scholarly journals Degradation of Diuron byPhanerochaete chrysosporium: Role of Ligninolytic Enzymes and Cytochrome P450

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Jaqueline da Silva Coelho-Moreira ◽  
Adelar Bracht ◽  
Aline Cristine da Silva de Souza ◽  
Roselene Ferreira Oliveira ◽  
Anacharis Babeto de Sá-Nakanishi ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Manganese Peroxidase ◽  
Culture Medium ◽  
Ligninolytic Enzymes ◽  
White Rot ◽  
White Rot Fungus ◽  
Metabolites Production ◽  
Herbicide Diuron

The white-rot fungusPhanerochaete chrysosporiumwas investigated for its capacity to degrade the herbicide diuron in liquid stationary cultures. The presence of diuron increased the production of lignin peroxidase in relation to control cultures but only barely affected the production of manganese peroxidase. The herbicide at the concentration of 7 μg/mL did not cause any reduction in the biomass production and it was almost completely removed after 10 days. Concomitantly with the removal of diuron, two metabolites, DCPMU [1-(3,4-dichlorophenyl)-3-methylurea] and DCPU [(3,4-dichlorophenyl)urea], were detected in the culture medium at the concentrations of 0.74 μg/mL and 0.06 μg/mL, respectively. Crude extracellular ligninolytic enzymes were not efficient in thein vitrodegradation of diuron. In addition, 1-aminobenzotriazole (ABT), a cytochrome P450 inhibitor, significantly inhibited both diuron degradation and metabolites production. Significant reduction in the toxicity evaluated by theLactuca sativaL. bioassay was observed in the cultures after 10 days of cultivation. In conclusion,P. chrysosporiumcan efficiently metabolize diuron without the accumulation of toxic products.

scholarly journals Calnexin Overexpression Increases Manganese Peroxidase Production in Aspergillus niger

2002 ◽  
Vol 68 (2) ◽  
pp. 846-851 ◽  
Author(s):  
Ana Conesa ◽  
David Jeenes ◽  
David B. Archer ◽  
Cees A. M. J. J. van den Hondel ◽  
Peter J. Punt
Keyword(s):  
Aspergillus Niger ◽  
Synergistic Effect ◽  
Phanerochaete Chrysosporium ◽  
Manganese Peroxidase ◽  
Culture Medium ◽  
White Rot ◽  
Expression Level ◽  
Prosthetic Group ◽  
Secretion Pathway

ABSTRACT Heme-containing peroxidases from white rot basidiomycetes, in contrast to most proteins of fungal origin, are poorly produced in industrial filamentous fungal strains. Factors limiting peroxidase production are believed to operate at the posttranslational level. In particular, insufficient availability of the prosthetic group which is required for peroxidase biosynthesis has been proposed to be an important bottleneck. In this work, we analyzed the role of two components of the secretion pathway, the chaperones calnexin and binding protein (BiP), in the production of a fungal peroxidase. Expression of the Phanerochaete chrysosporium manganese peroxidase (MnP) in Aspergillus niger resulted in an increase in the expression level of the clxA and bipA genes. In a heme-supplemented medium, where MnP was shown to be overproduced to higher levels, induction of clxA and bipA was also higher. Overexpression of these two chaperones in an MnP-producing strain was analyzed for its effect on MnP production. Whereas bipA overexpression seriously reduced MnP production, overexpression of calnexin resulted in a four- to fivefold increase in the extracellular MnP levels. However, when additional heme was provided in the culture medium, calnexin overexpression had no synergistic effect on MnP production. The possible function of these two chaperones in MnP maturation and production is discussed.

