Search Results (3)

Drought resistance in plants is controlled by multiple genes. To identify the genes that mediate drought stress responses and to assess the associated metabolic pathways in the desert shrub Nitraria tangutorum, we conducted a transcriptome analysis of plants under control (maximum field capacity) and drought (20% of the maximum field capacity) conditions. We analyzed differentially expressed genes (DEGs) of N. tangutorum and their enrichment in the KEGG metabolic pathways database, and explored the molecular biological mechanisms underlying the answer to its drought tolerance. Between the control and drought groups, 119 classified metabolic pathways annotated 3047 DEGs in the KEGG database. For drought tolerance, nitrate reductase (NR) gene expression was downregulated, indicating that NR activity was decreased to improve drought tolerance. In ammonium assimilation, drought stress inhibited glutamine formation. Protochlorophyllide reductase (1.3.1.33) expression was upregulated to promote chlorophyll a synthesis, whereas divinyl reductase (1.3.1.75) expression was downregulated to inhibit chlorophyll-ester a synthesis. The expression of the chlorophyll synthase (2.5.1.62) gene was downregulated, which affected the synthesis of chlorophyll a and b. Overall, drought stress appeared to improve the ability to convert chlorophyll b into chlorophyll a. Our data serve as a theoretical foundation for further elucidating the growth regulatory mechanism of desert xerophytes, thereby facilitating the development and cultivation of new, drought-resistant genotypes for the purpose of improving desert ecosystems. Full article

Chlorophyllides can be found in photosynthetic organisms. Generally, chlorophyllides have a-, b-, c-, d-, and f-type derivatives, and all chlorophyllides have a tetrapyrrole structure with a Mg ion at the center and a fifth isocyclic pentanone. Chlorophyllide a can be synthesized from protochlorophyllide a, divinyl chlorophyllide a, or chlorophyll. In addition, chlorophyllide a can be transformed into chlorophyllide b, chlorophyllide d, or chlorophyllide f. Chlorophyllide c can be synthesized from protochlorophyllide a or divinyl protochlorophyllide a. Chlorophyllides have been extensively used in food, medicine, and pharmaceutical applications. Furthermore, chlorophyllides exhibit many biological activities, such as anti-growth, antimicrobial, antiviral, antipathogenic, and antiproliferative activity. The photosensitivity of chlorophyllides that is applied in mercury electrodes and sensors were discussed. This article is the first detailed review dedicated specifically to chlorophyllides. Thus, this review aims to describe the definition of chlorophyllides, biosynthetic routes of chlorophyllides, purification of chlorophyllides, and applications of chlorophyllides. Full article

A fast and high-resolution UPLC-MS^E analysis was used to identify phytoplankton pigments in an ethanol extract of Porphyridium purpureum (Pp) devoid of phycobiliproteins. In a first step, 22 standard pigments were analyzed by UPLC-MS^E to build a database including retention time and accurate masses of parent and fragment ions. Using this database, seven pigments or derivatives previously reported in Pp were unequivocally identified: β,β-carotene, chlorophyll a, zeaxanthin, chlorophyllide a, pheophorbide a, pheophytin a, and cryptoxanthin. Minor amounts of Divinyl chlorophyll a, a chemotaxonomic pigment marker for prochlorophytes, were also unequivocally identified using the database. Additional analysis of ionization and fragmentation patterns indicated the presence of ions that could correspond to hydroxylated derivatives of chlorophyll a and pheophytin a, produced during the ethanolic extraction, as well as previously described galactosyldiacylglycerols, the thylakoid coenzyme plastoquinone, and gracilamide B, a molecule previously reported in the red seaweed Gracillaria asiatica. These data point to UPLC-MS^E as an efficient technique to identify phytoplankton pigments for which standards are available, and demonstrate its major interest as a complementary method for the structural elucidation of ionizable marine molecules. Full article