Metabolite cyanobacteria

With advances in methods of isolation and cultivation of microalgae and cyanobacteria, and the striking bioactivity of other microbial metabolites, research into the chemistry of culturable algae has escalated since the 1990s. Metabolites from these... 

Nagle DG, Paul VJ (1999) Production of secondary metabolites by filamentous tropical marine cyanobacteria ecological functions of the compounds. J Phycol 35 1412-1421 Nagle DG, Camacho FT, Paul VJ (1998) Dietary preferences of the opisthobranch mollusc Stylocheilus longicauda for secondary metabolites produced by the tropical cyanobacterium Lyngbya majuscula. Mar Biol 132 267-273... 

The nonprotein amino acid /3-A -methylamino-L-alanine (BMAA) is a neurotoxin found in various species of marine cyanobacteria. This nonprotein amino acid occurs both as a free amino acid and bound to proteins.Siderophores are secondary metabolites generally produced by bacteria under iron-deficient conditions. These molecules sequester and transport ferric ion via active transport in bacteria. Some known siderophores are nonribosomal peptides that contain nonprotein amino acids with terminal amines or hydroxylamine side chains, such as exochelin Many of the known nonprotein amino... 

For example, in channel catfish Ictalurus punctatus) aquaculture ponds in the southeastern USA, some species of cyanobacteria produce earthy and musty metabolites such as geosmin and 2-methylisoborneol (MIB) (Fig. 1). These compounds are rapidly absorbed across the gills of the catfish and accumulate in the flesh of the catfish, thereby rendering them unpalatable and unmarketable. 

Lakes, rivers, swamps, and marshes - common in temperate areas - contribute little to the diversity of natural products. Abundant dull-green grass and dull-colored fish and moUusks characterize lakes and rivers, in contrasts with the vivid colors of tropical fish and seaweeds. Haplosclerid sponges are occasionally abundant in freshwater, but their secondary metabolism is limited to demospongic acids (Dembisky 1994), in contrast with the variety of metabolites from marine sponges in the same order. Where not for cyanobacteria (which are as rich of unusual metabolites as the marine strains), tropical amphibians, and aquatic fimgi, freshwater ecosystems would have passed unnoticed in this book. 

The list of natural product similarities from land and the sea is immense, with metabolites of all chemical classes. On land these mostly derive from bacteria, cyanobacteria, plants, fiingi, insects, amphibians, and mammals in the sea, besides bacteria and cyanobacteria, the sponges, cnidarians, bryozoans, moUusks, ascidians, and sharks produce most. The ascidians are exclusively marine, and the sponges, cnidarians, and bryozoans are productive only in the sea. Dietary metabolites are also... 

In the mollusks, only marine species are known for unusual metabolites. However, while polypropionates of marine pulmonates have de novo origin (Table 9.1), the secondary metabolites isolated from opisthobranch mollusks derive mostly from dietary cyanobacteria, seaweeds, and invertebrates. 

The main framework is made up of five key modules for chemical library editing, enumeration, conversion, visualization, and analysis. The operations of these functionalities are accomplished by the various applications at the resource layer. For the purpose of illustration, the compound calothrixin B, a secondary metabolite isolated from the Calothrix cyanobacteria (11-13), is used as the scaffold molecule with the variable functional groups Rw] attached (Fig. 18.1). The calothrixins are redox-active natural products which display potent antimalarial and anticancer properties and thus there is interest in probing the physical as well as biological profiles of their derivatives (14). In this exercise, six functional groups have been selected as the building blocks (Table 18.1). 

Rickards, R. W., Rothschild, J. M., Willis, A. C., de Chazal, N. M., Kirk, J., Kirk, K., Sal-iba, K. J., Smith, G. D. (1999) Calothrixins A and B, novel pentacyclic metabolites from Calothrix Cyanobacteria with potent activity against malaria parasites and human cancer cells. Tetrahedron Lett 55, 13513-13520. 

Cyanobacteria Ether, chlorinated metabolites, pigments Hentschel et al. (2006)... 

Cyanobacteria are photosynthetic prokaryotes that are widely distributed throughout marine and terrestrial environments. Members of the marine cyanobacteria genus Lyngbya are known to produce structurally interesting and biologically active secondary metabolites. Typically, linear/cyclic peptides and depsipeptides that include various nonproteinogenic amino acids are the major groups of these metabolites (Fig. 10.11), which can exhibit potent cytotoxicity. 

Although terrestrial cyanobacteria are well-recognized producers of a wide range of bioactive compounds, marine species have received less attention until recently [159]. One of the most abundant and studied marine cyanobacteria is the pantropic Lyngbya majuscula (Oscillatoriaceae). A prolific producer of metabolites, it has so far yielded more than 110 secondary metabolites including compounds that exhibit antiproliferative, immunosuppressants, antifeedant and molluscidal activities [159,160]. Shallow water varieties of the cyanophyte contain N-substituted amides of 75-methoxytetradec-4E-enoic acid and of 7S-methoxy-9-methylhexa-dec-4 -enoic acid called malyngamides, a sub-class of which contains the 4-methoxy-3-pyrrolin-2-one system [158]. 

Marine sponges of the genus Haliclona contain a diverse array of active secondary metabolites, including highly potent cytotoxic macrolides, e g., halichondrin and related compounds, Fig. (56) [468], and salicylihalamides A and B, Fig. (57) [469], New macrolides chemically related to salicylihalamides, apicularens A and B, were recently isolated from the myxobacteria Chondromyces sp. [470], From marine bacteria, other cytotoxic macrolides have been isolated, such as octalactin A, Fig. (58) and B, which have been shown as a cell cycle-specific anticancer drug [471], and swinholide, Fig. (59), isolated from symbiotic cyanobacteria with the marine sponge Theonella swinhoei [472]. 

The thiazoline and thiazole rings are present in many cyclic peptides isolated from marine organisms. Most of these types of compound have been isolated from tunicates belonging to the Lissoclinum and Didemnum genus, from sponges of the genus Theonella, and from the sea hare mollusc Dolabella auricularia. The isolation of closely related compounds from cyanobacteria pointed out the symbiont origin of these metabolites. 

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