A new sesquiterpene from endophytic fungus Colletotrichum sp. B-89.

A new sesquiterpene, named (1S, 4aS, 7 R, 8 R, 8aR) Decahydro-1,4a-dimethyl-7-(1-methylethyl)-1,8-naphthalenediol (1), and six known compounds (2-7) were obtained from Colletotrichum sp. B-89, an endophytic fungus isolated from Dracaena cochinchinensis collected at Xishuangbanna, Yunnan. Their structures were elucidated by detailed analysis of comprehensive spectroscopic data, and the structure of 1 was further determined by X-ray diffraction analysis. The antibacterial activities of above compounds were assayed and compound 6 exhibited certain activities against S. aureus ATCC 25923, B. subtilis ATCC 6633, E. coli ATCC 25922, and K. pneumoniae ATCC 13883.

Two new diketopiperazines from the Cordyceps fungus Samsoniella sp. XY4.

Two new diketopiperazines, namely samsoniellain A (1) and samsoniellain B (2), together with two known compounds (3, 4) were isolated from Cordyceps fungus Samsoniella sp. XY4. The planar structures of 1 and 2 were determined by HRESIMS, 1D and 2D NMR spectroscopy. The absolute configurations of 1 and 2 were determined by comparison of quantum chemical TDDFT calculated and experimental ECD spectra. Results of antimicrobial activity indicated that compound 2 showed weak bacteriostatic activities against S. typhimurium χ 8956, H. influenza ATCC 10211, MRSA 2024 with the MIC values of 128, 256, and 256 µg ml-1, respectively. This is the first report about secondary metabolites of Samsoniella sp.

[Main Chemical Components in Atmospheric Precipitation and Their Sources in Xi'an].

In order to understand the current status of main chemical components of atmospheric precipitation in Xi'an, the pH, electrical conductivity, mass concentration of water-soluble ions and heavy metals, wet deposition fluxes, and their sources in precipitation samples in urban and suburban areas of Xi'an in 2019 were studied. The results showed that the pH, conductivity, water-soluble ions, and heavy metals in precipitation in Xi'an in winter were higher than those in other seasons. The main water-soluble ions in precipitation were Ca2+, NH+4, SO2-4, and NO-3, and the sum of these ions accounted for (88.5%±2.8)% of the total ion concentration in urban and suburban areas. The main heavy metals were Zn, Fe, and Zn and Mn; their sum accounted for (54.0%±3)% and (47.0%±8)% of the total metal concentration. The wet deposition fluxes of water-soluble ions in precipitation in urban and suburban areas were (253.2±58.4) mg·(m2·month)-1 and (241.9±61.1) mg·(m2·month)-1, respectively. They showed higher values in winter than those in other seasons. The wet deposition fluxes of heavy metals were (86.2±37.5) mg·(m2·month)-1 and (88.1±37.4) mg·(m2·month)-1, respectively, with little seasonal difference. The source analysis using PMF showed that the water-soluble ions in urban and suburban precipitation mainly came from combustion sources (57.5% and 32.32%), followed by motor vehicles (24.4% and 17.2%) and dust sources (18.1% and 27.0%). The ions in suburban precipitation were also affected by local agriculture (11.1%). Heavy metals in precipitation in urban and suburban areas mainly came from industrial sources (51.8% and 46.7%), and the contribution rate of coal and motor vehicle mixed sources in winter was 10.7% and 6.1% higher than that in summer, respectively.

A new δ-valerolactone produced by marine Streptomyces sp. YIM 13591.

A new δ-valerolactone compound, named 8-hydroxy invictolide 2 (1), a new natural product 4-hydroxy-3,5-dimethyl-6-(pentan-2-yl) tetrahydro-2H-pyran-2-one (2) together with four known compounds cyclo (L-Pro-L-Tyr) (3), cyclo (D-Pro-L-Tyr) (4), acetyltryptophan methyl ester (5), 2-aminobenzoic acid (6) were isolated from marine Streptomyces sp. YIM 13591. Their structures were elucidated by NMR spectroscopic data, HRESIMS and specific rotation, and the absolute configurations of the stereo centre in lactone ring 1 and 2 were further confirmed by electronic circular dichroism (ECD) calculation. The antimicrobial effects of these compounds were evaluated by the paper diffusion method.

