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Apurinic/apyrimidinic endonuclease 1 (APE1) exonuclease plays a vital proofreading role in the base excision repair pathway by removing 3’end group, including oxidatively damaged DNA bases, chain terminating nucleotide analog drugs, terminal blocking groups and mismatched bases. Herein, a simple and real time fluorometric method was developed for detecting APE1 exonuclease activity using molecular beacon as substrate. Experimental results demonstrated that the detection limit of this method was 0.01 U/μL for APE1, and the Km value was (0.27 ± 0.10) μmol/L. Moreover, the method was used to screen antibiotics and the results showed that streptomycin sulfate and gentamycin sulfate had a significant inhibitory effect on APE1 exonuclease activity in a concentration-dependent manner. Meanwhile, the assay was used for investigating the inhibitory effects of heavy metal ions on APE1 exonuclease activity. Finally, the method was further used to monitor the effect of heavy metal ions treatment of the APE1 exonuclease activity of ramie, and the results indicated that APE1 exonuclease activity was inhibited in a concentration-dependent manner after treatment with Pb2+ and Cd2+, which was consistent with heavy metal ions assay in vitro. In summary, this method provided an alternative tool for the biochemical analysis for APE1 exonuclease activity, which was hopeful for the assessment for heavy metal ions adsorption according to the enzymatic activity change in phytoremediation.

Background The bast fiber crop ramie can be used as high-quality forage resources, especially in tropical or subtropical region where there is lack of high-quality protein feed. Hongxuan No.1 (HX_1) is a unique ramie variety with a light reddish brown leaf color, which is obviously different from elite cultivar, Zhongzhu No.1 (ZZ_1, green leaf). While, the regulatory mechanism of color difference or secondary metaboliates synthesis between these two varieties have not been studied. Results In this study, phenotypic, transcriptomic and metabolomic analysis of HX_1 and ZZ_1 were conducted to elucidate the mechanism of leaf color formation. Chromaticity value and pigment content measuring showed that anthocyanin was the main metabolites imparting the different leaf color phenotype between the two varieties. Based on LC/MS, at least 14 anthocyanins were identified in leaves of HX_1 and ZZ_1, and the HX_1 showed the higher relative content of malvidin-, pelargonidin-,and cyanidin-based anthocyanins. Transcriptome and metabolome co-analysis revealed that the up-regulated expression of flavonoids synthesis gene was positively correlated with total anthocyanins accumulation in ramie leaf, and the differentfially expression of “blue gene” (F3’5’H) and the “red gene” (F3’H) in leaves bring out HX_1 metabolic flow more input into the cyanidin branch. Furthermore, the enrichment of glycosylated modification pathway (UGT and AT) and the expression of flavonoid 3-O-glucosyl transferase (UFGT), anthocyanidin reductase (ANR), in leaves were significantly influenced the diversity of anthocyanins between HX_1 and ZZ_1. Conclusions Phenotypic, transcriptomic and metabolomic analysis of HX_1 and ZZ_1 indicated that the expression levels of genes related to anthocyanin metabolism contribute to the color formation of ramie variety. Anthocyanins are important plant secandary metabilates with many physiological functions, the results of this study will deepened our understanding of ramie leaf color formation, and provided basis for molecular breeding of functional forage ramie.

Ramie (Boehmeria nivea) is a perennial herb that is highly tolerant of heavy metals. In the present study, we cloned a novel metallothionein-like gene from ramie; this gene, termed BnMTL, encodes a putative 46 amino acid protein with a molecular mass of 4.38 kDa. Analysis using quantitative RT-PCR revealed that cadmium (Cd2+ ) treatment results in elevated expression of BnMTL in the roots. We heterologously overexpressed BnMTL in Escherichia coli cells to examine its binding to Cd2+ and its possible role in homeostasis. Recombinant E. coli cells expressing BnMTL exhibited a high tolerance of Cd2+ stress up to a concentration of 1 mm, and the observed accumulation of Cd2+ was almost eight-fold higher than the control. These results demonstrate that BnMTL (i) is highly expressed in the root following exposure to Cd2+ and (ii) encodes a typical metallothionein-like protein with high cadmium-binding activity.

