Effects of cadmium and copper on the ultrastructure ofAnkistrodesmus braunii andAnabaena 7120

Abstract

The effects of brief exposure to, or growth in the presence of, lethal and sublethal concentrations of Cu(NO)2 and Cd(NO3) on the ultrastructure of the blue-green algaAnabaena 7120 and the green algaAnkistrodesmus braunii were studied. Exposure to increasing amount of both metal ions led to the appearance of larger proportions of electron-dense cells whose organelles were less well defined than those of untreated cells. Metal-treated cells ofAnabaena 7120 became distorted. Some had a corrugated appearance. Others lysed, leaving a much larger proportion of heterocysts. Such heterocysts were often empty or had a curious collapsed appearance. Growth ofA. braunii in the presence of 10(-4) M Cu(NO2)2 produced substantial numbers of multinucleate giant cells with thick walls; such cells result from repeated mitotic division without subsequent cytokinesis. The giant cells contained centrioles, structures not as yet found in normal cells of the genusAnkistrodesmus. Some nuclei of giant, but not of normal, cells contained deep indentations that appeared as "holes" in cross section. Some giant cells also contained triple parallel strands of endoplasmic reticulum which extended across much of the cell, connecting to the nuclear envelope. Some ultrastructural changes were also noted in algal cells grown over sediment containing Cu or Cd, but these were generally less severe than those occurring when metal ions were added directly to the algal cultures.

Copper resistance in Anabaena variabilis: Effects of phosphate nutrition and polyphosphate bodies

“…Microscopic examination suggested that the greater binding ability of the sensitive culture may have been due to release of intracellular substances after lysis. Such lysis was observed earlier with another Anabaena strain [26].…”

Quantitative ultrastructural changes associated with lead-coupled luxury phosphate uptake and polyphosphate utilization

“…This significant decrease with phosphate deprivation and metal exposure is consistent with the idea that metabolic processes are reduced under adverse conditions and cells may become dormant. Massalski et al (1981) reported an increase in intrathylakoid space with copper treatment. Changes in vacuole volume, presumably a result (Tables 1-9) of changes in membrane permeability (Sicko-Goad 1982), were evident in Scenedesmus.…”

Alr0397 Is an Outer Membrane Transporter for the Siderophore Schizokinen inAnabaenasp. Strain PCC 7120

“…Even though these metals are required for the function of respiratory, photosynthetic, and nitrogen-assimilating complexes, their intracellular level and thereby their uptake have to be tightly controlled, as they pose a risk for oxidative stress (50). The presence of about 1 mM iron (29) or about 10 M copper in medium (7,33) largely impairs the growth of Anabaena sp. Not only intoxication but also starvation is a danger for cyanobacteria.…”