•Exogenous chitosan (CTS) reduced detrimental effect of Cd on rape plant growth.•Foliar application of CTS under Cd tress decreased shoot Cd2+ concentration.•CTS enhanced photosynthesis and antioxidant enzymes activities.Chitosan (CTS) induces plant tolerance against several abiotic stresses, including salinity and drought exposure. However, the role of CTS in cadmium (Cd)-induced stress amelioration is largely unknown. In the present study, a hydroponic pot experiment was conducted to study the roles of CTS with different molecular weight (Mw) (10 kDa，5 kDa and 1 kDa) in alleviating Cd toxicity in edible rape (Brassica rapa L .). The results showed that Cd stress significantly decreased plant growth, leaf chlorophyll contents and increased the malondialdehyde (MDA) level in rape leaves. Foliar application of CTS promoted the plant growth and leaf chlorophyll contents, and decreased the malondialdehyde (MDA) level in edible rape leaves under Cd stress. The alleviation effect of CTS on toxicity was depended on its Mw and CTS with Mw of 1 kDa showed the best activity. Spraying 1 kDa CTS onto the leaves of edible rape under Cd-toxicity could decrease shoot Cd2+ concentration and improve photosynthetic characteristics of edible rape. Moreover, 1 kDa CTS also significantly enhanced non-enzymatic antioxidants (ascorbic acid) and enzyme activities (superoxide dismutase, catalase and guaiacol peroxidase) under Cd stress. Based on these findings, it can be concluded that application of exogenous CTS could be an effective approach to alleviate the harmful effects of Cd stress and could be explored in an agricultural production system.

•Jellyfish N. nomurai and C. nozakii nematocyst venom exhibited significant enzymatic properties.•Jellyfish venom metalloproteinase activity and PLA2 activity varied depending on the physicochemical conditions.•NnNV metalloproteinases kinetically degraded azocasein with the Vmax value of 11.4 ± 1.2 U/mg/min.•NnNV PLA2s exhibited slightly higher catalytic activity on NOBA than that of CnNV with a kcat value of 7.5 × 10−3 min−1.Jellyfish envenomations are emerging as an important public health concern occurred worldwide. In China, the situation is getting worse with numerous people stung by jellyfish Nemopilema nomurai (N. nomurai) and Cyanea nozakii (C. nozakii) in the summer. However, the proteinaceous mixtures in nematocysts responsible for the symptoms of jellyfish stings were scarcely characterized and understood in view of enzymatic constituents and toxicity. In the present study, enzymatic properties of jellyfish N. nomurai and C. nozakii nematocyst venom were analyzed biochemically and kinetically. The current data revealed that N. nomurai and C. nozakii nematocyst venom exhibited various enzymatic activities, of which metalloproteinases activity and PLA2s-like activity were predominant. Moreover, the catalytic activities of metalloproteinases and PLA2s-like were dependent on different physiochemical conditions such as temperature, pH and divalent ions. Kinetic profiling revealed their catalytic behaviors fitted the Michaelis-Menten equation under specific conditions. Findings suggested jellyfish nematocyst venom possessed diverse enzymatic constituents, which may underlie the extensively characterized bioactivities of jellyfish venom and human envenomations. Hence, our study will contribute to understanding the enzymatic constituents and toxicity of jellyfish nematocyst venom and may afford potential therapeutic targets for developing drugs for jellyfish stings.

Seven chitooligomers (COSs) with determined degrees of polymerization (DPs) (chitotetraose to chitooctaose, DP 8–10, DP 10–12) and a heterogeneous COS with various DPs were first applied to explore the relationship between the DP of COSs and their effect on the growth of wheat seedlings under salt stress. The results showed that COS could promote the growth of wheat seedlings under salt stress. Moreover, chitohexaose, chitoheptaose, and chitooctaose exhibited stronger activity compared with other COS samples, which suggested that their activity had a close relationship with the DP. After 10 days of treatment with chitohexaose, chitoheptaose, and chitooctaose, the photosynthetic parameters were obviously improved. The soluble sugar and proline contents were improved by 26.7–53.3 and 43.6–70.2%, respectively, whereas the concentration of malondialdehyde (MDA) was reduced by 36.8–49.6%. In addition, the antioxidant enzyme activities were clearly activated. At the molecular level, the results revealed that they could obviously induce the expression of Na+/H+ antiporter genes.Keywords: antioxidant enzyme activities; chitooligomers; degrees of polymerization; gene expression; photosynthesis; salt stress;

