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The prevailing conditions for the production, storage, and sale of traditional cheese seem to increase the probability of microbial contamination. Escherichia coli and Staphylococcus aureus are among the bacteria that may cause major complications such as diarrhea, hemolytic uremic syndrome (HUS), food poisoning, and gastrointestinal infections in cheese consumers. The use of food coloring to enhance the microbial load of food products, as an innovative and cost-effective biological control, is one of the most efficient methods in managing the production, storage, and quality of food. Extracted naturally from Spirulina sp., phycocyanin is widely used in various pharmaceutical, food, cosmetic and health industries. This is the first attempt to investigate the possible effect of adding phycocyanin pigment into traditional cheese, in order to improve-the nutritional value, quality and shelf life of traditional cheese. This study collected five different types of traditional cheese from different localities in Iran. The researcher immersed the samples in concentrations of 1%, 1.5% and 2% phycocyanin pigment. After identifying the existing bacteria, the possible effect of the pigment on the total number of bacteria, as well as the number of E. coli and S. aureus, were evaluated within 15 days. The study used Ferric ion reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and nitric oxide trapping with the sensory testing in order to determine the amount of protein, fat, ash, moisture, and antioxidant properties. Statistical analyses showed that, compared to the control group, the concentration of phycocyanin rose when the number of bacteria decreased and antioxidant activity increased in all types of cheese. The results revealed a significant increase in the amount of protein (93%), fat (80%), moisture (100%), and ash (67%). In addition, the highest consumer satisfaction was observed on day 1 and days 7 and 15; cheese with a concentrations of 1.5% and 2% pigments were preferred.

Background: Cyanobacteria is an excellent candidate for discovering bioactive compounds with applications in pharmaceutical industries. Nowadays, the major bioactive metabolites isolated from cyanobacteria are polymerized, nonribosomal peptides (NRPS), or hybrids of both. Despite numerous studies on the gene distribution of bioactive compounds, no studies have been conducted on the cyanobacteria strains found in the Tehran cascade. Objectives: This monitoring study aimed to study the secondary structure of the protein and molecular phylogeny of polypeptides synthase genes and nonribosomal peptides along with the 16S rRNA gene. Methods: In this study, 20 strains of cyanobacteria found in the Tehran Cascade were identified based on a 16rRNA gene sequence. The PCR of the nonribosomal peptides (NRPS) and polyketide synthase (PKS) genes was performed using molecular techniques to analyze the phylogenetic genes responsible for secondary metabolite production. Bioinformatics software was used to predict the composition of peptides, activated amino acids, and signature sequences of the NRPS adenylation module. Finally, the strains studied in the Alborz Herbarium Microbial Culture Collection (CCC) were kept at the Azad Islamic University, Science and Research Unit. Results: The NRPS and PKS genes were found in some strains. Furthermore, the bioinformatics analyses revealed the type of natural compound, the signature sequences, and the predication of the activated amino acid. Clustering of NRPS and PKS protein sequences showed no clear phylogenetic correlation between adenylation domains and the type of activated amino acid, indicating wide diversity within adenylation domains. Conclusions: The biological analysis of polypeptide synthase and nonribosomal peptide synthetases genes may help estimate species that produce natural products and the possible role of these enzymatic complexes in the bio-synthesis of bioactive compounds in the pharmaceutical industry.

A qanat or kariz is a slightly sloping underground aqueduct used to transport water from wells or aquifers to the surface for irrigation and drinking supply. A cyanobacterial strain was isolated from a cyanobacterial mat colonizing the wall of a qanat in Golestan province, Gorgan City, Iran. Fragments of 16S rRNA, mcyG, and mcyD genes were amplified and sequenced, as well as the 16S-23S internal transcribed spacer (ITS). After microscopic examination, the isolate was related to a morphotype of Nostoc sensu lato group, with similar characteristics to Desmonostoc. The 16S rRNA phylogenetic analysis placed the isolate into the typical cluster of the recently proposed genus Desmonostoc. Morphological analysis revealed distinctive characteristic and secondary 16S-23S rRNA structures derived from comparative analysis, which did not match known species of Desmonostoc. These results lead us to propose a novel Desmonostoc species, Desmonostoc alborizicum, which was described and compared with similar taxa. Furthermore, for the first time a potentially toxic species of Desmonostoc was isolated from a water supply, since the mcyD and mcyG genes of the microcystin synthetase (mcy) cluster were successfully sequenced. Using mass spectrometry, detectable amounts of the hepatotoxin microcystin-LR and -RR, along with demethylated variants, were present in cell extracts of the Desmonostoc strain. Our findings contribute to a deeper understanding of the diversity, systematics, and occurrence of the genus Desmonostoc.

A new species of heterocytous cyanobacterium Dulcicalothrix alborzica sp. nov. (Calotrichaceae) was isolated from Iran and described following a polyphasic approach. Morphological examination indicated that the strain, initially called "Alborzica", belonged to the genus Calothrix. Nonetheless, 16S rRNA gene analysis showed that "Alborzica" were within the Dulcicalothrix cluster. In order to confirm the taxonomic position of this new taxon, rbcL and rpoC1 phylogenies were inferred. Results confirmed identity of "Alborzica" supporting the 16S rRNA phylogeny. Analysis of the secondary structures of 16S-23S Internal Transcribed Spacer (ITS) revealed that "Alborzica" had unique structure compared with known Dulcicalothrix spp. Therefore, based on the morphology and thorough molecular analysis, "Alborzica'' should be considered a novel species in the genus Dulcicalothrix.

Phycobiliproteins are accessory photosynthetic pigments with a tetrapyrrole structure derived from bacterial strains that are organized on a thylakoid membrane inside a structure called phycobilisomes. Phycobiliproteins have been extensively commercialized in the manufacture of fluorescent probes for clinical and immunological analysis, in addition to their ability to dye with proven antioxidant and medicinal properties. Phycocyanin, Phycoerythrin and Allophycocyanin are the main types of phycobiliproteins that are widely used as useful food supplements today; however, in Iran, the true value of this natural pigment with bioactive properties has not been realized. Todays, the use of artificial colors and antioxidants in food product has led to an increase in cancer in many people. Therefore, awareness of the presence of natural food pigments of natural origin is of particular important. On the other hand, since so far no review article on extraction, separation and purification as well as evaluation of the biological activity of the pigment Phycoerythrin and Phycocyanin, has been published in Iran, so such review articles can pave the way for the introduction of natural edible pigments from cyanobacteria are considered to be usable in the food industry. Therefore, the purpose of this review article is to introduce the structure, function, biosynthesis and different methods of extraction of Phycobiliproteins in industrial dimensions along with different applications of Phycocyanin in food and pharmaceutical industries.

