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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Big Blue (BB) and generic B6C3F1 mice were given one to three i.p. injections of 50 mg/kg benzo[a]pyrene (B[a]P) in DMSO every other day to achieve cumulative doses of 50 to 150 mg/kg. Three weeks after treatment, the mutation frequency at the endogenous hprt gene and lacI transgene was measured in splenic T cells. Generic mice given 50, 100, and 150 mg/kg B[a]P displayed induced hprt frequencies (observed hprt frequency minus control frequency) of 5.5 +/- 1.0, 11 +/- 2.0, and 19 +/- 2.6 x 10(-6), respectively (average +/- SEM). In contrast, BB mice given 50 and 150 mg/kg B[a]P displayed induced hprt frequencies of 0.9 +/- 0.6 and 9.1 +/- 1.5 x 10(-6). 32P postlabelling revealed that the lower hprt response in BB mice correlated with lower amounts of BP-DNA adducts in spleen, liver, and lung 24 hours after B[a]P exposure. Western blot analysis of liver samples from B[a]P-treated mice suggests that the reduced adduct load in turn may be due to lower P450 1A1 levels in BB mice. The frequency of induced, nonsectored blue plaques (observed blue plaque frequency minus control frequency) in BB mice receiving 50 and 150 mg/kg B[a]P was 41 +/- 9 and 134 +/- 10 x 10(-6) (15- to 40-fold higher than the induced hprt frequency in the same treated animals). Sectored plaques were observed in both control and B[a]P groups but their frequency showed no relationship to dose (sectored frequency in all groups was approximately 20 x 10(-6)). To test whether persistent DNA adducts in the packaged lambda vector were contributing to the observed blue plaque frequency, purified lambda-LIZ DNA was treated in vitro with B[a]P diol epoxide (BPDE), packaged, and plated on E. coli lawn cells. Treatment with BPDE did not produce significant increases in homogeneous blue plaques, suggesting that the majority of mutants obtained from B[a]P-treated BB mice occurred in vivo. These results indicate that B[a]P exposure produces many more mutations at the lacI transgene than at the endogenous hprt locus.
Environ Mol Mutagen 1996
PMID:Mutagenic response of the endogenous hprt gene and lacI transgene in benzo[a]pyrene-treated Big Blue B6C3F1 mice. 899 Oct 66

This study used the colorimetric MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide)] assay to assess cell viability in isolated quiescent adult guinea-pig ventricular myocytes exposed to different insults or cardioprotective conditions, including adenosine and hyperkalemic-cardioplegia. Optical density (OD), reflecting intracellular reduction of MTT into formazan pigment formation, was a function of the number of viable cells (coefficient of linear correlation approximately 0.99), with MTT reduction preferentially carried out by rod-shaped cardiomyocytes (absorbance at 1.009 +/- 0.013 and 0.006 +/- 0.001 OD units for populations containing 50 and 0% of rod-shaped cells). Following prolonged mechanical (pressure of 1 lb/min for 40 min), chemical (10% DMSO or ethanol) or hypoxic injury (N2-saturated solution), the MTT reductase activity reflected reduction in the number of viable cells by 87%, >50%, and 77%, respectively. In cardiomyocytes exposed to a 40 min hypoxia (with CO2), the MTT reductase activity was 0.056 +/- 0.009 in the absence, and 0.074 +/- 0.008 OD units in the presence of adenosine (1 mM), i.e. adenosine reduced the number of non-viable cells. Also, the MTT assay revealed that the effect of potassium-containing solutions (16 and 32 mM K+) on cellular viability may depend on the extent of insult imposed on cardiomyocytes; i.e. a approximately 24% and 49% increase under mild hypoxia (0.03% CO2), or an 18% decrease in cell viability under severe hypoxia (N2) in pre-injured cells. Thus, the MTT assay used to assess viability of isolated adult cardiomyocytes revealed a direct cytoprotective effect of adenosine and hyperkalemic-cardioplegia by promoting cell survival under certain conditions in vitro.
J Mol Cell Cardiol 1997 Apr
PMID:Use of the MTT assay in adult ventricular cardiomyocytes to assess viability: effects of adenosine and potassium on cellular survival. 916 Aug 77

