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111.
Proteomic changes in maize roots after short-term adjustment to saline growth conditions 总被引:2,自引:0,他引:2
It is of fundamental importance to understand adaptation processes leading to salt resistance. The initial effects on maize roots in the first hour after the adjustment to saline conditions were monitored to elucidate initial responses. The subsequent proteome change was monitored using a 2‐D proteomic approach. We found several new salt‐inducible proteins, whose expression has not been previously reported to be modulated by salt. A set of phosphoproteins in maize was detected but only ten proteins were phosphorylated and six proteins were dephosphorylated after the application of 25 mM NaCl for 1 h. Some of the phosphorylated maize proteins such as fructokinase, UDP‐glucosyl transferase BX9, and 2‐Cys‐peroxyredoxine were enhanced, whereas an isocitrate‐dehydrogenase, calmodulin, maturase, and a 40‐S‐ribosomal protein were dephosphorylated after adjustment to saline conditions. The initial reaction of the proteome and phosphoproteome of maize after adjustment to saline conditions reveals members of sugar signalling and cell signalling pathways such as calmodulin, and gave hint to a transduction chain which is involved in NaCl‐induced signalling. An alteration of 14‐3‐3 proteins as detected may change plasma membrane ATPase activity and cell wall growth regulators such as xyloglucane endotransglycosylase were also found to be changed immediately after the adjustment to salt stress. 相似文献
112.
113.
Wnt和MAPK信号通路在生物进化过程中高度保守,参与调控胚胎发育和细胞增殖、分化及凋亡等。Wnt和MAPK信号通路调控失常可导致胚胎发育异常和肿瘤形成。近年来发现这两条信号通路在肿瘤发生发展中存在着大量串话(crosstalk),彼此之间相互调节,共同发挥促癌或抑癌作用,因此,更好地了解两条通路是如何在肿瘤形成中发生交叉对话对于将来肿瘤治疗非常有价值。 相似文献
114.
1. In lentic freshwater habitats, the composition of animal assemblages shifts along a gradient from temporary to permanent basins. When habitats with different degrees of permanence are at the scale of the home range of species, they constitute alternatives in terms of energy acquisition through feeding. 2. In this context, previous studies showed an advantage of metamorphic over paedomorphic tiger salamanders (Ambystoma tigrinum) in temporary ponds which are only available to metamorphs. The aim of this study was to establish whether salamanders obtain similar benefits in ponds that do not differ in water permanence and whether salamanders shifted from detrimental to advantageous ponds. To this end, we determined the feeding habits, body condition and movement patterns of the two morphs in a complex of four permanent and four temporary ponds. 3. Consistent with previous studies, metamorphs consumed higher‐quality diets than paedomorphs in term of energy intake. However, these differences occurred because metamorphs consumed fairy shrimp in a single temporary pond. Individual movement patterns confirmed that most of the metamorphs used different aquatic habitats both within and between years and that most of them moved from permanent ponds for breeding towards the most profitable temporary pond in terms of foraging. 4. These results indicate that habitat selection by salamanders is optimal in term of energy intake in metamorphs that use high quality ponds independently of hydroperiod. It seems that both spatial and temporal variation can influence the relative foraging success of each morph. 相似文献
115.
I. A. Vladimirova I. B. Filippov E. M. Kulieva Yu. B. Dyskina V. Ya. Ganitkevich 《Neurophysiology》2007,39(1):20-28
Our studies of the role of phospholipase C in inhibitory synaptic action upon visceral smooth muscles demonstrated that, under
conditions of carbachol (CCh)-induced pre-activation of cholinoreceptors, ATP-or noradrenaline (NA)-evoked relaxation of these
muscles is mediated by the phospholipase C-independent pathway, while the phospholipase C-dependent pathway does not manifest
itself as a mechanism that determines the inhibitory effect of the above transmitters. Under conditions of pre-activation
of muscarinic cholinoreceptors, ATP-and NA-induced relaxation is continued due to activation of inositol trisphosphate (InsP3)-sensitive receptors despite the fact that the pathway of inhibition is phospholipase C-independent. This is confirmed by
complete depression of the inhibitory effects of ATP and NA against the background of CCh-induced contraction after pre-incubation
of the studied preparations together with 100 μM 2-APB, a blocker of InsP3 receptors. Selective blockings of either M2 or M3 cholinoreceptors are accompanied by a complete loss of the ability of the above blocker of InsP3 receptors (2-APB) to suppress ATP-and NA-induced contraction of smooth muscles in the state of CCh-induced contraction. It
can be hypothesized that, under conditions of selective pre-activation of M2 or M3 cholinoreceptors, the mechanisms of intracellular signalling mediating the inhibition events are modified. The InsP3-dependent pathway that determines both adrenergic and purinergic inhibition of smooth muscles is switched off, and the inhibitory
action of neurotransmitters is realized under such conditions through the InsP3-independent pathway. Therefore, in our study we first found differences between cellular mechanisms underlying ATP-and NA-induced
inhibition of smooth muscles under conditions of selective activation of either M2 or M3 cholinoreceptors and the mechanisms underlying the relaxing action of inhibitory neurotransmitters under conditions of combined
synergistic activation of cholinoreceptors of both the above-mentioned subtypes.
