Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “radicle”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1989

Venoocclusive lesions of the central veins and portal vein radicles secondary to intraarterial 5-fluoro-2'-deoxyuridine infusion.

Venoocclusive disease is characterized by the occurrence of occlusive lesions of the central and subhepatic veins, usually involving the liver in a diffuse fashion. We report a case showing venoocclusive lesions of the central veins and the portal vein radicles affecting only a portion of the left lobe of the liver following intraarterial 5-fluoro-2'-deoxyuridine therapy for metastatic adenocarcinoma of the colon. Possible mechanisms and the significance of venoocclusive lesions of portal vein radicles are discussed.

Aged↗
PubMed2002

Antioxidant enzymes and DPPH-radical scavenging activity in chilled and heat-shocked rice (Oryza sativa L.) seedlings radicles.

Chilling whole rice seedlings at 5 degrees C significantly increased the time needed to recover linear growth and reduced the subsequent linear rate of radicle growth. Subjecting nonchilled seedlings to a 45 degrees C heat shock for up to 20 min did not alter subsequent growth, whereas a 3 min heat shock was optimal in reducing growth inhibition caused by 2 days of chilling. The activity of five antioxidant enzymes [superoxide dismutase (EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11), glutathione reductase (GR; EC 1.6.4.2), and guaiacol peroxidase (GPX; EC 1.11.1.7)] and DPPH (1,1-diphenyl-2-picrylhydrazyl)-radical scavenging activity were measured in heat-shocked and/or chilled radicles. Heat shock slightly increased the activity of CAT, APX, and GR and suppressed the increase of GR and GPX activity during recovery from chilling. Increased CAT, APX, GR, and DPPH-radical scavenging activity and protection of CAT activity during chilling appear to be correlated with heat shock-induced chilling tolerance.

Ascorbate Peroxidases↗
PubMed2004

Sucrose regulates elongation of carrot somatic embryo radicles as a signal molecule.

Elongation of carrot somatic embryo radicles was inhibited by sucrose at or above 5% (145 mM). This effect would not be released until the sucrose concentration was lowered again. Morphological and cytological studies as well as determination of ABA content and analysis of the expression mode of a Lea gene, all point to its similarity to natural dormancy and germination of seeds. Use of monosaccharides (glucose and fructose), other disaccharide (maltose), and isomolar concentration of osmotica (mannitol and sorbitol), did not show similar regulatory effect. It is thus clear that the regulatory effect is not a result of simple osmotic stress. Hexokinase inhibitors such as glucosamine and N -acetyl-glucosamine did not exert any influence on the regulation-deregulation effects of sucrose. Mannose, which inhibits germination of Arabidopsis seeds, did not prevent carrot somatic embryo radicles from elongating. It is thus inferred that this sucrose-signaling pathway may be independent of hexokinase. As a first step to understand the molecular mechanism of this process, a carrot sucrose transporter gene ( cSUT ) expressed in the embryos and roots specifically was isolated. Studies on transformed yeast mutant with cSUT cDNA identified its sucrose transport activity. Northern hybridization and gel retardation experiment revealed that there is a marked increase in expression of cSUT at the beginning of somatic embryo germination, and this is attributed to regulation on the level of transcription. This suggested the possibility that cSUT has an important role in this sucrose signal regulation system.

Abscisic Acid↗
PubMed1997

Galactorrhoea and amenorrhoea due to an intradural neurinoma originating from a thoracic intercostal nerve radicle.

A 42-year-old woman had galactorrhoea and amenorrhoea. Four years previously she complained of sensory disturbance of her legs, with galt disturbance. Serum PRL level was 1408 mU/l. Magnetic resonance imaging showed a spindle-shaped mass in the spinal canal at the level of the ninth thoracic vertebra. The tumour was removed and histologically was found to be a neurinoma originating from the right ninth intercostal nerve radicle. Soon after the operation, galactorrhoea, amenorrhoea and neurological symptoms disappeared. Prolactin levels normalized at 346 mU/l. These findings indicate that hyperprolactinaemia occurred as a result of the stimulation of afferent fibres from an intercostal nerve in a patient with intradural neurinoma of the intercostal nerve radicle.

Adult↗
PubMed2002

Peroxidase activity develops in the micropylar endosperm of tomato seeds prior to radicle protrusion.

