Overexpression of isocitrate lyase—glyoxylate bypass influence on metabolism in Aspergillus niger

2009 ◽  
Vol 11 (2) ◽  
pp. 107-116 ◽  
Author(s):  
S. Meijer ◽  
J. Otero ◽  
R. Olivares ◽  
M.R. Andersen ◽  
L. Olsson ◽  
...  
2005 ◽  
Vol 73 (10) ◽  
pp. 6736-6741 ◽  
Author(s):  
Daniel M. Wall ◽  
Pamela S. Duffy ◽  
Chris DuPont ◽  
John F. Prescott ◽  
Wim G. Meijer

ABSTRACT Rhodococcus equi is an important pathogen of foals, causing severe pyogranulomatous pneumonia. Virulent R. equi strains grow within macrophages, a process which remains poorly characterized. A potential source of carbon for intramacrophage R. equi is membrane lipid-derived fatty acids, which following β oxidation are assimilated via the glyoxylate bypass. To assess the importance of isocitrate lyase, the first enzyme of the glyoxylate bypass, in virulence of a foal isolate of R. equi, a mutant was constructed by a strategy of single homologous recombination using a suicide plasmid containing an internal fragment of the R. equi aceA gene encoding isocitrate lyase. Complementation of the resulting mutant with aceA showed that the mutant was specific for this gene. Assessment of virulence in a mouse macrophage cell line showed that the mutant was killed, in contrast to the parent strain. Studies in the liver of intravenously infected mice showed enhanced clearance of the mutant. When four 3-week-old foals were infected intrabronchially, the aceA mutant was completely attenuated, in contrast to the parent strain. In conclusion, the aceA gene was shown to be essential for virulence of R. equi, suggesting that membrane lipids may be an important source of carbon for phagocytosed R. equi.


1972 ◽  
Vol 128 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Patricia M. Dunstan ◽  
C. Anthony ◽  
W. T. Drabble

Pseudomonas AM1 grows on ethanol with a mean generation time of about 10h. A single alcohol dehydrogenase is responsible for oxidation of both methanol and ethanol. It is proposed that the glyoxylate bypass does not operate in Pseudomonas AM1 during growth on ethanol. Although malate synthase is present in extracts of ethanol-grown Pseudomonas AM1, the activity of isocitrate lyase is negligible. Short-term incubation experiments with [14C]ethanol and [14C]acetate indicate that a novel pathway operates during growth of Pseudomonas AM1 on ethanol. Glycollate, glyoxylate and malate are probably intermediates in this pathway.


1987 ◽  
Vol 242 (3) ◽  
pp. 661-665 ◽  
Author(s):  
E M T el-Mansi ◽  
C MacKintosh ◽  
K Duncan ◽  
W H Holms ◽  
H G Nimmo

A recombinant plasmid carrying an 11 kb restriction-endonuclease-ClaI fragment of genomic DNA from Escherichia coli ML308 was constructed. This plasmid complements an aceA mutation. The plasmid encodes the structural genes of the glyoxylate bypass operon, namely malate synthase A (aceB), isocitrate lyase (aceA) and isocitrate dehydrogenase kinase/phosphatase (aceK), as judged by overexpression of enzyme activities and transcription/translation experiments in vitro. Subcloning confirmed that expression of the aceK gene is essential for growth on acetate.


1986 ◽  
Vol 32 (7) ◽  
pp. 535-538 ◽  
Author(s):  
S. R. Sahasrabudhe ◽  
D. Lala ◽  
V. V. Modi

Aspergillus niger could utilize orcinol (5-methyl-resorcinol or 3,5-dihydroxytoluene) as the sole source of carbon and energy. In the first step of catabolism A. niger hydroxylates orcinol to form 2,3,5-trihydroxytoluene. Its oxidized form, 2-hydroxy-6-methyl-1,4-benzoquinone, was also formed in the culture medium during growth of this organism. Orcinol-grown cells showed a net increase in the intracellular acetate pool, compared with glucose-grown cells. Cell-free extracts of orcinol-grown cells showed higher activity of orcinol hydroxylase, catechol 1,2-oxygenase, and isocitrate lyase than that of glucose-grown cells. Both orcinol-grown and resorcinol-grown cells exhibit similar respiratory activity on all the substrates checked.


