Simulating immunosuppressive mechanism of Microplitis bicoloratus bracovirus coordinately fights Spodoptera frugiperda

Parasitoid wasps control pests via a precise attack leading to the death of the pest. However, parasitoid larvae exhibit self-protection strategies against bracovirus-induced reactive oxygen species impairment. This has a detrimental effect on pest control. Here, we report a strategy for simulating Microplitis bicoloratus bracovirus using Mix-T dsRNA targeting 14 genes associated with transcription, translation, cell-cell communication, and humoral signaling pathways in the host, and from wasp extracellular superoxide dismutases. We implemented either one-time feeding to the younger instar larvae or spraying once on the corn leaves, to effectively control the invading pest Spodoptera frugiperda. This highlights the conserved principle of "biological pest control," as elucidated by the triple interaction of parasitoid-bracovirus-host in a cooperation strategy of bracovirus against its pest host.

Effects of cadmium exposure on metabolism, antioxidant defense, immune function, and the hepatopancreas transcriptome of Cipangopaludina cathayensis

Cadmium (Cd) is a common contaminant in aquatic environments. However, little is known about the mechanisms underlying Cd toxicity in the freshwater snail Cipangopaludina cathayensis (Heude, 1890). This study to investigate the toxic effects of Cd on the standard metabolism, antioxidant activities, immune function, and hepatopancreas transcriptome profiles of C. cathayensis. C. cathayensis was exposed to 0.25, 0.5, 1.0, or 1.5 mg/L Cd for 3 h, with results showing that Cd significantly inhibited oxygen consumption and ammonia excretion and disrupted the respiratory metabolism of C. cathayensis. In addition, the O:N ratio dropped below 7, indicating that C. cathayensis may rely exclusively on proteins as an energy source under Cd stress. To understand how Cd impacts the antioxidant activities, immune function, and transcriptional profiles, C. cathayensis were exposed to 0.5 (low exposure, L14) or 1.5 (high exposure, H14) mg/L Cd for 14 days. Our results indicate that Cd exposure leads to oxidative stress and immunosuppression, with the latter effect being larger for exposure to higher Cd concentrations. A total of 2172 differentially expressed genes (DEGs) were identified by transcriptome analysis of the hepatopancreas, of which 885 were upregulated and 1287 were downregulated. Gene ontology and KEGG analyses revealed that the DEGs in the H14 group are enriched for energy generation terms and the "oxidative phosphorylation" pathway, respectively. Therefore, up-regulation of energy metabolism may be an adaptive strategy under Cd stress. Moreover, several genes involved in antioxidant activity were downregulated, whereas genes related to reactive oxygen species generation were upregulated. In addition, many immunity-related genes were identified within the DEGs, indicating that Cd toxicity may affect immune defense. Further, DEGs in the H14 group were enriched for disease-associated pathways. Taken together, our results indicate that Cd exposure leads to metabolic disorders, oxidative stress, and immunosuppression and thus may potentially contribute to disease outbreaks.

[Tajectories of the self-efficacy of HIV testing among MSM based on latent class growth model]

Objective: To analyze the trajectories of HIV testing self-efficacy among men who have sex with men (MSM) based on latent class growth model. Methods: From August 2019 to May 2021, 404 MSM were recruited in Shandong Province and subjected to a 1-year follow-up study with individual intervention (pushing intervention pictures and videos in WeChat and follow-up questionnaires) and community intervention (forwarding to friends and sharing and discussing HIV testing-related information in WeChat groups). The level of HIV testing self-efficacy among MSM was measured. The long-term trend of HIV testing self-efficacy was analyzed using the latent class growth model (LCGM), and the influencing factors of the trend were analyzed. Results: A total of 404 MSM were (28.25±8.95) years old, with the oldest being 58 and the youngest being 18. The scores of HIV testing self-efficacy M(Q₁, Q₃) at baseline and 4 follow-ups were 18.00 (17.00, 21.00), 19.00 (18.00, 22.00), 19.00 (18.00, 22.00), 19.00 (18.00, 22.00) and 19.00 (18.00, 22.00). The results of the freely estimated two-category LCGM model showed that the trend of HIV testing self-efficacy among MSM could be divided into two classes, "intervention response group" [255(63.1%)] and "intervention non-response group" [149(36.9%)]. The former had a higher level of HIV testing self-efficacy which tended to increase at first and then decrease over time, while the latter had a lower and more stable level. The results of the multifactorial logistic regression analysis showed that the OR values of MSM in business or service and jobless or unemployed were 0.261 (95%CI: 0.108-0.633) and 0.186 (95%CI: 0.057-0.610), respectively, using the students as the reference group. Conclusion: There is a group heterogeneity in the trend of HIV testing self-efficacy in the intervention conditions among MSM, and occupation may be an influencing factor.