Neirofiziologiya/Neurophysiology, Vol. 39, No. 1, pp. 22–31, January–February, 2007. 相似文献
116.
Nangia-Makker P Nakahara S Hogan V Raz A 《Journal of bioenergetics and biomembranes》2007,39(1):79-84
During the past decade, extensive progress has been made toward understanding the molecular basis for the regulation of apoptosis.
In mammalian cells undergoing apoptosis, two distinct mechanisms or pathways are operated and are triggered by cell death
stimuli from intra- or extra-cellular environments, namely the intrinsic or extrinsic pathways, resulting in mitochondrial
membrane depolarization. Several lines of evidence from our laboratories and others have indicated that galectin-3 plays an
important role in these pathways by binding to various ligands. Here the authors provide a brief discussion on the role of
endogenous or extra-cellular galectin-3 in the regulation of apoptosis and how it could be used as a therapeutic target using
natural plant products as its functional inhibitors. 相似文献
117.
Biosynthesis,accumulation and emission of carotenoids, α-tocopherol,plastoquinone, and isoprene in leaves under high photosynthetic irradiance 总被引:1,自引:0,他引:1
Lichtenthaler HK 《Photosynthesis research》2007,92(2):163-179
The localization of isoprenoid lipids in chloroplasts, the accumulation of particular isoprenoids under high irradiance conditions, and channelling of photosynthetically fixed carbon into plastidic thylakoid isoprenoids, volatile isoprenoids, and cytosolic sterols are reviewed. During leaf and chloroplast development in spring plastidic isoprenoid biosynthesis provides primarily thylakoid carotenoids, the phytyl side-chain of chlorophylls and the electron carriers phylloquinone K1, alpha-tocoquinone and alpha-tocopherol, as well as the nona-prenyl side-chain of plastoquinone-9. Under high irradiance, plants develop sun leaves and high light (HL) leaves with sun-type chloroplasts that possess, besides higher photosynthetic CO2 assimilation rates, different quantitative levels of pigments and prenylquinones as compared to shade leaves and low light (LL) leaves. After completion of chloroplast thylakoid synthesis plastidic isoprenoid biosynthesis continues at high irradiance conditions, constantly accumulating alpha-tocopherol (alpha-T) and the reduced form of plastoquinone-9 (PQ-9H2) deposited in the steadily enlarging osmiophilic plastoglobuli, the lipid reservoir of the chloroplast stroma. In sun leaves of beech (Fagus) and in 3-year-old sunlit Ficus leaves the level of alpha-T and PQ-9 can exceed that of chlorophyll b. Most plants respond to HL conditions (sun leaves, leaves suddenly lit by the sun) with a 1.4-2-fold increase of xanthophyll cycle carotenoids (violaxanthin, zeaxanthin, neoxanthin), an enhanced operation of the xanthophyll cycle and an increase of beta-carotene levels. This is documented by significantly lower values for the weight ratio chlorophylls to carotenoids (range: 3.6-4.6) as compared to shade and LL leaves (range: 4.8-7.0). Many plant leaves emit under HL and high temperature conditions at high rates the volatile compounds isoprene (broadleaf trees) or methylbutenol (American ponderosa pines), both of which are formed via the plastidic 1-deoxy-D: -xylulose-phosphate/2-C-methylerythritol 5-phosphate (DOXP/MEP) pathway. Other plants by contrast, accumulate particular mono- and diterpenes. Under adequate photosynthetic conditions the chloroplastidic DOXP/MEP isoprenoid pathway essentially contributes, with its C5 isoprenoid precusors, to cytosolic sterol biosynthesis. The possible cross-talk between the two cellular isoprenoid pathways, the acetate/MVA and the DOXP/MEP pathways, that preferentially proceeds in a plastid-to-cytosol direction, is shortly discussed. 相似文献
118.
Wiley PR Tosi P Evrard A Lovegrove A Jones HD Shewry PR 《Plant molecular biology》2007,65(1-2):125-136
Increasing its root to shoot ratio is a plant strategy for restoring water homeostasis in response to the long-term imposition
of mild water stress. In addition to its important role in diverse fundamental processes, indole-3-acetic acid (IAA) is involved
in root growth and development. Recent extensive characterizations of the YUCCA gene family in Arabidopsis and rice have elucidated that member’s function in a tryptophan-dependent IAA biosynthetic pathway. Through forward- and
reverse-genetics screening, we have isolated Tos17 and T-DNA insertional rice mutants in a CONSTITUTIVELY WILTED1 (COW1) gene, which encodes a new member of the YUCCA protein family. Homozygous plants with either a Tos17 or T-DNA-inserted allele of OsCOW1 exhibit phenotypes of rolled leaves, reduced leaf widths, and lower root to shoot ratios. These phenotypes are evident in
seedlings as early as 7–10 d after germination, and remain until maturity. When oscow1 seedlings are grown under low-intensity light and high relative humidity, the rolled-leaf phenotype is greatly alleviated.
