Gut microbiota communities of reciprocal hybrids from koi (Cyprinus carpio) and goldfish (Carassius auratus) are more similar to koi than goldfish.

AIMS: To investigate the gut microbiota communities of reciprocal hybrids and inbred lines of koi (Cyprinus carpio) and goldfish (Carassius auratus), as well as the genetic effect of intestinal microbiota between hybrids and parents. METHODS AND RESULTS: The reciprocal hybrids and inbred lines derived from the parents, koi and goldfish, were established. Then, the bacterial 16S rRNA gene of intestinal contents was sequenced using Illumina Miseq PE300. Alpha diversity in the two types of hybrids was lower than inbred lines of koi or goldfish and was highest in goldfish, followed by koi. For beta diversity, microbial samples presented clear clusters and the two types of hybrids were more similar to koi than goldfish, indicating the gut microbiota of the reciprocal hybrids was more affected by koi. The dominant phyla were Proteobacteria, Actinobacteria and Firmicutes in koi, and Proteobacteria, Fusobacteria and Actinobacteria in goldfish, and Proteobacteria, Fusobacteria and Firmicutes in the reciprocal hybrids. In the case of Proteobacteria, the dominant classes were Alphaproteobacteria and Gammaproteobacteria in four fish. The dominant genera were norank_f_Rhizobiales_Incertae_Sedis and Plesiomonas in koi, Cetobacterium in goldfish, and Cetobacterium and ZOR0006 in the reciprocal hybrids. PICRUSt1 predictive function analysis showed that the reciprocal hybrids had lower abundance in the most functional categories than koi and goldfish. CONCLUSIONS: The gut microbiota of reciprocal hybrids was more affected by koi. Two types of hybrids possessed the same dominated phyla and were different from the inbred lines of koi and goldfish. SIGNIFICANCE AND IMPACT OF THE STUDY: It enhanced our understanding of gut microbiota of hybrid lines of goldfish and koi and provided a new perspective for the selective breeding of gut microbiota traits.

Microplastics intake and excretion: Resilience of the intestinal microbiota but residual growth inhibition in common carp.

Aquatic animals can be influenced by exposure to microplastics (MPs), but little is known about their recovery capacity following MPs excretion. Here, common carp were exposed to environmentally relevant concentrations of MPs for 30 days and followed by MPs excretion for another 30 days. Growth, isotopic and elemental compositions and intestinal microbiota were investigated. We found that fish growth was not influenced by exposed to MPs but was significantly reduced following MPs excretion, indicating a delayed effect on growth. MPs intake and excretion, however, had no obvious effects on isotopic and elemental compositions. MPs altered the community structure and composition of intestinal microbiota and might reduce functional diversity. After MPs excretion, interestingly, bacterial community structures of MPs treatments were grouped together with the control, suggesting the general resilience of fish intestinal microbiota. Nevertheless, high abundance of pathogenic Shewanella, Plesiomonas and Flavobacterium was observed in MPs treatments but did not affect the functional potential of intestinal microbiota. The results of this study provide new information for the application of adverse outcome pathway (AOP) in MPs, suggesting the necessity of paying attention to recovery assay following MPs intake in the development of AOP frameworks.

Ecological stoichiometric and stable isotopic responses to microplastics are modified by food conditions in koi carp.

Microplastics (MPs) can be easily taken up by a wide range of aquatic animals and cause blockage of the digestive tract leading to starvation. Meanwhile, aquatic organisms are facing threats posed by food restriction in both wild and cultured environment. Little knowledge, however, exists on how MPs interact with food conditions to affect aquatic animals. Here, koi carp were exposed to polystyrene MPs (0, 100 or 1000 µg/L) under controlled feeding (satiated or starved) for 30 or 60 days. MPs reduced and interacted synergistically with food conditions on growth after 30 days but antagonistically after 60 days. MPs reduced crude lipid and carbohydrate but increased and antagonistically interacted with feeding conditions on crude protein. Food conditions interacted with MPs on C, N and P but stoichiometric responses were decoupled with macromolecules changes. Food conditions antagonistically interacted with MPs on δ13C after 60 days. Linear discriminant analysis revealed that C:P and N:P were the two most important measured parameters accounting for the response of koi towards MPs and food restriction, presenting an antagonistic interaction of MPs and food status with the prolonged exposure duration.

Status of Gene Methylation and Polymorphism in Different Courses of Ulcerative Colitis and Their Comparison with Sporadic Colorectal Cancer.

