Environmental Sciences
Year:2012 | Volume:9 | Issue:SPECIAL ISSUE|Papers Count:11

In the present study, the efficiency of Ampicillin, Kanamycin, Vancomycin and Rifampicin concentrations (0.05, 0.1 and 0.3 mg.l-1) in the elimination of bacterial contamination in unicellular algae Dunaliella sp. cultures was evaluated. Each antibiotic was able only to reduce the contaminant bacterial population in cultures. However, the combination of two antibiotics (from Ampicillin, Kanamycin and Vancomycin) in 0.05 mg.l-1 and 0.1 mg.l-1 concentrations resulted in the elimination of bacterial contamination by the Ampicillin-Kanamycin mixture at 0.1 and 0.05 mg.l-1, respectively. Algae population change study using OD680 determination and cell counting showed that, except for Rifampicin, the other antibiotics did not reduce algal growth. Moreover, the Dunaliella sp. population was higher in the presence of Ampicillin compared with the control.

The S-layer is the surface cell wall layer in cyanobacteria. S-layers have a 5–10 nm thickness and identical, regularly arranged pores with diameters of 2–8 nm. The self-assembly process can occur in the air-water interface. Drug targeting is the selective delivery of drugs to particular tissues and cells and it can increase the efficiency of medical treatment, reduce the required dose and decrease the side effects of a drug. The mechanisms of attaching drugs to drug targeting materials vary according to the physicochemical properties of these materials. In this study, the S-layer of Spirulina ISC6 cyanobacteria was used to deliver the anti-blood cancer drug L-Asparaginase to cancer cell lines. In this study the use of nano particles of the Spirulina ISC6 S-layer for the delivery of L-Asparaginase to cancer cell lines was investigated. Spirulina ISC6 was cultured in zarrouk media and the S-layer was extracted from the outer membrane of cyanobacteria using the standard method. Quantification and qualification of the extracted S-layer was done and it was sterilized by filtration. Different concentrations of S-layer and L-Asparaginase were tested on cancer cells. The cell mortality was compared with that of untreated cells, S-layer alone and L-Asparaginase treated cells alone. Results showed that cancer cells treated with S-layer and L-Asparaginase decreased better than cancer cells treated with other compounds.

Due to the presence of algae in the air and groundwater, larger areas are allocated for them in comparison with other flora. According to studies, the biodiversity of algae in Iran is estimated at 7000 species. Given the abundant and diverse habitats around the country, inclusion of their diversity and distribution is inevitable. For this purpose, a broad research tool was designed using software in order to: 1) create an interactive list for classification of algae from division to the lowest taxon; 2) count and display each of the records based on algae identity; 3) search synonyms; 4) allow for various options such as algae habitat types, fossilogy, environmental aspects and so on; 5) chart the specific index distribution of records based on 31 provinces with scientific references; 6) map the distribution of the records with the exact and/or approximate locations; 7) provide images of retrieved algae with the ability to zoom; 8) data analysis and evaluation of their reported positions in limits and orientation; 9) numerical computation of diversity for any taxa; and 10) creating technical reports. In this algorithm, the possibility is allowed for other data layers such as natural geography. Therefore, due to the value of such transnational research, the development and completion of this tool is essential.

The members of the Characeae family are also known as stonewort and usually inhabit submerged conditions in slow running and standing water. They have long axes and whorls of leaf-like structures at the nodes. Systematic sampling was undertaken during July to September of 2008 with collection in Markazi Province (Iran). Eighteen populations were collected for five species from 16 sites. Morphometric studies were performed on populations of four Chara species of the section Chara: Chara vulgaris L., C. gymnophylla A. Br., C. Contraria A. Br. ex Kutz. and C. kirghisorum Less. And, in addition, Nitella hyalina (D.C.); C.A. Agardh belongs to the section Decandollea in the genus Nitella as an outgroup. This was done with the aim of finding inter-specific relationships and the clustering showed the distinctness of the species. Principal Coordinate analysis identified the same species in the separate groups. Morphological characteristics were also identified.