For comparison, in such conditions, the transpiration rate for WT leaves decreases approx. 5- to 10-fold, implying that this
mutant trait results from wilting rather than being a morphogenic defect. Furthermore, a lower turgor potential and transpiration
rate in their mature leaves indicates that oscow1 plants are water-deficient, due to insufficient water uptake that possibly stems from that diminished root to shoot ratio.
Thus, our observations suggest that OsCOW1-mediated IAA biosynthesis plays an important role in maintaining root to shoot ratios and, in turn, affects water homeostasis
in rice. 相似文献
119.
Esmaeil Ebrahimie Mohammad Reza Naghavi Abdolhadi Hosseinzadeh Mohammad Reza Behamta Manijeh Mohammadi-Dehcheshmeh Ahmad Sarrafi German Spangenberg 《Plant Cell, Tissue and Organ Culture》2007,90(3):293-311
In this study, using cumin embryo as explant and manipulating plant growth regulators (PGRs) in regeneration medium, the main
in vitro morphogenesis pathways including direct shoot organogenesis, direct somatic embryogenesis, indirect somatic embryogenesis,
and indirect shoot organogenesis were obtained. The effects of PGRs, subculture, and light on the induction and progression
of different pathways were studied in detail. Direct shoot organogenesis occurred on the meristematic zone, while direct somatic
embryogenesis was observed on hypocotyl part of cumin embryo (more differentiated part). Application of BAP (0.1 mgl−1) was the sole triggering factor for induction of callus and indirect regeneration pathways. Exogenous IAA played the central
role in the direct somatic embryogenesis pathway; however, the combined effects of IAA and NAA along with the high endogenous
cytokinin level resulted in direct shoot organogenesis. Subculturing revealed accelerating effects on direct somatic embryogenesis
pathway and callus formation. Conversely, subculturing had negative effect on direct shoot organogenesis pathway. In certain
combinations of PGRs, like 0.4 mgl−1 IAA + 0.4 mgl−1 NAA, co-induction and co-regeneration of different pathways were observed. Investigation of genotype dependencies of different
pathways showed that direct pathways are more genotype-dependent, stable, and faster than indirect pathways. This research
presents the embryo of cumin as a convenient model material for induction and comparison of different morphogenesis pathways. 相似文献
120.
Induced systemic resistance (ISR) in plants: mechanism of action 总被引:1,自引:0,他引:1
Plants possess a range of active defense apparatuses that can be actively expressed in response to biotic stresses (pathogens
and parasites) of various scales (ranging from microscopic viruses to phytophagous insect). The timing of this defense response
is critical and reflects on the difference between coping and succumbing to such biotic challenge of necrotizing pathogens/parasites.
If defense mechanisms are triggered by a stimulus prior to infection by a plant pathogen, disease can be reduced. Induced
resistance is a state of enhanced defensive capacity developed by a plant when appropriately stimulated. Systemic acquired
resistance (SAR) and induced systemic resistance (ISR) are two forms of induced resistance wherein plant defenses are preconditioned
by prior infection or treatment that results in resistance against subsequent challenge by a pathogen or parasite. Selected
strains of plant growth-promoting rhizobacteria (PGPR) suppress diseases by antagonism between the bacteria and soil-borne
pathogens as well as by inducing a systemic resistance in plant against both root and foliar pathogens. Rhizobacteria mediated
ISR resembles that of pathogen induced SAR in that both types of induced resistance render uninfected plant parts more resistant
towards a broad spectrum of plant pathogens. Several rhizobacteria trigger the salicylic acid (SA)-dependent SAR pathway by
producing SA at the root surface whereas other rhizobacteria trigger different signaling pathway independent of SA. The existence
of SA-independent ISR pathway has been studied in Arabidopsis thaliana, which is dependent on jasmonic acid (JA) and ethylene signaling. Specific Pseudomonas strains induce systemic resistance in viz., carnation, cucumber, radish, tobacco, and Arabidopsis, as evidenced by an enhanced defensive capacity upon challenge inoculation. Combination of ISR and SAR can increase protection
against pathogens that are resisted through both pathways besides extended protection to a broader spectrum of pathogens than
ISR/SAR alone. Beside Pseudomonas strains, ISR is conducted by Bacillus spp. wherein published results show that several specific strains of species B. amyloliquifaciens, B. subtilis, B. pasteurii, B. cereus, B. pumilus, B. mycoides, and B.sphaericus elicit significant reduction in the incidence or severity of various diseases on a diversity of hosts. 相似文献