BACKGROUND: The objective of this study is to explore the common genetic and epigenetic mechanism of ulcerative colitis (UC) and sporadic colorectal cancer (SCRC) by observing genes methylation level and single nucleotide polymorphisms (SNPs) of different disease courses in UC and SCRC. METHODS: Two hundred subjects were enrolled, including 40 in the healthy control (HC) group, 50 in the short disease course UC group (SUC), 52 in the long disease course UC group (LUC), and 58 in the SCRC group. Methylation-specific polymerase chain reaction was used to detect the methylation of MINT1 and cyclooxygenase 2 (COX-2) gene. Single nucleotide polymorphisms of interleukin (IL)-23R rs10889677 and IL-1ß rs1143627 were detected by Sanger sequencing. RESULTS: Compared with HCs (32.5%), methylation level of MINT1 was significantly increased in SCRC (67.2%; P = 0.001) and was a risk factor for CRC (odds ratio, [OR] 4.26). The methylation ratios of COX-2 were 95.0%, 58.0%, 23.1%, and 24.1% in HC, SUC, LUC, and SCRC, respectively, which were negatively correlated with the disease course of UC (r = -0.290). Hypermethylation of COX-2 was a protective factor for SUC (OR, 0.11), LUC (OR, 0.02), and SCRC (OR, 0.03; P < 0.05). Compared with HCs, rs10889677 allele A was a risk factor for SUC and LUC, and rs1143627 allele T was a protective factor for SUC and LUC. Genotype TT was a protective factor for SUC. CONCLUSION: The hypomethylation of COX-2 gene was a common risk factor and epigenetic modification for UC and SCRC, which might be one of the mechanisms through which UC patients were susceptible to CRC. The hypermethylation of MINT1 was a risk factor for SCRC but not for UC; alleles of IL-23Rrs10889677 and IL-1ßrs1143627 were related to UC but not to SCRC.

Community structure and functional diversity of the plastisphere in aquaculture waters: Does plastic color matter?

Microplastics (MPs) serve as a niche for colonization of biofilm-forming microorganisms, termed as plastisphere. Distinct microbial assemblages between MPs and surrounding waters have been well reported, but little is known about driving factors affecting biofilm development on plastic surfaces. Here, to investigate the influence of plastic colors on microbial assemblages, we performed a biofilm incubation experiment, in an aquaculture pond, using MPs in colors (blue, yellow and transparent) that commonly found in the aquatic environments for 30 days. We examined the community structure and function of plastisphere by using 16S rRNA sequencing. The results showed that plastisphere communities exhibited a higher diversity and evenness compared with the water community. MPs especially the blue MPs had more unique species, which might indicate a plastic color/additive-driven selection of microorganisms on MPs. A significant distinctness in bacterial community composition between MPs and the water was found, mainly caused by large amounts of Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium but trace amounts of Microcystis_PCC-7914 on MPs. Due primarily to rich in Aquabacterium but lack of norank_f__norank_o__1-20 on blue MPs than on transparent and yellow MPs, a clear separation between plastisphere communities of three colors of MPs was also observed. Moreover, compared with the water column, the metabolic pathways, e.g., transport and metabolism of amino acid, carbohydrate and inorganic ion, on plastisphere especially those of blue MPs were generally enriched. Biofilms colonizing on blue MPs appeared to have a higher functional diversity than those on transparent or yellow MPs. These results might suggest that plastic colors have impacts on the community structure and functional diversity of plastisphere.

Single and combined effects of microplastics and cadmium on the cadmium accumulation, antioxidant defence and innate immunity of the discus fish (Symphysodon aequifasciatus).

Microplastics (MPs) have the potential to interact with the toxicity of other common environmental contaminants, such as heavy metals. Here, we investigated the impacts of polystyrene-MPs (32-40 µm), cadmium (Cd) and their combination on early juveniles of the discus fish (Symphysodon aequifasciatus) in relation to Cd accumulation, antioxidant defence and innate immunity. Animals were exposed to three concentrations of MPs (0, 50 or 500 µg L-1) crossed with two levels of Cd (0 or 50 µg L-1) for 30 days. Our findings showed that MPs and Cd had no adverse effects on growth and survival. Under exposure to Cd, however, accumulation of Cd in the body of fish decreased with increasing MP concentrations as supported by a reduced metallothionein content. The activities of superoxide dismutase and glutathione peroxidase increased with MPs but decreased with Cd. MPs, Cd or the mixture increased catalase activity, despite an antagonistic interaction between the two stressors. Glutathione levels increased when exposed to high MP concentrations but decreased when co-exposed to Cd. Malondialdehyde content was only influenced by MPs and increased with elevated MPs. MPs or Cd alone did not increase protein carboxyl content but showed a synergistic effect and increased content. MPs or Cd alone showed no effect on lysozyme activity but had a synergistic effect and activated activity. Activities of both acid phosphatase and alkaline phosphatase were enhanced by MPs, Cd or their mixture, although there was an antagonistic interaction between the two stressors. In contrast, MPs, Cd or their mixture decreased complement 3 content, despite an antagonistic interaction between the two stressors. Collectively, this study suggests that exposure to Cd led to reduced Cd accumulation in the presence of MPs. Nevertheless, co-exposure could induce severe oxidative stress and stimulate innate immunity in the juvenile S. aequifasciatus.