Cyanobacteria, an abundant source of natural products with a broad diversity of secondary metabolites, have emerged as a novel resource for the progression of synthetic analogs. Due to the rise of antibiotic resistance, there is a need for new medications and cyanobacteria-derived compounds have shown promising important alternatives for new therapeutics. These secondary metabolites are produced through nonribosomal peptide synthetase (NRPS), polyketide synthase (PKS), and mainly through mixed NRPS-PKS enzymatic systems. Current research is focused on the exploitation of cyanobacteria for the production of bioactive metabolites. Screening of cyanobacteria for pharmaceutically active compounds has received increasing attention; however, limited knowledge is available on biosynthetic mechanisms that would enhance the drug discovery process and culture-based production of desired metabolites. Overall, there is a promising outlook that cyanobacterial secondary metabolites will become alternatives for the development of new medications in a near future with enhanced pharmacological and pharmacokinetic properties.

Lavasan Lake is one of the main water sources for Tehran metropolitan region, besides irrigating 30,000 ha of agricultural land. Cases of animal deaths linked to water ingestion prompted us to study the occurrence of cyanobacteria-related toxic compounds. We investigated the production of microcystins (hepatotoxins) and homoanatoxin-a (neurotoxin) by isolated heterocyst‐forming cyanobacteria using LC-MS and MALDI-TOF mass spectrometry coupled with the detection of biosynthetic gene cluster sequences. The isolates were identified previously by combining morphological analysis and the 16S rRNA gene sequencing. Homoanatoxin-a was detected by LC-MS run at a retention time of 16.3 min, and the protonated molecular ion (m/z 180) was trapped and fragmented by mass spectrometry. The presence of the toxin-producing anaC gene was found in only one Anabaena isolate in agreement with the toxin homoanatoxin-a production. This is the first report of a neurotoxin-producing cyanobacterium isolated from Lavasan Lake.

High levels of nitrate and nitrite in groundwater lead into environmental issues and nitrate poisoning causes unpleasant consequences in human bodies. The present study was conducted to evaluate the concentration of nitrate, nitrite, and nitrate-reducing bacteria in treated drinking water in five areas in Tehran using optical spectroscopy. The results of one-way ANOVA showed that the average concentrations of nitrate in summer and autumn are significantly higher than those of nitrite. Moreover, the highest mean of concentration of nitrate and nitrate was observed in the west of Tehran in autumn 2016 (1.2±0.01 and 4.6±0.02 mg. L-1). On the other hand, the lowest mean was found in the south of Tehran (0.06±0.02 and 0.001±0.01 mg. L-1). However, only in the southern region of Tehran, signs of Pasteurella sp. and Acinetobacter sp. were observed. Additionally, the results of the Duncan test indicated no significant differences concerning nitrate concentration in the morning, noon, and at night in the southern, eastern, and central regions in autumn and summer. The samples of the north, east, and center had the lowest risk and, in the west, and south of Tehran, the highest risk and adverse effects of nitrite and nitrate were observed. Although the average concentration of nitrate and nitrite in all these areas, except for the west of Tehran, was less than the standard of the WHO and the latest national standard, protection of groundwater resources against the entry of pollutants treatment networks to prevent the increase of these ions in water seems to be necessary.

Spirulina is a single-cell protein rich in all essential nutrients and vitamins and can be used to produce functional food. Spirulina is a single-cell protein rich in all essential nutrients and vitamins and can be used to produce functional food. In fact, one of the most important problems in the food industry is the use of synthetic food additives that increase the risk of cancer. Therefore, efforts are being made around the world today to isolate new and safe antioxidants from natural sources. Among these, the natural products of cyanobacteria are an important source of new drug compounds. Natural bioactive products not only have medicinal value themselves but are also used as building models to create synthetic analogs. 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. 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. In this review, we have discussed the important nutrient, bioactive properties, and immunological applications of Spirulina. The current research suggests that spirulina supplementations have been accepted by global accreditation as a safe nutritional and dietary supplement.

Peptide-based therapies offer the potential opportunity for dangerous diseases such as cancer. Anticancer peptide and their strategies to defend against cancer cell lines are found throughout nature. To date, numerous of these biomolecules have been described, and, with emphasis on their potential function, more and more peptides are likely to be found. There is a wide range of traditional approaches such as chemotherapeutic drugs in the first line of cancer therapy, but, as the century progresses, a greater emphasis has been drawn to more effective and less destructive approaches such as natural compounds which are extracted from natural resources. A vast report on peptides extracted from natural resources has been reported and published which their cytotoxic activity against cancer cells have investigated. Here we focus on providing information on potential uses of natural peptides from terrestrial and marine environments (including fungal, animal, insects and amphibians). The data were collected from original research and review articles from peer-reviewed journals. A total of 174 articles are cited in the present review summarizing the recent natural peptides with anticancer activity from natural resources such as fungal, animal, marine, and so on. Also, their mechanisms, experimental condition (in vivo and in vitro), cancer cell lines and peptides sources are summarized in Table 1. The present study provides general and recent information on naturally occurring peptides with cytotoxicity against cancerous cells. We mainly emphasized on their natural originality and effective cytotoxicity toward cancer cell lines. Also, the advantages and drawbacks of using these peptides are mentioned. Due to the importance of cancer and their traditional therapies, utilizing such peptides can take into account and adsorb more medical importance.

Ajigol wetland is a complex ecosystem in Northern Iran, which is ecologically important because contains up to 50% of threatened native plant species and aquatic organisms. Increasing of fish death and animal poisonings has led to an increased research interest and public awareness of harmful cyanobacterial blooms in this area. In the present work, we characterized a filamentous heterocyst-forming cyanobacterium morphologically and molecularly. Coupled with the 16S rRNA gene sequence, the rbcL gene and the 16S–23S internal transcribed spacer (ITS) secondary structures were analysed. Further, sequences of the mcyD and mcyG genes of microcystin synthetase (mcy) cluster were PCR amplified and sequenced. The secondary structures of the D1-D1’, BOX-B and V3 regions provided a better resolution of the studied strain. The sequenced mcy genes involved in the microcystin synthesis contribute to extend the understanding of the evolution of mcy genes in the genus Fischerella.

Proper packaging is an essential issue in seafood safety leads to the preservation of food quality and extending the shelf life. In this study, fabrication and characterization of LDPE/Ag/TiO2 and LDPE/Ag + Cu/TiO2 nanocomposite films for application in Nile Tilapia packaging were evaluated. After investigation of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), disk diffusion test, minimum inhibitory concentration, and minimum bactericidal concentration, the antimicrobial effect of produced nanocomposite films was evaluated on the Tilapia fish samples stored at 4 °C and − 20 °C for 5 and 10 days. Chemical features (pH, protein and fat concentrations, and free fatty acid profile) of the Tilapia fish covered with the produced nanocomposites and nanoparticle migration were also assessed. EDS and SEM techniques confirmed the presence of nanoparticles on the polymer surface and their relative homogeneity. The antibacterial tests of LDPE/Ag + Cu/TiO2 nanocomposite film exhibited strong antibacterial activities against Escherichia coli and Listeria monocytogenes bacteria (P = 0.000). The microbiological tests revealed that Ag + Cu-contained film had significantly higher antimicrobial efficacy on the Nile Tilapia samples (P

