Marine Sponge Species Research Articles

Temporal dynamics of the bacterial community structure and functions associated with marine sponges collected off Karah Island, Terengganu, Malaysia

The marine sponge microbiome has been investigated for decades, yet its temporal fluctuation/stability is poorly understood. This study aimed to describe the seasonal dynamics of the bacterial composition and predicted functions associated with two tropical marine sponge species (Aaptos suberitoides and Xestospongia testudinaria) collected off Karah Island, Malaysia, in the three seasons (dry season, pre- and post-monsoon season) using 16S rRNA gene amplicon sequencing and Functional Annotation of Prokaryotic Taxa (FAPROTAX). The bacterial taxonomic structures demonstrated divergences among A. suberitoides, X. testudinaria, and seawater, regardless of seasons. Chloroflexi, Proteobacteria, Cyanobacteria, Actinobacteriota, and Acidobacteriota comprised the core bacterial communities in two marine sponge species throughout the seasons, however, there were differences in bacterial composition between the two marine sponges. In addition, A. suberitoides was enriched with Dadabacteria, Spirochaetota, and Bdellovibrionota, whereas X. testudinaria abundantly harbored Poribacteria, PAUC34f, and Anck6. At the genus level, SAR202 clade and Candidatus Synechococcus spongiarum group dominated marine sponge samples throughout the year. Several genera, such as SAR202 clade, Candidatus Synechococcus spongiarum group, and Entotheonellaceae, were discovered only in marine sponge samples. Spirochaeta and Dadabacteriales displayed higher relative abundances in A. suberitoides, while Poribacteria and PAUC34f were more abundant in X. testudinaria. SAR202 clade was positively correlated with dissolved oxygen (DO), pH, phosphate, and ammonia in A. suberitoides. Likewise, Candidatus Synechococcus spongiarum group was negatively correlated with salinity and nitrate in X. testudinaria. Predicted functions by FAPROTAX annotated the phototrophic-related functions in both marine sponges, which might be attributed to a sponge-specific taxon Candidatus Synechococcus spongiarum group. The functions “predatory or exoparasitic” and “fermentation” were highly detected in A. suberitoides, which might be related to the bacterial genera Bdellovibrio and Spirochaeta, respectively. This study guides a deep understanding of the bacterial community structures associated with tropical marine sponges and their temporal behavior.

The marine sponge, Hymeniacidon sinapium, displays allorecognition of siblings during post-larval settling and metamorphosis to juveniles

Marine sponges, including the crumb of bread sponge, Hymeniacidon sinapium, display allorejection responses to contact with conspecifics in both experimental and natural settings. These responses have been used to infer immunocompetence in a variety of marine invertebrates. However, larvae and juveniles from several marine sponge species fuse and form chimeras. Some of these chimeras persist, whereas others eventually break down, revealing a period of allogeneic non-responsiveness that varies depending on the species. Alternatively, for H. sinapium, most pairs of sibling post-larvae and juveniles that settle in contact initiate immediate allorecognition and show the same morphological response progression as the adults. This indicates that allorecognition and response occurs during early metamorphosis. Results from H. sinapium and other sponge species, in addition to annotations of sponge genomes, suggest that allorecognition and immunocompetence in sponges are mediated by distinct systems and may become functional at different times during or after metamorphosis for different species. Consequently, allorecognition may not be a good proxy for the onset of immunocompetence.

The use of marine sponge species as a bioindicator to monitor metal pollution in Red Sea, Saudi Arabia

The existing data on trace elements of benthic sea organisms is scarce. Yet, the pressing issue of environmental contamination has spurred a surge in the use of organisms as biomonitors. In this study, sediment cores were sampled with the sponges, and metal concentrations were determined in both samples using ICP-MS. The mean concentrations of metals in benthic sediments and sponge species analyzed in this study differed significantly (Sediment >Phorbas species > Negombata magnifica > Callyspongia species > Amphimedon chloros). This could be due to the varying capacity of each sponge species to accumulate a particular metal by different means. Negombata magnifica and Phorbas species appear to be indicators, accumulators, or hyper-accumulators of Cu and Mn, while Callyspongia species is an indicator, accumulator, or hyper-accumulator of Cu only due to bioconcentration factor > 1 for the aforementioned metals. Concentrations of Cu and As in sediment were below the Effects Range Median but above the Effects Range Low threshold, hence the need to give more attention to these metals. This research provides a baseline dataset for designing monitoring strategies on this ecosystem and using sponge species for biomonitoring.

