Isolation and characterization of pigmentation mutants of Micrococcus roseus

1974 ◽  
Vol 20 (7) ◽  
pp. 1007-1013 ◽  
Author(s):  
E. H. Schwartzel ◽  
J. J. Cooney
Keyword(s):  
Carotenoid Pigment ◽  
Pigment Composition ◽  
Wild Type ◽  
Total Carotenoids ◽  
Isolation And Characterization ◽  
Micrococcus Roseus ◽  
Β Carotene

A number of UV-induced pigmentation mutants of Micrococcus roseus were isolated. The carotenoid pigment composition of a yellow mutant and a pink mutant were determined and compared with the composition of the wild type. The yellow mutant appeared to have the ability to insert oxygen functions on only one end of β-carotene. The pink mutant formed less total carotenoids than the wild type; it formed diketo-carotenoids but no dihydroxy compounds. The results are discussed in relation to xanthophyll synthesis in M. roseus.

scholarly journals Isolation and characterization of the SPT2 gene, a negative regulator of Ty-controlled yeast gene expression.

1985 ◽  
Vol 5 (7) ◽  
pp. 1543-1553 ◽  
Author(s):  
G S Roeder ◽  
C Beard ◽  
M Smith ◽  
S Keranen
Keyword(s):  
Gene Product ◽  
Regulatory Region ◽  
Negative Regulator ◽  
Transcriptional Level ◽  
Wild Type ◽  
Isolation And Characterization ◽  
Mutant Strains ◽  
Insertion Mutations ◽  
His4 Gene

The his4-917 mutation of Saccharomyces cerevisiae results from the insertion of the Ty element Ty917 into the regulatory region of the HIS4 gene and renders the cell His-. The hist4-912 delta mutant, which carries a solo delta in the 5'-noncoding region of HIS4, is His+ at 37 degrees C but His- at 23 degrees C. Both these mutations interfere with HIS4 expression at the transcriptional level. The His- phenotype of both insertion mutations is suppressed by mutations at the SPT2 locus. The product of the wild-type SPT2 gene apparently represses HIS4 transcription in these mutant strains; this repression is relieved when the SPT2 gene is destroyed by mutation. The repression of transcription by SPT2 presumably results from an interaction between the SPT2+ gene product and Ty or delta sequences. In this paper, we report the cloning and DNA sequence analysis of the wild-type SPT2 gene and show that the gene is capable of encoding a protein of 333 amino acids in length. In addition, we show that a dominant mutation of the SPT2 gene results from the generation of an ochre codon which is presumed to lead to a shortened SPT2 gene product.

Isolation and characterization of cDNAs encoding β-carotene hydroxylase in Citrus

Plant Science ◽  
2001 ◽  
Vol 161 (5) ◽  
pp. 1005-1010 ◽  
Author(s):  
In-Jung Kim ◽  
Kyong-Cheol Ko ◽  
Chan-Shick Kim ◽  
Won-Il Chung
Keyword(s):  
Isolation And Characterization ◽  
Β Carotene

Isolation and characterization of Schizosaccharomyces pombe mutants with defective NAD-dependent malic enzyme

1986 ◽  
Vol 32 (6) ◽  
pp. 481-486 ◽  
Author(s):  
C. Osothsilp ◽  
R. E. Subden
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Malic Enzyme ◽  
Pool Analysis ◽  
Starch Gel Electrophoresis ◽  
Wild Type ◽  
Isolation And Characterization ◽  
Starch Gel ◽  
Colony Color ◽  
Color Indicator

To obtain NAD-dependent malic enzyme mutants of Schizosaccharomyces pombe, a colony color indicator screening system was developed. Mutants defective for malic acid utilization (mau mutants) are yellow, while wild-type colonies are blue on the defined bromcresol green based indicator medium. NAD-dependent malic enzyme mutants were distinguished from other mau mutants by subsequent, starch gel electrophoresis, spectrophotometry, complementation tests, and intermediate pool analysis with cell-free extracts.

