Background: Shikonin, a natural naphthoquinone, is abundant in Chinese herb medicine Zicao (purple gromwell) and has a wide range of biological activities, especially for cancer. Shikonin and its analogues have been reported to induce cell-cycle arrest, but target information is still unclear. We hypothesized that shikonin, with a structure similar to that of quinone-type compounds, which are inhibitors of cell division cycle 25 (Cdc25) phosphatases, will have similar effects on Cdc25s. To test this hypothesis, the effects of shikonin on Cdc25s and cell-cycle progression were determined in this paper. Methods: The in vitro effects of shikonin and its analogues on Cdc25s were detected by fluorometric assay kit. The binding mode between shikonin and Cdc25B was modelled by molecular docking. The dephosphorylating level of cyclin-dependent kinase 1 (CDK1), a natural substrate of Cdc25B, was tested by Western blotting. The effect of shikonin on cell cycle progression was investigated by flow cytometry analysis. We also tested the anti-proliferation activity of shikonin on cancer cell lines by MTT assay. Moreover, in vivo anti-proliferation activity was tested in a mouse xenograft tumour model. Results: Shikonin and its analogues inhibited recombinant human Cdc25 A, B, and C phosphatase with IC₅₀ values ranging from 2.14 ± 0.21 to 13.45 ± 1.45 μM irreversibly. The molecular modelling results showed that shikonin bound to the inhibitor binding pocket of Cdc25B with a favourable binding mode through hydrophobic interactions and hydrogen bonds. In addition, an accumulation of the tyrosine 15-phosphorylated form of CDK1 was induced by shikonin in a concentration-dependent manner in vitro and in vivo. We also confirmed that shikonin showed an anti-proliferation effect on three cancer cell lines with IC₅₀ values ranging from 6.15 ± 0.46 to 9.56 ± 1.03 μM. Furthermore, shikonin showed a promising anti-proliferation effect on a K562 mouse xenograph tumour model. Conclusion: In this study, we provide evidence for how shikonin induces cell cycle arrest and functions as a Cdc25s inhibitor. It shows an anti-proliferation effect both in vitro and in vivo by mediating Cdc25s.

The potato plant is one of the main crops in the world. However, relatively little is known about key virulence factors of major fungal and bacterial diseases in potatoes, biocontrol measures to improve activity and stability, and the core driving forces in the control process. Here, we focus on analyzing the mechanisms by which genes, proteins, or (and) metabolites of potato pathogens as key virulence factors. Then, the single strain biocontrol agents, synthetic microbial communities, microbial microcapsule strategies were introduced, and the latter two strategies can improve stability and activity in biocontrol. Meanwhile, summarized the defense mechanisms of biocontrol and their specific issues in practical applications. Furthermore, explore how potato crop management, soil management, and climate effects, as crucial driving forces affect potato biocontrol in the system. Dynamic and systematic research, excavation of biocontrol strain resources, find the causes of regional disease resistance and exploration of biocontrol mechanism will provide promising solutions for biotic stress faced by potato in the future.

The potato dry rot disease caused by Fusarium spp. seriously reduces potato yield and threatens human health. However, potential biocontrol agents cannot guarantee the stability and activity of biocontrol. Here, 18 synthetic microbial communities of different scales were constructed, and the synthetic microbial communities with the best biocontrol effect on potato dry rot disease were screened through in vitro and in vivo experiments. The results show that the synthetic community composed of Paenibacillus amylolyticus, Pseudomonas putida, Acinetobacter calcoaceticus, Serratia proteamaculans, Actinomycetia bacterium and Bacillus subtilis has the best biocontrol activity. Metabolomics results show that Serratia protoamaculans interacts with other member strains to produce caproic acid and reduce the disease index to 38.01%. Furthermore, the mycelial growth inhibition after treatment with caproic acid was 77.54%, and flow cytometry analysis showed that the living conidia rate after treatment with caproic acid was 11.2%. This study provides potential value for the application of synthetic microbial communities in potatoes, as well as the interaction mechanisms between member strains of synthetic microbial communities.

Triterpenoids possess a wide range of biological effects. Here, the cytotoxic activities of 55 triterpenes and derived glycosides against BEL-7404 and SGC-7901 cells were assessed, and structure-activity relationships were analysed accordingly. Nine of them effectively inhibited the two cell lines. In particular, compounds 49 and 52 inhibited BEL-7404 cells as efficiently as 5’-fluorouracil (IC₅₀ values 0.46 and 1.48, respectively). Moreover, we found that compounds 49 and 52 induced apoptosis in BEL-7404 cells. Indeed, DNA fragmentation assay showed a time-dependent degradation of DNA after treatment of cells with compounds 49 and 52. In addition, Bax gene expression levels were increased after treatment with these compounds, in a concentration-dependent manner. Taken together, our findings suggested that compounds 49 and 52 induce apoptosis in BEL-7404 cells by upregulating the Bax gene without affecting Bcl-2 gene expression.

