Insect Body Defence Reactions against Bee Venom: Do Adipokinetic Hormones Play a Role?

Bees originally developed their stinging apparatus and venom against members of their own species from other hives or against predatory insects. Nevertheless, the biological and biochemical response of arthropods to bee venom is not well studied. Thus, in this study, the physiological responses of a model insect species (American cockroach, Periplaneta americana) to honeybee venom were investigated. Bee venom toxins elicited severe stress (LD₅₀ = 1.063 uL venom) resulting in a significant increase in adipokinetic hormones (AKHs) in the cockroach central nervous system and haemolymph. Venom treatment induced a large destruction of muscle cell ultrastructure, especially myofibrils and sarcomeres. Interestingly, co-application of venom with cockroach Peram-CAH-II AKH eliminated this effect. Envenomation modulated the levels of carbohydrates, lipids, and proteins in the haemolymph and the activity of digestive amylases, lipases, and proteases in the midgut. Bee venom significantly reduced vitellogenin levels in females. Dopamine and glutathione (GSH and GSSG) insignificantly increased after venom treatment. However, dopamine levels significantly increased after Peram-CAH-II application and after co-application with bee venom, while GSH and GSSG levels immediately increased after co-application. The results suggest a general reaction of the cockroach body to bee venom and at least a partial involvement of AKHs.

The effects of ammonia-N stress on immune parameters, antioxidant capacity, digestive function, and intestinal microflora of Chinese mitten crab, Eriocheir sinensis, and the protective effect of dietary supplement of melatonin

Ammonia nitrogen pollution seriously affects the economic benefits of Chinese mitten crab (Eriocheir sinensis) farming. In this study, we first evaluated the protective effects of melatonin (MT) on immune parameters, antioxidant capacity, and digestive enzymes of E. sinensis under acute ammonia nitrogen stress. The results showed that ammonia-N stress significantly decreased the antibacterial ability of crabs, nevertheless MT could significantly improve it under ammonia-N stress (P < 0.05). Ammonia-N group hemolymph antioxidant capacity indicators (T-AOC, T-SOD, GSH-Px) were significantly decreased than control (p < 0.05), while the MT ammonia-N group hemolymph T-SOD activity significantly increased than ammonia-N group (p < 0.05). For hepatopancreas, ammonia-N group GSH-PX activity significantly decreased than control group, but MT ammonia-N group was significant increased than ammonia-N (p < 0.05). Ammonia-N stress has significantly increased the content of MDA in hemolymph and hepatopancreas (p < 0.05), but MT ammonia-N treatment significantly decreased than ammonia-N group (p < 0.05). Compared with the control group, ammonia-N significantly reduced the activities of Trypsin in the intestine and hepatopancreas (p < 0.05), while MT ammonia-N group can significantly improve the intestinal trypsin activity than ammonia-N (p < 0.05). The intestinal microbiota of E. sinensis results showed that ammonia-N stress significantly decreased the relative abundance of Bacteroidetes (p < 0.05). Ammonia-N stress significantly decreased the Dysgonomonas and Rubellimicrobium, and the Citrobacter significantly increased. In summary, melatonin has a protective effect on E. sinensis under ammonia-N stress. Acute ammonia-N stress may lead to the decrease of probiotics and the increase of pathogenic bacteria, which may be closely related to the impairment of digestive function and immune function.

Solanum nigrum Extract and Solasonine Affected Hemolymph Metabolites and Ultrastructure of the Fat Body and the Midgut in Galleria mellonella

Glycoalkaloids, secondary metabolites abundant in plants belonging to the Solanaceae family, may affect the physiology of insect pests. This paper presents original results dealing with the influence of a crude extract obtained from Solanum nigrum unripe berries and its main constituent, solasonine, on the physiology of Galleria mellonella (Lepidoptera) that can be used as an alternative bioinsecticide. G. mellonella IV instar larvae were treated with S. nigrum extract and solasonine at different concentrations. The effects of extract and solasonine were evaluated analyzing changes in carbohydrate and amino acid composition in hemolymph by RP-HPLC and in the ultrastructure of the fat body cells by TEM. Both extract and solasonine changed the level of hemolymph metabolites and the ultrastructure of the fat body and the midgut cells. In particular, the extract increased the erythritol level in the hemolymph compared to control, enlarged the intracellular space in fat body cells, and decreased cytoplasm and lipid droplets electron density. The solasonine, tested with three concentrations, caused the decrease of cytoplasm electron density in both fat body and midgut cells. Obtained results highlighted the disturbance of the midgut and the fat body due to glycoalkaloids and the potential role of hemolymph ingredients in its detoxification. These findings suggest a possible application of glycoalkaloids as a natural insecticide in the pest control of G. mellonella larvae.

Cucurbitacin B Suppresses Hyperglycemia Associated with a High Sugar Diet and Promotes Sleep in Drosophila melanogaster

Secondary metabolites enable plants to protect themselves from herbivorous insects. Among these, cucurbitacin B (cuc-B) is a bitter-tasting compound with promising pharmacological potential. Dietary exposure to cuc-B lowered the hemolymph glucose levels of Drosophila melanogaster fed with a high carbohydrate diet, which is homologous to high blood glucose in humans, and its effect was comparable to that of metformin, a well-known glucose-lowering drug. Furthermore, cuc-B reduced tissue sugar levels and glycogen levels, as well as triacylglycerol levels. Our results thus highlight the potential applicability of this compound to treat chronic metabolic diseases such as diabetes and obesity. Additionally, we analyzed sleep quality and taste-associative memory enhancement after cuc-B and metformin treatment. Both supplements increased nighttime bout length and metformin increased memory consolidation. Therefore, discarded shell of Cucurbitaceae could be processed into health supplements.

Development of a three-compartment toxicokinetic model for T-2 toxin in shrimp by blindfold particle swarm optimization algorithm

Tricothecenes-2 toxin (T-2) is a major mycotoxin that is widely distributed in aquatic feeds and poses a huge challenge to the aquatic industry, but there is scant information on the toxicokinetics of T-2 in aquatic animals. Here, we describe the development of a three-compartment toxicokinetic model for the absorption, distribution, metabolism and elimination (ADME) of T-2 in shrimp. The three compartments were central (the hemolymph), slow metabolizing and fast metabolizing compartments to account for the varying ADME rates of T-2 in different shrimp organs. The toxicokinetic model was solved by the blindfold particle swarm optimization algorithm, and the values for the model equation parameters were obtained by applying the experimental data of T-2 concentrations in shrimp. The model had a good fit with the experimental data. It was revealed through the model that after i.m. administration, T-2 was rapidly absorbed into the hemolymph and distributed into shrimp organs. The hepatopancreas and intestine belonged to the fast and muscle to the slow metabolizing compartments, respectively, while the hemolymph had no capacity to metabolize T-2. The T-2 elimination rates in the hepatopancreas and intestine were similar and quite high while that in the muscle was very low. The methods used in developing and solving the model could be used for similar toxicokinetic and pharmacokinetic studies of other animals.

Immune toxicity of phenanthrene and its combined effects of white spot syndrome virus on the survival of kuruma shrimp (Penaeus Japonicus)

Shrimp inhabiting coasts that are frequented by humans are exposed to various pollutants. Additionally, viral infections that cause serious damage to shrimp populations have been observed in these environments. The present study sought to evaluate the immunotoxic effects of phenanthrene (Phe), a pollutant detected in coastal environments, on kuruma shrimp (Penaeus japonicus). We further examined the survival of shrimp following combined exposure to Phe (30 or 300 μg/L) and white spot syndrome virus (WSSV). Results show that exposure to Phe for seven days decreased immune system-related parameters, including total hemocyte count and phenoloxidase activity in hemolymph (p < 0.05). However, these effects were not detected after three days of exposure. Moreover, a combined exposure assay revealed that shrimp mortality increased following exposure to 300 μg/L Phe and infection with WSSV. The number of WSSV gene copies was also observed to increase in these co-exposed shrimp. Taken together, these results indicate that long-term Phe exposure impairs the immune system of P. japonicus, resulting in fatal proliferation of WSSV. Hence, considering that combined exposure to Phe and WSSV leads to increased mortality of shrimp, it is imperative that the detrimental effects elicited by multiple stresses be considered, and controlled, in areas inhabited by kuruma shrimp.

The effect of chronic exposure to chloridazon and its degradation product chloridazon-desphenyl on signal crayfish Pacifastacus leniusculus

The effects of chloridazon (Ch) and its metabolite chloridazon-desphenyl (Ch-D) at the environmentally relevant concentrations of 0.45 µg/L and 2.7 µg/L on signal crayfish Pacifastacus leniusculus were assessed in a 30-day exposure followed by a 15-day depuration period. Locomotion, biochemical haemolymph profile, oxidative and antioxidant parameters, and histopathology were evaluated. Crayfish exposed to Ch at 0.45 µg/L and 2.7 µg/L showed significantly (p < 0.01) higher CAT activity and GSH level in hepatopancreas and gill compared to controls. The concentration of Ch at 2.7 µg/L was associated with significantly (p < 0.01) higher levels of GLU, LACT, ALT, AST in haemolymph compared to controls. Chloridazon-desphenyl exposure at both tested concentrations caused significantly higher (p < 0.01) GLU, LACT, ALT, AST, NH₃, and Ca in haemolymph; lipid peroxidation (TBARS) levels in hepatopancreas; and CAT activity and GSH level in hepatopancreas and gill. Alterations of structure including focal dilatation of tubules, increased number of fibrillar cells, and haemocyte infiltration in the interstitium were observed with 2.7 µg/L Ch and with both Ch-D exposures. Locomotion patterns did not vary significantly among groups. A 15-day recovery period was insufficient to restore normal physiological parameters in exposed groups. Chloridazon and its metabolite Ch-D exerts harmful effects on crayfish.

