Cyanobacterium Phormidium Research Articles

Photosystems and photoreceptors in cyanobacterial phototaxis and photophobotaxis.

Cyanobacteria move by gliding motility on surfaces toward the light or away from it. It is as yet unclear how the light direction is sensed on the molecular level. Diverse photoreceptor knockout mutants have a stronger response toward the light than the wild type. Either the light direction is sensed by multiple photoreceptors or by photosystems. In a study on photophobotaxis of the filamentous cyanobacterium Phormidium lacuna, broad spectral sensitivity, inhibition by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and a highly sensitive response speaks for photosystems as light direction sensors. Here, it is discussed whether the photosystem theory could hold for phototaxis of other cyanobacteria.

Identification of Phormidium sp, (kützing ex Gomont 1892): a potential exopolymer for effective bioremediation

The autotrophic cyanobacterium Phormidium sp. is filamentous, blue-green, sheath-prominent, and trichome-constricted. DNA barcoding of the 16S rRNA sequence was submitted to NCBI-GenBank under the accession number MW436689, with a similarity of 97–99% with varied sequences. The Phormidium sp. barcode region had a high G + C content (52.7%). An investigation is underway to extract and characterize exocellular polymeric substances from Phormidium sp. (EPS-P) for efficacy analysis. FTIR, GC-MS, and NMR were used to characterize (EPS-P). FTIR suggests the presence of hydroxy groups (O-H moieties) and amine salts (N-H). GCMS shows D-galactose, L-rhamnose, D-mannose, uronic acid, and D-glucuronic acid. The specific chemical shifts could be identified in the 1H NMR spectra. EPS has been used in a variety of industrial and environmental applications. The ability to emulsify EPS-P (0.1%) was analyzed with various oils. The emulsifying index (EI) was observed to be gingelly oil > brake oil > neem oil > coconut oil > petrol oil > diesel oil (EI24-EI120 hours). EPS-P performed bio-flocculating activity at various concentrations (10-50 mg mL1). The flocculating activity of EPS-P shows 89.5% at 50 mg ml−1. The EPS-P could be an excellent candidate for bio-flocculation and bio-emulsification aspects that are also eco-friendly.

Photophobotaxis in the filamentous cyanobacterium Phormidium lacuna: Mechanisms and implications for photosynthesis-based light direction sensing.

Cyanobacterium Phormidium lacuna filaments move from dark to illuminated areas by twitching motility. Time-lapse recordings demonstrated that this photophobotaxis response was based on random movements with movement reversion at the light-dark border. The filaments in the illuminated area form a biofilm attached to the surface. The wild-type and the pixJ and cphA mutants were investigated for photophobotaxis at diverse wavelengths and intensities. CphA is a cyanobacterial phytochrome; PixJ is a biliprotein with a methyl-accepting chemotaxis domain and is regarded as a phototaxis photoreceptor in other species. The cphA mutant exhibited reduced biofilm surface binding. The pixJ mutant was characterized as a negative photophobotaxis regulator and not as a light direction sensor. 3-(3,4-dichlorophenyl)1,1-dimethylurea (DCMU) blocks electron transfer in PS II. At concentrations of 100 and 1000 μM DCMU, photophobotaxis was inhibited to a greater extent than motility, suggesting that PSII has a role in photophobotaxis. We argue that the intracellular concentrations of regular photoreceptors, including CphA or PixJ, are too small for a filament to sense rapid light intensity changes in very weak light. Three arguments, specific inhibition by DCMU, broad spectral sensitivity, and sensitivity against weak light, support photosynthesis pigments for use as photophobotaxis sensors.

