IRF11 regulates positively type I IFN transcription and antiviral response in mandarin fish, Siniperca chuatsi

In vertebrates, a total of eleven interferon (IFN) regulatory factors (IRFs), IRF1 to IRF11 are reported, with the conserved presence of IRF1 to IRF9 in all classes of vertebrates. However, IRF10 has been reported only in fish and birds, and IRF11 seems to be a fish specific IRF member. In this study, IRF11 in mandarin fish Siniperca chuatsi was found upregulated following virus infection, and IRF11 was localized constitutively in nucleus as revealed through immunofluorescence test. The overexpression and/or luciferase reporter assays showed that IRF11 can induce transcriptionally the ISRE activity, and the expression of type I IFNs, IFNc and IFNh, as well as the IFN-stimulated gene, Mx, thus inhibiting the Siniperca chuatsi rhabdovirus (SCRV) replication as indicated in the reduced expression of virus protein genes. It is thus suggested that IRF11 in mandarin fish and probably in other teleost fish can exert its antiviral effect through the upregulation of type I IFNs and ISGs

Reduction in the phytoplankton index of biotic integrity in riverine ecosystems driven by industrial activities, dam construction and mining: A case study in the Ganjiang River, China

Industrial activities, dam construction, and mining are three human activities important for societal and economic development. However, the effects of these activities on phytoplankton communities have been less quantitatively assessed than those on other groups, such as macroinvertebrates, fish, and periphytic algae. In the present study, we selected the Ganjiang River basin, a tributary of the Yangtze River as the representative area to develop a feasible phytoplankton index of biotic integrity (Phyto-IBI) to evaluate the effects of industrial activities, dam construction, and mining on the biotic integrity of riverine ecosystems. The results showed that the three activities greatly altered the abundance and composition of phytoplankton, with a reduction in phytoplankton species quantity and diversity and an increase in abundance. The health status of the Ganjiang River was fair, and the health statuses of industrial areas, dam areas, mining areas, and reference points were poor, poor, fair, and good, respectively. The three activities damaged the biotic integrity of the aquatic system. Moreover, compared to industrial activities and mining, dam construction is more harmful to aquatic systems in the Ganjiang River. The locally weighted regression scatter plot smoother (LOWESS) method showed that an ammonium nitrogen (NH3-N) concentration of 0.65 mg L-1 is the environmental protection threshold for planktonic biotic integrity in the Ganjiang River. This study not only quantitatively assesses phytoplankton responses to industrial activities, dam construction, and mining but also provides guidance regarding the ecological monitoring, assessment and protection of riverine ecosystems

Molecular characterization of a cyprinid fish (Ancherythroculter nigrocauda) TBK1 and its kinase activity in IFN regulation

TANK-binding kinase 1 (TBK1) plays a vital role in activating interferon (IFN) production and positively regulating antiviral response in mammals. Research on more species of fish is necessary to clarify whether the function of fish TBK1 is conserved compared to that in mammals. Here, a cyprinid fish (Ancherythroculter nigrocauda) TBK1 (AnTBK1) was functionally identified and characterized. The full-length open reading frame (ORF) of AnTBK1 consists of 2184 nucleotides encoding 727 amino acids and contains a conserved Serine/Threonine protein kinase catalytic domain (S_TKc) in the N-terminal, similar to TBK1 in other species. The transcripts of AnTBK1 were found in all the tissues evaluated and the cellular distribution indicated that AnTBK1 was localized in the cytoplasm. In terms of functional identification, AnTBK1 induced a variety of IFN promoter activities as well as the expression of downstream IFN-stimulated genes (ISGs). In addition, AnTBK1 interacted with and significantly phosphorylated IFN regulatory factor 3 (IRF3), exhibiting the canonical kinase activity of TBK1. Finally, AnTBK1 presented strong antiviral activity against spring viremia of carp virus (SVCV) infection. Taken together, our research on the features and functions of AnTBK1 demonstrated that AnTBK1 plays a central role in IFN induction against SVCV infection

Reduction in the phytoplankton index of biotic integrity in riverine ecosystems driven by industrial activities, dam construction and mining: A case study in the Ganjiang River, China

