SUMMARY
The color of purple carrot taproots mainly depends on the anthocyanins sequestered in the vacuoles. Glutathione S‐transferases (GSTs) are key enzymes involved in anthocyanin transport. ...However, the precise mechanism of anthocyanin transport from the cytosolic surface of the endoplasmic reticulum (ER) to the vacuoles in carrots remains unclear. In this study, we conducted a comprehensive analysis of the carrot genome, leading to the identification of a total of 41 DcGST genes. Among these, DcGST1 emerged as a prominent candidate, displaying a strong positive correlation with anthocyanin pigmentation in carrot taproots. It was highly expressed in the purple taproot tissues of purple carrot cultivars, while it was virtually inactive in the non‐purple taproot tissues of purple and non‐purple carrot cultivars. DcGST1, a homolog of Arabidopsis thaliana TRANSPARENT TESTA 19 (TT19), belongs to the GSTF clade and plays a crucial role in anthocyanin transport. Using the CRISPR/Cas9 system, we successfully knocked out DcGST1 in the solid purple carrot cultivar ‘Deep Purple’ (‘DPP’), resulting in carrots with orange taproots. Additionally, DcMYB7, an anthocyanin activator, binds to the DcGST1 promoter, activating its expression. Compared with the expression DcMYB7 alone, co‐expression of DcGST1 and DcMYB7 significantly increased anthocyanin accumulation in carrot calli. However, overexpression of DcGST1 in the two purple carrot cultivars did not change the anthocyanin accumulation pattern or significantly increase the anthocyanin content. These findings improve our understanding of anthocyanin transport mechanisms in plants, providing a molecular foundation for improving and enhancing carrot germplasm.
Significance Statement
These findings improve our understanding of anthocyanin transport mechanisms in plants, providing a molecular foundation for improving and enhancing carrot germplasm.
The first domesticated carrots were thought to be purple carrots rich in anthocyanins. The anthocyanins biosynthesis in solid purple carrot taproot was regulated by DcMYB7 within P3 region containing ...a gene cluster of six DcMYBs. Here, we described a MYB gene within the same region, DcMYB11c, which was highly expressed in the purple pigmented petioles. Overexpression of DcMYB11c in ‘Kurodagosun’ (KRDG, orange taproot carrot with green petioles) and ‘Qitouhuang’ (QTHG, yellow taproot carrot with green petioles) resulted in deep purple phenotype in the whole carrot plants indicating anthocyanins accumulation. Knockout of DcMYB11c in ‘Deep Purple’ (DPPP, purple taproot carrot with purple petioles) through CRISPR/Cas9‐based genome editing resulted in pale purple phenotype due to the dramatic decrease of anthocyanins content. DcMYB11c could induce the expression of DcbHLH3 and anthocyanins biosynthesis genes to jointly promote anthocyanins biosynthesis. Yeast one‐hybrid assay (Y1H) and dual‐luciferase reporter assay (LUC) revealed that DcMYB11c bound to the promoters of DcUCGXT1 and DcSAT1 and directly activated the expression of DcUCGXT1 and DcSAT1 responsible for anthocyanins glycosylation and acylation, respectively. Three transposons were present in the carrot cultivars with purple petioles but not in the carrot cultivars with green petioles. We revealed the core factor, DcMYB11c, involved in anthocyanins pigmentation in carrot purple petioles. This study provides new insights into precise regulation mechanism underlying anthocyanins biosynthesis in carrot. The orchestrated regulation mechanism in carrot might be conserved across the plant kingdom and useful for other researchers working on anthocyanins accumulation in different tissues.
Summary statement
Here, we described a MYB gene, DcMYB11c, which was highly expressed in the purple pigmented petioles. The orchestrated regulation mechanism in carrot might be conserved across the plant kingdom and useful for other researchers working on anthocyanins accumulation in different tissues.
Evidence on preventing Alzheimer's disease (AD) is challenging to interpret due to varying study designs with heterogeneous endpoints and credibility. We completed a systematic review and ...meta-analysis of current evidence with prospective designs to propose evidence-based suggestions on AD prevention.
Electronic databases and relevant websites were searched from inception to 1 March 2019. Both observational prospective studies (OPSs) and randomised controlled trials (RCTs) were included. The multivariable-adjusted effect estimates were pooled by random-effects models, with credibility assessment according to its risk of bias, inconsistency and imprecision. Levels of evidence and classes of suggestions were summarised.
