苹果幼苗侧根形成与内源多胺关系的通径分析(英文)

本文采用偏回归和通径分析研究苹果幼苗侧根形成与内源多胺含量之间的关系。多胺对苹果幼苗侧根形成有重要的调节作用,内源多胺的水平高低与侧根数量之间有显著的线性相关。腐胺、亚精胺和精胺对侧根形成的影响不同,它们对侧根数量的直接通径系数分别是0.0756,0.1558和0.8023。因而表明精胺在增加侧根数量中的作用最大,而亚精胺和腐胺几乎没有直接的作用。不过,亚精胶和腐胺通过影响精胺水平,对侧根形成有很大的间接作用。     

黄瓜花性别分化与内源多胺的关系

研究了黄瓜雌、雄花几个主要发育时期和性别逆转过程中内源多胺的变化。结果表明 ,雄花在不同发育时期 ,内源腐胺含量均高于雌花 ,腐胺含量的显著升高伴随着花粉粒的形成 ,高腐胺含量是雄花发育的特征。雌花在大孢子母细胞时期以后直到雌花发育成熟 ,其内源尸胺含量均高于雄花 ,高尸胺含量可能有利于雌花的发育。高水平的内源多胺、精胺和亚精胺可能有利于雌花大孢子母细胞的形成。亚精胺和腐胺含量随着大小孢子四分体形成和大孢子核的连续分裂而分别表现下降和上升。雌性系黄瓜经硝酸银诱导雄花处理后 ,茎尖内源亚精胺含量下降 ,腐胺含量上升 ,从而诱导雄花形成 ;雄性系黄瓜经乙烯利诱导雌花处理后 ,茎尖内源亚精胺含量上升 ,腐胺含量下降 ,从而诱导雌花形成     

NaCl胁迫下外源亚精胺和二环己基胺对滨藜内源多胺含量和抗盐性的影响

受高浓度NaCl胁迫的滨藜叶中内源腐胺（Put)、叶绿素、丙二醛（ＭＤＡ）的含量,腐胺／多胺（Put/PA)值以及相对电导率明显增加,内源亚精胺（Spd)、精胺（Spm）、蛋白质的含量和含水量显著下降。,外施亚精胺可以逆转NaCl的胁迫效应,外施二环己基胺（ＤＣＨＡ）的作用与外施亚精胺的相反。     

水稻细胞质雄性不育系幼穗发育过程中多胺与乙烯的关系初探(英文 )

利用ＨＰＬＣ和ＧＣ分别测定了水稻细胞质雄性不育系及其保持系幼穗多胺（ 腐胺,亚精胺和精胺） 含量和乙烯释放速率,并研究了外施多胺合成抑制剂ＭＧＢＧ 和乙烯前体ＡＣＣ生成抑制剂ＡＶＧ 对两系幼穗多胺含量和乙烯释放速率以及花粉育性的影响。结果表明, 不育系幼穗乙烯释放速率显著高于其保持系幼穗, 外施ＡＶＧ 引起两系幼穗乙烯释放速率下降,并使不育系花粉育性得以部分恢复; 不育系幼穗多胺含量显著低于保持系幼穗, 外施ＭＧＢＧ 使两系幼穗Ｓｐｄ 和Ｓｐｍ 含量下降, 并使保持系花粉育性降低。外施ＡＶＧ 抑制乙烯释放,促进多胺合成;而外施ＭＧＢＧ 抑制Ｓｐｄ和Ｓｐｍ 合成, 却促进乙烯的释放; 而且,乙烯释放速率与多胺（精胺和亚精胺） 含量呈显著负相关。提示在水稻ＣＭＳ 系及其保持系幼穗发育过程中乙烯与多胺（ 精胺和亚精胺） 的生物合成竞争ＳＡＭ。     

采后香蕉果实中多胺含量的变化

以巴西香蕉为试材,研究了果实中主要多胺类型,以及随贮期延长,果皮和果肉中精胺,亚精胺和腐胺3种多胺的变化情况。研究结果表明,在巴西香蕉果实中含有精胺,亚精胺和腐胺3种类型。随着贮期延长,精胺,亚精胺含量有所下降或基本保持不变,而腐胺则有所增加,这种变化在果皮,果肉中基本相同。     

多胺及其合成抑制剂MGBC对稀脉萍成花反应的影响

腐胺、亚精胺和精胺对稀脉萍的成花均有一定的抑制作用,这种作用随多肢的浓度增加而增强。多胺合成抑制剂MGBG强烈抑制稀脉萍群体的增殖速率,并使稀脉萍群体在非诱导光周期下开花。这种由MGBG引起的增殖速率的降低及成花诱导作用均可被多胺逆转。稀脉萍成花诱导过程中,内源腐胺含量显著升高,亚精胺则下降。     

