The activities of antioxidative enzymes and the concentration of malondialdehyde were assayed in cucumber leaves (Cucumis sativus L.) 0, 6, 12, 24, 48, 72, and 96 h after the cucumber seedlings were infested by Bemisia tabaci (Gennadius). The results indicated that the activities of antioxidative enzymes were increased after herbivore infestation, including superoxide dismutase (SOD), and peroxidase (POD), and the levels of malondialdehyde (MDA), which is a product of membrane lipid peroxidation in the leaves. The enzymes and MDA showed peaks of different activity levels at 24 and 48 h after the infestation. SOD activity reached the highest peak, 10.4% higher than control, at 24 h, POD activity reached the highest peak, 213.2% higher than control, at 6 h, catalase (CAT) activity was not statistically significant compared with the control, and MDA content reached the highest peak, 59.9% higher than control, at 48 h. The results suggested that the enhanced activities of antioxidative enzymes and MDA content may contribute to bioprotection of cucumber plants against B. tabaci infestation.
Spodoptera frugiperda is a significant migratory invasive pest, identified as a serious threat to agricultural production and food security in China. However, to our knowledge, the effects of most host plants on the biological characteristics of S. frugiperda have not been well studied. To develop effective management strategies for S. frugiperda in its new invasive habitat, basic biological and ecological knowledge of this pest are crucial requirements. Here, we examined the effects of six cash crops maize, wheat, soybean, tomato, cotton and Chinese cabbage on the development, survival, fecundity of S. frugiperda by using the age-stage, two-sex life table. The preadult stage, adult preoviposition period and total preoviposition period of S. frugiperda were shortest on maize and wheat but were longest on tomato. Fecundity was greatest on maize and wheat but smallest on tomato. The highest intrinsic rate of increase, finite rate of increase, net reproductive rate and the shortest mean generation time were recorded on maize. This present study showed that S. frugiperda could cause great economic losses to these cash crops, which should attract the attention of agricultural management departments. Our findings provide useful information in predicting population dynamics and understanding the potential damage that could be incurred by S. frugiperda invasion.
Human immunodeficiency virus (HIV)–positive cases have been reported among people who injected drugs in Liangshan Prefecture in southwest of China since 1995 and Liangshan has become one of the most seriously affected epidemic areas in China. In 2004, several patients with HIV/acquired immunodeficiency syndrome (AIDS) initiated antiretroviral treatment (ART) at the Central Hospital of Liangshan Prefecture. From 2005 to 2013, the number of patients receiving ART dramatically increased.We conducted a retrospective cohort study to analyze the long-term survival time and associated factors among patients with HIV/AIDS who received ART in Liangshan Prefecture for the first time. Data were collected from the Chinese AIDS Antiretroviral Therapy DATAFax Information System. A life table and the Kaplan–Meier and Cox proportion hazard regression were used to calculate the survival time and its associated factors, respectively.Among 8310 ART-naïve patients with HIV/AIDS who initiated ART, 436 patients died of AIDS-related diseases, and their median time of receiving ART was 15.0 ± 12.3 months, whereas 28.7% of them died within the first 6 months after treatment. The cumulative survival rates of those receiving ART in 1, 2, 3, 4, and 5 years were 97.1%, 93.4%, 90.6%, 88.8%, and 86.0%, respectively. Multivariate Cox regression analysis showed that male patients on ART were at a higher risk of death from AIDS-related diseases (adjusted hazard ratio [AHR] = 1.5, 95% confidence interval [CI]: 1.1–2.1) than female patients. Patients infected with HIV through injection drug use (IDU) were at a higher risk of death (AHR = 1.6, 95% CI: 1.2–2.2) than those infected through heterosexual transmission. Patients with a baseline CD4 cell count <50/mm3 (AHR = 9.8, 95% CI: 6.0–15.9), 50–199/mm3 (AHR = 3.3, 95% CI: 2.3–4.6), and 200–349/mm3 (AHR = 1.7, 95% CI: 1.2–2.3) were at a higher risk of death than those with a CD4 cell count ≥350/mm3.ART prolonged survival time of patients with HIV/AIDS and improved their survival probability. Patients with HIV/AIDS should be consistently followed up and the CD4 T-cell count regularly monitored, and timely and early antiretroviral therapy initiated in order to achieve a better survival rate.
Aphidius gifuensis is one of the most important aphid natural enemies and has been successfully used to control Myzys persicae and other aphid species. High temperature in summer is one of the key barriers for the application of A. gifuensis in the field and greenhouse. In this work, we investigated the biological performance of A. gifuensis and the response of heat-shock proteins and antioxidant enzymes under high temperature. The results showed that A. gifuensis could not survive at 40°C and female exhibited a higher survival in 35°C. Furthermore, the short term exposure to high temperature negatively affected the performance of A. gifuensis especially parasitism efficiency. Under short-term heating, the expression of AgifsHSP, Agifl(2)efl, AgifHSP70, AgifHSP70-4 and AgifHSP90 showed an increased trend, whereas AgifHSP10 initially increased and then decreased. In 35°C, the expressions of Agifl(2)efl, AgifHSP70-4 and AgifHSP90 in female were higher than those in male, whereas the expression of AgifHSP70 exhibited an opposite trend. Besides the HSPs, we also quantified the expression levels of 11 antioxidant enzyme genes: AgifPOD, AgifSOD1, AgifSOD2, AgifSOD3, AgifCAT1, AgifCAT2, AgifGST1, AgifGST2, AgifGST3, AgifGST4 and AgifGST5. We found that the sex-specific expression of AgifSOD2, AgifSOD3, AgifPOD, AgifGST1 and AgifGST3 were highly consistent with sex-specific heat shock survival rates at 35°C. Furthermore, when the temperature was above 30°C, the activities of GST, SOD, CAT and POD were significantly increased; however, there was no significant difference of the CAT activity between the male and female at 35°C. Collectively, all of these results suggested that the protection of thermal damage is coordinated by HSPs and antioxidant enzymes in A. gifuensis. Based on the heat tolerance abilities of many aphid natural enemies, we also discussed an integrated application strategy of many aphid enemies in summer.
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