Detoxification of aflatoxin B1 in corn by chlorine dioxide gas.

Chlorine dioxide (ClO2) gas was utilized for detoxifying aflatoxin B1 (AFB1) in corn for the first time. Four degradation compounds were identified by LC-MS as C17H13O8, C17H15O10, C16H15O10, and C15H11O8. Structurally, the biological activity of ClO2-treated AFB1 was removed due to the disappearance of C8-C9 double bond in the furan ring and the modification of cyclopentanone and methoxy after ClO2 treatment. The cell viability assay on human embryo hepatocytes confirmed little toxicity of the degradation products. The degradation efficiency of AFB1 on corn peaked near 90.0% under the optimized conditions and reached 79.6% for low initial contamination of AFB1 at 5-20 µg/kg. Accordingly, ClO2 has the potential to be developed into an effective, efficient, and economic approach to detoxify AFB1 in grains.

Male sterile 305 Mutation Leads the Misregulation of Anther Cuticle Formation by Disrupting Lipid Metabolism in Maize.

The anther cuticle, which is mainly composed of lipid polymers, functions as physical barriers to protect genetic material intact; however, the mechanism of lipid biosynthesis in maize (Zea mays. L.) anther remains unclear. Herein, we report a male sterile mutant, male sterile 305 (ms305), in maize. It was shown that the mutant displayed a defective anther tapetum development and premature microspore degradation. Three pathways that are associated with the development of male sterile, including phenylpropanoid biosynthesis, biosynthesis of secondary metabolites, as well as cutin, suberine, and wax biosynthesis, were identified by transcriptome analysis. Gas chromatography-mass spectrometry disclosed that the content of cutin in ms305 anther was significantly lower than that of fertile siblings during the abortion stage, so did the total fatty acids, which indicated that ms305 mutation might lead to blocked synthesis of cutin and fatty acids in anther. Lipidome analysis uncovered that the content of phosphatidylcholine, phosphatidylserine, diacylglycerol, monogalactosyldiacylglycerol, and digalactosyldiacylglycerol in ms305 anther was significantly lower when compared with its fertile siblings, which suggested that ms305 mutation disrupted lipid synthesis. In conclusion, our findings indicated that ms305 might affect anther cuticle and microspore development by regulating the temporal progression of the lipidome in maize.

Theory of mind in Alzheimer's disease and amnestic mild cognitive impairment: a meta-analysis.

BACKGROUND: The assessment of theory of mind (ToM) performance in Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) remains inconclusive. We conducted a meta-analysis to investigate ToM performance in patients with aMCI and AD. METHODS: A systematic literature search was performed for eligible studies published up to July 2019 in three international databases (PubMed, Embase, and Web of Science). Due to heterogeneity between studies, a random-effects model was used. Individual ToM tasks were meta-analyzed separately and possible sources of heterogeneity were examined. RESULTS: In total, 36 studies involving 701 individuals with AD and 197 with aMCI were identified. Compared with healthy controls, ToM was impaired in both AD (d = 1.45) and aMCI patients (d = 0.65). In AD patients, ToM was particularly impaired in advanced tasks such as Faux Pas Recognition (d = 1.26). In patients with aMCI, ToM deficits were relatively modest, with the exception of the reading the mind in the eyes task (d = 1.22). ToM was significantly more impaired in AD than that in aMCI (d = 0.88). CONCLUSIONS: This is the first meta-analysis examining ToM performance in AD and aMCI simultaneously. The results showed that ToM deficits were more severe in AD than that in aMCI in most individual ToM tasks. Longitudinal studies are warranted to determine whether ToM abilities in aMCI patients can be used for prognostic purposes.

Obstructive sleep apnea in Parkinson's disease: a study in 239 Chinese patients.

