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1.
A quantitative analysis of JPH scalar couplings in nucleic acids is difficult due to small couplings to phosphorus, the extreme overlap of the sugar protons and the fast relaxation of the spins involved in the magnetization transfer. Here we present a new methodology that relies on heteronuclear Constant Time Correlation Spectroscopy (CT-COSY). The three vicinal 3JPH3, 3JPH5 and 3JPH5 scalar couplings can be obtained by monitoring the intensity decay of the Pi-H3i – 1 peak as a function of the constant time T in a 2D correlation map. The advantage of the new method resides in the possibility of measuring the two 3JPH5 and 3JPH5 scalar couplings even in the presence of overlapped H5/H5 resonances, since the quantitative information is extracted from the intensity decay of the P-H3 peak. Moreover, the relaxation of the H3 proton is considerably slower than that of the H5/H5 geminal protons and the commonly populated conformations of the phosphate backbone are associated with large 3JPH3 couplings and relatively small 3JPH5 / H5. These two facts lead to optimal signal-to-noise ratio for the P-H3 correlation compared to the P-H5/H5 correlation.The heteronuclear CT-COSY experiment is suitable for oligonucleotides in the 10–15 kDa molecular mass range and has been applied to the 30mer HIV-2 TAR RNA. The methodology presented here can be used to measure P-H dipolar couplings (DPH) as well. We will present qualitative results for the measurement of P-Hbase and P-H2 dipolar couplings in the HIV-2 TAR RNA and will discuss the reasons that so far precluded the quantification of the DPHs for the 30mer RNA. 相似文献
2.
Summary We have synthesized 2(3)-O-(glycyl)-adenosine-5-(O-methylphos-phate), an analogue of the 3-terminus of aminoacylated tRNA. A 0.4M solution of this compound maintained at pH 8.2, yields 5.5% of diglycine and 11.5% of diketopiperazine, in addition to the hydrolysis products glycine and adenosine-5-(O-methylphosphate). Under the same conditions, glycine ethyl ester reacts much more slowly, but ultimately gives similar yields of diglycine and diketopiperazine.The aminolysis of 2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate) by free glycine is relatively inefficient, but serine reacts 20 times more rapidly and yields up to 50% of N-glycylserine. The prebiotic significance of these reactions is discussed.Abbreviations MepA
adenosine-5-(O-methylphosphate)
- MepA-gly
2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate)
- MepA-bis-gly
2,3-O-(bis-glycyl)-adenosine-5-(O-methylphosphate)
- DKP
diketopiperazine
- gly Et
glycine ethyl ester
- gly-ser
N-glycylserine
- O-gly-ser
O-glycylserine
- O-(gly)-gly-ser
O-(glycyl)-glycylserine
- Boc-gly
N-tert-butyloxycarbonylglycine
- MepA-Boc-gly
2(3)-O-(Boc-glycyl)-adenosine-5-(O-methylphosphate)
- MepA-bis-Boc-gly
2,3-O-(bis-Boc-glycyl)-adenosine-5(O-methylphosphate)
- (gly)2
diglycine
- (gly)3
triglycine 相似文献
3.
Adventitious shoot regeneration was compared among leaf, stem and petal explants of carnation (Dianthus caryophyllus L.) cv. Scania on MS medium containing different concentrations of 6-benzyladenine (BA) and -naphthaleneacetic acid (NAA). High frequency regeneration was obtained only from petal explants on the media containing 5 to 10 M BA with or without 5 M NAA. Among the cytokinins tested, N-2-chloro-4-pyridyl-N-phenylurea and N-1,2,3-thiadiazol-5-yl-N-N-phenylurea were more effective than BA, kinetin, N6-2-isopentenyl adenine and zeatin on regeneration from petal explants. Although, high frequency shoot regeneration was obtained from all petal explants harvested from various developmental stages of buds, a significant decrease in regeneration capacity was observed in the explants obtained from fully-opened flowers. High frequency shoot regeneration was also obtained from the petal explants of cvs. Coral. Lena, Nora and White Sim, and an interspecific cultivar Eolo using the method developed in this study.Abbreviations NAA
-naphthaleneacetic acid
- BA
6-benzyladenine
- GA3
gibberellic acid
- 2iP
N6-2-isopentenyl adenine
- KT-30
N-2-chloro-4-pyridyl-N-phenylurea (also called 4PU)
- TDZ
N-1,2,3-thiadiazol-5-yl-N-phenylurea (also called thidiazuron) 相似文献
4.
