Localization of nucleoside diphosphatase in the onion root tip

PROTOPLASMA ◽  
1973 ◽  
Vol 78 (4) ◽  
pp. 397-416 ◽  
Author(s):  
Charles W. Goff
Keyword(s):  
Root Tip ◽  
Onion Root ◽  
Nucleoside Diphosphatase

A CHARACTERIZATION OF NUCLEOSIDE DIPHOSPHATASE IN THE ONION ROOT TIP

1973 ◽  
Vol 21 (5) ◽  
pp. 417-425 ◽  
Author(s):  
W. D. KLOHS ◽  
C. W. GOFF
Keyword(s):  
Enzyme Activity ◽  
Lead Nitrate ◽  
Maximal Activity ◽  
Root Tip ◽  
Uridine Diphosphate ◽  
Onion Root ◽  
Guanosine Diphosphate ◽  
Inosine Diphosphatase ◽  
Triton X ◽  
Nucleoside Diphosphatase

Inosine diphosphatase of a Golgi-enriched fraction of the onion root tip was characterized. Peak enzyme activity occurred at pH 4.8 and 7.0, although considerable activity was present between the peaks. The activity at neutral pH approximately doubled during a 4-day cold storage; no such increase of the pH 4.8 activity occurred under similar conditions. Treatment with deoxycholate or Triton X-l00 also activated the pH 7.0 enzyme. Although magnesium, manganese and calcium all supported inosine diphosphatase activity, 2 mM manganese supported maximal activity. Uridine diphosphate, guanosine diphosphate and inosine diphosphate were hydrolyzed much more rapidly than the other substrates tested. Sodium fluoride, uranyl nitrate, potassium chloride and heat all partially inhibited the enzyme. Glutaraldehyde and lead nitrate, two reagents to which nucleoside diphosphatase is exposed when studied cytochemically, greatly reduced enzyme activity.

scholarly journals Nucleoside diphosphatase in the onion root tip. II. The effect of inhibitors on isoenzymes.

1977 ◽  
Vol 25 (11) ◽  
pp. 1247-1253 ◽  
Author(s):  
G D Troyer ◽  
C W Goff ◽  
W D Klohs
Keyword(s):  
Adenosine Diphosphate ◽  
Guanosine Monophosphate ◽  
Thiamine Pyrophosphate ◽  
Root Tip ◽  
Root Extract ◽  
Uridine Diphosphate ◽  
Electrophoretic Study ◽  
Onion Root ◽  
Cytidine Diphosphate ◽  
Nucleoside Diphosphatase

An electrophoretic study was performed to determine the number of isoenzymes of nucleoside diphosphatase in onion root extract. Five bands exhibiting nucleoside diphosphatase activity were detected when gels were incubated with inosine diphosphate, uridine diphosphate, guanosine diphosphate or cytidine diphosphate as substrates. These consisted of a single fast migrating band (band one), a group of three intermediate migrating bands (bands two, three and four) and a single slow migrating band (band five). Gels incubated with adenosine diphosphate, thiamine pyrophosphate, inosine monophosphate, guanosine monophosphate and cytidine monophosphate showed only two bands (bands one and five). Inhibitor studies showed that sodium fluoride inhibited bands one and five but not bands two, three and four. Conversely, 1% (v/v) glutaraldehyde inhibited bands two, three and four but did not inhibit bands one and five. These results suggest that two separate groups of onion nucleoside diphosphatase isoenzymes occur which have different substrate specificities and are selected against by certain inhibitors.

scholarly journals NUCLEOSIDE DIPHOSPHATASE IN THE ONION ROOT TIP I. EFFECTS OF FIXATION AND LEAD ON ENZYME ACTIVITY

1974 ◽  
Vol 22 (10) ◽  
pp. 945-951 ◽  
Author(s):  
C. W. GOFF ◽  
W. D. KLOHS
Keyword(s):  
Enzyme Activity ◽  
Root Tip ◽  
Fixation Time ◽  
Onion Root ◽  
Nucleoside Diphosphatase

The terminal 0.2—0.5 mm of 3-day onion roots grown from bulbs were excised and fixed for 1½ hr in various concentrations of cacodylate-buffered glutaraldehyde, formaldehyde or combinations of these. Alternatively, the fixative concentration was held constant while fixation time was varied. Control roots were run in buffer lacking fixative. The roots were then homogenized and in most cases aliquots of the entire homogenate were used to assay for total nucleoside diphosphatase (NDPase). Parallel assays were usually run after treating the homogenate with deoxycholate. Both glutaraldehyde and formaldehyde inhibited NDPase activity, the extent of this inhibition depending upon fixation time, fixative concentration and the particular aldehyde used, although with both fixatives inhibition did not increase beyond a certain level even with further increase in fixation time or fixative concentration. With glutaraldehyde and glutaraldehyde-containing fixatives, this level was normally about 74% inhibition while with formaldehyde it was about the level of non-activated NDPase activity and inhibition could be detected only after deoxycholate treatment. Lead did not appear to inhibit the "fixed" NDPase.

scholarly journals Effects of Maytenus ilicifolia Mart. and Bauhinia candicans Benth infusions on onion root-tip and rat bone-marrow cells

2002 ◽  
Vol 25 (1) ◽  
pp. 85-89 ◽  
Author(s):  
Marjori Leiva Camparoto ◽  
Rosangela de Oliveira Teixeira ◽  
Mário Sérgio Mantovani ◽  
Veronica Elisa Pimenta Vicentini
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Root Tip ◽  
Onion Root ◽  
Maytenus Ilicifolia ◽  
Rat Bone ◽  
Marrow Cells

Erratum: Making the Most of Onion Root Tip Mitosis

1982 ◽  
Vol 44 (2) ◽  
pp. 127-127
Author(s):  
Marshall D. Sundberg
Keyword(s):  
Root Tip ◽  
Onion Root
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