scholarly journals Dynamics of indole-3-acetic acid oxidase activity in suspension culture of sunflower crown-gall

2014 ◽  
Vol 53 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Zofia Chirek
Keyword(s):  
Suspension Culture ◽  
Crown Gall ◽  
Oxidase Activity ◽  
Middle Part ◽  
Acid Oxidase ◽  
Iaa Oxidase ◽  
Auxin Level ◽  
Feedback Type ◽  
Indole 3 Acetic Acid ◽  
Intensive Growth

IAA oxidase activity was determined in several growth phases of a suspension culture of sunflower crown-gall. During the short phase of intensive growth (zero passage - PO) a negative correlation was noted between enzymatic activity and the rate of growth. IAA oxidase activity increased to a certain level is not a factor limiting cell division. For protraction of the phase of intensive growth (first passage - P1), however, a decrease in the activity of this enzyme seems indispensable. IAA oxidase activity in the tested culture is under the control of inhibitors present in the cells and medium. High enzyme inhibition was observed in PO cells during the phase, of intensive growth and in P1 at the beginning and in the middle part of this phase. These results suggest' that the -auxin level determined in earlier studies in sunflower crown-gall culture is controlled by the IAA oxidase set. During the long phase of intensive growth (P1) this control is of negative feedback type.

Isoperoxidases of (IAA oxidase) oxidase in oat coleoptiles

1973 ◽  
Vol 51 (11) ◽  
pp. 2047-2052 ◽  
Author(s):  
William R. Gordon ◽  
James H. M. Henderson
Keyword(s):  
Acetic Acid ◽  
Avena Sativa ◽  
Gel Electrophoresis ◽  
Enzyme Assay ◽  
Polyacrylamide Gel Electrophoresis ◽  
Acid Oxidase ◽  
Iaa Oxidase ◽  
Substrate Specificities ◽  
Electrophoretic Mobilities ◽  
Indole 3 Acetic Acid

Eight constitutive isoperoxidases were separated by the disc method of polyacrylamide gel electrophoresis from a lyophilized extract of 8-day-old oat (Avena sativa L., cv. Victory) coleoptiles. Both anodic and cathodic isoperoxidases were studied and differences in electrophoretic mobilities and hydrogen donor substrate specificities were revealed. In addition, by enzyme assay, cathodic and anodic isoenzymes were shown to possess differences in peroxidase and IAA (indole-3-acetic acid) oxidase activities.Treatment of coleoptiles with 0.07 mM IAA for 24 h resulted in the repression of two slow-migrating anodic isoperoxidases; however, the same treatment also resulted in the induction of two slow-migrating cathodic isoenzymes which were shown to exhibit peroxidase and IAA oxidase activities.

scholarly journals No effect of plant growth retarding compounds and growth stimulators on indolo-3-acetic acid oxidase activity in greening cucumber cotyledons

2015 ◽  
Vol 42 (3) ◽  
pp. 441-452 ◽  
Author(s):  
J. S. Knypl
Keyword(s):  
Oxidase Activity ◽  
Chlorophyll Synthesis ◽  
Lag Phase ◽  
Acid Oxidase ◽  
Iaa Oxidase ◽  
Crude Enzyme Extract ◽  
Chlorophyll Accumulation ◽  
Cucumber Cotyledons ◽  
Amo 1618 ◽  
Molecular Sieving

Cotyledons dissected from 5-day-old etiolated cucumber seedlings were incubated in solutions on AMO-1618, B-Nine, CCC and Phosfon D for 48 h in light. In some tests the retardants were applied in mixed solutions with GA<sub>3</sub> or BAP. IAA oxidase was extracted and purified by means of molecular sieving through a bed of Sephadex G-25. The retardants inhibited chlorophyll synthesis by 50 % or more, and had essentially no effect on IAA oxidase activity per cotyledon basis. GA<sub>3</sub> and BAP also had no effect on enzyme activity in spite of a fact that the compounds stimulated growth of the cotyledons. The crude enzyme extract from B-Nine treated cotyledons showed lower IAA oxidase activity in comparison with the water treated control, the effect being due to a longer lag-phase preceding the initiation of IAA oxidation. KNO<sub>3</sub> strikingly stimulated expansional growth of the cotyledons, the effect being correlated with the accelerated chlorophyll accumulation. KNO<sub>3</sub> had no effect on IAA oxidase activity per cotyledon and decreased it per gram fr wt. It is concluded that [1] the growth rate of cucumber cotyledons is not correlated with IAA oxidase activity, and ;[2] the growth retarding compounds do not affect IAA oxidase system is this tissue.

scholarly journals Changes in auxin level in the course of growth of a sunflower crown-gall suspension culture

2014 ◽  
Vol 52 (3-4) ◽  
pp. 285-294 ◽  
Author(s):  
Zofia Chirek
Keyword(s):  
Suspension Culture ◽  
Crown Gall ◽  
Culture Medium ◽  
Cell Mass ◽  
Maximum Growth ◽  
Maximal Growth ◽  
Auxin Level ◽  
Culture Cycle ◽  
Crown Gall Tumour ◽  
Further Development

The auxin level in the cell mass and culture medium was determined by means of the <em>Avena</em> straight caleoptile test in various periods of the suspension culture cycle of the sunflower crown-gall tumour. The investigations were performed in the course of the zero passage (PO) and first one (Pl), differing in their time of duration of maximum growth and its intensity. In both passages the intra- and extra-cellular auxin levels reach values of the same order. At the beginning of the maximal growth phase the activity corresponding to IAA in the cells prevails over that of the other auxin-like compounds. This disproportion diminishes with further development of the culture, and with the beginning of the stationary phase the cellular IAA level is lower than that of the remaining auxin-like compounds. The short phase of maximal growth (PO) occurs with an auxin level decreasing in the cell mass and increasing in the medium, and towards the end of the cycle these levels become equal. During the long phase of maximal growth (Pl) the total amount of auxins in the cells increases and is 2-3 times higher than in the medium, whereas IAA in the cells remains at a constant level. These results suggest that the participation of IAA in the intracellular pool of auxin-like substances is decisive for the mitotic activity of the cells and maintenance of growth in the culture.

Constitutive isoflavones as modulators of indole-3-acetic acid oxidase activity of acidic cell wall isoperoxidases from lupin hypocotyls

1992 ◽  
Vol 31 (11) ◽  
pp. 3681-3684 ◽  
Author(s):  
María A. Ferrer ◽  
María A. Pedreño ◽  
Romualdo Muñoz ◽  
A.Ros Barceló
Keyword(s):  
Cell Wall ◽  
Acetic Acid ◽  
Oxidase Activity ◽  
Acid Oxidase ◽  
Indole 3 Acetic Acid
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