Soil cyanobacteria isolated from the rice paddy fields of 10 different locations across Korea were evaluated by agar plate diffusion test for antifungal activity. Aqueous, petroleum ether, and methanol extracts from one hundred and forty two cyanobacterial strains belonging to the 14 genera were examined for antifungal properties against seven phytopathogenic fungi causing diseases in hot pepper (Capsicum annuum L). Of total cyanobacteria, nine cyanobacteria (6.34%) exhibited antifungal effects. The nine cyanobacteria selected with positive antifungal activities were two species of Oscillatoria, two of Anabaena, three of Nostoc, one of Nodularia, and one of Calothrix. Alternaria alternata and Botrytis cinerea were inhibited by nine and eight species of cyanobacteria, respectively. Rhizopus stolonifer was suppressed by only methanol extract of Nostoc commune FK-103. In particular, Nostoc commune FK-103 and Oscillatoria tenuis FK-109 showed strong antifungal activities against Phytophthora capsici. Their antifungal activity at the late exponential growth phase is related to the growth temperature and not associated with the growth parameters such as cell biomass and chlorophyll-alpha concentration. The high inhibition levels of antibiotics were 22.5 and 31.8 mm for N. commune FK-103 and O. tenuis FK-109, respectively. The optimal temperature for antibiotic productivity was 35degrees C.
Agar ; Alternaria ; Anabaena ; Anti-Bacterial Agents ; Biomass ; Botrytis ; Cyanobacteria* ; Diffusion ; Efficiency ; Ether ; Fungi* ; Korea ; Mass Screening* ; Methanol ; Nodularia ; Nostoc ; Nostoc commune ; Oscillatoria ; Petroleum ; Phytophthora ; Plants* ; Rhizopus ; Soil*

The present study was undertaken to explore the inhibitory effect of cyanobacterial extracts of Nostoc commune FA-103 against the tomato-wilt pathogen, Fusarium oxysporum f. sp. lycopersici. In an optimal medium, cell growth, antifungal activity, and antifungal compound production could be increased 2.7-fold, 4.1-fold, and 13.4-fold, respectively. A crude algal extract had a similar effect as mancozeb at the recommended dose, both in laboratory and pot tests. In vitro and in vivo fungal growth, spore sporulation and fungal infection of wilt pathogen in tomato seeds were significantly inhibited by cyanobacterial extracts. Nostoc commune FA-103 extracts have potential for the suppression of Fusarium oxysporum f. sp. lycopersici.
Azepines ; Cyanobacteria ; Fluoroquinolones ; Fusarium ; Lycopersicon esculentum ; Maneb ; Nostoc commune ; Seeds ; Spores ; Zineb

Gas vesicles are a unique class of gas-filled protein nanostructures which are commonly found in cyanobacteria and Halobacterium. The gas vesicles may scatter sound waves and generate harmonic signals, which enabled them to have the potential to become a novel ultrasound contrast agent. However, the current hypertonic cracking method for isolating gas vesicles contains tedious operational procedures and is of low yield, thus not suitable for large-scale application. To overcome these technical challenges, we developed a rapid and efficient method for isolating gas vesicles from Microcystis. The new H₂O₂-based method increased the yield by three times and shortened the operation time from 24 hours to 7 hours. The H₂O₂ method is not only suitable for isolation of gas vesicles from laboratory-cultured Microcystis, but also suitable for colonial Microcystis covered with gelatinous sheath. The gas vesicles isolated by H₂O₂ method showed good performance in ultrasound contrast imaging. In conclusion, this new method shows great potential for large-scale application due to its high efficiency and wide adaptability, and provides technical support for developing gas vesicles into a biosynthetic ultrasonic contrast agent.
Contrast Media ; Cyanobacteria ; Hydrogen Peroxide ; Microcystis ; Proteins/chemistry*

OBJECTIVEAttempting to isolate and cultivate the microcytin-RR-producing cyanobacteria from natural blooms as well as to further investigate some characteristics of their growth and metabolite toxicity.

METHODSCapillary-pipette method was used to isolate wild Microcystis strains collected from eutrophicated lakes. The isolated strains were cultured in BG11 media at (25 ± 1) °C, under 2 000 lx illumination of fluorescent light with a light-dark rhythm of 12-12 h. The growth curve was observed by measuring optical density of culture suspension, toxin-related genes and the metabolite toxins were identified separately by PCR and HPLC, and its acute toxicity was carried out by orally administered toxins to Kunming (KM) mice.