A cyanobacterial mat colonizing the wall of a qanat was found to be responsible for damages affecting the passage of water through the water supply system in Golestan province, Gorgan city, Iran. A qanat or kariz is a slightly sloping underground aqueduct used to transport water from water wells or aquifers to the surface for irrigation and drinking supply. A cyanobacterial strain was isolated from the mat and grown in BG11 liquid medium. Fragments of 16S rRNA, mcyG and mcyD genes were amplified and sequenced, as well as the 16S-23S internal transcribed spacer (ITS), from which secondary structures were analyzed. The obtained molecular data, together with morphological and physiological observations, were used to describe the new organism. The isolate was related to a morphotype of Nostoc sensu lato group, with similar characteristics of Desmonostoc, after microscopic inspections. The 16S rRNA phylogenetic analysis placed the isolate into the typical cluster of the recently proposed genus Desmonostoc. Morphological analysis revealed distinctive characteristic and secondary structures of 16S–23S rRNA (D1-D1´ and Box-B regions) derived from comparative analysis, which did not match known species of Desmonostoc. These results lead us to propose a novel Desmonostoc species, Desmonostoc alborizicum, which was described and compared with similar taxa. Furthermore, for the first time a potential toxic species of Desmonostoc was isolated from water supply, since the mcyD and mcyG genes of microcystin synthetase (mcy) cluster was successfully sequenced. The presence of the microcystin was confirmed by chemical analyses that also lead to the discovery of numerous other cyanobacterial secondary metabolites. We recognized substantial amounts of the potent microcystin variant microcystin-LR present in cell extracts of the Desmonostoc strain. Our findings contribute to a deeper understanding of diversity, systematics, and occurrence of Desmonostoc genus.

Abstract: Humans have used algae for hundreds of years to make various products viz. agar, fertilizer, food, and pigments. Algae are also used in bioremediation to clean up polluted water and as essential laboratory tools in genomics, proteomics, and other research applications such as environmental warnings. Several special features of algae, including the oxygenic photosynthesis, higher yield in biomass, growth on the non-arable lands, their survival in a wide range of water supplies (contaminated or filtered waters), the production of necessary byproducts and biofuels, the enhancement of soil productivity, and the greenhouse gas emissions, etc. altogether rendered them as vital bio-resources in the sustainable development. Algae and bacteria have been assumed to coexist from the early stages of the development of the earth, and a wide variety of interactions were observed between them which have influenced the ecosystems ranging from the oceans to the lichens. Research has shown that bacteria and algae interact synergistically, especially roseobacter- algae interactions being the most common. These interactions are common to all ecosystems and characterize their primary efficiency. The commercialization of algae for industrial purposes, an important field, is also influenced by this interaction which frequently results in bacterial infections among the consumers. However, the recent findings have revealed that the bacteria improve algal growth and support flocculation which are very crucial in algal biotechnology. Some of the most exciting advancements in the area of algal biotic interactions and potential difficulties were reviewed in this article. Information gleaned in this study would provide a firm foundation for launching more contemporaneous research efforts in understanding and utilizing the algal species in biotechnology industries and medical sectors.

An aerobic Gram-stain-negative, curved rod-shaped and non-spore-forming bacterial strain (NBU2194T) was isolated from seawater collected in an intertidal zone in Ningbo, Zhejiang Province, PR China. It was motile though a single polar flagellum and grew at 20–42 °C (optimum, 30 °C), in 0–2.0 % NaCl (0 %, w/v) and at pH 5.0–9.0 (pH 6.0–7.0). The sole respiratory quinone was ubiquinone-8. The major cellular fatty acids were C16 : 0, C16 : 1 ω7c and/or C16 : 1 ω6c. The polar lipids contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified phospholipid and two unidentified aminophosphoglycolipids. A phylogenetic analysis based on 16S rRNA gene sequences and 65 genomic core genes showed that strain NBU2194T formed a distinct lineage in the family Alteromonadaceae . The genome of strain NBU2194T was 4 913 533 bp with a DNA G+C content of 43.9 mol% and coded 3895 genes, 12 rRNA genes and 47 tRNA genes. The average nucleotide identity, amino acid identity and digital DNA–DNA hybridization values between strain NBU2194T and related species of Alteromonadaceae were below the threshold limit for prokaryotic species delineation. NBU2194T could be distinguished from other genera in the family Alteromonadaceae based on phenotypic, chemotaxonomic and genomic characteristics. On the basis of the polyphasic taxonomic evidence collected in this study, strain NBU2194T is considered to represent a novel genus and species in the family Alteromonadaceae , for which the name Paraneptunicella aestuarii is proposed. The type strain is NBU2194T (=KCTC 82442T=GDMCC 1.2217T).

Background In the present research, challenges arose when many reports have been published on the poisoning of humans due to the ingestion of crops of Crataegus plants contaminated with cyanobacterial toxins. The discovery of several poisonings around agricultural zones prompted us to study the toxic compounds in a strain of Neowestiellopsis which is the most abundant in the agricultural zones of Kermanshah province of Iran, using a polyphasic approach. Molecular procedure was followed to study these strains deeply. Material and methods To elucidate their systematic position, besides the 16S rRNA gene, the analyses of molecular toxicity markers, namely nos, mcy G, mcy D and internal transcribed spacer (ITS), were also used. Results Based on the results, for the first time, we record the presence of a gene cluster coding for the biosynthesis of a bioactive compound (Nostopeptolides) that is very rare in this family and the presence of toxic compounds (microcystin), which might account for the poisoning of humans. Conclusions This case is the first observation of a toxic soil strain from the genus Neowestiellopsis from agricultural fields in Iran.

Harmful cyanobacterial blooms are increasing and becoming a worldwide concern as many bloom-forming cyanobacterial species can produce toxic metabolites named cyanotoxins. These include microcystins, saxitoxins, anatoxins, nodularins, and cylindrospermopsins, which can adversely affect humans, animals, and the environment. Different methods to assess these classes of compounds in vitro and in vivo include biological, biochemical, molecular, and physicochemical techniques. Furthermore, toxic effects not attributable to known cyanotoxins can be observed when assessing bloom material. In order to determine exposures to cyanotoxins and to monitor compliance with drinking and bathing water guidelines, it is necessary to have reliable and effective methods for the analysis of these compounds. Many relatively simple low-cost methods can be employed to rapidly evaluate the potential hazard. The main objective of this mini-review is to describe the assessment of toxic cyanobacterial samples using in vitro and in vivo bioassays. Newly emerging cyanotoxins, the toxicity of analogs, or the interaction of cyanobacteria and cyanotoxins with other toxicants, among others, still requires bioassay assessment. This review focuses on some biological and biochemical assays (MTT assay, Immunohistochemistry, Micronucleus Assay, Artemia salina assay, Daphnia magna test, Radionuclide recovery, Neutral red cytotoxicity and Comet assay, Enzyme-Linked Immunosorbent Assay (ELISA), Annexin V-FITC assay and Protein Phosphatase Inhibition Assay (PPIA)) for the detection and measurement of cyanotoxins including microcystins, cylindrospermopsins, anatoxin-a, saxitoxins, and nodularins. Although most bioassay analyses often confirm the presence of cyanotoxins at low concentrations, such bioassays can be used to determine whether some strains or blooms of cyanobacteria may produce other, as yet unknown toxic metabolites. This review also aims to identify research needs and data gaps concerning the toxicity assessment of cyanobacteria.

