APPLICATION OF GAS‐LIQUID CHROMATOGRAPHY TO STUDY OF THE ENVELOPE LIPIDS OF HETEROCYSTS<sup>1</sup><sup>2</sup>

Lorch, Steven K.; Wölk, C. Peter

doi:10.1111/j.1529-8817.1974.tb02724.x

Cited by 4 publications

(4 citation statements)

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“…might be confined to specialized cells analogous to heterocysts but which do not appear different from ordinary vegetative cells on microscopic examination. The patterns of [13N]N, and 13NH,+ incorporation by Gloeocapsa (Meeks et al, 1978) support this suggestion, as does the observation that a heterocyst-type glycolipid can be found in extracts of the alga (Lorch & Wolk, 1974). However, since this glycolipid is not always apparent (Gallon et al, 1978) and is more obvious when the alga is subjected to inhibitors such as fluoroacetate than when it is fixing nitrogen maximally, it is difficult to demonstrate a direct relationship between this glycolipid and nitrogenase.…”

Section: Protection Of Gloeocapsa Sp Lb795 Nitrogenase From Inactivamentioning

confidence: 85%

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The Effects of Methyl Viologen on Gloeocapsa sp. LB795 and Their Relationship to the Inhibition of Acetylene Reduction (Nitrogen Fixation) by Oxygen

Tözüm

Gallon

1979

Journal of General Microbiology

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Methyl viologen (10 ,UM) markedly inhibited acetylene reduction (nitrogen fixation) by old but not young cultures of Gloeocapsa sp. LB795, apparently by causing the alga to produce H202. H,02 inhibited acetylene reduction when added to cultures at concentrations greater than 10 ,UM. As catalase (EC 1.11.1.6) is not present in Gloeocapsa sp. LB795, H202 is probably removed by a non-enzymic reaction with ascorbate and also by an enzymecatalysed reaction with glutathione. Enzymes catalysing the decomposition of H,O, were most active in young cells which were therefore better able than old cells to metabolize H202 produced in the presence of methyl viologen. The maximum activities of these enzymes coincided with maximum nitrogenase activity during the growth of batch cultures, and may provide a protective mechanism for nitrogenase.

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Section: Protection Of Gloeocapsa Sp Lb795 Nitrogenase From Inactivamentioning

confidence: 85%

“…Ascorbate was assayed spectrophotometrically as described by Roe (1954). Protein was measured by reference to bovine serum albumin using the method of Lowry et al (1951), as modified by Bailey (1962).…”

Section: Introductionmentioning

confidence: 99%

The Effects of Methyl Viologen on Gloeocapsa sp. LB795 and Their Relationship to the Inhibition of Acetylene Reduction (Nitrogen Fixation) by Oxygen

Tözüm

Gallon

1979

Journal of General Microbiology

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“…In addition, there are hints that lipids characteristic of heterocysts may be present in Gloeothece sp. (1,10). Further work is required to clarify whether or not nitrogenase is compartmentalized in such species.…”

Section: Assimilation Of ['"'N]n2 Incubation For Upmentioning

confidence: 99%

Pathways of assimilation of [13N]N2 and 13NH4+ by cyanobacteria with and without heterocysts

Meeks¹,

Wölk

Lockau³

et al. 1978

J Bacteriol

127

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The principal initial product of metabolism of ['3N]N2 and '3NH4' by five diverse cyanobacteria is glutamine. Methionine sulfoximine inhibits formation of [l:JN]glutamine except in the case of Gloeothece sp., an organism with a thick sheath through which the inhibitor may not penetrate. Thus, glutamine synthetase appears to catalyze the initial step in the assimilation of N2-derived or exogenous NH4' by these organisms. ['3N]Glutamate is, in all cases, the second major product of assimilation of "IN-labeled N2 and NH4+. In all of the N2-fixing cyanobacteria studied, the fraction of "N in glutamine declines and that in glutamate increases with increasing times of assimilation of ['3N]N2 and l NH4', and (Gloeothece again excepted) methionine sulfoximine reduces incorporation of`N into glutamate as well as into glutamine. Glutamate synthase therefore appears to catalyze the formation of glutamate in a wide range of N2-flxing cyanobacteria. However, the major fraction of [I:JN]glutamate formed by Anacystis nidulans incubated with "NH4' may be formed by glutamic acid dehydrogenase. The formation of ['3N]alanine from ":3NH4+ appears to be catalyzed principally either by alanine dehydrogenase (as in Cylindrospermum licheniforme) or by a transaminase (as in Anabaena variabilis). Experiments using the radioisotope '3N haveshown that in the heterocyst-forming cyanobacterium Anabaena cylindrica the major enzymatic pathway for the asimilation of NH4', whether derived from N2 or supplied exogenously, consists of glutamine synthetase (L-glutamate:ammonia ligase [ADP forming], EC 6.3.1.2) and glutamate synthase (L-glutamate:ferredoxin oxidoreductase [transaminating], EC 1.4.7.1) (11,19). Glutamic acid dehydrogenase and alanine dehydrogenase also function in the assimilation ofexogenously supplied NH41 in this cyanobacterium, but at a much lower rate even in the presence of relatively high levels of NH4+ (11). In this respect, A. cylindrica differs from some heterotrophic, dinitrogen-fixing bacteria in which N2-derived NH4+ is assimilated principally by the glutamine synthetase/ glutamate synthase pathway, whereas, during growth in the presence of high exogenous concentrations of NHEV, the NHE is assimilated via glutamic acid dehydrogenase (6).When A. cylindrica is grown aerobically, t Preent address:

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“…The outer fibrous and homogeneous layers are composed of polysaccharides (13,14), and the inner laminated layer is composed of unusual glycolipids. The glycolipids have been isolated from several cyanobacteria, and their structures have been determined (7,35,38,50,51). All of the structures described contain glucose in ␣-glycosidic linkage to a 26-or 28-carbon di-or trihydroxylated fatty acid.…”

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confidence: 99%

The hglK gene is required for localization of heterocyst-specific glycolipids in the cyanobacterium Anabaena sp. strain PCC 7120

1995

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Mutant strain 543 of the cyanobacterium Anabaena sp. strain PCC 7120 was originally isolated as a Fox ؊ mutant following chemical mutagenesis. Ultrastructural analysis shows that in nitrogen-replete media the vegetative cells of the mutant are more cylindrical and have thicker septa than those of the wild type, while in nitrogen-free media the mutant heterocysts lack the normal glycolipid layer external to the cell wall. Although this layer is absent, strain 543 heterocysts nevertheless contain heterocyst-specific glycolipids, as determined by thin-layer chromatography. The mutation in strain 543 is in a gene we have named hglK, encoding a protein of 727 amino acids. The wild-type HglK protein appears to contain four membrane-spanning regions followed by 36 repeats of a degenerate pentapeptide sequence, AXLXX. The mutation in strain 543 introduces a termination codon immediately upstream of the pentapeptide repeat region. A mutant constructed by insertion of an antibiotic resistance cassette near the beginning of the hglK gene has the same phenotype as strain 543. We propose that hglK encodes a protein necessary for the localization of heterocyst glycolipids and that this function requires the pentapeptide repeats of the HglK protein.

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APPLICATION OF GAS‐LIQUID CHROMATOGRAPHY TO STUDY OF THE ENVELOPE LIPIDS OF HETEROCYSTS¹²

Cited by 4 publications

References 12 publications

The Effects of Methyl Viologen on Gloeocapsa sp. LB795 and Their Relationship to the Inhibition of Acetylene Reduction (Nitrogen Fixation) by Oxygen

The Effects of Methyl Viologen on Gloeocapsa sp. LB795 and Their Relationship to the Inhibition of Acetylene Reduction (Nitrogen Fixation) by Oxygen

Pathways of assimilation of [13N]N2 and 13NH4+ by cyanobacteria with and without heterocysts

The hglK gene is required for localization of heterocyst-specific glycolipids in the cyanobacterium Anabaena sp. strain PCC 7120

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APPLICATION OF GAS‐LIQUID CHROMATOGRAPHY TO STUDY OF THE ENVELOPE LIPIDS OF HETEROCYSTS12

Cited by 4 publications

References 12 publications

The Effects of Methyl Viologen on Gloeocapsa sp. LB795 and Their Relationship to the Inhibition of Acetylene Reduction (Nitrogen Fixation) by Oxygen

The Effects of Methyl Viologen on Gloeocapsa sp. LB795 and Their Relationship to the Inhibition of Acetylene Reduction (Nitrogen Fixation) by Oxygen

Pathways of assimilation of [13N]N2 and 13NH4+ by cyanobacteria with and without heterocysts

The hglK gene is required for localization of heterocyst-specific glycolipids in the cyanobacterium Anabaena sp. strain PCC 7120

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APPLICATION OF GAS‐LIQUID CHROMATOGRAPHY TO STUDY OF THE ENVELOPE LIPIDS OF HETEROCYSTS¹²