Phormidium Tenue Research Articles

Co-inoculation of fungi and desert cyanobacteria facilitates biological soil crust formation and soil fertility.

The inoculation of cyanobacteria for enriching soil nutrients and forming biological soil crusts (BSCs) is considered an effective means to restore degraded soil. However, there are limited studies on the application of co-inoculation of fungi and cyanobacteria for degraded soil remediation. In this study, a high exopolysaccharide-secreting fungi Zh2 was isolated from lichen BSCs in Hobq Desert, and co-inoculated with a cyanobacterial strain identified as Phormidium tenue in different proportions to form BSCs on sand during a 35 days incubation period. Results revealed significant differences in crust biomass and soil properties among crusts with different cyanobacterial/fungal inoculation ratios. Microbial biomass, soil nutrient content and enzyme activities in crusts co-inoculated with cyanobacteria and fungi were higher than those inoculated with cyanobacteria and fungi alone. The inoculation of cyanobacteria contributed to the fulvic-like accumulation, and the inoculated fungi significantly increased the humic-like content and soil humification. Redundancy analysis showed that the inoculation of cyanobacteria was positively correlated with the activities of urease and phosphatase, and the content of fulvic-like. Meanwhile, the inoculation of fungi was positively correlated with the contents of total carbon, total nitrogen and humic-like, the activities of catalase and sucrase. Cyanobacteria and fungi play distinct roles in improving soil fertility and accumulating dissolved organic matter. This study provides new insights into the effects of cyanobacteria and fungi inoculations on the formation and development of cyanobacterial-fungus complex crusts, offering a novel method for accelerating induced crust formation on the surface of sand.

Enhancement of nitrogencycling 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 0.864g/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.

Comparative physiological response of filamentous cyanobacteria Phormidium tenue and Leptolyngbya lignicola under chromium (VI) stress

AbstractNumerous technologies for cleaning the environment without producing hazardous waste products have arisen in response to the rise in environmental pollution. Industrialization and the growing population have put society to a hard test. Continuous discharge of heavy metals (chromium, nickel, copper, mercury etc.) in water bodies is increasing by anthropogenic activities; these cause bio accumulation and shift towards a resistant microbial community. These hazardous metals enter the human body through water and food, creating a slew of health issues. Chromium (VI) is one such toxic pollutant and is more toxic than chromium (III). Several environment‐friendly technologies have been developed for decontaminating wastewater by using microorganisms. Microalgae, cyanobacteria, bacteria and fungi are used for heavy metals eradication from the water due to their metal tolerance, bioaccumulation and biotransformation capacity. In this study two cyanobacteria strains were compared for their physiological response and metal tolerance for Cr (VI) stress. Leptolyngbya lignicola and Phormidium tenue were grown in a medium containing various concentrations of chromium (1 ppm, 2 ppm, 3 ppm, 4 ppm, 5 ppm, and 10 ppm), and biochemical parameters (chlorophyll, carotenoids, protein, proline, amino acid, carbohydrate, reducing sugar and lipid content) were measured. The findings revealed that P. tenue was more sensitive to metal stress than L. lignicola. P. tenue showed a decreasing trend for all biochemical parameters except proline at higher ad lower doses of Cr (VI) stress. However L. lignicola showed an increase in biomass (6.09%) and other biochemical parameters over control at lower metal stress concentration (1 ppm), whereas, a gradual decrease in all parameters except proline was observed at higher concentrations. Further L. lignicola showing high tolerance index can be preferred for metal remediation from the water bodies of heavy metal contaminated area.

Comparison of the microalgae Phormidium tenue and Chlorella vulgaris as biosorbents of Cd and Zn from aqueous environments

Heavy metals are accumulating into sediments and enriching in aquatic food chains. The efficiency of two microalgae, Phormidium tenue and Chlorella vulgaris, to remove zinc and cadmium from aqueous solutions was studied. The microalgae were incubated in different heavy metal concentrations for 18 days. Morphological and anatomical changes in microalgae were investigated using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Both algae removed both Zn2+ and Cd2+in vitro. C. vulgaris removed Zn2+ almost totally (99%) and Cd2+ slightly less (87%). The concentration factors were 2210 and 1117, respectively. SEM and TEM figures showed some alterations in the form and cellular components of both algae. C. vulgaris appeared to be more tolerant to both Cd and Zn than P. tenue. C. vulgaris is a promising microalgal species used to remove heavy metals from aqueous environments.