Marine sponges as bioindicators of pollution by synthetic microfibers in Antarctica

Different marine sponge species from Tethys Bay, Antarctica, were analyzed for contamination by polyester and polyamide microplastics (MPs). The PISA (Polymer Identification and Specific Analysis) procedure was adopted as it provides, through depolymerization and HPLC analysis, highly sensitive mass-based quantitative data. The study focused on three analytes resulting from the hydrolytic depolymerization of polyesters and polyamides: terephthalic acid (TPA), 6-aminohexanoic acid (AHA), and 1–6-hexanediamine (HMDA). TPA is a comonomer found in the polyesters poly(ethylene terephthalate) (PET) and poly(butylene adipate co terephthalate) (PBAT), and in polyamides such as poly(1,4-p-phenylene terephthalamide) (Kevlar™ and Twaron™ fibers) and poly(hexamethylene terephthalamide) (nylon 6 T). AHA is the monomer of nylon 6. HMDA is a comonomer of the aliphatic nylon 6,6 (HMDA-co-adipic acid) and of semi-aromatic polyamides such as, again, nylon 6 T (HMDA-co-TPA). Except for the biodegradable PBAT, these polymers exhibit high to extreme mechanical, thermal and chemical resistance. Indeed, they are used as technofibers in protective clothing able to withstand extreme conditions as those typical of Antarctica. Of the two amine monomers, only HMDA was found above the limit of quantification, and only in specimens of Haliclona (Rhizoniera) scotti, at a concentration equivalent to 27 μg/kg of nylon 6,6 in the fresh sponge. Comparatively higher concentrations, corresponding to 2.5–4.1 mg/kg of either PBAT or PPTA, were calculated from the concentration of TPA detected in all sponge species. Unexpectedly, TPA did not originate from PET (the most common textile fiber) as it was detected in the acid hydrolysate, whereas the PISA procedure results in effective PET depolymerization only under alkaline conditions. The obtained results showed that sponges, by capturing and concentrating MPs from large volumes of filtered marine waters, may be considered as effective indicators of the level and type of pollution by MPs and provide early warnings of increasing levels of pollution even in remote areas.

Microbiome species diversity and seasonal stability of two temperate marine sponges Hymeniacidon perlevis and Suberites massa

BackgroundMarine sponges are diverse and functionally important members of marine benthic systems, well known to harbour complex and abundant symbiotic microorganisms as part of their species-specific microbiome. Changes in the sponge microbiome have previously been observed in relation to natural environmental changes, including nutrient availability, temperature and light. With global climate change altering seasonal temperatures, this study aims to better understand the potential effects of natural seasonal fluctuations on the composition and functions of the sponge microbiome.ResultsMetataxonomic sequencing of two marine sponge species native to the U.K. (Hymeniacidon perlevis and Suberites massa) was performed at two different seasonal temperatures from the same estuary. A host-specific microbiome was observed in each species between both seasons. Detected diversity within S. massa was dominated by one family, Terasakiellaceae, with remaining dominant families also being detected in the associated seawater. H. perlevis demonstrated sponge specific bacterial families including aforementioned Terasakiellaceae as well as Sphingomonadaceae and Leptospiraceae with further sponge enriched families present.ConclusionsTo our knowledge, these results describe for the first time the microbial diversity of the temperate marine sponge species H. perlevis and S. massa using next generation sequencing. This analysis detected the presence of core sponge taxa identified in each sponge species was not changed by seasonal temperature alterations, however, there were shifts observed in overall community composition due to fluctuations in less abundant taxa, demonstrating that microbiome stability across seasons is likely to be host species specific.

