Suaeda glauca Bunge produces dimorphic seeds on the same plant, with brown seeds displaying non-dormant characteristics and black seeds exhibiting intermediate physiological dormancy traits. Previous ...studies have shown that black seeds have a very low germination rate under natural conditions, but exogenous GA 3 effectively enhanced the germination rate of black seeds. However, the physiological and molecular mechanisms underlying the effects of GA 3 on S. glauca black seeds are still unclear. In this study, transcriptomic profiles of seeds at different germination stages with and without GA 3 treatment were analyzed and compared, and the TTF, H 2 O 2 , O 2 – , starch, and soluble sugar contents of the corresponding seed samples were determined. The results indicated that exogenous GA 3 treatment significantly increased seed vigor, H 2 O 2 , and O 2 – contents but decreased starch and soluble sugar contents of S. glauca black seeds during seed dormancy release. RNA-seq results showed that a total of 1136 DEGs were identified in three comparison groups and were involved mainly in plant hormone signal transduction, diterpenoid biosynthesis, flavonoid biosynthesis, phenylpropanoid biosynthesis, and carbohydrate metabolism pathway. Among them, the DEGs related to diterpenoid biosynthesis ( SgGA3ox1 , SgKAO and SgGA2ox8 ) and ABA signal transduction ( SgPP2Cs ) could play important roles during seed dormancy release. Most genes involved in phenylpropanoid biosynthesis were activated under GA 3 treatment conditions, especially many SgPER genes encoding peroxidase. In addition, exogenous GA 3 treatment also significantly enhanced the expression of genes involved in flavonoid synthesis, which might be beneficial to seed dormancy release. In accordance with the decline in starch and soluble sugar contents, 15 genes involved in carbohydrate metabolism were significantly up-regulated during GA 3 -induced dormancy release, such as SgBAM , SgHXK2 , and SgAGLU , etc. In a word, exogenous GA 3 effectively increased the germination rate and seed vigor of S. glauca black seeds by mediating the metabolic process or signal transduction of plant hormones, phenylpropanoid and flavonoid biosynthesis, and carbohydrate metabolism processes. Our results provide novel insights into the transcriptional regulation mechanism of exogenous GA 3 on the dormancy release of S. glauca black seeds. The candidate genes identified in this study may be further studied and used to enrich our knowledge of seed dormancy and germination.
A fucan sulfate (HfFS) was isolated from the sea cucumber Holothuriafloridana after proteolysis-alkaline treatment and purified with anion-exchange chromatography. The molecular weight (Mw) of HfFS ...was determined to be 443.4 kDa, and the sulfate content of HfFS was 30.4%. The structural analysis of the peroxidative depolymerized product (dHfFS-1) showed that the primary structure of HfFS was mainly composed of a distinct pentasaccharide repeating unit -l-Fuc2S4S-α(1,3)-l-Fuc-α(1,3)-Fuc-α(1,3)-l-Fuc2S-α(1,3)-l-Fuc2S-α(1,3)-n-. Then, the “bottom-up” strategy was employed to confirm the structure of HfFS, and a series of fucooligosaccharides (disaccharides, trisaccharides, and tetrasaccharides) were purified from the mild acid-hydrolyzed HfFS. The structures identified through 1D/2D NMR spectra showed that these fucooligosaccharides could be derivates from the pentasaccharide units, while the irregular sulfate substituent also exists in the units. Anticoagulant activity assays of native HfFS and its depolymerized products (dHf-1~dHf-6) in vitro suggested that HfFS exhibits potent APTT-prolonging activity and the potencies decreased with the reduction in molecular weights, and HfFS fragments (dHf-4~dHf-6) with Mw less than 11.5 kDa showed no significant anticoagulant effect. Overall, our study enriched the knowledge about the structural diversity of FSs in different sea cucumber species and their biological activities.
