Phylogeny of Tetillidae (Porifera, Demospongiae, Spirophorida) based on three molecular markers

Using nanotechnology to progress the utilization of marine natural products in combating multidrug resistance in cancer: A prospective strategy

Achieving targeted, customized, and combination therapies with clarity of the involved molecular pathways is crucial in the treatment as well as overcoming multidrug resistance (MDR) in cancer. Nanotechnology has emerged as an innovative and promising approach to address the problem of drug resistance. Developing nano-formulation-based therapies using therapeutic agents poses a synergistic effect to overcome MDR in cancer. In this review, we aimed to highlight the important pathways involved in the progression of MDR in cancer mediated through nanotechnology-based approaches that have been employed to circumvent them in recent years. Here, we also discussed the potential use of marine metabolites to treat MDR in cancer, utilizing active drug-targeting nanomedicine-based techniques to enhance selective drug accumulation in cancer cells. The discussion also provides future insights for developing complex targeted, multistage responsive nanomedical drug delivery systems for effective cancer treatments. We propose more combinational studies and their validation for the possible marine-based nanoformulations for future development.

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.

Anti-inflammatory, anti-infectious and anti-cancer potential of marine algae and sponge: A review

Marine organisms are potentially a pretty good source of highly bioactive secondary metabolites that are best known for their anti-inflammation, anti-infection, and anti-cancer potential. The growing threat of bacterial resistance to synthetic antibiotics, is a potential source to screen terrestrial and marine natural organisms to discover promising anti-inflammatory and antimicrobial agents which can synergistically overcome the inflammatory and infectious disases. Algae and sponge have been studied enormously to evaluate their medicinal potential to fix variety of diseases, especially inflammation, infections, cancers, and diabetes. Cytarabine is the first isolated biomolecule from marine organism which was successfully practiced in clinical setup as chemotherapeutic agent against xylogenous leukemia both in acute and chronic conditions. This discovery opened the horizon for systematic evaluation of broad range of human disorders. This review is designed to look into the literature reported on anti-inflammatory, anti-infectious, and anti-cancerous potential of algae and sponge to refine the isolated compounds for value addition process.

Population structure and microbial community diversity of two common tetillid sponges in a tropical reef lagoon

Sponges are predicted to dominate future reef ecosystems influenced by anthropogenic stressors and global climate change. The ecological success of sponges is attributed to their complex physiology, which is in part due to the diversity of their associated prokaryotic microbiome. However, the lack of information on the microbial community of many sponge species makes it difficult to gauge their interactions and functional contributions to the ecosystem. Here, we investigated the population dynamics and microbial community composition of two tetillid sponges identified as Cinachyrella sp. and Paratetilla sp., which are common on coral bommies in a reef lagoon in Bolinao, northwestern Philippines. The sponges ranged in size from 2.75 ± 2.11 to 6.33 ± 3.98 cm (mean ± standard deviation) and were found at an average density of 1.57 ± 0.79 to 4.46 ± 3.60 individuals per sq. m. on the bommies. The tetillid sponge population structure remained stable over the course of four years of monitoring. Prokaryotic communities associated with the sponges were distinct but had overlapping functions based on PICRUSt2 predictions. This convergence of functions may reflect enrichment of metabolic processes that are crucial for the survival of the tetillid sponges under prevailing conditions in the reef lagoon. Differentially enriched functions related to carbon, sulfur, fatty acid, and amino acid metabolism, cellular defense, and stress response, may influence the interactions of tetillid sponges with other biota on the bommies.

Natural products against cancer: Review on phytochemicals from marine sources in preventing cancer

Marine natural products have as of now been acknowledged as the most important source of bioactive substances and drug leads. Marine flora and fauna, such as algae, bacteria, sponges, fungi, seaweeds, corals, diatoms, ascidian etc. are important resources from oceans, accounting for more than 90% of the total oceanic biomass. They are taxonomically different with huge productive and are pharmacologically active novel chemical signatures and bid a tremendous opportunity for discovery of new anti-cancer molecules. The water bodies a rich source of potent molecules which improve existence suitability and serve as chemical shield against microbes and little or huge creatures. These molecules have exhibited a range of biological properties antioxidant, antibacterial, antitumour etc. In spite of huge resources enriched with exciting chemicals, the marine floras and faunas are largely unexplored for their anticancer properties. In recent past, numerous marine anticancer compounds have been isolated, characterized, identified and are under trials for human use. In this write up we have tried to compile about marine-derived compounds anticancer biological activities of diverse flora and fauna and their underlying mechanisms and the generous raise in these compounds examined for malignant growth treatment in the course of the most recent quite a long while.

