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1.
Zhang Jin-Tun 《Plant Ecology》2002,162(1):23-31
Relationships of vegetation, climate and soils in Shanxi plateau wereanalyzed by use of Canonical Correspondence Analysis (CCA). Shanxi province,located at 34°35–40°43 N, 110°15–114°33 E, was divided into a series of rectangular districts of30 latitude by 20 longitude. Areas of vegetation formations and soil types ineach district were measured carefully using fine grain on the vegetation andsoil maps of Shanxi. Climatic data were mean values of 25 years records in eachdistrict. Three data matrices of climate, vegetation and soil were combined byCCA. The results showed that the distribution of vegetation is closely relatedto the variety of climates and to soils distribution. 相似文献
2.
Summary Nucleoside-5-triphosphates such as 5-ATP and 5-GTP can be produced efficiently and continuously from 3-mononucleotides such as 3-AMP and 3-GMP by a series of processes consisting of two reaction phases using dried cells of Candida sp. N-25-2 (a hydrocarbon assimilating yeast). Moreover, incidentally to the 5-triphosphates, free uracil is yielded almost stoichiometrically from 3-CMP and 3-UMP which, as is well known, are main concomitant products depolymerized from RNA. Uracil is then also available for many usage. 相似文献
3.
Six water bodies in the region of Kangerlussuaq, West Greenland (67° 30 N, 50° 46 W), and four near Ammassalik, East Greenland (65° 36 N, 37° 38 W) were sampled. Sixty-nine taxa (2 Bdelloidea, 67 Monogononta) are reported, forty-six of which represent new records for Greenland. Proales pejleri n. sp. is described. 相似文献
4.
Summary The self-condensation of 2(3)-O-glycyl esters of adenosine, adenosine-5-(O-methylphosphate) and P1, P2-diadenosine-5-pyrophosphate in 6.2 mM solutions at pH 8.0 and -5°C in the presence of 12.5 mM poly(U) yields approximately 3 times as much diketopiperazine as reactions without poly(U). As the concentration of 2(3)-O-(glycyl)-P1, P2-diadenosine-5-pyrophosphate is decreased from 6.2 mM to 1.5 mM the yield of diketopiperazine in the presence of poly(U) decreases slightly from 6.6% to 5.2%, whereas, in the absence of poly(U) the yield of diketopiperazine decreases substantially from 2.4% to 0.75%. The enhanced yield of diketopiperazine that is attributed to the template action of poly(U) is temperature dependent and is observed only at temperatures below 10°C (5°C to -5°C) for 6.2 mM 2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate) and below 23°C (15°C to -5°C) for 6.2 mM 2(3)-O-(glycyl)-P1, P2-diadenosine-5-pyrophosphate. The absence of a template effect at high temperatures is attributed to the melting of the organized helices. The hydrolysis half-lives at pH 8.0 and -5°C of 2(3)-O-(glycyl)-adenosine, 2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate), 2(3)-O-(glycyl)-P1, P2-diadenosine-5-pyrophosphate, and 5-O-(glycyl)-adenosine in the presence of poly(U) are substantially larger than their half-lives in the absence of poly(U). The condensation of 2(3)-O-(glycyl)-adenosine yields 5% of 5-O-(glycyl)-adenosine in the presence of poly(U) compared to 0.7% in the absence of poly(U).Abbreviations DKP
diketopiperazine
- (gly)2
glycylglycine
- (gly)3
glycylglycylglycine
- AppA-gly
2(3)-O-(glycyl)-P1, P2-diadenosine-5-pyrophosphate
- MepA-gly
2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate)
- Ado-2(3)-gly
2(3)-O-(glycyl)-adenosine
- Ado-5-gly
5-O-(glycyl)-adenosine
- Boc-gly
N-tert-butyloxycarbonylglycine
- AppA
P1, P2-diadenosine-5-pyrophosphate
- MepA
adenosine-5-(O-methylphosphate)
- AppA-Boc-gly
2(3)-O-(Boc-glycyl)-P1, P2-diadenosine-5-pyrophosphate
- Ado-5-Boc-gly
5-O-(Boc-glycyl)-adenosine
- Ado-2(3)-Boc-gly
2(3)-O-(Boc-glycyl)-adenosine 相似文献
5.