•COS alleviated the toxic effect of Cd and improved the morpho-physiology of plants.•COS significantly decreased the Cd concentrations both in shoots and roots of plants.•Foliar application with COS under Cd tress enhanced antioxidant enzymes activities.•COS modified Cd subcellular distribution and enhanced Cd fixation to vacuoles.Cadmium (Cd) is one of the most toxic heavy metals, which is readily taken up by plant roots and has deleterious effects on crop yield and quality. The study investigated the potential cross-protection roles of chitooligosaccharide (COS) in alleviating Cd toxicity in edible rape (Brassica rapa L.) under greenhouse conditions. The results demonstrated that spraying COS onto the leaves of edible rape could promote the plant growth and leaf chlorophyll contents, decrease the malondialdehyde (MDA) level in leaves as well as the Cd2+ concentration in shoots and roots of edible rape under Cd stress. Moreover, exogenous COS could obviously enhance the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) in edible rape leaves under Cd-toxicity. The alleviation effect of COS on Cd stress was concentration-dependent and COS of 50–100 mg L−1 showed the best activity. Subcellular distribution experiments further revealed that COS of 50 mg L−1 decreased the proportion of Cd in the organelle fraction of leaves by 40.1% while increased the proportion of Cd in the soluble fraction by 13.2%. These results indicated that COS had a potential to enhance plant resistance to Cd through promoting antioxidant enzyme activities and altering Cd subcellular distribution.

Fluorine poisoning affects human health all over the world and an urgent task is to develop alleviative medicine to recover or ameliorate the damages to the body. Here we studied the effects of gamma-aminobutyric acid (GABA), a liver protector reported previously, on fluoride-induced damage in the mouse liver. Through microscope imaging of the liver tissue, TUNEL immunostaining, real-time RT-PCR, enzyme immunoassay and colorimetric method, we found that GABA supplementation prevented the metabolic toxicity caused by fluoride treatment in mice. This detoxification was reflected by the reduced oxidative stress and apoptosis, enhanced neuron protection and liver function. Collectively, this study provided evidence of the beneficial effects of GABA supplement on liver damage, implicating its therapeutic potential in fluorosis.

•174 potential toxins were identified using proteomics and transcriptomics approach.•27 proteins are homology to the toxins from venomous animals.•Metalloproteinases PLA2s and serine protease inhibitors are predominant component.•Venom composition of C. nozakii and other three jellyfish shows large differences.Jellyfish sting has become a worldwide issue of critical concern to human health and safety in coastal areas in recent decades. Cyanea nozakii is one of the dominant blooming species and dangerous stingers in China. However, it remains unclear how many and what types of toxins are present in the venom. So, we used a combined transcriptomics and proteomics approach to investigate the venom composition of jellyfish C. nozakii. In total 4,608,524 Illumina valid reads were obtained to de novo assemble to 40,434 unigenes in the transcriptomics analysis. And, a total of 311,635 MS/MS spectra with 12,247 unique MS/MS spectra were generated to 1556 homologous proteins in the proteomics analysis. 174 potential toxin proteins were identified, with 27 proteins homology to the toxins from venomous animals, including phospholipase A2, zinc metalloproteinase-disintegrin agkistin, serine protease inhibitor, plancitoxin-1, alpha-latrocrustotoxin-Lt1a, etc. This study described the transcriptomics and venom proteomics of jellyfish C. nozakii for the first time. Our findings provide a comprehensive understanding of the venom composition of C. nozakii. Furthermore, the results may also be very helpful for the discovery of novel bioactive proteins, as well as the development of effective treatments for jellyfish sting in the future.Biological significanceJellyfish Cyanea nozakii is one of the most dangerous stingers in the coast of china. Hundreds of thousands of people would be stung every year and victims suffered a severe pain, itch, swelling, inflammation, wheal and even more serious consequence. However, it remains unclear how many and what types of toxins are present as well as the relationship between the clinical symptoms and toxins. Our combined transcriptomics and proteomics findings can provide a comprehensive understanding of the venom composition of C. nozakii and will also be helpful for the development of effective treatments for jellyfish sting in the future.