Summary Organic pyrophosphates such as UppA and NAD are formed when a solution containing a nucleotide, a nucleoside 5-polyphosphate, Mg2+ and imidazole are allowed to dry out. We suggest that this synthesis may have occured concurrently with oligonucleotide formation.Abbreviations Im
Imidazole
- CDI
1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride
- EDTA
ethylenediaminetetraacetic acid
- A
adenosine
- U
uridine
- pnA
adenosine 5-poly-phosphate containing n phosphate residues
- pU
uridine 5-phosphate
- AppA
P1,P2-diadenosine 5-pyrophosphate
- UppA
P1-(uridine 5)-P2-(adenosine 5)-pyrophosphate
- ImpA
adenosine 5-phosphorimidazolide
- NMN
nicotinamide mononucleotide
- NAD
nicotinamide-adenine dinucleotide 相似文献
5.
As part of our investigation of the mode of action of plant hormones in barley (Hordeum vulgare L.) aleurone layers, we have studied the expression of five identified and three unidentified mRNA species in the presence of exogenous gibberellic acid (GA3) and abscisic acid. Three of the mRNAs are GA3-inducible, three are suppressed by GA3, and two are constitutive. The extent of the GA3 effect differs considerably for both inducible and suppressible mRNAs. For example, a ten-fold higher concentration of GA3 (10-8 M) is required for full induction of the high-pl group -amylase mRNA than is required for the low-pI -amylase mRNA (10-9 M). Temporal regulation of mRNA abundance also varies between the two -amylase isoenzyme groups. The three GA3-suppressible mRNA species studied, alcohol dehydrogenase (ADH1), a probable amylase and protease inhibitor, and an unidentified barley mRNA species also varied in response to GA3. The ADH1 mRNA decreased drastically within 8 h of GA3 treatment, whereas the other two began to decrease in abundance only after 12–16 h of GA3 treatment. Abscisic-acid treatment counteracted the GA3 effects for both the inducible and suppressible mRNA species. Comparison of -amylase-mRNA levels and -amylase-synthesis rates showed a strong correlation between the two parameters, the only exception being a lack of -amylase synthesis in the presence of -amylase mRNA at low GA3 concentrations. Therefore, the expression of -amylase seems to be regulated primarily by its mRNA levels.Abbreviations ABA
abscisic acid
- ADH1
alcohol dehydrogenase 1
- cDNA
copy DNA
- GA3
gibberellic acid
- PAPI
probable amylase/protease inhibitor 相似文献
6.
Summary The angular dependence of1JC,H in model compounds related to -linked oligosaccharides has been established by FPT INDO quantum chemical calculations. Values calculated for models of (1 1)-, (1 2)-, (1 3)- and (1 4)-linked disaccharides were compared, and the effect of the orientation of HO-2 elucidated. The angular dependence of1JC,H on the torsional angles H and H and the solvent dielectric constant (s) was characterized in the form:1JC,H = A cos2+B cos + C sin2 + D since + E + Fe. The1JC,H values, measured by DEPT methods for C-1-H-1 and C-X-H-X in cellobiose, cyclic trisaccharide and hexopyranoses were used to adjust the calculated angular dependences. Based on the occurrence of the conformers for agarobiose, neoagarobiose, mannobiose and methyl -xylobioside, the thermodynamically averaged <1JC,H > values were calculated. The results obtained (<1JC-1,H-1 > 162.4, <1JC-4, H-4 > 147.6 Hz for methyl -xylobioside; <1JC-1,H-1 > 162.4 and <1JC-4,H-4] > 147.6 Hz for mannobiose; <1JC-1,H-1 > 162.8 Hz for neo agarobiose and <1JC-1,H-1 > 163.2 Hz for agarobiose) agree well with the experimental values of 162.7, 147.5, 160.4, 147.2, 160.9 and 165.7 Hz, respectively. 相似文献
7.
