present study aims to provide novel data on the threat of a commercial grade azoxystrobin (AMISTAR) at two environmentally relevant concentrations (0.3 µg/ml) and tenfold (3 µg/ml) on the model species, Theba pisana by physiological, biochemical, and histopathological markers for 28 days. Our results showed a reduction in animal food consumption and growth due to exposure to both azoxystrobin concentrations. It also induced oxidative stress and led to a significant decrease in lipid peroxidation (LPO) levels after 7 days of exposure, while the opposite effect occurred after 28 days. Except for the 7-day exposure, all treated snails had significantly reduced glutathione (GSH) content and increased catalase (CAT) activity at all-time intervals. Glutathione peroxidase (GPx), glutathione-S-transferase (GST) activities, and protein content (PC) were elevated in treated snails at all-time intervals. Moreover, alterations in acetylcholinesterase (AChE) activity between a decrease and an increase were noticed. Additionally, azoxystrobin exerted changes in T. pisana hepatopancreas architecture. Our study suggests that azoxystrobin may have negative ecological consequences for T. pisana and highlights its potential risks to the natural environment.

How to Overcome a Snail? Identification of Putative Neurotoxins of Snail-Feeding Firefly Larvae (Coleoptera: Lampyridae, Lampyris noctiluca).

The larvae of some lampyrid beetles are highly specialized predators of snails. They have been observed to climb on the shells of their prey and use this exposed position to bite and inject secretions potentially originating from the midgut. Besides serving the purpose of extra-oral digestion (EOD), injected compounds also seem to have a paralyzing effect. Up to now, the toxins causing this paralyzing activity have not been identified. In the current study, we provide a first compositional analysis of the midgut secretion from lampyrid larvae, with a focus on identifying putative neurotoxins causing the observed paralyzing effect. For this purpose, we utilized a combined proteo-transcriptomic approach to characterize the compounds present in the midgut secretion of larval stages of Lampyris noctiluca. In terms of the absolute numbers of identified compounds, the midgut secretion is dominated by hydrolyzing enzymes comprising peptidases, carboxylesterases, and glycosidases. However, when considering expression levels, a few rather short cysteine-rich peptides exceed all other compounds. Some of these compounds show moderate similarity to putative neurotoxins identified in the venom of other arthropods and could be responsible for paralyzing effects. In addition to these potential toxins, we provide a list of peptides typical of the midgut secretion of L. noctiluca, supplemented by the corresponding precursor sequences.

Effects of arsenic on gut microbiota and its bioaccumulation and biotransformation in freshwater invertebrate.

This study aimed to investigate the impact of arsenic stress on the gut microbiota of a freshwater invertebrate, specifically the apple snail (Pomacea canaliculata), and elucidate its potential role in arsenic bioaccumulation and biotransformation. Waterborne arsenic exposure experiments were conducted to characterize the snail's gut microbiomes. The results indicate that low concentration of arsenic increased the abundance of gut bacteria, while high concentration decreased it. The dominant bacterial phyla in the snail were Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteriota. In vitro analyses confirmed the critical involvement of the gut microbiota in arsenic bioaccumulation and biotransformation. To further validate the functionality of the gut microbiota in vivo, antibiotic treatment was administered to eliminate the gut microbiota in the snails, followed by exposure to waterborne arsenic. The results demonstrated that antibiotic treatment reduced the total arsenic content and the proportion of arsenobetaine in the snail's body. Moreover, the utilization of physiologically based pharmacokinetic modeling provided a deeper understanding of the processes of bioaccumulation, metabolism, and distribution. In conclusion, our research highlights the adaptive response of gut microbiota to arsenic stress and provides valuable insights into their potential role in the bioaccumulation and biotransformation of arsenic in host organisms. ENVIRONMENTAL IMPLICATION: Arsenic, a widely distributed and carcinogenic metalloid, with significant implications for its toxicity to both humans and aquatic organisms. The present study aimed to investigate the effects of As on gut microbiota and its bioaccumulation and biotransformation in freshwater invertebrates. These results help us to understand the mechanism of gut microbiota in aquatic invertebrates responding to As stress and the role of gut microbiota in As bioaccumulation and biotransformation.

Biomineralization biomarkers to assess microplastics toxic effects in the freshwater snail Pomacea canaliculata.

