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1.
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   

2.
Ionic relations of aeroponically-grown olive genotypes,during salt stress   总被引:1,自引:1,他引:0  
Two olive (Olea europaea L.) genotypes, Frantoio and Leccino, were exposed to increasing concentrations of NaCl (0-30-60-120 mM) in an aeroponic cultivation system for 60 days. Dry weights and sodium and potassium contents of apical and basal leaves, new and old wood, and roots were measured to determine Na uptake rate, Na translocation rate and K-Na selectivity ratio (SK,Na). Frantoio showed a higher salt resistance than Leccino. Frantoio and Leccino had a similar Na uptake rate, but largely differed for Na translocation to the shoot. Furthermore Frantoio exhibited a higher K-Na selectivity than Leccino at both whole plant level and above all at the level of shoot system. Resistance mechanism of Frantoio is probably related to Na esclusion by roots and to the ability to maintain an appropriate K/Na ratio in actively growing tissues.Research supported by National Research Council of Italy, Special project RAISA.  相似文献   

3.
TNF alpha is required for hypoxia-mediated right ventricular hypertrophy   总被引:1,自引:0,他引:1  
Hypoxia has been shown to activate the pleiotropic cytokine TNF in the lung. TNF in turn, is known to induce pulmonary vasoconstriction. Additional effects of this cytokine in hypoxia mediated cardiopulmonary remodeling are poorly understood. To further evaluate the role of TNF in chronic hypoxia we exposed TNF null (TNF–/–) and wild-type mice to three weeks of hypobaric hypoxia (10% O2). Equivalent erythocytosis (Hematocrit increased by 40%) developed in both genetic backgrounds. In contrast, right ventricular systolic pressure increased in response to three weeks of hypoxia in the wild-type mice ( 75%), yet was unaltered in the TNF–/– mice. Concomitantly right ventricular hypertrophy was attenuated in the TNF–/– mice (35 ± 5% increase) when compared to wild-type mice (124 ± 6% increase p < 0.001, n 20). Interestingly in both strains the lung wet weights increased to a similar degree in response to hypoxia. In conclusion, our data demonstrate that TNF is an integral autocoid in chronic hypoxia mediated right ventricular hypertrophy. Moreover, additional components of cardiopulmonary remodeling may be regulated by TNF signaling as suggested by the negligible right ventricular systolic pressure response to hypoxia in the absence of TNF.  相似文献   

4.
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   

5.
Summary Photoreactive probes for the hydrophobic pocket of the liver fatty acid-binding protein, 11-(5-azido-salicylamido)-undecanoic acid (5 ASU) and its acetyl ester (Ac5 ASU), were synthesized and their interaction with the protein was assessed. Fatty acid-binding proteins are closely related proteins which are abundantly expressed in tissues with active lipid metabolism. A simple model that assumes that the protein possesses a single kind of sites fitted the binding of radioiodinated 5 ASU to L-FABP satisfactorily. The apparent dissociation constant, 1.34×10–7 M, evidenced a slightly higher affinity than that reported for C16–C20 fatty acids. Consistent with the binding curve, 5 ASU effectively competed with palmitic acid for the hydrophobic sites and the effect was nearly complete for concentrations of 1 gmM; oleic acid, in turn, displaced the radiolabelled probe. Irradiation at 366 nm of125I-5 ASU bound to L-FABP caused the covalent cross-linking of the reagent. The amount of radioactivity covalently bound reached a maximum after 2 min thus agreeing with the photo-activation kinetics of the unlabelled compound that evidenced a t1/2 of 31.1 sec. The yield with which probes bound to L-FABP became covalently linked to the protein, appraised after SDS-PAGE of irradiated samples, was estimated as 23 and 26 per cent for 5 ASU and Ac5 ASU respectively. In turn, irradiation of L-FABP incubated with 5ASU or Ac5 ASU resulted in the irreversible loss of about one fourth its ability to bind palmitic acid. Both results, taken together, suggested that the derivatives are linked to the protein through the sites for fatty acids. When cross-linking of125I-5 ASU was performed after incubation with delipidated cytosol and products were analyzed by SDS-PAGE, a band was visualized in a position similar to that of purified L-FABP.Abbreviations FABP Fatty Acid-Binding Protein - L-FABP Hepatic FABP - I-FABP Intestinal FABP - C-FABP Cardiac FABP - 5 ASU-11 (5-azido-salicylamido)-undecanoic acid - Ac5 ASU-11 (O-acetyl-5-azido-salicylamido)-undecanoic acid  相似文献   

