Composición bioquímica y toxicidad de colonias comestibles de la cianobacteria andina Nostoc sp. Llayta / Biochemical composition and toxicity of edible colonies of the cyanobacterium Nostoc sp. Llayta

RESUMEN Llayta es el nombre asignado a la biomasa seca de macrocolonias de una cianobacteria filamentosa, clasificada como Nostoc sp. Llayta crece en humedales andinos de Sudamérica y ha sido considerada como un ingrediente alimenticio desde tiempos precolombinos. Este estudio pretende contribuir a la definición de la calidad nutritiva de la Llayta, proporcionando información sobre su composición bioquímica e identificar aspectos críticos de interés toxicológico. Los resultados mostraron que el 60% del total de sus aminoácidos son indispensables, contenía un 2% de lípidos totales, 32% del total de ácidos grasos eran poliinsaturados, la vitamina E fue la más abundante (4,3 mg%), el contenido de polifenoles totales es 64 mg equivalentes de ácido gálico, su actividad antioxidante es 17,4 μmoles equivalentes de Trolox, la fibra total fue el 56% del peso seco y presentó un contenido promedio de arsénico total de 9,2 ± 5,4 ppm. Esta cianobacteria no es productora de microcistina, por lo que las colonias de la Llayta podrían considerarse inocua para el consumo humano.

ABSTRACT Llayta is the name assigned to the dry biomass of macrocolonies of a filamentous cyanobacterium classified as Nostoc sp. Llayta grows in the Andean wetlands of South America and has been considered a food ingredient since pre-Columbian times. This work is an effort to contribute to define the nutritional quality of Llayta providing information on its biochemical composition and to identify key toxicological aspects. The results indicated that 60% of its aminoacids were indispensable, total lipids were 2% of dry weight, polyunsaturated fatty acids were 32% of total fatty acids, vitamin E was the most abundant (4.3 mg%), total polyphenols were 64 mg (equivalent to galic acid), antioxidant activity was 17.4 μmoles (equivalent to Trolox), total fiber was 56% of dry weight and accumulated 9.2 ± 5.4 ppm of total arsenic. Since Nostoc sp. Llayta is a cyanobacterium strain that does not synthesize the cyanotoxin microcystin, the Llayta colonies can be considered innocuous for human consumption.

The Lichen Genus Sticta in South Korea

Sticta (Schreber.) Ach. is one of the common lichen genera in tropical and subtropical regions, but not in the Korean Peninsula. For almost two decades, no detailed taxonomic or revisionary study has been done on this genus. This study was based on the specimens deposited in the lichen herbarium at the Korean Lichen Research Institute, and the samples were identified on the basis of recent literature. In this revisionary study, a total of eight species of Sticta, including a newly recorded one are documented. These species include Sticta fuliginosa (Dicks.) Ach., Sticta gracilis (Mull. Arg.) Zahlbr., Sticta limbata (Sm.) Ach., Sticta nylanderiana Zahlbr., Sticta sublimbata (J. Steiner) Swinscow & Krog, Sticta weigelii (Ach.) Vain., Sticta wrightii Tuck., and Sticta yatabeana Mull. Arg. Detailed descriptions of S. nylanderiana, S. sublimbata, S. weigelii, and S. yatabeana with their morphological, anatomical, and chemical characteristics are provided. A key description of all known Sticta species of the Korean Peninsula is also presented.

The Lichen Genus Polychidium New to South Korea

The lichen species Polychidium muscicola was found in South Korea for the first time and this is the first record of the genus Polychidium from the Korean peninsula. This species is characterized by a dichotomously branched minute thallus with clustered cells of Nostoc as the photobiont. A detailed description and illustrations of this species are provided.

[Treatment of industrial waste water from bacterial contamination by using ethanolic algae extract]

The effect of the ethanolic extract of two algae Nostoc linkia and Chara sp has been tested on the growth of bacteria Escherichia coli, Pseudomonas aeruginosa which was isolated from contaminated water under laboratory conditions of 37°C and treatment period of 72 hour for two algae. The extract of Nostoc linkia showed high efficiency in reducing the bacterial number at concentration 1 mg/I at removal rates 98.9% for Escherichia coli and 94.6% for Pseudomonas aeruginosa. Algaeal extract of Chara sp at concentration 1 mg/I caused a reduction in bacterial numbers at a removal rate of 87% for Escherichia coil and 87% for Pseudomonas aeruginosa with a significant differences at concentrations of 0.75 and 1 mg/I for two algael extract. Total bacterial number is reduced by concentration of 1 mg/I for two algael extract Nostoc linkia and Chara sp. at removal rates 90.8% and 82.4 respectively after 24 hour of treatment

Chromium (VI) tolerance in two halotolerant strains of Nostoc.

The present study reports on chromium (VI) tolerance of two cyanobacterial strains Nostoc linckia and Nostoc spongiaeforme isolated from salt affected soils using uni-algal and bi-algal systems. Besides distinct halophilism, the two strains exhibited remarkable tolerance to chromium (VI) and revealed 1.2 to 2.8 times more chlorophyll in the presence of the metal. While phycobilins and carotenoids also increased in Nostoc linckia with total dissolved salts (TDS) as well as metal, a decline was observed in Nostoc spongiaeforme in the presence of Cr (VI). Relative algal biomass (as % of control) showed significantly higher values (123-239) in Nostoc linckia in the presence of salt, metal and combination of the two. In Nostoc spongiaeforme it declined in the presence of metal (72-81) but increased in the presence of salts (143-249) and also in the binary systems (121-440). The bi-algal consortium showed relatively less tolerance to salt and metal stress. Nostoc linckia (20 day culture) showed upto 40% chromium removal whereas Nostoc spongiaeforme showed up to 12% removal, indicating greater suitability of the former for use in bioremediation studies.