The amino acid and carbohydrate analysis of scyllin, a low molecular weight lectin purified from Scylla serrata (edible crab) haemolymph reveal that scyllin is rich in acidic and neutral amino acids and contains high amount of mannose. UV absorption of scyllin is perturbed by DMSO at 272 nm showing the presence of tryptophan molecule in scyllin exposed and accessible to the solvent. The oxidation of tryptophan molecule by N-bromosuccinimide results in loss of haemagglutinating activity of lectin. The study of thermodynamic parameters of scyllin-glycoproteins interaction suggests that ceruloplasmin is the most potent inhibitors of scyllin of all the glycoproteins studied.
Biochem Mol Biol Int 1997 Jun
PMID:Further biochemical and biophysical characterisation of scyllin, Scylla serrata hemolymph lectin. 919 99

Myxococcus xanthus is a Gram-negative, soil-dwelling bacterium with a complex life cycle which includes fruiting body formation and sporulation in response to starvation. This developmental process is slow, requiring a minimum of 24-48 h, and requires cells to be at high cell density on a solid surface. It is known that, in the absence of starvation, vegetatively growing cell suspensions can form 'glycerol spores' when exposed to high levels of glycerol, usually 0.5 M. The cells differentiate from rods to resistant spheres rapidly (2-4 h) and synchronously. We have found that the chromosomally encoded beta-lactamase of M. xanthus can be induced by numerous beta-lactam antibiotics as well as by non-specific inducers including glycine and many D-amino acids. In addition, D-cycloserine, phosphomycin, and hen egg-white lysozyme also induce beta-lactamase in this bacterium. Unexpectedly, agents which induce beta-lactamase can induce 'glycerol spores'; all of the agents tested which induce glycerol spores (glycerol, DMSO, ethylene glycol) also induce beta-lactamase. During the induction of sporulation, beta-lactamase activity increases, reaching a peak during the morphological transition from rod-shaped cells to spherical spores. These spores are viable and resistant to many treatments which disrupt vegetatively growing rods but are not as resistant as fruiting body spores. The concomitant induction of beta-lactamase and starvation-independent sporulation suggests that these processes share a common signal-transduction pathway. These results also suggest that starvation-independent sporulation may be an adaptation of cells in order to resist agents that damage peptidoglycan structure and therefore threaten cell survival.
Mol Microbiol 1997 May
PMID:Starvation-independent sporulation in Myxococcus xanthus involves the pathway for beta-lactamase induction and provides a mechanism for competitive cell survival. 919 10

DNA differential display analysis (DD-PCR) was utilized to identify genes that are expressed in airway epithelium and are relevant to airway inflammation; cytokine-mediated induction of gene expression and inhibition of that induction by glucocorticoids were the criteria for selection. The IB3-1 cell line was cultured in the presence of tumor necrosis factor-alpha (TNF-alpha), dexamethasone, or dimethyl sulfoxide (DMSO) as a control, and analyzed via DD-PCR and Northern blot analyses. With this approach, two TNF-alpha-inducible and dexamethasone (DEX)-sensitive expressed sequence tags (EST8 and EST19) were identified. In IB3-1 cells, TNF-alpha increased messenger RNA (mRNA) expression of EST8 (34%, P < or = 0.005) and EST19 (41%, P < or = 0.01), whereas dexamethasone reduced this expression to resting levels. This pattern of mRNA expression was also observed in normal human bronchial epithelial cells (EST8: 21%, P < or = 0.009; EST19: 11%, P < or = 0.02) and in the basophil leukemia cell line KU812 (EST8: 34%, P < or = 0.01). Through basic local alignment search tool (BLAST) analysis, it was determined that these ESTs exhibited significant homology with the monomeric G protein rhoC (EST8: 100% homology, P = 1.6 x 10(-100)) and the UFO tyrosine kinase receptor (EST19: 86% homology, 5.3 x 10(-28).
Am J Respir Cell Mol Biol 1997 Jul
PMID:Identification of novel inducible genes in airway epithelium. 922 16

