Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activities of acid phosphatase, beta-glucuronidase, N-acethyl-beta-D-glucosaminidase and acid beta-galactosidase were investigated histochemically in rabbit corneas. Frozen sections after block fixation in cold 4% formaldehyde with 1% CaCl2 followed by washing in cold physiological saline as well as cold microtome sections of corneas quenched in petroleter chilled with acetone-dry ice mixture, transferred to nonprecooled slides or semipermeable membranes were used. Standard aqueous media were employed in the case of free-floating frozen sections of fixed corneas as well as of cold mictrotome sections (postfixed in cold 4% formaldehyde). Agar media were used in connection with the technic of semipermeable membranes. Gomori method (in the case of acid phosphatase), simultaneous azocoupling methods (substrates derivated of naphthol-AS-BI with hexazonium-p-rosanilin) in the case of acid phosphatase, beta-glucuronidase and N-acetyl-beta-D-glucosaminidase and the indigogenic method in the case of acid beta-galactosidase were applied. Enzyme activities in sections of fixed corneas were minimal in comparison with those in cold microtome sections of unfixed material revealed particularly with the technic of semipermeable membranes which is to be preferred. This technic is recommended in studies concerned with lysosomal enzymes in the cornea, particularly in keratocytes. All enzymes investigated were present in corneal epithelium, keratocytes and endothelium. Acid phosphatase displayed the highest activity followed by beta-glucuronidase and acetyl-beta-D-glucosaminidase. The activity of beta-galactosidase was the lowest. For the demonstration of activities in keratocytes sections parallel to the surface are very suitable. In these sections enzyme activities were demonstrated in small granules (apparently lysosomes) present in the central part of their cytoplasm as well as in projections. Diffuse staining was also seen, being the highest in the case of acid phosphatase.
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PMID:Distribution of acid phosphatase, beta-glucuronidase, n-acetyl-beta-d-glucosaminidase and beta-galactosidase in cornea of albino rabbit. 5 44

In alkali burned rabbit cornea the stainability of glycosaminoglycans in cold microtome setions was investigated. Staining by Alcian blue in 3% acetic acid, Alcian blue in various MgCl2 concentration and toluidine blue (pH 4.5) was employed. From the 1st to the 4th experimental day the intensity of reactions was decreased. This is most probably due to an increased hydration of the corneal stroma. On the 7th day hydration was markedly suppressed and reached nearly the normal level. In this time interval a decreased stainability of glycosaminoglycans was seen accompanied by a complete loss of staining in the marginal zone. On the 14th day the stainability in the traumatized area began to restore and in the marginal zone appeared. On the 32nd day the staining intensity of both areas was normalised, however when lower concentrations of MgCl2 were used; in the presence of higher concentrations of MgCl2 the decreased staining intensity persisted and points to a lower sulfatation of glycosaminoglycans. This was particularly remarkable in the area bordering the injured zone. This decrease runs parallel to the increased activities of acid glycosidases (especially of acid beta-galactosidase) which were reported previously.
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PMID:Alkali burns of the rabbit cornea. II. A histochemical study of glycosaminoglycans. 5 22

The catabolic phase of thyroid secretion --thyroglubulin (Tg) uptake and hydrolysis, release of hormones--has been investigated in vitro, by incubating thyroid slices with 0.1% labelled Tg, in cases of isolated adenomas. Twenty-two specimens were examined: 11 cold follicular adenomas, 5 hot nodules from euthyroid patients, 2 untreated toxic adenomas, and 4 pretreated toxic adenomas. The results were compared with those obtained in 11 specimens of normal tissue. Tg pinocytosis (the amount of Tg taken up by the slices per mg of tissue) was severely impaired in all the non-toxic nodules, cold or hot, i.e., whatever the in vivo activity of the thyroid iodide pump. In toxic adenomas, every step of the catabolic hormonogenesis was activated: high pinocytotic activity, increased Tg hydrolysis, and the discharge of hormonal products; in pretreated cases, the whole process was slowed down. Enzymic activity of the acid hydrolases, beta-galactosidase and cathepsin, was elevated in all the nodules so far investigated, particularly in the toxic adenomas.
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PMID:Secretory activity of isolated thyroid adenomas. 94 35

