Phaeosphaones: Tyrosinase Inhibitory Thiodiketopiperazines from an Endophytic Phaeosphaeria fuckelii.

Phaeosphaeria fuckelii, an endophytic fungus associated with the herbal medicine Phlomis umbrosa, produced four new thiodiketopiperazine alkaloids, phaeosphaones A-D (1-4), featuring an unusual ß-(oxy)thiotryptophan motif, along with four known analogues, phaeosphaone E (5), chetoseminudin B (6), polanrazine B (7), and leptosin D (8). Their structures were elucidated by extensive spectroscopic data analysis, and their absolute configurations were determined by single-crystal X-ray diffraction and ECD calculations. Compounds 4, 6, and 8 were found to display mushroom tyrosinase inhibitory activity with IC50 values of 33.2 ± 0.2, 31.7 ± 0.2, and 28.4 ± 0.2 µM, respectively, more potent than that of the positive control, kojic acid (IC50 = 40.4 ± 0.1 µM). A molecular-docking study disclosed the π-π stacking interaction between the indole moiety of 8 and the His243 residue of tyrosinase.

Synthesis and structure-activity relationship of theasapogenol galactosides against Magnaporthe oryzae.

Camellia oleifera is expected to provide alternative aglycone to synthesize some saponins similar to that from Schima superba with inhibitory activity against Magnaporthe oryzae. Eight theasapogenol galactosides were synthesized via protection of adjacent hydroxyl groups by a benzylidene for regioselective glycosylation in the multi-hydroxyl sapogenin. Water soluble galactose chain connected far from liposoluble end was a key group in inhibiting the growth of M. oryzea unless theasapogenol was modified by two galactosyl groups or by one galactosyl group and one benzylidene group. The amphoteric characteristics of saponin such as saccharide group number, distance between bipolar groups play an important role in inhibiting mycelium growth of M. oryzae.

A new species of Dictyochaeta (Sordariomycetes, Chaetosphaeriales, Chaetosphaeriaceae) from freshwater habitats in China.

Background: Freshwater fungi refer to the fungi that depend on the freshwater habitats for the whole life cycle or part of their life cycle. In this context, a new aquatic hyphomycete was isolated from decaying wood in a freshwater habitat in Jiangxi Province, China. New information: Dictyochaetajiangxiensis sp. nov., a new aquatic hyphomycete, is characterised by its unbranched, septate, base-fertile conidiophores with multisepta and single phialide at the apex, brown, sterile seta, monophialidic, subcylindrical conidiogenous cells narrowing below the funnel-shaped collarette, hyaline, unicellular, thin-walled, smooth, guttulate, falcate to subclavate conidia narrowly rounded at both ends with hair-like appendages. Phylogenetically, the new species Dictyochaetajiangxiensis clustered together with Dictyochaetabrevis MFLU 19-0216 in a well-supported clade, but formed a separate branch. In order to better define the taxonomic status of the new species, a phylogenetic tree of most closely-related taxa in Chaetosphaeriaceae was established, based on multi-locus sequences (ITS and LSU). The novel species is described and illustrated. Newly-generated molecular data of Dictyochaetajiangxiensis is also provided.

[Comparison of root traits of Stipa krylovii and Allium polyrhizum under grazing in typical steppe.] / æ”¾ç‰§å½±å“ä¸‹å ¸åž‹è‰åŽŸå ‹æ°é’ˆèŒ å’Œå¤šæ ¹è‘±æ ¹ç³»å±žæ€§æ¯”è¾ƒ.

Plant ecological adaptation is associated with root traits. To clarify the differences of root traits between two dominant species, Stipa krylovii and Allium polyrhizum, under different grazing intensities (light, moderate, and heavy grazing intensities), we measured root traits, including root length, root surface area, root diameter, root volume, root tips, root bifurcations, specific root length, and specific surface area. We analyzed the root morphological patterns of tip proportion, length proportion, surface proportion and volume proportion of both species, and examined their ecological adaptation strategies under grazing. The results showed that grazing inhibited aboveground and belowground growth of S. krylovii, but promoted belowground growth of A. polyrhizum. In addition, the effects of grazing on belowground part of S. krylovii was greater than aboveground part. These results indicated that the growth of S. krylovii was maintained by the aboveground part and that of A. polyrhizum was maintained by the belowground part under grazing. Root length, root bifurcations, root surface area and root tips were the main factors affecting root traits of S. krylovii, while root length, root surface area and root volume were the main factors affecting root traits of A. polyrhizum. S. krylovii could adapt to grazing stress by increasing length proportion, surface proportion and volume proportion of diameter class of 0-0.7 mm, while A. polyrhizum by increasing the length proportion, surface proportion and volume proportion of diameter class of 1.4-1.8 mm. The study on the differences of root traits between S. krylovii and A. polyrhizum could help provide a scientific basis for controlling grassland degradation.

Structures and absolute configurations of butenolide derivatives from the isopod-associated fungus Pidoplitchkoviella terricola.