Introduction: Cyanobacteria are regarded as good candidates for natural pruduct discovery, with applications in ‎pharmaceuticals industry. The majority of bioactive metabolites have either been polyketides, non-ribosomal ‎peptides, or a hybrid of the two. Despite of several worldwide studies on prevalence of NRPSs, none of them ‎included Iranian cyanobacteria of Lavasan Lake. Therefore, the aim of this study was to show that the presence of ‎these genes correlates with natural product synthesis. ‎Materials and methods:‎‏ ‏In this study, ten cultured fresh water cyanobacteria strains of the Lavasan Lake were ‎identified based on the sequence of 16SrRNA gene. In order to phylogenetic analysis the genes responsible for the ‎production of secondary metabolites, a NRPS PCR was conducted. Bioinformatics software tools were used in ‎order to prediction of peptide compound, amino acid activated and the signature sequences by a specific unknown ‎NRPS A module. Antibiogram bioassays were conducted to detect the presence of antimicrobial effects. Lastly, ‎studied strains have been deposited at the Cyanobacteria Culture Collection (CCC) of herbarium ALBORZ at the ‎Science and Research Branch, Islamic Azad University, Teheran.‎Results: the results showed that NRPS genes are presence in all strains. Morover bioinformatics analysis confirmed ‎the type of natural compound, signature sequences and predicted amino acid. In clusterimg of NRPS protein ‎sequences, there was no clear phylogenetic correlation between adenylation domains and activated amino acid and ‎this result emphasize the variety of adenylation domains. Morover the results of antibiogram bioassays showed ‎that there are positive correlation between the presents of those genes and antimicrobial activity.‎Discussion and conclusion: Sequence analysis indicates the enzymes encoded by these genes may be responsible ‎for the production of different secondary metabolites, such as antibiotics. The presented results prove that fresh ‎water cyanobacterial of Iran are a promising source to yield chemical and pharmaceutical interesting compounds.‎

Cyanobacteria have the ability to produce a wide variety of natural bioactive compounds. In order to reveal the diversity of Cyanobacteria in Iran, and their potential to synthesise various natural products, we isolated 25 strains from different climatic/geographic regions and habitats, and screened the genes that are responsible for the synthesis of natural products (such as nonribosomal peptide synthetase or polyketide synthase and 4-methylproline) by means of PCR. In addition, we analysed adenylation domain substrate specificity from screened NRPS fragments in order to identify peptidic molecules that are produced by the studied strains. The phylogenetic analysis showed the widespread, but sporadic, occurrence of the methylproline biosynthetic pathways in these strains. Our results do not only reveal the chemical diversity that is occurring in these Cyanobacteria of Iran that we isolated, but they also indicate that 4-methylproline biosynthetic genes have a complex evolutionary history in Cyanobacteria, which has been punctuated by a series of ancient horizontal gene transfer events.

Background and Aims: Cyanobacteria are considered as favorable source for new pharmaceutical compounds. To date, the majority of bioactive metabolites isolated from cyanobacteria are either polyketides (PKSs) or non-ribosomal peptides. Despite of several worldwide studies on prevalence of PKSs, none of them included the terrestrial cyanobacteria of the Lavasan. Therefore, this study aimed to detectthe PKS genes and correlation of the presence of these genes with antimicrobial compounds synthesis. Materials and Methods: Morphological and molecular identification of the terrestrial strains was performed after culture and purification. Amplification of polyketide synthase and phylogenetic trees were used for ‎phylogenetic analysis. Nucleotide and protein sequences were deposited in GenBank. Lastly, to show the correlation of this gene with antimicrobial compounds synthesis, antibiogram bioassay was used. Results: Phylogentic analysis revealed that most of the identified 16SrRNA genes and PKS domains had more than 90% similarity to their closest matches in the Gen-Bank. In addition, antibiogram assessment showedthe different pattern of inhibition, indicating the involvement of variety antimicrobial substances. Conclusions: According to the results of this sudy, it seems the antibiogram bioassay and molecular detection of polyketide synthase genes are useful techniques for the assessment of productive species of natural products and the possible role of polyketide synthase enzyme complexes in the biosynthesis of biologically active compounds.

In Iran, polyphasic studies of unicellular cyanobacteria are still scarce, with more emphasis being placed on filamentous cyanobacteria in paddy fields and fresh water regions. In an effort to increase the knowledge of the diversity of unicellular cyanobacteria from paddy fields in Iran, we have isolated and characterized a new unicellular cyanobacterium strain. The strain was studied using a polyphasic approach based on morphological, ecological and phylogenetic analyses of the 16S–23S ITS rRNA gene region. Complementarily, we have searched for the presence of cyanotoxin genes and analysed the pigment content of the strain. Results showed that the strain was morphologically indistinguishable from the genus Chroococcus , but phylogenetic analyses based on the Bayesian inference and maximum-likelihood methods placed the strain in a separated monophyletic and highly supported (0.99/98, posterior probability/maximum-likelihood) genus-level cluster, distant from Chroococcus sensu stricto and with Chalicogloea cavernicola as sister taxa. The calculated p-distance for the 16S rRNA gene also reinforced the presence of a new genus, by showing 92 % similarity to C. cavernicola . The D1–D1′, Box-B and V3 ITS secondary structures showed the uniqueness of this strain, as it shared no similar pattern with closest genera within the Chroococcales. For all these reasons, and in accordance with the International Code of Nomenclature for Algae, Fungi and Plants, we here proposed the description of a new genus with the name Alborzia gen. nov. along with the description of a new species, Alborzia kermanshahica sp. nov. (holotype: CCC1399-a; reference strains CCC1399-b; MCC 4116).