Peroxidase activity developed specifically in the micropylar region of the endosperm of imbibed tomato seeds prior to radicle emergence. The activity was first detected approximately 24 h after the start of imibibition (6 h before radicle emergence) and increased markedly thereafter. In the lateral portion of the endosperm, peroxidase activity was undetectable for the first 2 d after the start of imbibition. Although the activity in the lateral endosperm became detectable 3 d after imbibition, the extent of the development of the activity was slight. The localization of peroxidase activity in the micropylar endosperm 2 d after the start of imbibition was confirmed by tissue printing analyses. When the endosperm tissues were wounded, there was an enhancement of the enzyme activity at the wounded region. H2O2 was formed at the expense of NADH only in the presence of Mn2+ and dinitrophenol by the extract from the micropylar endosperm in which peroxidase activity was present. The presence of H2O2 in the micropylar portion of the endosperm was shown histochemically. The possible functions of the peroxidases that develop in the endosperm of tomato seeds are discussed.

Enzyme Activation↗
PubMed2000

Cell division and subsequent radicle protrusion in tomato seeds are inhibited by osmotic stress but DNA synthesis and formation of microtubular cytoskeleton are not.

We studied cell cycle events in embryos of tomato (Lycopersicon esculentum Mill. cv Moneymaker) seeds during imbibition in water and during osmoconditioning ("priming") using both quantitative and cytological analysis of DNA synthesis and beta-tubulin accumulation. Most embryonic nuclei of dry, untreated control seeds were arrested in the G(1) phase of the cell cycle. This indicated the absence of DNA synthesis (the S-phase), as confirmed by the absence of bromodeoxyuridine incorporation. In addition, beta-tubulin was not detected on western blots and microtubules were not present. During imbibition in water, DNA synthesis was activated in the radicle tip and then spread toward the cotyledons, resulting in an increase in the number of nuclei in G(2). Concomitantly, beta-tubulin accumulated and was assembled into microtubular cytoskeleton networks. Both of these cell cycle events preceded cell expansion and division and subsequent growth of the radicle through the seed coat. The activation of DNA synthesis and the formation of microtubular cytoskeleton networks were also observed throughout the embryo when seeds were osmoconditioned. However, this pre-activation of the cell cycle appeared to become arrested in the G(2) phase since no mitosis was observed. The pre-activation of cell cycle events in osmoconditioned seeds appeared to be correlated with enhanced germination performance during re-imbibition in water.

Cell Division↗
PubMed1990

Changes in the Endosperm Cell Walls of Two Datura Species before Radicle Protrusion.

The possibility of an association between changes in cell walls of the micropylar portion of the endosperm and the induction of germination was explored in seeds of Datura ferox and Datura stramonium. The structure of the inner surface of the endosperm was studied by scanning electron microscopy and the composition of cell wall polysaccharides analyzed by gas chromatography and gas chromatography-mass spectrometry. Both scanning electron microscope images and chemical analysis showed changes in the micropylar portion of the endosperm in induced seeds before radicle protrusion. The inner surface of the endosperm appeared eroded, and in some areas, wall material seemed to be missing. The content of the main component of the cell wall polysaccharides, containing predominantly 4-linked mannose, decreased well before the emergence of the radicle through the endosperm. We propose that the degradation of a mannan type polysaccharide is an important factor in the reduction in mechanical strength of the endosperm, thus facilitating germination.

Journal Article↗
PubMed2004

Effect of acetaldehyde, arsenite, ethanol, and heat shock on protein synthesis and chilling sensitivity of cucumber radicles.

Exposure to a chilling temperature of 2.5 degrees C for 96 h inhibited the subsequent growth of cucumber seedling radicles at 25 degrees C by 92%. Exposing seedling with 5 +/- 1 mm long radicles to acetaldehyde vapour (275 micro l l(-1)) or to an aqueous ethanol solution (0.6 M) for 2 h, or to 45 degrees C for 10 min before chilling, increased chilling tolerance so that the chilling treatment reduced growth by only 47, 39 or 36%, respectively. All of these effective treatments induced the synthesis of a number of proteins, and suppressed de novo protein synthesis (i.e. the incorporation of [(35)S]-methionine) by about 70%. In contrast, treatment for 2 h with an aqueous arsenite solution (100 micro M) had no effect on chilling sensitivity or the incorporation of [(35)S]-methionine, yet it induced the synthesis of a complement of proteins that were similar to that induced by the effective heat-shock treatment. A unique protein or set of proteins may be responsible for heat-shock-induced chilling tolerance, but none was detected. The ability of various abiotic stresses to suppress protein synthesis may be more important in increasing tolerance to chilling injury than their ability to induce the synthesis of specific proteins.

Journal Article↗
PubMed2001

The alkaline single-cell gel electrophoresis/comet assay: a way to study DNA repair in radicle cells of germinating Vicia faba.

