Hydrogen Peroxide Stress Induced in the Marine Cyanobacterium Synechococcus aeruginosus and Phormidium valdarianum.

Biochemical markers against hydrogen peroxide-induced oxidative stress were developed in marine cyanobacteria under standard laboratory conditions. To find out the ability to cope with different concentrations of hydrogen peroxide, two species of marine cyanobacteria including unicellular and filamentous forms were exposed for shorter duration. Synechococcus aeruginosus and Phormidium valderianum tolerated hydrogen peroxide by showing the highest growth of Superoxide dismutase in Synechococcus aeruginosus and Phormidium valderianum, catalase in Synechococcus aeruginosus, peroxidase in Synechococcus aeruginosus and Phormidium valderianum, Glutathione S-transferase in Synechococcus aeruginosus and Phormidium valderianum which were identified as biochemical markers of oxidative stress against H2O2 in marine cyanobacteria. Synechococcus aeruginosus showed new isoforms for Superoxide dismutase, catalase, peroxidase, Glutathione peroxidase, and Glutathione S-transferase and Phormidium valderianum for Superoxide dismutase, peroxidase, and Glutathione S-transferase. Synechococcus aeruginosus is suggested as the indicator species for biochemical markers against hydrogen peroxide in marine cyanobacteria. Peroxidase is suggested as biochemical enzyme marker. The present investigated on these new isoenzymes were identified as biochemical markers for oxidative stress.

Appraising the phycoremediation potential of cyanobacterial strains Phormidium and Oscillatoria for nutrient removal from textile wastewater (TWW) and synchronized biodiesel production from TWW-tolerant biomass.

In this study, phycoremediation of textile wastewater (TWW) by freshwater cyanobacterial strains such as sp., Oscillatoria sp. F01 and Oscillatoria sp. F02 was evaluated, and lipids were simultaneously extracted from biomass for biodiesel production. Onset of the study, Phormidium sp. and Oscillatoria sp. F01 has better growth rates, increased biomass production, high chlorophyll content, and efficient nutrient utilization in TWW compared to Oscillatoria sp. F02. Phormidium sp. showed 1.41 g/L dry weight, followed by Oscillatoria sp. F01 with 1.39 g/L and Oscillatoria sp. F02 with 1.02 g/L biomass. Both strains demonstrated their capability to elevate the pH level while reducing TDS and eliminating/reducing several nutrients such as nitrates, nitrites, phosphates, sulphates, sulphides, chlorides, calcium, sodium, and magnesium. Further, the total lipids extracted from the TWW-grown Phormidium sp., Oscillatoria sp. F01 and Oscillatoria sp. F02 was estimated to be 8.20, 13.70 and 11.20 %, respectively, on day 21, which was higher than the lipid content obtained from control cultures. Further, biodiesel produced from the lipids of all strains showed higher levels of C12:0, C16:0, C16:1, C18:1, C18:2, and C18:3 among all the fatty acids. Therefore, they can potentially offer a valuable source of lipids and diverse fatty acids for high-quality biodiesel production. This integrated system not only offers a solution for TWW treatment but also provides a feedstock for renewable fuel production simultaneously.

Enhancement of nitrogen cycling and functional microbial flora by artificial inoculation of biological soil crusts in sandy soils of highway slopes.