Microplastics (MPs) pollution has increased the number of reports on the toxic effects on biota, especially aquatic organisms. Recently, studies highlighted changes in ion transport and concentration, especially Ca2+, in organisms exposed to MPs. For calcifying organisms, such as mollusks, Ca2+ homeostasis is critical for their shells construction. We investigated the effects of polyethylene (PE) MPs at 20 µg/L on biomineralization biomarkers (Ca2+ATPase, carbonic anhydrase, hemolymph [Ca2+], and shell regeneration) of the freshwater gastropod Pomacea canaliculata. Two experimental sets were performed: (1) animals in physiological condition and (2) animals with their shells excised. The results of the first set showed that within 24 h, the hemolymph [Ca2+] decreased, and the Ca2+ATPase activity increased in the mantle edge. For carbonic anhydrase (CA), the activity decreased in the gland and increased in the mantle. By 72 h, the hemolymph [Ca2+] had not changed, whereas both enzymes had increased in both tissues. In the second set, the hemolymph [Ca2+] increased after 72 h, whereas Ca2+ATPase activity decreased in both tissues. For AC, the opposite results were observed. At 120 h, calcium pumping was still reduced and CA values increased in the digestive gland. Additionally, MPs exposure increased the capacity of the gastropods to recover their shells. Based on this, our work provides novel data associating PE microplastic exposures (at 20 µg/L) and their potential to stimulate biomineralization enzymes of P. canaliculata, as well as increase shell regeneration in excised animal; a good prerogative for further investigations on both subjects that still lacks of more robust evidence.

Combined toxic effects of environmental predominant microplastics and ZnO nanoparticles in freshwater snail Pomaceae paludosa.

In the past few years, microplastics are one of the ubiquitous threatening pollutants in aquatic habitats. These persistent microplastics interact with other pollutants, especially nanoparticles were adherent on the surface, which causes potential hazards in the biota. In this study, the toxic effects of individual and combined (28 days) exposure with zinc oxide nanoparticles and polypropylene microplastics were assessed in freshwater snail Pomeacea paludosa. After the experiment, the toxic effect was evaluated by the estimation of vital biomarkers activities including antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), oxidative stress in carbonyl protein (CP), lipid peroxidation (LPO), and digestive enzymes (esterase and alkaline phosphatase). Chronic exposure to pollutants in snails causes increased reactive oxygen species level (ROS) and generates free radicals in their body which leads to impairment and alterations of biochemical markers. Where alteration in acetylcholine esterase (AChE) activity and decreased digestive enzymes (esterase and alkaline phosphatase) activities were observed in both individual and combined exposed groups. Further, histology results revealed the reduction of haemocyte cells, the disintegration of blood vessels, digestive cells, calcium cells, and DNA damage was also detected in the treated animals. Overall, when compared to individual exposures, combined exposure of pollutants (zinc oxide nanoparticles and polypropylene microplastics) causes more serious harms including decline and increased antioxidant enzyme parameters, damage the protein and lipids by oxidative stress, increased neurotransmitter activity, decrease digestive enzyme activities in the freshwater snail. The outcome of this study concluded that polypropylene microplastics along with nanoparticles cause severe ecological threats and physio-chemical effects on the freshwater ecosystem.

Studies on a widely-recognized snail model species (Lymnaea stagnalis) provide further evidence that vertebrate steroids do not have a hormonal role in the reproduction of mollusks.

