Polystyrene microplastics enhanced copper-induced acute immunotoxicity in red swamp crayfish (Procambarus clarkii).

Microplastic pollution has attracted a lot of attention in recent years. Not only can it be ingested by animals, but it can easily become a carrier of other pollutants, forming a composite pollutant with potentially toxic effects on organisms. We investigated the effect of Cu on the accumulation of polystyrene microplastics (PS) in the gills of Procambarus clarkii and whether PS exacerbated the immune toxicity of Cu to P. clarkii were exposed to Cu, PS and PS+Cu for 48 h, the accumulation of PS in gill and hepatopancreas immune and antioxidant indices were analyzed. The objective was to investigate the toxic effects of Ps and Cu compound pollutants on P. clarkii and whether the accumulated pollutants would cause food safety problems. The results showed that microplastic particles adhered to each other and aggregated in the PS+Cu group, and the number of microplastic particles in gill in the PS+Cu group was significantly lower than that in the PS group. Compared with the other two treatment groups, SOD, CAT, GPx activities and MDA content increased significantly in the PS+Cu group and were relatively delayed. At 12 h, 24 h, 36 h and 48 h, the SOD mRNA expression levels in the PS+Cu group were all significantly lower than those in the Cu group (P < 0.05). At 24 h and 48 h, CAT mRNA expression in the PS+Cu group was significantly higher than that in the Cu group (P < 0.05). Crustin 4 mRNA expressions in the PS+Cu group was significantly higher than that in the Cu group at 12 h and 36 h (P < 0.05). The results demonstrate that the PS and Cu compound reduced the accumulation of microplastic particles in the gill. PS particles delayed Cu entry into P. clarkii for a short time (12 h) and reduced the toxic effect, but with the increase of exposure time (24 h and 48 h), the toxic effect of PS and Cu complexes on P. clarkii increases, and the large accumulation of PS and Cu complexes may cause food safety problems.

Combined impacts of microplastics and cadmium on the liver function, immune response, and intestinal microbiota of crucian carp (Carassius carassius).

Microplastics (MPs) and the heavy metal cadmium (Cd) have attracted global attention for their toxicological interactions in aquatic organisms. The purpose of this investigation was evaluating the effect of MPs (1 mg L-1) and Cd (5 mg L-1) on the liver function, immune response of crucian carp (Carassius carassius) after 96 h exposure, and intestinal microbiota after 21 days, respectively. Co-exposure to MPs and Cd significantly enhanced MP accumulation in the liver of the crucian carp compared to the accumulation with exposure to MPs alone. Co-exposure to MPs and Cd triggered notable histopathological alterations accompanied by increased hepatic cell necrosis and inflammation, and was associated with higher aspartate aminotransferase and alanine aminotransferase levels, lower superoxide dismutase and catalase activity levels, but higher malondialdehyde content and total antioxidant capacity in the liver. Moreover, the combined treatment of MPs and Cd led to the up-regulated transcription of genes related to immune response, such as interleukin 8 (il-8), il-10, il-1ß, tumor necrosis factor-α, and heat shock protein 70, both in the liver and spleen. Co-exposure to MPs and Cd reduced the variety and abundance of the intestinal microbiota in the crucian carp. Our research indicates that the combined exposure to MPs and Cd may exert synergistic toxic effects on crucian carp, which could impede the sustainable growth of the aquaculture industry and pose potential risks to food safety.

The effect of nitrite and sulfide on the antioxidant capacity and microbial composition of the intestines of red swamp crayfish, Procambarus clarkii.

Nitrite and sulfide are harmful pollutants in water ecosystems that negatively influence the survival and growth of crayfish. It is currently known that the intestine of crustaceans acts as a significant immune organ, serving as the front line of defense against diseases. In this study, we investigated how the oxidative damage parameters, antioxidant status and microbial composition of the intestine of Procambarus clarkii were influenced under acute nitrite (60 mg/L) and sulfide (18 mg/L) stress for 72 h. Compared with the control, after exposure to nitrite and sulfide stress, the production of reactive oxygen species, and the lipid peroxide and malondialdehyde contents increased in the intestines and were significantly higher after 72 h of exposure. The superoxide dismutase, catalase and glutathione peroxidase activities increased to maximum levels at 6, 24 and 12 h, respectively. These activities then decreased gradually and were significantly lower than those of the control after 48 or 72 h of exposure. In the crayfish exposed to stress, the expression of antioxidant genes including heat shock protein 70, ferritin and metallothionein increased to their maximum values at 12, 48 and 12 h, respectively. The expression levels then decreased gradually, and after 72 h, were lower than, or lacked significant differences with, the expression levels in the control. Additionally, nitrite and sulfide exposure restructured the intestinal microbial community of P. clarkii. This led to decreases in the abundance of some genera such as Citrobacter. However, the abundance of other genera, such as Shewanella and Acinetobacter, increased. Therefore, the health of P. clarkii was seriously impaired when exposed to nitrite and sulfide stress.