Impacts of microplastic fibres on the marine mussel, Mytilus galloprovinciallis

Tumble dryer lint has been employed as a surrogate for synthetic and processed (microplastic) fibres discharged to the environment from laundering activities and exposed to marine mussels (Mytilus galloprovinciallis) in controlled experiments for a period of 7 d. A range of biological responses at different levels of organisation were subsequently determined, with copper employed concurrently as a positive control. Physiological changes were assessed from measurements of clearance rate, histopathological effects were evaluated from abnormalities in (or injuries to) gill and digestive gland tissues, and genetic damage was determined by measuring DNA strand breaks using the comet assay. With increasing lint concentration (over the range 56-180 mg L^-1) we observed a reduction in mean clearance rate, increasing extents of abnormality in both gills (e.g. deciliation and hypertrophy) and digestive gland (e.g. atrophy and necrosis), and an increase in damage to DNA. The precise causes of these effects are unclear but likely arise from both the fibrous material itself and from chemicals (e.g. additives and metals) that are mobilised from the polymers into seawater or the digestive tract. The latter assertion is consistent with an observed increase in the release of certain trace elements (e.g. zinc) into the exposure medium with increasing lint concentration. Although microfibre concentrations we employed are significantly greater than those typically encountered in the environment, the results indicate the potential for this type of material to exert a range of adverse effects on exposed marine animals.

The effect of the insecticide diazinon on the osmoregulation and the avoidance response of the white leg shrimp (Penaeus vannamei) is salinity dependent

Diazinon is one of the insecticides that represent a high risk for Costa Rican estuarine environments due to its widespread use in pineapple plantations. In estuaries, organisms are frequently submitted to stress caused by natural factors (e.g., continuous changes in salinity levels) and, additionally, to stress due to contamination. Therefore, the driving question of this study was: will organisms be more susceptible to suffer the deleterious effects caused by diazinon because of the stress resulting from the salinity changes? The estuarine shrimp Penaeus vannamei was used as the model organism and two responses were measured: osmoregulation (the physiological effect after a forced and continuous 24 h-exposure) and avoidance [the behavioural effect after a short (3 h) non-forced, multi-compartmented exposure]. Juveniles were exposed to diazinon (0.1, 1, 10 and 100 μg/L) at three different salinities (10, 20 and 30). Disruption in the capacity to regulate the haemolymph osmotic pressure was observed at a salinity of 30 in individuals exposed to diazinon and methanol (used as vehicle). At that salinity, the ability of shrimps to detect and avoid the highest diazinon concentrations was impaired. P. vannamei juveniles inhabit environments with a high variation in salinity, but with an optimum osmotic point close to a salinity of 20; therefore, the higher the salinity, the greater the vulnerability of shrimps to the effects of diazinon. From an ecological point of view, this combined effect of salinity and contamination might also limit the spatial distribution of the organisms.

Physiological changes in the hemolymph of juvenile shrimp Litopenaeus vannamei to sublethal nitrite and nitrate stress in low-salinity waters

Juveniles of the shrimp Litopenaeus vannamei (3.3 ± 0.4 g) were exposed separately to nitrite (0.0, 1.1, 2.6, and 5.3 mg/L nitrogen as nitrite [NO₂^--N]) and nitrate (0, 90, 225 and 400 mg/L nitrogen as nitrate [NO₃^--N]) concentrations equivalent to 0, 10, 25, and 50% of the LC₅₀-96 h value of NO₂^--N and NO₃^--N in low salinity water (3 g/L). Shrimps responded to nitrite and nitrate according to changes in oxyhemocyanin, glucose, lactate and ion levels in the hemolymph after 6, 12, 24, and 48 h of exposure. Oxyhemocyanin levels decreased with increasing nitrite and nitrate levels and were higher at 50% exposure to the contaminants. Compared to the control, glucose and lactate increased significantly at 50% exposure to nitrite and nitrate, particularly at 12 and 24 h. Na⁺ in the hemolymph changed with nitrite and nitrate, while K⁺ only changed ˜with nitrite.

Acute effects of neonicotinoid insecticides on Mytilus galloprovincialis: A case study with the active compound thiacloprid and the commercial formulation calypso 480 SC

Pesticides can enter aquatic environments potentially affecting non-target organisms. Unfortunately, the effects of such substances are still poorly understood. This study investigated the effects of the active neonicotinoid substance thiacloprid (TH) and the commercial product Calypso 480 SC (CA) (active compound 40.4% TH) on Mytilus galloprovincialis after short-term exposure to sublethal concentrations. Mussels were tested for seven days to 0, 1, 5 and 10 mg L^-1 TH and 0, 10, 50 and 100 mg L^-1 CA. For this purpose, several parameters, such as cell viability of haemocytes and digestive cells, biochemical haemolymph features, superoxide dismutase (SOD) and catalase (CAT) enzymatic activity of gills and digestive gland, as well as histology of such tissues were analysed. The sublethal concentrations of both substances lead to abatement or completely stopping the byssal fibres creation. Biochemical analysis of haemolymph showed significant changes (P < 0.01) in electrolytes ions (Cl^-, K⁺, Na⁺, Ca²⁺, S-phosphor), lactate dehydrogenase (LDH) enzyme activity and glucose concentration following exposure to both substances. The TH-exposed mussels showed significant imbalance (P < 0.05) in CAT activity in digestive gland and gills. CA caused significant decrease (P < 0.05) in SOD activity in gills and in CAT activity in both tissues. Results of histological analyses showed severe damage in both digestive gland and gills in a time- and concentration-dependent manner. This study provides useful information about the acute toxicity of a neonicotinoid compound and a commercial insecticide on mussels. Nevertheless, considering that neonicotinoids are still widely used and that mussels are very important species for marine environment and human consumption, further researches are needed to better comprehend the potential risk posed by such compounds to aquatic non-target species.

Nitric oxide effects on Rhodnius prolixus's immune responses, gut microbiota and Trypanosoma cruzi development

The immune system of Rhodnius prolixus comprehends the synthesis of different effectors that modulate the intestinal microbiota population and the life cycle of the parasite Trypanosoma cruzi inside the vector midgut. One of these immune responses is the production of reactive nitrogen species (RNS) derived by the action of nitric oxide synthase (NOS). Therefore, we investigated the effects of L-arginine, the substrate for nitric oxide (NO) production and N_ω-Nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of NOS, added in the insect blood meal. We analyzed the impact of these treatments on the immune responses and development of intestinal bacteria and parasites on R. prolixus nymphs. The L-arginine treatment in R. prolixus nymphs induced a higher NOS gene expression in the fat body and increased NO production, but reduced catalase and antimicrobial activities in the midgut. As expected, L-NAME treatment reduced NOS gene expression in the fat body. In addition, L-NAME treatment diminished catalase activity in the hemolymph and posterior midgut reduced phenoloxidase activity in the anterior midgut and increased the antimicrobial activity in the hemolymph. Both treatments caused a reduction in the cultivatable intestinal microbiota, especially in insects treated with L-NAME. However, T. cruzi development in the insect's digestive tract was suppressed after L-arginine treatment and the opposite was observed with L-NAME, which resulted in higher parasite counts. Therefore, we conclude that induction and inhibition of NOS and NO production are associated with other R. prolixus humoral immune responses, such as catalase, phenoloxidase, and antibacterial activities in different insect organs. These alterations reflect on intestinal microbiota and T. cruzi development.

Exposure of bay scallop Argopecten irradians to micro-polystyrene: Bioaccumulation and toxicity

Marine microplastic pollution poses a threat to aquatic organisms, including bivalves. In this study, we investigated the accumulation of microplastics and their elicited antioxidant stress response in the bay scallop Argopecten irradians. Scallops were exposed to 1 μm diameter micro-polystyrene (MP) beads at 10, 100, and 1000 beads/mL concentrations for a 7 day period. Bead presence in the digestive diverticula and defense responses in the digestive diverticula and hemolymph were measured at 1, 3, 5, and 7 days. The activity and expression of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) and H₂O₂ in the digestive diverticula and/or hemolymph of scallops increased with microplastic concentration and exposure duration. These results suggest that microplastics can accumulate in the digestive diverticula of A. irradians, and that exposure to microplastics induces oxidative stress in bivalves. It is likely that exposure to high concentrations of micro- or nano-sized plastic particles could potentially have adverse effects in bivalves.

Systemic muscle wasting and coordinated tumour response drive tumourigenesis

Cancer cells demand excess nutrients to support their proliferation, but how tumours exploit extracellular amino acids during systemic metabolic perturbations remain incompletely understood. Here, we use a Drosophila model of high-sugar diet (HSD)-enhanced tumourigenesis to uncover a systemic host-tumour metabolic circuit that supports tumour growth. We demonstrate coordinate induction of systemic muscle wasting with tumour-autonomous Yorkie-mediated SLC36-family amino acid transporter expression as a proline-scavenging programme to drive tumourigenesis. We identify Indole-3-propionic acid as an optimal amino acid derivative to rationally target the proline-dependency of tumour growth. Insights from this whole-animal Drosophila model provide a powerful approach towards the identification and therapeutic exploitation of the amino acid vulnerabilities of tumourigenesis in the context of a perturbed systemic metabolic network.