RESULTSOne of five toxigenic strains from 198 collected samples was confirmed to be a MC-RR producing blue-green alga by existing two specific toxin-synthesized enzyme genes and showing specific chromatographic peak of the toxin compared with standard MC-RR through both PCR and HPLC methods. The toxic strain was classified as Microcystin aeruginosa by morphologic and phylogenetic tree analysis. The growth length of the strain lasted nearly 81 days with 55-60 days' exponential phase and the maximal concentration of 5.52 × 10⁷ cell/ml. The LD50 of the MC-RR to the KM mice ranged from 10.75 mg/kg to 13.45 mg/kg of body weight. As a result of the acute toxicity, the enzymatic indexes in serum such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) were significantly higher than those in the control group. The levels of ALT, AST, ALP and LDH in the treated group at 45 min were (157.08 ± 20.38), (333.00 ± 68.53), (392.70 ± 89.59) and (1 071.13 ± 160.22) U/L respectively, and at 4 h were (514.68 ± 156.87), (593.15 ± 40.41), (618.55 ± 208.76) and (2 281.72 ± 866.67) U/L respectively, and meanwhile the values of ALT, AST, ALP and LDH in the control group were (40.30 ± 4.89), (142.70 ± 26.59), (56.90 ± 11.89) and (509.50 ± 94.75) U/L separately (t values at 45 min were -11.20, -5.77, -7.38, -6.60 respectively, and at 4 h were -6.04, -20.21, -5.35, -4.07 respectively, P values were all <0.01). The liver coefficient in the treated group at 45 min and 4 h were 6.855 ± 0.225 and 8.409 ± 0.276, significantly higher than that (5.784 ± 0.286) in the control group (t values were -3.96 and -12.22, P values were both <0.01). The histopathological changes of liver were hyperemia obviously.

CONCLUSIONIsolated from the bloom waters, a strain of Microcystis aeruginosa is obtained with characteristics of longer growth duration, positive microcystin synthetase genes, and dominant production of MC-RR. The LD50 of the extracted MC-RR administered by oral route to mice is (12.10 ± 1.35) mg/kg of body weight, and liver is the target organ of MC-RR. The existence and potential risk of MC-RR in China cannot be ignored.

Animals ; China ; Chromatography, High Pressure Liquid ; Cyanobacteria ; Hyperemia ; Lakes ; Liver ; Mice ; Microcystins ; Microcystis ; Phylogeny

The bioactive protein-phycocyanin and all the proteins of Spirulina Platensis were isolated and purified. Photo-reactive proteins were synthesized by coupling the proteins with (N-(4-azidobenzoyloxy)succinimide) and were spread onto the 24-well cell culture polystyrene plate. Then the coated surface was exposed to ultraviolet irradiation for chemical fixation of proteins via the conversion of the phenylazido group to the highly reactive phenyl-nitrene which spontaneously formed covalent bonds with neighboring hydrocarbons. On these proteins-immobilized polystyrene plates, the liver cancer cells 7402 were cultured under the serum-free conditions, and the inhibition activity on proliferation of liver cancer cells was investigated and analyzed.
Animals ; Bacterial Proteins ; chemistry ; pharmacology ; Biocompatible Materials ; pharmacology ; Cell Division ; drug effects ; Cyanobacteria ; chemistry ; Liver Neoplasms ; pathology ; Photochemistry ; Polystyrenes ; chemistry ; Spirulina ; Succinimides ; chemistry ; Tumor Cells, Cultured

PURPOSE: It has been reported that Spirulina, a blue-green algae with potent antioxidant properties, affords significant protection against inflammation and fibrosis in the liver in vivo. The aim of the present study was to establish the possible protective role of C-phycocyanin, one of the active ingredients of Spirulina, in an experimental model of fibrosis in the kidney. METHODS: The study was carried out using male C57BL6 mice. Mice were divided into the following four groups: sham-operated group; C-phycocyanin (PC)-treated sham group; unilateral ureteral obstruction (UUO) group; and PC with UUO group. We evaluated renal TGF-beta mRNA, MCP-1, and osteopontin using real-time RT PCR. We evaluated renal TGF-beta, alpha-SMA, and CD68 by immunohistochemistry. We recorded light microscopic findings of kidney specimens. RESULTS: PC significantly decreased the expression of MCP-1 and alpha-SMA mRNA. Renal gene levels of expression of TGF-beta, MCP-1, and osteopontin in the UUO group were significantly higher than the sham-operated group (p<0.01). The levels of expression of TGF-beta, MCP-1, and osteopontin mRNA of kidneys in the PC-treated UUO group were significantly lower than the untreated UUO group (p< 0.05). The magnitude of expression of TGF-beta and alpha-SMA protein in the kidneys of the PC-treated UUO group was significantly less than the untreated UUO control group (p<0.05). CONCLUSION: The results of the present study suggest that PC has anti-inflammatory and anti-fibrotic effects in an experimental UUO murine model.
Animals ; Cyanobacteria ; Fibrosis ; Humans ; Immunohistochemistry ; Inflammation ; Kidney ; Light ; Liver ; Male ; Mice ; Models, Theoretical ; Osteopontin ; Phycocyanin ; Polymerase Chain Reaction ; RNA, Messenger ; Salicylamides ; Spirulina ; Transforming Growth Factor beta ; Ureteral Obstruction

