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Dactylogyrus is one of the most common parasitic diseases in fish and causes huge losses to the aquaculture industry. With the advantages of safety, low toxicity and easy degradation, plant‐derived drugs are ideal for the creation of green aquatic ingredients. The use of plant‐derived drugs in aquaculture is limited by their low content and high processing costs, which is a challenge that can be solved by the chemical synthesis of plant‐derived drugs. Eleven new coumarin derivatives were synthesized and assessed for their anthelmintic activity in this study. Among them, the derivative 7‐((1‐tosyl‐1H‐1,2,3‐triazol‐4‐yl)methoxy)‐2H‐chromen‐2‐one (N11) has good anthelmintic activity and its mean anthelmintic efficacy against D. intermedius at a concentration of 10 μM reached 99.84%, which is even better than the anthelmintic activity of the positive control mebendazole. Further studies showed that N11 had concentration values of 3.31 and 1.94 μM for 50% maximal effect (EC50) against D. intermedius at 24 and 48 h, respectively. Furthermore, scanning electron microscopy revealed that N11 caused damage to D. intermedius. What is more noteworthy is that a substantial reduction in the ATP content of the parasite was observed following in vitro and in vivo administration of N11. Moreover, it was also found that N11 was able to inhibit the horizontal transmission of D. intermedius. Furthermore, real‐time quantitative PCR analysis was utilized to determine the expression profile of genes associated with anti‐inflammatory cytokines (IL‐10, TGF‐β and IL‐4) in goldfish. In all examined organs, it was observed that the expression of anti‐inflammatory cytokines increased subsequent to treatment with N11, according to the results. Thus, these results all suggest that N11 possesses good anthelmintic activity and is a potentially effective agent for the control of D. intermedius. [ABSTRACT FROM AUTHOR]

Infectious hematopoietic necrosis (IHN) caused by the viral pathogen infectious hematopoietic necrosis virus (IHNV) is a highly contagious disease of salmonid species, resulting in significant economic impact. The previous study showed a hydroxycoumarin derivative 7-[6-(2-methylimidazole) hexyloxy] coumarin (D5) significantly inhibited spring viraemia of carp virus (SVCV) infection, suggesting that D5 may be useful as a potential anti-IHNV agent. In this study, D5 at the concentration of up to 10 mg/L significantly inhibited IHNV replication in epithelioma papulosum cyprini (EPC) cells with a maximum inhibitory rate of >90%, maintained mitochondrial membrane potential (ΔΨm) levels, and decreased IHNV-induced apoptosis in virus-infected cells. As the consequence of protection on mitochondria, D5 enhanced antioxidant enzyme activities and decreased reactive oxygen species (ROS) to maintain the antioxidant-oxidant balance of IHNV-infected EPC cells. For in vivo study, D5 via intraperitoneal injection exhibited an anti-IHNV effect in the virus-infected fish by substantially enhancing the survival rate. Meanwhile, up-regulation of six interferon (IFN) related gene expressions demonstrated that D5 may activate IFN-related expressions for inhibiting IHNV replication during the early stage of viral infection, which is beneficial for the continuous antiviral action on controlling low viral loads in rainbow trout juvenile. Thus, D5 effective regulated IHNV-induced undesirable conditions to be an excellent potential therapeutic agent against IHNV infection. • A coumarin (D5) effectively inhibits IHNV replication in vitro and in vivo. • D5 disturbs IHNV binding to EPC cells. • D5 triggers IFNs-related gene expression against IHNV in fish. • D5 may be suitable as a possible therapeutic agent for IHNV infection. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are widely used in industrial and commercial applications, but few studies systematically evaluate their developmental toxicity on aquatic organism. Using rare minnow ( Gobiocypris rarus) at early life stages as experimental models, developmental toxicity of functionalized single-walled CNTs (SWCNTs) was investigated following exposure to 0-320 mg/L for 144 h. Results revealed that significantly increased in mortality and malformation was only observed after hatching. Decreased body length, heart rate and swimming speed provide a concentration-dependent manner on larvae; values of 144 h LC50 and EC50 were 140.8 and 109.8 mg/L, respectively. Antioxidant enzyme activities (superoxide dismutase, catalase and glutathione S-transferase) and antioxidant enzyme related mRNA expressions were significant changed; cell apoptosis activities (caspase-3, -8, -9) and cell apoptosis related mRNA expressions were significant up-regulated; reactive oxygen species and DNA damage were significantly induced when the concentration of SWCNTs above 100 mg/L. Fluorescence and electron microscopy sliced observation show that SWCNTs were well dispersed in larvae within 0.5 h, eventually cleared from the larvae at 144 h. This is the first study to define uptake kinetics and to focus on behavioral consequences, physiological changes and mRNA expression following SWCNTs exposure in the early life stages of fish. The results obtained in the present study demonstrated that functionalized SWCNTs have the potential to affect aquatic life when released into the aquatic environment and reached high concentration. In the increasing economical context of SWCNTs, complementary studies must be undertaken, especially including mechanistic and environmental investigations. [ABSTRACT FROM AUTHOR]

