Transformer-based deep learning denoising of single and multi-delay 3D arterial spin labeling.

PURPOSE: To present a Swin Transformer-based deep learning (DL) model (SwinIR) for denoising single-delay and multi-delay 3D arterial spin labeling (ASL) and compare its performance with convolutional neural network (CNN) and other Transformer-based methods. METHODS: SwinIR and CNN-based spatial denoising models were developed for single-delay ASL. The models were trained on 66 subjects (119 scans) and tested on 39 subjects (44 scans) from three different vendors. Spatiotemporal denoising models were developed using another dataset (6 subjects, 10 scans) of multi-delay ASL. A range of input conditions was tested for denoising single and multi-delay ASL, respectively. The performance was evaluated using similarity metrics, spatial SNR and quantification accuracy of cerebral blood flow (CBF), and arterial transit time (ATT). RESULTS: SwinIR outperformed CNN and other Transformer-based networks, whereas pseudo-3D models performed better than 2D models for denoising single-delay ASL. The similarity metrics and image quality (SNR) improved with more slices in pseudo-3D models and further improved when using M0 as input, but introduced greater biases for CBF quantification. Pseudo-3D models with three slices achieved optimal balance between SNR and accuracy, which can be generalized to different vendors. For multi-delay ASL, spatiotemporal denoising models had better performance than spatial-only models with reduced biases in fitted CBF and ATT maps. CONCLUSIONS: SwinIR provided better performance than CNN and other Transformer-based methods for denoising both single and multi-delay 3D ASL data. The proposed model offers flexibility to improve image quality and/or reduce scan time for 3D ASL to facilitate its clinical use.

ASL lexicon and reporting recommendations: A consensus report from the ISMRM Open Science Initiative for Perfusion Imaging (OSIPI).

The 2015 consensus statement published by the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group and the European Cooperation in Science and Technology ( COST) Action ASL in Dementia aimed to encourage the implementation of robust arterial spin labeling (ASL) perfusion MRI for clinical applications and promote consistency across scanner types, sites, and studies. Subsequently, the recommended 3D pseudo-continuous ASL sequence has been implemented by most major MRI manufacturers. However, ASL remains a rapidly and widely developing field, leading inevitably to further divergence of the technique and its associated terminology, which could cause confusion and hamper research reproducibility. On behalf of the ISMRM Perfusion Study Group, and as part of the ISMRM Open Science Initiative for Perfusion Imaging (OSIPI), the ASL Lexicon Task Force has been working on the development of an ASL Lexicon and Reporting Recommendations for perfusion imaging and analysis, aiming to (1) develop standardized, consensus nomenclature and terminology for the broad range of ASL imaging techniques and parameters, as well as for the physiological constants required for quantitative analysis; and (2) provide a community-endorsed recommendation of the imaging parameters that we encourage authors to include when describing ASL methods in scientific reports/papers. In this paper, the sequences and parameters in (pseudo-)continuous ASL, pulsed ASL, velocity-selective ASL, and multi-timepoint ASL for brain perfusion imaging are included. However, the content of the lexicon is not intended to be limited to these techniques, and this paper provides the foundation for a growing online inventory that will be extended by the community as further methods and improvements are developed and established.