Al2O3/cerium oxide composite films were prepared on the surface of aluminum by an anodic oxidation and chemical conversion method. The aluminum was firstly anodized in sulfuric acid, and then the anodized aluminum was treated with the Ce(NO3)3 solution. The effect of different concentrations of 1H-Benzotriazole (BTA) on the corrosion resistance of Al2O3/cerium oxide composite films was investigated. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) with energy dispersive spectrometer (EDS), and electrochemical workstation were used to characterize the properties of the composite films. The results show that the deposition effect of cerium ions is optimal in 0.5 g/L BTA. At the same time, the surface uniformity and smoothness of the composite films are both enhanced. And the corrosion resistance of the composite film is strengthened.

Abscisic acid (ABA) is known as an important hormone regulating plant stress resistance, such as salt, drought and heavy metal resistance. However, the relationship between ABA and cadmium (Cd) enrichment in ramie (Boehmeria nivea L.) is still unclear to date. This study aimed to reveal the effect of ABA on Cd enrichment in ramie, and we received the following results: (1) Under Cd treatment, the Cd uptake of ramie increased with the increase of Cd concentration, but the chlorophyll content decreased. Under Cd treatment, the ABA content was highest in roots of ramie, followed by that in old leaves, and lowest in new leaves. Long-time treatment of high Cd concentration reduced the ability of endogenous ABA biosynthesis. (2) Spraying ABA on ramie plants (SORP) and adding ABA directly to the culture solution (ADCS) with low concentration can promote the growth of ramie and increase the amount of Cd uptake, and the effect of SORP is better. (3) The molecular reason for the decrease of chlorophyll content due to Cd stress, may be resulted from the down-regulated expression of the chlorophyll synthesis genes (BnPAO and BnNYC1) and the up-regulated expression of the chlorophyll degradation genes (BnCHLH, BnCHLG, BnHAP3A and BnPPR1). The elevated ABA content in ramie plants may due to the up-regulated expression of the ABA synthesis related genes (BnABA1, BnNCED3, and BnNCED5) and the genes (BnABCG40, BnNFXL2, BnPYL9, BnGCR2, BnGTG1, BnBGLU1, BnUTG1, BnVHAG1 and BnABI5) that encoding ABA transport and response proteins, which was consistent with the enhance the Cd uptake in ramie. Our study revealed the relationship between ABA and Cd uptake in ramie, which provided a reference for improving the enrichment of Cd in ramie.

Background: The occurrence of adventitious roots is necessary for the survival of cuttings. In this study, comparative transcriptome analysis between two ramie (Boehmeria nivea L.) varieties with different adventitious root (AR) patterns, was performed by RNA-Seq under water culture (treatment, T) and non-water culture conditions (control, CK) to reveal the regulatory mechanism of rooting. Results: Characterization of the cuttings of two ramie cultivars, Zhongzhu No 2 (Z2) and Huazhu No 4 (H4), indicated that Z2 had high adventitious rooting rate but H4 had low rooting rate. Twelve cDNA libraries of the two varieties were constructed, and a total of 26723 genes were identified. In non-water culture condition, the number of the distinctive genes in H4 was 2.7 times of that in Z2, while in water culture condition, the number of the distinctive genes in Z2 was nearly 2 times of that in H4. A total of 4411 and 5195 DEGs were identified in the comparison of H4CK vs. H4T and Z2CK vs. Z2T, respectively. After water culture, more DEGs were up-regulated in Z2, but more DEGs were down-regulated in H4. Gene Ontology (GO) Gene functional analysis of the DEGs indicated that polysaccharide metabolic process, carbohydrate metabolic process, cellular carbohydrate metabolic process, cell wall macromolecule metabolic process, and photosystem GO terms were distinctive significantly enriched in H4. Simultaneously, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that photosynthesis, photosynthesis-antenna proteins and starch and sucrose metabolism pathways were identified in H4. Moreover, KEGG analysis showed that jasmonic acid (JA) can interact with ethylene to regulate the occurrence and number of AR in Z2.Conclusions:This study reveals the transcriptomic divergence of two ramie varieties with high and low adventitious rooting rates, and provides insights into the molecular regulatory mechanism of adventitious root formation in ramie.

Flavonoids contained in ramie (Boehmeria nivea) root are important resources for officinal use. The plant seedling can grow optimally and develop an easy-harvesting adventitious root system in a hydroponic system. This research was carried out to unravel the regulation mechanism of flavonoid biosynthesis under hydroponic culturing condition, which hitherto remained unknown. Root samples of the ramie plants grown in soil and hydroponic conditions at different developmental stages were collected and pooled for transcriptome sequencing, and the expression levels of flavonoid biosynthesis-related genes and total flavonoid content were quantified. A total of 43,541 unigenes were finally annotated and the expression of 9 key unigenes were confirmed by qRT-PCR. The flavonoid biosynthesis-related gene BnF3H was significantly up-regulated in the roots of hydroponic ramie, and higher total flavonoids content in the hydroponic ramie roots was also observed. The large dataset of transcripts and unigenes provided abundant genetic information for identifying flavonoid biosynthesis genes in ramie roots. Our results suggest flavonoid biosynthesis in ramie roots is positively affected in aquatic environment, and hydroponic culturing could have a potential for enhancing total flavonoids content in ramie roots.