Background Cyanobacteria are ecologically significant prokaryotes that can be found in heavy metals contaminated environments. As their photosynthetic machinery imposes high demands for metals, homeostasis of these micronutrients has been extensively considered in cyanobacteria. Recently, most studies have been focused on different habitats using microalgae leads to a remarkable reduction of an array of organic and inorganic nutrients, but what takes place in the extracellular environment when cells are exposed to external supplementation with heavy metals remains largely unknown. Methods Here, extracellular polymeric substances (EPS) production in strains Nostoc sp. N27P72 and Nostoc sp. FB71 was isolated from different habitats and thenthe results were compared and reported. Result Cultures of both strains, supplemented separately with either glucose, sucrose, lactose, or maltose showed that production of EPS and cell dry weight were boosted by maltose supplementation. The production of EPS (9.1 ± 0.05 μg/ml) and increase in cell dry weight (1.01 ± 0.06 g/l) were comparatively high in Nostoc sp. N27P72 which was isolated from lime stones.The cultures were evaluated for their ability to remove Cu (II), Cr (III), and Ni (II) in culture media with and without maltose. The crude EPS showed metal adsorption capacity assuming the order Ni (II) > Cu (II) > Cr (III) from the metal-binding experiments.Nickel was preferentially biosorbed with a maximal uptake of 188.8 ± 0.14 mg (g cell dry wt) −1 crude EPS. We found that using maltose as a carbon source can increase the production of EPS, protein, and carbohydrates content and it could be a significant reason for the high ability of metal absorbance. FT-IR spectroscopy revealed that the treatment with Ni can change the functional groups and glycoside linkages in both strains. Results of Gas Chromatography-Mass Spectrometry (GC–MS) were used to determine the biochemical composition of Nostoc sp. N27P72, showed that strong Ni (II) removal capability could be associated with the high silicon containing heterocyclic compound and aromatic diacid compounds content. Conclusion The results of this studyindicatede that strains Nostoc sp. N27P72 can be a good candidate for the commercial production of EPS and might be utilized in bioremediation field as an alternative to synthetic and abiotic flocculants.

Purpose: Cyanobacteria are ecologically relevant prokaryotes that can be found in environments contaminated with heavy metals. As their photosynthetic machinery imposes high demands for metals, homeostasis of these micronutrients has been extensively considered in cyanobacteria. So far, most studies have focused on treatment of wastewaters using microalgae leads to remarkable reduction of an array of organic and inorganic nutrients, but what takes place in the extracellular environment when cells are exposed to external supplementation with heavy metals remains largely unknown. Methods: Here, extracellular polymeric substances (EPS) production in strains Nostoc sp. N27P72 and Nostoc sp. FB71 isolated from different habitats are reported and compared. Cultures of both strains, supplemented with either glucose, sucrose, lactose or maltose showed that production of EPS and cell dry weight was boosted by maltose supplementation. Result: Nostoc sp. N27P72 which was isolated from lime stones was higher, resulting in 9.1 ± 0.05 µg/ml and 1.01 ± 0.06 g/l in EPS and cell dry. The cell cultures tested for their ability to remove Cu(II), Cr(III) and Ni(II) in media culture containing the maltose and without maltose as control culture. Remarkably, we showed that although these elements can be toxic, supplementing the media culture can effectively sequester their toxic effects by increasing the production of EPSs, carbohydrates and total soluble proteins in comparison to control. The crude EPS showed metal adsorption capacity assuming the order Ni(II)> Cu(II)> Cr(III) from metal-binding experiments. Nickel was preferentially biosorbed with a maximal uptake of 188.8 ± 0.14 mg (g cell dry wt) -1 crude EPS. FT-IR spectroscopy revealed treatment with Ni made changes in the functional groups and glycoside linkages in both strains. Results of Gas Chromatography Mass Spectrometry (GC–MS) to determine the biochemical composition of Nostoc sp. N27P72 showed that strong Ni(II) removal capability is suspected to be associated with the high Cyclotrisiloxane and 1,2-Benzenedicarboxylic acid content. Conclusion: The results of these investigates specified that strains Nostoc sp. N27P72 is good candidates for the commercial production of EPS and might be utilized in bioremediation field as an alternative to synthetic and abiotic flocculants.

The recent Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), positive-sense RNA viruses, originated from Wuhan City in December 2019 and propagated widely globally. Hence, the disease caused by this virus has been declared as a global pandemic by the WHO. As of 18th February 2021, at least seven different vaccines across three platforms have been rolled out in countries and more than 200 additional vaccine candidates have been in development, of which more than 60 are at the stage of the clinical development. So far, Most of the approved vaccine manufacturers are Pfizer, AstraZeneca, and Serum Institute of India, which have been finalized by WHO. Synthetic drug-associated complications have evoked scientific attention for natural product-based drugs. There has been a surge in the antiviral compounds from natural resources along with some therapies. Cyanobacteria are the fruitful reservoir of many metabolites like sulfated polysaccharides and lectins that possess strong antiviral activities and immunity boosting effects. However, the research in this field has been relatively under-developed. The current research highlights important features of cyanobacterial antiviral biomaterials, benefits and drawbacks of cyanobacterial drugs, challenges, future perspectives as well as overview of drugs against COVID-19. In addition, we have described mutated variants and transmission rate of coronaviruses. The current research suggests that cyanobacterial species and their extracts have promising applications as potentially antiviral drug biomaterials against COVID-19. Communicated by Ramaswamy H. Sarma.

Harmful cyanobacterial blooms are increasing and becoming a worldwide concern as many bloom-forming cyanobacterial species can produce toxic metabolites named cyanotoxins. These include microcystins, saxitoxins, anatoxins, nodularins, and cylindrospermopsins, which can adversely affect humans, animals, and the environment. Different methods to assess these classes of compounds in vitro and in vivo include biological, biochemical, molecular, and physicochemical techniques. Furthermore, toxic effects not attributable to known cyanotoxins can be observed when assessing bloom material. In order to determine exposures to cyanotoxins and to monitor compliance with drinking and bathing water guidelines, it is necessary to have reliable and effective methods for the analysis of these compounds. Many relatively simple low-cost methods can be employed to rapidly evaluate the potential hazard. The main objective of this mini-review is to describe the assessment of toxic cyanobacterial samples using in vitro and in vivo bioassays. Newly emerging cyanotoxins, the toxicity of analogs, or the interaction of cyanobacteria and cyanotoxins with other toxicants, among others, still requires bioassay assessment. This review focuses on some biological and biochemical assays (MTT assay, Immunohistochemistry, Micronucleus Assay, Artemia salina assay, Daphnia magna test, Radionuclide recovery, Neutral red cytotoxicity and Comet assay, Enzyme-Linked Immunosorbent Assay (ELISA), Annexin V-FITC assay and Protein Phosphatase Inhibition Assay (PPIA)) for the detection and measurement of cyanotoxins including microcystins, cylindrospermopsins, anatoxin-a, saxitoxins, and nodularins. Although most bioassay analyses often confirm the presence of cyanotoxins at low concentrations, such bioassays can be used to determine whether some strains or blooms of cyanobacteria may produce other, as yet unknown toxic metabolites. This review also aims to identify research needs and data gaps concerning the toxicity assessment of cyanobacteria.

