JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Virus-Induced Alterations in Primary Metabolism Modulate Susceptibility to Tobacco rattle virus in Arabidopsis.
Plant Physiol.
PUBLISHED: 11-01-2014
Show Abstract
Hide Abstract
During compatible virus infections, plants respond by reprogramming gene expression and metabolite accumulation. While gene expression studies are profuse, our knowledge of the metabolic changes that occur in the presence of the virus is limited. Here we combine gene expression and metabolite profiling in Arabidopsis thaliana infected with Tobacco rattle virus (TRV) in order to investigate the influence of primary metabolism on virus infection. Our results revealed that primary metabolism is reconfigured in many ways during TRV infection, as reflected by significant changes in the levels of sugars and amino acids. Multivariate data analysis revealed that these alterations were particularly conspicuous at the time points of maximal accumulation of TRV although infection time was the dominant source of variance during the process. Furthermore, TRV caused changes in lipid and fatty acid (FA) composition in infected leaves. We found that several Arabidopsis mutants deficient in branched-chain amino acid catabolism or fatty acid metabolism possessed altered susceptibility to TRV. Finally, we showed that increments in the putrescine content in TRV-infected plants correlated with enhanced tolerance to freezing stress in TRV-infected plants, and that impairment of putrescine biosynthesis promoted virus multiplication. Our results thus provide an interesting overview for a better understanding of the relationship between primary metabolism and virus infection.
Related JoVE Video
Polymethacrylate monoliths with immobilized poly-3-mercaptopropyl methylsiloxane film for high-coverage surface functionalization by thiol-ene click reaction.
J Chromatogr A
PUBLISHED: 08-19-2014
Show Abstract
Hide Abstract
In this work, new polythiol-functionalized macroporous monolithic polymethacrylate-polysiloxane composite materials are presented which can be useful substrates for highly efficient immobilization of (chiral) catalysts, chromatographic ligands, and other functional moieties by thiol-ene click reaction. Poly(glycidyl methacrylate-co-ethylene dimethacrylate) (poly(GMA-co-EDMA)) monoliths were coated with a poly-3-mercaptopropyl methylsiloxane (PMPMS) film and subsequently the polymer was covalently immobilized by formation of crosslinks via nucleophilic substitution reaction with pendent 2,3-epoxypropyl groups on the monolith surface. This monolith, though, showed similar levels of surface coverage as a reference monolith obtained by opening of the epoxide groups with sodium hydrogen sulfide. However, a 3-step functionalization by amination of the epoxy monolith, followed by its vinylation with allylglycidyl ether and subsequent thiolation by coating of a thin polythiol (PMPMS) film and crosslinking by click reaction furnished a monolith with more than 2-fold elevated thiol coverage. Its further functionalization with a clickable chiral quinine carbamate selector clearly documented the benefit of highly dense thiol surfaces for such reactions and synthesis of functional materials with proper ligand loadings. The new monoliths were chromatographically tested in capillary electrochromatography mode using N-3,5-dinitrobenzoyl-leucine as chiral probe and the capillary column with the monolith having the highest selector coverage, produced from the precursor with the most thiols on the surface, showed the largest separation factor. By performic acid oxidation the surface characteristic could be tuned and strongly altered due to a delicate balance of enantioselective and non-specific interactions.
Related JoVE Video
Interplay between plasmid-mediated and chromosomal-mediated fluoroquinolone resistance and bacterial fitness in Escherichia coli.
J. Antimicrob. Chemother.
PUBLISHED: 08-19-2014
Show Abstract
Hide Abstract
The aim of this study was to analyse the interplay among plasmid-mediated qnr genes, alone or in combination with multiple chromosomal-mediated fluoroquinolone (FQ) resistance determinants, susceptibility to FQs and bacterial fitness in an isogenic Escherichia coli collection.
Related JoVE Video
Glycemic and lipid metabolic disorders in diabetic and non-diabetic patients bmi < 35 or > 35 before gastric bypass.
Nutr Hosp
PUBLISHED: 06-22-2014
Show Abstract
Hide Abstract
Obesity and diabetes are diseases with high prevalence worldwide. There is currently no effective medical treatment for combat the weight gain. It is precursor of diseases such as diabetes or metabolic syndrome. It is necessary to know if weight gain has cumulative effects on the glycemic and lipid metabolism as precursors of complications or comorbidities.
Related JoVE Video
Metabolic disorders of liver and iron in diabetic and non-diabetic patients BMI < 35 or > 35 before gastric bypass.
Nutr Hosp
PUBLISHED: 06-22-2014
Show Abstract
Hide Abstract
The presence of abnormalities in the metabolic pathways of iron and liver functioning can produce insulin resistance or metabolic syndrome. Therefore, it is important to examine those alterations that may lead to the development of diseases. Nutritional status is another important factor that is intimately linked to diabetes and obesity.
Related JoVE Video
UV-polymerized butyl methacrylate monoliths with embedded carboxylic single-walled carbon nanotubes for CEC applications.
Anal Bioanal Chem
PUBLISHED: 06-05-2014
Show Abstract
Hide Abstract
The preparation of polymeric monoliths with embedded carboxy-modified single-walled carbon nanotubes (c-SWNTs) and their use for capillary electrochromatography (CEC) is described. Carbon nanotube composites were obtained by preparing a polymerization mixture in the presence of increasing c-SWNT concentrations, followed by UV initiation. The novel stationary phases were studied by optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Using short UV-polymerization times, the optimized porogenic solvent (a binary mixture of 1,4-butanediol and 2-propanol) gave rise to polymeric beds with homogenously dispersed embedded c-SWNTs. The CEC features of these monoliths were evaluated using polycyclic aromatic hydrocarbons (PAHs), non-steroidal anti-inflammatory drugs (NSAIDs) and chiral compounds. The monolith prepared in the presence of c-SWNTs showed enhanced resolution of the text mixtures, including a remarkable capability to separate enantiomers.
Related JoVE Video
Insulin drives glucose-dependent insulinotropic peptide expression via glucose-dependent regulation of FoxO1 and LEF1/?-catenin.
