A gene encoding a basic-type pathogenesis-related protein from Nicotiana tabacum (prb-1b) was cloned, sequenced and characterized. It contains an open reading frame of 179 amino acids that is ca. 65% homologous with the acidic PR-1 class of pathogenesis-related proteins and 87% homologous with a different basic-type PR-1 gene. In the light, physiological levels of ethylene rapidly (1 h) induced basic, but not acidic-type, PR-1 transcript. Additional elicitors acting via ethylene, such as alpha-aminobutyric acid, were shown to induce basic- and acidic-type PR-1 transcript accumulation in a light-dependent manner. In contrast, xylanase, an ethylene-independent elicitor, induced transcript accumulation of basic- and acidic-type PR-1 in a light-independent manner. Dark-induced accumulation of basic PR-1 transcript occurred at night in greenhouse-grown plants and, to a greater extent, in continuously dark-treated plants. The novel dark regulation may point to additional nonpathogenesis-related roles for these genes in plant-environment interactions.
To determine the effects of vitamin C on cardiovascular risk factors, we studied dietary vitamin C enrichment in 36 healthy male students consuming a diet high in saturated fatty acids. After a 1-mo run-in period during which the subjects consumed approximately 50 mg ascorbic acid/d (low-C diet), half of the subjects were randomly assigned to receive 500 mg ascorbic acid/d for an additional 2 mo (high-C diet). Plasma ascorbic acid increased from 13.5 micromol/L with the low-C diet to 51.7 micromol/L with the high-C diet. Plasma cholesterol increased slightly with the high-C diet, but not above baseline concentrations. This increase was offset by an increase in the lag period of in vitro LDL oxidation, which correlated with plasma ascorbic acid concentrations (r = 0.735, P = 0.0012). Lipoprotein vitamin E concentrations were unchanged with the two diets. There were no effects on concentrations of fibrinogen or factor VII. The fact that ascorbic acid reduced the in vitro susceptibility of lipoproteins to oxidation provides presumptive evidence for an interaction between aqueous and lipophilic antioxidants (vitamins C and E ) in maintaining the integrity of LDL particles.
Introduction: Inflammatory bowel diseases (IBDs) include Crohn's disease, and ulcerative colitis. Cannabis sativa preparations have beneficial effects for IBD patients. However, C. sativa extracts contain hundreds of compounds. Although there is much knowledge of the activity of different cannabinoids and their receptor agonists or antagonists, the cytotoxic and anti-inflammatory activity of whole C. sativa extracts has never been characterized in detail with in vitro and ex vivo colon models.Material and Methods: The anti-inflammatory activity of C. sativa extracts was studied on three lines of epithelial cells and on colon tissue. C. sativa flowers were extracted with ethanol, enzyme-linked immunosorbent assay was used to determine the level of interleukin-8 in colon cells and tissue biopsies, chemical analysis was performed using high-performance liquid chromatography, mass spectrometry and nuclear magnetic resonance and gene expression was determined by quantitative real-time PCR.Results: The anti-inflammatory activity of Cannabis extracts derives from D9-tetrahydrocannabinolic acid (THCA) present in fraction 7 (F7) of the extract. However, all fractions of C. sativa at a certain combination of concentrations have a significant increased cytotoxic activity. GPR55 receptor antagonist significantly reduces the anti-inflammatory activity of F7, whereas cannabinoid type 2 receptor antagonist significantly increases HCT116 cell proliferation. Also, cannabidiol (CBD) shows dose dependent cytotoxic activity, whereas anti-inflammatory activity was found only for the low concentration of CBD, and in a bell-shaped rather than dose-dependent manner. Activity of the extract and active fraction was verified on colon tissues taken from IBD patients, and was shown to suppress cyclooxygenase-2 (COX2) and metalloproteinase-9 (MMP9) gene expression in both cell culture and colon tissue.Conclusions: It is suggested that the anti-inflammatory activity of Cannabis extracts on colon epithelial cells derives from a fraction of the extract that contains THCA, and is mediated, at least partially, via GPR55 receptor. The cytotoxic activity of the C. sativa extract was increased by combining all fractions at a certain combination of concentrations and was partially affected by CB2 receptor antagonist that increased cell proliferation. It is suggested that in a nonpsychoactive treatment for IBD, THCA should be used rather than CBD.
R. 1987. Invertase and sucrose synthase activity, carbohydrate status and endogenous iAA levels during Citrus leaf development. -Physioi. Plantarum 69: 151-155.Levels of activity of the sucrose catabolizing enzymes, acid invertase (EC 3.2.1.26) and sucrose synthase (EC 2.4.1.13), were measured during development of new leaves of Citrus sinensis (L.) Osbeck cv. Shamouti. Soluble acid invertase showed a peak activity of 32 nkat (g fresh weight) ' at ca 60% of full leaf expansion and rapidly declined toward and after full expansion. There was no concomitant increase in an insoluble form of the enzyme. Sucrose synthase activity, measured in the synthesis direction, declined from 33% of full leaf expansion [10 nkat (g fresh weight)"'] to, and following, full expansion Highest sucrose synthase activity, measured in the cleavage direction, was 6 nkat (g fresh weight) ' and showed little change during development. Add invertase has a K^ of 5 mM for sucrose, while sucrose synthase had a K^ of 118 mM for sucrose. Changes in add invertase activity correlated with changes in the reducing sugar:sucrose ratio. These results suggest that soluble acid invertase activity is the primary enzyme responsible for sucrose catabolism in the expanding Citrus leaf. Changes in leaf expansion rate and invertase activity did not correlate positively with changes in endogenous free IAA level, as determined by etizyme linked immunoassay.Additional key words -Sink activity, sucrose metabolism.
The anatomy and morphology of bud regeneration were investigated in melon (Cucumis melo L.) cv. Galia, which regenerates in vitro only by direct organogenesis from the cotyledon explant. Explants were cut from the cotyledon proximal to the apex from 3-d-old in vitro seedlings, After 3 d on Murashige and Skoog medium with N6-benzyladenine, cell division can be observed in the epidermal layer on the adaxial side in the center of the explant, near the most proximal (wounded) cut edge. Over the next week, the area of the meristem increases laterally. Additional cell layers are added to the meristematic area by cell division in the epidermis. In places the epidermis remains active in cell division. Alongside those active areas there are zones where the epidermis has become inactive, although the subepidermal layers continue to divide. In transverse section, the explant now has small protuberances on the adaxial surface. After 10 d on cytokinin-containing medium, the first signs of development are visible on the adaxial surface adjacent to the proximal cut edge. The protuberances observed after 10 d are neither primordia nor buds, although some meristematic bulges are observed. The first regenerated shoot buds are observed histologically after 15 d, by which time the surface has many protuberances and some small leaves. The first shoot is found by histology after 22 d. By this time the surface is covered with protrusions and leaves, mostly without accompanying buds. The leaves may be produced from the protrusions initially visible after 10 d.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.