Modares Journal of Biotechnology

Abstract With the wide spread of electromagnetic waves in living environment, concerns about the harmful effects of these waves on human health have increased. However, many studies have been conducted on the biological effects of non-ionizing radiation, but there is no certainty about the effects of these radiation, especially on the nervous system. The achieved results from studies have many differences and even conflicting results have been reported. According to the previous studies, it is not yet concluded whether non-ionizing electromagnetic radiation damaging to the nervous system. The purpose of this study is to analyze published articles about the effects of non-ionizing electromagnetic radiation on the nervous system in order to extract quantitative data on the effects of these waves. The purpose of this study is to analyze published articles about the effects of non-ionizing electromagnetic radiation on the nervous system in order to extract quantitative data on the effects of these waves. At first, the articles published in the ORSAA database were reviewed and divided into two categories: cellular and molecular parameters and neurological and cognitive parameters. The results obtained from the reviews and quantitative analyzes of the articles in the ORSAA database showed that in the category of cellular and molecular parameters, non-ionizing electromagnetic waves have the greatest effect on the change of enzyme activity and damage to proteins with 418 cases. Also, in the category of neurological and cognitive parameters, non-ionizing waves have the greatest effect on behavior and cognitive effects with 171 reported cases.

Abstract Occurrence of various types of incidents such as road accidents, damage and injuries during sports activities as well as some diseases can lead to the destruction and resorption of osteochondral tissue and cause many problems in health and quality of life of the patient, therefore control and repairing these defects is one of the major challenges in the field of regenerative medicine. Since osteochondral defects involve damage to both articular cartilage and underlying subchondral bone, the demands of bone, cartilage, and bone cartilage interface should be taken into account for repair. Current clinical therapies are more palliative and less therapeutic. Hence, due to the limitations of existing treatment methods over the past decade, the use of tissue engineering as an effective and low-risk treatment method for the treatment of many diseases, especially bone-cartilage lesions has been introduced. In this approach, some of the limitations of previous methods could be overcome by transplanting osteochondral composite tissues, which have been obtained by combining patient's own cells with three-dimensional porous biomaterials of predetermined shape and size. So far, various strategies for scaffold fabrication have been used to repair osteochondral defects, including single-phase, multilayer, and graded structures. In this study, some common strategies in tissue engineering as well as the challenges ahead are briefly discussed.

Abstract
Chitinases are essential enzymes in crustaceans that play an important role in the molting cycle and digestion of chitin. Based on the present study, the chitinase encoding cDNA of Penaeus mergueinsis with a length of 1440 bp containing 467 amino acids was sequenced by PCR and then its phylogenetic and bioinformatics analysis was performed. The new sequence was registered in the gene bank with the accessition number MT250539 and the molecular weight of the protein resulting from this sequence was predicted to be 51.84 KDa and the theoretical isoelectric point of 4.79. Comparison of amino acid sequences among penaeid chitinases showed the highest identification (about 97 to 92%) with P. mondon chi-3, F. chinensis, P. vannamei and P. japonicus chi-3, respectively. Phylogenetic studies showed that chitinase in the present study belongs to group 3 chitinases. Revealed protein pattern analyzes showed that chitinase from P. mergueinsis contained the catalytic domain Glyco-18 at position 2-347, a chitin-binding site of pritrophin A at position 403-456, a disulfide bridge formed by two cysteines at position 436-421 is a chitin-binding domain type 2, active site (¹¹7FDGLDMDWE¹²⁵), a proline / threonine-rich region at positions 376-412, and a putative N-glycosylation site at position 427-424 (NTSG). The present study shows that the P. mergueinsis sequence contains active chitinase motifs similar to previously sequenced chitinases, and in the case of cloning, expression and purification probably has functional and structural features similar to the enzymes of the above species.

Abstract Spermatogonial stem cells (SSCs) are unique with an important role in the transmission of genetic information to the next generation. Thus, they play an important role for the production of interspecies germ line chimeras. Therefore, the objective of this study was to produce chimera through the intraperitoneal transplantation of Caspian brown trout SSCs into newly-hatched rainbow trout. Spermatogonial cell were isolated from the testes of 8-month-old Caspian brown trout through enzymatic digestion. The spermatogonial cell suspension was enriched using differential plating technique to remove testicular somatic cells. After culturing for 48 h in L15 supplemented with 10% serum, suspended cells were collected and stained with the fluorescent membrane dye PKH26. The stained cells were intraperitoneally transplanted into triploid rainbow trout hatchlings. At 15 and 30 days after transplantation, the recipients were investigated under a fluorescent microscope. The gonads of recipients were dissected for molecular analysis at 180 days after transplantation. Transplanted spermatogonial cells migrated toward and incorporated into recipient genital ridges. The presence of the Caspian brown trout genetic material was confirmed by PCR in 41.4% of the rainbow trout testes. These results demonstrated for the first time that the interspecies spermatogonial transplantation was successful in rainbow trout and that the somatic microenvironment of the rainbow trout gonad can support the colonization and survival of intraperitoneally transplanted cells derived from a fish species belonging to a different genus. Therefore, the SSCs transplantation can be used as a tool for conservation of Caspian brown trout genetic resources.

Abstract Total-Internal-Reflection Fluorescence Microscopy (TIRFM) is a useful tool to visualize and record the phenomena that happens below 100 nm thickness of the sample surface. This unique property of TIRFM help to perform a "qualitative" study of cytoskeleton near the cell-substrate contact. Here, distribution of actin filaments at cell-substrate interface was imaged by a TIRFM set up. Then, staining the actins cytoskeleton of the human melanoma cell and implementing the prism-based total-internal-reflection fluorescence microscope. A method to "quantify" distribution of fluorophores at cell-substrate contact is proposed.