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1.
Mirjana Mijatović Jasmina Zdravković Živoslav Marković Aleksa Obradović 《Acta Physiologiae Plantarum》2000,22(3):332-335
In this paper we present the data on the disease intensity of the tomato plants grown in glass and plastic-houses, and in
the open field. The infection was caused by the following viruses: Tomato mosaic virus (ToMV), Tobacco mosaic virus (TMV),
Tomato spotted wilt virus (TSWV), Alfalfa mosaic virus (AMV), Potato virus X (PVX), Potato virus Y (PVY), Tomato black ring
virus (TBRV), Tomato ringspot virus (ToRSV), Tomato aspermy virus (TAV), and Cucumber mosaic virus (CMV). These viruses represented
most frequent tomato pathogens in Serbia.
According to the obtained results, it could be concluded that 92.94% of the tested tomato plants grown in glass and plastic-houses,
and 89.82% grown in the open field were infected by one of the above viruses. Most of the plant samples were infected by two
or more viruses. The most frequent viruses — tomato pathogens in Serbia were ToMV, PVY and TMV. 相似文献
2.
The genomic sequences of several RNA plant viruses including cucumber mosaic virus, brome mosaic virus, alfalfa mosaic virus
and tobacco mosaic virus have become available recently. The former two viruses are icosahedral while the latter two are bullet
and rod shaped, respectively in particle morphology. The non-structural 3a proteins of cucumber mosaic virus and brome mosaic
virus have an amino acid sequence homology of 35% and hence are evolutionarily related. In contrast, the coat proteins exhibit
little homology, although the circular dichroism spectrum of these viruses are similar. The non-coding regions of the genome
also exhibit variable but extensive homology. Comparison of the brome mosaic virus and alfalfa mosaic virus sequences reveals
that they are probably related although with a much larger evolutionary distance. The polypeptide folds of the coat protein
of three biologically distinct isometric plant viruses, tomato Bushy stunt virus, southern bean mosaic virus and satellite
tobacco necrosis virus have been shown to display a striking resemblance. All of them consist of a topologically similar 8-standard
β-Barrel. The implications of these studies to the understanding of the evolution of plant viruses will be discussed. 相似文献
3.
Programmed cell death: similarities and differences in animals and plants. A flower paradigm 总被引:1,自引:0,他引:1
Summary. After an overview of the criteria for the definition of cell death in the animal cell and of its different types of death,
a comparative analysis of PCD in the plant cell is reported. The cytological characteristics of the plant cell undergoing
PCD are described.
The role of plant hormones and growth factors in the regulation of this event is discussed with particular emphasis on PCD
activation or prevention by polyamine treatment (doses, timing and developmental stage of the organism) in a Developmental
cell death plant model: the Nicotiana tabacum (tobacco) flower corolla. Some of the effects of polyamines might be mediated by transglutaminase catalysis. The activity
of this enzyme was examined in different parts of the corolla during its life span showing an acropetal trend parallel to
the cell death wave. The location of transglutaminase in some sub-cellular compartments suggests that it exerts different
functions in the corolla DCD. 相似文献
4.
Polyamines and abiotic stress: recent advances 总被引:8,自引:0,他引:8
Summary. In this review we will concentrate in the results published the last years regarding the involvement of polyamines in the
plant responses to abiotic stresses, most remarkably on salt and drought stress. We will also turn to other types of abiotic
stresses, less studied in relation to polyamine metabolism, such as mineral deficiencies, chilling, wounding, heavy metals,
UV, ozone and paraquat, where polyamine metabolism is also modified.
