Application potential of biofertilizer-assisted Pennisetum giganteum in safe utilization of mercury-contaminated paddy fields.

High mercury (Hg) bioaccumulation in crops such as rice in Hg-contaminated areas presents a potential health hazard to humans and wildlife. To develop a safe alternative technique, bacillus-inoculated biofertilizer, citric acid, earthworms, and selenium-modified activated clay were compared for their ability to regulate Hg bioaccumulation in Pennisetum giganteum (P. giganteum). This biofertilizer significantly increased Bacillus sp. abundance in the soil by 157.12%, resulting in the removal of 27.52% of water-soluble Hg fractions through volatilization and adsorption mechanisms. The variation in bioavailable Hg in the soil significantly reduced the total Hg concentration in P. giganteum young leaves, old leaves, stems, and roots of P. giganteum by 74.14%, 48.08%, 93.72%, and 50.91%, respectively (p < 0.05), which is lower than the Chinese feed safety standard (100 ng g-1). The biofertilizer inhibitory potential was highly consistent with that of the selenium-modified activated clay. Biofertilizers significantly reduced the methylmercury concentration in various P. giganteum tissues (p < 0.05), whereas selenium-modified activated clay failed to achieve a comparable effect. This biofertilizer-assisted planting pattern can achieve an economic income quadruple that of the rice planting pattern in the Hg-contaminated paddy fields. Because of its significant environmental and financial applications, the biofertilizer-assisted planting pattern is expected to replace Hg-contaminated paddy fields.

Cordycepin and N6-(2-hydroxyethyl)-adenosine from Cordyceps pruinosa and their interaction with human serum albumin.

Cordyceps pruinosa (CP) is often used as Traditional Chinese Medicine, but the substance basis of its medicinal properties is unclear. In this study, two compounds were isolated from CP cultures by column chromatography, and identified as cordycepin and N6-(2-hydroxyethyl)-adenosine (HEA) by Nuclear Magnetic Resonance. In order to understand the efficacy of these two substances as potential therapeutic agents, it is necessary to explore their binding with proteins. The molecular mechanisms of interaction between cordycepin, HEA and human serum albumin (HSA) were studied using UV and fluorescence spectroscopy. The bingding constants between HSA and cordycepin were 4.227, 3.573 and 3.076 × 10(3)·at 17, 27 and 37°C respectively, and that of HSA and HEA were 27.102, 19.409 and 13.002 × 10(3)·at the three tempretures respectively. Both cordycepin and HEA can quench the intrinsic fluorescence of HSA via static quenching, and they can bind with HSA to form complexes with a single binding site. The interaction forces between cordycepin and HSA were determined as electrostatic and hydrophobic, and those of HEA and HSA were hydrogen bonding and van der Waals forces. Using Foster's equation, the distance between fluorophores of cordycepin and HSA, and HEA and HSA are estimated to be 5.31 nm and 4.98 nm, respectively. In this study, cordycepin was isolated for the first time from CP, and will provide a new source of cordycepin and expand the use of this taxon. The interaction mechanisms between cordycepin and HSA was studied for the first time, which will provide a useful guide for the clinical application of cordycepin. The pharmacological importance of this study is to understand the interaction of HSA with cordycepin and HEA, which will be essential for the future designing of drugs based on the two compounds.

[Screening and taxonomic identification of endophytic fungi with antitumor and antioxidant activities from Artemisia lactiflora].

Artemisia lactiflora is an important medicinal plant in China. The antitumor and antioxidant activities of the extracts of 54 endophytic fungi from the plant were screened via MTT assay and DPPH scavenging radical assay, respectively. The bioactive strains were identified based on similarity of 5.8S gene and internal transcribed spacer (ITS) sequences. The results showed that extracts from ten (18.5%) isolates exhibited antitumor activity, and which from two (3.7%) isolates exhibited antioxidant activity. The Alternaria sp. GYBH47 strain was simultaneously having antagonistic activity against HL-60 leukemia, MCF-7 breast and COLO205 colon cell lines, and Phomopsis sp. GYBH42 strain having cytotoxic and antioxidant activities. The results indicated that endophytic fungi from Artemisia lactiflora are potential resources to find valuable bioactive components.