The Madagascar's periwinkle is the model plant for studies of plant specialized metabolism and monoterpenoid indole alkaloids (MIAs), and an important source for the anticancer medicine vinblastine. ...The elucidation of entire 28-step biosynthesis of vinblastine allowed further investigations for the formation of other remarkably complex bioactive MIAs. In this study, we describe the discovery and characterization of vindolinine synthase, a Fe(II)/α-ketoglutarate-dependent (Fe/2OG) dioxygenase, that diverts assembly of tabersonine to vinblastine toward the formation of three alternatively cyclized MIAs: 19S-vindolinine, 19R-vindolinine, and venalstonine. Vindolinine synthase catalyzes a highly unusual, redox-neutral reaction to form a radical from dehydrosecodine, which is further cyclized by hydrolase 2 to form the three MIA isomers. We further show the biosynthesis of vindolinine epimers from tabersonine using hydrolase 2 catalyzed reverse cycloaddition. While the occurrence of vindolinines is rare in nature, the more widely found venalstonine derivatives are likely formed from similar redox-neutral reactions by homologous Fe/2OG dioxygenases.
Resveratrol is a stilbene with well-known health-promoting effects in humans that is produced constitutively or accumulates as a phytoalexin in several plant species including grape (Vitis sp.). ...Grape berries accumulate stilbenes in the exocarp as cis- and trans-isomers of resveratrol, together with their respective 3-O-monoglucosides. An enzyme glucosylating cis- and trans-resveratrol was purified to apparent homogeneity from Concord (Vitis labrusca) grape berries, and peptide sequencing associated it to an uncharacterized Vitis vinifera full-length clone (TC38971, tigr database). A corresponding gene from Vitis labrusca (VLRSgt) had 98% sequence identity to clone TC38971 and 92% sequence identity to a Vitis viniferap-hydroxybenzoic acid glucosyltransferase that produces glucose esters. The recombinant enzyme was active over a broad pH range (5.5-10), producing glucosides of stilbenes, flavonoids and coumarins at higher pH and glucose esters of several hydroxybenzoic and hydroxycinnamic acids at low pH. Vitis labrusca grape berries accumulated both stilbene glucosides and hydroxycinnamic acid glucose esters, consistent with the bi-functional role of VLRSgt in stilbene and hydroxycinnamic acid modification. While phylogenetic analysis of VLRSgt and other functionally characterized glucosyltransferases places it with other glucose ester-producing enzymes, the present results indicate broader biochemical activities for this class of enzymes.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Positron emission tomography with 11CCURB was recently developed to quantify fatty acid amide hydrolase (FAAH), the enzyme responsible for hydrolyzing the endocannabinoid anandamide. This study ...investigated the test–retest reliability of 11CCURB as well as its in vivo specificity and the validity of the kinetic model by using the highly specific FAAH inhibitor, PF-04457845. Five healthy volunteers completed test–retest 11CCURB scans 1 to 2 months apart and six subjects completed baseline and blocking scans on the same day after PF-04457845 (p.o.) administration (1, 4, or 20 mg; n = 2 each). The composite parameter γk3 (an index of FAAH activity, γ = K1/k2) was estimated using an irreversible two-tissue compartment model with plasma input function. There were no clinically observable responses to oral PF-04457845 or 11CCURB injection. Oral administration of PF-04457845 reduced 11CCURB binding to a homogeneous level at all three doses, with γk3 values decreased by ≥91%. Excellent reproducibility and good reliability (test–retest variability = 9%; intraclass correlation coefficient = 0.79) were observed across all regions of interest investigated. Our findings suggest that γk3/11CCURB is a reliable, highly sensitive, and selective tool to measure FAAH activity in human brain in vivo. Moreover, PF-04457845 is a highly potent FAAH inhibitor (>95% inhibition at 1 mg) in living human brain.
