In-situ construction of biomineralized cadmium sulfide-Rhodopseudomonas palustris hybrid system: Mechanism of synergistic light utilization.

Sulfide biomineralization is a microorganism-induced process for transforming the environmentally hazardous cadmium into useful resource utilization. This study successfully constructed cadmium sulfide nanoparticles-Rhodopseudomonas palustris (Bio-CdS NPs-R. palustris) hybrids. For the self-assembling hybrids, Bio-CdS NPs were treated as new artificial-antennas to enhance photosynthesis, especially under low light (LL). Bacterial physiological results of hybrids were significantly increased, particularly for cells under LL, with higher enhancement photon harvesting ability. The enhancement included the pigment contents, and the ratio of the peripheral light-harvesting complex Ⅱ (LH2) to light-harvesting Ⅰ (1.33±0.01 under LL), leading to the improvements of light-harvesting, transfer, and antenna conversion efficiencies. Finally, the stimulated electron chain of hybrids improved bacterial metabolism with increased nicotinamide adenine dinucleotide (NADH, 174.5% under LL) and adenosine triphosphate (ATP, 41.1% under LL). Furthermore, the modified photosynthetic units were induced by the up-regulated expression of fixK, which was activated by reduced oxygen tension of the medium for hybrids. fixK up-regulated genes encoding pigments (crt, and bch) and complexes (puf, pucAB, and pucC), leading to improved light-harvesting and transfer, and transform ability. This study provides a comprehensive understanding of the solar energy utilization mechanism of in-situ semiconductor-phototrophic microbe hybrids, contributing to further theoretical insight into their practical application.

Repetitive transcranial magnetic stimulation promotes motor function recovery in mice after spinal cord injury via regulation of the Cx43-autophagy loop.

Spinal cord injury (SCI) is a severe condition with an extremely high disability rate. It is mainly manifested as the loss of motor, sensory and autonomic nerve functions below the injury site. High-frequency transcranial magnetic stimulation, a recently developed neuromodulation method, can increase motor function in mice with spinal cord injury. This study aimed to explore the possible mechanism by which transcranial magnetic stimulation (TMS) restores motor function after SCI. A complete T8 transection model of the spinal cord was established in mice, and the mice were treated daily with 15 Hz high-frequency transcranial magnetic stimulation. The BMS was used to evaluate the motor function of the mice after SCI. Western blotting and immunofluorescence were used to detect the expression of Connexin43 (CX43) and autophagy-related proteins in vivo and in vitro, and correlation analysis was performed to study the relationships among autophagy, CX43 and motor function recovery after SCI in mice. Western blotting was used to observe the effect of magnetic stimulation on the expression of mTOR pathway members. In the control group, the expression of CX43 was significantly decreased, and the expression of microtubule-associated protein 1 A/1b light chain 3 (LC3II) and P62 was significantly increased after 4 weeks of spinal cord transection. After high-frequency magnetic stimulation, the level of CX43 decreased, and the levels of LC3II and P62 increased in primary astrocytes. The BMS of the magnetic stimulation group was greater than that of the control group. High-frequency magnetic stimulation can inhibit the expression of CX43, which negatively regulates autophagic flux. HF-rTMS increased the expression levels of mTOR, p-mTOR and p-S6. Our experiments showed that rTMS can restore hindlimb motor function in mice after spinal cord injury via regulation of the Cx43-autophagy loop and activation of the mTOR signalling pathway.

Degradation and mechanism of PAHs by Fe-based activated persulfate: Effect of temperature and noble metal.