Dry seeds are known to accumulate DNA damage with time of storage. Repair of DNA lesions during germination of Vicia faba seeds was followed in the radicles using the alkaline single-cell gel electrophoresis/comet assay. In this assay nuclei were liberated, mixed with agarose and spread out over a microscope slide. After lysis of the nuclear membrane and unwinding of the DNA duplex, DNA was stretched during electrophoresis, giving a comet-like migration pattern. The more DNA was damaged, the higher its mobility. DNA repair took place rapidly the first hours of imbibition and more slowly until ca 33 h after onset of germination. A small amount of heavily damaged cells remained present. Labelling with BrdU provided the possibility to localize repair patches and replicated sites in the comet migration pattern. At 15 h of germination, incorporation of BrdU in radicle DNA was situated at random over the entire comet. At 33 h, DNA repair was more or less accomplished and BrdU was mainly localized in the 'heads' of most comets.

Bromodeoxyuridine↗
PubMed2005

HVEGF165 increases survival of transplanted hepatocytes within portal radicles: suggested mechanism for early cell engraftment.

VEGF is a potent angiogenic factor that promotes hepatocyte growth, increases permeability of blood vessels, and induces vasodilatation, and may accelerate engraftment and function of transplanted hepatocytes. The aim was to study the effect of VEGF on early hepatocyte engraftment. Thirty-two Lewis syngeneic female rats underwent 70% partial hepatectomy. Eighteen received 240 ng VEGF165 and 14 received saline for control. Thereafter, intrasplenic transplantation of 10(7) male hepatocytes was done. Semiquantitative analysis of PCR product of the SRY region of the Y-chromosome was performed. Paraffin-embedded sections were stained for H&E and for PCNA immunostaining. By PCR, male hepatocytes were identified in 8 livers out of 14 VEGF-treated rats at 24-48 h, compared with only 1 liver out of 8 controls. Transplanted cells were seen within portal vessels radicles in 7 out of 14 VEGF-treated rats for as long as 48 h posttransplantation, compared with only one control liver at 24 h. There was no histological sign of cell injury to transplanted or adjacent cells. Two weeks after transplantation male transplanted cells were identified in two out of four rats treated with hVEGF165 and in one out of six rats treated with saline. No transplanted cells were detected within portal tracts 14 days after transplantation. hVEGF165 enhances the presence of transplanted hepatocytes within portal vessels after transplantation. We suggest an additional mechanism for cell engraftment, whereby transplanted hepatocytes first stick to each other in the portal radicles. Later they become included in the liver parenchyma as groups of organized cells in a process stimulated by VEGF.

Angiogenesis Inducing Agents↗
PubMed1976

Mechanism of nuclear DNA replication in radicles of germinating cotton.

The mechanism of nuclear DNA replication in radicles of germinating cotton (Gossypium barbadense) was investigated. Pulse-labeling with [(3)H]thymidine indicates that replication intermediates are of small molecular weight (4-10S) and behave as if single-stranded. Prolonged labeling indicates that intermediates are of discrete size, suggesting a mechanism of discontinuous replication. Electron microscopy of nuclear DNA demonstrates a complex architecture which may include "eye forms" and "forks" similar to those reported in prokaryotes and animal systems. The possible universality of DNA replication mechanisms is discussed.

Journal Article↗
PubMed1976

Induction by gamma-radiation of DNA synthesis in radicle cells of germinating seeds of Pisum sativum l.

In radicle meristem cells of germinating seeds of the pea (Pisum sativum L) before the onset of replicative synthesis of DNA, irradiation with 2-3 krad of gamma-rays induced the incorporation of 3H-thymidine (3H-TdR). Maximum isotope incorporation was noted during the first 2 hours after irradiation. Higher doses of radiation suppressed 3H-TdR incorporation. It was not seen after gamma-irradiation of air-dried seeds, nor after fast-neutron irradiation. The replication inhibitors hydroxyurea and 5-aminouracil had no effect on the gamma-induced incorporation of 3H-TdR, Whereas caffeine and acriflavine inhibited it to some extent. It is suggested that the gamma-radiation-induced incorporation of 3H-TdR in meristem cells during the pre-replicative period may be connected with repair phenomena.

Acriflavine↗
PubMed1970

Ultrastructural changes in cells of pea embryo radicles during germination.

Radicles (1 mm long) of pea embryo axes, excised from dormant seeds and from seeds soaked for 80 min, 8, 12, and 48 hr, were fixed in glutaraldehyde and postfixed in OsO(4). The nucleus was only slightly changed by 48 hr soaking, but cytoplasmic organelles underwent developmental changes. There was proliferation of endoplasmic reticulum, the appearance of dictyosomes, and an inward migration of lipid bodies. Most of these changes were observed within 8 hr after soaking started. Plastids, mitochondria, protein bodies, and protein crystalline bodies were also identified and their developmental changes were followed.

Cell Membrane↗
PubMed2003

Expression of a GALACTINOL SYNTHASE gene in tomato seeds is up-regulated before maturation desiccation and again after imbibition whenever radicle protrusion is prevented.