2D NMR spectroscopy and J coupling constant analysis are applied to resolve the structure of two photoproducts of thymidylyl-(35)-thymidine. These products are cyclobutane type thymine dimers possessing the cis-syn (the predominant one) and trans-syn geometry. The cis-syn is formed in an ANTI-ANTI conformation about the N-glycosyl linkages and resembles the normal base-stacked configuration. The glycosidic conformation in solution of the 5 terminal fragment differs from the crystal in which the less common SYN conformation is observed. In this isomer only the sugar pucker of the 3 terminal fragment is changed substantially with respect to the dinucleotide. The trans-syn isomer is formed in a SYN-ANTI glycosidic conformation. In this isomer the sugar puckers of both deoxyribose rings are affected and a preference for a pure 2-endo conformation is observed.Abbreviations dTpdT
2-deoxythymidylyl-(35)-2-deoxythymidine
- dTp[]dT
cyclobutane type photodimers of dTpdT
- dTp- and dTp[]-
their 5' terminal fragments (fragment A)
- -pdT and-[]pdT
their 3 terminal fragments (fragment B)
- RP-HPLC
reversed-phase high-performance liquid chromatography
- COSY
two-dimensional correlated spectroscopy
- 2D NOE
two-dimensional nuclear Overhauser spectroscopy 相似文献
8.
Massimo H. M. Sanago Vern I. Shattuck Judith Strommer 《Plant Cell, Tissue and Organ Culture》1996,45(2):165-168
A simple and rapid pea regeneration procedure was developed. An average of up to 20 shoots formed from hypocotyl explants of cvs. Sugar Ann and Patriot cultured on Murashige and Skoog basal medium supplemented with 0.5 or 1.0 M thidiazuron (N-phenyl-N-1,2,3-thiadiazol-5-ylurea). Hypocotyls of Puget and Sugar Daddy did not respond. Regenerated shoots rooted rapidly when cultured on Murashige and Skoog basal medium containing either 2.0 M -naphthaleneacetic acid or 1.0–2.0 M indole-3-butyric acid. Seeds were harvested from regenerated plants after only 9–11 weeks.Abbreviations BAP
6-benzyladenine
- 2,4-d
2,4-dichlorophenoxy acetic acid
- GA3
gibberellic acid
- IBA
indole-3-butyric acid
- MS
Murashige and Skoog (1962) medium
- NAA
-naphthaleneacetic acid
- TDZ
thidiazuron (N-phenyl-N-1,2,3-thiadiazol-5-ylurea) 相似文献
9.
In this study, we investigate the effects of endothelin-1 (ET-1) and insulin on the cellular activity of protein kinase FA/glycogen synthase kinase-3 (kinase FA/GSK-3) in rat adipocytes. The cellular activity of kinase FA/GSK-3 is inhibited to 50% of control within 30 min when cells are treated with 1 nM ET-1 at 37°C; in addition, significant inhibition to 60% of control is observed at as low as 1 pM ET-1. Conversely, ET-1 at concentrations up to 1 nM has no direct effect on purified kinase FA/GSK-3 in vitro. Immunoblotting analysis further reveals that the protein level of this kinase is not significantly changed when treated with 1 nM ET-1 for 30 min. Similar to ET-1, insulin as low as 10 nM can also induce inactivation of kinase FA/GSK-3 to 50% of control in adipocytes when processed under identical conditions. Most importantly, when treated with both insulin and ET-1, the activity of kinase FA/GSK-3 can be decreased only to 50% of control. Taken together, the results provide initial evidence that ET-1 and insulin may regulate this important multisubstrate/multifunctional protein kinase in a common signaling pathway in cells. 相似文献
10.
An enzyme releasing phosphocholine from glycerophosphocholine was purified to apparent homogeneity based upon SDS-PAGE. The enzyme was liberated from lyophilized bovine myelin by differential detergent extraction and final purification was accomplished with Q-Sepharose Fast Flow chromatography yielding an apparently homogenous protein. The molecular mass based upon PAGE was approximately 14 kDa. The enzyme was also capable of releasing p-nitrophenol from p-nitrophenyl-phosphocholine. Maximal activity was obtained with 0.2 mM ZnCl2 or 1 mM CoCl2. p-Nitrophenylphosphocholine and phosphocholine were competitive inhibitors of glycerophosphocholine hydrolysis with Ki's of 0.028 mM and 0.03 mM respectively. Glycerophosphocholine and phosphocholine were competitive inhibitors of p-nitrophenylphosphocholine hydrolysis with Ki's of 0.5 mM and 1.75 mM respectively.Abbreviations SDS-PAGE
sodium dodecylsulfate polyacrylamide gel electrophoresis
- GPC
glycerophosphocholine
- pNPPC
p-nitrophenylphosphocholine
- OG
octyl--glucoside
- PMSF
phenylmethylsulfonylfluoride
- CNPase
23-cyclic nucleotide 3-phosphodiesterase 相似文献
11.