There is a great amount of data demonstrating that under many types of abiotic stresses, an accumulation of the three main
polyamines putrescine, spermidine and spermine does occur. However, there are still many doubts concerning the role that polyamines
play in stress tolerance. Several environmental challenges (osmotic stress, salinity, ozone, UV) are shown to induce ADC activity
more than ODC. The rise in Put is mainly attributed to the increase in ADC activity as a consequence of the activation of
ADC genes and their mRNA levels. On the other hand, free radicals are now accepted as important mediators of tissue injury
and cell death. The polycationic nature of polyamines, positively charged at physiological pH, has attracted the attention
of researchers and has led to the hypothesis that polyamines could affect physiological systems by binding to anionic sites,
such as those associated with nucleic acids and membrane phospholipids. These amines, involved with the control of numerous
cellular functions, including free radical scavenger and antioxidant activity, have been found to confer protection from abiotic
stresses but their mode of action is not fully understood yet. In this review, we will also summarize information about the
involvement of polyamines as antioxidants against the potential abiotic stress-derived oxidative damage.
Authors’ address: Dr. María Patricia Benavides, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956,
Buenos Aires 1113, Argentina 相似文献
5.
Summary. The aim of this study was to investigate the enhancing effect of polyamines on intestinal absorption of fluorescein isothiocyanate-labeled
dextran (MW 4400, FD-4) in the in situ loop study and in vivo oral absorption study. Absorption of FD-4 from the jejunum was
significantly enhanced by 5 mM spermine without serious membrane damage in the jejunum. An in vivo oral absorption study was
also performed, and plasma FD-4 levels increased significantly after co-administration of 30 mM spermine. In the in vitro
transport studies with Caco-2 cells, prolonged incubation with spermine resulted in a gradual decrease in transepithelial
electrical resistance. This finding suggests that the absorption-enhancing mechanism of spermine partly includes opening the
tight junctions of the epithelium via the paracellular route. These results indicate that excess oral ingestion of polyamines
may have widespread health effects via the modulation of the intestinal epithelial barrier function. 相似文献
6.
Summary. Ornithine decarboxylase (ODC) and diamine oxidase (DAO) are important enzymes involved in the metabolism of polyamines (putrescine,
spermidine and spermine). The influence of testosterone (T) and 17, β– estradiol (E2) on the activity of ODC and DAO was examined in cultivated normal rat kidney (NRK) epithelial cells. The results showed an
increase in enzyme activities 4 hours or 12 hours after hormonal treatment. Both T and E2 led to a significant increase (1.6-fold) in ODC protein level as compared to the controls. Cellular concentration of spermidine
and spermine increased (2.2- and 2.6-fold respectively) 4 hours after T addition. A higher levels in concentrations of putrescine
(1.4-fold) and spermine (1.5-fold) 12 hours after E2 treatment were observed. These results suggest that the biosynthesis and terminal oxidation of the polyamines in NRK epithelial
cells are androgen- and estrogen-mediated and depend on the hormonal sensitivity of the cells.
Received April 5, 1999, Accepted December 20, 1999 相似文献
7.
Nikolic J Stojanovic I Pavlovic R Sokolovic D Bjelakovic G Beninati S 《Amino acids》2007,32(1):127-131
Summary. The existing interrelation in metabolic pathways of L-arginine to polyamines, nitric oxide (NO) and urea synthesis could be
affected in sepsis, inflammation, intoxication and other conditions. The role of polyamines and NO in the toxic effect of
mercury chloride on rat liver function was studied. Administration of mercury chloride for 24 h led to significantly elevated
plasma activities of Alanine transaminase (ALT) and Aspartate transaminase (AST). Malondyaldehyde (MDA) levels were unaffected
(p > 0.05) and arginase activity was significantly decreased (p < 0.05) while nitrate/nitrite production was significantly
elevated (p < 0.001) in liver tissue. Polyamine oxidase (PAO) and diamine oxidase (DAO) activities, enzymes involved in catabolism
of polyamines, were decreased. L-arginine supplementation to intoxicated rats potentiated the effect of mercury chloride on
NO production and it was ineffective on arginase activity.
Results obtained in this study show that mercury chloride-induced toxicity leads to abnormally high levels of ALT and AST
that may indicate liver damage with the involvement of polyamine catabolic enzymes and NO. 相似文献
8.
