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Background: Available data concerning the contribution of patient adverse drug reaction (ADR) reporting in practice are scarce. Few studies have compared patients' reports with reports from healthcare professionals (HCPs). During the 2009-10 mass immunization campaign with A (H1N1)v2009 pandemic influenza vaccines, a reinforced pharmacovigilance plan was introduced in France according to European Medicines Agency recommendations. For the first time, patients were offered the opportunity to report suspected ADRs to pandemic vaccines directly to regional pharmacovigilance centres.Objective: The aim of the study was to compare the characteristics of patient and HCP ADR reports in order to assess the qualitative and quantitative contribution of patient reporting to the French Pharmacovigilance System.Methods: All spontaneous ADRs registered into the French Pharmacovigilance Database from 21 October 2009 to 15 June 2010, in which either one of the most frequently administered pandemic vaccines (i.e. Panenza® or Pandemrix®) was involved, were analysed. ADRs were classified as 'serious', 'medically serious' and 'non-serious'. This study focused on 'serious' and 'medically serious' ADRs. An ADR was ranked as 'medically serious' when it required medical intervention or hospitalization within less than 24 hours. In each level of seriousness, frequency of 'unlabelled' ADRs, ADRs of 'special interest', imputability scores and category of ADRs according to Medical Dictionary for Regulatory Activitives (MedDRA®) primary System Organ Class were compared between patient and professional reports.Results: Among the 4746 reports received during the study period, 1006 (21.2%) originated from patients. HCPs reported significantly more 'medically serious' or 'serious' ADRs than patients (15.1% [565/3740] vs 8.4% [85/1006], respectively; p < 0.001). No difference was found in 'unlabelled, serious' ADRs between patients and HCPs (56.5% [n = 13] vs 56.7% [n = 136], respectively).Conclusions: In this first French experience of formal patient participation to ADR reporting, patient contribution to the total number of ADRs reached 21.2%. This study revealed no major qualitative difference between patient and HCP reports. ADR profiles reported by patients appeared to be consistent with those from professionals. Further investigations are necessary to assess the intrinsic quality of notification forms coming from non-professional reporters. However, this study is of particular interest in the context of publication of the first governmental decree that will formally integrate patient participation to the current French ADR reporting scheme. [ABSTRACT FROM AUTHOR]

Expert curation is essential to capture knowledge of enzyme functions from the scientific literature in FAIR open knowledgebases but cannot keep pace with the rate of new discoveries and new publications. In this work we present EnzChemRED, for Enzyme Chemistry Relation Extraction Dataset, a new training and benchmarking dataset to support the development of Natural Language Processing (NLP) methods such as (large) language models that can assist enzyme curation. EnzChemRED consists of 1,210 expert curated PubMed abstracts where enzymes and the chemical reactions they catalyze are annotated using identifiers from the protein knowledgebase UniProtKB and the chemical ontology ChEBI. We show that fine-tuning language models with EnzChemRED significantly boosts their ability to identify proteins and chemicals in text (86.30% F 1 score) and to extract the chemical conversions (86.66% F 1 score) and the enzymes that catalyze those conversions (83.79% F 1 score). We apply our methods to abstracts at PubMed scale to create a draft map of enzyme functions in literature to guide curation efforts in UniProtKB and the reaction knowledgebase Rhea., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

The Gene Ontology (GO) knowledgebase (http://geneontology.org) is a comprehensive resource concerning the functions of genes and gene products (proteins and noncoding RNAs). GO annotations cover genes from organisms across the tree of life as well as viruses, though most gene function knowledge currently derives from experiments carried out in a relatively small number of model organisms. Here, we provide an updated overview of the GO knowledgebase, as well as the efforts of the broad, international consortium of scientists that develops, maintains, and updates the GO knowledgebase. The GO knowledgebase consists of three components: (1) the GO-a computational knowledge structure describing the functional characteristics of genes; (2) GO annotations-evidence-supported statements asserting that a specific gene product has a particular functional characteristic; and (3) GO Causal Activity Models (GO-CAMs)-mechanistic models of molecular "pathways" (GO biological processes) created by linking multiple GO annotations using defined relations. Each of these components is continually expanded, revised, and updated in response to newly published discoveries and receives extensive QA checks, reviews, and user feedback. For each of these components, we provide a description of the current contents, recent developments to keep the knowledgebase up to date with new discoveries, and guidance on how users can best make use of the data that we provide. We conclude with future directions for the project., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of The Genetics Society of America.)