Transcriptome analysis reveals the potential mechanism of dietary carotenoids improving antioxidative capability and immunity of juvenile Chinese mitten crabs Eriocheir sinensis

Carotenoids are known to be involved in the regulation of the antioxidative capability, immune response and stress resistance in crustacean species; however, very limited information is available on their underlying molecular mechanisms. This study performed transcriptome sequencing of hemolymph and hepatopancreas of juvenile Chinese mitten crabs (Eriocheir sinensis) that fed with three diets, i.e. diet A containing 90 mg kg^-1 dry weight of astaxanthin, diet B containing 200 mg kg^-1 dry weight of β-carotene and control diet without supplementation of dietary carotenoids. The results showed that there were 2955 and 497 differentially expressed genes (DEGs) in the hemolymph between the astaxanthin treatment and control groups, and between the β-carotene treatment and control groups, respectively. Moreover, compared with the control group, 833 and 1886 DEGs were obtained in the hepatopancreas of the astaxanthin treatment and the β-carotene treatment groups, respectively. The DEGs in the three groups were enriched in 255 specific KEGG metabolic pathways according to KEGG enrichment analysis. Through this study, a series of key genes involved in Nrf2 signalling, ROS production, intracellular antioxidant enzymes and chaperones were significantly affected by dietary carotenoids. Dietary carotenoids also significantly altered the expression levels of immune-related molecules associated with signal transduction, prophenoloxidase cascade, apoptosis, pattern recognition proteins/receptors and antimicrobial peptides. In conclusion, this transcriptomic study provides valuable information for understanding the molecular mechanism and potential pathway of dietary carotenoids improved the antioxidative capability and immunity of juvenile E. sinensis.

The Modulation of Trehalose Metabolism by 20-Hydroxyecdysone in Antheraea pernyi (Lepidoptera: Saturniidae) During its Diapause Termination and Post-Termination Period

Trehalose plays a crucial role in the diapause process of many insects, serving as an energy source and a stress protectant. Trehalose accumulation has been reported in diapause pupae of Antheraea pernyi; however, trehalose metabolic regulatory mechanisms associated with diapause termination remain unclear. Here, we showed that the enhanced trehalose catabolism was associated with an increase in endogenous 20-hydroxyecdysone (20E) in hemolymph of A. pernyi pupae during their diapause termination and posttermination period. Injection of 20E increased the mRNA level of trehalase 1A (ApTre-1A) and trehalase 2 (ApTre-2) of A. pernyi diapause pupae in a dose-dependent manner but did not affect the mRNA level of trehalase 1B (ApTre-1B). Meanwhile, exogenous 20E increased the enzyme activities of soluble and membrane-bound trehalase, leading to a decline in hemolymph trehalose. Conversely, the expression of ApTre-1A and ApTre-2 were down-regulated after the ecdysone receptor gene (ApEcRB1) was silenced by RNA interference or by injection of an ecdysone receptor antagonist cucurbitacin B (CucB), which inhibits the 20E pathway. Moreover, CucB treatment delayed adult emergence, which suggests that ApEcRB1 might be involved in regulating pupal-adult development of A. pernyi by mediating ApTre-1A and ApTre-2 expressions. This study provides an overview of the changes in the expression and activity of different trehalase enzymes in A. pernyi in response to 20E, confirming the important role of 20E in controlling trehalose catabolism during A. pernyi diapause termination and posttermination period.

A comparative study of enzymatic and immunological parameters in Planorbarius corneus and Biomphalaria glabrata exposed to the organophosphate chlorpyrifos

This study aimed to investigate the acute effects of chlorpyrifos on biomarkers related to neurotoxicity and immunotoxicity in two allopatric freshwater gastropod species belonging to the family Planorbidae. For this purpose, Planorbarius corneus and Biomphalaria glabrata were exposed to chlorpyrifos (active ingredient or commercial formulation) for 48 h at environmentally realistic concentrations (1 and 7.5 μg L^-1). Basal acetylcholinesterase activity in soft tissues and hemolymph was almost one order of magnitude higher in P. corneus than in B. glabrata. However, upon chlorpyrifos exposure, statistically significant inhibition of enzymatic activity was registered in both species. Acetylcholinesterase was more sensitive to inhibition in soft tissues than in hemolymph. The highest inhibition was observed in the B. glabrata soft tissues exposed to the commercial formulation (88 % at 1 μg L^-1 and 93 % at 7.5 μg L^-1). Hemocyte number and lysosomal membrane stability did not show significant changes with respect to controls in any of the exposed groups. Superoxide anion generation was diminished (21-46 %) in P. corneus hemocytes exposed to the active ingredient and in B. glabrata hemocytes exposed to the active ingredient or the formulation. In contrast, hemocyte phagocytic activity increased in all exposed groups. Phagocytosis was most stimulated (89 %) in hemocytes sampled from B. glabrata treated with 7.5 μg L^-1 chlorpyrifos. Altogether the results suggest that the freshwater gastropods P. corneus and B. glabrata are suitable model animals for environmental monitoring studies in the Northern Hemisphere and Latin America, respectively. Furthermore, these results add information on the relevance of testing pesticide formulations and on the usefulness of acetylcholinesterase inhibition and immunological parameters as biomarkers of the acute effects of chlorpyrifos in these species.

Effects of exposure to waterborne polystyrene microspheres on lipid metabolism in the hepatopancreas of juvenile redclaw crayfish, Cherax quadricarinatus

Previous research has identified microplastics as new environmental pollutants that are widely distributed in a variety of environments, including aquaculture environments. However, the potential hazard of microplastics to aquaculture animals, especially toward lipid metabolism involved with the survival and growth of aquatic animal, has not yet been investigated. In the present study, redclaw crayfish (Cherax quadricarinatus) were exposed to different concentrations of 200 nm-sized polystyrene microspheres (0, 0.5, and 5 mg/L) for 21 days, to investigate the effects of microplastics on lipid metabolism. After ingestion, the microplastics were distributed in the intestines and hepatopancreas, and appeared to inhibit the growth of Cherax quadricarinatus. Subsequently, the lipid levels in the hepatopancreas and hemolymph was detected, and found that after 21 days of exposure, the lipid content and free fatty acids in the hepatopancreas and hemolymph decreased significantly, and total cholesterol and triglycerides levels increased significantly in the hemolymph. This might have been caused by insufficient intake of exogenous fat. A significant decrease in lipase activity also supported this view. The activity of lipoprotein lipase related to lipolysis in the hepatopancreas increased significantly, while the activity of fatty acid synthase related to fat synthesis increased, and the activity of acetyl-CoA carboxylase decreased. These results indicated disturbed lipid metabolism in the hepatopancreas. The significant increase of lipid transport-related low-density lipoprotein indicated that the lipolytic capacity was higher than the lipid synthesis capacity. The expression levels of fatty acid metabolism-related genes FAD6 and FABP decreased significantly, indicating that the fatty acid utilization ability of hepatopancreas cells was inhibited, which was consistent with the results of enzyme activities. Thus, microplastics represent a potential hazard to redclaw crayfish, at least on lipid metabolism. This study provided basic data on the ecotoxicological effects of microplastics on crustaceans.

Toxic effect of chronic waterborne copper exposure on growth, immunity, anti-oxidative capacity and gut microbiota of Pacific white shrimp Litopenaeus vannamei

Copper can be accumulated in water through excessive sewage discharge or residual algaecide to generate toxic effect to aquatic animals. In this study, the juvenile of Pacific white shrimp, Litopenaeus vannamei was exposed to 0 (control), 0.05, 0.1, 0.2, 0.5 or 1 mg Cu²⁺ L^-1 for 30 days. Growth, immune function, anti-oxidative status and gut microbiota were evaluated. Weight gain and specific growth rate of L. vannamei were significantly decreased with the increase of ambient Cu²⁺. Enlarged lumen and ruptured cells were found in the hepatopancreas of shrimp in the 0.5 or 1 mg Cu²⁺ L^-1 treatment. Total hemocyte counts of shrimp in 0.5 or 1 mg Cu²⁺ L^-1 were significantly lower than in the control. The hemocyanin concentration was also significantly increased in 0.2 or 0.5 mg Cu²⁺ L^-1. Lysozyme contents were reduced in shrimp when Cu²⁺ exceeded 0.2 mg L^-1. Meanwhile, activities of superoxide dismutase and glutathione peroxidase were increased in the hepatopancreas and the activity of Na⁺-K⁺ ATPase was decreased in the gills with increasing Cu²⁺. The mRNA expressions of immune deficiency, toll-like receptor and caspase-3 were all significantly higher in the hepatopancreas in 0.05 mg Cu²⁺ L^-1 than in the control. For the diversity of intestinal microbes, Bacteroidetes significantly decreased in 1 mg Cu²⁺ L^-1 at the phylum level. KEGG pathway analysis demonstrates that 1 mg L^-1 Cu²⁺ can significantly alter metabolism, cellular processes and environmental information processing. This study indicates that the concentration of 1 mg L^-1 Cu can negatively impact growth, hemolymph immunity, anti-oxidative capacity and gut microbiota composition of L. vannamei.