Unravelling the moons: review of the genera Paratetilla and Cinachyrella in the Indo-Pacific (Demospongiae, Tetractinellida, Tetillidae)

Paratetillabacca(Selenka, 1867) andCinachyrellaaustraliensis(Carter, 1886) occur in a broad range of marine environments and are allegedly widely distributed species in the Indo-Pacific. We coin the term ‘moon sponges’ for these species as they are spherical in shape with numerous porocalices resembling the lunar surface. Both species have a complex taxonomic history with high synonymization, in particular by Burton (1934, 1959). An examination of the junior synonyms proposed by Burton (1934, 1959) was conducted to establish the validity of the names. More than 230 specimens from Naturalis Biodiversity Center were reviewed that belong to the generaParatetillaandCinachyrellafrom marine lakes, coral reefs, and mangroves in Indonesia. The aim of the current study was to untangle the taxonomic history, describe the collection of moon sponges from Indonesia, and develop a key. We extensively reviewed the taxonomic literature as well as holotypes of most of the species synonymized by Burton. The taxonomic history ofParatetillaspp. andCinachyrellaaustraliensisshowed some cases of misinterpreted synonyms, misidentifications, and lack of detailed descriptions for some species. The conclusion of the revision is that there are three valid species ofParatetilla(P.arcifera,P.bacca, andP.corrugata) and four valid species ofCinachyrella(C.australiensis,C.porosa,C.paterifera, andC.schulzei) in Indonesia. This is furthermore corroborated by molecular work from previous studies.ParatetillaarciferaWilson 1925 andC.porosa(Lendenfeld, 1888) are resurrected. A full review of taxonomic history is provided as well as a key for identification of moon sponges from Indonesia. All species are sympatric and we expect that there are undescribed species remaining within the Tetillidae from the Indo-Pacific. Our current review provides the framework from which to describe new species in the generaParatetillaandCinachyrellafrom the Indo-Pacific.

Unravelling the moons: review of the genera Paratetilla and Cinachyrella in the Indo-Pacific (Demospongiae, Tetractinellida, Tetillidae)

Paratetillabacca (Selenka, 1867) and Cinachyrellaaustraliensis (Carter, 1886) occur in a broad range of marine environments and are allegedly widely distributed species in the Indo-Pacific. We coin the term ‘moon sponges’ for these species as they are spherical in shape with numerous porocalices resembling the lunar surface. Both species have a complex taxonomic history with high synonymization, in particular by Burton (1934, 1959). An examination of the junior synonyms proposed by Burton (1934, 1959) was conducted to establish the validity of the names. More than 230 specimens from Naturalis Biodiversity Center were reviewed that belong to the genera Paratetilla and Cinachyrella from marine lakes, coral reefs, and mangroves in Indonesia. The aim of the current study was to untangle the taxonomic history, describe the collection of moon sponges from Indonesia, and develop a key. We extensively reviewed the taxonomic literature as well as holotypes of most of the species synonymized by Burton. The taxonomic history of Paratetilla spp. and Cinachyrellaaustraliensis showed some cases of misinterpreted synonyms, misidentifications, and lack of detailed descriptions for some species. The conclusion of the revision is that there are three valid species of Paratetilla (P.arcifera, P.bacca, and P.corrugata) and four valid species of Cinachyrella (C.australiensis, C.porosa, C.paterifera, and C.schulzei) in Indonesia. This is furthermore corroborated by molecular work from previous studies. ParatetillaarciferaWilson 1925 and C.porosa (Lendenfeld, 1888) are resurrected. A full review of taxonomic history is provided as well as a key for identification of moon sponges from Indonesia. All species are sympatric and we expect that there are undescribed species remaining within the Tetillidae from the Indo-Pacific. Our current review provides the framework from which to describe new species in the genera Paratetilla and Cinachyrella from the Indo-Pacific.