scholarly journals Isolation and Characterization of Mutations in theEscherichia coli Regulatory Protein XapR

1999 ◽  
Vol 181 (14) ◽  
pp. 4397-4403 ◽  
Author(s):  
Casper Jørgensen ◽  
Gert Dandanell
Keyword(s):  
Amino Acids ◽  
Purine Nucleoside Phosphorylase ◽  
Mutational Analysis ◽  
Regulatory Protein ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Wild Type ◽  
Isolation And Characterization ◽  
In The Wild

ABSTRACT In this work, the LysR-type protein XapR has been subjected to a mutational analysis. XapR regulates the expression of xanthosine phosphorylase (XapA), a purine nucleoside phosphorylase inEscherichia coli. In the wild type, full expression of XapA requires both a functional XapR protein and the inducer xanthosine. Here we show that deoxyinosine can also function as an inducer in the wild type, although not to the same extent as xanthosine. We have isolated and characterized in detail the mutants that can be induced by other nucleosides as well as xanthosine. Sequencing of the mutants has revealed that two regions in XapR are important for correct interactions between the inducer and XapR. One region is defined by amino acids 104 and 132, and the other region, containing most of the isolated mutations, is found between amino acids 203 and 210. These regions, when modelled into the three-dimensional structure of CysB from Klebsiella aerogenes, are placed close together and are most probably directly involved in binding the inducer xanthosine.

scholarly journals Biflavonoids from the Unripe Fruits of Clusia Paralicola and their Antioxidant Activity

2012 ◽  
Vol 7 (12) ◽  
pp. 1934578X1200701 ◽  
Author(s):  
Rafaela Ferreira Oliveira ◽  
Celso Amorim Camara ◽  
Maria de Fátima Agra ◽  
Tania Maria Sarmento Silva
Keyword(s):  
Antioxidant Activity ◽  
Linoleic Acid ◽  
Spectral Data ◽  
2D Nmr ◽  
Cd Spectra ◽  
Total Extract ◽  
Isolation And Characterization ◽  
Β Carotene ◽  
Unripe Fruits

Investigation of the green fruits of Clusia paralicola (Clusiaceae) led to the isolation and characterization of two 3,8″-biflavonoids, 2R, 3S, 2″R, 3″R-GB1-7″- O-β-glucoside (1) and 2R, 3S, 2″R, 3,8″-binaringenin-7″-O-β-glucoside (2), together with four known compounds: β-sitosterol, stigmasterol, β-amyrin, and epicatechin. The structures were established from the IR, LC-ESI-MS and NMR spectral data, including 2D-NMR experiments. The absolute configurations of 1 and 2 were determined by CD spectra. The total extract and the biflavonoids demonstrated significant antioxidant activity in DPPH, ABTS, and β-carotene/linoleic acid tests.

scholarly journals ISOLATION AND CHARACTERIZATION OF CARBENDAZIM DEGRADING Trichoderma harzianum RIFAI MUTANTS

2010 ◽  
Vol 20 ◽  
Author(s):  
ITAMAR SOARES DE MELO ◽  
CÉLIA MARIA MAGANHOTTO DE S. SILVA ◽  
JANE L. FAULL
Keyword(s):  
Trichoderma Harzianum ◽  
Uv Light ◽  
Light Exposure ◽  
Wild Type ◽  
Pesticide Degradation ◽  
Isolation And Characterization ◽  
Degradation Ability

Mutants of Trichoderma harzianum Rifai, obtained after ultraviolet (UV) light exposure, showed high resistant to the fungicide benomyl. A mutant (2B6) was capable of degrading carbendazim, other fungicide of the benzimidazole fungicide. This mutant degraded 41.5% of the molecule within five days. This and others mutants (2B1 and 2B2) presented variation in size and frequency of uni-nucleated and/or bi-nucleated spores compared to the wild type. Four primers generated RAPDs patterns that allowed the mutant to be differentiated from the wild-type. It is concluded that using UV mutagenization, it is feasible to obtain strains of T. harzianum with improved pesticide degradation ability.