A new protocol for the simultaneous flow cytometric analysis of cytotoxicity and immunotoxicity on zebra mussel (Dreissena polymorpha) hemocytes

Immunotoxicity analysis receives a strong interest in environmental a priori and a posteriori risk assessment procedures considering the direct involvement of the immune system in the health status of organisms, populations and thus ecosystems. The freshwater mussel Dreissena polymorpha is an invasive species widely used in ecotoxicology studies and biomonitoring surveys to evaluate the impacts of contaminants on aquatic fauna. Bivalve hemocytes are the immunocompetent cells circulating in the open circulatory system of the organism. However, there is nowadays no consensus on a protocol to evaluate the immunocompetent state of this particular cell type using flow cytometry. Wild species such as D. polymorpha present several technical barriers complicating their analyze including (i) the quality and the purity of the hemolymph sample, (ii) the controversial characterization of hemocyte subpopulations and their diversity, (iii) the quantity of biological material, and (iv) the high inter-individual variability of hemocyte responses. The present work proposes several technical and analytical improvements to control the above-mentioned issues. The inclusion of sedimentation and cell detachment steps in the pre-analytical phase of the protocol substantially ameliorate the quality of the hemolymph sample as well as the accuracy of the cytometric measurements, by selecting the analyzed cells on their adhesion ability and by increasing the concentration of the analyzed events. The development of an effective triple-labeling procedure including the cellular probe Hoechst® 33342, the membrane impermeant dye propidium iodide and yellow-green fluorescent microspheres allowed the simultaneous analysis of cytotoxicity and phagocytosis activity in hemocytes. It also significantly enhanced the accuracy of hemocyte endpoint measurements by eliminating non-target events from the analysis and allowing relevant gating strategies. Finally, the use of pooled samples of hemolymph noticeably reduced inter-sample variability while providing more plasticity in the experimental design and improving the discriminating potency between treatments. The developed protocol is suitable for ex vivo exposure of hemocyte in a chemical/environmental toxicity assessment as well as for in vivo exposure in the laboratory or in situ biomonitoring surveys with few adaptations.

Acute and long-term manganese exposure and subsequent accumulation in relation to idiopathic blindness in the American lobster, Homarus americanus

Manganese (Mn) is a hypoxic reactive metal commonly found in marine sediments. Under hypoxic conditions the metal becomes fully reduced to Mn²⁺ and is biologically available to the benthic community for uptake. Mn is also a potent neurotoxin and it may play a role in the etiology of idiopathic blindness that has been observed in American lobsters. An acute exposure study was designed to expose American lobster, Homarus americanus, to 0, 20, 80, 150, and 300 mg L^-1 (ppm) for 96 hs to explore disparities in Mn accumulation among several tissues: optic nerve, brain, hepatopancreas, muscle, hemolymph, gill, and exoskeleton. These concentrations were based on realistic pore-water concentrations (20 mg L^-1), high sediment concentrations (80 mg L^-1), and unrealistically high concentrations to determine lethality (150 and 300 mg L^-1). A positive correlation between Mn accumulation and exposure concentration was observed in all tissues examined. In the internal tissues, manganese concentrations showed a high affinity towards brain, optic nerve, and hemolymph. In the exoskeleton and gills, Mn concentrations were also high, possibly because of internal uptake as well as external adsorption. Concentrations of Mn in tissues from the acute exposure study followed the accumulation pattern: hemolymph > gill > exoskeleton > optic nerve > brain > hepatopancreas = muscle. A long-term exposure study lasting seven weeks was designed to investigate the potential link between high Mn exposure and idiopathic blindness, a condition that affects an estimated 50 % of the adult American lobster population off Southern New England (SNE), USA. A comparison of these exposure studies showed evidence of time-dependent Mn accumulation in brain, muscle, exoskeleton, and gill tissue. Although the relationship between Mn exposure and blindness was not apparent, there was a modest trend in the development of blindness (Chi-square, p = 0.102) in animals exposed to a high concentration (150 mg L^-1) of the metal. With no mortalities occurring in the acute study and only one mortality in the long-term study, it is highly unlikely that Mn is acutely toxic to American lobsters at environmentally relevant concentrations. Its potential role in idiopathic blindness remains to be determined.

Immunological response of white shrimp (Litopenaeus vannamei) to sublethal concentrations of malathion and endosulfan, and their mixture

Cellular and humoral responses were evaluated in Litopenaeus vannamei juveniles when exposed to malathion, endosulfan, and their mixture. Each experiment was performed in the hemolymph collected at each exposure time (5 and 96 h) in duplicate; total hemocyte count, coagulation time, hemocyanin concentration, phenoloxidase (PO) and superoxide dismutase (SOD) activities were quantified. Survival was not affected by pesticides applied individually and mixed. Clotting time did not show significant differences concerning increase of concentration percentage of the pesticides tested. In organisms exposed to the pesticide mixture, hemocyanin decreased at 5 h of exposure as the concentration increased. Only in the malathion experiment did exposed shrimp to 10 and 50% of the LC₅₀-96 h show significantly (p < 0.05) higher hemocyte contents. For malathion, significantly (p < 0.05) lower PO values in shrimp exposed to higher concentrations (10 and 50% of the LC₅₀-96 h) were determined. While for the mixture treatment, high SOD value was determined at high exposure time and concentration. Malathion was the pesticide that showed an effect on some variables even at sublethal concentrations. The Continuous Concentration Criteria of the United States Environmental Protection Agency did not represent effects on the variables when they were compared with the averages of the control group.

Wastewater bioremediation by mangrove ecosystems impacts crab ecophysiology: In-situ caging experiment

Mangroves are tidal wetlands that are often under strong anthropogenic pressures, despite the numerous ecosystem services they provide. Pollution from urban runoffs is one such threats, yet some mangroves are used as a bioremediation tool for wastewater (WW) treatment. This practice can impact mangrove crabs, which are key engineer species of the ecosystem. Using an experimental area with controlled WW releases, this study aimed to determine from an ecological and ecotoxicological perspective, the effects of WW on the red mangrove crab Neosarmatium africanum. Burrow density and salinity levels (used as a proxy of WW dispersion) were recorded, and a 3-week caging experiment was performed. Hemolymph osmolality, gill Na⁺/K⁺-ATPase (NKA) activity and gill redox balance were assessed in anterior and posterior gills of N. africanum. Burrow density decreased according to salinity decreases around the discharged area. Crabs from the impacted area had a lower osmoregulatory capacity despite gill NKA activity remaining undisturbed. The decrease of the superoxide dismutase activity indicates changes in redox metabolism. However, both catalase activity and oxidative damage remained unchanged in both areas but were higher in posterior gills. These results indicate that WW release may induce osmoregulatory and redox imbalances, potentially explaining the decrease in crab density. Based on these results we conclude that WW release should be carefully monitored as crabs are key players involved in the bioremediation process.

Responses of hemocyanin and energy metabolism to acute nitrite stress in juveniles of the shrimp Litopenaeus vannamei

Nitrite is a common toxic substance in culture systems of Litopenaeus vannamei, and the stress may disturb hemocyanin synthesis and energy metabolism and result in shrimp death. In the present study, nitrite at concentrations of 0 (control), 3.3 (46.2 NO₂-N mg/L), 6.6 (92.4) and 9.9 mM (138.6) was used to evaluate the responses of hemocyanin level and energy metabolism in L. vannamei (5.80 ± 0.44 cm, 1.88 ± 0.38 g) for 96 h. The mortality rate at 96 h increased with nitrite concentration (50% at 9.9 mM, 40% at 6.6 mM, 30% at 3.3 mM, and 10% at 0 mM). In general, HIF-1α and hemocyanin mRNA expression in the nitrite stress groups was upregulated from 6 to 12 h and downregulated from 24 to 96 h. In the hemolymph, nitrite levels were significantly elevated in a dose-dependent manner, and exposure to nitrite stress significantly decreased the oxyhemocyanin content from 24 to 96 h. The glucose and lactate levels in the hemolymph in the nitrite stress groups were higher than those in the control group from 12 to 96 h. Compared with the control group, the shrimp in the nitrite stress groups exhibited decreased glycogen concentrations in the hepatopancreas. The triglyceride (TG) levels in the nitrite stress groups were all higher than those in the control group from 48 to 96 h. The hexokinase (HK) activity in the hepatopancreas and muscle increased in the nitrite stress groups from 48 to 96 h. In general, nitrite stress enhanced the activities of pyruvate kinase (PK), phosphofructokinase (PFK) and lactate dehydrogenase (LDH) in muscle from 24 to 96 h. In addition, nitrite stress decreased the activities of succinate dehydrogenase (SDH) and fatty acid synthase (FAS) from 24 to 96 h in the hepatopancreas and muscle. This study indicates that exposure to nitrite stress can enhance the accumulation of nitrite in the hemolymph and then reduce oxygenation and hemocyanin synthesis, leading to tissue hypoxia and thereby resulting in accelerated anaerobic metabolism and the inhibition of aerobic metabolism. The effects of nitrite stress on hemocyanin synthesis and energy metabolism may be one of the reasons for the mortality of L. vannamei in culture systems.