Divergence times in demosponges (Porifera): first insights from new mitogenomes and the inclusion of fossils in a birth-death clock model

BACKGROUND

Approximately 80% of all described extant sponge species belong to the class Demospongiae. Yet, despite their diversity and importance, accurate divergence times are still unknown for most demosponge clades. The estimation of demosponge divergence time is key to answering fundamental questions on the origin of Demospongiae, their diversification and historical biogeography. Molecular sequence data alone is not informative on an absolute time scale, and therefore needs to be "calibrated" with additional data such as fossils. Here, we calibrate the molecular data with the fossilized birth-death model, which compared to strict node dating, allows for the inclusion of young and old fossils in the analysis of divergence time. We use desma-bearing sponges, a diverse group of demosponges that form rigid skeletons and have a rich and continuous fossil record dating back to the Cambrian (~500 Ma), to date the demosponge radiation and constrain the timing of key evolutionary events, like the transition from marine to freshwater habitats. To infer a dated phylogeny of Demospongiae we assembled the mitochondrial genomes of six desma-bearing demosponges from reduced-representation genomic libraries. The total dataset included 33 complete demosponge mitochondrial genomes and 30 fossils.

RESULTS

Our study supports a Neoproterozoic origin of Demospongiae. Novel age estimates for the split of freshwater and marine sponges dating back to the Carboniferous and the previously assumed recent (~18 Ma) diversification of freshwater sponges is supported. Moreover, we provide detailed age estimates for a possible diversification of Tetractinellidae (~315 Ma), the Astrophorina (~240 Ma), the Spirophorina (~120 Ma) and the family Corallistidae (~188 Ma) all of which are considered as key groups for dating the Demospongiae due to their extraordinary rich and continuous fossil history.

CONCLUSION

This study provides novel insights into the evolution of Demospongiae. Observed discrepancies of our dated phylogeny with their putative first fossil appearance dates are discussed for selected sponge groups. For instance, a Carboniferous origin of the order Tetractinellida seems to be too late, compared to their first appearance in the fossil record in the Middle Cambrian. This would imply that Paleozoic spicule forms are not homologous to post-Paleozoic forms.

Molecular diversity of benthic ctenophores (Coeloplanidae)

Coeloplanidae, the largest family of benthic ctenophores, comprises 33 species, all described based on traditional morphological characteristics, such as coloration, length, and number of aboral papillae, which are highly variable and can be affected by fixation methods and environmental conditions. Thus, there is a need for reliable genetic markers to complement the morphological identifications at the species level. Here, we analyzed 95 specimens from 11 morphologically distinct species of benthic ctenophores from the Red Sea and Sulu Sea, and tested selected regions of four genetic markers (ITS1, 18S rRNA, 28S rRNA and COI) for their ability to differentiate between species. We show that the barcoding region of the mitochondrial gene, cytochrome oxidase subunit I (COI), is highly variable among species of Coeloplanidae, and effectively discriminates between species in this family. The average Kimura-2-parameter (K2P) distance between species-level clades was 10%, while intraspecific variation was ~30 times lower (0.36%). COI-based phylogeny supported the delineation of four recently described new species from the Red Sea. The other nuclear markers tested were found to be too conserved in order to separate between species. We conclude that COI is a potential molecular barcode for the family Coeloplanidae and suggest to test it in pelagic ctenophores.

Evolution of group I introns in Porifera: new evidence for intron mobility and implications for DNA barcoding

BACKGROUND

Mitochondrial introns intermit coding regions of genes and feature characteristic secondary structures and splicing mechanisms. In metazoans, mitochondrial introns have only been detected in sponges, cnidarians, placozoans and one annelid species. Within demosponges, group I and group II introns are present in six families. Based on different insertion sites within the cox1 gene and secondary structures, four types of group I and two types of group II introns are known, which can harbor up to three encoding homing endonuclease genes (HEG) of the LAGLIDADG family (group I) and/or reverse transcriptase (group II). However, only little is known about sponge intron mobility, transmission, and origin due to the lack of a comprehensive dataset. We analyzed the largest dataset on sponge mitochondrial group I introns to date: 95 specimens, from 11 different sponge genera which provided novel insights into the evolution of group I introns.