Due to the high chemical and photochemical stability, an organophosphorus pesticide triazophos might enter aquatic ecosystems and impose negative effect on aquatic organisms. In order to investigate short-term toxicity of triazophos on goldfish ( Carassius auratus ), antioxidant response in brain, spleen, kidney and liver was tested in this study. As a confirmation, the impact of triazophos on acetyl cholinesterase (AChE) activity was found a reduction in all studied tissues, especially in brain. In addition, 0.1 and 0.5 mg L −1 triazophos induced MDA level increased, while glutathione content (GSH), superoxide dismutase (SOD), catalase (CAT) and lactate dehydrogenase (LDH) activities decreased. Of note, more prominent oxidative stress was provoked in kidney and liver, but weaker in brain and spleen. These results revealed that triazophos could cause a generalized oxidative stress and tissue specific antioxidant response in goldfish. Furthermore, neuroendocrine-growth-related gene expression (growth hormone (GH), luteinizing hormone (LH) and peptide YY) in brain was also changed by exposed to triazophos during 4 and 7 d exposure periods. Linked with the above results, the present study pointed out that triazophos might induce a neurotoxic effect and oxidative damage in goldfish, and the goldfish brain should be a critical target for triazophos-induced damage. [ABSTRACT FROM AUTHOR]

Trifloxystrobin (TFS) is the widely used strobilurin fungicide. However, little information is so far available regarding the uptake kinetics and developmental toxicity of TFS to fish. The present study was conducted to investigate the uptake kinetics, potential environment risk and toxicity of TFS on Gobiocypris rarus embryos. Results revealed that increased malformation, decreased body length and heart rate, affected spontaneous movement and swimming speed provide a gradual concentration-dependent manner; values of 144 h LC 50 (median lethal concentration) and EC 50 (median effective concentration) were 1.11 and 0.86 μg L −1 . Continuous exposure to TFS resulted in a steady accumulation with no evidence of elimination. Enzyme activities were significantly changed; reactive oxygen species and DNA damage were significantly induced after TFS treatment. Certain genes related to cell apoptosis ( p53 ), metabolism ( cyp1a ), stress response ( hsp70 ) and blood vessels ( vezf1 ) development were all significantly up-regulated. This is the first study to define uptake kinetics and to focus on behavioral consequences, physiological changes and mRNA expression following TFS exposure in the early life stages of fish. Our results suggest that TFS is highly toxic to fish embryos. [ABSTRACT FROM AUTHOR]