In this research, twenty aromatic and branched aliphatic polyketides, including seven previously undescribed butenolide derivatives, piterriones A-G and one known analogue, along with twelve known altenusin derivatives, were isolated from the isopod-associated fungus Pidoplitchkoviella terricola. Their structures were elucidated by analysis of NMR (1D and 2D) and mass spectrometry data, and their absolute configurations were determined by Mosher's method, microscale derivatization, and comparison of their specific rotations and ECD spectra. Dihydroaltenuene B exhibited mushroom tyrosinase inhibitory activity with an IC50 value of 38.33 ± 1.59 µM, which was comparable to that of the positive control, kojic acid (IC50 = 39.72 ± 1.34 µM). A molecular-docking study disclosed the hydrogen bonding interactions between the 3-OH and 4'-OH of dihydroaltenuene B and the His244, Met280 and Gly281 residues of tyrosinase.

First record of the rare genus Typhrasa (Psathyrellaceae, Agaricales) from China with description of two new species.

Typhrasa is a rare genus that comprises two species and that has previously been reported only from Europe and North America. The present study expands the geographical scope of the genus by describing two new species - T. polycystis and T. rugocephala - from subtropical China. The new species are supported by morphological characteristics and phylogenetic analyses (ITS, LSU and tef-1α). The new species have very similar morphological characteristics and are 98% similar in their ITS region. However, T. rugocephala has two types of long gills at the same time, rarely fusiform pleurocystidia with rostrum. Detailed descriptions, colour photos, illustrations and a key to related species are presented in this paper.

Flavonoid biosynthesis controls fiber color in naturally colored cotton.

The existence of only natural brown and green cotton fibers (BCF and GCF, respectively), as well as poor fiber quality, limits the use of naturally colored cotton (Gossypium hirsutum L.). A better understanding of fiber pigment regulation is needed to surmount these obstacles. In this work, transcriptome analysis and quantitative reverse transcription PCR revealed that 13 and 9 phenylpropanoid (metabolic) pathway genes were enriched during pigment synthesis, while the differential expression of phenylpropanoid (metabolic) and flavonoid metabolic pathway genes occurred among BCF, GCF, and white cotton fibers (WCF). Silencing the chalcone flavanone isomerase gene in a BCF line resulted in three fiber phenotypes among offspring of the RNAi lines: BCF, almost WCF, and GCF. The lines with almost WCF suppressed chalcone flavanone isomerase, while the lines with GCF highly expressed the glucosyl transferase (3GT) gene. Overexpression of the Gh3GT or Arabidopsis thaliana 3GT gene in BCF lines resulted in GCF. Additionally, the phenylpropanoid and flavonoid metabolites of BCF and GCF were significantly higher than those of WCF as assessed by a metabolomics analysis. Thus, the flavonoid biosynthetic pathway controls both brown and green pigmentation processes. Like natural colored fibers, the transgenic colored fibers were weaker and shorter than WCF. This study shows the potential of flavonoid pathway modifications to alter cotton fibers' color and quality.

[Response of plant leaf traits to grazing intensity in Stipa krylovii steppe.] / å ‹æ°é’ˆèŒ è‰åŽŸæ¤ç‰©å¶ç‰‡æ€§çŠ¶å¯¹æ”¾ç‰§å¼ºåº¦çš„å“åº”.

Grazing disturbance is one of the ways to influence plant traits, and plant leaf traits actually reflect the adaptability of plants to the environment. In this study, taking Stipa krylovii steppe under different grazing intensities in Hulunbuir as research area, the relationships of leaf traits and the variation of plant traits among plant life-form functional groups was investigated. Results showed that plant traits with different life-forms had no significant difference in S. krylovii steppe. However, the relationships between plant traits were strongly correlated. The leaf phosphorus content (LPC) and the ratio of nitrogen and phosphorus (N/P) in the heavy grazing treatment had significant difference from those in the moderate grazing and the light grazing treatments. For different life-form functional groups, grazing disturbance had significant effect on LPC and N/P in the perennial forbs, indicating the perennial forbs were sensitive to grazing, and the plant nutrient utilization strategy was changed by heavy grazing. It was suggested that reasonable grazing could improve the nutrient traits of plants and restrain the degradation in S. krylovii steppe.

Paeoniflorin inhibits the maturation and immunostimulatory function of allergen-induced murine dendritic cells.