Ganoderma lucidum Polysaccharides: Immunomodulation and Potential Anti-Tumor Activities

2011 ◽  
Vol 39 (01) ◽  
pp. 15-27 ◽  
Author(s):  
Zengtao Xu ◽  
Xiuping Chen ◽  
Zhangfeng Zhong ◽  
Lidian Chen ◽  
Yitao Wang
Keyword(s):  
Ganoderma Lucidum ◽  
Tumor Therapy ◽  
White Rot ◽  
In Vivo Studies ◽  
White Rot Fungus ◽  
Bioactive Substances ◽  
Cytotoxic Effects

Ganoderma lucidum (G. lucidum), a basidiomycete white rot fungus, has long been prescribed to prevent and treat various human diseases, particularly in China, Japan, and Korea. Several classes of bioactive substances have been isolated and identified from G. lucidum, such as triterpenoids, polysaccharides, nucleosides, sterols, and alkaloids, among others. This paper examines the potential role of G. lucidum polysaccharide (GLPS) in tumor therapy and the possible mechanisms involved. Both in vitro and in vivo studies suggested that the anti-tumor activities of GLPS are mediated by its immunomodulatory, anti-angiogenic, and cytotoxic effects. GLPS affects immune cells and immune-related cells including B lymphocytes, T lymphocytes, dendritic cells, macrophages, and natural killer cells. In addition, recent data also suggest that GLPS suppresses tumorigenesis or inhibits tumor growth through direct cytotoxic effect and anti-angiogenic actions. However, many questions still need to be answered before both G. lucidum and GLPS can be widely accepted and used as anti-tumor agents.

scholarly journals Self-Sustaining Bioelectrochemical Cell from Fungal Degradation of Lignin-Rich Agrowaste

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2098
Author(s):  
Asiah Sukri ◽  
Raihan Othman ◽  
Firdaus Abd-Wahab ◽  
Noraini M. Noor
Keyword(s):  
Ligninolytic Enzymes ◽  
Linear Sweep Voltammetry ◽  
White Rot ◽  
White Rot Fungus ◽  
Air Electrode ◽  
Prolonged Duration ◽  
Specific Affinity ◽  
Metabolic Activities ◽  
Laccase Enzyme

The present work describes a self-sustaining bioelectrochemical system that adopts simple cell configurations and operates in uncontrolled ambient surroundings. The microbial fuel cell (MFC) was comprised of white-rot fungus of Phanaerochaete chrysosporium fed with oil palm empty fruit bunch (EFB) as the substrate. This fungal strain degrades lignin by producing ligninolytic enzymes such as laccase, which demonstrates a specific affinity for oxygen as its electron acceptor. By simply pairing zinc and the air electrode in a membraneless, single-chamber, 250-mL enclosure, electricity could be harvested. The microbial zinc/air cell is capable of sustaining a 1 mA discharge current continuously for 44 days (i.e., discharge capacity of 1056 mAh). The role of the metabolic activities of P. chrysosporium on EFB towards the MFC’s performance is supported by linear sweep voltammetry measurement and scanning electron microscopy observations. The ability of the MFC to sustain its discharge for a prolonged duration despite the fungal microbes not being attached to the air electrode is attributed to the formation of a network of filamentous hyphae under the submerged culture. Further, gradual lignin decomposition by fungal inocula ensures a continuous supply of laccase enzyme and radical oxidants to the MFC. These factors promote a self-sustaining MFC devoid of any control features.

scholarly journals Role of Organic Acids in the Manganese-Independent Biobleaching System of Bjerkandera sp. Strain BOS55

1998 ◽  
Vol 64 (7) ◽  
pp. 2409-2417 ◽  
Author(s):  
María Teresa Moreira ◽  
Gumersindo Feijoo ◽  
Tünde Mester ◽  
Pablo Mayorga ◽  
Reyes Sierra-Alvarez ◽  
...  
Keyword(s):  
Organic Acids ◽  
Manganese Peroxidase ◽  
Superoxide Anion ◽  
Kraft Pulp ◽  
Veratryl Alcohol ◽  
White Rot ◽  
White Rot Fungus ◽  
Ph Buffering ◽  
Enhanced Production

