Recipe for standard BG-11 media v1

Stanier RY, Deruelles J, Rippka R, Herdman M, Waterbury JB: Generic Assignments, Strain Histories and Properties of Pure Cultures of Cyanobacteria. Microbiology 1979, 111:1–61. Recipes for standard and alternative BG11 for culturing freshwater cyanobacteria, such as Synechocystis sp. PCC 6803, as described. Media is usually not suitable for marine cyanobacteria. Final Concentration of Medium. CaCl2*2 H2O 0.036 g/L Citric acid 0.006 g/L NaNO3 1.4958 g/L MgSO4* 7 H2O 0.0749 g/L 0.25M Na2EDTA (pH 8) 0.0056 mL/L Na2CO3 20 µg/ml Fe(III) Ammonium citrate 6 µg/ml K2HPO4 * 3H2O 30 µg/ml TES Buffer (pH 8) 10 mM H3BO3 2.86 mg/L MnCl2 * 4 H2O 1.81 mg/L ZnSO4 * 7 H2O 0.222 mg/L Na2MoO4 * 2 H2O 0.390 mg/L Co(NO3)2 *6 H2O 0.049 mg/L (CuSO4 * 5 H2O 0.079 mg/L if required)

Complex photobiont diversity in the marine lichen Lichina pygmaea

Lichens are a well-known symbiosis between a host mycobiont and eukaryote algal or cyanobacterial photobiont partner(s). Recent studies have indicated that terrestrial lichens can also contain other cryptic photobionts that increase the lichens’ ecological fitness in response to varying environmental conditions. Marine lichens live in distinct ecosystems compared with their terrestrial counterparts because of regular submersion in seawater and are much less studied. We performed bacteria 16S and eukaryote 18S rRNA gene metabarcoding surveys to assess total photobiont diversity within the marine lichen Lichina pygmaea (Lightf.) C. Agardh, which is widespread throughout the intertidal zone of Atlantic coastlines. We found that in addition to the established cyanobacterial photobiont Rivularia, L. pygmaea is also apparently host to a range of other marine and freshwater cyanobacteria, as well as marine eukaryote algae in the family Ulvophyceae (Chlorophyta). We propose that symbiosis with multiple freshwater and marine cyanobacteria and eukaryote photobionts may contribute to the ability of L. pygmaea to survive the harsh fluctuating environmental conditions of the intertidal zone.

Genetic engineering of marine cyanophages reveals integration but not lysogeny in T7-like cyanophages

Marine cyanobacteria of the genera Synechococcus and Prochlorococcus are the most abundant photosynthetic organisms on earth, spanning vast regions of the oceans and contributing significantly to global primary production. Their viruses (cyanophages) greatly influence cyanobacterial ecology and evolution. Although many cyanophage genomes have been sequenced, insight into the functional role of cyanophage genes is limited by the lack of a cyanophage genetic engineering system. Here, we describe a simple, generalizable method for genetic engineering of cyanophages from multiple families, that we named REEP for REcombination, Enrichment and PCR screening. This method enables direct investigation of key cyanophage genes, and its simplicity makes it adaptable to other ecologically relevant host-virus systems. T7-like cyanophages often carry integrase genes and attachment sites, yet exhibit lytic infection dynamics. Here, using REEP, we investigated their ability to integrate and maintain a lysogenic life cycle. We found that these cyanophages integrate into the host genome and that the integrase and attachment site are required for integration. However, stable lysogens did not form. The frequency of integration was found to be low in both lab cultures and the oceans. These findings suggest that T7-like cyanophage integration is transient and is not part of a classical lysogenic cycle.

Natural Bioactive Cyclopeptides from Microbes as Promising Anticancer Drug Leads: A Mini-review

Natural products from microbes are a rich source of bioactive molecules to serve as drug leads, predominantly in cancer therapy. Peptides are among the essential nature-derived biomolecules. Owing to their great diversity and favorable characteristics, cyclic peptides (cyclopeptides) from natural sources have become a propitious lead candidate for the development of therapeutics, including anticancer drugs. This present mini-review highlights cyclopeptides from microbial-derived natural products that have demonstrated significant cytotoxicity or anticancer activities. Moreover, this mini-review also provides a look into the mode of action of anticancer cyclopeptides. Selected examples are given for the potent anticancer cyclopeptides isolated in the recent decade from fungi and bacteria from both terrestrial and marine origins. Naturally occurring cyclopeptides with canonical and non-canonical amino acids isolated from fungi, myxobacteria, actinomycetes, marine cyanobacteria, and microbes associated with marine organisms and their anticancer activity are featured herein.

