Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two forms of N-acetylglucosaminidase were purified to homogeneity by ion exchange (TSK DEAE-3SW, Aquapore CX-300) and gel filtration (TSK G4000 SW) HPLC of Candida albicans ATCC 10261 culture filtrates. Synthesis and secretion of N-acetylglucosaminidase were induced by incubating starved yeast cells at 37 degrees C in medium containing N-acetylglucosamine (GlcNAc). The form of the enzyme depended on the cell growth and starvation conditions before GlcNAc induction. N-Acetylglucosaminidase A (32% total carbohydrate, M(r) 85,000 subunit) was isolated from cells grown in glucose/salts/biotin medium, and N-acetylglucosaminidase B (56% carbohydrate, M(r) 132,000 subunit) was isolated from cells grown in yeast extract/peptone/dextrose. The estimated relative molecular masses of the native enzymes, based on Sephacryl S-300 gel filtration were: A form, 350,000; B form, 600,000; A and B forms after endoglycosidase H (endo H) treatment, 180,000. The purified enzymes migrated on SDS polyacrylamide gels as heterogeneous glycoproteins of M(r) centred at approximately 100,000 (A) and approximately 150,000 (B) but were reduced to a single 58,000 band after denaturation with SDS and cleavage of asparagine-linked sidechains by endo H. When the native glycoproteins were treated with endo H, both enzyme forms had three oligosaccharide sidechains of M(r) approximately 3000 that were endo H resistant. Therefore the difference in the size of N-acetylglucosaminidase A and B was due to variations in outer chain glycosylation of endo H-sensitive inner core structures. N-Acetylglucosaminidase was active and stable over a broad pH range with maximum activity against both p-nitrophenylGlcNAc (pNPGlcNAc) and pNPGalNAc at pH 4.0. The kinetic parameters kcat (s-1) and Km (mM) of N-acetylglucosaminidase A using the following substrates were, respectively: pNPGlcNAc, 740, 0.77; pNPGalNAc, 910, 1.26; N,N'-diacetylchitobiose 620, 0.20; and N,N',N"-triacetylchitotriose, 170, 0.044. The enzyme showed substrate inhibition with all substrates above 0.5 mM except for pNPGalNAc.
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PMID:Purification and characterization of two forms of N-acetylglucosaminidase from Candida albicans showing widely different outer chain glycosylation. 807 97

Gelatin SDS- polyacrylamide gel electrophoresis was used to compare proteinase banding patterns under reducing conditions from whole cell lysates of four axenic and four xenic pathogenic strains of Entamoeba histolytica. All strains shared major bands in the 34 and 66-68 kDa regions, whereas only the axenic strains produced major bands at 26, 28, 30 and 45 kDa. One axenic strain, NIH 200, when reassociated with mixed bacterial flora, reverted to an electrophoretic banding pattern characteristic of other xenic strains. These results suggest that the 26-30 kDa and 45 kDa proteinases of E. histolytica are induced by bacterial starvation while others are constitutively expressed. It is also proposed that the axenic bands of 45 and 34 kDa represent respectively, the reduced forms of the 56 and 40 kDa bands reported elsewhere under non-reducing conditions.
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PMID:Influence of bacteria on electrophoretic proteinase patterns of Entamoeba histolytica isolates. 822 72

1. We have established a murine hybridoma (F86) that secretes a monoclonal antibody (MoAb) specific for a 120 kDa nuclear protein (p120). p120 is expressed in all human cell lines investigated, whether of tumor or normal cell origin. 2. However, expression of p120 is significantly higher in neoplastic cells than in normal cells. The amount of p120 is relatively constant through the cell cycle and does not appear to be modulated by 72 hr serum starvation. 3. These results suggest that p120 plays some role in nuclear events associated with neoplastic phenotypes rather than in cell proliferation. 4. In situ immunofluorescence analyses indicate that p120 is located exclusively in nuclei of interphase cells. It is not present in nucleoli. 5. During mitosis, p120 is distributed in the cytoplasm and is not associated with condensed chromosomes which, together with RNAse experiments, suggests that it may be associated with hnRNA or hnRNP particles. 6. Western blot analyses indicate that p120 consists of two molecular weight forms which differ by 2-3 kDa in reduced SDS-PAGE, and several isoelectric variants in the acidic range. 7. Fractionation studies indicate that p120 has accessible free sulfhydryl group(s) and can bind ssDNA and heparin. 8. A partial cDNA clone, encoding the carboxyl terminus of p120, was isolated from a lambda gt11 library which had been prepared from human hepatoma cells (KYN-1). 9. Sequence analysis of the open reading frame revealed two possible nuclear localization sequences and several clusters of acidic amino acid residues, including a continuous run of 11 glutamic acid residues. 10. Northern blot analyses of human hepatoma RNA revealed hybridization to three transcripts which are about 4.1, 3.6, and 0.6 kb in size. 11. Dot blot analyses show that these transcripts are about 10-fold more abundant in KYN-1 hepatoma cells than in normal liver cells.
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PMID:A tumor-associated 120 kDa nuclear protein: characterization using a monoclonal antibody and a partial cDNA clone. 844 14

