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211.
Callus formation from protoplasts of Artemisia sphaerocephala Krasch and some factors influencing protoplast division 总被引:2,自引:0,他引:2
Round wormwood (Artemisia sphaerocephala Krasch) seeds were germinated on Murashige & Skoog (1962) medium without plant growth regulators. The hypocotyls of seedlings were sliced and cultured on M1 medium with 2,4-dichlorophenoxyacetic acid (9.05 M) to induce callus. The induced calluses were subcultured on the same medium. Ten day old calluses were used to isolate protoplasts in an enzyme solution with 0.65 M mannitol. Protoplast yield strongly depended upon the state of callus cultures. Certain amount of hemicellulase could improve protoplast isolation. Purified protoplasts were cultured in modified Kao & Michayluk (1975) medium with 0.60 M mannitol as osmoticum, suggesting that protoplasts of A. sphaerocephala need a high initial osmolarity. Protoplasts generally divided evenly and the percentage of first division could reach 10%. Kinetin exhibited a positive effect on initial cell division. Furthermore, we studied the effect of protoplast density and vitamin C on sustained growth of protoplasts. After forty days, 1 mm calluses in diameter formed.Abbreviations CH
casein hydrolysate
- 2,4-D
2,4-dichlorophenoxyacetic acid
- KM8P
Kao & Michayluk (1975) protoplast medium
- MS
Murashige & Skoog (1962) medium
- MES-2
(N-morpholino)ethanesulfonic acid 相似文献
212.
A. Borrell R. T. Besford T. Altabella C. Masgrau A. F. Tiburcio 《Physiologia plantarum》1996,98(1):105-110
Biosynthesis of polyamines in plants is controlled primarily by the enzymes ornithine decarboxylase (EC 4.1.1.17) and arginine decarboxylase (ADC: EC 4.1.1.19), which are responsible for the production of putrescine, and S -adenosyl-L-methionine (SAM) decarboxylase (EC 4.1.1.50) that is necessary for the formation of spermidine and spermine (Spm). Little is known about the metabolic or molecular mechanisms regulating the synthesis of these enzymes. We have studied the regulation of ADC synthesis by Spm in osmotically-stressed oat ( Avena sativa L. ev. Victory) leaves, using a polyclonal antibody to oat ADC and a cDNA clone encoding oat ADC. Treatment with Spm in combination with osmotic stress resulted in increased steady-state levels of ADC mRNA, yet the levels of ADC activity decreased. This absence of correlation is explained by the fact that Spm inhibits processing of the ADC proenzyme, which results in increased levels of this inactive ADC form and a consequent decrease in the ADC-processed form. Spermine treatment leads to delayed loss of chlorophyll in dark-incubated and osmotically-treated oat leaves. Thus, post-translational regulation of ADC synthesis by Spm may be important in explaining its anti-senescence properties. 相似文献
213.
Alterations in cell membrane structure and expression of a membrane-associated protein after adaptation to osmotic stress 总被引:3,自引:0,他引:3
214.
Regional lipid peroxidation and protein oxidation in rat brain after hyperbaric oxygen exposure 总被引:8,自引:0,他引:8
Reactive oxygen species may participate in development of neurological toxicity resulting from hyperbaric oxygen exposure. To explore the possibility that increased reactive O2 metabolite generation may result in oxidative modification of lipids and proteins, rats were exposed to five atmospheres (gauge pressure) of O2 until development of an electroencephalographic seizure. Lipid peroxidation (as thiobarbituric acid-reactive substances) and protein oxidation (as 2,4-dinitrophenyl-hydrazones) were measured in five brain regions. Oxidized and reduced glutathione were also determined because of their role in regulating lipid peroxidation. Lipid peroxidation was confined to the frontal cortex and hippocampus, while protein oxidation (in both cytoplasmic and membranous fractions) and increased oxidized glutathione was evident throughout the brain. These results support a role for formation of reactive O2 metabolites from hyperbaric O2 exposure and suggest that protein oxidation, especially in soluble proteins, may be one of the most sensitive measures. 相似文献
215.
216.
Concanamycin 4-B, a macrolide antibiotic with an 18-membered lactone ring, is known as a specific inhibitor of the vacuolar type of H+-ATPase, as is bafilomycin A1. The drug was tested for its effect on regulation of the vacuolar pH (pHv) of internodal cells of a fresh water characean alga, Chara corallina, under normal conditions and under salt stress. The pHv was measured either on isolated vacuolar sap with a conventional pH electrode or directly by inserting a pH-sensitive glass microelectrode into the vacuole. Proton-pumping into tonoplast vesicles was almost completely inhibited by concanamycin 4-B at 1 nM. Concanamycin 4-B at 1 μM significantly increased pHv while bafilomycin A1 was ineffective when applied at 1 μM. Concanamycin 4-B did not affect pHv when applied at 0.1 μM and increasing the concentration to 10 μM did not amplify the degree of alkalization. Concanamycin 4-B also inhibited pHv regulation under NaCl stress. When Chara cells were treated with 100 mM NaCl, pHv promptly increased and then recovered to the original level. The reacidification was completely inhibited by concanamycin 4-B (1 μM), suggesting that the reacidification was achieved by the H+-ATPase of the tonoplast. 相似文献
217.
Ariela Baruch Moshe Shani David R. Hurwitz Itamar Barash 《Genesis (New York, N.Y. : 2000)》1995,16(3):241-252
218.
利用人粒细胞集落刺激因子(hG-CSF)cDNA3′端非翻译区(3′-UTR)中存在的DraⅠ酶切位点,通过部分酶切与完全酶切,删除3′-UTR不同长度,构建了四种hG-CSFcDNA瞬时重组表达质粒。转染COS-7细胞后,生物活性测定结果提示,hG-CSFcDNA3′-UTR对其表达起负调控作用,其关键性序列位于紧接终止密码子TGA下游的65bp范围内,3′-UTR对hG-CSFcDNA表达的影响与转录水平的差别有一定关系。 相似文献
219.
DNaseⅠ超敏感位点的研究能够发现潜在的调控基因转录活化的位点,比较正常人外周血有核细胞,淋巴瘤细胞株P3HR1和人鼻咽癌低分化磷癌细胞株HOnE1和HNE2中Ha-ras-1瘤基因的DNaseⅠ超敏感位点发现,只有HONE1和HNE2细胞基因组中存在一个DNaseⅠ超敏感位点,位于第一个外显子上游0.37kb处,上述结果提示正常白细胞和P3HR1细胞中Ha-ras-1基因处于失活状态,而在鼻咽癌细胞基因组中则处于活化状态,它的活化可能与0.37kb处的DNA序列有密切的关系。 相似文献
220.
We investigated the relationships between social dominance,competition for food, and strategies of body mass and fat regulationin the European starling (Sturnus vulgaris). In birds housedin groups of three, subdominant birds stored more fat than dominants.A removal experiment established a causal link between socialdominance and fat reserves; in groups that had the dominantindividual removed, the remaining birds reduced body mass andfat, relative to control groups that had the subordinate removed.In a second experiment, we investigated the influences of degreeof competition for food and dominance on body mass and fat reserves.Birds under high competition increased fat reserves and tendedto have higher body mass than birds under low competition. Theincrease in fat reserves was higher in the subdominants thanin the dominants. These results are consistent with hypothesesconcerning dominance-dependent access to food; subdominant birds,or birds under increased competition, may store more fat asan insurance against periods when food cannot be obtained. However,relations between dominance, body mass, and fat reserves mayalso arise through other proximate factors relating to dominance-dependentcosts and benefits of fat storage, such as predation risk andenergetic expenditure. 相似文献