Single and Combined Effects of Zinc and Manganese on the Bivalve Anodontites trapesialis: Complementary Endpoints to Support the Hypothesis of Manganese Promoting Metabolic Suppression in Gills

Manganese (Mn) might stimulate the valve closure reflex in the freshwater bivalve Anodontites trapesialis, leading to metabolic suppression, whereas zinc (Zn) is not able to modify this behavior. To investigate this particular response, we exposed A. trapesialis specimens to Mn (0.5 mg L^-1 ) and Zn (1.0 mg L^-1 ) alone, and to their mixture, to measure further endpoints in different clam tissues: glycogen level in gills, and calcium (Ca²⁺ ), sodium (Na⁺ ), and chloride (Cl^- ) concentrations in the hemolymph. Furthermore, we used cutting-edge technology, proteomics, to evaluate modifications in protein patterns under the 3 exposure tests. The main results highlighted that only Mn caused a clear drop in glycogen levels in gills, an increase in Ca²⁺ and Na⁺ , and a simultaneous decrease in Cl^- concentration in the hemolymph. The proteomic analysis confirmed that Mn promoted more effects in A. trapesialis than the other tested conditions, because the number of proteins modulated was higher than the results obtained after exposure to Zn and the mixture. Moreover, 11 of the 12 modulated proteins were down-expressed. These results consolidate the hypothesis that Mn might suppress gill metabolic rate in A. trapesialis. Environ Toxicol Chem 2019;38:2480-2485. © 2019 SETAC.

Effects of BDE-47 exposure on immune-related parameters of Mytilus galloprovincialis

The persistent pollutants polybrominated diphenyl ethers (PBDEs) have been demonstrated to produce several negative effects on marine organisms. Although Mytilus galloprovincialis was extensively studied as model system, the effects of PBDEs on the innate immune system of mussels remains unclear. In this study, except for the control treatment, specimens of M. galloprovincialis were fed with microalgae treated with increasing concentrations of PBDEs (maximum level 100 ng L^-1 of BDE-47 per day). BDE-47 treatment was maintained for 15 days and then the animals were fed with the same control diet, without contaminants, for 15 days. Samples of haemolymph (HL) were obtained at T0, T15 and T30 days of the experiment to evaluate different parameters related to immunity, such as neutral red retention time, and peroxidase, protease, antiprotease, lysozyme and bactericidal activities. BDE-47 exposure for 15 days affected both the stability of haemocytes and humoral parameters. In addition, the obtained results indicated that, at 30 days, after 15 days of culture without contaminant, the immune parameters were still affected, as some of them did not return to the basal levels, and others remained stimulated. Overall the results indicate that BDE-47 exposures at environmentally realistic levels may affect various aspects of immune function in M. galloprovincialis, acting as stressor that can compromise the general welfare.

Effect of fluoranthene on antioxidative defense in different tissues of Lymantria dispar and Euproctis chrysorrhoea larvae

This study examined the effect of long-term exposure to environmentally relevant concentrations of dietary fluoranthene (6.7 and 67 ng / g dry food weight) on defense mechanisms of the polyphagous forest insects Lymantria dispar L. and Euproctis chrysorrhoea L. The activities and expression of isoforms of superoxide dismutase (SOD) and catalase (CAT), the activities of glutathione S-transferase (GST) and glutathione reductase (GR), and total glutathione content (GSH) were determined in the whole midgut and midgut tissue, while SOD and CAT activities were assessed in hemolymph of the larvae. The results showed significant changes of enzyme activities, with more pronounced responses in larval midgut tissues, and between-species differences in patterns of response. Significantly increased activity of SOD was recorded in the whole midgut and midgut tissue of L. dispar larvae, as well as in midgut tissue of E. chrysorrhoea larvae. Fluoranthene increased CAT activity in midgut tissue of L. dispar larvae, and in the whole midgut and midgut tissue of E. chrysorrhoea larvae. Different expression patterns were detected for enzyme isoforms in tissues of larvae exposed to dietary fluoranthene. Total GSH content and GST activity increased in E. chrysorrhoea larval midgut tissue. Significantly decreased SOD activity in hemolymph of L. dispar larvae, and opposite changes in CAT activity were recorded in the hemolymph of larvae of two insect species. The tissue-specific responses of enzymes to dietary fluoranthene, recorded in each species, enabled the larvae to overcome the pollutant induced oxidative stress, and suggest further assessment of their possible use as early-warning signals of environmental pollution.

Biomphalaria alexandrina: a model organism for assessing the endocrine disrupting effect of 17β-estradiol

A wide range of endocrine disruptor compounds are routinely discharged to the ecosystem. Water contaminated with these compounds has a potential effect on the reproductive physiology of aquatic organisms as well as humans. In the present study, we tested the effect of the steroid estrogen, 17β-estradiol, on Biomphalaria alexandrina, a snail species that is widely distributed in Egypt and that acts as an intermediate host for the human blood fluke, Schistosoma mansoni. The effects of exposure to 0.3 mg/L and 1 mg/L 17β-estradiol on fecundity (M_X) and reproductive rate (R₀) of B. alexandrina were recorded. In addition, levels of steroid sex hormones and antioxidants in the hemolymph and ovotestis (OT) of exposed snails were measured. Histopathological changes in the OT of B. alexandrina were also investigated. Exposure to 0.3 mg/L and 1 mg/L 17β-estradiol caused a significant increase in the number of egg masses per snail after 3 weeks and 1 week of exposure for the two tested concentrations compared with unexposed controls. An increase in the levels of progesterone hormone was recorded in the hemolymph of exposed snails in comparison with unexposed controls. Additionally, levels of the antioxidant enzyme glutathione (GSH) were increased in the hemolymph and OT tissues of snails after 2 and 4 weeks of exposure. Histopathological sections in the OT revealed an increase in the oocyte and a decrease in the sperm densities after 2 weeks and this effect was restored to normal conditions after 4 weeks of exposure to both tested concentrations. The current results indicate that B. alexandrina is sensitive to 17β-estradiol and can therefore be used as bioindicator and model organism for the assessment of water pollution with endocrine disruptor compounds.

Capsaicin-induced dysregulation of acid-base status in the American cockroach

Members of TRP receptor family are involved in response to acidification. Here, we determined the effect of capsaicin, one of the TRP receptor activators, on hemolymph acid-base status in the American cockroach. Periplaneta americana adult individuals were injected with lactic acid (5% or 10%) and exposed to 100 µM capsaicin solution. Hemolymph pH was measured 15 min, 1, 4, 8 and 24 h after lactic acid and capsaicin application with a glass microelectrode. The results demonstrated that cockroaches recover from acidosis within 4 h from acid injection. Capsaicin impaired the buffering capacity of insects' hemolymph, resulting in significant drop of hemolymph pH observed even 24 h after application. Joint action of capsaicin and acidosis reveals new insight into possible mechanism of capsaicin action on TRP receptors in insects.

Targeted metabolomics to investigate antimicrobial activity of itaconic acid in marine molluscs

INTRODUCTION

Itaconic acid (ITA) has recently been identified as an antimicrobial metabolite in mammalian immune cells. The presence of ITA was also reported in different tissues of marine molluscs, indicating its role as an endogenous metabolite of molluscs. In addition, the accumulation of ITA has been observed in different tissues of mussels following pathogen challenges. However, the concentration of ITA in mussel tissues and the possible role of this metabolite in the molluscan innate immune system remain unknown.

OBJECTIVES

This study aims to quantitatively measure ITA levels in different tissues of marine mussels following an experimental challenge with Vibrio sp. DO1 isolate, and to identify the antimicrobial role of ITA in the innate immune system through the measurement of metabolic and immune alterations in tissues following the challenge.

METHODS

In this study, adult Perna canaliculus mussels were experimentally challenged with a pathogenic Vibrio sp. DO1 isolate. The metabolite profiles of five different tissues, including mantle, gill, muscle, hepatopancreas and haemolymph were obtained, and levels of ITA in each tissue were characterized using a gas chromatography-mass spectrometry (GC-MS) metabolomics approach. Flow cytometry was also employed to measure cell health parameters, including oxidative stress via reactive oxygen species (ROS) production, apoptosis via changes in mitochondrial membrane potential (MMP) and haemocyte viability.

RESULTS

The ITA levels in mantle, gill, muscle and hepatopancreas tissues at 18-h post infection (hpi) with Vibrio sp. were 40.31, 41.71, 11.61 and 41.66 ng mg^-1, respectively. In haemolymph, the level of ITA was significantly increased from 95.25 ng ml^-1 at 6 hpi to 174.36 ng ml^-1 at 18 hpi and 572.12 ng ml^-1 at 60 hpi. In line with the accumulation of ITA, we observed increased levels of metabolites within the tricarboxylic acid (TCA) cycle, anti-inflammatory metabolites and alterations of other metabolites associated with immune responses of the host. The flow cytometry analyses revealed increases in ROS production, apoptotic cells and decreases in cell viability.

CONCLUSIONS

We reported on the production of ITA in different tissues of P. canaliculus mussels challenged with a marine pathogen which confirmed ITA as an antimicrobial metabolite. The findings revealed insights into the biosynthesis of ITA and suggests its role in antimicrobial and anti-inflammatory activities in the innate immune system. This study also provided insights into the innate immune system of bivalves and highlighted the potential use of ITA as a biomarker for shellfish health assessment in aquaculture.

Macro-elements in the hemolymph of adult Euschistus heros (Fabr.) (Hemiptera: Pentatomidae) treated with pyriproxyfen

Euschistus heros is an important pest in many crops in Brazil, and different control strategies, mainly involving chemicals, have been evaluated; however, the side effects of these chemicals on the balance of inorganic element levels in the hemolymph are unknown. Thus, the aim of this work was to determine the concentration of inorganic elements (focusing on macro-elements) in the hemolymph of female and male E. heros adults, after applying pyriproxyfen at a sublethal concentration (LC₃₀ = 6.68 mL L^-1 diluted in distilled water) to 4th instar nymphs, which were kept in controlled conditions. The hemolymph pool was removed 48 h after adult emergence, centrifuged and placed on an acrylic disk added with Gallium as internal standard for the analysis of total reflection X-ray fluorescence. Most of the elements in the control treatment did not differ between females and males. However, following insecticide application to females and males, respectively, there was a significant increase in sulfur (19 and 51%), chlorine (33 and 137%) and calcium (47 and 82%) in the hemolymph. The significantly higher increase in macro-elements in males' hemolymph indicates that the action of pyriproxyfen may be sex-specific. Phosphorus and potassium concentrations also differed between females and males in the control and treated groups. The observed variation in inorganic elements in the insect's hemolymph may be related to the unknown effects of pyriproxyfen, mainly on immune and reproductive performance.

