Use of in vivo-induced antigen technology to identify bacterial genes expressed during solea senegalensis infection with Photobacterium damselae subsp. piscicida

The marine fish pathogen Photobacterium damselae subsp. piscicida (Phdp) is responsible for important outbreaks affecting several fish species including flatfish Solea senegalensis. The aim of this work was to identify in vivo-induced expressed immunogenic proteins using pooled sera from fish that have experienced photobacteriosis. In vivo induced immunogenic proteins included inosine-5'-monophosphate dehydrogenase (Impdh) and alkyl hydroperoxide reductase (AhpC), two proteins involved in peptide synthesis: serine hydroxymethyl transferase (Shmt) and alanyl-tRNA synthetase (AlaRS) and the non-ribosomal peptide synthetase involved in the synthesis of the siderophore piscibactin (Irp2)

Vaccination of Gilthead Seabream After Continuous Xenoestrogen Oral Exposure Enhances the Gut Endobolome and Immune Status via GPER1

In fish culture settings, the exogenous input of steroids is a matter of concern. Recently, we unveiled that in the gilthead seabream (Sparus aurata), the G protein-coupled estrogen receptor agonist G-1 (G1) and the endocrine disruptor 17α-ethinylestradiol (EE2) are potent modulators in polyreactive antibody production. However, the integral role of the microbiota upon immunity and antibody processing in response to the effect of EE2 remains largely unexplored. Here, juvenile seabreams continuously exposed for 84 days to oral G1 or EE2 mixed in the fish food were intraperitoneally (i.p.) immune primed on day 42 with the model antigen keyhole limpet hemocyanin (KLH). A critical panel of systemic and mucosal immune markers, serum VTG, and humoral, enzymatic, and bacteriolytic activities were recorded and correlated with gut bacterial metagenomic analysis 1 day post-priming (dpp). Besides, at 15 dpp, animals received a boost to investigate the possible generation of specific anti-KLH antibodies at the systemic and mucosal interphases by the end of the trial. On day 43, EE2 but not G1 induced a significant shift in the serum VTG level of naive fish. Simultaneously, significant changes in some immune enzymatic activities in the serum and gut mucus of the EE2-treated group were recorded. In comparison, the vaccine priming immunization resulted in an attenuated profile of most enzymatic activities in the same group. The gut genes qPCR analysis exhibited a related pattern, only emphasized by a significant shift in the EE2 group’s il1b expression. The gut bacterial microbiome status underwent 16S rRNA dynamic changes in alpha diversity indices, only with the exposure to oral G1, supporting functional alterations on cellular processes, signaling, and lipid metabolism in the microbiota. By the same token, the immunization elevated the relative abundance of Fusobacteria only in the control group, while this phylum was depleted in both the treated groups. Remarkably, the immunization also promoted changes in the bacterial class Betaproteobacteria and the estrogen-associated genus Novosphingobium. Furthermore, systemic and mucosal KLH-specific immunoglobulin (Ig)M and IgT levels in the fully vaccinated fish showed only slight changes 84 days post-estrogenic oral administration. In summary, our results highlight the intrinsic relationship among estrogens, their associated receptors, and immunization in the ubiquitous fish immune regulation and the subtle but significant crosstalk with the gut endobolome.Versión del edito

Effects on intestinal microbiota and immune genes of solea senegalensis after suspension of the administration of shewanella putrefaciens Pdp11

The interaction host-intestinal microbiota is essential for the immunological homeostasis of the host. Probiotics, prebiotics and synbiotics are promising tools for the manipulation of the intestinal microbiota towards beneficial effects to the host. The objective of this study was to evaluate the modulation effect on the intestinal microbiota and the transcription of genes involved in the immune response in head kidney of Solea senegalensis after administration of diet supplemented with the prebiotic alginate and the probiotic Shewanella putrefaciens Pdp11 CECT 7627 (SpPdp11). The results showed higher adaptability to dietary changes in the intestinal microbiota of fish fed diet with alginate and SpPdp11 together compared to those fish that received an alginate-supplemented diet. The alginate-supplemented diet produced up-regulation of genes encoding proteins involved in immunological responses, such as complement, lysozyme G and transferrin, and oxidative stress, such as NADPH oxidase and glutation peroxidase. On the other hand, the administration of alginate combined with SpPdp11 resulted in a significant increase of the transcription of genes encoding for glutation peroxidase and HSP70, indicating a potential protective effect of SpPdp11 against oxidative stress. In addition, these effects were maintained after the suspension of the probiotic treatment. The relationship between the modulation of the intestinal microbiota and the expression of genes with protective effect against the oxidative stress was demonstrated by the Principal Components Analysis.En prensa3,322