•Both separation and synthesis methods for single COS preparation are summarized.•An overview of techniques to analyze well-defined COS is provided.•Recent progress in diverse bioactivities of COS of defined size is presented.Chitooligosaccharides (COS), as a source of potential bioactive material, has been reported to possess diverse bioactivities. These bioactivities of COS are often tested using relatively poorly characterized oligomer mixtures during past few decades, resulting in difficult identification of COS molecules responsible for biological effects. Therefore, a new interest has recently been emerged on highly purified COS of defined size. Several technological approaches have been used to produce single COS and new improvements were introduced to their characterization in order to understand the unrevealed structure-function relationship. Here we provide an overview of techniques that were used to prepare and analyze reasonably well-defined COS fractions. Based on the latest reports, several applications of single COS for plants and animals, are also presented, including antitumor, immunostimulatory, antioxidant, antimicrobial, elicitors of plant defence and neural activity.

•We prepared nine single or narrow degrees of polymerization chitooligomers (COSs).•We investigated the size effects of COSs on growth of wheat seedlings.•COSs with DP > 3 had a significant promotion effect on the growth and photosynthesis.•Chitoheptaose exhibited the optimal activity compared with other COS samples.In this study, nine chitooligomers (COSs) including seven single COSs (chitobiose to chitooctaose) and two COS fractions with narrow degrees of polymerization (DPs) (DP8–10, DP10–12) were prepared and applied to wheat seedlings to investigate the size effects of COSs on the growth and photosynthesis parameters of wheat seedlings. The results showed that the activities of COS were closely related to their DPs, and DP > 3 was necessary to insure a significant promotion effect on the growth and photosynthesis. Moreover, chitoheptaose exhibited the optimal activity compared with other COS samples. After 7 days of chitoheptaose treatment, the growth parameters of wheat seedlings could be significantly improved and the contents of soluble sugar, soluble protein and chlorophyll were increased by 59.4%, 22.0% and 20.3%, respectively. In addition, chitoheptaose could significantly enhance the net photosynthetic rate of wheat seedlings with the values of Fv/Fo, qP and Rfd increased by 11.0%, 18.6% and 14.7%, respectively, while NPQ was decreased obviously, which might resulted in the promotion of light utilization efficiency and the growth of wheat seedlings.

In this study, sulfated chitooligosaccharide (SCOS) was applied to wheat seedlings to investigate its effect on the plants’ defense response under salt stress. The antioxidant enzyme activities, chlorophyll contents, and fluorescence characters of wheat seedlings were determined at a certain time. The results showed that treatment with exogenous SCOS could decrease the content of malondialdehyde, increase the chlorophyll contents, and modulate fluorescence characters in wheat seedlings under salt stress. In addition, SCOS was able to regulate the activities of antioxidant enzymes containing superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase. Similarly, the mRNA expression levels of several antioxidant enzymes were efficiently modulated by SCOS. The results indicated that SCOS could alleviate the damage of salt stress by adjusting the antioxidant enzyme activities of plant. The effect of SCOS on the photochemical efficiency of wheat seedlings was associated with its enhanced capacity for antioxidant enzymes, which prevented structure degradation of the photosynthetic apparatus under NaCl stress. Furthermore, the effective activities of alleviating salt stress indicated the activities of SCOS were closely related with the sulfate group.

Three novel 6-N-substituted chitosan derivatives were designed and synthesised and characterized by FTIR and NMR. The degree of substitution was calculated by elemental analysis results. The antimicrobial activities of the target compounds were evaluated by twofold serial broth dilution method and poisoned food technique. The antifungal activities of 6-aminoethylamino-6-deoxy chitosan (3), 6-butylamino-6-deoxy chitosan (4) and 6-pyridyl-6-deoxy chitosan (5) were significantly increased against Rhizoctonia cerealis, Fusarium oxysporum and Botrytis cinerea, and the inhibition rate ranged from 22.48% to 63.56% at the concentration of 0.2 mg/mL. The compound 3 had better antibacterial activities than chitosan, and the minimum inhibition concentration of which ranged between 6.25 and 25 mg/L against gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis and Bacillus anthracis) and gram-negative bacteria (Escherichia coli, Salmonella typhi). The antibacterial activities of 6-N-substituted chitosan tended to increase with the increase of the number of –NH2 group.

