72 research outputs found

    Transcriptome analysis of <em>Marsupenaeus japonicus</em> hepatopancreas during WSSV persistent infection

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    White Spot Syndrome Virus (WSSV) can cause a large-scale death of cultured shrimp and significant damage to the shrimp farming industry. Marsupenaeus japonicus is one of the world's most important economically farmed shrimp. This study found that some M. japonicus survived the spontaneous outbreak of WSSV. Surprisingly, these virus-carrying shrimp showed no apparent illnesses or outbreaks of white spot disease in the subsequent cultivation, and their body size was substantially smaller than healthy shrimp, indicating a long-term fight between the host and the virus. To investigate this interesting phenomenon, we analyzed the transcriptomes of healthy shrimp and survived shrimp through the RNA-Seq platform, attempting to reveal the underlying molecular mechanism of the struggle between M. japonicus and WSSV. Transcriptional analysis showed that a total of 37,815 unigenes were assembled, with an average length of 1,193.34 bp and N50 of 2,049 bp. In the KEGG pathway, enrichment analysis of DEGs pathways related to immunity, biosynthesis, and growth metabolism was enriched, including pentose phosphate pathway, glycerophospholipid metabolism, fatty acid biosynthesis, Wnt signaling pathway, biosynthesis of amino acids, ascorbate, and aldarate metabolism. Our data showed a delicate balance between M. japonicus and WSSV infection: On the one hand, WSSV infection can cause host metabolism and biosynthesis disorders in the host, and the virus consumes a portion of the material and energy required for shrimp average growth and reproduction. If WSSV infection persisted for a long time, then the growth rate of M. japonicus decreased. On the other hand, the host can regulate immune defense to resist subsequent viral infection. This study reveals the underlying molecular mechanism of a long-term battle of M. japonicus against WSSV infection, providing novel insights for preventing WSSV persistent infection in M. japonicus and other farmed shrimp species

    PtrA regulates prodigiosin synthesis and biological functions in Serratia marcescens FZSF02

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    Serratia marcescens is a gram-negative bacterium that is able to produce many secondary metabolites, such as the prominent red pigment prodigiosin (PG). In this work, a ptrA-disrupted mutant strain with reduced PG production was selected from Tn5 transposon mutants. RT–qPCR results indicated that ptrA promoted elevated transcription of the pig gene cluster in S. marcescens FZSF02. Furthermore, we found that ptrA also controls several other important biological functions of S. marcescens, including swimming and swarming motilities, biofilm formation, hemolytic activity, and stress tolerance. In conclusion, this study demonstrates that ptrA is a PG synthesis-promoting factor in S. marcescens and provides a brief understanding of the regulatory mechanism of ptrA in S. marcescens cell motility and hemolytic activity

    The effect of water temperature on the pathogenicity of decapod iridescent virus 1 (DIV1) in Litopenaeus vannamei

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    Decapod iridescent virus 1 (DIV1) has caused huge losses to the shrimp breeding industry in recent years as a new shrimp virus. In this study, white leg shrimp, Litopenaeus vannamei, were cultured at different temperatures (26 ± 1 °C and 32 ± 1 °C) and the same salinity, then infected with DIV1 by intramuscular injection to determine the effects of water temperature on viral infection. The DIV1 copy counts in the gills, hepatopancreas, pleopods, intestines, and muscles of L. vannamei were measured in samples collected at 6, 12, and 24 h post-infection (hpi), and the survival rate of L. vannamei was assessed every 6 h after infection. At 96 hpi, the survival rates of L. vannamei in the high (32 ± 1 ℃) and standard (26 ± 1 ℃) water temperature groups were 2.22% and 4.44%, respectively. The peak time of mortality in the high-water temperature group was 6 h earlier than in the standard water temperature group. After 24 hours of DIV1 infection, the DIV1 copy counts in the standard water temperature treatment group were significantly higher than those in the high-water temperature treatment group. The tissues with the highest virus copy counts in the standard and high-temperature groups were the intestines (2.9×1011 copies/g) and muscles (7.0×108 copies/g). The effect of temperature on the pathogenicity of DIV1 differs from that of other previously studied viruses, such as white spot syndrome virus, Taura syndrome virus, and infectious hypodermal and hematopoietic necrosis virus, because the high-water temperature did not mitigate the damage caused by DIV1 infection

    Survival and immune response of white shrimp Litopenaeus vannamei following single and concurrent infections with WSSV and Vibrio parahaemolyticus