Biological soil crusts (BSCs) are common in arid and semi-arid ecosystems and enhance soil stability and fertility. Highway slopes severely deplete the soil ecological structure and soil nutrients, hindering plant survival. The construction of highway slope BSCs under human intervention is critical to ensure the long-term stable operation of the slope ecosystem. This study investigated the variation rules and interaction mechanisms between soil nutrients and microbial communities in the subsoil BSCs on highway slopes. Bacterial 16S rRNA high-throughput sequencing was employed to investigate the dynamic compositional changes in the microbial community and perform critical metabolic predictive analyses of functional bacteria. This study revealed that the total soil nitrogen increased significantly from 0.557 to 0.864 g/kg after artificial inoculation with desert Phormidium tenue and Scytonema javanicum. Actinobacteria (44-48%) and Proteobacteria (28-31%) were the dominant phyla in all samples. The abundance of Cyanobacteria, Cytophagaceae, and Chitinophagaceae increased significantly after inoculation. PICRUST analysis showed that the main metabolic pathways of soil microorganisms on highway slopes included cofactor and vitamin, nucleotide, and amino acid metabolisms. These findings suggest that the artificial inoculation with Phormidium tenue and Scytonema javanicum could alter soil microbial distribution to promote soil development on highway slopes toward nutrient accumulation.

Seawater biodesalination treatment using Phormidium keutzingianum in attached growth-packed bed continuous flow stirred tank reactor.

Water scarcity is increasing worldwide due to rising population which is creating opportunities to unlock alternative green desalination techniques for seawater, such as biodesalination. Therefore, this study presents the utilization of the Phormidium keutzingianum strain in an attached growth-packed bed reactor to treat seawater in real-time in a continuous-flow stirred tank reactor for biodesalination. Two reactors were designed and developed, in which zeolites were used as the support media for the attached growth. The experiment was conducted in an open outdoor environment with a continuous air flow rate of 3 mL/min and two hydraulic retention times (HRT) of 7 and 15 d. Parameters such as the pH, chloride ion concentration, total organic carbon (TOC), and optical density were monitored regularly. The pH change was not significant in either reactor and remained within the range of 7.25-8.0. Chloride ion removal was the most crucial component of biodesalination efficiency, with d 7 removal efficiencies of approximately 40% and 32% for reactors 1 and 2, respectively. Reactor 1 exhibited a TOC reduction of 36% within the first 10 d at a HRT of 7, and when the HRT was set to 15 d, a TOC removal efficiency of 89% was achieved on d 53. For reactor 2, a TOC removal efficiency of approximately 81% was achieved on d 11 at HRT 7, and it reduced to less than 50% at an HRT of 15. The chloride ion and TOC removal phenomena were similar in both reactors. The optical density (OD) showed low measurement recordings, ranging from 0.005 to 0.01, indicating low cell detachment in the seawater effluent. Therefore, using the attached growth method for the biodesalination of seawater is feasible. Furthermore, biomass harvesting in attached growth systems is easier than that in suspension growth systems.

Toxicological assessment of Phormidium sp. derived copper oxide nanoparticles for its biomedical and environmental applications.

Driven by the need to biosynthesized alternate biomedical agents to prevent and treat infection, copper oxide nanoparticles (CuONPs) have surfaced as a promising avenue. Cyanobacteria-derived synthesis of CuONPs is of substantive interest as it offers an eco-friendly, cost-effective, and biocompatible route. In the present study biosynthesized CuONPs were characterized and investigated regarding their toxicity. Morphological analysis using TEM, SEM and AFM showed the spherical particle size of 20.7 nm with 96% copper that confirmed the purity of CuONPs. Biogenic CuONPs with IC50 value of 64.6 µg ml-1 showed 90% scavenging of free radicals in superoxide radical scavenging assay. CuONPs showed enhanced anti-inflammatory activity by 86% of protein denaturation with IC50 value of 89.9 µg ml-1. Biogenic CuONPs exhibited significant toxicity against bacterial strains with lowest MIC value of 62.5 µg ml-1 for B. cereus and fungal strain with a MIC value of 125 µg ml-1 for C. albicans. In addition CuONPs demonstrated a high degree of synergistic interaction when combined with standard drugs. CuONPs exhibited significant cytotoxicity against non-small cell lung cancer with an IC50 value of 100.8 µg ml-1 for A549 and 88.3 µg ml-1 for the H1299 cell line with apoptotic activities. Furthermore, biogenic CuONPs was evaluated for their photocatalytic degradation potential against methylene blue dye and were able to removed 94% dye in 90 min. Free radical scavenging analysis suggested that CuONPs assisted dye degradation was mainly induced by hydroxide radicals. Biogenic CuONPs appears as an eco-friendly and cost effective photocatalyst for the treatment of wastewater contaminated with synthetic dyes that poses threat to aquatic biota and human health. The present study highlighted the blend of biomedical and photocatalytic potential of Phormidium derived CuONPs as an attractive approach for future applications in nanomedicine and bioremediation.

