Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A series of three molecular dynamics simulations at 300 K in explicit solvent environments of chloroform, methanol and water has been performed on the pulmonary surfactant lipoprotein, SP-C, comprising several consecutive valine residues in order to investigate the stability of the alpha-helical conformation. Two additional simulations were performed on truncated SP-C with a five-residue N-terminal deletion at 300 K and 500 K in water, the high temperature run in order to increase the rate of peptide denaturation. Indications of destabilization appear in chloroform during 1 ns while the SP-C alpha-helix is remarkably stable during 1 ns in methanol and water. In particular the polyvalyl part comprising residues Val15 to Val21 remains intact even at elevated temperature, and the valines do not disrupt the alpha-helical conformation. The valyl-rotamer sampling is partly restricted. Unfolding takes place successively along the primary sequence starting from the C-terminal end. Factors affecting polypeptide stability in molecular dynamics simulations are addressed. The intrinsic helix-forming tendency of valine residues and its dependence on the sequence context, and the role of the solvent environment in stabilizing or destabilizing an alpha-helical fold, are discussed.
J Mol Biol 1995 Apr 07
PMID:The effect of environment on the stability of an integral membrane helix: molecular dynamics simulations of surfactant protein C in chloroform, methanol and water. 772 32

Adriamycin (AD)-Fe3+ caused the inactivation of Na(+)-, K(+)-ATPase and Ca(2+)-ATPase of erythrocyte membranes during lipid peroxidation. AD-Fe3+ also induced the formation of fluorescent substances from the membranes with lipid peroxidation. The fluorescent substances were little extracted by chloroform-methanol, indicating that they were retained in the membranes. Butylated hydroxytoluene and trolox strongly inhibited both the inactivation of these ATPases and the formation of fluorescent substances with lipid peroxidation. Another antioxidant, vitamin E, slightly prevented the damage of the membranes. However, p-nitrophenyl phosphatase activity and acetylcholine esterase have lower or no susceptibility to the membrane lipid peroxidation. These results indicated that the ATPases were very sensitive to lipid peroxidation and that the membranes were modified during the peroxidation reaction.
Res Commun Mol Pathol Pharmacol 1995 Feb
PMID:Adriamycin-Fe(3+)-induced inactivation of enzymes in erythrocyte membranes during lipid peroxidation. 774 51

Our interest in detecting genotoxic exposure in earthworms led us to isolate high quality DNA from the Eisenia fetida species. For that, we compared a modification of the conventional phenol-chloroform extraction procedure, usually referred to as the Maniatis procedure, to two commercially available kits reportedly eliminating multiple partitions in phenol and chloroform, namely the Qiagen and Nucleon protocols. From the 260 nm optical density values, the commercial kits extracts hinted toward higher DNA recovery with those procedures. However, the 260/280 nm ratios indicated that the quality of the DNA isolated with the modified Maniatis procedure was purer than that isolated with the commercial kits, the latter being most probably contaminated by proteins and/or RNA. The Maniatis procedure was slightly modified by the introduction of a potassium acetate step for protein precipitation and by shortening the proteinase K treatment from 12-18 h to only 2 h. The higher quality of the DNA isolated by phenol-chloroform extraction was confirmed by quantification with the fluorescent 3,5-diaminobenzoic acid assay. Preliminary results suggest that the modified Maniatis procedure herein described is not only applicable for DNA adducts studies using 32P-postlabelling techniques but is also suitable for DNA extraction from other earthworm species such as Lumbricus terrestris.
Mol Cell Biochem 1995 Jan 12
PMID:Isolation of genomic DNA from the earthworm species Eisenia fetida. 775 38