Apocynum plants, especially A. venetum and A. hendersonii, are rich in flavonoids. In the present study, a whole genome survey of the two species was initially carried out to optimize the flavonoid biosynthesis-correlated gene mining. Then, the metabolome and transcriptome analyses were combined to elucidate the flavonoid biosynthesis pathways. Both species have small genome sizes of 232.80 Mb (A. venetum) and 233.74 Mb (A. hendersonii) and showed similar metabolite profiles with flavonols being the main differentiated flavonoids between the two specie. Positive correlation of gene expression levels (flavonone-3 hydroxylase, anthocyanidin reductase, and flavonoid 3-O-glucosyltransferase) and total flavonoid content were observed. The contents of quercitrin, hyperoside, and total anthocyanin in A. venetum were found to be much higher than in A. hendersonii, and such was thought to be the reason for the morphological difference in color of A. venetum and A. hendersonii. This study provides valuable genomic and metabolome information for understanding of A. venetum and A. hendersonii, and lays a foundation for elucidating Apocynum genus plant flavonoid biosynthesis.

In the current study, the active flavonoids from Apocynum venetum and Apocynum hendersonii leaf were efficiently characterized using UPLC-ESI-MS/MS, and yielding the highest content of 15.35 mg/g (A. venetum) and 13.28 mg/g (A. hendersonii) respectively. The antioxidant assay in vitro showed that the isolated flavonoid ingredient groups exhibited free radical scavenging activities to DPPH, ABTS and linoleic acid. The antimicrobial assay revealed the isolated flavonoid ingredient from both A. venetum and A. hendorsonii have exerted anti-MRSA and anti-P. aeruginosa effect through disrupting cell integrity and declining ATP. In vivo assay demonstrated that these flavonoid ingredients effectively accelerated MRSA-infected and P. aeruginosa-infected Balb/c mice wound healing. In summary, these results showed that the characterized flavonoid ingredients exhibited great potential as natural antioxidant and antimicrobial agents, and shed light into future potential applications of Apocynum spp.

Xylose utilization is one of the key issues in lignocellulose bioconversion. Because of glucose repression, in most engineered yeast with heterogeneous xylose metabolic pathway, xylose is not consumed until glucose is completely utilized. Although simultaneous glucose and xylose utilization have been achieved in yeast by RPE1 deletion, we regulated ZWF1 and PGI1 transcription to improve simultaneous xylose and glucose utilization by controlling the metabolic flux from glucose into the PP pathway. Xylose and glucose consumption increased by approximately 80 and 72%, respectively, whereas ZWF1 was overexpressed by multi-copy plasmids with a strong transcriptional promoter. PGI1 expression was knocked down by promoter replacement; the glucose and xylose metabolism increased when PGI1p was replaced by weak promoters, SSA1p and PDA1p. ZWF1 overexpression decreased while PGI1 down-regulation increased the ethanol yield to some extent in the recombinant strains.

By using a hydroponic culture system, the terrestrial fiber crop ramie can growth optimally in aquatic environment and enhance exponentially quantities of high quality seedlings for subsequent field cultivation. In this study, the survival rate of ramie seedling was more than 97% when cultured using the novel hydroponic method. Further physiological analysis of the hydroponic ramie to different concentration of livestock wastewater demonstrated that all of these ramies can survival in livestock wastewater, but the 4 times diluted livestock wastewater (total N: 100.9 mg L−1, total P: 2.69 mg L−1) was more appropriate for ramie growth. The nutrients N and P in livestock wastewater were significantly decreased by the growth of ramie, and the removal efficiency of total N and total P in the 4 times diluted livestock wastewater achieved 78.1% and 43.1% respectively within 5 weeks. In conclusion, our studies highlight that the combination of ramie and the hydroponic technology resulted to be effective in the phytoremediation of livestock wastewater.

