Isolation of rhizosheath and analysis of microbial community structure around roots of Stipa grandis.

Root zone microbial structure is particularly complex in plants with rhizosheaths, and greater understanding of the rhizosheath may play an important role in the future development of sustainable agricultural practices. However, one important reason to focus study on rhizosheath microbial structure is that there is no definite method for rhizosheath separation. The aim of this study was to explore rhizosheath isolation methods and the diversity characteristics of microorganisms around the rhizosphere. In this study, we isolated the rhizosheath of Stipa grandis, a dominant species in desert steppe, and the microorganisms in the roots, root epidermis, rhizosheath and rhizosphere soil were extracted and sequenced by 16S rRNA and ITS. The alpha diversity index of bacteria in Stipa grandis rhizosphere soil was the greatest, followed by rhizosheath, and the alpha diversity index of endophytic bacteria in root system was the smallest. The alpha diversity index of fungi in the rhizosheath and rhizosphere soil were significantly higher than that in the root epidermis and root system. There were significant differences in bacterial community structure between the root epidermis, endophytic bacteria, rhizosheath and rhizosphere soil. Unlike bacterial community structure, the community structure of fungi in the root epidermis was similar that of endophytic fungi, but significantly different from those in rhizosheath and rhizosphere soil. This study demonstrated a feasible method for separating plant rhizosheath and root epidermis. We suggest that the root epidermis can act as the interface between the host plant root and the external soil environment. We will have to re-examine the biological and ecological significance of rhizosheath and microorganisms in rhizosheath, as well as the mechanism explaining the close relationship of the rhizosheath and the plant root epidermis. This study provides theoretical and technical guidance for the isolation of the plant rhizosheath and the study of microorganisms in plant rhizosheath.

Microbial Oligosaccharides with Biomedical Applications.

Microbial oligosaccharides have been regarded as one of the most appealing natural products attributable to their potent and selective bioactivities, such as antimicrobial activity, inhibition of α-glucosidases and lipase, interference of cellular recognition and signal transduction, and disruption of cell wall biosynthesis. Accordingly, a handful of bioactive oligosaccharides have been developed for the treatment of bacterial infections and type II diabetes mellitus. Given that naturally occurring oligosaccharides have increasingly gained recognition in recent years, a comprehensive review is needed. The current review highlights the chemical structures, biological activities and divergent biosynthetic origins of three subgroups of oligomers including the acarviosine-containing oligosaccharides, saccharomicins, and orthosomycins.

Acylated Aminooligosaccharides from the Yellow Sea Streptomyces sp. HO1518 as Both α-Glucosidase and Lipase Inhibitors.

Three new acylated aminooligosaccharide (1-3), along with five known congeners (4-8), were isolated from the marine-derived Streptomyces sp. HO1518. Their structures were fully elucidated by extensive spectroscopic analysis, mainly based on 1D-selective and 2D TOCSY, HSQC-TOCSY, and HRESIMS spectrometry measurements, and by chemical transformations. All of the compounds were evaluated for their α-glucosidase and pancreatic lipase inhibitory activities. Among the isolates, D6-O-isobutyryl-acarviostatin II03 (3) and D6-O-acetyl-acarviostatin II03 (8), sharing acarviostatin II03-type structure, showed the most potent α-glucosidase and lipase inhibitory effects, far stronger than the antidiabetic acarbose towards α-glucosidase and almost equal to the anti-obesity orlistat towards lipase in vitro. This is the first report on inhibitory activities against the two major digestive enzymes for acylated aminooligosaccharides. The results from our investigation highlight the potential of acylated aminooligosaccharides for the future development of multi-target anti-diabetic drug.

A new brominated polyacetylene from Chinese marine sponge Xestospongia testudinaria.

A new brominated polyacetylene xestonariene J (1), bearing a rare 2,4-dibromo-1-ene-3-yne terminal in the molecule, along with two known related analogues (2 and 3), was obtained from Chinese marine sponge Xestospongia testudinaria. Its structure was determined on the basis of detailed spectroscopic analysis and comparison with literature data.

Acylated Aminooligosaccharides with Inhibitory Effects against α-Amylase from Streptomyces sp. HO1518.

Five new acylated aminooligosaccharides (1⁻5), together with one known related analogue (6), were isolated from Streptomyces sp. HO1518. Their structure was identified by extensive spectroscopic analysis, including 1D and 2D NMR data and high resolution electrospray ionization mass spectrometry (HRESIMS), and by comparison with those reported in the literature. All of the new compounds showed more promising porcine pancreatic α-amylase (PPA) inhibitory activities than the clinical drug acarbose, indicating them as potential pharmaceutical drug leads toward type II diabetes.

