Acute toxic effects of thiamethoxam on Chinese mitten crab Eriocheir sinensis.

The information about toxic effects of thiamethoxam on non-target aquatic organisms is still incomplete. The semi-static toxicity test method was used to investigate the acute toxic effects of thiamethoxam on Eriocheir sinensis. The results showed that the median lethal concentration (LC50) of thiamethoxam to E. sinensis at 96 h was 510 µg/L, and the safety concentration (SC) was 51 µg/L. After 96 h exposure to thiamethoxam, the survival rates of crabs at concentrations of 0, 151.11, 226.67, 340, and 510 µg/L were 100%, 76.19%, 64.29%, 61.91%, and 46.43%, respectively. A significant (P < 0.05) decrease of the number of hemocytes was observed in thiamethoxam groups. With the increase of thiamethoxam concentration, the phagocytic activity of hemocytes, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and the activities of protease, amylase, and lipase of crabs increased firstly and then decreased, and the above indexes reached the maximum in 151.11 µg/L thiamethoxam group. Collectively, a high concentration of thiamethoxam (510 µg/L) had a great effect on the gene expression of immune metabolism-related factors in hepatopancreas and gill of crabs. These findings indicated that thiamethoxam exposure had the ability to impair immune and metabolic systems and resulted in the reduction of survival rate of crabs.

Antibacterial Activity and Mechanism of the Gallnut Water Extract against Vibrio parahaemolyticus.

Vibrio parahaemolyticus is an important pathogen causing pandemic diseases in marine animals and brings about severe economic losses in aquaculture worldwide. The emergence of multi-drug-resistant V. parahaemolyticus and the prohibition of antibiotics both require the development of new therapeutic agents with alternative action. In this study, the effect of gallnut Galla chinensis water extract (GWE) on V. parahaemolyticus growth and virulence was investigated to determine the potential for its use in disease prevention and treatment in aquaculture. The minimum inhibitory concentration and minimum bactericidal concentration of GWE against V. parahaemolyticus were identified as 0.49 and 0.98 mg/mL, respectively. Membrane damage in V. parahaemolyticus was further verified through the increase of conductivity and leakage of nucleic acids and proteins. Moreover, GWE caused membrane invaginations and damage in V. parahaemolyticus as observed via scanning electron microscopy. After treatment with GWE, the biofilm formation and the activities of respiratory chain dehydrogenase, lactate dehydrogenase, and succinate dehydrogenase of V. parahaemolyticus were all significantly inhibited. These findings suggest that GWE has the potential to be developed as a supplemental agent to mitigate the infections caused by V. parahaemolyticus in aquaculture.

Effects of glycosaminoglycan from Urechis unicinctus on the P2Y1 receptor pathway and expression of related factors in rat platelets.

The aim of this study was to examine the effects of glycosaminoglycan (GAG) from Urechis unicinctus on the P2Y1 receptor pathway and expression of related factors in rat platelets. The concentration of calcium ion (Ca2+) in rat platelets was determined by double wavelength Fura-2 fluorescence spectrophotometry, and the concentrations of inositol trisphosphate (IP3) and glycoprotein IIb/IIIa (GPIIb/IIIa) in rat platelets were measured using the enzymatic immunoassay method. The phosphorylation levels of phospholipase C (PLC), phospholipase A2 (PLA2), protein kinase C (PKC), and p38 mitogen-activated protein kinase (p38MAPK) were also detected by Western blot. It was found that the GAG from U. unicinctus significantly reduced the Ca2+ and IP3 levels in rat platelets (p<0.05, p<0.01). Moreover, medium and high concentrations of GAG significantly reduced the concentration of the platelet membrane GPIIb/IIIa in rats (p<0.05, p<0.01). The phosphorylation levels of PLC, PLA)2), PKC and p38MAPK in rat platelets were also inhibited by GAG and P)2)Y)1) receptor blocker MRS2179 (p<0.05, p<0.01). However, the degree of inhibition of GAG was lower than that of MRS2179. The results laid a foundation for further utilization of the glycosaminoglycan.

Effects of Glycosaminoglycan from Urechis unicinctus on ADP-Induced Platelet Calcium and Membrane Glycoprotein Expressions in Rats.

BACKGROUND: Previous studies had shown that glycosaminoglycan (GAG) from Urechis unicinctus exerts an obvious antiplatelet aggregation effect. OBJECTIVE: This study aims to investigate the effects of GAG from Urechis unicinctus on ADP-induced platelet calcium and membrane glycoprotein expressions in rats. METHODS: Fura-2/AM fluorescence probe was used to measure intracytosolic free-calcium concentration ([Ca2+]i) of platelets and calculate platelet calcium influx and release concentrations. Flow cytometry was used to detect the expressions of platelet membrane glycoproteins GPIIb/IIIa (PAC-1) and P-selectin (CD62P) in rats. RESULTS: The results showed that the GAG from U. unicinctus significantly inhibited the release of platelet calcium (p < 0.01) and the expressions of platelet GPII b/IIIa and P-selectin (p < 0.01) induced by ADP in rats but had no significant effect on the influx of platelet calcium (p > 0.01). CONCLUSIONS: This study indicated that GAG may inhibit platelet activation and aggregation by reducing the release of Ca2+ and ADP-induced expression of platelet membrane glycoprotein in rats.

Effects of glycosaminoglycan from Mactra veneriformis on the protein C system and expression of relevant factors in human umbilical vein endothelial cells.