Biochim. Biophys. Acta
PUBLISHED: 04-27-2014
Show Abstract
Hide Abstract
Minutes after ingestion of fat or carbohydrates, vesicles stored in enteroendocrine cells release their content of incretin peptide hormones that, together with absorbed glucose, enhance insulin secretion by beta-pancreatic cells. Freshly-made incretins must therefore be packed into new vesicles in anticipation of the next meal with cells adjusting new incretin production to be proportional to the level of previous insulin release and absorbed blood glucose. Here we show that insulin stimulates the expression of the major human incretin, glucose-dependent insulinotropic peptide (GIP) in enteroendocrine cells but requires glucose to do it. Akt-dependent release of FoxO1 and glucose-dependent binding of LEF1/?-catenin mediate induction of Gip expression while insulin-induced phosphorylation of ?-catenin does not alter its localization or transcriptional activity in enteroendocrine cells. Our results reveal a glucose-regulated feedback loop at the entero-insular axis, where glucose levels determine basal and insulin-induced Gip expression; GIP stimulation of insulin release, physiologically ensures a fine control of glucose homeostasis. How enteroendocrine cells adjust incretin production to replace incretin stores for future use is a key issue because GIP malfunction is linked to all forms of diabetes.
Related JoVE Video
Fast simultaneous determination of prominent polyphenols in vegetables and fruits by reversed phase liquid chromatography using a fused-core column.
Food Chem
PUBLISHED: 04-09-2014
Show Abstract
Hide Abstract
A reversed-phase high-performance liquid chromatography method with photodiode array detection has been developed enabling the joint determination of 17 prominent flavonoids and phenolic acids in vegetables and fruits. A multi-segmented gradient program using a fused-core column for the separation of several phenolic classes (phenolic acids and flavonoids) has been optimised. The influence of extraction conditions (sample freeze-drying, ultrasound extraction, solvent composition and extraction time) has been also optimised using response surface methodology with tomato samples as a model. Complete recoveries (76-108%) were obtained for the phenolic compounds present in tomato. The developed method provided satisfactory repeatability in terms of peak area (RSD<2.9%) and retention time (RSD<0.2%) both for standards and real samples. Detection limits ranged between 3 and 44?gkg(-1) for the detected polyphenols. This method is recommended for routine analysis of large number of samples typical of production quality systems or plant breeding programs.
Related JoVE Video
Lactococcus garvieae carries a chromosomally encoded pentapeptide repeat protein that confers reduced susceptibility to quinolones in Escherichia coli producing a cytotoxic effect.
Res. Microbiol.
PUBLISHED: 03-17-2014
Show Abstract
Hide Abstract
This study characterises a chromosomal gene of Lactococcus garvieae encoding a pentapeptide repeat protein designated as LgaQnr. This gene has been implicated in reduced susceptibility to quinolones in this bacterium, which is of relevance to both veterinary and human medicine. All of the L. garvieae isolates analysed were positive for the lgaqnr gene. The expression of lgaqnr in Escherichia coli reduced the susceptibility to quinolones, producing an adverse effect. The reduced susceptibility to ciprofloxacin was 16-fold in E. coli ATCC 25922 and 32-fold in E. coli DH10B, compared to the control strains. The minimum inhibitory concentration of nalidixic acid was also increased 4 or 5-fold. The effect of the expression of lgaqnr in E. coli was investigated by electron microscopy and was observed to affect the structure of the cell and the inner membrane of the recombinant cells.
Related JoVE Video
Mucositis care in acute leukemia and non-Hodgkin lymphoma patients undergoing high-dose chemotherapy.
Support Care Cancer
PUBLISHED: 03-04-2014
Show Abstract
Hide Abstract
This study intends to provide new insights into the incidence and care of mucositis by the epidemiological characterization of patients with hematological malignancy treated at our institution. It also aims to understand the effectiveness of several treatments used.
Related JoVE Video
Role of sulfonation in the stability, reactivity, and selectivity of poly(ether imide) used to develop ion exchange membranes: DFT study with application to fuel cells.
J Mol Model
PUBLISHED: 03-03-2014
Show Abstract
Hide Abstract
The design of polymer electrolyte membranes for fuel cells must satisfy two equally important fundamental principles: optimization of the reactivity and the selectivity in order to improve the ion transport properties of the membrane as well as its long-term stability in the hydrated state at high temperature (above 100 °C). A study utilizing density functional theory (DFT) to elucidate the effect of the degree of sulfonation on the chemical stability, reactivity, and selectivity of poly(ether imide) (PEI), which allows the ionic transport properties of the membrane to be predicted, is reported here. Sulfonated poly(ether imide) (SPEI) structures with (-SO3H) n (n?=?1-6) groups were built and optimized in order to calculate the above properties as functions of the number of sulfonyl groups. A comparative study demonstrated that the SPEI with four sulfonyl groups in its backbone is the polymer with the properties best suited for use in fuel cells.
Related JoVE Video
Efficient extraction of olive pulp and stone proteins by using an enzyme-assisted method.
J. Food Sci.
PUBLISHED: 01-21-2014
Show Abstract
Hide Abstract
An efficient protein extraction protocol for proteins from olive pulp and stone by using enzymes was developed. For this purpose, different parameters that affect the extraction process, such as enzyme type and content, pH, and extraction temperature and time, were tested. The influence of these factors on protein recovery was examined using the standard Bradford assay, while the extracted proteins were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The best extraction conditions were achieved at pH 7.0 and 5% (v/v) Palatase® 20000 L (lipase) for pulp and Lecitase® Ultra (phospholipase) for stone proteins. The optimal extraction temperature and time were 30 and 40 °C for 15 min for pulp and stone tissues, respectively. Under these conditions, several protein extracts coming from olive fruits of different genetic variety were analyzed, their profiles being compared by SDS-PAGE. The developed enzyme-assisted extraction method showed faster extraction, higher recovery, and reduced solvent usage than the nonenzymatic methods previously described in the literature. In the case of stone proteins, different electrophoretic profiles and band intensities were obtained that could be helpful to distinguish samples according to their genetic variety.
Related JoVE Video
The evolutionary conserved oil body associated protein OBAP1 participates in the regulation of oil body size.
Plant Physiol.
