Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0271742 (AAA)
 3,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Low-frequency restriction fragment analysis of more than 100 strains of the genus Frankia showed that restriction enzyme DraI (recognition site, TTT'AAA) gave rise to large DNA fragments (200 to 1,500 kb), which, when they were subjected to cluster analysis, reflected the host plants from which the strains were isolated. Our results support the conclusions of Lalonde and his colleagues (M. Lalonde, L. Simon, J. Bousquet, and A. Seguin, p. 671-680, in H. Bothe, F. J. de Bruijn, and W. E. Newton, ed., Nitrogen Fixation: Hundred Years After, 1988; P. Normand, P. Simonet, and R. Bardin, Mol. Gen. Genet. 213:238-246, 1988) and Fernandez et al. (M. P. Fernandez, H. Meugnier, P. A. D. Grimont, and R. Bardin, Int. J. Syst. Bacteriol. 39:424-429, 1989) that various biochemical and genomic analyses can give rise to groupings of Frankia strains that are consistent with the host plants from which the strains are isolated and that the resulting groups may form a basis for defining Frankia species.
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PMID:Low-frequency restriction fragment analysis of Frankia strains (Actinomycetales). 135 77

A newly composed amino acid solution, which contained a 30% branched-chain amino acid (BCAA), and a standard amino acid solution containing 22.6% BCAA were used for total parenteral nutrition following operation of the digestive organs. Their nutritional effects were evaluated by surgical stress (thoracotomy group or non-thoracotomy group) according to the two steps of amino acid doses (1.2g/kg/day administration group or 1.6g/kg/day group). 1. No significant differences could be recognized in an improvement in the serum proteins following administration of BCAA-enriched solution either in the thoracotomy or in the non-thoracotomy group. 2. An improvement in BCAA/AAA molar ratio was seen on the plasma aminogram following administration of BCAA-enriched solution both in the thoracotomy and in the non-thoracotomy groups. 3. No improvement in nitrogen balance following administration of BCAA-enriched solution could be found in the thoracotomy group, while its improving trend was recognized in the non-thoracotomy group treated with 1.6g/kg/day of the amino acid. 4. Neither in the thoracotomy nor in the non-thoracotomy group any significant inhibition of the excreted volumes of urinary 3-methylhistidine could be recognized.
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PMID:[A study on amino acid solutions for postoperative parenteral nutrition--evaluation in terms of surgical stress, amino acid composition and its doses]. 250 94

The object of this study was to determine of aminoacids and sugar contents of T. verrucosum mycelium and of homologous purified trichophytin Tv-GP. The analysis of aminoacids contents was performed by ion-exchange chromatography on Czechoslovak analyser (type AAA-881) in acid and alkaline hydrolizates. Sugar were identified on gas chromatograph (PYE-105) by Sawerdeker and Sloneker technique. Seventeen identical aminoacids were determined in mycelium and trichophytin, but some quantity differences were observed. In mycelium there was 40.8% aminoacid nitrogen and 59.2% aminosaccharide nitrogen. In trichophytin, however, 93.5% nitrogen originated from aminoacids and only 6.5% from aminosaccharides. In both analized materials hexoses dominated: mannose, glucose and galactose. Besides trace quantities of D-glycero-D-mannoheptose, L-glycero-D-mannoheptose and L-glycero-D-glucoheptose were identified.
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PMID:[Amino acid and carbohydrate levels in Trichophyton verrucosum and homologous purified trichophytin]. 350 16

The aims of this study were: 1. the assessment of the nitrogen balance (NB) in both compensated and encephalopathic cirrhotics, 2. the evaluation of the efficacy of a new therapeutic approach: amino acid solutions enriched with branched chain (BCAA) but poor in aromatic (AAA) amino acids. Solutions containing only BCAA were also employed: 42 cirrhotics were divided into the following groups: 1st group (26 cases), cirrhosis without hepatic encephalopathy (HE); 2nd group (16 cases), cirrhosis with HE. Six patients (23%) in the 1st group showed a positive NB at the beginning; 20 (77%) were negative; 18 of them were fed an oral diet (0.8 g protein/kg/day; 35 cal/kg/day) as a result of which they were brought into a positive NB within 5 days (from - 7.38 +/- 0.95 to + 3.67 +/- 0.46 g N/24 h). In two cases the diet failed to give a positive NB, so it was replaced by a BCAA enriched solution infusion (NB raised from - 1.0 +/- 5.4 g N/24 h). Patients in the 2nd group were put on total parenteral nutrition (TPN); two cases receiving glucose alone achieved a positive NB only when BCAA enriched solutions were added (from - 4.0 to + 3.0 g N/24 h). Four patients treated for 3 days with BCAA alone did not achieve a positive NB; in these cases likewise, BCAA enriched solutions were added in order to achieve a positive NB (from - 0.8 to + 4.2 g N/24 h); all 14 cases treated from the beginning with glucose + BCAA enriched solutions became positive, on average, within 5 days (from - 4.82 +/- 0.89 to + 3.15 +/- 0.61 g N/24 h). In addition to the NB, other parameters (blood ammonia, BCAA/AAA ratio, blood urea, electroencephalograms) and clinical symptoms were beneficially influenced by these solutions.
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PMID:Negative nitrogen balance in cirrhotics. (A correct therapeutic approach). 729 72