Diversity and functional roles of the symbiotic microbiome associated to marine sponges off Karah Island, Terengganu, Malaysia

Marine sponges harbor a complex microbial consortium that plays important roles in host metabolisms and the production of chemical compounds. Symbiotic microbial community structures of marine sponges have been studied in recent years especially in the Caribbean and the Mediterranean Sea, whereas there is still a paucity of research in Malaysia. This study investigated the microbial community structures associated with four different marine sponge species (Aaptos suberitoides (Brøndsted, 1934), Neopetrosia exigua (Kirkpatrick, 1900), Theonella swinhoei (Gray, 1868), and Xestospongia testudinaria (Lamarck, 1815)) collected from Karah Island, Peninsular Malaysia. Microbial genomic DNA of four sponges and surrounding seawater were extracted and 16S rRNA gene amplicon sequencing was conducted targeting V3–V4 variable region using Illumina MiSeq platform. Paired-end sequences were analyzed using QIIME2 and the potential microbial functions related to the microbial communities of marine sponges and seawater were annotated using functional annotation of prokaryotic taxa (FAPROTAX). Microbial community structures and compositions were clearly different between sponges and seawater, as well as within different sponge species. Taxonomic analysis showed that Chloroflexi was the predominant phylum in all sponge species. Proteobacteria and Actinobacteriota were composing the core taxa of the microbial communities in N. exigua, T. swinhoei, and X. testudinaria, whereas Cyanobacteria and Proteobacteria were dominant in A. suberitoides. The functional analysis revealed that the abundance of the “predatory or exoparasitic” function was high in all sponges. The functions of aerobic ammonia oxidation and nitrification were dominant in marine sponges, rather than seawater. This study has important implications in understanding the microbial community structures associated with marine sponges in Malaysia, and gives fundamental information of sponge–microbe interactions and functional roles for future investigations.

Imidazole-Based Alkaloids from Marine Sponges (Leucetta and Clathrina) as Potential Inhibitors Targeting SARS-CoV-2 Main Protease: An In Silico Approach

Imidazole-based compounds form a prominent class of heterocyclic compounds, displaying diverse applications, especially with regards to its biological and pharmacological activities. Molecular docking, simulations, and drug-likeness prediction were performed on 45 imidazole-based alkaloids from two species of marine sponges (Leucetta and Clathrina). The study seeks to identify possible inhibitors of the SARS-CoV-2 Main Protease in an effort to battle the prevailing pandemic which has been caused by the widespread infections of the SAR-CoV-2 virus in its varied mutated forms. Computational analysis with MOE 2015.10 program reveals that, among the imidazole-based alkaloids, Naamidines have a high affinity for the target protein (PDB ID:6W63), even interacting with the catalytic dyad, as compared to its non-covalent inhibitor X77. Among all the top-scoring ligands, Naamidine H produced the highest binding score of −8.87078 kcal/mol. MD simulation studies with NAMD confirms the stability of the interactions of Naamidines with the target protein. MM-GBSA calculations were performed on the top binding ligands which further confirms the binding affinity of the top-scoring ligands. Computational and pharmacological investigations in this study proposes Naamidines, as effective inhibitors of Mpro. Naamidine I, Naamidine E, and Pyronaamidine could be potential anti-viral candidates against SAR-CoV-2.

Different Species of Marine Sponges Diverge in Osteogenic Potential When Therapeutically Applied as Natural Scaffolds for Bone Regeneration in Rats.

A highly porous structure, and an inorganic (biosilica) and collagen-like organic content (spongin) makes marine sponges potential candidates to be used as natural scaffolds in bone tissue engineering. The aim of this study was to characterize (through SEM, FTIR, EDS, XRD, pH, mass degradation and porosity tests) scaffolds produced from two species of marine sponges, Dragmacidon reticulatum (DR) and Amphimedon viridis (AV), and to evaluate the osteogenic potential of these scaffolds by using a bone defect model in rats. First, it was shown that the same chemical composition and porosity (84 ± 5% for DR and 90 ± 2% for AV) occurs among scaffolds from the two species. Higher material degradation was observed in the scaffolds of the DR group, with a greater loss of organic matter after incubation. Later, scaffolds from both species were surgically introduced in rat tibial defects, and histopathological analysis after 15 days showed the presence of neo-formed bone and osteoid tissue within the bone defect in DR, always around the silica spicules. In turn, AV exhibited a fibrous capsule around the lesion (19.9 ± 17.1%), no formation of bone tissue and only a small amount of osteoid tissue. The results showed that scaffolds manufactured from Dragmacidon reticulatum presented a more suitable structure for stimulation of osteoid tissue formation when compared to Amphimedon viridis marine sponge species.