1969 ◽  
Vol 15 (10) ◽  
pp. 1207-1212 ◽  
Author(s):  
J. C. Galbraith ◽  
J. E. Smith

The activities of certain enzymes of the tricarboxylic acid (TCA) cycle and the glyoxylate cycle (GLC) varied during growth of Aspergillus niger as a function of the stage of the life cycle and of the growth medium. Isocitrate dehydrogenase (carboxylating) and isocitrate lyase each showed a marked increase in activity prior to sporulation. There were no similar increases in vegetative cultures. It is proposed that isocitrate lyase is functional in glycine synthesis and that a source of glyoxylate may be indispensable to the expression of sporulation.


2019 ◽  
Vol 49 (20) ◽  
Author(s):  
Nugroho Suharsono

Background: Fungal infection of the nose and paranasal sinuses is an uncommon condition which is now being increasingly recognized. The clinical presentation is not specific with various symptoms such as nasal obstruction, purulent nasal discharge, facial pain, and chronic cough. Only unilaterality may alert the clinician. Purpose: To find the morphological characteristics of the fungus in patients with paranasal sinus fungus ball. Methods: A retrospective study of 13 paranasal sinus fungus balls cases which underwent endoscopic sinus surgery at Department of Otorhinolaryngology Head and Neck Surgery St. Vincentius A Paulo Hospital Surabaya from March, 2012 until December, 2013. Age, sex, histopathology and fungal cultur were analysed. Histopathologic sections of all the patients were stained with hematoxylin and eosin (H&E), and Gomori methenamine silver (GMS). The specimens were then cultured on Sabouraud dextrose agar plates and incubated at 30°C for 1 month. At the end of the incubation period, the samples were evaluated microscopically to detect fungi and identify their species. Results: The age reported of the 13 patients, was ranging from 36 to 63 years old. There was a significant female predominance, 10 female patients (76.92%) and 3 male patients (23.08%). Histopathological examination showed that most causative agents were Aspergillus species 92.31% (12/13). Culture test was positive for 69.23% (9/13). Aspergillus niger (61.54%, 8/13) is the most frequent fungus reported to cause fungus balls. Conclusion: Pattern of histopathologic on HE and GMS is very helpful and sensitive to identify fungi. The most common isolated mould in our study was Aspergillus niger.Keywords: fungus ball, histopathology and culture, Aspergillus nigerABSTRAK Latar Belakang: Infeksi jamur di hidung dan sinus paranasal merupakan kondisi yang jarang terjadi, namun kini lebih sering ditemukan. Gejala klinisnya tidak spesifik dapat berupa obstruksi hidung, sekret dari hidung, nyeri wajah, dan batuk kronis. Bila terjadi unilateral, patut diwaspadai oleh para klinisi. Tujuan: Untuk mengetahui karakteristik morfologi fungus yang didapati pada pasien sinusitis jamur yang kami teliti. Metode: Dilakukan penelitian retrospektif pada 13 pasien sinusitis jamur yang menjalani bedah sinus endoskopi di Departemen Otorinolaringologi-Kepala Leher Rumah Sakit St. Vincentius A Paulo Surabaya dari bulan Maret 2012 sampai dengan Desember 2013. Dilakukan analisis usia, jenis kelamin, histopatologi dan kultur jamur. Pewarnaan preparat histopatologi menggunakan Hematoxylin dan eosin (H&E) dan Gomori Methenamine Silver (GMS). Kemudian spesimen diletakkan pada piring agar Sabouraud dextrose, dan dilakukan inkubasi pada suhu 30°C selama satu bulan. Pada akhir masa inkubasi, sampel dievaluasi dengan mikroskop untuk mendeteksi jamur dan spesiesnya. Hasil: Didapati usia 13 penderita berkisar dari 36-63 tahun. Wanita lebih dominan sebanyak 10 penderita (76,92 %) dan 3 penderita laki-laki (23,08%). Hasil pemeriksaan histopatologi menunjukkan spesies Aspergillus sebagai penyebab utama (92,31%) pada 12 penderita (12/13).Tes kultur positif pada 69,23% (9/13). Jamur yang paling sering menyebabkan bola jamur pada sinus adalah Aspergillus niger (61,54%, 8/13). Kesimpulan: Pewarnaan preparat histopatologi menggunakan Hematoxylin dan eosin (H&E) dan Gomori Methenamine Silver (GMS) sangat berguna dan sensitif dalam mendeteksi adanya jamur. Jenis jamur yang paling banyak ditemukan pada penelitian kami adalah Aspergillus niger.


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