Transposon-based identification of genes involved in the rimocidin biosynthesis in Streptomyces rimosus M527.

The transposon mutagenesis strategy has been employed to generate random insertion mutants and analyze the correlation between genes and secondary metabolites in the genus Streptomyces. In this study, our primary objective was to identify an unknown gene involved in rimocidin biosynthesis and elucidate its role in rimocidin production in Streptomyces rimosus M527. To achieve this, we established a random mutant library of S. rimosus M527 using a Tn5 transposon-mediated random mutagenesis strategy. Among the 137 isolated mutants, M527-G10 and M527-W5 exhibited the most significant variations in antagonistic activity against the plant pathogenic fungus Fusarium oxysporum f. sp. cucumerinum. Specifically, M527-G10 displayed a 72.93% reduction, while M527-W5 showed a 49.8% increase in rimocidin production compared to the wild-type (WT) strain S. rimosus M527. Subsequently, we employed a plasmid rescue strategy to identify the insertion loci of the transposon in the genomes of mutants M527-G10 and M527-W5, revealing a response regulator transcription factor (rrt) and a hypothetical protein (hyp), respectively. The roles of rrt and hyp in rimocidin biosynthesis were determined through gene deletion, overexpression in the WT strain, and complemented expression in the transposon mutants. Notably, the gene-deletion mutants M527-ΔRRT and M527-ΔHYP exhibited similar behavior in rimocidin production compared to the corresponding transposon mutants M527-G10 and M527-W5, suggesting that transposon insertions in genes rrt and hyp led to alterations in rimocidin production. Furthermore, both gene deletion and overexpression of rrt and hyp had no discernible effects on cell growth. These results reveal that genes rrt and hyp have positive and negative impacts on rimocidin production in S. rimosus M527, respectively.

[Chemical constituents from roots of Viburnum setigerum].

This experiment was to study the constituents of the roots of Viburnum setigerum through various column chromatographic techniques. Thirteen compounds were obtained and their structures were identified using chemical and spectroscopic methods as (7αH, 8'αH)-4, 4', 8α-trihydroxy-3, 3', 9-trimethoxy-7, 9'-epoxylignan (1), (7αH, 8'αH)-4, 4', 8α, 9-tetrahydroxy-3, 3'-dimethoxy-7, 9'-epoxylignan (2), alashinol G (3), alashinol F (4), (-)-secoisolariciresinol (5), (7R, 7'R, 8R, 8'S)-3, 3'-dimethoxy-7, 7'-epoxylignane -4, 4', 9, 9'-tetraol (6), (7αH, 8αH, 8'ßH)-4, 4', 7'α, 9-tetrahydroxy-3, 3'-dimethoxy-7, 9'-epoxylignan (7), loganin (8), dihydroquercetin (9), protocatechuic acid (10), 4-hydroxy-3-methoxy-benzoic acid (11), adoxoside (12), and catechin (13). Compound 1 was a new compound. Compounds 3-7 and 11 were reported from the genus Viburnum for the first time. All compounds were separated from this plant for the first time.

Preliminary results of water quality assessment using phytoplankton and physicochemical approaches in the Huai River Basin, China.

Water pollution has been a significant issue in the Huai River Basin (HRB) of China since the late 1970s. In July and December 2013, two field investigations were carried out at 10 sites along the main streams of the basin. The monitoring indices contained both physicochemical variables and the structure and composition of phytoplankton communities. The correlations between communities and physicochemical variables were analyzed using cluster analysis and redundancy analysis. Moreover, water quality was evaluated using the comprehensive nutrition state index (TLI) and Shannon-Wiener diversity index (H). Results indicated that more phytoplankton species were present in December than in July, but total density was less in December. Phytoplankton communities in the midstream of the Shaying River were affected by the same physicochemical factors throughout the year, but ammonia nitrogen and total phosphorus had the greatest influence on these sites in July and December, respectively. The water pollution status of the sampling sites was much greater in the Shaying River midstream than at other sites. TLI was more suitable than H for assessing water quality in the study area. These results provide valuable information for policy makers and stakeholders in water quality assessment, water ecosystem restoration, and sustainable basin management in the HRB.

Evaluation of hepatocyteprotective and anti-hepatitis B virus properties of Cichoric acid from Cichorium intybus leaves in cell culture.