Maintaining a metabolic steady state is essential for an organism's fitness and survival when confronted with environmental stress, and metabolic imbalance can be reversed by exposing the organism to fasting. Here, we attempted to apply this physiological principle to mammalian cell cultures to improve cellular fitness and consequently their ability to express recombinant proteins. We showed that transient vitamin B5 deprivation, an essential cofactor of central cellular metabolism, can quickly and irreversibly affect mammalian cell growth and division. A selection method was designed that relies on mammalian cell dependence on vitamin B5 for energy production, using the co-expression of the B5 transporter SLC5A6 and a gene of interest. We demonstrated that vitamin B5 selection persistently activates peroxisome proliferator-activated receptors (PPAR), a family of transcription factors involved in energy homeostasis, thereby altering lipid metabolism, improving cell fitness and therapeutic protein production. Thus, stable PPAR activation may constitute a cellular memory of past deprivation state, providing increased resistance to further potential fasting events. In other words, our results imply that cultured cells, once exposed to metabolic starvation, may display an improved metabolic fitness as compared to non-exposed cells, allowing increased resistance to cellular stress., Competing Interests: Declaration of competing interest Some of the authors are employed by Selexis SA, a company that generates CHO cell clones expressing therapeutic proteins., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

In plants, metabolic homeostasis-the driving force of growth and development-is achieved through the dynamic behavior of a network of enzymes, many of which depend on coenzymes for activity. The circadian clock is established to influence coordination of supply and demand of metabolites. Metabolic oscillations independent of the circadian clock, particularly at the subcellular level is unexplored. Here, we reveal a metabolic rhythm of the essential coenzyme thiamine diphosphate (TDP) in the Arabidopsis nucleus. We show there is temporal separation of the clock control of cellular biosynthesis and transport of TDP at the transcriptional level. Taking advantage of the sole reported riboswitch metabolite sensor in plants, we show that TDP oscillates in the nucleus. This oscillation is a function of a light-dark cycle and is independent of circadian clock control. The findings are important to understand plant fitness in terms of metabolite rhythms.

In this study, we assessed the importance of cytoskeleton organization in the mammalian cells used to produce therapeutic proteins. Two cytoskeletal genes, Actin alpha cardiac muscle 1 (ACTC1) and a guanosine triphosphate GTPase-activating protein (TAGAP), were found to be upregulated in highly productive therapeutic protein-expressing Chinese hamster ovary (CHO) cells selected by the deprivation of vitamin B5. We report here that the overexpression of the ACTC1 protein was able to improve significantly recombinant therapeutic production, as well as to decrease the levels of toxic lactate metabolic by-products. ACTC1 overexpression was accompanied by altered as well as decreased polymerized actin, which was associated with high protein production by CHO cell cultured in suspension. We suggest that the depolymerization of actin and the possible modulation of integrin signaling, as well as changes in basal metabolism, may be driving the increase of protein secretion by CHO cells., (© 2020 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals, Inc.)

