Suberites

''Suberites'' is a genus of sea sponges in the family Suberitidae.
Sponges, known scientifically as ''Porifera'', are the oldest metazoans and are used to elucidate the basics of multicellular evolution. These living fossils are ideal for studying the principal features of metazoans, such as extracellular matrix interactions, signal-receptor systems, nervous or sensory systems, and primitive immune systems. Thus, sponges are useful tools with which to study early animal evolution. They appeared approximately 580 million years ago, in the Ediacaran.

Evolutionary significance

As members of the oldest phylum of metazoans, ''Suberites'' serve as model organisms to elucidate features of the earliest animals.
''Suberites'' and their relatives are used to determine the structure of the first metazoans
and have been studied to determine how totipotency has replaced by pluripotency in most higher animals. Among other things, ''Suberites'' show that tyrosine-phosphorylation machinery evolved in animals independently from other eukaryotes. ''Suberites'' are also used as models to elucidate the evolution of transmembrane receptors and cell-junction proteins.
A combination of stem cell and apoptosis factors studies is used as a model for studies of development in higher animals.

Ecology

''Suberites'' are a global genus. One species, ''Suberites zeteki'', is found in Hawaii. ''S. zeteki'' associates with many fungi.G. Zheng, L. Binglin, Z. Chengchao, W. Guangyi, Molecular Detection of Fungal Communities in the Hawaiian Marine Sponges Suberites zeteki and Mycale armata. Applied & Environmental Microbiology 74, 6091 (2008). Another, ''S. japonicas'', is native to the waters around Japan.C. Tanaka, J. Tanaka, R. F. Bolland, G. Marriott, T. Higa, Seragamides A–F, new actin-targeting depsipeptides from the sponge Suberites japonicus Thiele. Tetrahedron 62, 3536 (2006). ''S. aurantiacus'' is found in the Caribbean sea.L. P. Ponomarenko, O. A. Vanteeva, S. A. Rod'kina, V. B. Krasokhin, S. S. Afiyatullov, Metabolites of the marine sponge Suberites cf. aurantiacus. Chemistry of Natural Compounds 46, 335 (2010). ''S.carnosus'' lives in the Indian Ocean and in the Mediterranean Sea and can also be found in Irish waters.B. Flemer et al., Diversity and antimicrobial activities of microbes from two Irish marine sponges, Suberites carnosus and Leucosolenia sp. Journal of Applied Microbiology 112, 289 (2012). ''S. diversicolor'' can be found in Indonesia. Due to ''Suberites’'' ability to efficiently filter water, many microbes, especially fungal species, are filtered through. If these microbes escape digestion, they can deposit on the sponge and reside there indefinitely. Symbiotic bacteria produce toxins, such as okadaic acid, which defend them from colonization by parasitic annelids.H. C. Schröder et al., Okadaic Acid, an Apoptogenic Toxin for Symbiotic/Parasitic Annelids in the Demosponge Suberites domuncula. Applied & Environmental Microbiology 72, 4907 (2006).W. E. G. Müller et al., Oxygen-Controlled Bacterial Growth in the Sponge Suberites domuncula: toward a Molecular Understanding of the Symbiotic Relationships between Sponge and Bacteria. Applied & Environmental Microbiology 70, 2332 (2004). Expression of various enzymes by ''Suberites'' influences the growth of their symbiotic bacteria. ''Suberites'' often live on the shells on the mollusk ''Hexaplex trunculus''. ''Suberites'' have mechanisms of defense against predation, such as the toxic chemicals found below.

Physiology

''Suberites'' display neuronal communications, but neuronal networks are mysteriously missing. However, they do have many of the same sensory receptors and signals found in higher animals.X. Wang, X. Fan, H. Schröder, W. Müller, Flashing light in sponges through their siliceous fiber network: A new strategy of 'neuronal transmission' in animals. Chinese Science Bulletin 57, 3300 (2012). Researchers in China and Germany have found that sponge spicules contribute to their neural communication.W. E. G. Müller et al., Luciferase a light source for the silica-based optical waveguides (spicules) in the demosponge Suberites domuncula. Cellular and Molecular Life Sciences 66, 537 (2009). In effect, the silicaceous structures act as fiber optic cables to convey light signals generated from the protein luciferase. The sponges generate light from luciferin, after it is acted upon by luciferase.W. E. G. Müller et al., A cryptochrome-based photosensory system in the siliceous sponge Suberites domuncula (Demospongiae). FEBS Journal 277, 1182 (2010). ''Suberites'' have also been shown to produce light in response to tactile stimulation. ''Suberites'' consist mostly of cells, in contrast with other ''Porifera'' (such as the class Hexactinellida) which are syncytial. As a result, ''Suberites'' have slower reaction times in their neural communication. ''Suberites'' utilized many Ras-like GTPases which are used for signaling and affect development. According to comparative studies, ''Suberites'' have some of the most simple indicator proteins, such as collagen, of known animals. Like all sponges, ''Suberites'' are filter-feeders. They are extremely efficient and can process thousands of liters of water per day. ''S. domuncula'' has been used for study of graft rejection. Researchers have discovered that apoptotic factors are induced in the tissue that is rejected.