Purification and characterization of extracellular polysaccharides from Nostoc flagelliforme / 生物工程学报

The extracellular polysaccharides (EPS) of N. flagelliforme were purified by DEAE anion exchange chromatography and Sephadex G100 gel filtration chromatography. And two main components named NFPS1 and NFPS2 were obtained respectively. The physico-chemical characteristics of NFPS2 were analyzed and compared with NFPS0, which was obtained from field colony of N. flagelliforme. These results showed that both of NFPS2 and NFPSO were composed of four monosaccharides: glucose, xylose, galactose and mannose. The apparent molecular weight of NFPS2 and NFPS0 was estimated to be 2.79 x 10(5), 2.26 x 10(5) respectively. They are non-sulfated polysaccharides, free of protein and nuclear acid. The thermal analysis indicated that there was a decomposition peak at 245 degrees C in thermogravimetric (TG) curves. However, the microstructure analysis showed that they had different porous structures.

Effect of UV-B and high visual radiation on photosynthesis in freshwater (nostoc spongiaeforme) and marine (Phormidium corium) cyanobacteria.

Human activity is causing depletion of ozone in stratosphere, resulting in increased UV-B radiation and global warming. However, impact of these climatic changes on the aquatic organism (especially marine) is not fully understood. Here, we have studied the effect of excess UV-B and visible radiation on photosynthetic pigments, fatty acids content, lipid peroxidation, nitrogen content, nitrogen reductase activity and membrane proteins, induction of mycosporine-like amino acids (MAAs) and antioxidant enzymes superoxide dismutase (SOD) and ascorbate peroxidase (APX) in freshwater (Nostoc spongiaeform) and marine (Phormidium corium) cyanobacteria. UV-B treatment resulted in an increase in photosynthetic pigments in Nostoc and decrease in Phormidium, but high light treatment caused photobleaching of most of the pigments in both the species. Unsaturation level of fatty acids of both total and glycolipids remained unchanged in both the cyanobacteria, as a result of UV-B and high light treatments. Saturated fatty acids of total and glycolipids declined slightly in Nostoc by both the treatments. but remained unchanged in Phormidium. No changes in the unsaturated lipid content in our study probably suggested adaptation of the organism to the treatments. However, both treatments resulted in peroxidation of membrane lipids, indicating oxidative damage to lipids without any change in the level of unsaturation of fatty acid in the cell membrane. Qualitative and quantitative changes were observed in membrane protein profile due to the treatments. Cyanobacteria were able to synthesize MAAs in response to the UV-B treatment. Both treatments also increased the activities of SOD and APX. In conclusion, the study demonstrated induction of antioxidants such as SOD and APX under visible light treatment and screening pigment (MAAs) under UV-B treatment, which might protect the cyanobacteria from oxidative damage caused by high light and UV-B radiation.

Produção de exopolissacarídeos pela cianobactéria Nostoc sp em diferentesconcentrações de nitrogênio e glicose / Exopolysaccharide production by the cyanobacteria Nostoc sp in

Cianobactérias são microrganismos procariontes que, durante o crescimento celular, são capazes de produzir exopolissacarídeos (EPS). Devido à diversidade bioquímica destes, podem ser excelentes para vários fins biotecnológicos, tendo aplicações em indústrias alimentícias, têxteis, de tintas, cosméticos, de papel, e farmacêuticas, como floculantes, espessantes ou estabilizadores, substituindo os polissacarídeos de macroalgas e plantas. Além disso, as cianobactérias apresentam taxas maiores de crescimento e são mais fáceis de manipular do que plantas e macroalgas. Este estudo teve por objetivo otimizar a produção de EPS no meio BG11, com relação a diferentes concentrações de nitrogênio e glicose do meio de cultivo na produção de EPS e biomassa pela cianobactéria Nostoc sp.

Screening of Cyanobacteria (Blue-Green algae) from Rice Paddy Soil for Antifungal Activity against Plant Pathogenic Fungi

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.

A Small Cryptic Plasmid pZMO1 of Zymomonas mobilis ATCC10988

The nucleotide sequence of pZMO1, a small cryptic plasmid of Zymomonas mobilis ATCC10988 was determined. Analysis of 1,680 bp of sequence revealed 69% identity with Shigella sonnei plasmid, pKYM and 61% identity with Nostoc sp. ss DNA replicating plasmid. Analysis of a deduced amino acid sequence of an orf of pZMO1 revealed 75% identity and 90% similarity with the repA gene of Synechocystis sp. plasmid pCA2.4. The upstream region of the repA gene of pZMO1 possesses six directed repeat sequences and two inverted repeat sequences at downstream of the IR consensus sequence of nick region of rolling circle replication (RCR) plasmid. A typical terminator hairpin structure was found at the downstream region of repA gene. Degradation of single-stranded plasmid DNA by S1 nuclease was detected by Southern hybridization. It suggests that pZMO1 replicates by a rolling circle mechanism in Z. mobilis ATCC10988 cells.