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 Effects of growth retarding compounds on chlorophyll accumulation and nitrate reductase activity in nitrate induced cucumber cotyledons

2015 ◽  
Vol 42 (3) ◽  
pp. 431-439 ◽  
Author(s):  
J. S. Knypl
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Chlorophyll Synthesis ◽  
Growth Retardants ◽  
Chlorophyll Accumulation ◽  
High Concentrations ◽  
Amo 1618 ◽  
Nr Activity

Cotyledons were excised from 5-day old etiolated cucumber seedlings and .grown for 24 or 48 h in solutions of plant growth retardants: AMO-1618,B-Nine, CCC and phosfon D, supplemented with KNO<sub>3</sub> (10<sup>-2</sup>M) in light. Nitrate reductase (NR) activity was determined <i>in vivo</i>. CCC and Phosfon D at high concentrations had no effect on nitrate reductase activity in 24 h tests. CCC at 5xl0<sup>-2</sup> M enhanced NR activity in longer 48 h tests; Phosfon D was inhibitory in that case. AMO-1618 markedly decreased NR activity. B-Nine strikingly enhanced NR activity in KNO<sub>3</sub> induced cytoledons; the effect was positively correlated with the concentration of B-Nine. Ali the compounds inhibited chlorophyll synthesis.

Benzyladenine as a regulator of chlorophyll synthesis in cucumber cotyledons

1971 ◽  
Vol 49 (12) ◽  
pp. 2197-2201 ◽  
Author(s):  
R. A. Fletcher ◽  
Dianne McCullagh
Keyword(s):  
Aminolevulinic Acid ◽  
Chlorophyll Biosynthesis ◽  
Chlorophyll Synthesis ◽  
Lag Phase ◽  
Rna And Protein Synthesis ◽  
Chlorophyll Production ◽  
Cucumber Cotyledons ◽  
Ala Synthetase ◽  
Rate Limiting ◽  
Chlorophyll Formation

Pretreatment of etiolated cucumber cotyledons (4–10 days old) with benzyladenine (BA) increased the amount of chlorophyll produced in light. BA also eliminated the lag phase in chlorophyll formation, which in the water controls lasted for [Formula: see text]. Addition of δ-aminolevulinic acid (ALA) to the etiolated cotyledons resulted in the production of protochlorophyllide (PCHLD) in the dark. The BA-pretreated cotyledons did not make any PCHLD in the dark. The inhibitors of RNA and protein synthesis, actinomycin D, chloramphenicol, and cycloheximide (CH), inhibited BA's effect on chlorophyll production, with CH being the most effective. We propose that BA's effect on increased chlorophyll formation is mediated by inducing production of proteins including ALA synthetase, the rate-limiting enzyme in chlorophyll biosynthesis.

ON THE CLAIMED ‘ADAPTIVE’ NATURE OF IAA-OXIDASE AND AN EFFECT OF GREEN LIGHT ON IAA-OXIDASE ACTIVITY

1965 ◽  
Vol 43 (8) ◽  
pp. 885-892 ◽  
Author(s):  
William G. Boll
Keyword(s):  
Oxidase Activity ◽  
Green Light ◽  
Lag Phase ◽  
Iaa Oxidase ◽  
Photo Effect ◽  
Published Evidence ◽  
Adaptive Nature ◽  
Light Maximum ◽  
Maximum Transmission

This paper examines the claim by Galston and Dalberg (Am. J. Botany, 41, 373 (1954), that IAA-oxidase is an adaptive enzyme, by which was meant that it is an enzyme formed as a consequence of the presence of IAA. Certain of the published evidence is rejected as irrelevant to the question.It is shown here that crude IAA-oxidase preparations from etiolated pea buds show a lag phase in IAA destruction whereas this is not so with enzyme from hook tissue or older stem tissue.Pretreatment of hook tissue or older tissue with IAA did not increase IAA-oxidase activity. It is confirmed that IAA-oxidase preparations from buds pretreated with IAA gave more destruction of IAA, when measured after 60 minutes, than did enzyme from untreated buds. This difference occurred because of elimination of the lag phase in destruction and not because of induced formation of enzyme.The lag phase in IAA-oxidase activity with enzyme extracted from buds was increased by exposing the seedlings to 3 minutes of weak green light (maximum transmission 520 mμ) at 16 hours before harvest. Pretreatment of such light-treated buds with IAA did not completely eliminate the lag phase in IAA-oxidase activity. It is suggested that these effects of green light are a new photo-effect in plants.

Macromolecular Physiology Of Plastids

1974 ◽  
Vol 15 (1) ◽  
pp. 31-55
Author(s):  
K. W. HENNINGSEN ◽  
J. E. BOYNTON
Keyword(s):  
Small Diameter ◽  
Chlorophyll Synthesis ◽  
Prolamellar Body ◽  
Lag Phase ◽  
Plastid Development ◽  
Structural Reorganization ◽  
Chlorophyll Accumulation ◽  
Young Leaves ◽  
Plastid Membranes ◽  
Structural Aspects