Experiments were carried out to determine whether, as with other mollusks that have been studied, the snail, Lymnaea stagnalis, can absorb, esterify and store vertebrate steroids that are present in the water. We also carried out experiments to determine whether neural tissues of the snail could be immunohistochemically stained with an antibody to human aromatase (a key enzyme that catalyzes the conversion of testosterone [T] to 17ß-estradiol [E2]); and, if so, to determine the significance of such staining. Previous studies on other mollusks have reported such staining and have proposed this as decisive evidence that mollusks have the same steroid synthesis pathway as vertebrates. We found that snails absorb, esterify and retain esterified T, E2, progesterone and ethinyl-estradiol (albeit with an absorption rate about four times slower, on a weight basis, than the mussel, Mytilus edulis). We also found that not only anti-human aromatase, but also anti-human nuclear progesterone receptor (nPR) and anti-human gonadotropin-releasing hormone antibodies immunohistochemically stained snail neural cells. However, further experiments, involving gel electrophoretic separation, followed by immunostaining, of proteins extracted from the neural tissue, found at least two positively-stained bands for each antibody, none of which had masses matching the human proteins to which the antibodies had been raised. The anti-aromatase antibody even stained the 140 kDA ladder protein used as a molecular weight marker on the gels. Mass spectrometric analysis of the bands did not find any peptide sequences that corresponded to the human proteins. Our findings confirm that the presence of vertebrate-like sex steroids in molluscan tissues is not necessarily evidence of endogenous origin. The results also show that immunohistochemical studies using antibodies against human proteins are grossly non-specific and likely to have little or no value in studying steroid synthesis or activity in mollusks. Our conclusions are consistent with the fact that genes for aromatase and nPR have not been found in the genome of the snail or of any other mollusk. Our overarching conclusion, from this and our previous studies, is that the endocrinology of mollusks is not the same as that of humans or any other vertebrates and that continuing to carry out physiological and ecotoxicological studies on mollusks on the basis of this false assumption, is an unconscionable waste of resources.

The T-1 conotoxin µ-SrVA from the worm hunting marine snail Conus spurius preferentially blocks the human NaV1.5 channel.

Conotoxin sr5a had previously been identified in the vermivorous cone snail Conus spurius. This conotoxin is a highly hydrophobic peptide, with the sequence IINWCCLIFYQCC, which has a cysteine pattern "CC-CC" belonging to the T-1 superfamily. It is well known that this superfamily binds to molecular targets such as calcium channels, G protein-coupled receptors (GPCR), and neuronal nicotinic acetylcholine receptors (nAChR) and exerts an effect mainly in the central nervous system. However, its effects on other molecular targets are not yet defined, suggesting the potential of newly relevant molecular interactions. To find and demonstrate a potential molecular target for conotoxin sr5a electrophysiological assays were performed on three subtypes of voltage-activated sodium channels (NaV1.5, NaV1.6, and NaV1.7) expressed in HEK-293 cells with three different concentrations of sr5a(200, 400, and 600 nM). 200 nM sr5a blocked currents mediated by NaV1.5 by 33%, NaV1.6 by 14%, and NaV1.7 by 7%. The current-voltage (I-V) relationships revealed that conotoxin sr5a exhibits a preferential activity on the NaV1.5 subtype; the activation of NaV1.5 conductance was not modified by the blocking effect of sr5a, but sr5a affected the voltage-dependence of inactivation of channels. Since peptide sr5a showed a specific activity for a sodium channel subtype, we can assign a pharmacological family and rename it as conotoxin µ-SrVA.

A Novel Dimeric Conotoxin, FrXXA, from the Vermivorous Cone Snail Conus fergusoni, of the Eastern Pacific, Inhibits Nicotinic Acetylcholine Receptors.

We isolated a new dimeric conotoxin with inhibitory activity against neuronal nicotinic acetylcholine receptors. Edman degradation and transcriptomic studies indicate a homodimeric conotoxin composed by two chains of 47 amino acid in length. It has the cysteine framework XX and 10 disulfide bonds. According to conotoxin nomenclature, it has been named as αD-FrXXA. The αD-FrXXA conotoxin inhibited the ACh-induced response on nAChR with a IC50 of 125 nM on hα7, 282 nM on hα3ß2, 607 nM on α4ß2, 351 nM on mouse adult muscle, and 447 nM on mouse fetal muscle. This is first toxin characterized from C. fergusoni and, at the same time, the second αD-conotoxin characterized from a species of the Eastern Pacific.

Snail Mucus Enhances Chemosensitivity of Triple-negative Breast Cancer Via Activation of the Fas Pathway.