Antihyperlipidemic Activity of Phormidium Tenue on High Cholesterol Diet Induced Hyperlipidemia in Wistar Albino Rats

This study investigated antihyperlipidemic activity of Phormidium tenue on high cholesterol diet induced hyperlipidemia in Wistar albino rats. The ethanolic extract of P. tenue was given at the dose of 1 g/kg to the group of animals once in a day along with the high cholesterol diet orally, for 25 days. There was a significant increase in body weight of high cholesterol diet rats, compared to normal rats. However, there was no change in the body weight of test groups treated with P. tenue. The treatment also significantly reduced the levels of serum cholesterol, Triglyceride (TG), Low Density Lipoprotein (LDL) and Very Low-Density Lipoprotein (VLDL) and increased the level of High-Density Lipoprotein (HDL) in hyperlipidemic rats nearer to standard drug. Histopathological studies revealed that the coronary artery wall appeared normal, with no foam cells, no disturbance in the endothelial cell and no change in the muscle fibers in the control group or standard drug treated group. The coronary artery wall of the algal treated rats was similar to that of the normal rats. Our study suggests that P. tenue has the potential protective role for coronary heart disease, and hence further clinical trials are required to explore natural biomolecules towards developing drug.

Relationship between phytoplankton distribution and salinity in the giant artificial brackish Lake Saemangeum

In 2021, an abundance of phytoplankton species was observed in Lake Saemangeum. We analyzed the relationship between phytoplankton abundance and salinity by comparing the distribution of salinity that changed because of freshwater inflow and drainage sluice gate operation. Thirteen field surveys were conducted: monthly basic surveys from January to November 2021 and additional surveys after rainfall in August and September at seven sites. During the survey period, 46–94 species were recorded. Pearson correlation coefficients were used to analyze the relationship between salinity and abundance of the dominant phytoplankton species. The result showed that Cyclotella atomus, Stephanodiscus hantzschii, Phormidium tenue, and Chaetoceros spp. were correlated with salinity. Chaetoceros spp. was significantly positively correlated (p < 0.001), whereas all other species were negatively correlated. Moreover, the correlation coefficient between seven species and salinity was close to zero. Compared with the general correlation coefficient of salinity and abundance, the point-biserial correlation coefficient showed a higher overall absolute value. Four species (Skeletonema spp., Cyclotella atomus, Phormidium tenue, Chaetoceros spp.) exhibited p < 0.001. Particularly, the correlation coefficient of Cyclotella atomus changed significantly from -0.237 to -0.451, whereas that of Phormidium tenue changed from -0.207 to -0.431. The results imply that salinity can affect the distribution and survival of euryhaline species. Therefore, high salinity may inhibit some freshwater and euryhaline species in the lake. However, further research is required to validate our findings.

How Can We Stabilize Soil Using Microbial Communities and Mitigate Desertification?

The desert, which covers around one-third of Earth’s continental surface, is defined as the harshest terrestrial environment and comprises a highly extensive biome of the terrestrial ecosystem. Microorganisms are key drivers that maintain the integrity of desert terrestrial ecosystems. Over the past few decades, desertification has increased owing to changes in rainfall patterns and global warming, characterized by land degradation, loss of microbial diversity (biocrust diversity), and multifunctionality with time. Soil stabilization is a geotechnical modality that improves the physiochemical properties of the soil. Biological modality is an emerging method that attracts the scientific community for soil stabilization. Enriching the soil with microorganisms such as some bacteria geniuses (Cystobacter, Archangium, Polyangium, Myxococcus, Stigmatella and Sorangium, Bacillus, Acinetobacter, Proteus, Micrococcus, and Pseudom) or Cyanobacteria (Oscillatoria pseudogeminata, Chroococcus minutus, Phormidium Tenue, and Nostoc species), and Lichens (Collema sps., Stellarangia sps., and Buellia species) might contribute to stabilizing the soil and mitigating desertification. In this timeline review article, we summarize the biological method of soil stabilization, especially focusing on the role of microorganisms in soil stabilization in the desert.

