جستجوی مقالات مرتبط با کلیدواژه « Cyanobacteria » در نشریات گروه « زیست شناسی »

With the increase of antibiotic resistance, the effort to reduce the consumption of antibiotics by replacing natural active compounds has received much attention in recent years. Cyanobacteria are highly diverse and contain metabolites with medicinal, nutritional and antimicrobial properties.

I In this study, the effect of Spirulina platensis extract on two Gram-positive bacteria Staphylococcus aureus subsp.marcescens and Bacillus subtilis subsp.subtilis (bscillus natto), two Gram-negative bacteria Escherichia coli and Klebsiella pneumoniae and two fungi Penicillium and Aspergillus niger. was investigated. Spirulina platensis hydroalcoholic extract was prepared by maceration method and its antimicrobial activity was evaluated by disk and agar well diffusion methods.

The results showed that the growth of Gram-positive Bacillus was inhibited by Spirulina extract and Staphylococcus aureus showed no sensitivity to the existing Spirulina. Generally, gram positive bacteria were more sensitive than gram negative bacteria. Also, Aspergillus niger showed more antifungal activity than Penicillium. The supernatant showed better results than the hydroalcoholic extract, and diameter the inhibition zone was from 1 to 15 mm.

In general, due to the increasing resistance of pathogenic fungi to common antifungals, it is recommended that with more research on Spirulina microalgae, the antimicrobial compounds of this algae can be used in the treatment of infectious and fungal diseases.

The increase in cancer mortality as a result of excessive use of chemical drugs has made it one of the deadliest diseases worldwide. For this reason, most of the research today is focused on natural medicinal products. As a result, the aim of this article is to review the anticancer properties of cyanobacteria in the pharmaceutical and medical industry. To write this article, both the experiences and articles of the authors of the article and the latest articles available in the Web of Science, Pub Med, Google Scholar, Scopus and ScienceDirect databases have been used. Natural products are an important source of new medicinal compounds that not only have medicinal value, but are also used as building models for creating synthetic analogs. In the meantime, secondary marine metabolites extracted from cyanobacteria as a desirable source of potential new medicinal active compounds have structural diversity and diverse biological activities such as anti-inflammatory, antiviral, antimicrobial and anti-tumor properties. This review article examines the potential of compounds and metabolites of cyanobacteria as anticancer drugs and examines their chemical structure and mechanisms of actionof action.

Cyanobacteria are the oldest oxygenic photoautotrophs on earth with a wide ecological distribution. They increase soil productivity by affecting its physicochemical properties. Increasing the application of chemical fertilizers is harmful. Therefore, it has become necessary to look for alternative renewable resources to meet at least a part of the demand for crops. In this study, aimed at increasing the efficiency of cyanobacterial biofertilizer, the effects of nitrogen, phosphorus and potassium elements in the form of urea, superphosphate and potassium chloride fertilizers were evaluated on nitrogen fixation activity measured by gas chromatography, nifH gene expression and the growth of cyanobacterium Aliinistoc sp. In general, the growth and nitrogen fixation activity of the sample decreased as the concentration of nitrogen and phosphorus sources increased. The most effect of nitrogen source was on nitrogenase activity, and at the end of the experimental period compared to the beginning (before treatment), the amount of nitrogenase activity decreased 50 and 100% in the presence of 10 and 100 mg/L urea, respectively. Phosphorus had a significant effect on the growth of the sample, and at the highest concentration of superphosphate (500 mg/L), growth declined about 80%. On the other hand, potassium especially at the lowest concentration (125 mg/L), significantly increased growth by about 20% and doubled nitrogenase activity. In addition, the evaluation of nifH gene expression confirmed the pattern of nitrogenase activity. In general, the results of this study indicate that the dosage of elements used in combination with cyanobacterial biofertilizers should be considered.

Biological soil crusts including cyanobacteria, fungi, bacteria, actinomycetes, algae, viruses, mosses, lichens, and plants are formed on the soil surface. Cyanobacteria are key microorganisms in the formation of the biological soil crust, especially in arid and desert areas. Cyanobacteria increase carbon and nitrogen content in soil via increasing colony formation and Exopolysaccharide (EPS) production and play an important role to strengthen soil structure especially in poor soil and prevent it from eroding.

In the present study, three cyanobacteria with the highest secreted carbohydrate production were selected among 19 isolates of different provinces’ soil. The amount of carbohydrate production of the selected strains was determined by using the phenolic sulfuric acid method. Then, three selected strains, with the highest amount of secreted carbohydrate were inoculated to the pot filling with poor soils. After 7 weeks of cyanobacterial inoculation, some physical and chemical alterations of the soil were measured. Furthermore, the rate of formation of the biological soil crust and the adhesiveness of the soil particles were microscopically investigated.

The carbohydrate content was 86.66 µg/ml for Anabaena sphaerica, 55. 91 µg/ml for Geitlerinema.sp, and 64.19 µg/ml, for Nostoc pruniforme. The results of the study also show that these three strains are capable of forming biological soil crust on the soil surface.