Unique fucosylated glycosaminoglycans (FG) have attracted increasing attention for various bioactivities. However, the precise structures of FGs usually vary in a species-specific manner. In this ...study, HfFG was isolated from
and purified by anion exchange chromatography with the yield of ~0.9%. HfFG was composed of GlcA, GalNAc and Fuc, its molecular weight was 47.3 kDa, and the -OSO
/-COO
molar ratio was 3.756. HfFG was depolymerized by a partial deacetylation-deaminative cleavage method to obtain the low-molecular-weight HfFG (dHfFG). Three oligosaccharide fragments (Fr-1, Fr-2, Fr-3) with different molecular weights were isolated from the dHfFG, and their structures were revealed by 1D and 2D NMR spectroscopy. HfFG should be composed of repeating trisaccharide units -{(L-FucS-α1,3-)d-GlcA-β1,3-d-GalNAc
-β1,4-}-, in which sulfated fucose (FucS) includes Fuc
, Fuc
and Fuc
residues linked to O-3 of GlcA in a ratio of 45:35:20. Furthermore, the heparanase inhibitory activities of native HfFG and oligosaccharide fragments (Fr-1, Fr-2, Fr-3) were evaluated. The native HfFG and its oligosaccharides exhibited heparanase inhibitory activities, and the activities increased with the increase of molecular weight. Additionally, structural characteristics such as sulfation patterns, the terminal structure of oligosaccharides and the presence of fucosyl branches may be important factors affecting heparanase inhibiting activity.
Li-rich layered oxide cathodes have attracted extensive attention due to their high energy density. However, due to the low initial Coulombic efficiency and the capacity fading and voltage fading ...during cycling, its practical application is still a great challenge. Here, we report the one-step realization of layered/spinel heterostructures and Na doping by the sodium dodecyl sulfate (SDS)-assisted sol-gel method. The spinel phase provides 3D diffusion channels for Li-ions, and sodium doping changes the layered lattice constant and expands the layer spacing. Therefore, the designed Li1.15Mn0.54Ni0.13Co0.13Na0.05O2 (SDS-2) cathode possesses excellent electrochemical performance such as higher initial Coulombic efficiency and rate capacity and also alleviates voltage decay. The initial discharge-specific capacity of SDS-2 is 298.8 mAh g-1 at 0.1 C, and the discharge-specific capacity can reach 111.7 mAh g-1 at 10 C. This strategy can provide new insights into the design and synthesis of high-performance Li-rich layered oxide cathode materials.Li-rich layered oxide cathodes have attracted extensive attention due to their high energy density. However, due to the low initial Coulombic efficiency and the capacity fading and voltage fading during cycling, its practical application is still a great challenge. Here, we report the one-step realization of layered/spinel heterostructures and Na doping by the sodium dodecyl sulfate (SDS)-assisted sol-gel method. The spinel phase provides 3D diffusion channels for Li-ions, and sodium doping changes the layered lattice constant and expands the layer spacing. Therefore, the designed Li1.15Mn0.54Ni0.13Co0.13Na0.05O2 (SDS-2) cathode possesses excellent electrochemical performance such as higher initial Coulombic efficiency and rate capacity and also alleviates voltage decay. The initial discharge-specific capacity of SDS-2 is 298.8 mAh g-1 at 0.1 C, and the discharge-specific capacity can reach 111.7 mAh g-1 at 10 C. This strategy can provide new insights into the design and synthesis of high-performance Li-rich layered oxide cathode materials.
Peroxidative depolymerization is often used to elucidate the structure and structure-activity relationship of fucosylated glycosaminoglycan (FG), while the selectivity of bond cleavage and structural ...characteristics of the resulting fragments remain to be confirmed. Here, the FG from Stichopus variegatus (SvFG) was depolymerized by H2O2, and a series of yielded mono- and oligo-saccharides were purified. Almost all the non-reducing ends of oligosaccharides were d-GalNAc4S6S, suggesting that GlcA-β1,3-GalNAc4S6S linkage was preferentially cleaved. The model reactions showed the glycosidic bond of uronate was more susceptible than those of N-acetyl hexosamine and fucose, which should be due to bond energy of the anomeric CH. The reducing ends of oligosaccharides include C4–C6 saccharic acid and GalNAc or GalNAcA, which should be derived from the oxidation of the reducing end. A hexasaccharide with tartaric acid exhibited increased anti-iXase activity, suggesting the oxidation of reducing end did not impair the anti-iXase activity of FG-derived oligosaccharides.