Escherichia coli promoters that are more active at low temperature (15 to 20 degrees C) than at 37 degrees C were identified by using the transposon Tn5-lac to generate promoter fusions expressing beta-galactosidase (beta-Gal). Tn5-lac insertions that resulted in low-temperature-regulated beta-Gal expression were isolated by selecting kanamycin-resistant mutants capable of growth on lactose minimal medium at 15 degrees C but which grew poorly at 37 degrees C on this medium. Seven independent mutants were selected for further studies. In one such strain, designated WQ11, a temperature shift from 37 degrees C to either 20 or 15 degrees C resulted in a 15- to 24-fold induction of beta-Gal expression. Extended growth at 20 or 15 degrees C resulted in 36- to 42-fold-higher beta-Gal expression over that of cells grown at 37 degrees C. Treatment of WQ11 with streptomycin, reported to induce a response similar to heat shock, failed to induce beta-Gal expression. In contrast, treatment with either chloramphenicol or tetracycline, which mimics a cold shock response, resulted in a fourfold induction of beta-Gal expression in strain WQ11. Hfr genetic mapping studies complemented by physical mapping indicated that in at least three mutants (WQ3, WQ6, and WQ11), Tn5-lac insertions mapped at unique sites where no known cold shock genes have been reported. The Tn5-lac insertions of these mutants mapped to 81, 12, and 34 min on the E. coli chromosome, respectively. The cold-inducible promoters from two of the mutants (WQ3 and WQ11) were cloned and sequenced, and their temperature regulation was examined. Comparison of the nucleotide sequences of these two promoters with the regulatory elements of other known cold shock genes identified the sequence CCAAT as a putative conserved motif.
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PMID:Identification and characterization of novel low-temperature-inducible promoters of Escherichia coli. 133 67

We have recently published that soluble cytosolic glucocorticoid receptors are converted to a particulate form when they are incubated at 37 degrees C in a tubulin-polymerizing buffer [Pratt, W. B., Sanchez, E. R., Bresnick, E. H., Meshinchi, S., Scherrer, L. C., Dalman, F. C., & Welsh, M. J. (1989) Cancer Res. (Suppl.) 49, 2222s-2229s]. In this work, we further define this phenomenon and demonstrate that the L-cell glucocorticoid receptors are binding to a protein particulate composed largely of cytoskeletal proteins. Incubation of L-cell cytosol with glutamate at 37 degrees C converts the glucorticoid receptor to a form that pellets when cytosol is centrifuged at 150000g. The particulate material formed in a temperature-dependent and glutamate-dependent manner contains a large amount of tubulin, actin, and vimentin, but it is not the product of a cold-labile, colchicine-sensitive polymerization process. Very few cytosolic proteins are present in this complex, but the glucocorticoid receptor is tightly bound to it. Binding of the receptor to the cytoskeletal complex occurs after receptor transformation and is at least partially energy-dependent. Examination of the behavior of beta-galactosidase receptor fusion proteins and the nti glucocorticoid receptor demonstrates that residues 445 to the COOH-terminus of the receptor (DNA-binding and hormone-binding domains) contain the features required for binding to the cytoskeletal complex. Although it is the transformed receptor that associates tightly with the complex, DNA-binding activity is not required for association with the cytoskeletal particulate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Energy-dependent conversion of transformed cytosolic glucocorticoid receptors from soluble to particulate-bound form. 135 99