We investigated the metabolism of 26,26,26,27,27,27-hexafluoro-1 alpha,25-dihydroxyvitamin D3 (26,27-F6-1,25(OH)2D3, ST-630) and 1 alpha,25-dihydroxyvitamin (1,25(OH)2D3) in cultured neonatal mouse calvaria to elucidate why ST-630 is more potent than 1,25(OH)2D3 in stimulating bone resorption in organ culture. The metabolites were extracted with ethyl acetate or chloroform/methanol (1:1) from cultured calvaria or medium incubated with [3H]-ST-630 or [3H]-1,25(OH)2D3 for various periods, and separated by high performance liquid chromatography. [3H]-ST-630 in cultured calvaria was converted to [3H]-26,26,26,27,27,27-hexafluoro-1 alpha,23(S),25-trihydroxyvitamin D3(26,27-F6-1,23,25(OH)3D3,ST-232), which stimulated bone resorption equipotently as 1,25(OH)2D3. The amount of [3H]-ST-232 produced in the bone increased with passage of the culture period. In contrast, the amount of [3H]-ST-630 in the bones decreased in the 2 day cultures. In the medium, [3H]-ST-630 was hardly detectable for 2 days. This suggests that ST-630 is metabolized to ST-232 which is retained in the bones. On the other hand, some [3H]-1,25(OH)2D3 was metabolized to inactive forms detectable in the medium. Therefore, the high potency of ST-630 in stimulating bone resorption in organ culture may be associated with a difference between ST-630 and 1,25(OH)2D3 in the mode of metabolism in the cultured bones.
Res Commun Mol Pathol Pharmacol 1994 Nov
PMID:Differences in metabolism between 26,26,26,27,27,27-hexafluoro-1 alpha, 25-dihydroxyvitamin D3 and 1 alpha, 25-dihydroxyvitamin D3 in cultured neonatal mouse calvaria. 788 67

The purpose of this study was to determine the efficiency of semi-nested PCR in detecting hepatitis A virus (HAV) RNA. During a 2-year period (1990-1991), HAV RNA was searched for in shellfish from the French Brittany coasts using cRNA and vRNA probes. In January 1992, at the time of a hepatitis A outbreak, 28 stool samples were collected from infected patients (18 adults, 10 children) with anti-HAV IgM. Four samples from subjects with negative HAV serology were used as negative controls. Nucleic acid amplification (reverse-transcription-semi-nested PCR) was performed to detect HAV in stool. HAV RNA was purified by phenol-chloroform extraction and converted to cDNA using reverse transcriptase (Mu-MLV). After amplification, PCR products were visualized on an ethidium-bromide-stained gel and confirmed by hybridization with a specific digoxigenin-labelled oligoprobe. Samples were also studied by molecular hybridization with cRNA and vRNA probes. After onset of the illness, HAV RNA was detected over a longer time period by semi-nested PCR (16/28) than by hybridization (0/28). Even though biological diagnosis of hepatitis A will continue to rely on the detection of anti-HAV IgM, PCR should be useful in certain clinical cases (diagnosis of relapse) and for epidemiological and environmental monitoring of viruses.
Mol Cell Probes 1994 Apr
PMID:Development of RT-semi-nested PCR for detection of hepatitis A virus in stool in epidemic conditions. 793 9

1. The functional effects of bilirubin:albumin solutions (10:1, mol/mol) on several synaptosomal functions were investigated using rat cortical, striatal, and hippocampal synaptosomes prepared by iso-osmotic Percoll/sucrose gradient centrifugation. 2. Bilirubin (10-80 microM) depolarized synaptosomes in a tetrodotoxin-insensitive manner as assessed by the equilibrium distribution of tetra-[3H]phenylphosphonium. Depolarization induced by bilirubin was of a lesser magnitude than that caused by KCl or veratridine. Steady-state pH gradients across the synaptosomal membrane were determined using the transmembrane distribution of [14C]methylamine. Bilirubin (20-40 microM) did not modify the intracellular pH in physiological buffers. The pigment effected a 0.14 delta pH change when the synaptosomes were suspended in a Ca2+ and Na+ free choline medium containing ouabain. 3. Bilirubin (20-80 microM) had no effect of its own on [7,8-3H] dopamine release from striatal synaptosomes. In contrast, it inhibited the initial rate of synaptosomal uptake of the catecholamine and its intrasynaptosomal content at 10 min. The pigment (20 and 40 microM) reduced the 35 mM KCl-induced release of endogenous acetylcholine from hippocampal synaptosomes by 20 and 36%, respectively. 4. The association of bilirubin with synaptic plasma membrane vesicles was characterized by a chloroform:methanol 2:1 (v/v) extraction method. At total concentrations of 10 to 80 microM bilirubin, the molar percentage of the pigment in synaptic plasma membrane phospholipids was 1-4%. 5. It is proposed that the two main functional consequences of the bilirubin-nerve ending interaction are an impairment of specific membrane-bound neurotransmitter uptake mechanisms and a reduction of the response to depolarizing stimuli. This may be the basis for rapid alterations in synaptic transmission documented in early reversible bilirubin encephalopathy.
Cell Mol Neurobiol 1993 Feb
PMID:Interactions of bilirubin with isolated presynaptic nerve terminals: functional effects on the uptake and release of neurotransmitters. 809 65

