scholarly journals The relationship of root-cap slimes to proteins

1974 ◽  
Vol 139 (3) ◽  
pp. 525-534 ◽  
Author(s):  
Kenneth Wright ◽  
D. H. Northcote
Keyword(s):  
Chemical Characteristic ◽  
Wheat Root ◽  
Root Cap ◽  
Water Soluble ◽  
Maize Root ◽  
Root Tip ◽  
Root Tips ◽  
Maize Roots ◽  
Neutral Sugars ◽  
Relationship Of

1. The patterns of incorporation of radioactivity from d-[U-14C]glucose into the pectic components of sections of sycamore roots changed so that sections nearer the tip incorporated relatively more label into arabinose and galactose compared with uronic acid. 2. Radioactive maize root-cap slime was prepared and found to contain three water-soluble component polymers which were electrophoretically (i) neutral, (ii) weakly acidic and (iii) strongly acidic at pH6.5. The neutral component was a glucan. The other components, which could be degraded by trans-elimination, consisted of an acidic backbone chain composed of galacturonic acid and glucose, attached to which were different proportions of neutral sugars. Arabinose, galactose and fucose, the main neutral sugars of the weakly and strongly acidic materials, were absent from the neutral fraction. 3. Fucose was a major sugar in maize-root slime and in a slime of similar composition synthesized by a maize callus of shoot origin. Only trace amounts were found in sycamore, pea and wheat root tips, and in pectin prepared from maize roots and coleoptiles. A high proportion of fucose is therefore a chemical characteristic of maize slime, and slime synthesis indicated a state of differentiation of the tissue. 4. The similarity between the slime and pectin is discussed; slime is a form of pectin modified in such a way as to provide a hydrated protective coating around the root tip.

The influence of nitrate on the induction of nitrate reductase in maize roots

1973 ◽  
Vol 51 (6) ◽  
pp. 1255-1258 ◽  
Author(s):  
D. L. Stevens ◽  
Ann Oaks
Keyword(s):  
Nitrate Reductase ◽  
Maize Root ◽  
Lag Phase ◽  
Root Tips ◽  
Final Level ◽  
Maize Roots ◽  
Mature Root

A concentration of 10 mM NO3 saturates the induction of nitrate reductase in maize root tips whereas concentrations up to 100 mM do not saturate the induction in mature root sections. Increasing concentrations of nitrate from 1 to 25 mM have no effect on either the lag phase, or the phase of rapid increase of the enzyme. They do influence the final level of enzyme obtained at 8 h.

The effect of cycloheximide on amide formation in maize roots

1973 ◽  
Vol 51 (1) ◽  
pp. 91-95 ◽  
Author(s):  
Ann Oaks ◽  
F. J. Johnson
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Root Tip ◽  
Minor Effect ◽  
Root Tips ◽  
Corn Root ◽  
Basic Amino Acids ◽  
Maize Roots ◽  
A Minor ◽  
Mature Root

Cycloheximide inhibits the incorporation of acetate-2-14C into protein and into asparagine in corn root tips. It also causes an accumulation of glutamine and, over a concentration range of 0.4 to 5.0 μg/ml, a transient accumulation of the neutral and basic amino acids. In mature sections, cycloheximide inhibits protein synthesis but causes an increase in the incorporation of radioactivity into both glutamine and asparagine. Azaserine, a glutamine analogue, also inhibits the formation of asparagine in root-tip sections but has only a minor effect on protein synthesis. In mature root sections, there is an accumulation of glutamine but no effect on asparagine formation when azaserine is used. Glutamine additions to root tips or mature root sections affect neither asparagine formation nor protein synthesis. We conclude that cycloheximide is behaving as a glutamine analogue in its effect on asparagine biosynthesis, and that its effect as a glutamine analogue is lost as cells mature.