Different biological methods based on bioactivity are available to detect cyanotoxins, including neurotoxicity, immunological interactions, hepatotoxicity, cytotoxicity, and enzymatic activity. The mouse bioassay is the first test employed in laboratory cultures, cell extracts, and water bloom materials to detect toxins. It is also used as a traditional method to estimate the LD50. Concerning the ease of access and low cost, it is the most common method for this purpose. In this method, a sample is injected intraperitoneally into adult mice, and accordingly, they are assayed and monitored for about 24 hours for toxic symptoms. The toxin can be detected using this method from minutes to a few hours; its type, e.g., hepatotoxin, neurotoxin, etc., can also be determined. However, this method is nonspecific, fails to detect low amounts, and cannot distinguish between homologues. Although the mouse bioassay is gradually replaced with new chemical and immunological methods, it is still the main technique to detect the bioactivity and efficacy of cyanotoxins using LD50 determined based on the survival time of animals exposed to the toxin. In addition, some countries oppose animal use in toxicity studies. However, high cost, ethical considerations, low-sensitivity, non-specificity, and prolonged processes persuade researchers to employ chemical and functional analysis techniques. The qualitative and quantitative analyses, as well as high specificity and sensitivity, are among the advantages of cytotoxicity tests to investigate cyanotoxins. The present study aimed at reviewing the results obtained from in vitro and in vivo investigations of the mouse bioassay to detect cyanotoxins, including microcystins, cylindrospermopsin, saxitoxins, etc.

The general overview aimed to increase the current knowledge interactions between dehydrogenase enzymes and nanoparticles, and introduce dehydrogenases for industrial and health purposes. Nanoparticles (NPs) are particles constituting from 1 to 100 nm based on their size with a surrounding interfacial layer. Nanoparticle-Protein interactions include covalent and non-covalent attachments. Several dehydrogenase enzymes (e.g., alcohol dehydrogenase, lactate dehydrogenase, alanine dehydrogenase, glutamate dehydrogenase, leucine dehydrogenase, phenylalanine dehydrogenase, and malate dehydrogenase) are used for immobilization by nanoparticles. Such as magnetic nanoparticles and quantum dots, represent attractive model systems for biological enzyme assemblies and design of bioanalytical sensors. Further, bioconjugation of nanoparticles with dehydrogenase enzymes has broad applications in biocatalysis and nanomedicine for drug discovery. However, studies on the characterization of nanoparticle-enzyme complexes accept apparent that the anatomy and action of enzymes are afflicted by the chemistry of nanoparticle ligand, size, actual, and labeling methods. Moreover, the nanoparticle-protein conjugation revealed increased/decreased enzymatic activity due to nanoparticle features. Thus, this work reviewed the findings of nanoparticle-enzyme interactions for nanotechnology applications and conjugation techniques. We also highlight several challenges associated with the nanoparticle-enzyme interactions, including stability and reusability of the enzymes in nanoparticle-enzyme formation.

Cyanobacteria are well recognised as producers of a wide range of natural compounds that are in turn recognised as toxins that have potential and useful applications in the future as pharmaceutical agents. The order Nostocales, which is largely overlooked in this regard, has become increasingly recognised as a source of toxin producers including Anabaena, Nostoc, Hapalosiphon, Fischerella, Anabaenopsis, Aphanizomenon, Gloeotrichia, Cylindrospermopsis, Scytonema, Raphidiopsis, Cuspidothrix, Nodularia, Stigonema, Calothrix, Cylindrospermum and Desmonostoc species. The toxin compounds (i.e., microcystins, nodularin, anatoxins, ambiguines, fischerindoles and welwitindolinones) and metabolites are about to have a destructive effect on both inland and aquatic environment aspects. The present review gives an overview of the various toxins that are extracted by the order Nostocales. The current research suggests that these compounds that are produced by cyanobacterial species have promising future considerations as potentially harmful algae and as promising leads for drug discovery.

Nanoparticles (NPs) are a group of particles with at least one dimension ranging from 1 nm to 100 nm in diameter and a surrounding interfacial layer. The NP-protein interactions include covalent and non-covalent bonds. Several dehydrogenase enzymes (e.g., alcohol dehydrogenase, lactate dehydrogenase, alanine dehydrogenase, glutamate dehydrogenase, leucine dehydrogenase, phenylalanine dehydrogenase, and malate dehydrogenase) are used for immobilization by NPs. Also, magnetic NPs and quantum dots are promising model systems for the design of bioanalytical sensors and biological enzyme assemblies. In this overview, we aimed to improve the current knowledge of interactions between dehydrogenase enzymes and NPs and to introduce dehydrogenases with industrial and medical applications. Also, bioconjugation of NPs with dehydrogenase enzymes has broad applications in biocatalysis and nanomedicine in the field of drug discovery. However, studies on the characterization of NP-enzyme complexes show that the anatomy and activity of enzymes are dependent on the chemistry of NP ligands, NP size, and labeling methods. Moreover, the NPprotein conjugates show increased/decreased enzymatic activities, depending on the NP features.In this study, we reviewed the findings related to NP-enzyme interactions for nanotechnology applications and conjugation techniques. We also highlighted several challenges associated with the NP-enzyme interactions, including the stability and reusability of enzymes in NP-enzyme formation.

Pseudomonas aeruginosa is one of the most common reasons for nosocomial infections. Given the high morbidity and mortality, as well as the cost of management, particularly in developing countries, burn injuries are considered important health concerns. Owing to the increased rate of resistance against antibiotics, this study aimed to isolate Pseudomonas aeruginosa strains from burn patient's wounds by analyzing antibiotic susceptibility and genetic profiling. In this regard, we explored the relationship between the nucleotide sequence and antibiotic susceptibility. In this cross-sectional study, 107 isolates of P. aeruginosa were collected from a major burn center in Tehran, Iran. The isolates were characterized with standard biochemical tests and examined by applying the Disk Diffusion method to find the patterns of sensitivity, and their genetic relationship was revealed by RAPD-PCR method. According to the antibiogram results, most of the isolates were resistant to 3 or more antibiotics tested and the most sensitivity was related to the Colistin antibiotic. RAPD-PCR method revealed a high polymorphism among P. aeruginosa isolates in Tehran. There was no significant association between the genotype groups and antibiotic susceptibility profiles. We evaluated the pattern of resistance to pathogenic organisms and identified multi-drug resistant organisms. Currently, Colistin antibiotic is the most suitable treatment option for burned patients. RAPD-PCR is a genotyping method with high efficiency for typing and categorizing different isolates of MDR-P. aeruginosa., Biotechnology; Genetics; Microbiology; Molecular Biology; Infectious disease; Pseudomonas aeruginosa; RAPD-PCR; Nosocomial infections; Burn patients.

Plant-cyanobacteria interactions occur in different ways and at many different levels, both beneficial and harmful. Plant-cyanobacteria interactions, as a beneficial symbiosis, have long been demonstrated in rice-growing areas (Poaceae) where the most efficient nitrogen-fixing cyanobacteria are present in paddies. Moreover, cyanobacteria may in turn produce and/or secrete numerous bioactive compounds that have plant growth-promoting abilities or that may make the plant more resistant to abiotic or biotic stress. In recent years, there has been a growing worldwide interest in the use of cyanobacterial biomass as biofertilizers to replace chemical fertilizers, in part to overcome increasing organic-farming demands. However, the potential presence of harmful cyanotoxins has delayed the use of such cyanobacterial biomass, which can be found in large quantities in freshwater ecosystems around the world. In this review, we describe the existing evidence for the positive benefit of plant-cyanobacteria interactions and discuss the use of cyanobacterial biomass as biofertilizers and its growing worldwide interest. Although mass cyanobacterial blooms and scums are a current and emerging threat to the degradation of ecosystems and to animal and human health, they may serve as a source of numerous bioactive compounds with multiple positive effects that could be of use as an alternative to chemical fertilizers in the context of sustainable development.