PUBLISHED: 01-09-2014
Show Abstract
Hide Abstract
A transcriptomic approach has been used to identify genes predominantly expressed in maize (Zea mays) scutellum during maturation. One of the identified genes is oil body associated protein1 (obap1), which is transcribed during seed maturation predominantly in the scutellum, and its expression decreases rapidly after germination. Proteins similar to OBAP1 are present in all plants, including primitive plants and mosses, and in some fungi and bacteria. In plants, obap genes are divided in two subfamilies. Arabidopsis (Arabidopsis thaliana) genome contains five genes coding for OBAP proteins. Arabidopsis OBAP1a protein is accumulated during seed maturation and disappears after germination. Agroinfiltration of tobacco (Nicotiana benthamiana) epidermal leaf cells with fusions of OBAP1 to yellow fluorescent protein and immunogold labeling of embryo transmission electron microscopy sections showed that OBAP1 protein is mainly localized in the surface of the oil bodies. OBAP1 protein was detected in the oil body cellular fraction of Arabidopsis embryos. Deletion analyses demonstrate that the most hydrophilic part of the protein is responsible for the oil body localization, which suggests an indirect interaction of OBAP1 with other proteins in the oil body surface. An Arabidopsis mutant with a transfer DNA inserted in the second exon of the obap1a gene and an RNA interference line against the same gene showed a decrease in the germination rate, a decrease in seed oil content, and changes in fatty acid composition, and their embryos have few, big, and irregular oil bodies compared with the wild type. Taken together, our findings suggest that OBAP1 protein is involved in the stability of oil bodies.
Related JoVE Video
Classification of olive leaves and pulps according to their cultivar by using protein profiles established by capillary gel electrophoresis.
Anal Bioanal Chem
PUBLISHED: 01-04-2014
Show Abstract
Hide Abstract
A method to classify olive leaves and pulps according to their cultivar using protein profiles obtained by capillary gel electrophoresis (CGE) has been developed. For this purpose, proteins were extracted using an enzyme-assisted method, which provided higher protein recoveries than other previously described methods. Ten and nine common peaks, for leaf and pulp samples, respectively, were identified in the 12 cultivars studied in this work. In addition, and using linear discriminant analysis of the CGE data, olive leaf and pulp samples belonging to 12 cultivars from different Spanish regions were correctly classified with an excellent resolution among all the categories, which demonstrated that protein profiles were characteristic of each cultivar.
Related JoVE Video
Chemical analysis and antioxidant activity of the essential oils of three Piperaceae species growing in the central region of Cuba.
Nat Prod Commun
PUBLISHED: 11-27-2013
Show Abstract
Hide Abstract
The present study describes the phytochemical profile and antioxidant activity of the essential oils of three Piperaceae species collected in the central region of Cuba. The essential oils of Piper aduncum, P. auritum and P. umbellatum leaves, obtained by hydrodistillation, were analyzed by gas chromatography-mass spectrometry. The main components of P. aduncum oil were piperitone (34%), camphor (17.1%), camphene (10.9%), 1,8-cineol (8.7%) and viridiflorol (7.4%), whereas that of P. auritum and P. umbellatum was safrole (71.8 and 26.4%, respectively). The antioxidant properties of the essential oils were also evaluated using several assays for radical scavenging ability (DPPH test and reducing power) and inhibition of lipid oxidation (ferric thiocyanate method and evaluation against Cucurbita seed oil by peroxide, thiobarbituric acid and p-anisidine methods). P. auritum showed the strongest antioxidant activity among the Piper species investigated, but lower than those of butylated hydroxyanisol and propyl gallate.
Related JoVE Video
Effectiveness of spirometry as a motivational tool for smoking cessation: a clinical trial, the ESPIMOAT study.
BMC Fam Pract
PUBLISHED: 11-06-2013
Show Abstract
Hide Abstract
Smoking is the main preventable cause of morbidity and mortality in our region, it being the main causative agent of chronic obstructive pulmonary disease. There still is no consensus on the use of spirometry as a strategy for smoking cessation, given that there is insufficient scientific evidence from high quality studies to recommend the use of this technique.
Related JoVE Video
A new link between diabetes and cancer: enhanced WNT/?-catenin signaling by high glucose.
J. Mol. Endocrinol.
PUBLISHED: 09-20-2013
Show Abstract
Hide Abstract
Extensive epidemiological studies suggest that the diabetic population is at higher risk of site-specific cancers. The diabetes-cancer link has been hypothesized to rely on various hormonal (insulin, IGF1, adipokines), immunological (inflammation), or metabolic (hyperglycemia) characteristics of the disease and even on certain treatments. Inflammation may have an important but incompletely understood role. As a growth factor, insulin directly, or indirectly through IGF1, has been considered the major link between diabetes and cancer, while high glucose has been considered as a subordinate cause. Here we discuss the evidence that supports a role for insulin/IGF1 in general in cancer, and the mechanism by which hyperglycemia may enhance the appearance, growth and survival of diabetes-associated cancers. High glucose triggers several direct and indirect mechanisms that cooperate to promote cancer cell proliferation, migration, invasion and immunological escape. In particular, high glucose enhancement of WNT/?-catenin signaling in cancer cells promotes proliferation, survival and senescence bypass, and represents a previously unrecognized direct mechanism linking diabetes-associated hyperglycemia to cancer. Increased glucose uptake is a hallmark of tumor cells and may ensure enhanced WNT signaling for continuous proliferation. Mechanistically, high glucose unbalances acetylation through increased p300 acetyl transferase and decreased sirtuin 1 deacetylase activity, leading to ?-catenin acetylation at lysine K354, a requirement for nuclear accumulation and transcriptional activation of WNT-target genes. The impact of high glucose on ?-catenin illustrates the remodeling of cancer-associated signaling pathways by metabolites. Metabolic remodeling of cancer-associated signaling will receive much research attention in the coming years. Future epidemiological studies may be guided and complemented by the identification of these metabolic interplays. Together, these studies should lead to the development of new preventive strategies for diabetes-associated cancers.
Related JoVE Video
Synchronized gradient elution in capillary liquid chromatography.
J Chromatogr A
PUBLISHED: 08-02-2013
Show Abstract
Hide Abstract
The synchronization of injection valve operation and gradient elution in capillary liquid chromatography (cHPLC) is studied. Focus is placed on the cHPLC systems which rely on the splitting of a primary flow to provide the much smaller secondary flow required at the injection device and analytical column. Owing to the tiny secondary flow rates, synchronization is necessary to achieve proper optimization of gradient elution methods. Otherwise, there is a risk of having the analytes totally or partially eluted in the initial isocratic conditions, and there is no control on the actual gradient profile reaching the column. Synchronization is first achieved by switching back the valve to bypass after injection. This is important to save time, and to avoid the gradient slope to be reduced by mixing within the internal volume of the injector (a 47% of slope reduction, in the conditions used in this work). Valve switching to bypass should be produced immediately after the arrival of the end of the sample plug to the valve (tV). Fine system synchronization is further achieved by starting the gradient at the match time (tM), which is the time required to match the arrival of both the gradient front and the end of the sample plug to the valve, and therefore also to the column inlet. Synchronization of these two events requires starting the gradient either before or even after the injection, thus to prevent a late or an early arrival of the gradient front to the injection valve, respectively. Owing to their dependence with the backpressure, both tV and tM should be measured in the presence of the column at the initial gradient conditions. Simple experiments designed to measure tV and tM are described. With synchronization according to the techniques described in this work, control on the real gradient elution conditions at the column location is maintained, the analysis time is reduced and efficiency improves. The effects of synchronization are illustrated by injecting a mixture of alkylbenzenes. At 1?L min(-1), valve switching to bypass reduced analysis time from ca. 36 to 12min (butylbenzene), and improved peak symmetry (from 2.00 to 0.94 for methylbenzene) and efficiency (the average apparent plate count increased approximately 60%). Synchronization according to the match time further improved efficiency (approximately, up to 120%).