Cell synchronization and isolation of metaphase chromosomes from maize (Zea mays L.) root tips for flow cytometric analysis and sorting

Genome ◽  
1996 ◽  
Vol 39 (4) ◽  
pp. 697-703 ◽  
Author(s):  
Jai-Heon Lee ◽  
K. Arumuganathan ◽  
S. M. Kaeppler ◽  
C. M. Papa ◽  
H. F. Kaeppler
Keyword(s):  
Cell Cycle ◽  
Flow Cytometric Analysis ◽  
Maize Root ◽  
Root Tip ◽  
Root Tips ◽  
Chromosome Sorting ◽  
Synthesis Inhibitor ◽  
Metaphase Chromosomes ◽  
Flow Karyotype ◽  
Flow Cytometric

Accumulation of cells containing metaphase chromosomes is an important step in cytological analyses and chromosome sorting procedures. The goal of this research was to optimize treatment parameters to synchronize the cell cycle of maize root tip meristem cells. Levels of hydroxyurea, a DNA synthesis inhibitor, were assessed for their utility in accumulating cells at the G1 phase of the cell cycle. Trifluralin, amiprophos-methyl, and colchicine were used to accumulate cells containing metaphase chromosomes upon release from hydroxyurea inhibition. Optimal mitotic indices were achieved by treating seedlings with 5 mM hydroxyurea for 18 h, incubating for 1 h without chemical treatment to release the hydroxyurea block, and then treating emerging roots with 1 μM trifluralin for 4 h. The mitotic index of synchronized maize root tips was over 70%. Uniformity of synchronization depended upon selection of seeds with emerging radicles that were similar in length at the time of treatment. Suspensions of intact chromosomes were prepared by a simple slicing procedure. The chromosome preparations were found to be suitable for flow cytometric characterization and sorting. Chromosome peaks of the observed flow karyotype resembled the predicted flow karyotype calculated on the basis of maize chromosome size. Key words : flow karyotype, hydroxyurea, plant chromosome sorting, trifluralin.

scholarly journals Polyprenyl phosphate sugars synthesized during slime-polysaccharide production by membranes of the root-cap cells of maize (Zea mays)

1979 ◽  
Vol 178 (3) ◽  
pp. 661-671 ◽  
Author(s):  
J R Green ◽  
D H Northcote
Keyword(s):  
Endoplasmic Reticulum ◽  
Zea Mays ◽  
Neutral Lipids ◽  
Root Tip ◽  
Synthetase Activity ◽  
Root Tips ◽  
Maize Roots ◽  
Glucose Derivatives

Two types of experiments were carried out; either maize roots were incubated in L-[1-3H]fucose or membranes were prepared from root tips and these were incubated with GDP-L-[U-14C]fucose or UDP-D-[U-4C]glucose. The radioactively labelled lipids that were synthesized in vivo and in vitro were extracted and separated into polar and neutral components. The polar lipids had the characteristics of polyprenyl phosphate and diphosphate fucose or glucose derivatives, and the neutral lipids of sterol glycosides (fucose or glucose). A partial separation of the glycolipid synthetase reactions was achieved. Membranes were fractionated into material that sedimented at 20,000g and 100,000g. Most of the polar glycolipid synthetase activity (for the incorporation of both fucose and glucose) was located in the 100,000 g pellet, and this activity was probably located in the endoplasmic reticulum. The neutral lipid, which contained fucose, was synthesized mainly by membranes of the 20,000g pellet, and the activity was probably associated with the dictyosomes, whereas the neutral glucolipids were synthesized by all the membrane fractions. It is suggested that the polar (polyprenyl) lipids labelled with fucose could act as possible intermediates during the synthesis of the glycoproteins and slime in the root tip.

scholarly journals Facilitated transport of Mn2+ in sycamore (Acer pseudoplatanus) cells and excised maize root tips. A comparative 31P n.m.r. study in vivo

1988 ◽  
Vol 252 (2) ◽  
pp. 401-408 ◽  
Author(s):  
C Roby ◽  
R Bligny ◽  
R Douce ◽  
S I Tu ◽  
P E Pfeffer
Keyword(s):  
Metal Ion ◽  
Plasma Membranes ◽  
Maize Root ◽  
Root Tip ◽  
Acer Pseudoplatanus ◽  
Relative Distribution ◽  
Root Tips ◽  
Root Cells ◽  
Hypoxic Conditions