(+)-Thalianatriene and (-)-Retigeranin B Catalyzed by Sesterterpene Synthases from Arabidopsis thaliana.

Two GFPPS linked (+)-thalianatriene (1) and (-)-retigeranin B (2) sesterterpene synthase genes were identified from the genome of Arabidopsis thaliana. 1 possesses an unprecedented 11-6-5 tricyclic ring system, while 2 contains a characteristic 5-5-5-6-5 pentacyclic ring system. Their structures were determined by extensive NMR spectroscopy, chemical derivatization, and X-ray crystallography. The variable-temp NMR measurement of 3, a diepoxy-bearing derivative of 1, enables us to completely assign the NMR signals of the two conformers as 3a (67%, UUU) and 3b (33%, UUD). A plausible biosynthesis mechanism of 1 was proposed.

Further brominated polyacetylenes with pancreatic lipase inhibitory activity from Chinese marine sponge Xestospongia testudinaria.

A new brominated polyacetylene, xestonariene I (1), along with three known related analogues (2-4), was obtained from Chinese marine sponge Xestospongia testudinaria. Its structure was determined on the basis of detailed spectroscopic analysis and by comparison with literature data. Compound 4 exhibited significant inhibitory activity against pancreatic lipase, which plays a key role in preventing obesity, with an IC50 value of 0.61 µM, being comparable to that of the positive control orlistat (IC50 = 0.78 µM).

[Characteristics of Chemical Components in PM2.5 from the Coal Dust of Power Plants].

The ashes under dust catcher of typical power plants in Yangquan was collected and the contents of elements, irons, EC (elemental carbon) and OC (organic carbon) were measured in PM2. The characteristics of its chemical composition was studied and the degree of similarity of coal dust's source profiles of PM2.5 between Yangquan and other cities were compared using the coefficient of divergence method. The result indicated that the main chemical components of PM2.5 from the coal dust were SO4²â»,Ca, NO3⁻, OC, EC, Al, Si, Na, Fe, Mg and Cl⁻, accounting for 57.22% of the total mass. The enrichment factor of Pb in PM2.5 of coal dust was the largest with a significant enrichment condition, reaching 10.66-15.91. The coefficient of divergence of source profiles of PM2.5 between blind coal and fault coal was 0.072, so it was believed that they must be similar. Compared with other cities, the chemical composition of coal dust in Yangquan had specificity, in particular, the content of Ca was obviously higher than those in other domestic cities.

[Chemical Compositions and Sources Apportionment of Re-suspended Dust in Jincheng].

In order to make effective plan to provide the scientific basis for prevention and control of re-suspended dust (RD), samples of particulate sources including RD and other pollution sources of Jincheng were collected. Elements, ions and carbon in particulate sources were analyzed. Enrichment factor, potential ecological risk assessment, and chemical mass balance model were used to analyze the chemical composition and the source of RD. The result indicated that the main components in RD of Jingeheng were Si, TC, Ca, OC, Al, Mg, Na, Fe, K and SO4(2-), contributing 61.14% of total mass of RD. The most abundant content of RD was crustal elements, and the ions were enriched in the fine particles. The mass fraction of OC in PM2. was higher, whereas the mass fraction of EC in PM10 was higher, indicating that secondary organic pollutants were mainly dominated in the fine particles. The dust PM2.5 and PM10 potential ecological risk indexes were extremely strong, and PM2.5 had higher ecological harm than PM10. Pb had the highest enrichment factor of 196.97 in PM2.5, which was followed by As, Cr, Ni, V, Zn and Cu, the enrichment factors of which were all greater than 10, indicating that they were apparently enriched and affected by human activities. Soil dust, construction dust, vehicle exhaust, and coal dust were the main sources of RD.

A new bioactive steroidal ketone from the South China Sea sponge Xestospongia testudinaria.

A new steroidal ketone (1), with an ergosta-22,25-diene side chain, was obtained from the South China Sea marine sponge Xestospongia testudinaria. The structure of 1 was determined on the basis of detailed spectroscopic analysis and by comparison with literature. Compound 1 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC50 value of 4.27 ± 0.55 µM, which is comparable with the positive control oleanolic acid (IC50 = 2.63 ± 0.22 µM).

Brominated polyunsaturated lipids with protein tyrosine phosphatase-1B inhibitory activity from Chinese marine sponge Xestospongia testudinaria.