A Vitellogenin Antibody in Honey Bees (Apis mellifera): Characterization and Application as Potential Biomarker for Insecticide Exposure

The insect yolk precursor vitellogenin is a lipoglycoprotein synthesized and stored in the fat body and secreted into the hemolymph. In honey bees, vitellogenin displays crucial functions in hormone signaling, behavioral transition of nurse bees to foragers, stress resistance, and longevity in workers. Plant protection products such as neonicotinoids, pyrethroids, and organophosphates alter the transcriptional expression of vitellogenin. To assess plant protection product-induced alterations on the protein level, we developed a rabbit polyclonal vitellogenin antibody. After characterization, we assessed its specificity and vitellogenin levels in different tissues of worker bees. The vitellogenin antibody recognized full-length 180-kDa vitellogenin and the lighter fragment of 150 kDa in fat body, hemolymph, and brain. In hemolymph, a band of approximately 75 kDa was detected. Subsequent mass spectrometric analysis (liquid chromatography-mass spectrometry) confirmed the 180- and 150-kDa bands as vitellogenin. Subsequently, we evaluated vitellogenin expression in brain, fat body, and hemolymph on 24-h exposure of bees to 3 ng/bee to the neonicotinoid clothianidin. Full-length vitellogenin was upregulated 3-fold in the fat body, and the 150-kDa fragment was upregulated in the brain of exposed honey bees, whereas no alteration occurred in the hemolymph. Upregulation of the vitellogenin protein by the neonicotinoid clothianidin is in line with the previously shown induction of its transcript. We conclude that vitellogenin might serve as a potential biomarker for neonicotinoid and other pesticide exposure in bees. Environ Toxicol Chem 2019;00:1-10. © 2019 SETAC.

Glyphosate affects haemocyte parameters in the clam Ruditapes philippinarum

This study was aimed at evaluating the effects of glyphosate on haemocyte parameters of the clam Ruditapes philippinarum. Clams were exposed for 7 days to differing glyphosate concentrations (10, 100 and 1000 μg/L) and various haemocyte parameters were measured, such as total haemocyte count (THC), haemocyte diameter and volume, haemocyte proliferation, haemolymph lactate dehydrogenase activity, haemocyte lysate lysozyme and acid phosphatase activities. Glyphosate reduced significantly THC values, while increased both diameter and volume of haemocytes. Exposure to the highest herbicide concentration increased significantly haemocyte proliferation. No significant effects on haemolymph lactate dehydrogenase and haemocyte lysate lysozyme activities were observed, whereas haemocyte lysate acid phosphatase activity resulted significantly increased in clams exposed at 100 and 1000 μg/L. On the whole, this study demonstrated that glyphosate influenced significantly haemocyte parameters in R. philippinarum.

Effects of soluble copper and copper oxide nanoparticle exposure on the immune system of mussels, Mytilus galloprovincialis

Copper and copper oxide nanomaterials (nCuO) can enter the marine environment negatively impacting mussels, an environmental and commercially relevant organism. We analyzed the effects on the immune system of adult mussels exposed to soluble copper (CuSO₄ , 20-50 μg/L) or nCuO (100-450 μg/L). CuSO₄ caused significant copper accumulation in gills and cell-free hemolymph, while nCuO caused cell damage to gills and significant copper accumulation in hemocytes, the most abundant cells in the hemolymph. Both sources of copper caused cellular toxicity in hemocytes by increasing reactive oxygen species production and lysosome abundance, and decreasing multi-drug resistance transporter activity. Though hemocyte abundance was not affected, their in-vitro phagocytic activity decreased, explaining the slight (but not statistically significant) increase in bacterial proliferation in mussels exposed to the pathogenic bacteria Vibrio tubiashii following copper exposure. Thus, exposure to non-lethal concentrations of CuSO₄ or nCuO can potentially increase mussel susceptibility to bacterial infections.

Exposure to 2,3,7,8-tetrachlorodibenzo-paradioxin (TCDD) hampers the host defense capability of a bivalve species, Tegillarca granosa

Though increasing reports of deleterious impacts of dioxins and polychlorinated biphenyls (PCBs) on a variety of marine organisms have been described, their effects on the host defense capability of marine bivalve mollusks remain poorly understood. In the present study we used 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a representative of dioxins and PCBs to investigate its impacts on the host defense capability of the blood clam, Tegillarca granosa. After exposure of clams to a range (0, 0.01, 0.1, 1, and 10 μg/L) of TCDD for 96 h, the total count, cell type composition, and phagocytic rate of haemocytes were analyzed. In addition, alkaline phosphatase (ALP) activity, cell viability, and the extent of DNA damage of haemocytes were also investigated. Our results showed that exposure to relatively high TCDD concentrations led to significant reductions in the total count and phagocytic activity of haemocytes, which could be accounted by aggravated DNA damage and reduced cell viability. In addition, the percentage of red granulocyte was significantly decreased whereas that of basophil granulocyte was significantly increased upon high doses TCDD exposure (effective concentrations are 1 μg/L and 10 μg/L for red and basophil granulocytes, respectively). Moreover, clams exposed to TCDD had a significant higher activity of ALP, may also indicate an enhanced ability to eliminate pathogens through direct dephosphorylation process whereas a suppressed inflammatory response through indirect regulating of downstream molecular cascade reaction. These findings suggest that TCDD may hamper the host defense capability and therefore render bivalve mollusks more vulnerable to pathogen infections.

Effect of dietary supplementation with apple cider vinegar and propionic acid on hemolymph chemistry, intestinal microbiota and histological structure of hepatopancreas in white shrimp, Litopenaeus vannamei

This experiment was conducted to evaluate the effects of dietary supplementation of Apple cider vinegar (ACV) and propionic acid (PA) on biochemical parameters of hemolymph, intestinal microbiota and histology of hepatopancreas in white shrimp (Litopenaeus vannamei). Five experimental diets were evaluated in this study including diets supplemented with 1.0, 2.0 and 4.0% of ACV, 0.5% propionic acid, and a control diet with no supplements. Shrimps (initial weight of 10.2 ± 0.04 g) in triplicate groups with the density of 25 shrimps per tank were fed the diets for 60 days. At the end of the feeding trial, shrimps fed with ACV and PA supplemented diets had significantly higher total protein level than those fed the control diet (P < 0.05). The number of Vibrio spp., R-cells (lipid storage cells) of hepatopancreas and cholesterol level in shrimps fed the diets containing ACV and PA were lower compared to the control group (P < 0.05). However, there was no remarkable variations in glucose concentration, B-cell number and tubule diameter among the experimental diets (P > 0.05). In addition, shrimps fed the ACV diets had significantly lower total heterotrophic marine bacteria compared to the control or PA groups, and the lowest bacterial number was observed in shrimp fed 4% ACV supplemented diet (P < 0.05). Supplementation of 2 and 4% ACV as well as 0.5% PA in the diet led to a significantly higher calcium concentration than the control treatment (P < 0.05). The lowest triglyceride concentration was observed in the shrimps fed diets containing 2.0 and 4.0% ACV, which resulted in 15 and 20% reduction, respectively (P < 0.05). Overall, the findings indicates that ACV and PA possess antimicrobial activity and demonstrate beneficial effects on health status, so they can be potentially used as feed additive in the feeding of L. vannamei.

Carbamazepine disrupts molting hormone signaling and inhibits molting and growth of Eriocheir sinensis at environmentally relevant concentrations

Carbamazepine (CBZ), one of the most frequently detected pharmaceutical compounds in aquatic environments, has recently been shown to cause chronic toxicity and endocrine disruption in a variety of non-target aquatic organisms. However, neither the effects nor the specific mechanism of CBZ action on the molting of crustaceans is well understood. The aim of this study was to investigate the effects of CBZ on the molting and growth of the Chinese mitten crab Eriocheir sinensis, a native and economically important species in China, and to elucidate the specific mechanisms through which molt inhibition occurs. Juvenile E. sinensis were treated with four nominal environmentally relevant concentrations (0.01, 0.1, 1, or 10 μg/L) of CBZ for acute (4 days) and chronic (40 days) exposures. After acute exposure, chitinase activity in the epidermis and 20-hydroxyecdysone (20-HE) concentration in the hemolymph were significantly decreased (p < 0.05) following treatment with 10 μg/L CBZ, whereas epidermal chitobiase activity significantly decreased (p < 0.05) in response to both 1 and 10 μg/L CBZ treatments. Transcript levels of the genes encoding crustacean hyperglycemic hormone (chh) and molt-inhibiting hormone (mih) in the eyestalks were also markedly induced after 1 or 10 μg/L CBZ treatment (p <  0.05), whereas the expression of genes encoding ecdysone receptor (ecr) and crustacean retinoid X receptor (rxr) in the hepatopancreas were significantly suppressed (p < 0.05) after acute exposure. Moreover, under chronic exposure, CBZ inhibited the molting and growth of E. sinensis, resulting in a longer time before molting was completed (TBM), as well as a lower molting increment (MI) with 1 or 10 μg/L treatment (p < 0.05). Collectively, these data indicate that CBZ can inhibit the molting process of E. sinensis by interfering with the activity of chitinolytic enzymes and molting hormone signaling, suggestive that carbamazepine may have long-term effects on crab development. We also confirmed that CBZ may function as an endocrine disruptor in decapod crustaceans, a phenomenon that has previously been reported in vertebrates.

