Structural insights and antimicrobial synergy of a proto-galectin from the marine sponge Aiolochroia crassa.

In this study, we isolated a novel lectin from the marine sponge Aiolochroia crassa, named AcrL. The lectin showed a preference for glycans containing sialic acid terminal residues, as indicated by the strongest inhibition with fetuin and bovine submaxillary mucin. Primary structure determination by mass spectrometry revealed that AcrL is a galectin with conserved amino acid residues typically involved in carbohydrate binding. Structural modeling indicated that AcrL adopts a typical galectin ß-sandwich motif, featuring two anti-parallel ß-sheets with five strands each. Docking calculations revealed a carbohydrate-binding site composed of a main site, capable of hosting galactopyranosides, and an extended site, facilitating the binding of complex carbohydrates. AcrL inhibited significant biofilm formation against Staphylococcus aureus, S. epidermidis, and Escherichia coli with concentrations ranging from 500 to 15.6 µg.mL-1 for S. aureus, 7.8 µg.mL-1 for S. epidermidis, and 500 µg.mL-1 for E. coli. Furthermore, when combined with different antibiotics, AcrL potentiated their effect against pathogenic bacteria. The antimicrobial mechanism of AcrL was investigated using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The analysis indicates that AcrL induces damage to the bacterial membrane. These findings underscore the discovery of a novel galectin in a basal organism and the comprehensive biochemical characterization conducted in this research, highlighting the potential of AcrL as a novel antibacterial agent and emphasizing its importance in combating bacterial infections.

Purification, biochemical characterization of a lectin from marine sponge Ircinia strobilina and its effect on the inhibition of bacterial biofilms.

A new lectin from marine sponge Ircinia strobilina, denominated IsL, was isolated by combination of affinity chromatography in Guar gum matrix followed by size exclusion chromatography. IsL was able to agglutinate native and enzymatically treated rabbit erythrocytes, being inhibited by galactosides, such as α-methyl-D-galactopyranoside, ß-methyl-D-galactopyranoside and α-lactose. IsL hemagglutinating activity was stable at neutral to alkaline pH, however the lectin loses its activity at 40° C. The molecular mass determinated by mass spectrometry was 13.655 ± 5 Da. Approximately 40% of the primary structure of IsL was determined by mass spectrometry, but no similarity was observed with any protein. The secondary structure of IsL consists of 28% α-helix, 26% ß-sheet, and 46% random region, as determined by dichroism circular. IsL was a calcium-dependent lectin, but no significant variations were observed by circular dichroism when IsL was incubated in presence of calcium and EDTA. IsL was not toxic against Artemia nauplii and did not have antimicrobial activity against bacterial cells. However, the IsL was able to significantly inhibit the biofilm formation of Staphylococcus aureus and Staphylococcus epidermidis.

New records of Neopetrosia carbonaria (Lamarck, 1814) from the Brazilian coast reveal new morphological features and spicule types.

Sponges of the family Petrosiidae have usually a stony and brittle texture due the high silica content of the mineral skeleton that is formed by a more-or-less regular isotropic reticulation of undefined primary and secondary tracts. Neopetrosia species are distributed worldwide and twelve species are found in the Tropical Western Atlantic Ocean, of which four are recorded from the Brazilian coast. Here, we describe new Neopetrosia carbonaria specimens from several localities along the NE Brazilian coast, analyze the Neopetrosia carbonaria holotype and review the previous record of N. carbonaria from the Brazilian coast. Our study reveals new morphological features and spicule types in the Brazilian populations of N. carbonaria. Now, Neopetrosia carbonaria is defined by a thick encrusting to repent or ramose sponge, with reddish brown to brown color or dark green to black color in vivo, two categories of oxeas as megascleres and raphidiform toxas as microscleres. These toxas are quite rare and occur in both black and brown sponges. Due the absence and rarity of raphidiform toxas in some specimens, unrelated to its color, we assume that these differences are intraspecific. However, we suggest that all records of Neopetrosia carbonaria should be reevaluated, since toxas can be easily overlooked, added to the use of molecular methods to investigate the relationship between the Caribbean and Brazilian populations.

Checklist, diversity descriptors and selected descriptions of a highly diverse intertidal sponge (Porifera) assemblage at Costa do Descobrimento (Bahia, Brazil).