Effects of Hypoxia Stress on Survival, Antioxidant and Anaerobic Metabolic Enzymes, and Related Gene Expression of Red Swamp Crayfish Procambarus clarkii.

The red swamp crayfish Procambarus clarkii is the most reared shrimp in China, but it is often affected by hypoxia stress in the process of seedling culture and adult crayfish culture. The oxygen consumption rate and asphyxiation point of juvenile crayfish (1.17 ± 0.03 g) and subadult crayfish (11.68 ± 0.11 g) at different temperatures (20, 22, 24, 26, and 28 °C) were studied. The survival, glycolysis, and expression of antioxidant genes were compared under 24 h acute hypoxia stress (1, 2, and 3 mg/L) and normal dissolved oxygen (7.5 mg/L). The results showed that the oxygen consumption rate and asphyxiation point of juvenile and subadult crayfish increased with increasing temperatures (20-28 °C). At the same temperature, the oxygen consumption rate and asphyxiation point of juvenile crayfish were significantly higher than those of subadult crayfish (p < 0.05). Within 24 h, the three hypoxia stress environments did not lead to the death of crayfish, indicating that P. clarkii has a strong ability to adapt to hypoxia. Hypoxia stress significantly affected the activities of antioxidant and anaerobic metabolic enzymes and gene expression in juvenile and subadult crayfish. The activities of the superoxide dismutase (SOD), catalase (CAT), and lactate dehydrogenase (LDH) and the content of lactic acid (LD) in the hepatopancreas of juvenile and subadult crayfish in the hypoxia stress groups increased significantly. The expression levels of SOD mRNA, CAT mRNA, Hsp70 mRNA, and crustin 4 mRNA in the hepatopancreas of juvenile and subadult crayfish in the hypoxia stress groups were significantly higher than those in the control group (p < 0.05), and the higher the degree of hypoxia stress, the higher the expression of each gene. The results showed that the antioxidant system of juvenile crayfish was more sensitive to hypoxia environments, and hypoxia stress resulted in increased stress levels in juvenile crayfish and subadult crayfish.

Exploring the poverty-reduction benefits of agricultural machinery socialization services in China: Implications for the sustainable development of farmers.

Sustainable development is crucial for alleviating poverty among farmers. In this study, we examined the impact, and the mechanism underlying this impact, of the adoption of agricultural machinery services by farmers on their relative poverty from a multidimensional poverty perspective by employing the logit and ordered logit models and the Karlson-Holm-Breen (KHB) method. These results indicate that adopting agricultural machinery services can significantly reduce the probability of relative poverty among farmers, thereby expediting the sustainability of rural development. However, this poverty-reduction effect varies based on age and sex. The adoption of agricultural machinery services mainly reduces poverty by increasing farmers' human capital. Training in employment skills and non-agricultural work experience are the main transmission mechanisms. Therefore, the socialization of agricultural machinery services can be used as an effective policy tool to reduce relative poverty in developing countries, promote sustained improvements in farmers' incomes, and achieve sustainability in rural development.

Safety assessment of subchronic feeding of insect-resistant and herbicide-resistant transgenic soybeans to juvenile channel catfish (Ictalurus punctatus).

Transgenic soybean is one of the most planted crops for human food and animal feed. The channel catfish (Ictalurus punctatus) is an important aquatic organism cultured worldwide. In this study, the effect of six different soybean diets containing: two transgenic soybeans expressing different types of cp4-epsps, Vip3Aa and pat genes (DBN9004 and DBN8002), their non-transgenic parent JACK, and three conventional soybean varieties (Dongsheng3, Dongsheng7, and Dongsheng9) was investigated in juvenile channel catfish for eight weeks, and a safety assessment was performed. During the experiment, no difference in survival rate was observed in six groups. The hepatosomatic index (HSI) and condition factor (CF) showed no significant difference. Moreover, comparable feed conversion (FC), feeding rate (FR), and feed conversion ratio (FCR) were found between transgenic soybean and JACK groups. Assessment of growth performance showed that the weight gain rate (WGR) and specific growth rate (SGR) of channel catfish were consistent. In addition, there were no changes in enzyme activity indexes (lactate dehydrogenase (LDH), total antioxidant capacity (T-AOC), aspartate aminotransferase (AST) and alanine aminotransferase (ALT)) in channel catfish among treatments. The research provided an experimental basis for the aquaculture feed industry to employ transgenic soybean DBN9004 and DBN8002 for commercial purposes.

