Microbiome analysis of healthy and diseased sponges Lubomirskia baicalensis by using cell cultures of primmorphs

Abstract

Endemic sponges (Demosponges, Lubomirskiidae) dominate the fauna of the littoral zone of Lake Baikal. These freshwater sponges live in symbiosis with diverse eukaryotes and prokaryotes, including chlorophyll-containing microalgae. Within the last 5 years, the incidence of sponge disease and mortality events in Lake Baikal has increased. The etiology and ecology of these events remain unknown, in part because of the lack of models to study sponge-microbe interactions. In this work, we tested the use of primmorph cell cultures of Lubomirskia baicalensis as a tool for investigating the microbiomes of sponges. We infected primmorphs, cultured in vitro, with samples from diseased sponges and observed, by microscopy, disease symptoms, including loss of green symbionts, associated with mass die-off events. Subsequent sequencing of 16S rRNA gene fragments revealed that the microbiome community of healthy sponge and primmorphs formed a group separate from the community of diseased sponges and infected primmorphs. This confirms the suitability of the primmorph cell culture as a model sponge system. We also discovered mass mortality of green symbionts (Chlorophyta) was associated with a shift in the microbial communities of sponges/primmorphs. Microbes in diseased sponges, and infected primmorphs, belonged mainly to the phyla Bacteroidetes and Proteobacteria and these families Flavobacteriaceae, Burkholderiaceae, and Moraxellaceae. Primmorphs cell culture may provide a model to study interactions between these bacteria and their host and elucidate the cause of mass mortality events.

Genome Analysis of Two Bacterial Strains Isolated from Diseased Freshwater Sponge Reveals the Probable Cause of Its Joint Domination in Microbial Community

“…SLB02 (as many of Bacteroidetes) have specific polysaccharide utilization loci (PULs) to digest the wide range of them. We observe the joint domination of these two strains into diseased sponges and the infected primmorphs[7,13].Bacteria of Janthinobacterium sp. SLB01 colonizes the space and suppress the other bacteria (especially Gram-positive) with violacein: pigment production we observed in cell culture (Figure 4)and all required genes (operon VioABCDE) are present into its genome.…”

“…Among these, the families Flavobacteriaceae and Oxalobacteraceae were dominant. Further we observed the increase in relative abundance of Flavobacteriaceae and Oxalobacteraceae in the diseased sponges and the infected cell cultures of primmorphs [7,13], isolated and cultivated separately and performed whole genome sequencing two dominating strains named Janthinobacterium sp. SLB01 and Flavobacterium sp.…”

“…They cover up to 50% of the available surfaces [1] and represent a complex consortium of many species of eukaryotes and prokaryotes, including diverse chlorophyll-containing microalgae [2][3][4]. The first appearance of anomalously pink-colored L. baicalensis (Pallas, 1776) sponges was In previous studies we reported a shift in microbial communities of the diseased Baikal sponges characterized by mass mortality of green symbionts (Chlorophyta) and increased abundances of several different opportunistic colonizers [7,13]. Microbes in diseased sponges belonged mainly to the phyla Bacteroidetes and Proteobacteria and were much more diverse at the family level.…”

Exposure to environmentally relevant oxytetracycline induced gut histopathological damages and microbiota alterations of Pelophylax nigromaculatus larvae

“…For example, the significant increase in Fusobacteria and Dependentiae in OTC treatment groups may prefigure the enhancement of their resistance. Moreover, Fusobacteria has been shown to be a harmful bacteria associated with colorectal cancer and intestinal diseases, while Dependentiae was the common pathogenic bacteria in aquatic ecosystems (Chernogor et al, 2020; Park et al, 2016). Thus, we consider these changes of bacteria at phylum level induced by OTC would exert adverse effect on tadpole's health.…”

Bioinformatics Applications to Reveal Molecular Mechanisms of Gene Expression Regulation in Model Organisms

“…The authors described a possible mechanism of the joint occupation of the ecological niche in the freshwater sponge microbial community. This study broadened our understanding of the symbiotic relationship between microorganisms and freshwater sponges in Lake Baikal [ 24 ].…”