Re-description of two marine sponge species (Demospongiae: Haplosclerida) from the coast of Karachi, Pakistan, Northern Arabian Sea

Re-description of two marine sponge species (Demospongiae: Haplosclerida) from the coast of Karachi, Pakistan, Northern Arabian Sea

Microbes from Mum: symbiont transmission in the tropical reef sponge Ianthella basta

Most marine sponge species harbour distinct communities of microorganisms which contribute to various aspects of their host’s health and physiology. In addition to their key roles in nutrient transformations and chemical defence, these symbiotic microbes can shape sponge phenotype by mediating important developmental stages and influencing the environmental tolerance of the host. However, the characterisation of each microbial taxon throughout a sponge’s life cycle remains challenging, with several sponge species hosting up to 3000 distinct microbial species. Ianthella basta, an abundant broadcast spawning species in the Indo-Pacific, is an emerging model for sponge symbiosis research as it harbours only three dominant symbionts: a Thaumarchaeotum, a Gammaproteobacterium, and an Alphaproteobacterium. Here, we successfully spawned Ianthella basta, characterised its mode of reproduction, and used 16S rRNA gene amplicon sequencing, fluorescence in situ hybridisation, and transmission electron microscopy to characterise the microbial community throughout its life cycle. We confirmed I. basta as being gonochoric and showed that the three dominant symbionts, which together make up >90% of the microbiome according to 16S rRNA gene abundance, are vertically transmitted from mother to offspring by a unique method involving encapsulation in the peri-oocytic space, suggesting an obligate relationship between these microbes and their host.

Targeted Isolation of Antibiotic Brominated Alkaloids from the Marine Sponge Pseudoceratina durissima Using Virtual Screening and Molecular Networking.

Many targeted natural product isolation approaches rely on the use of pre-existing bioactivity information to inform the strategy used for the isolation of new bioactive compounds. Bioactivity information can be available either in the form of prior assay data or via Structure Activity Relationship (SAR) information which can indicate a potential chemotype that exhibits a desired bioactivity. The work described herein utilizes a unique method of targeted isolation using structure-based virtual screening to identify potential antibacterial compounds active against MRSA within the marine sponge order Verongiida. This is coupled with molecular networking-guided, targeted isolation to provide a novel drug discovery procedure. A total of 12 previously reported bromotyrosine-derived alkaloids were isolated from the marine sponge species Pseudoceratina durissima, and the compound, (+)-aeroplysinin-1 (1) displayed activity against the MRSA pathogen (MIC: <32 µg/mL). The compounds (1–3, 6 and 9) were assessed for their central nervous system (CNS) interaction and behavioral toxicity to zebrafish (Danio rerio) larvae, whereby several of the compounds were shown to induce significant hyperactivity. Anthelmintic activity against the parasitic nematode Haemonchus contorutus was also evaluated (2–4, 6–8).

Marine sponges as coastal bioindicators of rare earth elements bioaccumulation in the French Mediterranean Sea