Rearrangement of the BCL-2 gene is the molecular consequence of the t(14;18) chromosomal translocation, which is found in approximately 60-90% of follicular lymphomas. To investigate the ability of the polymerase chain reaction (PCR) to detect this rearrangement in fixed-tissue samples, we studied 48 cases of follicular lymphoma using DNA extracted from paired samples of fresh-frozen tissue and formalin-fixed, paraffin-embedded tissue. A standard phenol-chloroform DNA extraction method was used for both types of tissue. Rearrangements of the major breakpoint region (MBR) and minor cluster sequence (MCS) were examined. Three segments of the human beta-globin gene were also amplified to estimate the degree of DNA degradation in the fixed-tissue samples. PCR of fresh-tissue (intact) DNA revealed amplifiable products in 29 of the 48 follicular lymphomas (60%), whereas the fixed-tissue (degraded) DNA studies were positive in 24 (50%). MBR products were detected in 24 fresh-tissue samples, and varied from 80 bp to > 1.5 kb. Twenty of these cases yielded MBR products in the corresponding fixed-tissue DNA, ranging from 80 to 276 bp. Five fresh-tissue and four fixed-tissue samples produced MCS segments that ranged from 340 bp to 1.2 kb. Four of the five samples with no detectable MBR or MCS translocations using degraded DNA had products greater than 1.0 kb in the fresh-tissue studies. A 175-bp segment of the beta-globin gene was amplified in all 29 fixed-tissue samples; a 324 bp fragment was produced in 20 samples (69%), and a 676 bp segment was detected in 13 (45%).(ABSTRACT TRUNCATED AT 250 WORDS)
Diagn Mol Pathol 1993 Dec
PMID:Rearrangement of the BCL-2 gene in follicular lymphoma. Detection by PCR in both fresh and fixed tissue samples. 811 1

Chloroform has been shown to induce hepatocellular carcinomas in female B6C3F1 mice when administered by gavage, but not when given in drinking water. When administered in corn oil at the carcinogenic doses of 238 and 477 mg/kg, chloroform induced necrosis and sustained regenerative cell proliferation in the liver. To investigate the mode of action of tumor induction in the target cells, the ability of chloroform to induce unscheduled DNA synthesis (UDS) was examined in the in vitro and in vivo hepatocyte DNA repair assays. In the in vitro assay, primary hepatocyte cultures from female B6C3F1 mice were incubated with concentrations from 0.01 to 10 mM chloroform in the presence of 3H-thymidine. UDS was assessed by quantitative autoradiography. No induction of DNA repair was observed at any concentration. In the in vivo assay, animals were treated by gavage with 238 and 477 mg/kg chloroform in corn oil. Primary hepatocyte cultures were prepared 2 and 12 hr later, incubated with 3H-thymidine, and assessed for induction of UDS as above. No DNA repair activity was seen at either dose or at either timepoint. These negative results in the target organ are consistent with the concept that neither chloroform nor its metabolites are directly DNA reactive and that the carcinogenicity of chloroform is secondary to induced cytolethality and regenerative cell proliferation.
Environ Mol Mutagen 1994
PMID:Lack of chloroform-induced DNA repair in vitro and in vivo in hepatocytes of female B6C3F1 mice. 814 1