Effect of a dark-colored substrate on the production of phycocyanin by the cyanobacterium Phormidium sp

As the biotechnological production of valuable compounds has recently gathered research interest, more and more photosynthetic microorganisms are being examined for the synthesis of proteins, fatty acids, pigments, and other biopolymers. In this work, a local isolate (lagoons of Western Greece), of the blue-green cyanobacterium Phormidium sp., was evaluated. Its cultures were considered to be promising for the recovery of the phycobiliprotein, called phycocyanin, even during mixotrophic growth. Interestingly, phycocyanin accumulation was favored by substrates with a low organic load. In order to minimize substrate cost, anaerobic digestion effluent was used as a nutrient and organic carbon source, replacing a synthetic medium containing glucose, to meet the cyanobacterium’s nutrient needs. The results from the cultures containing liquid digestate were surprising, as its addition at low concentrations not only allowed Phormidium sp. to grow but also enhanced the phycocyanin synthesis. The experiments that exhibited a notable phycocyanin production showed a final biomass concentration that barely exceeded 0.7 g L−1 regardless of the nature of the substrate. When Phormidium sp. was inoculated in a pure synthetic medium with 1 g L−1 of glucose, phycocyanin concentration approached 10 mg L−1, while it was measured being 1.75 times higher in the culture containing 10% v/v anaerobic effluent, due to greater cellular accumulation. The present work comes as evidence of the successful bioremediation of digestate accompanied by the production of a high added-value pigment, leading to the removal of organic carbon, total nitrogen, and phosphorous in percentages of 60%, 90%, and 40% respectively.

Tradescantia-Based Test Systems Can Be Used for the Evaluation of the Toxic Potential of Harmful Algal Blooms

Harmful algal blooms (HABs) are overgrowths of toxic strains of algae (diatoms, green) and cyanobacteria (blue-green algae). While occurring naturally, human-induced environmental changes have resulted in more frequent occurrences of such blooms worldwide. Meantime, the ecotoxicological risk of HABs is rarely evaluated by means of standard test methods. For the first time, the genotoxic potential of the HAB event 2020 was assessed using two different Tradescantia-based test systems (Trad-SHM and Trad-MN, 24-h exposure). An integrated analysis of biological (algal abundance) and ecotoxicological (testing) data revealed linkages among algal proliferation, changes in Tradescantia stamen hairs (mutations and suppressed growth) and chromosomal aberrations during microsporogenesis (appearance of micronuclei) that were likely to be caused by toxic algal groups. Green alga Botryococcus braunii and the cyanobacterial species Anabaena and Oscillatoria could suppress stamen hair growth; Cyanobacteria Phormidium and Aphanothece sp. could trigger mutations in stamen hairs (appearance of pink and colorless cells); and Oscillatoria sp. could be responsible for the occurrence of chromosomal damage. Diatom proliferation in the spring was not related to the genotoxic response in Tradescantia. Both tests, the Trad-SHM and Trad-MN, are suitable for the evaluation of the toxic potential of HABs.

Assessment of optimal growth conditions for biomass and exopolysaccharides production in the thermotolerant cyanobacterium Phormidium sp. ETS-05

AbstractPhormidium sp. ETS-05 is one of the target cyanobacteria species conferring anti-inflammatory properties to the therapeutic muds applied by spas of the Euganean Thermal District (Italy) to treat arthro-rheumatic pathologies. Beneficial mud is prepared by spas following a traditional method, called maturation, leading to the growth of a specific microbiota on natural raw clay irrigated by flowing thermal water at 37–47 °C for about two months. The effectiveness of the mud is related to heat, electrolytes and bioactive molecules synthesized by the microbiota. A clear role in the anti-inflammatory activity of muds has been demonstrated for the exopolysaccharides, EPS, produced by the entire microbiota and Phormidium sp. ETS-05. Considering the interest in this species, we assessed its optimal growth conditions to obtain the higher EPS production in relation to temperature, light spectra, and intensity and nitrogen availability. The production of biomass and pigments was also taken into account, as other high-value compounds can be obtained in parallel with EPS. We found that exposure to a temperature of 45 °C under white light at 100 µmol photons m−2 s−1 is optimal to reach the highest biomass (1.13 g L−1) and an average production of 75 mg gDW−1 phycocyanin and of 150 mg gDW−1 EPS for Phormidium sp. ETS-05 cultured in lab-scale photobioreactors for 9 days. Putative genes linked with EPS assembly and export have also been identified in its genome, some of which have been investigated for their expression levels, opening up the possibility of biotechnologically boost EPS production.