Activation of oocytes is caused by osmotic pressure change in some species. However, cryopreservation of oocytes occurs in the presence of osmotic pressure change induced by cryoprotectants. We investigated the effect of 5-(N,N,-dimethyl)-amiloride (NNDMA), a selective inhibitor of Na+/H+ exchange, on the cryopreservation and osmotic activation of mouse oocytes. The percentage (23.2%) of degenerate oocytes after cryopreservation in the presence of NNDMA was found to be lower than that (39.5%) of untreated oocytes. After thawing, the percentage (23.6%) of oocytes which could be fertilized following cryopreservation in the presence of NNDMA was significantly higher than that of untreated (18.0%) oocytes. These results suggest that amiloride increased the survival rate after thawing following cryopreservation. To investigate the effect of NNDMA on oocyte activation caused by the cryoprotectant, dimethyl sulphoxide (DMSO) was used to induce osmotic pressure change. NNDMA was found to inhibit cortical granule exocytosis, the second polar body emission and pronuclear formation which occurs upon activation due to osmotic pressure change. It also inhibited the increase in phosphorylation of many proteins including 33 and 45 kDa proteins, which occurs, during fertilization and chemical oocyte activation. In contrast, protein phosphorylation was not inhibited by W7, a calmodulin inhibitor. The actions of these inhibitors suggest that oocyte activation induced by osmotic pressure change involves a pathway mediated by Na+/H+ exchange which may be distinct from the Ca-calmodulin pathway. Amiloride may be a useful drug for increasing the rate of survival of cryopreserved oocytes.
Mol Hum Reprod 1996 Nov
PMID:Egg activation induced by osmotic pressure change and the effects of amiloride on the cryopreservation of mouse oocytes. 923 32

The distribution of alpha- and gamma-tubulin in human and mouse oocytes has been investigated immunocytochemically. Comparisons have been made between freshly recovered and aged oocytes (both human and mouse), and also between human oocytes before and after exposure to cryoprotectant. Control fresh human oocytes had compact anastral spindles oriented orthogonal to the oolemma, with the pole adjacent to the oolemma being smaller than that directed towards the centre of the oocyte. Each pole was associated with a ring of particulate gamma-tubulin staining that extended a short distance into the body of the spindle. No alpha- and gamma-tubulin staining was found elsewhere in the ooplasm. Human oocytes which had failed to fertilize after an 18 h incubation with spermatozoa and had spent a further 6-8 h in culture showed an increased incidence of spindle abnormalities and of the proliferation of ooplasmic microtubules, which became more pronounced with age post-ovulation. The gamma-tubulin staining pattern of these aged human oocytes revealed greater staining over the whole of the spindle than in fresh oocytes. Examination of mouse oocytes aged in vitro or in vivo showed similar evidence of microtubule proliferation and disorganization, and the gamma-tubulin staining pattern was a sensitive indicator of ageing. The spindles of most fresh human oocytes exposed to 1.5 M dimethyl sulphoxide (DMSO) at 4 degrees C differed from controls in being slightly reduced in size or in having more pointed spindle poles with smaller diameters, both indications that some dismantling of the microtubules had occurred. The distribution of gamma-tubulin in these oocytes extended over more of the spindle. Restoration of DMSO-exposed oocytes to control medium at 37 degrees C for an extended period restored spindle structure to a state closely resembling that in controls. However, recovery of an exclusively polar gamma-tubulin staining did not occur. In both controls and DMSO-exposed human oocytes, chromosomes were arranged on the metaphase equatorial plate. In contrast, exposure of oocytes to 4 degrees C in the absence of DMSO caused dismantling of the spindle. It is concluded that (i) changes in microtubule organization with ageing of oocytes makes them unsuitable for use therapeutically after re-insemination or intracytoplasmic sperm injection, (ii) conditions of cryoprotectant addition previously found optimal for the stabilization of the spindle in the mouse oocyte also appear to be effective in stabilizing the spindle of the human oocyte, and (iii) the distribution of gamma-tubulin in relation to the spindle of the human oocyte appears to be sensitive to age and conditions.
Mol Hum Reprod 1996 Jun
PMID:The distribution of alpha- and gamma-tubulin in fresh and aged human and mouse oocytes exposed to cryoprotectant. 923 15