Movement of paramagnetic Mn2+ into sycamore (Acer pseudoplatanus) cells has been indirectly examined by observing the line broadening exhibited in its 31P n.m.r. spectra. Mn2+ was observed to pass into the vacuole, while exhibiting a very minor accumulation in the cytoplasm. With time, gradual leakage of phosphate from the vacuole to the cytoplasm was observed along with an increase in glucose-6-phosphate. Anoxia did not appear to affect the relative distribution of Mn2+ in the cytoplasm and vacuole. Under hypoxic conditions restriction of almost all movement of Mn2+ across the plasmalemma as well as the tonoplast was observed. In contrast, maize root tips showed entry and complete complexation of nucleotide triphosphate by Mn2+ during hypoxia. The rate of passage of Mn2+ across the tonoplast in both sycamore and maize root cells is approximately the same. However, the rates of facilitated movement across the respective plasma membranes appear to differ. More rapid movement of Mn2+ across the plasmalemma in maize root tip cells allows a gradual build-up of metal ion in the cytoplasm prior to its diffusion across the tonoplast. Sycamore cells undergo a slower uptake of Mn2+ into their cytoplasms (comparable with the rate of diffusion through the tonoplast), so little or no observable accumulation of Mn2+ is observed in this compartment.

Changes in nitrogen metabolism in the wheat root tip following growth and vernalization

1970 ◽  
Vol 48 (4) ◽  
pp. 671-681 ◽  
Author(s):  
Geneviève Ste-Marie ◽  
Pearl Weinberger
Keyword(s):  
Glutamic Acid ◽  
Wheat Root ◽  
Alanine Transaminase ◽  
Developmental Changes ◽  
Root Tip ◽  
Acid Fraction ◽  
Root Tips ◽  
Acid Incorporation ◽  
Control Root ◽  
And Control

Sequential changes in the alcohol-soluble amino acid fraction of vernalized and control root tips of Triticum aestivum var. Marquis (spring) and Rideau (winter) wheats have been followed. Substantial changes in this fraction could be related to developmental changes in the root tip, with protein synthesis occurring most rapidly in the region of elongation. Vernalization superimposed additional, consistent changes mainly in the content of asparagine, glutamine, glycine, and glutamic acid. Incorporation studies using 14C-glutamic acid and aspartic acid served to emphasize the distinct metabolic differences between the mitotic and elongating regions of the root tips. The activity of glutamic acid – alanine transaminase was also studied.

scholarly journals A Root Tip-Specific Expressing Anthocyanin Marker for Direct Identification of Transgenic Tissues by the Naked Eye in Symbiotic Studies

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 605
Author(s):  
Yiting Ruan ◽  
Ke Chen ◽  
Yangyang Su ◽  
Suyu Jiang ◽  
Ping Xu ◽  
...  
Keyword(s):  
Root Cap ◽  
Root Tip ◽  
Root Tips ◽  
Reporter System ◽  
Specific Expression ◽  
Transgenic Roots ◽  
Fluorescent Reporters ◽  
Naked Eye ◽  
Root Transformation ◽  
Transgenic Hairy Roots

The Agrobacterium rhizogenes hairy root transformation system is widely used in symbiotic studies of model legumes. It typically relies on fluorescent reporters, such as DsRed, for identification of transgenic roots. The MtLAP1 transcription factor has been utilized as a reporter system in Medicago truncatula based on production of anthocyanin pigment. Here, we describe a version of this reporter driven by a root-cap specific promoter for direct observation of anthocyanin accumulation in root tips, which allows the identification of transgenic hairy roots by the naked eye. Results from our analysis suggest that the reporter had no significant effects on nodulation of M. truncatula. This approach, by virtue of its strong and specific expression in root cap cells, greatly reduces false positives and false negatives, and its use of an easily scored visible pigment should allow greater versatility and efficiency in root biology studies.