The utilization of S-adenosyl-L-[methyl-3H]methionine ([3H-methyl]AdoMet) by Crithidia luciliae was assessed under nutrient-replete and purine-starvation conditions. Uptake experiments with intact cells demonstrated that the radiolabel from this molecule was accumulated by purine-starved organisms at a rate approximately 10-fold greater than that observed in those cultivated in nutrient-replete medium. Purine-starved cells also incorporated the radiolabel into trichloroacetic acid insoluble material at an approximately 10-fold faster rate than nutrient-replete cells. No differences, however, were observed in the intracellular levels of AdoMet and its metabolites between organisms cultivated under the two conditions. Results of comparative labeling studies with [3H-methyl]AdoMet, S-adenosyl-L-[carboxyl-14C]methionine, L-[methyl-3H]methionine and L-[35S]methionine in the presence and absence of cycloheximide demonstrated that the incorporation of label from [3H-methyl]AdoMet was due to transmethylation and was independent of protein synthesis. Further, approximately 15 methylated protein bands were identified by SDS-PAGE analysis. Lysates from both purine-starved and nutrient-replete organisms demonstrated similar levels of activity of three protein methyltransferases (PMI, II, III). The differences observed in [3H-methyl]AdoMet utilization between purine-starved and nutrient-replete C. luciliae may reflect the enhanced purine transport capacity which results from purine starvation.
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PMID:Crithidia luciliae: effect of purine starvation on S-adenosyl-L-methionine uptake and protein methylation. 854 93

A secreted phosphodiesterase/alkaline phosphatase, APaseD, was purified from a culture of Bacillus subtilis JH646MS. Its phosphodiesterase activity was reminiscent of an APase isolated and characterized previously. Immunoassay and N-terminal sequencing showed the two proteins to be identical. Using the first 20 amino acids of the mature protein, a BLAST search of GenBank was used to find an homologous sequence. An exact match was found but in a putative non-coding region. It was hypothesized that there was a base pair deletion in the phoD gene. A DNA fragment internal to the coding region was generated by PCR using template DNA from a strain which produced APaseD. The PCR fragment was cloned and used to interrupt the gene. Western blot analysis of the parent and the mutated strains showed that APaseD was missing in the mutant. Resequencing of the gene revealed a larger ORF encoding a protein similar in size to the 49 kDa APaseD estimated by SDS-PAGE. The promoter was then cloned, sequenced and used in phoD-lacZ promoter fusions which showed that the gene was phosphate-starvation-induced and dependent on PhoP and PhoR for expression.
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PMID:A Bacillus subtilis secreted phosphodiesterase/alkaline phosphatase is the product of a Pho regulon gene, phoD. 876 Sep 16

Previous work has shown that clinical Escherichia coli strains, starved in seawater, are able to present residual growth, with subsequent alterations to their enzymatic activities and metabolism. Gelatinolytic activity of starved cells is of importance because it appears and increases gradually with time. In this work, several forms of gelatinolytic activity were detected by SDS-polyacrylamide gel electrophoresis, differing in molecular masses and appearance, before and after starvation of E. coli cells. The enzymic forms are classified into 4 categories according to the effect of certain inhibitors on the appearance of gelatinolytic activity: a. those whose appearance is inhibited by the chelating factors EDTA, 1,10-phenanthroline and whose presence is also inhibited by N-ethylmaleimide (metalloproteinases with thiol group active); b. those affected by the presence of chelators, N-ethylmaleimide and Ca2+ (Ca2(+)-dependent metalloproteinases with thiol group active); c. those inhibited by chelators and activated in the presence of Ca2+ (Ca2(+)-dependent metalloproteinases) and d. those whose appearance is independent of the presence of inhibitors used. The forms of gelatinolytic activity of the fourth category coincide with enzyme forms that can also use casein as substrate in electrophoresis. These data suggest that there are considerable differences in the gelatinolytic pattern of clinical strains of E.coli cells before and after starvation in seawater.
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PMID:Study of the gelatinolytic activities Escherichia coli cells before and after starvation in seawater by substrate gel electrophoresis. 881 23