•Chitooligosaccharides (COSs) with different degrees of acetylation (DAs) were firstly applied to investigate the effect on salt-tolerance of plant.•COS with DA 50% was more effective on alleviating salt stress than those with other DAs.•Treatment with COS on wheat may modulate intracellular ion concentrations and enhance the antioxidant enzymes activities.In this study, chitooligosaccharides (COSs) with varying degrees of acetylation (DAs) were applied to wheat seedlings in order to investigate their effect on the plants’ defence response under salt stress. The results showed that treatment with exogenous COSs that had different DAs could promote the growth of plants, decrease the concentration of malondialdehyde (MDA), improve the photosynthetic efficiency and enhance the activities of antioxidant enzymes. The mRNA expression level examination of several salt stress response genes suggested that COS could protect plants from the damage of salt stress by adjusting intracellular ion concentration and enhancing the activities of antioxidant enzymes. Furthermore, COS with DA 50% was the most effective in alleviating salt stress to wheat seedlings, which indicated that the activity of COS was closely related with its DAs.

•Adsorption property of inulin onto activated charcoal was revealed.•Both kinetic and thermodynamic analyses for the adsorption studies were processed.•Desorption can effectively be attained using 50% ethanol.•Activated charcoal can be reused without significant losses in adsorption capacity.This study describes liquid phase adsorption characteristics of inulin-type fructan onto activated charcoal. Batch mode experiments were conducted to study the effects of pH, contact time, temperature and initial concentration of inulin. Nearly neutral solution (pH 6–8) was favorable to the adsorption and the equilibrium was attained after 40 min with the maximum adsorption Qmax 0.182 g/g (adsorbate/adsorbent) at 298 K. The experimental data analysis indicated that the adsorption process fitted well with the pseudo-second-order kinetic model (R2 = 1) and Langmuir isotherms model (R2 > 0.99). Thermodynamic parameters revealed that the adsorption process was spontaneous and exothermic with a physical nature. Inulin desorption could reach 95.9% using 50% ethanol solution and activated charcoal could be reused without significant losses in adsorption capacity. These results are of practical significance for the application of activated charcoal in the production and purification of inulin-type fructan.

•Venomics analysis of the jellyfish S. meleagris.•Venom gland transcriptomics analysis of the jellyfish S. meleagris.•A total of 218 toxins in the venom might be associated with sting.Jellyfish Stomolophus meleagris is a very dangerous animal because of its strong toxicity. However, the composition of the venom is still unclear. Both proteomics and transcriptomics approaches were applied in present study to investigate the major components and their possible relationships to the sting. The proteomics of the venom from S. meleagris was conducted by tryptic digestion of the crude venom followed by RP-HPLC separation and MS/MS analysis of the tryptic peptides. The venom gland transcriptome was analyzed using a high-throughput Illumina sequencing platform HiSeq™ 2000 with de novo assembly. A total of 218 toxins were identified including C-type lectin, phospholipase A2 (PLA2), potassium channel inhibitor, protease inhibitor, metalloprotease, hemolysin and other toxins, most of which should be responsible for the sting. Among them, serine protease inhibitor, PLA2, potassium channel inhibitor and metalloprotease are predominant, representing 28.44%, 21.56%, 16.06% and 15.14% of the identified venom proteins, respectively. Overall, our combined proteomics and transcriptomics approach provides a systematic overview of the toxins in the venom of jellyfish S. meleagris and it will be significant to understand the mechanism of the sting.Biological significanceJellyfish Stomolophus meleagris is a very dangerous animal because of its strong toxicity. It often bloomed in the coast of China in recent years and caused thousands of people stung and even deaths every year. However, the components which caused sting are still unknown yet. In addition, no study about the venomics of jellyfish S. meleagris has been reported. In the present study, both proteomics and transcriptomics approaches were applied to investigate the major components related to the sting. The result showed that major component included C-type lectin, phospholipase A2, potassium channel inhibitor, protease inhibitor, metalloprotease, hemolysin and other toxins, which should be responsible for the effect of sting. This is the first research about the venomics of jellyfish S. meleagris. It will be significant to understand the mechanism of the biological effects and helpful to develop ways to deal with the sting.