OBJECTIVE: Our objective was to explore the clinical characteristics of Parkinson's disease (PD) comorbidity with obstructive sleep apnea (OSA), explore the correlation between OSA and PD features and identify factors that are independent predictors of OSA in PD patients. METHODS: In sum, 239 PD patients were divided into two groups according to the presence of OSA (apnea-hypopnea index (AHI) score ≥5) (PD-OSA vs PD-non-OSA). Blinded to sleep apnea status, participants underwent an extensive assessment to determine demographic features, concomitant disease, disease severity, polysomnography (PSG) characteristics and non-motor symptoms (NMSs). RESULTS: Of the 239 patients, 66 (27.62%) had an AHI score ≥5, including 14.2% (34/239) with mild, 6.7% (16/239) with moderate, and 6.7% (16/239) with severe sleep apnea. The binary logistic regression analyses indicated that age and male gender were risk factors for OSA, while rapid eye movement (REM) sleep disorder (RBD) and higher Levodopa equivalent dose (LED) were protective factors for OSA. PD-OSA patients had higher Epworth Sleepiness Scale (ESS) scores than those of PD-non-OSA patients. No differences were found for other NMSs between groups. CONCLUSION: Our data suggest that OSA in PD was lower in patients with RBD and higher LED. RBD and higher LDEs were significant protective factors for OSA in PD. OSA in PD was increased with age and male gender. Age and male gender were risk factors for OSA in PD. OSA can aggravate excessive daytime somnolence in PD patients but is not associated with other NMSs.

Non-structural carbohydrates in maize with different nitrogen tolerance are affected by nitrogen addition.

Non-structural carbohydrates (NSCs) are an important energy source for plant growth and metabolism. Analysis of NSC changes can provide important clues to reveal the adaptation mechanisms of plants to a specific environment. Although considerable differences have been reported in NSCs in response to nitrogen (N) application among crop species and cultivars, previous studies have mostly focused on the differences in leaves and stems. However, the effects of N on the characteristics of accumulation and translocation of NSC in maize with different levels of N tolerance remain unclear. To determine differences in the N levels, two cultivars (N-efficient ZH311 and N-inefficient XY508) were grown in field pots (Experiment I) and as hydroponic cultures (Experiment II) and were supplemented with different concentrations of N fertilizer. In both experiments, low-N stress significantly increased the accumulation of NSCs in maize vegetative organs and increased the translocation rate of NSCs in the stems and their apparent contribution to yield, thereby reducing the yield loss caused by low-N stress. N application had a greater effect on starch content in the vegetative organs of ZH311, but had less effect on soluble sugar (SS) and NSC content in the whole plant and starch content in the ears. ZH311 could convert more starch into SS under low N conditions to adapt to low N environments than XY508, while ensuring that grain yield and starch quantity were not affected. This is evidently an important physiological mechanism involved in this cultivar's tolerance to low N conditions.

Transcriptome analysis reveals the molecular mechanisms of the defense response to gray leaf spot disease in maize.

BACKGROUND: Gray leaf spot (GLS), which is caused by the necrotrophic fungi Cercospora zeae-maydis and Cercospora zeina, is one of the most impactful diseases in maize worldwide. The aim of the present study is to identify the resistance genes and understand the molecular mechanisms for GLS resistance. RESULTS: Two cultivars, 'Yayu889' and 'Zhenghong532,' which are distinguished as resistant and susceptible cultivars, respectively, were challenged with the GLS disease and a RNA-seq experiment was conducted on infected plants at 81, 89, 91, and 93 days post planting (dap). Compared with the beginning stage at 81 dap, 4666, 1733, and 1166 differentially expressed genes (DEGs) were identified at 89, 91, and 93 dap, respectively, in 'Yayu889,' while relatively fewer, i.e., 4713, 881, and 722 DEGs, were identified in 'Zhenghong532.' Multiple pathways involved in the response of maize to GLS, including 'response to salicylic acid,' 'protein phosphorylation,' 'oxidation-reduction process,' and 'carotenoid biosynthetic process,' were enriched by combining differential expression analysis and Weighted Gene Co-expression Network Analysis (WGCNA). The expression of 12 candidate resistance proteins in these pathways were quantified by the multiple reaction monitoring (MRM) method. This approach identified two candidate resistance proteins, a calmodulin-like protein and a leucine-rich repeat receptor-like protein kinase with SNPs that were located in QTL regions for GLS resistance. Metabolic analysis showed that, compared with 'Zhenghong532,' the amount of salicylic acid (SA) and total carotenoids in 'Yayu889' increased, while peroxidase activity decreased during the early infection stages, suggesting that increased levels of SA, carotenoids, and reactive oxygen species (ROS) may enhance the defense response of 'Yayu889' to GLS. CONCLUSION: By combining transcriptome and proteome analyses with comparisons of resistance QTL regions, calmodulin-like protein and leucine-rich repeat receptor-like protein kinase were identified as candidate GLS resistance proteins. Moreover, we found that the metabolic pathways for ROS, SA, and carotenoids are especially active in the resistant cultivar. These findings could lead to a better understanding of the GLS resistance mechanisms and facilitate the breeding of GLS-resistant maize cultivars.