多胺对神经退行性疾病的改善作用

多胺(polyamines)普遍存在于各种生物体中,参与多种生物学功能,包括细胞生长和增殖、蛋白质和核酸的合成、免疫细胞的分化、炎症反应的调节以及肠道功能的维持等。多胺主要包括腐胺(putrescine)、亚精胺(spermidine)、精胺(spermine)以及胍丁胺(agmatine)。随着衰老进程的发展,细胞内的多胺水平会逐渐随之降低。在衰老相关的神经退行性疾病的发生和发展过程中,多胺具有积极的作用。因此,本文就多胺对神经退行性疾病的改善作用作一综述,期望可以对未来神经退行性疾病的治疗和缓解提供参考。     

多胺对渗透胁迫下甘蔗愈伤组织诱导和分化的作用

0．4mmol／L的多胺（精胺、亚精胺和腐胺）处理渗透胁迫下的甘蔗心叶或愈伤组织后,愈伤组织的诱导和绿苗的分化受到促进,苗重增加;SOD和过氧化氢酶活性增强,谷胱苷肽含量增多,MDA含量下降。精胺、亚精胺的效果优于腐胺。     

外源钙和亚精胺对NaCl胁迫条件下玉米幼苗体内离子平衡和多胺 …

研究了钙离子和亚精胺对盐胁迫条件下玉米幼苗生长状况、电解质渗漏、离子含量和多胺水平的影响。结果表明：盐胁迫下,钠离子和腐胺含量升高,质膜受到严重伤害,而钾离子、钙离子、亚精胺以及精胺水平降低。外加氯化钙和亚精胺不但能逆转氯化钠带来的离子平衡失调１多胺代谢紊乱,而且还能减轻氯化钠导致的生长抑制和质膜伤害,在盐胁迫条件下,二环己基胺引起多胺含量严重下降的情况在一定程度上能被外加氯化钙处理所缓解。这些结     

月季切花衰老过程中多胺与乙烯的关系

月季切花瓶插过程中,内源腐胺在前2天略有增加,内源亚精胺、精胺、多胺总量则呈下降趋势,乙烯释放速率在第3天达到最高峰;多胺抑制剂甲基乙醛-双咪腙处理抑制了亚精胺、精胺的合成,增加了乙烯的释放速率;乙烯抑制剂氨氧乙酸处理推迟腐胺高峰的到来,降低了乙烯的释放速率,而且在瓶插期的前2天内源亚精胺、精胺含量较高。结果表明,具乙烯跃变型特征的月季切花衰老过程中,多胺与乙烯在其生物合成过程中相互竞争S-腺苷甲硫氨酸作为其合成的前体。     

Metabolism of l[U-14C]-arginine and l[U-14C]-ornithine in maturing and vernalised embryos and megagametophytes of Picea abies

The metabolism of the polyamine precursors arginine and ornithine was studied in maturing and vernalised seeds of Picea abies (L.) Karst. (Norway spruce) in feeding experiments. Incorporation of radioactivity from these 14 C-labelled amino acids into liberated CO₂, amino acids, polyamines, proteins and cell wall fractions, as well as polyamine levels were determined in embryos and megagametophytes. Ornithine and especially arginine decarboxylation was more active in the embryo than in the megagametophytic cells, and vernalisation increased arginine metabolism more than it increased ornithine metabolism. Both precursors were metabolised to each other, to other amino acids, and to polyamines. The only polyamine in which radioactivity incorporated was free putrescine, showing either a slow synthesis or a high degradation rate of spermidine and spermine in maturing spruce seeds. The putrescine level was approximately 10 times higher in the embryo than in the megagametophytic tissues, whereas spermidine and spermine levels were almost the same in both tissues. The label from arginine and ornithine was also incorporated into proteins as amino acids and post-translationally as polyamines. Higher radioactivity was seen in the small ≤14-kDa polypeptides. Protein hydrolysates of the embryo and the megagametophytic tissues contained spermidine and spermine and their degradation product 1,3-diaminopropane (DAP), suggesting that polyamines may play a role in the accumulation of seed storage protein and in the maturation of spruce seeds.     

Polyamines and their biosynthetic enzymes during somatic embryo development in red spruce (<Emphasis Type="Italic">Picea rubens</Emphasis> Sarg.)