RESULTS

For the first time group I introns were detected in four genera of the sponge family Scleritodermidae (Scleritoderma, Microscleroderma, Aciculites, Setidium). We demonstrated that group I introns in sponges aggregate in the most conserved regions of cox1. We showed that co-occurrence of two introns in cox1 is unique among metazoans, but not uncommon in sponges. However, this combination always associates an active intron with a degenerating one. Earlier hypotheses of HGT were confirmed and for the first time VGT and secondary losses of introns conclusively demonstrated.

CONCLUSION

This study validates the subclass Spirophorina (Tetractinellida) as an intron hotspot in sponges. Our analyses confirm that most sponge group I introns probably originated from fungi. DNA barcoding is discussed and the application of alternative primers suggested.

Development of a multilocus-based approach for sponge (phylum Porifera) identification: refinement and limitations

For sponges (phylum Porifera), there is no reliable molecular protocol available for species identification. To address this gap, we developed a multilocus-based Sponge Identification Protocol (SIP) validated by a sample of 37 sponge species belonging to 10 orders from South Australia. The universal barcode COI mtDNA, 28S rRNA gene (D3-D5), and the nuclear ITS1-5.8S-ITS2 region were evaluated for their suitability and capacity for sponge identification. The highest Bit Score was applied to infer the identity. The reliability of SIP was validated by phylogenetic analysis. The 28S rRNA gene and COI mtDNA performed better than the ITS region in classifying sponges at various taxonomic levels. A major limitation is that the databases are not well populated and possess low diversity, making it difficult to conduct the molecular identification protocol. The identification is also impacted by the accuracy of the morphological classification of the sponges whose sequences have been submitted to the database. Re-examination of the morphological identification further demonstrated and improved the reliability of sponge identification by SIP. Integrated with morphological identification, the multilocus-based SIP offers an improved protocol for more reliable and effective sponge identification, by coupling the accuracy of different DNA markers.

Phylogenetic Reassessment of Antarctic Tetillidae (Demospongiae, Tetractinellida) Reveals New Genera and Genetic Similarity among Morphologically Distinct Species

Species of Tetillidae are distributed worldwide. However, some genera are unresolved and only a few genera and species of this family have been described from the Antarctic. The incorporation of 25 new COI and 18S sequences of Antarctic Tetillidae to those used recently for assessing the genera phylogeny, has allowed us to improve the resolution of some poorly resolved nodes and to confirm the monophyly of previously identified clades. Classical genera such as Craniella recovered their traditional diagnosis by moving the Antarctic Tetilla from Craniella, where they were placed in the previous family phylogeny, to Antarctotetilla gen. nov. The morphological re-examination of specimens used in the previous phylogeny and their comparison to the type material revealed misidentifications. The proposed monotypic new genus Levantinella had uncertain phylogenetic relationships depending on the gene partition used. Two more clades would require the inclusion of additional species to be formally established as new genera. The parsimony tree based on morphological characters and the secondary structure of the 18S (V4 region) almost completely matched the COI M1-M6 and the COI+18S concatenated phylogenies. Morphological synapomorphies have been identified for the genera proposed. New 15 28S (D3-D5) and 11 COI I3-M11 partitions were exclusively sequenced for the Antarctic species subset. Remarkably, species within the Antarctic genera Cinachyra (C. barbata and C. antarctica) and Antarctotetilla (A. leptoderma, A. grandis, and A. sagitta), which are clearly distinguishable morphologically, were not genetically differentiated with any of the markers assayed. Thus, as it has been reported for other Antarctic sponges, both the mitochondrial and nuclear partitions used did not differentiate species that were well characterized morphologically. Antarctic Tetillidae offers a rare example of genetically cryptic (with the traditional markers used for sponges), morphologically distinct species.

