Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0162871 (abdominal aortic aneurysm)
 8,664 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two experiments were conducted to determine the effects of essential amino acid deficiencies on several immunological variables in male broiler chickens. Essential amino acids were classified into five groups as follows: S-containing amino acids (SAA; methionine + cysteine), aromatic amino acids (AAA; phenylalanine + tyrosine), branched-chain amino acids (BCAA; isoleucine + leucine + valine), arginine plus lysine (Arg + Lys), and other essential amino acids (OEAA; glycine + serine + histidine + threonine + tryptophan). Chickens were fed ad libitum from 10 to 24 d of age on a control diet or amino-acid-deficient diets formulated to contain each amino acid group at 50% and 16% (Expt 1) at 50% (Expt 2) of the recommended requirements (National Research Council, 1984). Effects of feed consumption on immune responses were also considered by setting pair-feeding (Expt 1) or restricted-feeding (Expt 2) groups fed on the control diet. In Expt 1, changes in lymphoid organ weights varied with the type and degree of deficiency of amino acid groups, with BCAA deficiency markedly decreasing weights. The haemagglutinin titres against sheep erythrocytes did not change in any amino-acid-deficient chickens except that the titres were lower in chickens fed on the 50%- and 16%-BCAA diets as compared with their pair-fed counterparts. In Expt 2, the splenocyte proliferative response to concanavalin A was higher in the chickens fed on the BCAA- and Arg + Lys-deficient diets and lower in chickens fed on the SAA- and AAA-deficient diets than the control chickens, independent of feed consumption. These results suggest that the effects of specific amino acid deficiencies on immune responses cannot be generalized, and that BCAA have the greatest potential to modulate immune responses among the amino acids in chickens.
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PMID:Effects of dietary essential amino acid deficiencies on immunological variables in broiler chickens. 1085 3

Shared molecular genetic characteristics other than DNA and protein sequences can provide excellent sources of phylogenetic information, particularly if they are complex and rare and are consequently unlikely to have arisen by chance convergence. We have used two such characters, arising from changes in mitochondrial genetic code, to define a clade within the Platyhelminthes (flatworms), the Rhabditophora. We have sampled 10 distinct classes within the Rhabditophora and find that all have the codon AAA coding for the amino acid Asn rather than the usual Lys and AUA for Ile rather than the usual Met. We find no evidence to support claims that the codon UAA codes for Tyr in the Platyhelminthes rather than the standard stop codon. The Rhabditophora are a very diverse group comprising the majority of the free-living turbellarian taxa and the parasitic Neodermata. In contrast, three other classes of turbellarian flatworm, the Acoela, Nemertodermatida, and Catenulida, have the standard invertebrate assignments for these codons and so are convincingly excluded from the rhabditophoran clade. We have developed a rapid computerized method for analyzing genetic codes and demonstrate the wide phylogenetic distribution of the standard invertebrate code as well as confirming already known metazoan deviations from it (ascidian, vertebrate, echinoderm/hemichordate).
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PMID:Changes in mitochondrial genetic codes as phylogenetic characters: two examples from the flatworms. 1102 35

The flatworm mitochondrial genetic code, which has been used for all species of the Platyhelminthes, is mainly characterized by AUA codon for isoleucine, AAA codon for asparagine and UAA codon for tyrosine. In eight species of cestodes (Echinococcus multilocularis, Echinococcus granlosus, Taenia solium Taenia saginata, Taenia hydatigena, Taenia crassiceps, Hymenolepis nama and Mesocestoides corti), the cytochrome c oxidase subunit I (COI) genes were partially sequenced to verify this genetic code. Comparison of the COI-encoding nucleotide sequences with those of human, sea urchin, fruit fly, nematode and yeast indicated that the assignments of AUA and AAA codons are adequate for cestodes. In addition, the nucleotide sequences of ATPase subunit 6 (ATP6) gene and its flanking region were compared to examine initiation and stop codons. In the related species of T. solium and T. saginata, the deduced amino acid sequences of ATP6 were homogeneous; however, the conversion of initiation codon AUG into GUG was observed in T. saginata. We also found the similar conversion in T. crassiceps. The C-terminal sequences of putative ATP6 proteins were highly conserved among the eight species and the stop codon UAG was altered to UAA in all Taenia species. The features of the gene-junctional region between NADH dehydrogenase subunit 4 (ND4) and glutamine tRNA (tRNAGln) genes also supported that UAA serves as a stop codon. Based on these results, we propose that the flatworm mitochondrial code should be modified for cestodes, particularly, in an initiating methionine codon (GUG) and a terminating codon (UAA).
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PMID:Mitochondrial genetic code in cestodes. 1116 47