Related JoVE Video
Pathogen and Circadian Controlled 1 (PCC1) regulates polar lipid content, ABA-related responses, and pathogen defence in Arabidopsis thaliana.
J. Exp. Bot.
PUBLISHED: 07-05-2013
Show Abstract
Hide Abstract
Pathogen and Circadian Controlled 1 (PCC1) was previously characterized as a regulator of defence against pathogens and stress-activated transition to flowering. Plants expressing an RNA interference construct for the PCC1 gene (iPCC1 plants) showed a pleiotropic phenotype. They were hypersensitive to abscisic acid (ABA) as shown by reduced germination potential and seedling establishment, as well as reduced stomatal aperture and main root length in ABA-supplemented media. In addition, iPCC1 plants displayed alterations in polar lipid contents and their corresponding fatty acids. Importantly, a significant reduction in the content of phosphatidylinositol (PI) was observed in iPCC1 leaves when compared with wild-type plants. A trend in reduced levels of 18:0 and increased levels of 18:2 and particularly 18:3 was also detected in several classes of polar lipids. The enhanced ABA-mediated responses and the reduced content of PI might be responsible for iPCC1 plants displaying a complex pattern of defence against pathogens of different lifestyles. iPCC1 plants were more susceptible to the hemi-biotrophic oomycete pathogen Phytophthora brassicae and more resistant to the necrotrophic fungal pathogen Botrytis cinerea compared with wild-type plants.
Related JoVE Video
Prenatal Prediction of Surgical Approach for Coarctation of the Aorta Repair.
Fetal. Diagn. Ther.
PUBLISHED: 06-09-2013
Show Abstract
Hide Abstract
Objective: To evaluate the capacity of fetal echocardiography for predicting the more likely surgical approach in newborns with coarctation of the aorta (CoAo) (left thoracotomy vs. median sternotomy). Material and Methods: We selected all cases of suspected CoAo prenatally diagnosed in 2003-2012 (n = 95). 49/95 were considered at high-risk and 46/95 at low-risk of CoAo, and 38/49 and 7/46 were postnatally confirmed, respectively. We firstly evaluated in 40 cases of CoAo surgically repaired (24 thoracotomy, 16 sternotomy) whether there were differences in fetal echocardiographic parameters between both groups. Secondly, we assessed the performance of these parameters for predicting the surgical approach in fetuses at high risk of CoAo. Results: Sternotomy approach was associated with higher rate of postoperative complications and longer hospital stay compared with thoracotomy (81.3 vs. 41.7%, p = 0.014; 30.5 vs. 15.4 days, p = 0.0004, respectively). The Z-score of the aortic isthmus, measured in the sagittal plane, was significantly smaller in the sternotomy group. In fetuses at high-risk of having CoAo a cut-off value of the isthmus Z-score ? -2.5 had sensitivity of 78% and specificity of 82% for predicting sternotomy approach, with 9% false positive cases in which CoAo was not confirmed. Discussion: The surgical approach for CoAo repair may be prenatally predicted by means of the Z-score of aortic isthmus, measured in the sagittal plane. © 2013 S. Karger AG, Basel.
Related JoVE Video
Prevalence of gastrointestinal nematodes and Fasciola hepatica in sheep in the northwest of Spain: relation to climatic conditions and/or man-made environmental modifications.
Parasit Vectors
PUBLISHED: 03-16-2013
Show Abstract
Hide Abstract
In the present study we studied and updated the prevalence of the infections caused by gastrointestinal nematodes (GIN) and Fasciola hepatica in grazing sheep in the northwest (NW) of Spain for the last six years (2006-2011), and its relationship with the current climatic conditions.
Related JoVE Video
Plasma renin-angiotensin system-regulating aminopeptidase activities are modified in early stage Alzheimers disease and show gender differences but are not related to apolipoprotein E genotype.
Exp. Gerontol.
PUBLISHED: 03-05-2013
Show Abstract
Hide Abstract
Alterations in blood pressure and components of the renin-angiotensin system (RAS) contribute to the development and progression of Alzheimers disease (AD), resulting in changes that can lead or contribute to cognitive decline. Aspartyl aminopeptidase (ASAP), aminopeptidase A (APA), aminopeptidase N (APN) and aminopeptidase B (APB) catabolise circulating angiotensins, whereas insulin-regulated aminopeptidase (IRAP) has been described as the AT4 receptor. We have found in AD patients a significant decrease of APA activity in men but not in women, and of APN, APB and IRAP in both genders, when compared with control subjects. No changes were found in ASAP activity. Also, APN, APB and IRAP but not APA correlated with the Mini-Mental test, but no relationship with APOE genotype was found. We conclude that several components of the RAS are modified in AD patients, with gender differences. Furthermore, ROC analysis indicates that APN, APB and IRAP activities could be useful non-invasive biomarkers of AD from the earliest stages.
Related JoVE Video
Determination of alcohols in essential oils by liquid chromatography with ultraviolet detection after chromogenic derivatization.
J Chromatogr A
PUBLISHED: 02-26-2013
Show Abstract
Hide Abstract
An HPLC-UV method to determine compounds having a hydroxyl functional group in plant essential oils is developed. The sample is diluted with 1,4-dioxane and the analytes are derivatized with phthalic anhydride. The derivatives (phthalates hemiesters) are separated on a C8 column using an acetonitrile (ACN)/water gradient. Separation conditions were optimized using the DryLab(®) method development software. For the alcohols and phenols present in mint and rose essential oils, optimization led to a ca. 40min gradient time and a column temperature of 8°C. The alcohol and its derivatives were identified using HPLC with mass spectrometry (MS) detection. A large sensitivity enhancement was obtained by derivatization protocol. The HPLC-UV method was compared to GC with flame ionization detector (FID) and GC-MS. The limits of detection (LODs) obtained by the proposed method were better than those obtained by GC-FID and of the same order as those achieved by GC-MS. The three methods were satisfactorily applied to the determination of alcohols in essential oils. Therefore, the recommended method is of interest as an alternative to GC methods, to investigate the presence of compounds having an alcohol group at low concentrations in essential oils.