Molecular biodiversity of Red Sea demosponges

Sponges are important constituents of coral reef ecosystems, including those around the Arabian Peninsula. Despite their importance, our knowledge on demosponge diversity in this area is insufficient to recognize, for example, faunal changes caused by anthropogenic disturbances. We here report the first assessment of demosponge molecular biodiversity from Arabia, with focus on the Saudi Arabian Red Sea, based on mitochondrial and nuclear ribosomal molecular markers gathered in the framework of the Sponge Barcoding Project. We use a rapid molecular screening approach on Arabian demosponge collections and analyze results in comparison against published material in terms of biodiversity. We use a variable region of 28S rDNA, applied for the first time in the assessment of demosponge molecular diversity. Our data constitutes a solid foundation for a future more comprehensive understanding of sponge biodiversity of the Red Sea and adjacent waters.

Diversity in a Cold Hot-Spot: DNA-Barcoding Reveals Patterns of Evolution among Antarctic Demosponges (Class Demospongiae, Phylum Porifera)

Background

The approximately 350 demosponge species that have been described from Antarctica represent a faunistic component distinct from that of neighboring regions. Sponges provide structure to the Antarctic benthos and refuge to other invertebrates, and can be dominant in some communities. Despite the importance of sponges in the Antarctic subtidal environment, sponge DNA barcodes are scarce but can provide insight into the evolutionary relationships of this unique biogeographic province.

Methodology/Principal Findings

We sequenced the standard barcoding COI region for a comprehensive selection of sponges collected during expeditions to the Ross Sea region in 2004 and 2008, and produced DNA-barcodes for 53 demosponge species covering about 60% of the species collected. The Antarctic sponge communities are phylogenetically diverse, matching the diversity of well-sampled sponge communities in the Lusitanic and Mediterranean marine provinces in the Temperate Northern Atlantic for which molecular data are readily available. Additionally, DNA-barcoding revealed levels of in situ molecular evolution comparable to those present among Caribbean sponges. DNA-barcoding using the Segregating Sites Algorithm correctly assigned approximately 54% of the barcoded species to the morphologically determined species.

Conclusion/Significance

A barcode library for Antarctic sponges was assembled and used to advance the systematic and evolutionary research of Antarctic sponges. We provide insights on the evolutionary forces shaping Antarctica's diverse sponge communities, and a barcode library against which future sequence data from other regions or depth strata of Antarctica can be compared. The opportunity for rapid taxonomic identification of sponge collections for ecological research is now at the horizon.

Deceptive desmas: molecular phylogenetics suggests a new classification and uncovers convergent evolution of lithistid demosponges

Reconciling the fossil record with molecular phylogenies to enhance the understanding of animal evolution is a challenging task, especially for taxa with a mostly poor fossil record, such as sponges (Porifera). 'Lithistida', a polyphyletic group of recent and fossil sponges, are an exception as they provide the richest fossil record among demosponges. Lithistids, currently encompassing 13 families, 41 genera and >300 recent species, are defined by the common possession of peculiar siliceous spicules (desmas) that characteristically form rigid articulated skeletons. Their phylogenetic relationships are to a large extent unresolved and there has been no (taxonomically) comprehensive analysis to formally reallocate lithistid taxa to their closest relatives. This study, based on the most comprehensive molecular and morphological investigation of 'lithistid' demosponges to date, corroborates some previous weakly-supported hypotheses, and provides novel insights into the evolutionary relationships of the previous 'order Lithistida'. Based on molecular data (partial mtDNA CO1 and 28S rDNA sequences), we show that 8 out of 13 'Lithistida' families belong to the order Astrophorida, whereas Scleritodermidae and Siphonidiidae form a separate monophyletic clade within Tetractinellida. Most lithistid astrophorids are dispersed between different clades of the Astrophorida and we propose to formally reallocate them, respectively. Corallistidae, Theonellidae and Phymatellidae are monophyletic, whereas the families Pleromidae and Scleritodermidae are polyphyletic. Family Desmanthidae is polyphyletic and groups within Halichondriidae--we formally propose a reallocation. The sister group relationship of the family Vetulinidae to Spongillida is confirmed and we propose here for the first time to include Vetulina into a new Order Sphaerocladina. Megascleres and microscleres possibly evolved and/or were lost several times independently in different 'lithistid' taxa, and microscleres might at least be four times more likely lost than megascleres. Desma spicules occasionally may have undergone secondary losses too. Our study provides a framework for further detailed investigations of this important demosponge group.