Purified myelin from fresh calf brain white matter was subfractionated in a discontinuous sucrose gradient; significant recovery of protein and 2,3-cyclic nucleotide 3-phosphohydrolase (CNP) and 5-nucleotidase (5N) activities occurred in all three obtained subfractions, the highest recovery being in the light subfraction; highest 5N and CNP specific activities were in medium myelin. Purified myelin was also subfractionated in a continuous sucrose gradient, with a similar localization of protein; CNP activity and 5N activity maxima suggest that myelin may be a predominant locus of 5N in bovine brain white matter. Freezing of brain white matter caused an increase in protein and in CNP and 5N total activity recoveries in denser myelin subfractions. Cytochemistry showed the reaction product of 5N in the whole myelin fraction to be associated with the innermost, outermost and medial compact myelin layers. Effects of non-ionic detergent (Lubrol WX) on 5N activity were studied, and the results also suggest the intrinsic nature of 5N as an ectoenzyme in myelin membranes. Lubrol WX was viewed as an advisable detergent for the stimulation of myelin 5N activity, but not for the solubilization of this enzyme. 相似文献
6.
Sombutyanuchit P. Suphantharika M. Verduyn C. 《World journal of microbiology & biotechnology》2001,17(2):163-168
Spent brewer's yeast was autolysed and used as a raw material for the preparation of 5-GMP-rich yeast extracts. Malt rootlets were used as a source of 5-phosphodiesterase. The crude enzyme was extracted from malt rootlets and pretreated to inactivate 5-nucleotidase. The optimum pretreatment conditions were heating at 65 °C for 30 min or 70 °C for 7 min. The effects of autolysis time, phosphodiesterase concentration and incubation period on 5-GMP content were examined. The suitable autolysis time was 8 h. The preferable enzyme treatment period was in the range of 8–14 h. Longer autolysis and enzyme incubation periods caused a decrease in the 5-GMP content from 0.7–0.9% (w/w) to 0.2–0.4% (w/w). The 5-GMP content in extracts from debittered and non-debittered yeast was similar. The highest 5-GMP content in yeast extract was 0.93% (w/w), obtained with a phosphodiesterase concentration of 1.6unit/ml of yeast extract (5% solids content). 相似文献
7.
Adenosine-5-triphosphate was synthesized by the phosphorylation of adenosine-5-diphosphate in aqueous solution containing cyanate as a condensing reagent and insoluble calcium phosphate produced from phosphate and calcium chloride. In a similar manner, adenosine-5-diphosphate was synthesized from adenosine-5-monophosphate. When the experiment was carried out in the conditions of 4 °C and pH 5.75, the formation of adenosine-5-diphosphate and adenosine-5-triphosphate from adenosine-5-monophosphate was observed in the yields of 19 and 7%, respectively. The other nucleoside-5-triphosphates were also produced from their respective diphosphates. 相似文献
8.
Plausible prebiotic conditions for the phosphorylation of nucleosides by inorganic phosphate were reported by Lohrmann and Orgel in 1971. This reaction was carried out on heated dry films and promoted by urea. The major products formed were nucleoside-2:3 cyclicPs; 5-NMPs and other derivatives were also formed. Minor modifications of the Lohrmann and Orgel system have resulted in the preferential formation of 5-NMPs. In this modified system a 2-fold preference for phosphorylation of the 5-OH group over the 3(2)-OH group was observed and the formation of other derivatives was minimized. The small amounts of bis compounds that were formed in this system could be quantitatively removed by selective binding to the mineral hydroxylapatite at moderate ionic strengths. It was also discovered that under hydrolytic conditions there was a 3:1 preference for removal of phosphates attached to the 3-OH group over the 5-OH group. A recycling procedure for obtaining additional 5-NMPs from bis compounds and 3-NMPs is proposed. 相似文献
9.