Dendritic cells (DCs) as the front lines of defense play a crucial role in allergic contact dermatitis (ACD). Paeoniflorin (PF) has been clinically proven to be effective in the treatment of inflammatory skin diseases such as ACD. However, the mechanisms underlying the anti-inflammatory effect of PF remain unclear. The aim of this study was to explore the effect of PF on the maturation and immunostimulatory function of DCs in the murine model of ACD in vitro. Murine bone marrow-derived DCs were stimulated with the contact sensitizer 1-chloro-2, 4-dinitrobenze (DNCB) in vitro. Surface antigen expression of DCs (MHC II, CD40, CD80, and CD86), as an indicator of maturation DCs and cytokines (IL-12, IFN-γ, IL-10, and TGF-ß) after DNCB stimulation in the absence or presence of PF at different doses, was detected. Then, we detected that PF-treated DCs stimulated T cells in response to DNCB. PF inhibited the up-regulation of MHC II, CD80, CD86, and CD40, decreased IL-12p70 secretion, while increased the production of IL-10 and TGF-ß, and had no effect on IFN-γ cytokine production by murine bone marrow-derived DCs in response to DNCB. DCs exposed to PF had diminished capacity to stimulate allogeneic T cell proliferation and to activate IFN-γ-producing CD4⁺ T cells and induced CD4⁺CD25⁺Foxp3⁺ T cells and IL-10-producing T cell expansion from naïve CD4⁺ T cells. These results indicate that PF may be effective in preventing and treating ACD in vitro and other inflammatory responses possibly through inhibiting maturation of DCs and limiting their capacity to stimulate T cell responses.

NtNAC-R1, a novel NAC transcription factor gene in tobacco roots, responds to mechanical damage of shoot meristem.

Topping is the important agronomic measure for flue-cured tobacco, and results in increase of the nicotine content in top leaves. Nicotine content is one of the vitals factors for the quality of tobacco leaves. Nicotine is exclusively synthesized in tobacco roots, and then transported to the leaves through the xylem. To investigate the molecular mechanism of increase in nicotine biosynthesis ability following topping, some responses of tobacco roots to topping were analyzed, and the role of NtNAC-R1 in regulating nicotine synthesis and the development of roots was discussed. The electronic cloning technique combined with RT-PCR was successfully used to clone NtNAC-R1 from tobacco roots. The number of lateral root and nicotine contents in tobacco roots increased following topping. Although spraying MeJA on leaves had no effects on the root phenotype, the nicotine contents and the expression of PMT increased markedly. The miR164 was down-regulated, and NtNAC-R1 was up-regulated in tobacco roots after topping. PMT and ODC were down-regulated in transgenic tobacco with antisense NtNAC-R1, and PMT was up-regulated in transgenic tobacco with over-expressed NtNAC-R1. In conclusion, topping can induce the decrease of miR164 and the increase of IAA content in roots, which up-regulate the expression of NtNAC-R1, resulting in the increase of lateral roots and nicotine contents. Meanwhile, topping is a mechanical wounding which can induce JA signal, and JA can enhance nicotine biosynthesis in tobacco roots. So the increase of nicotine biosynthesis ability would be related to cross-talking of JA and auxin signaling pathway after topping.

[Variation of soil physicochemical and microbial properties in degraded steppes in Hulunbeir of China].

To investigate the influence of degradation on grassland, we sampled soil and plants at three sites respectively under light, moderate and severe degradation in Hulunbeir Grassland in northern China and analyzed the differences and relationships among soil physicochemical characters, enzyme activity, soil microorganism quantity and aboveground biomass. The results showed that species richness of the moderately degraded site was highest while the aboveground biomass at the lightly degraded site was significantly higher than at the severely degraded site. Soil moisture content, nutrients (organic matter and total nitrogen) concentrations, soil microorganism quantity and enzyme activity were all decreased significantly in the degraded sites, whereas both the soil hardness and bulk density showed an opposite trend. The soil microbial biomass carbon and nitrogen contents ranged from 128 to 185 g x kg(-1) and from 5.6 to 13.6 g x kg(-1), respectively. The soil dehydrogenase and urease activities negatively correlated with soil bulk density but positively correlated with total nitrogen, organic matter, microbial biomass carbon and nitrogen. The aboveground biomass showed significantly positive correlation with the number of soil bacteria and fungi.

[Some effects of the neodymium ion on the cell wall structure of Staphyloccocus aruea].

The aim of this research is to study the effect of neodymium ion on the cell wall structure of Staphyloccocus aruea using transmission electron microscope, amino acid analyzer, infrared absorption spectrometry (IR). Experimental results show that Nd3+ can change the shape and the structure of the cell wall of Staphyloccocus aruea NdCl3 with lower concentration than the bacteriostatic concentration can help to synthesize the cell wall structure of Staphyloccocus aruea. Nd3+ with higher concentration than the bacteriostatic concentration can break the peptide bond and the hydrogen bond so as to break the net structure in the peptideoglycan cell.

[Animal experimental study of the treatment of periapical disease with recombinant human bone morphogenetic protein-2 composite].

OBJECTIVE: To investigate the effect of the treatment of periapical diseases with recombinant human netic protein (rhBMP-2) composite in dog models so as to provide basis for its clinical application. METHODS: The endotoxin-bacteria mixed fluid was injected into each root canal of the experimental teeth of dogs and the animal periapical were built. The rhBMP-2 composite was mixed by rhBMP-2, TCP, collagen and metronidazole and used in the treatment cal diseases in dog models as root apex screen. The imageology and pathology research were went on. RESULTS: The effective rate of the experimental group was remarkably higher than that of the carrier group and the control group with remarkable ference (P < 0.05). The quality of the repair of tissue was obviously better than the two other groups. CONCLUSION: The rhBMP-2 composite is a promising biological root-canal filling material.