Full text
Available for:
NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Vinca minor is a herbaceous plant from the Apocynaceae family known to produce over 50 monoterpene indole alkaloids (MIAs). These include several biologically active MIAs that have a range of ...pharmaceutical activities. The present study shows that the MIAs, vincamine, akuammicine, minovincinine, lochnericine and vincadifformine tend to be secreted on V. minor leaf surfaces. A secretion mechanism of MIAs, previously described for Catharanthus roseus, appears to be mediated by a member (CrTPT2) of the pleiotropic drug resistance ABC transporter subfamily. The molecular cloning of an MIA transporter (VmTPT2/VmABCG1) that is predominantly expressed in V. minor leaves was functionally characterized in yeast and established it as an MIA efflux transporter. The similar function of VmTPT2/VmABCG1 to CrTPT2 increases the likelihood that this MIA transporter family may have co-evolved within members of Apocynaceae family to secrete selected MIAs and to regulate leaf MIA surface chemistry.
Display omitted
•V. minor secretes MIAs to the surface of leaves.•Secretion is mediated by an ABC transporter common to MIA accumulating plants.•Expression of this transporter is developmentally regulated.•VmTPT2 expressing yeast cells excrete MIAs into the media.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Roughly 30% of schizophrenia patients fail to respond to at least two antipsychotic trials. Psychosis has been traditionally considered to be poorly sensitive to psychotherapy. Nevertheless, there is ...increasing evidence that psychological interventions could be considered in treatment-resistant psychosis (TRP). Despite the relevance of the issue and the emerging neurobiological underpinnings, no systematic reviews have been published. Here, we show a systematic review of psychotherapy interventions in TRP patients of the last 25 years.
The MEDLINE/PubMed, ISI WEB of Knowledge, and Scopus databases were inquired from January 1, 1993, to August 1, 2018, for reports documenting augmentation or substitution with psychotherapy for treatment-resistant schizophrenia (TRS) and TRP patients. Quantitative data fetched by Randomized Controlled Trials (RCTs) were pooled for explorative meta-analysis.
Forty-two articles have been found. Cognitive behavioral therapy (CBT) was the most frequently recommended psychotherapy intervention for TRS (studies,
= 32, 76.2%), showing efficacy for general psychopathology and positive symptoms as documented by most of the studies, but with uncertain efficacy on negative symptoms. Other interventions showed similar results. The usefulness of group therapy was supported by the obtained evidence. Few studies focused on negative symptoms. Promising results were also reported for resistant early psychosis.
Measurement and publication bias due to the intrinsic limitations of the appraised original studies.
CBT, psychosocial intervention, supportive counseling, psychodynamic psychotherapy, and other psychological interventions can be recommended for clinical practice. More studies are needed, especially for non-CBT interventions and for all psychotherapies on negative symptoms.
The monoterpenoid indole alkaloids (MIAs) of Madagascar periwinkle (Catharanthus roseus) continue to be the most important source of natural drugs in chemotherapy treatments for a range of human ...cancers. These anticancer drugs are derived from the coupling of catharanthine and vindoline to yield powerful dimeric MIAs that prevent cell division. However the precise mechanisms for their assembly within plants remain obscure. Here we report that the complex development-, environment-, organ-, and cell-specific controls involved in expression of MIA pathways are coupled to secretory mechanisms that keep catharanthine and vindoline separated from each other in living plants. Although the entire production of catharanthine and vindoline occurs in young developing leaves, catharanthine accumulates in leaf wax exudates of leaves, whereas vindoline is found within leaf cells. The spatial separation of these two MIAs provides a biological explanation for the low levels of dimeric anticancer drugs found in the plant that result in their high cost of commercial production. The ability of catharanthine to inhibit the growth of fungal zoospores at physiological concentrations found on the leaf surface of Catharanthus leaves, as well as its insect toxicity, provide an additional biological role for its secretion. We anticipate that this discovery will trigger a broad search for plants that secrete alkaloids, the biological mechanisms involved in their secretion to the plant surface, and the ecological roles played by them.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
In recent years, several studies have investigated genetic polymorphisms of antipsychotic drug-metabolizing enzymes and receptors. However, most studies focused on drug response and very few have ...investigated the genetic influence on antipsychotic dosage. The aim of the present study is to test the association between antipsychotic dosages at genome-wide level. The current dosage of antipsychotic medications was collected from 79 schizophrenia patients. The dosage was standardized using three different methods: chlorpromazine equivalent (CPZe), defined daily dose (DDD), and percentage of maximum dose (PM %). The patients were then genotyped using the