A recent association study suggested that the His113 variant of microsomal epoxide hydrolase (mEPHX) may confer a risk for development of emphysema, presumably by increasing susceptibility to smoking injury. Before considering a possible role of this enzyme in pulmonary disease, we attempted to characterize the genetic polymorphism further. The Tyr/His113 polymorphism within exon 3 of mEPHX was initially examined in 62 healthy individuals by conventional methods involving polymerase chain reaction (PCR)-based determination of a restriction fragment length polymorphism (RFLP). Genomic nucleotide sequences, including the polymorphic site and the downstream primer sequence, were further analyzed in 95 unrelated, healthy Japanese volunteers by single-stranded conformation polymorphism (SSCP) analysis and direct sequencing. Genotyping by the first method (PCR-RFLP) revealed that the allelic distribution in our test population apparently deviated from Hardy-Weinberg equilibrium. Sequence analysis showed that a synonymous nucleotide substitution, AAG to AAA (Lys119), was located just within the published primer site. The AAA at codon 119 was present only in alleles with Tyr113, and its frequency reached 0.31 in our panel of 190 Japanese alleles. This substitution potentially hampered PCR amplification because of the nucleotide mismatch, with the result that the frequency of the Tyr113 variation was underestimated. The frequency of His113, a possible emphysema susceptibility allele of the mEPHX gene, was thus overestimated when human DNA samples were genotyped in the conventional way. Depending on the population(s) tested, this anomaly could represent a pitfall for PCR-based association studies.
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PMID:Overestimated frequency of a possible emphysema-susceptibility allele when microsomal epoxide hydrolase is genotyped by the conventional polymerase chain reaction-based method. 1128 20

I(f), a diastolic depolarizing current activated by hyperpolarization, is a key player in cardiac pacing. Despite the fact that I(f) has been known for over 20 years, the encoding genes, namely HCN1 to 4, have only recently been identified. Functional data imply that different HCN isoforms may coassemble to form heteromeric channel complexes, but little direct evidence is available. Subunit stoichiometry is also unknown. Although the pore region of HCN channels contains the glycine-tyrosine-glycine (GYG) signature motif found in K+-selective channels, they permeate both Na+ and K+. In the present study, we probed the functional importance of the GYG selectivity motif in pacemaker channels by replacing this triplet in HCN1 with alanines (GYG(349-351)AAA or HCN1-AAA). HCN1-AAA did not yield functional currents; coexpression of HCN1-AAA with wild-type (WT) HCN1 suppressed normal channel activity in a dominant-negative manner (55.2+/-3.2%, 68.3+/-4.3%, 78.7+/-1.6%, 91.7+/-0.8%, and 97.9+/-0.2% current reduction at -140 mV for WT:AAA cRNA ratios of 4:1, 3:1, 2:1, 1:1, and 1:2, respectively) without affecting gating (steady-state activation, activation and deactivation kinetics) or permeation (reversal potential) properties. HCN1-AAA coexpression, however, did not alter the expressed current amplitudes of Kv1.4 and Kv2.1 channels, indicating that its suppressive effect was channel-specific. Statistical analysis reveals that a single HCN channel is composed of 4 monomeric subunits. Interestingly, HCN1-AAA also inhibited HCN2 in a dominant-negative manner with the same efficacy. We conclude that the GYG motif is a critical determinant of ion permeation for HCN channels, and that HCN1 and HCN2 readily coassemble to form heterotetrameric complexes.
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PMID:Dominant-negative suppression of HCN1- and HCN2-encoded pacemaker currents by an engineered HCN1 construct: insights into structure-function relationships and multimerization. 1208 64