V. M. Sponsel 《Planta》1986,168(1):119-129
The stem growth in darkness or in continuous red light of two pea cultivars, Alaska (Le Le, tall) and Progress No. 9 (le le, dwarf), was measured for 13 d. The lengths of the first three internodes in dark-grown seedlings of the two cultivars were similar, substantiating previous literature reports that Progress No. 9 has a tall phenotype in the dark. The biological activity of gibberellin A20 (GA20), which is normally inactive in le le geno-types, was compared in darkness and in red light. Alaska seedlings, regardless of growing conditions, responded to GA20. Dark-grown seedlings of Progress No. 9 also responded to GA20, although red-light-grown seedlings did not. Gibberellin A1 was active in both cultivars, in both darkness and red light. The metabolism of [13C3H]GA20 has also been studied. In dark-grown shoots of Alaska and Progress No. 9 [13C3H]GA20 is converted to [13C3H]GA1, [13C3H]GA8, [13C]GA29, its 2-epimer, and [13C3H]GA29-catabolite. [13C3H] Gibberellin A1 was a minor product which appeared to be rapidly turned over, so that in some feeds only its metabolite, [13C3H]GA8, was detected. However results do indicate that the tall growth habit of Progress No. 9 in the dark, and its ability to respond to GA20 in the dark may be related to its capacity to 3-hydroxylate GA20 to give GA1. In red light the overall metabolism of [13C3H]GA20 was reduced in both cultivars. There is some evidence that 3-hydroxylation of [13C3H]GA20 can occur in red light-grown Alaska seedlings, but no 3-hydroxylated metabolites of [13C3H]GA20 were observed in red light-grown Progress. Thus the dwarf habit of Progress No. 9 in red light and its inability to respond to GA20 may be related, as in other dwarf genotypes, to its inability to 3-hydroxylate GA20 to GA1. However identification and quantification of native GAs in both cultivars showed that red-light-grown Progress does contain native GA1. Thus the inability of red light-grown Progress No. 9 seedlings to respond to, and to 3-hydroxylate, applied GA20 may be due to an effect of red light on uptake and compartmentation of GAs.Abbreviations AMO-1618
2-isopropyl-4-(trimethylammonium chloride)-5-methylphenyl piperidine-1-carboxylate
- cv.
cultivar
- GC-MS
gas chromatography-mass spectrometry
- GA(n)
gibberellin A(n)
- HPLC
high-pressure liquid chromatography 相似文献
12.
Summary Short oligocytidylates can act as templates for the self-condensation of guanosine 5-phosphorimidazolide. In the absence of a catalytic metal ion or in the presence of Pb2+ a noticeable template effect is already observed with the dimer and the yield of long oligomers reaches a plateau with a hexamer template. Short templates give oligomers longers than the template length. The products are predominantly 2-5 linked for the Pb2+-catalyzed reaction while mixed linkages are observed in the uncatalyzed reaction.In the presence of Zn2+, a template effect is first observed with the pentamer and is maximal by the heptamer. The products are predominantly 3-5 linked. Oligomers shorter than or as long as the template are obtained in substantial yield, and longer products in much lower yields.Abbreviations G
Guanosine
- Gp
guanosine 2(3)-phosphate
- pG
guanosine 5-phosphate
- Gp!
guanosine cyclic 2,3-phosphate
- ImpG
guanosine 5-phosphorimidazolide
- ImpG*
[8-14C]-guanosine 5-phosphorimidazolide
- pGp
5-phosphoguanosine 2(3)-phosphate
- G2pG
guanylyl-[2-5]-guanosine
- G3pG
guanylyl-[3-5]-guanosine
- ImpGpG
5-phosphorimidazolide of GpG
- (pG)n (n = 2,3)
oligomers of pG
- GppG
P1, P2-diguanosine 5-diphosphate
- GppGpG
5-[guanosine 5-pyrophosphate] of GpG
- NH2pG
guanosine 5-phosphoramidate
- (pG)4+
tetramer and higher oligoguanylates with 5 terminal phosphate
- oligo(G)
oligoguanylate
- Cp
cytidine 2(3)-phosphate
- Cp!
