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Microplastics have become a worldwide pollutant, widely discovered in soil, air and aquatic environment. Microplastics have been found in habitats where crayfish (Procambarus clarkii) cultivated, but the impact of microplastics on crayfish remains unclear. In this study, after 21-day dietary exposure, polyethylene (PE) particles were found to accumulate in intestine, hepatopancreas, gills and hemolymph of crayfish. Furthermore, PE particles can still be detected in these tissues after a 7-day depuration in clean water. PE retained in these tissues caused oxidative stress responses, as indicated by the change of oxidative-stress-related index, such as the increase of H 2 O 2 level and SOD activity. PE exposure also caused hemocytic encapsulation in crayfish hepatopancreas and increase of mucus secretion in intestine. Moreover, PE exposure affected the microbiota balance in crayfish, by reducing the total microbiota abundance and altering the proportions of many bacterial families. Interestingly, results showed that PE exposure led to of lower numbers of hemocytes and declination of phenoloxidase activity. Finally, PE exposure induced the expression of immune-related genes, including transcription factors and antimicrobial peptides. Taken these together, we conclude that PE microplastics exert considerable toxic effects on crayfish and are a potential threat to crayfish aquaculture and consumption. This study provides basic toxicological data toward quantifying and illuminating the impact of PE microplastics on freshwater animals. [Display omitted] • Polystyrene microplastics accumulated in several tissues of crayfish and caused histopathological changes. • Polystyrene microplastics induced oxidative stress and immune responses in crayfish. • Polystyrene microplastics induced gut microbiota dysbiosis in crayfish. [ABSTRACT FROM AUTHOR]

Hsp70 is the most strongly induced in response to various cellular stresses and a good candidate for investigating its role in tissue injury. We firstly cloned full-length cDNA of hsp70 from Paramisgurnus dabryanus ( PdHsp70 ) by RACE method (GenBank: KP402408.1 ). Then regeneration and inflammation of fin were established by amputation and scratch respectively. Quantitative RT-PCR detected the PdHsp70 began to increase rapidly its expression at 1 days post amputation (dpa) and reached the peak at 2 dpa during fin regeneration. Its expression was also up-regulated at 2 days post scratch (dps) of inflammation but still significant weaker in comparison with it in regenerated fin at 2 dpa. Next, immunohistochemistry analysis of PdHsp70 showed that PdHsp70 located mainly in the deeper epidermis of regenerated fin and was stronger than its expression in the scratched inflammatory fin which was involved in whole epidermal. SDS-PAGE and Western blotting confirmed that the PdHsp70 protein expressed efficiently in Escherichia coli BL21. These findings have implied that PdHsp70 are implicated in different regulation of regeneration and inflammation in response to injury stimulation. During the regeneration, it is involved in the formation of wound epidermis by mediating cellular protection whereas it can modulate inflammatory by activating the innate immune response. [ABSTRACT FROM AUTHOR]

Abstract: Heat shock protein 60 (Hsp60) is a kind of highly conserved immunogenic molecule involved in a wide range of biochemical processes in response to external stressors. Its multifunction in regulating immune responses and modulating signal pathway interests us in investigating its role in fin regeneration that has become an excellent and interesting model for studying the molecular basis of morphogenesis. We firstly clarified basical process and crucial period of caudal fins regeneration in Paramisgurnus dabryanus by histological analysis. Then we cloned full-length cDNA of hsp60 from P. dabryanus (designated as PdHsp60) by RACE method. The cDNA contains a 124 bp 5′UTR, a 1731 bp open reading frame (ORF) encoding 576 amino acids and a 510bp 3′UTR (Accession no.: KF544774). The phylogenetic tree shows that the PdHsp60 fits within the hsp60 clade. And quantitative RT-PCR detected the PdHsp60 began to increase rapidly its expression at 1 dpa and reached its peak at 2 dpa. Next, spatial distribution analysis of PdHsp60 in fins showed that PdHsp60 located mainly in the deeper lay of regenerated epidermis when PdHsp60 expressed most. After the PdHsp60 had been cloned into the pET-32a vector, SDS-PAGE and Western blotting analysis confirmed that the PdHsp60 protein was efficiently expressed in Escherichia coli BL21. These findings have revealed that PdHsp60, a highly conserved gene related to the innate immune system and stress response during vertebrate evolution, is involved in response to wounding stimulation—in the formation of wound epidermis which occurs as the first phase of fin regeneration after fin amputation in caudal fin regeneration. [Copyright &y& Elsevier]

Yellow River carp (Cyprinus carpio) is an economically-important freshwater fish. It is the common host of the epizootic bacterium Flavobacterium columnare, a common fish pathogen that causes columnaris disease resulting in aquacultural losses. However, information on the functions and mechanisms of the immune system of Yellow River carp infected with F. columnare is limited. Therefore, the aim of this study is to evaluate the genetic and histopathological effects of an experimentally-induced F. columnare infection in Yellow River carp. Sixty fish were divided into control (CT group) and challenged groups. The gills were collected for histological and transcriptome analysis to understand the host immune response after challenge with F. columnare. The infected fish of the IF group presented typical columnaris disease symptoms and higher mortality, as well as histological changes. However, some challenged fish showed asymptomatic infection (IC group). Additionally, there were 1776 significant differentially-expressed genes (DEGs) between the IC and CT groups, 1853 DEGs between the IF and CT groups, and 1836 DEGs between the IF and IC groups, All the DEGs were classified into three gene ontology categories, which were allocated to 158 KEGG pathways. Moreover, immune-related genes were confirmed by qRT-PCR. we quantified the level of IL-1, IL-6, TNF-α and IL-8 by ELISA. The results showed the highest expression levels of inflammatory cytokines as well as stress proteins and the adhesion molecules in the lF group, which may contribute to severe infection, and a higher case fatality rate, while the high expression of chemokines, costimulatory molecules and the up regulation of antigen presentation function could help the carp resist F. columnare infection. • The pathological changes of carp gills were caused by the infection of F. columnare. • Transcriptome can provide immune-related DEGs of carp infected with F. columnare. • Inflammatory cytokines may contribute to higher case fatality in the infected carp. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we identified a sex-specific DNA marker using randomly amplified polymorphic DNA (RAPD) fingerprinting in Yellow River carps (Cyprinus carpio from the Yellow River). Two hundred and twenty random primers were used in pooled DNA samples and individual DNA samples from male and female fish for RAPD fingerprinting. When using the primer S2107, a novel sex-specific PCR product was identified in all male individuals. DNA sequencing revealed that this 909 bp long DNA fragment has a low similarity to a repetitive sequence in zebrafish Danio rerio. In order to confirm the amplification results, two primers were designed within the male-specific sequence in order to amplify the sex-specific fragment from genomic DNA of male and female carps for sexing by PCR. The results indicated bands specific for males but not females. Respective results were obtained in dot blot and Southern blot hybridization experiments when using this sex-specific fragment as the probe. The sex-specific pattern was observed in 30 individuals from three separate common carp stocks, suggesting that the sequence is conserved in common carp species. However, no hybridization signals were found in grass carps Ctenopharyngodon idella, which are related to common carps. We submit to use this sex-specific fragment as a marker to rapidly and accurately identify the gender of Yellow River C. carpio. Furthermore, the sex-specific chromosome region may be characterized and used to study mechanisms of chromosome evolution in this fish species. [Copyright &y& Elsevier]