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 (30min), starting concentration (50mgL-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 (60min). 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.

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.

Using Mouteh goldmine soil cyanobacteria for tailing damp soil bioremediation

Introduction: Natural and human activities lead to soil degradation and soil salinization. In the last two centuries, world metal pollution level has increased extremely. Presence of some heavy metals in aquatic ecosystems is a constant threat to the health of human societies. The decrease of farmlands threatens food security. There are approximately 1 billion ha salt-affected soils all over of world, which can be made available resources after chemical, physical and biological remediation. Existence of many mines in the world and also in Iran and as a result, soil erosion and dust release from waste dams is matter of concern. Bioremediation using biological agents to detoxify and degradation of environmental pollutants- provides a suitable alternative method for substitution of current heavy metals removal strategies. Material and methods: Daily as a result of extraction operations by cyanidation in Mouteh gold mining complex, waste water and waste soil sediment widely achieved. In this study soil samples were collected from Mouteh Goldmine tailing damp soil in September 2018. The collected soil samples were cultured in BG11 medium and incubated for microalgae identification and biomass production. Also 5 gr soil inoculated with 0.5 gr biomass and the physico-chemical characteristics of the soil including pH, Na+ and K+, Pb and Cd, before and after the inoculation of soil with Cyanobacteria were determined.Results and discussion: in this study, cyanobacteria Phormidium tenue Gomont, Osillatoria tenuis C.Agardh ex Gomont, Lyngbya aestuarii Liebman ex Gomont and green Algae, Scenedesmus obliquus (Turpin) Kutzing were identified. Culture results of filamentous cyanobacteria on goldmine tailing damp soil showed that cyanobacteria can grow easily and produced a surface crust significantly. The results of the Physical analysis of the soil samples showed that O. tenuis decreased Na as a salinity element, and P. tenue absorbed high amounts of Pb as a heavy metal pollution element. Probably by using Mouteh Goldmine soil cyanobacteria, Osillatoria tenuis and Phormidium tenue for mine tailingdamp soil bioremediation, could play mine recovery from salinity and heavy metals and also preventing soil erosion and dust release from waste dams.Conclusion: Generally, it can be concluded thatdue to the existence of many goldmines in the word and Iran, daily as a result of extraction operations by cyanidation and high toxicity of cyanide, environmental adverse effects are observed. Dust release from waste dams can be affected health of living organisms like mining workers, plants and even soil microalgae which are close to the mine. By soil goldmine bioremediation can be processed biological resuscitation faster. The research results of African goldmine researchers on soil samples showed that cyanobacteria produced a surface crust significantly, that with the results of this research based on the growth of Phormidium tenue in the mine and producing a surface crust is consistent.

Structural Characteristics of Zooplankton and Phytoplankton Communities and Its Relationship with Environmental Factors in a Typical Tributary Reservoir in the Three Gorges Reservoir Region

Based on the data of zooplankton, phytoplankton, and water environmental factors in different seasons in a typical tributary reservoir in the Three Gorges Reservoir Region (Changshou Lake), this study explored the relationships between the structures of the zooplankton and phytoplankton communities and environmental factors using Pearson correlation analysis. The results showed that there were a total of 107 species of 8 phyla of phytoplankton, and cyanobacteria was the most critical constituent with a relative abundance of 61%. The dominant populations included Phormidium tenue, Merismopedia punctata, and Anabaena oscillarioides. A total of 82 species of 4 phyla of zooplankton were identified, and rotifers was the most abundant with a relative abundance of 88%. The dominant populations included six species, such as Keratella cochlearis, Asplanchna priodonta, and Asplanchna girodi. The spatial differences in the abundances, biomass, and biodiversity indexes of zooplankton and phytoplankton were not significant, whereas the seasonal differences in all the other indexes were significant, except for the zooplankton biodiversity indexes. The abundance of phytoplankton was the highest in summer, followed by spring, and it was the lowest in winter. The maximum abundance of zooplankton occurred in spring, and the biomass of zooplankton and phytoplankton in spring was significantly higher than that in winter. The number of phytoplankton species and the Shannon-Wiener index, Pielou's uniformity index, and Margalef richness index in summer were significantly lower than those in winter and spring. The water quality evaluation showed that Changshou Lake was in a clean to oligo-pollution state in winter and spring and a moderate-pollution state in summer, thereby suggesting that Changshou Lake was in an overall eutrophic state. The environmental factors, including Chla, DOC, nutrients (TP, NO2--N, NO3--N, and NH4+-N), DO, Eh, and T, influenced the structures of the zooplankton and phytoplankton communities in Changshou Lake, and there were seasonal differences in the environmental factors.