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    The survival and immune responses of Litopenaeus vannamei were evaluated during white spot syndrome virus (WSSV) or Vibrio parahaemolyticus single and concurrent infections. The mortality, WSSV load, activities of 4 immune enzymes: acid phosphatase (ACP), alkaline phosphatase (AKP), peroxidase (POD) and superoxide dismutase (SOD), and the transcription of Evolutionarily Conserved Signaling Intermediate in Toll pathways of L.vannamei (LvECSIT) were quantified at 0, 3, 6, 12, 24, 48, 72 and 96 h post-infection (pi). The results showed: (i) the cumulative mortality of the co-infection group (WSSV and V. Parahaemolyticus 83%) was significantly lower than the WSSV infection group (97%) (P < 0.05) at 96 hpi; (ii) copies of WSSV in the co-infection group were significantly lower than that of the single infection group from 24 to 96 hpi (P < 0.05); (iii) ACP, AKP,POD and SOD activity in the gills of the co-infection group was higher than that of the WSSV group at12, 48 and 96 hpi (P < 0.05).The expression of LvECSIT mRNA in the co-infection group was significantly higher than in the WSSV infection group from 12 to 72 hpi (P < 0.05).The results indicate that proliferation of WSSV is inhibited by V.parahaemolyticus infection. In addition, infection with WSSV alone causes a significant reduction in some immune responses of shrimp than co-infection with WSSV and V.parahaemolyticus occurs at 26 °C. Third, LvECSIT, an essential member of TLR signaling pathway might play a crucial role in shrimp defense against WSSV – Vibrio co-infection

    Metagenomic Analysis of Bacterial Communities and Antibiotic Resistance Genes in Penaeus monodon Biofloc-Based Aquaculture Environments

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    Biofloc technology (BFT) is one of the most promising technologies in global aquaculture for the purpose of improving water quality, waste treatment, and disease prevention in intensive aquaculture systems. However, characterization of the microbial species and antibiotic resistance potentially present in biofloc-based aquaculture environments is needed. In this study, we used high-throughput sequencing technology to comprehensively compare the bacterial communities in mariculture ponds of Penaeus monodon (P. monodon), by testing of water, biofloc, and intestine of P. monodon. Operational taxonomic units (OTUs) cluster analysis showed that the nine samples tested divided into 45 phyla and 457 genera. Proteobacteria was the dominant bacteria in water, biofloc and prawn intestine. In biofloc and intestine, the Ruegeria (2.23–6.31%) genus represented the largest proportion of bacteria, with Marivita (14.01–20.94%) the largest group in water. Microbial functional annotation revealed that in all the samples, genes encoding metabolism were predominant. The antibiotic resistance gene annotation showed the highest absolute abundance of patB, adeF, OXA-243, and Brucella_suis_mprF from Proteobacteria. PatB (11.33–15.01%), adeF (15.79–18.16%), OXA-243 (35.65%), and Brucella_suis_mprF (10.03%) showed the highest absolute abundance of antibiotic resistance genes in water, biofloc, and intestines, respectively. These findings may greatly increase our understanding of the characteristics of the microbiota of shrimp biofloc-based aquaculture systems and the complex interactions among shrimp, ambient microflora, and environmental variables. It provides a reference basis for policy on breeding, environmental safety, and maintaining food safety in the production of P. monodon

    互联网防火墙对中国民主发展的影响

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    As a special censorship system, China’s Internet firewall plays an important role in Chinese society.The Internet firewall is a controversial social action in China’s democratic development.The Internet firewall efficiently protects China’s economic environment. Similarly,Because of its rigorous censorship and guidance of information, it makes controversy about its role in the development of democracy in China. The Internet firewalls in China largely limit Chinese media freedom, information freedom and public opinion freedom, that through a regulatory and directional approach. At the same time, with the continuous emergence of new media, to some extent, new media also impacts the review of Internet firewalls.This study has studied the function of Internet firewalls that through the analysis of literatures, and hopes to draw the conclusion that the effects of the Internet firewall on the development of Chinese democracy. This study first analyzes the literature through discourse analysis and structured focused comparison analysis, and then analyzes the function of Internet firewall through function analysis theory. The results show that China's Internet firewall is closely related to China's special political and economic structure.It may lead China to a deliberative democracy, but under a special political and economic structure, it is accompanied by great uncertainty.According to this study, a means of deliberative democracy is being established by the Internet firewall, but because of its continued existence, the special political environment in China may persist for a long period.Peace and devlopmen