Polychaetes, because of their bioturbation capacity, play an important role in the distribution of anthropogenic contaminants (including polycyclic aromatic hydrocarbons [PAHs]) throughout the sediments. In this work the use of Nereis virens (Annelida: Polychaeta) as a bioindicator to assess the genotoxic risk of PAH exposure for the environment was evaluated. For this purpose the alkaline single cell gel electrophoresis [comet] assay was applied on the coelomocytes of in vivo exposed Nereis virens. Benzo[a]pyrene (B[a]P) was chosen because it is classified by the IARC (International Agency for Research on Cancer) as "probably carcinogenic to humans" and because its mechanisms of action are well-known. Nereis virens was exposed to B[a]P in concentrations of 0.3, 0.6, 10, 20, 35 and 45 mg/ml by an intracoelomic injection of B[a]P (20 microliters) dissolved in dimethyl sulphoxide (DMSO). A solvent control with DMSO, a positive control with ethyl methane sulphonate (EMS) (12.1 mg/ml) and a negative control were included in each experiment. For each treatment four animals were analysed. After 1 hr treatment coelomocytes were harvested by puncturing the coelomic cavity with a sharpened Pasteur pipette, mixed with 0.5% low melting point agarose and sandwiched between two other gel layers. Ethidium bromide stained nuclei were analysed for tail length and tail moment. 12.1 mg/ml EMS, pure DMSO (98.9%) and B[a]P in all tested concentrations induced a statistically significant increase of DNA single strand breaks in the comet assay. The effect of B[a]P, however, was only at the highest concentration (45 mg/ml) significantly stronger than the effect of DMSO alone. Although a relatively large heterogeneity in the results could be observed, these experiments clearly showed that Nereis virens is not suited as a sentinel species for the assessment of the genotoxic risk of PAH exposure because this species seems to be very resistant to benzo[a]pyrene.
Environ Mol Mutagen 1997
PMID:Nereis virens (Annelida: Polychaeta) is not an adequate sentinel species to assess the genotoxic risk (comet assay) of PAH exposure to the environment. 925 33

In sperm cells, the majority of coenzyme Q10 (CoQ10) an energy promoting agent and antioxidant, is concentrated in the mitochondria of the midpiece, so that the energy for movement and all other energy-dependent processes in the sperm cell also depend on the availability of CoQ10. The reduced form of CoQ10-ubiquinol also acts as an antioxidant, preventing lipid peroxidation in sperm membranes. The objective of the study was to evaluate the effect of CoQ10 on sperm motility in vitro, after incubation with 38 samples of asthenospermic and normal motility sperm, and to evaluate the effect of CoQ10 administration in vivo in 17 patients with low fertilization rates after in vitro fertilization with intracytoplasmic sperm injection (ICSI) for male factor infertility. All 38 sperm samples from patients registered in our infertility clinic had normal concentrations and morphology. Of these, 16 patients had normal motility (mean 47.5%) and 22 patients were asthenospermic (mean motility 19.1%). Sperm samples were divided into four equal parts and incubated for 24 h in: HAM's medium alone, in HAM's medium with 1% DMSO and HAM's with 5 microM or 50 microM CoQ10. While no significant change in motility after incubation was observed in the samples with initial normal motility, a significant increase in motility was observed in the 50 microM CoQ10 subgroup of sperm from asthenospermic men, with a motility rate of 35.7 +/- 19.5%, as compared to 19.1 +/- 9.3% in the controls (P < 0.05). The 17 patients with low fertilization rates after ICSI were treated with oral CoQ10, 60 mg/day, for a mean of 103 days before the next ICSI treatment. No significant change was noted in most sperm parameters, but a significant improvement was noted in fertilization rates, from a mean of 10.3 +/- 10.5% in their previous cycles, to 26.3 +/- 22.8% after CoQ10 (P < 0.05). In conclusion, the administration of CoQ10 may result in improvement in sperm functions in selective patients. Further investigation into the mechanisms related to these effects is needed.
Mol Aspects Med 1997
PMID:The effect of coenzyme Q10 on sperm motility and function. 926 24

The use of primers synthesized to eight class II restriction endonuclease target sequences, from Haemophilus parainfluenzae, Escherichia coli, Staphylococcus aureus, Salmonella infantis, Rhodobacter sphaeroides, Klebsiella pneumoniae, Bacillus amyloliquefaciens and Proteus vulgaris for single and multiplex PCR identification of the organisms is discussed. Results indicate that the method is sensitive and specific enough to detect single cells and attogram amounts of target DNA. It has also been demonstrated that the primers can be used in whole cell PCR for identification and whole cell PCR product recovery could be enhanced by the addition of gelatin or DMSO to PCR reaction mixtures. Other results have indicated that the method can be used for the definite identification of specific individuals present in mixed cultures or suspensions of organisms. The applicability of the method for detection of a specific strain within a group of closely related organisms has also been investigated and for that sequence/organism the results suggest that the proposed method is indeed very specific and discriminative. It is suggested that as more information becomes available regarding such sequences and their distribution, this approach could form the basis of a widescale, rapid, simple and cheap identification and/or typing system for bacteria.
Mol Cell Probes 1997 Aug
PMID:Rapid, sensitive, microbial detection by gene amplification using restriction endonuclease target sequences. 928 17


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