cytidine cyclic 2,3-phosphate
- (Cp)n–1 Cp! (n= 2,3,4)
oligocytidylates terminated by 5-OH groups and 2,3-cyclic phosphates
- oligo(C)
oligocytidylate
- poly(C)
polycytidylic acid
- poly(U)
polyuridylic acid
- poly(C,G)
random copolymer of C and G
- BAP
bacterial alkaline phosphatase (E. coli)
- EDTA
ethylenediaminetetraacetic acid
- Rf
chromatographic mobility 相似文献
13.
Arabidopsis consensus intron sequences 总被引:7,自引:0,他引:7
We have analysed 998 Arabidopsis intron sequences in the EMBL database. All Arabidopsis introns to adhere to the :GU...AG: rule with the exception of 1% of introns with :GC at their 5 ends. Virtually all of the introns contained a putative branchpoint sequence (YUNAN) 18 to 60 nt upstream of the 3 splice site. Although a polypyrimidine tract was much less apparent than in vertebrate introns, the most common nucleotide in the region upstream of the 3 splice site was uridine. Consensus sequences for 5 and 3 splice sites and branchpoint sequences for Arabidopsis introns are presented. 相似文献
14.
M. Hossain M. R. Karim R. Islam O. I. Joarder 《Plant Cell, Tissue and Organ Culture》1993,34(2):199-203
A protocol for organogenesis from nucellar explants excised from fertilized ovules of immature fruits of Aegle marmelos Corr. was developed. Adventitious buds were initiated on Murashige and Skoog's (MS) medium containing various combinations of 6-benzyladenine (BA), -naphthalene-acetic acid (NAA), 3-indoleacetic acid and gibberellic acid. Medium containing 4.4 m BA and 2.7 M NAA produced the maximum number of adventitious buds per explant. Shoots were elongated by transferring explants with shoot buds to medium with a low concentration of BA (0.44 M). Rooting of in vitro-regenerated shoots was obtained in half-strength MS medium with 4.9 M indole-3-butyric acid. This is the first report of plant regeneration from nucellar explants of A. marmelos.Abbreviations BA
benzyladenine
- IAA
indoleacetic acid
- IBA
indolebutyric acid
- NAA
naphthaleneacetic acid
- GA3
gibberellic acid 相似文献
15.
Kojima C Kawashima E Sekine T Ishido Y Ono A Kainosho M Kyogoku Y 《Journal of biomolecular NMR》2001,19(1):19-31
The sugar conformation of a DNA decamer was studied with proton-proton 3J coupling constants. Two samples, one comprising stereospecifically labeled 2-R-2H for all residues and the other 2-S-2H, were prepared by the method of Kawashima et al. [J. Org. Chem. (1995) 60, 6980–6986; Nucleosides Nucleotides (1995) 14, 333–336], the deuterium labeling being highly stereospecific 99% for all 2-2H, 98% for 2-2H of A, C, and T, and 93% for 2-2H of G). The 3J values of all H1-H2 and H1-H2 pairs, and several H2-H3 and H2-H3 pairs were determined by line fitting of 1D spectra with 0.1–0.2 Hz precision. The observed J coupling constants were explained by the rigid sugar conformation model, and the sugar conformations were found to be between C3-exo and C2-endo with m values of 26° to 44°, except for the second and 3 terminal residues C2 and C10. For the C2 and C10 residues, the lower fraction of S-type conformation was estimated from JH1H2 and JH1H2 values. For C10, the N–S two-site jump model or Gaussian distribution of the torsion angle model could explain the observed J values, and 68% S-type conformation or C1-exo conformation with 27° distribution was obtained, respectively. The differences between these two motional models are discussed based on a simple simulation of J-coupling constants. 相似文献
16.