Summary The major objective of this study was to determine if the observed changes in polyamines and their biosynthetic enzymes during somatic embryo development were specifically related to either the stage of the embryo development or to the duration of time spent on the maturation medium. Somatic embryos of red spruce (Picea rubens) at different developmental stages, grown in the embryo development and maturation media for various lengths of time, were separated from the associated subtending tissue (embryogenic and the suspensor cell masses) and analyzed for their polyamine content as well as for polyamine biosynthetic enzyme activities. Polyamine content was also analyzed in embryos representing different stages of developmentthat were collected from the sam culture plate at the same time and the subtending tissue surrouding them. Putrescine was the predominant polyamine in the pro-embryogenic tissue, while spermidine was predominant during embryo development. Significant changes in spermidine/putrescine and spermine/putrescine ratios were observed at all stages of embryo development as compared to the pro-embryogenic cell mass. Changes in the ratios of various polyamines were clearly correlated with the developmental stage of the embryo rather than the period of growth in the maturation medium. Whereas the activities of both ornithine decarboxylase and arginine decarboxylase increased by week 3 or 4 and stayed high during the subsequent 6 wk of growth, the activity of S-adenosylmethionine decarboxylase steadily declined during embryo development.     

Changes in Polyamine Contents Development of the Frog, Microhyla ornata

Putrescine, spermidine and spermine levels were measured during development, metamorphosis and adult life of the frog, Microhyla ornata . Development of Microhyla was accompanied by high fluctuating levels of putrescine and spermidine with low and steady levels of spermine. Putrescine was the major polyamine during development from egg to mature tadpole. During metamorphosis both putrescine and spermidine decreased significantly; but the decrease in putrescine content was more rapid than that of spermidine. Thus, in the freshly metamorphosed frog, the concentration of spermidine exceeded that of putrescine. In most of the adult tissues also spermidine concentration was higher than putrescine and spermine. While the free form of putrescine and spermidine increased during early development of the fertilized egg to tadpole, the levels of protein conjugated polyamines decreased. In the free form, putrescine was the major polyamine while in the protein conjugated form spermidine concentration was higher than putrescine and spermine. Thus polyamine pattern is different in early development, during metamorphosis and in differentiated adult tissues of this frog. ∞-Difluoromethylornithine treatment at early blastula stage did not interfere with the normal development of Microhyla embryos.     

伏令夏橙愈伤组织体细胞胚发生中多胺水平的变化

以继代培养8年的伏令夏橙愈伤组织为材料,研究了不同类型愈伤组织体细胞胚发生能力的差异和多胺水平的变化及两者之间的关系.结果表明,胚性愈伤组织的多胺含量高于非胚性愈伤组织,体细胞胚发生能力与多胺水平呈正相关.体细胞胚发生早期Put含量的增加有利于体细胞胚发生.球形胚大量形成时,Spd达到最高值;球形胚发育后期并有少量心形胚形成时Spm达到峰值.随着倍性的增加,伏令夏橙体细胞胚发生能力降低.精氨酸脱羧酶的活性变化与Put水平呈正相关,表明它是调节伏令夏橙体细胞胚发生中多胺水平的重要因子.     

Polyamine oxidase activity and polyamine content in maize during seed germination

Polyamine oxidase (PAO, EC 1.5.3.3) activity and polyamine content in the cell wall and soluble fractions obtained from embryos, endosperms and shoots and roots of etiolated or green seedlings of maize ( Zea mays L. cv. WF9) during the first 7 days of germination were investigated. Polyamine content was also determined in the trichloroacetic acid-soluble (free polyamines) and trichloroacetic acid insoluble (bound polyamines) fraction obtained from the same tissues. PAO activity, determined by the radiometric method based on the recovery of the labelled reaction product 1-pyrroline, was mostly localized in the cell wall fraction. The activity was very low in embryos and endosperms and present in traces in roots. In etiolated shoots PAO activity increased sharply, while in green shoots it was low and increased slowly. No polyamines were found in the cell wall fraction and only putrescine was detected in the soluble fraction, with the exception of the embryo, where spermidine and spermine were also present. In the TCA-soluble fraction of embryos, putrescine increased during imbibition, while spermidine and spermine decreased; in the endosperm no relevant changes in polyamines occurred. In the same fraction of green and etiolated seedlings, putrescine increased, giving a peak at days 3–5, while spermidine decreased to very low levels. The amount of bound polyamines was 1–4% of the free ones. The pattern of PAO activity seems to be unrelated to endogenous free polyamine content, which is the same in shoots and roots of etiolated and green seedlings. Enzyme activity, very low in ungerminated seeds, increased continuously during the progression of germination, especially in etiolated shoots, indicating a possible involvement in cell wall formation.     

Polyamines as modulators of salt tolerance in rice cultivars

The effect of NaCl on the endogenous levels of diamine, putrescine and polyamines, spermidine and spermine, was studied in the shoot system of salt-tolerant and salt-sensitive lines of rice (Oryza sativa L.) cultivars during three growth stages. Salt stress increased the levels of diamine and polyamine in varying degrees among nine rice cultivars investigated. Salt tolerant AU1, Co43, and CSC1 were effective in maintaining high concentrations of spermidine and spermine, while the content of putrescine was not significantly altered in all the growth stages when plants were exposed to salinity. The salt sensitivity in rice was associated with excessive accumulation of putrescine and with low levels of spermidine and spermine in the shoot system of salt-sensitive cultivars Co36, CSC2, GR3, IR20, TKM4, and TKM9 under saline condition. One of the possible mechanisms of saline resistance was observed to be due to the highly increased polyamines against the low increase in diamines. Alternatively, the salt sensitivity could be due to high increase of diamines and an incapacity to maintain high levels of polyamines.     