Role of extensin peroxidase in tomato (Lycopersicon esculentum Mill.) seedling growth 总被引:3,自引:0,他引:3
It is proposed that inhibition of extensin peroxidase activity leads to a less rigid cell wall and thus promotes cell expansion
and plant growth. A low-molecular-weight inhibitor derived from the cell walls of suspension-cultured tomato cells was found
to completely inhibit extensin peroxidase-mediated extensin cross-linking in vitro at a concentration of 260 μg/ml. The inhibitor
had no effect upon guaiacol oxidation catalyzed by extensin peroxidase or horseradish peroxidase. We have demonstrated that
the light-irradiated inhibition of plant growth may be partially offset by inhibition of endogenous extensin peroxidase activity.
Overall plant growth was enhanced by up to 15% in the presence of inhibitor relative to control plants. Inhibitor-treated
and illuminated tomato hypocotyls grew up to 15% taller than untreated controls. The inhibitor had no effect upon etiolated
plants over a 15-d period, suggesting that only low levels of peroxidase-mediated cross-linking can be found in the cell walls
of etiolated plants. SDS-PAGE/Western blots of ionically bound protein from both etiolated and illuminated hypocotyls identified
a doublet at 57/58.5 kDa which is immuno-reactive with antibodies raised to tomato extensin peroxidase. Levels of the 58.5-kDa
protein, determined by SDS-PAGE, were at least threefold higher in illuminated tomato hypocotyls than in etiolated hypocotyls.
Three fold higher levels of extensin peroxidase, elevated in-vitro extensin cross-linking activity and 15% higher levels of
cross-linked, non-extractable extensin were observed in illuminated tomato hypocotyls compared with etiolated tomato hypocotyls.
This suggests that white-light inhibition of tomato hypocotyl growth appears to be mediated, at least partially, by deposition
of cell wall extensin, a process regulated by Mr-58,500 extensin peroxidase. Our results indicate that the contribution of peroxidase-mediated extensin deposition to plant
cell wall architecture may have an important role in plant growth.
Received: 22 July 1999 / Accepted: 11 October 1999 相似文献
9.
Agostinelli E Tempera G Molinari A Salvi M Battaglia V Toninello A Arancia G 《Amino acids》2007,33(2):175-187
Summary. In tumours, polyamines and amine oxidases increase as compared to normal tissues. Cytotoxicity induced by bovine serum amine
oxidase (BSAO) and spermine is attributed to H2O2 and aldehydes produced by the reaction. Increasing the incubation temperature from 37 to 42 °C enhances cytotoxicity in cells
exposed to spermine metabolites. The combination BSAO/spermine prevents tumour growth, particularly well if the enzyme has
been conjugated with a biocompatible hydrogel polymer. Since the tumour cells release endogenous substrates of BSAO, the administration
of spermine is not required. Combination with hyperthermia improves the cytocidal effect of polyamines oxidation products.
Our findings show that multidrug resistant (MDR) cells are more sensitive to spermine metabolites than their wild-type counterparts,
due to an increased mitochondrial activity which induces the generation of intracellular ROS prior to the onset of mitochondrial
permeability transition (MPT). It makes this new approach attractive, since the development of MDR is one of the major problems
of conventional cancer therapy. 相似文献
10.
The amino acid sequences of the non-structural protein (molecular weight 35,000; 3a protein) from three plant viruses — cucumber
mosaic, brome mosaic and alfalfa mosaic have been systematically compared using the partial genomic sequences for these three
viruses already available. The 3a protein of cucumber mosaic virus has an amino acid sequence homology of 33.7% with the corresponding
protein of brome mosaic virus. A similar protein from alfalfa mosaic virus has a homology of 18.2% and 14.2% with the protein
from brome mosaic virus and cucumber mosaic virus, respectively. These results suggest that the three plant viruses are evolutionarily
related, although, the evolutionary distance between alfalfa mosaic virus and cucumber mosaic virus or brome mosaic virus
is much larger than the corresponding distance between the latter two viruses. 相似文献
11.
