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Showing 3 results for Centrifugation
Volume 4, Issue 3 (12-2015)
Abstract
In this work, the paste of microalga, Tetraselmis suecica, was produced and the effects of vitamin C and E on its food value and shelf life improvement during eight weeks of storage in refrigerator (4°C) was investigated. The microalga was initially mass grown up to logarithmic phase in standard convey medium, then concentrated by cream skimmer centrifugation method. The obtained algal paste was treated by adding vitamins C, E and their mixture (all 0.1% weight/weight), and refrigerated for 8 weeks. The density of algal cells was1.38109 cells/ml and the production yield was about 1.7 gr/l. The cell viability in vitE-treated pastes (39/99±2/1%) was higher than the control group (p>0.05), indicating the positive effect of the preservatives. The proximate analysis showed that the control group had the lowest moisture (86.8 %), the vit C-treated group had the highest protein (36.6%) and lowest ash (29.9%), and the mixture of vits-treated group had the highest fat content (13.4%) at the end of the storage period. pH in the control and vit- C treated groups was lower than the other two treatments (p>0.05). In conclusion, using of vitamins E and C as well as refrigerator storage are suggested for qualitative preservation of T. suecica algal paste.
Sh. Rashidi, M.r. Abdollahi, H. Sarikhani, S.s. Moosavi,
Volume 10, Issue 2 (7-2019)
Abstract
The production of double haploid plants can be used as an effective method for plant breeding. In this research, in order to produce chickpea haploid plants, 1mm-long anthers of Bivanij cultivar containing the microspores at uni-nucleate stage were isolated from suitable buds (3mm in length) and exposed to different centrifuge (150g, 300g and 600g each for 3, 6 and 10 minutes) and electrical shock pretreatments (0, 100, 150 and 200V) in the 2ml microtubes containing 1.5ml of RM-IK medium. The treated anthers were then cultured in an EDM culture medium containing 10mg/l 2, 4-D and 10mg/l silver nitrate to induce callus and embryos. Results showed significant differences between different levels of centrifugation, different levels of electric shock and their interactions for the studied traits. The highest percentage of embryogenesis was observed in centrifuge pretreatments of 150g for 6 minutes, 300g for 3 minutes, 150g for 3 minutes in combination with 150V electrical shock, 300g for 6 and 10 minutes and combination of 150g centrifuge pretreatment for 3 minutes with electric shock of 200V, while the highest percentage of plant regeneration was obtained from centrifuge pretreatment of 300g for 6 minutes and also the combination of centrifuge pretreatment of 150g for 3 minutes with electric shock of 150V.
Volume 19, Issue 3 (11-2016)
Abstract
Objective: Cell-derived microvesicles are described as a new mechanism for cell-to-cell communication. Stem cell-derived exosomes have been described as a new mechanism for the paracrine effects of mesenchymal stem cells (MSCs). In this regard, exosomes may play a relevant role in the intercellular communication between MSCs and tumor cells.
Methods: Exosomes were purified from the conditioned medium of MSCs by differential centrifugation. Exosome size and morphology were examined by scanning electron microscope and sized with dynamic light scattering (DLS). Western blot analysis confirmed the exosomes by using CD9 as a marker. Purified exosomes were labeled with a PKH26 red fluorescent labeling kit. The labeled exosomes were incubated with SKOV3 ovarian tumor cells for 12 h at 37°C, and we used an inverted fluorescence microscope to monitor cellular uptake.
Results: Scanning electron microscopy revealed that the purified MSCs-derived exosomes had a spherical shape with a diameter of approximately 30-100 nm. Exosome size measurement by dynamic light scattering analysis also showed a single bell-shaped size distribution with a peak of ~80 nm. Western blot analysis also demonstrated the presence of CD9 (a representative marker of exosomes) in the purified exosomes. These data confirmed that the vesicles isolated from MSCs-conditioned media were the exosomes based on their size and presence of the protein marker CD9. Florescent microscopy showed that PKH26-labeled exosomes could be taken up by SKOV3 tumor cells with high efficiency.
Conclusion: Our approach for isolation, characterization and cellular uptake of exosomes derived from MSCs is valuable and a prerequisite for future studies that intend to discover exosome function in tumor cells. The ability to study the biology of exosome uptake in cancer cells could provide opportunities for functional studies of these natural nanovesicles and their contents in cancer therapy.
