Physiology and cytological chemistry blue-green algae.

Wölk, C. Peter

doi:10.1128/mmbr.37.1.32-101.1973

Cited by 189 publications

(71 citation statements)

References 375 publications

(574 reference statements)

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“…In the absence of combined nitrogen, however, heterocysts differentiate from vegetative cells at regularly spaced intervals along the filaments (Haselkorn, 1978; Adams and Carr, 1981). It is now known that these heterocysts function as the exclusive sites of nitrogen fixation in aerobically grown cultures (Fay et al, 1968;Wolk, 1973;Haselkorn, 1978).…”

Section: Introductionmentioning

confidence: 99%

Differences in mRNA levels in Anabaena living freely or in symbiotic association with Azolla.

Nierzwicki‐Bauer¹,

Haselkorn²

1986

The EMBO Journal

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Azolla is a small water fern in whose leaf cavities the filamentous nitrogen‐fixing cyanobacterium Anabaena azollae is symbiotically associated. Using cloned genes from Anabaena 7120 for glutamine synthetase (GS), ribulose‐1,5‐bisphosphate (RuBP) carboxylase, nitrogenase and the 32‐kd protein of photosystem II, mRNA levels of the corresponding genes in the Anabaena endosymbiont were studied by Northern hybridization. In RNA isolated from the endosymbiont there is a 10‐fold reduction of GS transcript levels, a greater than 5‐fold increase in 32‐kd transcript levels and a greater than 5‐fold decrease in RuBP carboxylase transcript levels, compared with levels in the free‐living Anabaena azollae. In the endosymbiont and in heterocysts of the free‐living Anabaena azollae the nif H, nif D, and nif K genes are transcribed from a single nif HDK operon.

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Section: Introductionmentioning

confidence: 99%

Differences in mRNA levels in Anabaena living freely or in symbiotic association with Azolla.

Nierzwicki‐Bauer¹,

Haselkorn²

1986

The EMBO Journal

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“…Both types were present in the alga grown in nitrogen-free medium but the intercalary ones were not formed during growth in ammonium medium. These intercalary heterocysts thus behave like those of simple filamentous cyanophytes in that they are suppressed in the presence of ammonium (Fay, 1973;Wolk, 1973) and it is suggested that the function of these heterocysts is to fix gaseous nitrogen.…”

Section: Discussionmentioning

confidence: 99%

“…Information about heterocyst differentiation is available mainly for simple filamentous cyanophytes (Fay, 1973 ;Wolk, 1973). In these algae, ammonium ions partially or completely inhibit heterocyst formation (Fogg.…”

Section: Introductionmentioning

confidence: 99%

The Heterocysts of the Blue‐green Alga Nostochopsis Lobatus: Effects of Cultural Conditions

Tiwari

1978

New Phytologist

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SUMMARYThe branched filaments of Nostochopsis lobatus form infrequent intercalary heterocysts in the main trichome while the short lateral branches (1-4 celled) characteristically produce only a terminal heterocyst when the alga is grown in a medium devoid of combined nitrogen. In the presence of ammonium nitrogen, intercalary heterocysts are not formed but the lateral heterocysts enlarge to assume a balloon-like appearance; they undergo division in situ and liberate 3-5-called germlings. These germlings grow and produce similar heterocysts and the cycle is repeated until growth ceases. Heterocysts are produced at the terminal ends of the long lateral branches during the later stages of growth in ammonium medium; they are not formed, in this position, in cultures grown in nitrogen-free medium. The possible role of lateral heterocysts in controlling growth and development of long laterals is discussed.

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“…Fritsch (1951) attributed the appearance of the granules to the accumulation of the building material of the cell wall. Fogg (1951) showed that the polar granules abound in material which reacts positively to stains for arginine and to the Feulgen reaction, but unlike cyanophycin granules these are insoluble in acids (see, however, Wolk, 1973). I n recent years few details of the composition of the granules have been worked out, but in the light of the physiological relationship between the heterocyst and adjacent cells it is probable that these bodies have special permeability properties.…”

Section: Structurementioning

confidence: 99%

The Heterocysts of Blue‐green Algae (Myxophyceae)

Tyagi¹

1975

Biological Reviews

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Summary 1. Heterocysts are found in many species of filamentous blue‐green algae. They are cells of slightly larger size and with a more thickened wall than the vegetative cells. 2. Structural details of the heterocyst are: the presence of three additional wall layers, the absence of granules, sparse thylakoid network throughout, except at the poles where a dense coiling of membranes occurs. Other characters include the two pores at opposite poles ‘plugged’ with refractive material called the polar granule. 3. Peculiarities in the pigment composition of the heterocyst include an abundance of carotenoids and absence of phycobilins, and a short‐wave form of chlorophyll a. 4. Unique glycolipids and an acyl lipid, not found in the vegetative cells of the algae or in other plant cells, are associated with the heterocyst. The glycolipids constitute the laminated layer of the wall and probably regulate diffusion of substances through it, whereas the acyl lipids are supposed to function as carriers and intermediates in the biosynthesis of the wall. 5. The heterocysts develop from vegetative cells, and the visible changes during differentiation include cell enlargement, synthesis of additional wall layers, disappearance of granules and reorientation and synthesis of the thylakoids. 6. Heterocysts are formed sequentially with characteristic cellular spacing during the growth of cultures in medium free from combined nitrogen. 7. Various sources of combined nitrogen inhibit heterocyst formation when supplied in the culture medium. Ammonium salts are among the most powerful inhibitors. Heterocysts are formed simultaneously and within a short period after transference of ammonia‐grown non‐heterocystous filaments to ammonia‐free medium. 8. Incompletely differentiated heterocysts or proheterocysts are found in cultures grown in the presence of combined nitrogen. If two or more proheterocysts are close together generally a single one develops to maturity after a competitive interaction in medium free from combined nitrogen. This indicates that heterocyst formation is completed in two phases: phase I, synthesis and conservation of macromolecules, which takes place during growth in ammonia‐containing medium: and phase 11, morphological differentiation of the heterocyst which is unaccompanied by growth in cell number. In the ammonia‐free medium phase 11 quickly succeeds phase 1 and the whole process appears as a continuum. 9. Heterocyst formation shows a definite requirement for light. Red light favours heterocyst formation, whereas green and blue light do not. The effects of light seem to be mainly due to photosynthesis, although some effects may be morphogenetic. 10. Studies with metabolic inhibitors have revealed the involvement of photosynthesis, respiration and protein synthesis in heterocyst formation. Photosynthesis provides carbon skeletons, whereas ATP is most probably supplied by oxidative metabolism. 11. Various functions have been assigned to the heterocyst from time to time. Their role in akinete formation is suggested ...

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Physiology and cytological chemistry blue-green algae.

Abstract: Light and temperature. Synchronous growth.66 Means of obtaining pure cultures.66 Growth of single cells .66 Substances ted; Toxins.66 Regulation and Development..67 Biochemical regulation..67 Chromatic variation..67 Development of Nostoc muscorum,..68 Spores (akinetes)...68

Cited by 189 publications

References 375 publications

Differences in mRNA levels in Anabaena living freely or in symbiotic association with Azolla.

Differences in mRNA levels in Anabaena living freely or in symbiotic association with Azolla.

The Heterocysts of the Blue‐green Alga Nostochopsis Lobatus: Effects of Cultural Conditions

The Heterocysts of Blue‐green Algae (Myxophyceae)

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