A PCR assay was developed to detect human rhinovirus (HRV) RNA in nasal washings from individuals experimentally infected with HRV-39 or HRV strain Hanks. Total RNA was purified from samples stored in the presence of vanadyl ribonucleoside complex (VRC) by one of two methods: proteinase K digestion followed by multiple extractions with phenol/chloroform (PK-PC); or denaturation with guanidinium thiocyanate followed by one phenol/chloroform extraction (GTC). The limit of detection of HRV in nasal washings spiked with HRV-39 was lower with the GTC method (1 TCID50) than with the PK-PC method. In a study of 31 nasal washings extracted by the PK-PC method, the sensitivity (93%) and negative predictive value (94%) were sub-optimal in comparison to cell culture. In a study of 60 nasal washings extracted by the GTC method, the number of samples positive by PCR (25) exceeded by two the number positive by isolation in cell culture. A GTC-based method for HRV RNA extraction in nasal washings was superior to a proteinase K-phenol/chloroform-based method in regard to sensitivity, consumption of reagents, material and time.
Mol Cell Probes 1993 Oct
PMID:Detection of human rhinovirus RNA in nasal washings by PCR. 826 71

Spatial structures of a chymotryptic fragment C2 (residues 1-71) of bacterioopsin from Halobacterium halobium, solubilized in a mixture of methanol/chloroform (1:1, by vol.) and 0.1 M 2HCO2NH4, or in perdeuterated sodium (2H)dodecyl sulfate (SDS) micelles in the presence of perdeuterated (2,2,2-2H)trifluoroethanol, were determined by two-dimensional and three-dimensional heteronuclear 15N-1H NMR techniques. The influence of (2,2,2-2H)trifluoroethanol on the conformational dynamics of C2 in micelles and the effect of the salt (organic mixture) were studied. Under the best conditions, 1H and 15N resonances of 15N-uniformly enriched protein were assigned in both milieus by homonuclear two-dimensional NOE (NOESY) and two-dimensional total-correlated (TOCSY) spectra and heteronuclear three-dimensional NOESY-multiple-quantum-correlation (HMQC) and TOCSY-HMQC spectra. 651 (organic mixture) and 520 (micelles) interproton-distance constraints, derived from volumes of cross-peaks in two-dimensional NOESY and three-dimensional NOESY-HMQC spectra, along with deuterium exchange rates of amide groups measured in both milieus and 51 HN-C alpha H coupling constants obtained in the case of the organic mixture, were used in the construction of C2 spatial structures. Obtained structures are similar in both milieus and have two right-handed alpha-helical regions stretching from Pro8 to Met32 and Phe42 to Tyr64 (organic mixture), and from Pro8 to Met32 and Ala39 to Leu62 (micelles). In micelles, the second alpha helix is terminated by C-cap Gly63, adopting a conformation characteristic of a left-handed helix. Residues Gly65 to Thr67 from the turn of a right-handed helix. In the isotropic medium of the organic mixture, the C-terminal region of residues 65-71 lacks an ordered structure. Torsion angles chi 1 were unequivocally determined for 18 alpha-helical residues in both milieus. In the isotropic organic mixture and anisotropic micellar system, C2 remains a compact structure with a characteristic size of 3.0-3.5 nm. C2 seems to be present in at least two conformational states, packed and unpacked. Using NMR data, along with the electron cryomicroscopy model of bacteriorhodopsin [Henderson, R., Baldwin, J. M., Ceska, T. A., Zemlin, F., Beckman, E. & Downing, K. H. (1990) J. Mol. Biol. 213, 899-929], we suggested a model for the conformation of C2 in this putative close-packed state. However, no NOE contact between alpha helices was found in either milieu.
 ...
PMID:Three-dimensional structure of (1-71)bacterioopsin solubilized in methanol/chloroform and SDS micelles determined by 15N-1H heteronuclear NMR spectroscopy. 830 23


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