Marine Sponge: Sponge-Bacteria Association

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Marine Sponges

Overview of Marine Sponges

Marine sponges are natural bath sponges (with living cells removed) that we all are familiar with. They actually are the oldest and simplest animals that have been living on earth for billions of years. There are various types of sponges under Phylum PORIFERA. They grow in every ocean in the world regardless of extreme temperatures. They can be found hundreds of meters under sea level but mostly are found in 5-50 meters deep. Marine sponges are filter-feeding animals because all adult sponges are sessile and can’t move around benthic surface. For approximately 20 centimeters sponge can filter up to 2000 liters of seawater during one day. Marine sponges have no true tissues or organs, just constructed with layers of cells even without nervous system. Inside the sponge, the vibration of ciliates, the special cells circulate seawater through small pores and absorb planktons and small sea organisms. (1)

Marine sponges come in different but striking colors, bright red, purple, yellow, and brown, etc. These colors and some are toxic as well may help them defend from sponge eating invertebrates and some fishes. Some other small marine organisms, fishes, and microscopic organisms often call marine sponges their homes. Sponges often have skeleton of spicules, which protect and give refuge to small invertebrates from other marine scavengers. (2)

Living Conditions/Locations

Sponges

Adjacent Communities

Microbes

Diversity

Sponge-Microbe Association

Microbial Metabolism of Sponges

Mutualism/Commensalism

Pathogens/Parasites

Interactions with Other Organisms

Type of Sponges

Genus: Aplysina

Species Aplysina archeri from Karsten Zengler
  1. Location: Caribbean and Mediterranean; shallow rocky substrates exposed to light (1-20m depth)
  2. Characteristics/Physical conditions:
- usually sulfur-yellow in color but can be tinged toward green or red
- sponge fibers made up of laminated,golden-bark and a granular, dark pith
- can protect large number of bacteria that can take up to 40% of its mass
- alternate between high water-pumping speed and low water circulation phase
- produce brominated aromatic mebolites such as bormoindoles, bromophenol(BP), polybrominated diphenyl ethers, and dibromodibenzo p-dioxins (can serve as a chemical defense against predators and biofouling)

Current Research

1. ITS-2 and 18S rRNA Gene Phylogeny of Aplysinidae (Verongida,Demospngiae), 2004

In order to identify the genus-level for sponges(Porifera) taxonomy, the researchers have been using their characteristics such as spicules and sponging fibers. However, it became noticeable that having a precise taxonomical classification of the Porifera was difficult especially if sponges were being identify only by using their morphological features. Therefore, this research was conducted to investigate if there is any other way to have a get a clear genus-level of different sponges. It revealed that matching up 18S ribosomal DNA and internal transcribed spacer 2 (ITS-2) full length sequences to certain marine sponge sequence can be used to build phylogenetic trees to arrange based on secondary structure. For this experiment, different sponges were analyzed such as eleven Aplysina sponges and three additional sponges (Cerongula gigantean, Aiolochroia crassa, Smenospongia aurea) from different location such as tropical and sub-tropical oceans. The results concluded that Aplysinais from a single common ancestor and stands at a basal position in both 18S and ITS-2 trees. The problem with this method is that the molecular data come out differently from the current taxonomy that was structured based on morphological characteristics. Therefore, the future research is to reevaluate the sponges as more 18S sequences become available. (6)

2. Biodegradation

Halogenated compounds are one of the biggest environmental pollutants on earth. In order to degrade these harmful bio-reactive materials, naturally occurring biodegradable compounds are needed. Marine sponges naturally produce brominated organic compounds for chemical defense against predators and biofouling. A bright yellow sponge family, Aplysina aerophoba constitutes 7-12% of bromine-containing metabolites in its dry weight. (3) They are abundantly found in subtropical and tropical waters of the Mediterranean Sea and Pacific and Atlantic oceans. The major secondary metabolites of this sponge are bromophenolic metabolites derived from dibromotyrosine. Interestingly, A. aerophoba is also a host to diverse microorganisms, which constitute 40% of its biomass. While the brominated compounds released by A. aerophoba are harmful to others but not to these microbial community is an inspired research for scientists.

The scientists are working on sponge-associated microorganisms that might have the ability to dehalogenate and degrade brominated compounds. They have isolated “a conserved reductive dehalogenase gene motif in the dehalorespiring bacteria D. ethenogenes, Dehalospirillum multivorans, and Desulfitobacterium dehalogenans.” (3) These dehalogenating bacteria debrominate the brominated compounds by anaerobic reductive activities. They are anaerobic because “most sponges alternate between periods of high water-pumping velocity and periods of low water circulation. It is possible that oxygen becomes limited during periods of low water circulation because of active respiration by the large number of bacteria present in the mesohyl, sponge’s gut.” (3) The diversity of genes motifs isolated from these bacteria is valuable for environmental biodegrading. Therefore, marine sponges along with dehalogenating bacteria serve as cues for scientific community to explore more about marine sponge and its valuable natural biodegrading compounds.

References

(1) www.zitak.hr/sponge.htm

(2)

(3) http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=12839794

(4) Ahn, Young-Beom, Sung-Keun Rhee, Donna E. Fennell, Lee J. Kerkhof, Ute Hentschel, and Max M. Haggblom. "Reductive Dehalogenation of Brominated Phenolic Compounds by Microorganisms Associated with the Marine Sponge Aplysina aerophoba." Applied and Environmental Microbiology 69.7 (2003): 4159-4166

(5)Fieseler, Lars, Matthias Horn, Michael Wagner, and Ute Hentschel. "Discovery of the Novel Candidate Phylum "Poribacteria" in Marine Sponges." Applied and Environmental Micobiology 70.6 (2004): 3724-3732.

(6) Schmitt, Susanne, Ute Hentschel, Steven Zea, Thomas Dandekar, and Matthias Wolf. "ITS-2 and 18S rRNA Gene Phylogeny of Aplysinidae (Verongida, Demospongiae)." J Molecular Evolution 60 (2004):327-336.

(7) Taylor, Michael W., Russell T Hill, Jorn Piel, Robert W Thacker, and Ute Hentschel. "Soaking it up: the complex lives of marine sponges and their microbial associates." The ISME Jornal 1 (2007):187-190.