Temporal variation of 2-MIB and geosmin production by Pseudanabaena galeata and Phormidium ambiguum exposed to high-intensity light.

This study demonstrated the temporal variation of 2-methylisoborneol (2-MIB) and geosmin (GSM) production of two filamentous cyanobacteria species Pseudanabaena galeata (NIES-512; planktonic) and Phormidium ambiguum (NIES-2119; benthic) exposed to high light intensity (950-1000 µmol m-2  s-1 photosynthetically active radiation). The production of 2-MIB and GSM was quantified together with oxidative stress, chlorophyll content, and cellular protein content. The relative chlorophyll bleaching and cell degradations were compared through microscopic images. The 2-MIB production of P. galeata increased by over 42 ± 17% on the second day of exposure and remained leveled through the exposure period. P. ambiguum showed a continuous increase of 2-MIB until the 10th day, recording a 95 ± 4% increment. The GSM production was elevated until the fourth day of exposure by 46 ± 10% for P. galeata and by 74 ± 21% on the second day for P. ambiguum and reduced with prolonged exposure for both species. The chlorophyll content of P. galeata was reduced by 62 ± 7% on the second day, and that of P. ambiguum was reduced by 52 ± 9% on the fourth day and remained low. Protein and H2 O2 contents of both species were changed inconsistently. Exposure to high-intensity light can photobleach and deteriorate cells of both species, but elevations in odorous compounds can be expected.

Biodesalination using halophytic cyanobacterium Phormidium keutzingianum from brackish to the hypersaline water.

The biodesalination potential at different levels of salinity of Phormidium keutzingianum (P. keutzingianum) was investigated. A wide range of salinity from brackish to hypersaline water was explored in this study to ensure the adaptability of P. keutzingianum in extreme stress conditions. Brackish to hypersaline salt solutions were tested at selected NaCl concentrations 10, 30, 50, and 70 g.L-1. Chloride, pH, nitrate, and phosphate were the main parameters measured throughout the duration of the experiment. Biomass growth estimation revealed that the studied strain is adaptable to all the salinities inoculated. During the first growth phase (till day 20), chloride ion was removed up to 43.52% and 45.69% in 10 and 30 g.L-1 of salinity, respectively. Fourier transform infrared spectrometry analysis performed on P. keutzingianum showed the presence of active functional groups at all salinity levels, which resulted in biosorption leading to the bioaccumulation process. Samples for scanning electron microscopy (SEM) analysis supported with electron dispersive X-ray spectroscopy analysis (EDS) showed NaCl on samples already on day 0. This ensures the occurrence of the biosorption process. SEM-EDS results on 10th d showed evidence of additional ions deposited on the outer surface of P. keutzingianum. Calcium, magnesium, potassium, sodium, chloride, phosphorus, and iron were indicated in SEM-EDS analysis proving the occurrence of the biomineralization process. These findings confirmed that P. keutzingianum showed biomass production, biosorption, bioaccumulation, and biomineralization in all salinities; hence, the strain affirms the biodesalination process.

Microseira wollei and Phormidium algae more than doubles DBP concentrations and calculated toxicity in drinking water.

