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

While antibiotics are broadly used in dental and medical therapy, little attention has been directed towards the potential toxic side effects of antibiotics on tissue regeneration. Here we examined the effect of a quinolone antibiotic, pefloxacin (Rhone Poulenc) on rat parotid gland responses to chronic isoproterenol treatment. Groups of rats received injections of isoproterenol to induce glandular growth, saline (controls), pefloxacin, or isoproterenol and pefloxacin in combination. Parotid gland weight decreased significantly after pefloxacin treatment for 7 days as well as inhibiting glandular enlargement provoked by isoproterenol. The same trend was observed for the rates of DNA synthesis, with the incorporation of [3H]-thymidine in isoproterenol/pefloxacin-treated rats reduced to 49% of isoproterenol treatment alone levels. Saline-treated animals were 42% of the rate of [3H]-thymidine incorporation into DNA observed in isoproterenol treated rats. While isoproterenol treatment increased steady-state mRNA levels for fos, jun, myc, src, c-erbB-2, ras and topo II, inclusion of pefloxacin with the isoproterenol regimen blocked these increases. Pefloxacin treatment by itself did not alter proto-oncogene mRNA levels in the parotid gland. Glandular amylase activity was decreased in the pefloxacin treated group, while the combination of isoproterenol with pefloxacin did not decrease glandular amylase levels to the extent of that observed with beta-agonist treatment alone. In acute experiments, pefloxacin significantly decreased the volume of saliva secreted by the parotid gland. These results suggest that quinolone-based antibiotics disturb the secretory function of the parotid gland and can inhibit cell proliferation and regeneration.
Mol Cell Biochem 1996 Dec 06
PMID:Inhibition of rat parotid gland growth response induced by chronic isoproterenol following treatment with quinolone antibiotics. 897 81

The ability of cells to energize their membranes during salt-adaptation as measured by delta pH was studied using the electron spin resonance (ESR) spin probe technique. Salt-adaptated cells have the following features: an increased stability of delta pH across the cytoplasmic membrane and a significantly lower rate of delta pH formation across the thylakoid membrane. Therefore, during salt-adaptation, the cytoplasmic membrane takes over the role of primary energizing membrane from the thylakoid membrane. In contrast to non-adapted cells, delta pH across the thylakoid membrane of salt-grown cells is higher under respiratory than under photosynthetic conditions.
Biochem Mol Biol Int 1996 Dec
PMID:Proton gradients during salt adaptation of Synechococcus. 898 32

We improved the enzyme-linked lectin-binding assay (ELLA) to determine the differences in the carbohydrate chains of corpus, antral, duodenal ant colonic rat mucins. First we have improved the optimal conditions of this assay for mucins; ELLA makes possible the detection of 1.5 ng of hexose in rat gastrointestinal mucins (5-7 ng of mucins). Salt concentrations of several dozens mM are required for mucin coating on the plate. Non-ionic detergents diminish the adsorption of mucins onto the plate. Secondly we tested a set of 8 lectins to compare their binding to the gastrointestinal mucin samples. It is possible to detect crude mucins as well as purified mucins using ELLA. Gastric mucins have less Tn-antigen than duodenal and colonic mucins. Corpus and duodenal mucins have more of the H-type 2 chain than antral and colonic mucins.
Comp Biochem Physiol B Biochem Mol Biol 1997 Feb
PMID:Comparative study of carbohydrate portion of gastrointestinal mucins using enzyme-linked lectin-binding assay (ELLA). 915 80

A novel technique is described for the evaluation of membrane integrity in isolated nuclei. Membrane integrity is assessed by measuring nuclear fragility in response to high salt conditions. Salt-induced disruption of the nuclear membrane is followed by spectrophotometric monitoring of released nucleotides. The assay is based on determining the amount of salt necessary to induce release of 50% of the total pool of releasable nucleotides. This allows semiquantitative comparison of relative nuclear membrane strength or integrity of different samples in response to high salt conditions. In this manner, the effects of altered nuclear membrane composition or metabolism on membrane integrity may be monitored.
Mol Cell Biochem 1997 Jul
PMID:The nuclear membrane integrity assay. 927 36

It is well established that the opioid neuropeptide and dopamine systems are altered following the use of cocaine. However very little information is available about their possible involvement during cocaine abstinence. In the present study, the mRNA expression of the dopamine receptors, D1 and D2, and the opioid peptides, prodynorphin and proenkephalin, were analyzed in the rat striatum using in situ hybridization histochemistry. Saline or cocaine (30 mg/kg, i.p.) were administered to rats once daily for 1 or 10 days. To examine cocaine abstinence, animals were treated for 10 days as described followed by a 10-day drug free period. Acute and intermittent cocaine administration elevated the prodynorphin mRNA expression in the dorsal striatum, consistent with previous reports, while the abstinent phase resulted in a significant reduction of prodynorphin mRNA levels in the ventrorostral striatum. The D1-receptor mRNA was decreased in the caudorostral striatum during cocaine withdrawal, a finding opposite to the increase observed following a single injection of the drug. Proenkephalin and the D2-receptor mRNAs were not altered during cocaine abstinence, though proenkephalin was elevated following acute but not repeated cocaine administration. These results show long-term suppression on prodynorphin and D1-receptor systems in specific striatal populations localized mainly in rostral areas during withdrawal from cocaine.
Brain Res Mol Brain Res 1998 May
PMID:Specific reductions of striatal prodynorphin and D1 dopamine receptor messenger RNAs during cocaine abstinence. 960 9