Costa do Descobrimento is located in southern Bahia, Brazil, and only 22 species of sponges (Porifera) were known from the area until now, despite its important reef formations. In the present study, we report a checklist of the sponges of Costa do Descobrimento and their distribution in the studied reefs, with several species illustrated in life. We also describe nine new sponge records for this region, some of which are new records for Brazil, or new records of species previously only poorly known. We present alpha and beta diversity indices and compare the sponge assemblage of the sampled locations. Four reefs were considered: two fringing reefs (Arraial D'Ajuda-AA and Coroa Vermelha / Mutá-CVM) and two offshore Municipal Marine Park "Parque Municipal Marinho- (P.M.M. Coroa Alta-CA and P.M.M. Recife de Fora-RF). A total of 229 specimens were collected (224 Demospongiae, 2 Homoscleromorpha and 3 Calcarea). These were classified in 101 morphotypes. Studied materials included representatives of 15 orders, 34 families and 48 genera. The richest orders are Haplosclerida (29 spp.), Poecilosclerida (15 spp.) and Tetractinellida (11 spp.). The richest families were Chalinidae (24 spp.), Clionaidae (7 spp.) and Mycalidae and Suberitidae (6 spp. each). The richest genus is, by far, Haliclona (20 spp.). Only 13 species were shared among all four reefs surveyed, namely Amphimedon viridis, Cinachyrella alloclada, C. apion, Cladocroce caelum, Cliona varians, Dysidea robusta, Mycale (Naviculina) diversisigmata, Niphates erecta, Spirastrella hartmani, Tedania (Tedania) ignis, Terpios fugax, Tethya bitylastra and T. maza. The reefs with the highest richness were CA and CVM, and the lowest richness was observed in RF. The most similar reefs in terms of species composition were CA and CVM, while AA and RF were more dissimilar to the previous reefs, but also from each other. While the difference among CA, CVM and AA was mainly explained by species turnover, RF differed from the previous based on its lower richness (nestedness component). Even though CA and CVM were the richest reefs, AA presented the highest number of exclusive species, highlighting the uniqueness of this reef, and urging the inclusion of local beachrock fringing reefs in a more holistic conservation strategy at Costa do Descobrimento.

Two news species of Corallistidae (Porifera; Demospongiae; Tetractinellida) with a first record of Awhiowhio from the Atlantic.

In the present study, we describe two new species of Corallistidae from Brazil, comparing them to all valid species of the respective genera. Both are notable Porifera records, with the first specimen of Neophrissospongia Pisera and Lévi, 2002 registered for the Brazilian coast and the first specimen of Awhiowhio Kelly, 2007 registered for the Atlantic Ocean. The specimens were preserved in 80% ethanol and analyzed following classical procedure for Demospongiae, with dissociated spicule mounts, skeletal sections and Scanning Electron Microscopy. Neophrissospongia jorgeorum sp. nov. is differentiated from its congeners by the categories of spicules present, especially the lack of streptasters/amphiasters. Awhiowhio saci sp. nov. is characterized especially by the presence of spiraster-shaped microrhabds and microxeas.

A new species of Acarnus Gray, 1867 (Porifera, Demospongiae, Acarnidae) from NE Brazil.

The synapomorphic character of the genus Acarnus Gray, 1867 is the presence of the cladotylote spicule. Acarnus has 27 valid species worldwide, including five species reported from the Brazilian coast: A. innominatus Gray, 1867, A. nicoleae van Soest, Hooper & Hiemstra, 1991, A. souriei (Lévi, 1952), A. radovani (Boury-Esnault, 1973) and A. toxeata Boury-Esnault, 1973. Here we will describe A. microxeatus sp. nov., whose diagnosis is the presence of smooth microxeas and acanthoxeas, new characters for the genus. We also provide a complete characterization of the skeletal architecture and spicule morphology of A. toxeata, with scanning electron microscopy image (SEM) of the spicule set.

New lectin isolated from the tropical sponge Haliclona (Reniera) implexiformis (Hechtel, 1965) shows antibiofilm effect.

