ABSTRACT
Microplastics (MPs), which are widely present in the natural environment, may be harmful to the growth and health of aquatic organisms, though studies in this area are lacking. In this study, the crucian carp (Carassius carassius), a type of omnivorous freshwater fish, was chosen as the target, which was fed with fish food containing different concentrations of MPs for a 30-day food exposure experiment to study the effects of MPs on crucian growth, liver damage, and gut microbiome composition. Compared with that in the control group, the body length of the crucians in the environmental groups did not change significantly. The weight of the crucians in the low PE-MPs group increased significantly, but the weight of crucians in the medium and high PE-MPs groups decreased markedly. The liver tissues of the low PE-MPs group of crucians were basically normal, whereas crucians in the medium and high PE-MPs groups had varying degrees of liver damage, and crucians in the high PE-MPs group had the most serious liver damage. At the phylum level, Proteobacteria, Fusobacteria, Firmicutes, and Bacteroides were the dominant species in the gut of the crucians. Pathogens such as Staphylococcus and Ralstonia were present in the crucian gut of environmental groups. Alpha diversity results showed that the gut microbiome of crucians in the high PE-MPs group was the most abundant. PCoA results indicated that the gut microbiome of crucians in the control and environmental groups had obvious clustering characteristics.
Subject(s)
Gastrointestinal Microbiome , Microplastics , Animals , Firmicutes , Liver , PlasticsABSTRACT
Alterations in default mode network (DMN) functional connectivity (FC) might accompany the dysfunction of Alzheimer's disease (AD). Indeed, episodic memory impairment is a hallmark of AD, and mild cognitive impairment (MCI) has been associated with a high risk for AD. Phosphatidylinositol-binding clathrin assembly protein (PICALM) (rs3851179) has been associated with AD; in particular, the A allele may serve a protective role, while the G allele serves as a strong genetic risk factor. Therefore, the identification of genetic polymorphisms associated with the DMN is required in MCI subjects. In all, 32 MCI subjects and 32 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging (rs-fMRI) and a genetic imaging approach. Subjects were divided into four groups according to the diagnosis (i.e., MCI and HCs) and the PICALM rs3851179 polymorphism (i.e., AA/AG genotype and GG genotype). The differences in FC within the DMN between the four subgroups were explored. Furthermore, we examined the relationship between our neuroimaging measures and cognitive performance. The regions associated with the genotype-by-disease interaction were in the left middle temporal gyrus (LMTG) and left middle frontal gyrus (LMFG). These changes in LMFG FC were generally manifested as an "inverse U-shaped curve", while a "U-shaped curve" was associated with the LMTG FC between these four subgroups (all P<0.05). Furthermore, higher FC within the LMFG was related to better episodic memory performance (i.e., AVLT 20min DR, rho=0.72, P=0.044) for the MCI subgroups with the GG genotype. The PICALM rs3851179 polymorphism significantly affects the DMN network in MCI. The LMFG and LMTG may be associated with opposite patterns. However, the altered LMFG FC in MCI patients with the GG genotype was more sensitive to episodic memory impairment, which is more likely to lead to a high risk of AD.