Decreased water exchange rate across blood-brain barrier in hereditary cerebral small vessel disease.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and heterozygous HTRA1 mutation-related cerebral small vessel disease (CSVD) are the two types of dominant hereditary CSVD. Blood-brain barrier (BBB) failure has been hypothesized in the pathophysiology of CSVD. However, it is unclear whether there is BBB damage in the two types of hereditary CSVD, especially in heterozygous HTRA1 mutation-related CSVD. In this study, a case-control design was used with two disease groups including CADASIL (n = 24), heterozygous HTRA1 mutation-related CSVD (n = 9) and healthy controls (n = 24). All participants underwent clinical cognitive assessments and brain MRI. Diffusion-prepared pseudo-continuous arterial spin labelling was used to estimate the water exchange rate across the BBB (kw). Correlation and multiple linear regression analyses were used to examine the association between kw and disease burden and neuropsychological performance, respectively. Compared with the healthy controls, kw in the whole brain and multiple brain regions was decreased in both CADASIL and heterozygous HTRA1 mutation-related CSVD patients (Bonferroni-corrected P < 0.007). In the CADASIL group, decreased kw in the whole brain (ß = -0.634, P = 0.001), normal-appearing white matter (ß = -0.599, P = 0.002) and temporal lobe (ß = -0.654, P = 0.001) was significantly associated with higher CSVD score after adjusting for age and sex. Reduced kw in the whole brain was significantly associated with poorer neuropsychological performance after adjusting for age, sex and education in both CADASIL and heterozygous HTRA1 mutation-related CSVD groups (ß = 0.458, P = 0.001; ß = 0.884, P = 0.008). This study showed that there was decreased water exchange rate across the BBB in both CADASIL and heterozygous HTRA1 mutation-related CSVD patients, suggesting a common pathophysiological mechanism underlying the two types of hereditary CSVD. These results highlight the potential use of kw for monitoring the course of CADASIL and heterozygous HTRA1 mutation-related CSVD, a possibility which should be tested in future research.

Transcriptome analysis reveals the mechanism of antifungal peptide epinecidin-1 against Botrytis cinerea by mitochondrial dysfunction and oxidative stress.

The marine antifungal peptide epinecidin-1 (EPI) have been shown to inhibit Botrytis cinerea growth, while the molecular mechanism have not been explored based on omics technology. This study aimed to investigate the molecular mechanism of EPI against B. cinerea by transcriptome technology. Our findings indicated that a total of 1671 differentially expressed genes (DEGs) were detected in the mycelium of B. cinerea treated with 12.5 µmol/L EPI for 3 h, including 773 up-regulated genes and 898 down-regulated genes. Cluster analysis showed that DEGs (including steroid biosynthesis, (unsaturated) fatty acid biosynthesis) related to cell membrane metabolism were significantly down-regulated, and almost all DEGs involved in DNA replication were significantly inhibited. In addition, it also induced the activation of stress-related pathways, such as the antioxidant system, ATP-binding cassette transporter (ABC) and MAPK signaling pathways, and interfered with the tricarboxylic acid (TCA) cycle and oxidative phosphorylation pathways related to mitochondrial function. The decrease of mitochondrial related enzyme activities (succinate dehydrogenase, malate dehydrogenase and adenosine triphosphatase), the decrease of mitochondrial membrane potential and the increase content of hydrogen peroxide further confirmed that EPI treatment may lead to mitochondrial dysfunction and oxidative stress. Based on this, we speculated that EPI may impede the growth of B. cinerea through its influence on gene expression, and may lead to mitochondrial dysfunction and oxidative stress.

Heterogeneous blood-brain barrier dysfunction in cerebral small vessel diseases.

INTRODUCTION: We explored how blood-brain barrier (BBB) leakage rate of gadolinium chelates (Ktrans) and BBB water exchange rate (kw) varied in cerebral small vessel disease (cSVD) subtypes. METHODS: Thirty sporadic cSVD, 40 cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and 13 high-temperature requirement factor A serine peptidase 1 (HTRA) -related cSVD subjects were investigated parallel to 40 healthy individuals. Subjects underwent clinical, cognitive, and MRI assessment. RESULTS: In CADASIL, no difference in Ktrans, but lower kw was observed in multiple brain regions. In sporadic cSVD, no difference in kw, but higher Ktrans was found in the whole brain and normal-appearing white matter. In HTRA1-related cSVD, both higher Ktrans in the whole brain and lower kw in multiple brain regions were observed. In each patient group, the altered BBB measures were correlated with lesion burden or clinical severity. DISCUSSION: In cSVD subtypes, distinct alterations of kw and Ktrans were observed. The combination of Ktrans and kw can depict the heterogeneous BBB dysfunction. HIGHLIGHTS: We measured BBB leakage to gadolinium-based contrast agent (Ktrans) and water exchange rate (kw) across BBB in three subtypes of cSVD. CADASIL is characterized by lower kw, HTRA1-related cSVD exhibits both higher Ktrans and lower kw, while sporadic cSVD is distinguished by higher Ktrans. There are distinct alterations in kw and Ktrans among subtypes of cSVD, indicating the heterogeneous nature of BBB dysfunction.