scholarly journals Overexpression of a Rice NPR1 Homolog Leads to Constitutive Activation of Defense Response and Hypersensitivity to Light

2005 ◽  
Vol 18 (6) ◽  
pp. 511-520 ◽  
Author(s):  
Mawsheng Chern ◽  
Heather A. Fitzgerald ◽  
Patrick E. Canlas ◽  
Duroy A. Navarre ◽  
Pamela C. Ronald
Keyword(s):  
Systemic Acquired Resistance ◽  
Environmental Changes ◽  
Acquired Resistance ◽  
Northern Analysis ◽  
Wild Type ◽  
Defense Genes ◽  
Isolation And Characterization ◽  
Broad Spectrum Resistance ◽  
Resistance Pathway

Arabidopsis NPR1/NIM1 is a key regulator of systemic acquired resistance (SAR), which confers lasting broad-spectrum resistance. Previous reports indicate that rice has a disease-resistance pathway similar to the Arabidopsis SAR pathway. Here we report the isolation and characterization of a rice NPR1 homologue (NH1). Transgenic rice plants overexpressing NH1 (NH1ox) acquire high levels of resistance to Xanthomonas oryzae pv. oryzae. The resistance phenotype is heritable and correlates with the presence of the transgene and reduced bacterial growth. Northern analysis shows that NH1ox rice spontaneously activates defense genes, contrasting with NPR1-overexpressing Arabidopsis, where defense genes are not activated until induction. Wild-type NH1, but not a point mutant corresponding to npr1-1, interacts strongly with the rice transcription factor rTGA2.2 in yeast two-hybrid. Greenhouse-grown NH1ox plants develop lesion-mimic spots on leaves at preflowering stage although no other developmental effects are observed. However, when grown in growth chambers (GCs) under low light, NH1ox plants are dwarfed, indicating elevated sensitivity to light. The GC-grown NH1ox plants show much higher salicylic acid (SA) levels than the wild type, whereas greenhouse-grown NH1ox plants contain lower SA. These results indicate that NH1 may be involved in the regulation of SA in response to environmental changes.

scholarly journals Isolation and characterization of regulatory mutants from Schizosaccharomyces pombe involved in thiamine-regulated gene expression.

Genetics ◽  
1992 ◽  
Vol 130 (3) ◽  
pp. 445-449
Author(s):  
A M Schweingruber ◽  
H Fankhauser ◽  
J Dlugonski ◽  
C Steinmann-Loss ◽  
M E Schweingruber
Keyword(s):  
Acid Phosphatase ◽  
Schizosaccharomyces Pombe ◽  
Mrna Levels ◽  
Wild Type ◽  
Transcription Control ◽  
Isolation And Characterization ◽  
Gene Coding ◽  
Thiamine Transport ◽  
Regulated Gene Expression

Abstract Mutants from Schizosaccharomyces pombe deficient in the regulation of thiamine-repressible acid phosphatase have been isolated. Mutants expressing derepressed levels of the enzyme in the presence and absence of thiamine map in three genes, tnr1, tnr2 and tnr3. mRNA levels of the pho4 gene (coding for thiamine repressible acid phosphatase) and another thiamine-regulatable gene, thi3 (coding for a thiamine biosynthetic enzyme and corresponding to nmt1) are constitutively synthesized in the mutants. The mutants also exhibit constitutive thiamine transport which is thiamine repressible in wild type. The tnr3 mutants reveal a 10-20-fold higher intracellular thiamine level than tnr1 and tnr2 mutants and wild type. Mutants expressing repressed levels of thiamine-repressible acid phosphatase map in gene thi1. No or little amounts of pho4- and nmt1-specific mRNA can be detected. These mutants are impaired in thiamine uptake and are thiamine auxotrophic due to the inability to synthesize the thiazole moiety of the thiamine molecule. All tested tnr and thi1 alleles are recessive, and thi1 mutations are epistatic over tnr mutations. We assume that the thi1 and tnr genes are involved in thiamine-mediated transcription control.

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