Known as a cause of food poisoning, Bacillus cereus (B. cereus) is widespread in nature. Cereulide, the heat-stable and acid-resistant emetic toxin which is produced by some B. cereus strains, is often associated with foodborne outbreaks, and causes acute emetic toxicity at high dosage exposure. However, the toxicological effect and underlying mechanism caused by chronic low-dose cereulide exposure require to be further addressed. In the study, based on mouse model, cereulide exposure (50 μg/kg body weight) for 28 days induced intestinal inflammation, gut microbiota dysbiosis and food intake reduction. According to the cell models, low dose cereulide exposure disrupted the intestinal barrier function and caused intestinal inflammation, which were resulted from endoplasmic reticulum (ER) stress IRE1/XBP1/CHOP pathway activation to induce cell apoptosis and inflammatory cytokines production. For gut microbiota, cereulide decreased the abundances of Lactobacillus and Oscillospira. Furthermore, cereulide disordered the metabolisms of gut microbiota, which exhibited the inhibitions of butyrate and tryptophan. Interestingly, cereulide exposure also inhibited the tryptophan hydroxylase to produce the serotonin in the gut and brain, which might lead to depression-like food intake reduction. Butyrate supplementation (100 mg/kg body weight) significantly reduced intestinal inflammation and serotonin biosynthesis suppression caused by cereulide in mice. In conclusion, chronic cereulide exposure induced ER stress to cause intestinal inflammation, gut microbiota dysbiosis and serotonin biosynthesis suppression. IRE1 could be the therapeutic target and butyrate supplementation is the potential prevention strategy.

Gymnodimine A has been found in mollusks obtained along the whole northern coast of Spain from April 2017 to December 2019. This is the first time that this toxin is detected in mollusks from the Atlantic coast of Europe. The prevalence of the toxin was, in general, low, being detected on average in approximately 6% of the obtained samples (122 out of 1900). The concentrations recorded were also, in general, low, with a median of 1.3 μg kg⁻¹, and a maximum value of 23.93 μg kg⁻¹. The maxima of prevalence and concentration were not geographically coincident, taking place the first at the easternmost part of the sampled area and the second at the westernmost part. In most cases (>94%), gymnodimine A and 13-desmethyl spirolide C were concurrently detected, suggesting that Alexandrium ostenfeldii could be the responsible producer species. The existence of cases in which gymnodimine A was detected alone suggests also that a Karenia species could also be involved. The geographical heterogeneity of the distribution suggests that blooms of the producer species are mostly local. Not all bivalves are equally affected, clams being less affected than mussels, oysters, and razor clams. Due to their relatively low toxicity, and their low prevalence and concentration, it seems that these toxins do not pose an important risk for the mollusk consumers in the area.

The present study introduces a mechanically robust, sealable SPME sampler for the on-site sampling and extraction of a wide range of untargeted pollutants in environmental waters. Spray-coating and dip coating methodologies were used to coat the surfaces of six stainless steel bolts with a layer of HLB/PAN particles, which served as the extractive substrate in the proposed device. In addition, this sampler was designed to withstand rough handling, long storage times, and various environmental conditions. In order to identify whether the sampler was able to stabilize extracted compounds for long periods of time, the effects of storage time and temperature were evaluated. The results of these tests showed no significant differences in the quantity and quality of the extracted chemicals following 12 days storage at room temperature, thus confirming the device's suitability for use at sampling sites that are far away from the laboratory facilities. The proposed device was also used to perform extraction and untargeted analyses of river waters in five different geographical locations. The constituent chemicals in the samplers were analyzed and determined using high-resolution HPLC-Orbitrap MS. Toxin and Toxin-Target Database was used as a reference database for toxins and environmental contaminants. Ultimately, over 80 tentative chemicals with widely varying hydrophobicities ranging within −2.43 < logP <11.9—including drugs, metabolites, wide ranges of toxins, pesticide, and insecticides—were identified in the samplers used in the different rivers. The log P values for the tentative analytes confirmed that the introduced device is suitable for the extraction and trace analysis of wide ranges of targeted and untargeted pollutants.