Objective: It is often asserted that the crowding phenomenon in emergency departments (ED) can be explained by an increase in visits considered as non-urgent. The aim of our study was to quantify the increase in ED visit rates and to determine whether this increase was explained by non-severe visit types., Methods: This observational study covers all ED visits between 2002 and 2015 by adult inhabitants of the Midi-Pyrénées region in France. Their characteristics were collected from the emergency visit summaries. We modelled the visit rates per year using linear regression models, and an increase was considered significant when the 95% CIs did not include zero. The severity of the patients' condition during ED visit was determined through the 'Clinical Classification of Emergency' score. Non-severe visits were those where the patient was stable, and the physician deemed no intervention necessary. Intermediate-severity visits concerned patients who were stable but requiring diagnostic or therapeutic procedures., Results: The 37 studied EDs managed >7 million visits between 2002 and 2015. There was an average increase of +4.83 (95% CI 4.33 to 5.32) visits per 1000 inhabitants each year. The increase in non-severe visit types was +0.88 (95% CI 0.42 to 1.34) per 1000 inhabitants, while the increase in intermediate-severity visit types was +3.26 (95% CI 2.62 to 3.91) per 1000 inhabitants. This increase affected all age groups and all sexes., Discussion: It appears that the increase in ED use is not based on an increase in non-severe visit types, with a greater impact of intermediate-severity visit types requiring diagnostic or therapeutic procedures in ED., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: To analyse the association between patients' socioeconomic position (SEP) and the use of emergency departments (EDs)., Methods: This population-based study included all visits to ED in 2012 by inhabitants of the French Midi-Pyrénées region, recorded by the Regional Emergency Departments Observatory. We compared ED visit rates and the proportion of non-severe visits according to the patients' SEP as assessed by the European Deprivation Index., Results: We analysed 496,388 visits. The annual ED visit rate increased with deprivation level: 165.9 [95% CI (164.8-166.9)] visits per 1000 inhabitants among the most advantaged group, compared to 321.9 [95% CI (320.3-323.5)] per 1000 among the most disadvantaged. However, the proportion of non-severe visits was about 14% of the visits, and this proportion did not differ according to SEP., Conclusions: Although the study shows a difference of ED visit rates, the probability of a visit being non-severe is not meaningfully different according to SEP. This supports the assumption that ED visit rate variations according to SEP are mainly explained by SEP-related differences in health states rather than SEP-related differences in health behaviours.

Patients with borderline personality disorder (BPD) have been shown to have increased rates of the use of medical services. The objective of this multicentre study was to compare the utilization of physical health services by patients with severe BPD (n = 36) with that of two control groups: one with other personality disorders (PDs) (n = 38) and one with matched subjects randomly selected from the general population (n = 165). Information was drawn from an insurance database collected over a 5-year period. The results showed that the BPD group had a higher mean number of medication prescriptions (377.3 vs. 97.4, p < 0.001), general medical consultations (34.4 vs. 13.2, p < 0.05) and days of medical or surgical hospitalization (10.2 vs. 1.9, p = 0.03). However, there were no significant differences between the groups with BPD and other PDs. The annual health-care cost for each BPD patient is estimated to be 12 761 euros, of which 17.6% is due to somatic care. In the BPD group, co-morbidity for narcissistic PD (NPD) contributed to the overall use of medications and hospitalization use. Combined with other data, this exploratory study shows that BPD is a medical burden and not just a psychiatric one. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

Background: Parkinson's disease (PD) is characterized by its impact on quality of life, constituting a substantial economic burden on society. Education programs implicating patients more in the management of their illness and complementing medical treatment may be a beneficial adjunct in PD. This study assessed the impact of an education program on quality of life and its cost-effectiveness in PD patients., Methods: This single-center, prospective, randomized study assessed an education program consisting of individual and group sessions over a 12-month period. A total of 120 PD patients were assigned to either the Treated by Behavioral Intervention group (TTBI) or the no TTBI group. The primary outcome criterion was quality of life assessed using PDQ39. The Unified Parkinson's Disease Rating Scale (UPDRS) and psychological status were collected. An economic evaluation was performed, including calculations of incremental cost-effectiveness ratios (ICERs)., Results: After 12 months of follow-up, changes recorded in the PDQ39 between the groups were not significantly different but better changes were observed in each dimension in the TTBI group compared to the no TTBI group. UPDRS I, II and total score were significantly improved in TTBI group compared to the no TTBI group. Mean annual costs did not differ significantly between the two groups., Conclusion: This study suggested that the education program positively impacts the perceived health of PD patients without increasing medical costs., Competing Interests: The authors have declared that no competing interests exist.