6.
In Fuji, the production of ethylene was increased with the addition of AgNO3 and inhibited with the addition of 10 M aminoethoxyvinylglycine (AVG). The addition of 80 M AgNO3 to transformed explants of Fuji cultured on selection medium resulted in increased ethylene production (20 l l–1) at 3 weeks. Under examining the effect of AgNO3 in Fuji, the 40 M AgNO3 showed with higher 33.8% and 6.5% in the efficiency of regeneration and transformation. However, ethylene production in Gala explants treated with 10M AgNO3 (3 l l–1) decreased after 2 weeks compared with the control (5 l l–1). Although the regeneration efficiency of Gala with 10 M AgNO3 was higher (41.1%) than the control (20.1%), there was no significant difference in the transformation efficiency at the same concentration. Shoot regeneration of Fuji and Gala was completely inhibited with 10 M AVG. These results suggest that the addition of AgNO3 affects the efficiency of Agrobacterium-mediated gene transfer in Fuji.Eun Soo Seong, Ill Min Chung- These two Authors Contributed equally to this work  相似文献   

7.
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   

8.
Summary Particle supported biofilms of uniform thickness were generated in an aerobic fluidized-bed reactor with phenol as the carbon source. A method was developed for determining the effective diffusivities of oxygen and phenol using trypan blue, a vital stain as the tracer. The effective diffusivities of oxygen and phenol were found to be 2.72×10–6 cm2/s and 1.12×10–6 cm2/s respectively.Nomenclature Ci initial solute concentration in bulk, g/cm3 - Ct solute concentration in bulk at time t, g/cm3 - C bulk solute concentration at equilibrium, g/cm3 - D molecular diffusivity, cm2/s - D effective diffusivity, cm2/s - Do Dp Dtb molecular diffusivity of oxygen, phenol and trypan blue, cm2/s - Do, Dp, Dtb effective diffusivity of oxygen, phenol and trypan blue, cm2/s - Ds molecular diffusivity of substrate, cm2/s - Ds effective diffusivity of substrate, cm2/s - K partition coefficient - Mt amount of solute in the particle at time t, g - M amount of solute in the particle at equilibrium, g - r particle radius, cm - r bp radius of the particle with biofilm, cm - S substrate concentration, g/cm3 - Sb substrate concentration in bulk, g/cm3 - Si initial substrate concentration, g/cm3 - V1 solute molar volume, cm3/g mol Greek Symbols bf porosity of the biofilm - tortuosity factor  相似文献   

9.
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   

10.
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   

11.
4-Methylumbelliferyl 6-O-benzyl--d-lactoside (6Bn-MU-Lac) and some related compounds were synthesizedvia different selective reactions including phase-transfer glycosylation. Their suitability as substrates for a fluorometric assay of ceramide glycanase (CGase) was evaluated. Among others, the 6Bn-MU-Lac, which is resistant to exogalactosidase, was found to be a suitable substrate for routine assay of the CGase activity. For American leech CGase, theK m value is 0.232 mM at pH 5. Abbreviations: CGase, ceramide glycanase; Gal, galactose; Glc, Glucose; Lac, lactose; MU, 4-methylumbelliferone; MU-Lac, 4-methylumbelliferyl -d-lactoside; bBn-Lac, 6-O-benzyl-lactose; 6Bn-MU-Lac, 4-methylumbelliferyl 6-Obenzyl--d-lactoside; 46Bd-MU-Lac, 4-methylumbelliferyl 4,6-O-benzylidene--d-lactoside; MU-Cel, 4-methylumbellifery -d-cellobioside; 46Bd-MU-Cel, 4-methylumbelliferyl 4,6-O-benzylidene--d-cellobioside; TLC, thin layer chromatography;1H-NMR, proton nuclear magnetic resonance; GSL, glycosphingolipids; CSA, 10-camphorsulfonic acid. See Scheme 1 for chemical structures.  相似文献   