The ZraR (HydG) protein is a 441-amino-acid protein with three functional domains and is homologous to the general nitrogen-regulatory protein NtrC that regulates nitrogen assimilation in many bacteria. The AAA and DNA-binding domains (residues 141-441) of the ZraR protein from Salmonella typhimurium were crystallized using the sitting-drop vapour-diffusion method. X-ray diffraction data from the native crystal have been collected to 3.0 A resolution. Initial phasing was successfully performed by the SIRAS method using derivativatized crystals soaked in 1 mM ethylmercuric phosphate. Preliminary structural analysis shows the presence of a hexamer in the asymmetric unit. Model building is in progress.
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PMID:X-ray crystallographic characterization and phasing of an NtrC homologue. 1292 4

Magnetic susceptibilities of spin-1/2 systems of orthorhombic and higher crystal symmetries have been numerically investigated while taking possible anisotropy in the coupling constants along different crystal axes into account. The work relies on the magnon-based theory of ferromagnetic (FM) and antiferromagnetic (AFM) crystal systems of types FFF, AFF, AAF, and AAA [J. Chem. Phys. 111, 9009 (1999)]. The AAF crystal, in particular, shows interesting changes in the temperature dependence of magnetic susceptibility when the ferromagnetic exchange coupling constant is varied. We especially show that the susceptibility anomalies of molecular crystals fit naturally within the framework of the extended magnon-theoretical formalism, and do not necessarily imply a FM --> AFM or a reverse phase transition. A real system, molecular crystal of 2,4,6-triphenylverdazyl (2,4,6-TPV), has been investigated here. It was previously interpreted as an AAF system from observed susceptibility data [Tomiyoshi et al., Phys. Rev. B 49, 16031 (1994)]. The trend of the temperature dependence of magnetic susceptibility studied in the present work also indicates that the crystal belongs to the AAF category with a less prominent FM exchange coupling constant. To reinforce our conclusions, we have adopted a two-pronged strategy. First, the geometry of the 2,4,6-TPV monomer has been optimized here by ab initio unrestricted Hartree-Fock (UHF) calculations using the STO-3G basis set. The optimized geometry is almost planar. A subsequent calculation has been carried out with the phenyl rings twisted out of the plane of the nitrogen atoms. The STO-3G optimized geometry, and the same geometry except for the twisted phenyl rings, have been used to perform ab initio coupled-cluster (UCCSD-T) calculations with the same basis, and UHF as well as density-functional (UB3LYP) calculations using the 6-31G basis set. The calculated data can easily rationalize the twists while the species remains in crystal. The magnetic category of the crystal has been unambiguously confirmed as AFA from ab initio UHF and UB3LYP calculations of the total energy in different spin states of dimers and trimers along the crystal axes. The computed energy values, however, fail to yield accurate estimates of the exchange coupling constants Ja, Jb, and Jc, because the latter are on the order of 1kBK corresponding to energy differences on the order of 10(-6) hartree between different spin states. In the second approach, the observed features of the susceptibility minimum and maximum have been used to determine the best values of the exchange coupling constants from the theoretical formulas for an anisotropic AFA crystal. The AFM (Ja and Jc) and FM (Jb) exchange coupling constants and the Neel temperature (TN) found from this analysis correspond to Ja + Jc = -1.05 kBK, Jb = 1.35 kBK, and TN = 1.75 K. The calculated J values significantly differ from those estimated from a linear Heisenberg chain model, but generate a susceptibility versus temperature graph that mimics the experimental plot.
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PMID:On the variation of magnetic susceptibility of a molecular crystal with temperature: the 2,4,6-triphenylverdazyl system. 1526 78

Transcriptional activation by the E.coli NtrC protein can occur via DNA looping between a DNA-bound activator and the target sigma(54) RNA polymerase. NtrC forms an octamer on DNA that is capable of binding two DNA molecules. Its ATPase activity is required for open complex formation. Geometric requirements for activation were assessed using a library of DNA bending sequences created by random ligation of A-tract oligonucleotides, as well as several designed sequences. Thirty random or designed sequences with a variety of DNA lengths and bending geometries were cloned in plasmids, and the library was used to replace the spacer between the NtrC binding sites and the core glnAp2 promoter. The activity of each promoter construct under nitrogen limitation was determined in vivo, in a lambda phage lacZ reporter system integrated as a single-copy lysogen to avoid titrating NtrC or polymerase. A wide variety of bending geometries was found to support a similar level of transcriptional activation ( approximately 3-4-fold). Computer modeling of the DNA trajectories suggests that the most inactive promoters have short spacer DNA and the NtrC sites on the opposite side of the helix as the wild-type sites; otherwise, the loop can form effectively. Flexibility and multivalency of the NtrC-Esigma(54) interaction apparently provides substantial independence from DNA stiffness constraints, and in general activation requires less efficient looping than repression. However, none of the random templates were as active as wild-type promoter. Subsidiary activator binding sites in the wild-type were found to be required for full activity, but, surprisingly, these sites could not be functionally replaced by strong binding sites. This suggests that one or more protomers in the NtrC octamer must form and then release contacts with DNA in order to complete the ATPase cycle and act as an AAA(+) activator of the Esigma(54). This dynamic DNA wrapping around the NtrC octamer is proposed to be necessary for efficient activation, and the wrapping may also reduce adventitious activation of other promoters.
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PMID:Geometric and dynamic requirements for DNA looping, wrapping and unwrapping in the activation of E.coli glnAp2 transcription by NtrC. 1532 47