Warm weather and excess nutrients from agricultural runoff trigger harmful algal blooms, which can affect drinking water safety due to the presence of algal toxins and the formation of disinfection by-products (DBPs) during drinking water treatment. In this study, 66 priority, unregulated and regulated DBPs were quantified in chlorinated controlled laboratory reactions of harmful algae Microseira wollei (formerly known as Lyngbya wollei) and Phormidium using gas chromatography (GC)-mass spectrometry (MS). Live algae samples collected from algae-impacted lakes in South Carolina were chlorinated in both ultrapure water and real source waters containing natural organic matter. DBPs were also measured in finished water from a real drinking water plant impacted by a Microseira bloom. Results show that the presence of Microseira and Phormidium more than doubles total concentrations of DBPs formed by chlorination, with levels up to 586 µg/L formed in natural lake waters. Toxic nitrogen-containing DBPs also more than doubled in concentration, with levels up to 36.1, 3.6, and 37.9 µg/L for haloacetamides, halonitromethanes, and haloacetonitriles, respectively. In ultrapure water, DBPs also formed up to 314 µg/L when algae was chlorinated, demonstrating their ability to serve as direct precursors for these DBPs. When environmentally relevant levels of bromide and iodide were added to chlorination reactions, total DBPs increased 144, 51, and 24% for drinking water reservoir, Lake Marion and Lake Wateree Microseira respectively and 29% for Phormidium. Iodo-DBPs, bromochloroiodomethane, chloroiodoacetic acid, bromoiodoacetic acid, and diiodoacetic acid were observed in finished water from a drinking water plant impacted by Microseira, and bromochloroiodomethane and dibromoiodomethane were observed in chlorinated ultrapure water containing algae, bromide, and iodide. Notably, total calculated cytotoxicity tripled in Microseira-impacted waters and doubled for Phormidium-impacted waters. Calculated genotoxicity doubled for Microseira-impacted waters and more than doubled in Phormidium-impacted waters. Haloacetonitriles were major drivers of calculated cytotoxicity in algae-impacted waters, while haloacetic acids were major drivers of calculated genotoxicity in algae-impacted waters. These results provide the most extensive assessment of DBPs formed from chlorination of algae-impacted waters and highlight potential impacts to drinking water and human health. Results from this study are particularly applicable to drinking water treatment plants that employ pre-chlorination, which can cause the release of algal organic matter (AOM) precursors to form DBPs.

Natural Transformation, Protein Expression, and Cryoconservation of the Filamentous Cyanobacterium Phormidium lacuna.

Cyanobacteria are the focus of basic research and biotechnological projects in which solar energy is utilized for biomass production. Phormidium lacuna is a newly isolated filamentous cyanobacterium. This paper describes how new filamentous cyanobacteria can be isolated from marine rockpools. It also describes how DNA can be extracted from filaments and how the genomes can be sequenced. Although transformation is established for many single-celled species, it is less frequently reported for filamentous cyanobacteria. A simplified method for the natural transformation of P. lacuna is described here. P. lacuna is the only member of the order Oscillatoriales for which natural transformation is established. This paper also shows how natural transformation is used to express superfolder green fluorescent protein (sfGFP). An endogenous cpcB promoter induced approximately 5 times stronger expression than cpc560, A2813, or psbA2 promoters from Synechocystis sp. PCC6803. Further, a method for the cryopreservation of P. lacuna and Synechocystis sp. CPP 6803 was established, and methods for assessing motility in a liquid medium and on agar and plastic surfaces are described.

The involvement of type IV pili and the phytochrome CphA in gliding motility, lateral motility and photophobotaxis of the cyanobacterium Phormidium lacuna.

