scholarly journals Effect of Glucose on Endo-xylanase and β-xylosidase Production by Fungi Isolated in Indonesia

2022 ◽  
Author(s):  
Ririn Krisnawati ◽  
Sardjono ◽  
Jaka Widada ◽  
Dian Anggraini Suroto ◽  
Muhammad Nur Cahyanto
Keyword(s):  
Liquid Medium ◽  
Growth Medium ◽  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
The Other ◽  
Trichoderma Asperellum ◽  
Aspergillus Aculeatus ◽  
Xylanase Production ◽  
Degrading Enzymes ◽  
Effect Of Glucose

Xylanases are widely produced by fungi, and the production of polysaccharide-degrading enzymes, in general, are usually subjected to carbon catabolite repression. In this work, the ability of several Indonesian indigenous fungi to produce endo-xylanase and β-xylosidase and their responses to glucose as a repressor were determined. Ten fungi were grown in a liquid medium supplemented with glucose as the repressor (0, 1%, 3%, and 5%), and the endo-xylanase and β-xylosidase productions were assayed. Aspergillus aculeatus FIG1 and A. oryzae KKB4 produced 3.85 and 0.70 U/mL of endo-xylanase, respectively, compared with other strains (0.22 U/mL or less). Trichoderma asperellum PK1J2, T. virens MLT2J2, A. aculeatus FIG1, T. asperellum MLT5J1, A. oryzae KKB4, and T. asperellum MLT3J2 produced 0.021–0.065 U/mL of β-xylosidase, whereas the other strains produced 0.013 U/mL or less of β-xylosidase. Adding 1% glucose to the growth medium can partially repress endo-xylanase production in A. aculeatus FIG1, T. asperellum PK1J2, and T. virens MLT4J1 and completely repress other strains. By adding 1% glucose, strains FIG1, PK1J2, and MLT4J1 suffered almost complete repression of β-xylosidase production, although such strains exhibited partial repression of endo-xylanase production. β-Xylosidase produced by the other strains showed complete repression by adding 1% glucose, except for A. aculeatus FIG1, A. tamarii FNCC 6151, and T. asperellum MLT1J1, which showed partial repression. Therefore, adding 3% glucose to the growth medium can result in complete repression of endo-xylanase and β-xylosidase productions in all strains examined.

scholarly journals Regulation ofAspergillus nidulansCreA-Mediated Catabolite Repression by the F-Box Proteins Fbx23 and Fbx47

mBio ◽  
2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Leandro José de Assis ◽  
Mevlut Ulas ◽  
Laure Nicolas Annick Ries ◽  
Nadia Ali Mohamed El Ramli ◽  
Ozlem Sarikaya-Bayram ◽  
...  
Keyword(s):  
Carbon Source ◽  
Aspergillus Nidulans ◽  
Ubiquitin Ligase ◽  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
26S Proteasome ◽  
Xylanase Production ◽  
Content Type ◽  
Regulatory Pathways ◽  
Ubiquitin Ligase Complex

ABSTRACTThe attachment of one or more ubiquitin molecules by SCF (Skp–Cullin–F-box) complexes to protein substrates targets them for subsequent degradation by the 26S proteasome, allowing the control of numerous cellular processes. Glucose-mediated signaling and subsequent carbon catabolite repression (CCR) are processes relying on the functional regulation of target proteins, ultimately controlling the utilization of this carbon source. In the filamentous fungusAspergillus nidulans, CCR is mediated by the transcription factor CreA, which modulates the expression of genes encoding biotechnologically relevant enzymes. Although CreA-mediated repression of target genes has been extensively studied, less is known about the regulatory pathways governing CCR and this work aimed at further unravelling these events. The Fbx23 F-box protein was identified as being involved in CCR and the Δfbx23mutant presented impaired xylanase production under repressing (glucose) and derepressing (xylan) conditions. Mass spectrometry showed that Fbx23 is part of an SCF ubiquitin ligase complex that is bridged via the GskA protein kinase to the CreA-SsnF-RcoA repressor complex, resulting in the degradation of the latter under derepressing conditions. Upon the addition of glucose, CreA dissociates from the ubiquitin ligase complex and is transported into the nucleus. Furthermore, casein kinase is important for CreA function during glucose signaling, although the exact role of phosphorylation in CCR remains to be determined. In summary, this study unraveled novel mechanistic details underlying CreA-mediated CCR and provided a solid basis for studying additional factors involved in carbon source utilization which could prove useful for biotechnological applications.IMPORTANCEThe production of biofuels from plant biomass has gained interest in recent years as an environmentally friendly alternative to production from petroleum-based energy sources. Filamentous fungi, which naturally thrive on decaying plant matter, are of particular interest for this process due to their ability to secrete enzymes required for the deconstruction of lignocellulosic material. A major drawback in fungal hydrolytic enzyme production is the repression of the corresponding genes in the presence of glucose, a process known as carbon catabolite repression (CCR). This report provides previously unknown mechanistic insights into CCR through elucidating part of the protein-protein interaction regulatory system that governs the CreA transcriptional regulator in the reference organismAspergillus nidulansin the presence of glucose and the biotechnologically relevant plant polysaccharide xylan.