Cyanobacteria are considered a promising source for new ‎pharmaceutical lead compounds and a large number of chemically diverse and ‎bioactive metabolites have been obtained from cyanobacteria. Despite of ‎several worldwide studies on prevalence of NRPSs and PKSs among the ‎cyanobacteria, none of them included Iranian cyanobacteria of Kermanshah ‎province. Therefore, the aim of this study was to amplify the NRPS and PKS ‎genes. These stains were the most frequent species of that zone. The DNA ‎sequences of the 16s rRNA region were determined and the strains were named ‎as Scytonema sp. N11, Calothrix sp. N42 and terrestrial Nostoc SP. N66). ‎Lastly, to show that the presence of these genes correlates with natural product ‎synthesis, we conducted biochemical assays to detect the presence of ‎antimicrobial effects in organic extracts. The results of these experiments ‎suggest that both NRPS and PKS genes are presence in all three strains. ‎Finally the sequences presented in this study have been deposited in GenBank ‎for getting the accession numbers (NRPS A domains) and (PKS KS domains). ‎According to these results, it is concluded that the antibiogram bioassay and ‎molecular detection of peptide synthetase and polyketide synthase genes in ‎cyanobacterial strains may be useful techniques for the assessment of natural ‎product -producing species and possible role of peptide synthetase and ‎polyketide synthase enzyme complexes in the biosynthesis of biologically ‎active compounds.‎

Se realizó la caracterización de ficoeritrina de la cepa A5 de Nostoc sp., seguida de investigación de su actividad biológica para aplicaciones biotecnológicas. Para la extracción de ficoeritrina, el uso de tampón acetato (pH 5.1) produjo 65.04 µg mL-1, y se identificó como C-ficoeritrina. Los resultados de su actividad antioxidante sugirieron su acción como un potente eliminador de radicales libres. Además, la C-ficoeritrina de Nostoc mostró una capacidad notable como agente antibacteriano y antifúngico, con estabilidad significativa de hasta 10 días. La glucosa (4 mg mL-1) fue un buen conservante para la C-ficoeritrina a 25 y 4 ºC. Se obtuvo por primera vez una C-ficoeritrina estable de Nostoc sp. en condiciones de sequía en piedra caliza, lo que demuestra la necesidad de estudiar microorganismos de ambientes extremos. The phycoerythrin characterization from Nostoc sp. strain A5 was done, followed by investigation of its biological activity for biotechnological applications. For phycoerythrin extraction, the use of acetate buffer (pH 5.1) resulted in 65.04 µg mL-1, and C-phycoerythrin was identified. Results of its antioxidant activity suggested action as a potent free radical scavenger. In addition, Nostoc's C-phycoerythrin showed noteworthy ability for antibacterial and antifungal agents with significant stability up to 10 days. Glucose (4 mg mL-1) was a good preservative for C-phycoerythrin at 25 and 4 ºC. A stable C-phycoerythrin from Nostoc sp. was obtained for the first time from limestone drought conditions, showing the need of studying microorganisms from extreme environments.

Cyanobacteria, an abundant source of natural products as biomedical compounds have emerged as a novel resource for the progression of synthetic analogs. Due to the rise of antibiotic resistance, there is a need for new medications and cyanobacteria-derived compounds with promising antimicrobial, immunosuppressant, anti-carcinoma, antiviral and protease inhibition activity are a potent option for new therapeutics. Current research is focused on the exploitation of cyanobacteria for the production of bioactive metabolites. Screening of cyanobacteria for pharmaceutically active compounds has received increasing attention; overall, there is a promising outlook that cyanobacterial secondary metabolites will become alternatives for the development of new and more effective medications.

Background Cyanobacteria have a worldwide distribution in the terrestrial habitats, occurring predominantly on the surface of the soils, stones, rocks, and trees, practically in moist, neutral or alkaline aeries. The unique natural and bioactive compounds from cyanobacteria with various biological activities and an extensive range of chemical classes have a significant capability for expansion of the pharmaceuticals and other biomedical purposes. Objectives Regardless of the progresses in our knowledge on cyanobacteria, however, cyanobacteria are still viewed as an unexplored source of potential drugs. In this study presence of bioactive compounds among the cyanobacteria culture collection of Iran, where a wide variety of strains can be found, was investigated. Material and Methods We explored one Nostoc strain isolated from rice fields in Golestan province of northern Iran for searching for novel products. The chemical construction of the new bioactive compound was clarified by application of liquid chromatography-mass spectrometer (LC-MS) and Marfey’s analysis of the degradation products. Results We found a novel peptide aldehyde compound from a hydrophilic extract of the Nostoc sp. Bahar_M, which is composed of the three subunits, 2-hydroxy-4-(4-hydroxyphenyl) butanoic acid (Hhpba), L-Ile, and L-argininal. According to the structural information, we predicted that the novel peptide-aldehyde compound probably to be trypsin inhibitors. Conclusions Results demonstrated that terrestrial cyanobacteria are a promissing resource of bioactive natural products.

Pseudomonas aeruginosa is one of the most common reasons for nosocomial infections. Given the high morbidity and mortality, as well as the cost of management, particularly in developing countries, burn injuries are considered important health concerns. Owing to the increased rate of resistance against antibiotics, this study aimed to isolate Pseudomonas aeruginosa strains from burn patient's wounds by analyzing antibiotic susceptibility and genetic profiling. In this regard, we explored the relationship between the nucleotide sequence and antibiotic susceptibility. In this cross-sectional study, 107 isolates of P. aeruginosa were collected from a major burn center in Tehran, Iran. The isolates were characterized with standard biochemical tests and examined by applying the Disk Diffusion method to find the patterns of sensitivity, and their genetic relationship was revealed by RAPD-PCR method. According to the antibiogram results, most of the isolates were resistant to 3 or more antibiotics tested and the most sensitivity was related to the Colistin antibiotic. RAPD-PCR method revealed a high polymorphism among P. aeruginosa isolates in Tehran. There was no significant association between the genotype groups and antibiotic susceptibility profiles. We evaluated the pattern of resistance to pathogenic organisms and identified multi-drug resistant organisms. Currently, Colistin antibiotic is the most suitable treatment option for burned patients. RAPD-PCR is a genotyping method with high efficiency for typing and categorizing different isolates of MDR-P. aeruginosa.

