Alterations of regional homogeneity in perimenopause: a resting-state functional MRI study.

OBJECTIVE: Regional homogeneity (ReHo) was used to evaluate the changes of brain function and the relationship with cognitive function in perimenopausal women. METHODS：: The cross-sectional study recruited 25 perimenopausal women and 25 postmenopausal women who underwent sex hormone level measurements, clinical and neuropsychological assessments, and magnetic resonance imaging (MRI) scans. ReHo was measured based on the resting-state functional MRI (rs-fMRI) data and the differences in ReHo between the perimenopausal and postmenopausal groups were compared. Gray matter volume (GMV) values of brain regions with differences (region of interest [ROI]) in ReHo were extracted and the differences of GMV between the two groups were compared. We analyzed the correlations of the ReHo and GMV values of these ROIs with the results of sex hormone levels, clinical and neuropsychological assessments in the two groups. RESULTS: ReHo values in the left lingual gyrus and the right precentral gyrus increased in perimenopause, whereas ReHo values in the left inferior temporal gyrus and bilateral putamen decreased. Correlation analysis showed that the ReHo values of the left inferior temporal gyrus positively correlated with the reaction time of the Stroop color word test in perimenopausal women. CONCLUSIONS: Changes in abnormal patterns of the ReHo in perimenopausal women affect cognitive function. These changes in brain function may provide more insights and information on the neural mechanisms of cognitive dysfunction in perimenopausal women.

Symbiotic fungal endophyte Phomopsis liquidambari-rice system promotes nitrogen transformation by influencing below-ground straw decomposition in paddy soil.

AIMS: To explore if and how symbiotic Phomopsis liquidambari-rice system influences below-ground straw decomposition and then nitrogen(N) transformation in response to environmental N levels. METHODS AND RESULTS: Litter bag experiments were utilized to trace the decay process during rice growth phases (seedling (T1), tillering (T2), heading (T3) and maturing (T4) stage), with (E+) and without endophyte (E-), under low (LN), medium (MN) and high nitrogen (HN) supply. Litter, soil and plant samples were collected to evaluate the decay process, N transformations, plant quality and relative abundance of soil ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and P. liquidambari. The results showed that straw decomposition increased by 19·76% (LN, T2 stage), 14·05% (MN, T3 stage) and 16·88% (MN, T4 stage) in E+ pots when compared with E- pots. Further analysis revealed that no significant endophyte × N interaction was found for straw decay rate and that the decay rate was reduced by a higher N supply (LN, 37·16 ± 0·65%; MN, 32·27 ± 1·72%; HN, 29·44 ± 1·22%) at the T1 stage, whereas straw decay rate and N release increased by 9·38 and 11·16%, respectively, mainly by endophyte colonization at the T4 stage. The abundance of AOA and AOB were altered, corresponding with the decay rate. Soil mineral N, straw mineral N and plant quality were shown to increase in E+ pots, depending on environmental N conditions and growth phase. The yield increased by 2·98% for E+ plants under MN level. CONCLUSIONS: Symbiotic P. liquidambari-rice system promoted below-ground straw decomposition and N transformation, depending on environmental N levels and plant growth phase. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides evidence that fungal endophyte-plant systems are able to promote N transformation by increasing straw decomposition. A reasonable combination of N inputs could enhance its advantage in agriculture ecosystems.