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In JoVE (1)
Other Publications (11)
- Plant Physiology
- The Plant Cell
- Journal of Neurochemistry
- Analytical Biochemistry
- Plant Physiology
- Analytical Biochemistry
- Analytical Biochemistry
- Clinica Chimica Acta; International Journal of Clinical Chemistry
- Analytical and Bioanalytical Chemistry
- Genes & Nutrition
- Reproductive Biology and Endocrinology : RB&E
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Articles by Patricia Lam in JoVE
Uso de Arabidopsis mutantes eceriferum para Explorar Biossíntese Cutícula Vegetal
Lacey Samuels1, Allan DeBono1, Patricia Lam1, Miao Wen1, Reinhard Jetter1,2, Ljerka Kunst1
1Department of Botany, University of British Columbia - UBC, 2Department of Chemistry, University of British Columbia - UBC
A cutícula é uma planta que cobre waxy exterior sobre as plantas que tem um papel fundamental na conservação da água, mas também é uma importante barreira contra a entrada de microorganismos patogênicos. Neste vídeo, demonstramos a análise de mutantes de plantas cutícula identificados por abordagens frente e verso genética.
Other articles by Patricia Lam on PubMed
CER4 Encodes an Alcohol-forming Fatty Acyl-coenzyme A Reductase Involved in Cuticular Wax Production in Arabidopsis
Plant Physiology. Nov, 2006 | Pubmed ID: 16980563
A waxy cuticle that serves as a protective barrier against uncontrolled water loss and environmental damage coats the aerial surfaces of land plants. It is composed of a cutin polymer matrix and waxes. Cuticular waxes are complex mixtures of very-long-chain fatty acids and their derivatives. We report here the molecular cloning and characterization of CER4, a wax biosynthetic gene from Arabidopsis (Arabidopsis thaliana). Arabidopsis cer4 mutants exhibit major decreases in stem primary alcohols and wax esters, and slightly elevated levels of aldehydes, alkanes, secondary alcohols, and ketones. This phenotype suggested that CER4 encoded an alcohol-forming fatty acyl-coenzyme A reductase (FAR). We identified eight FAR-like genes in Arabidopsis that are highly related to an alcohol-forming FAR expressed in seeds of jojoba (Simmondsia chinensis). Molecular characterization of CER4 alleles and genomic complementation revealed that one of these eight genes, At4g33790, encoded the FAR required for cuticular wax production. Expression of CER4 cDNA in yeast (Saccharomyces cerevisiae) resulted in the accumulation of C24:0 and C26:0 primary alcohols. Fully functional green fluorescent protein-tagged CER4 protein was localized to the endoplasmic reticulum in yeast cells by confocal microscopy. Analysis of gene expression by reverse transcription-PCR indicated that CER4 was expressed in leaves, stems, flowers, siliques, and roots. Expression of a beta-glucuronidase reporter gene driven by the CER4 promoter in transgenic plants was detected in epidermal cells of leaves and stems, consistent with a dedicated role for CER4 in cuticular wax biosynthesis. CER4 was also expressed in all cell types in the elongation zone of young roots. These data indicate that CER4 is an alcohol-forming FAR that has specificity for very-long-chain fatty acids and is responsible for the synthesis of primary alcohols in the epidermal cells of aerial tissues and in roots.
A Core Subunit of the RNA-processing/degrading Exosome Specifically Influences Cuticular Wax Biosynthesis in Arabidopsis
The Plant Cell. Mar, 2007 | Pubmed ID: 17351114
The cuticle is an extracellular matrix composed of cutin polyester and waxes that covers aerial organs of land plants and protects them from environmental stresses. The Arabidopsis thaliana cer7 mutant exhibits reduced cuticular wax accumulation and contains considerably lower transcript levels of ECERIFERUM3/WAX2/YORE-YORE (CER3/WAX2/YRE), a key wax biosynthetic gene. We show here that CER7 protein is a putative 3'-5' exoribonuclease homologous to yeast Ribonuclease PH45 (RRP45p), a core subunit of the RNA processing and degrading exosome that controls the expression of CER3/WAX2/YRE. We propose that CER7 acts by degrading a specific mRNA species encoding a negative regulator of CER3/WAX2/YRE transcription. A second RRP45p homolog found in Arabidopsis, designated At RRP45a, is partially functionally redundant with CER7, and complete loss of RRP45 function in Arabidopsis is lethal. To our knowledge, CER7 is currently the only example of a core exosomal subunit specifically influencing a cellular process.