12.
Summary. Glutathione (reduced form GSH and oxidized form GSSG) constitutes an important defense against oxidative stress in the brain,
and taurine is an inhibitory neuromodulator particularly in the developing brain. The effects of GSH and GSSG and glycylglycine,
γ-glutamylcysteine, cysteinylglycine, glycine and cysteine on the release of [3H]taurine evoked by K+-depolarization or the ionotropic glutamate receptor agonists glutamate, kainate, 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionate
(AMPA) and N-methyl-D-aspartate (NMDA) were now studied in slices from the hippocampi from 7-day-old mouse pups in a perfusion system.
All stimulatory agents (50 mM K+, 1 mM glutamate, 0.1 mM kainate, 0.1 mM AMPA and 0.1 mM NMDA) evoked taurine release in a receptor-mediated manner. Both
GSH and GSSG significantly inhibited the release evoked by 50 mM K+. The release induced by AMPA and glutamate was also inhibited, while the kainate-evoked release was significantly activated
by both GSH and GSSG. The NMDA-evoked release proved the most sensitive to modulation: L-Cysteine and glycine enhanced the
release in a concentration-dependent manner, whereas GSH and GSSG were inhibitory at low (0.1 mM) but not at higher (1 or
10 mM) concentrations. The release evoked by 0.1 mM AMPA was inhibited by γ-glutamylcysteine and cysteinylglycine, whereas
glycylglycine had no effect. The 0.1 mM NMDA-evoked release was inhibited by glycylglycine and γ-glutamylcysteine. In turn,
cysteinylglycine inhibited the NMDA-evoked release at 0.1 mM, but was inactive at 1 mM. Glutathione exhibited both enhancing
and attenuating effects on taurine release, depending on the glutathione concentration and on the agonist used. Both glutathione
and taurine act as endogenous neuroprotective effectors during early postnatal life.
Authors’ address: Prof. Simo S. Oja, Brain Research Center, Medical School, FI-33014 University of Tampere, Finland 相似文献
13.
Vereecke D Burssens S Simón-Mateo C Inzé D Van Montagu M Goethals K Jaziri M 《Planta》2000,210(2):241-251
Rhodococcus fascians is a Gram-positive bacterium that infects dicotyledonous and monocotyledonous plants, leading to an alteration in the normal
growth process of the host. The disease results from the modulation of the plant hormone balances, and cytokinins are thought
to play an important role in the induction of symptoms. Generally, on the aerial parts of the plants, existing meristems were
found to be most sensitive to the action of R. fascians, but, depending on the infection procedure, differentiated tissues as well gave rise to shoots. Similarly, in roots not only
actively dividing cells, but also cells with a high competence to divide were strongly affected by R. fascians. The observed symptoms, together with the determined hormone levels in infected plant tissue, suggest that auxins and molecules
of bacterial origin are also involved in leafy gall formation. The complexity of symptom development is furthermore illustrated
by the necessary and continuous presence of the bacteria for symptom persistence. Indeed, elimination of the bacteria from
a leafy gall results in the further development of the multiple embryonic buds of which it consists. This interesting characteristic
offers novel biotechnological applications: a leafy gall can be used for germplasm storage and for plant propagation. The
presented procedure proves to be routinely applicable to a very wide range of plants, encompassing several recalcitrant species.
Received: 14 January 1999 / Accepted: 19 June 1999 相似文献
14.
