Besides the most prominent peptide toxin microcystin the cyanobacteria spp. in
April 1, 2017
Besides the most prominent peptide toxin microcystin the cyanobacteria spp. in Kütz.; instead colonies of this species contained anabaenopeptins and/or microginins or unknown peptides. Within a third group (Kom.) Kom. in Kondr. chiefly a cyanopeptolin and an unknown peptide were found. Similar patterns however were also found in colonies which could not be identified to species level. The significance of oligopeptides as a chemotaxonomic tool within the genus is discussed. It could be demonstrated that the typing of single colonies by MALDI-TOF MS may be a valuable tool for ecological studies of the genus as well as in early warning of toxic cyanobacterial blooms. Freshwater and marine cyanobacteria are known to produce a variety of bioactive compounds among them potent hepatotoxins and neurotoxins (for an overview see reference 45). Many of the toxic species of cyanobacteria tend to massive proliferation in eutrophicated water bodies and thus have been the cause for considerable hazards for animal and human health (3 23 One of the most Doramapimod widespread bloom-forming cyanobacteria is the genus as a coccal unicellular cyanobacterium that grows as mucilaginous colonies of irregularly arranged cells (under natural conditions while strain cultures usually grow as single cells). According to this tradition morphological criteria such as size of the individual cells colony morphology and mucilage characteristics are used for species delimitation within (i.e. morphospecies) (20 21 Microcystin-producing strains as Doramapimod well as strains that do not synthesize microcystin have been reported for all species within the genus and studied to date were found to contain microcystins (17 47 49 strains of have only sporadically been reported to contain microcystins (34 38 49 Beside microcystins various other linear and cyclic oligopeptides such as aeruginosins anabaenopeptilides cyanopeptolins anabaenopeptins and microginins are found within the genus (31). Similar to microcystins these peptides possess unusual amino acids like 3-amino-6-hydroxy-2-piperidone (Ahp) in cyanopeptolins or 2-carboxy-6-hydroxyoctahydroindol (Choi) in aeruginosin-type molecules and numerous structural variants also exist within these groups (14 29 31 These peptides show diverse bioactivities frequently protease inhibition (31). The presence of d-amino Doramapimod acids unusual amino acids as well as their small size suggests that the cyanobacterial oligopeptides mentioned above are synthesized nonribosomally by multifunctional enzyme complexes generally termed peptide synthetases a pathway studied intensively in other bacteria and fungi (1 19 The nonribosomal synthesis of microcystins in the axenic strain sp. strain PCC 7806 and of anabaenopeptilides in sp. strain 90 was recently demonstrated by site-directed mutagenesis and sequencing (6 42 46 Nonribosomal peptide synthetase genes have so far been detected in all strains of the genus spp. (7 35 This corresponds to the observation of oligopeptides in all strains investigated to date showing various combinations of microcystins and/or other Doramapimod oligopeptides such as aeruginosins cyanopeptolins or anabaenopeptins (8 27 31 The cooccurrence of both microcystins and other oligopeptides such as anabaenopeptins and cyanopeptolins in natural populations Rabbit Polyclonal to PPP2R3C. was recently demonstrated (10 14 36 It is well known that the species and genotype composition in natural populations is heterogeneous and both microcystin- and non-microcystin-containing strains have been isolated from the same sample (41 48 52 Rohrlack et al. (41) isolated 13 strains from Lake Wannsee (Berlin Germany) in 1995 which produced either microcystins or anabaenopeptins (T. Rohrlack M. Erhard and M. Henning unpublished data). Furthermore isolated strains may show both a different qualitative and quantitative microcystin pattern than the original population (41 48 These results suggest a considerable diversity of genotypes with different Doramapimod oligopeptide patterns in natural populations. Our study aimed to investigate the inter- and intraspecific oligopeptide diversity in a natural population of the genus colonies selected from natural populations using matrix-assisted laser desorption ionization-time of flight mass.