    The secondary bacterial infection caused by WSSV outbreaks impacts shrimp Marsupenaeus japonicus’ growth as well as its intestinal microbiota’s composition and function

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    Intestinal microbiota homeostasis is a complex ecosystem and is essential for promoting aquatic animals’ growth. Invading pathogens can cause dynamical composition and structure change in the hosts’ microbiota due to this affecting their functions. WSSV is one of the most common and dangerous shrimp pathogens, which leads to white spot disease with too high mortality. A few studies on shrimp intestinal microbiota mainly focused on the changes during acute infection stage. Marsupenaeus japonicus is one of the most cultured shrimp with a decent ability to cope with environmental changes. In the current research, using M. japonicus as a model, we compared the differences of intestinal microbiota between healthy shrimp and the shrimp that survived through the WSSV outbreak. Our study showed that compared to the healthy M. japonicus, the WSSV outbreak disrupted intestinal microbiota structure in the survived shrimp: There was less potential beneficial bacteria and more harmful bacteria. Furthermore, the diversity and total abundance of intestinal microbiota in WSSV-survived shrimp increased significantly. On top of that, a metagenomic analysis by PICRUSt suggested that the changed intestinal microbiota could help the host to combat the secondary bacterial infections caused by WSSV outbreaks by regulating cell growth and death, reducing cell motility, improving energy metabolism, and increasing intestinal enzyme activities regardless the smaller sizes of WSSV-survived shrimp. This could be a result of excessive energy consumption and reduced nutrient-absorbing intestinal microbiota. Our study indicated that shrimp intestinal microbiota plays a fundamental role in combating against secondary infections and regulating the hosts’ growth post WSSV outbreaks. The eventual goal is to development of more efficient diagnostics and therapeutic strategies

    Evolution of domains and grain boundaries in graphene: a kinetic Monte Carlo simulation

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    To understand the mystery of preferential mismatching angle of grain boundaries (GB) in multicrystalline graphene observed experimentally, a systematic kinetic Monte Carlo simulation is designed to explore how a two-dimensional amorphous carbon system evolves into graphene domains and GBs. The details of the evolution, including the graphene domain nucleation, growth, rotation, coalescence, the corresponding GB motion, rotation and elimination, are observed. One hundred individual simulations with different initial configurations are performed and our simulation confirms that it is the Stone-Wales (SW) transformation that dominates the GB fast annealing process, and the results show that graphene domains with small angle GBs (15 degrees) tend to become large angle (approximate to 30 degrees), which is a consequence of the fact that the formation energies of GBs have two minima at 0 degrees and 30 degrees. The behavior of the formation energies is also responsible for the distribution of GBs' mismatch angles obtained by our simulations, which is very similar to those broadly observed experimentally.ope

    Molecular Mechanism of MiR-136-5p Targeting NF-κB/A20 in the IL-17-Mediated Inflammatory Response after Spinal Cord Injury

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    Background/Aims: The pathophysiology of spinal cord injury (SCI) results in serious damage to the human body via an increase in the secondary biological processes imposed by activated astrocytes. Abnormal expression of microRNAs after SCI has become a potential research focus. However, the underlying mechanisms are poorly understood. Methods: SCI models were established in rats using Allen’s method, and the BBB scoring method was employed to assess locomotor function. Lentivirus was used to infect rat astrocytes and SCI rats. Real-time PCR and antibody chip were used to measure gene expression and cytokine secretion. Western blot analysis was employed to detect protein expression. HE staining was used to assess the histological changes in SCI. The immunohistochemical staining of A20 and p-NF-κB in SCI was also analyzed. Results: The in vitro experiment showed that miR-136-5p up-regulated the expression of p-NF-κB by down-regulating the expression of A20 so that astrocytes produced inflammatory factors and chemokines. The in vivo experiment indicated that overexpressed miR-136-5p promoted the production of inflammatory factors, chemokines and p-NF-κB in SCI rats, whereas it inhibited the expression of A20 protein and increased inflammatory cell infiltration and injuries in the spinal cord. Conclusion: The current findings indicate that silencing miR-136-5p effectively decreased inflammatory factors and chemokines and protected the spinal cord via NF-κB/A20 signaling in vivo and in vitro. In contrast, overexpression of miR-136-5p had the opposite effect
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