Illumina HumanOmni2.5
-
8 BeadChip Kit
. All markers were screened for significance using linear regression, and the
p
values were visualized using a Manhattan plot. The genome-wide analysis showed that the top Single-Nucleotide Polymorphisms (SNPs) associated with dosage variation were rs981975 on chromosome 14 for CPZe, rs4470690 on chromosome 4 for PM %, and rs79323383 on chromosome 8 for DDD. However, no genome-wide significantly associated SNPs were identified. In this pilot sample, we found promising trends for pharmacodynamic targets associated with antipsychotic dosage. Therefore, studies combining large prescription databases may identify genetic predictors to adjust the dose of antipsychotic medication.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract Tardive dyskinesia (TD) is an involuntary movement disorder that can occur in up to 25% of patients receiving long-term first-generation antipsychotic treatment. Its etiology is unclear, but ...family studies suggest that genetic factors play an important role in contributing to risk for TD. The vesicular monoamine transporter 2 (VMAT2) is an interesting candidate for genetic studies of TD because it regulates the release of neurotransmitters implicated in TD, including dopamine, serotonin, and GABA. VMAT2 is also a target of tetrabenazine, a drug used in the treatment of hyperkinetic movement disorders, including TD. We examined nine single-nucleotide polymorphisms (SNPs) in the SLC18A2 gene that encodes VMAT2 for association with TD in our sample of chronic schizophrenia patients ( n = 217). We found a number of SNPs to be nominally associated with TD occurrence and the Abnormal Involuntary Movement Scale (AIMS), including the rs2015586 marker which was previously found associated with TD in the CATIE sample ( Tsai et al., 2010 ), as well as the rs363224 marker, with the low-expression AA genotype appearing to be protective against TD ( p = 0.005). We further found the rs363224 marker to interact with the putative functional D2 receptor rs6277 (C957T) polymorphism ( p = 0.001), supporting the dopamine hypothesis of TD. Pending further replication, VMAT2 may be considered a therapeutic target for the treatment and/or prevention of TD.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Tardive dyskinesia (TD) is a potentially irreversible movement disorder observed following long‐term antipsychotic exposure. Its cause is unknown; however, a genetic component has been supported by ...studies of affected families. Dysbindin‐1, encoded by the dystrobrevin‐binding protein 1 DTNBP1 gene, has been associated with schizophrenia and is potentially involved in dopamine neurotransmission through its regulation of dopamine release and dopamine D2 receptor recycling, making it a candidate for investigation in TD. We investigated common variants across the DTNBP1 gene in our schizophrenia/patients with schizoaffective disorder of European ancestry. We found a number of DTNBP1 three‐marker haplotypes to be associated with TD occurrence and TD severity (p < 0.05). These preliminary findings, if replicated in larger independent samples, would suggest that drugs targeting dysbindin‐1 may be an option in the prevention and treatment of TD.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Developed data-mining framework to study plant specialized metabolism.•Compared two next-generation sequencing technologies.•Assigned functional information to >800,000 transcripts from 20 plant ...species.•Described selection of gene candidates associated with six metabolic pathways.
Plants produce a vast array of specialized metabolites, many of which are used as pharmaceuticals, flavors, fragrances, and other high-value fine chemicals. However, most of these compounds occur in non-model plants for which genomic sequence information is not yet available. The production of a large amount of nucleotide sequence data using next-generation technologies is now relatively fast and cost-effective, especially when using the latest Roche-454 and Illumina sequencers with enhanced base-calling accuracy. To investigate specialized metabolite biosynthesis in non-model plants we have established a data-mining framework, employing next-generation sequencing and computational algorithms, to construct and analyze the transcriptomes of 75 non-model plants that produce compounds of interest for biotechnological applications. After sequence assembly an extensive annotation approach was applied to assign functional information to over 800,000 putative transcripts. The annotation is based on direct searches against public databases, including RefSeq and InterPro. Gene Ontology (GO), Enzyme Commission (EC) annotations and associated Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway maps are also collected. As a proof-of-concept, the selection of biosynthetic gene candidates associated with six specialized metabolic pathways is described. A web-based BLAST server has been established to allow public access to assembled transcriptome databases for all 75 plant species of the PhytoMetaSyn Project (www.phytometasyn.ca).
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
PDF