In recent years, the widespread use of rare earth elements (REEs) has raised the issue of their harmful effects on the aquatic environment. REEs are now considered as contaminants of emerging concern. Despite the increasing interest of REEs in modern industry, there is still a lack of knowledge on their potential impact on the environment and especially in the marine environment.In this context, the need for monitoring tools to assess REEs pollution status in marine ecosystems is considered as the first step towards their risk assessment. Similar to mussels, filter-feeder sponges have emerged as a key bio-monitor species for marine chemical pollution. Their key position at a low level of the trophic chain makes them suitable model organisms for the study of REEs potential transfer through the aquatic food web. We therefore undertook a comparative study on seven marine sponge species, assessing their capability to bioaccumulate REEs and to potentially transfer these contaminants to higher positions in the trophic chain. A spike experiment under controlled conditions was carried out and the intra- and inter-species variability of REEs was monitored in the sponge bodies by ICP-MS. Concentrations were found to be up to 170 times higher than the corresponding control specimens. The tubular species Aplysina cavernicola showed the highest concentrations among the studied species. This study shows, for the first time, the potential of marine sponges as bio-monitor of REEs as well as their possible application in the bioremediation of polluted sites.

Bnormal average increase in sea surface temperature may promote the first documented mortality event of a marine sponge in the Southeastern Brazil

Frequent heat waves and mass mortality events on marine biota are positively correlated to ocean warming. Although literature has indicated some species of marine sponges, and some oceanic regions, like the Brazilian Exclusive Economic Zone, may be less affected or seem to be more resilient under future scenarios of climate changes, few studies have focused on the species responses on the climate change issue along Brazilian coast. This paradigm was undone throughout 2019 after an exceptional average increase of 2 °C in the sea surface temperature (SST) and on precipitation values since 2015 at Ilha Grande Bay (IGB, SE Brazil). The combination of SST and precipitation average increase possibly favored an environmental context for the unprecedented strong population decline and mass mortality rate of the marine sponge species Desmapsamma anchorata in the austral spring. The species used to be one of the most frequent benthic species at IGB however it was only recorded in 41.7% sites (n = 12). From 162 individuals recorded at Abraãozinho along 180 m rocky shore, 83 individuals (51.2%) were healthy, 74 (45.7%) were intensively covered by cyanobacteria and locally bleached, and five (3.1%) were completely bleached or died. Desmapsamma anchorata population deterioration in a biogeographic transition zone (Rio de Janeiro state) may reflect a shift in the marine community of IGB, opening space for opportunistic species establishment and coverage increase, since IGB has a high species turnover. The three-dimensionality, the shelter for several species, the high competitive ability and the potential to indicate polluted or not polluted areas make D. anchorata a key species for IGB monitoring in a climate change scenario.

Biodiversity of the Indonesian marine sponge genus Aaptos with molecular networking approach

Many natural products have been isolated from the cryptic species of the Indonesian marine sponge. Despite this, it remains unclear how sponges produce such a diverse array of metabolites and their relationship to sponge diversity. During our expedition in 2017-2019, we collected the Indonesian marine sponge of the genus Aaptos, which was found surrounding Weh and Aceh Islands, the northwesternmost part of the Indonesian archipelago. All specimens were subjected to a feature-based molecular networking approach to understand their relationship. The molecular phylogenetic clades of genus Aaptos were examined by cytochrome oxide I (COI) while the presence of their chemotypes were confirmed by chemical analysis based on bioassay-guided separation with several steps of chromatography. As results, the presence Aaptos suberitoides, Aaptos aaptos, Aaptos nigra, Aaptos lobata, and Aaptos sp. were confirmed by the molecular phylogenetic. On the other hand, chemical analysis showed the presence of alkaloid-class molecules on all specimens. Interestingly, feature-based molecular networking revealed the whole figure of cryptic species were formed a clear and distinct group together with their chemotypes. Consequently, it confirmed that the relationship between the presence of each species as well as its chemotype can be distinguished clearly. In conclusion, we suspect the chemical analysis of the genus Aaptos have unknowingly conflated between different cryptic species, resulting in the seemingly idiosyncratic chemical variations.