ABSTRACT Bjerkandera sp. strain BOS55 is a white rot fungus that can bleach EDTA-extracted eucalyptus oxygen-delignified kraft pulp (OKP) without any requirement for manganese. Under manganese-free conditions, additions of simple physiological organic acids (e.g., glycolate, glyoxylate, oxalate, and others) at 1 to 5 mM stimulated brightness gains and pulp delignification two- to threefold compared to results for control cultures not receiving acids. The role of the organic acids in improving the manganese-independent biobleaching was shown not to be due to pH-buffering effects. Instead, the stimulation was attributed to enhanced production of manganese peroxidase (MnP) and lignin peroxidase (LiP) as well as increased physiological concentrations of veratryl alcohol and oxalate. These factors contributed to greatly improved production of superoxide anion radicals, which may have accounted for the more extensive biobleaching. Optimum biobleaching corresponded most to the production of MnP. These results suggest that MnP from Bjerkandera is purposefully produced in the absence of manganese and can possibly function independently of manganese in OKP delignification. LiP probably also contributed to OKP delignification when it was present.

scholarly journals Biodegradation of atrazine and ligninolytic enzyme production by basidiomycete strains 

2020 ◽  
Author(s):  
Caroline Henn ◽  
Diego Alves Monteiro ◽  
Mauricio Boscolo ◽  
Roberto da Silva ◽  
Eleni Gomes
Keyword(s):  
Culture Medium ◽  
Nitrogen Availability ◽  
Ligninolytic Enzymes ◽  
Ligninolytic Enzyme ◽  
Pycnoporus Sanguineus ◽  
Fungal Metabolism ◽  
Key Aspects

Abstract Background Atrazine is one of the most widespread chlorinated herbicides, leaving large bulks in soils and groundwater. The biodegradation of atrazine by bacteria is well described, but many aspects of the fungal metabolism of this compound remain unclear. Thus, we investigated the toxicity and degradation of atrazine by 13 rainforest basidiomycete strains. Results In liquid medium, Pluteus cubensis SXS320, Gloelophyllum striatum MCA7, and Agaricales MCA17 removed 30, 37, and 38%, respectively, of initial 25 mg L-1 of the herbicide within 20 days. Deficiency of nitrogen drove atrazine degradation by Pluteus cubensis SXS320; this strain removed 30% of atrazine within 20 days in a culture medium with 2.5 mM of N, raising three metabolites; in a medium with 25 mM of N, only 21% of initial atrazine were removed after 40 days, and two metabolites appeared in culture extracts. This is the first report of such different outcomes linked to nitrogen availability during the biodegradation of atrazine by basidiomycetes. The herbicide also induced synthesis and secretion of extracellular laccases by Datronia caperata MCA5, Pycnoporus sanguineus MCA16, and Polyporus tenuiculus MCA11. Laccase levels produced by of P. tenuiculus MCA11 were 13.3-fold superior in the contaminated medium than in control; the possible role of this enzyme on atrazine biodegradation was evaluated, considering the strong induction and the removal of 13.9% of the herbicide in vivo. Although 88% of initial laccase activity remained after 6 h, no evidence of in vitro degradation was observed, even though ABTS was present as mediator. Conclusions This study revealed a high potential for atrazine biodegradation among tropical basidiomycete strains. Further investigations, focusing on less explored ligninolytic enzymes and cell-bound mechanisms, could enlighten key aspects of the atrazine fungal metabolism and the role of the nitrogen in the process.

Follicle-stimulating hormone-dependent estrogen secretion by rat Sertoli cells in vitro: Modulation by calcium

1991 ◽  
Vol 125 (3) ◽  
pp. 280-285 ◽  
Author(s):  
J. Alan Talbot ◽  
Ann Lambert ◽  
Robert Mitchell ◽  
Marek Grabinski ◽  
David C. Anderson ◽  
...  
Keyword(s):  
Sertoli Cells ◽  
Culture Medium ◽  
Follicle Stimulating Hormone ◽  
Dibutyryl Camp ◽  
Immature Rat ◽  
Estradiol Secretion ◽  
Old Rats ◽  
Stimulating Hormone

