Cytotoxicity of the natural herbicidal chemical, berberine, on Nicotiana tabacum Bright yellow-2 cells

Curcumin induces mitochondrial apoptosis in human hepatoma cells through BCLAF1-mediated modulation of PI3K/AKT/GSK-3β signaling

Curcumin is a yellow pigment extracted from the rhizome of turmeric, a traditional Chinese medicine. Here, we tested the hypothesis that curcumin-mediated downregulation of BCLAF1 triggers mitochondrial apoptosis in hepatoma cells by inhibiting PI3K/AKT/GSK-3β signaling. Treatment of the human hepatoma cell lines, HepG2 and SK-Hep-1, with various concentrations of curcumin revealed a time-dependent and concentration-dependent inhibition of cell proliferation, increased apoptosis, cell cycle arrest at the G0/G1 phase, reduced mitochondrial membrane potential, and reduced expression levels of PI3K, p-PI3K, AKT, p-AKT, GSK-3β, and p-GSK-3β. Additionally, curcumin suppressed the levels of apoptotic factors after treating the cells with LY294002, a PI3K inhibitor. Curcumin also suppressed the expression of BCLAF1. Treating stable BCLAF1 knockout HepG2 and SK-Hep-1 cells with curcumin further enhanced apoptosis and increased the number of cells in G0/G1 cell cycle arrest, while inhibiting the downregulation of PI3K/AKT/GSK-3β pathway-related proteins. Treatment of a nude mouse xenograft model bearing HepG2 cells with curcumin inhibited tumor growth, disrupted the cellular structure of the tumor tissue, and suppressed the expression of BCLAF1 and PI3K/AKT/GSK-3β proteins. In summary, our in vitro and in vivo analyses show that curcumin downregulates BCLAF1 expression, inhibits the activation of the PI3K/AKT/GSK-3β pathway, and triggers mitochondrial apoptosis in HCC. These findings uncover a potential therapeutic strategy leveraging the antitumor effects of curcumin against HCC.

Natural herbicidal alkaloid berberine regulates the expression of thalianol and marneral gene clusters in Arabidopsis thaliana

BACKGROUND

Berberine is a plant-derived herbicidal alkaloid. The herbicidal mechanism of berberine is still not clear. In this study, our aim is to clarify the mechanism of berberine inhibiting the root growth of Arabidopsis thaliana, aiming at providing new insight into identifying the molecular targets of berberine.

RESULTS

The whole-genome RNA sequencing had revealed that 403 genes were down-regulated, and 422 genes were up-regulated in Arabidopsis roots with berberine treatment. According to KEGG and GO analysis, the expression of two genes AT5G48010 (Thas) and AT5G42600 (MRN1) which are in the sesquiterpenoid and triterpenoid biosynthesis pathway were affected most. These two genes belong to thalianol and marneral gene clusters. RT-PCR showed that Arabidopsis responds to berberine by inhibiting root growth through repressing the expression of thalianol and marneral gene clusters, which was independent of the upstream effectors ARP6 and HTA9-1. GC-MS analysis showed that berberine could inhibit THAH in the biosynthetic network of triterpenoid gene cluster in Arabidopsis and thus cause the accumulation of thalianol.

CONCLUSION

Our study indicated the repression of the thalianol and marneral gene clusters as the primary mechanism of action of berberine in Arabidopsis, which may result in plant growth defects by interrupting the thalianol metabolic pathway. This provides novel clues as to the possible molecular herbicidal mechanism of berberine. © 2022 Society of Chemical Industry.

Novel combined biological antiviral agents Cytosinpeptidemycin and Chitosan oligosaccharide induced host resistance and changed movement protein subcellular localization of tobacco mosaic virus

Plant viral diseases cause severe economic losses in agricultural production. Development of microorganism-derived antiviral agents provides an alternative strategy to efficiently control plant viral diseases. In this study, the antiviral effect and mechanism of a combined biological agent Cytosinpeptidemycin and Chitosan oligosaccharide (CytPM-COS) were investigated. CytPM-COS effectively inhibited tobacco mosaic virus (TMV) in Nicotiana glutinosa, suppressed viral RNA and CP accumulation in BY-2 protoplast and affected the subcellular localization as well as punctate formation of TMV MP in N. benthamiana leaves. In addition, CytPM-COS triggered reactive oxygen species (ROS) production and induced up-regulation of various defense responsive genes including PR-1, PR-5, FLS2, Hsp70. Our results indicated that CytPM-COS can potentially act as a pesticide for integrated control of plant viruses in the future.

Physiological and Biochemical Mechanisms Mediated by Allelochemical Isoliquiritigenin on the Growth of Lettuce Seedlings

Isoliquiritigenin, a natural chalcone-type flavonoid, has been recognized as an allelochemical with phytotoxicity to lettuce; however, not enough attention has been paid to the mechanisms of this secondary metabolite. In this work, we investigated the physiological and biochemical mechanisms of isoliquiritigenin on lettuce seedlings. The results show that isoliquiritigenin has a concentration-dependent inhibitory effect on radicle elongation of lettuce seedlings, but no significant impact on lettuce germination. Microscopy analyses suggest that the surface morphology of lettuce radicle tips was atrophied and the intracellular tissue structure deformed at high concentrations. Isoliquiritigenin induced the overproduction of reactive oxygen species (ROS), which led to loss of cell viability in the radicle cells. In addition, malondialdehyde (a product of lipid peroxidation) and free proline levels were found to have increased, while chlorophyll content in lettuce seedlings decreased. All these changes suggest that the primary allelopathic mechanism of isoliquiritigenin by which it inhibits radicle elongation in lettuce seedlings might be due to the overproduction of ROS, which causes oxidative damage to membrane lipids and cell death.

Pesticides and herbicides

This paper provides a review of some important scientific articles published in the year 2018 about pesticides and herbicides. The literature review presented in this paper cover pesticides and herbicides presence as well as occurrence in the environment. The review is divided into four sections. Each of these sections highlight issues related to pesticides and herbicides on toxicology, ecology, risk assessment, modeling, and treatment strategies.