Isolation and genetic identification of Cylindrotheca closterium algae from Alexandria coastal region | ||||
| Delta Journal of Science | ||||
| Article 7, Volume 41, Issue 1, June 2019, Page 66-78 PDF (5.23 MB) | ||||
| Document Type: Research and Reference | ||||
| DOI: 10.21608/djs.2020.139230 | ||||
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| Authors | ||||
| Rasha Ramadan1; Hanan Khairy2; Mohammed Halawa3; Ashraf Haider* 1 | ||||
| 1Botany Department, Faculty of Science, University of Tanta. | ||||
| 2National Institute of Oceanography and Fishery, Alexandria | ||||
| 3Botany Department, Faculty of Science, University of Tanta | ||||
| Abstract | ||||
| Text Cylindrotheca closterium alga belongs to family Bacillariaceae, order Bacillariales, class Bacillariophyceae and phylum Bacillariophyta. In this study Cylindrotheca closterium alga was isolated from Alexandria coastal region (Eastern Harbor) using two methods: dilution method and streak and spray plating technique. Isolated algal cells were cultured on Guillard F2 liquid medium. Morphological identification was carried out by light microscope and scanning electric microscope. Algal cells were found to be wrapped by the raphe canal of valves, which is a typical characteristic of Cylindrotheca closterium shape. The cells contained two plastids lying next to each other along the longitudinal axis of the cell and apprised to one side of the cell with lobes extending onto the other sides, and the nucleus centrally in between. However, previous studies indicated some morphological variations during the life cycle of the alga.Genetic identification of Cylindrotheca closterium was carried out using ribulose-bisphosphate carboxylase gene (rbcL) located in the plastids as molecular marker. Specific PCR primers were used to amplify rbcL gene fragment from total genomic DNA extracted from Cylindrotheca closterium cells. Amplified rbcL (1177 bp) gene fragment was purified and sequenced. Nucleotide sequence was compared with Cylindrotheca sequences available in the GenBank. The Genetic distances and multi alignments were computed by Pairwise Distance method using Clusteral W software analysis. The nucleotide sequence of amplified rbcL gene showed varied identity percentages (81, 80 and 78%) with other related sequences in the GenBank. This could be correlated to the observed morphological variations. Previous studies indicated high sequence divergences of rbcL gene among Cylindrotheca isolates, and numerous nucleotide variations of rbcL gene caused relatively few variation of deduced amino acid sequence. These results may indicate that Cylindrotheca closterium is a species complex as was previously evidenced by the variations of rbcL gene. | ||||
| Keywords | ||||
| Te Cylindrotheca closterium; diatoms; Bacillariophyta; rbcL gene | ||||
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