Phormidium lacuna is a naturally competent, filamentous cyanobacterium that belongs to the order Oscillatoriales. The filaments are motile on agar and other surfaces and display rapid lateral movements in liquid culture. Furthermore, they exhibit a photophobotactic response, a phototactic response towards light that is projected vertically onto the area covered by the culture. However, the molecular mechanisms underlying these phenomena are unclear. We performed the first molecular studies on the motility of an Oscillatoriales member. We generated mutants in which a kanamycin resistance cassette (KanR) was integrated in the phytochrome gene cphA and in various genes of the type IV pilin apparatus. pilM, pilN, pilQ and pilT mutants were defective in gliding motility, lateral movements and photophobotaxis, indicating that type IV pili are involved in all three kinds of motility. pilB mutants were only partially blocked in terms of their responses. pilB is the proposed ATPase for expelling of the filament in type IV pili. The genome reveals proteins sharing weak pilB homology in the ATPase region, these might explain the incomplete phenotype. The cphA mutant revealed a significantly reduced photophobotactic response towards red light. Therefore, our results imply that CphA acts as one of several photophobotaxis photoreceptors or that it could modulate the photophobotaxis response.

Hydrogen peroxide can be a plausible biomarker in cyanobacterial bloom treatment.

The effect of combined stresses, photoinhibition, and nutrient depletion on the oxidative stress of cyanobacteria was measured in laboratory experiments to develop the biomass prediction model. Phormidium ambiguum was exposed to various photosynthetically active radiation (PAR) intensities and phosphorous (P) concentrations with fixed nitrogen concentrations. The samples were subjected to stress assays by detecting the hydrogen peroxide (H2O2) concentration and antioxidant activities of catalase (CAT) and superoxide dismutase (SOD). H2O2 concentrations decreased to 30 µmol m-2 s-1 of PAR, then increased with higher PAR intensities. Regarding P concentrations, H2O2 concentrations (nmol L-1) generally decreased with increasing P concentrations. SOD and CAT activities were proportionate to the H2O2 protein-1. No H2O2 concentrations detected outside cells indicated the biological production of H2O2, and the accumulated H2O2 concentration inside cells was parameterized with H2O2 concentration protein-1. With over 30 µmol m-2 s-1 of PAR, H2O2 concentration protein-1 had a similar increasing trend with PAR intensity, independently of P concentration. Meanwhile, with increasing P concentration, H2O2 protein-1 decreased in a similar pattern regardless of PAR intensity. Protein content decreased with gradually increasing H2O2 up to 4 nmol H2O2 mg-1 protein, which provides a threshold to restrict the growth of cyanobacteria. With these results, an empirical formula-protein (mg L-1) = - 192*Log((H2O2/protein)/4.1), where H2O2/protein (nmol mg-1) = - 0.312*PAR2/(502 + PAR2)*((25/PAR)4 + 1)*Log(P/133,100), as a function of total phosphorus concentration, P (µg L-1)-was developed to obtain the cyanobacteria biomass.

Comparative growth characteristics and interspecific competitive interaction of two cyanobacteria, Phormidium autumnale and Nostoc sp. .

This study examined the growth characteristics and competitive interaction of two cyanobacteria, Phormidium autumnale GJ_2B_I1 and Nostoc sp. DS_2B_I1, which were newly isolated from a southeast river (Nakdong) during the cyanobacterial harmful algal bloom (CyanoHAB) season in Korea. As major environmental parameters, water temperature (25 and 30 °C) and alkalinity (19-78 mg CaCO3 L-1 ) and nitrate concentration (1.5-3.5 mg NO3 -N L-1 ) were selected based on the water environmental monitoring data during the CyanoHAB season. Unlike P. autumnale, Nostoc sp. has a relatively high growth rate under both monoculture and co-culture and prefers the maximum environmental conditions (30 °C and 78 mg CaCO3 L-1 ; pH 9) during the CyanoHAB season. In addition, the growth of P. autumnale is relatively unaffected by alkalinity. Nitrogen (N) stress also has a limiting effect in the interspecific interactions of both cyanobacterial strains. All other cases except for Nostoc sp. in a co-culture showed a considerable increase in growth rate with increasing N content (1.5-3.5 mg NO3 -N L-1 ), showing 20-64% under the minimum field conditions (25 °C and 19 mg CaCO3 L-1 ; pH 7) and 18-140% under the maximum field conditions. The results show that the growth of P. autumnale can be stimulated by enhanced N stress. On the other hand, Nostoc sp. is less affected by N stress compared with P. autumnale. Therefore, it has excellent potential to be a major group of CyanoHABs because of their relatively high growth rate, particularly in the range of N tested.