Effects of Lipopolysaccharide and Deoxynivalenol on the Survival, Antioxidant and Immune Response, and Histopathology of Crayfish (Procambarus clarkii).

Bacterial lipopolysaccharide (LPS) in the aquatic environment has been reported to cause diseases in red swamp crayfish (Procambarus clarkii). In addition, deoxynivalenol (DON) is one of the primary mycotoxins found in aquaculture. However, the potential synergistic toxic effects of LPS and DON on crayfish are yet to be fully elucidated. In this study, crayfish were exposed to LPS (1 mg kg-1), DON (3 mg kg-1), and their combination (1 mg kg-1 LPS + 3 mg kg-1 DON, L+D) for a duration of six days. Co-exposure to LPS and DON exhibited the lowest survival rate compared to the control or individual treatments with LPS or DON alone. In the initial stage of the experiment, the combined treatment of LPS and DON showed a more pronounced up-regulation of antioxidant and immune-related enzymes in the sera compared to the other treatment groups, with a fold change ranging from 1.3 to 15. In addition, the (L+D) treatment group showed a down-regulation of immune-related genes, as well as Toll pathway-related genes in the hepatopancreas compared to LPS or DON. Moreover, the (L+D) treatment group demonstrated a 100% incidence of histopathological changes in the hepatopancreas, which were significantly more severe compared to the other three groups. In conclusion, our study provides physiological and histopathological evidence that the co-exposure to LPS and DON exerted synergistic toxic effects on crayfish. The observed effects could potentially hinder the development of the crayfish aquaculture industry in China.

Detoxification of ochratoxin A by Lysobacter sp. CW239 and characteristics of a novel degrading gene carboxypeptidase cp4.

Ochratoxin A (OTA) is a potent mycotoxin that frequently contaminates agro-products and threatens food safety. A highly efficient OTA degrading strain Lysobacter sp. CW239 was isolated, and the OTA degradation characteristics were investigated. A novel OTA degrading gene carboxypeptidase cp4 was successfully cloned and characterized from CW239. The heterologous recombinant was constructed by gene cp4 and expression vector pET-32a(+) and overexpressed by E. coli BL21 CodonPlus™ (DE3). The recombinant protein rCP4 was purified, and the OTA-degrading activity was evaluated. Although OTA was efficiently degraded by CW239 (24-h degradation ratio of 86.2%), the 24-h OTA degradation ratio for rCP4 was only 36.8% at fairly high concentration (0.25 mg/mL) protein. The degraded product was obtained by immune affinity column (IAC) and determined by mass spectrometry (MS), and the degraded product was the less toxic ochratoxin α (OTα). Based on the serial investigations of this study, OTA might be simultaneously co-degraded by CP4 and another unknown degrading agent in that degrading strain.

Changes in the Prevalence of Induced Abortion in the Floating Population in Major Cities of China 2007-2014.

OBJECTIVE: Our aim was to assess the changes in induced abortion in different migrant groups in China between 2007 and 2014 and the contraceptive methods used prior to induced abortion. METHODS: The studies of two population-based cross sections were conducted in urban China, involving 9146 sexually active migrant women. Within the selected sociodemographic subgroups, the changes in the percentage of women who had induced abortions, the proportion of pregnancies ending in induced abortions, the causes of induced abortions, and the methods of contraception were identified. A chi-squared test was used to calculate the differences in induced abortion in the subgroups. RESULTS: Between 2007 and 2014, in the study groups from the major cities of China, the percentage of sexually active migrant women who had induced abortions increased 10.1%, from 21.8% to 24.0%. The proportion of pregnancies ending in induced abortions increased 23.7%, from 21.5% to 26.6%. Both of the aforementioned statistics increased significantly within most of the selected sociodemographic subgroups, especially in the 18-19 and 45-49 age groups. Over 50% of pregnancies were aborted in the cohabiting group, although this figure declined by 12.3% over the course of the seven-year study period. Contraceptive failure was the primary cause of induced abortion, although its contribution to induced abortion declined from 51.3% to 42.4%. The proportion of women not using contraception prior to induced abortion increased from 30.9% to 41.2%. CONCLUSION: The prevalence of induced abortion is high and continues to increase among sexually active migrant women in China. An increasing trend is forecasted over the next few decades. Special attention should be paid to the younger cohort of migrant women, especially 18-19-year-olds, and unmarried cohabitants, who are increasingly seeking induced abortions.