Thirteen new peptaibols with antimicrobial activities from Trichoderma sp.

From the fungus Trichoderma sp., we isolated seven novel 18-residue peptaibols, neoatroviridins E-K (1-7), and six new 14-residue peptaibols, harzianins NPDG J-O (8-13). Additionally, four previously characterized 18-residue peptaibols neoatroviridins A-D (14-17) were also identified. The structural configurations of the newly identified peptaibols (1-13) were determined by comprehensive nuclear magnetic resonance (NMR) and high-resolution electrospray ionization tandem mass spectrometry (HR-ESI-MS/MS) data. Their absolute configurations were further determined using Marfey's method. Notably, compounds 12 and 13 represent the first 14-residue peptaibols containing an acidic amino acid residue. In antimicrobial assessments, all 18-residue peptaibols (1-7, 14-17) exhibited moderate inhibitory activities against Staphylococcus aureus 209P, with minimum inhibitory concentration (MIC) values ranging from 8-32 µg·mL-1. Moreover, compound 9 exhibited moderate inhibitory effect on Candida albicans FIM709, with a MIC value of 16 µg·mL-1.

Evaluating the release and metabolism of ricinine from castor cake fertilizer in soils using a LC-QTOF/MS coupled with SIRIUS workflow.

Castor cake is a major by-product generated after castor oil extraction and has been widely used as an organic fertilizer. Once applied to soil, a toxic alkaloid ricinine in castor cake may be released into soils and subsequently taken up by crops, which poses a potential threat to food safety and human health. However, the environmental fate of castor cake derived ricinine in agroecosystems remains unclear. In this study, the release and metabolism of ricinine in soils were conducted using soil pot experiments with different castor cake application rates. The analytical methodology of ricinine quantification in soil pore water was first established using solid phase extraction (SPE) coupled with liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). A non-target screening workflow associated with LC-QTOF/MS and SIRIUS platform was further developed to identify ricinine metabolites in soil pore water. After castor cake application, the ricinine concentrations in soil pore water significantly increased to 297-7990 µg L-1 at 1 day and then gradually decreased to 62.1-3460 µg L-1 at 7 days and 1.70-279 µg L-1 at 14 days for the selected two tested soils with castor cake application rates of 2, 10, and 20 g castor cake/kg soil. In addition, two ricinine metabolites R-194 and R-180 were tentatively identified and one ricinine metabolite N-demethyl-ricinin was confirmed through authentic reference standard for the first time by the developed non-target screening workflow. This study highlights the release and metabolism of toxic alkaloid ricinine in soils once applied castor cake as an organic fertilizer. Ricinine could be released into soil pore water in a short-term after castor cake application and then undergo demethylation, hydroxylation, and hydroxylation followed by methylation metabolisms over time in agroecosystems.

[Soil Properties, Heavy Metal Accumulation, and Ecological Risk in Vegetable Greenhouses of Different Planting Years].

The vegetable greenhouse soils in Yanglou Town, Ruzhou City, Henan Province were taken as the research object in the present study to explore the difference in soil physical and chemical properties and the total and fraction of heavy metals of different planting years. The potential ecological risks of heavy metals in greenhouse soils with different planting years were assessed by using single and comprehensive potential ecological risk index methods. The results showed that the soil pH of vegetable greenhouses increased, and fertility factors such as organic matter, available phosphorus, and alkali-hydrolyzable nitrogen accumulated to a certain extent compared to the control group, whereas catalase showed a decreasing trend. Correlation analysis showed that the planting years were significant positively correlated with pH (P<0.05) and organic matter (P<0.01) and significant negatively correlated with catalase (P<0.01). The amount of heavy metals in the vegetable greenhouse soils increased with the increase in planting years, among which Cu, Zn, and Cd increased most obviously, with maximum increases of 129.14%, 204.17%, and 161.11%, respectively. The proportion of acid-soluble and reducible heavy metals in the vegetable greenhouse soils also increased gradually with the planting years, and the proportion of residual heavy metals decreased correspondingly, which resulted in the heavy metals transforming into fractions easily absorbed by plants. The results of the single potential ecological risk index showed that Cd in vegetable greenhouse soils had a strong ecological risk with the increase in planting years, whereas Cu, Pb, Zn, and Ni were in the mild risk category. The comprehensive potential ecological risk index showed that the heavy metals in the vegetable greenhouse soils of different planting years have reached a strong or very strong ecological risk.

[Distribution Characteristics of Carbon, Nitrogen, and Phosphorus Bearing Pollutants in the Ancient Town Rivers of Suzhou].