Pre-moult foraging trips and moult locations of Emperor penguins at the Mawson Coast 总被引:2,自引:2,他引:0
The movements of nine breeding adult emperor penguins Aptenodytes forsteri from two colonies, Auster (67° 23S 64° 04E) and Taylor Glacier (67° 28S 60° 54E), were determined by satellite telemetry on their pre-moult foraging trips. While preparing for their annual moult the penguins travelled for 22–38 days and reached distances of up to 618 km from the colony. Six of the nine tracked penguins were followed to three different moult locations all to the west of their breeding colonies and near other known emperor penguins colonies, such as Kloa Point (66°38S, 59°23E) and Fold Island (67°17S, 59°23E). Sea-ice conditions changed throughout the tracking period; as the birds travelled north the sea-ice contracted south. 相似文献
10.
Hans Kleinig Hans Reichenbach Hans Achenbach Jochen Stadler 《Archives of microbiology》1971,78(3):224-233
Summary The carotenoid pigments of the myxobacterium Sorangium compositum were analyzed by chromatographical and chemical techniques and by visible, infra red, and mass spectroscopy. Besides -carotene, neurosporene, torulene, lycopene, and 1,2-dihydro-1-hydroxy--carotene, four new carotenoid glycosides were found. These pigments were identified as 1,2-dihydro-1-hydroxy-torulene glucoside ester (I), 1,2-dihydro-3,1-dihydroxy-torulene glucoside ester (III), 1,2-dihydro-1-hydroxy-torulene rhamnoside (II), and 1,2-dihydro-3,1-dihydroxytorulene rhamnoside (IV).Fifth communication on the carotenoids of myxobacteria. Fourth communication see Arch. Mikrobiol. 76, 364–380 (1971). 相似文献
11.
The cleavage of adenosine-5-monophosphate (5-AMP) and guanosine-5-monophosphate (5-GMP) by Ce4+ and lanthanide complex of 2-carboxyethylgermanium sesquioxide (Ge-132) in acidic and near neutral conditions was investigated by NMR , HPLC and measuring the liberated inorganic phosphate at 37°C and 50°C. The results showed that 5-GMP and 5-AMP was converted to guanine (G), 5-monophosphate (depurination of 5-GMP), ribose (depurination and dephosphorylation of 5-GMP), phosphate and adenine (A), 5-monophosphate (depurination of 5-AMP), ribose (depurination and dephosphorylation of 5-AMP), phosphate respectively by Ce4+. In presence of lanthanide complexes, 5-GMP and 5-AMP were converted to guanosine (Guo) and phosphate and adenosine (Ado) and phosphate respectively. The mechanism of cleaving 5-GMP and 5-AMP is hydrolytic scission 相似文献
12.
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
13.
R. Lohrmann 《Journal of molecular evolution》1975,6(4):237-252
Summary When solutions of nucleoside 5-phosphates and trimetaphosphate are dried out at room temperature, nucleoside 5-polyphosphates are formed. The Mg++ ion shows a superior catalytic function in this reaction when compared with other divalent metal ions. Starting with nucleoside 5-phosphates, Mg++ and trimetaphosphate, the predominant products in the nucleoside 5-polyphosphate series pnN are p4N, p7N and P10N. Nucleoside 5-diphosphates yield p5N and p8N, nucleoside 5-triphosphates give p6N and p9N. The prebiological relevance of these reactions is discussed.Abbreviations Pn (n = 1,2,3,)
linear polyphosphate containing n phosphate residues
- P3!
trimetaphosphate
- A
adenosine
- U
uridine
- dA
2-dexyadenosine
- T
thymidine
- PnN
nucleoside 5-polyphosphate containing n phosphate residues, e.g. with N = A and n = 4
- p4A
adenosine 5-tetraphosphate 相似文献
14.
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
15.