The Escherichia coli strain WP2uvrA is widely used in general mutagenicity screening tests because of its high sensitivity to many kinds of mutagens and it serves as a supplement to the standard Salmonella typhimurium tester strains. In contrast to Salmonella His(+) revertants, E.coli Trp(+) revertants have not been characterized at the molecular level. In this study we found that in the trpE65 allele of WP2uvrA the triplet that codes for the fourth amino acid from the N-terminus of anthranilate synthetase was an ochre stop codon (TAA) instead of a glutamine codon (CAA). In spontaneous Trp(+) revertants the ochre codon had been changed to glutamine (CAA), lysine (AAA), glutamic acid (GAA), leucine (TTA), serine (TCA) or tyrosine (TAC, TAT). Since tryptophan prototrophy could also be restored by ochre suppressor mutations at the anticodon sites in the genes for tRNA(Glu) (glnU), tRNA(Lys) (lysT) and tRNA(Tyr) (tyrT, tyrU), the Trp(+) reversion system with E.coli WP2uvrA detected five types of base substitutions, A.T-->T.A, A.T-->C.G, A.T-->G.C, G.C-->A.T and G.C-->T.A. About 30-50% of Trp(+) revertants induced by N-ethyl-N'-nitro-N-nitrosoguanidine, captan and angelicin plus UVA irradiation were attributable to reversion at the trpE65 ochre locus; the others were attributable to suppressor mutations. In contrast, almost all revertants induced by N-methyl-N'-nitro-N-nitrosoguanidine, 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone and furylfuramide were caused by suppressor mutations. Thus, the high mutagen sensitivity of WP2uvrA is due to several target sites consisting of A.T base pairs (trpE65, lysT) and G.C base pairs (glnU, tyrT, tyrU).
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PMID:Characterization of Trp(+) reversions in Escherichia coli strain WP2uvrA. 1211 Jun 27

Integration of cytochrome b(5) (b5), a tail-anchored protein located in the endoplasmic reticulum (ER) membrane, into the membrane was studied. Mutation of three amino acids, -Leu-Met-Tyr, at the carboxy-terminal end of the transmembrane segment of b5 to alanines resulted in localization of the mutated protein, b5LMY/AAA, in the cytosol as well as in the ER membrane. When an N-glycosylation site was introduced at the carboxy-terminal end of b5LMY/AAA, a substantial amount of the glycosylated form of the mutant protein was recovered in the cytosol fraction. A portion of the mutant protein recovered in the ER was released from the membrane by incubation with the cytosol fraction, but no further release was observed in the second incubation, suggesting that b5 is present in two different states, loosely-bound and firmly-integrated forms, in the ER membrane. These results suggest that b5 is integrated into the ER membrane via the loosely bound state, in which the carboxy-terminal end of the molecule is inserted into the luminal side of the vesicle but is easily translocated back to the cytosol, and that the three amino acids are important for conversion of the loosely-bound state to the firmly-integrated state.
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PMID:Integration of cytochrome b5 into endoplasmic reticulum membrane: participation of carboxy-terminal portion of the transmembrane domain. 1276 Nov 89