Summary. Glucocorticoids are potent anti-inflammatory and immunosuppressive agents. As endogenous inhibitors of cytokine synthesis,
glucocorticoids suppress immune activation and uncontrolled overproduction of cytokines, preventing tissue injury. Also, polyamine
spermine is endogenous inhibitor of cytokine production (inhibiting IL-1, IL-6 and TNF synthesis). The idea of our work was
to examine dexamethasone effects on the metabolism of polyamines, spermine, spermidine and putrescine and polyamine oxidase
activity in liver and spleen during sensitization of guinea pigs. Sensitization was done by application of bovine serum albumin
with addition of complete Freund’s adjuvant. Our results indicate that polyamine amounts and polyamine oxidase activity increase
during immunogenesis in liver and spleen. Dexamethasone application to sensitized and unsensitized guinea pigs causes depletion
of polyamines in liver and spleen. Dexamethasone decreases polyamine oxidase activity in liver and spleen of sensitized guinea
pigs, increasing at the same time PAO activity in tissues of unsensitized animals. 相似文献
15.
It is desirable that the expression of transgenes in genetically modified crops is restricted to the tissues requiring the
encoded activity. To this end, we have studied the ability of the heterologous ribulose-1,5-bisphosphate carboxylase/oxygenase
(Rubisco) small-subunit (SSU) gene promoters, RBCS3CP (0.8 kbp) from tomato (hycopersion esculentum Mill.) and SRS1P (1.5 kbp) from soybean (Glycine max [h.] Mers.), to drive expression of the β-glucuronidase (gusA) marker gene in apple (Malus pumila Mill.). Transgenic lines of cultivar Greensleeves were produced by Agrobacterium-mediated transformation and the level of gusA expression in the vegetative tissues of young plants was compared with that produced using the cauliflower mosaic virus (CaMV)
35S promoter. These quantitative GUS data were assessed for their relationship to the copy number of transgene loci. The precise
location of GUS activity in leaves was identified histochemically. The heterologous SSU promoters were active primarily in
the green vegetative tissues of apple, although activity in the roots was noticeably higher with the RBCS3C promoter than with the SRS1 promoter. The mean GUS activity in leaf tissue of the SSU promoter transgenics was approximately half that of plants containing
the CaMV 35S promoter. Histochemical analysis demonstrated that GUS activity was localised to the mesophyll and palisade cells
of the leaf. The influence of light on expression was also determined. The activity of the SRS1 promoter was strictly dependent on light, whereas that of the RBCS3C promoter appeared not to be. Both SSU promoters would be suitable for the expression of transgenes in green photosynthetic
tissues of apple.
Received: 15 June 1999 / Accepted: 12 August 1999 相似文献
16.
Summary. The polyamines are growth factors in both normal and cancer cells. As the intracellular polyamine content correlates positively
with the growth potential of that cell, the idea that depletion of polyamine content will result in inhibition of cell growth
and, particularly tumour cell growth, has been developed over the last 15 years. The polyamine pathway is therefore a target
for development of rationally designed, antiproliferative agents. Following the lessons from the single enzyme inhibitors
(α-difluoromethylornithine DFMO), three generations of polyamine analogues have been synthesised and tested in vitro and in vivo. The analogues are multi-site inhibitors affecting multiple reactions in the pathway and thus prevent the up-regulation of
compensatory reactions that have been the downfall of DFMO in anticancer chemotherapy. Although the initial concept was that
the analogues may provide novel anticancer drugs, it now seems likely that the analogues will have wider applications in diseases
involving hyperplasia. 相似文献
17.
Antizyme and antizyme inhibitor activities influence cellular responses to polyamine analogs 总被引:1,自引:0,他引:1
Summary. Close structural analogs of spermidine and spermine, polyamine mimetics, are potential chemotheraputic agents as they depress
cellular polyamines required for tumor growth. Specific mimetic analogs stimulate synthesis of the regulatory protein antizyme
(AZ), which not only inactivates the initial enzyme in polyamine biosynthesis but also inhibits cellular uptake of polyamines.