Summary 2-Amino-2-deoxyuridine reacts efficiently with nucleoside 5-phosphorimidazolides in aqueous solution. The dinucleoside monophosphate analogues were obtained in yields exceeding 80% under conditions in which little reaction occurs with the natural nucleosides.In a similar way, the 5-phosphorimidazolide of 2-amino-2-deoxyuridine undergoes self-condensation in aqueous solution to give a complex mixture of oligomers.The phosphoramidate bond in the dinucleoside monophosphate analogues is stable for several days at room temperature and pH 7. The mechanisms of their hydrolysis under acidic and alkaline conditions are described.Abbreviations A
adenosine
- C
cytidine
- G
guanosine
- U
uridine
- T
thymidine
- UN
3
2-azido-2-deoxyuridine
- UNH
2
2-amino-2-deoxyuridine
- ImpA
adenosine 5-phosphorimidazolide
- ImpU
uridine 5-phosphorimidazolide
- ImpUN
3
2-azido-2-deoxyuridine 5-phosphorimidazolide
- ImpUNH
2
2-amino-2-deoxyuridine 5-phosphorimidazolide
- pA
adenosine 5-phosphate
- pU
uridine 5-phosphate
- pUN
3
2-azido-2-deoxyuridine 5-phosphate
- pUNH
2
2-amino-2-deoxyuridine 5-phosphate
- UpA
uridylyl-[35]-adenosine
- UpU
uridylyl-[35]-uridine
- UNpA
adenylyl-[52]-2-amino-2-deoxy-uridine
- UNpU
uridylyl-[52]-2-amino-2-deoxyuridine (pUN)n n=2,3,4 [25]-linked oligomers of pUNH
2 poly(A) polyadenylic acid
- Im
imidazole
- MeIm
l-methylimidazole 相似文献
16.
Karl-Heinz Schmidt Heidrun Berressem Karl Georg Berressem und Marianne Demuth 《Journal of Ornithology》1985,126(1):63-71
Zusammenfassung In der Umgebung von Schlüchtern (50°21 N, 09°31 E) und im Stadtbereich Frankfurts (50°08 N, 08°38 E) wurden in mehreren Untersuchungsgebieten seit 1971 bzw. seit 1977 von Oktober/November bis Februar/März regelmäßige nächtliche Kontrollen von 1121 Nistkästen durchgeführt, und zwar in einzelnen Jahren in 3tägigen, wöchentlichen, 14tägigen und monatlichen Abständen. Für eine weitgehend vollständige Erfassung der relativ stabilen Population genügten monatliche Kontrollen. Bei nur einer Winterkontrolle wurde der Bestand erheblich unterschätzt: bei alten betrug der Schätzfehler mindestens 25 %, bei jungen mindestens 45 %. Kohlmeisen reagierten auf nächtliche Kontrollen mit einem Wechsel des Übernachtungsortes. Erst bei Kontrollabständen von 3 Tagen mied ein Teil der Population die Nistkästen. Regelmäßige Nachtkontrollen können zum Verständnis bestandsregulierender Prozesse wie Zu- und Abwanderung, Ansiedlung, Ortstreue und Wintermortalität beitragen.
Studies on Great Tits (Parus major) during winter — possibilities and limits of nocturnal checks
Summary 1121 nest boxes were regularly checked during night from October/November until February/March in the area of Schlüchtern (50°21 N, 09°31 E) since 1971 and since 1977 in the area of Frankfurt (50°08 N, 08°38 E). During that time the checking was done in three-day, weekly, bi-weekly and monthly intervals. A single monthly checking was sufficient for an extensive and complete estimation of the relative stable population. By only one winter checking the population was considerably underestimated: the estimation error was at least 25 % in old and at least 45 % in young . Great Tits reacted to night checking by changing their nocturnal roosting place. A portion of the population will keep clear of the nest boxes when checking is done in three-day intervals. It is being discussed as to what extent regular night checking contributes to the understanding of population regulating processes such as migration, settlement, site fidelity of native birds and winter mortality.相似文献
17.
