title: Microscopic, molecular, and biochemical investigations to characterize a benthic cyanoprokaryote Leptolyngbya strain from Egypt.
abstract: Microscopic, molecular, and biochemical investigations were conducted to describe a benthic mat-forming Leptolyngbya isolate collected from wastewater canal in Helwan area, Egypt. Microscopic examination revealed that the isolate was filamentous, nonheterocystous, with obvious granular surface ornamentation. Electron microscopy was used to reveal the isolate's ultrastructure. Cross walls were thick with uneven deposition. Thylakoids were convoluted and irregularly distributed. Granular content differed from one cell to the other probably due to their physiological stages/position within the filaments and/or their age. Nycridial cells were present. Highly refractile gas vesicle-like structures were detected and their identity as gas vesicles was confirmed by amplifying the gene coding for the gas vesicle protein GvpA. The presence of gas vesicles in benthic microorganisms is intriguing, and it is possible that those vesicles serve as a floating and dispersal mechanism as they increase in filaments that are about to break and release vacuolated hormogonia. To further confirm the isolate's identity, molecular analysis using 16S rRNA gene was performed. The sequence showed only 94% similarity to Leptolyngbya badia and less than 92% to other leptolyngbya. The phylogenetic analyses showed the coclustering of this strain with other Leptolyngbya strain. The fatty acid composition, used as a chemotaxonomic marker, revealed the presence of a considerable amount of polyunsaturated acids. Nevertheless, saturated fatty acids represented the highest proportion of the total fatty. Surprisingly, fatty acids of relatively limited occurrence within oscillatorian cyanobacteria such as saturated myristic fatty acid and polyunsaturated fatty acid C16:3 were found.
authors.affiliation: Department of Botany and Microbiology, Faculty of Science, Helwan University, Ain Helwan, Helwan, Egypt. nerminel_semary@yahoo.co.uk
authors.forename: Nermin Adel
authors.initials: NA
authors.lastname: El Semary
mesh_terms: D002473:Cell Wall / Q000648:ultrastructure; D016000:Cluster Analysis; D000458:Cyanobacteria / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification*; D003593:Cytoplasm / Q000648:ultrastructure; D022162:Cytoplasmic Vesicles / Q000648:ultrastructure; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004534:Egypt; D005227:Fatty Acids / Q000032:analysis; D008853:Microscopy; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D062065:Wastewater / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D062065:Wastewater