Photoinhibition of photosynthesis represents a mechanism for the long-term regulation of photosystem II 总被引:19,自引:0,他引:19
The obligate shade plant, Tradescantia albiflora Kunth grown at 50 mol photons · m–2 s–1 and Pisum sativum L. acclimated to two photon fluence rates, 50 and 300 mol · m–2 · s–1, were exposed to photoinhibitory light conditions of 1700 mol · m–2 · s–1 for 4 h at 22° C. Photosynthesis was assayed by measurement of CO2-saturated O2 evolution, and photosystem II (PSII) was assayed using modulated chlorophyll fluorescence and flash-yield determinations of functional reaction centres. Tradescantia was most sensitive to photoinhibition, while pea grown at 300 mol · m–2 · s–1 was most resistant, with pea grown at 50 mol · m–2 · s–1 showing an intermediate sensitivity. A very good correlation was found between the decrease of functional PSII reaction centres and both the inhibition of photosynthesis and PSII photochemistry. Photoinhibition caused a decline in the maximum quantum yield for PSII electron transport as determined by the product of photochemical quenching (qp) and the yield of open PSII reaction centres as given by the steady-state fluorescence ratio, FvFm, according to Genty et al. (1989, Biochim. Biophys. Acta 990, 81–92). The decrease in the quantum yield for PSII electron transport was fully accounted for by a decrease in FvFm, since qp at a given photon fluence rate was similar for photoinhibited and noninhibited plants. Under lightsaturating conditions, the quantum yield of PSII electron transport was similar in photoinhibited and noninhibited plants. The data give support for the view that photoinhibition of the reaction centres of PSII represents a stable, long-term, down-regulation of photochemistry, which occurs in plants under sustained high-light conditions, and replaces part of the regulation usually exerted by the transthylakoid pH gradient. Furthermore, by investigating the susceptibility of differently lightacclimated sun and shade species to photoinhibition in relation to qp, i.e. the fraction of open-to-closed PSII reaction centres, we also show that irrespective of light acclimation, plants become susceptible to photoinhibition when the majority of their PSII reaction centres are still open (i.e. primary quinone acceptor oxidized). Photoinhibition appears to be an unavoidable consequence of PSII function when light causes sustained closure of more than 40% of PSII reaction centres.Abbreviations Fo and Fo
minimal fluorescence when all PSII reaction centres are open in darkness and steady-state light, respectively
- Fm and Fm
maximal fluorescence when all PSII reaction centres are closed in darkand light-acclimated leaves, respectively
- Fv
variable fluorescence
- (Fm-Fo)
under steady-state light con-ditions
- Fs
steady-state fluorescence in light
- QA
the primary,stable quinone acceptor of PSII
- qNe
non-photochemical quench-ing of fluorescence due to high energy state
- (pH); qNi
non-photochemical quenching of fluorescence due to photoinhibition
- qp
photochemical quenching of fluorescence
To whom correspondence should be addressedThis work was supported by the Swedish Natural Science Research Council (G.Ö.) and the award of a National Research Fellowship to J.M.A and W.S.C. We thank Dr. Paul Kriedemann, Division of Forestry and Forest Products, CSIRO, Canberra, Australia, for helpful discussions. 相似文献
17.
Summary Soluble lead salts and a number of lead-containing minerals catalyze the formation of oligonucleotides from nucleoside 5-phosphorimidazolides. The effectiveness of lead compounds correlates strongly with their solubility. Under optimal conditions we were able to obtain 18% of pentamer and higher oligomers from ImpA. Reactions involving ImpU gave smaller yields.Abbreviations A
adenosine
-
U
uridine
-
Im
imidazole
-
MeIm
1-methyl-imidazole
-
EDTA
ethylenediaminetetraacetic acid
-
pA
adenosine 5-phosphate
-
pU
uridine 5-phosphate
-
Ap
adenosine cyclic 2:3-phosphate
-
ATP
adenosine 5-triphosphate
-
AppA
P1,P2-diadenosine 5-diphosphate
-
pNp (N = A,U)
nucleotide 2(3), 5-diphosphate
-
ImpA
adenosine 5-phosphoreimidazolide
-
ImpU
uridine 5-phosphorimidazolide
-
A
2pA
adenylyl-[25]-adenosine
-
A
3pA
adenylyl-[35]-adenosine
-
pA
2pA
5-phospho-adenylyl-[25]-adenosine
-
pA
3pA
5-phospho-adenylyl-[35]-adenosine
-
pUpU
5-phospho-uridylyl-uridine
-
pApU
5-phospho-adenylyl-uridine
-
pUpA
5-phospho-uridylyladenine
-
(pA)n (n, 2,3,4,)
oligoadenylates with 5 terminal phosphate
-
ImpApA
5-phosphorimidazolide of adenylyl adenosine
-
(pA)
5+
pentamer and higher oligoadenylates with 5 terminal phosphate
-
(Ap)nA (n = 2,3,4)
oligoadenylates without terminal phosphates
In the following we do not specify the nature of the internucleotide linkageIn the following we do not specify the nature of the internucleotide linkage 相似文献
18.