Background: Given the growing worldwide market of non-prescription drugs, monitoring their misuse in the context of self-medication represents a particular challenge in Public Health. The aim of this study was to investigate the prevalence of misuse, abuse, and dependence on non-prescription psychoactive drugs., Method: During one month, in randomly solicited community pharmacies, an anonymous questionnaire was offered to adults requesting paracetamol (control group), codeine combined with paracetamol in analgesics, or sedative H1 antihistamines. Responses about misuse (drug use not in agreement with the Patient Information Leaflet) abuse (excessive drug use having detrimental consequences), and dependence (established according to questions adapted from the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition criteria) on psychoactive drugs were compared to those of the paracetamol control group., Results: 295 patients (mean age 48.5 years, 68.5% of women) having used one of the studied drugs during the previous month were included. Misuse and dependence to codeine analgesics concerned 6.8% and 17.8% of the patients exposed to these drugs, respectively, (n = 118), which was significantly higher than for paracetamol. 19.5% had used codeine analgesics daily for more than six months. Headache was the most frequent reason for persistent daily use. A high prevalence of persistent daily users of sedative H1 antihistamines was also observed. Whereas these drugs are recommended only for short treatment courses of occasional insomnia, 72.2% of the participants having taken doxylamine (n = 36) were daily users, predominantly for more than six months., Conclusions: Results on misuse and dependence on non-prescription codeine analgesics suggest that chronic pain, in particular chronic cephalalgia, requires better medical care. In addition, as for hypnotics on prescription, persistent use of doxylamine for self-medication is not justified until an acceptable benefit-risk ratio for chronic sleep disturbance is shown by clinical data.

Vitamin B6 is a cofactor for more than 140 essential enzymatic reactions and was recently proposed as a potent antioxidant, playing a role in the photoprotection of plants. De novo biosynthesis of the vitamin has been described relatively recently and is derived from simple sugar precursors as well as glutamine. In addition, the vitamin can be taken up from exogenous sources in a broad range of organisms, including plants. However, specific transporters have been identified only in yeast. Here we assess the ability of the family of Arabidopsis purine permeases (PUPs) to transport vitamin B6. Several members of the family complement the growth phenotype of a Saccharomyces cerevisiae mutant strain impaired in both de novo biosynthesis of vitamin B6 as well as its uptake. The strongest activity was observed with PUP1 and was confirmed by direct measurement of uptake in yeast as well as in planta, defining PUP1 as a high affinity transporter for pyridoxine. At the tissue level the protein is localised to hydathodes and here we use confocal microscopy to illustrate that at the cellular level it is targeted to the plasma membrane. Interestingly, we observe alterations in pyridoxine recycling from the guttation sap upon overexpression of PUP1 and in a pup1 mutant, consistent with the role of the protein in retrieval of pyridoxine. Furthermore, combining the pup1 mutant with a vitamin B6 de novo biosynthesis mutant (pdx1.3) corroborates that PUP1 is involved in the uptake of the vitamin., (© 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.)

Thiamin (vitamin B1) is made by plants and microorganisms but is an essential micronutrient in the human diet. All organisms require it as a cofactor in its form as thiamin pyrophosphate (TPP) for the activity of key enzymes of central metabolism. In humans, deficiency is widespread particularly in populations where polished rice is a major component of the diet. Considerable progress has been made on the elucidation of the biosynthesis pathway within the last few years enabling concrete strategies for biofortification purposes to be devised, with a particular focus here on genetic engineering. Furthermore, the vitamin has been shown to play a role in both abiotic and biotic stress responses. The precursors for de novo biosynthesis of thiamin differ between microorganisms and plants. Bacteria use intermediates derived from purine and isoprenoid biosynthesis, whereas the pathway in yeast involves the use of compounds from the vitamin B3 and B6 groups. Plants on the other hand use a combination of the bacterial and yeast pathways and there is subcellular partitioning of the biosynthesis steps. Specifically, thiamin biosynthesis occurs in the chloroplast of plants through the separate formation of the pyrimidine and thiazole moieties, which are then coupled to form thiamin monophosphate (TMP). Phosphorylation of thiamin to form TPP occurs in the cytosol. Therefore, thiamin (or TMP) must be exported from the chloroplast to the cytosol for the latter step to be executed. The regulation of biosynthesis is mediated through riboswitches, where binding of the product TPP to the pre-mRNA of a biosynthetic gene modulates expression. Here we examine and hypothesize on genetic engineering approaches attempting to increase the thiamin content employing knowledge gained with the model plant Arabidopsis thaliana. We will discuss the regulatory steps that need to be taken into consideration and can be used a prerequisite for devising such strategies in crop plants.