Activation of Recombinant Human TRPV1 Receptors Expressed in SH-SY5Y Human Neuroblastoma Cells Increases [Ca(2+)](i), Initiates Neurotransmitter Release and Promotes Delayed Cell Death
Journal of Neurochemistry. Aug, 2007 | Pubmed ID: 17442052
The transient receptor potential (TRP) vanilloid receptor subtype 1 (TRPV1) is a ligand-gated, Ca(2+)-permeable ion channel in the TRP superfamily of channels. We report the establishment of the first neuronal model expressing recombinant human TRPV1 (SH-SY5Y(hTRPV1)). SH-SY5Y human neuroblastoma cells were stably transfected with hTRPV1 using the Amaxa Biosystem (hTRPV1 in pIREShyg2 with hygromycin selection). Capsaicin, olvanil, resiniferatoxin and the endocannabinoid anandamide increased [Ca(2+)](i) with potency (EC(50)) values of 2.9 nmol/L, 34.7 nmol/L, 0.9 nmol/L and 4.6 micromol/L, respectively. The putative endovanilloid N-arachidonoyl-dopamine increased [Ca(2+)](i) but this response did not reach a maximum. Capsaicin, anandamide, resiniferatoxin and olvanil mediated increases in [Ca(2+)](i) were inhibited by the TRPV1 antagonists capsazepine and iodo-resiniferatoxin with potencies (K(B)) of approximately 70 nmol/L and 2 nmol/L, respectively. Capsaicin stimulated the release of pre-labelled [(3)H]noradrenaline from monolayers of SH-SY5Y(hTRPV1) cells with an EC(50) of 0.6 nmol/L indicating amplification between [Ca(2+)](i) and release. In a perfusion system, we simultaneously measured [(3)H]noradrenaline release and [Ca(2+)](i) and observed that increased [Ca(2+)](i) preceded transmitter release. Capsaicin treatment also produced a cytotoxic response (EC(50) 155 nmol/L) that was antagonist-sensitive and mirrored the [Ca(2+)](I) response. This model displays pharmacology consistent with TRPV1 heterologously expressed in standard non-neuronal cells and native neuronal cultures. The advantage of SH-SY5Y(hTRPV1) is the ability of hTRPV1 to couple to neuronal biochemical machinery and produce large quantities of cells.
Ultra Performance Liquid Chromatography Tandem Mass Spectrometry Method for the Measurement of Anandamide in Human Plasma
Analytical Biochemistry. Sep, 2008 | Pubmed ID: 18555789
Anandamide (N-arachidonoylethanolamine, AEA) is an endocannabinoid present in human plasma that is associated with several physiological functions and disease states. Significant variability in AEA plasma concentrations has been reported between studies, because quantification of AEA is fraught with methodological difficulties. A rapid, highly sensitive, robust, specific, and highly reproducible ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method is described here for the analysis of AEA in human plasma. This fully validated method using octa-deuterated AEA (AEA-d8) as an internal standard represents an improvement over previous analyses in terms of run time (4 min), limit of detection (0.055 fmol on column, 18.75 fmol/ml plasma), precision (relative standard deviations of 3.7, 3.9, and 4.8% for 1.66, 6.65, and 133 fmol on column), and accuracy (97.5-104.5%). AEA analysis was linear over the range 0.23 to 19 nM (1.66 to 133 fmol on column). To demonstrate the usefulness of this method for the measurement of AEA levels in clinical samples, plasma samples obtained from female volunteers at different stages of the menstrual cycle and pregnant women were assayed. Plasma AEA concentrations were significantly (P=0.0078) lower in the luteal phase of the menstrual cycle compared to the follicular phase. In pregnancy, the concentrations were lowest in the first and second trimesters with levels comparable to those observed in the luteal phase of the menstrual cycle and modestly increased in the third trimester. The highest plasma AEA levels were observed in women in active labour, and these were significantly (P=0.0147) higher than those observed in women at term but not in active labour. Postmenopausal women had AEA concentrations comparable to levels observed during the luteal phase of premenopausal women and were significantly (P=0.0389) lower than AEA plasma concentrations obtained during the follicular phase. The sensitivity and precision of the validated method described here suggests that this method is suitable for the analysis of AEA in clinical samples and may be utilised for the investigation of biomatrices containing limited amounts of AEA.