BACKGROUND/AIM: The poor prognosis and chemoresistance of patients with triple-negative breast cancer (TNBC) urge the development of new therapeutic strategies. Snail mucus has shown its ability against inflammation, a process closely related to tumorigenesis, suggesting a potential anti-cancer activity. MATERIALS AND METHODS: The effect and mechanisms of snail mucus on cell viability were determined by IncuCyte Live-cell analysis and molecular biological methods. The anti-cancer fractions of snail mucus were isolated and identified by medium pressure liquid chromatography (MPLC) and nuclear magnetic resonance (NMR) spectrometry analysis. RESULTS: Snail mucus significantly decreased the viability of TNBC cells with relatively lower cytotoxicity to normal breast epithelial cells and enhanced their response to chemotherapy through activation of Fas signaling by suppressing nucleolin. Two peptide fractions have been identified as the anti-cancer ingredients of the snail mucus. CONCLUSION: Snail mucus can induce programmed cell death via the extrinsic apoptotic pathway and has therapeutic potential by achieving a chemo-sensitizing effect in TNBCs.

Responsiveness of metallothionein and hemocyanin genes to cadmium and copper exposure in the garden snail Cornu aspersum.

Terrestrial gastropods express metal-selective metallothioneins (MTs) by which they handle metal ions such as Zn2+ , Cd2+ , and Cu+ /Cu2+ through separate metabolic pathways. At the same time, they depend on the availability of sufficient amounts of Cu as an essential constituent of their respiratory protein, hemocyanin (Hc). It was, therefore, suggested that in snails Cu-dependent MT and Hc pathways might be metabolically connected. In fact, the Cu-specific snail MT (CuMT) is exclusively expressed in rhogocytes, a particular molluscan cell type present in the hemocoel and connective tissues. Snail rhogocytes are also the sites of Hc synthesis. In the present study, possible interactions between the metal-regulatory and detoxifying activity of MTs and the Cu demand of Hc isoforms was explored in the edible snail Cornu aspersum, one of the most common European helicid land snails. This species possesses CdMT and CuMT isoforms involved in metal-selective physiological tasks. In addition, C. aspersum expresses three different Hc isoforms (CaH ɑD, CaH ɑN, CaH ß). We have examined the effect of Cd2+ and Cu2+ exposure on metal accumulation in the midgut gland and mantle of C. aspersum, testing the impact of these metals on transcriptional upregulation of CdMT, CuMT, and the three Hc genes in the two organs. We found that the CuMT and CaH ɑD genes exhibit an organ-specific transcriptional upregulation in the midgut gland of Cu-exposed snails. These results are discussed in view of possible interrelationships between the metal-selective activity of snail MT isoforms and the synthesis and metabolism of Hc isoforms.

Bioactive Compounds from Marine Heterobranchs.

The natural products of heterobranch molluscs display a huge variability both in structure and in their bioactivity. Despite the considerable lack of information, it can be observed from the recent literature that this group of animals possesses an astonishing arsenal of molecules from different origins that provide the molluscs with potent chemicals that are ecologically and pharmacologically relevant. In this review, we analyze the bioactivity of more than 450 compounds from ca. 400 species of heterobranch molluscs that are useful for the snails to protect themselves in different ways and/or that may be useful to us because of their pharmacological activities. Their ecological activities include predator avoidance, toxicity, antimicrobials, antifouling, trail-following and alarm pheromones, sunscreens and UV protection, tissue regeneration, and others. The most studied ecological activity is predation avoidance, followed by toxicity. Their pharmacological activities consist of cytotoxicity and antitumoral activity; antibiotic, antiparasitic, antiviral, and anti-inflammatory activity; and activity against neurodegenerative diseases and others. The most studied pharmacological activities are cytotoxicity and anticancer activities, followed by antibiotic activity. Overall, it can be observed that heterobranch molluscs are extremely interesting in regard to the study of marine natural products in terms of both chemical ecology and biotechnology studies, providing many leads for further detailed research in these fields in the near future.

A turripeptide from Polystira nobilis venom inhibits human α3ß2 and α7 nicotinic acetylcholine receptors.