Juvenile hormone controls ovarian development in female Anopheles albimanus mosquitoes

Anophelinae mosquitoes are vectors of human malaria, a disease that infects hundreds of millions of people and causes almost 600,000 fatalities annually. Despite their medical importance, laboratory studies on key aspects of Anophelinae reproductive biology have been limited, and in particular, relatively little is known about the role of juvenile hormone (JH) in the control of female reproduction. The study presented here attempts to fill a gap of knowledge in our understanding of the JH control of ovarian development in female Anophelinae mosquitoes, using Anopheles albimanus as a model. Our studies revealed that JH controls the tempo of maturation of primary follicles in An. albimanus in a similar manner to that previously described in Aedes aegypti. At adult eclosion JH hemolymph titer was low, increased in 1-day old sugar-fed insects, and decreased in blood fed individuals. JH titers decreased if An. albimanus females were starved, and were reduced if insects emerged with low teneral reserves, precluding previtellogenic ovarian development. However, absolute hemolymph titers were lower than Ae. aegypti. Decapitation experiments suggested that if teneral reserves are sufficient, factors from the head activate JH synthesis by the corpora allata (CA) during the first 9-12 h after adult emergence. In conclusion, our studies support the hypothesis that JH controls previtellogenic ovarian development in female An. albimanus mosquitoes, in a similar manner that have been described in Culicinae.

Isolation, characterization and mode of action of a larvicidal compound, 22-hydroxyhopane from Adiantum latifolium Lam. against Oryctes rhinoceros Linn

Oryctes rhinoceros Linn. is one of the most serious pests of coconuts and other palms. Following bioassay guided method, a larvicidal compound, 22-hydroxyhopane has been isolated for the first time from methanol extract of leaves of Adiantum latifolium Lam. against the pest (LC₅₀ value 20.81 μg/g). It is a hopanoid triterpene with molecular mass of 442.42 g/mol. The compound exhibited antibacterial activity against symbiotic gut bacteria, caused histolysis of midgut tissues and inhibited secretion of digestive enzymes such as protease, amylase and trehalase resulting in weight loss of larvae. Enzyme immunoassay showed an elevation of 20-hydroxyecdysone level in haemolymph causing disruption of metamorphosis of larvae.

Effects of aminomethylphosphonic acid, the main breakdown product of glyphosate, on cellular and biochemical parameters of the mussel Mytilus galloprovincialis

The effects of the breakdown products of herbicides on aquatic species are largely unknown. In a recent study, we evaluated the effects of glyphosate on the mussel Mytilus galloprovincialis. This study was designed to evaluate for the first time the impact of aminomethylphosphonic acid (AMPA) - the main breakdown product of glyphosate - on cellular and biochemical parameters of the mussel Mytilus galloprovincialis. Bivalves were exposed for 7, 14 and 21 days to 1, 10 and 100 μg/L of AMPA and various biomarkers were measured in haemolymph (total haemocyte counts, haemocyte diameter and volume, haemolymph pH, haemocyte proliferation, haemolymph lactate dehydrogenase activity, haemocyte lysate lysozyme and acid phosphatase activities), as well as in gills and digestive gland (superoxide dismutase, catalase, glutathione S-transferase and acetylcholinesterase activities). AMPA concentrations in seawater samples from the experimental tanks were also measured in order to correlate the biomarker responses of mussels with their exposure to the actual concentrations of AMPA. The MANOVA analysis demonstrated that the experimental variables considered (exposure dose, exposure duration, and their interaction) affected significantly biomarker responses. Nevertheless, the two-way ANOVA analysis revealed significant effects of AMPA on most of the biomarkers measured. The overall results of this study demonstrated that AMPA can affect cellular and biochemical parameters in mussels, similarly to glyphosate.

The use of carboxylesterases as biomarkers of pesticide exposure in bivalves: A methodological approach

Bivalves are worldwide sentinels of anthropogenic pollution. The inclusion of biomarker responses in chemical monitoring is a recommended practise that has to overcome some difficulties. One of them is the time frame between sample collection and sample processing in order to ensure the preservation of enzymatic activities. In the present study, three bivalve species of commercial interest (mussel, Mytilus galloprovincialis, razor shell, Solen marginatus, and cockle, Cerastoderma edule) were processed within <2 h after being retrieved from their natural habitat, and 24 h after being transported in air under cold conditions (6-8 °C) to laboratory facilities. The enzymatic activities were compared in the three species submitted to both conditions revealing no differences in terms of carboxylesterase dependent activities (CEs) using different substrates: p-nitrophenyl acetate (pNPA), p-nitrophenyl butyrate (pNPB), 1-naphthyl acetate (1-NA), 1-naphthyl butyrate (1-NB) and 2-naphthyl acetate (2-NA). In mussels, three tissues were selected (haemolymph, gills and digestive gland). For comparative purposes, in razor shell and cockle only digestive gland was considered as it is the main metabolic organ. Baseline enzymatic activities for CEs were characterised in the digestive gland of the three bivalves using four out of the five selected CE substrates as well as the kinetic parameters (V_max and K_m) and catalytic efficiency. The in vitro sensitivity to the organophosphorus metabolite chlorpyrifos oxon was also calculated. IC₅₀ values (pM-nM range) were lower than those obtained for vertebrate groups which suggest that bivalves have high protection efficiency against this pesticide as well as species dependent particularities.

Oxidative stress and genotoxic effect of deltamethrin exposure on the Chinese mitten crab, Eriocheir sinensis

The oxidative stress and genotoxic effect of deltamethrin on the Chinese mitten crab Eriocheir sinensis were assessed using several commonly used biomarkers in this study. The results showed that the 48 h and 96 h LC₅₀ values of deltamethrin to E. sinensis were 2.319 and 1.164 μg/L, respectively, and the safe concentration was 0.293 μg/L. According to these results, deltamethrin was applied at concentrations of 1/16, 1/8, 1/4, 1/2 and 1/1 96 h LC₅₀ for 8 d in an exposure experiment. The activity of superoxide dismutase (SOD) increased remarkably at 1 d, but decreased at 4 d in concentration group of 1/4, 1/2 and 1/1 LC50, whereas catalase (CAT) activity decreased during the exposure. The total antioxidant capacity (T-AOC) at the concentrations of 1/4, 1/8 and 1/16 LC50 increased significantly at 1 d or 2 d respectively, whereas it decreased gradually until the end of the experiment under the concentrations above 1/4 LC50. The oxidative stress products malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) in serum increased significantly at each concentration except H₂O₂ at concentration of 1/16 LC50. Additionally, the micronucleus (MN) frequency of haemocytes increased at the concentrations of 1/4, 1/2 and 1/1 LC50 throughout the exposure, similar trend was observed in the comet ratio and percentage of tail-DNA (%DNA) in haemocytes. These results revealed that deltamethrin had a prominent toxic effect on E. sinensis based on antioxidative response inhibition and genotoxicity that was possibly due to lipid peroxidation (LPO) induced by oxidative products, and the accumulation of peroxide, even under a sublethal concentration.

Effects of nanosilver on Mytilus galloprovincialis hemocytes and early embryo development

Silver nanoparticles (AgNP), one of the main nanomaterials for production and use, are expected to reach the aquatic environment, representing a potential threat to aquatic organisms. In this study, the effects of bare AgNPs (47 nm) on the marine mussel Mytilus galloprovincialis were evaluated at the cellular and whole organism level utilizing both immune cells (hemocytes) and developing embryos. The effects were compared with those of ionic Ag⁺(AgNO₃). In vitro short-term exposure (30 min) of hemocytes to AgNPs induced small lysosomal membrane destabilization (LMS EC₅₀ = 273.1 μg/mL) and did not affect other immune parameters (phagocytosis and ROS production). Responses were little affected by hemolymph serum (HS) as exposure medium in comparison to ASW. However, AgNPs significantly affected mitochondrial membrane potential and actin cytoskeleton at lower concentrations. AgNO₃ showed much higher toxicity, with an EC₅₀ = 1.23 μg/mL for LMS, decreased phagocytosis and induced mitochondrial and cytoskeletal damage at similar concentrations. Both AgNPs and AgNO₃ significantly affected Mytilus embryo development, with EC₅₀ = 23.7 and 1 μg/L, respectively. AgNPs caused malformations and developmental delay, but no mortality, whereas AgNO₃ mainly induced shell malformations followed by developmental arrest or death. Overall, the results indicate little toxicity of AgNPs compared with AgNO₃; moreover, the mechanisms of action of AgNP appeared to be distinct from those of Ag⁺. The results indicate little contribution of released Ag⁺ in our experimental conditions. These data provide a further insight into potential impact of AgNPs in marine invertebrates.

