Two centuries of sponges (phylum Porifera) taxonomic studies in Indonesia (1820-2021): checklist and bibliography.

Sponges in Indonesia have been studied since the 19th century during several historical expeditions and international collaborations. Hundreds of new species were reported from various locations, e.g., Ambon, Ternate, Sulawesi, Aru, and Kei Islands. This study aimed to create a sponge (Porifera: Calcarea, Demospongiae, Hexactinellida, and Homoscleromorpha) species checklist from Indonesia based on World Porifera Database. With a total of 731 species, our checklist comprises approximately 45 species of Calcarea, 566 species of Demospongiae, 115 species of Hexactinellida, and five species of Homoscleromorpha. The number of species are recorded from 12 marine ecoregions across the Indonesian Archipelago and freshwater habitats (Spongillida) between 1820-2021. The species composition indicates higher regional endemism or poorly studied since no other report after the original description. However, several marine ecoregions of Indonesia remain highly overlooked (e.g., Northeast Sulawesi, Papua, Southern Java, Western Sumatra), including freshwater habitats. Therefore, a taxonomic biodiversity baseline study, particularly on Porifera, is necessary to better understand the aquatic and marine biodiversity in the Indonesia Archipelago.

Xidaosterols A and B, two new steroids with unusual α-keto-enol functionality from the South China Sea sponge Neopetrosia chaliniformis.

Two new C29 steroids, xidaosterols A (1) and B (2), characterised by a common unusual α-keto-enol functionality bearing A-ring, together with three related known ones (3-5), were isolated from the South China Sea sponge Neopetrosia chaliniformis. Their structures were elucidated by extensive spectroscopic analyses and comparison with the spectral data reported in the literature, Xidaosterol B is an A-nor derivative of 1.

Mycale species of the tropical Indo-West Pacific (Porifera, Demospongiae, Poecilosclerida).

The species of the cosmopolitan sponge genus Mycale occurring in the tropical Indo-West Pacific region and adjacent subtropical waters are reviewed taxonomically. Specimens incorporated in the collections of the Naturalis Biodiversity Center form the basis of this comprehensive study, supplemented by (type) specimens borrowed from or examined in other institutions. Specimens available numbered 351, belonging to 44 species, including 14 species new to science, Mycale (Aegogropila) prognatha sp.nov., Mycale (Carmia) amiri sp.nov., Mycale (Carmia) fungiaphila sp.nov., Mycale (Carmia) monomicrosclera sp.nov., Mycale (Carmia) tenuichela sp.nov., Mycale (Carmia) tubiporicola sp.nov., Mycale (Carmia) tydemani sp.nov., Mycale (Mycale) asigmata sp.nov., Mycale (Mycale) grandoides sp.nov., Mycale (Mycale) sundaminorensis sp.nov., Mycale (Naviculina) mascarenensis sp.nov., Mycale (Paresperella) sceptroides sp.nov., Mycale (Paresperella) seychellensis sp.nov., Mycale (Zygomycale) sibogae sp.nov. Three species, indicated by the designation 'aff.', were not definitely assigned to known or new species due to uncertainty of their identity. The genus Kerasemna, previously considered a junior synonym of Mycale, was revived as an additional subgenus Mycale (Kerasemna). One species, previously assigned to the genus Desmacella as D. lampra De Laubenfels is here reassigned to Mycale, subgenus at present undecided. Additionally, species previously reported from the region but not represented in our collections are briefly characterized and discussed. We propose new names Mycale (Mycale) mauricei nom.nov. for Mycale macrochela Burton (junior primary homonym of Mycale fistulata var. macrochela Hentschel) and Mycale (Mycale) bouryesnaultae nom.nov. for Mycale (Mycale) fibrosa Boury-Esnault Van Beveren (junior primary homonym of Mycale (Aegogropila) adhaerens subsp. fibrosa Koltun). Keys to the species of each subgenus occurring in the region are provided. The opportunity of having studied this comprehensive set of species and specimens from the tropical Indo-West Pacific is taken to review and discuss the morphological and biogeographical data gathered so far on the genus Mycale. The genus currently comprises approximately 255 accepted species, with highest diversity focused in tropical Atlantic and Indo-West Pacific regions as well as in warm-temperate Mediterranean-Atlantic regions.