Gold Bioaccumulation by Filamentous Soil Cyanobacteria isolated from Mouteh Goldmine (Isfahan Province, Iran)

This study was aimed to investigate the possible exploitation of phototrophic microorganisms for the oxidation of Au3+ containing composites as well as recovery and bioaccumulation of Au3+ from Mouteh goldmine soil samples. Mechanisms of accumulation including oxidation, dissolution, reduction, leaching and sorption were investigated. After 3 weeks of cyanobacterial growth, gold bioaccumulation from Mouteh gold mine soil solution were determined. Then biomass digested with acidic solutions and subsequently gold amounts were analyzed with Atomic Absorption Spectroscopy. Soil sample with 2 ppm Au3+containing composites ore from Mouteh goldmine were collected. At the end of experiments, the concentration of gold in biomass was almost 6.5 ppm. Results indicated that two soil cyanobacteria species from Mouteh goldmine could bind gold in gold bio-mining process. Bioaccumulation percent was 32% and 30% for Phormidium tenue Gomont and Osillatoria tenuis C. Agardh ex Gomont respectively. Cyanobacterial gold accumulation were determined 6.5 gr/kg biomass dried weight.

Environmental and cultured cyanobacteria as sources of Aedes aegypti larvicides

In tropical countries, the control of the mosquito Aedes aegypti is a public health priority due to its role as a vector of important viral diseases. Marine cyanobacteria are recognized as abundant sources of bioactive compounds, and they constitute a potential source of insecticides useful for controlling mosquito populations and preventing epidemic outbreaks. We collected 30 benthic cyanobacterial mats in Providencia and Rosario islands (in the Colombian Caribbean) belonging to the genera Phormidium, Symploca, Oscillatoria, Lyngbya, Pseudoanabaena, Leptolyngbya, Moorea, and Dapis. Fractions of organic extracts from the most abundant environmental samples were evaluated in three bioassays, assessing (i) larvicidal activity against A. aegypti, (ii) toxicity against the brine shrimp (Artemia salina) nauplii, and (iii) acetylcholinesterase inhibition. Non-polar fractions exhibited larvicidal activity. The polar fraction from one Dapis pleuosa extract showed larvicidal activity without being toxic against A. salina nauplii. Extracts from Moorea producens exhibited the greatest toxicity against A. aegypti larvae and A. salina nauplii. From 23 cultured cyanobacterial samples, only five grew under laboratory conditions and produced enough biomass to yield organic extracts. Of these, three extracts showed strong larvicidal activity, but only the extract from Phormidium tenue showed reduced toxicity against A. salina nauplii. We detected variation among the chemical profiles and larvicidal activity of cyanobacterial consortia depending on sites and dates of collection. Our findings suggest that despite variation in chemical profiles, extracts of marine benthic cyanobacteria can be further developed as effective control agents against insect vectors, in their larval stages. The culture of marine benthic cyanobacteria needs to be further explored to provide enough biomass leading to the identification of bioactive compounds with public health applications.

Changes in the phytoplankton community structure of the Backshore Wetland of Expo Garden, Shanghai from 2009 to 2010

Phytoplankton community structure, abundance, and species' spatial and temporal distributions were examined for the Backshore Wetland of Expo Garden in Shanghai from September 2009 to August 2010. A total of 371 phytoplankton species were identified from 109 genera 8 phyla. There were 18 dominant species in total, and Phormidium tenue was dominant during four seasons. The mean annual abundance and biomass were 711.11 × 104 cells/L and 5.70 mg/L, respectively. The seasonal changing trend of existing stocks was bimodal, with main peaks of density and biomass occurring in the winter and a secondary peaks occurring in the summer. The Shannon–Wiener diversity index (H′), the Margalef species richness index (D), and Pielou's species evenness index (J) showed a clear seasonal trend. All of the indices showed a changing pattern, with the highest recorded values from the summer to autumn and the lowest recorded values from the winter to spring. The canonical correspondence analysis (CCA) showed that environmental factors, including water temperature, nitrate nitrogen, and pH were the main influencing factors to the change of phytoplankton community structure in the Backshore Wetland of Expo Garden in Shanghai.