The accumulation of contaminants like PAHs in soil due to industrialization, urbanization, and intensified agriculture poses environmental challenges, owing to their persistence, hydrophobic nature, and toxicity. Thus, the degradation of PAHs has attracted worldwide attention in soil remediation. This study explored the effect of noble metal and temperature on the degradation of various polycyclic aromatic hydrocarbons (PAHs) in soil, as well as the types of reactive radicals generated and mechanism. The Fe-Pd/AC and Fe-Pt/AC activated persulfate exhibited high removal efficiency of 19 kinds of PAHs, about 79.95 % and 83.36 %, respectively. Fe-Pt/AC-activated persulfate exhibits superior degradation efficiency than that on Fe-Pd/AC-activated persulfate, due to the higher specific surface area and dispersity of Pt particles, thereby resulting in increased reactive radicals (·OH, SO4-· and ·OOH). Additionally, thermal activation enhances the degradation of PAHs, with initial efficiencies of 64.20 % and 55.49 % on Fe-Pd/AC- and Fe-Pt/AC-activated persulfate systems respectively, increasing to 76.05 % and 73.14 % with elevated temperatures from 21.5 to 50 °C. Metal and thermal activation facilitate S2O82- activation, generating reactive radicals, crucial for the degradation of PAHs via ring opening and oxygen hydrogenation reactions, yielding low-ring oxygen-containing derivatives such as organic acids, keto compounds, ethers, and esters. Furthermore, understanding the impact of parameters such as activation temperature and the types of noble metals on the degradation of PAHs within the activated persulfate system provides a theoretical foundation for the remediation of PAH-contaminated soil.

Persulfate-Based Advanced Oxidation Process for Chlorpyrifos Degradation: Mechanism, Kinetics, and Toxicity Assessment.

Persulfate-based advanced oxidation process has been proven to be a promising method for the toxic pesticide chlorpyrifos (CPY) degradation in wastewater treatment. However, due to the limitation for the short-lived intermediates detection, a comprehensive understanding for the degradation pathway remains unclear. To address this issue, density functional theory was used to analyze the degradation mechanism of CPY at the M06-2X/6-311++G(3df,3pd)//M06-2X/6-31+G(d,p) level, and computational toxicology methods were employed to explore the toxicity of CPY and its degradation products. Results show that hydroxyl radicals (·OH) and sulfate radicals (SO4•-) initiate the degradation reactions by adding to the P=S bond and abstracting the H atom on the ethyl group, rather than undergoing α-elimination of the pyridine ring in the persulfate oxidation process. Moreover, the addition products were attracted and degraded by breaking the P-O bond, while the abstraction products were degraded through dealkylation reactions. The transformation products, including 3,5,6-trichloro-2-pyridynol, O,O-diethyl phosphorothioate, chlorpyrifos oxon, and acetaldehyde, obtained through theoretical calculations have been detected in previous experimental studies. The reaction rate constants of CPY with ·OH and SO4•- were 6.32 × 108 and 9.14 × 108 M-1·s-1 at room temperature, respectively, which was consistent with the experimental values of 4.42 × 109 and 4.5 × 109 M-1 s-1. Toxicity evaluation results indicated that the acute and chronic toxicity to aquatic organisms gradually decreased during the degradation process. However, some products still possess toxic or highly toxic levels, which may pose risks to human health. These research findings contribute to understanding the transformation behavior and risk assessment of CPY in practical wastewater treatment.

Disruptions of Gut Microbiota are Associated with Cognitive Deficit of Preclinical Alzheimer's Disease: A Cross-Sectional Study.

BACKGROUND: Alzheimer's Disease (AD) is the most prevalent type of dementia. The early change of gut microbiota is a potential biomarker for preclinical AD patients. OBJECTIVE: The study aimed to explore changes in gut microbiota characteristics in preclinical AD patients, including those with Subjective Cognitive Decline (SCD) and Mild Cognitive Impairment (MCI), and detect the correlation between gut microbiota characteristics and cognitive performances. METHODS: This study included 117 participants [33 MCI, 54 SCD, and 30 Healthy Controls (HC)]. We collected fresh fecal samples and blood samples from all participants and evaluated their cognitive performance. We analyzed the diversity and structure of gut microbiota in all participants through qPCR, screened characteristic microbial species through machine learning models, and explored the correlations between these species and cognitive performances and serum indicators. RESULTS: Compared to the healthy controls, the structure of gut microbiota in MCI and SCD patients was significantly different. The three characteristic microorganisms, including Bacteroides ovatus, Bifidobacterium adolescentis, and Roseburia inulinivorans, were screened based on the best classification model (HC and MCI) having intergroup differences. Bifidobacterium adolescentis is associated with better performance in multiple cognitive scores and several serum indicators. Roseburia inulinivorans showed negative correlations with the scores of the Functional Activities Questionnaire (FAQ). CONCLUSION: The gut microbiota in patients with preclinical AD has significantly changed in terms of composition and richness. Correlations have been discovered between changes in characteristic species and cognitive performances. Gut microbiota alterations have shown promise in affecting AD pathology and cognitive deficit.