Acid-induced conformation regulation of peanut polysaccharide and its effect on stability and digestibility of oil-in-water emulsion.

BACKGROUND: Developing the stable and healthy emulsion-based food is in accord with the needs of people for health. In the present study, acidification at pH 3.0 of peanut polysaccharide (APPSI) was employed to regulate its conformation and further improve its advantages in preparing oil-in-water emulsion. RESULTS: The results indicated that acidification induced conversion of PPSI aggregates into linear chains. Increasing concentration promoted formation of cross-linked network structure shown in transmission electron microscopy images. Consequently, the viscosity, yield stress, storage modulus and flow activation energy significantly increased, further fabricating gel structure. Moreover, aggregation behavior suggested that more exposed proteins were involved in gel structure, thereby forming many hydrophobic cores as verified by fluorescence spectroscopy of pyrene. Afterwards, emulsion characteristics indicated that APPSI produced strong and thick steric hindrance around oil droplets and the coil-like interweaved chains locked the continuous phase, bringing strong elasticity and resistance to stress and creaming. Meanwhile, the lower fatty acid in APPSI-emulsion was released after simulated gastrointestinal digestion, mainly as a result of the high retention ratio of emulsion droplets. Furthermore, the elastic and viscous Lissajous curves suggested that the structure strength of APPSI-emulsion was similar to that of the salad dressing within the strain 53.22%. CONCLUSION: The conformation of PPSI after acidification at pH 3.0 was suitable for preparing the stable emulsion. The obtained emulsion could resist digestion and maintain a strong structure, comprising a cholesterol-free and low-fat salad dressing substitute. © 2023 Society of Chemical Industry.

Influence of flavonoids from Sedum aizoon L. on mitochondrial function of Rhizopus nigricans in strawberry.

Rhizopus nigricans (R. nigricans), one of the fungi that grows the fastest, is frequently discovered in postharvest fruits, it's the main pathogen of strawberry root rot. Flavonoids in Sedum aizoon L. (FSAL) is a kind of green and safe natural substance extracted from Sedum aizoon L. which has antifungal activity. In this study, the minimum inhibitory concentration (MIC) of FSAL on R. nigricans and cell apoptosis tests were studied to explore the inhibitory effect of FSAL on R. nigricans. The effects of FSAL on mitochondria of R. nigricans were investigated through the changes of mitochondrial permeability transition pore(mPTP), mitochondrial membrane potential(MMP), Ca2+ content, H2O2 content, cytochrome c (Cyt c) content, the related enzyme activity and related genes of mitochondria. The results showed that the MIC of FSAL on R. nigricans was 1.800 mg/mL, with the addition of FSAL (1.800 mg/mL), the mPTP openness of R. nigricans increased and the MMP reduced. Resulting in an increase in Ca2+ content, accumulation of H2O2 content and decrease of Cyt c content, the activity of related enzymes was inhibited and related genes were up-regulated (VDAC1, ANT) or down-regulated (SDHA, NOX2). This suggests that FSAL may achieve the inhibitory effect of fungi by damaging mitochondria, thereby realizing the postharvest freshness preservation of strawberries. This lays the foundation for the development of a new plant-derived antimicrobial agent.

Whole-Cerebrum distortion-free three-dimensional pseudo-continuous arterial spin labeling at 7T.