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The slug Vaginulus alte is used as folk medicine in China, but the structure and activities of its galactan components remain to be clarified. Here, the galactan from V. alte (VAG) was purified. The ...Mw of VAG was determined as ~28.8 kDa. Chemical composition analysis showed that VAG was composed of d-galactose (75 %) and l-galactose (25 %). To elucidate its precise structure, a series of disaccharides and trisaccharides were purified from mild acid hydrolyzed VAG and their structures were characterized by 1D/2D NMR spectroscopy. Based on methylation analysis and structural analysis of oligosaccharides, VAG was elucidated as a highly branched polysaccharide and mainly composed of (1 → 6)- or (1 → 3)-linked β-d-galactose, and distinct (1 → 2)-linked α-l-galactose. The investigation of probiotic effects in vitro revealed that VAG could promote the growth of B. thetaiotaomicron and B. ovatus, while had no effect on the growth of L. acidophilus, L. rhamnosus, B. longum subsp. infantis and B. animalis subsp. lactis, but dVAG-3 with Mw ~1.0 kDa could promote the growth of L. acidophilus. These results will provide insights into specific structures and functions of polysaccharides from the V. alte.
•A highly branched galactan VAG was obtained from the slug Vaginulus alte.•Structures of oligosaccharides released from VAG were identified.•VAG was consisted of (1 → 3)-, (1 → 6)-linked β-d-galactose and (1 → 2)-linked α-l-galactose.•VAG could promote the growth of B. thetaiotaomicron and B. ovatus.•dVAG-3 with Mw of 1.0 kDa could promote the growth of L. acidophilus.
A fucan sulfate (HfFS) was isolated from the sea cucumber Holothuria floridana after proteolysis-alkaline treatment and purified with anion-exchange chromatography. The molecular weight (Mw) of HfFS ...was determined to be 443.4 kDa, and the sulfate content of HfFS was 30.4%. The structural analysis of the peroxidative depolymerized product (dHfFS-1) showed that the primary structure of HfFS was mainly composed of a distinct pentasaccharide repeating unit -l-Fuc2S4S-α(1,3)-l-Fuc-α(1,3)-Fuc-α(1,3)-l-Fuc2S-α(1,3)-l-Fuc2S-α(1,3)-n-. Then, the “bottom-up” strategy was employed to confirm the structure of HfFS, and a series of fucooligosaccharides (disaccharides, trisaccharides, and tetrasaccharides) were purified from the mild acid-hydrolyzed HfFS. The structures identified through 1D/2D NMR spectra showed that these fucooligosaccharides could be derivates from the pentasaccharide units, while the irregular sulfate substituent also exists in the units. Anticoagulant activity assays of native HfFS and its depolymerized products (dHf-1~dHf-6) in vitro suggested that HfFS exhibits potent APTT-prolonging activity and the potencies decreased with the reduction in molecular weights, and HfFS fragments (dHf-4~dHf-6) with Mw less than 11.5 kDa showed no significant anticoagulant effect. Overall, our study enriched the knowledge about the structural diversity of FSs in different sea cucumber species and their biological activities.
The Mn cluster （Mn4CaO5） on the thylakoid luminal side of photosystem II （PSII） catalyzes the photosynthetic oxygen-evolving reaction, an essential process for life on Earth. In higher plants and ...green algae, the Mn cluster is surrounded by the membraneextrinsic proteins PsbO （33 kDa）, PsbP （23 kDa）, and PsbQ （17 kDa） （Murata and Miyao, 1985）.
Dear Editor,
Grana thylakoids in plants comprise multiple, tightly appressed thylakoid membranes in the chloroplast, which greatly increase the area-to-volume ratio and significantly improve the ...ability of chloroplasts to capture light. Grana layers are stacked and interact through the stromal surface of proteins embedded in the grana membranes,
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