Naphthalene is one of the toxic oil compounds which have hazardous effects on the environment. In this research the physiological effects of this compound on cyanobacteria was evaluated, namely on oil biodegredative autotrophs. For this purpose cyanobacterium Leptolyngbya sp. ISC 25 was collected and isolated from regions polluted by oil. After liquid cultivation using carbonless BG11 medium, this cyanobacterium was treated with (0, 0.025, 0.05, 0.2, 0.4, 0.6, 0.8 and 1%) of naphthalene. Physiological responses like survival, Chla, photosynthesis and ammonium excretion were investigated in a logarithmic phase of the growth curve. Survival was evaluated spectrometically at 750 nm and photosynthesis via Oxyview instrument. Results indicated that Chla concentration decreased as naphthalene increased and the reduction slope was higher in 0.6, 0.8 and 1%. In 0.8 and 1% naphthalene, Chla concentration was approximately zero. phycobiliprotein content was enhanced up until 0.2% of naphthalene, but in 0.4, 0.6, and 1% naphthalene decreased significantly. Comparison of survival rates on different days showed that biomass was initially enhanced in all treatments, but decreased at 0.4, 0.6, 0.8 and 1% naphthalene. In other treatments this increasing feature remained although the rate was slower. The rate of hotosynthesis and ammonium excretion decreased in all treatments. In total, this cyanobacterium can tolerate 0.025, 0.05 and 0.2% of naphthalene and the 0.6 and 1% of naphthalene is toxic for it.

This study was conducted to assess the trophic status based on the scaled trophic state index (TRIXCS) and unscaled trophic index (UNTRIX) in the southern Caspian Sea. The results showed that TRIXCS and UNTRIX values fall within a range from about 4.69 to 5.58 (Meso-eutrophic) and 3.58 to 4.16 (no and high eutrophication risk) at different seasons, respectively. As a conclusion, the trophic index for the Caspian Sea (TRIXCS) which was evaluated for long-term trends was suitable and potential for classification of the trophic status of the Caspian Sea. The UNTRIX and TQRTRIX-based trophic classification is in good agreement with TRIXCS for both summer and winter, however, there is no agreement regarding annual classification. Therefore, this alternative method will be able to be applied for short-term trends, taking into account ecological events and other indices in the southern Caspian Sea.

The epipelic, epilithic and epiphytic algae of Miankaleh wetland were studied from June 2007 to June 2008. This was the first floristic study of algae in this wetland in northern Iran. Sixty three taxa (25 belonging to Chlorophyta, 24 to Bacillariophyta, 12 to Cyanobacterai, 1 to Xantophyta and 1 to Euglenophyta) were determined. All taxa are new records for the Miankaleh wetland and Mazandaran Province and 12 species represent new records for the algal flora of Iran. There was some similarity between the algal flora of the study area to that of other freshwater ecosystems in the North of Iran. Based on an analysis of the composition of the algal flora, Miankaleh wetland was typified as having an oligotrophic character. Bacillariophyta was the predominant group in the epipelic, epiphytic and epilithic communities of the Miankaleh wetland.

In this current research, two strains of Nostocaceae (Anabaena sp.FS76 and Nostoc sp. FS77) were collected from paddy fields in Golestan Province and were studied morphologically and ultra-structurally using optical, phase contrast, fluorescence and TEM electron microscopy. Results showed that, in comparison between strains, Anabaena sp.FS76 showed considerable fluctuations in the dimensions and shapes of cells on the third day, and it seems that the spatial form of this specimen changes on this day. Compression of the aggregations in liquid culture medium decreased sharply on the 8th day and remained in a similar form until the end of the period. The specimen exhibited interesting color changes from light brown to green-brown. Generally, the length of vegetative cells and spores is greater than their diameter. The vegetative cells in Anabaena sp.FS76 showed interesting shape and size variations, with vegetative cell length greater than diameter from the first to the 10th day but, on the 10th day to the end of the period, this turned to the opposite and stayed permanently this way. It seems that shapes of the thylakoides in ultra-structure analysis was not so changeable during the days in question and kept their relatively dense to linear configuration. In Nostoc sp.FS77, carboxysome and phosphate granules showed more varied shapes in comparison with Anabaena sp. FS76.