Fulfilling potentials of ultrahigh field for pseudo-Continuous Arterial Spin Labeling (pCASL) has been hampered by B1/B0 inhomogeneities that affect pCASL labeling, background suppression (BS), and the readout sequence. This study aimed to present a whole-cerebrum distortion-free three-dimensional (3D) pCASL sequence at 7T by optimizing pCASL labeling parameters, BS pulses, and an accelerated Turbo-FLASH (TFL) readout. A new set of pCASL labeling parameters (Gave = 0.4 mT/m, Gratio = 14.67) was proposed to avoid interferences in bottom slices while achieving robust labeling efficiency (LE). An OPTIM BS pulse was designed based on the range of B1/B0 inhomogeneities at 7T. A 3D TFL readout with 2D-CAIPIRINHA undersampling (R = 2 × 2) and centric ordering was developed, and the number of segments (Nseg) and flip angle (FA) were varied in simulation to achieve the optimal trade-off between SNR and spatial blurring. In-vivo experiments were performed on 19 subjects. The results showed that the new set of labeling parameters effectively achieved whole-cerebrum coverage by eliminating interferences in bottom slices while maintaining a high LE. The OPTIM BS pulse achieved 33.3% higher perfusion signal in gray matter (GM) than the original BS pulse with a cost of 4.8-fold SAR. Incorporating a moderate FA (8°) and Nseg (2), whole-cerebrum 3D TFL-pCASL imaging was achieved with a 2 × 2 × 4 mm3 resolution without distortion and susceptibility artifacts compared to 3D GRASE-pCASL. In addition, 3D TFL-pCASL showed a good to excellent test-retest repeatability and potential of higher resolution (2 mm isotropic). The proposed technique also significantly improved SNR when compared to the same sequence at 3T and simultaneous multislice TFL-pCASL at 7T. By combining a new set of labeling parameters, OPTIM BS pulse, and accelerated 3D TFL readout, we achieved high resolution pCASL at 7T with whole-cerebrum coverage, detailed perfusion and anatomical information without distortion, and sufficient SNR.

Quantification of blood-brain barrier water exchange and permeability with multidelay diffusion-weighted pseudo-continuous arterial spin labeling.

PURPOSE: To present a pulse sequence and mathematical models for quantification of blood-brain barrier water exchange and permeability. METHODS: Motion-compensated diffusion-weighted (MCDW) gradient-and-spin echo (GRASE) pseudo-continuous arterial spin labeling (pCASL) sequence was proposed to acquire intravascular/extravascular perfusion signals from five postlabeling delays (PLDs, 1590-2790 ms). Experiments were performed on 11 healthy subjects at 3 T. A comprehensive set of perfusion and permeability parameters including cerebral blood flow (CBF), capillary transit time (τc ), and water exchange rate (kw ) were quantified, and permeability surface area product (PSw ), total extraction fraction (Ew ), and capillary volume (Vc ) were derived simultaneously by a three-compartment single-pass approximation (SPA) model on group-averaged data. With information (i.e., Vc and τc ) obtained from three-compartment SPA modeling, a simplified linear regression of logarithm (LRL) approach was proposed for individual kw quantification, and Ew and PSw can be estimated from long PLD (2490/2790 ms) signals. MCDW-pCASL was compared with a previously developed diffusion-prepared (DP) pCASL sequence, which calculates kw by a two-compartment SPA model from PLD = 1800 ms signals, to evaluate the improvements. RESULTS: Using three-compartment SPA modeling, group-averaged CBF = 51.5/36.8 ml/100 g/min, kw = 126.3/106.7 min-1 , PSw = 151.6/93.8 ml/100 g/min, Ew = 94.7/92.2%, τc = 1409.2/1431.8 ms, and Vc = 1.2/0.9 ml/100 g in gray/white matter, respectively. Temporal SNR of MCDW-pCASL perfusion signals increased 3-fold, and individual kw maps calculated by the LRL method achieved higher spatial resolution (3.5 mm3 isotropic) as compared with DP pCASL (3.5 × 3.5 × 8 mm3 ). CONCLUSION: MCDW-pCASL allows visualization of intravascular/extravascular ASL signals across multiple PLDs. The three-compartment SPA model provides a comprehensive measurement of blood-brain barrier water dynamics from group-averaged data, and a simplified LRL method was proposed for individual kw quantification.