The Sudan plated lizard (Gerrhosaurus major), previously reported to be an afebrile species, was utilized in a series of experiments to test for various aspects of the acute phase response. Treatment of individuals with the antibiotic Baytril resulted in a slight (0.5 degree C) but significant reduction in mean selected body temperature (MSBT), while treatment with saline did not lower MSBT. Nonantibiotic treatment individuals had depressed plasma iron levels (86.6 +/- 22.4 micrograms Fe 100 ml-1 plasma) and treatment with Baytril produced a significant increase in plasma iron concentration (186.8 +/- 19.5 micrograms Fe 100 ml-1 plasma). Necropsy of randomly selected individuals indicated that animals obtained from the commercial supplier had Aeromonas, Arthrobacter, Pseudomonas and Salmonella infections and antibiotic treatment eliminated these infections. The growth rate of Aeromonas sobria is reduced when the bacteria are grown at 32 degrees C and reduced iron concentration compared to 34.5 degrees C and low iron concentration, which suggests that a fever response may not be beneficial in reducing bacterial growth. Saline injected, bacteria injected and antibiotic injected Gerrhosaurus major have high plasma zinc concentrations compared to the previously studied febrile species, Dipsosaurus dorsalis. This difference suggests that zinc concentrations in afebrile species deserve further study.
Comp Biochem Physiol A Mol Integr Physiol 1998 Jun
PMID:The acute phase response in the Sudan plated lizard, Gerrhosaurus major. 977 12

Bacteriophage T4 provides an important model for the biochemistry and genetics of DNA metabolism. Phage-encoded proteins conduct all essential steps of T4 DNA replication, repair, and recombination. Central to these three processes is the T4 UvsX protein, a member of the filamentous, ATP-dependent class of general recombination enzymes typified by the Escherichia coli RecA protein. Like RecA, UvsX forms presynaptic filaments on single-stranded (ss) DNA, which are the obligatory nucleoprotein intermediates in recombination. Aspects of the T4 presynaptic filament are explored by quantitative characterization of the UvsX-ssDNA interaction using an etheno-derivitized single-stranded DNA molecule, epsilonDNA, whose fluorescence is enhanced by UvsX binding. Studies with this model lattice show that UvsX exhibits a moderate level of cooperativity (omega=100) when binding to epsilonDNA with a binding-site size (n) equal to four nucleotide residues. Salt-stability studies of this complex reveal that the non-hydrolyzable ATP analog, ATPgammaS, induces a high-affinity binding mode that is distinguishable from complexes formed with ADP or in the absence of a nucleotide cofactor. With this new information, both functional relationships between the UvsX and RecA recombinases, and implications for UvsX interactions with the other proteins of the T4 presynaptic filament (UvsY and gp32) may be further explored.
J Mol Biol 1998 Nov 06
PMID:Single-stranded DNA binding properties of the UvsX recombinase of bacteriophage T4: binding parameters and effects of nucleotides. 979 Aug 40

Salt bridges have been proposed to play a crucial role in promoting hyperthermostability in proteins, yet they appear to make little contribution to protein stability at room temperature. The latter point has been rationalized previously on the basis that the association of two charged molecules to form a salt bridge incurs a substantial desolvation penalty, which is seldom completely compensated by favourable interactions within the salt bridge and with the rest of the protein. Here a continuum solvation model is used to investigate how this same argument applies at temperatures more appropriate to hyperthermophiles. The solvation model employed was previously parameterised to reproduce the hydration free energies of neutral and charged amino acid side-chains in the temperature range from 5-100 degreesC. A key result of the previous work was that the hydration free energies of charged side-chains are more adversely affected by increasing temperature than are the hydration free energies of hydrophobic side-chains of identical size and shape (isosteres). As is shown here, a direct consequence of the temperature dependence of the hydration free energies is that at high temperatures the desolvation penalty for formation of a salt bridge is markedly reduced in magnitude. As a result, the argument that relative to hydrophobic isosteres, salt bridges destabilise proteins, may no longer be true at high temperatures. We demonstrate this point first in the setting of a small model system, but then also show that the same argument is likely to carry over to real proteins. We compare three hyperthermophilic proteins with their mesophilic homologues and find that hydration effects preferentially stabilise the hyperthermophiles at high temperatures. When the hydration effects are incorporated into a model for the free energy of folding of the proteins, it is found that in each case, the hyperthermophile is predicted to remain stable to a temperature 20-25 deg.C higher than the corresponding mesophile. Higher thermal stability for the hyperthermophile is obtained even if the mesophile is more stable at room temperature. The results obtained therefore suggest one possible way in which the apparently destabilising effects of salt bridges at room temperature can be reconciled with their increased abundance in hyperthermophilic proteins.
J Mol Biol 1998 Nov 27
PMID:The stability of salt bridges at high temperatures: implications for hyperthermophilic proteins. 981 32

