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91.
Ru-Bing Duan Li Zhang Dian-Fu Chen Fan Yang Jin-Shu Yang Wei-Jun Yang 《The Journal of biological chemistry》2014,289(23):16006-16015
There are multiple isoforms of p90 ribosomal S6 kinase (RSK), which regulate diverse cellular functions such as cell growth, proliferation, maturation, and motility. However, the relationship between the structures and functions of RSK isoforms remains undetermined. Artemia is a useful model in which to study cell cycle arrest because these animals undergo prolonged diapauses, a state of obligate dormancy. A novel RSK isoform was identified in Artemia, which was termed Ar-Rsk2. This isoform was compared with an RSK isoform that we previously identified in Artemia, termed Ar-Rsk1. Ar-Rsk2 has an ERK-docking motif, whereas Ar-Rsk1 does not. Western blot analysis revealed that Ar-Rsk1 was activated by phosphorylation, which blocked meiosis in oocytes. Knockdown of Ar-Rsk1 reduced the level of phosphorylated cdc2 and thereby suppressed cytostatic factor activity. This indicates that Ar-Rsk1 regulates the cytostatic factor in meiosis. Expression of Ar-Rsk2 was down-regulated in Artemia cysts in which mitosis was arrested. Knockdown of Ar-Rsk2 resulted in decreased levels of cyclin D3 and phosphorylated histone H3, and the production of pseudo-diapause cysts. This indicates that Ar-Rsk2 regulates mitotic arrest. PLK and ERK RNAi showed that Ar-Rsk2, but not Ar-Rsk1, could be activated by PLK-ERK in Artemia. This is the first study to report that RSK isoforms with and without an ERK-docking motif regulate mitosis and meiosis, respectively. This study provides insight into the relationship between the structures and functions of RSK isoforms. 相似文献
92.
Imbibition conditions and seed dormancy of Arabidopsis thaliana 总被引:2,自引:0,他引:2
The optimal combinations of temperature in the range of 0 to 20°C and duration (1 to 14 days) of imbibition for the induction of germination of Arabidopsis thaliana (L) Heynh., ecotype "Landsberg-erecta", by red light were investigated. At 2°C, 10 days of imbibition are needed tor loss of dormancy, whereas at higher temperatures, e.g 15°C, it is already lost after 1 or 2 days. It is proposed that the development of light-inducible germination is governed by two temperature-dependent processes-the loss of primary or innate dormancy and the simultaneous induction of secondary dormancy. Data are discussed in terms of the availability of phytochrome, the availability of an unknown factor X and changes in sensitivity of the process of germination induction by the far-red absorbing form of phytochrome (Pfr). 相似文献
93.
蝙蝠葛又名北豆根(Menispermum dauricum DC.),为防己科植物,木质落叶缠绕藤本。根和茎供药用。近年临床应用于治疗扁桃体炎、咽喉炎,也可治疗慢性气管炎。用蝙蝠葛制成北豆根片,载入1977年出版的《中华人民共和国- 相似文献
94.
95.
Effects on seed germination of temperatures ranging from −2 C to +29 C were tested inDioscorea nipponica, D. tokoro, D. japonica, D. tenuipes, D. septemloba andD. quinqueloba which orginate in the temperate zone; they are distributed from northern cold areas to southern warm areas approximately
in this order in Japan. After water imbibition of these seeds, chilling induced full germination, and high temperatures over
23 C induced a secondary dormancy, but sensitivities to the chilling and to the high temperatures differed with species. Cold-climate
species germinated rapidly at higher temperatures after a short-term chilling or even without chilling, whereas warm-climate
species required chilling of a rather long period for germination; thus, among 6 species tested, favourable temperatures for
germination and climatic temperatures of distribution area were conversely correlated.
Seeds ofD. tokoro andD. japonica collected from several populations grown in different climates were also tested for germination at 11 to 29 C; seeds from
warm climates germinated rather slowly compared to seeds from cold climates.
These inte- and intra-specific adaptation manners in the temperature members of the genusDioscorea are entirely different from those of many other plant genera reported by some workers. 相似文献
96.
Abscisic acid (ABA) in extracts of somatic embryos and seeds of Gloryvine (Vitis vinifera L.xV. rupestris Scheele) was measured by gas chromatography-mass spectrometry-selected ion monitoring using deuterated ABA, (±)-[C-3Me-2H3]ABA, ([2H3]ABA) as internal standard. The ABA content increased rapidly during embryogeny (0.035 ng/embryo at the globular stage to 0.22 ng/embryo at the mature stage). The level of ABA in the tissues of somatic embryos, expressed in ng/mg dry weight, decreased from the globular stage (0.76 ng/mg) to the mature stage (0.25 ng/mg). Chilling (4° C) induced normal germination of seeds and mature somatic embryos and precocious germination of globular, heart-shaped and torpedoshaped somatic embryos. In all cases chilling led to a marked reduction in endogenous ABA. Exogenous (±)-ABA inhibited the germination of chilled somatic embryos.Abbreviations ABA
abscisic acid
- [2H3]ABA
(±)-[C-3Me-2H3]-abscisic acid
- BHT
2,6-di-t-butyl-4-methylphenol
- GC-MS
gas chromatography-mass spectrometry
- Me-ABA and Me-[2H3]ABA
methyl esters of ABA and [2H3]ABA, respectively
- SIM
selected ion monitoring 相似文献
97.
