Cultures of the Marine Bacterium Pseudovibrio denitrificans Ab134 Produce Bromotyrosine-Derived Alkaloids Previously Only Isolated from Marine Sponges.

Herein we report the isolation and spectroscopic identification of fistularin-3 (1), 11-hydroxyaerothionin (2), and verongidoic acid (3), as well as the UPLC-HRMS detection of aerothionin (4), homopurpuroceratic acid B (5), purealidin L (6), and aplysinamisine II (7), from cultures of the marine bacterium Pseudovibrio denitrificans Ab134, isolated from tissues of the marine sponge Arenosclera brasiliensis. These results unambiguously demonstrate for the first time that bromotyrosine-derived alkaloids that were previously isolated only from Verongida sponges can be biosynthesized by a marine bacterium.

Environmental conditions affect activity and associated microorganisms of marine sponges.

Changes in environmental conditions can influence sponges and their holobionts. The present study investigated the effect of upwelling and anthropogenic pollution on the bioactivity of marine sponges, microbial communities and functional genes, and composition of their chemical compounds. The species Dysidea etheria, Darwinella sp., Hymeniacidon heliophila and Tedania ignis were collected from areas with distinct influence of upwelling and low anthropogenic impact and from areas without influence of upwelling but affected by sewage and the port. In most cases, the same sponge species collected from areas with distinct environmental conditions had a different chemical composition, antifouling activity, composition and diversity of associated microorganisms. Antimicrobial, quorum sensing inhibitory and anti-larval activities of sponge extracts were more pronounced in the area without upwelling showing higher level of anthropogenic pollution. This study suggests that upwelling and anthropogenic pollution affect the chemical activity and holobiome composition of sponges.

Distribution and Classification of Serine ß-Lactamases in Brazilian Hospital Sewage and Other Environmental Metagenomes Deposited in Public Databases.

ß-lactam is the most used antibiotic class in the clinical area and it acts on blocking the bacteria cell wall synthesis, causing cell death. However, some bacteria have evolved resistance to these antibiotics mainly due the production of enzymes known as ß-lactamases. Hospital sewage is an important source of dispersion of multidrug-resistant bacteria in rivers and oceans. In this work, we used next-generation DNA sequencing to explore the diversity and dissemination of serine ß-lactamases in two hospital sewage from Rio de Janeiro, Brazil (South Zone, SZ and North Zone, NZ), presenting different profiles, and to compare them with public environmental data available. Also, we propose a Hidden-Markov-Model approach to screen potential serine ß-lactamases genes (in public environments samples and generated hospital sewage data), exploring its evolutionary relationships. Due to the high variability in ß-lactamases, we used a position-specific scoring matrix search method (RPS-BLAST) against conserved domain database profiles (CDD, Pfam, and COG) followed by visual inspection to detect conserved motifs, to increase the reliability of the results and remove possible false positives. We were able to identify novel ß-lactamases from Brazilian hospital sewage and to estimate relative abundance of its types. The highest relative abundance found in SZ was the Class A (50%), while Class D is predominant in NZ (55%). CfxA (65%) and ACC (47%) types were the most abundant genes detected in SZ, while in NZ the most frequent were OXA-10 (32%), CfxA (28%), ACC (21%), CEPA (20%), and FOX (19%). Phylogenetic analysis revealed ß-lactamases from Brazilian hospital sewage grouped in the same clade and close to sequences belonging to Firmicutes and Bacteroidetes groups, but distant from potential ß-lactamases screened from public environmental data, that grouped closer to ß-lactamases of Proteobacteria. Our results demonstrated that HMM-based approach identified homologs of serine ß-lactamases, indicating the specificity and high sensitivity of this approach in large datasets, contributing for the identification and classification of a large number of homologous genes, comprising possible new ones. Phylogenetic analysis revealed the potential reservoir of ß-lactam resistance genes in the environment, contributing to understanding the evolution and dissemination of these genes.

Sub-clinical infection as an effective protocol for obtaining anti-Leishmania chagasi amastigote antibodies of different animal species.

This work aims at identifying an effective protocol to raise anti-Leishmania chagasi amastigote antibodies in different animal species. Protocols of immunization by subcutaneous injections of L. chagasi promastigote and amastigote lysates or by either intravenous or subcutaneous inoculation of live metacyclic promastigotes were assessed in mice, rabbits, and dogs. The immunization with live promastigotes produced a strong humoral immune response against L. chagasi amastigotes in all three animal species. The sera from animals immunized with the promastigote lysate did not react with amastigotes and, conversely, the sera from mice immunized with the amastigote lysate did not react with promastigotes. Taken all data together, the immunization through infection with metacyclic promastigotes was considered the most satisfactory way to immunize animals for obtaining anti-amastigote and anti-promastigote antibodies, since it did not only allowed the obtention of antibody against the two forms of the parasite, but it is also cheap, less laborious than carrying out the purification of amastigotes from infected tissues and avoid the use of a large number of hamsters for obtention the amastigotes, necessary to produce the immunogenic lysates. Furthermore, this immunization protocol was comparable to the amastigote lysate immunization protocol for the obtaining of mouse monoclonal antibodies (mAbs).

Photobacterium sanctipauli sp. nov. isolated from bleached Madracis decactis (Scleractinia) in the St Peter & St Paul Archipelago, Mid-Atlantic Ridge, Brazil.

Five novel strains of Photobacterium (A-394T, A-373, A-379, A-397 and A-398) were isolated from bleached coral Madracis decactis (scleractinian) in the remote St Peter & St Archipelago (SPSPA), Mid-Atlantic Ridge, Brazil. Healthy M. decactis specimens were also surveyed, but no strains were related to them. The novel isolates formed a distinct lineage based on the 16S rRNA, recA, and rpoA gene sequences analysis. Their closest phylogenetic neighbours were Photobacterium rosenbergii, P. gaetbulicola, and P. lutimaris, sharing 96.6 to 95.8% 16S rRNA gene sequence similarity. The novel species can be differentiated from the closest neighbours by several phenotypic and chemotaxonomic markers. It grows at pH 11, produces tryptophane deaminase, presents the fatty acid C18:0, but lacks C16:0 iso. The whole cell protein profile, based in MALDI-TOF MS, distinguished the strains of the novel species among each other and from the closest neighbors. In addition, we are releasing the whole genome sequence of the type strain. The name Photobacterium sanctipauli sp. nov. is proposed for this taxon. The G + C content of the type strain A-394(T) (= LMG27910(T) = CAIM1892(T)) is 48.2 mol%.