Industrial activities, dam construction, and mining are three human activities important for societal and economic development. However, the effects of these activities on phytoplankton communities have been less quantitatively assessed than those on other groups, such as macroinvertebrates, fish, and periphytic algae. In the present study, we selected the Ganjiang River basin, a tributary of the Yangtze River as the representative area to develop a feasible phytoplankton index of biotic integrity (Phyto-IBI) to evaluate the effects of industrial activities, dam construction, and mining on the biotic integrity of riverine ecosystems. The results showed that the three activities greatly altered the abundance and composition of phytoplankton, with a reduction in phytoplankton species quantity and diversity and an increase in abundance. The health status of the Ganjiang River was fair, and the health statuses of industrial areas, dam areas, mining areas, and reference points were poor, poor, fair, and good, respectively. The three activities damaged the biotic integrity of the aquatic system. Moreover, compared to industrial activities and mining, dam construction is more harmful to aquatic systems in the Ganjiang River. The locally weighted regression scatter plot smoother (LOWESS) method showed that an ammonium nitrogen (NH3-N) concentration of 0.65 mg L-1 is the environmental protection threshold for planktonic biotic integrity in the Ganjiang River. This study not only quantitatively assesses phytoplankton responses to industrial activities, dam construction, and mining but also provides guidance regarding the ecological monitoring, assessment and protection of riverine ecosystems

The intestinal microbiome of an Indo-Pacific humpback dolphin (Sousa chinensis) stranded near the Pearl River Estuary, China

The mammalian intestinal microbiome is critical for host health and disease resistance. However, the cetacean intestinal microbiota remains relatively unexplored. By using high-throughput 16S rRNA gene sequencing, we analyzed intestinal bacterial samples from an Indo-pacific humpback dolphin (Sousa chinensis) stranded near the Pearl River Estuary in China. The samples included 3 anatomical regions (foregut, midgut, and rectum) and 2 anatomical locations (content and mucus). Our analyses revealed that the dolphin intestinal bacteria contained 139 operational taxonomic units (OTUs), dominated at the phyla level byFirmicutes(47.05% in the content; 94.77% in the mucus), followed byBacteroidetes(23.63% in the content; 1.58% in the mucus) andGammaproteobacteria(14.82% in the content; 2.05% in the mucus). The intestinal bacteria had a small core community (15 OTUs, accounting for 99.74% of the reads), some of which could be potentially pathogenic to both human and dolphins. As an alternative to sampling the dolphin intestinal bacteria, fecal sampling could be used. Additionally, function potentials such as, xenobiotics biodegradation, beta-lactam resistance, and human disease-related pathways, were detected in the dolphin intestinal bacteria. These findings provide the first baseline knowledge of the intestinal microbiome of the Indo-Pacific humpback dolphin, which may offer new insights into cetacean conservation by using microbial surveillance

Expression of LamB Vaccine Antigen inWolffia globosa(Duck Weed) Against Fish Vibriosis

Vibriosis is a commonly found bacterial disease identified among fish and shellfish cultured in saline waters. A multitude ofVibriospecies have been identified as the causative agents. LamB, a member of outer membrane protein (OMPs) family of these bacteria is conserved among allVibriospecies and has been identified as an efficient vaccine candidate against vibriosis. Rootless duckweed (Wolffia) is a tiny, edible aquatic plant possessing characteristics suitable for the utilization as a bioreactor. Thus, we attempted to express a protective edible vaccine antigen against fish vibriosis in nuclear-transformedWolffia. We amplifiedLamBgene from virulentVibrio alginolyticusand it was modified to maximize the protein expression level and translocate the protein to the endoplasmic reticulum (ER) in plants. It was cloned into binary vector pMYC under the control of CaMV 35S promoter and introduced intoWolffia globosabyAgrobacterium-mediated transformation. Integration and expression of theLamBgene was confirmed by genomic PCR and RT-PCR. Western blot analysis revealed accumulation of the LamB protein in 8 transgenic lines. The cross-protective property of transgenicWolffiawas evaluated by orally vaccinating zebrafish through feeding fresh transgenicWolffiaand subsequently challenging with virulentV. alginolyticus. High relative percent survival (RPS) of the vaccinated fish (63.3%) confirmed that fish immunized with transgenicWolffiawere well-protected fromVibrioinfection. These findings suggest thatWolffiaexpressed LamB could serve as an edible plant-based candidate vaccine model for fish vibriosis and feasibility of utilizingWolffiaas bioreactor to produce edible vaccines