Update on state-of-the-art for arterial spin labeling (ASL) human perfusion imaging outside of the brain.

This review article provides an overview of developments for arterial spin labeling (ASL) perfusion imaging in the body (i.e., outside of the brain). It is part of a series of review/recommendation papers from the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group. In this review, we focus on specific challenges and developments tailored for ASL in a variety of body locations. After presenting common challenges, organ-specific reviews of challenges and developments are presented, including kidneys, lungs, heart (myocardium), placenta, eye (retina), liver, pancreas, and muscle, which are regions that have seen the most developments outside of the brain. Summaries and recommendations of acquisition parameters (when appropriate) are provided for each organ. We then explore the possibilities for wider adoption of body ASL based on large standardization efforts, as well as the potential opportunities based on recent advances in high/low-field systems and machine-learning. This review seeks to provide an overview of the current state-of-the-art of ASL for applications in the body, highlighting ongoing challenges and solutions that aim to enable more widespread use of the technique in clinical practice.

Diffusion prepared pseudo-continuous arterial spin labeling reveals blood-brain barrier dysfunction in patients with CADASIL.

OBJECTIVES: Diffusion prepared pseudo-continuous arterial spin labeling (DP-pCASL) is a newly proposed MRI method to noninvasively measure the function of the blood-brain barrier (BBB). We aim to investigate whether the water exchange rate across the BBB, estimated with DP-pCASL, is changed in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and to analyze the association between the BBB water exchange rate and MRI/clinical features of these patients. METHODS: Forty-one patients with CADASIL and thirty-six age- and sex-matched controls were scanned with DP-pCASL MRI to estimate the BBB water exchange rate (kw). The MRI lesion burden, the modified Rankin scale (mRS), and the neuropsychological scales were also examined. The association between kw and MRI/clinical features was analyzed. RESULTS: Compared with that in the controls, kw in patients with CADASIL was decreased at normal-appearing white matter (NAWM) (t = - 4.742, p < 0.001), cortical gray matter (t = - 5.137, p < 0.001), and deep gray matter (t = - 3.552, p = 0.001). After adjustment for age, gender, and arterial transit time, kw at NAWM was negatively associated with the volume of white matter hyperintensities (ß = - 0.754, p = 0.001), whereas decreased kw at NAWM was independently associated with an increased risk of abnormal mRS scale (OR = 1.058, 95% CI: 1.013-1.106, p = 0.011) in these patients. CONCLUSIONS: This study found that the BBB water exchange rate was decreased in patients with CADASIL. The decreased BBB water exchange rate was associated with an increased MRI lesion burden and functional dependence of the patients, suggesting the involvement of BBB dysfunction in the pathogenesis of CADASIL. CLINICAL RELEVANCE STATEMENT: DP-pCASL reveals BBB dysfunction in patients with CADASIL. The decreased BBB water exchange rate is associated with MRI lesion burden and functional dependence, indicating the potential of DP-pCASL as an evaluation method for disease severity. KEY POINTS: • DP-pCASL reveals blood-brain barrier dysfunction in patients with CADASIL. • Decreased BBB water exchange rate, an indicator of BBB dysfunction detected by DP-pCASL, was associated with MRI/clinical features of patients with CADASIL. • DP-pCASL can be used as an evaluation method to assess the severity of disease in patients with CADASIL.

Influences of flavonoids from Sedum aizoon L. on biofilm formation of Pseudomonas fragi.