We previously reported evidence for two subpopulations of several classes of steroid receptors that could be distinguished by their requirement of a low molecular weight factor (Mr=700-3000 Da) for binding to nonspecific, calf thymus DNA-cellulose [Cavanaugh, A. H. and Simons Jr., S. S., Journal of Steroid Biochemistry and Molecular Biology, 48, 433-446 (1994)]. This factor appeared to be enriched in (NH4)2SO4 precipitates of nuclear extracts. Using human progesterone receptors (PRs) and biologically active DNA sequences in a modified avidin/biotin-coupled DNA (ABCD) binding assay, we now report a factor-mediated increase in PR binding to specific DNA sites that was indistinguishable from that seen with nonspecific sites. The main advantages of this modified assay are that both kinetic and equilibrium binding of receptor-steroid complexes to DNA can be directly monitored in solution. The ability of either Sephadex G-50 chromatography or sodium arsenite to prevent that binding which is increased by added factor supported the existence of PR subpopulations that are independent of the acceptor DNA sequence. The factor was found, surprisingly, to be low concentrations (> or = 5 mM) of (NH4)2SO4, which anomalously is partially excluded from Sephadex G-10 columns, and can be mimicked by some salts but not sodium arsenite. Kinetic analyses demonstrated that the mechanism of action of salt was to accelerate the rate of binding of PR. Salt also had a much greater effect on the nonspecific binding of PR, such that the ratio of specific to nonspecific DNA binding was greatest at elevated salt concentrations (approximately 75 mM) that afforded submaximal levels of PR binding to specific DNA sites. Further analysis of the DNA-bound receptors revealed that the smaller, A-form of PR is preferentially bound to specific DNA sequences both in the presence and in the absence of various salt concentrations. Thus, the differences in DNA binding of PR +/- salt do not correlate with the preferential binding of A or B isoform. The unequal behavior of PR subpopulations and/or isoforms for binding to specific DNA sequences offers added mechanisms for selective transcriptional regulation of genes in intact cells.
J Steroid Biochem Mol Biol 1998 Nov
PMID:Different populations of progesterone receptor-steroid complexes in binding to specific DNA sequences: effects of salts on kinetics and specificity. 987 84

The plant V-type H+-ATPase (V-ATPase) does not only serve basic housekeeping functions but is also involved in stress-induced NaCl sequestration during salinity stress. To address the question whether the same isoforms conferring housekeeping functions are equally involved in the response to high salinity, we have isolated cDNA clones for subunits A and c, as representing the peripheral V1 complex and the membrane-integral V0 complex, respectively, from the halotolerant sugar beet (Beta vulgaris L., diploid variety). RNA blot analysis with gene-specific probes revealed a coordinate expression of the cloned subunit A and c isoforms during plant development and in response to high salinity. Also, in rapidly dividing suspension-cultured cells with 10-fold increased transcript amounts as compared to young leaf tissue, the ratio of transcripts for both genes was similar to the ratio found for transcripts in leaves of different age. We have then isolated partial genomic clones (BVA/70 for Beta V-ATPase 70 kDa subunit; BVA/16-1 for Beta V-ATPase 16 kDa subunit), including the promoter regions. Transcription start mapping revealed long 5'-UTR leader sequences (230 and 172 bases, respectively) for both genes. Both promoters contain putative G-box motifs in similar distance to the TATA boxes. For a quantitative comparison of relative promoter strength, the BVA/70 and BVA/16-1 promoters linked to the luciferase reporter gene (LUC) were delivered to sugar beet suspension-cultured cells by particle bombardment. The BVA/16-1 promoter showed a 1.7-fold higher activity as compared with the BVA/70 promoter. Salt treatment induced an increase of BVA/70 (+70%) and BVA/16-1 (+57%) promoter activities, concomitant with increased transcript amounts. The following sequences have been deposited at the EMBL database X98767: Beta vulgaris V-ATPase subunit A, cDNA clone; X98851, B. vulgaris V-ATPase subunit c isoform 1, cDNA clone; Y11038, B. vulgaris V-ATPase subunit A, partial genomic clone; Y11037, B. vulgaris V-ATPase subunit c isoform 1, partial genomic clone.
Plant Mol Biol 1999 Feb
PMID:cDNA and genomic cloning of sugar beet V-type H+-ATPase subunit A and c isoforms: evidence for coordinate expression during plant development and coordinate induction in response to high salinity. 1009 75


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>