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ABSTRACT. Anticancer activity of Bombyx batryticatus ethanol extract (BBE) against HeLa cells was studied using cell viability, DNA fragmentation, real-time polymerase chain reaction, and Western blot analyses. The BBE inhibited the growth and induced apoptosis of HeLa cells. The MTT assay indicated that the BBE induced cytotoxicity in HeLa cells in a time-and concentration-dependent manner. When HeLa cells were treated for 48 h, the 50% inhibitory concentration (IC 50 ) value for the BBE was 1.564 mg/mL. The microscopy results showed that HeLa cells were severely distorted and showed slow growth; some cells became round in shape when treated with 5 mg/mL BBE for 24 h. The DNA ladder results revealed excessive DNA fragmentation in HeLa cells treated with 7 mg/mL BBE for 36 h. The proapoptotic activity of the BBE was attributed to its ability to modulate the expression of Bcl-2 and Bax genes. The mRNA and protein expression levels of Bax were remarkably higher whereas those of Bcl-2 were lower than those in the control cells; this led to an increased Bax/Bcl-2 ratio in cells treated with the BBE for 36 h. The results suggest that the BBE might play an important role in tumor growth suppression by inducing apoptosis in human cervical cancer cells via the regulation of the Bcl-2-and Baxmediated apoptotic pathways.

In this study, we investigated the physiological responses of maize with different amylose content at seedlings to drought stress. For waxy maize (WMS) and normal maize (NMS), the decline of photosynthesis under drought stress (DS) was due to the stomatal limitation. DS increased the non-photochemical quenching coefficient (NPQ), whereas decreased the activities of peroxidase (POD) and the plant height (PH), compared with the plants under normal irrigation. The content of starch increased and decreased significantly upon moderate and severe drought stress, respectively. For high amylose maize (HAMSs), they showed stomatal limitation upon moderate stress, while non-stomatal limitation upon severe stress. The NPQ and POD showed contrary trend compared with WMS and NMS. DS significantly decreased the starch content and PH of them. The principal component analysis (PCA) showed HAMSs were more sensitive to drought than WMS and NMS. The GBSSIIa level of HAMSs was also lower than that of WMS and NMS. Therefore, we conclude that HAMSs respond to DS through redox regulation to avoid oxidative damage, whereas WMS and NMS by increasing starch biosynthesis, and the higher GBSSIIa level may produce more amylose, which could promote the growth of maize under drought effectively.

The fermentation of Qu (FQ) could efficiently produce enzymatically modified starch at a low cost. However, it is poorly understood that how FQ influences the waxy maize starch (WMS) structure and the digestion behavior. In this study, WMS was fermented by Qu at different time and starches were isolated at each time point, and its physico-chemical properties and structural parameters were determined. Results showed that the resistant starch (RS), amylose content (AC), the average particle size [D(4,3)] the ratio of peaks at 1,022/995 cm–1, and the onset temperature of gelatinization (To) were increased significantly after 36 h. Conversely, the crystallinity, the values of peak viscosity (PV), breakdown (BD), gelatinization enthalpy (ΔH), and the phase transition temperature range (ΔT) were declined significantly after 36 h. It is noteworthy that smaller starch granules were appeared at 36 h, with wrinkles on the surface, and the particle size distribution was also changed from one sharp peak to bimodal. We suggested that the formation of smaller rearranged starch granules was the main reason for the pronounced increase of RS during the FQ process.

BACKGROUND Drought stress (DS) is the main abiotic stress that maize suffers during its whole growth period, and maize is also sensitive to DS. It had been demonstrated that DS could improve the quality of normal maize starch. However, waxy maize, which has special properties, has not been explored in depth, which limits the breeding and cultivation of waxy maize varieties and the application of waxy maize starch. Therefore, in this study, we investigated the effects of DS on the biosynthesis, structure, and functionality of waxy maize starch. RESULTS The results showed that DS decreased the expression level of SSIIb, SSIIIa, GBSSIIa, SBEI, SBEIIb, ISAII, and PUL, but increased the expression level of SSI and SBEIIa. DS did not change the average chain length of amylopectin, while increased the relative content of fa chains (RCfa) and decreased the RCfb1 and RCfb3. Furthermore, DS decreased the amylose content, amorphous lamellar distance da, semi‐crystalline repeat distance, and average particle size, whereas it increased the relative crystallinity, crystalline distance dc, the content of rapidly digested starch in the uncooked system and resistant starch content in both the uncooked and cooked system. Conclusions For waxy maize, DS could raise the relative expression level of SSI and SBEIIa, thus increasing RCfa. The larger number of RCfa could create steric hindrance, which can lead to producing more resistant starch in waxy maize starch. © 2023 Society of Chemical Industry.