Variations in cyanobacterial and algal communities and soil characteristics under biocrust development under similar environmental conditions

Cyanobacterial and algal communities have a large effect on biocrust formation and development. Biocrust species and abundance vary spatially and temporally due to different environmental factors. The relationships among cyanobacterial and algal communities, and biocrust function have been studied extensively. Lacking, however, are studies of temporal changes in a similar landscape where environmental conditions are similar, but where biocrust formation is different. Biocrusts of different ages were located in the Loess Plateau in an area that had experienced a landslide. We examined changes in cyanobacterial and algal communities, carbon, nutrients, and the composition of dissolved organic matter in the topsoil, and the relationships among the community and soil characteristics using redundancy analysis. Phormidium tenue (Cyanophyta) dominated in all biocrusts, and co-dominated in a newly formed crust with Euglena sp. (Euglenophyta). Oscillatoria sp. (Cyanophyta) increased with biocrust age. Oscillatoria was positively correlated with carbon fixation and nutrient (nitrogen and phosphorus) accumulation in topsoils. While incubation of Phormidium tenue and Euglena sp. is suggested for rapid biocrust formation at an early stage, increasing the abundance of Phormidium tenue and Oscillatoria sp. can promote carbon fixation and nutrient (nitrogen and phosphorus) accumulation, thereby accelerating biocrusts into a later stage.

ANTIBACTERIAL ACTIVITIES OF SOME ISOLATED ALGAE FROM SIWA OASIS-EGYPT

In compliance to the recent surveys on algal species and their potentials to produce biologically active natural products, collection of algae were carried out during summer 2014 from five water habitats in Siwa Oasis. Three common microalgal pure isolates including one green alga Chlorella vulgaris and twoblue green algae Chroococcus turgidus and Phormidium tenue were obtained using BG11, Basal Bold and Zarrouk media. The methanolic extracts of the three algal species were tested for the antibacterial activity against eight human pathogenic bacteria Enterococcus sp., Staphylococcus aureus, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumonia, Proteus sp., Pseudomonas aeruginosa and Salmonella tyhphi using the agar well diffusion method. The results revealed that Phormidium tenue showed the highest promising antibacterial activity so it was choosed for successive extraction by using petroleum ether, ethylacetate, 80%methanol and water solvents. Among the tested solvents the ethyl acetate successive extract showed the highest antibacterial activity. Results of some chromatographic investigations for the ethyl acetate extract indicated that the phenolic compounds were the main components. High performance liquid chromatography (HPLC) technique was used for qualitative and quantitative analysis of the bioactive phenolic compounds. It resulted in identification of 22 phenolic compounds with different concentrations ranging from 1755.2 to10.425 μgg-1for ethyl vanillate and catechol compounds, respectively.

Cell damage caused by ultraviolet B radiation in the desert cyanobacterium Phormidium tenue and its recovery process

Phormidium tenue, a cyanobacterium that grows in the topsoil of biological soil crusts (BSCs), has the highest recovery rate among desert crust cyanobacteria after exposure to ultraviolet B (UV-B) radiation. However, the mechanism underlying its recovery process is unclear. To address this issue, we measured chlorophyll a fluorescence, generation of reactive oxygen species (ROS), lipid peroxidation, and repair of DNA breakage in P. tenue following exposure to UV-B. We found that UV-B radiation at all doses tested reduced photosynthesis and induced cell damage in P. tenue. However, P. tenue responded to UV-B radiation by rapidly reducing photosynthetic activity, which protects the cell by leaking less ROS. Antioxidant enzymes, DNA damage repair systems, and UV absorbing pigments were then induced to mitigate the damage caused by UV-B radiation. The addition of exogenous antioxidant chemicals ascorbate and N-acetylcysteine also mitigated the harmful effects caused by UV-B radiation and enhanced the recovery process. These chemicals could aid in the resistance of P. tenue to the exposure of intense UV-B radiation in desertified areas when inoculated onto the sand surface to form artificial algal crusts.