Hepatitis B is the most common serious liver infection in the world. To date, there is still no complete cure for chronic hepatitis B. Natural caffeic acid analogues possess prominent antiviral activity, especially anti-hepatitis B virus (HBV) and anti-human immunodeficiency virus effects. Cichoric acid is a caffeic acid derivative from Cichorium intybus. In the study, the anti-hepatitis B property of cichoric acid was evaluated by the D-galactosamine (D-GalN)-induced normal human HL-7702 hepatocyte injury model, the duck hepatitis B virus (DHBV)-infected duck fetal hepatocytes and the HBV-transfected cell line HepG2.2.15 cells, respectively. The results showed that cichoric acid attenuated significantly D-GalN-induced HL-7702 hepatocyte injury at 10-100 µg/mL and produced a maximum protection rate of 56.26%. Moreover, cichoric acid at 1-100 µg/mL inhibited markedly DHBV DNA replication in infected duck fetal hepatocytes. Also, cichoric acid at 10-100 µg/mL reduced significantly the hepatitis B surface and envelope antigen levels in HepG2.2.15 cells and produced the maximum inhibition rates of 79.94% and 76.41%, respectively. Meanwhile, test compound at 50-100 µg/mL inhibited markedly HBV DNA replication. In conclusion, this study verifies the anti-hepatitis B effect of cichoric acid from Cichorium intybus leaves. In addition, cichoric acid could be used to design the antiviral agents.

Retrieving soil moisture using cosmic-ray neutron technology based on COSMIC model in the desert-oasis region.

Cosmic-ray neutron technology could estimate average soil moisture on scale of hectometers by monitoring the neutron intensity near the ground, which has been successfully applied in forest, grassland, farmland, and other ecosystems. To verify the reliability of Cosmic-ray Soil Moisture Interaction Code (COSMIC) model for retrieving mesoscale soil moisture in arid regions, we carried out soil moisture observation experiment by using the cosmic-ray neutron rover in the desert-oasis region of the middle reaches of Heihe River. The results showed that the fast neutron intensity in the desert-oasis region were 350-715 counts·(30 s)-1, and the calibrated high energy neutron intensity (Ncosmic) were (38.5±2.2) counts·(30 s)-1, which was affected by land surface characteristics. Both COSMIC model (root mean square error=0.019 g·g-1) and N0 equation (root mean square error=0.018 g·g-1) could well assess the mesoscale soil moisture, with the accuracy of soil moisture being higher considering soil lattice water. The average penetration depth was 19 cm in the oasis region and 36 cm in the desert region during the experiment. COSMIC model could be used to retrieve soil moisture by cosmic ray neutron in the desert-oasis regions, which had great potential to realize data assimilation of surface meteorological-hydrological-ecological variables by combining with land surface models.

Chromosome dynamic changes in two cultured Chinese human embryonic stem cell lines: single nucleotide polymorphism, copy number variation and loss of heterozygosity.

The quality and safety of human embryonic stem cells (hESCs) in clinical application depend on gene stability. Two Chinese hESC lines, Zh1 and Zh21, were incubated over a long period. We observed and compared the gene stability in the passage numbers 20, 17 for Zh1 cell line and passage numbers 27, 60, 68 for Zh21 cell line. Single nucleotide polymorphisis analysis indicated that hESCs in early passages had relative gene stability; and with the increase in passage number, gene instability became strong. We also found that there were copy number variations (CNVs) in both Zh21 and Zh1. We analyzed the CNVs of Chinese Han Beijing man (CHB; normal Chinese people) and found that the all CNV forms were the loss in Zh21, Zh1, and CHB. We also analyzed and compared the related pathways of the mutant genes. We propose three steps to ensure hESC safety. Firstly, besides the conventional methods such as pluripotent genes, chromosome G-banding and teratoma, high-resolution DNA chip analysis should also be adopted; secondly, chromosomal properties are monitored every 10 passages in less than passage 50 and every 5 passages in more than passage 50; thirdly, the related pathways of mutant genes should be observed because only the mutant genes with variations of their related pathways may affected cell functions.

Silencing the ADAM9 Gene through CRISPR/Cas9 Protects Mice from Alcohol-Induced Acute Liver Injury.