Pseudomonas fragi (P. fragi) is one of the main categories of bacteria responsible for the spoilage of chilled meat. In the processing and preservation of chilled meat, it is easy to form biofilms on the meat, leading to the development of slime on the meat, which becomes a major quality defect. Flavonoids, as one of the critical components of secondary plant metabolites, are receiving increasing attention for their antibacterial activity. Flavonoids in Sedum aizoon L. (FSAL), relying on its prominent antibacterial activity, are of research importance in food preservation and other applications. This article aims to investigate the effect of FSAL on the biofilm formation of P. fragi, to better apply FSAL to the processing and preservation of meat products. The disruption of cellular structure and aggregation properties by FSAL was demonstrated by the observation of the cellular state within the biofilm. The amount of biofilm formation was determined by crystal violet staining, and the content of polysaccharides and proteins in the extracellular wrapped material was determined. It was shown that the experimental concentrations of FSAL (1.0 MIC) was able to inhibit biofilm formation and reduce the main components in the extracellular secretion. The swimming motility assay and the downregulation of flagellin-related genes confirmed that FSAL reduced cell motility and adhesion. The downregulation of cell division genes and the lowering of bacterial metabolic activity suggested that FSAL could hinder bacterial growth and reproduction within P. fragi biofilms. KEY POINTS: • FSAL inhibited the activity of Pseudomonas fragi in the dominant meat strain • The absence of EPS components affected the formation of P. fragi biofilms • P. fragi has reduced adhesion capacity due to impaired flagellin function.

Inhibitory Mechanism of Flavonoids from Sedum aizoon L. on Rhizopus nigricans.

Rhizopus nigricans is a widespread phytopathogen in fruits and vegetables that can cause considerable economic effects and resource waste. Flavonoids from Sedum aizoon L. (FSAL) have specific antifungal activities. This study selected FSAL as an antifungal to prolong the preservation of fruits and vegetables. The results showed that the mycelial morphology and ultrastructure were damaged by the FSAL treatment (1.0 minimum inhibitory concentration), led to the increase of reactive oxygen species and malondialdehyde, and affected the activity of key enzymes in the glycolytic pathway, such as lactic dehydrogenase, pyruvate kinase, and hexokinase of R. nigricans. Key genes in glycolysis were upregulated or downregulated. In addition, in the treatment and control groups, 221 differentially expressed genes were found, including 89 that were upregulated and 32 that were downregulated, according to the transcriptome results. The differential genes were mainly enriched in glycolysis, pyruvate metabolism, and citrate cycle pathways. The results revealed some insights into the antifungal mechanism of FSAL against R. nigricans and offered a theoretical foundation for its advancement as a novel plant-derived antifungal agent.

Isomerization and Stabilization of Amygdalin from Peach Kernels.

In this study, isomerization conditions, cytotoxic activity, and stabilization of amygdalin from peach kernels were analyzed. Temperatures greater than 40 °C and pHs above 9.0 resulted in a quickly increasing isomer ratio (L-amygdalin/D-amygdalin). At acidic pHs, isomerization was significantly inhibited, even at high temperature. Ethanol inhibited isomerization; the isomer rate decreased with the ethanol concentration increasing. The growth-inhibitory effect on HepG2 cells of D-amygdalin was diminished as the isomer ratio increased, indicating that isomerization reduces the pharmacological activity of D-amygdalin. Extracting amygdalin from peach kernels by ultrasonic power at 432 W and 40 °C in 80% ethanol resulted in a 1.76% yield of amygdalin with a 0.04 isomer ratio. Hydrogel beads prepared by 2% sodium alginate successfully encapsulated the amygdalin, and its encapsulation efficiency and drug loading rate reached 85.93% and 19.21%, respectively. The thermal stability of amygdalin encapsulated in hydrogel beads was significantly improved and reached a slow-release effect in in vitro digestion. This study provides guidance for the processing and storage of amygdalin.

Older adults with perivascular spaces exhibit cerebrovascular reactivity deficits.