Hollow nestlike α-Fe2O3 spheres were successfully synthesized via a facile template-free, glycerol-mediated hydrothermal process employing microwave heating. The product was characterized using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption measurements. The as-prepared product was found to consist of hierarchically nanostructured spheres assembled of nanorod subunits. The effect of the relative amount of glycerol in the reaction system on the composition and morphology of the products was systematically studied, and a possible formation mechanism of the hollow nestlike spheres was proposed. Because of their large surface area and unique mesoporous structure, we investigated the potential application of the hollow α-Fe2O3 spheres in water treatment. With maximum removal capacities of 75.3, 58.5, and 160 mg g–1 for As(V), Cr(VI), and Congo red, respectively, these novel nanostructures have the potential to be used as low-cost and efficient adsorbent materials for the removal of toxic metal ions and organic pollutants from water.Keywords: adsorption; Congo red; heavy-metal ions; hollow nanostructures; water treatment; α-Fe2O3;

The preparation of chitooligosaccharides with single degree of polymerization and well-defined degree of acetylation is of significance to identify the components possessing strong biofunction. This study focuses on the preparation of two partially acetylated chitotrioses (N-acetylchitotriose and N,N′-diacetylchitotriose), involving a two-step process: (i) partially N-acetylation of chitotriose and (ii) separation of different acetylated chitotrioses. The chitotriose was N-acetylated and characterized with FT-IR and ESI-MS. N-acetylchitotriose and N,N′-diacetylchitotriose were separated from the acetylated chitotriose mixture by CM Sepharose Fast Flow. Subsequently, the antioxidant activities of two partially acetylated chitotrioses and original chitotriose were investigated, including hydroxyl radical and superoxide radical scavenging activity. The results showed that the activities of the three oligomers were in a dose-dependence manner and related to their degree of acetylation. The N,N′-diacetylchitotriose with high degree of acetylation exhibited the highest antioxidant activity.Highlights► An N-acetylated chitotriose mixture is prepared. ► N-acetylchitotriose (D2A) and N,N′-diacetylchitotriose (DA2) were separated. ► The main isomers of D2A and DA2 were DDA and ADA, respectively. ► N-acetylation enhanced the antioxidant activity of chitotriose.

In this study, ammonium dithiocarbamate chitosan (ADTCCS) and triethylene diamine dithiocarbamate chitosan (TEDADTCCS) derivatives were obtained respectively by mixing chitosan with carbon disulfide and ammonia (triethylenediamine). Their structures were confirmed by FT-IR, 1H NMR, XRD, DSC, SEM, and elemental analysis. Antifungal properties of them against the plant pathogenic fungi Fusarium oxysporum and Alternaria porri were investigated at concentrations ranged from 31.25 to 500 mg/L. The dithiocarbamate chitosan derivatives had enhanced antifungal activity compared with chitosan. Particularly, they showed obvious inhibitory effect on Fusarium oxysporum. At 500 mg/L, TEDADTCCS inhibited growth of F. oxysporum at 60.4%, stronger than polyoxin and triadimefon whose antifungal indexes were found to be 25.3% and 37.7%. The chitosan derivatives described here deserve further study for use in crop protection.Highlights► Two dithiocarbamate chitosan derivatives were obtained. ► The derivatives had enhanced antifungal activity compared with chitosan. ► Both of the derivatives had a better activity against F. oxysporum than polyoxin.

