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1.
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   

2.
A sulfotransferase isolated from the Cyanobacterium Synechococcus 6301 was found to be specific for 3-phosphoadenosine-5-phosphosulfate (PAPS). The molecular weight of this transferase has been estimated on a Sephadex-G-100 column to be about 58,000. The K m for PAPS was determined to be 20 M. The pH optimum was 8.0. The thiol dithioerythritol was needed for activity; other thiols such as glutathione, cysteine, or mercaptoethanol did not catalyze this reaction. The transferase, however, could not react directly with the thiol. A heat-stable factor was needed in this reaction. This factor was purified by conventional techniques and its molecular weight was determined on a Sephadex-G-50 column to be about 11,500. The factor showed normal Michaelis-Menten behavior toward the PAPS-sulfotransferase. It has been identified as thioredoxin. The tranferase was inhibited by 3-5-ADP and 2–5-ADP; all other adenine-containing nucleotides such as 2-AMP, 3-AMP, 5-AMP, ADP, and c-AMP did not influence this reaction.Abbreviation PAPS 3-phosphoadenosine-5-phosphosulfate  相似文献   

3.
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   

4.
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   

5.
Species of the genus Actinostola are known for high variability of features. Anatomy, histology and cnidae of type specimens of five species from South America and Antarctica originally described as members of Actinostola and one species of Stomphia were compared to specimens of Actinostola chilensis collected during this study. None of these traditionally used features clearly distinguish the examined Actinostola species. I therefore propose new distinctive taxonomic features, including in vivo and in situ data. I provide an emended diagnosis of the genus Actinostola and a revised list of its species. I accept the synonymy of A. excelsa, A. pergamentacea and A. intermedia with A. crassicornis, and reject the synonymy of A. chilensis with A. crassicornis and A. intermedia. I re-describe A. chilensis in detail, including in situ information. Specimens of A. chilensis inhabit exposed positions of rocky substrate from 22 m depth down in south Chilean fjords between Puerto Montt (41°3535S, 72°53W) and Puyuhuapi (44°3136S; 72°326W); the most conspicuous features are its relatively large size, bright-orange colour, smooth, tough column and numerous and clearly entacmaeic tentacles.Electronic Supplementary Material  Supplementary material is available in the online version of this article at The publisher regrets that during copy-editing of this article the names of the authors of species were styled incorrectly. Therefore, it was decided to publish this erratum which, due to the nature of the paper, contains the whole original article, but now with the names of species authors styled correctly.The online version of the original article can be found at  相似文献   

6.
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   

7.
Evidence is presented that a poly(U) template selectively favors the oligomerization of the activated, 3–5 pyrophosphate-linked dimer pdAppdAp, in comparison with the 3–3 and 5–5 linked dimers. In the absence of poly(U), the 5–5linked dimer is the most reactive, and chains are formed which are more than 60 monomer units in length.Nucleic Acid-Like Structures V. For the previous paper in this series see Visscher and Schwartz (1988).  相似文献   

8.
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   

9.
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   

10.
Random coil proton chemical shifts of deoxyribonucleic acids   总被引:2,自引:0,他引:2  
Sixteen 17-nucleotide DNA sequences have been used to determine the sequence effect on random coil DNA proton chemical shifts. Based on the proton chemical shifts measured for the central nucleotides in 64 triplets and the correction factors determined for the next nearest neighbor effects, a parameter set has been derived for predicting random coil DNA proton chemical shifts. The root-mean-square deviation (RMSD) between the predicted and the observed aromatic H6/H8 proton chemical shifts of 200 data from 22 random coil DNA sequences was determined to be 0.02 ppm with a correlation coefficient of 0.998. For the H1, H2, H2 and H3 sugar protons, the RMSD values between the predicted and the experimental shifts were found to be 0.02, 0.03, 0.03 and 0.02 ppm, respectively.  相似文献   