Suzhou is a water-deficient city with water quality issues. Despite water conservation measures, emission reductions, source control, and pollution interception, water quality remains poor. To understand the total mass and distribution characteristics of carbon, nitrogen, and phosphorus bearing pollutants and inform decisions regarding river dredging, sediment and water samples were collected from 20 representative sections in the town's rivers during the spring of 2019. The depths of the sediments were measured along with the concentrations of carbon, nitrogen, and phosphorus bearing pollutants in the sediments and water, and the pollution degree was evaluated. Variations in various parameters were predicted for change water, diversion water, rainfall, and dredging. The results show that the sediment depths ranged between 22 and 1025 mm (average=266 mm), and the total mass of sediment was approximately 5.2×105 t in the ancient town rivers of Suzhou. The average proportions and concentrations of TOC, TN, NH4+-N, TP, and AP in the sediments were 3.4%, 2074 mg·kg-1, 140.2 mg·kg-1, 1765 mg·kg-1, and 57.2 mg·kg-1, respectively, indicating a moderate level of pollution. The concentration of TP in the sediments at 90% of the sampling points exceeds the national standard. Huancheng River was found to have the highest concentration of TP, suggesting that dredging shuld be targeted here first. In the water samples, the average concentrations of TOC, BOD5, COD, TN, NH4+-N, Kjeldahl nitrogen, TP, and PO43--P were 7.8, 0.6, 13.1, 2.5, 0.643, 1.3, 0.18, and 0.09 mg·L-1, respectively, indicating a severe level of pollution. Overall, water quality in these rivers falls below Class V surface water, and the concentration of TN seriously exceeds the national standard. Based on the patterns of total carbon mass and nitrogen and phosphorus bearing pollutants, the recommended order of dredging in Suzhou is the Huancheng River, the northern rivers of the ancient town, Ganjiang River, and the southern rivers of the ancient town. Under the rainfall scenario, the initial concentrations of pollutants in runoff were high, which leads to a decline in water quality. The total mass of TN in the water was reduced by 0.2 t under the change water and diversion water scenarios, and was further reduced by 4.58 t and 2.19 t, respectively, after dredging. Phosphorus bearing pollutants in the sediment were mainly imported from other sources, meaning that the total mass of TP in the water may increase following dredging activities.

A new phthalazinone derivative and a new isoflavonoid glycoside from lichen-associated Amycolatopsis sp.

A new phthalazinone derivative, named amycophthalazinone A (1), and a new isoflavonoid glycoside, 7-O-methyl-5-O-α-L-rhamnopyranosylgenestein (2), along with an isoflavonoid glycoside, 7-O-α-D-arabinofuranosyl daidzein (3) firstly found from natural sources, and eight known compounds (4-11), were isolated from the culture broth of the lichen-associated Amycolatopsis sp. YIM 130642. The structures of new compounds were elucidated on the basis of spectroscopic analysis. Compound 1 was the first example of naturally occurring phthalazinone derivative. The antimicrobial activities of all compounds towards five pathogenic strains were evaluated by a broth microdilution assay. Compound 1 exhibited the most potent inhibitory activity against Staphylococcus aureus, Salmonella typhi, and Candida albicans with MIC values of 32, 32, and 64 µg/mL, respectively.

Polyoxygenated Cyclohexenoids with Promising α-Glycosidase Inhibitory Activity Produced by Phomopsis sp. YE3250, an Endophytic Fungus Derived from Paeonia delavayi.

Seven new polyoxygenated cyclohexenoids, namely, phomopoxides A-G (1-7), were isolated from the fermentation broth extract of an endophytic fungal strain Phomopsis sp. YE3250 from the medicinal plant Paeonia delavayi Franch. The structures of these compounds were established by spectroscopic interpretation. The absolute configurations of compounds 1 and 4 were confirmed by X-ray crystallographic analysis and chemical derivative approach. All isolated compounds showed weak cytotoxic activities toward three human tumor cell lines (Hela, MCF-7, and NCI-H460) and weak antifungal activities against five pathogenic fungi (Candida albicans, Aspergillus niger, Pyricularia oryzae, Fusarium avenaceum, and Hormodendrum compactum). In addition, compounds 1-7 showed a promising α-glycosidase inhibitory activity with IC50 values of 1.47, 1.55, 1.83, 2.76, 2.88, 3.16, and 2.94 mM, respectively, as compared with a positive control of acarbose (IC50 = 1.22 mM).