Almost all marine snails within superfamily Conoidea produce venoms containing numerous neuroactive peptides. Most toxins characterized from members of this superfamily are produced by species belonging to family Conidae. These toxins (conotoxins) affect diverse membrane proteins, such as voltage- and ligand-gated ion channels, including nicotinic acetylcholine receptors (nAChRs). Family Turridae has been considerably less studied than their Conidae counterpart and, therefore, turrid toxins (turritoxins) have just been barely described. Consequently, in this work the most prominent chromatographic (RP-HPLC) fractions from the East Pacific species Polystira nobilis venom duct extract were isolated. The biological activity of six selected fractions was assayed on human (h) α7 AChRs expressed in Xenopus laevis oocytes. One of these fractions, F21, inhibited the acetylcholine-elicited response by 62 ± 12%. Therefore, this fraction was further purified and the F21-2 peptide was obtained. This peptide (at 5.6 µM) strongly and irreversibly inhibited the acetylcholine-induced response on hα7 and hα3ß2 nAChRs, by 55 ± 4 and 91 ± 1%, respectively. Electrospray mass spectrometry indicates that the average molecular mass of this toxin is 12 358.80 Da. The affinity for hα3ß2 nAChRs is high (IC50 of 566.2 nM). A partial sequence without cysteines was obtained by automated Edman degradation: WFRSFKSYYGHHGSVYRPNEPNFRSFAS…; blastp search revealed that this sequence has low similarity to some non-Cys-containing turripeptides. This is the first report of a turritoxin from a species of the American Pacific and the second description of a turripeptide inhibiting nAChRs.

Ecotoxicology and environmental safety toxicity of pyrethroid cypermethrin on the freshwater snail Chilina parchappii: Lethal and sublethal effects.

The aim of the present work was to study the effect of the pyrethroid cypermethrin (CYP) on the non-target freshwater snail Chilina parchappi. Initially, the sensitivity of adult snails to CYP was evaluated via the 96-h LC50 test. Then, snails were exposed to subtethal CYP concentrations (0.1 and 10 mg/l) for 1, 4 and 10 days and the digestive glands were dissected for biomarkers analyses. Enzymatic activity of catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), as well as total glutathione reduced (GSH) levels, were determined. Histological analyses of morphology, intracellular accumulation of lipofucsins and neutral lipids accumulation in the digestive gland were also evaluated. As compared to other molluscs, C. parchappi showed high resistance to CYP exposure evidenced by the 96-h LC50 value (44.59 mg/l). Snails exposed to sublethal CYP concentrations showed a statistically significant increase (p < 0.01) in GST (79-116%) and GPx (45-190%) activities with respect to controls. However, CAT activity showed a tendency to decrease with CYP treatment but was not statistically significantly different compared to control. Only high CYP concentration caused a statistically significant increase (p < 0.01) in GSH content (95-196%). There was evidence of structural changes in the digestive gland of snails exposed to CYP, showing a dose-dependent response. In exposed snails, some of the main symptoms included a reduction in the thickness of the epithelium, vacuolisation of the digestive cells and an increase in the number of excretory cells. Accumulation of lipofuscins (933-1006%) and neutral lipids (403%) were statistically significantly higher (p < 0.05) in snails exposed to CYP compared to control. This study showed that C. parchappii is quite tolerant to CYP exposure and that at sublethal concentrations, GSH metabolism could play a protective role against the pesticide harm in snails. Therefore, it would be interesting to study the response of this organism to other environmental stressors to assess its potential use in monitoring programs.

Preliminary investigation demonstrating the GHITM gene probably involved in apoptosis and growth of the golden apple snail (Pomacea canaliculata).

BACKGROUND: Growth hormone inducible transmembrane protein (GHITM) is a highly conserved transmembrane protein. This study was conducted to investigate the role of GHITM gene in the apoptosis and growth of the golden apple snail Pomacea canaliculate. RESULTS: The complete cDNA of this gene was cloned using the rapid amplification of cDNA ends (RACE) method and subjected to bioinformatics analysis. The full-length cDNA was 2242 bp, including an open reading frame of 1021 bp that encoded a protein of 342 amino acid residues. The mRNA expression profiles of GHITM gene in different tissues (liver, kidney, gonad and foot) and different growth phases (6-months old and 2-years old) showed that it was expressed in various tissues and different growth phases. Silencing of the GHITM gene by RNAi (RNA interference) experiments revealed that the GHITM gene possibly plays a role in inhibiting apoptosis through detecting the Caspase (Cysteine-requiring Aspartate Protease)-3 activity. In addition, the aperture width and body whorl length of the snail was significantly affected by RNAi, suggesting that this gene plays a significant role in promoting the growth of the organism. CONCLUSIONS: These results demonstrated that the GHITM gene was involved in apoptosis and growth in golden apple snail.