A new class of cold shock-induced proteins that may be involved in an adaptive process required for cell viability at low temperatures or may function as antifreeze proteins in Escherichia coli and Saccharomyces cerevisiae has been identified. We purified a small Bacillus subtilis cold shock protein (CspB) and determined its amino-terminal sequence. By using mixed degenerate oligonucleotides, the corresponding gene (cspB) was cloned on two overlapping fragments of 5 and 6 kb. The gene encodes an acidic 67-amino-acid protein (pI 4.31) with a predicted molecular mass of 7,365 Da. Nucleotide and deduced amino acid sequence comparisons revealed 61% identity to the major cold shock protein of E. coli and 43% identity to a family of eukaryotic DNA binding proteins. Northern RNA blot and primer extension studies indicated the presence of one cspB transcript that was initiated 119 bp upstream of the initiation codon and was found to be induced severalfold when exponentially growing B. subtilis cell cultures were transferred from 37 degrees C to 10 degrees C. Consistent with this cold shock induction of cspB mRNA, a six- to eightfold induction of a cspB-directed beta-galactosidase synthesis was observed upon downshift in temperature. To investigate the function of CspB, we inactivated the cold shock protein by replacing the cspB gene in the B. subtilis chromosome with a cat-interrupted copy (cspB::cat) by marker replacement recombination. The viability of cells of this mutant strain, GW1, at freezing temperatures was strongly affected. However, the effect of having no CspB in GW1 could be slightly compensated for when cells were preincubated at 10 degrees C before freezing. These results indicate that CspB belongs to a new type of stress-inducible proteins that might be able to protect B. subtilis cells from damage caused by ice crystal formation during freezing.
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PMID:Characterization of cspB, a Bacillus subtilis inducible cold shock gene affecting cell viability at low temperatures. 140 Jan 85

Mammalian cell lysate containing beta-galactosidase (beta Gal) derived from the transient expression of the bacterial lacZ gene driven by the human beta-actin promoter loses activity progressively over time in storage at -20 degrees C in the presence of EDTA. The simultaneous presence of NaCl with EDTA exacerbates such an inactivation, although NaCl by itself does not. However, EGTA, a chelating agent that preferentially binds Ca2+ over Mg2+, does not inactivate beta Gal. Addition of equal or higher molar concentration of Mg2+ (as MgCl2) or Ca2+ (as CaCl2), both effectively chelated by EDTA, to an EDTA-containing lysate prevents this cold-related inactivation, but does not reactivate the enzyme. Therefore, the chelation of Mg2+ by EDTA at -20 degrees C inactivates beta Gal. Storage of cell lysate at -70 degrees C completely prevents the EDTA-induced inactivation of beta Gal. It is recommended that when beta Gal activity is used as the reporter for gene expression 1) EDTA should not be used to prepare cell lysate and 2) the cell lysate should be stored in a -70 degrees C freezer to preserve full activity.
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PMID:Magnesium chelation inactivates beta-galactosidase in -20 degrees C storage. 161 4

A method was developed for determining the specific activity of bacterial beta-galactosidase (EC 3.2.1.23) during growth of Streptococcus thermophilus and Lactobacillus bulgaricus in skim milk. Individual and mixed strain cultures of S. thermophilus (St 3642, St14485) and L. bulgaricus (Lb11842, Lb880) were examined for growth (OD at 600 nm and viable cell counts), acid production, and beta-galactosidase activity (expressed as a function of recoverable TCA-precipitable cellular protein). Cultures were inoculated into 10% skim milk (2% inoculum) and incubated at 40 degrees C for 12 h. Aliquots were removed at 2-h intervals and diluted with ice cold EDTA, pH 12. The EDTA chelates calcium and solubilizes milk protein, allowing separation of the bacteria by centrifugation. Cells were then washed twice with 20 mM phosphate buffer and disrupted by sonication. Cell debris and intact cells were removed by centrifugation and the cell-free extract evaluated for beta-galactosidase activity using o-nitrophenyl-beta-D-galactopyranoside as substrate. Specific activities ranged from 0 to 6 units/mg protein. This simple and reproducible method is applicable for enzyme assays and measurement of cellular components where contamination by milk proteins is a potential problem.
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PMID:A method for determining beta-galactosidase activity of yogurt cultures in skim milk. 249 15