In addition to the classical functions of flavonoids in the response to biotic/abiotic stress conditions, these phenolic compounds have been implicated in the modulation of various developmental processes. These findings suggest that flavonoids are more integral components of the plant signaling machinery than traditionally recognized. To understand how flux through the flavonoid pathway affects plant cellular processes, we used wild-type and chalcone isomerase mutant (transparent testa 5, tt5) seedlings grown under anthocyanin inductive conditions, in the presence or absence of the flavonoid intermediate naringenin, the product of the chalcone isomerase enzyme. Because flavonoid biosynthetic genes are expressed under anthocyanin inductive conditions regardless of whether anthocyanins are formed or not, this system provides an excellent opportunity to specifically investigate the molecular changes associated with increased flux through the flavonoid pathway. By assessing genome-wide mRNA accumulation changes in naringenin-treated and untreated tt5 and wild-type seedlings, we identified a flavonoid-responsive gene set associated with cellular trafficking, stress responses and cellular signaling. Jasmonate biosynthetic genes were highly represented among the signaling pathways induced by increased flux through the flavonoid pathway. In contrast to studies showing a role for flavonoids in the control of auxin transport, no effect on auxin-responsive genes was observed. Taken together, our data suggest that Arabidopsis can sense flavonoids as a signal for multiple fundamental cellular processes., (© 2013 The Authors The Plant Journal © 2013 Blackwell Publishing Ltd.)

Pericarp Color1 (P1) encodes an R2R3-MYB transcription factor responsible for the accumulation of insecticidal flavones in maize (Zea mays) silks and red phlobaphene pigments in pericarps and other floral tissues, which makes P1 an important visual marker. Using genome-wide expression analyses (RNA sequencing) in pericarps and silks of plants with contrasting P1 alleles combined with chromatin immunoprecipitation coupled with high-throughput sequencing, we show here that the regulatory functions of P1 are much broader than the activation of genes corresponding to enzymes in a branch of flavonoid biosynthesis. P1 modulates the expression of several thousand genes, and ∼1500 of them were identified as putative direct targets of P1. Among them, we identified F2H1, corresponding to a P450 enzyme that converts naringenin into 2-hydroxynaringenin, a key branch point in the P1-controlled pathway and the first step in the formation of insecticidal C-glycosyl flavones. Unexpectedly, the binding of P1 to gene regulatory regions can result in both gene activation and repression. Our results indicate that P1 is the major regulator for a set of genes involved in flavonoid biosynthesis and a minor modulator of the expression of a much larger gene set that includes genes involved in primary metabolism and production of other specialized compounds.

PURPOSE: Addictive behaviours are often associated with hidden characteristics that are difficult to detect by usual approaches. This study aimed to estimate the incidence of serious drug-related complications by using the capture-recapture method in defined geographical area. METHODS: Hospitalizations with mention of disorders related to drug of abuse were considered serious drug-related complications. We searched these cases in and crossed three sources of data: spontaneous reports of drug of abuse-related disorders called NotS ('Notification Spontanee') collected by the regional addictovigilance centre, computerised hospital database Programme de Medicalisation des Systemes d'Information (PMSI) and toxicological analyses (TA) carried out for hospitalized patients. RESULTS: In 2007 and 2008, 1509 distinct cases were captured. After data modelling, the estimated number of psychoactive drug-related hospitalizations was 4744 (95%CI = 4060-5429). Most frequent products were opioids (34%), cannabis (19%) and cocaine (13%). 'Multiple drugs' were observed in 26% of cases. The incidence of serious drug-related complications in the area covered should be estimated at 5.7 (95%CI = 5.5-5.9) per thousand 15- to 64-year-old inhabitants. The exhaustiveness of sources were 0.4% (95%CI = 0.2-0.6) for NotS, 11.6% (95%CI = 10.7-12.5) for TA and 22.6% (95%CI = 21.4-23.8) for PMSI. CONCLUSIONS: The 'real' number of cases far exceeds that of cases that can be identified through simple counts. In particular, it confirms the underreporting and even quantifies its magnitude. These results confirm that drug users are frequently hospitalised and require heavy medical management. Moreover, these results show the real although limited advantage of hospitalization database in detecting drug associated disorders in epidemiological studies. Copyright © 2012 John Wiley & Sons, Ltd., (Copyright © 2012 John Wiley & Sons, Ltd.)