A novel actinomycete Streptomyces enissocaesilis exhibiting algicidal activity against the toxic cyanobacterium Phormidium angustissimum

Harmful cyanobacterial blooms that occur in freshwater can produce hazardous cyanotoxins as contaminants that threaten ecosystems, aquatic organisms, and human health. In the present study, the actinobacterium Streptomyces enissocaesilis, strain M35, isolated from soils, exhibited the strongest algicidal activity against the toxic cyanobacterium Phormidium angustissimum TISTR 8247. To improve the P. angustissimum removal efficiency of strain M35, the optimum carbon and nitrogen sources were determined as starch and yeast extract, respectively. Response surface methodology (RSM) using the Box-Behnken design (BBD) revealed that the optimal independent parameters among the culture medium conditions for enhancing the algicidal activity of strain M35 were 21.5g/L starch, 0.57g/L yeast extract, and a pH value of 8.00. The Phormidium sp. removal efficiency increased notably from 80.8 to 94.4% under the optimum conditions. In a batch experiment, the removal of P. angustissimum in an internal airlift loop (IAL) bioreactor containing immobilized strain M35 on a plastic medium indicated a high anti-Phormidium activity of 94.8%, whereas in a continuous system, strain M35 exhibited a removal efficiency of 85.5%. This study revealed that this actinobacterium could potentially be utilized to remove the toxic cyanobacterium Phormidium from water.

Statistical Optimization and Downstream Processing of C‐Phycocyanin from Phormidium valderianum

AbstractC‐Phycocyanin (C‐PC), a blue pigment from cyanobacteria, is a promising replacement for harmful synthetic food colors. The cyanobacterium Phormidium valderianum is suggested as an alternative source for C‐PC to the frequently utilized Spirulina. The importance of harvest time is emphasized as a key variable in the optimization process. To increase the C‐PC concentration, the effects and optimal values of sonication time, harvesting time, and pH levels were evaluated using response surface methodology. C‐PC extracted by ultrasonication was adsorbed by activated charcoal and polyvinylidene fluoride (PVDF) membrane filtration to achieve food‐grade purity. The product now has a shelf life of more than nine months and better thermal stability of 75 ± 2 °C.

Development of marine activated algal-bacterial granule: A novel replacement to the conventional algal remediation processes

A self-sustained waste treatment technology entails the integration of various cultivation and harvesting processes cost-effectively. Activated algae are a unique microalgae-based technological platform with diverse applications and superior performance compared to the conventional methodologies. An attempt has been made to develop marine activated algae using targeted microalgal species (Synechococcus elongates, Chroococcus minor, Chroococcus sp., Phormidium sp., and Spirulina platensis) and activated bacterial sludge cultured in a customized sequential batch reactor (SBR). The activated marine granules attained a sturdy structural configuration with further inclusion of filamentous cyanobacterium Phormidium sp. A complete marine activated algal-bacterial granule was formed in 40 days however; the maturation phase was prolonged to 90 days for its robustness. A progressive decline in turbidity and dissolved solids accompanied by the maturation of the granules further affirmed its remediation potential. Pronounced reduction in total nitrogen and phosphorus levels (∼75 %) was observed from the wastewater growth medium. The matured marine granules rapidly removed the enhanced nitrate concentrations (500 mg L−1 of NO3 in 32 h) from the simulated wastewater accompanied by rapid increase in the settling velocity (5.8 m/h) suggesting that granules can be harvested precipitously. The present work is a novel attempt using specific marine algae and is a viable bio-remediating technology with minimal cost inputs for sustainable treatment of complex loadings. Extracellular Polymeric Substances (EPS) secretion and quorum sensing (QS) mediated interaction among the algal-bacterial relationship widely influenced the community organization, population structure, etc., and was instrumental in the granule formation.