Development

''Suberites'' consist of many telomerase-positive cells, which means the cells are essentially immortal, barring cell death signal. In most cases, the signal is a lack of connection either to the extracellular matrix or other cells. Their apoptotic cells are similar to homologous to mammalian. However, maintenance of long-lived cells involves proteins such as SDLAGL that are highly similar to yeast and human homologs. Certain inorganic materials, such as iron and selenium, influence the growth of ''Suberites'', including the primmorph growth and spicule formation. ''Suberites'' undergo cell differentiation through a variety of mechanisms based on cell-cell communication.

Morphology

''Suberites'' are key examples of the importance of the extracellular matrix in animals. In sponges, it is mediated by proteoglycans. Spicule formation is also important for ''Suberites''. Spicules are structural support of sponges, similar to skeletons in higher animals. They are normally hollow structures that are formed by lamellar growth.H. C. Schröder et al., Biosilica formation in spicules of the sponge Suberites domuncula: Synchronous expression of a gene cluster. Genomics 85, 666 (2005).H. C. Schröder et al., Apposition of silica lamellae during growth of spicules in the demosponge Suberites domuncula: Biological/biochemical studies and chemical/biomimetical confirmation. Journal of Structural Biology 159, 325 (2007). Whereas higher animal skeletons are largely calcium-based, sponge spicules consist mostly of silica, a silicon dioxide polymer.W. Xiaohong et al., Evagination of Cells Controls Bio-Silica Formation and Maturation during Spicule Formation in Sponges. PLoS ONE 6, 1 (2011). These inorganic structures provide support for the animals.X. Wang et al., Silicateins, silicatein interactors and cellular interplay in sponge skeletogenesis: formation of glass fiber-like spicules. FEBS Journal 279, 1721 (2012). The spicules are biologically-formed silica structures, also known as biosilica. Silica deposition begins intracellularly and is carried out by the enzyme silicatein. Silicateins are modulated by a group of proteins called silintaphins. The process occurs in specialized cells known as sclerocytes. Biosilica formation in ''Suberites'' differs from other species that utilize biosilica in this regard. Most other species, such as certain plants and diatoms, simply deposit a supersaturated biosilica solution. The network of silica found in sponges mediates much of the sponges’ neural communications.

Immunity and defense

''Suberites'' show the cytokine-like molecule allograft inflammatory factor one (AIF-1), which is similar to vertebrate AIF-1.H. C. Schröder et al., Functional Molecular Biodiversity: Assessing the Immune Status of Two Sponge Populations ( Suberites domuncula) on the Molecular Level. Marine Ecology 25, 93 (2004). Immune response relies on phosphorylation cascades involving the p38 kinase. ''S. domuncula'' was the first demonstrated immune response of invertebrate species (1). These sponges also have similar graft-response inflammation to vertebrates. Their immune systems are much simpler than vertebrates; they consist of only innate immunity. Because they filter thousands of liters of water per day, and their environment contains a high concentration of bacteria and viruses, ''Suberites'' have developed a highly potent system of immunity. Despite the efficiency of their immune systems, ''Suberites'' can be susceptible to infection which often stimulates cell death through apoptotic pathways.

''Suberites'', namely ''S. domuncula'', defend themselves from macroscopic threats with a neurotoxin known as suberitine.L. Cariello, L. Zanetti, Suberitine, the toxic protein from the marine sponge suberites domuncula. Comparative Biochemistry and Physiology 64C, 15 (1979). It was the first known protein discovered in a sponge. The neurotoxic properties of suberitine arise from its ability to block action potentials.L. Cariello, E. Tosti, L. Zanetti, The hemolytic activity of suberitine. Comparative Biochemistry and Physiology 73C, 91 (1981). It additionally has hemolytic properties, which do not originate from phospholipase A activity. It has some antibacterial activity; however, the extent of the activity due solely to suberitine is not currently defined. The sponge itself neutralizes the toxin through a pathway that is not fully understood, but involves retinal, a β-carotene metabolite. ''S. japonicas'' also produces several cytotoxic compounds, seragamides A-F. The seragamides act by interfering with cytoskeleton activity, specifically the actin microfilaments. The activity of the seragamides is a possible route for anti-cancer drugs, similar to existing drugs which target microtubules. ''Suberites'' also produce cytotoxic compounds known as nakijinamines, which resemble other toxins found in ''Suberites'', but the role of the nakijinamines has not yet been found.Y. Takahashi et al., Heteroaromatic alkaloids, nakijinamines, from a sponge Suberites sp. Tetrahedron 68, 8545 (2012). Many of the bioactive compounds found on ''Suberites'' are microbial in nature.