Raffinose family oligosaccharides (RFOs) have been implicated in mitigating the effects of environmental stresses on plants. In seeds, proposed roles for RFOs include protecting cellular integrity during desiccation and/or imbibition, extending longevity in the dehydrated state, and providing substrates for energy generation during germination. A gene encoding galactinol synthase (GOLS), the first committed enzyme in the biosynthesis of RFOs, was cloned from tomato (Lycopersicon esculentum Mill. cv Moneymaker) seeds, and its expression was characterized in tomato seeds and seedlings. GOLS (LeGOLS-1) mRNA accumulated in developing tomato seeds concomitant with maximum dry weight deposition and the acquisition of desiccation tolerance. LeGOLS-1 mRNA was present in mature, desiccated seeds but declined within 8 h of imbibition in wild-type seeds. However, LeGOLS-1 mRNA accumulated again in imbibed seeds prevented from completing germination by dormancy or water deficit. Gibberellin-deficient (gib-1) seeds maintained LeGOLS-1 mRNA amounts after imbibition unless supplied with gibberellin, whereas abscisic acid (ABA) did not prevent the loss of LeGOLS-1 mRNA from wild-type seeds. The presence of LeGOLS-1 mRNA in ABA-deficient (sitiens) tomato seeds indicated that wild-type amounts of ABA are not necessary for its accumulation during seed development. In all cases, LeGOLS-1 mRNA was most prevalent in the radicle tip. LeGOLS-1 mRNA accumulation was induced by dehydration but not by cold in germinating seeds, whereas both stresses induced LeGOLS-1 mRNA accumulation in seedling leaves. The physiological implications of LeGOLS-1 expression patterns in seeds and leaves are discussed in light of the hypothesized role of RFOs in plant stress tolerance.

Abscisic Acid↗
PubMed1996

An Endo-[beta]-Mannanase Develops Exclusively in the Micropylar Endosperm of Tomato Seeds Prior to Radicle Emergence.

A galactomannan-hydrolyzing enzyme that develops pregerminatively in the micropylar region of the endosperm of the tomato (Lycopersicon esculentum [L.] Mill.) seed was characterized. The enzyme was endo-[beta]-mannanase (EC 3.2.1.78), since it hydrolyzed galactomannan into oligosaccharides with no release of galactose and mannose. The mobility of this pregerminative enzyme in sodium dodecyl sulfate and native polyacrylamide gel electrophoresis was not identical to that of any of the three endo-[beta]-mannanases that develop in the same tissue (endosperm) after germination (H. Nonogaki, M. Nomaguchi, Y. Morohashi [1995] Physiol Plant 94: 328-334). There were also some differences in the products of galactomannan hydrolysis between the pregerminative and the postgerminative enzymes, indicating that the action pattern is different between the two types of enzymes. The pregerminative enzyme began to develop in the micropylar region of the endosperm at about 18 h postimbibition and increased up to the time immediately before radicle protrusion (24 h postimbibition). This enzyme was not present in the lateral part of the endosperm at any stage before or after germination. It is proposed that the enzyme develops prior to germination specifically at the micropylar region of the endosperm.

Journal Article↗
PubMed2000

Abscisic acid inhibition of radicle emergence but not seedling growth is suppressed by sugars.

Low concentrations of sugars altered the sensitivity of seed germination to inhibition by exogenous abscisic acid (ABA). Germination of wild-type and ABA-insensitive (abi) Arabidopsis seeds was assayed on media containing ABA and a variety of sugars and sugar alcohols. The inhibitory effects of ABA were strongly repressed in the presence of 15 to 90 mM glucose (Glc), sucrose, or fructose, but not by comparable concentrations of sorbitol or mannitol. Several features of the response to Glc are inconsistent with a purely nutritional effect: The optimal sugar concentration is low and differs between the wild type and the abi mutants. Furthermore, Glc suppression of ABA inhibition is light dependent and limited to the process of radicle emergence.

Abscisic Acid↗
PubMed1970

Stimulation of Solute Loss from Radicles of Gossypium hirsutum L. by Chilling, Anaerobiosis, and Low pH.

The loss of organic substances from cotton (Gossypium hirsutum L.) radicles is enhanced by chilling, low pH, or anaerobic conditions. Solute loss returns to a low level when the stimulus is removed, indicating no permanent injury to membranes. Loss of solute induced by chilling or anaerobiosis is reversed or prevented by calcium or magnesium. These cations did not reduce the solute loss resulting from low pH. The site of loss appears to be localized at or near the root tip. If the seedling cotyledons are removed, the loss is greatly reduced, indicating the need for a reserve pool of organic substances.

Journal Article↗