Bioremoval capacity of Co+2 using Phormidium tenue and Chlorella vulgaris as biosorbents.

Microalgae sorbents are microalgae that have the potential to passively bind heavy metals/contaminants to their cellular structures in a process called biosorption. This study investigates the use of two species of microalgae to remove the toxic heavy metal cobalt from aqueous solution. Two microalgae isolates, Phormidium tenue and Chlorella vulgaris, were collected from the Wadi Hanifah Stream in Riyadh, the Kingdom of Saudi Arabia. We determined the capacity of both isolates to bioremove Co+2 ions and the optimum conditions under which this occurs. The two isolates were additionally characterized by microscopic and Fourier transform infrared spectroscopy (FTIR). In the current investigation, Phormidium tenue removed 94% of Co+2 under ideal conditions of pH 6, contact duration (30 min), starting concentration (50 mgL-1) and biosorbent dose (1gL-1); while Chlorella vulgaris removed 87% of Co+2 under the same parameters except pH 5.5 and contact duration (60 min). Fourier transform infrared spectroscopy (FTIR) confirms the binding of Co+2 to the biomass, which comprises many of the functional groups. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed some alterations to the shape of algal cells and cellular components for both microalgae studied. In addition, equilibrium study by both Langmuir and Freundlich models was performed to detect the effect of certain equilibrium factors on the capacity of the biosorption mechanism. Finally, Phormidium tenue and Chlorella vulgaris were discovered to be promising microalgae for effective cobalt biosorption in aquatic conditions.

Phormidepistatin from the Cyanobacterium UIC 10484: Assessing the Phylogenetic Distribution of the Statine Pharmacophore.

A new linear lipopeptide, phormidepistatin (1), containing an epi-statine amino acid was isolated from cf. Phormidium sp. strain UIC 10484. The planar structure was elucidated by 1D and 2D NMR experimentation. The relative configuration was determined by J-based configurational analysis and the absolute configuration by advanced Marfey's analysis. Given that the statine moiety is an established pharmacophore known to inhibit aspartic proteases, phormidepistatin was evaluated against cathepsin D and displayed limited activity. With 1 containing a statine-like moiety, we sought to assess the distribution of this γ-amino acid within the phylum Cyanobacteria. In-depth MS/MS analysis identified the presence of phormidepistatin in cf. Phormidium sp. UIC 10045 and cf. Trichormus sp. UIC 10039. A structure database search identified 33 known cyanobacterial metabolites containing a statine or statine-like amino acid and, along with phormidepistatin, were grouped into 10 distinct compound classes. A phylogenetic tree was built comprising all cyanobacteria with established 16S rRNA sequences known to produce statine or statine-like-containing compound classes. This analysis suggests the incorporation of the γ-amino acid into secondary metabolites is taxonomically widespread within the phylum. Overall, it is our assessment that cyanobacteria are a potential source for statine or statine-like-containing compounds.

Metabolic Capacity of the Antarctic Cyanobacterium Phormidium pseudopriestleyi That Sustains Oxygenic Photosynthesis in the Presence of Hydrogen Sulfide.