BACKGROUND: Perivascular spaces on brain magnetic resonance imaging (MRI) may indicate poor fluid drainage in the brain and have been associated with numerous neurological conditions. Cerebrovascular reactivity (CVR) is a marker of cerebrovascular function and represents the ability of cerebral blood vessels to regulate cerebral blood flow in response to vasodilatory or vasoconstrictive stimuli. We aimed to examine whether pathological widening of the perivascular space in older adults may be associated with deficits in CVR. METHODS: Independently living older adults free of dementia or clinical stroke were recruited from the community and underwent brain MRI. Pseudo-continuous arterial spin labeling MRI quantified whole brain cerebral perfusion at rest and during CVR to hypercapnia and hypocapnia induced by visually guided breathing exercises. Perivascular spaces were visually scored using existing scales. RESULTS: Thirty-seven independently living older adults (mean age = 66.3 years; SD = 6.8; age range 55-84 years; 29.7% male) were included in the current analysis. Multiple linear regression analysis revealed a significant negative association between burden of perivascular spaces and global CVR to hypercapnia (B = -2.0, 95% CI (-3.6, -0.4), p = .015), adjusting for age and sex. Perivascular spaces were not related to CVR to hypocapnia. DISCUSSION: Perivascular spaces are associated with deficits in cerebrovascular vasodilatory response, but not vasoconstrictive response. Enlargement of perivascular spaces could contribute to, or be influenced by, deficits in CVR. Additional longitudinal studies are warranted to improve our understanding of the relationship between cerebrovascular function and perivascular space enlargement.

Optimization of pseudo-continuous arterial spin labeling at 7T with parallel transmission B1 shimming.

PURPOSE: To optimize pseudo-continuous arterial spin labeling (pCASL) for 7 T, and to further improve the labeling efficiency with parallel RF transmission transmit B1 ( B1+ ) shimming. METHODS: pCASL parameters were optimized based on B1+/B0 field distributions at 7 T with simulation. To increase labeling efficiency, the B1+ amplitude at inflowing arteries was increased with parallel RF transmission B1+ shimming. The "indv-shim" with shimming weights calculated for each individual subject, and the "univ-shim" with universal weights calculated on a group of 12 subjects, were compared with circular polarized (CP) shim. The optimized pCASL sequences with three B1+ shimming modes (indv-shim, univ-shim, and CP-shim) were evaluated in 6 subjects who underwent two repeated scans 24 hours apart, along with a pulsed ASL sequence. Quantitative metrics including mean B1+ amplitude, perfusion, and intraclass correlation coefficient were calculated. The optimized 7T pCASL was compared with standard 3T pCASL on 5 subjects, using spatial SNR and temporal SNR. RESULTS: The optimal pCASL parameter set (RF duration/gap = 300/250 us, Gave=0.6mT/m,gRatio=10 ) achieved robust perfusion measurement in the presence of B1+/B0 inhomogeneities. Both indv-shim and univ-shim significantly increased B1+ amplitude compared with CP-shim in simulation and in vivo experiment (P < .01). Compared with CP-shim, perfusion signal was increased by 9.5% with indv-shim (P < .05) and by 5.3% with univ-shim (P = .35). All three pCASL sequences achieved fair to good repeatability (intraclass correlation coefficient ≥ 0.5). Compared with 3T pCASL, the optimized 7T pCASL achieved 78.3% higher spatial SNR and 200% higher temporal SNR. CONCLUSION: The optimized pCASL achieved robust perfusion imaging at 7 T, while both indv-shim and univ-shim further increased labeling efficiency.

Jasmonate regulates the FAMA/mediator complex subunit 8-THIOGLUCOSIDE GLUCOHYDROLASE 1 cascade and myrosinase activity.

