Cloning and characterization of oah, the gene encoding oxaloacetate hydrolase in Aspergillus niger

Abstract Aspergillus niger possesses a galactofuranosidase activity, however, the corresponding enzyme or gene encoding this enzyme has never been identified. As evidence is mounting that enzymes exist with affinity for both arabinofuranose and galactofuranose, we investigated the possibility that α-l-arabinofuranosidases, encoded by the abfA and abfB genes, are responsible for the galactofuranosidase activity of A. niger. Characterization of the recombinant AbfA and AbfB proteins revealed that both enzymes do not only hydrolyze p-nitrophenyl-α-l-arabinofuranoside (pNp-α-Araf) but are also capable of hydrolyzing p-nitrophenyl-β-d-galactofuranoside (pNp-β-Galf). Molecular modeling of the AbfB protein with pNp-β-Galf confirmed the possibility for AbfB to interact with this substrate, similarly as with pNp-α-Araf. We also show that galactomannan, a cell wall compound of A. niger, containing β-linked terminal and internal galactofuranosyl moieties, can be degraded by an enzyme activity that is present in the supernatant of inulin-grown A. niger. Interestingly, purified AbfA and AbfB did not show this hydrolyzing activity toward A. nigergalactomannan. In summary, our studies demonstrate that AbfA and AbfB, α-l-arabinofuranosidases from different families, both contain a galactofuranose (Galf)-hydrolyzing activity. In addition, our data support the presence of a Galf-hydrolase activity expressed by A. niger that is capable of degrading fungal galactomannan.

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Overexpression of the gene encoding alternative oxidase for enhanced glucose consumption in oxalic acid producing Aspergillus niger expressing oxaloacetate hydrolase gene

Journal of Bioscience and Bioengineering ◽

10.1016/j.jbiosc.2019.08.014 ◽

2020 ◽

Vol 129 (2) ◽

pp. 172-176

Author(s):

Isato Yoshioka ◽

Keiichi Kobayashi ◽

Kohtaro Kirimura

Keyword(s):

Aspergillus Niger ◽

Oxalic Acid ◽

Alternative Oxidase ◽

Glucose Consumption ◽

Gene Encoding ◽

Oxaloacetate Hydrolase

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Isolation and characterization of two specific regulatory Aspergillus niger mutants shows antagonistic regulation of arabinan and xylan metabolism

Microbiology ◽

10.1099/mic.0.25993-0 ◽

2003 ◽

Vol 149 (5) ◽

pp. 1183-1191 ◽

Cited By ~ 39

Author(s):

Marco J. L. de Groot ◽

Peter J. I. van de Vondervoort ◽

Ronald P. de Vries ◽

Patricia A. vanKuyk ◽

George J. G. Ruijter ◽

...

Keyword(s):

Aspergillus Niger ◽

Regulatory System ◽

Gene Encoding ◽

Isolation And Characterization ◽

Catabolic Genes ◽

Genes Encoding ◽

Intracellular Activities ◽

Xylulose Kinase ◽

Encoding Genes

This paper describes two Aspergillus niger mutants (araA and araB) specifically disturbed in the regulation of the arabinanase system in response to the presence of l-arabinose. Expression of the three known l-arabinose-induced arabinanolytic genes, abfA, abfB and abnA, was substantially decreased or absent in the araA and araB strains compared to the wild-type when incubated in the presence of l-arabinose or l-arabitol. In addition, the intracellular activities of l-arabitol dehydrogenase and l-arabinose reductase, involved in l-arabinose catabolism, were decreased in the araA and araB strains. Finally, the data show that the gene encoding d-xylulose kinase, xkiA, is also under control of the arabinanolytic regulatory system. l-Arabitol, most likely the true inducer of the arabinanolytic and l-arabinose catabolic genes, accumulated to a high intracellular concentration in the araA and araB mutants. This indicates that the decrease of expression of the arabinanolytic genes was not due to lack of inducer accumulation. Therefore, it is proposed that the araA and araB mutations are localized in positive-acting components of the regulatory system involved in the expression of the arabinanase-encoding genes and the genes encoding the l-arabinose catabolic pathway.

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Genomic Cloning and Characterization of a FIP-gsi Gene Encoding a Fungal Immunomodulatory Protein from Ganoderma sinense Zhao et al. (Aphyllophoromycetideae)

International Journal of Medicinal Mushrooms ◽

10.1615/intjmedmushr.v11.i1.90 ◽

2009 ◽

Vol 11 (1) ◽

pp. 77-86 ◽

Cited By ~ 24

Author(s):

Xuanwei Zhou ◽

Minqi Xie ◽

Fan Hong ◽

Qizhang Li ◽

Juan Lin

Keyword(s):

Gene Encoding ◽

Genomic Cloning ◽

Fungal Immunomodulatory Protein ◽

Immunomodulatory Protein ◽

Ganoderma Sinense

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Phylogeny Characterization of Seb Gene Encoding Enterotoxins in Staphylococcus aureus Isolated from Raw Milk and Cheese

International Journal of Drug Delivery Technology ◽

10.25258/ijddt.v9i3.13 ◽

2019 ◽

Vol 9 (o3) ◽

Author(s):

Fatima N. Aziz ◽

Laith Abdul Hassan Mohammed-Jawad

Keyword(s):

Staphylococcus Aureus ◽

Food Poisoning ◽

Raw Milk ◽

Staphylococcal Enterotoxin B ◽

Human Pathogen ◽

Conventional Pcr ◽

Biochemical Tests ◽

Specific Primers ◽

Gene Encoding

Food poisoning due to the bacteria is a big global problem in economically and human's health. This problem refers to an illness which is due to infection or the toxin exists in nature and the food that use. Milk is considered a nutritious food because it contains proteins and vitamins. The aim of this study is to detect and phylogeny characterization of staphylococcal enterotoxin B gene (Seb). A total of 200 milk and cheese samples were screened. One hundred ten isolates of Staphylococcus aureus pre-confirmed using selective and differential media with biochemical tests. Genomic DNA was extracted from the isolates and the SEB gene detects using conventional PCR with specific primers. Three staphylococcus aureus isolates were found to be positive for Seb gene using PCR and confirmed by sequencing. Sequence homology showed variety range of identity starting from (100% to 38%). Phylogenetic tree analyses show that samples (6 and 5) are correlated with S. epidermidis. This study discovered that isolates (A6-RLQ and A5-RLQ) are significantly clustered in a group with non- human pathogen Staphylococcus agnetis.

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