A new 1,4-benzoxazine derivative produced by endophytic Colletotrichum gloeosporioides B-142.

Colletotrin A (1), a new 1,4-benzoxazine derivative, and eight known compounds, including two alkaloids (2-3), one acylamide (4), one benzaldehyde (5), and four sterols (6-9) were obtained from endophytic fungus Colletotrichum gloeosporioides B-142, which was isolated from Dracaena cochinchinensis. Among them, 1,2,3,4-tetrahydroquinoline-4,8-diol (2) was reported for the first time as natural product. The structure of compound 1 was elucidated with help of spectroscopic data including IR, UV, electronic circular dichroism (ECD) calculation, HRESIMS, 1D and 2D NMR (COSY, HSQC and HMBC). The antimicrobial activities were evaluated by disc diffusion method.

Microbial community composition and soil metabolism in the coexisting Cordyceps militaris and Ophiocordyceps highlandensis.

Cordyceps sensu lato is a complex fungus-larva symbiote, and its distribution is affected by the geography, climate, soil environment, and cohabitating microorganisms. However, despite the fact Cordyceps militaris and Ophiocordyceps highlandensis are different species, they coexist in the Pinus armandi forest of Dashao in Songming County, Yunnan, China. We explored the microbial compositions and soil metabolism inhabited by C. militaris and O. highlandensis using high-throughput sequencing and nontargeted metabonomics. The results indicated that the bacterial and fungal compositions in the soil microhabitat communities of C. militaris, O. highlandensis, and null Cordyceps group were similar. However, the community compositions in the fruiting bodies of C. militaris and O. highlandensis were different. The dominant phylum Ascomycota and dominant genus Cordyceps were detected in the fruiting body of C. militaris. Except for Ascomycota, the dominant phylum Chytridiomycota and dominant genera Ophiocordyceps, Unclassified_k__Hypocreales, Circinotrichum, Cladosporium, and Unclassified_k__chytridiomycetesg were detected in the fruiting body of O. highlandensis. The plant probiotic bacteria Phyllobacterium was detected in the fruiting body of C. militaris. The growth-promoting bacteria Pseudomonas was detected in the fruiting body of O. highlandensis. Soil metabolism analysis revealed that pathways associated with amino acid metabolism was significantly enriched in O. highlandensis. Correlation analysis of bacterial diversity and soil metabolites revealed that the relative abundances of bacterial operational taxonomic units and the relative contents of metabolites were consistent. Our results provide insights into the microbial diversity and soil metabolism of naturally coexisting C. militaris and O. highlandensis.

Characteristics and source apportionment of particulate carbon in precipitation based on dual-carbon isotopes (13C and 14C) in Xi'an, China.

Wet deposition is a dominant removal pathway of carbonaceous particles from the atmosphere, but few studies have assessed the particulate carbon in precipitation in Chinese cities. To assess the characteristics and sources of particulate carbon, we measured the concentrations, fluxes, stable carbon isotopes, and radiocarbon of particulate carbon, and some cations concentrations in precipitation in Xi'an, China, in 2019. In contrast to rainfall samples, particulate carbon in snowfall samples in Xi'an showed extremely high concentrations and wet deposition fluxes. The concentrations as well as wet deposition fluxes showed no significant (p > 0.05) differences between urban and suburban sites, and they also exhibited low seasonality in rainfall samples. Water-insoluble organic carbon (WIOC) accounted for the majority (∼90%) of the concentrations and wet deposition fluxes of water-insoluble total carbon (WITC) in precipitation. The best estimates of source apportionment of WITC in precipitation showed that biological sources were the main contributor (80.0% ± 10.5%) in summer, and their contributions decreased to 47.3% ± 12.8% in winter. The contribution of vehicle exhaust emissions accounted for 11.7% ± 3.5% in summer and 39.0% ± 4.3% in winter, while the contributions of coal combustion were relatively small in summer (8.3% ± 7.0%) and winter (13.8% ± 8.5%). Biomass burning accounted for 25.7% ± 9.3% and 89.9% ± 0.7% of the biological sources in summer and winter, respectively, with the remainder comprising other sources of contemporary carbon. These results highlight the nonnegligible contributions of biogenic emissions and biomass burning to particulate carbon in precipitation in this city in summer and winter, respectively.

