21-Hydroxypregnane 21-O-malonylation, a crucial step in cardenolide biosynthesis, can be achieved by substrate-promiscuous BAHD-type phenolic glucoside malonyltransferases from Arabidopsis thaliana and homolog proteins from Digitalis lanata

Abstract Key message Studying RNAi-mediated DlP5βR1 and DlP5βR2 knockdown shoot culture lines of Digitalis lanata, we here provide direct evidence for the participation of PRISEs (progesterone 5β-reductase/iridoid synthase-like enzymes) in 5β-cardenolide formation. Abstract Progesterone 5β-reductases (P5βR) are assumed to catalyze the reduction of progesterone to 5β-pregnane-3,20-dione, which is a crucial step in the biosynthesis of the 5β-cardenolides. P5βRs are encoded by VEP1-like genes occurring ubiquitously in embryophytes. P5βRs are substrate-promiscuous enone-1,4-reductases recently termed PRISEs (progesterone 5β-reductase/iridoid synthase-like enzymes). Two PRISE genes, termed DlP5βR1 (AY585867.1) and DlP5βR2 (HM210089.1) were isolated from Digitalis lanata. To give experimental evidence for the participation of PRISEs in 5β-cardenolide formation, we here established several RNAi-mediated DlP5βR1 and DlP5βR2 knockdown shoot culture lines of D. lanata. Cardenolide contents were lower in D. lanata P5βR-RNAi lines than in wild-type shoots. We considered that the gene knockdowns may have had pleiotropic effects such as an increase in glutathione (GSH) which is known to inhibit cardenolide formation. GSH levels and expression of glutathione reductase (GR) were measured. Both were higher in the Dl P5βR-RNAi lines than in the wild-type shoots. Cardenolide biosynthesis was restored by buthionine sulfoximine (BSO) treatment in Dl P5βR2-RNAi lines but not in Dl P5βR1-RNAi lines. Since progesterone is a precursor of cardenolides but can also act as a reactive electrophile species (RES), we here discriminated between these by comparing the effects of progesterone and methyl vinyl ketone, a small RES but not a precursor of cardenolides. To the best of our knowledge, we here demonstrated for the first time that P5βR1 is involved in cardenolide formation. We also provide further evidence that PRISEs are also important for plants dealing with stress by detoxifying reactive electrophile species (RES).

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Letter Verbal Fluency in Spanish-, Basque-, and Catalan-Speaking Individuals: Does the Selection of the Letters Influence the Outcome?

Journal of Speech Language and Hearing Research ◽

10.1044/2019_jslhr-l-18-0365 ◽

2019 ◽

Vol 62 (7) ◽

pp. 2400-2410

Author(s):

Laiene Olabarrieta-Landa ◽

Itziar Benito-Sánchez ◽

Montserrat Alegret ◽

Anna Gailhajanet ◽

Esther Landa Torre ◽

...

Keyword(s):

Frontal Lobe ◽

Verbal Fluency ◽

Native Language ◽

Spanish Speakers ◽

Crucial Step ◽

Verbal Fluency Test ◽

Performance Differences ◽

Frontal Lobe Functioning ◽

Selection Of ◽

Fluency Test

Purpose The aim of this study was to compare Basque and Catalan bilinguals' performance on the letter verbal fluency test and determine whether significant differences are present depending on the letters used and the language of administration. Method The sample consisted of 87 Spanish monolinguals, 139 Basque bilinguals, and 130 Catalan bilinguals from Spain. Participants completed the letter verbal fluency test using the letters F, A, S, M, R, P, and E. Results Bilinguals scored higher on the letter verbal fluency test when they were tested in Spanish than in Basque or Catalan. No performance differences were found according to native language or dialects within Basque participants. Catalans with Spanish as their native language scored lower on the letter F compared to those who grew up speaking Catalan and Spanish. The suggested letters to use with Basque speakers are A, E, and B; the suggested letters to use with Catalan speakers are P, F, and M; and the suggested letters to use with Spanish speakers are M, R, and P. Conclusion Selecting appropriate stimuli depending on the language of testing is the first crucial step to assess verbal fluency and thus possible frontal lobe functioning impairment.

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