In order to investigate the taxonomic composition and physical and chemical characteristics of a thermal spring in Kilesephyd, the ecological factors of the headwater of a warm spring in Kilesephyd, Sar-e-Pol-e-Zohab in Kermanshah Province in Iran was carried out. Chemical and Physical Factors (So4-2, No3-, Cl-, Po4-2, Sio2-2, Mg+2, Ca+2, K+, pH, conductivity, turbidity) were measured against biological properties (Species composition, chlorophyll-a, Dry mass, Autotrophic index or AI and Ash free dry mass or AFDM). The headwater temperature of the thermal spring remained almost constant over years and the temperature is lower than the ambient temperature during the summer season (28oC). A high concentration of sulfate and conductivity is a characteristic feature of this spring. Water samples and cobbles or pebbles were collected from the headwater. At the end of the sampling study, 6 species of Cyanobacteria belong to four genera have been determined. Phormidium formosum and Oscillatoria sp. were abundant.

The production of antimicrobial compounds by cyanobacterial strains isolated from oil-polluted and non-polluted areas in Khozestan (Iran) was investigated, comparatively. For this purpose, the antimicrobial activities of supernatant and methanolic extracts from liquid cultures of strains of Phormidium tenue ISC24, Leptolyngbya sp. ISC25, Nostoc sp. ISC26, Phormidium sp. ISC27, Nostoc entophytum ISC32, Chroococcus pallidus ISC39 and Nostoc sp. ISC62 from oil-polluted samples, and strains of Fischerella ambigua ISC4, Calothrix sp. ISC11, Microcheate tenera ISC13, Nostoc sp. ISC17, Chroococcus minutus ISC35, Leptolyngbya sp.ISC38 and Spirulina sp. ISC6 from non-polluted samples, were measured against different gram-negative and gram-positive bacteria and fungal strains using a disc diffusion method. Except for fungal strains of Saccharomyces Cerviciae and Candida albicans, the isolates from non-polluted areas had a higher frequency of antimicrobial activity. In this group, the maximum frequency of effects was observed on B. subtilis with 9 cases, and the minimum frequency was observed on S. cervisiae with only one case. Also in the isolates from non-polluted areas, considerable antibacterial effects were observed on gram-negative bacteria. The strongest antimicrobial activity from the isolates collected from non-polluted areas belonged to the supernatant extracts of Spirulina sp. ISC6 on Bacillus sabtilis, with a 26 millimeter inhibition zone. B. subtilis and S. cervisiae, each with 6 positive effects, showed the maximum frequency of susceptibility to the extracts from the isolates from oil-polluted areas. In this group, the strongest effects were observed from the supernatant extracts of Chroococcus pallidus ISC39 and Phormidium tenues ISC24 on S. cervisiae with inhibition zones of 22 and 20 millimeters diameter, respectively. The antibacterial effects against gram-negative bacteria were not significant in these isolates. In general, a significant distinction in the antimicrobial activity between oil-polluted and non-polluted isolates was observed in the frequency of effects and also in the types of susceptible bacterial or fungal strains.

Paddy fields are terrestrial ecosystems that represent a favorable environment for the growth of blue-green algae. Members of genus Anabaena Bory ex Bornet et Flahault are the most important genera of filamentous heterocystous blue-green algae in these terrestrial ecosystems. In the present study, Anabaena specimens were obtained from paddy field soils of the seven main rice cultivation provinces situated in the north, centre, south, west and east of Iran from April 2008 to May 2010. For the isolation and identification of these taxa, algal cultures were developed by growing the specimens in a nitrate free BG-11 medium. Identification was carried out by morphometric and molecular methods (16S rRNA gene sequencing). Thirty six morphological characters and numerical taxonomic methods were used for classifying the various species of this genus. Numerical taxonomic studies were performed on 34 populations of 13 Anabaena morphospecies. A cluster analysis and principal component analysis was performed using MVSP software and the rate of resemblance among the species recognized. The results showed that populations of each species are placed close to each other and separate from the other species only on the basis of morphological characters.