Cyanobacteria are well known for their production of a multitude of highly toxic and / or allelopathic compounds. Among the photosynthetic microorganisms, cyanobacteria, belonging to the genus Nostoc are regarded as good candidate for producing biologically active secondary metabolites which are highly toxic to humans and other animals. Since so many reports have been published on the poisoning of different animals from drinking water contaminated with cyanobacteria toxins, it might be assumed that bioactive compounds are found only in aquatic species causes toxicity. However, the discovery of several dead dogs, mice, ducks, and fish around paddy fields, prompted us to study the toxic compounds in a strain of Nostoc which is most abundant in the paddy fields of Iran, using polymerase chain reaction and liquid chromatography coupled with a diode array detector and mass spectrophotometer. Results of molecular analysis demonstrated that the ASN_M strain contains the nosF gene. Also, the result of ion chromatograms and MS 2 fragmentation 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.Key Words: cyanobacteria; natural bioactive compound; Nostoc; toxicity INTRODUCTIONThe genus Nostoc is an ecologically, morphologically, and physiologically diverse genus of microorganisms inhabiting soils, and represents large reservoir of potentially valuable natural compounds (Dembitsky and Řezanka 2005). The ecological significance of the Nostoc species extends beyond the compounds which they primarily known to produce, as many of these organisms are capable of modifying their habitats through the synthesis of biologically active products (Ehrenreich et al. 2005). These compounds demonstrate a diverse range of biological activities and chemical structures, including novel cyclic and linear lipopeptides, fatty acids, alkaloids, and other organic chemicals (Dittmann et al. 2001). A large number of novel antimicrobial agents have been identiReceived September 16, 2012, Accepted November 20, 2012 *Corresponding Author E-mail: bahare77biol@yahoo.com Tel: +98-91-1371-0956, Fax: +98-21-8884-8940 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 304 1,500-2,000 lux for two weeks (Kaushik 1987). Three small fragments of growing co...

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Bone repair has been a new approach in regenerative medicine especially by application of stem cells. Discovering a suitable combination of scaffolds to stimulate osteogenesis is one of the major concerns in this issue. Porous polymeric scaffolds such as poly l‐lactic acid (PLLA) have been attracted a lot of attention because of their biodegradability. In the present study, we have been coated Baghdadite on the plasma‐treated surface of PLLA and evaluated osteogenic potential of mesenchymal stem cells (MSCs). Adipose tissue‐derived mesenchymal stem cells (AD‐MSCs) were cultured on PLLA and PLLA–Baghdadite scaffolds, and cell properties were characterized by MTT assay, scanning electron microscope, and FTIR analysis. Then, osteogenic differentiation potential of AD‐MSCs has been investigated, such as alkaline phosphatase (ALP) activity, calcium mineral deposition, and the expression of bone‐related genes (RUNX2, ALP, and OCN). The results have been indicated that calcium content and ALP activity of cells cultured on PLLA–Baghdadite nanofibers were higher than that of tissue culture polystyrenes (TCPs). Gene expression analysis showed that PLLA–Baghdadite had effectively induced osteogenesis‐related genes. Taken together, these results suggest that porous nanofiber scaffolds which coated with Baghdadite can enhance osteogenic differentiation of AD‐MSC, and PLLA–Baghdadite can be used as a new biodegradable scaffold for bone regeneration. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1284–1293, 2019.

Human induced pluripotent stem cells (iPSCs) have been shown to have promising potential for regenerative medicine and tissue engineering applications. Chondrogenic differentiation of iPSCs is important for application in cartilage tissue engineering. In this study, we considered the effect of nanofibre-based polyethersulfone (PES) scaffold on the chondrogenesis of iPSCs. IPSC cells were cultured on the PES scaffold and scaffold free method. After 21 d, real-time PCR was performed to evaluate the cartilage-specific genes in the mRNA levels. For confirm our results, we have done immunocytochemistry and scanning electron microscopy (SEM) imaging. According to the results, higher significant expressions of common chondrogenic-related genes such as aggrecan, collagen type II and collagen type X were observed in PES seeded human iPSCs when compared to the mRNA levels measured in scaffold free method. Expression of collagen type I down regulated in both methods. Also, both methods were showed a similar pattern of expression of SOX9. Our results showed that nanofibre-based PES scaffold enhanced the chondrogenesis of iPSCs and the highest capacity for differentiation into chondrocyte-like cells. These cells and PES scaffold were demonstrated to have great efficiency for treatment of cartilage damages and lesions.

Mesenchymal stem cells are widely stimulated by transforming growth factor beta-3 (TGFβ3) for chondrocyte differentiation. The objective of our study was to establish a new method for differentiation of human mesenchymal stem cells toward chondrocyte by overexpression of MicroRNA-140 (miR-140), and also this method was compared with method of induction with TGFβ3 in high-cell density culture systems. Mesenchymal stem cells were harvested from bone marrow of human. We prepared vectors and then was used for recombinant Lenti virus production in HEK-293 cell. Transducted cells were cultured in monolayer culture system and were harvested after days 7, 14, and 21. Real time polymerase chain reaction (RT-PCR) was performed to evaluate the cartilage-specific genes in the mRNA levels. Also, in order to confirm our results, we have done immunocytochemistry technique. Bone marrow mesenchymal stem cells (BMSCs) were transducted with recombinant Lenti virus, and miR-140 was expressed. Immunocytochemical method confirmed the differentiation of BMSC toward chondrocyte with handling cartilage matrix genes. Also real-time PCR showed that after expression of miR-140 in transducted BMSCs significantly increased gene expression of collagen type II and aggrecan and downregulated expression of collagen type I when compared with the mRNA levels measured in nontransducted BMSCs. These results were compatible compared with TGFβ3 induction method as control positive. In this study, we described a new approach and technique that may be applied for differentiation of BMSCs to chondrocyte instead of stimulation with TGFβ3. Our data implies that miR-140 is a potent chondrogenic differentiation inducer for BMSCs, and we have shown increasing chondrogenic differentiation by using miR-140 overexpression.