A new brominated polyunsaturated lipid, methyl (E,E)-14,14-dibromo-4,6,13-tetradecatrienoate (1), along with three known related analogues (2-4), were isolated from the Et2O-soluble portion of the acetone extract of Chinese marine sponge Xestospongia testudinaria treated with diazomethane. The structure of the new compound was elucidated by detailed spectroscopic analysis and by comparison with literature data. Compound 3 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC50 value of 5.30 ± 0.61 µM, when compared to the positive control oleanolic acid (IC50 = 2.39 ± 0.26 µM).

[Review on the secondary metabolites from Xestospongia sponges and their bioactivities].

The genus Xestospongia is one of the most widespread genera of sponges, containing abundant secondary metatolites with novel structures and potent bioactivities. The main structure types of secondary metatolites found in this genus are alkaloids, quinines, terpens, steroids, lipids, polyketones, etc. These metatolites exhibit a variety of bioactivities, such as cytotoxic, antibacterial and antiviral activities. This paper reviews the progress in the chemistry and pharmacological activities of the second metabolities from sponges of Xestospongia, especially for recent five years, with the aim for further research.

9,11-Secosteroids and polyhydroxylated steroids from two South China Sea soft corals Sarcophyton trocheliophorum and Sinularia flexibilis.

A new 9,11-secosteroid, 25(26)-dehydrosarcomilasterol (1), two new polyhydroxylated steroids, 7α-hydroxy-crassarosterol A (2) and 11-acetoxy-7α-hydroxy-crassarosterol A (3), together with three known related ones (4-6), were isolated from the South China Sea soft corals Sarcophyton trocheliophorum and Sinularia flexibilis, respectively. The structures of the new steroids were elucidated on the basis of extensive spectroscopic analyses, comparison with the literature data and chemical correlation. Compound 2 exhibited a moderate protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with an IC50 value of 33.05µM. Compounds 1-3 showed weak in vitro cytotoxicities against the tumor cell lines K562 and HL-60.

Four phragmalin orthoesters from the Chinese mangrove Xylocarpus granatum.

Four new 8,9,30-phragmalin orthoesters (1-4), along with six related known compounds, namely xyloccensins O-S (5-9) and V (10), were isolated and characterized from the twigs and leaves of the Chinese mangrove Xylocarpus granatum. The structures of the new compounds were determined on the basis of extensive spectroscopic analysis and by comparison with those of related known compounds in the literature. The absolute configuration of xyloccensin Q (7) was revised as its enantiomer by X-ray diffraction analysis employing graphite monochromated Cu Kα radiation (λ=1.54178 Å) with a Flack parameter of -0.04 and was further secured by a time-dependent density functional theory electronic circular dichroism (TDDFT ECD) calculation. Consequently, the absolute configurations of xyloccensins O (5), P (6), R (8), S (9), and V (10) were all corrected as their corresponding enantiomers, respectively. Xyloccensin S (9) exhibited inhibitory activity against protein tyrosine phosphatase 1B, a potential drug target for the treatment of type II diabetes and obesity, with an IC50 value of 8.72 µg/mL.

Thunberol, a new sterol from the Chinese brown alga Sargassum thunbergii.

A new sterol, named thunberol (1), along with four known analogs, 24-ethylcholesta-4,24(28)-dien-3-one (2), stigmasta-5,28-dien-3ß-ol (3), cholesta-5,14-dien-3ß-ol (4), and cholesta-5,23-dien-3ß,25-diol (5), were isolated from the brown alga Sargassum thunbergii collected from East China Sea. The structures of these metabolites were elucidated on the basis of detailed spectroscopic analysis and by comparison with the literature data. Thunberol (1) exhibited significant inhibitory activity against protein tyrosine phosphatase 1B, a potential drug target for the treatment of Type-II diabetes and obesity, with an IC50 value of 2.24 µg/ml.

Apotirucallane protolimonoids from the Chinese mangrove Xylocarpus granatum Koenig.

A series of previously unreported compounds including seven new apotirucallane protolimonoids, xylogranatumines A-G (1-7), were isolated together with three known analogues (8-10) from the twigs and leaves of the Chinese mangrove, Xylocarpus granatum. The structures of these new compounds were elucidated by extensive spectroscopic analysis including 1D and 2D NMR and high-resolution electrospray ionization mass spectrometry (HRESIMS) and by comparison with those of related known compounds in the literature. Xylogranatumine F (6) exhibited cytotoxic activity against A549 tumor cell in vitro.