| Mycale hentscheli | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Porifera |
| Class: | Demospongiae |
| Order: | Poecilosclerida |
| Family: | Mycalidae |
| Genus: | Mycale |
| Species: | M. hentscheli |
| Binomial name | |
| Mycale hentscheli | |
Mycale hentscheli is a marine sponge, which is known to be a rich source of bioactive small molecules. These natural products originate from the sponge's microbiota. Examples of these molecules include the potent cytotoxic polyketides: pateamine, peloruside, and mycalamide. [1] [2]
Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynthesis, and application of polyketides has evolved. It is a large and diverse group of secondary metabolites caused by its complex biosynthesis which resembles that of fatty acid synthesis. Because of this diversity, polyketides can have various medicinal, agricultural, and industrial applications. Many polyketides are medicinal or exhibit acute toxicity. Biotechnology has enabled discovery of more naturally-occurring polyketides and evolution of new polyketides with novel or improved bioactivity.
Okadaic acid, C44H68O13, is a toxin produced by several species of dinoflagellates, and is known to accumulate in both marine sponges and shellfish. One of the primary causes of diarrhetic shellfish poisoning, okadaic acid is a potent inhibitor of specific protein phosphatases and is known to have a variety of negative effects on cells. A polyketide, polyether derivative of a C38 fatty acid, okadaic acid and other members of its family have shined light upon many biological processes both with respect to dinoflagellete polyketide synthesis as well as the role of protein phosphatases in cell growth.
Polyene antimycotics, sometimes referred to as polyene antibiotics, are a class of antimicrobial polyene compounds that target fungi. These polyene antimycotics are typically obtained from some species of Streptomyces bacteria. Previously, polyenes were thought to bind to ergosterol in the fungal cell membrane and thus weakening it and causing leakage of K+ and Na+ ions, which could contribute to fungal cell death. However, more detailed studies of polyene molecular properties have challenged this model suggesting that polyenes instead bind and extract ergosterol directly from the cellular membrane thus disrupting the many cellular functions ergosterols perform. Amphotericin B, nystatin, and natamycin are examples of polyene antimycotics. They are a subgroup of macrolides.
Maitotoxin is an extremely powerful biotoxin produced by Gambierdiscus toxicus, a dinoflagellate species. Maitotoxin has been shown to be more than one hundred thousand times more potent than VX nerve agent. Maitotoxin is so potent that it has been demonstrated that an intraperitoneal injection of 130 ng/kg was lethal in mice. Maitotoxin was named from the ciguateric fish Ctenochaetus striatus—called "maito" in Tahiti—from which maitotoxin was isolated for the first time. It was later shown that maitotoxin is actually produced by the dinoflagellate Gambierdiscus toxicus.
Polyketide synthases (PKSs) are a family of multi-domain enzymes or enzyme complexes that produce polyketides, a large class of secondary metabolites, in bacteria, fungi, plants, and a few animal lineages. The biosyntheses of polyketides share striking similarities with fatty acid biosynthesis.
Cryptophycins are a family of macrolide molecules that are potent cytotoxins and have been studied for potential antiproliferative properties useful in developing chemotherapy. They are members of the depsipeptide family.
In ecology, the term productivity refers to the rate of generation of biomass in an ecosystem, usually expressed in units of mass per volume per unit of time, such as grams per square metre per day. The unit of mass can relate to dry matter or to the mass of generated carbon. The productivity of autotrophs, such as plants, is called primary productivity, while the productivity of heterotrophs, such as animals, is called secondary productivity.
Spicules are structural elements found in most sponges. The meshing of many spicules serves as the sponge's skeleton and thus it provides structural support and potentially defense against predators.
Callystatin A is a polyketide natural product from the leptomycin family of secondary metabolites. It was first isolated in 1997 from the marine sponge Callyspongia truncata which was collected from the Goto Islands in the Nagasaki Prefecture of Japan by the Kobayashi group. Since then its absolute configuration has been elucidated and callystatin A was discovered to have anti-fungal and anti-tumor activities with extreme potency against the human epidermoid carcinoma KB cells (IG50 = 10 pg/ml) and the mouse lymphocytic leukemia Ll210 cells (IG50 = 20 pg/ml).
Callyspongia truncata is a species of marine sea sponge. Like all marine sponges, C. truncata is a member of phylum Porifera and is defined by its filter-feeding lifestyle and flagellated choanocytes, or collar cells, that allow for water movement and feeding. It is a species of demosponge and a member of Demospongiae, the largest class of sponges as well as the family Callyspongiidae. C. truncata is most well-known for being the organism from which the polyketide Callystatin A was identified. Callystatin A is a polyketide natural product from the leptomycin family of antibiotics. It was first isolated in 1997 from this organism, which was collected from the Goto Islands in the Nagasaki Prefecture of Japan by the Kobayashi group. Recent studies have revealed numerous other bioactive compounds that have been found in this species.