Mineralization of Melanoidin by H₂O₂ Producing Enzymes from Marine Cyanobacteria Oscillatoria boryana BDU 92181

Intracellular enzymes of Oscillatoria boryana BDU 92181 exhibited mineralizing activity on melanoidin, a recalcitrant pigment present in the distillery wastewater. Melanoidin decolourization was postulated to be due to the production of hydrogen peroxide and molecular oxygen released by the cyanobacterium during photosynthesis. The present study was aimed to find out the efficacy of the marine cyanobacterium O. boryana BDU 92181 in producing H2O2 and enzymes involved in hydrogen peroxide production with a view to utilize its potential for decolorization of melanoidin pigment in the distillery effluent. The enzymes involved in the melanoidin degradation have not so far been attempted with cyanobacteria. The results obtained in the present work suggested the activity of the glucose oxidase and Manganese peroxidase enzymes in a marine cyanobacterium Oscillatoria boryana BDU 92181 and whose activity was found to be enhanced in the presence of melanoidin.

Bacterial biosilicification: A new insight into the global silicon cycle

Biosilicification is the process by which organisms incorporate soluble, monomeric silicic acid, Si(OH)4, in the form of polymerized insoluble silica, SiO2. Biosilicifying eukaryotes, including diatoms, siliceous sponges, and higher plants, have been the targets of intense research to study the molecular mechanisms underlying biosilicification. By contrast, prokaryotic biosilicification has been less well studied, partly because the biosilicifying capability of well-known bacteria was not recognized until recently. This review summarizes recent findings on bacterial extracellular and intracellular biosilicification, the latter of which has been demonstrated only recently in bacteria. The topics discussed herein include bacterial (and archaeal) extracellular biosilicification in geothermal environments, encapsulation of Bacillus spores within a silica layer, and silicon accumulation in marine cyanobacteria. The possible contribution of bacterial biosilicification to the global silicon cycle is also discussed.

Distribution and Functional Analysis of the Two Types of 8-vinyl Reductase Involved in Chlorophyll Biosynthesis in Marine Cyanobacteria

In the chlorophyll biosynthesis pathway, the 8-vinyl group of the chlorophyll precursor is reduced to an ethyl group by 8-vinyl reductase. Two isozymes of 8-vinyl reductase have been described in oxygenic photosynthetic organisms: one encoded by BciA and another by BciB. Only BciB contains an [Fe-S] cluster and most cyanobacteria harbor this form; whereas a few contain BciA. Given this disparity in distribution, cyanobacterial BciA has remained largely overlooked, which has limited understanding of chlorophyll biosynthesis in these microorganisms. Here, we reveal that cyanobacterial BciA encodes a functional 8-vinyl reductase, as evidenced by measuring the in vitro activity of recombinant Synechococcus and Acaryochloris BciA. Genomic comparison revealed that BciB had been replaced by BciA during evolution of the marine cyanobacterium Synechococcus, and coincided with replacement of Fe-superoxide dismutase (SOD) with Ni-SOD. These findings imply that the acquisition of BciA confers an adaptive advantage to cyanobacteria living in low-iron oceanic environments.

Total synthesis and biological evaluation of oscillatoxin D, E, and F

Oscillatoxins (OTXs) and aplysiatoxins (ATXs) are biosynthetically related polyketides produced by marine cyanobacteria. We previously developed a synthetic route to phenolic O-methyl analogs of OTX-D and 30-methyl-OTX-D during collective synthesis of these natural products. According to our synthetic strategy, we achieved total synthesis of OTX-D, 30-methyl-OTX-D, OTX-E, and OTX-F by deprotecting the O-methyl group in an earlier intermediate, and determined their biological activities. Although OTX-D and 30-methyl-OTX-D have been reported to show anti-leukemic activity against L1210 cell line, we found that their cytotoxicity in vitro against this cell line is relatively weak (IC50: 29–52 μM). In contrast, OTX-F demonstrated cell line-selective anti-proliferative activity against DMS-114 lung cancer cells, which implies that OTXs target as yet unknown target molecules as part of this unique activity.