Fourteen benzodiazepine (BZD) or BZD-like medications were analyzed with three data sources aiming to assess prescription drug abuse for the year 2008. After a descriptive analysis, a principal component analysis was carried out to explore correlations between seven indicators obtained by different methods using these three different data sources and to compute a composite score of diversion for these drugs. For all the indicators, flunitrazepam appears first with much higher values than the other drugs, whereas clonazepam appears in the second or third place. These methods produce globally correlated indicators and the composite score obtained from principal component analysis ranks the drugs with the highest diversion as follows: flunitrazepam, clonazepam, oxazepam, diazepam, and bromazepam. This study shows that these methods yield consistent results. Their integration into a single multi-indicator approach gives health authorities a global view of different behaviors regarding diversion of a given drug.

Sortin1 is a chemical genetic-hit molecule that causes specific mislocalization of plant and yeast-soluble and membrane vacuolar markers. To better understand its mode of action, we designed a Sortin1-hypersensitive screen and identified several Sortin1-hypersensitive and flavonoid-defective mutants. Mechanistically, Sortin1 mimics the effect of the glutathione inhibitor buthionine sulfoximine and alters the vacuolar accumulation of flavonoids, likely blocking their transport through vacuole-localized ABC transporters. Structure-activity relationship studies conducted in Arabidopsis revealed the structural requirements for Sortin1 bioactivity and demonstrated that overlapping Sortin1 substructures can be used to discriminate between vacuolar-flavonoid accumulations and vacuolar-biogenesis defects. We conclude that Sortin1 is a valuable probe for dissecting novel links among flavonoid transport, vacuolar integrity, and the trafficking of vacuolar targeted cargoes in Arabidopsis., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Patients with Parkinson's disease (PD) frequently experience pain that could be in part due to central modification of nociception. In this randomized controlled double blind study, we compared the effect of apomorphine versus placebo on pain thresholds and pain-induced cerebral activity in 25 patients with PD. Subjective pain threshold (using thermal stimulation, thermotest), objective pain threshold (nociceptive flexion reflex), and cerebral activity (H(2)(15)O PET) during noxious and innocuous stimulations were performed. Neither subjective nor objective pain thresholds nor pain activation profile were modified by apomorphine compared with placebo in 25 PD patients. Apomorphine has no effect on pain processing in PD. We suggest that other monoamine systems than dopaminergic system could be involved., (Copyright © 2010 Movement Disorder Society.)

Flavonols are important compounds for conditional male fertility in maize (Zea mays) and other crops, and they also contribute to protecting plants from UV-B radiation. However, little continues to be known on how maize and other grasses synthesize flavonols, and how flavonol biosynthesis is regulated. By homology with an Arabidopsis flavonol synthase (AtFLS1), we cloned a maize gene encoding a protein (ZmFLS1) capable of converting the dihydrokaempferol (DHK) and dihydroquercetin (DHQ) dihydroflavonols to the corresponding flavonols, kaempferol (K) and quercetin (Q). Moreover, ZmFLS1 partially complements the flavonol deficiency of the Arabidopsis fls1 mutant, and restores anthocyanin accumulation to normal levels. We demonstrate that ZmFLS1 is under the control of the anthocyanin (C1/PL1 + R/B) and 3-deoxy flavonoid (P1) transcriptional regulators. Indeed, using chromatin immunoprecipitation (ChIP) experiments, we establish that ZmFLS1 is an immediate direct target of the P1 and C1/R regulatory complexes, revealing similar control as for earlier steps in the maize flavonoid pathway. Highlighting the importance of flavonols in UV-B protection, we also show that ZmFLS1 is induced in maize seedlings by UV-B, and that this induction is in part mediated by the increased expression of the P1, B and PL1 regulators. Together, our results identify a key flavonoid biosynthetic enzyme so far missed in maize and other monocots, and illustrate mechanisms by which flavonol accumulation is controlled in maize.