Three novel thiosemicarbazone chitosan derivatives were obtained via condensation reaction of thiosemicarbazide chitosan with phenylaldehyde, o-hydroxyphenylaldehyde, and p-methoxyphenylaldehyde, respectively. Antifungal activity against the common crop-threatening pathogenic fungi Stemphylium solani weber (S. solani), Rhizoctonia solani Kühn (R. solani), Alternaria solani (A. solani), and Phomopsis asparagi (Sacc.) (P. asparagi) was tested in vitro at 0.05, 0.1, and 0.5 mg/mL. The derivatives had broad-spectrum antifungal activity that was greatly enhanced in comparison with chitosan. In fact, the highest antifungal index reached 100%. At 0.05 mg/mL, the o-hydroxyphenylaldehyde thiosemicarbazone chitosan inhibited growth of R. solani at 52.6%, and was stronger than polyoxin whose antifungal index was found to be 31.5%. The chitosan derivatives described here lend themselves to future applicative studies in agriculture.Highlights► Three novel thiosemicarbazone chitosan derivatives were obtained via condensation reaction of thiosemicarbazide chitosan with phenylaldehyde, o-hydroxyphenylaldehyde, and p-methoxyphenylaldehyde, respectively. ► The derivatives had broad-spectrum antifungal activity that was greatly enhanced in comparison with chitosan. ► Antifungal activity of o-HPHTCNCS against Stemphylium solani and Rhizoctonia solani was comparable to that of polyoxin. ► At 0.05 mg/mL, the o-hydroxyphenylaldehyde thiosemicarbazone chitosan inhibited growth of R. solani at 52.6%, and was stronger than polyoxin whose antifungal index was found to be 31.5%.

Chitooligomers (COS) with degree of polymerization (DP) ranging from 2 to 12 was prepared by acid hydrolysis of chitosan and five fractions were separated from the prepared COS by CM Sephadex C-25 column. The fractions were desalted by activated charcoal extraction. The components of each fraction were analyzed by TLC, HPLC and MALDI-TOFMS. Five fractions mainly contained trimer (95.7%), tetramer and pentamer (90.9%), pentamer (85.6%), hexamer (89.5%) and heptamer to decamer (94.7%), respectively. The antioxidant activities of each fraction and COS mixture were investigated, including hydroxyl and superoxide radical scavenging activity and reducing power. The activities of the six COSs were in a dose-dependence manner and related to their DP. The COS with low DP showed better effect of scavenging hydroxyl radical and reducing power than that with high DP. In contrast, the superoxide radical scavenging activity of all the tested COSs increased with DP increasing.Highlights► We separate five chitooligomers with different degree of polymerization (DP). ► DPs of five chitooligomers are 3, 4–5, 5, 6, and 7–10, respectively. ► Activated charcoal extraction was developed to desalt chitooligomers. ► The relationship of antioxidant activity and DP of chitooligomers was revealed.

•A new β-chitosan was prepared with high molecular weight and low acetylation degree.•Different molecular weight β-chitosan was obtained by microwave-assisted method.•Degraded β-chitosan has better antiviral activity than degraded α-chitosan.•β-Chitosan with 3–6 kDa molecular weight has best antiviral activity.Beta-chitosan has a parallel structure, which differs from alpha-chitosan's antiparallel structure while producing different properties and difficulties. In this paper, we prepared the beta-chitosan through acid and alkali methods and the resultant material was characterized by elemental analysis, FT-IR, HPLC, XRD, NMR and AFS. To increase the solubility and biological activity of the beta-chitosan, we degraded it through microwave-assisted process. After characterization, we determined that the chitosan had not changed its configuration during the reaction with H2O2 under microwave irradiation. The inhibitory activity of the degraded chitosan for Newcastle disease was revealed by a hemagglutination test and RT-PCR. The yield of the beta-chitosan was approximately 30%, and its molecular weight can be degraded to 1000 to 10,000 g/mol. Moreover, the degraded β-chitosan has higher antiviral activity, reducing the hemagglutination titre to zero, compared with alpha-chitosan. Therefore, beta-chitosan has good development prospects during the development of veterinary drugs for Newcastle disease.