12.
A (13, 14)--glucan 4-glucanohydrolase [(13, 14)--glucanase, EC 3.2.1.73] was purified to homogeneity from extracts of germinated wheat grain. The enzyme, which was identified as an endohydrolase on the basis of oligosaccharide products released from a (13, 14)--glucan substrate, has an apparent pI of 8.2 and an apparent molecular mass of 30 kDa. Western blot analyses with specific monoclonal antibodies indicated that the enzyme is related to (13, 14)--glucanase isoenzyme EI from barley. The complete primary structure of the wheat (13, 14)--glucanase has been deduced from nucleotide sequence analysis of cDNAs isolated from a library prepared using poly(A)+ RNA from gibberellic acid-treated wheat aleurone layers. One cDNA, designated LW2, is 1426 nucleotide pairs in length and encodes a 306 amino acid enzyme, together with a NH2-terminal signal peptide of 28 amino acid residues. The mature polypeptide encoded by this cDNA has a molecular mass of 32085 and a predicted pI of 8.1. The other cDNA, designated LW1, carries a 109 nucleotide pair sequence at its 5 end that is characteristic of plant introns and therefore appears to have been synthesized from an incompletely processed mRNA. Comparison of the coding and 3-untranslated regions of the two cDNAs reveals 31 nucleotide substitutions, but none of these result in amino acid substitutions. Thus, the cDNAs encode enzymes with identical primary structures, but their corresponding mRNAs may have originated from homeologous chromosomes in the hexaploid wheat genome.  相似文献   

13.
Summary Crude cell-free extracts of Anabaena cylindrica synthesized adenosine-5-phosphosulphate (AP35S) and 3-phosphoadenosine-5-phosphosulphate (PAP35S) from 35SO4 2- in the presence of Mg2+, ATP and inorganic pyrophosphatase. Maximum AP35S and PAP35S were produced at pH 7.15 and 8.05, respectively. APS kinase was detected in the supernatant of crude cell-free extracts by a spectrophotometric procedure. ATP-Sulphurylase had an absolute requirement for Mg2+ and less than 30% AP35S was formed when Mg2+ was replaced by either Mn2+ or Co2+. Nucleotide triphosphates other than ATP and 2-deoxyATP were ineffective in this reaction. Maximum enzyme activity was observed at equimolar concentrations of Mg2+ and ATP and excess of either of these was inhibitory. Other nucleotide triphosphates, like GTP, UTP, CTP, TTP, ITP, or 2-deoxyATP also inhibited the enzyme activity. Inhibition by GTP was competitive with respect to ATP. ATP-sulphurylase activity was not affected by cysteine, methionine or glutathione.Abbreviations APS adenosine-5-phosphosulphate - PAPS 3-phosphoadenosine-5-phosphosulphate  相似文献   

14.
Effector-target conjugates, formed by coincubation of lymphokine-activated killer (LAK) cells with either K562 or Daudi cells, were separated from single cells by Percoll sedimentation. The occurrence of various CD molecules (CD3, CD56, CD57, CD16, /-TCR) was compared in both fractions. Only LAK cells expressing the / T cell receptor (TCR) were found in a significantly increased percentage in fractions containing conjugates indicating that /-TCR+ LAK cells were preferably bound to target cells at the time of separation. In order to determine whether /-TCR+ LAK cells also show a preferred killing activity against the targets, cultures enriched with or depleted of /-TCR+ cells were established. Against K562 cells, /-TCR+-enriched cultures showed a greatly reduced killing activity compared to LAK bulk cultures or cultures depleted of /-TCR+ cells. Using Daudi cells as targets the enriched fraction revealed a slightly increased killing activity compared to bulk cultures or depleted fractions. Preincubation of /-TCR+ LAK cells with anti-/ or anti-CD3 mAb resulted in a distinct increase of the killing activity against K562 cells, but in only a slightly enhanced activity against Daudi cells. It is postulated that /-TCR+ LAK cells use the same adhesion mechanism for both targets but that only Daudi cells express a specific ligand for the /-TCR. Occupation of the /-TCR/CD3 complex by mAb, however, seems to substitute for the absent epitope on K562 cells by eliciting stimulatory signals in /-TCR+ LAK cells which, in combination with the binding stimulus, trigger cytolytic activity.This work was supported by the Hartmann-Müller Foundation, Zürich  相似文献   