Alcoholic liver injury is a major global public health concern at present. The ADAM9 gene plays a crucial role in the occurrence and development of various liver diseases, but its role in acute alcoholic liver injury remains ambiguous. In this study, a chimeric single-guide RNA targeting the genomic regions of mouse ADAM9 was designed using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) technology. Next, the role of ADAM9 in acute alcoholic liver injury in vitro in cultured mouse cells and in vivo in a hydrodynamic injection-based alcoholic liver injury mouse model was documented. The findings of this study suggest that ADAM9 induces by regulating cell proliferation, apoptosis, and stress metabolism in mice. Thus, inhibiting the expression of ADAM9 gene using CRISPR/Cas9 can attenuate alcohol-induced acute liver injury in mice.

Functional traits of Fagaceae plants in shady and sunny slopes in karst degraded tiankeng.

In the negative terrain habitat of the karst degraded tiankeng, the shady and sunny slopes are dramatically different, which results in substantial variations in plant communities. With the degraded tiankeng Shenxiantang in Zhanyi, Yunnan as an example, we explored the functional traits of Fagaceae plants in the shady and sunny slopes, which would help reveal the value of tiankeng as species diversity conservation pool. The results showed that soil nutrients in the shady slope were more than those in the sunny slope. Leaf area, specific leaf area and leaf dry weight of Faga-ceae plants in the shady slope were significantly larger than those in the sunny slope. Leaf thickness was significantly lower than that in the sunny slope. Dry matter content of leaves was less than that of the sunny slope. The main environmental factors affecting functional traits of Fagaceae plants in the shady slope were soil total potassium concentration and soil moisture, while soil total phosphorus concentration was the key factor in the sunny slope. The extent of variation of leaf functional traits in shady slope was less than that in the sunny slope. Fagaceae plants mainly adapted to the shady slope habitat by changing the leaf dry weight to increase photosynthetic rate and carbon accumulation abi-lity. Sunny slope obtained more resource by keeping smaller specific leaf area and increasing the extent of variation of the leaf area. The succession rate of plant community in the shady slope of the degraded tiankeng Shenxiantang was significantly faster than that in the sunny slope. The dominance of Fagaceae plants gradually decreased in the shady slope, but remained to be the constructive species in the sunny slope.

[Vertical distribution characteristics of plant community in shady slope of degraded tiankeng talus: A case study of Zhanyi Shenxiantang in Yunnan, China]. / é€€åŒ–å¤©å‘å€’çŸ³å †é˜´å¡æ¤ç‰©ç¾¤è½åž‚ç›´åˆ†å¸ƒç‰¹å¾­­ä»¥äº‘南沾益深陷塘为例.

We investigated the characteristics of plant species diversity in tree and shurb layers and the main influencing factors in different slope positions of a shady slope of degraded tiankeng talus. The results showed that there were 21 species in 17 genera and 13 families in the tree layer, and 20 species in 20 genera and 14 families in shrub layer in the south side of the Shenxiantang. Plant communities were subtropical moist coniferous and broad-leaved mixed forest. Micro-climate led to obvious vegetation variation between the pit and the pit slope at the tiankeng. The secondary collapse over the talus with mid-slope could conserve more water, which supported the water-demanding species in a high-quality niche. All the α diversity indices including Margalef (3.58), Shannon (2.47), Simpson (0.79) and Pielou (0.86) reached the maximum at the pit bottom edge with slight variability, and the maximum coefficient of variation was only 0.226. The ß diversity index fluctuated greatly among the pit-pit, slope-pit, bottom edge. The Routledge and Whilson-Shmida indices showed the trends of decrease-increase-decrease, with the maximum values of 15.95 and 1.20, respectively. Species turnover demonstrated the upward trend overall, and the number of co-species was decreased. Plant diversity on each slope position was mainly related to the contents of total nitrogen, total phosphorus, available phosphorus and organic carbon in soil. Soil was the most important factor leading to the difference among slope positions.

Potential Drug Targets Against Hepatitis B Virus Based on Both Virus and Host Factors.