As a serious parasitic pathogen in aquaculture, Dactylogyrus has a serious economic impact on freshwater and marine farmed fish. Due to the high affinity and specificity for various molecular targets, coumarins are considered advantageous for the design of novel agents. In this study, we designed and synthesized a total of 44 coumarin derivatives and evaluated the antiparasitic activity against D. intermedius in goldfish. The results showed that the majority of coumarin derivatives exhibited efficient anthelmintic activity with concentration for 50% of maximal effect (EC 50) values of 1 mg/L to 10 mg/L. Structure-activity relationship analysis indicated that a nitrogen heterocyclic substituent and long coumarin linkers could result in a synchronous enhancement of antiparasitic activity and toxicity. Further data indicated that the large proportion of substituent space on the fourth carbon atom of coumarin ring reduced the anthelmintic efficacy of derivatives, while the methyl substituent may increase medicine toxicity to goldfish, which contributed to improving drug potency and reducing toxicity in future studies. In addition, the result of the therapeutic index (TI) value greater than 5 reflected that five 7-hydroxycoumarin derivatives, serial numbers A11 , A10, A9, A1 and A2 , exhibited higher potential prospects than other coumarins in preventing and controlling Dactylogyrus infections. Thus, we suggest that the related coumarins represent potentially effective therapeutic agents against D. intermedius in aquaculture species. • A total of 44 coumarins were synthesized for evaluation on their anti- Dactylogyrus activity. • Five 7-hydroxycoumarin derivatives have a maximum therapeutic index more than 5. • The methyl substituent on the fourth carbon atom of the coumarin ring only increased the toxicity of coumarins. • The nitrogen heterocyclic substituent synchronously increased antiparasitic activity and toxicity of coumarins. [ABSTRACT FROM AUTHOR]

• A phenylpropanoid derivative E2 was evaluated for the anti-SVCV activity. • Drug cure effect showed that treatment with E2 at 0.5 dpi is more effective than at 0, 1 or 2 dpi. • E2 suppresses SVCV replication in fish by up-regulation of interferon-related gene expressions. Phenylpropanoids, common natural compounds, possess many different biological activities such as antioxidant, anti-inflammatory and antiviral. Spring viraemia of carp virus (SVCV) can cause a high mortality in common carp (Cyprinus carpio). However, there are currently no licenced drugs that effectively cure this disease. In this study, we designed and synthesized a phenylpropanoid derivative 4-(4-methoxyphenyl)-3,4-dihydro-2H-chromeno[4,3-d]pyrimidine-2,5(1 H)-dione (E2), and explored the antiviral effect against SVCV in vitro and in vivo. Up to 25 mg/L of E2 significantly inhibited the expression levels of SVCV protein genes in the epithelioma papulosum cyprini (EPC) cell line by a maximum inhibitory rate of >90%. As expected, E2 remarkably declined the apoptotic of SVCV-infected cells and suppressed potential enhancement of the mitochondrial membrane potential (ΔΨm), these data implied that E2 could protect mitochondria from structural damage in response to SVCV. Meanwhile, E2 was added to EPC cells under four different conditions: time-of-addition, time-of-removal, pre-treatment of viruses and pre-treatment of cells indicated that E2 may block the post-entry transport process of the virus. Additionally, the up-regulation of six interferon (IFN)-related genes also demonstrated that E2 indirectly activated IFNs for the clearance of SVCV in common carp. Drug cure effect showed that treatment with E2 at 0.5 d post infection (dpi) is more effective than at 0, 1 or 2 dpi. Most importantly, intraperitoneal therapy of E2 markedly improved common carp survival rate and reduced virus copies in body. Therefore, the E2 has potential to be developed into a novel anti-SVCV agent. [ABSTRACT FROM AUTHOR]

To reduce the economic losses caused by diseases in aquaculture industry, more efficient and economic prophylactic measures should be urgently investigated. In this research, the effects of a novel functionalized single-walled carbon nanotubes (SWCNTs) applied as a delivery vehicle for DNA vaccine administration in juvenile grass carp against Aeromonas hydrophila were studied. Our results showed that SWCNTs loaded with DNA vaccine induced a better protection to juvenile grass carp against A. hydrophila . Moreover, SWCNTs conjugated with DNA vaccine provided significantly protective immunity compared with free DNA vaccine. Thereby, SWCNTs may be considered as a potential efficient DNA vaccine carrier to enhance the immunological activity. [ABSTRACT FROM AUTHOR]