A total of 44 676 reports were identified, and 243 OPSs and 153 RCTs were eligible for analysis after exclusion based on pre-decided criteria, from which 104 modifiable factors and 11 interventions were included in the meta-analyses. Twenty-one suggestions are proposed based on the consolidated evidence, with Class I suggestions targeting 19 factors: 10 with Level A strong evidence (education, cognitive activity, high body mass index in latelife, hyperhomocysteinaemia, depression, stress, diabetes, head trauma, hypertension in midlife and orthostatic hypotension) and 9 with Level B weaker evidence (obesity in midlife, weight loss in late life, physical exercise, smoking, sleep, cerebrovascular disease, frailty, atrial fibrillation and vitamin C). In contrast, two interventions are not recommended: oestrogen replacement therapy (Level A2) and acetylcholinesterase inhibitors (Level B).
Evidence-based suggestions are proposed, offering clinicians and stakeholders current guidance for the prevention of AD.
The aetiology of Alzheimer's disease (AD) is believed to involve environmental exposure and genetic susceptibility. The aim of our present systematic review and meta-analysis was to roundly evaluate ...the association between AD and its modifiable risk factors.
We systematically searched PubMed and the Cochrane Database of Systematic Reviews from inception to July 2014, and the references of retrieved relevant articles. We included prospective cohort studies and retrospective case-control studies.
16,906 articles were identified of which 323 with 93 factors met the inclusion criteria for meta-analysis. Among factors with relatively strong evidence (pooled population >5000) in our meta-analysis, we found grade I evidence for 4 medical exposures (oestrogen, statin, antihypertensive medications and non-steroidal anti-inflammatory drugs therapy) as well as 4 dietary exposures (folate, vitamin E/C and coffee) as protective factors of AD. We found grade I evidence showing that one biochemical exposure (hyperhomocysteine) and one psychological condition (depression) significantly increase risk of developing AD. We also found grade I evidence indicative of complex roles of pre-existing disease (frailty, carotid atherosclerosis, hypertension, low diastolic blood pressure, type 2 diabetes mellitus (Asian population) increasing risk whereas history of arthritis, heart disease, metabolic syndrome and cancer decreasing risk) and lifestyle (low education, high body mass index (BMI) in mid-life and low BMI increasing the risk whereas cognitive activity, current smoking (Western population), light-to-moderate drinking, stress, high BMI in late-life decreasing the risk) in influencing AD risk. We identified no evidence suggestive of significant association with occupational exposures.
Effective interventions in diet, medications, biochemical exposures, psychological condition, pre-existing disease and lifestyle may decrease new incidence of AD.
Electrochemical reduction of CO2 is a compelling route to store renewable electricity in the form of carbon‐based fuels. Efficient electrochemical reduction of CO2 requires catalysts that combine ...high activity, high selectivity, and low overpotential. Extensive surface reconstruction of metal catalysts under high productivity operating conditions (high current densities, reducing potentials, and variable pH) renders the realization of tailored catalysts that maximize the exposure of the most favorable facets, the number of active sites, and the oxidation state all the more challenging. Earth‐abundant transition metals such as tin, bismuth, and lead have been proven stable and product‐specific, but exhibit limited partial current densities. Here, a strategy that employs bismuth oxyhalides as a template from which 2D bismuth‐based catalysts are derived is reported. The BiOBr‐templated catalyst exhibits a preferential exposure of highly active Bi (11¯0) facets. Thereby, the CO2 reduction reaction selectivity is increased to over 90% Faradaic efficiency and simultaneously stable current densities of up to 200 mA cm−2 are achieved—more than a twofold increase in the production of the energy‐storage liquid formic acid compared to previous best Bi catalysts.
A 2D bismuth oxyhalide‐templated catalyst for CO2 electroreduction exhibits an in operando preferential facet exposure, which enables sustaining near‐unity selectivity to formate production even at high current densities up to 200 mA cm−2.
Abstract Background Neuropsychiatric symptoms (NPS) are being increasingly recognized as common serious problems in Alzheimer’s disease (AD). However, published data on the prevalence of NPS in ...persons with AD are conflicting. This meta-analysis aimed to estimate the prevalence of NPS in persons with AD. Methods Studies published from 1964 to September 30, 2014, were identified from PubMed and Embase database, reference lists and conference abstracts. We calculated prevalence rates and conducted meta-regression analysis with random-effects model, according to study characteristics, population demographics or condition information. Results We identified 48 eligible articles, which provided data for 12 NPS reported in Neuropsychiatric Inventory (NPI). The most frequent NPS was apathy, with an overall prevalence of 49% (95% CI 41–57%), followed by depression, aggression, anxiety and sleep disorder, the pooled prevalence estimates of which were 42% (95% CI 37–46%), 40% (95% CI 33–46%), 39% (95% CI 32–46%) and 39% (95% CI 30–47%), respectively. The less prevalent NPS were irritability (36%, 31–41%), appetite disorder (34%, 27–41%), aberrant motor behavior (32%, 25–38%), delusion (31%, 27–35%), disinhibition (17%, 12–21%) and hallucination (16%, 13–18%). Least common was euphoria, with an overall prevalence of 7% (95% CI 5–9%). Limitations Several aspects, such as the quality of included studies were not always optimal and there was significant heterogeneity of prevalence estimate across studies. Conclusions NPS were observed to be highly prevalent in AD patients. Disease duration, age, education level, population origin and the severity of cognitive impairment had influence on the prevalence of some NPS.