BACKGROUND: Hepatitis B is a very harmful and epidemic disease caused by hepatitis B virus (HBV). Although an effective anti-HBV vaccine is available, chronic infection poses still a huge health burden in the whole world. The present anti-HBV drugs including nucleoside analogues and interferonalpha have their limitations without exception. There is no effective drug and therapeutic method that can really and truly cure hepatitis B so far. The variability of HBV genome results in that a significant number of patients develop drug resistance during the long-term use of anti-HBV drugs. Hence, it is urgently needed to discover novel targets and develop new drugs against hepatitis B. OBJECTIVE: The review aims to provide the theory support for designing of the anti-HBV innovative drugs by offering a summary of the current situation of antiviral potential targets. RESULTS AND CONCLUSION: Since HBV is obligate intracellular parasite, and as such it depends on host cellular components and functions to replicate itself. The targeting both virus and host might be a novel therapeutic option for hepatitis B. Accordingly, we analyse the advances in the study of the potential drug targets for anti-HBV infection, focusing on targeting virus genome, on targeting host cellular functions and on targeting virus-host proteins interactions, respectively. Meanwhile, the immune targets against chronic hepatitis B are also emphasized. In short, the review provides a summary of antiviral therapeutic strategies to target virus factors, host factors and immune factors for future designing of the innovative drug against HBV infection.

[Niche characteristics of understory dominant species of talus slope in degraded tiankeng]. / 退化天坑倒石坡林下优势物种生态位特征.

We carried out niche monitoring and analysis of plant populations under the forest community in the talus slope ecotone of a typical moderate-degraded Bajiaxiantang tiankeng to provide scientific references for biodiversity conservation and vegetation restoration in degraded tiankeng area. The results showed that soil ammonium, available potassium, and available phosphorus signifi-cantly affected species distribution, which explained 37.4%, 32.8%, 29.3% of the total variation, respectively. With the change of talus slope of tiankeng (pit, uphill, mid-slope, downhill and pit bottom), life form of understory plants changed from evergreen and xerophytes to evergreen and hygro-mesophytes, with the niche overlap of herbs being larger than that of shrubs. Shrubs of Viburnum congestum and Campylotropis polyantha, and herbs of Arisaema erubescens and Arthraxon hispidus had wide ecological amplitude and strong resistance, which occupied the upper layer of the shrub and herb layers. Shrub Cornus oblonga and herb Geranium nepalense, Agrimonia pilosa lost the competitiveness with increasing soil alkalinity. Niche characteristics of understory dominant species in Bajiaxiantang were closely related to the canopy structure of mixed trees, ecological strategies of shrub and herb species, unique habitat of tiankeng, and the importance value of dominant species.

[Studies on the chemical constituents in herb of Hedyotis diffusa].

OBJECTIVE: To study the chemical constituents of Hedyotis diffusa. METHODS: Column chromatographic techniques were used for isolation and purification of chemical constituents of this plant and their structures were identified by spectroscopic analysis. RESULTS: Five compounds were isolated and identified as scandoside methyl ester (I), deacetylasperulosidic acid methyl ester (II), 10-dehydrogeniposide (III), 2-hydroxy-3-methylanthraquinone (IV), stigmasterol (V), respectively. CONCLUSION: Compound II as iridoids was isolated from Hedyotis diffusa for the first time, compound III as iridoids was isolated from genus Hedyotis for the first time.

[Characteristics of the preferential flow and its response to irrigation amount in oasis cropland].

Preferential flow is a physical process describing how water and solutes move aiong cer- tain pathways through soil profile. Studying the cropland preferential flow patterns and its influential factors could quantify the deep percolation, improve water and fertilizer use efficiency and reduce the risk of agrochemicals contaminating shallow groundwater in oasis cropland. The dye tracer exper- ments were carried out in field oasis cropland, using a brilliant blue FCF solution. The results showed that between ridge and furrow, the number of stained paths densities differed significantly at the 7.3-16.7 cm depth of the soil profiles, while the maximum dye depth had no significant differ- ence. The main influence factors of the maximum stained depth were the irrigation amount and the ant burrows. The maximum stained depth was (43.1 ± 5.9) cm with the mean irrigation amount of 120 mm, however, the maximum stained depth was (68.3 ± 7.6) cm with the irrigation amount of 55 mm under the influence of the ant burrows. Root played an important role in preferential flow, but only the fine roots (Φ ≤ 2 mm) were significantly related to the preferential flow in oasis cropland, while the coarse roots were not. In oasis cropland, the characteristics of the preferential flow were influenced by the irrigation amount, the furrow and ridge planting, the ant burrows and the roots, and the ant burrows were an uncertain factor which affected the maximum infiltration depth of the preferential flow.

[Regulation of biochar on matrix enzyme activities and microorganisms around cucumber roots under continuous cropping].