Abstract Based on long-term monitoring conducted in Chang-ning county, a pilot site of the ‘Grain for Green Program’ (GFGP), an integrated emergy and economic method was applied to evaluate the dynamic ecological-economic performance of 3 kinds of bamboo systems planted on sloping farmland. The results confirmed the positive effects of all 3 kinds of bamboo systems on water conservation and soil erosion control. The benefits gained progressively increased during the first 8 years after conversion, going from 4639 to 16127 EMyuan/ha/yr on average. All three bamboo plantations were much more sustainable than common agricultural crops planted on sloping land (CP) on both the short and long-term scales with their Emergy Sustainability Index (ESI) and Emergy Index for Sustainable Development (EISD), respectively, being 14.07–325.71 and 80.35–265.80 times that of CP. However, all 3 bamboo plantations had a Net Economic Benefit (NEB) less than that of CP during the first 8 years after conversion. Even with the government-mandated ecological compensation applied, the annual NEB EC s of the Bambusa rigida (BR) and Phyllostachys pubescense (PP) plantations were, respectively, 3922.03 and 7422.77 yuan/ha/yr lower than the NEB of CP. Emergy-based evaluation of ecosystem services provides an objective reference for applying ecological compensation in strategy-making, but it cannot wholly solve the economic viability problem faced by all bamboo plantations. Inter-planting annual herbs or edible fungus, such as Dictyophora echinovolvata, within bamboo forests, especially in young bamboo plantations, might be a direction for optimizing bamboo cultivation that would improve its economic viability. [ABSTRACT FROM AUTHOR]

Current chemotherapy of mono-component for Dactylogyrus is unsatisfactory due to its limited efficacy with side effects including pesticide resistance and drug residue. The present study is conducted to investigate the effects of herbal ingredients combination against Dactylogyrus on Carassius auratus under in vivo conditions. The ingredients of Dioscorea zingiberensis ( D. zingiberensis ) and Ginkgo biloba ( G. biloba ) are administered individually and in combination in an experimental fish infection model in this study. Finally, strong synergy actions are observed in both the methanol extract combinations and the active compound combinations between D. zingiberensis and G. biloba . The anthelmintic effects of the combination are expressed in terms of the values of EC 50 , EC 75 , EC 90 , and EC 99 to compare with the phytomedicine alone. The combination index (CI) is also calculated by using the combination index algorithm. Both the values of effective concentration and combination index indicate a highly synergistic anthelmintic effect against Dactylogyrus . Our study provides a powerful means by which anthelmintic combination therapies can be examined and demonstrates that the combinations of herbal ingredients have excellent properties and are predicted to give improved cure rates in monogenean management of aquaculture. [ABSTRACT FROM AUTHOR]

Highlights: [•] Trifloxystrobin can inhibit the growth of Chlorella vulgaris. [•] Trifloxystrobin may influence cell membrane permeability. [•] The photosynthesis-energy-related gene expressions are changed. [•] Antioxidant enzyme activities were decreased. [•] Increase of oxidative stress in algal cells. [Copyright &y& Elsevier]

Highlights: [•] New methods for the controlling harmful cyanobacterial blooms are urgent. [•] A new algicidal compound from Salvia miltiorrhiza Bung was isolated and identified. [•] Neo-przewaquinone A destroyed the M. aeruginosa cell structure. [•] Neo-przewaquinone A induced oxidative damage of M. aeruginosa. [•] Neo-przewaquinone A reduced expression of the photosynthesis-related genes. [Copyright &y& Elsevier]