Bromopyrrole Alkaloids with the Inhibitory Effects against the Biofilm Formation of Gram Negative Bacteria.

Anti-biofilm assay guided fractionation of the marine sponge Stylissa massa revealed the butanol soluble fraction that was possessing the inhibitory activity toward the biofilm formation of bacterium E. coli. Chromatographic separation of the bioactive fraction resulted in the isolation of 32 bromopyrrole alkaloids, including six new alkaloids, named stylisines A-F (1-6). The structures of new alkaloids were established by comprehensive analyses of the two-dimensional (2D) NMR (COSY, HMQC, and HMBC) and the high resolution electrospray ionization mass spectroscopy (HRESIMS) data, while the absolute configurations were determined by the X-ray diffraction and the electronic circular dichroism (ECD) data. Bioassay results indicated that phakellin-based alkaloids, including dibromoisophakellin and dibromophakellin, significantly reduced the biofilm formation of the bacterium E. coli. Present work provided a group of new natural scaffolds for the inhibitory effects against the biofilm formation of E. coli.

Two Furanosesterterpenoids from the Sponge Luffariella variabilis.

Two new sesterterpenoids, 1 and 2, were isolated from the sponge Luffariella variabilis. Their planar structures were characterized with spectroscopic analyses. The sole chiral center of compound 1 was elucidated as 12R by comparing observed and calculated optical rotation values. The configurations of compound 2 were determined by NMR and electronic circular dichroism (ECD) studies. Furthermore, compound 2 showed cytotoxicity at IC50 1.0 µM against NBT-T2 cells.

Bottomless barrel-sponge species in the Indo-Pacific?

The use of nuclear markers, in addition to traditional mitochondrial markers, helps to clarify hidden patterns of genetic structure in natural populations (Palumbi & Baker, 1994). This is particularly evident among demosponges that possess slow mitochondrial evolutionary rates compared to Bilateria, where nuclear intron markers can aid in the understanding of shallow level phylogenetic relationships (Shearer et al., 2002). Ideally, these nuclear markers (i) are evolutionary well-conserved across different lineages, (ii) produce amplicons holding a number of sites with sufficient variability to answer the relevant phylogenetic question, (iii) derive from single copy genes (see review in Zhang & Hewitt, 2003). A popular method to amplify intron markers uses EPIC (Exon-Primed, Intron-Crossing) primers that anneal to the more conserved flanking exon regions and subsequently bridge the intron during amplification (Palumbi & Baker, 1994).

Sponges of the family Axinellidae (Porifera: Demospongiae) in Indonesia.

Nine species in five genera of the family Axinellidae, including three new species, Axinella badungensis sp. nov., A. balinensis sp. nov. and Phycopsis pesgalli sp. nov. are recorded from Indonesian waters within the limits of the Western Coral Triangle province. Descriptions and discussion of those species are presented here. Four new combinations, Phakettia arbora (Sim, Kim & Byeon, 1990) comb.nov., P. trachys (De Laubenfels, 1954) comb.nov., Echinoclathria retepora (Lendenfeld, 1887) comb.nov. and Amphimedon hispidula (Ridley, 1884) comb.nov. are also established here. The distributions of species previously described are here extended to the study area with the exception of Phakellia atypica which seems so far restricted to Indonesia.

Antibacterial bisabolane-type sesquiterpenoids from the sponge-derived fungus Aspergillus sp.

Four new bisabolane-type sesquiterpenoids, aspergiterpenoid A (1), (-)-sydonol (2), (-)-sydonic acid (3), and (-)-5-(hydroxymethyl)-2-(2',6',6'-trimethyltetrahydro-2H- pyran-2-yl)phenol (4) together with one known fungal metabolite (5) were isolated from the fermentation broth of a marine-derived fungus Aspergillus sp., which was isolated from the sponge Xestospongia testudinaria collected from the South China Sea. Four of them (1-4) are optically active compounds. Their structures and absolute configurations were elucidated by using NMR spectroscopic techniques and mass spectrometric analysis, and by comparing their optical rotations with those related known analogues. Compounds 1-5 showed selective antibacterial activity against eight bacterial strains with the MIC (minimum inhibiting concentrations) values between 1.25 and 20.0 µM. The cytotoxic, antifouling, and acetylcholinesterase inhibitory activities of these compounds were also examined.