We have constructed a derivative of the bacteriophage Mu (called MudIIZZ1), which contains the lacZ gene coding for beta-galactosidase (beta Gal) and markers suited for yeast transformation (2 mu circle replication origin and LEU2). This new transposon is an efficient tool for studying the expression of cloned yeast nucleotide sequences through beta Gal-protein fusions. It is also adapted for one-step disruption experiments so that a functional map of the same sequence can be drawn. We have used this MudIIZZ1 transposon to study a 5-kb DNA fragment which had been cloned by complementation of a cold-sensitive respiration-deficient phenotype. By testing the expression of the beta Gal fusions and the disruption phenotype, we have confirmed the presence of a gene required for mitochondrial functions, and revealed another two open reading frames in the same fragment; one of these also interferes with mitochondrial biogenesis. The method is fast and reliable, and has potential for more general purposes which are discussed.
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PMID:In vivo functional characterization of a yeast nucleotide sequence: construction of a mini-Mu derivative adapted to yeast. 283 69

1-Nitropyrene has been shown in bacterial assays to be the principal mutagenic agent in diesel emission particulates. It has also been shown to be mutagenic in human fibroblasts and carcinogenic in animals. To investigate the kinds of mutations induced by this carcinogen and compare them with those induced by a structurally related carcinogen, (+/-)-7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetra-hydrobenzo [a]pyrene (BPDE) (J.-L. Yang, V. M. Maher, and J. J. McCormick, Proc. Natl. Acad. Sci. USA 84:3787-3791, 1987), we treated a shuttle vector with tritiated 1-nitrosopyrene (1-NOP), a carcinogenic mutagenic intermediate metabolite of 1-nitropyrene which forms the same DNA adduct as the parent compound, and introduced the plasmids into a human embryonic kidney cell line, 293, for DNA replication to take place. The treated plasmid, pZ189, carrying a bacterial suppressor tRNA target gene, supF, was allowed 48 h to replicate in the human cells. Progeny plasmids were then rescued, purified, and introduced into bacteria carrying an amber mutation in the beta-galactosidase gene in order to detect those carrying mutations in the supF gene. The frequency of mutants increased in direct proportion to the number of DNA-1-NOP adducts formed per plasmid. At the highest level of adduct formation tested, the frequency of supF mutants was 26 times higher than the background frequency of 1.4 X 10(-4). DNA sequencing of 60 unequivocally independent mutant derived from 1-NOP-treated plasmids indicated that 80% contained a single base substitution, 5% had two base substitutions, 4% had small insertions or deletions (1 or 2 base pairs), and 11% showed a deletion or insertion of 4 or more base pairs. Sequence data from 25 supF mutants derived from untreated plasmids showed that 64% contained deletions of 4 or more base pairs. The majority (83%) of the base substitution in mutants from 1-NOP-treated plasmids were transversions, with 73% of these being G . C --> T . A. This is very similar to what we found previously in this system, using BPDE, but each carcinogen produced its own spectrum of mutations. Of the five hot spots for base substitution mutations produced in the supF gene with 1-NOP, two were the same as seen with BPDE-treated plasmids. However, the three other hot spots were cold spots for BPDE-treated plasmids. Conversely, four of the other five hot spots seen with BPDE-treated plasmids were cold spots for 1-NOP-treated plasmids. Comparison of the two carcinogens for the frequency of supF mutants induced per DNA adduct showed that 1-NOP-induced adducts were 3.8 times less than BPDE adducts. However, the 293 cell excised 1-NOP-induced adducts faster than BPDE adducts.
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PMID:Kinds and spectrum of mutations induced by 1-nitrosopyrene adducts during plasmid replication in human cells. 306 80


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