The role of AZ induction in influencing cellular uptake of representative analogs was investigated using three analogs produced
by Cellgate Inc., CGC-11047, CGC-11102, and CGC-11144, which exhibit markedly distinct AZ-inducing potential. An inverse correlation
was noted between the AZ-inducing activity of a compound and the steady-state levels accumulated in cells. As some tumor cells
over express AZI as a means of enhancing the polyamines required for aggressive growth, analog sensitivity was examined in
transgenic CHO cells expressing exogenous antizyme inhibitor protein (AZI). Although AZI over expression increased cell sensitivity
to analogs, the degree of this affect varied with the analog used. 相似文献
18.
Summary. The effects of dioxygen on tyrosine hydroxylase (TH) activity was studied, measuring the formation of DOPA from tyrosine,
3H2O from 3,5-3H-tyrosine, or by direct oxygraphic determination of oxygen consumption. A high enzyme activity was observed during the initial
1–2 min of the reactions, followed by a decline in activity, possibly related to a turnover dependent substoichiometrical
oxidation of enzyme bound Fe(II) to the inactive Fe(III) state. During the initial reaction phase, apparent K
m-values of 29–45 μM for dioxygen were determined for all human TH isoforms, i.e. 2–40 times higher than previously reported
for TH isolated from animal tissues. After 8 min incubation, the K
m (O2)-values had declined to an average of 20 ± 4 μM. Thus, TH activity may be severely limited by oxygen availability even at
moderate hypoxic conditions, and the enzyme is rapidly and turnover dependent inactivated at the experimental conditions commonly
employed to measure in vitro activities.
Authors’ address: Jan Haavik, Department of Biomedicine, University of Bergen, 5009 Bergen, Norway 相似文献
19.
Lentini A Provenzano B Caraglia M Shevchenko A Abbruzzese A Beninati S 《Amino acids》2008,34(2):251-256
Summary. Previously published evidences highlighted the effect of transglutaminase (TG, EC 2.3.2.13) activation on the reduction of
the in vitro adhesive and invasive behaviour of murine B16-F10 melanoma cells, as well as in vivo. Here, we investigated the
influence of spermidine (SPD) incorporation by TG into basement membrane components i.e. laminin (LN) or Matrigel (MG), on
the adhesion and invasion of B16-F10 melanoma cells by these TG/SPD-modified substrates. The adhesion assays showed that cell
binding to the TG/SPD-modified LN was reduced by 30%, when compared to untreated LN, whereas the reduction obtained using
TG/SPD-modified MG was 35%. Similarly, tumor cell invasion by the Boyden chamber system through TG/SPD modified LN or MG was
respectively reduced by 45%, and by 69%. Evaluation of matrix metalloproteinase (gelatinases MMP-2 and MMP-9) activities by
gel-zymography showed that MMP-2 activity was unaffected, while MMP-9 activity was reduced by about 32% using TG/SPD-modified
substrate. These results strongly suggest that the observed antiinvasive effect of TG activation in the host may be ascribed
to the covalent incorporation of polyamines, which led to the post-translational modification of some components of the cell
basement membrane. This modification may interfere with the metastatic property of melanoma cells, affecting the proteolytic
activity necessary for their migration and invasion activities.
Authors’ address: Simone Beninati, Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica,
I-00133 Rome, Italy 相似文献
20.
Summary. Gamma-aminobutyric acid (GABA) is considered to be a multifunctional molecule with various physiological effects throughout
the body. It is also evident that the liver contains GABA and its transporter. However, the functions of GABA in liver have
not been well documented. In this study, the cytoprotective effect of GABA against ethanol-induced hepatotoxicity was evaluated
in primary cultured rat hepatocytes. Addition of ethanol induced decrease of cell viability in a dose-dependent manner. However,
treatment with GABA resulted in a dose-dependent recovery from ethanol (150 mM)-induced cytotoxicity.
GABA reversed the ethanol-induced decrease in intracellular polyamine levels. Furthermore, the addition of polyamines also
reversed the ethanol-induced decrease of cell viability. These results suggest that GABA is protective against the cytotoxicity
of ethanol in isolated rat hepatocytes and this effect may be modulated by the maintenance of intracellular polyamine levels. 相似文献