Summary Exogenous gibberellic acid, A3 (GA3) inhibits phytochrome mediated betacyanin synthesis in seedlings of Amaranthus caudatus. The growth retardants, -chloroethyl-trimethylammonium chloride (CCC), 'isopropyl-4-(triethylammonium chloride)-5-methylphenyl piperidine carboxylate (AMO 1618) and tributyl-2,4,-dichlorobenzylphosphonium chloride (phosphon D) enhance pigment synthesis. Retardant stimulation of pigment synthesis is overcome by GA3 application. Besides lowering endogenous GA levels the retardants inhibit protein synthesis by as much as 25%. Retardant inhibition of protein synthesis is not overcome by GA3. The results suggest that amaranthin synthesis in Amaranthus caudatus can be directly controlled by endogenous GA. GA3 has no effect on kinin induced dark pigment synthesis. Kinins, however, do not overcome GA3 inhibition of pigment synthesis in the light.Abbreviations AMO 1618
2, 'isopropyl-4-(triethylammonium chloride)-5-methylphenyl piperidine carboxylate
- CCC
-chloroethyltrimethylammonium chloride
- GA3
Gibberellic acid, A3
- Phosphon D
tributyl-2,4,-dichlorobenzylphosphoninm chloride 相似文献
19.
Neurosteroids are endogenous Central Nervous System (CNS) compounds which act mainly by allosteric modulation of the GABAA receptor complex. The presence of a 3-hydroxyl group and a 5-hydrogen atom have been found to be essential structural requirements for biological activity in mammals. In the present work we report the enhancing activity on [3H]GABA binding to its receptor sites in chick optic lobe produced by progesterone metabolites 3-hydroxy,5-pregnan-20-one (3,5-P) and 3-hydroxy,5-pregnan-20-one (3,5-P). Both steroids were found able to enhance [3H]GABA binding along ontogeny, displaying a similar profile at early developmental stages, while in adulthood 3,5-P had greater potency (EC50 0.22 M) and enhancing effect (Emax: 122%). In adult synaptic membranes, the two compounds displayed a complex interaction with the GABAA receptor, disclosed by a Schild plot with slope below one and an incomplete displacement of 3,5-P by its 3,5 isomer. Such complexity could be related to the steroidogenic profile in avian CNS, with 5-reduced progesterone metabolites present since early development, while 3,5-P is found only in adulthood. Bearing in mind differences between avian and mammalian steroidogenic profiles and the relevance of 5-steroids in early avian development, we propose that 3,5-P, instead of the classical potent 3,5-steroids, may be the endogenous modulator of GABAergic activity in developing avian brain. 相似文献
20.
Peter M. Chandler 《Planta》1988,175(1):115-120
The slender mutant of barley resembles a normal barley plant treated with high doses of gibberellic acid (GA3). Expression of GA3-regulated and abscisic acid (ABA)-regulated mRNAs was studied in the endosperm and roots of mutant and wild-type (WT) plants.Production of -amylase (EC 3.2.1.1) by WT embryoless half-grains was dependent on the presence of GA3, and was prevented by ABA. In contrast, -amylase was produced by half-grains of the slender mutant in the absence of added GA3, although it was still reduced by ABA. The spectrum of -amylase mRNAs in slender embryoless half-grains incubated in the absence of added GA3 was the same as in WT endosperm half-grains incubated in the presence of GA3. These results indicate that the endosperm of the slender mutant exhibits similar properties to WT endosperm treated with GA3.In roots the expression of an ABA-inducible mRNA was similar in slender and WT seedlings either treated with exogenous ABA or exposed to dehydration. This result, and the effect of ABA on -amylase production by the endosperm, indicate that the slender plants retain sensitivity to ABA.Abbreviations ABA
abscisic acid
- AMV
avian myeloblastosis virus
- GA
gibberellin
- GA1
gibberellin A1
- GA3
gibberellic acid
- WT
wild-type 相似文献