Antibacterial activity of endosymbiotic fungi isolated from marine sponges collected from Kotok Kecil Island, Seribu Islands, Jakarta

Endosymbiont fungi from marine sponges are a rich source of medicinally active compounds. Indonesia has a huge number of marine sponges. This research was conducted to determine the antibacterial potential of endosymbiont fungi isolated from marine sponges collected from Kotok Kecil Island, Seribu Islands. The screening was conducted with two methods, the modified GIBEX and disc diffusion. Species of marine sponges were isolated, namely Petrosia sp., Stylissa carteri, Cinachyrella australiensis, Callyspongia sp., Petrosia nigrians, and Stylissa massa, and obtained 9 isolates of endosymbiont fungi. The GIBEX test against Escherichia coli and Streptococcus mutans showed that ethyl acetate extract had strongest antibacterial activity. Disc diffusion test of ethyl acetate extract, five isolates had antibacterial activity against S. mutans and four against E. coli. The isolate that showed the strongest antibacterial activity was from Petrosia sp. Which has an inhibition zone of 8.4 mm against E. coli and 7.45 mm against S. mutans. The main active compounds from the isolate of Petrosia sp. are butylhydroxytoluene and phthalic acid di-(2-propylpentyl) esters. Based on this study, we concluded that the endosymbiont fungi of marine sponges are potential to be developed for further development as source of antibacterial agents.

Total Phenolic Content (TPC), Total Flavonoid Content (TFC) and Antioxidants Activity of Marine Sponge Stylissa flabelliformis Ethanol Extract

Marine sponge Stylissa flabelliformis is a marine sponge species that is widely found in Indonesia. Marine sponges have been proven to have pharmacological activities including wound healing, cytotoxicity and antimicrobial activity. All these activities are related to its antioxidant potential. Antioxidants are important for human health due to its ability to protect cell damage caused by free radicals. The aim of this research was to study the antioxidant activity of marine sponge (Stylissa flabelliformis) and to observe the phytochemical compound of the marine sponge such as the phenolic and flavonoid content. Extraction was performed using cold maceration with 96% ethanol solvent and continued by rotary evaporator to get the concentrated extract. Antioxidants activity was analysed using DPPH (2,2-diphenyl-1-picrylhydrazyl) method, which examines the inhibitory concentration (IC50) of the ethanol extract. Total phenolic content (TPC) was examined using Gallic acid as the standard, while total flavonoid content (TFC) was examined using quercetin as the standard. The result showed a concentration-dependent antiradical activity by reduction of DPPH with an IC50 value 2000 µg/mL. Total phenolic content was 152,67 mg GAE/g, while the total flavonoid content was 155,79 mg QE/g.

An update on the diversity of marine sponges in the southern gulf of Mexico coral reefs.

Until now, 127 species of marine sponges have been recorded in the southern Gulf of Mexico (SGoM). In this study, we describe the sponge fauna recorded on 16 coral reefs of the SGoM, defined as the Mexican waters of the Gulf of Mexico (GoM), during a period from 2005 to 2019. We report 80 sponge species, including 34 first geographic records for the southern GoM region. The latter are fully described and illustrated, taking into account 24 that represent new records for the GoM: Agelas conifera, Agelas sventres, Agelas wiedenmayeri, Prosuberites carriebowensis, Desmanthus meandroides, Cliona aprica, Cliona dioryssa, Placospongia ruetzleri, Haliclona (Gellius) megasclera, Haliclona (Reniera) aff. portroyalensis, Neopetrosia proxima, Xestospongia arenosa, Calyx podatypa, Shiphonodictyon xamaycaense, Acarnus innominatus, Iotrochota arenosa, Polymastia tenax, Svenzea cristinae, Svenzea flava, Svenzea tubulosa, Svenzea zeai, Timea stenosclera, Stellettinopsis megastylifera, Suberea flavolivescens. The present work highlights the understimated and remarkable diversity of reef-associated sponges within the Campeche Bank Coral reef systems. Present work data was compiled with existing published information to produce an updated list of 161 known sponges in the southern GoM.