Waste shells create several serious problems, however, only parts of them are being utilized now. Therefore, the ideal solution would be to convert the waste shells into a product that is both environmentally beneficial and economically viable. Scallop and oyster shells were exposed to heat treatment at 1050 °C. SEM and XRD analysis results showed that the resultant powder turned completely into CaO after the treatment. The antifungal activities of non-treated and heat-treated scallop and oyster shell powder slurry were investigated. Non- treated oyster shell powder exhibited a significant antifungal activity at 25,000 ppm. Its antifungal activities against Physalospora piricola Nose (P. piricola) and Rhizoctonia solani Kühn (R. solany) were even up to 100%. Moreover, increasing culture time did not alter the antifungal activities. Heat-treated scallop and oyster shell powder exhibited obvious antifungal activity at 500 ppm, at which concentration 100% inhibition of R. solany was observed. The possible antifungal mechanism of the oyster shell and its heat-treated counterpart was studied using R. solani Kuhn as model. The results illustrated that oyster shell is able to affect the membrane permeability of the fungus. The above-mentioned results showed that it is possible for oyster shell to be an agriculture fungicide.

•A novel kind of C-coordinated O-carboxymethyl chitosan Cu(II) complexes was prepared.•The structure were analyzed not only with the traditional analysis methods, but also with density functional theory (DFT).•Combined with the structure and antibacterial activities of the copper complexes, the Structure-activity relationship was discussed.A novel type of O-carboxymethyl chitosan Schiff bases (O-CSPX) was synthesized via a condensation reaction. After the coordination reaction of cupric ions, Cu(II) complexes (O-CSPX-Cu) were achieved. The theoretical structure of O-CSPX-Cu calculated by Gaussian 09 reveals that the copper ions underwent dsp2 hybridization, coordinated by the carbon atom in the p-π conjugate group and the oxygen atoms in the acetate ion. Then, the structures were confirmed by FT-IR, 1H NMR, CP-MAS 13C NMR, elemental analysis, DSC and XRD. The antifungal properties of O-CSPX-Cu against Phytophthora capsici (P. capsici), Gibberella zeae (G. zeae) and Glomerella cingulata (G. cingulata) were evaluated at concentrations ranging from 0.05 mg/mL to 0.20 mg/mL. The experiments indicated that the derivatives have significantly enhanced antifungal activity after copper ion complexation compared with the original chitosan. Moreover, it was shown that 0.20 mg/mL of O-CSP3-Cu and O-CSP4-Cu can 100% inhibit the growth of P. capsici. The experimental results reveal that the antifungal efficiency is related to the space steric hindrance on the benzene ring, which may provide a novel direction for the development of copper fungicides.

•Acute toxicological and pathological methods were used for the toxicity analysis.•The LD50 of the venom from jellyfish Stomolophus meleagris was about 2.92 μg/g body weight.•The venom caused renal glomerular swelling, vesicle stricture and tubules dilatation.•The venom caused liver blood sinusoid dilatation and malignant pleural effusion.•The venom also showed severe hematotoxicity and neurotoxicity.Jellyfish Stomolophus meleagris, a synonym of Nemopilema nomurai, which has often bloomed in the China Sea in recent years, is becoming an increasing threat to human health and life as a result of its strong toxicity. Each year, hundreds of thousands of people were stung, especially in the high season, and the victims suffered itch, edema, myalgia, dyspnea, hypotension, shock and even death. Here, we present the in-depth analysis of the in vivo toxicity of the venom from the jellyfish S. meleagris by using both an acute toxicological approach and pathological analyses. The venom showed an LD50 of approximately 2.92 μg/g body weight in mice following an intravenous injection and caused renal glomerular swelling, renal vesicle stricture, renal tubules dilatation, hepatic blood sinusoid dilatation, pulmonary edema and malignant pleural effusion. The pathological sections analysis showed that the kidney and liver were significantly damaged, but the heart, spleen and stomach had no observed changes. Additionally, the hemanalysis showed an increase of white blood cells (WBC), middle cells (Mid), alanine aminotransferase (ALT), blood urine nitrogen (BUN) and uric acid (UA) in the blood. Moreover, the mice also displayed convulsions, mouth bleeding, piloerection, dyspnea and death after the injection of the venom. In conclusion, this venom has a strong toxicity to the kidney of the mice and the acute renal failure might be one of the most important factors for the death after a severe sting. Hopefully, the present study will provide a significant reference for the treatment of stings by the jellyfish S. meleagris in the future.