11.
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   

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.
Ten previously unreported oligosaccharides have been purified from the urines of human subjects using a combination of gel filtration, ion exchange, and thin-layer chromatographies. Their structures were determined by direct probe mass spectrometry, methylation analysis, and proton NMR spectroscopy of the permethylated oligosaccharide alditols.On the basis of composition, the oligosaccharides could be divided into three groups. Five oligosaccharides containing glycerol were characterized as glucosyl1-1glycerol; glucosyl1-1glycerol; galactosyl1-1glycerol; glucosyl-1-1(fucosyl-1-2)glycerol and/or fucosyl-1-1(glucosyl-1-2)glycerol; and glucosyl-1-1(galactosyl-1-2)glycerol or galactosyl-1-1(glucosyl-1-2)glycerol. Four inositol-containing oligosaccharides were characterized as galactosyl1 (fucosyl1)inositol,N-acetylgalactosaminyl1 (fucosyl1)inositol, fucosyl1-2galactosyl1 (N-acetylgalactosaminyl1)inositol and fucosyl1-2galactosyl1-4-N-acetylglucosaminyl1(N-acetylgalactosaminyl1)inositol. Finally, galactosyl1-3(fucosyl1-2)galactosyl1-6galactosyl1-4(fucosyl1-3)glucose, an oligosaccharide with glucose at its reducing end, was tentatively identified. The significance and possible origins of the carbohydrate structures are discussed.  相似文献   

14.
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   

15.
2-d-5-GMP and 2-d-5-AMP bind 2 times more strongly to montmorillonite 22A than do 2-d-5-CMP and 5-TMP. The dinucleotide d(pG)2 forms in 9.2% yield and the cyclic dinucleotide c(dpG)2 in 5.4% yield in the reaction of 2-d-5-GMP with EDAC in the presence of montmorillonite 22A. The yield of d(pC)2 (2.0%) is significantly lower but comparable to that obtained from 5-TMP. The yield of dimers which contain the phosphodiester bond decreases as the reaction medium is changed from 0.2 M NaCl to a mixture of 0.2 M NaCl and 0.075 M MgCl2. A low yield of d(pA)2 was observed in the condensation reaction of 5-ImdpA on montmorillonite 22A. The cyclic nucleotide (3,5-cdAMP) was obtained in 14% yield from 3-ImdpA. The yield of d(pA)2 obtained when EDAC is used as the condensing agent increases with increasing iron content of the Na+-montmorillonite used as catalyst. Evidence is presented which shows that the acidity of the Na+-montmorillonite is a necessary but not sufficient factor for the montmorillonite catalysis of phosphodiester bond formation.  相似文献   

16.
Evidence is presented for complexation of guanosine 5-monophosphate 2-methylimidazolide (2-MeImpG) with polycytidylate (poly(C)) at pH 8.0 and 23°C in the presence of 1.0 M NaCl and 0.2 M MgCl2 in water. The association of 2-McImpG with poly(C) was investigated using UV-vis spectroscopy as well as by monitoring the kinetics of the nucleophilic substitution reaction of the imidazole moiety by amines. The results of both methods are consistent with moderately strong poly(C) · 2-McImpG complexation and the spectrophotometric measurements allowed the construction of a binding isotherm with a concentration of 2-McImpG equal to 5.55 ± 0.15 mM at half occupancy. UV spectroscopy was employed to establish the binding of other guanosine derivatives on poly(C). These derivatives are guanosine 5-monophosphate (5GMP), guanosine 5monophosphate imidazolide (ImpG), and guanosine 5monophosphate morpholidate (morpG). Within experimental error these guanosine derivatives exhibit the same affinity for poly(C) as 2-McImpG.  相似文献   

17.
De Smet  W. H.  Beyens  L. 《Hydrobiologia》1995,(1):29-34
Samples from eight water bodies in the region of Truelove and Sparbo Hardy Lowland, Devon Island (75 ° 30 N, 86 ° 00 W) yielded 70 taxa (4 Bdelloidea, 66 Monogononta) of rotifers, nineteen of which are new records for the Canadian High Arctic.  相似文献   