Microplastic distribution in urban vs pristine mangroves: Using marine sponges as bioindicators of environmental pollution

Sessile benthic organisms are considered good bioindicators for monitoring environmental quality of coastal ecosystems. However, these environments are impacted by new pollutants such as microplastics (MPs), where there is limited information about organisms that can be used as reliable bioindicators of these emerging contaminants. We evaluated MP concentrations in three compartments: surface sediment, water and in three marine sponge species (Haliclona implexiformis, Halichondria melanadocia and Amorphinopsis atlantica), to determine whether these organisms accumulate MPs and reflect their possible sources. Results showed MPs in all three compartments. Average concentrations ranged from 1861 to 3456 items kg−1 of dry weight in marine sponges, 130 to 287 items L−1 in water and 6 to 11 items kg−1 in sediment. The maximum MP concentration was in the sponge A. atlantica, which registered 5000 items kg−1 of dry weight, in water was 670 items L−1 and in sediment was 28 items kg−1, these values were found in the disturbed study area. The three sponge species exhibited MP bioaccumulation and showed significant differences between disturbed and pristine sites (F = 11.2, p < 0.05), suggesting their use as bioindicators of MP.

Seasonal Variation in Antimicrobial Activity of Crude Extracts of Psammaplysilla sp. 1 from Phillips Reef, South Africa.

Marine invertebrates constitute a diverse group of marine organisms beneficial to humanity due to their therapeutic significance. The marine sponge species Psammaplysilla sp. 1 was collected from Philips Reef, South Africa, over a four-season period and assayed for antimicrobial potential. The physicochemical parameters of the collection site were also recorded. The sponge crude extracts' antimicrobial activity was evaluated using an agar well diffusion assay against 5 pathogens. Phytochemical screening was conducted to identify the presence of 7 critical phytochemical groups. During the four seasons, the mean water temperature was 17.35°C ± 2.06, with autumn recording the highest (20°C) temperature. Antifungal activity was observed by Psammaplysilla sp. 1 (30 mm) against C. albicans, and this was higher than that showed by standard drugs ICZ-10 µg (15 ± 0.1 mm), FLU-15 µg (21 ± 0.2 mm), and VCZ-5 µg (17 ± 0.1 mm), respectively. Similar bioactivities were observed seasonally with Psammaplysilla sp. 1 (22 mm and 24 mm) during autumn and spring, respectively, against C. difficile while only crude extracts collected in spring showed bioactivity against C. albicans. Psammaplysilla sp. crude extracts showed broad-spectrum bioactivity against all test pathogens. DCM : ME crude extracts tested positive for the presence of 2/7 of the phytochemicals (terpenoids and flavonoids). GC-MS revealed several previously reported biologically active compounds such bicyclo[4.2.0]octa-1,3,5-trien-7-ol and phenol, 2,6-dibromo, some of which have been found in plants. This study revealed that sponge bioactivity is dependent on the season and further validated the antimicrobial potential of South African marine sponges.

Reproductive isolation between two cryptic sponge species in New Zealand: high levels of connectivity and clonality shape Tethya species boundaries

Although commonly reported among widespread marine taxa, hybridization has only been recorded for one species of marine sponge to date. Sponges have evolved an array of sexual and asexual reproductive strategies, but it remains unclear if the lack of reported hybrids in this phylum is due to their reproductive diversity (which promotes reproductive isolation) or instead due to a lack of data. In this study, we aimed to determine whether hybridization occurs between two cryptic species of Tethya burtoni (T. burtoni sp. A and T. burtoni sp. B) that live sympatrically in central New Zealand. We also examined how both small-scale population structure (for five locations) and asexual reproduction contributed to instances (or lack thereof) of hybridization for these sponges. Using 11 microsatellite markers, we found no evidence of hybridization between species. Both species exhibited differences in distribution, where one species was present at all five locations, but the other was only detected at three locations. For these three locations (all within 20 km of each other), both species exhibited high levels of gene flow. Asexual buds did not appear to disperse far, and groups of clonal individuals were found within areas of < 900 cm2. Asexual reproduction, therefore, did not play an obvious role in connectivity between populations, but instead appeared to be important for population maintenance. While specific mechanisms for reproductive isolation, such as gamete recognition, between both T. burtoni species remain unknown, we suggest that such mechanisms likely exist due to the strong differentiation found between both species (FST = 0.191, P < 0.0001). Further, the observed high levels of both gene flow and asexual reproduction may also act to reduce the potential for hybridization by maintaining genetic diversity and increasing the chance of mating with a conspecific individual.