This study explored the effects of long-term bathing in radon hot springs on oxidative damage and antioxidation function in humans. In this study, blood was collected from residents in the Pingshan radon hot spring area (RHSA), Jiangzha RHSA, and control area (CA). 8-Hydroxydeoxyguanosine (8-OHdG) and thioredoxin reductase (TrxR), representing oxidation and antioxidant levels, respectively, were analyzed as indices. Compared to the CA group, the RHSA group in the Pingshan and Jiangzha areas showed significantly decreased 8-OHdG levels ( Z = −3.350, −3.316, respectively, P < .05) and increased TrxR levels ( Z = 2.394, 3.773, respectively, P < .05). The RHSA and CA groups in Jiangzha had lower levels of TrxR and 8-OHdG compared to those in Pingshan. This finding may be related to the different radon concentration levels, bathing time and other factors. Results suggested that long-term bathing in radon hot spring may activate antioxidant function and reduce oxidative damage in the body.

The endoglucanase gene endo753 from Aspergillus flavus NRRL3357 strains was cloned, and the recombinant Endo753 was displayed on the cell surface of Saccharomyces cerevisiae EBY100 strain by the C-terminal fusion using Aga2p protein as anchor attachment tag. The results of indirect immunofluorescence and Western blot confirmed the expression and localization of Endo753 on the yeast cell surface. The hydrolytic activity test of the whole-cell enzyme revealed that Endo753 immobilized on the yeast cell surface had high endoglucanase activity. The functional characterization of the whole-cell enzyme was investigated, and the whole-cell enzyme displayed the maximum activity at pH 8 and 50 °C. The enzyme was stable in a pH range of 7.0–10.0. Furthermore, the whole-cell enzyme displayed high thermostability below 50 °C and moderate stability between 50 and 70 °C. These properties make endo753 a good candidate in bioethanol production from lignocellulosic materials after displaying on the yeast cell surface.

Xylose utilization is one key issue for the bioconversion of lignocelluloses. It is a promising approach to engineering heterologous pathway for xylose utilization in Saccharomyces cerevisiae. Here, we constructed a xylose-fermenting yeast SyBE001 through combinatorial fine-tuning the expression of XylA and endogenous XKS1. Additional overexpression of genes RKI1, RPE1, TKL1, and TAL1 in the non-oxidative pentose phosphate pathway (PPP) in SyBE001 increased the xylose consumption rate by 1.19-fold. By repetitive adaptation, the xylose utilization rate was further increased by ∼10-fold in the resultant strain SyBE003. Gene expression analysis identified a variety of genes with significantly changed expression in the PPP, glycolysis and the tricarboxylic acid cycle in SyBE003.

Organic geochemistry characteristics of carbonate rock and mudstone samples are reported for cores in exploration wells and outcrops in the Carboniferous and Lower Permian, Turpan-Hami Basin. Extensive analyses include organic matter abundance, kerogen type, hydrocarbon generation and thermal evolution. The mudstone is higher in organic content, ranging from 0 – 4.45% TOC, suggesting relatively good source rock potential; whereas, the carbonate rock has a maximum TOC of 0.52% and is basically non-source rock. The matrix types of both carbonate rock and mudstone are grouped into Type III (dominant) and II2 (less). The carbonate rock is a bit better quality than the mudstone in organic types. The source rock from downhole samples can be early mature to highly mature. The maturity of outcrop samples range from mature to over-mature. The lower maturity of well samples is related to the shallower depth of the samples. The higher maturity of outcrop samples may be related to the tectonic movement and high geothermal gradient. Based on characteristics of thermal evolution, more effective Carboniferous-Lower Permian source rocks are distributed in the deeper location of the sag and can generate more natural gas. The igneous/volcanic rocks are better deep reservoirs in which natural gas accumulates. Key words: Organic geochemistry, Carboniferous, Lower Permian, source rock, Turpan-Hami Basin

Functional screening of a metagenomic library of termite hindgut identified an overlapping gene cluster encoding the phosphotransferase system (PTS) components, which consisted of a glucoside specific PTS enzyme II gene (glu1923) and a glycoside hydrolase gene (glu1392). Hydrolytic experiments revealed that the combined effect of Glu1923 and Glu1392 was responsible for the utilization of glucosidic substrates in recombinant Escherichia coli (E. coli) strains. Yeast two hybrid analysis suggested that there was an interaction between Glu1923 and Glu1392, and the domain EIIA of Glu1923 played an important role for the interaction. In addition, the hydrolase Glu1392 displayed hydrolysis ability toward cellobiose and maltose, and had a very high tolerance to glucose with a Ki value of 2.25M. These properties make Glu1392 an interesting candidate in biotechnology applications after further study.