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70 results on '"Eslava, Arturo P."'

61. Regulation of Carotene Biosynthesis in <em>Phycomyces</em> by Vitamin A and <em>β</em>-Ionone.

Author

Eslava, Arturo P., Alvarez, Maria I., and Cerdá-Olmedo, Enrique

Subjects
*VITAMIN A, *CAROTENES, *PHYCOMYCES blakesleeanus, *GENETIC mutation, *CHEMICAL kinetics, *MICROBIAL biotechnology
Abstract

The presence of vitamin A in the medium results in a large increase in Β-carotene content in wild-type Phycomyces blakesleeanus; in carB mutants. which accumulate phytoene. and carR mutants. which accumulate lycopene, the presence of vitamin A results in an increase in these intermediates. In carA mutants. which usually form no carotenoids. vitamin A partially counteracts the mutational block and allows Β-carotene synthesis. Vitamin A is not itself converted to Β-carotene. Β-ionone. long known as a stimulator of carotenogenesis, can also counteract carA mutations. The effects of vitamin A and Β-ionone do not occur in the presence of the protein-synthesis inhibitor cycloheximide. Vitamin A and Β-ionone stimulate carotenogenesis through the normal pathway. probably by interaction with the carA gene product. [ABSTRACT FROM AUTHOR]

Published
1974
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63. Double-stranded RNA and virus-like particles in the grass endophyte <e1>Epichloë festucae</e1> (I. Zabalgogeazcoa and others)

Author

ZABALGOGEAZCOA, IÑIGO, BENITO, ERNESTO P., CIUDAD, ANTONIA GARCIA, CRIADO, BALBINO GARCIA, and ESLAVA, ARTURO P.

Abstract

Two double-stranded ribonucleic acid (dsRNA) elements were detected in an isolate of the clavicipitaceous grass endophyte Epichloë festucae obtained from an asymptomatic Festuca rubra plant. No dsRNA was detected in three other isolates of E. festucae. The size of the two dsRNA elements isolated from mycelium was of 5·2 and 3·2 kbp. Hybridization experiments with a cDNA probe complementary to the 5·2 kbp dsRNA showed that there was no sequence similarity between the dsRNA elements. Isometric virus-like particles of about 50 nm in diameter were observed by electron microscopy in sucrose-gradient purified virus preparations from the isolate containing dsRNA. The 5·2 kbp dsRNA element was present in the partially purified virus preparations, suggesting that this element is encapsidated. There was no difference with respect to growth rate or colony morphology between the dsRNA containing and dsRNA-free isolates. The presence of dsRNA and virus-like particles suggests the presence of a mycovirus in the Vit5 strain of E. festucae.

Published
1998

64. Mapping of the RIB5 gene in Saccharomyces cerevisiae using UV light as an enhancer of rad52-mediated chromosome loss

Author

Angeles Santos, María, Iturriaga, Enrique A., and Eslava, Arturo P.

Abstract

Ribs mutants of S. cerevisiae are blocked at the end of the riboflavin biosynthetic pathway. Using UV light to increase rad52-mediated chromosome loss, we have assigned the rib5 mutation to chromosome II. Tetrad analysis of crosses between rib5 and other markers on chromosome II shows that the RIB5 gene is located on the right arm of this chromosome, closely linked to HIS7.

Published
1988
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70. Expression Vectors and Gene Fusions for the Directed Modification of the Carotenoid Biosynthesis Pathway in Mucor circinelloides.

Author

Iturriaga EA, Alvarez MI, Eslava AP, and Papp T

Subjects
Gene Order, Metabolic Engineering, Transformation, Genetic, Zeaxanthins biosynthesis, beta Carotene biosynthesis, Biosynthetic Pathways, Carotenoids biosynthesis, Gene Expression Regulation, Fungal, Gene Fusion, Mucor genetics, Mucor metabolism, Plasmids genetics
Abstract

Several fungal species, particularly some included in the Mucoromycotina, have been used to develop fermentation processes for the production of β-carotene. Oxygenated derivatives of β-carotene (xanthophylls) are desirable value-added products, and the preference by the market of carotenoids from biological sources has increased the research in different carotenoid-producing organisms. We currently use Mucor circinelloides f. lusitanicus as a model organism to develop strains with an increased content of new and more valuable carotenoids. The main carotenoid accumulated by M. circinelloides is β-carotene, although it has some hydroxylase activity and produces low amounts of zeaxanthin. On the other hand, in astaxanthin-producing organisms two enzymatic activities are required for the production of astaxanthin from β-carotene: a hydroxylase and a ketolase. In this chapter, we delineate part of our efforts to construct genetically modified strains that could advance in the improvement of carotenoid accumulation by this fungus and the diversification of its carotenoid content. Accordingly, we describe detailed and empirically tested protocols for the construction of functional expression vectors and gene fusions.

Published
2018
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