Analysis of mutations in the creA gene involved in carbon catabolite repression in Aspergillus nidulans

1996 ◽  
Vol 42 (9) ◽  
pp. 950-959 ◽  
Author(s):  
Robert A. Shroff ◽  
Robin A. Lockington ◽  
Joan M. Kelly
Keyword(s):  
Zinc Finger ◽  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
Zinc Finger Protein ◽  
The Other ◽  
Transcriptional Analysis ◽  
Missense Mutations ◽  
Rapid Amplification ◽  
Translational Start ◽  
Carboxy Terminal

The molecular nature of a number of creA mutant alleles has been determined. Three alleles analysed are missense mutations in the DNA binding domain and predicted to reduce but not abolish binding. Of the other four alleles, two result from frameshifts: one has a nonsense mutation and the other has an inversion. All four alleles result in truncations of the protein after the zinc finger domain, such that the protein no longer contains at least the carboxy terminal 145 amino acids, so identifying a region required for repression. Transcriptional analysis of creA indicates that the transcript is autoregulated and analysis using 5′ rapid amplification of cDNA ends indicates that transcriptional start points exist in clusters over a region of 200 bp located up to 595 bp 5′ of the translational start point. The two major clusters have potential CREA-binding sites (SYGGRG) at appropriate positions to allow autoregulation. Autoregulation leads to the creA transcript being most abundant in carbon catabolite nonrepressing conditions, and this, together with the phenotypes of the mutant alleles, has led to the suggestion that CREA has effects under conditions generally not considered as carbon catabolite repressing, as well as in carbon catabolite repressing conditions.Key words: carbon catabolite repression, MIG1, CREA, zinc finger protein, transcriptional repressor.

scholarly journals Improvement of xylanase production by a parasexual cross between Aspergillus niger strains

2003 ◽  
Vol 46 (2) ◽  
pp. 177-181 ◽  
Author(s):  
Octavio Loera ◽  
Jesús Córdova
Keyword(s):  
Aspergillus Niger ◽  
Catabolite Repression ◽  
Type Strain ◽  
Wild Type Strain ◽  
Carbon Catabolite Repression ◽  
Wild Type ◽  
Diploid Strain ◽  
Xylanase Production ◽  
Parasexual Cycle ◽  
Xylanolytic Activity

A diploid strain (D4) isolated via parasexual recombination between two Aspergillus niger xylanase overproducing mutants was characterised in terms of enzyme production and catabolite repression by glucose. This strain increased xylanase production (607 nkat/ml), which was nearly 100% higher than titers achieved by the wild type strain (305 nkat/ml) and 28% higher than the best mutant used to induce parasexual cycle. Diploid D4 was also less sensitive to carbon catabolite repression by glucose, since xylanolytic activity was detected under conditions normally repressing production by the wild type strain. No decrease in maximal xylanase levels was observed in the presence of glucose for diploid D4.

Xylanase production inAspergillus nidulans: induction and carbon catabolite repression

1994 ◽  
Vol 115 (2-3) ◽  
pp. 319-323 ◽  
Author(s):  
F. Piñaga ◽  
M.T. Fernández-Espinar ◽  
S. Vallés ◽  
D. Ramón
Keyword(s):  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
Xylanase Production

Carbon catabolite repression gene creA regulates morphology, aflatoxin biosynthesis and virulence in Aspergillus flavus

2018 ◽  
Vol 115 ◽  
pp. 41-51 ◽  
Author(s):  
Opemipo Esther Fasoyin ◽  
Bin Wang ◽  
Mengguang Qiu ◽  
Xiaoyun Han ◽  
Kuang-Ren Chung ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
Aflatoxin Biosynthesis

scholarly journals Composition of Pseudomonas aeruginosa slime

1969 ◽  
Vol 112 (4) ◽  
pp. 521-525 ◽  
Author(s):  
M. R. W. Brown ◽  
J. H. Scott Foster ◽  
J. R. Clamp
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Hyaluronic Acid ◽  
Nucleic Acid ◽  
Growth Medium ◽  
Extraction Procedure ◽  
The Other ◽  
Minor Components ◽  
Polysaccharide Fraction ◽  
Defined Media ◽  
Rna And Dna

1. The slime produced by eight strains of Pseudomonas aeruginosa on a number of different media was demonstrated to be qualitatively the same. Small quantitative differences may be occasioned by differences in the extraction procedure, the growth medium or the strain of organism used. 2. The slime was shown to be predominantly polysaccharide with some nucleic acid material and a small amount of protein. 3. The hydrolysed polysaccharide fraction consists mainly of glucose with smaller amounts of mannose. This accounts for some 50–60% of the total slime. In addition, there is some 5% of hyaluronic acid. The nucleic acid material represents approx. 20% of the total weight, and is composed of both RNA and DNA. 4. Minor components are protein, rhamnose and glucosamine, the protein being less than 5% of the total. 5. Hyaluronic acid is produced in greater quantities from nutrient broth than from chemically defined media, and is more firmly attached to the cells than the other components.

Carbon catabolite repression occurrence in photo fermentation of ethanol-rich substrates

2021 ◽  
Vol 297 ◽  
pp. 113371
Author(s):  
Grazia Policastro ◽  
Marco Giugliano ◽  
Vincenzo Luongo ◽  
Raffaele Napolitano ◽  
Massimiliano Fabbricino
Keyword(s):  
Catabolite Repression ◽  
Carbon Catabolite Repression
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