The influence of Janthinobacterium sp. strain SLB01 on the cell culture of primmorphs of the sponge Lubomirskia baicalensis

Sponges (phylum Porifera) are ancient, multicellular metazoans. Freshwater sponges (Demosponges, Lubomirskiidae) dominate the fauna of the littoral zone of Lake Baikal. Over the last years, there have been mass diseases and death of endemic sponges. Previously, the strain Janthinobacterium sp. SLB01 was isolated from the diseased sponge Lubomirskia baicalensis. The studies of the pathogenicity of the strain Janthinobacterium sp. SLB01 for Baikal sponges has not been carried out, therefore we infected experimentally in vitro to determine its pathogenicity by the cell culture of the primmorphs with subsequent isolation, sequencing, and analysis of the genomes. The purpose of the study is to show that the strain Janthinobacterium sp. SLB01 isolated from the diseased sponge L. baicalensis is a pathogen for the cell culture of primmorphs. The bacteria from the infected samples were isolated and identified as strain Janthinobacterium sp. PLB02. A comparative analysis of the genomes of the strains showed that they are practically identical. The genomes of both strains contain genes vioABCDE violacein, flok formation, and strong biofilm, and the type VI secretion system (T6SS), as the primary virulence factor. These bacterial strains based on a comparison of complete genomes showed similarity with strain Janthinobacterium lividum MTR. Isolated strains of Janthinobacterium sp. are pathogens for cell cultures of primmorphs and L. baicalensis sponges. The results of the study will help to expand the understanding of microbial relationships in the development of disease and the death of Baikal sponges.

Genome Analysis of the Janthinobacterium sp. Strain SLB01 from the Diseased Sponge of the Lubomirskia baicalensis

The strain Janthinobacterium sp. SLB01 was isolated from the diseased freshwater sponge Lubomirskia baicalensis (Pallas, 1776) and the draft genome was published previously. The aim of this work is to analyze the genome of the Janthinobacterium sp. SLB01 to search for pathogenicity factors for Baikal sponges. We performed genomic analysis to determine virulence factors, comparing the genome of the strain SLB01 with genomes of other related J. lividum strains from the environment. The strain Janthinobacterium sp. SLB01 contained genes encoding violacein, alpha-amylases, phospholipases, chitinases, collagenases, hemolysin, and a type VI secretion system. In addition, the presence of conservative clusters of genes for the biosynthesis of secondary metabolites of tropodithietic acid and marinocine was found. We present genes for antibiotic resistance, including five genes encoding various lactamases and eight genes for penicillin-binding proteins, which are conserved in all analyzed strains. Major differences were found between the Janthinobacterium sp. SLB01 and J. lividum strains in the spectra of genes for glycosyltransferases and glycoside hydrolases, serine hydrolases, and trypsin-like peptidase, as well as some TonB-dependent siderophore receptors. Thus, the study of the analysis of the genome of the strain SLB01 allows us to conclude that the strain may be one of the pathogens of freshwater sponges.

Microbiome Changes of Endemic Lake Baikal Sponges during Bleaching Syndrome Development

The sponge (Porifera) microbiome is an indicator of both natural and anthropogenic stressors. Studying Baikal sponge microbial communities could help reveal if there is a connection between bacterial symbionts and a mass sponge bleaching event that was recently detected; 16S rRNA sequencing was performed among healthy and diseased freshwater sponges of Lubomirskia baikalensis and Baikalospongia intermedia, which were collected from Lake Baikal, Russia. A phylum-based taxonomic classification showed that Chlorophyta, Acidobacteria, Bacteroidetes, Actinobacteria and Cyanobacteria were most abundant across samples. When comparing healthy and diseased L. baikalensis samples, large variations in microbial composition were found at the phylum level. Comparative analyses, which were performed for the first time for B. intermedia, showed a decrease in Chlorophyta (unicellular green algae) and an increase in Bacteroidetes and Cyanobacteria in diseased specimens. At the genus level, the Opitutus (Verrucomicrobia), Planctomyces, and Nitrospira content increased in all diseased sponges, which reflected a general tendency toward an increase in Cyanobacteria in diseased sponges. Comparative analysis of the diseased and healthy sponge metagenomes showed that diseased sponges underwent various nonspecific changes in bacterial composition. The bacterial community composition is probably influenced by sponge type and degree of disease affection.

