An Ultrastructural and Cytochemical Study on Conjugatophycean Cell Wall

Abstract

SUMMARY -A cytochemical study was carried out to investigate the composition of the extracellular matrices in different species of unicellular and filamentous Conjugatophyceae. The study allowed us to determine the distribution and the precise localization, at the ultrastructural level, of different groups of chemical components. There were clear differences between unicellular and filamentous species, as regards the kind of cell wall texture, the structure and architecture of the external mucilaginous sheath, and the distribution and localization of chemical components within it. The same cytochemical techniques were used to investigate the behavior of extracellular envelopes during the conjugation process only in Spirogyra. These layers underwent extensive modifications during conjugation: the mucilaginous sheath disappeared and glycoproteinaceous material was accumulated in the cell wall of the forming conjugation papilla.

Possible surface carbohydrates involved in signaling during conjugation process in Zygnema cruciatum monitored with fluorescein isothiocyanate‐lectins (Zygnemataceae, Chlorophyta)

“…However, our results show that the composition of surface carbohydrates on conjugation papilla is different from that of external mucilage and some new glycoconjugates were produced and secreted from the tip of protruding papilla, indicating that the external mucilage is not directly involved in the signaling or cell-cell recognition during the conjugation process. This suggestion is supported by an ultrastructural study by Cheli and De Vecchi (1989), which showed that the extracellular mucilaginous sheath disappeared, and a glycoproteinaceous material was accumulated in the cell wall of the developing papillae during conjugation.…”

“…In an elaborate ultrastructural study, Cheli and De Vecchi (1989) showed that the extracellular mucilage of Spirogyra filaments disappeared during conjugation and some glycoproteinaceous materials were accumulated in the cell wall of the developing conjugation papilla, suggesting that the chemical composition in the cell surface changed during the process. Surface carbohydrates on some vegetative cells and differentiating rhizoid cells were observed in several species of Zygnema and Spirogyra by the use of fluorescein isothiocyanate (FITC)-lectins (Sengbusch et al 1982;Inoue et al 1999), but there is no analytical study on surface carbohydrates during conjugation in the zygnematacean species.…”

Studies on conjugation of Spirogyra using monoclonal culture

“…Presence of the extracellular glyco-proteinaceous materials in the cell wall of conjugation tube of Spirogyra sp. have been reported (Cheli and De Vecchi 1989 ). In order to identify the extracellular material, we examined staining with fluorescently labeled lectins.…”

Morphology of Cell Wall Pore Channels in the Genus Euastrum Ralfs (Desmidiales)

“…У представителей семейства Desmidiaceae в процессе деления первичная целлюлозная клеточная стенка сбрасывается сразу после формирования вторичной, пронизанной поровыми каналами [4]. К настоящему времени накоплен большой массив данных относительно строения и морфогенеза клеточной стенки и порового аппарата в семействе Desmidiaceae, однако исследования проводили только на нескольких представителях родов: одноклеточных -Micrasterias [1,5], Cosmarium [6,7], Pleurotaenium [3], Oocardium [8], Staurastrum [9], и нитчатых колониальных -Bambusina, Desmidium, Hyalotheca, Spondylosium, Sphaerozosma [10].…”