15.
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   

16.
Summary Suspensions of endocrine pancreas cells were prepared by shaking collagenase-isolated rat islets of Langerhans in calcium-free buffer. When incubated with 1.0 mM substrate at pH 7.4, the cells split,P i from 5-AMP at a rate of 87 nmol/h per g DNA, and from-glycerophosphate at a rate of 25 nmol/h per g DNAK m for 5 AMP was about 54 M. Adenosine or theophylline inhibited the 5-AMP hydrolysis. Homogenization of the cells increased the activity toward 5-AMP by 23% and that toward-glycerophosphate by 115%. Injecting rats with cortisone had no effect on the 5-AMP hydrolysis by whole cells but significantly increased the activity in cell homogenates; the intracellular activity toward 5-AMP was more than doubled by the cortisone treatment. Staining whole islet cells for 5-AMP-splitting activity resulted in a demarcation of the cell periphery in control rats. Cells from cortisone-treated rats showed heavier deposits of reaction product, and their cell periphery did not stand out as clearly. It is suggested that 5-nucleotidase is largely an ectoenzyme in normal rat islet cells. The cells also contain an as yet unidentified intracellular phosphatase that seems to be solely responsible for the increased hydrolysis of 5-AMP in cortisone-treated rats.  相似文献   

17.
The seed storage globulins from sixHelianthus and four hybrids were studied using mono and bidimensional gel SDS electrophoresis (+ 2 mercaptoethanol). The polypeptide composition of each subunit was determined. Different pairs are specifically expressed according to the species studied. Three typical patterns were discriminated. All the studied species exhibit five subunits: two of them are expressed in all the species (11 and 22). The subunit corresponding to the 11 pair is present inH. petiolaris and in the three populations ofH. annuus studied. The 2b2 pair is common toH. annuus andH. argophyllus. H. petiolaris presents two specific 2a2 and 44 pairs andH. annuus a specific 33 pair. InH. argophyllus 11 33 or 44 are never observed but are replaced by 13 and 31 pairs. Some globulins, poorly represented, are of forms but present chains of higher molecular weights (in the range 54–56 kDa). Expressing variations in the banding patterns between these species by the use of a similarity index reveals complete identity between the three populations ofH. annuus. Identity between the twoH. petiolaris studied is also observed.H. annuus andH. argophyllus appear to be closer to each other thanH. petiolaris concerning the seed storage globulins.  相似文献   

18.
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   

19.
Summary The degree of methylation at the 5 and 3 CCGG sequences flanking the variable number of tandem repeat (VNTR) region of the DXS255 locus at Xp11.22 was analysed separately in several haematopoietic cell lineages. The 5 CCGG site on active chromosomes was found to be completely methylated in B and T lymphocytes and granulocytes. Methylation of the 5 site on inactive X chromosomes differed between females (0%–60%), but was consistent in different cell lineages obtained from individual females. In contrast, methylation at the 3 CCGG site on active chromosomes was found to vary in B lymphocytes (40%–100%), whereas complete methylation was found in T lymphocytes and granulocytes. The extent of methylation on inactive X chromosomes was found to differ significantly between B lymphocytes (17%), T lymphocytes (54%) and granulocytes (82%). Thus, methylation at the 5 CCGG site seems to be primarily related to the status of X chromosome inactivation, whereas methylation at the 3 CCGG site is mainly subject to cell-lineage-specific influences.  相似文献   

20.
Summary Ten hairy-cell leukemia patients were treated with interferon (IFN-) at a dose rate of 2 × 106 IU/m2 × 5 days for 4 weeks (induction therapy) and, thereafter, at the same dose three times a week for 11 months (maintenance therapy). The effect of this treatment on serum neopterin, 2-microglobulin, (2–5)oligoadenylate [(2–5)A n ] levels, intracellular (2–5)A n values and human Mx protein synthesis was analysed. There were significant rises in serum neopterin and (2–5)A n levels during both induction and maintenance, whereas 2-microglobulin levels rose only during induction. Rises in intracellular (2–5)A n were documented mainly during induction, but they were not significantly higher than pretherapy values. IFN provoked an increase in human Mx protein synthesis over the entire induction — maintenance period, but was only significantly higher than baseline during induction. All markers proved useful for monitoring the effects of IFN dose schedules, but were not predictive of clinical outcome. Natural killer activity and IFN production, which were initially defective, followed a different trend from that of the other factors studied, in that increases were documented only late in the course of therapy when the disease was already in remission.  相似文献   

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