Investigation of the mechanism underlying the inhibitory effect of heterologous ras genes in plant cells

1993 ◽  
Vol 22 (5) ◽  
pp. 751-765 ◽  
Author(s):  
Zong R. Liu ◽  
John C. Sanford
1979 ◽  
Vol 34 (12) ◽  
pp. 1195-1198 ◽  
Author(s):  
C. Cocito ◽  
O. Tiboni ◽  
F. Vanlinden ◽  
O. Ciferri

Abstract The light-driven incorporation of amino acids by isolated spinach chloroplasts is inhibited by the M component (VM) and not by the S component (VS) of virginiamycin. This inhibitory effect is partially reversible. In chloroplast extracts, poly(U)-directed polyphenylalanine formation is strongly inhibited by VM and not by VS. The in vivo synergistic effect of VM and VS observed in bacteria and algae, does not occur in isolated chloroplasts and chloroplast extracts.


Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 843
Author(s):  
Elena Bonciu ◽  
Aurel Liviu Olaru ◽  
Elena Rosculete ◽  
Catalin Aurelian Rosculete

This cytogenetic study evaluates the biostimulation potential of the aqueous extract of seabuckthorn fruits (AESF) in plant cells, using the Allium cepa species as a test plant. The effects were monitored both at the macroscopic and microscopically level. The onion bulbs were exposed to the action of different concentrations of AESF (0.5, 1, 1.5, 2, and 2.5%) for 72 h. The obtained results showed the positive effect induced by the aqueous extract on the growth of the meristematic roots, but only at concentrations ranging between 0.5–1.5%, when the average length of the roots had values between 2.51–3.40 cm, which means an increase compared to the untreated control with 3.71–40.49%. Within the same concentration range of the AESF, an effect of intensifying the mitotic activity was recorded. On the other hand, at the 2–2.5% concentration of the AESF, there was an inhibitory effect on the growth of meristematic roots. Additionally, concentrations ≥2% of AESF induced a cytotoxic and genotoxic effect through the occurrence of some chromosomal and nuclear abnormalities in A. cepa cells (sticky, laggards, ring chromosomes, and micronucleus). The obtained results suggest the biostimulation potential of the AESF for plant cells and the possibility of using it as an eco-friendly fertilizer.


2015 ◽  
Vol 10 (5) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Hamako Sasamoto ◽  
Yoshiharu Fujii ◽  
Hiroshi Ashihara

To investigate the ecological role of caffeine, theobromine, theophylline and paraxanthine, which are released from purine alkaloid forming plants, the effects of these purine alkaloids on the division and colony formation of lettuce cells were assessed at concentrations up to 1 mM. Five days after treatment with 500 μM caffeine, theophylline and paraxanthine, division of isolated protoplasts was significantly inhibited. Thirteen days treatment with >250 μM caffeine had a marked inhibitory effect on the colony formation of cells derived from the protoplasts. Other purine alkaloids also acted as inhibitors. The order of the inhibition was caffeine > theophylline > paraxanthine > theobromine. These observations suggest that a relatively low concentration of caffeine is toxic for proliferation of plant cells. In contrast, theobromine is a weak inhibitor of proliferation. Possible allelopathic roles of purine alkaloids in natural ecosystems are discussed.


Author(s):  
G. M. Hutchins ◽  
J. S. Gardner

Cytokinins are plant hormones that play a large and incompletely understood role in the life-cycle of plants. The goal of this study was to determine what roles cytokinins play in the morphological development of wheat. To achieve any real success in altering the development and growth of wheat, the cytokinins must be applied directly to the apical meristem, or spike of the plant. It is in this region that the plant cells are actively undergoing mitosis. Kinetin and Zeatin were the two cytokinins chosen for this experiment. Kinetin is an artificial hormone that was originally extracted from old or heated DNA. Kinetin is easily made from the reaction of adenine and furfuryl alcohol. Zeatin is a naturally occurring hormone found in corn, wheat, and many other plants.Chinese Spring Wheat (Triticum aestivum L.) was used for this experiment. Prior to planting, the seeds were germinated in a moist environment for 72 hours.


Author(s):  
Ann Cleary

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.


Author(s):  
M. Yamada ◽  
K. Ueda ◽  
K. Kuboki ◽  
H. Matsushima ◽  
S. Joens

Use of variable Pressure SEMs is spreading among electron microscopists The variable Pressure SEM does not necessarily require specimen Preparation such as fixation, dehydration, coating, etc which have been required for conventional scanning electron microscopy. The variable Pressure SEM allows operating Pressure of 1˜270 Pa in specimen chamber It does not allow microscopy of water-containing specimens under a saturated vapor Pressure of water. Therefore, it may cause shrink or deformation of water-containing soft specimens such as plant cells due to evaporation of water. A solution to this Problem is to lower the specimen temperature and maintain saturated vapor Pressures of water at low as shown in Fig. 1 On this technique, there is a Published report of experiment to have sufficient signal to noise ratio for scondary electron imaging at a relatively long working distance using an environmental SEM. We report here a new low temperature microscopy of soft Plant cells using a variable Pressure SEM (Hitachi S-225ON).


1992 ◽  
Vol 2 (5) ◽  
pp. 809-813 ◽  
Author(s):  
K Gordon ◽  
J Futterer ◽  
T Hohn

1993 ◽  
Vol 3 (5) ◽  
pp. 637-646 ◽  
Author(s):  
Jian-Kang Zhu ◽  
Jun Shi ◽  
Utpal Singh ◽  
Sarah E. Wyatt ◽  
Ray A. Bressan ◽  
...  

2001 ◽  
Vol 120 (5) ◽  
pp. A176-A176
Author(s):  
P KOPPITZ ◽  
M STORR ◽  
D SAUR ◽  
M KURJAK ◽  
H ALLESCHER

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