Sulfide inhibits oxygenic photosynthesis by blocking electron transfer between H2O and the oxygen-evolving complex in the D1 protein of Photosystem II. The ability of cyanobacteria to counter this effect has implications for understanding the productivity of benthic microbial mats in sulfidic environments throughout Earth history. In Lake Fryxell, Antarctica, the benthic, filamentous cyanobacterium Phormidium pseudopriestleyi creates a 1-2 mm thick layer of 50 µmol L-1 O2 in otherwise sulfidic water, demonstrating that it sustains oxygenic photosynthesis in the presence of sulfide. A metagenome-assembled genome of P. pseudopriestleyi indicates a genetic capacity for oxygenic photosynthesis, including multiple copies of psbA (encoding the D1 protein of Photosystem II), and anoxygenic photosynthesis with a copy of sqr (encoding the sulfide quinone reductase protein that oxidizes sulfide). The genomic content of P. pseudopriestleyi is consistent with sulfide tolerance mechanisms including increasing psbA expression or directly oxidizing sulfide with sulfide quinone reductase. However, the ability of the organism to reduce Photosystem I via sulfide quinone reductase while Photosystem II is sulfide-inhibited, thereby performing anoxygenic photosynthesis in the presence of sulfide, has yet to be demonstrated.

Silver nanoparticles green synthesis via cyanobacterium Phormidium sp.: characterization, wound healing, antioxidant, antibacterial, and anti-inflammatory activities.

OBJECTIVE: Green synthesis of silver nanoparticles (AgNPs) using cyanobacterial platforms is becoming more popular nowadays. In this study, the filamentous non-heterocystous cyanobacterium Phormidium sp. was used for AgNPs production. Then, it was investigated for its antibacterial and wound-healing properties. MATERIALS AND METHODS: The cyanobacterium cultures were challenged by AgNO3, and the obtained nanoparticles were characterized using UV and FTIR spectrometric methods. The antimicrobial activity of AgNPs was scrutinized against MRSA either alone or in combination 0.5% chloramphenicol. The green synthesized AgNPs were tested for their skin wound healing activity using several wound models at different concentrations. RESULTS: The cyanobacterial culture extract showed the characteristic surface plasmon resonance peak at 440 nm for AgNPs. Different functional groups that could contribute to the reduction of Ag+ to AgNPs or the stabilization of the nanoparticles were identified by the FTIR. AgNPs potentiated the antimicrobial activity of chloramphenicol against MRSA. Green synthesized silver nanoparticles have demonstrated topical effectiveness in different wound models, including excision, incision, and burn. Significant wound improvement and the increase in wound closure rate, hydroxyproline content, and the reduction in epithelialization period confirmed the wound healing potency of AgNPs. The enzymatic antioxidant level escalation and inflammatory cytokines attenuation supported the AgNPs substantial effect on wound repairing. CONCLUSIONS: Biogenic AgNPs produced by Phormidium sp. showed significant antimicrobial together with wound healing abilities.

Bioseparation of phycocyanin from Phormidium tergestinum using an aqueous two-phase system.

This study aimed at purification of phycocyanin (PC) from Phormidium tergestinum using an aqueous two-phase system (ATPS) comprised of polyethylene glycol (PEG) and salts. The partitioning efficiency of PC in ATPS and the effect of phase composition, pH, crude loading, and neutral salts on purification factor and yield were investigated. Results showed that PC was selectively partitioned toward bottom phase of the system containing potassium phosphate. Under optimum conditions of 20% (w/w) PEG 4000, 10% (w/w) potassium phosphate, 20% (v/v) crude load at pH 7, with addition of 0.5% (w/w) NaCl, PC from P. tergestinum was partially purified up to 5.34-fold with a yield of 87.8%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the molecular weight of PC was ∼19 kDa. Results from this study demonstrated ATPS could be used as a potential approach for the purification of PC from P. tergestinum.

Screening and characterization of polyhydroxyalkanoate granules, and phylogenetic analysis of polyhydroxyalkanoate synthase gene PhaC in cyanobacteria.

