Cyclic Adenosine 3′:5′-Monophosphate in Moss Protonema

Handa, Avtar K.; Johri, M. M.

doi:10.1104/pp.59.3.490

Cited by 41 publications

(9 citation statements)

References 12 publications

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“…Cyclic AMP and cyclic AMP-specific phosphodiesterases have been demonstrated in the chloronemal cells (Handa and Johri, 1977;Sharma and Johri, 1982). A far higher level of intracellular cAMP in chloronema than in caulonema and the stimulation of chloronema formation by the inhibitors of cyclic nucleotide phosphodiesterase are consistent with the role of endogenous cAMP (Handa and Johri, 1979).…”

Section: Stimulation Of Chloronema Differentiation By 3'5'-cyclic Ampmentioning

confidence: 67%

Hormonal regulation in green plant lineage families

Johri

2008

Physiol Mol Biol Plants

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The patterns of phytohormones distribution, their native function and possible origin of hormonal regulation across the green plant lineages (chlorophytes, charophytes, bryophytes and tracheophytes) are discussed. The five classical phytohormonesauxins, cytokinins, gibberellins (GA), abscisic acid (ABA) and ethylene occur ubiquitously in green plants. They are produced as secondary metabolites by microorganisms. Some of the bacterial species use phytohormones to interact with the plant as a part of their colonization strategy. Phytohormone biosynthetic pathways in plants seem to be of microbial origin and furthermore, the origin of high affinity perception mechanism could have preceded the recruitment of a metabolite as a hormone. The bryophytes represent the earliest land plants which respond to the phytohormones with the exception of gibberellins. The regulation by auxin and ABA may have evolved before the separation of green algal lineage. Auxin enhances rhizoid and caulonemal differentiation while cytokinins enhance shoot bud formation in mosses. Ethylene retards cell division but seems to promote cell elongation. The presence of responses specific to cytokinins and ethylene strongly suggest the origin of their regulation in bryophytes. The hormonal role of GAs could have evolved in some of the ferns where antheridiogens (compounds related to GAs) and GAs themselves regulate the formation of antheridia.During migration of life forms to land, the tolerance to desiccation may have evolved and is now observed in some of the microorganisms, animals and plants. Besides plants, sequences coding for late embryogenesis abundant-like proteins occur in the genomes of other anhydrobiotic species of microorganisms and nematodes. ABA acts as a stress signal and increases rapidly upon desiccation or in response to some of the abiotic stresses in green plants. As the salt stress also increases ABA release in the culture medium of cyanobacterium Trichormus variabilis, the recruitment of ABA in the regulation of stress responses could have been derived from prokaryotes and present at the level of common ancestor of green plants. The overall hormonal action mechanisms in mosses are remarkably similar to that of the higher plants. As plants are thought to be monophyletic in origin, the existence of remarkably similar hormonal mechanisms in the mosses and higher plants, suggests that some of the basic elements of regulation cascade could have also evolved at the level of common ancestor of plants. The networking of various steps in a cascade or the crosstalk between different cascades is variable and reflects the dynamic interaction between a species and its specific environment.

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Section: Stimulation Of Chloronema Differentiation By 3'5'-cyclic Ampmentioning

confidence: 67%

Hormonal regulation in green plant lineage families

Johri

2008

Physiol Mol Biol Plants

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“…Accordingly, in the present study 1 g of alumina/g fresh wt was employed to ensure virtually complete removal of inhibitory material (about 250 pmol of "cAMP equivalent"/g fresh wt) from rye grass extracts. While the saturation assay inhibitor(s) encountered in rye grass, K. daigremontiana (5), moss protonema (12), and a variety of higher plants (1,6) are not necessarily similar chemically, the procedures used in the present study have been effective in resolving such inhibitors from cAMP in extracts from several higher plants and may be useful in further biochemical estimations of higher plant cAMP levels. Unfortunately, the saturation assay appears to be considerably more sensitive to such inhibitors than the protein kinase activation assay (6,12), while it is analytically the more sensitive assay.…”

Section: B and C) (B)mentioning

confidence: 99%

“…While the saturation assay inhibitor(s) encountered in rye grass, K. daigremontiana (5), moss protonema (12), and a variety of higher plants (1,6) are not necessarily similar chemically, the procedures used in the present study have been effective in resolving such inhibitors from cAMP in extracts from several higher plants and may be useful in further biochemical estimations of higher plant cAMP levels. Unfortunately, the saturation assay appears to be considerably more sensitive to such inhibitors than the protein kinase activation assay (6,12), while it is analytically the more sensitive assay. Given the very low levels of cAMP in higher plants, application of effective purification procedures of the kind described here are required before unambiguous saturation assays-including highly sensitive radioimmuno assays (8)-can be applied to cAMP-containing fractions from plants.…”