Organic–inorganic hybrid perovskite solar cells (PSCs) have seen a rapid rise in power conversion efficiencies in recent years; however, they still suffer from interfacial recombination and charge ...extraction losses at interfaces between the perovskite absorber and the charge–transport layers. Here, in situ back‐contact passivation (BCP) that reduces interfacial and extraction losses between the perovskite absorber and the hole transport layer (HTL) is reported. A thin layer of nondoped semiconducting polymer at the perovskite/HTL interface is introduced and it is shown that the use of the semiconductor polymer permits—in contrast with previously studied insulator‐based passivants—the use of a relatively thick passivating layer. It is shown that a flat‐band alignment between the perovskite and polymer passivation layers achieves a high photovoltage and fill factor: the resultant BCP enables a photovoltage of 1.15 V and a fill factor of 83% in 1.53 eV bandgap PSCs, leading to an efficiency of 21.6% in planar solar cells.
An in situ back‐contact passivation strategy is adopted to optimize the photovoltaic performance of n–i–p planar perovskite solar cells. Devices with a flat‐band alignment between the perovskite and polymer passivation layer achieve a high photovoltage of 1.15 V and fill factor of 83% with 1.53 eV bandgap perovskite, leading to a stabilized power conversion efficiency of 21.6%.
We sought to identify the risk factors for predicting the progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD).
We searched 6 electronic databases for cohort studies published ...from January 1966 to March 2015. Eligible studies were required to be relevant to the subject and provide sufficient data for our needs.
60 cohort studies with 14,821 participants from 16 countries were included in the meta-analysis. The strongest positive associations between risk factors and the progression from MCI to AD were found for abnormal cerebrospinal fluid (CSF), phosphorylated τ (p-τ) (relative risk (RR)=2.43, 95% CI=1.70 to 3.48), abnormal CSF τ/Aβ1-42 (RR=3.77, 95% CI=2.34 to 6.09), hippocampal atrophy (RR=2.59, 95% CI=1.95 to 3.44), medial temporal lobe atrophy (RR=2.11, 95% CI=1.70 to 2.63) and entorhinal atrophy (RR=2.03, 95% CI=1.57 to 2.62). Further positive associations were found for the presence of apolipoprotein E (APOE)ε4ε4 and at least 1 APOEε4 allele, CSF total-τ (t-τ), white matter hyperintensity volume, depression, diabetes, hypertension, older age, female gender, lower mini-mental state examination (MMSE) score and higher AD assessment scale cognitive subscale (ADAS-cog) score. Negative associations were found for high body mass index (RR=0.85, 95% CI=0.76 to 0.96) and higher auditory verbal learning test delay score (RR=0.86, 95% CI=0.77 to 0.96).
Patients with MCI with APOEε4, abnormal CSF τ level, hippocampal and medial temporal lobe atrophy, entorhinal atrophy, depression, diabetes, hypertension, older age, female gender, lower MMSE score and higher ADAS-cog score, had a high risk for the progression to AD.
Electrochemical conversion of nitrate (NO3 –) into ammonia (NH3) recycles nitrogen and offers a route to the production of NH3, which is more valuable than dinitrogen gas. However, today’s ...development of NO3 – electroreduction remains hindered by the lack of a mechanistic picture of how catalyst structure may be tuned to enhance catalytic activity. Here we demonstrate enhanced NO3 – reduction reaction (NO3 –RR) performance on Cu50Ni50 alloy catalysts, including a 0.12 V upshift in the half-wave potential and a 6-fold increase in activity compared to those obtained with pure Cu at 0 V vs reversible hydrogen electrode (RHE). Ni alloying enables tuning of the Cu d-band center and modulates the adsorption energies of intermediates such as *NO3 –, *NO2, and *NH2. Using density functional theory calculations, we identify a NO3 –RR-to-NH3 pathway and offer an adsorption energy–activity relationship for the CuNi alloy system. This correlation between catalyst electronic structure and NO3 –RR activity offers a design platform for further development of NO3 –RR catalysts.
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