Conformational dynamics of [Formula: see text]-conotoxin PnIB in complex solvent systems.

Cone snails are slow-moving animals that secure survival by injecting to their prey a concoction of highly potent and stable neurotoxic peptides called conotoxins. These small toxins (~ 10-30 AA) interact with ion channels and their diverse structures account for various variables such as the environment and the prey of preference. This study probed the conformational space of α-conotoxin PnIB from Conus pennaceus by performing all-atom molecular dynamics simulations on the conotoxin in complex solvent systems of water and octanol. Secondary structure analyses showed a uniform conformation for the pure (C100Oc, C100W) and minute (C95Oc, C5Oc) systems. In C50Oc, however, structural changes were observed. The original helices were converted to turns and were shown to happen simultaneously with the elongation of the helix and shortening of end-to-end distance. The transitions complement the orientation of the peptide at the interface. The shift to the broken helix conformation is marked by the rearrangement of solvent molecules to a framework that favors the accumulation of water molecules at residues 6-11 of the H2 region. This promotes specific protein-solvent interactions that facilitate secondary structure transitions. As PnIB has shown favorable binding toward neuronal nicotinic acetylcholine receptors, this study may provide insights on this conotoxin's therapeutic potential. Description: Structural changes in PnIB are accompanied by a simultaneous change in solvent density.

Cadmium Pathways in Snails Follow a Complementary Strategy between Metallothionein Detoxification and Auxiliary Inactivation by Phytochelatins.

Metal detoxification is crucial for animals to cope with environmental exposure. In snails, a pivotal role in protection against cadmium (Cd) is attributed to metallothioneins (MTs). Some gastropod species express, in a lineage-specific manner, Cd-selective MTs devoted exclusively to the binding and detoxification of this single metal, whereas other species of snails possess non-selective MTs, but still show a high tolerance against Cd. An explanation for this may be that invertebrates and in particular snails may also synthetize phytochelatins (PCs), originally known to be produced by plants, to provide protection against metal or metalloid toxicity. Here we demonstrate that despite the fact that similar mechanisms for Cd inactivation exist in snail species through binding of the metal to MTs, the actual detoxification pathways for this metal may follow different traits in a species-specific manner. In particular, this depends on the detoxification capacity of MTs due to their Cd-selective or non-specific binding features. In the terrestrial slug Arion vulgaris, for example, Cd is solely detoxified by a Cd-selective MT isoform (AvMT1). In contrast, the freshwater snail Biomphalaria glabrata activates an additional pathway for metal inactivation by synthesizing phytochelatins, which compensate for the insufficient capacity of its non-selective MT system to detoxify Cd. We hypothesize that in other snails and invertebrate species, too, an alternative inactivation of the metal by PCs may occur, if their MT system is not Cd-selective enough, or its Cd loading capacity is exhausted.

Glycyrrhizin Attenuates the Process of Epithelial-to-Mesenchymal Transition by Modulating HMGB1 Initiated Novel Signaling Pathway in Prostate Cancer Cells.

High mobility group box 1 (HMGB1) is upregulated in nearly every tumor type. Importantly, clinical evidence also proposed that HMGB1 is particularly increased in metastatic prostate cancer patients. Besides, a growing number of studies highlighted that HMGB1 could be a successful therapeutic target for prostate cancer patients. Glycyrrhizin is a novel pharmacological inhibitor of HMGB1 that may repress prostate cancer metastasis. This research was aimed to investigate the effect of glycyrrhizin on inhibition of HMGB1-induced epithelial-to-mesenchymal transition (EMT), a key step of tumor metastasis, in prostate cancer cells. In this study, HMGB1 knock-downed DU145 prostate cancer cells were used. Silencing the HMGB1 gene expression triggered a change of cell morphology to a more epithelial-like shape, which was accompanied by a reduction of Cdc42/GSK-3ß/Snail and induction of E-cadherin levels estimated by immunoblotting. Furthermore, HMGB1 facilitated cell migration and invasion via downstream signaling, whereas HMGB1 targeting by 10 mM ethyl pyruvate effectively inhibited EMT characteristics. Interestingly, cell migration capacity induced by HMGB1 in DU145 cells was abolished in a dose-dependent effect of 25-200 µM glycyrrhizin treatment. In conclusion, glycyrrhizin successfully inhibited HMGB1-induced EMT phenomenon, which suggested that glycyrrhizin may serves as a therapeutic agent for metastatic prostate cancer.