To develop a new antiviral preparation from a microbial source, the halophilic bacterium Bacillus pumilus E303035 was isolated from a soil sample collected at Qarhan Salt Lake in Qinghai, China. The inhibitory activity of an ethyl acetate extract of its fermentation broth was higher than that of an n-butanol extract. After isolation and purification, 9 compounds were obtained: cyclo(L-Leu-L-Pro) (1), cyclo(L-Pro-L-Tyr) (2), Brevianamide F (3), 2-(3-Indolyl) ethanol (4), N-[2-(1H-indol-3-yl) ethyl] acetamide (5), 3, 3-di(1H-indol-3-yl)propane-1,2-diol (6), Lincomycin B (7), dibutylphthalate (8), and p-hydroxyphenethyl alcohol (9). Compounds 1, 5, and 9 showed inhibitory activities against potato virus Y (PVY). Compounds 1, 4, and 9 had significant inhibitory activity against genes HC-pro, P3, and Nib, compound 5 against gene P3, and compounds 1 and 4 against NIa. Compounds 1, 4, 5, and 9 had significant inhibitory activity against genes VPg and 6K1. Active compounds 1, 5, and 9 had various effects on the expression of viral genes related to pathogenesis. Expression of genes cullin and XTH was up-regulated and CP was down-regulated, compared to the positive control. In conclusion, compounds 1, 5, and 9 might be considered as potential antiviral agents for future development.

Quinoa (Chenopodium quinoa Willd.) is a traditional food originally from the Andes Mountains in South America. It was first planted in China in 1987 and is grown in Tibet, Gansu, and Qinghai provinces. In May 2021, 40% of 2-month-old quinoa plants in the 3.4 hm² experimental base of Qinghai University (36.7262° N, 101.7487° E) were found to have leaves with grey-brown subcircular spots (about 0.4 to 0.7 cm) with black dots (acervuli). Severely infected plants exhibited symptoms such as withered and stunted growth. The diseased-healthy junctions of infected leaves (0.5 cm) were cut out, disinfected with 3% NaClO for 1.5 min, washed three times with sterile water, dried, placed on water agar, and incubated at 25°C for 48 h. After sporulation was seen on the leaf surface, spore suspensions were prepared by placing conidia in sterile water using a pipette. Next, 200 μl of each spore suspension was spread on the surface of water agar and incubated at 25°C for 12 h. Single spores were selected under a stereomicroscope and cultured on potato dextrose agar (PDA) (Qi et al. 2022). The mycelium of two representative isolates (20DLMF-5-4-1 and 20DLMF-7-4-1) was grey-black with white edges and included a fluffy aerial mycelium. Conidia were unicellular, colorless, long ellipsoid or curved moon shaped, averaging 14.3 × 1.8 to 20.2 × 2.2 μm (n=100). The light brown appressoria were ovoid, averaging 8.5 × 5.2 to 7.7 × 4.1 μm (n=20). Spherical, dark brown acervuli were observed on the leaves, averaging 160 to 200 μm (n=20), and there were dark brown spiny bristles. The ITS, partial ACT, CHS, GAPDH and TUB2 genes were amplified from genomic DNA of the two isolates (Weir et al. 2012). Sequences were deposited in GenBank (accession no. OQ871595 to OQ871602 for ACT, CHS, GAPDH, and TUB2, and OQ860235 to OQ860236 for ITS) and showed over 99% identities with the corresponding sequences of C. spinaciae CBS125347 and CBS128.57 (Vu et al. 2019; Damm et al. 2009). Both isolates clustered with the type culture of C. spinaciae (CBS125347, CBS128.57), with 100% bootstrap support in the phylogenetic tree. Thus, according to the morphological and molecular characteristics, the two isolates were identified as C. spinaciae. Pathogenicity tests were conducted on 24 healthy, tender leaves of six 1-month-old quinoa plants, with three replicates (Yang et al. 2021). The leaves were gently scratched in 3-4 areas with a sterile needle. A conidial suspension (105 conidia/ml) of the two isolates was sprayed on these wounds. The control group was unscratched and sprayed with sterile water. The plants were incubated in a greenhouse at 25°C for 24 h in the dark and 7 days in the light. Tiny grey-brown spots appeared on day 3 (about 0.4 to 0.6 cm) and continued to enlarge until perforations and ruptures developed on day 7. Subsequently, acervuli were observed on the surface of the leaves. The control leaves remained healthy. Isolates were reisolated from the symptomatic leaves and they had the same morphological and molecular characteristics as the original isolates, confirming Koch's postulates. To our knowledge, this is the first report of C. spinaciae causing quinoa leaf anthracnose in China. C. spinaciae seriously affects the yield and quality of quinoa and has been previously reported to cause anthracnose of Vicia sativa in China (Wang et al. 2019). The results provide a basis for the study and control of quinoa leaf anthracnose.