Localization of Enzymes of Oxalate Biosynthesis in Microbodies of Sclerotium rolfsii

Armentrout, V. N.

doi:10.1094/phyto-68-1597

Cited by 14 publications

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“…Glyoxylate dehydrogenase is assumed to be the key enzyme of oxalic acid synthesis [13]. The enzyme was characterized and located in microbodies of Sclerotium rolfsii [2]. Although another oxalic acid synthetic enzyme named glycolate oxidase has already been investigated in animals, plants, and microorganisms [22] and is even used for commercial applications [1], yet little is known about its role in oxalic acid synthesis in Sclerotium rolfsii.…”

Section: Introductionmentioning

confidence: 99%

Repression of oxalic acid biosynthesis in the unsterile scleroglucan production process with Sclerotium rolfsii ATCC 15205

Schilling¹,

Henning²,

Rau³

2000

Bioprocess Engineering

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Oxalic acid is the predominant by-product formed in the scleroglucan production process with Sclerotium rolfsii, representing an additional cost factor for the subsequent downstream processing. In this study, the formation of oxalic acid was substantially reduced using a low initial pH and oxygen limitation during batch cultivation. At an initial pH of 2.0 only traces of oxalic acid were determined in the culture medium (end concentration <0.5 g l A1 ) while the scleroglucan production remained unaffected. In addition, it was observed that oxalic acid formation ceased under oxygen limitation. This is due to a not yet described oxalic acid synthetic enzyme named glycolate oxidase (EC 1.1.3.15) which was identi®ed in cell-free extracts of Sclerotium rolfsii and further characterized. The in¯uence of the dissolved oxygen tension (DOT) on oxalic acid synthesis by the fungus was studied in continuous culture. The steady-state oxalic acid concentration in the culture medium increased with a rise in DOT. List of symbolsimpeller speed pO 2 % oxygen partial pressure in the liquid phaseAbbreviations DOT dissolved oxygen tension FMN¯avin mononucleotide TCA tricarboxylic acid IntroductionThe ®lamentously growing fungus Sclerotium rolfsii ATCC 15205 and related species secrete a water soluble b-1,3-glucan, branched at b-1,6. Microbial glucans experience an increasing interest in the cosmetic and pharmaceutical industry [10]. Their high speci®c viscosities provide a potential application as a viscosi®er in cosmetic creams or lotions [6]. The exhibition of anti-in¯ammatory and immune stimulatory properties of scleroglucan renders it valuable for a potential use as a drug [14,23]. The predominant by-product in scleroglucan production with Sclerotium rolfsii is oxalic acid. The amount of oxalic acid accumulated during batch cultivations can reach up to 6 g l A1 [15]. Therefore, considerable attention has to be paid to the factors stimulating oxalic acid biosynthesis. There have been several reports on the in¯uence of culture conditions on oxalic acid formation [11,12,26,27]. High initial pH values were observed to favor oxalic acid and glucan production while a low initial pH resulted in oxalic acid reduction accompanied by poor growth. Oxalic acid is also known to play a key role in the plant pathogenicity of Sclerotium rolfsii [3,8,17,28,29]. Glyoxylate dehydrogenase is assumed to be the key enzyme of oxalic acid synthesis [13]. The enzyme was characterized and located in microbodies of Sclerotium rolfsii [2]. Although another oxalic acid synthetic enzyme named glycolate oxidase has already been investigated in animals, plants, and microorganisms [22] and is even used for commercial applications [1], yet little is known about its role in oxalic acid synthesis in Sclerotium rolfsii. Materials and methods Microorganism and conditions of cultivationCultivations were carried out with the fungus imperfectus Sclerotium rolfsii ATCC 15205. The plant pathogenic, ®l-amentous fungus was grown on agar slants supplemented with 39 g l A1 po...

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Section: Introductionmentioning

confidence: 99%

Repression of oxalic acid biosynthesis in the unsterile scleroglucan production process with Sclerotium rolfsii ATCC 15205

Schilling¹,

Henning²,

Rau³

2000

Bioprocess Engineering

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“…These fungi produce and secrete oxalic acid that, during the infection process, acts in the degradation of the plant cell wall. Two key enzymes in the production of oxalate (isocitrate lyase and glyoxylate dehydrogenase) are located in the peroxisomes [ 56 ]. In human disorders, microbodies are related to peroxisomal dysfunction, such as cerebrohepatorenal (Zellweger) syndrome, Refsum disease, adrenoleukodystrophy, and acatalasaemia [ 57 ].…”

Section: Discussionmentioning

confidence: 99%

mus-52 disruption and metabolic regulation in Neurospora crassa: Transcriptional responses to extracellular phosphate availability

et al. 2018

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Advances in the understanding of molecular systems depend on specific tools like the disruption of genes to produce strains with the desired characteristics. The disruption of any mutagen sensitive (mus) genes in the model fungus Neurospora crassa, i.e. mus-51, mus-52, or mus-53, orthologous to the human genes KU70, KU80, and LIG4, respectively, provides efficient tools for gene targeting. Accordingly, we used RNA-sequencing and reverse transcription-quantitative polymerase chain reaction amplification techniques to evaluate the effects of mus-52 deletion in N. crassa gene transcriptional modulation, and thus, infer its influence regarding metabolic response to extracellular availability of inorganic phosphate (Pi). Notably, the absence of MUS-52 affected the transcription of a vast number of genes, highlighting the expression of those coding for transcription factors, kinases, circadian clocks, oxi-reduction balance, and membrane- and nucleolus-related proteins. These findings may provide insights toward the KU molecular mechanisms, which have been related to telomere maintenance, apoptosis, DNA replication, and gene transcription regulation, as well as associated human conditions including immune system disorders, cancer, and aging.