Composition and predicted functional ecology of mussel-associated bacteria in Indonesian marine lakes

In the present study, we sampled bacterial communities associated with mussels inhabiting two distinct coastal marine ecosystems in Kalimantan, Indonesia, namely, marine lakes and coastal mangroves. We used 16S rRNA gene pyrosequencing and predicted metagenomic analysis to compare microbial composition and function. Marine lakes are small landlocked bodies of seawater isolated to varying degrees from the open sea environment. They contain numerous endemic taxa and represent natural laboratories of speciation. Our primary goals were to (1) use BLAST search to identify closely related organisms to dominant bacterial OTUs in our mussel dataset and (2) to compare bacterial communities and enrichment in the predicted bacterial metagenome among lakes. Our sequencing effort yielded 3553 OTUs belonging to 44 phyla, 99 classes and 121 orders. Mussels in the largest marine lake (Kakaban) and the coastal mangrove habitat were dominated by bacteria belonging to the phylum Proteobacteria whereas smaller lakes, located on the island of Maratua, were dominated by bacteria belonging to the phyla Firmicutes and Tenericutes. The single most abundant OTU overall was assigned to the genus Mycoplasma. There were several significant differences among locations with respect to metabolic pathways. These included enrichment of xenobiotic biodegradation pathways in the largest marine lake and coastal mangrove. These locations were also the most enriched with respect to nitrogen metabolism. The presence of genes related to isoquinoline alkaloids, polyketides, hydrolases, mono and dioxygenases in the predicted analysis of functional pathways is an indication that the bacterial communities of Brachidontes mussels may be potentially important sources of new marine medicines and enzymes of industrial interest. Future work should focus on measuring how mussel microbial communities influence nutrient dynamics within the marine lake environment and isolating microbes with potential biotechnological applications.

Two distinct microbial communities revealed in the sponge Cinachyrella

Marine sponges are vital components of benthic and coral reef ecosystems, providing shelter and nutrition for many organisms. In addition, sponges act as an essential carbon and nutrient link between the pelagic and benthic environment by filtering large quantities of seawater. Many sponge species harbor a diverse microbial community (including Archaea, Bacteria and Eukaryotes), which can constitute up to 50% of the sponge biomass. Sponges of the genus Cinachyrella are common in Caribbean and Floridian reefs and their archaeal and bacterial microbiomes were explored here using 16S rRNA gene tag pyrosequencing. Cinachyrella specimens and seawater samples were collected from the same South Florida reef at two different times of year. In total, 639 OTUs (12 archaeal and 627 bacterial) belonging to 2 archaeal and 21 bacterial phyla were detected in the sponges. Based on their microbiomes, the six sponge samples formed two distinct groups, namely sponge group 1 (SG1) with lower diversity (Shannon-Weiner index: 3.73 ± 0.22) and SG2 with higher diversity (Shannon-Weiner index: 5.95 ± 0.25). Hosts' 28S rRNA gene sequences further confirmed that the sponge specimens were composed of two taxa closely related to Cinachyrella kuekenthalli. Both sponge groups were dominated by Proteobacteria, but Alphaproteobacteria were significantly more abundant in SG1. SG2 harbored many bacterial phyla (>1% of sequences) present in low abundance or below detection limits (<0.07%) in SG1 including: Acidobacteria, Chloroflexi, Gemmatimonadetes, Nitrospirae, PAUC34f, Poribacteria, and Verrucomicrobia. Furthermore, SG1 and SG2 only had 95 OTUs in common, representing 30.5 and 22.4% of SG1 and SG2's total OTUs, respectively. These results suggest that the sponge host may exert a pivotal influence on the nature and structure of the microbial community and may only be marginally affected by external environment parameters.