ULTRASTRUCTURAL CHANGES OF NOSTOC OF PELTIGERA CANINA IN PRESENCE OF SO2

Sharma, Pawan Kumar; Bergman, Birgitta; Hällbom, Lars; Hofsten, Angelica V.

doi:10.1111/j.1469-8137.1982.tb03416.x

Cited by 15 publications

(9 citation statements)

References 29 publications

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“…The akinete resembles that of Nostoc isolated from cycads (Grilli Caiola & Vecchi, 1980;Sutherland, Herdman & Stewart, 1979). Stress factors, such as lack of nutrients (Sutherland et al, 1979) or air pollution (Sharma et al, 1982), have been suggested as leading to akinete-formation. It would seem that in general, symbiotic cyanobacteria are rarely exposed to stress and therefore develop few akinetes.…”

Section: Discussionmentioning

confidence: 99%

THE CYANOBACTERIUM‐ZAMIA SYMBIOSIS: AN ULTRASTRUCTURAL STUDY

et al. 1985

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SUMMARYFilamentous cyanobacteria are found intercellularly in a zone between inner and outer cortex of coralloid roots, growing below the soil surface, from the cycad Zamia skinneri Warsc. The zone is transversed by elongated Zamia cells interconnecting the two cortex layers. These host cells show characteristics of transfer cells, i.e. considerably expanded cell walls, numerous mitochondria and amyloplasts. An involvement of these cells in the transfer of solutes between cyanobacterium and host is therefore suggested. The cyanobacterium belongs to the genus Nostoc and consists of vegetative cells, heterocysts and a few akinetes. Healthy vegetative cells contain thylakoids with phycobilisomes, carboxysomes, cyanophycin and glycogen granules. Thus, no distinct subcellular modifications due to a symbiotic mode of life in the absence of light were observed.

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Section: Discussionmentioning

confidence: 99%

THE CYANOBACTERIUM‐ZAMIA SYMBIOSIS: AN ULTRASTRUCTURAL STUDY

et al. 1985

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“…Glyoxylate is known to stimulate the nitrogenase activity (3,4,28) Sodium glyoxylate was treated and used as given in (3). Transmission electron microscopy of the cyanobacterium was as described in Sharma et al (26). Extracellular polysaccharides were stained using 0.2% ruthenium red in 0s04.…”

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confidence: 99%

Glyoxylate Induced Changes in the Carbon and Nitrogen Metabolism of the Cyanobacterium Anabaena cylindrica

Bergman¹

1986

Plant Physiol.

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ABSTRAC1Addition of millimolar concentrations of glyoxylate to nitrogen-fixing cultures of Anabaena cylindnica, grown aerobically in the light, caused the following effects: an increase in the number of glycogen granules and in the excretion of carbohydrates; a decreased phycocyanin concentration, but an increase in the chlorophyll a to phycocyanin ratio. Also, an enhancement in the carbon to nitrogen ratio was noted, but this was restored if N-4+ was added simultaneously. The most pronounced effect of glyoxylate addition was a 20-fold increase in the glycine pool. The effect of glyoxylate on N2 fixation (acetylene reduction) was enhanced at high light intensities, but it did not affect the in vitro ribulose-1,5-bisphosphate carboxylase activity. However, addition of milimolar concentrations of glycolate did not cause changes in nitrogenase activity, CO2 fixation, and NH3 release comparable to those caused by glyoxylate. The primary mechanism of action of glyoxylate appears to be within the glycolate pathway of the vegetative cells and metabolically downstream from glycolate.

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“…In a study by electron microscopy, Sharma et al (1982) observed a decrease in the number of carboxysomes, an increase of cyanophysin granules and an initiation of akinete formation in the blue-green Nostoc phycobiont of Peltigera canina exposed to very high concentrations (10, 100 and 1000 ppm) of SOg. In Finland, ultrastructural changes have earlier been described in Bryoria capillaris and Hypogymnia physodes growing or transplanted in industrial environments (Holopainen, 1983(Holopainen, , 1984.…”

Section: Introductionmentioning

confidence: 99%

Injuries to Lichen Ultrastructure Caused by Sulphur Dioxide Fumigations

Holopainen¹,

Kärenlampi²

1984

New Phytologist

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SUMMARYEffects of SO2 (0'05, O'l, 0-3 and 1-0 ppm) fumigations on the ultrastructure of the lichens Bryoria capillaris (Ach.) Brodo & D. Hawksw. and Hypogymnia physodes (L.) Nyl. were studied with a transmission electron microscope. All concentrations of SOg caused characteristic ultrastructural symptoms. These were always ohservable before light microscopic and visible changes in thalli.Sulphur dioxide injury in the Trebouxia phycobiont cells of both species began as swelling and deformation of mitochondria, stretching of the chloroplast envelope and deformation of pyrenoglobuli. Later, stretching of thylakoids and degeneration of pyrenoid, chloroplast stroma, nucleus, mitochondria and cytoplasm were observable. It was typical of the later stages of SOg injury that thylakoids remained visible for a long time. The degree of injury in the algal cells increased with increasing SOj concentration and duration of exposure. The fungal cells showed ultrastructural symptoms, swelling of mitochondria and vesiculation of the mesosome-like organelle, only at the highest concentration (1-0 ppm) of SO2. The experimental results are consistent with many earlier observations on natural material collected from industrial environments. Relationships between the ultrastructural and physiological changes caused by SOg are discussed.

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ULTRASTRUCTURAL CHANGES OF NOSTOC OF PELTIGERA CANINA IN PRESENCE OF SO₂

Cited by 15 publications

References 29 publications

THE CYANOBACTERIUM‐ZAMIA SYMBIOSIS: AN ULTRASTRUCTURAL STUDY

THE CYANOBACTERIUM‐ZAMIA SYMBIOSIS: AN ULTRASTRUCTURAL STUDY

Glyoxylate Induced Changes in the Carbon and Nitrogen Metabolism of the Cyanobacterium Anabaena cylindrica

Injuries to Lichen Ultrastructure Caused by Sulphur Dioxide Fumigations

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