A lectin from the marine sponge Haliclona (Reniera) implexiformis (HiL) was isolated by affinity chromatography on Sepharose™ matrix. HiL showed specificity for galactose and its derivatives. The glycoproteins porcine stomach mucin (PSM) and bovine stomach mucin (BSM) were potent inhibitors. Hemagglutinating activity of the lectin was maximal between pH 5.0 and 9.0. The lectin remained active until 60°C. The presence of CaCl2 and EDTA did not affect the hemagglutinating activity. In SDS-PAGE, HiL showed a single band of 20 kDa under reduced conditions, whereas in the non-reducing conditions, it showed a band of 20 kDa and one additional band of 36 kDa. The average molecular mass determined by Electrospray Ionization Mass Spectrometry (ESI-MS) was 35.874 ± 2 Da in native and non-reducing conditions, whereas carboxyamidomethylated-lectin showed 18,111 Da. These data indicated that HiL consists in a dimer formed by identical subunits linked by disulfide bonds. Partial amino acid sequence of HiL was determined by mass spectrometry, and revealed that it is a new type of lectin, which showed no similarity with any protein. Secondary structure consisted of 6% α-helice, 31% ß-sheet, 18% ß-turn and 45% random coil. HiL showed significant reduction in the number of viable cells of Staphylococcus biofilms.

Lissodendoryx Topsent, 1892 (Poecilosclerida: Coelosphaeridae) from Brazil: a new species and transfer of Strongylacidon oxychaetum Menegola, Santos, Moraes & Muricy, 2012 to the genus Lissodendoryx.

The genus Lissodendoryx Topsent, 1892 has 118 valid species for the world, with five species records for Brazil. Here, we provide a description of Lissodendoryx (Waldoschmittia) almeidai sp. nov., distinguished from the other species of the subgenus by its spicular dimensions and spicular set, composed of oxeas as choanosomal megascleres, tylotes and arcuate isochelae. Also, we transfer Strongylacidon oxychaetum to Lissodendoryx (Anomodoryx), and record, for the first time, Lissodendoryx (Lissodendoryx) carolinensis from Brazil in addition to Lissodendoryx (Anomodoryx) vulcanus from Pernambuco State.

A new species of Desmacella Schmidt, 1870 (Porifera, Demospongiae, Desmacellidae) from the Northeast region of Brazil.

Desmacella is a Desmacellidae characterized by monactinal megascleres, arranged in plumose bundles; microscleres are sigmas and raphides; the latter may be absent (Hajud & Van Soest 2002). Thirty species are known worldwide, of which 19 occur in the Atlantic Ocean and three on the Brazilian coast: Desmacella annexa Schmidt, 1870; D. microsigmata, Cavalcanti, Santos & Pinheiro, 2015; D. tylovariabilis, Cavalcanti, Santos & Pinheiro, 2015 (de Voogd et al. 2022; Muricy 2022). In this paper, a new species of Desmacella from the Northeast region of Brazil is described. The material examined was compared with the descriptions and/or characterizations of all Desmacella species that occur in the Atlantic Ocean (Cavaltanti et al. 2015: 367-368). The specimen was preserved in ethanol 80% and is deposited in the Porifera Collection of the Natural History Museum of the Universidade Federal da Bahia.

Three new Raspailiidae Hentschel, 1923 (Axinellida, Demospongiae) from Peru.

Currently 26 sponge species are known for the Peruvian coast, but so far no raspailiids had been recorded from this region. Raspailiidae are distributed worldwide and its species are characterized by encrusting, massive, lobate, fan-shaped or branching growth forms, usually with a very hispid surface. In the present study, three new species of Raspailiidae are described from the Peruvian coast. Two new Eurypon spp. were collected at Islas Lobos de Afuera (Lambayeque). Eurypon lacertus sp. nov. is a thinly encrusting orange sponge with choanosomal skeleton composed of large tylostyles and small acanthostyles, and ectosomal skeleton with anisoxeas. Eurypon hookeri sp. nov. is a crustose, ruby red sponge, with choanosomal skeleton composed of large (subtylo)styles and acanthostyles, and ectosomal skeleton pierced by acanthostyles and (subtylo)styles, often surrounded by bouquets of smaller styles. The third new species, Plocamione matarani sp. nov., was collected at Matarani (Arequipa). It is a thinly encrusting orange sponge, the only Plocamione with two categories of choanosomal styles, and a single category of ectosomal styles, acanthostyles and anisoacanthostrongyles. These are the first records of Eurypon and Plocamione for the Peruvian coast, and the entire Southeastern Pacific, in the case of the latter.