scholarly journals Distinct changes in mature root and growing root tip proteomes underlie physiological responses of bread wheat to salinity stress

2021 ◽  
Author(s):  
Bhagya M Dissanayake ◽  
Christiana Staudinger ◽  
Rana Munns ◽  
Nicolas L Taylor ◽  
A. Harvey Millar
Keyword(s):  
Protein Synthesis ◽  
Tca Cycle ◽  
Wheat Root ◽  
Root Tip ◽  
Root Tips ◽  
Wheat Roots ◽  
Root Tissues ◽  
Related Proteins ◽  
The Impact ◽  
Mature Root

The impact of salinity on wheat plants is often studied by analysis of shoot responses, even though the main mechanism of tolerance is shoot Na+ exclusion. There is a need to understand the molecular responses of root tissues that directly experience rising NaCl concentrations. We have combined analysis of root growth, ion content and respiration with proteome responses in wheat root tip and mature root tissues under saline conditions. We find significant changes in translation and protein synthesis, energy metabolism and amino acid metabolism in a root tissue specific manner. Translation and protein synthesis related proteins showed significant decreases in abundance only in root tips, as did most of the glycolytic enzymes and selected TCA cycle enzymes and ATP synthase subunits. This selective root tip proteome response indicates protein synthesis capacity and energy production were impaired under salt stress, correlating with the anatomical response of roots and reduced root tip respiration rate. Wheat roots respond directly to soil salinity, therefore shoot responses such as reduction in shoot growth and photosynthetic capacity need to be considered in light of these effects.

Isolation and characterization of membranes from the cells of maize root tips

1980 ◽  
Vol 45 (1) ◽  
pp. 147-167
Author(s):  
E.A. Baydoun ◽  
D.H. Northcote
Keyword(s):  
Choline Chloride ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sucrose Density Gradient ◽  
Maize Root ◽  
Root Tips ◽  
Isolation And Characterization ◽  
Maize Roots ◽  
Endomembrane Flow ◽  
Polypeptide Chains

A discontinuous sucrose density gradient was used to separate membrane fractions from a homogenate of maize root tips. Endoplasmic reticulum-, Golgi apparatus-, plasma membrane- and mitochondria-rich fractions were identified by their enzymic characteristics and by their appearance under the electron microscope. Maize roots were incubated in vivo with D-[U-14C]glucose, [Me-14C]choline chloride and diazotized [U-3H]sulphanilic acid. The pattern of incorporation of radioactivity into the various membrane fractions was investigated. Analyses of the polypeptide chains of the membrane fractions by SDS-polyacrylamide gel electrophoresis showed that the mitochondria-rich fraction had a different pattern of polypeptides from that of the other membrane fractions. The results are discussed in relation to the hypothesis of endomembrane flow and differentiation.

The regulation of proline biosynthesis in maize roots

1970 ◽  
Vol 48 (12) ◽  
pp. 2249-2258 ◽  
Author(s):  
Ann Oaks ◽  
D. J. Mitchell ◽  
R. A. Barnard ◽  
F. J. Johnson
Keyword(s):  
Product Inhibition ◽  
Maize Root ◽  
Root Tip ◽  
Proline Biosynthesis ◽  
Maize Roots

Proline or the proline analogues hydroxy-L-proline and azetidine-2-COOH inhibit the formation of proline from acetate-2-14C or glutamate-UL-14C in the 5-mm maize root tip. The inhibition of the incorporation of acetate-derived proline into protein is more severe than the inhibition of the total biosynthesis (soluble plus insoluble proline-14C). The results suggest that a portion of the proline biosynthesis, which becomes more prominent as the cells mature, is refractory to end product inhibition. The results also show that simultaneous additions of glucose promote the incorporation of proline-UL-14C into protein, exaggerate its accumulation as soluble proline, and reduce its oxidation.

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