amir abbas mokhtarieh

Laccases are a group of glycoproteins which can oxidize a wide range of compounds with various biological activities and industrial applications in food and beverage, pharmaceutical, textile, and even military-related industries. Regarding this enzyme structure and the ability of plant protein production machinery for protein glycosylation, a construct consisting of fungal laccaseII under control of root-specific mannopine synthase promoter and tobacco etch virus translation enhancer was designed for tobacco transformation to be used in phytoremediation. N-terminal addition of acidic tobacco endochitinase Q to Laccase directs its apoplastic secretion. Putative laccase agrobacterium-mediated transformants were confirmed using polymerase chain reaction. Semi-quantitative PCR of roots and leaves of putative transformants showed differential expression of the laccase gene at the transcriptomic level resulting from the differential function of bacterial mannopine synthase promoter. Western blotting results confirmed production of mature protein in roots which also confirms the correct function of signal peptide and secretion of this enzyme into the apoplastic space of roots. Regarding their application for protein production or phytoremediation transgenics of interest should be screened based on protein concentration and enzyme activity.

Laccase is a polyphenol oxidase, highly glycosylated that mainly presents as monomeric proteins with varying mass of 50-90 kDa. This enzyme oxidizes lignin using molecular oxygen which produces water as the only by-product but it shows specificity to broad range of substrates such as phenols including ortho- and para-diphenols, amino phenols, methoxy phenols, polyphenols, polyamines, aryl diamines and ascorbate. Laccase can be found in fungi, plants, insects and bacteria. Laccases are involved in a wide range of biological functions including pigment formation in fungi, ectomycorrhizal symbiosis, metabolism of proanthocyanidins, virulence of pathogen fungi and sexual development. Regarding its unique function it is getting more attention for novel applications in biosensors, microfuel and bioelectrocatalysis. In addition, it is used in food, pharmaceutical and cosmetic, pulp and paper and textile industries. It has especial potential to be used in bioremediation to remove water and soil pollutions resulted from different industries. This has made researchers to produce transgenic plants containing heterologous laccases to be able phytoremediate polluted soil and water resources with chemicals including different organophosphorus pesticides and nerve agents. Additionally, hydroponic culture of these transgenic plants can be considered as an inexpensive approach for commercial production of laccase exploiting rhizosecretion strategy.

Stem cells are valuable for cell therapy. One of the important disadvantages of stem cells for cell therapy is stem cell senescence. Based on the reports, cell division causes telomere attrition and shortening which this in turn leads to cell senescence. Telomeres are short sequences at the both end of chromosomes that hinder chromo- somal attachment. Since pluripotency of stem cells reduces by each cell division, one can conclude that the telomere shortening of stem cell by passaging is inevita- ble. Here we decided to evaluate the relation between the telomere length and cell passages in human adipocyte stem cells (hAdSCs) by qPCR and Southern blotting. For this purpose, first the AdSCs were isolated from adipocyte tissue by collage- nase digestion. Then isolated hAdSCs were subjected to flow cytometry to purify hAdSCs from the rest of adipocyte cells by means of expression of surface markers such as CD105, CD90, CD73 and CD43. Purified hAdSCs were subcultured till appropriate passages (passage 2 and 17). Genomic DNA of appropriate passages were extracted and subjected to both qPCR and Southern blotting for telomere length measurement. Based on the results, hAdSCs telomere length in the passage 2 was much longer than passage 17. Moreover, the longer telomere length in passage 17 was confirmed by Southern blot. Our results indicated that telomeres attrition occur in hAdSCs by each cell division.