Cleaning of Phototrophic Biofilms in a Show Cave: The Case of Tesoro Cave, Spain

Show caves have different grades of colonization by phototrophic biofilms. They may receive a varied number of visits, from a few thousand to hundreds of thousands of visitors annually. Among them, Tesoro Cave, Rincon de la Victoria, Spain, showed severe anthropic alterations, including artificial lighting. The most noticeable effect of the lighting was the growth of a dense phototrophic community of cyanobacteria, algae and bryophytes on the speleothems, walls and ground. The biofilms were dominated by the cyanobacterium Phormidium sp., the chlorophyte Myrmecia israelensis, and the rhodophyte Cyanidium sp. In many cases, the biofilms also showed an abundance of the bryophyte Eucladium verticillatum. Other cyanobacteria observed in different biofilms along the cave were: Chroococcidiopsis sp., Synechocystis sp. and Nostoc cf. edaphicum, the green microalgae Pseudococcomyxa simplex, Chlorella sp. and the diatom Diadesmis contenta. Preliminary cleaning tests on selected areas showed the effectiveness of hydrogen peroxide and sodium hypochlorite. A physicochemical treatment involving the mechanical removal of the thickest layers of biofilms was followed by chemical treatments. In total, 94% of the surface was cleaned with hydrogen peroxide, with a subsequent treatment with sodium hypochlorite in only 1% of cases. The remaining 5% was cleaned with sodium hypochlorite in areas where the biofilms were entrapped into a calcite layer and in sandy surfaces with little physical compaction. The green biofilms from the entire cave were successfully cleaned.

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.

Identification of the key functional genes in salt-stress tolerance of Cyanobacterium Phormidium tenue using in silico analysis.

The online version contains supplementary material available at 10.1007/s13205-021-03050-w.

Culture Growth of the Cyanobacterium Phormidium sp. in Various Salinity and Light Regimes and Their Influence on Its Phycocyanin and Other Pigments Content

A strain of the filamentous non N-fixing cyanobacterium Phormidium sp. isolated from the Messolonghi (W. Greece) saltworks, was cultured in the laboratory at six different combinations of salinity (20-40-60 ppt) and illumination (low-2000 lux and high-8000 lux). At salinities of 60 and 40 ppt and in high illumination (XL-8000 lux), the growth rate (μmax) presented the highest values (0.491 and 0.401, respectively) compared to the corresponding at 20 ppt (0.203). In general and at all salinities, the higher illumination (XL) gave the highest growth rates and shorter duplication time (tg) in comparison to the lower illumination (L). On the contrary, phycocyanin, phycoerythrin and allophycocyanin production was extremely increased in the lower illumination (L) in all salinities, from ~14 fold at 40 and 60 ppt to 269 fold at 20 ppt of those corresponding to higher illumination (XL). Similar analogies were also recorded for the other two billiproteins. Chlorophyll-a content was also higher in lower illumination at all salinities in contrast to total carotenoids that did not exhibit such a pattern. The high growth rate and high phycocyanin content along with the rapid sedimentation of its cultured biomass can set this marine Phormidium species as a promising candidate for mass culture.

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

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. 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. 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. Biogenic AgNPs produced by Phormidium sp. showed significant antimicrobial together with wound healing abilities.

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.

Prebiotic-Inulin as the Major Water Soluble Carbohydrates from Marine Cyanobacterium Phormidium formosum

Prebiotic-Inulin as the Major Water Soluble Carbohydrates from Marine Cyanobacterium Phormidium formosum

Calibration Curves of Culture Density Assessed by Spectrophotometer for Three Microalgae (Nephroselmis sp., Amphidinium carterae and Phormidium sp.)

This study concerns the finding of an effective operational equation relating the measured absorpbance (or O.D. - optical density) in a spectrophotometer of the suspended cells of microalgae to their cell density (c.d.) in culture in order to construct calibration curves for use in culture operations. The microalgae examined were the chlorophyte Nephroselmis sp., the dinophyte Amphidinium carterae and the filamentous cyanobacterium Phormidium sp. Wavelengths of 430 and 680 nm were selected that correspond to chlorophyll-a peaks of their absorption spectra were used and additionally 750 and 570 nm where absorbance was not peaked. From all equations extracted best fitness with strong predictive values were those of a logarithmic type: O.D.=0,9328*ln(c.d.)-14,108 (R2=0,9943) at 680 nm for Nephroselmis, a power equation: O.D.=0,0000009*(c.d.)0,9195 (R2=0,9936) at 680 nm for Amphidinium and a polynomial second order: O.D.=0,9869(c.d.)2+2,4393(c.d.)+0,2666 (R2=0,9737) at 570 nm for Phormidium.