The effects of addition of biochar on the matrix enzymes activity, microorganisms population and microbial community structure were evaluated under cucumber continuous cropping for 6 years (11 rotations). Cucumbers were grown in pots in greenhouse with 5% or 3% of medium (by mass) substituted with biochar. The control consisted of medium alone without biochar. The results showed that the activity of peroxidase was significantly improved to the level of the first rotation crop form 30 to 120 d after planting in both biochar treatments, with the effect of 5% biochar being more significant than that of 3% biochar. However, the neutral phosphatase activity was markedly reduced after biochar treatment. The addition of 5% biochar had significant regulation effect on the activities of invertase and urease from 30 to 90 d after planting, while the addition of 3% biochar had little effect. The populations of bacteria and actinomycetes were increased and the fungi population was reduced in both biochar treatments from 30 to 90 d after planting, and the effect of 5% biochar was more significant than that of 3% biochar. Meanwhile, the addition of biochar significantly increased the diversity of the bacterial community structure. In summary, biochar had obvious regulation effect on soil enzyme activity, microorganism quantity and microbial community in continuous cropping nutrition medium.

[Effects of nutrition medium on cucumber growth and soil microenvironment in greenhouse under continuous cropping].

An experiment of continuous cropping of cucumber in nutrition medium (composted with straw, rural soil and puffed chicken manure) or soil was conducted in greenhouse in order to study the effects of medium type on the cucumber growth and soil microenvironment, respectively. The results showed that the two treatments both displayed different levels of obstacles resulted from continuous cropping. In the same cropping season, the nutrient content, soil invertase and urease activities and B/F (bacteria/fungi) ratio in the nutrition medium were obviously higher but fungi quantity was lower than in the soil medium, suggesting the use of nutrition medium changed the bacterial population structure as to improve the cucumber growth and yield. Under continuous cropping, correlation analysis showed that the bacterial quantity was significantly positively related with plant height and root dry mass, and markedly significantly positive correlation exited between the aboveground dry mass and yield of cucumber. The urease activity was also significantly positively related with the cucumber yield. Compared with the soil medium, the nutrition medium could greatly improve soil microenvironment and alleviate the continuous cropping obstacle.

Taraxacum mongolicum extract exhibits a protective effect on hepatocytes and an antiviral effect against hepatitis B virus in animal and human cells.

In order to validate the antiviral effect against hepatitis B virus (HBV) of Taraxacum mongolicum (T. mongolicum), the protective effect on hepatocytes, and antiviral properties against duck hepatitis B virus (DHBV) and HBV of T. mongolicum extract (TME) were evaluated in chemically-injured neonatal rat hepatocytes, DHBV-infected duck fetal hepatocytes and HBV-transfected HepG2.2.15 cells, respectively. The results demonstrated that TME at 50-100 µg/ml improved D-galactosamine (D-GalN), thioacetamide (TAA) and tert-butyl hydroperoxide (t-BHP)-injured rat hepatocytes, and produced protection rates of 42.2, 34.6 and 43.8% at 100 µg/ml, respectively. Furthermore, TME at 1-100 µg/ml markedly inhibited DHBV DNA replication. Additionally, TME at 25-100 µg/ml reduced HBsAg and HBeAg levels and produced inhibition rates of 91.39 and 91.72% at 100 µg/ml, respectively. TME markedly inhibited HBV DNA replication at 25-100 µg/ml. The results demonstrate the potent antiviral effect of T. mongolicum against HBV effect. The protective of TME effect on hepatocytes may be achieved by its ability to ameliorate oxidative stress. The antiviral properties of TME may contribute to blocking protein synthesis steps and DNA replication. Furthermore, major components of TME were quantificationally analyzed. These data provide scientific evidence supporting the traditional use of TME in the treatment of hepatitis.

[Analysis of the chemical constituents of Hedyotis diffusa].

OBJECTIVE: To analyze the chemical constituents of Hedyotis diffusa. METHODS: Column chromatographies were used to isolate and purify the chemical constituents of this plant, and their structures were identified by spectral analysis and physicochemical properties. RESULTS AND CONCLUSION: Seven compounds were isolated and identified as p-coumaric acid (I), methyl-p-coumarate (II), 2-formyl-5- hydroxymethylfuran (III), quercetin (IV), kaempferol (V), beta-sitosterol(VI) and daucosterol(VII), respectively, among which the compounds II and III were isolated from Hedyotis diffusa for the first time.