Related JoVE Video
Methacrylate monolithic columns functionalized with epinephrine for capillary electrochromatography applications.
J Chromatogr A
PUBLISHED: 01-17-2013
Show Abstract
Hide Abstract
Epinephrine-bonded polymeric monoliths for capillary electrochromatography (CEC) were developed by nucleophilic substitution reaction of epoxide groups of poly(glycidyl-methacrylate-co-ethylenedimethacrylate) (poly(GMA-co-EDMA)) monoliths using epinephrine as nucleophilic reagent. The ring opening reaction under dynamic conditions was optimized. Successful chemical modification of the monolith surface was ascertained by in situ Raman spectroscopy characterization. In addition, the amount of epinephrine groups that was bound to the monolith surface was evaluated by oxidation of the catechol groups with Ce(IV), followed by spectrophotometric measurement of unreacted Ce(IV). About 9% of all theoretical epoxide groups of the parent monolith were bonded to epinephrine. The chromatographic behavior of the epinephrine-bonded monolith in CEC conditions was assessed with test mixtures of alkyl benzenes, aniline derivatives and substituted phenols. In comparison to the poly(GMA-co-EDMA) monoliths, the epinephrine-bonded monoliths exhibited a much higher retention and slight differences in selectivity. The epinephrine-bonded monolith was further modified by oxidation with a Ce(IV) solution and compared with the epinephrine-bonded monoliths. The resulting monolithic stationary phases were evaluated in terms of reproducibility, giving RSD values below 9% in the parameters investigated.
Related JoVE Video
De novo assembly and functional annotation of the olive (Olea europaea) transcriptome.
DNA Res.
PUBLISHED: 01-07-2013
Show Abstract
Hide Abstract
Olive breeding programmes are focused on selecting for traits as short juvenile period, plant architecture suited for mechanical harvest, or oil characteristics, including fatty acid composition, phenolic, and volatile compounds to suit new markets. Understanding the molecular basis of these characteristics and improving the efficiency of such breeding programmes require the development of genomic information and tools. However, despite its economic relevance, genomic information on olive or closely related species is still scarce. We have applied Sanger and 454 pyrosequencing technologies to generate close to 2 million reads from 12 cDNA libraries obtained from the Picual, Arbequina, and Lechin de Sevilla cultivars and seedlings from a segregating progeny of a Picual × Arbequina cross. The libraries include fruit mesocarp and seeds at three relevant developmental stages, young stems and leaves, active juvenile and adult buds as well as dormant buds, and juvenile and adult roots. The reads were assembled by library or tissue and then assembled together into 81 020 unigenes with an average size of 496 bases. Here, we report their assembly and their functional annotation.
Related JoVE Video
Group IIC intron with an unusual target of integration in Enterobacter cloacae.
J. Bacteriol.
PUBLISHED: 10-21-2011
Show Abstract
Hide Abstract
A potential role of group IIC-attC introns in integron gene cassette formation, that is, the way in which they could provide the attC sequence essential for recombination, has been proposed. Group IIC introns usually target the attC site of gene cassettes and more specifically their inverse core. Here we characterized a novel group IIC intron targeting the core site of the aadA1 gene cassette attC site (aadA1-qacE?1 gene cassette junction) from enterobacterial isolates. Intron mobility (retrohoming) was analyzed using a two-plasmid assay performed in Escherichia coli. Intron mobility assays confirmed the mobilization-integration of the group II intron into the core site of the aadA2, bla(VIM-2), bla(CARB-2), aac(6)-Ib, dfrXVb, arr2, cmlA4, and aadB gene cassettes but not into the attI site. This mobility was dependent on maturase activity. Reverse transcriptase PCR showed that this intron was transcriptionally active, and an intermediate circular form was detected by inverse PCR. This element was linked to the bla(VEB-1) extended-spectrum ?-lactamase gene in a high number of enterobacterial isolates. A phylogenetic tree showed that the identified element was located in a branch separate from group IIC-attC introns, being an IIC intron possessing the ability to integrate using the core site of the attC sites as target.
Related JoVE Video
Capillary electrophoresis of free fatty acids by indirect ultraviolet detection: application to the classification of vegetable oils according to their botanical origin.
J. Agric. Food Chem.
PUBLISHED: 09-22-2011
Show Abstract
Hide Abstract
A method for the determination of fatty acids in vegetable oils by capillary electrophoresis with indirect UV-vis detection has been developed. The separation of fatty acids was optimized in terms of Brij surfactant nature and concentration and organic modifier (2-propanol) percentage. The optimal background electrolyte consisted of 10 mM p-hydroxybenzoate, 5 mM Tris at pH 8.8, 80 mM Brij 98, 40% acetonitrile, and 10% 2-propanol. Under these conditions, vegetable oils from five botanical origins (avocado, corn, extra virgin olive, hazelnut, and soybean) were analyzed and the fatty acid contents established. Linear discriminant analysis (LDA) models were constructed using fatty acid peak areas as predictors. An excellent resolution among all category pairs was obtained, and all samples were correctly classified with assignment probabilities of >95%.
Related JoVE Video
Evaluation of three automated systems for susceptibility testing of enterobacteria containing qnrB, qnrS, and/or aac(6)-Ib-cr.
J. Clin. Microbiol.
PUBLISHED: 07-20-2011
Show Abstract
Hide Abstract
The accuracy of the MicroScan WalkAway, BD Phoenix, and Vitek-2 systems for susceptibility testing of quinolones and aminoglycosides against 68 enterobacteria containing qnrB, qnrS, and/or aac(6 )-Ib-cr was evaluated using reference microdilution. Overall, one very major error (0.09%), 6 major errors (0.52%), and 45 minor errors (3.89%) were noted.
Related JoVE Video
Alpha-1-adrenergic receptor blockade modifies insulin-regulated aminopeptidase (IRAP) activity in rat prostate and modulates oxytocin functions.