Human skin is one of the most complex body organs that functions as a physical barrier against water loss and environmental stressors that include UV radiation, reactive oxygen species, pathogens, chemicals and physical agents. Skin texture may undergo ageing, fragility of the dermal layer, thinning, laxity, enlarged pores, dryness, fine lines, and wrinkles as a result of chronic exposure to intrinsic and extrinsic destructive factors. This leads to the growing importance of the cosmetic industry. Therefore, there is a need to investigate harmless and efficient natural raw ingredients, and cyanobacteria-derived compounds have the potential to cope with this challenge. Cyanobacteria are important metabolite sources, which can be used to fight against skin-related problems. Cyanobacteria are morphologically diverse photosynthetic prokaryotes that are broadly distributed in both terrestrial and aquatic environments. Cyanobacteria have developed special mechanisms to help them endure extreme conditions therefore various secondary metabolites can be extracted from them. Mycosporine-like amino acids, polysaccharides, pigments, scytonemin, antioxidants, and carotenoids are some of the beneficial metabolites that are extracted from cyanobacteria. Diverse cyanobacteria strains are now being broadly used in skin care products for various skin conditions by acting as sunscreens, anti-wrinkling agents, moisturizer or texture-enhancing agents. In this paper, an overview of the cosmetic potentials of cyanobacteria is presented.

Background: Cyanobacteria have a worldwide distribution in the terrestrial habitats, occurring predominantly on the surface of the soils, stones, rocks, and trees, practically in moist, neutral or alkaline aeries. The unique natural and bioactive compounds from cyanobacteria with various biological activities and an extensive range of chemical classes have a significant capability for expansion of the pharmaceuticals and other biomedical purposes. Objectives: Regardless of the progresses in our knowledge on cyanobacteria, however, cyanobacteria are still viewed as an unexplored source of potential drugs. In this study presence of bioactive compounds among the cyanobacteria culture collection of Iran, where a wide variety of strains can be found, was investigated. Material and Methods: We explored one Nostoc strain isolated from rice fields in Golestan province of northern Iran for searching for novel products. The chemical construction of the new bioactive compound was clarified by application of liquid chromatography-mass spectrometer (LC-MS) and Marfey's analysis of the degradation products. Results: We found a novel peptide aldehyde compound from a hydrophilic extract of the Nostoc sp. Bahar_M, which is composed of the three subunits, 2-hydroxy-4-(4-hydroxyphenyl) butanoic acid (Hhpba), L-Ile, and L-argininal. According to the structural information, we predicted that the novel peptide-aldehyde compound probably to be trypsin inhibitors. Conclusions: Results demonstrated that terrestrial cyanobacteria are a promissing resource of bioactive natural products.

Several risk factors have been linked to lung cancer (LC). Nevertheless, a viral etiology has been mentioned for a subset of patients developing LC. The aim of this study was to evaluate the effect of Merkel cell polyomavirus (MCPyV) on developing non-small cell lung cancer (NSCLCs). In total, 96 paraffin-embedded NSCLC biopsies and 96 adjacent non-LC normal specimens were analyzed by quantitative real-time polymerase chain reaction (PCR) for the existence of the MCPyV DNA and the expressions of RNA transcripts. Among the 96 enrolled participants, 42 patients were adenocarcinomas (ADs) and 54 patients were squamous cell carcinoma (SCC). Of the 42 ADs, MCPyV DNA was determined in 15 (35.7%) samples and of the 54 SCC, MCPyV DNA was detected in 22 (40.7%) samples. Only one non-cancerous sample in SCC subjects was positive for MCPyV LT -Ag DNA load (0.216 × 10 −3 ). In MCPyV-positive subjects, the median MCPyV copy number was higher in the patients with ADs (0.016 × 10 −3 copies/cell) compared to SCCs (0.005 × 10 −3 copies/cell); but this difference was not statistically significant ( P = 0.913). In the seven stages of LC, the MCPyV LT -Ag was quantified in stage IV (0.204 × 10 −3 copies/cell) more than in other stages. There was statistically significant difference between stages of cancer and MCPyV LT -Ag DNA load ( P = 0.002). These results revealed for the first time the presence of MCPyV in a subset of patients with NSCLCs in Iran. Further studies should be carried out to clarify the role of MCPyV in lung carcinogenesis.

Two new trypsin inhibitors, nostosin A (1) and B (2), were isolated from a hydrophilic extract of Nostoc sp. strain FSN, which was collected from a paddy field in the Golestan Province of Iran. Nostosins A (1) and B (2) are composed of three subunits, 2-hydroxy-4-(4-hydroxyphenyl)butanoic acid (Hhpba), L-Ile, and L-argininal (1) or argininol (2). Nostosins A (1) and B (2) exhibited IC50 values of 0.35 and 55 μM against porcine trypsin, respectively, suggesting that the argininal aldehyde group plays a crucial role in the efficient inhibition of trypsin. Molecular docking of nostosin A (1) (449 Da), leupeptin (426 Da, IC50 0.5 μM), and spumigin E (610 Da, IC500.1 μM) with trypsin suggested prominent binding similarity between nostosin A (1) and leupeptin but only partial binding similarity with spumigin E. The number of hydrogen bonds between ligands and trypsin increased according to the length and size of the ligand molecule, and the docking affinity values followed the measured IC50 values. Nostosin A (1) is the first highly potent three-subunit trypsin inhibitor with potency comparable to the known commercial trypsin inhibitor leupeptin. These findings expand the known diversity of short-chain linear peptide protease inhibitors produced by cyanobacteria.

An investigation was undertaken on two Nostoc strains isolated from the paddy fi elds of Iran and having different morphologies of polysaccharide sheaths. Ex tracellular polysaccharides (EPS) presumably play a major (protective) role in cyanobacteria but there are no clear reports that link EPS production with (selected) abiotic stresses. The aim here is to investigate key factors enhancing EPS biosynthesis. The relationship between cell growth and the amount of EPS were compared under photoautotrophic, mixotrophic and heterotrophic growth conditions as well as under different salt concentrations, and under nitrogen-deplete and nitrogen-replete conditions Cell growth and EPS production are both highly dependent on culture conditions, but there is no correlation between cell growth and EPS production in cultures grown in different sources of nitrogen. In contrast, light inten si ty and cel l growth in cultures experiencing mixotrophic conditions at either 150 or 50 μmol photon m–2 s–1 have strong positive effect on EPS production. In salt-rich cult ures, in the ASN_S strain the outer cell layers p rotect the inner cells from NaCl s tress and hence its growth is maintained without inhibition under the NaCl stress. Each strain of Nostoc exhibits a different pattern of EPS synthesis, making it essential that the optimal culture conditions are determined for each species reading to the development of an effi cient technology for the maximum production of cyanobacterial EPS.

tion patterns showed that while there were three different peptidic compound classes (anabaenopeptin, cryptophycin, and nostocyclopeptides), there were no signs of the presence of anatoxin-a, homoanatoxin-a, hassallidin or microcystins. Moreover, a remarkable antifungal activity was identified in the methanolic extracts. Based on the results, this study suggests that three diverse groups of potentially bioactive compounds might account for the death of these animals. This case is the first documented incident of toxicity from aquatic cyanobacteria related intoxication in dogs, mice, and aquatic organisms in Iran.