Section: B and C) (B)mentioning

confidence: 99%

“…Thus, in the detailed studies by Bressan et al (6) and Handa and Johri (12) the levels of cAMP determined by the saturation assay were 7 to 20 times the levels determined by the protein kinase assay in some cases, and the presence of non-cAMP inhibitory material was apparent from chromatographic separations. In both of these studies a cation exchange chromatography step was employed in the purification of the cAMP fraction-the samples in both cases being applied to and eluted from the Dowex 50 or Aminex MS in H20 (6,12). This procedure was found to be ineffective for separation of inhibitor and cAMP on AG 50W (Dowex 50) in our previous studies with K daigremontiana; however chromatography on 0.1 N HCI was found to retard cAMP sufficiently to permit complete separation from inhibitory material (unpublished data).…”

Section: B and C) (B)mentioning

confidence: 99%

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Cyclic Adenosine 3′:5′-Monophosphate in Axenic Rye Grass Endosperm Cell Cultures

Ashton¹,

Polya²

1978

Plant Physiol.

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Cyclic adenosine 3':5'-monophosphate (cAMP) was extensively purified from rye grass (Lolium multilonrum) endosperm cells grown in axenic suspension culture. The cAMP was purified by neutral alumina and anion and cation exchange chromatography. The cAMP was quantitated by means of a radiochemical saturation assay using a beef heart cAMPbinding protein and also by an assay involving activation of beef heart protein kinase. The cAMP levels found (corrected for recovery of tracer cyclic 3',5'-18-3HIAMP included from the point of sample extraction) ranged from 2 to 12 pmol/g fresh weight. TMe material purified from rye grass cultures was indistinguishable from authentic cAMP with respect to chromatography in two cellulose thin layer systems, behavior on dilution in both the saturation and protein kinase activation assays, and rates of degradation by a mammalian cAMP phospbodiesterase. The cAMP from rye grass cultures was completely degraded by a mammalian cAMP phosphodiesterase, and 1-methyl-3-isobutylxanthine inhibited such degradation. The protein kinase activation and saturation assays gave essentially the same values for the cAMP content of axenic rye grass culture extracts. Material satisfying the above criteria for identity with cAMP was also isolated from the culture medium. The increase observed in medium cAMP levels during culture growth provides evidence for the synthesis and secretion of cAMP by rye grass endosperm cells in suspension culture.The occurrence of cyclic AMP in higher plants is currently a matter of some controversy. While there have been many claims for the presence of cAMPs in higher plants, the adequacy of the evidence advanced has been questioned on many grounds (2,15). Ambiguities in previous studies derive from the presence of plant compounds that interfere with biochemical cAMP assay systems, the sensitivity of the assay systems used, the possibility of microbiological contamination, and insufficiency of criteria satisfied to support identity of the extracted plant substance with cAMP.While reported estimates of the cAMP content of higher plants range up to 10' pmol/g fresh wt (14,22) other groups, employing sensitive detection and characterization procedures, have reported that cAMP, if present at all, occurs at levels of less than 1 to 10 pmol/g fresh wt (1,6,13).In a recent study we estimated minimum cAMP levels of I and 2 to 6 pmol/g fresh wt in Kalanchoe daigremontiana and Agave americana, respectively (5 'Abbreviation: cAMP: cyclic adenosine 3':5'-monophosphate. chromatography in a variety of thin layer systems, identical behavior in saturation and protein kinase assays, and identical rates of phosphodiesterase-catalyzed degradation of the plant material and authentic cAMP (5). The microbiological contamination of the K daigremontiana and A. americana leaves was at least 103 times too low to account for the observed cAMP as being due to intracellular bacterial cAMP (5). Nevertheless a formal (albeit unlikely) possibility exists that long term, continuous secretion of cAMP ...

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“…The plants arising from these spores are again dioecious. 23 In general, it is accepted that the dioecious condition has evolutionary advantages over monoecy because monoecious plants are very often self-fertilized, producing only homozygotes. The resulting sporophyte is homozygous and thus carries the same genotype as the parental gametophyte.…”

Section: A Genotypic Sex Determinationmentioning

confidence: 99%