Volume 6, Issue 1 (1-2004)
Abstract
Expression analysis was carried out to characterise the level and time of expression of two senescence related cDNAs, LSC650 and LSC54, in Brassica napus and Arabidopsis thaliana. The extent of DNA sequence similarity showed that the LSC650 gene may en-code the catalase homologous to Cat3 in Arabidopsis thaliana the role of which is to scav-enge H2O2. Also, LSC54 gene encodes a metallothionein protein that may detoxify metal ions in plant cells. Plant leaves were characterised at different developmental stages by biochemical analysis, including chlorophyll and protein assays. Northern analysis re-vealed strong levels of LSC650 and LSC54 expression in senescent leaves and lower levels in mature green leaves, but very weak or no expression in young leaves in B. napus. The transcription of genes, LSC650 and LSC54, was almost at the same level with few changes between maturity and senescence in leaves of Arabidopsis at different plant growth phases, being due to a possible unknown stress. The results indicate that both genes stud-ied may act as antioxidants, and have a role in scavenging active oxygen species (AOS) caused by catabolism of macromolecules during senescence.
Zohreh Soltani, Mehran Loghmani, Mohammad Mansour Toutouni, Mohmood Sinaei,
Volume 9, Issue 4 (11-2020)
Abstract
The aim of this study was to compare the accumulation of heavy metals copper, zinc and cadmium and to investigate the changes of metallothionein as a biomarker of contamination in the gill tissue of the ghost crab Ocypode saratan in the two time periods before Monsoon (May) and after Monsoon (November) in mongrove forests. Chabahar and Gwater Bay was done in 2019. The results of the study showed that in both pre-Monsoon and post-Monsoon seasons the pattern of metal accumulation in the gill tissue of the ghost crab is zinc, copper, cadmium.The mean concentrations of copper, zinc and cadmium were obtained in the pre-monsoon and post-monsoon seasons at Chabahar station, 173.6 ± 3.83, 186.43 ± 3.1, 0.095 ± 0.008, respectively and 156.7±4.15 ،175.13 ± 2.8, 0.026 ±0.003 and in Gwater station the average concentrations of copper, zinc, cadmium in the two pre-Monsoon and post-Monsoon seasons were respectively 237.03 ± 6.4, 231.8 ± 1.8, 0.048 ± 0.003 and 205.9 ± 6.34, 253.2 ± 2.13, 0.037 ± 0.015 μg/g dry weight. The mean levels of metallothionein in pre-monsoon and post-monsoon season in Chabahar station were 2.02 ± 0.01 and 0.1 ± 0.06, respectively, and in goiter station were 2 ± 0.02 and 0.12 ± 0.02, respectively. Comparison of metallothionein levels between Chabahar and Gwater stations was not significant (P<0.05). But in both stations separately between the two pre-Monsoon and post-Monsoon seasons, there was a significant difference (P<0.05). Correlation between metallothionein and metals showed that there was no correlation between metallothionein and the studied metals. Therefore, according to the observations, changes in the concentration of metallothionein in this species are not affected by heavy metals and can be due to changes in the environmental conditions of the seasons.