Anabaena sphaerica, due to its high growth rate, more biomass production, and more secreted carbohydrates increased soil nitrogen and carbon content, as well as better formation of biological soil crust was selected for further investigation. This strain improved some soil texture characteristics and probably it can have a positive effect on soil fertility.

Spirulina is a photosynthetic cyanophyte that can grow in high intensity sunlight and very alkaline conditions and high temperatures. This algae contains vitamin supplements in the diet. Spirulina will be introduced as a complete food source in the near future. In fact, one of the most important problems in the food industry is the use of synthetic preservatives and synthetic food additives that increase the risk of cancer. Therefore, efforts are being made around the world today toisolate new and safe antioxidants from natural sources. Among these, the natural products (secondary metabolites) of cyanobacteria are an important source of new drug compounds.  Natural products not only have medicinal value themselves, but are also used as building models to create synthetic analogues. The chemical composition of Spirulina includes protein (70-55%), carbohydrates (25-25%), essential fatty acids (18%), vitamins, minerals and pigments such as   carotene, chlorophyll a and phycocyanin. Because there is great potential for exploiting this algae and turning it into a dietary supplement in the production of a variety of food products such as cookies and biscuits, ice cream and cream cheese, and that in a small volume of this algae, it can be used as a golden key in nutrition. In this article, considering the potential potential of  Cyanobacterium Spirulina, the morphological structure, life cycle, nutritional composition,  antiviral activity, anti-cancer, anti-inflammatory, safety, anti-nephrotoxicity properties, increased visual acuity, weight loss and Blood lipids are treated. Obviously, the introduction of valuable properties of cyanobacteria Spirulina can be a suitable substitute for many antimicrobial compounds and synthetic antioxidants that not only pose no risk to the consumer, but can also  improve consumer health. On the other hand, since the present study reviews the latest findings on cyanobacteria Spirulina, it is hoped that this study could pave the way for the introduction of    edible microalgae with healing properties that can be used in the food industry.

Algae are the most important group of organisms which considerably affect the water quality. Although algae constitute one of the fundamental parts of the aquatic food chains, only few researches deal with the freshwater algae of Iran. Filamentous algae are important components of the river vegetation. The Balikhlou River is utilized as a source to obtain drinking water for the city of Ardabil, therefore, the algae flora of this river was studied and a total number of 18 taxa of filamentous algae were determined, of which nine species were belonged to the Cyanophyceae class of Cyanobacteriae, while five speciesof which were belonged to the Chlorophyta. In addition, four species were recorded for the first time from Iran, i.e., Audouinella eugenea, Arthrospira gigantea, Homoeothrix janthina and Tychonema bourrellyi.

Cyanobacteria, microscopic organisms have similar characteristics to prokaryotes and eukaryotes, which are very popular in biotechnology research today and are able to produce a wide range of highly valuable organic compounds. However, many strains of cyanobacteria still remain unknown in Iran, a group that is dedicated to freshwater (ponds or springs and streams) and a group that is related to terrestrial habitats. This is in many cases due to the fact that the specific cultivation methods of cyanobacterial strains are not well known. In fact, culturing the strains of axenic cyanobacteria, free of any bacteria or other pathogens, will allow many research activities to be performed in various genetic and molecular fields. In this article, in order to get acquainted with different media cultures for different types of cyanobacterial strains, the correct and accurate method of isolation, cultivation and purification of aquatic and terrestrial, cyanobacteria will be explained.

Among the photosynthetic microorganisms, cyanobacteria belonging to the genus Fischerella appear particularly promising for new polysaccharides producing strains. Extracellular polysaccharides (EPS) serve as a boundary to the immediate environment and play a protective role against antimicrobial agents. That iswhy cyanobacteria are so popular in the industry today as thickeners or floating agents, heavy metal absorbers, or in the case of sulfate polysaccharides as bioactive substances. This is an advantage over other polysaccharides extracted from plants or other macroalgae. There are many factors  affecting cell growth and metabolite accumulation in cell cultures. However, there is insufficient knowledge about the factors affecting maximal EPS biosynthesis and antibacterial activity. In this regard, in this paper, the effect of some physical, environmental, and nutritional factors on the simultaneous production of exopolysaccharide by Fischerella sp. SH.A was investigated in order to select the best cultivation conditions for the industrial application of exopolysaccharides.

In this study, the cyanobacterium isolated from the fresh water of Golestan province was undertaken with the aim of investigating the key factors regulating EPS biosynthesis and antibacterial activity. After the morphological and molecular identification, the possible correlations between the type of stress and the amount of polysaccharides production were also investigated.

The obtained results indicated that EPS production and antibacterial activity were highly dependent on the culture conditions and light intensity. Furthermore, the production of exopolysaccharides in non-diastrophic conditions was highly correlated with the concentration of nitrate up to 500 mM and the illumination of 50 or 150 microeinsteins per second per square meter. 

Discussion and conclusion:

Since cyanobacterial extracellular polysaccharides are interesting from the biotechnological point of view, considering some other parameters are of crucial importance for the maximization of EPS production in this genus.