A microbiome is the community of microorganisms that can usually be found living together in any given habitat. It was defined more precisely in 1988 by Whipps et al. as "a characteristic microbial community occupying a reasonably well-defined habitat which has distinct physio-chemical properties. The term thus not only refers to the microorganisms involved but also encompasses their theatre of activity". In 2020, an international panel of experts published the outcome of their discussions on the definition of the microbiome. They proposed a definition of the microbiome based on a revival of the "compact, clear, and comprehensive description of the term" as originally provided by Whipps et al., but supplemented with two explanatory paragraphs. The first explanatory paragraph pronounces the dynamic character of the microbiome, and the second explanatory paragraph clearly separates the term microbiota from the term microbiome.
Poribacteria are a candidate phylum of bacteria originally discovered in the microbiome of marine sponges (Porifera). Poribacteria are Gram-negative primarily aerobic mixotrophs with the ability for oxidative phosphorylation, glycolysis, and autotrophic carbon fixation via the Wood – Ljungdahl pathway. Poribacterial heterotrophy is characterised by an enriched set of glycoside hydrolases, uronic acid degradation, as well as several specific sulfatases. This heterotrophic repertoire of poribacteria was suggested to be involved in the degradation of the extracellular sponge host matrix.
Atrop-abyssomicin C is a polycyclic polyketide-type natural product that is the atropisomer of abyssomicin C. It is a spirotetronate that belongs to the class of tetronate antibiotics, which includes compounds such as tetronomycin, agglomerin, and chlorothricin. In 2006, the Nicolaou group discovered atrop-abyssomicin C while working on the total synthesis of abyssomicin C. Then in 2007, Süssmuth and co-workers isolated atrop-abyssomicin C from Verrucosispora maris AB-18-032, a marine actinomycete found in sediment of the Japanese sea. They found that atrop-abyssomicin C was the major metabolite produced by this strain, while abyssomicin C was a minor product. The molecule displays antibacterial activity by inhibiting the enzyme PabB, thereby depleting the biosynthesis of p-aminobenzoate.
Onnamide A is a bioactive natural product found in Theonella swinhoei, a species of marine sponge whose genus is well known for yielding a diverse set of biologically active natural products, including the swinholides and polytheonamides. It bears structural similarities to the pederins, a family of compounds known to inhibit protein synthesis in eukaryotic cells. Onnamide A and its analogues have attracted academic interest due to their cytotoxicity and potential for combating the growth and proliferation of cancer cells.
Dysidea arenaria is a species of marine sponge (poriferan) found in the Pacific Ocean. It is a member of the order Dictyoceratida, one of two sponge orders that make up the keratose or "horny" sponges in which a mineral skeleton is absent and a skeleton of organic fibers is present instead.
Geodia barretti is a massive deep-sea sponge species found in the boreal waters of the North Atlantic Ocean, and is fairly common on the coasts of Norway and Sweden. It is a dominant species in boreal sponge grounds. Supported by morphology and molecular data, this species is classified in the family Geodiidae.
Hologenomics is the omics study of hologenomes. A hologenome is the whole set of genomes of a holobiont, an organism together with all co-habitating microbes, other life forms, and viruses. While the term hologenome originated from the hologenome theory of evolution, which postulates that natural selection occurs on the holobiont level, hologenomics uses an integrative framework to investigate interactions between the host and its associated species. Examples include gut microbe or viral genomes linked to human or animal genomes for host-microbe interaction research. Hologenomics approaches have also been used to explain genetic diversity in the microbial communities of marine sponges.
24-isopropyl cholestane is an organic molecule produced by specific sponges, protists and marine algae. The identification of this molecule at high abundances in Neoproterozoic rocks has been interpreted to reflect the presence of multicellular life prior to the rapid diversification and radiation of life during the Cambrian explosion. In this transitional period at the start of the Phanerozoic, single-celled organisms evolved to produce many of the evolutionary lineages present on Earth today. Interpreting 24-isopropyl cholestane in ancient rocks as indicating the presence of sponges before this rapid diversification event alters the traditional understanding of the evolution of multicellular life and the coupling of biology to changes in end-Neoproterozoic climate. However, there are several arguments against causally linking 24-isopropyl cholestane to sponges based on considerations of marine algae and the potential alteration of organic molecules over geologic time. In particular the discovery of 24-isopropyl cholestane in rhizarian protists implies that this biomarker cannot be used on its own to trace sponges. Interpreting the presence of 24-isopropyl cholestane in the context of changingglobal biogeochemical cycles at the Proterozoic-Phanerozoic transition remains an area of active research.
Swinholides are dimeric 42 carbon-ring polyketides that exhibit a 2-fold axis of symmetry. Found mostly in the marine sponge Theonella, swinholides encompass cytotoxic and antifungal activities via disruption of the actin skeleton. Swinholides were first described in 1985 and the structure and stereochemistry were updated in 1989 and 1990, respectively. Thirteen swinholides have been described in the literature, including close structural compounds such as misakinolides/bistheonellides, ankaraholides, and hurgholide A It is suspected that symbiotic microbes that inhabit the sponges rather than the sponges themselves produce swinholides since the highest concentration of swinholides are found in the unicellular bacterial fraction of sponges and not in the sponge fraction or cyanobacteria fraction that also inhabit the sponges.
Gert Wörheide is a German marine biologist who works mainly on marine invertebrates. He earned his doctorate in geobiology from Georg-August-Universität, following this with a post-doctorate at Queensland Museum (1998-2002), where he worked with John Hooper on sponges, a collaboration which continues.