A checklist of halacarid and hydrachnid mites (Acari, Halacaridae & Hydrachnidia) associated with sponges (Porifera)

A compilation of halacarid and hydrachnid mite species found associated with sponges has been carried out based on published records. Altogether 78 halacarid mites species belonging to 15 genera viz. Agaue (9 species), Agauopsis (7 species), Arhodeoporus (1 species), Atelopsalis (1 species), Bradyagaue (1 species), Copidognathus (27 species), Halacarellus (7 species), Halacaropsis (2 species), Halacarus (5 species), Lohmannella (3 species), Maracarus (3 species), Rhombognathides (3 species), Rhombognathus (4 species), Spongihalacarus (1 species), and Thalassarachna (4 species) are reported. Twenty-four hydrachnid mite species belonging to three families viz. Hygrobatidae (2 species), Unionicolidae (20 species) and Pontarachnidae (2 species) are included. Some species of Unionicolidae are mentioned as possible sponge-mite species. Further studies, emphasizing developmental studies of unionicolid mites to get better ideas about associations with freshwater sponges are needed. Molecular sequencing will reveal more cryptic species and improve the quality of re-descriptions of currently recognized species in these sponge associated mites.

Zunielmis pax, a new genus and species of riffle beetles (Coleoptera: ­Elmidae) from Colombia

A new riffle beetle, Zunielmis pax gen. et sp. nov., is described from Colombia (Vichada, Puerto Carreño, Bita River basin). It can be distinguished from all the other elmids by having large areas of a microgranular mesh (plastron) on the pronotum and elytra, crenulate lateral margin of the latter two, the shorter interocular distance than diameter of each eye, as well as by the characters of the structure of mandibles, the shape and sculpture of pronotum, and the structure of mesosternum, mesotibiae and elytra. The imagoes were collected on freshwater sponges. The habitat, where the new species was found, is described, and the adaptive meaning of the characteristics of plastron are discussed. Drawings and photographs of the adult habitus, distinctive morphological characters, and male and female genitalia are provided.

Relationship between bacterial phylotype and specialized metabolite production in the culturable microbiome of two freshwater sponges

Microbial drug discovery programs rely heavily on accessing bacterial diversity from the environment to acquire new specialized metabolite (SM) lead compounds for the therapeutic pipeline. Therefore, knowledge of how certain bacterial taxa are distributed in nature, in addition to the degree of variation of SM production within those taxa, is critical to informing these front-end discovery efforts and making the overall sample collection and bacterial library creation process more efficient. In the current study we employed MALDI-TOF mass spectrometry and the bioinformatics pipeline IDBac to analyze diversity within phylotype groupings and SM profiles of hundreds of bacterial isolates from two Eunapius fragilis freshwater sponges, collected 1.5 km apart. We demonstrated that within two sponge samples of the same species, the culturable bacterial populations contained significant overlap in approximate genus-level phylotypes but mostly non-overlapping populations of isolates when grouped lower than the level of genus. Further, correlations between bacterial phylotype and SM production varied at the species level and below, suggesting SM distribution within bacterial taxa must be analyzed on a case-by-case basis. Our results suggest that two E. fragilis freshwater sponges collected in similar environments can exhibit large culturable diversity on a species-level scale, thus researchers should scrutinize the isolates with analyses that take both phylogeny and SM production into account in order to optimize the chemical space entering into a downstream bacterial library.

Discovery of the freshwater sponge genus Corvospongilla Annandale (Porifera: Spongillida) in Australia with the description of a new species and phylogeographic implications

A recent discovery of freshwater sponges in an unexplored hydrographic basin in north-western Australia provided the opportunity to investigate the genus Corvospongilla Annandale (Spongillida: Spongillidae) using integrative systematics. Emendation of the genus diagnosis is provided. A comparative analysis of a Corvospongilla global dataset of morphological traits together with biogeographic patterns disclosed a new Australasian Corvospongilla species and along with molecular analyses provided the basis for a phylogenetic and phylogeographic tree for some Asian, Afrotropical and Australasian lineages.