Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The previous report from our laboratory has recently identified a new trpE gene (termed trpE2) which exists independently in Azospirillum brasilense Yu62. In this study, amplification of trpE(G) (termed trpE1(G) here) confirmed that there are two copies of trpE gene, one trpE being fused into trpG while the other trpE existed independently. This is the first report to suggest that two copies of the trpE gene exist in this bacterium. Comparison of the nucleotide sequence demonstrated that putative leader peptide, terminator, and anti-terminator were found upstream of trpE1(G) while these sequence features did not exist in front of trpE2. The beta-galactosidase activity of an A. brasilense strain carrying a trpE2-lacZ fusion remained constant at different tryptophan concentrations, but the beta-galactosidase activity of the same strain carrying a trpE1(G)-lacZ fusion decreased as the tryptophan concentration increased. These data suggest that the expression of trpE1(G) is regulated at the transcriptional level by attenuation while trpE2 is constantly expressed. The anthranilate synthase assays with trpE1(G)- and trpE2- mutants demonstrated that TrpE1(G) fusion protein is feedback inhibited by tryptophan while TrpE2 protein is not. We also found that both trpE1(G) and trpE2 gene products were involved in IAA synthesis.
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PMID:Characterization of two trpE genes encoding anthranilate synthase alpha-subunit in Azospirillum brasilense. 1643 Aug 64

Several cell wall-bound glycosidases present in Avena sativa coleoptiles were assayed by following the hydrolysis of p-nitrophenyl-glycosides. Particular emphasis was placed on characterizing some parameters affecting the activity of beta-galactosidase. The pH optimum of this enzyme is 4.5 to 5.5; it is sensitive to copper ions and p-chloromercuribenzoate treatment and apparently has an exceptionally low turnover rate. Indoleacetic acid treatment enhanced in vivo beta-galactosidase activity of coleoptile segments by 36% over control after 60 minutes. This enhancement was prevented by abscisic acid and cycloheximide. High buffer strengths and low pH reduced the indoleacetic acid-enhanced increase in enzyme activity. These data lend support to the following proposed model of indoleacetic acid action. Indoleacetic acid enhances the release of hydrogen ions into the cell wall which promote the activities of cell wall glycosidases, some of which may participate in the cell extension process.
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PMID:Activation of Avena coleoptile cell wall glycosidases by hydrogen ions and auxin. 1665 80

To determine the utility of coupling runaway replication to the expression of cloned genes under the control of strong promoters, lacZ transcriptional fusions to the trp or tac promoter (Ptrp or Ptac) were constructed using plasmids in which the copy number is thermally regulated. Cells containing these plasmids were able to produce beta-galactosidase to levels between 3700 and 46,000 Miller units when induced only by a temperature upshift. The addition of the appropriate chemical inducer, either IPTG (isopropyl-beta-D-thiogalactopyranoside) or IAA (3-beta-indoleacrylic acid), did not significantly enhance the thermal induction. The Ptac-controlled and Ptrp-controlled lacZ induction differed slightly in that the Ptac-controlled thermal induction exhibited a lag of approximately 1.5 h as compared to both chemical and thermal induction, whereas in the case of Ptrp-controlled induction, an increase in beta-galactosidase expression above background occurred at approximately the same time regardless of the means of induction. The best vector, a Ptrp-controlled lacZ fusion carried on a runaway replication vector having a basal copy number of 10, was able to mediate the expression of beta-galactosidase to approximately 40,000 Miller units of beta-galactosidase comprising 25% of the total cell protein at 17 h postinduction under optimal conditions for protein yield. In these cells, lysis occurred as lacZ was maximally expressed. Under noninducing conditions, the plasmids were stable for at least 60 generations in the absence of antibiotic in batch culture.
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PMID:High-level expression of lacZ under control of the tac or trp promoter using runaway replication vectors in Escherichia coli. 1862 4

Pepper is an important vegetable worldwide and is a model plant for nonclimacteric fleshy fruit ripening. Drastic visual changes and internal biochemical alterations are involved in fruit coloration, flavor, texture, aroma, and palatability to animals during the pepper fruit ripening process. To explore the regulation of bell pepper fruit ripening by noncoding RNAs (ncRNAs), we examined their expression profiles; 43 microRNAs (miRNAs), 125 circular RNAs (circRNAs), 366 long noncoding RNAs (lncRNAs), and 3266 messenger RNAs (mRNAs) were differentially expressed (DE) in mature green and red ripe fruit. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the targets of the DE ncRNAs and DE mRNAs included several kinds of transcription factors (TFs) (ERF, bHLH, WRKY, MYB, NAC, bZIP, and ARF), enzymes involved in cell wall metabolism (beta-galactosidase, beta-glucosidase, beta-amylase, chitinase, pectate lyase (PL), pectinesterase (PE) and polygalacturonase (PG)), enzymes involved in fruit color accumulation (bifunctional 15-cis-phytoene synthase, 9-cis-epoxycarotenoid dioxygenase, beta-carotene hydroxylase and carotene epsilon-monooxygenase), enzymes associated with fruit flavor and aroma (glutamate-1-semialdehyde 2,1-aminomutase, anthocyanin 5-aromatic acyltransferase, and eugenol synthase 1) and enzymes involved in the production of ethylene (ET) (ACO1/ACO4) as well as other plant hormones such as abscisic acid (ABA), auxin (IAA), and gibberellic acid (GA). Based on accumulation profiles, a network of ncRNAs and mRNAs associated with bell pepper fruit ripening was developed that provides a foundation for further developing a more refined understanding of the molecular biology of fruit ripening.
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PMID:Network analysis of noncoding RNAs in pepper provides insights into fruit ripening control. 3121 63