Drug Metab Lett
PUBLISHED: 06-15-2011
Show Abstract
Hide Abstract
Oxytocin (OT) is one of the important paracrine factors that prostate synthesizes. OT maintains its resting tone and stimulates its contractile activity. However, the involvement of OT in modulating cell proliferation of the prostate is being investigated. In fact, alterations in OT concentrations accompany both benign prostatic hyperplasia/hypertrophy and carcinoma of the prostate. The enzyme Insulin-regulated aminopeptidase (IRAP) is the main responsible of OT levels regulation through its catabolism. To date, the long-acting selective ?(1)-adrenergic receptor antagonist doxazosin is widely used to the treatment of BPH. Thus, our aim was to analyze the effects of doxazosin on IRAP specific activity and its putative effects on prostate OT regulation and functions.
Related JoVE Video
Renin angiotensin system-regulating aminopeptidase activities in serum of pre- and postmenopausal women with breast cancer.
Breast
PUBLISHED: 03-28-2011
Show Abstract
Hide Abstract
Angiotensin peptides regulate vascular tone and natriohydric balance through the renin angiotensin system (RAS) and are related with the angiogenesis which plays an important role in the metastatic pathway. Estrogen influences the aminopeptidases (APs) involved in the metabolism of bioactive peptides of RAS through several pathways. We analyze RAS-regulating AP activities in serum of pre- and postmenopausal women with breast cancer to evaluate the putative value of these activities as biological markers of the development of breast cancer. We observed an increase in aminopeptidase N (APN) and aminopeptidase B (APB) activities in women with breast cancer; however, a decrease in aspartyl-aminopeptidase (AspAP) activity in premenopausal women. These results suggest a slow metabolism of angiotensin II (Ang II) to angiotensin III (Ang III) in premenopausal women and a rapid metabolism of Ang III to angiotensin IV (Ang IV) in pre- and postmenopausal women with breast cancer. An imbalance in the signals activated by Ang II may produce abnormal vascular growth with different response between pre- and postmenopausal women depending on the hormonal profile and the development of the disease.
Related JoVE Video
Classification of pumpkin seed oils according to their species and genetic variety by attenuated total reflection Fourier-transform infrared spectroscopy.
J. Agric. Food Chem.
PUBLISHED: 03-16-2011
Show Abstract
Hide Abstract
Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), followed by multivariate treatment of the spectral data, was used to classify seed oils of the genus Cucurbita (pumpkins) according to their species as C. maxima, C. pepo, and C. moschata. Also, C. moschata seed oils were classified according to their genetic variety as RG, Inivit C-88, and Inivit C-2000. Up to 23 wavelength regions were selected on the spectra, each region corresponding to a peak or shoulder. The normalized absorbance peak areas within these regions were used as predictors. Using linear discriminant analysis (LDA), an excellent resolution among all categories concerning both Cucurbita species and C. moschata varieties was achieved. The proposed method was straightforward and quick and can be easily implemented. Quality control of pumpkin seed oils is important because Cucurbita species and genetic variety are both related to the pharmaceutical properties of the oils.
Related JoVE Video
[Theory of planned behavior and risky sexual behavior in homosexual men].
Rev. Panam. Salud Publica
PUBLISHED: 03-09-2011
Show Abstract
Hide Abstract
Explore the appropriateness of the theory of planned behavior (TPB) model for analyzing risky sexual behavior in men who have sex with other men (MSM), with the object of proposing an alternative model that improves understanding.
Related JoVE Video
[Primary care consultations: are they all by the doctor?].
Aten Primaria
PUBLISHED: 03-05-2011
Show Abstract
Hide Abstract
To find out the proportion of primary healthcare consultations that could be attended by another professional other than the doctor.
Related JoVE Video
Evaluation of molecular mass and tacticity of polyvinyl alcohol by non-equilibrium capillary electrophoresis of equilibrium mixtures of a polymer and a dye.
J Chromatogr A
PUBLISHED: 02-14-2011
Show Abstract
Hide Abstract
Non-equilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) has been used to characterize polyvinyl alcohol (PVA). Commercial PVA samples with different molecular masses, from M(w)=15 up to 205 kDa, were used. According to the (13)C NMR spectra, the samples also differed in tacticity (stereoregularity). Mixtures of PVA and the anionic azo-dye Congo Red (CR) were injected in the presence of a borate buffer. The electropherograms gave a band and a peak due to the residual PVA-CR complex and the excess dye, respectively, plus a superimposed exponential decay due to the partial dissociation of the complex during migration. The stoichiometry of the PVA-CR complex, q=[monomer]/[dye], reached a maximum, q(sat), which depended on both M(w) and tacticity of PVA. Thus, q(sat) decreased from a molar ratio of ca. 4.9 to 3.6 at increasing M(w) values, this variation also being largely dependent on tacticity. A similar dependence of the electrophoretic mobility of the complex on both M(w) and tacticity was also observed. A possible explanation, based on the formation of a stack of CR ions inside the PVA-CR complex, was proposed and discussed. Finally, at increasing M(w) values, the stability constant of the complex increased slightly, and the pseudo-first order dissociation rate of the complex decreased, this later parameter also showing a dependence on both M(w) and tacticity.
Related JoVE Video
Students Factors Affecting Undergraduates Perceptions of their Teaching and Learning Process within ECTS Experience.
Front Psychol
PUBLISHED: 02-10-2011
Show Abstract
Hide Abstract
Introduction: In the present study, we investigated the potential factors that influenced the level of students satisfaction with the teaching-learning process (TLP), from the perspective of students participating in the European Credit Transfer System (ECTS) experience. Method: A total of 1490 students from the Universities of Almería and Granada (Spain) participated in an evaluation of their class discipline area. They completed the new revised protocol for evaluating the ECTS experience. Analyses of variance were carried out, taking the following factors as independent variables: students grade average, year in school, study discipline, credit load in terms of ECTS credits assigned to a subject, the e-learning approach. Perception of the TLP was used as the dependent variable. Results: The data analyses showed variability of the degree of statistically significance among the factors that influenced students perceptions of the TLP. These factors included: Students grade average (in favor of high performers), year in school (in favor of earlier years), ECTS load (in favor of subjects with a medium load of credits), and e-learning (in favor of its use). These research findings provided evidence to explore the delineation of a potential profile of factors that trigger a favorable perception of the TLP. Discussion and Conclusion: The present findings certainly have implications to deepen our understanding of the core beliefs, commitment, and the experience in shaping the implementation of the European Higher Education Area through the ECTS.
Related JoVE Video
Sensitive determination of polycyclic aromatic hydrocarbons in water samples using monolithic capillary solid-phase extraction and on-line thermal desorption prior to gas chromatography-mass spectrometry.