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“…These precursors may arise from the glycolate pathway (I.e., photorespiration; Tolbert, 1973), the glyoxylate bypass (Romberg and Krebs, 1957) or ureide metabolism from purine degradation (Huang, 1982). Certain pathological fungi oxidize glyoxalate to oxalic acid in the presence of NAD-glyoxalate dehydrogenease (Armentrout et al, 1978) but this system has not been demonstrated in any plant species (Huang, 1982). Therefore, in higher plants the conversion of glycolate to glyoxy late, and subsequently to oxalate, is mediated exclusively by peroxisomal glycolate oxidase (Tolbert, 1980;Huang, 1982).…”

Section: Henry David Thoreaumentioning

confidence: 99%

The development, physiology, and function of selected plant calcium oxalate crystal idioblasts

Kausch¹

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Oxalic acid is a dicarboxylic acid [(COOH)^], produced in plants through at least five biochemical pathways (Hodgkinson, 1977; Franceschi and Homer, 1980a). Oxalate has been reported to originate in some plants via enzymatic cleavage of oxaloacetate (Chang and Beevers, 1968) and/or ascorbate metabolism (Wagner and Loewus, 1973). However, it is generally accepted that the major intermediate precursors of oxalate in higher plants are glycolate and glyoxalate (Kpodar et al., 1978). These pre cursors may arise from the glycolate pathway (i.e., photorespiration; Tolbert, 1973), the glyoxalate bypass (Romberg and Krebs, 1957) or purine degradation (Huang, 1982). Certain plant pathological fungi oxidize glyoxalate to oxalic acid in the presence of peroxisonal NAD-glyoxalate dehydrogenase (Armentrout et al., 1978) but this system is not found in any higher plant species (Huang, 1982). Salient features of oxalate syn thetic pathways in plant cells provide a necessary background for this dissertation on calcium oxalate crystal idioblast biology. The glycolate pathway Glycolate arises as a result of photosynthesis (Tolbert, 1973) and is the principal substrate of photorespiration (Tolbert, 1973; Zelitch, 1975a,b) as the starting point of the glycolate pathway. Its formation is Og and light dependent and inhibited in high CO^ concentration, although the exact route of its production is not entirely clear (Zelitch, 1971). Glycolic acid is one of the first formed products of photosynthesis in 8 other than 0^. This enzume in barley is somevAiat unstable; all activity may be lost after three hours of dialysis (Kolesnikov et al., 1959). Richardson and Tolbert (1961) found that the activity of glycolate oxidase in spinach is not necessarily restricted to oxidizing glycolate to glyoxylate ^ vivo, but under specific cellular conditions, glyoxylate is oxidized to oxalate. Furthermore, they showed that the flavin-linked enzyme was competitively inhibited by oxalate. They implied that this provided for the regulation of oxalate synthesis. The Michaelis-Menten plots also show that the enzyme had a greater affinity for glycolate than for glyoxylate. Millerd et al. (1963d) found that glycolate oxidase from Oxalis was not affected by the presence of oxalate and had no preferential affinity for glycolate or glyoxylate. It may be that ^ vivo, the activity of glyoxyl ate oxidation may be high if oxalate is removed from the reaction site. A number of fates may befall the glyoxylate produced from photosynthetically derived glycolate in the glycolate oxidase reaction. It may return to the chloroplast to be reduced to glycolate by glycolate reductase (Zelitch, 1953) so that a glycolate-glyoxylate shuttle between the peroxisome and chloroplast is established (Carles and Assailly, 1954). Ifiich of the glyoxylates produced from the oxidation of glycolate is transaminated to glycine in the presence of glutamic acid (Richardson and Tolbert, 1961). Glycine may give rise to serine and CO^ by a hydroxymethyltransferase reaction (Tolbert and Cohan, 1953)....

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Localization of Enzymes of Oxalate Biosynthesis in Microbodies of Sclerotium rolfsii

Cited by 14 publications

References 0 publications

Repression of oxalic acid biosynthesis in the unsterile scleroglucan production process with Sclerotium rolfsii ATCC 15205

Repression of oxalic acid biosynthesis in the unsterile scleroglucan production process with Sclerotium rolfsii ATCC 15205

mus-52 disruption and metabolic regulation in Neurospora crassa: Transcriptional responses to extracellular phosphate availability

The development, physiology, and function of selected plant calcium oxalate crystal idioblasts

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