Antimicrobial screening of silver nanoparticles synthesized by marine cyanobacterium Phormidium formosum

Nanoparticles are widely used in various fields such as electronics, cosmetics, water purification, biomedical and biotechnology. Biosynthesis of nanoparticles using biological agents have gained much attention in the area of nanotechnology in the last few decades because of cost effective, non-toxic, and eco-friendly. Algae have been used to reduce metal ions and subsequently for the biosynthesis of nanoparticles. Silver nanoparticles (AgNPs) have been biosynthesized by Phormidium formosum isolated from Mediterranean Sea coast Egypt in an aqueous system. An aqueous solution of silver ions was treated with alive biomass of P. formousm for the formation of AgNPs. The physio-chemical properties of synthesized silver nanoparticles were studied using analytical techniques such as UV-Vis spectrophotometer, transmission electron microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). The antimicrobial effect of synthesized silver nanoparticles was also tested on several microorganisms by measuring the inhibition zone. These nanoparticles showed an absorption peak at λmax 437 nm in the UV-visible spectrum, corresponding to the Surface Plasmon Resonance of AgNPs. The transmission electron micrographs of nanoparticles in an aqueous solution showed production of silver nanoparticles synthesized by P. formosum. The obtained AgNPs are spherical in shape with a size ranging from 1.83 nm to 26.15nm. The Fourier transmittance infrared spectrum (FTIR) confirms the presence of bio component in alive biomass of P. formosum which was responsible for the nanoparticles synthesis. The antimicrobial test revealed that AgNPs synthesized by P. formosum is capable to inhibit the growth of microorganisms. The results confirmed that AgNPs can act as a powerful antimicrobial agent against fish and human pathogens.

Natural transformation of the filamentous cyanobacterium Phormidium lacuna.

Research for biotechnological applications of cyanobacteria focuses on synthetic pathways and bioreactor design, while little effort is devoted to introduce new, promising organisms in the field. Applications are most often based on recombinant work, and the establishment of transformation can be a risky, time-consuming procedure. In this work we demonstrate the natural transformation of the filamentous cyanobacterium Phormidium lacuna and insertion of a selection marker into the genome by homologous recombination. This is the first example for natural transformation filamentous non-heterocystous cyanobacterium. We found that Phormidium lacuna is polyploid, each cell has about 20–90 chromosomes. Transformed filaments were resistant against up to 14 mg/ml of kanamycin. Formerly, natural transformation in cyanobacteria has been considered a rare and exclusive feature of a few unicellular species. Our finding suggests that natural competence is more distributed among cyanobacteria than previously thought. This is supported by bioinformatic analyses which show that all protein factors for natural transformation are present in the majority of the analyzed cyanobacteria.

Elevated CO2 impact on growth and lipid of marine cyanobacterium Phormidium valderianum BDU 20041– towards microalgal carbon sequestration

Abstract The growth of marine cyanobacteria at elevated CO2 levels is one of the feasible means to bioremediate the greenhouse gases. The present paper describes a marine filamentous cyanobacterium Phormidium valderianum BDU 20041 that can grow at elevated CO2 levels (15%), simulated and actual flue gas. Compared to ambient air and other tested CO2 concentrations, 3% CO2 showed higher biomass productivity, growth rate and carbon fixation rate. The organism was able to tolerate 15% CO2 and the simulated flue gas conditions making it a strong candidate for microalgal carbon capture. The lipid content of P. valderianum BDU 20041 at 15% CO2, simulated and actual flue gas conditions was higher than the ambient air. The conditions tested, i.e. 15% CO2, simulated and real flue gas show that this organism could be a potential entity in curbing carbon emission and a plausible biodiesel feedstock through hydrothermal liquefaction.