J Chromatogr A
PUBLISHED: 02-05-2011
Show Abstract
Hide Abstract
A methacrylate-based monolithic capillary column has been evaluated for the preconcentration of polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. For this purpose, the monolyte was in situ synthesized in a 6cm×0.32mm id fused-silica capillary. The microextraction unit was fitted to a micro-HPLC pump to pass 10mL of sample. The isolated pollutants were eluted by means of 10?L of methanol, the organic phase being directly collected in a specific interface that can be fitted to the injection port of the gas chromatograph without modification. The interface allows the on-line thermal desorption of the PAHs, avoiding the dilution and providing enough sensitivity to reach the legal limits established for these pollutants in the matrices selected. The limits of detection achieved for 10mL of water ranged between 2.8ng/L (indeno(1,2,3-cd)pyrene) and 11.5ng/L (acenaphthene) with acceptable precision (between 4.5 and 18.2% RSD). The method was applied to the determination of the selected PAHs in tap, river waters and sewage, being fluoranthene and pyrene detected in all of them at concentrations lower than the legal limits established for these compounds in the matrices assayed.
Related JoVE Video
Hypothalamus-pituitary-thyroid axis disruption in rats with breast cancer is related to an altered endogenous oxytocin/insulin-regulated aminopeptidase (IRAP) system.
Tumour Biol.
PUBLISHED: 01-05-2011
Show Abstract
Hide Abstract
Associations of breast cancer with diseases of the thyroid have been repeatedly reported, but the mechanism underlying this association remains to be elucidated. It has been reported that oxytocin (OXT) attenuates the thyroid-stimulating hormone (TSH) release in response to thyrotrophin-releasing hormone (TRH) and decreased plasma levels of TSH as well as the thyroid hormones by an effect mediated by the central nervous system. Oxytocinase (IRAP) is the regulatory proteolytic enzyme reported to hydrolyze OXT. Changes in IRAP activity have been reported in both human breast cancer and N-methyl-nitrosourea (NMU)-induced rat mammary tumours. Here, we measure IRAP activity fluorometrically using cystyl-?-naphthylamide as the substrate, in the hypothalamus-pituitary-thyroid axis together with the circulating levels of OXT, and its relationship with circulating levels of TSH and free thyroxine (fT4), as markers of thyroid function in control rats and rats with breast cancer induced by NMU. We found decreased thyroid function in rats with breast cancer induced by NMU, supported by the existence of lower serum circulating levels of both TSH and fT4 than their corresponding controls. Concomitantly, we found a decrease of hypothalamic IRAP activity and an increase in circulating levels of OXT. We propose that breast cancer increases OXT pituitary release by decreasing its hypothalamic catabolism through IRAP activity, probably due to the alteration of the estrogenic endocrine status. Thus, high circulating levels of OXT decreased TSH release from the pituitary, and therefore, of thyroid hormones from the thyroid, supporting the association between breast cancer and thyroid function disruption.
Related JoVE Video
[Perception of the teaching-learning process and academic achievement in diverse instructional contexts of Higher Education].
Psicothema
PUBLISHED: 11-04-2010
Show Abstract
Hide Abstract
In Higher Education, performance and Teaching-Learning (T-L) contexts are highly current concerns. Based on the DEDEPRO model, interdependence can be established between instructional contexts and levels of performance as they relate to the T-L process. Partitipants were 2020 pupils from two Spanish universities. Measurements of both variables were used in a quasi-experimental and correlational design. The univariate and causal analyses showed the effect of context on the T-L process and on performance; thus, the interdependent relationships between the latter and perception of the T-L process. Partial interaction effects also appeared, as well as a causal model of academic performance. Results are discussed and implications for the ECTS (European Credit Transfer System) are analyzed.
Related JoVE Video
Genetic and functional variability of AmpC-type ?-lactamases from Acinetobacter baumannii.
Antimicrob. Agents Chemother.
PUBLISHED: 08-16-2010
Show Abstract
Hide Abstract
The incidence of naturally occurring AmpC ?-lactamases with extended activities toward several cephalosporins was evaluated among 17 ceftazidime (CAZ)-resistant Acinetobacter baumannii isolates. Five AmpC ?-lactamases (named ADC ?-lactamases) were identified, among which those possessing the Val208Ala (inside the omega-loop) or Asn283Ser (helix H-10) substitution conferred higher levels of resistance (4- to 64-fold higher) to CAZ and to cefotaxime in Escherichia coli. This study demonstrates that peculiar AmpCs playing a role in resistance to broad-spectrum cephalosporins in A. baumannii may be identified.
Related JoVE Video
An ab initio molecular dynamics study on the hydrolysis of the Po(IV) aquaion in water.
J Phys Chem B
PUBLISHED: 08-11-2010
Show Abstract
Hide Abstract
Po(IV) in water has been studied by means of Car-Parrinello molecular dynamics (CPMD) simulations. A new Trouiller-Martins pseudopotential for Po(IV) has been developed. This pseudopotential was tested by comparing the structure and energetics of small [Po(H(2)O)(n)(OH)(m)](4-m) clusters optimized quantum-mechanically. CP-MD simulations of 1 Po + 60 H(2)O were carried out starting from three different degrees of hydrolysis of the aquaion (m = 0, 2, and 3), in order to check the stability of the hydrolyzed forms under the simulation conditions. The three simulations converge to a description of the solution where the same hydrolyzed species are present. Dynamics of the octahydrate aquaion in water indicates that dehydration couples to hydrolysis processes, and the total coordination number decreases with the hydrolysis degree. The time evolution of the initial [Po(H(2)O)(8)](4+) aquaion in aqueous solution indicates that hydrolysis precedes to dehydration in the process from aquaion to hydroxoaquaion. Structural and dynamical properties of the ligands in the first coordination shell are analyzed. The power spectra and its contribution from fragments of the first coordination shell are also examined.
Related JoVE Video
Methacrylate ester-based monolithic columns for nano-LC separation of tocopherols in vegetable oils.
J Sep Sci
PUBLISHED: 07-21-2010
Show Abstract
Hide Abstract
The separation and determination of tocopherols (Ts) in vegetable oils by nano-LC chromatography with UV-vis detection using lauryl methacrylate ester-based monolithic columns has been developed. The separation of Ts was optimized in terms of mobile phase composition on the basis of the best compromise among efficiency, resolution and analysis time. Using a mobile phase composed of ACN/methanol/water, an excellent resolution between Ts was achieved within 18 min. The LODs were lower than 0.26 ?g/mL, being repeatability values of retention time and peak area below 0.15 and 3.1%, respectively. The method was applied to the quantification of Ts and tocotrienols present in several vegetable oils from different botanical origins.