Abstract We have investigated the role of Ca2+ in the control of FSH-induced estradiol secretion by Sertoli cells isolated from 8-10 days old rats. Exogenous Ca2+ (4-8 mmol/1) inhibited FSH-stimulated E2 secretion such that, with 8 mmol/l Ca2+ and FSH (8 IU/l) E2 secretion decreased from 2091±322 to 1480±84 pmol/l (p<0.002), whilst chelation of Ca2+ in the culture medium with EGTA (3 mmol/l) increased E2 secretion from 360±45 to 1242±133 pmol/l) in the absence of FSH. Further, EGTA (3 mmol/l) markedly potentiated FSH (8 IU/l), forskolin (1 μmol/l) and dibutyryl cAMP (1 mmol/l)-stimulated E2 secretion. Addition of the Ca2+ ionophores, ionomycin (2-5 μmol/l) and A23187 (2 μmol/l), inhibited FSH (8 IU/l)-stimulated E2 secretion by >80%. The effect of ionomycin was totally reversible, whereas that of A23187 was irreversible. Ionomycin (5 μmol/l) had no effect on EGTA-induced E2 secretion in the absence of FSH, but reduced EGTA-provoked E2 secretion by 59% in the presence of FSH (8 IU/l). Similarly, forskolin- and dibutyryl cAMP-provoked E2 production was inhibited 46-50% by ionomycin (5 μmol/l). We conclude that FSH-induced E2 secretion from immature rat Sertoli cells is modulated by intra- and extracellular Ca2+.

Synergistic Methodology Based on Ion Exchange and Biodegradation Mechanisms Applied for Metal Complex Dye Removal from Waste Waters

2018 ◽  
Vol 69 (1) ◽  
pp. 38-44
Author(s):  
Nicoleta Mirela Marin ◽  
Olga Tiron ◽  
Luoana Florentina Pascu ◽  
Mihaela Costache ◽  
Mihai Nita Lazar ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Synergistic Effects ◽  
Freundlich Isotherm ◽  
White Rot ◽  
White Rot Fungus ◽  
Basic Anion Exchange Resin ◽  
Km Value ◽  
Points Of View ◽  
Basic Anion

This study investigates the synergistic effects of ion exchange and biodegradation methods to remove the Acid Blue 193 also called Gryfalan Navy Blue RL (GNB) dye from wastewater. Ion exchange studies were performed using a strongly basic anion exchange resin Amberlite IRA 400. The equilibrium was characterized by a kinetic and thermodynamic points of view, establishing that the sorption of the GNB dye was subject to the Freundlich isotherm model with R2 = 0.8710. Experimental results showed that the activated resin can removed up to 93.4% when the concentration of dye solution is 5.62�10-2 mM. The biodegradation of the GNB was induced by laccase, an enzyme isolated from white-rot fungus. It was also analyzed the role of pH and dye concentration on GNB biodegradation, so 5�10-2 mM dye had a maximum discoloration efficiency of 82.9% at pH of 4. The laccase showed a very fast and robust activity reaching in a few minutes a Km value of 2.2�10-1mM. In addition, increasing the GNB concentration up to 8�10-1 mM did not triggered a substrat inhibition effect on the laccase activity. Overall, in this study we proposed a mixt physicochemical and biological approach to enhance the GNB removal and biodegradability from the wastewaters and subsequently the environment.

scholarly journals Pathways of Carbamazepine Bioactivation in Vitro. III. The Role of Human Cytochrome P450 Enzymes in the Formation of 2,3-Dihydroxycarbamazepine

2008 ◽  
Vol 36 (8) ◽  
pp. 1637-1649 ◽  
Author(s):  
Robin E. Pearce ◽  
Wei Lu ◽  
YongQiang Wang ◽  
Jack P. Uetrecht ◽  
Maria Almira Correia ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Cytochrome P450 Enzymes ◽  
Human Cytochrome
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