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Drought signal transduction in plants 总被引:5,自引:0,他引:5
Anders B. Jensen Peter K. Busk Mercé Figueras M. Mar Albà Giovanna Peracchia Ramon Messeguer Adela Goday Montserrat Pagès 《Plant Growth Regulation》1996,20(2):105-110
Water deficit is one of the most common environmental limitations of crop productivity by affecting growth through alterations in metabolism and gene expression. The mechanisms involved in drought perception and signal transduction pathways are poorly understood. The participation of the plant hormone abscisic acid (ABA) has been well established. ABA levels increase when there are changes in the environment that result in cellular dehydration. Different approaches have been taken to understanding the molecular responses to desiccation and how ABA regulates gene expression. Recent efforts have identified particular topics of importance in the dissection of the signal transduction pathway which are summarized as follows: physiological approaches: identification of signalling molecules. Genetic approaches: the use of mutants, and Molecular approaches: promoter analysis. 相似文献
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M-Enterococcus medium, used for the detection and enumeration of fecal streptococci from different types of water, demonstrated a very low specificity. We propose the transfer of membrane filters to bile-esculin medium as a confirmation technique. It has proved to be more reliable, faster to perform, and more effective than the random selection of colonies, which is recommended for confirmation in Standard Methods for the Examination of Water and Wastewater (A.E. Greenberg, L.S. Clesceri, and A.D. Eaton, ed., 1992). 相似文献
4.
Miquel Marc David S. Brown Teresa Capell Xavier Figueras Antonio F. Tiburcio 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1995,666(2)
A rapid high-performance liquid chromatographic method for the separation of polyamines as their dansyl derivative has been developed. The chromatographic system used consisted of a reversed-phase column and a mobile phase of acetonitrile and water. The separation of 1,3-diaminopropane, putrescine, cadaverine, spermidine and spermine takes only 9 min. This method provides a good resolution between 1,3-diaminopropane and putrescine. It has been applied to quantify polyamines from seeds of wheat, petals of Phalaenopsis hybrids and various rat tissues. 相似文献
5.
Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews
(genus Sorex) for the region between the tRNA(Pro) and the conserved
sequence block-F revealed variable numbers of 79-bp tandem repeats. These
repeats were found in all 19 individuals sequenced, representing three
subspecies and one closely related species of the masked shrew group (Sorex
cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an
outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an
adjacent 76-bp imperfect copy of the tandem repeats. One individual was
heteroplasmic for length variants consisting of five and seven copies of
the 79-bp tandem repeat. The sequence of the repeats is conducive to the
formation of secondary structure. A termination-associated sequence is
present in each of the repeats and in a unique sequence region 5' to the
tandem array as well. Mean genetic distance between the masked shrew taxa
and the pygmy shrew was calculated separately for the unique sequence
region, one of the tandem repeats, the imperfect repeat, and these three
regions combined. The unique sequence region evolved more rapidly than the
tandem repeats or the imperfect repeat. The small genetic distance between
pairs of tandem repeats within an individual is consistent with a model of
concerted evolution. Repeats are apparently duplicated and lost at a high
rate, which tends to homogenize the tandem array. The rate of D- loop
sequence divergence between the masked and pygmy shrews is estimated to be
15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid
sequence evolution in shrews may be due either to their high metabolic rate
and short generation time or to the presence of variable numbers of tandem
repeats.
相似文献
6.
Recent advances in the understanding of polyamine functions during plant development 总被引:15,自引:0,他引:15
Suggested roles for polyamine function, and the evidence for these functions, is reviewed. These include membrane stabilization, free radical scavenging, effects on DNA, RNA and protein synthesis, effects on the activities of RNase, protease and other enzymes, the interaction with ethylene biosynthesis, and effects on second messengers. It is concluded that in addition to interacting with plant hormones, polyamines are able to modulate plant development through a fundamental mechanism(s) common to all living organisms.Abbreviations ACC
1-aminocyclopropane-1-carboxylic acid
- ADC
arginine decarboxylase
- Chl
chlorophyll
- DAP
diaminopropane
- DFMA
DL--difluoromethylarginine
- DFMO
DL--difluoromethylornithine
- PAs
polyamines
- Put
putrescine
- SAM
S-adenosylmethionine
- Spd
spermidine
- Spm
spermine 相似文献
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大鼠胼胝体内神经肽Y免疫反应阳性纤维的发育 总被引:1,自引:0,他引:1
本实验用免疫组织化学ABC法研究了大鼠胼胝体内神经肽Y免疫反应阳性(NPY-IR)纤维的生后发育。结果发现,许多NPY-IR纤维在大鼠出生时便存在于胼胝体内。NPY-IR胼胝体纤维的密度在生后1周内继续逐渐增高,在第2周内达到最高峰。之后,NPY-IR胼胝体纤维的密度逐渐下降,至第3周末时接近成年时的水平,即仅有少量NPY-IR纤维存在于胼胝体内。这些结果提示在大鼠早期生后发育过程中许多NPY-IR胼胝体纤维是暂时性的,其作用可能与大脑皮质的机能发育有关。 相似文献
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