Cultivar Differences in Root Nitrogen Uptake Ability of Maize Hybrids.

Although, considerable differences in root size in response to nitrogen (N) application among crop species and cultivars have been widely reported, there has been limited focus on the differences in root N uptake ability. In this study, two maize (Zea mays L.) hybrids, Zhenghong 311 (ZH 311, N-efficient) and Xianyu 508 (XY 508, N-inefficient), were used to compare differences in root N uptake ability. The two cultivars were grown in field pots Experiment I (Exp. I) and hydroponic cultures Experiment II (Exp. II) supplemented with different concentrations of N fertilizer. In both experiments, the levels of accumulated N were higher in ZH 311 than in XY 508 under low- and high-N supply, and the increment in accumulated N was greater under N deficiency. The maximum N uptake rate (Vm) and average N uptake rate (Va) in Exp. I, the root N kinetic parameter maximum uptake rate (Vmax) per fresh weight (FW) and Vmax per plant in Exp. II, and the root N uptake rate in both experiments were significantly higher for ZH 311 than for XY 508. In contrast, the root-to-shoot N ratio in both experiments and the root N kinetic parameter Michaelis constant (Km) in in Exp. II were markedly higher in XY 508 than in ZH 311, particularly under N-deficient conditions. Higher root N kinetic parameters Vmax per FW and Vmax per plant and lower Km values contributed to higher N affinity and uptake potential, more coordinated N distribution in the root and shoot, and higher root N uptake rates throughout the growth stages, thus enhancing the N accumulation and yield of the N-efficient maize cultivar. We conclude that the N uptake ability of roots in the N-efficient cultivar ZH 311 is significantly greater than that in the N-inefficient cultivar XY 508, and that this advantage is more pronounced under N-deficient conditions. The efficient N acquisition in ZH 311 is due to higher N uptake rate per root FW under optimal N conditions and the comprehensive effects of root size and N uptake rate per root FW under N deficiency.

Voxelwise meta-analysis of gray matter anomalies in Alzheimer's disease and mild cognitive impairment using anatomic likelihood estimation.

BACKGROUND: Many voxel-based morphometry studies in Alzheimer's disease (AD) and mild cognitive impairment (MCI) yielded not entirely consistent results. We conducted meta-analyses of gray matter anomalies to identify robust neuroanatomical changes between them. METHODS: A systematic review of voxel-based morphometry studies of patients with AD and MCI relative to healthy comparison subjects in PubMed, Embase databases from January 1995 to 29 April, 2011 was conducted. The anatomical distribution of the coordinates of gray matter differences was meta-analyzed using anatomical likelihood estimation (ALE). Separate maps of gray matter changes were constructed, and subtraction meta-analysis between AD and MCI was also performed. RESULTS: Thirty-five AD studies and twenty-four MCI studies were included in the meta-analysis. Extensive gray matter deficits were present in the medial temporal lobe (including entorhinal cortex, hippocampus, parahippocampus, amygdala and uncus), thalamus, temporal, parietal, frontal and cingulate and insular cortices in AD. In MCI, gray matter reductions were identified in the medial temporal lobe (including entorhinal cortex, hippocampus, parahippocampus, amygdala and uncus), temporal, thalamus, and cingulate cortex. Subtraction meta-analysis found more severe gray matter deficit mainly in the left medial lobe (including parahippocampus, amygdala and hippocampus). CONCLUSIONS: Our meta-analysis identified similar distributions of neuroanatomical changes in AD and MCI, which are consistent with the hierarchical model of neuropathological alterations of neurofibrillary tangles in AD and MCI. Subtraction analysis provided evidence that the left MTL may be a neuroanatomical marker to evaluate disease progression from MCI to AD.