The widespread cultivation of transgenic Bt cotton makes assessing the potential effects of this recombinant crop on non-target organisms a priority. However, the effect of Bt cotton on many insects is currently virtually unknown. The plant bug Adelphocoris suturalis is now a major pest of cotton in southern China and the beetle Haptoncus luteolus is one of the most ancient cotton pollinators. We conducted laboratory experiments to evaluate the toxicity of the Bt cotton varieties ZMSJ, which expresses the toxins Cry1Ac and Cry2Ab, and ZMKCKC, which expresses Cry1Ac and EPSPS, on adult A. suturalis and H. luteolus. No significant increase in the mortality of either species was detected after feeding on Bt cotton leaves or pollen for 7 days. Trace amounts of Cry1Ac and Cry2Ab proteins could be detected in both species but in vitro binding experiments found no evidence of Cry1Ac and Cry2Ab binding proteins. These results demonstrate that feeding on the leaves or pollen of these two Bt cotton varieties has no toxic effects on adult A. suturalis or H. luteolus.

Competitive ability and numerical dominance are important factors contributing to the ability of invasive ant species to establish and expand their ranges in new habitats. However, few studies have investigated the impact of environmental contamination on competitive behavior in ants as a potential factor influencing dynamics between invasive and native ant species. Here we investigated the widespread contaminant selenium to investigate its potential influence on invasion by the exotic Argentine ant, Linepithema humile, through effects on reproduction and competitive behavior. For the fecundity experiment, treatments were provided to Argentine ant colonies via to sugar water solutions containing one of three concentrations of selenium (0, 5 and 10 μg Se mL−1) that fall within the range found in soil and plants growing in contaminated areas. Competition experiments included both the Argentine ant and the native Dorymyrmex bicolor to determine the impact of selenium exposure (0 or 15 μg Se mL−1) on exploitation- and interference-competition between ant species. The results of the fecundity experiment revealed that selenium negatively impacted queen survival and brood production of Argentine ants. Viability of the developing brood was also affected in that offspring reached adulthood only in colonies that were not given selenium, whereas those in treated colonies died in their larval stages. Selenium exposure did not alter direct competitive behaviors for either species, but selenium exposure contributed to an increased bait discovery time for D. bicolor. Our results suggest that environmental toxins may not only pose problems for native ant species, but may also serve as a potential obstacle for establishment among exotic species.

In the current study, we compared protein profiles in gills of Perna viridis after exposure to Prorocentrum lima, a dinoflagellate producing DSP toxins, and identified the differential abundances of protein spots using 2D-electrophoresis. After exposure to P. lima, the level of okadaic acid (a main component of DSP toxins) in gills of P. viridis significantly increased at 6 h, but mussels were all apparently healthy without death. Among the 28 identified protein spots by MALDI TOF/TOF-MS, 12 proteins were up-regulated and 16 were down-regulated in the P. lima-exposed mussels. These identified proteins were involved in various biological activities, such as metabolism, cytoskeleton, signal transduction, response to oxidative stress and detoxification. Taken together, our results indicated that the presence of P. lima caused DSP toxins accumulation in mussel gill, and might consequently induce cytoskeletonal disorganization, oxidative stress, a dysfunction in metabolism and ubiquitination/proteasome activity.

Effects of N deficiency and salinity on root anatomy, permeability and metal (Pb, Zn and Cu) translocation and tolerance were investigated using mangrove seedlings of Rhizophora stylosa. The results showed that salt could directly reduce radial oxygen loss (ROL) by stimulation of lignification within exodermis. N deficiency, oppositely, would reduce lignification. Such an alteration in root permeability may also influence metal tolerance by plants. The data indicated that a moderate salinity could stimulate a lignified exodermis that delayed the entry of metals into the roots and thereby contributed to a higher metal tolerance, while N deficiency would aggravate metal toxicity. The results from sand pot trail further confirmed this issue. This study provides a barrier property of the exodermis in dealing with environments. The plasticity of root anatomy is likely an adaptive strategy to regulate the fluxes of gases, nutrients and toxins at root–soil interface.