The development of plastid membranes was studied in relation to chlorophyll accumulation in dark-grown barley seedlings of various ages after transfer to light. Quantitative electron microscopy showed that the prolamellar body membranes are reorganized into primary lamellar layers which contain sufficient membranes to support grana formation during 24 h of greening. Structural reorganization of the plastid membranes is completed rapidly in young seedlings, but is slow in older seedlings. Chlorophyll accumulates rapidly in young leaves after a short lag. In older leaves there is a longer lag phase before the onset of chlorophyll synthesis, and the final rate of synthesis is lower. Shortly after transferring to light, the crystalline prolamellar bodies in the etioplasts are transformed and then dispersed into lamellar layers with numerous perforations and protuberances. Before the phase of rapid chlorophyll synthesis, many small-diameter 2-disk grana are formed. When chlorophyll begins to accumulate, the perforations are rapidly eliminated from the lamellar layers and a maximum number of 2-disk grana are formed. As greening proceeds additional disks are added to these original 2-disk grana. During the phase of rapid chlorophyll synthesis, pairing of the lamellae is positively correlated with the accumulation of chlorophyll. During greening less chlorophyll appears to be incorporated into the paired regions of the lamellae in young leaves as compared to old leaves. The results on the structural aspects of plastid development are discussed in relation to the formation of photosynthetic capacity.

Stimulation of chlorophyll synthesis in cucumber cotyledons by benzyladenine

1973 ◽  
Vol 51 (5) ◽  
pp. 937-939 ◽  
Author(s):  
R. A. Fletcher ◽  
C. Teo ◽  
A. Ali
Keyword(s):  
Total Synthesis ◽  
Aminolevulinic Acid ◽  
Chlorophyll Biosynthesis ◽  
Chlorophyll Synthesis ◽  
Lag Phase ◽  
Cucumber Cotyledons ◽  
Ala Synthetase ◽  
Rate Limiting ◽  
Chlorophyll Formation ◽  
Stimulation Of

When exposed to light, etiolated cucumber cotyledons exhibited a lag phase in chlorophyll biosynthesis. Pretreatment of the cotyledons with benzyladenine (BA) eliminated the lag phase and stimulated chlorophyll formation. In BA-treated cotyledons, the incorporation of 14C-leucine into protein and the total synthesis of protein were higher than in the non-BA-treated controls. After BA treatment and exposure to light, the accumulation of δ-aminolevulinic acid in the cotyledons increased with time and was higher than in the controls, where a lag phase was apparent. These results support our hypothesis that BA affects chlorophyll formation by inducing the production of proteins including ALA-synthetase, the rate-limiting enzyme in chlorophyll biosynthesis.

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.

Impairment of Platelet Aggregation by Echis colorata Venom Mediated by L-Amino Acid Oxidase or H2O2

1982 ◽  
Vol 48 (03) ◽  
pp. 277-282 ◽  
Author(s):  
I Nathan ◽  
A Dvilansky ◽  
T Yirmiyahu ◽  
M Aharon ◽  
A Livne
Keyword(s):  
Hydrogen Peroxide ◽  
Amino Acid ◽  
Platelet Aggregation ◽  
Snake Venom ◽  
Oxidase Activity ◽  
Enzyme Preparation ◽  
Acid Oxidase ◽  
Crude Venom ◽  
Amino Acid Oxidase ◽  
Hemostatic Disorders

SummaryEchis colorata bites cause impairment of platelet aggregation and hemostatic disorders. The mechanism by which the snake venom inhibits platelet aggregation was studied. Upon fractionation, aggregation impairment activity and L-amino acid oxidase activity were similarly separated from the crude venom, unlike other venom enzymes. Preparations of L-amino acid oxidase from E.colorata and from Crotalus adamanteus replaced effectively the crude E.colorata venom in impairment of platelet aggregation. Furthermore, different treatments known to inhibit L-amino acid oxidase reduced in parallel the oxidase activity and the impairment potency of both the venom and the enzyme preparation. H2O2 mimicked characteristically the impairment effects of L-amino acid oxidase and the venom. Catalase completely abolished the impairment effects of the enzyme and the venom. It is concluded that hydrogen peroxide formed by the venom L-amino acid oxidase plays a role in affecting platelet aggregation and thus could contribute to the extended bleeding typical to persons bitten by E.colorata.

The Effect of Castration and Testosterone Propionate on d-Amino Acid Oxidase Activity in the Mouse

Science ◽  
1943 ◽  
Vol 98 (2534) ◽  
pp. 89-89
Author(s):  
L. C. Clark ◽  
C. D. Kochakian ◽  
R. Phyllis Fox
Keyword(s):  
Amino Acid ◽  
Oxidase Activity ◽  
Testosterone Propionate ◽  
Acid Oxidase ◽  
Amino Acid Oxidase

The heme moiety in peanut peroxidase

1984 ◽  
Vol 62 (11) ◽  
pp. 1046-1050 ◽  
Author(s):  
R. N. Chibbar ◽  
R. Cella ◽  
R. B. Van Huystee
Keyword(s):  
Peroxidase Activity ◽  
Active Site ◽  
Oxidase Activity ◽  
Indoleacetic Acid ◽  
Iaa Oxidase ◽  
Equimolar Ratio ◽  
Immunological Properties ◽  
Peanut Peroxidase

Heme is present in an equimolar ratio to the apoprotein in the major cationic fraction of peanut peroxidase. The removal of heme from the holoenzyme does not affect the physicochemical and immunological properties of the apoperoxidase, however peroxidase activity is completely lost. The indoleacetic acid (IAA) oxidase activity of the apoperoxidase is reduced to 1/20 of the original holoenzyme. Both the peroxidase and IAA-oxidase activity could partially be restored in the holoenzyme reconstituted with hemin. It is suggested that heme may also participate in the IAA-oxidase activity possibly by altering the active site.

Sign in / Sign up

Export Citation Format

Share Document