18.
Zusammenfassung Aus fünf antarktischen Bodenproben von 60°45, 62°14 und 63°24 südlicher Breite wurden in 92 Ansätzen drei niedere Phycomyceten herausgeködert, nämlich Rhizophydium utriculare, Rhizophydium sphaerotheca und Hyphochytrium cf. catenoides. Sie alle sind auch von Standorten mit milderem Klima bekannt und Kosmopoliten.  相似文献   

19.
Structural analogues of the NADP+ were studied as potential coenzymes and inhibitors for NADP+ dependent malic enzyme from Zea mays L. leaves. Results showed that 1, N6-etheno-nicotinamide adenine dinucleotide phosphate ( NADP+), 3-acetylpyridine-adenine dinucleotide phosphate (APADP+), nicotinamide-hypoxanthine dinucleotide phosphate (NHDP+) and -nicotinamide adenine dinucleotide 2: 3-cyclic monophosphate (23NADPc+) act as alternate coenzymes for the enzyme and that there is little variation in the values of the Michaelis constants and only a threefold variation in Vmax for the five nucleotides. On the other hand, thionicotinamide-adenine dinucleotide phosphate (SNADP+), 3-aminopyridine-adenine dinucleotide phosphate (AADP+), adenosine 2-monophosphate (2AMP) and adenosine 2: 3-cyclic monophosphate (23AMPc) were competitive inhibitors with respect to NADP+, while -nicotinamide adenine dinucleotide 3-phosphate (3NADP+), NAD+, adenosine 3-monophosphate (3AMP), adenosine 2: 5-cyclic monophosphate (25AMPc), 5AMP, 5ADP, 5ATP and adenosine act as non-competitive inhibitors. These results, together with results of semiempirical self-consistent field-molecular orbitals calculations, suggest that the 2-phosphate group is crucial for the nucleotide binding to the enzyme, whereas the charge density on the C4 atom of the pyridine ring is the major factor that governs the coenzyme activity.Abbreviations NADP+ 1, N6-etheno-nicotinamide adenine dinucleotide phosphate - NHDP+ nicotinamide-hypoxanthine dinucleotide phosphate - APADP+ 3-acetylpyridine-adenine dinucleotide phosphate - SNADP+ thionicotinamide-adenine dinucleotide phosphate - AADP+ 3-aminopyridine-adenine dinucleotide phosphate - 23NADPc+ -nicotinamide adenine dinucleotide 2: 3-cyclic monophosphate - 3NADP+ -nicotinamide adenine dinucleotide 3-phosphate - 2AMP adenosine 2-monophosphate - 3AMP adenosine 3-monophosphate - 23AMPc adenosine 2: 3 monophosphate cyclic - A adenosine - RuBP ribulose 1,5-bisphosphate - SCF-MO Self-Consistent Field-Molecular Orbitals (method)  相似文献   

20.
Lutein (,-carotene-3,3-diol) is the major carotenoid of the light-harvesting systems of higher plants. Lutein was isolated at 4°C and in complete darkness from the bulk light-harvesting complex of Photosystem II of spinach (LHC IIb) and from BBY particles. Separation using normal-phase HPLC (with 2D detection) in comparison to the authentic isomers (prepared by iodine-sensitised isomerization) showed the presence of a number of geometrical isomers of this xanthophyll in PS II, namely all-trans (the major component); 13-cis, 13-cis and 15-cis-lutein. Iodine-sensitised photo-isomerization of all-trans lutein produced six geometrical isomers of lutein as determined by HPLC. The configuration of five of these isomers was determined by 1H-NMR to be all-trans, 9-cis, 9-cis, 13-cis and 13-cis. In addition, small amounts of another isomer have been tentatively identified to be 15-cis lutein on the basis of its electronic absorption spectrum. The possible functional significance of the presence of cis-isomers of this carotenoid in LHC IIb is discussed.  相似文献   

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