The aim of this study was to examine whether glycosaminoglycan (GAG) from Mactra veneriformis had an impact on the protein C (PC) system in rats and expression of relevant factors in human umbilical vein endothelial cells. Isotonic saline, heparin sodium (4 mg/kg), and GAG (1, 4, and 16 mg/kg) were administered to Wistar rats through caudal vein at the total volume of 0.5 ml for each injection, and the anticoagulant blood was prepared. The activities of PC and protein S, and the concentrations of activated protein C inhibitor (APCI) and thrombomodulin were detected according to the kit instructions. The expression levels of tissue factor, tissue factor pathway inhibitor and thrombomodulin genes in human umbilical vein endothelial cells were detected by the reverse transcription polymerase chain reaction method. GAG could significantly reduce the activity of PC (P < 0.05, P < 0.01) and slightly increase the concentration of APCI, and high concentration of GAG could significantly decrease the activity of protein S (P < 0.05) and significantly increase the concentration of thrombomodulin (P < 0.05). GAG could significantly downregulate the expression level of tissue factor gene (P < 0.05, P < 0.01) and significantly upregulate the expression levels of tissue factor pathway inhibitor and thrombomodulin genes (P < 0.05, P < 0.01). GAG showed the inhibitory effect on PC system in vivo. GAG might play an important role in the resistance to extrinsic coagulation pathway.

Complete mitochondrial genome of Acrossocheilus stenotaeniatus (Osteichthyes: Cyprinidae).

Acrossocheilus stenotaeniatus (Cypriniformes, Cyprinidae) is a barred cyprinid fish that inhabits the flowing freshwaters in China. The complete mitochondrial genome sequence of A. stenotaeniatus is 16,594 bp in length and comprises 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region. The base composition of the genome is 31.22% A, 24.70% T, 28.02% C, and 16.07% G, which shows considerable bias to A + T (55.91%). Results of this study provide important DNA molecular data for further phylogenetic analysis and resource management not only for congeneric species but also for higher taxa of Cyprinid fish.

Mitochondrial genome of Onychostoma macrolepis (Osteichthyes: Cyprinidae).

Onychostoma macrolepis, which belongs to the genus Onychostoma (Cypriniformes, Cyprinidae), is a benthopelagic fish that inhabits the flowing freshwaters in China. The complete mitochondrial genome sequence of O. macrolepis is 16,595 bp in length and comprises 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and 1 control region. The base composition of the genome is 31.29% A, 24.53% T, 27.97 % C, and 16.21% G, showing considerable bias toward an A + T preference as 55.82%. The results can provide a basic database for analyzing the phylogenetic relationship and conservation genetics in the genus Onychostoma.

Hypoglycemic effects of glycosaminoglycan from Urechis unicinctus in diabetic mice.

To further utilize glycosaminoglycan from Urechis unicinctus, the hypoglycemic effect and possible mechanism of glycosaminoglycan on diabetic mice were evaluated. Diabetes was induced in mice by intraperitoneal injections of streptozotocin for 3 consecutive days and fed with high-sugar and high-lipid fodder. After diabetes was confirmed, the hypoglycemic effect of glycosaminoglycan from U. unicinctus was investigated in the diabetic mice. Results demonstrated that glycosaminoglycan could significantly decrease blood glucose concentrations, HOMA-IR, AUG, and liver MDA content in diabetic mice. In addition, it significantly enhanced liver SOD and GSH-Px activity, as well as liver GCK activity and hepatic glycogen levels. Glycosaminoglycan from U. unicinctus exhibited efficacy against diabetes, suggesting its potential use as a natural intervention against diabetes.

The preliminary study on the antithrombotic mechanism of glycosaminoglycan from mactra veneriformis.

The effect of glycosaminoglycan from Mactra veneriformis on deep venous thrombosis of rats was observed, and the preliminary antithrombotic mechanism of glycosaminoglycan was explained. The results showed that when the glycosaminoglycan was injected intravenously into rats within the dose range of 0.0313-1 mg/kg, the antithrombotic effect increased as the dose increased. When the dose was increased to and exceeded 0.125 mg/kg, deep venous thrombosis caused by blood stagnation was inhibited significantly or extremely remarkably (P < 0.05, P < 0.01), while the intensity was similar to that of the tool drug heparin sodium at the same dose and weaker than that of heparin calcium of low molecular weight at three times' dose in clinics. Three doses (0.1, 0.4 and 1.6 mg/kg) of glycosaminoglycan were intravenously injected via mice tail, resulting in an extremely significant increase of activated partial thromboplastin time (APTT) and thrombin time (TT) (P < 0.01), no significant change of prothrombin time (PT) (P > 0.05), and a weaker anticoagulant effect than that of heparin sodium. In-vitro experiments demonstrated that except for the 2 µg/ml of glycosaminoglycan (P > 0.05), other final concentration groups significantly or extremely significantly prolonged the APPT, TT and PT of rabbits (P < 0.05, P < 0.01), but with a slightly weaker anticoagulant effect than that of heparin sodium; The antiplatelet aggregation experiments using big-eared rabbits manifested that glycosaminoglycan markedly decreased the maximum aggregation percentage of rabbits blood platelet (P < 0.01), which indicated that it had good antiplatelet aggregation effect, but the intensity was weaker than the positive control drug, Ozagrel sodium.