Marine Organisms as Biomedical Resources Enrich Quality of Life

The Ocean, called the ‘mother of origin of life’, is a rich source of biological and chemical diversity. Marine floras include microflora (bacteria, actinobacteria, cyanobacteria and fungi), microalgae, macroalgae (seaweeds), and flowering plants (mangroves and other halophytes). Marine organisms have unique properties as they are exposed to extreme marine environmental conditions. This vast marine floral resource offer a great way for discovery of new drugs which can fight deadly diseases like cancer, acquired immune deficiency syndrome (AIDS), arthritis, etc. Sea has got plenty of metabolites and other resources in living or dead form. Thermo-stable proteases, lipases, esterases, and starch and xylan degrading enzymes have been actively sought from bacterial and archaeal hyperthermophilic marine microorganisms. Marine cyanobacteria appear to be potential sources for production of vitamins such as B complex group and vitamin-E. The carotenoids and phycobiliprotein pigments of cyanobacteria have commercial value as natural food colouring agents, as feed additives, as enhancers of the color of egg yolks, to improve the health and fertility of cattle, as drugs and in the cosmetic industries. Some anti-HIV activity has been observed with the compounds extracted from Lyngbya lagerhaimanii and Phormidium tenue. Thus an attempt to review few marine derived biomedical resources was done emphasizing that with the advent of modern technologies it is anticipated that the marine environment will become an invaluable source of novel compounds in the future.

팔당호 퇴적층 남조류의 군집과 남조류 성장잠재성 분석

We analyzed cyanobacterial community including akinete, resting cell, and benthic cyanobacteria in sediment of Bukhan, Namhan-River, Paldang-Lake, and Kyeongan-Stream and compared the physicochemical factors for water and pore water. We also performed cyanobacteria growth potential test through incubating sediment. As a result of physicochemical analysis, the concentrations of nutrients were similar for each depth of Bukhan-River. For Namhan-River and Lake Paldang sites, the concentrations of TP and DTN in bottom and deep water had higher levels. DTN in water body composed of NO3-N(73%) while DTN in pore water composed of NH3-N(77.8%). Benthic cyanobacteria in the sediment such as Oscillatoria tenuis, O. limosa, Phormidium tenue, Pseudanabaena limnetica, and Lyngbya sp. were dominant (between 0.0∼243.3×10³ cells/g, w/w). Cell densities of cyanobacteria in sediment depth of 0∼2 cm in most sites were higher compared to those in other depths. The cell density of cyanobacteria in sediment correlated with pH, conductivity, BOD5, TP, DTP, and chl. a. Increased phytoplankton and organic matters were found to be able to inhibit the growth of benthic cyanobacteria. Results of cyanobacteria growth potential test after incubating sediment revealed that harmful cyanobacteria (Anabaena, Aphanizomenon, Microcystis, and Oscillatoria) appeared at 7 days post culturing. Base on these results, the methods used in this study are considered to be able to determine the appearance of harmful cyanobacteria.

Pseudanabaena foetida sp. nov. and P. subfoetida sp. nov. (Cyanophyta/ Cyanobacteria) producing 2-methylisoborneol from Japan

Nasty smell of tap water supplied from Lake Biwa caused a great trouble. Then many researches have been conducted from the point of view of water supply management or water quality in Japan. The matter of this bad smell was identified as 2-methylisoborneol (2-MIB) and the source organism of this bad odor was then reported as Phormidium tenue and later two different cultured strains were established. One of these strains shows green color, produce 2-MIB, and is marked PTG. The other shows brown color, does not produce 2-MIB and is marked PTB. However their nomenclatural description has not been done yet and, in fact, they have morphological characters of genus Pseudanabaena rather than Phormidium. Pseudanabaena species are also observed in Lake Kasumigaura. PS1306 produces 2-MIB and other strain PS1303 has no smell. This study focuses on morphological and genetical (16S rRNA) comparison of strains from both lakes. In addition, the ultrastructure of cells of PTB and PTG are demonstrated. On the basis of this comparison we propose description of two new planktic species producing 2-MIB: Pseudanabaena foetida Niiyama, Tuji et Ichise sp. nov. and P. subfoetida Niiyama et Tuji sp. nov.