Gold Octahedra nanoparticles (Au_0.03 and Au_0.045): Synthesis and impact on marine clams Ruditapes decussatus

The increased use of gold nanoparticles (AuNPs) in several applications has led to a rise in concerns about their potential toxicity to aquatic organisms. In addition, toxicity of nanoparticles to aquatic organisms is related to their physical and chemical properties. In the present study, we synthesize two forms of gold octahedra nanoparticles (Au__0.03 and Au__0.045) in 1.3-propandiol with polyvinyl-pyrrolidone K₃₀ (PVPK₃₀) as capping agent using polyol process. Shape, size and optical properties of the particles could be tuned by changing the molar ratio of PVP K₃₀ to metal salts. The anisotropy in nanoparticles shape shows strong localized surface plasmon resonance (SPR) in the near infrared region of the electromagnetic spectrum. Environmental impact of Oct-AuNPs was determined in the marine bivalve, Ruditapes decussatus exposed to different concentrations of Au__0.03 and Au__0.045. The dynamic light scattering showed the stability and resistance of Au__0.03 and Au__0.045 in the natural seawater. No significant modification in vg-like proteins, MDA level and enzymatic activities were observed in treated clams with Au__0.03 even at high concentration. In contrast, Au__0.045 induced superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST) activities, in a concentration dependent manner indicating defense against oxidative stress. Enhanced lipid peroxidation represented by malondialdehyde content confirmed oxidative stress of Au__0.045 at high concentration. These results highlight the importance of the physical form of nanomaterials on their interactions with marine organisms and provide a useful guideline for future use of Oct-AuNPs. In addition, Vitellogenin is shown not to be an appropriate biomarker for Oct-AuNPs contamination even at high concentration. We further show that Oct-AuNPs exhibit an important antioxidant response without inducing estrogenic disruption.

Regulation of hemolymph trehalose titers by insulin signaling in the legume pod borer, Maruca vitrata (Lepidoptera: Crambidae)

A disaccharide, trehalose, is a main hemolymph sugar of the legume pod borer, Maruca vitrata larvae, but its titers fluctuated with feeding activity. During diurnal feeding in the photophase, hemolymph trehalose remained at a relatively low level (69 mM) and increased (98 mM) during scotophase. Starvation significantly increased the hemolymph trehalose level, in which the elevation of trehalose titers was dependent on the non-feeding period. The down-regulation of the trehalose level during the active feeding period seemed to result from mediation of the insulin/IGF signal (IIS). Injection of a porcine insulin suppressed the trehalose level in a dose-dependent manner. Genes associated with IIS of M. vitrata were predicted from its larval transcriptome, and their expression was confirmed in different developmental stages and tissues. All seven IIS genes selected were expressed in all developmental stages and different tissues. Silencing of four IIS genes (insulin receptor, Forkhead box O, a serine-threonine protein kinase, target of rapamycin) by RNA interference significantly modulated the hemolymph trehalose level. Starvation treatment changed expression of two trehalose metabolism-associated genes (trehalose phosphate synthase (TPS) and trehalase (TRE)) as well as the IIS genes. Silencing of TPS or TRE expression significantly down- or up-regulated the hemolymph trehalose level, respectively. In addition, silencing of IIS genes altered both TPS and TRE expression, indicating a functional link between IIS and trehalose metabolism. These results suggest that nutrients obtained from feeding activate IIS of M. vitrata, which then down-regulates the hemolymph trehalose level by altering trehalose metabolism.

Histopathological effects of Pedunsaponin A on Pomacea canaliculata

Pedunsaponin A, a novel molluscicidal compound isolated from Pueraria peduncularis, exhibits strong toxicity against Pomacea canaliculata. To determine the mechanisms of Pedunsaponin A toxicity, its effects on the organs and hemocytes of P. canaliculata were examined in this study. The results showed that Pedunsaponin A had significant toxic effects on different organs of the snail, including the lungs, gills, mantle, siphon tube, ventricle, pericardial cavity, hepatopancreas, kidneys, and the major symptom of this toxicity was the loss of cilia in the lungs and gills. Additionally, in further studies on the effects of Pedunsaponin A treatment, we found that the hemocyte count was changed and hemocyte morphology was damaged, which was primarily reflected by cytoplasm leakage, nuclei deformation, and significant reductions in the number of ribosomes and granulocyte mitochondria. Based on these results and considering that blood vessels are distributed in the lungs and gills, we hypothesized that Pedunsaponin A would first destroy the cilia, which disrupt physiological activities such as respiration, excretion and feeding, and then enter the hemolymph through blood vessels, disrupt the normal function of the hemocytes and destroy the snail immune system, eventually resulting in the death of the snail.

Selection of reference genes for quantitative real-time PCR in Octopus minor (Cephalopoda: Octopoda) under acute ammonia stress

High concentration of ammonia is a common issue in the aquaculture industry and often causes detrimental effects to aquatic products. Exploring expression regulation of genes involved in acute ammonia stress can help to understand the molecular mechanisms of ammonia response. Quantitative real-time PCR (qRT-PCR) with proper reference genes is an effective way to normalize the expression of target genes. To identify the most suitable reference genes for Octopus minor (Mollusca: Cephalopoda: Octopoda) under acute ammonia stress and the normal culturing, nine candidate genes were selected for the validation: OD, RPS18b, RPL29, RPS5, EF-1α, RPL6, AA4, ACT, TUB. The results showed that the stability of candidate genes varied considerably in gill, digestive gland, brain and hemolymph. Thus, the reference genes were determined separately in different tissues. RPS5 and RPL6 showed relatively high stability in gill, while RPL6, TUB, RPL29 and OD were four suitable reference genes in digestive gland. EF-1α, TUB and RPL6 were the best combination in brain and EF-1α and RPS18b were the most appropriate reference genes in hemolymph.

Effects of atrazine on vitellogenesis, steroid levels and lipid peroxidation, in female red swamp crayfish Procambarus clarkii

Atrazine, a widely use herbicide, has been classified as a potential endocrine disruptor, especially for freshwater species. In this study, we tested the hypothesis that atrazine can affect reproduction in crayfish through dysregulation of vitellogenin expression and hormone synthesis. Adult female crayfish (Procambarus clarkii) were exposed during one month to atrazine at concentrations of either 1 or 5 mg/L. At the end of the exposure, ovaries, hepatopancreas, and hemolymph samples were harvested for analysis of vitellogenin expression and steroid hormone levels. Ovarian tissue was also sampled for both biochemical and histological analyses. Our results show that atrazine-exposed crayfish had a lower expression of vitellogenin in the ovary and hepatopancreas, as well as smaller oocytes, and reduced vitellogenin content in the ovary. Despite these effects, circulating levels of estradiol increased in females exposed to 5 mg/L of atrazine, showing that the inhibiting effect of atrazine on vitellogenin production was not related to a lower secretion of sexual steroids. Instead, some early stimulating effects of estradiol on vitellogenesis could have occurred, particularly in the hepatopancreas. On the other hand, atrazine caused a higher metabolic effort, in terms of lactate production, presumably triggered to provide the energy needed to face the unspecific stress produced by the herbicide. Lipid peroxidation was not affected by atrazine, but glutathione levels were significantly increased.

Effects of food contaminated with cadmium and copper on hemocytes of Steatoda grossa (Araneae: Theridiidae)

The aim of this study was to evaluate the metabolic condition of Steatoda grossa (Theridiidae) spider, from their hemocytes, after a short-term (four-week) exposure to cadmium and copper in sublethal doses by administering them into the body of the preys. The ultrastructure of the dominant types of hemocytes, such as granulocytes, plasmatocytes and prohemocytes, was evaluated using transmission electron microscope (TEM). Quantitative evaluation of apoptotic and necrotic cells, as well as the ones with depolarized mitochondria in hemolymph, was performed using flow cytometry, while ATP concentration and ADP/ATP ratio in hemocytes were measured by luminescent methods. Cadmium, unlike copper, demonstrated proapoptotic and pronecrotic activity. Low ATP levels and high ADP/ATP ratio in hemocytes indicate a disturbance in the energy metabolism of cells and may account for their qualitative and quantitative degenerative changes. The intensification of death processes in hemocytes after an exposure to cadmium-contaminated food may impair the ability of these cells to fight infectious diseases. Copper at the applied dosage was safe for the spiders without causing visible changes in the hemocyte ultrastructure and in the level of analyzed cell death indices.

Effects of fluorine-containing usnic acid and fungus Beauveria bassiana on the survival and immune-physiological reactions of Colorado potato beetle larvae

BACKGROUND

The search for compounds that interact synergistically with entomopathogenic fungi is aimed at enhancing the efficacy and stability of biological products against pest insects, for example, against the Colorado potato beetle (CPB). We hypothesized that fluorine-containing derivatives of usnic acid (FUA) might be candidates for the development of multicomponent bio-insecticides. The aim of this study was to analyze the co-influence of FUA and Beauveria bassiana on the survival and immune-physiological reactions of CPB larvae.

RESULTS

Synergy between FUA and B. bassiana was observed after treatment of second, third and fourth larvae instars under laboratory conditions. Furthermore, synergy was observed in field trials in continental climate conditions in southeastern Kazakhstan. In a field experiment, the median lethal time was shortened three-fold, and cumulative mortality for 15 days increased by 36% in the combined treatment compared with a fungal infection alone. FUA treatment delayed larval development, decreased the total hemocyte count, and increased both the phenoloxidase activity in integuments and the detoxification enzyme rate in hemolymph. A combined treatment with fungus and FUA led to increases in the aforementioned changes.

CONCLUSION

Toxicosis caused by FUA provides a stable synergistic effect between FUA and B. bassiana. The combination can be promising for the development of highly efficient products against CPB. © 2017 Society of Chemical Industry.