Rhizobium leguminosarum bv. viciae forms nitrogen-fixing nodules on several legumes, including pea (Pisum sativum) and vetch (Vicia cracca), and has been widely used as a model to study nodule biochemistry. To understand the complex biochemical and developmental changes undergone by R. leguminosarum bv. viciae during bacteroid development, microarray experiments were first performed with cultured bacteria grown on a variety of carbon substrates (glucose, pyruvate, succinate, inositol, acetate, and acetoacetate) and then compared to bacteroids. Bacteroid metabolism is essentially that of dicarboxylate-grown cells (i.e., induction of dicarboxylate transport, gluconeogenesis and alanine synthesis, and repression of sugar utilization). The decarboxylating arm of the tricarboxylic acid cycle is highly induced, as is gamma-aminobutyrate metabolism, particularly in bacteroids from early (7-day) nodules. To investigate bacteroid development, gene expression in bacteroids was analyzed at 7, 15, and 21 days postinoculation of peas. This revealed that bacterial rRNA isolated from pea, but not vetch, is extensively processed in mature bacteroids. In early development (7 days), there were large changes in the expression of regulators, exported and cell surface molecules, multidrug exporters, and heat and cold shock proteins. fix genes were induced early but continued to increase in mature bacteroids, while nif genes were induced strongly in older bacteroids. Mutation of 37 genes that were strongly upregulated in mature bacteroids revealed that none were essential for nitrogen fixation. However, screening of 3,072 mini-Tn5 mutants on peas revealed previously uncharacterized genes essential for nitrogen fixation. These encoded a potential magnesium transporter, an AAA domain protein, and proteins involved in cytochrome synthesis.
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PMID:Transcriptomic analysis of Rhizobium leguminosarum biovar viciae in symbiosis with host plants Pisum sativum and Vicia cracca. 1937 75

In this work, a morpho-histological study of banana (Musa spp. cv. Grande Naine [AAA]) embryogenic cell suspensions during cryopreservation and regeneration was performed. It was demonstrated that the regeneration process of somatic embryos originating from cryopreserved cell suspensions was different from that of control cell suspensions. Somatic embryos originating from cryopreserved cell suspensions had a unicellular origin. The regeneration process was modified not only by freezing in liquid nitrogen but also by the plasmolyzing effect of the 0.5 M sucrose solution employed during pretreatment. This result explained the high number of embryonic structures formed on M3 medium, compared with the control. Proembryos blocked at the globular stage could pursue their development when they were plated on new culture medium at a lower density after 30 days of culture on M3 medium. The unicellular origin of somatic embryos produced from cryopreserved cell suspensions offers the prospect of using cryopreservation to select non-chimeral transformed plants.
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PMID:Morpho-histological study of banana (Musa spp. cv. Grande Naine [AAA]) cell suspensions during cryopreservation and regeneration. 2030 95

This study explored if a combined supplementation of GH and IGF-1 had an additive effect on whole body nitrogen economy, energy, substrate and skeletal muscle metabolism following surgical trauma. Patients were randomized to controls (C; n = 10), to GH (0.15 IU/kg/injection) (GH; n = 7) or GH combined with IGF-1 (40 mug/kg/injection) subcutaneously twice a day (GH-IGF-1; n = 9) together with standardized parenteral nutrition. Muscle amino acids, glutathione and the ribosomal pattern reflecting protein synthesis, and nitrogen balance were measured. GH- and GH-IGF-1 groups showed lower urea and higher plasma glucose concentrations. Energy expenditure increased in the GH-group. GH-IGF-1 prevented a decrease in muscle polyribosomes indicating a preserved muscle protein synthesis. In the GH group unaltered BCAA and AAA levels were seen in muscle indicating an unchanged protein breakdown, while the other groups showed increased muscle concentrations postoperatively. Without statistically difference GH marginally improved the nitrogen balance, in terms of higher values, and growth factors improved the nitrogen balance when the shift in urea was taken into account. To conclude, growth factors influences urea metabolism, protein degradation and protein synthesis. There was no clearcut additional effect when combining GH and IGF-1 but the study was probably underpowered to outrule this and effects on nitrogen balance.
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PMID:Effects of growth hormone and insulin-like growth factor-1 on postoperative muscle and substrate metabolism. 2079 57


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