In a postmortem exploratory study, we examined whether specific amino acid abnormalities associated with liver diseases in vivo may also be detected in human brain samples obtained at clinical autopsies. The branched-chain amino acids (BCAA: valine, leucine, isoleucine) were decreased in the group of patients with liver diseases compared with the control group, whereas the aromatic amino acids (AAA: phenylalanine, tyrosine) were increased. However, the ranges overlapped significantly and were not statistically different. The molar ratio BCAA/AAA was determined to be 1.92 in the collection of patients with liver diseases compared with 2.27 in the control group. In patients with liver disease, ornithine concentrations in the brain appeared significantly decreased whereas glutamine was significantly increased. No significant difference was found in the brain concentrations of proline. Amino acid analysis may contribute to the understanding of pathophysiological mechanisms of liver disease, which are discussed, and may supplement the postmortem diagnosis.
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PMID:Brain amino acid abnormalities in liver disease--a postmortem study. 1464 Feb 89

The Gag proteins of a number of different retroviruses contain late or L domains that promote the release of virions from the plasma membrane. Three types of L domains have been identified to date: Pro-Thr-Ala-Pro (PTAP), Pro-Pro-X-Tyr, and Tyr-Pro-Asp-Leu. It has previously been demonstrated that overexpression of the N-terminal, E2-like domain of the endosomal sorting factor TSG101 (TSG-5') inhibits human immunodeficiency virus type 1 (HIV-1) release but does not affect the release of the PPPY-containing retrovirus murine leukemia virus (MLV), whereas overexpression of the C-terminal portion of TSG101 (TSG-3') potently disrupts both HIV-1 and MLV budding. In addition, it has been reported that, while the release of a number of retroviruses is disrupted by proteasome inhibitors, equine infectious anemia virus (EIAV) budding is not affected by these agents. In this study, we tested the ability of TSG-5', TSG-3', and full-length TSG101 (TSG-F) overexpression, a dominant negative form of the AAA ATPase Vps4, and proteasome inhibitors to disrupt the budding of EIAV particles bearing each of the three types of L domain. The results indicate that (i) inhibition by TSG-5' correlates with dependence on PTAP; (ii) the release of wild-type EIAV (EIAV/WT) is insensitive to TSG-3', whereas this C-terminal TSG101 fragment potently impairs the budding of EIAV when it is rendered PTAP or PPPY dependent; (iii) budding of all EIAV clones is blocked by dominant negative Vps4; and (iv) EIAV/WT release is not impaired by proteasome inhibitors, while EIAV/PTAP and EIAV/PPPY release is strongly disrupted by these compounds. These findings highlight intriguing similarities and differences in host factor utilization by retroviral L domains and suggest that the insensitivity of EIAV to proteasome inhibitors is conferred by the L domain itself and not by determinants in Gag outside the L domain.
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PMID:Late domain-dependent inhibition of equine infectious anemia virus budding. 1469 4

Threshold collision-induced dissociation of M(+)(AAA) with Xe is studied using guided ion beam tandem mass spectrometry. M(+) include the alkali metal ions Na(+) and K(+). The three aromatic amino acids are examined, AAA = phenylalanine, tyrosine, or tryptophan. In all cases, endothermic loss of the intact aromatic amino acid is the dominant reaction pathway. The threshold regions of the cross sections are interpreted to extract 0 and 298 K bond dissociation energies for the M(+)-AAA complexes after accounting for the effects of multiple ion-neutral collisions, internal energy of the reactant ions, and dissociation lifetimes. Density functional theory calculations at the B3LYP/6-31G level of theory are used to determine the structures of the neutral aromatic amino acids and their complexes to Na(+) and K(+) and to provide molecular constants required for the thermochemical analysis of the experimental data. Theoretical bond dissociation energies are determined from single-point energy calculations at the B3LYP/6-311++G(3df,3pd) level using the B3LYP/6-31G geometries. Good agreement between theory and experiment is found for all systems. The present results are compared to earlier studies of these systems performed via kinetic and equilibrium methods. The present results are also compared to the analogous Na(+) and K(+) complexes to glycine, benzene, phenol, and indole to elucidate the relative contributions that each of the functional components of these aromatic amino acids make to the overall binding in these complexes.
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PMID:Cation-pi interactions: structures and energetics of complexation of Na+ and K+ with the aromatic amino acids, phenylalanine, tyrosine, and tryptophan. 1552 80


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