Myrosinases are ß-thioglucoside glucosidases that are unique to the Brassicales order. These enzymes hydrolyze glucosinolates to produce compounds that have direct antibiotic effects or that function as signaling molecules in the plant immune system, protecting plants from pathogens and insect pests. However, the effects of jasmonic acid (JA), a plant hormone that is crucial for plant disease resistance, on myrosinase activity remain unclear. Here, we systematically studied the effects of JA on myrosinase activity and explored the associated internal transcriptional regulation mechanisms. Exogenous application of JA significantly increased myrosinase activity, while the inhibition of endogenous JA biosynthesis and signaling reduced myrosinase activity. In addition, some myrosinase genes in Arabidopsis (Arabidopsis thaliana) were upregulated by JA. Further genetic and biochemical evidence showed that transcription factor FAMA interacted with a series of JASMONATE ZIM-DOMAIN proteins and affected JA-mediated myrosinase activity. However, among the JA-upregulated myrosinase genes, only THIOGLUCOSIDE GLUCOHYDROLASE 1 (TGG1) was positively regulated by FAMA. Further biochemical analysis showed that FAMA bound to the TGG1 promoter to directly mediate TGG1 expression in conjunction with Mediator complex subunit 8 (MED8). Together, our results provide evidence that JA acts as an important signal upstream of the FAMA/MED8-TGG1 pathway to positively regulate myrosinase activity in Arabidopsis.

Flavonoids from Sedum aizoon L. inhibit Botrytis cinerea by negatively affecting cell membrane lipid metabolism.

Botrytis cinerea is a highly destructive and widespread phytopathogen in fruits. The widespread use of chemical antifungal agents on fruits has aided in disease control while their long-term use has resulted in the emergence of resistant fungal strains. Flavonoids have a specific antifungal effect. The inhibitory effect and underlying mechanism of flavonoids from Sedum aizoon L. (FSAL) on B. cinerea were determined in this study. The results showed that the minimum inhibitory concentration of FSAL against B. cinerea was 1.500 mg/mL. FSAL treatment caused leakage of macromolecules such as nucleic acids, led to accumulation of malondialdehyde and relative oxygen species, and disrupted the ultrastructure of B. cinerea. The transcriptome results indicated that compared with the control group, there were 782 and 1330 genes identified as being substantially upregulated and downregulated, respectively, in the FSAL-treated group. The identified genes and metabolites were mostly involved in redox processes and glycerolipid and amino acid metabolism pathways. FSAL offer a promising choice for food prevention and safety. KEY POINTS: • FSAL negatively affects the glycerolipid metabolism of B. cinerea • FSAL minimum inhibitory concentration against B. cinerea was 1.500 mg/mL • FSAL could be utilized as a new prevention strategy for gray mold in fruits.

Dietary fiber ameliorates lead-induced gut microbiota disturbance and alleviates neuroinflammation.

Dietary fiber (DF) is a carbohydrate from the edible part of plants and has the functions of promoting gastrointestinal motility, regulating gut microbiota (GM) and improving health. Lead is a non-essential toxic heavy metal that can accumulate in the environment over time and enter the body through the respiratory tract, skin and gastrointestinal tract. Lead not only causes disturbances in GM but also leads to loss of homeostasis of immune functions, causes neuronal damage and results in neuroinflammation. The scientific literature has reported that DF had anti-inflammatory activity as a natural product. This review highlights the role of DF and its metabolic products in alleviating lead-induced neuroinflammation by inducing changes in the species and quantity of GM and regulating the immune system, providing a potential dietary protective strategy for lead-induced disease. © 2022 Society of Chemical Industry.

Flavonoids and intestinal microbes interact to alleviate depression.

Flavonoids have a variety of biological activities that are beneficial to human health. However, owing to low bioavailability, most flavonoids exert beneficial effects in the intestine through metabolism by the flora into a variety of structurally different derivatives. Also, flavonoids can modulate the type and structure of intestinal microorganisms to improve human health. It has been reported that the development of depression is accompanied by changes in the type and number of intestinal microorganisms, and gut microbes can significantly improve depressive symptoms through the gut-brain axis. Therefore, the interaction between flavonoids and intestinal microbes to alleviate depression is discussed. © 2021 Society of Chemical Industry.