S. Suzuki T. Kamakura K. Tadokoro F. Takeuchi Y. Yukiyama T. Miyamoto 《International journal of biometeorology》1988,32(2):129-133
A point process model is suitable for analysis of a sequence of binary variables, each of which may be dependent on the preceeding one. This model was used for analysis of the correlation between the state of the atmosphere and the presence or absence of asthmatic symptom known from diaries in which a day was divided into four parts. The diaries were kept during summer and autumn of a year by 19 adult and 12 child patients in Sapporo (43°03 N, 141°20 E), 39 adult and 20 child patients in Tokyo (35°41 N, 139°46 E), and 26 adult and 18 child patients in Naha (26°14 N, 127°41 E).Low temperature and decrease in temperature significantly related to the asthmatic symptom during the seasons. No reversions on correlations as to temperature were observed among places, between the adult and the child, and before and after taking in effects of the preceding symptom and/or the circadian rhythm. Some correlations relating to humidity or to barometric pressure, on the other hand, reversed from place to place, from the adult to the child, and from before to after taking in the effects.Availability of this model for further study on the correlation between the air with contents and the asthmatic symptom is shortly discussed. 相似文献
18.
19.
Summary Amino acids are activated by reaction with adenosine 5-phosphorimidazolide in aqueous imidazole buffers. If adenosine 5-(O-methylphosphate), an analogue of the 3-terminus of t-RNA is present, 2(3)-O-aminoacyladenosine 5-(O-methylphosphate) is formed. Fifteen percent of this compound accumulated at pH 5.8, but less was formed at higher pHs. The highest efficiency of utilization of ImpA attained in our experiments was about 24%. Analogous reactions occured with several other amino acids, including a number that have functional side-chains.Abbreviations pA
adenosine 5-monophosphate
- MepA
adenosine-5-(O-methylphosphate)
- ImpA
adenosine-5-phosphorimidazolide
- A
adenosine
- MepA-ala
2(3)-O-alanyl-adenosine-5-(O-methylphosphate)
- ala-N-pA
adenylyl-(5 N)-alanine
- ImH
imidazole
- DKP
diketopiperazine 相似文献
20.
Ahlert Schmidt 《Archives of microbiology》1977,112(3):263-270
Crude extracts of Rhodospirillum rubrum catalyzed the formation of acid-volatile radioactivity from (35S) sulfate, (35S) adenosine-5-phosphosulfate, and (35S) 3-phosphoadenosine-5-phosphosulfate. An enzyme fraction similar to APS-sulfotransferases from plant sources was purified 228-fold from Rhodospirillum rubrum. It is suggested here that this enzyme is specific for adenosine-5-phosphosulfate, because the purified enzyme fraction metabolized adenosine-5-phosphosulfate, however, only at a rate of 1/10 of that with adenosine-5-phosphosulfate. Further, the reaction with 3-phosphoadenosine-5-phosphosulfate was inhibited with 3-phosphoadenosine-5-phosphate whereas this nucleotide had no effect on the reaction with adenosine-5-phosphosulfate. For this activity with adenosine-5-phosphosulfate the name APS-sulfotransferase is suggested. This APS-sulfotransferase needs thiols for activity; good rates were obtained with either dithioerythritol or reduced glutathione; other thiols like cysteine, 2-3-dimercaptopropanol or mercaptoethanol are less effective. The electron donor methylviologen did not catalyze this reaction. The pH-optimum was about 9.0; the apparent K
m for adenosine-5-phosphosulfate was determined to be 0.05 mM with this so far purified enzyme fraction. Enzyme activity was increased with K2SO4 and Na2SO4 and was inhibited by 5-AMP. These properties are similar to assimilatory APS-sulfotransferases from spinach and Chlorella.Abbreviations APS
adenosine-5-phosphosulfate
- PAPS
3-phosphoadenosine-5-phosphosulfate
- 5-AMP
adenosine-5-monophosphate
- 3-AMP
adenosine-3-monophosphate
- 3-5-ADP
3-phosphoadenosine-5-phosphate (PAP)
- DTE
dithiorythritol
- GSH
reduced glutathione
- BAL
2-3-dimercaptopropanol 相似文献