Floral morphogenesis in Rudbeckia hirta in relation to polyamine concentration

Changes in polyamine concentration in the long day (LD) plant Rudbeckia hirta were examined over the course of floral initiation and development. Plants of R. hirta were grown to maturity under 9h, non-floral-inductive photoperiods. At maturity, half the plants were placed in ambient day length plus a 4- h night interruption. Plants were sampled at 0, 4, 8, 12 or 16 days for polyamine content and floral initiation. Polyamines were extracted from fully expanded leaves and the meristems were examined histologically. In another experiment, polyamines were extracted from the meristems under paired LD and short day (SD) conditions every 2 days from 0 to 22 days. A rise in free polyamines was linked to important cytological events during floral initiation. Free putrescine and spermidine levels increased after 4 LD and continued until 14 to 16 LD when the levels in the meristem began to decline. Events of floral initiation began between 4 and 8 LD with cell proliferation and the start of stem elongation. Initiation was irreversible after 14 to 16 LD, the period when putrescine and spermidine began to decline. After 4 LD, the polyamine level was consistently higher in the photoinduced plants. Our results from this study, using direct histological comparisons of meristematic development and polyamine concentration, clearly demonstrate a correlation of polyamines and flowering.     

Polyamine changes during the development of zygotic embryos in Prunus avium

A study of the polyamine profile was carried out during zygotic embryo development in Prunus avium. Zygotic embryos were collected from 2 donor trees and sorted into 3 size classes: C1 [2.5 to 3.5 mm]; C2 [3.6 to 4.5 mm] and C3 [5.5 to 7 mm]. Evolution of the various polyamines was similar for the two donor trees. Changes in the relative amount of the various free polyamines were observed during zygotic embryo development. Agmatine and spermine levels increased from C1 to C3. Spermidine, the predominant polyamine, showed a two-fold decrease in C3 compared with C1 and C2; the evolution of putrescine was opposed, showing an increase in the last developmental stage. The putrescine/spermidine ratio could be a marker for these 3 developmental stages with a higher ratio in C3 compared with C1 and C2. Polyamine changes in cotyledons from class C1 were investigated during in vitro culture. A 10-day induction on a medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin caused a strong decline in free spermidine levels and a dramatic increase in free putrescine. The formation of conjugated putrescine occurred simultaneously, and twenty days after removal of growth regulators, the various polyamine contents were still at the same level.Abbreviations Agm agmatine - Dap diaminopropane - 2,4-D 2,4-dichlorophenoxyacetic acid - Put putrescine - Spd spermidine - Spm spermine     

Cellular content and biosynthesis of polyamines during rooster spermatogenesis.

The natural polyamines spermine and spermidine, and the diamine putrescine, were extracted from rooster testis cells separated by sedimentation at unit gravity, and from vas-deferens spermatozoa. The ratios spermine/DNA and spermidine/DNA were kept relatively constant throughout spermatogenesis, whereas the ratio putrescine/DNA rose in elongated spermatids. The cellular content of spermine, spermidine and putrescine decreased markedly in mature spermatozoa. Two rate-limiting enzymes in the biosynthetic pathway of polyamines, ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase, showed their highest activities at the end of spermiogenesis and were not detectable in vas-deferens spermatozoa. A marked reduction in cell volume during spermiogenesis without a parallel decrease in the cellular content of polyamines suggests the possibility that the marked changes in chromatin composition and structure occurring in rooster late spermatids could take place in an ambience of high polyamine concentration.     

Polyamine biosynthesis in the developing rabbit palate

Levels of putrescine, spermidine, and spermine and their biosynthetic enzymes, ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) were measured in the developing rabbit palate between day 14 and day 18 of gestation. DNA, RNA, and protein synthesis were also measured during this time period to determine if a correlation exists between polyamine biogenesis and macromolecular synthesis. ODC activity was found to be twice as high on day 14 as on the succeeding days of gestation, while SAMDC activity did not change significantly. Levels of putrescine and spermine were higher on day 14 by 22% and 30%, respectively, than levels on day 18. Spermidine concentration did not change. DNA synthesis remained relatively constant between days 14 and 18 of gestation, suggesting that there is no peak in cell proliferation during this period. RNA synthesis was elevated significantly on day 14 and protein synthesis was significantly higher on both days 14 and 16. This data indicates that there is no correlation between polyamine synthesis and cell proliferation during this period of palatal development, but polyamines could play a regulatory role in RNA and/or protein synthesis.