Many previous studies have demonstrated that antisense oligodeoxynucleotides (ODNs) bind to surface proteins in a manner compatible with receptor-mediated endocytosis and, unless specifically modified, are internalized into endosomes with little access to the cytoplasmic structures or to the nucleus. Reports vary as to the specific proteins involved in the mechanism, and this study examines the conditions of binding, some proteins that might contribute to the process, and whether changes in binding patterns occur during differentiation. Native gel electrophoresis was used to optimize the surface binding of a phosphorothioate end-capped 16-mer to T15 mouse fibroblast cells, and comparisons are made with some human epithelial tumor cell lines. Binding to individual proteins was visualized using SDS-PAGE and autoradiography. Binding at 4 degrees C was almost exclusively to a 46 kDa protein and decreased in the presence of an excess of unlabeled ODN and heparin but not ATP. Increasing the temperature of ODN binding from 4 degrees C to 37 degrees C for 10 minutes changed the binding pattern observed. ODN binding to the total cytoplasmic and membrane proteins immobilized on a membrane showed a greater number of binding proteins, the most prominent being one of 30 kDa. Examination of the effects of serum on binding were made using the human lung carcinoma cell line COR-L23, which can be grown in serum-free conditions. Serum starvation led to an increased total binding seen on native gels coinciding with increased binding to a 46 kDa protein. Demonstration that changes in binding proteins occur when cells differentiate was made using the premacrophage cell line THP-1. Differentiation of these cells increased the total ODN binding and appeared to initiate the synthesis of some new binding proteins, although binding to a 46 kDa protein was reduced.
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PMID:Interaction of oligodeoxynucleotides with mammalian cells. 891 3

An endopeptidase (designated RSIP, for root-starvation-induced protease) was purified to homogeneity from glucose-starved maize roots. The molecular mass of the enzyme was 59 kDa by SDS/PAGE under reducing conditions and 62 kDa by gel filtration on a Sephacryl S-200 column. The isoelectric point of RSIP was 4.55. The purified enzyme was stable, with no auto-proteolytic activity. The enzyme activity was strongly inhibited by proteinaceous trypsin inhibitors, di-isopropylfluorophosphate, 3,4-dichloroisocoumarin and PMSF, suggesting that the enzyme is a serine protease. The maximum proteolytic activity against different protein substrates occurred at pH 6.5. With the exception of succinyl-Leu-Leu-Val-Tyr-4-methylcoumarin, no hydrolysis was detected with synthetic tryptic, chymotryptic or peptidylglutamate substrates. The determination of the cleavage sites in the oxidized B-Chain of insulin showed specificity for hydrophobic residues at the P2 and P3 positions, indicating that RSIP is distinct from other previously characterized maize endopeptidases. Both subcellular fractionation and immuno-detection in situ indicated that RSIP is localized in the vacuole of the root cells. RSIP is the first vacuolar serine endopeptidase to be identified. Glucose starvation induced RSIP: after 4 days of starvation, RSIP was estimated to constitute 80% of total endopeptidase activity in the root tip. These results suggest that RSIP is implicated in vacuolar autophagic processes triggered by carbon limitation.
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PMID:Purification and biochemical characterization of a vacuolar serine endopeptidase induced by glucose starvation in maize roots. 894 99

A phosphate-starvation-inducible outer-membrane protein of Pseudomonas fluorescens Ag1, expressed at phosphate concentrations below 0.08-0.13 mM, was purified and characterized. The purification method involved separation of outer-membrane proteins by SDS-PAGE and extraction of the protein from nitrocellulose or PVDF membranes after electrotransfer of proteins to the membranes. The N-terminal amino acid sequence of the purified protein, called Psi1, did not show homology to any known proteins, and in contrast to the phosphate-specific porin OprP of P. aeruginosa its mobility in SDS-PAGE was not affected by solubilization temperature. An antiserum against Psi1 recognized a protein of M, 55,000 in four other P. fluorescens strains among 24 tested strains representing Pseudomonas rRNA homology group I, showing antigenic heterogeneity within this group. A method for immunofluorescence microscopy involving cell permeabilization was adapted to visualize cell-specific expression of Psi1 in P. fluorescens exposed to limiting amounts of phosphate. This approach should be useful for further exploration of Psi1 as a marker to study the availability of phosphate to P. fluorescens in natural environments.
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PMID:A phosphate-starvation-inducible outer-membrane protein of Pseudomonas fluorescens Ag1 as an immunological phosphate-starvation marker. 908 84

A technique for detection of the activity of hydroxylamine oxidoreductase (HAO) involving denaturing SDS-polyacrylamide gels was developed. The activity of HAO of Nitrosomonas europaea was assayed using this technique, which revealed a single active band of 140 kDa. The HAO activity of other ammonia-oxidizers was also resistant to SDS, the molecular weights being identical to that of N. europaea. N. europaea cells starved of ammonia for up to 72 h retained a considerable amount of HAO, as detected on Western blot analysis, and a significant level of its activity, as found on assaying at the end of the starvation period. Only after 4 h incubation of starved N. europaea cells with 2.0 mM ammonia was some increase in the HAO level observed. The results indicate that HAO remains highly stable during ammonia starvation of N. europaea.
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PMID:Effect of ammonia starvation on hydroxylamine oxidoreductase activity of Nitrosomonas europaea. 919 39


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