Short-term effects of very low dose cadmium feeding on copper, manganese and iron homeostasis: A gastropod perspective.

The available information on the interplay between low-dose cadmium intake and copper, manganese, and iron homeostasis in invertebrates is limited. We have currently studied the accumulation of these trace metals in the hepatopancreas of adult snails, Cantareus aspersus, following 14 and 28 days of exposure to low doses of dietary cadmium, up to 1 mg/kg dw (dry weight). The cadmium dose, but not the duration of exposure, had a significant effect on hepatopancreas copper deposition, the values being significantly elevated compared to controls. A significant peak in manganese levels at 14 days was found in snails administered the lowest cadmium dose. These increases occurred even in the absence of cadmium increase in the hepatopancreas. Our data suggest that low dose cadmium feeding can produce a transient disturbance in hepatopancreas copper and manganese homeostasis. Such responses may serve as early biomarkers of physiological changes occurring during the initial stages of cadmium intoxication.

Where cone snails and spiders meet: design of small cyclic sodium-channel inhibitors.

A 13 aa residue voltage-gated sodium (NaV) channel inhibitor peptide, Pn, containing 2 disulfide bridges was designed by using a chimeric approach. This approach was based on a common pharmacophore deduced from sequence and secondary structural homology of 2 NaV inhibitors: Conus kinoshitai toxin IIIA, a 14 residue cone snail peptide with 3 disulfide bonds, and Phoneutria nigriventer toxin 1, a 78 residue spider toxin with 7 disulfide bonds. As with the parent peptides, this novel NaV channel inhibitor was active on NaV1.2. Through the generation of 3 series of peptide mutants, we investigated the role of key residues and cyclization and their influence on NaV inhibition and subtype selectivity. Cyclic PnCS1, a 10 residue peptide cyclized via a disulfide bond, exhibited increased inhibitory activity toward therapeutically relevant NaV channel subtypes, including NaV1.7 and NaV1.9, while displaying remarkable serum stability. These peptides represent the first and the smallest cyclic peptide NaV modulators to date and are promising templates for the development of toxin-based therapeutic agents.-Peigneur, S., Cheneval, O., Maiti, M., Leipold, E., Heinemann, S. H., Lescrinier, E., Herdewijn, P., De Lima, M. E., Craik, D. J., Schroeder, C. I., Tytgat, J. Where cone snails and spiders meet: design of small cyclic sodium-channel inhibitors.

Effects of soil amendments on cadmium transfer along the lettuce-snail food chain: Influence of chemical speciation.

Cadmium (Cd) trophic transfer along the soil-lettuce-snail food chain was investigated using the root bags-based pot experiments. Two amendments (corn straw biochar and micro-hydroxyapatite (µHAP)) were investigated on Cd (0, 2.5, and 5 mg/kg soil) availability in soils, chemical distribution in plant cells and accumulation in snails. After 60 days, both the CaCl2 extractable Cd in rhizosphere soil (CdCaCl2,rhizo) and Cd accumulation in lettuce decreased with amendments addition. Biochar had a great capacity to reduce both Cd contents and toxicity-sensitive associated Cd (CdFi+Fii) percentages in lettuce roots at 2.5 mg/kg Cd contaminated soil; while µHAP generates a higher reduction in both Cd contents and chain transfer associated Cd (CdFi+Fii+Fiii) percentages in lettuce shoots at 5 mg/kg Cd contaminated soil. Linear regression showed that both contents of root CdFi+Fii and shoot CdFi+Fii+Fiii are better correlated with the CdCaCl2,rhizo (R2 > 0.70, p < 0.01). After 15 days feeding, almost 90% content of Cd accumulated in snail viscera. µHAP had a higher reduction in snail soft tissues Cd accumulation than biochar. Distributions of Cd in snail tissues are significantly correlated with CdFi+Fii+Fiii in shoots (viscera R2 = 0.835; soft tissue R2 = 0.771). Established quantitative relationships could be used to predict the bioavailability and transfer of Cd in terrestrial food chain in the presence of amendments.