RESUMO
Cadmium (Cd) stress is one of the principal abiotic stresses that inhibit maize growth. The research was to explore (hemin chloride) Hemin (100 µmol L-1) on photosynthesis, ascorbic acid (AsA)-glutathione (GSH) cycle system, and polyamine metabolism of maize under Cd stress (85 mg L-1) using nutrient solution hydroponics, with Tiannong 9 (Cd tolerant) and Fenghe 6 (Cd sensitive) as experimental materials. The results showed that Hemin can increase leaf photosynthetic pigment content and ameliorate the ratio of Chlorophyll a/chlorophyll b (Chla/Chlb) under Cd stress. The values of ribose 1, 5-diphosphate carboxylase/oxygenase (RuBPcase) and phosphoenolpyruvate carboxylase (PEPCase), and total xanthophyll cycle pool [(violoxanthin (V), antiflavin (A) and zeaxanthin (Z)] increased, which enhancing xanthophyll cycle (DEPS) de-epoxidation, and alleviating stomatal and non-stomatal limitation of leaf photosynthesis. Hemin significantly increased net photosynthetic rate (Pn ), stomatal conductance (gs ), transpiration rate (Tr ), photochemical quenching coefficient (qP), PSII maximum photochemical efficiency (Fv/Fm ), and electron transfer rate (ETR), which contributed to the improvement of the PSII photosynthetic system. Compared with Cd stress, Hemin can reduce thiobartolic acid reactant (TBARS) content, superoxide anion radical (O2 -) production rate, hydrogen peroxide (H2O2) accumulation, and the extent of electrolyte leakage (EL); decreased the level of malondialdehyde (MDA) content and increased the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT); slowed the decrease in dehydroascorbic acid reductase (DHAR) and monodehydroascorbate reductase (MDHAR) activity and the increase in glutathione reductase (GR) and ascorbate peroxidase (APX) activity in leaves; promoted the increase in AsA and GSH content, decreased dehydroascorbic acid (DHA) and oxidized glutathione (GSSG), and increased AsA/DHA and GSH/GSSG ratios under Cd stress. Hemin promoted the increase of conjugated and bound polyamine content, and the conversion process speed of free putrescine (Put) to free spermine (Spm) and spermidine (Spd) in maize; decreased polyamine oxidase (PAO) activity and increased diamine oxidase (DAO), arginine decarboxylase (ADC), ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) enzyme activities in leaves under Cd stress.
RESUMO
Liver cancer (HCC) is a common malignant tumor whose incidence is increasing worldwide, but existing chemotherapeutic agents are not ideally effective drugs and have considerable resistance to chemotherapy. Exosome microRNA-103 plays an important role in the proliferation and invasion of liver cancer cells. The purpose of this article is to investigate the role and mechanism of exosome microRNA-103 in hepatocellular carcinoma cell proliferation and invasion. 84 patients with hepatocellular carcinoma diagnosed in a hospital from June 2017 to June 2020 were selected. The average age was 60.13±6.99 years. When the patient was fasting, 3 mL of peripheral venous blood was taken. And 50 healthy control groups were established, with an average age of 59.98±8.18 years old. 3 ml of peripheral venous blood was collected on an empty stomach to compare the cell proliferation rate and invasion rate. The results of the study showed that the number of stage III hepatocellular carcinoma cells invaded at 6h was 68.9, and it changed to 89.4 at 12h, and 106.4 at 24h; compared with that, the cell invasion rate in stage IV was higher. The number of stage IV hepatocellular carcinoma invasions at 6h was 68, which changed to 94.5 at 12h and 112.4 at 24h.