Identification of the Wax Ester Synthase/acyl-coenzyme A: Diacylglycerol Acyltransferase WSD1 Required for Stem Wax Ester Biosynthesis in Arabidopsis
Plant Physiology. Sep, 2008 | Pubmed ID: 18621978
Wax esters are neutral lipids composed of aliphatic alcohols and acids, with both moieties usually long-chain (C(16) and C(18)) or very-long-chain (C(20) and longer) carbon structures. They have diverse biological functions in bacteria, insects, mammals, and terrestrial plants and are also important substrates for a variety of industrial applications. In plants, wax esters are mostly found in the cuticles coating the primary shoot surfaces, but they also accumulate to high concentrations in the seed oils of a few plant species, including jojoba (Simmondsia chinensis), a desert shrub that is the major commercial source of these compounds. Here, we report the identification and characterization of WSD1, a member of the bifunctional wax ester synthase/diacylglycerol acyltransferase gene family, which plays a key role in wax ester synthesis in Arabidopsis (Arabidopsis thaliana) stems, as first evidenced by severely reduced wax ester levels of in the stem wax of wsd1 mutants. In vitro assays using protein extracts from Escherichia coli expressing WSD1 showed that this enzyme has a high level of wax synthase activity and approximately 10-fold lower level of diacylglycerol acyltransferase activity. Expression of the WSD1 gene in Saccharomyces cerevisiae resulted in the accumulation of wax esters, but not triacylglycerol, indicating that WSD1 predominantly functions as a wax synthase. Analyses of WSD1 expression revealed that this gene is transcribed in flowers, top parts of stems, and leaves. Fully functional yellow fluorescent protein-tagged WSD1 protein was localized to the endoplasmic reticulum, demonstrating that biosynthesis of wax esters, the final products of the alcohol-forming pathway, occurs in this subcellular compartment.
A Solid-phase Method for the Extraction and Measurement of Anandamide from Multiple Human Biomatrices
Analytical Biochemistry. Jan, 2009 | Pubmed ID: 18823934
N-Arachidonoylethanolamine (AEA, anandamide) was the first endocannabinoid to be identified and has since become associated with the mediation of several physiological functions and disease states. AEA has been isolated from numerous tissues and biofluids, in the low nanomolar range, using lipid extraction techniques with organic solvents. These techniques require the drying down of relatively large volumes of solvents, making them unsuitable for high-throughput analysis. Here we describe a solid-phase extraction (SPE) method for the investigation of AEA concentrations in human plasma, serum, milk, urine, amniotic fluid, peritoneal fluid, saliva, follicular fluid, and fluid from an ovarian cyst. AEA was detected in serum and plasma from blood isolated from 20 adult women (means+/-standard deviations: 0.68+/-0.29 and 0.64+/-0.28 nM, respectively), from pregnant women at term (1.37+/-0.42 nM), and from umbilical vein (1.26+/-0.33 nM) and umbilical artery (1.14+/-0.35nM), in milk (0.12+/-0.05 nM) and from amniotic (0.03+/-0.02 nM), peritoneal (0.93+/-0.27 nM), follicular (1.17+/-0.51 nM), and ovarian cyst (0.32+/-0.01 nM) fluids. AEA was undetectable in saliva and urine. The 60% AEA extraction efficiency achieved with SPE from plasma was superior to the 19% efficiency achieved using the existing organic solvent extraction method. Limits of quantification and detection for AEA were also improved dramatically using SPE (8 and 4 fmol/ml) compared with organic extraction (25 and 18.75 fmol/ml plasma). These improvements allow the use of smaller plasma samples with SPE. Intra- and interday variability were comparable, and the mean AEA concentration of pooled plasma samples (1.18 nM, n=15) was identical with the two techniques. Similarly, when 56 plasma samples from laboring and nonlaboring women were analyzed using both techniques, no extraction method-dependent differences were observed. Consequently, we provide evidence for a robust SPE technique for the extraction of AEA from biomatrices to replace the existing liquid extraction methods, with the SPE technique being superior in terms of speed, extraction efficiency, and sample size required.
Anandamide Levels in Human Female Reproductive Tissues: Solid-phase Extraction and Measurement by Ultraperformance Liquid Chromatography Tandem Mass Spectrometry
Analytical Biochemistry. May, 2010 | Pubmed ID: 20026294
Anandamide (N-arachidonoylethanolamide), a bioactive lipid, is reported to play a role in pregnancy maintenance and parturition. Our aims were to (1) evaluate AEA levels at the human maternal:fetal interface and (2) validate the use of solid-phase extraction of AEA from tissues. AEA was analyzed in cord and maternal blood, amniotic fluid, placenta, and fetal membranes collected during Caesarean section (n=14). Extraction efficiencies were 42 and 36% for the placenta and the fetal membranes, respectively. Tissue AEA was quantified using an isotope-dilution method and UPLC-ESI-MS/MS giving intra- and inter-day variability for tissues spiked with 0.2, 1, and 5pmol/g AEA of less than 12%. Accuracy for these spiked samples was between 95% and 103% for fetal membranes and between 99% and 114% for placenta. Mean AEA concentrations were 2.72 + or - 1.04 pmol/g for placenta and 1.19 + or - 0.68 pmol/g for fetal membranes, and 0.93 + or - 0.28, 0.88 + or - 0.33, 0.77 + or - 0.30, and 0.06 + or - 0.04nM for maternal, umbilical vein, and umbilical artery plasma and amniotic fluid. Higher AEA concentrations were found in placenta compared to fetal membranes (P<0.0001), in umbilical vein compared with umbilical artery (P=0.0015), and in plasma from maternal circulation compared with umbilical artery (P=0.0152). The relevance of these changes in AEA concentrations at the maternal:fetal interface requires further investigation.
