RESUMEN
To investigate the effects of microplastics (MPs) on hydrolysis, acidification and microbial characteristics during waste activated sludge (WAS) anaerobic fermentation process, five different kinds of MPs were added into the WAS fermentation system and results indicated that, compared to the control group, the addition of polyvinyl chloride (PVC)-MPs exhibited the least inhibition on volatile fatty acids (VFAs), reducing them by 13.49 %. Conversely, polyethylene (PE)-MPs resulted in the greatest inhibition, with a reduction of 29.57 %. MPs, while accelerated the dissolution of WAS that evidenced by an increase of lactate dehydrogenase (LDH) release, concurrently inhibited the activities of relevant hydrolytic enzymes (α-Glucosidase, protease). For microbial mechanisms, MPs addition affected the proliferation of key microorganisms (norank_f_Bacteroidetes_vadinHA17, Ottowia, and Propioniclava) and reduced the abundance of genes associated with hydrolysis and acidification (pfkb, gpmI, ilvE, and aces). Additionally, MPs decreased the levels of key hydrolytic and acidogenic enzymes to inhibit hydrolysis and acidification processes. This research provides a basis for understanding and unveils impact mechanisms of the impact of MPs on sludge anaerobic fermentation.
RESUMEN
RATIONALE: Post-traumatic stress disorder (PTSD) is a complex, chronic psychiatric disorder typically triggered by life-threatening events and, as yet, lacks a specialized pharmacological treatment. The potential therapeutic role of ketamine, an N-methyl-D-aspartate receptor antagonist, in mitigating PTSD has been the subject of investigation. OBJECTIVE: The aim of this study was to elucidate alterations in the glycogen synthase kinase-3ß (GSK-3ß) signaling pathway in response to ketamine intervention, using the single prolonged stress (SPS) model of PTSD at a molecular level. METHODS: PTSD-like symptoms were simulated using the SPS model. Ketamine (10 mg/kg) and GSK-3ß antagonist SB216763 (5 mg/kg) were then administered intraperitoneally. Stress-related behavior was evaluated through the open field test (OFT) and the elevated plus maze test (EMPT). Additionally, brain activity was analyzed using quantitative electroencephalography (qEEG). Changes in protein and mRNA expressions of glucocorticoid receptor (GR), brain-derived neurotrophic factor (BDNF), GSK-3ß, phosphorylated ser-9 GSK-3ß (p-GSK-3ß), FK506 binding protein 5 (FKBP5), and corticotropin-releasing hormone (CRH) were assessed in the hypothalamus via western blot and qPCR. RESULTS: SPS-exposed rats exhibited reduced distance and time spent in the center of the open arms, a pattern divergent from control rats. qEEG readings revealed SPS-induced increases in alpha power, low gamma and high gamma power. Furthermore, SPS triggered an upregulation in the protein and gene expression of GSK-3ß, GR, BDNF, p-GSK-3ß, and FKBP5, and downregulated CRH expression in the hypothalamus. Ketamine administration following the SPS procedure counteracted these changes by increasing the time spent in the center of the OFT, the distance traversed in the open arms of the EMPT, and mitigating SPS-induced alterations in cerebral cortex oscillations. Moreover, ketamine reduced the protein levels of GSK-3ß, GR, p-GSK-3ß, and altered the ratio of p-GSK-3ß to GSK-3ß. Gene expression of GSK-3ß, GR, BDNF, and FKBP5 decreased in the SPS-Ket group compared to the SPS-Sal group. CONCLUSIONS: Ketamine appeared to remediate the abnormal GSK-3ß signaling pathway induced by SPS. These findings collectively suggest that ketamine could be a promising therapeutic agent for PTSD symptoms, working through the modulation of the GSK-3ß signaling pathway.