Due to the lack of relevant therapies for infectious haematopoietic necrosis virus (IHNV) infection, the viral outbreak invariably causes serious economic losses in salmonid species. In this study, we evaluated the anti-IHNV effects of 7-(6-benzimidazole) coumarin (C10) and 4-phenyl-2-thioxo-1,2,3,4-tetrahydro-5H-chromeno[4,3-d]pyrimidin-5-one (S5) in vitro and in vivo. The results revealed that C10 at 12.5 mg/L and S5 at 25 mg/L significantly inhibited IHNV replication in epithelioma papulosum cyprini (EPC) cells with a maximum inhibitory rate >90%, showing that IHNV-induced cytopathic effect (CPE) was alleviated by C10 and S5. There are two complementary effects on antiviral mechanism: 1. C10 completely inhibited IHNV infectivity when the virus was preincubated with C10 at 12.5 mg/L, determining that C10 may have a negative impact on IHNV binding to the cell; 2. C10 also up-regulated the gene expression of extracellular proto type galectin-1 (Gal1-L2) and a chimera galectin-3 (Gal3-L1) of EPC cells to inhibit IHNV adhesion. For the in vivo study, injection and immersion of the coumarins enhanced the survival rate of rainbow trout (Oncorhynchus mykiss) juveniles by 25% (at least) at 12 dpi. IHNV loads in the kidney and spleen were also obviously decreased at 96 h, and thus we considered that they had a delaying effect on IHNV replication in vivo. Meanwhile, C10 with a high stability in aquacultural water in immersion suppressed IHNV horizontal transmission by decreasing the viral loads in recipient fish. Overall, our data suggest that there is a positive effect of C10 and S5 against IHNV infection in aquaculture, and C10 had the potential to be a broad-spectrum antiviral against fish rhabdoviruses. • C10 is a potential broad-spectrum antiviral for controlling rhabdovirus. • C10 and S5 have a delaying effect against IHNV replication in vivo. • C10 may reduce the risk of IHNV transmission. • C10 inhibits IHNV adhesion to cell surface. [ABSTRACT FROM AUTHOR]

Spring viremia of carp virus (SVCV) is a highly pathogenic sprivivirus that continues to cause outbreaks in cyprinidae characterized by high mortality. Currently, few therapeutics have approved for use in aquaculture against SVCV infection. Previously, we reported that 4-(2-methoxyphenyl)-3,4-dihydro-2H-chromeno[4,3-d] pyrimidine-2,5(1H)-dione-phenylpropanoid (S3) inhibits SVCV proliferation. It was first appeared in the S5 series of compounds. Compared with S5, S3 is easier to synthesize and has a higher yield. Here, in order to further evaluate the practical application potential of S3 in aquaculture, common carp as a model organism was carried out relevant experiments. In this study, we evaluated toxicity of S3 in vivo. The results showed that the dose below 100 μg/mL is safe, and there was a significant toxicity if it exceeds this dose. In pathogenicity tested of SVCV, the 50% lethal dose (LD 50) of the present SVCV isolate to present common carp was approximately 101.6-fold TCID 50 /fish. Subsequently, further data suggested that S3 was stability with a prolonged inhibitory half-life in the early stage of virus infection (1–4 days). Importantly, intraperitoneal (i.p.) therapy of S3 markedly decreased fish mortality and reduced virus copies in both spleen and kidney. Mechanically, S3 enhanced the levels of IFN-related genes demonstrated that S3 indirectly activated IFNs for the clearance of SVCV in common carp. Additionally, the results of HE staining showed that S3 may be able to attenuate inflammation symptoms in SVCV infected fish. Therefore, the phenylpropanoid derivative S3 has potential to be used as an anti-SVCV therapeutics against fish viral diseases. [Display omitted] • We obtained compound S3 from the small molecule drug library. • S3 is easy to synthesize, has high yield and low toxicity in vivo , making it more promising for practical applications. • S3 interfering SVCV infection in common carp is attributed to enhancement of IFNs responses. • HE staining showed that S3 may be able to attenuate symptoms in SVCV infected fish. [ABSTRACT FROM AUTHOR]