Clinica Chimica Acta; International Journal of Clinical Chemistry. Jul, 2010 | Pubmed ID: 20302856
Acylethanolamides such as anandamide (AEA), and monoacylglycerols like 2-arachidonoylglycerol are endocannabinoids that bind to cannabinoid, vanilloid and peroxisome proliferator-activated receptors. These compounds, their various receptors, the purported membrane transporter(s), and related enzymes that synthesize and degrade them are collectively referred to as the "endocannabinoid system (ECS)". Poorly defined cellular and molecular mechanisms control the biological actions of the ECS. Over the last decade evidence has been emerging to suggest that the ECS plays a significant role in various aspects of human reproduction. In this review, we summarize our current understanding of this role especially the involvement of AEA and related ECS elements in regulating oogenesis, embryo oviductal transport, blastocyst implantation, placental development and pregnancy outcomes, and sperm survival, motility, capacitation and acrosome reaction. Additionally, the possibility that plasma and tissue AEA and other cannabinoids may represent reliable diagnostic markers of natural and assisted reproduction and pregnancy outcomes in women will be discussed.
Simultaneous Measurement of Three N-acylethanolamides in Human Bio-matrices Using Ultra Performance Liquid Chromatography-tandem Mass Spectrometry
Analytical and Bioanalytical Chemistry. Nov, 2010 | Pubmed ID: 20835819
Endocannabinoids including N-acylethanolamides (NAEs) are a family of lipid-related signaling molecules implicated in many physiological and disease states which elicit their activities via the cannabinoid receptors. Anandamide (N-arachidonoylethanolamine, AEA) is the most characterized endocannabinoid and has been detected in many tissues and bio-fluids including human plasma and the central nervous system. The endocannabinoid-like NAEs, oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) are described as entourage compounds because they illicit similar physiological effects to AEA but have little or no affinity for cannabinoid receptors. As entourage compounds, levels of these NAEs can greatly influence the efficacy of AEA yet there are few studies which measure these compounds in bio-fluids. Here we describe a rapid, highly sensitive, specific and highly reproducible ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the analysis of AEA, OEA, and PEA in human bio-fluids including plasma, serum, breast milk, and amniotic fluids. This validated method using deuterated (AEA-d(8), OEA-d(2), and PEA-d(4)) internal standards, represents an improvement over previous analyses in terms of run time (4 min), limit of detection (0.9 fmol on column for AEA and PEA and 4.4 fmol on column for OEA), precision (relative standard deviations of peak areas: 3.1% (AEA), 2.9% (OEA), and 5.4% (PEA) for 133 fmol on column) and accuracy (95.1-104.9%). The sensitivity and precision of the validated method described here suggests that this method is suitable for the analysis of AEA, OEA, and PEA in clinical samples and may be utilized for the investigation of bio-matrices containing limited amounts of NAEs.
Associations Between Functional Polymorphisms in Antioxidant Defense Genes and Urinary Oxidative Stress Biomarkers in Healthy, Premenopausal Women
Genes & Nutrition. Nov, 2011 | Pubmed ID: 22068340
Functional polymorphisms in endogenous antioxidant defense genes including manganese superoxide dismutase (MnSOD), catalase (CAT), and glutathione peroxidase (GPX-1) have been linked with risk of cancer at multiple sites. Although it is presumed that these germline variants impact disease risk by altering the host's ability to detoxify mutagenic reactive oxygen species, very few studies have directly examined this hypothesis. Concentrations of 8-isoprostane F2α (8-iso-PGF2α) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxoxdG)-sensitive indicators of lipid peroxidation and DNA oxidation, respectively-were measured in 24-h urine samples obtained from 93 healthy, premenopausal women participating in a dietary intervention trial. In addition, DNA was extracted from blood for genotyping of MnSOD Val16Ala, CAT-262 C > T, and GPX1 Pro198Leu genotypes by Taqman assay. Although geometric mean concentrations of 8-iso-PGF2(α) and 8-oxoxdG varied across several study characteristics including race, education level, body mass index, and serum antioxidant levels, there was little evidence that these biomarkers differed across any of the examined genotypes. In summary, functional polymorphisms in endogenous antioxidant defense genes do not appear to be strongly associated with systemic oxidative stress levels in young, healthy women.
Modulation of the Endocannabinoid System in Viable and Non-viable First Trimester Pregnancies by Pregnancy-related Hormones
Reproductive Biology and Endocrinology : RB&E. 2011 | Pubmed ID: 22126420