مجله پژوهش های سلولی مولکولی (زیست شناسی ایران)
سال سی و ششم شماره 4 (زمستان 1402)

In the present study, the effect of sodium nitroprusside and silicon on the organogenesis of cotyledonary thin cell layer explants of tomato of tomato (Lycopersicon esculentum Mill.) was studied. This research was conducted in three independent experiments. In the first experiment, cotyledon explants and thin cell layers with 1 mm transverse sections of 8 and 12 days old cotyledons were cultured in MS medium supplemented with 2 mg/L BAP and 2 0.0 mg/L of IAA. Obviously almost all 8-day-old explants regenerated shoots but 12-day-old explants get the necrosis without any organogenesis. After determining the best age of the explant, in the second experiment the effect of BAP alone and in combination with NAA and IAA was evaluated in improving the organogenesis of tomato using both explants. The results showed that almost all Plant regulator combination had more than 90% organogenesis. In the analysis of the number of shoots, the medium supplemented with 2 mg/L of BAP and 0.2 mg/L of IAA showed the highest shoots number per explant. In the third experiment adding 10, 15 and 30 μM of sodium nitroprusside, significantly increased the shoot induction frequency, number of shoots per explants and root induction, respectively. The addition of 50 and 5 mg/L of silicon to the culture medium increased the number of shoots per explants, but adding 500 mg/L of silicon completely stopped the organogenesis.

Taxol is an anti-cancer drug and can be extracted from the yew tree. The aim of this study was to investigate the effects of Methyl jasmonate and Salicylic acid elicitors on taxol production in hairy roots formed in Iranian yew. Three strains of Agrobacterium rhizogenes A4, R1000 and ATCC15834 were used to create hairy roots in yew explants. The results showed that only A4 strain caused the formation of hairy roots in the explants and PCR analysis showed that the Agrobacterium rooting gene was transferred to the explants. In the operation of growing hairy roots, three concentrations of 1, 10 and 100 µmol of methyl jasmonate and salicylic acid were used separately and in combination to increase paclitaxol production. The analysis performed by HPLC showed that the addition of elicitors to the culture medium increases the amount of taxol in hairy roots, and the greatest increase was obtained by adding 100 micromoles of methyl jasmonate alone, which increased the amount of paclitaxol production in hairy roots by 5 times.

Drought stress is one of the main environmental factors affecting the growth, yield and quality of agricultural products. Unfortunately, global climate change and mismanagement have led to the expansion of the arid and semi-arid lands of the world. Meanwhile, sunflower is one of the important oilseed plants relatively resistant to drought stress. The present study was conducted to identify molecular markers associated with genomic regions controlling agro-morphological traits in sunflower under drought stress. The associated markers are potentially useful for breeding programs and can accelerate the selection of drought tolerant genotypes. 100 sunflower genotypes were planted in a 10 ×10 simple lattice design with two replications in each one of normal and irrigation limited conditions for two consecutive years. Molecular profiles of the lines were prepared with 7 IRAP primer combinations. According to mlm, 12 and 10 markers showed significant relationships with the studied traits (P≥ 0.01) under normal and irrigation limited conditions, respectively. “61655” showed a significant relationship with oil percentage under both normal and irrigation limited conditions. The markers “616510” and “61655” and “CfCr1” showed a significant relationship with several traits under normal and irrigation limited conditions, respectively, that can be due to pleiotropic effects or linkage between genes controlling traits. Accordingly, “616510” marker related with genomic regions controlling yield under normal conditions and "CfCr1" marker related with genomic regions controlling yield components traits (head and stem diameter) under irrigation limited conditions, after validation, can be used for selection of optimal genotypes under these water treatment conditions.

Cyclomaltodextrinase (CDase) is belonging to a class of enzymes that are involved in carbohydrate degradation. It is one of the most important enzymes from the amylase family with highly important industrial applications. Recently, a variant of native CDase has characterized and reported (Accession number: AMB26774). Previous study on this enzyme and three representative mutants including A123V, C127Q and their respective double mutant, A123V/C127Q has shown that applying point mutations on the interface between the subunits has functional and structural consequences. In current work, complete set of experimental study and modelling procedures was performed to elucidate the thermodynamics behavior of the enzyme variants in chemical denaturation experiments using Guanidinium chloride (GdmCl) as chemical denaturant. It was shown that the wild-type protein with the maximum value of ∆G^(H_2 O) is the most stable variant, as compared with mutants. It appears that the replacement of residues at positions 123 and 127 leads to increasing the flexibility of the protein chains and that the feasibility of the GdmCl penetration and interaction with mutants as compared with the WT protein. We concluded that these positions are hot spot points that can be more manipulated to change the structural features of the enzyme toward thermal and chemical stability.

The pathogenic E. coli O157: H7 is capable of causing a wide range of complications, such as dysentery and hemolytic uremic syndrome. Due to the difficulties in antibiotic treatment, immunization seems to be the most appropriate way to fight this bacterium. Intimin, Tir, and EspA proteins are the three major proteins involved in the binding of the bacterium to the gastrointestinal tract. By inhibiting the binding of these proteins, colonization is limited and disease is inhibited. Selecting the effective portions of these proteins and producing a recombinant chimeric protein by binding them together, researchers have developed a suitable and effective immunogen to prevent the disease. Therefore, achieving high amounts of recombinant protein, along with maintaining its quality and efficiency, is very important. In the present study, due to the increase in the quantitative and qualitative expression of some recombinant proteins under gravity removal conditions, the expression of EIT recombinant proteins under simulated microgravity conditions on a clinostat device was investigated. After optimizing the expression conditions and confirming the recombinant protein using immunological methods, its expression was induced in weightlessness simulator conditions. After purification of the protein by chromatographic column, its amount was measured by standard methods. The results showed that despite the decrease in expression under weightlessness, probably due to lack of proper aeration of the culture medium, recombinant protein was produced with appropriate quality under weightlessness. It is expected that with optimizing the conditions and using aeration methods in weightlessness, the production of recombinant proteins to significantly increases.

Regulation of flowering time requires the activity of various genes that are controlled by environmental and internal cues. The FLC gene plays a key role in transition to flowering and suppresses flowering as target gene of vernalization pathway. Vernalization is a natural adaptation to ensure flowering after winter so that flowers and seeds can develop in favorable environmental conditions. In this study, identification and expression of FLC gene was investigated in rocket mustard (Sisymbrium irio). Total RNA was extracted from cotyledon leaves and cDNA was made. Specific primers were designed based on tsequence alignment of FLC homogenous genes and used for RT-PCR reaction. The identified 449 nucleotids fragment was recorded as SiFLC with accession number KT156751 in the NCBI database. Sequencing of the coding region and comparison of its putative protein (with 150 amino acids) and FLC orthologues in other plants showed their high similarity. Expression relative rate using the semi-quantitative method, in vegetative stage in young leaves, mature leaves, stems and roots was between 56-86%, which the highest (about 86%) and the lowest (about 56%) levels were observed in young leaves and stems respectively. In the reproductive stage, a decrease in expression was observed in these organs especially in leaves (about one percent). However, expression level was higher in flower buds and reached about 31%. Decreasing leaf expression in the reproductive phase indicates flowering induction. FLC higher levels in flowers, after transition to flowering, allows the next generation to reregulate its rate and respond to winter during vegetative phase