Due to no treatment available to interfere with the unrestrained outbreak and spread of white spot syndrome virus (WSSV), the virus results in a serious economic losses in shrimp industry. Here, a novel amino-nitrophenyl coumarin derivative 2-amino-4-(4-nitrophenyl)-5-oxo-4H, 5H-pyrano[3,2- c ]chromene-3-carbonitrile (C3007) was evaluated for anti-WSSV effect in Litopenaeus vannamei larvae. The data demonstrated that WSSV replication was suppressed over 95% in the presence of 10 mg/L C3007 for 72 h infection. As a response, the mortality of WSSV-infected larvae was decreased more than 50%. After WSSV infection for 24 h, continuous updated immersion of C3007 resulted in the mortality further reduced additional 20%. Additionally, the data that horizontal transmission in a cohabitation was significantly inhibited by C3007 revealed may reduce the risk of virus transmission in shrimp seedling culture. We believe that C3007 is suitable for inhibiting WSSV transmission in static aquaculture systems. These results suggested C3007 can be used as a potential agent to treat and prevent WSSV infection in aquacultural shrimp industry. • A potential broad-spectrum antiviral C3007 protects shrimp larvae from WSSV infection. • Continuous exchange of C3007 further inhibits WSSV replication in shrimp larvae. • C3007 may be of great benefit to culture of shrimp seedling. [ABSTRACT FROM AUTHOR]

Spring viremia of carp virus (SVCV) causes devastating losses in aquaculture. Coumarin has an advantageous structure for the design of novel antiviral agents with high affinity and specificity. In this study, we evaluated a hydroxycoumarin medicine, i.e., 7-(6-benzimidazole) coumarin (C10), regarding its anti-SVCV effects in vitro and in vivo . Results showed that up to 12.5 mg/L C10 significantly inhibited SVCV replication in the epithelioma papulosum cyprini (EPC) cell line, with a maximum inhibitory rate of >97%. Furthermore, C10 significantly reduced cell death and relieved cellular morphological damage in SVCV-infected cells. Decreased mitochondrial membrane potential (ΔΨm) also suggested that C10 not only protected mitochondria, but also reduced apoptosis in SVCV-infected cells. For in vivo studies, intraperitoneal injection of C10 resulted in an anti-SVCV effect and substantially enhanced the survival rate of virus-infected zebrafish. Furthermore, C10 significantly enhanced antioxidant enzyme activities and decreased reactive oxygen species (ROS) to maintain antioxidant-oxidant balance within the host, thereby contributing to inhibition of SVCV replication. The up-regulation of six interferon (IFN)-related genes also demonstrated that C10 indirectly activated IFNs for the clearance of SVCV in zebrafish. This was beneficial for the continuous maintenance of antiviral effects because of the low viral loads in fish. Thus, C10 is suggested as a therapeutic agent with great potential against SVCV infection in aquaculture.

As one of the most serious pathogens in the freshwater aquatic environment, Saprolegnia can induce a high mortality rate during the fish egg incubation period. This study investigated the anti-Saprolegnia activity of a total of 108 plants on Saprolegnia parasitica in vitro and Dioscorea collettii was selected for further studies. By loading on an open silica gel column and eluting with petroleum ether-ethyl acetate-methanol, dioscin (C45H72O16) was isolated from D. collettii. Saprolegnia parasitica growth was inhibited significantly when dioscin concentration was more than 2.0 mg L(-1). When compared with formalin and hydrogen peroxide, dioscin showed a higher inhibitory effect. As potential inhibition mechanisms, dioscin could cause the S. parasitica mycelium morphologic damage, dense folds, or disheveled protuberances observed by field emission scanning electron microscopy and the influx of Propidium iodide. The structural changes in the treated mycelium were indicative of an efficient anti-Saprolegnia activity of dioscin. The oxidative stress results showed that dioscin also accumulated reactive oxygen species excessively and increased total antioxidant and superoxide dismutase activity. These situations could render S. parasitica more vulnerable to oxidative damage. Additionally, when dioscin concentration was less than 2.0 mg L(-1), the survival rate of embryos was more than 70%. Therefore, the use of dioscin could be a viable way of preventing and controlling saprolegniasis., (© FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)