Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
Add more filters










Database
Language
Publication year range
1.
Planta ; 254(2): 22, 2021 Jul 04.
Article in English | MEDLINE | ID: mdl-34218358

ABSTRACT

MAIN CONCLUSION: The downregulation of PpPG21 and PpPG22 expression in melting-flesh peach delays fruit softening and hinders texture changes by influencing pectin solubilization and depolymerization. The polygalacturonase (PG)-catalyzed solubilization and depolymerization of pectin plays a central role in the softening and texture formation processes in peach fruit. In this study, the expression characteristics of 15 PpPG members in peach fruits belonging to the melting flesh (MF) and non-melting flesh (NMF) types were analyzed, and virus-induced gene silencing (VIGS) technology was used to identify the roles of PpPG21 (ppa006839m) and PpPG22 (ppa006857m) in peach fruit softening and texture changes. In both MF and NMF peaches, the expression of PpPG1, 10, 12, 23, and 25 was upregulated, whereas that of PpPG14, 24, 35, 38, and 39 was relatively stable or downregulated during shelf life. PpPG1 was highly expressed in NMF fruit, whereas PpPG21 and 22 were highly expressed in MF peaches. Suppressing the expression of PpPG21 and 22 by VIGS in MF peaches significantly reduced PG enzyme activity, maintained the firmness of the fruit during the late shelf life stage, and suppressed the occurrence of the "melting" stage compared with the control fruits. Moreover, the downregulation of PpPG21 and 22 expression also reduced the water-soluble pectin (WSP) content, increased the contents of ionic-soluble pectin (ISP) and covalent-soluble pectin (CSP) and affected the expression levels of ethylene synthesis- and pectin depolymerization-related genes in the late shelf life stage. These results indicate that PpPG21 and 22 play a major role in the development of the melting texture trait of peaches by depolymerizing cell wall pectin. Our results provide direct evidence showing that PG regulates peach fruit softening and texture changes.


Subject(s)
Prunus persica , Cell Wall/metabolism , Down-Regulation , Fruit/metabolism , Gene Expression Regulation, Plant , Polygalacturonase/metabolism
2.
Int J Mol Sci ; 17(11)2016 Nov 18.
Article in English | MEDLINE | ID: mdl-27869753

ABSTRACT

Polygalacturonase (PG) is an important hydrolytic enzyme involved in pectin degradation during fruit softening. However, the roles of PG family members in fruit softening remain unclear. We identified 45 PpPG genes in the peach genome which are clustered into six subclasses. PpPGs consist of four to nine exons and three to eight introns, and the exon/intron structure is basically conserved in all but subclass E. Only 16 PpPG genes were expressed in ripening fruit, and their expression profiles were analyzed during storage in two peach cultivars with different softening characteristics. Eight PGs (PpPG1, -10, -12, -13, -15, -23, -21, and -22) in fast-softening "Qian Jian Bai" (QJB) fruit and three PGs (PpPG15, -21, and -22) in slow-softening "Qin Wang" (QW) fruit exhibited softening-associated patterns; which also were affected by ethylene treatment. Our results suggest that the different softening characters in QW and QJB fruit is related to the amount of PG members. While keeping relatively lower levels during QW fruit softening, the expression of six PGs (PpPG1, -10, -12, -11, -14, and -35) rapidly induced by ethylene. PpPG24, -25 and -38 may not be involved in softening of peach fruit.


Subject(s)
Fruit/genetics , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Plant , Plant Proteins/genetics , Polygalacturonase/genetics , Prunus persica/genetics , Base Sequence , Chromosome Mapping , Chromosomes, Plant/genetics , Ethylenes/biosynthesis , Fruit/metabolism , Gene Expression Profiling/methods , Isoenzymes/classification , Isoenzymes/genetics , Isoenzymes/metabolism , Multigene Family , Phylogeny , Plant Proteins/metabolism , Polygalacturonase/classification , Polygalacturonase/metabolism , Prunus persica/classification , Prunus persica/enzymology , Reverse Transcriptase Polymerase Chain Reaction , Sequence Homology, Amino Acid , Species Specificity
3.
J Opt Soc Am A Opt Image Sci Vis ; 30(11): 2273-9, 2013 Nov 01.
Article in English | MEDLINE | ID: mdl-24322925

ABSTRACT

We study the physical mechanism of near-field interference of slit doublet and explore the distinctive phenomena in near-field interference of slit doublet. The average electric field and average energy-flow density are chosen to describe the near-field distribution rules of the electromagnetic field. The numerical calculations for near-field interference of slit doublet under different illumination conditions are performed according to the finite-difference time-domain method, and the distinctive characteristics of the near-field interference of slit doublet are provided. They include the polarization dependence, the distortion of fringes, and the bifurcation of the fringes. These characteristics are completely different from those of the far-field interference. With the aid of the interference of two slits and of slit and groove, the physical mechanism of polarization dependence of near-field interference is investigated. The fringe distortion of the electric field and the fringe bifurcation of the energy-flow density reflect the amplitude and phase variations of the electromagnetic field. The influences of the slit parameters and the base material on the near-field interference of slit doublet are also discussed. These results may provide us with new insights into the underlying physics of interaction between complex nanostructures and electromagnetic waves.

4.
Nat Prod Res ; 27(23): 2251-5, 2013.
Article in English | MEDLINE | ID: mdl-23962054

ABSTRACT

(-)-Arctigenin, an important active constituent of the traditional Chinese herb Fructus Arctii, was found to exhibit various bioactivities, so it can be used as a good lead compound for further structure modification in order to find a safer and more potent medicine. (-)-Arctigenin derivatives 1-5 of (-)-arctingen were obtained by modifying with ammonolysis at the lactone ring and sulphonylation at C (6') and C (6″) and O-demethylation at CH3O-C (3'), CH3O-C (3″) and CH3O-C (4″), and their anticancer bioactivities were examined.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Furans/pharmacology , Lignans/pharmacology , Antineoplastic Agents, Phytogenic/chemistry , Cell Line, Tumor , Drug Discovery , Furans/chemistry , Humans , Lignans/chemistry , Magnetic Resonance Spectroscopy , Mass Spectrometry , Molecular Structure
5.
Appl Opt ; 52(21): 5083-7, 2013 Jul 20.
Article in English | MEDLINE | ID: mdl-23872752

ABSTRACT

Theoretic and experimental studies of the Talbot effect of quasi-periodic gratings are performed in this paper. The diffractions of periodic and quasi-periodic square aperture arrays in Fresnel fields are analyzed according to the scalar diffraction theory. The expressions of the diffraction intensities of two types of quasi-periodic gratings are deduced. Talbot images of the quasi-periodic gratings are predicted to appear at multiple certain distances. The quasi-periodic square aperture arrays are produced with the aid of a liquid crystal light modulator, and the self-images of the quasi-periodic gratings are measured successfully in the experiment. This study indicates that even a structure in short-range disorder may take on the self-imaging effect in a Fresnel field.

SELECTION OF CITATIONS
SEARCH DETAIL
...