Species

The following species are recognised in the genus ''Suberites'':

* '' Suberites affinis'' Brøndsted, 1923
* ''Suberites anastomosus'' Brøndsted, 1924
* ''Suberites aurantiacus'' (Duchassaing & Michelotti, 1864)
* ''Suberites australiensis'' Bergquist, 1968
* ''Suberites axiatus'' Ridley & Dendy, 1886
* ''Suberites axinelloides'' Brøndsted, 1924
* ''Suberites baffini'' Brøndsted, 1933
* '' Suberites bengalensis'' Lévi, 1964
* ''Suberites caminatus'' Ridley & Dendy, 1886
* ''Suberites carnosus'' (Johnston, 1842)
* ''Suberites cebriones'' Morozov, Sabirov & Zimina, 2019
* ''Suberites clavatus'' Keller, 1891
* ''Suberites concinnus'' Lambe, 1895
* ''Suberites cranium'' Hajdu et al, 2013
* ''Suberites crelloides'' Marenzeller, 1886
* ''Suberites crispolobatus'' Lambe, 1895
* '' Suberites cupuloides'' Bergquist, 1961
* ''Suberites dandelenae'' Samaai & Maduray, 2017
* ''Suberites difficilis'' Dendy, 1897
* ''Suberites distortus'' Schmidt, 1870
* ''Suberites diversicolor'' Becking & Lim 2009
* ''Suberites domuncula'' (Olivi, 1792)
* ''Suberites excellens'' (Thiele, 1898)
* ''Suberites ficus'' (Johnston, 1842)
* ''Suberites flabellatus'' Carter, 1886
* ''Suberites gibbosiceps'' Topsent, 1904
* ''Suberites glaber'' Hansen, 1885
* ''Suberites glasenapii'' Merejkowski, 1879
* ''Suberites globosus'' Carter, 1886
* '' Suberites heros'' Schmidt, 1870
* ''Suberites hirsutus'' Topsent, 1927
* ''Suberites holgeri'' Van Soest & Hooper, 2020
* '' Suberites hystrix'' Schmidt, 1868
* ''Suberites insignis'' Carter, 1886
* '' Suberites japonicus'' Thiele, 1898
* ''Suberites kelleri'' Burton, 1930
* ''Suberites lambei'' Austin et al., 2014
* '' Suberites laticeps'' Topsent, 1904
* ''Suberites latus'' Lambe, 1893
* '' Suberites lobatus'' (Wilson, 1902)
* '' Suberites luna'' Giraldes & Goodwin, 2020
* ''Suberites luridus'' Solé-Cava & Thorpe, 1986
* ''Suberites lutea'' Sole-Cava & Thorpe, 1986
* '' Suberites mammilaris'' Sim & Kim, 1994
* ''Suberites massa'' Nardo, 1847
* ''Suberites microstomus'' Ridley & Dendy, 1887
* ''Suberites mineri'' (de Laubenfels, 1935)
* ''Suberites mollis'' Ridley & Dendy, 1886
* '' Suberites montalbidus'' Carter, 1880
* ''Suberites pagurorum'' Solé-Cava & Thorpe, 1986
* ''Suberites paradoxus'' Wilson, 1931
* ''Suberites perfectus'' Ridley & Dendy, 1886
* '' Suberites pisiformis'' Lévi, 1993
* ''Suberites placenta'' Thiele, 1898
* ''Suberites prototypus'' Czerniavsky, 1880
* ''Suberites puncturatus'' Thiele, 1905
* ''Suberites purpura'' Fortunato, Pérez & Lôbo-Hajdu, 2020
* ''Suberites radiatus'' Kieschnick, 1896
* '' Suberites ramosus'' Brøndsted, 1924
* '' Suberites rhaphidiophorus'' (Brøndsted, 1924)
* ''Suberites ruber'' Thiele, 1905
* ''Suberites rubrus'' Sole-Cava & Thorpe, 1986
* '' Suberites senilis'' Ridley & Dendy, 1886
* ''Suberites sericeus'' Thiele, 1898
* '' Suberites spermatozoon'' (Schmidt, 1875)
* ''Suberites spirastrelloides'' Dendy, 1897
* '' Suberites spongiosus'' Schmidt, 1868
* ''Suberites stilensis'' Burton, 1933
* '' Suberites strongylatus'' Sarà, 1978
* ''Suberites suberia'' (Montagu, 1818)
* ''Suberites syringella'' (Schmidt, 1868)
* '' Suberites topsenti'' (Burton, 1929)
* '' Suberites tortuosus'' Lévi, 1959
* ''Suberites tylobtusus'' Lévi, 1958
* ''Suberites verrilli'' Van Soest & Hooper, 2020
* '' Suberites virgultosus'' (Johnston, 1842)

References

{{Taxonbar, from=Q3463146

Suberitidae