Deep insights into biodegradability mechanism and growth cycle adaptability of polylactic acid/hyperbranched cellulose nanocrystal composite mulch.

The widespread use of petroleum-based plastic mulch in agriculture has accelerated white and microplastic pollution while posing a severe agroecological challenge due to its difficulty in decomposing in the natural environment. However, endowing mulch film with degradability and growth cycle adaptation remains elusive due to the inherent non-degradability of petroleum-based plastics severely hindering its applications. This work reports polylactic acids hyperbranched composite mulch (PCP) and measured biodegradation behavior under burial soil, seawater, and ultraviolet (UV) aging to understand the biodegradation kinetics and to increase their sustainability in the agriculture field. Due to high interfacial interactions between polymer and nanofiler, the resultant PCP mulch significantly enhances crystallization ability, hydrophilicity, and mechanical properties. PCP mulch can be scalable-manufactured to exhibit modulated degradation performance under varying degradation conditions and periods while concurrently enhancing crop growth (wheat). Thus, such mulch with excellent performance can reduce labor costs and the environmental impact of waste mulch disposal to replace traditional mulch for sustainable agricultural production.

Transcriptome Analysis of Stephania tetrandra and Characterization of Norcoclaurine-6-O-Methyltransferase Involved in Benzylisoquinoline Alkaloid Biosynthesis.

Stephania tetrandra (S. Moore) is a source of traditional Chinese medicine that is widely used to treat rheumatism, rheumatoid arthritis, edema, and hypertension. Benzylisoquinoline alkaloids (BIAs) are the main bioactive compounds. However, the current understanding of the biosynthesis of BIAs in S. tetrandra is poor. Metabolite and transcriptomic analyses of the stem, leaf, xylem, and epidermis of S. tetrandra were performed to identify candidate genes associated with BIAs biosynthesis. According to the metabolite analysis, the majority of the BIAs accumulated in the root, especially in the epidermis. Transcriptome sequencing revealed a total of 113,338 unigenes that were generated by de novo assembly. Among them, 79,638 unigenes were successfully annotated, and 42 candidate structural genes associated with 15 steps of BIA biosynthesis identified. Additionally, a new (S)-norcoclaurine-6-O-methyltransferase (6OMT) gene was identified in S. tetrandra, named St6OMT2. Recombinant St6OMT2 catalyzed (S)-norcoclaurine methylation to form (S)-coclaurine in vitro. Maximum activity of St6OMT2 was determined at 30°C and pH 6.0 in NaAc-HAc buffer. Its half-life at 50°C was 22 min with the Km and kcat of 28.2 µM and 1.5 s-1, respectively. Our results provide crucial transcriptome information for S. tetrandra, shedding light on the understanding of BIAs biosynthesis and further gene functional characterization.

Glutamine Synthetases Play a Vital Role in High Accumulation of Theanine in Tender Shoots of Albino Tea Germplasm "Huabai 1".

Theanine (N-ethyl-γ-l-glutamine) is a special nonprotein amino acid that contributes to the umami taste and health function of tea. Although recent studies on tea breeding have focused on albino tea because of its umami taste, a factor of higher theanine concentration, the mechanism of biosynthesis of l-theanine is still unclear. In this study, four glutamine synthetase genes (CsGSs) were obtained and functionally characterized by overexpressing them in Arabidopsis. The enzyme activities of the purified CsGS proteins from Escherichia coli were detected. The results showed that CsGSs have a dual function in the synthesis of glutamine and theanine in vivo and in vitro. Interestingly, l-theanine was abundantly synthesized in the tender shoots of "Huabai 1". In the white tender shoots, the cytosol CsGS1.2 might exhibit increased expression to compensate for decreasing levels of chloroplast CsGS2, which plays a vital role in high accumulation of theanine in "Huabai 1". In addition, CsGS2 was most likely the key l-theanine synthases in green tissues of tea. The present findings will provide basis for and considerably broaden the scope of understanding the function of CsGSs and the mechanism of l-theanine accumulation in the tender shoots of "Huabai 1", and will be useful for breeding and screening tea with high l-theanine content.

[Effects of Coriaria Sinica Maxim's extract on microcirculation and oxidative stress of wounds in rats with deep second-degree burn].