Blubber samples of Indo-Pacific bottlenose (Tursiops aduncus) and spinner (Stenella longirostris) dolphins from Zanzibar, East Africa, were analyzed for a wide range of organohalogen compounds. Methoxylated polybrominated diphenyl ethers (MeO-BDEs), presumably biogenic, were found at higher concentrations than anthropogenic organochlorine pesticides (OCPs). Only traces of industrial pollutants, such as polychlorinated biphenyls, were detected. The OCP levels found off Zanzibar were lower than those reported from other regions while MeO-BDE levels were higher. The relative composition of the OCPs indicated recent use of lindane (γ-hexachlorocyclohexane) and aged residues of DDT and technical HCH. Placental transfer was estimated to 2.5% and 0.5% of the total burden of OCPs and MeO-BDEs, respectively. Overall transfer from mother to calf in Indo-Pacific bottlenose dolphins was estimated to 72% and 85% for the OCPs and MeO-BDEs burdens, respectively. Health effects of MeO-BDEs are not known, but structural similarities with well-known environmental toxins are cause for concern.

Insect gut microbiotas have a variety of physiological functions for host growth, development, and immunity. Bacillus thuringiensis (Bt) is known to kill insect pests by releasing insecticidal protoxins, which are activated in the insect midgut. However, the interplay among Bt infection, host immunity, and gut microbiota are still unclear. Here we show that Bt Cry1Ac protoxin interacts with the gut microbiota to accelerate the mortality of P. xylostella larvae. Cry1Ac protoxin was found to cause a dynamic change in the midgut and hemocoel microbiota of P. xylostella, with a significant increase in bacterial load and a significant reduction in bacterial diversity. In turn, loss of gut microbiota significantly decreased the Bt susceptibility of P. xylostella larvae. The introduction of three gut bacterial isolates Enterococcus mundtii (PxG1), Carnobacterium maltaromaticum (PxCG2), and Acinetobacter guillouiae (PxCG3) restored sensitivity to Bt Cry1Ac protoxin. We also found that Cry1Ac protoxin and native gut microbiota can trigger host midgut immune response, which involves the up-regulation of expression of Toll and IMD pathway genes and most antimicrobial peptide genes, respectively. Our findings further shed light on the interplay between insect gut microbiota and host immunity under the Bt toxin killing pressure, and this may provide insights for improving the management of Bt resistance and lead to new strategies for biological control of insect pests.

The townships of Puchuncaví and Quintero, on the coast of central Chile, have soils contaminated by atmospheric deposition of sulfur dioxide and trace elements from the nearby Ventanas Industrial Complex. The purpose of this study was to evaluate potential human health and ecological risks, by determining the spatial distribution of soil total concentrations arsenic (As), copper (Cu), lead (Pb), and zinc (Zn) in these townships. Total concentrations of these elements were determined in 245 topsoil samples, used to generate continuous distribution maps. The background concentrations of Cu, As, Pb, and Zn in the studied soils were 100, 16, 35, and 122 mg kg⁻¹, respectively. The concentrations of Cu, As, and Pb were positively correlated with each other, suggesting that their source is the Ventanas copper smelter. On the other hand, correlations for Zn were weaker than for other trace elements, suggesting low impact of the Ventanas copper smelter on spatial distribution of Zn. Indeed, only 6% of the study area exhibited Zn concentrations above the background level. In contrast, 77, 32 and 35% of the study area presented Cu, As, and Pb concentrations, respectively, above the background level. The carcinogenic risk due to exposure to As was above the threshold value of 10⁻⁰⁴ in the population of young children (1–5 years old) on 27% of the study area. These risk values are classified as unacceptable, which require specific intervention by the Chilean government. Based on the estimated concentrations of exchangeable Cu, 10, 15, and 75% of the study area exhibited high, medium, and low phytotoxicity risk, respectively.