Using Nile Red and BODIPY 493/503 dye-staining and fluorescence microscopy, twenty cyanobacterial strains, including ten commercially available strains and ten environmental isolates from estuaries, freshwater ponds, and lagoons, were screened for the accumulation of ecologically important and potentially biotechnologically significant carbon storage granules such as polyhydroxyalkanoates (PHA). Dye-staining granules were observed in six strains. Three Synechocystis, spp. strains WHSYN, LSNM, and CGF-1, and a Phormidium-like sp. CGFILA were isolated from environmental sources and found to produce granules of polyhydroxyalkanoate (PHA) according to PHA synthase gene (phaC) PCR screening and 1 H NMR analyses. The environmental isolate, Nodularia sp. Las Olas and commercially available Phormidium cf. iriguum CCALA 759 displayed granules but screened negative for PHA according to phaC PCR and 1 H NMR analyses. Partial polyhydroxyalkanoate synthase subunit C (phaC) and 16S rRNA gene sequences obtained from the PHA-accumulating strains and analyzed alongside publicly available phaC, phaE, 16S rRNA, and 23S rRNA data help in understanding the distribution and evolutionary history of PHA biosynthesis within the phylum Cyanobacteria. The data show that the presence of phaC is highly conserved within the genus Synechocystis, and present in at least one isolate of Phormidium. Maximum likelihood analyses and cophylogenetic modeling of PHA synthase gene sequences provide evidence of a recent horizontal gene transfer event between distant genera of cyanobacteria related to Pleurocapsa sp. PCC 7327 and Phormidium-like sp. CGFILA. These findings will help guide additional screening for PHA producers, and may explain why some Phormidium species produce PHAs, while others do not.

Revisiting high-resolution crystal structure of Phormidium rubidum phycocyanin.

The crystal structure of phycocyanin (pr-PC) isolated from Phormidium rubidum A09DM (P. rubidum) is described at a resolution of 1.17 Å. Electron density maps derived from crystallographic data showed many clear differences in amino acid sequences when compared with the previously obtained gene-derived sequences. The differences were found in 57 positions (30 in α-subunit and 27 in ß-subunit of pr-PC), in which all residues except one (ß145Arg) are not interacting with the three phycocyanobilin chromophores. Highly purified pr-PC was then sequenced by mass spectrometry (MS) using LC-MS/MS. The MS data were analyzed using two independent proteomic search engines. As a result of this analysis, complete agreement between the polypeptide sequences and the electron density maps was obtained. We attribute the difference to multiple genes in the bacterium encoding the phycocyanin apoproteins and that the gene sequencing sequenced the wrong ones. We are not implying that protein sequencing by mass spectrometry is more accurate than that of gene sequencing. The final 1.17 Å structure of pr-PC allows the chromophore interactions with the protein to be described with high accuracy.

Anti-Inflammatory Activity of Exopolysaccharides from Phormidium sp. ETS05, the Most Abundant Cyanobacterium of the Therapeutic Euganean Thermal Muds, Using the Zebrafish Model.

The Euganean Thermal District (Italy) represents the oldest and largest thermal center in Europe, and its therapeutic mud is considered a unique product whose beneficial effects have been documented since Ancient Roman times. Mud properties depend on the heat and electrolytes of the thermal water, as well as on the bioactive molecules produced by its biotic component, mainly represented by cyanobacteria. The investigation of the healing effects of compounds produced by the Euganean cyanobacteria represents an important goal for scientific validation of Euganean mud therapies and for the discovering of new health beneficial biomolecules. In this work, we evaluated the therapeutic potential of exopolysaccharides (EPS) produced by Phormidium sp. ETS05, the most abundant cyanobacterium of the Euganean mud. Specifically, Phormidium EPS resulted in exerting anti-inflammatory and pro-resolution activities in chemical and injury-induced zebrafish inflammation models as demonstrated using specific transgenic zebrafish lines and morphometric and expression analyses. Moreover, in vivo and in vitro tests showed no toxicity at all for the EPS concentrations tested. The results suggest that these EPS, with their combined anti-inflammatory and pro-resolution activities, could be one of the most important therapeutic molecules present in the Euganean mud and confirm the potential of these treatments for chronic inflammatory disease recovery.