OBJECTIVE: To investigate the effects of Coriaria Sinica Maxim's extract(CSME) on microcirculation and oxidative stress of wounds in rats with deep second-degree burn. METHODS: One hundred and eighty rats were randomly divided into normal saline group(NS), white petroleum group(WPL), silver sulfadiazine group (SSD), Coriariasinica Maxim's extract group which were divided into low dose(CSME-L),middle dose(CSME-M) and high dose(CSME-H). After anesthesia with burn instrument to burn the hair removal area of rats, these wounds were confirmed by pathological results with deep second degree burns.And then,those drugs were applied respectively on the wounds,such as NS、WPL、SSD and different concentrations of CSME. After injury at 48 h, 7 d, 14 d and 21 d,the healing rate(HR) of wound was measured, and the microvessel density (MVD), tissue moisture (TM), vascular endothelial growth factor (VEGF), model driven architecture (MDA), superoxide dismutase(SOD) and hydroxyproline(HYP) were detected, too. All pathological sections of the wound tissue were observed. RESULTS: The HR of CSME groups were obviously increased with a dose-dependent manner, which was significantly higher than that of NS and WPL (P<0.05); On the 21st day, the diameter, number, distribution of the vessels and and the TM were less than other groups with a dose-dependent manner; On the 7th and 14th day after injury, CSME groups were significantly higher than the NS, WPL and SSD with a dose-dependent manner (P<0.05), but, on the 21st day after injury, they were lower than NS, WPL and SSD with a dose-dependent (P<0.05) manner. The levels of SOD, HYP, NO and ET in CSME groups were higher than those in other groups with dose-dependent on SOD activity, HYP, NO and ET content (P<0.05), while MDA activity was weaker than other groups (P<0.05). Similarly, pathological findings were also shown that CSME groups were better than other groups with a dose-dependent manner in decrease decreasing of wound repair time and hyperplasia of scar tissue. CONCLUSIONS: CSME can relieve tissue edema, promote wound contraction, speed up the formation of eschar and accelerate the proliferation of granulation tissue, which are beneficial to the wound healing in the early stages. But, it can inhibit the hyperplasia of granulation tissue to prevent the excessive scar hyperplasia of burn wound in the later stages. Its mechanism is related to regulation what microcirculation, oxidativestress, NO and VEGF.

Protective effects of dihydroquercetin on an APAP-induced acute liver injury mouse model.

Dihydroquercetin (DHQ) is a flavonoid in the Chinese traditional herbal medicine Ramulus Euonymi, which has anti-inflammatory, antioxidant and anticancer bioactivity. In the present study, we investigated the protective effects of DHQ on acetaminophen (APAP)-induced liver injury in a mouse model for the first time. The mice received an intraperitoneal dose of APAP for model establishment. After 1 h, they were treated with DHQ at various concentrations. After 48 h of treatment, the mice were sacrificed to determine serum ALT and AST levels and the liver index, examine histopathological changes in the liver through H&E and TUNEL staining, and evaluate TNF-α and IL-6 levels using an ELISA. We also evaluated TNF-α, IL-6, Nrf2 and SOD2 mRNA expression by RT-PCR and Bcl-2, Bax and Pro-caspase-3 expression by Western blot. DHQ treatment significantly attenuated serum ALT and AST levels as well as rescued hepatomegaly. It also down-regulated TNF-α and IL-6, increased Nrf2 and SOD2 mRNA expression, down-regulated Bax, overexpressed Bcl-2 and Pro-caspase-3. Our datas suggest that DHQ treatment can effectively attenuate APAP-induced liver injury by down-regulating inflammatory factors, improving antioxidant capacity and inhibiting hepatocyte apoptosis. DHQ could be a beneficial hepatoprotective agent for the prevention and amelioration of APAP-induced acute liver injury.

Characterization of flavonoids from Dryopteris erythrosora and evaluation of their antioxidant, anticancer and acetylcholinesterase inhibition activities.

The profiles and bioactivities of flavonoids extracted from Dryopteris erythrosora were investigated. The total flavonoid content in full plant of D. Erythrosora is about 14.33%. The main flavonoids in D. Erythrosora were identified as gliricidin 7-O-hexoside, apigenin7-O-glucoside, quercetin 7-O-rutinoside, quercetin 7-O-galactoside, keampferol 7-O-gentiobioside, keampferol-3-O-rutinoside, myricetin 3-O-rhamnoside and quercitrin by means of HPLC-DAD-ESI-MS. Flavonoids (0.36mg/ml) extract from D. erythrosora showed similar 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH()), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS()), superoxide anion scavenging potential and ferric reducing antioxidant potential (FRAP) with that of rutin (0.80mg/ml). However, the antioxidant power by FRAP assay of 0.36mg/ml flavonoids extract from D. erythrosora was much weaker than that of 0.80mg/ml rutin. Moreover, the flavonoids extract from D. erythrosora showed obvious cytotoxic effects on A549 cells. The antioxidant activities of flavonoids extracts from 69 ferns showed a significant reciprocal proportion to the total flavonoids contents. The flavonoids extract from D. erythrosora exhibited a dose-dependent inhibition against acetylcholinesterase. Moreover, the anticancer activity slightly increased with improving antioxidant potential of fern flavonoids. Fern flavonoids are excellent function foods.