Anthocyanins are flavonoid pigments that accumulate in the large central vacuole of most plants. Inside the vacuole, anthocyanins can be found uniformly distributed or as part of sub-vacuolar pigment bodies, the Anthocyanic Vacuolar Inclusions (AVIs). Using Arabidopsis seedlings grown under anthocyanin-inductive conditions as a model to understand how AVIs are formed, we show here that the accumulation of AVIs strongly correlates with the formation of cyanidin 3-glucoside (C3G) and derivatives. Arabidopsis mutants that fail to glycosylate anthocyanidins at the 5-O position (5gt mutant) accumulate AVIs in almost every epidermal cell of the cotyledons, as compared to wild-type seedlings, where only a small fraction of the cells show AVIs. A similar phenomenon is observed when seedlings are treated with vanadate. Highlighting a role for autophagy in the formation of the AVIs, we show that various mutants that interfere with the autophagic process (atg mutants) display lower numbers of AVIs, in addition to a reduced accumulation of anthocyanins. Interestingly, vanadate increases the numbers of AVIs in the atg mutants, suggesting that several pathways might participate in AVI formation. Taken together, our results suggest novel mechanisms for the formation of sub-vacuolar compartments capable of accumulating anthocyanin pigments.

Plants produce a very large number of specialized compounds that must be transported from their site of synthesis to the sites of storage or disposal. Anthocyanin accumulation has provided a powerful system to elucidate the molecular and cellular mechanisms associated with the intracellular trafficking of phytochemicals. Benefiting from the unique fluorescent properties of anthocyanins, we show here that in Arabidopsis (Arabidopsis thaliana), one route for anthocyanin transport to the vacuole involves vesicle-like structures shared with components of the secretory pathway. By colocalizing the red fluorescence of the anthocyanins with green fluorescent protein markers of the endomembrane system in Arabidopsis seedlings, we show that anthocyanins are also sequestered to the endoplasmic reticulum and to endoplasmic reticulum-derived vesicle-like structures targeted directly to the protein storage vacuole in a Golgi-independent manner. Moreover, our results indicate that vacuolar accumulation of anthocyanins does not depend solely on glutathione S-transferase activity or ATP-dependent transport mechanisms. Indeed, we observed a dramatic increase of anthocyanin-filled subvacuolar structures, without a significant effect on total anthocyanin levels, when we inhibited glutathione S-transferase activity, or the ATP-dependent transporters with vanadate, a general ATPase inhibitor. Taken together, these results provide evidence for an alternative novel mechanism of vesicular transport and vacuolar sequestration of anthocyanins in Arabidopsis.

Phenotypic characterization of the Arabidopsis thaliana transparent testa12 (tt12) mutant encoding a membrane protein of the multidrug and toxic efflux transporter family, suggested that TT12 is involved in the vacuolar accumulation of proanthocyanidin precursors in the seed. Metabolite analysis in tt12 seeds reveals an absence of flavan-3-ols and proanthocyanidins together with a reduction of the major flavonol quercetin-3-O-rhamnoside. The TT12 promoter is active in cells synthesizing proanthocyanidins. Using translational fusions between TT12 and green fluorescent protein, it is demonstrated that this transporter localizes to the tonoplast. Yeast vesicles expressing TT12 can transport the anthocyanin cyanidin-3-O-glucoside in the presence of MgATP but not the aglycones cyanidin and epicatechin. Inhibitor studies demonstrate that TT12 acts in vitro as a cyanidin-3-O-glucoside/H(+)-antiporter. TT12 does not transport glycosylated flavonols and procyanidin dimers, and a direct transport activity for catechin-3-O-glucoside, a glucosylated flavan-3-ol, was not detectable. However, catechin-3-O-glucoside inhibited TT12-mediated transport of cyanidin-3-O-glucoside in a dose-dependent manner, while flavan-3-ol aglycones and glycosylated flavonols had no effect on anthocyanin transport. It is proposed that TT12 transports glycosylated flavan-3-ols in vivo. Mutant banyuls (ban) seeds accumulate anthocyanins instead of proanthocyanidins, yet the ban tt12 double mutant exhibits reduced anthocyanin accumulation, which supports the transport data suggesting that TT12 mediates anthocyanin transport in vitro.