Geert Jan de Klerk 《Planta》1981,153(6):524-529
Isolated embryos are more suitable for in vivo study of protein synthesis than non-isolated embryos because, after isolation, the uptake of labeled amino acids is about 1000 times higher. However, isolation also stimulates protein synthesis: Up to 4 h after isolation, the capacity to incorporate labeled amino acids increased 7 times. Therefore, data on incorporation obtained with isolated embryos cannot be extended to non-isolated embryos. The increase of protein synthesis was not due to synthesis of specific proteins, but was a general increase. Furthermore, ripening, dormant, and afterripened embryos showed the same degree of increase. Isolation therefore stimulates protein synthesis nonspecifically. When embryos were kept under anaerobic conditions after isolation, protein synthesis did not increase. Therefore, higher oxygen consumption after removal of the seedcoat is probably the cause of the higher incorporation capacity. Furthermore, the activation of protein synthesis lagged several hours behind the increase of oxygen consumption.Abbreviations A
afterripened
- D
dormant
- pre-rRNA
precursor of ribosomal RNA 相似文献
98.
Effects of batatasins I, III and V, phenolic growth inhibitors occuring in dormant bulbils of Dioscorea batatas Decne., on photosynthetic reactions of chloroplasts from spinach (Spinacia oleracea L.) and on respiration of mitochondria from potatoes (Solanum tuberosum L.) were investigated. In chloroplasts, the batatasins effectively inhibited CO2-dependent oxygen evolution and electron flow from water to acceptors such as dichlorophenolindophenol, ferricyanide and methylviologen. Photosystem-I dependent electron transport from ascorbate to oxygen was stimulated. The proton conductivity of thylakoid membranes was increased and phosphorylation was uncoupled from electron transport. Inhibition of electron transport with water as electron donor appeared to precede uncoupling. In mitochondrial, batatasin I did not much inhibit succinate-dependent O2 uptake in the absence of ADP, but caused strong inhibition in the presence of ADP. Batatasins III and V inhibited oxygen uptake irrespective of the presence or absence of ADP. Inhibition of chloroplast and mitochondrial reactions by batatasins was shown to be reversible.Abbrevations B-I
batatasin I, 6-hydroxy-2,4,7-trimethoxyphenanthrene
- B-III
batatasin III, 3,3-dihydroxy-5-methoxybibenzyl
- B-V
batatasin V, 2-hydroxy-3,4,5-trimethoxybibenzyl
- Chl
chlorophyll
- MV
methylviologen
- DCPIP
2,6-dichlorophenol-indophenol
- DCMU
3-(3,4-dichlorophenyl)-1,1-dimethylurea
- PVP
polyvinylpyrrolidone 相似文献
99.
Overcoming dormancy in seeds with ethanol and other anesthetics 总被引:4,自引:0,他引:4
Dormancy in fall panicum (Panicum dichotomiflorum Michx.) caryopses (seeds) is overcome by imbibition at 35° C in ethanol solutions. Whereas germination in the absence of ethanol depends on active phytochrome, the seeds may germinate in darkness after treatment with 0.2 to 0.5 M ethanol. Ethanol overcomes dormancy also in seeds of several other weedy grass species. Ethyl ether, chloroform, methanol, and acetone act similarly to ethanol. We suggest that this action depends on modifyng the properties of a membrane(s) in a manner related to the actions of other anesthetics. 相似文献
100.
Fluence response curves for red light-induced germination of thermodormant (TD) seeds of Lactuca sativa L. show two regions that differ in their light sensitivity. In the region of high sensitivity, the germination responses differ between seed batches and can be altered by dark storage or far red irradiation. Induction of germination in far red dormant (FRD) seeds requires far higher fluences. Action spectra for induction to 60% germination were determined for these various response types. Spectra for the regions of low sensitivity response are similar for TD and FRD seeds. In comparison, the action spectrum for the highly sensitive response in TD seeds is significantly shifted to longer wavelengths. Analogous differences exist in the action spectra for far red reversal of the red induced germination responses. Germination induction in the low sensitivity region shows repeated red-far red reversibility. Far red reversal of red induction in the high sensitivity region does not saturate even at the highest far red fluences available and requires increased red fluences for subsequent reinduction. A model quantitatively accounting for these observations is presented. It is pointed out that action spectra of processes involving photoreversible pigments with partly overlapping absorption spectra in general are not identical with the absorption spectra of the partners. They should depend upon the degree of phototransformation required to elicit a given physiological response. In the case of induction of lettuce seed germination the observed action spectra can be interpreted as reflecting different requirements for P
fr of the various response types. Our results do not necessitate the assumption of spectroscopically different forms of phytochrome in these seeds.Abbreviations TD
thermodormant
- FRD
far red dormant
-
P
phytochrome
-
P
r
red absorbing form of P
-
P
fr
far red absorbing form of P 相似文献