Cyanobacteria is one of the promising microbial chassis in synthetic biology, which serves as a typical host for light-driven production. With the gradual depletion of fossil resources and intensification of global warming, the research on cyanobacterial cell factory using CO2 as carbon resource is ushering in a new wave. For a long time, research focus on cyanobacterial cell factory has mainly been the production of energy products, such as liquid fuels and hydrogen. One of the critical bottlenecks occurring in cyanobacterial cell factory is the poor economic performance, which is mainly caused by the inherent inefficiency of cyanobacteria. The problem is particularly prominent for these extremely cost-sensitive energy products. As an indispensable basis for modern industry, polymer monomers belong to the bulk chemicals with high added value. Therefore, increasing attention has been focused on polymer monomers which are superior in overcoming the economic barrier in commercialization of cyanobacterial cell factories. Here, we systematically review the progress on the production of polymer monomers using cyanobacteria, including the strategies for improving production, and the related technologies for the application of this important microbial cell factory. Finally, we summarize several issues in cyanobacterial synthetic biology and proposed future developing trends in this field.
Cyanobacteria ; Macromolecular Substances ; Polymers ; Synthetic Biology

Biorefinery technologies provide promising solutions to achieve sustainable development facing energy and environment crisis, while abundant sugar feedstock is an essential basis for biorefinery industries. Photosynthetic production of sucrose with cyanobacteria is an alternative sugar feedstock supply route with great potentials. Driven by solar energy, cyanobacteria photosynthetic cell factory could directly convert carbon dioxide and water into sucrose, and such a process could simultaneously reduce carbon emissions and supply sugar feedstocks. Here we introduced the history and updated the state-of-the-art on development of cyanobacteria cell factories for photosynthetic production of sucrose, summarized the progress and problems on mechanisms of sucrose synthesis, metabolic engineering strategies and technology expansions, and finally forecasted the future development direction in this area.
Carbon Dioxide ; Cyanobacteria ; Metabolic Engineering ; Photosynthesis ; Sucrose

Cyanobacteria are the only prokaryotes capable of oxygenic photosynthesis, which have potential to serve as "autotrophic cell factories". However, the synthesis of biofuels and chemicals using cyanobacteria as chassis are suffered from poor stress tolerance and low yield, resulting in low economic feasibility for industrial production. Thus, it's urgent to construct new cyanobacterial chassis by means of synthetic biology. In recent years, adaptive laboratory evolution (ALE) has made great achievements in chassis engineering, including optimizing growth rate, increasing tolerance, enhancing substrate utilization and increasing product yield. ALE has also made some progress in improving the tolerance of cyanobacteria to high light intensity, heavy metal ions, high concentrations of salt and organic solvents. However, the engineering efficiency of ALE strategy in cyanobacteria is generally low, and the molecular mechanisms underpinning the tolerance to various stresses have not been fully elucidated. To this end, this review summarizes the ALE-associated technical strategies and their applications in cyanobacteria chassis engineering, following by discussing how to construct larger ALE mutation library, increase mutation frequency of strains and shorten evolution time. Moreover, exploration of the construction principles and strategies for constructing multi-stress tolerant cyanobacteria, and efficient analysis the mutant libraries of evolved strains as well as construction of strains with high yield and strong robustness are discussed, with the aim to facilitate the engineering of cyanobacteria chassis and the application of engineered cyanobacteria in the future.
Technology ; Photosynthesis/genetics* ; Cyanobacteria/genetics* ; Light ; Biofuels

In the forensic practice, the reliability of diatom test as a supportive measure to diagnose drowning is still disputed, from trustworthy to worthless. Some of the reason for the controversy is low sensitivity of the test, possibility of postmortem contamination and the detection of diatom in the tissues of non-drowned body. However, there is a variation of the diatom flora by season and by locale and it is strongly correlated with the frequency of positive diatom test outcomes. Therefore, if there is a profile of the diatom flora at a site, it can be compared with the diatom genera found in tissues of the immersed bodies, and also the test result can be predicted or verified. On each season, at three aquatic locations where drowning victims are often found, the author collected water samples and examined the plankton species of the samples, including dominant species and total number of plankton by site and by season. The examination result showed 16 species of diatoms, 20 species of green algae, 6 species of cyanobacteria, and 6 species of other algae. There is an enormous difference of population of algae by site(39 cells ~ 37,180 cells), but conspicuous periodicity of types and numbers of algae is not noted by season and by depth.
Chlorophyta ; Cyanobacteria ; Diatoms ; Drowning ; Periodicity ; Plankton ; Seasons ; Water