Functional characterization of genes involved in the flavonoid metabolism and its regulation requires in-depth analysis of flavonoid structure and composition of seed from the model plant Arabidopsis thaliana. Here, we report an analysis of the diverse and specific flavonoids that accumulate during seed development and maturation in wild types and mutants. Wild type seed contained more than 26 different flavonoids belonging to flavonols (mono and diglycosylated quercetin, kaempferol and isorhamnetin derivatives) and flavan-3-ols (epicatechin monomers and soluble procyanidin polymers with degrees of polymerization up to 9). Most of them are described for the first time in Arabidopsis. Interestingly, a novel group of four biflavonols that are dimers of quercetin-rhamnoside was also detected. Quercetin-3-O-rhamnoside (the major flavonoid), biflavonols, epicatechin and procyanidins accumulated in the seed coat in contrast to diglycosylated flavonols that were essentially observed in the embryo. Epicatechin, procyanidins and an additional quercetin-rhamnoside-hexoside derivative were synthesized in large quantities during seed development, whereas quercetin-3-O-rhamnoside displayed two peaks of accumulation. Finally, 11 mutants affected in known structural or regulatory functions of the pathway and their three corresponding wild types were also studied. Flavonoid profiles of the mutants were consistent with previous predictions based on genetic and molecular data. In addition, they also revealed the presence of new products in seed and underlined the plasticity of this metabolic pathway in the mutants.

Flavonoids are secondary metabolites that accumulate in most plant seeds and are involved in physiological functions such as dormancy or viability. This review presents a current view of the genetic and biochemical control of flavonoid metabolism during seed development. It focuses mainly on proanthocyanidin accumulation in Arabidopsis, with comparisons to other related metabolic and regulatory pathways. These intricate networks and their fine-tuned regulation, once they are determined, should contribute to a better understanding of seed coat development and the control of PA and flavonol metabolism. In addition, flavonoids provide an interesting model to study various biological processes and metabolic and regulatory networks.

The Arabidopsis thaliana transparent testa10 (tt10) mutant exhibits a delay in developmentally determined browning of the seed coat, also called the testa. Seed coat browning is caused by the oxidation of flavonoids, particularly proanthocyanidins, which are polymers of flavan-3-ol subunits such as epicatechin and catechin. The tt10 mutant seeds accumulate more epicatechin monomers and more soluble proanthocyanidins than wild-type seeds. Moreover, intact testa cells of tt10 cannot trigger H2O2-independent browning in the presence of epicatechin and catechin, in contrast with wild-type cells. UV-visible light detection and mass spectrometry revealed that the major oxidation products obtained with epicatechin alone are yellow dimers called dehydrodiepicatechin A. These products differ from proanthocyanidins in the nature and position of their interflavan linkages. Flavonol composition was also affected in tt10 seeds, which exhibited a higher ratio of quercetin rhamnoside monomers versus dimers than wild-type seeds. We identified the TT10 gene by a candidate gene approach. TT10 encodes a protein with strong similarity to laccase-like polyphenol oxidases. It is expressed essentially in developing testa, where it colocalizes with the flavonoid end products proanthocyanidins and flavonols. Together, these data establish that TT10 is involved in the oxidative polymerization of flavonoids and functions as a laccase-type flavonoid oxidase.