Six 19,20-epoxycytochalasans from endophytic Diaporthe sp. RJ-47.

Two new cytochalasins, deacetyl-19-epi-cytochalasin P1 (1), deacetyl-19,20-epoxycytochalasin D (2) were isolated from the endophytic fungus Diaporthe sp. RJ-47, along with four known compounds deacetyl-5,6-dihydro-7-oxo-19,20-epoxycytochalasin C (3), 19,20-epoxycytochalasin Q (4), 19,20-epoxycytochalasin C (5) and deacetyl-19,20-epoxy cytochalasin C (6). Their structures were unambiguously elucidated on the basis of the comprehensive analysis of extensive spectroscopic data. The antimicrobial effects of these compounds were evaluated.

[Therapeutic mechanism of Psammosilene tunicoides extract on rheumatoid arthritis based on NLRP3 inflammasome].

In this study, we investigated the mechanism of crude extract of Psammosilene tunicoides(CEPT) in the treatment of rheumatoid arthritis(RA) based on the Nod-like receptor protein 3(NLRP3) inflammasome. The collagen-induced arthritis(CIA) mouse model was established. On day 32 after the primary immunization, according to the arthritis score, the mice were randomly divided into model group, positive control(methotrexate) group, low-and high-dose CEPT groups, and normal group, with 10 mice in each group. According to the administration dose of each group, the mice were continuously administered for 21 days. Every four days during the administration, the paw edema degree, arthritis score, and spleen index of the mice were measured; histopathological examination was performed for the ankles of the mice; the contents of IL-1ß and IL-18 in the serum were determined; the protein expression levels of NLRP3, caspase-1, and apoptosis-associated speck-like protein containing a CARD(ASC), as well as the mRNA expression levels of NLRP3 and caspase-1 in the ankle joints of the mice were detected. The results showed that compared with those in the model group, the mice in the positive control group and CEPT groups had significantly decreased the contents of IL-1ß and IL-18 in the serum and spleen index(P<0.01), significantly lowered arthritis score and degree of paw edema(P<0.01), alleviated arthritic infiltration of the knee, and down-regulated protein and mRNA levels of NLRP3, ASC, and caspase-1 in the ankle joint(P<0.01). These results suggest that P. tunicoides may reduce the paw edema and arthritis score and alleviate the inflammatory response in CIA mice by inhibiting the expression of NLRP3. This study provides a basis for the study of immune regulation of P. tunicoides in RA.

[Influence of specification on chemical composition of dissolution and hepatocytes toxicity of Polygonum multiflorum].

According to different toxicities of various aqueous extracts of Polygonum multiflorum on hepatocyte, the impacts of chemical composition on the safety of P. multiforum was studied. In this study, 8 main chemical compositions in aqueous extracts of P. multiflorum were determined by the established HPLC method; at the same time, the inhibition ratios of different aqueous extracts of P. multiflorum on L02 cell were determined. Afterwards, the potential compounds related to the toxicity of P. multiforum were tentatively found through a multiple correlation analysis. The results showed that P. multiforum with different chemical compositions exhibited great differences in dissolution. The hepatocyte toxicity of P. multiflorum powder was much greater than P. multiflorum lumps. In addition, three constituents closely related to toxicity of P. multiflorum were found by multiple correlation analysis. The study revealed that chemical composition of P. multiflorum is closely related to the hepatotoxicity, and the hepatotoxicity of P. multiflorum powder is greater than that of other dosage forms. This study indicates that P. multiflorum with different chemical compositions show varying toxicity, which therefore shall be given high attention.