Nitrate removal from low carbon-to-nitrogen ratio wastewater by combining iron-based chemical reduction and autotrophic denitrification

Nitrate removal from low carbon-to-nitrogen ratio (C/N) wastewater has always been a knotty problem due to the deficiency of organics. Here, a novel iron-based chemical reduction and autotrophic denitrification (ICAD) system was developed. ICAD system could maintain average nitrate removal efficiency of 97.2% for 131 days with feeding 20.3 mg NO3--N/L at hydraulic retention time (HRT) of 24 h. The optimal operational conditions was further explored, and results demonstrated that average nitrate removal efficiency of 85.5% and 98.4% could be achieved at HRT of 12 h and 24 h (influent 20.3 mg NO3--N/L), while average nitrate removal efficiency could reach 96.3% at optimal HRT of 12 h (influent 10.3 mg NO3--N/L). Hydrogenophaga, which can carry out hydrogenotrophic denitrification, showed a positive correlation with nitrate removal efficiency of the ICAD system. Low cost and simple operation make the ICAD system suitable for large-scale application.</p

Zebrafish prmt7 negatively regulates antiviral responses by suppressing the retinoic acid-inducible gene-I-like receptor signaling

Arginine methylation is a post-translational modification in histone and nonhistone proteins that can affect numerous cellular activities. Protein arginine methyltransferase 7 (Prmt7), a type III arginine methyltransferase, catalyzes the formation of stable monomethylarginines of histones. The role of PRMT7 in virus-induced innate immunity signaling, however, remains largely unknown. We demonstrate that zebrafish prmt7 could be inhibited by spring viremia of carp virus (SVCV) and grass carp reovirus (GCRV) infection. The overexpression of prmt7 suppresses cellular antiviral responses that are partially dependent on the arginine methyltransferase activity of prmt7. Consistently, prmt7-null zebrafish were more resistant to SVCV or GCRV infection, exhibiting enhanced expression of key antiviral genes and fewer necrotic cells in the liver and kidney upon viral infection. Furthermore, we established a zebrafish model to investigate grass carp hemorrhagic disease. Our findings suggest that by suppressing the RIG-I-like receptors signaling, zebrafish prmt7 negatively regulates antiviral responses, indicating the vital role of prmt7 and its arginine methyltransferase activity in innate immunity

Responses of the macroinvertebrate taxonomic distinctness indices of lake fauna to human disturbances in the middle and lower reaches of the Yangtze river

In recent decades, floodplain lakes have been among the most endangered ecosystems in the world due to human activities, and they are experiencing severe degradation in ecological function and declines in biodiversity. Previous studies have mostly concentrated on the effects of human disturbances on the traditional taxonomic structure of aquatic communities, but little is known about the responses of other facets of biodiversity measures (e.g., phylogenetic relatedness) to anthropogenic impacts. Here, we examined the effectiveness of species richness and taxonomic distinctness (TD) indices (the average taxonomic distinctness, Delta(+), and variation in taxonomic distinctness, Lambda(+)) in determining anthropogenic effects based on four datasets of macroinvertebrate communities in 31 shallow lakes in the Yangtze floodplain. The species composition and number of entire taxa and three subsets (mollusk-, insect- and oligochaete-only taxa) were all significantly different among the five lake groups, with the highest species richness in the river-connected lakes, followed by the oxbow, macrophytic, macrophytic-algal transition and algal lakes. For the TD indices, only the Lambda(+) of entire taxa showed clear differences among lake groups, with the highest values in the algal lakes and the lowest values in the river-connected lakes. However, the TD indices based on the other three datasets showed no differences and did not clearly reveal the degree of anthropogenic disturbances as we expected. However, the spatial pattern of species richness was largely influenced by lake area rather than by water quality. In contrast, the TD indices were insensitive to lake area and responded more readily to water quality than species richness. We proposed that the TD indices provided a useful complement to traditional diversity indices (e.g., species richness) and could be considered as a potential bioassessment metric for detecting the environmental degradation level of freshwater lakes