scholarly journals Studies in carotenogenesis. 15. The role of carboxylic acids in the biosynthesis of β-carotene by Phycomyces blakesleeanus*

1955 ◽  
Vol 60 (4) ◽  
pp. 649-655 ◽  
Author(s):  
J. Friend ◽  
T. W. Goodwin ◽  
L. A. Griffiths
Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 635-641
Author(s):  
Bina J Mehta ◽  
Enrique Cerdá-Olmedo

Abstract Sexual interaction between strains of opposite sex in many fungi of the order Mucorales modifies hyphal morphology and increases the carotene content. The progeny of crosses of Phycomyces blakesleeanus usually include a small proportion of anomalous segregants that show these signs of sexual stimulation without a partner. We have analyzed the genetic constitution of such segregants from crosses that involved a carF mutation for overaccumulation of β-carotene and other markers. The new strains were diploids or partial diploids heterozygous for the sex markers. Diploidy was unknown in this fungus and in the Zygomycetes. Random chromosome losses during the vegetative growth of the diploid led to heterokaryosis in the coenocytic mycelia and eventually to sectors of various tints and mating behavior. The changes in the nuclear composition of the mycelia could be followed by selecting for individual nuclei. The results impose a reinterpretation of the sexual cycle of Phycomyces. Some of the intersexual strains that carried the carF mutation contained 25 mg β-carotene per gram of dry mass and were sufficiently stable for practical use in carotene production.


2018 ◽  
Vol 61 ◽  
pp. 92-99 ◽  
Author(s):  
Lihui Zhou ◽  
Lian Ouyang ◽  
Shuangzhi Lin ◽  
Song Chen ◽  
YingJie Liu ◽  
...  

Synthesis ◽  
2020 ◽  
Author(s):  
Zbigniew Wróbel ◽  
Michał Tryniszewski ◽  
Robert Bujok ◽  
Roman Gańczarczyk

Tributyl- or triphenylphosphine promotes a one-pot, three-step method for the synthesis of differently substituted dibenzodiazepinones from N-aryl-2-nitroanilines. Pyridine analogues and the corresponding thiazepinones can also be formed using this method. The process involves deoxygenation of the nitro group, then formation of an iminophosphorane intermediate and its intramolecular condensation with a carboxyl group placed in the N-aryl group. The role of the carboxyl group in the formation of the iminophosphorane and the mode of cyclization are discussed.


2014 ◽  
Vol 81 ◽  
pp. 121-127 ◽  
Author(s):  
Kostas Stamatakis ◽  
Merope Tsimilli-Michael ◽  
George C. Papageorgiou

Mycologia ◽  
1958 ◽  
Vol 50 (6) ◽  
pp. 862-873
Author(s):  
Virgil Greene Lilly ◽  
H. L. Barnett ◽  
R. F. Krause ◽  
F. J. Lotspeich

2007 ◽  
Vol 282 (46) ◽  
pp. 33553-33561 ◽  
Author(s):  
Susanne Hessel ◽  
Anne Eichinger ◽  
Andrea Isken ◽  
Jaume Amengual ◽  
Silke Hunzelmann ◽  
...  

Carotenoids are currently investigated regarding their potential to lower the risk of chronic disease and to combat vitamin A deficiency in humans. These plant-derived compounds must be cleaved and metabolically converted by intrinsic carotenoid oxygenases to support the panoply of vitamin A-dependent physiological processes. Two different carotenoid-cleaving enzymes were identified in mammals, the classical carotenoid-15,15′-oxygenase (CMO1) and a putative carotenoid-9′,10′-oxygenase (CMO2). To analyze the role of CMO1 in mammalian physiology, here we disrupted the corresponding gene by targeted homologous recombination in mice. On a diet providing β-carotene as major vitamin A precursor, vitamin A levels fell dramatically in several tissues examined. Instead, this mouse mutant accumulated the provitamin in large quantities (e.g. as seen by an orange coloring of adipose tissues). Besides impairments in β-carotene metabolism, CMO1 deficiency more generally interfered with lipid homeostasis. Even on a vitamin A-sufficient chow, CMO1-/- mice developed a fatty liver and displayed altered serum lipid levels with elevated serum unesterified fatty acids. Additionally, this mouse mutant was more susceptible to high fat diet-induced impairments in fatty acid metabolism. Quantitative reverse transcription-PCR analysis revealed that the expression of peroxisome proliferator-activated receptor γ-regulated marker genes related to adipogenesis was elevated in visceral adipose tissues. Thus, our study identifies CMO1 as the key enzyme for vitamin A production and provides evidence for a role of carotenoids as more general regulators of lipid metabolism.


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