Related JoVE Video
Plasmid-mediated quinolone resistance: an update.
J. Infect. Chemother.
PUBLISHED: 06-29-2010
Show Abstract
Hide Abstract
In 1998, the first plasmid-mediated gene involved in quinolone resistance (currently named qnrA1) was reported. Extra qnr-like plasmid-mediated genes (qnrB, qnrS, qnrC, qnrD) and their chromosomal homologues have also been characterized. These genes code for a pentapeptide repeat protein that protects type II topoisomerases from quinolones. Since then, there have been reports of two other plasmid-mediated resistance mechanisms: the modification of quinolones with a piperazinyl substituent by the acetyltransferase, Aac(6)-Ib-cr; and active efflux by QepA and OqxAB, pumps related to major facilitator superfamily (MFS) transporters. These genes have a wide geographic distribution (mainly in Enterobacteriaceae). Because of the difficulties of phenotypic detection of this type of resistance, its real prevalence is only partially known. One important point is that although these mechanisms cause only low-level resistance, they favor and complement the selection of other resistance mechanisms.
Related JoVE Video
Extended-spectrum cephalosporinase in Acinetobacter baumannii.
Antimicrob. Agents Chemother.
PUBLISHED: 06-14-2010
Show Abstract
Hide Abstract
An AmpC-type beta-lactamase conferring high-level resistance to expanded-spectrum cephalosporins and monobactams was characterized from an Acinetobacter baumannii clinical isolate. This class C beta-lactamase (named ADC-33) possessed a Pro210Arg substitution together with a duplication of an Ala residue at position 215 (inside the Omega-loop) compared to a reference AmpC cephalosporinase from A. baumannii. ADC-33 hydrolyzed ceftazidime, cefepime, and aztreonam at high levels, which allows the classification of this enzyme as an extended-spectrum AmpC (ESAC). Site-directed mutagenesis confirmed the role of both substitutions in its ESAC property.
Related JoVE Video
Is distortion of the bioprosthesis ring a risk factor for early calcification?
J Cardiothorac Surg
PUBLISHED: 04-13-2010
Show Abstract
Hide Abstract
As the population ages, bioprosthesis are increasingly being used in cardiac valve replacement. Pericardial bioprosthesis combine an excellent hemodynamic performance with low thrombogenicity, but valve failure associated with calcification remains a concern with these valves. We describe distortion of the bioprosthesis ring as a risk factor for early calcification.
Related JoVE Video
Mammary renin-angiotensin system-regulating aminopeptidase activities are modified in rats with breast cancer.
Tumour Biol.
PUBLISHED: 04-12-2010
Show Abstract
Hide Abstract
Angiotensin II in particular and/or the local renin-angiotensin system in general could have an important role in epithelial tissue growth and modelling; therefore, it is possible that it may be involved in breast cancer. In this sense, previous works of our group showed a predominating role of angiotensin II in tumoral tissue obtained from women with breast cancer. However, although classically angiotensin II has been considered the main effector peptide of the renin-angiotensin system cascade, several of its catabolism products such as angiotensin III and angiotensin IV also possess biological functions. These peptides are formed through the activity of several proteolytic regulatory enzymes of the aminopeptidase type, also called angiotensinases. The aim of this work was to analyse several specific angiotensinase activities involved in the renin-angiotensin system cascade in mammary tissue from control rats and from rats with mammary tumours induced by N-methyl-nitrosourea (NMU), which may reflect the functional status of their target peptides under the specific conditions brought about by the tumoural process. The results show that soluble and membrane-bound specific aspartyl aminopeptidase activities and membrane-bound glutamyl aminopeptidase activity increased in mammary tissue from NMU-treated animals and soluble aminopeptidase N and aminopeptidase B activities significantly decreased in mammary tissue from NMU-treated rats. These changes support the existence of a local mammary renin-angiotensin system and that this system and its putative functions in breast tissue could be altered by the tumour process, in which we suggest a predominant role of angiotensin III. All described data about the renin-angiotensin system in mammary tissue support the idea that it must be involved in normal breast tissue functions, and its disruption could be involved in one or more steps of the carcinogenesis process.
Related JoVE Video
Increasing omega-3 desaturase expression in tomato results in altered aroma profile and enhanced resistance to cold stress.
Plant Physiol.
PUBLISHED: 04-09-2010
Show Abstract
Hide Abstract
One of the drawbacks in improving the aroma properties of tomato (Solanum lycopersicum) fruit is the complexity of this organoleptic trait, with a great variety of volatiles contributing to determine specific quality features. It is well established that the oxylipins hexanal and (Z)-hex-3-enal, synthesized through the lipoxygenase pathway, are among the most important aroma compounds and impart in a correct proportion some of the unique fresh notes in tomato. Here, we confirm that all enzymes responsible for the synthesis of these C6 compounds are present and active in tomato fruit. Moreover, due to the low odor threshold of (Z)-hex-3-enal, small changes in the concentration of this compound could modify the properties of the tomato fruit aroma. To address this possibility, we have overexpressed the omega-3 fatty acid desaturases FAD3 and FAD7 that catalyze the conversion of linoleic acid (18:2) to linolenic acid (18:3), the precursor of hexenals and its derived alcohols. Transgenic OE-FAD tomato plants exhibit altered fatty acid composition, with an increase in the 18:3/18:2 ratio in leaves and fruits. These changes provoke a clear variation in the C6 content that results in a significant alteration of the (Z)-hex-3-enal/hexanal ratio that is particularly important in ripe OE-FAD3FAD7 fruits. In addition to this effect on tomato volatile profile, OE-FAD tomato plants are more tolerant to chilling. However, the different behaviors of OE-FAD plants underscore the existence of separate fatty acid fluxes to ensure plant survival under adverse conditions.
Related JoVE Video
Study of elution behaviour with gradient voltage in CEC using methacrylate monolithic columns.
Electrophoresis
PUBLISHED: 03-24-2010
Show Abstract
Hide Abstract
A theoretical study on the retention behaviour and chromatographic performance of neutral solutes using a lauryl methacrylate-based monolithic column under voltage gradient mode in CEC was carried out. Through a flexible mathematical function based on a modified Gaussian model, the peak shape of compounds was firstly fitted under constant and gradient voltage. Using the peak shape parameters and retention time, the estimation of global chromatographic performance, efficiency and peak capacity under several voltage conditions was performed. The influence of voltage gradient on the separation efficiency is discussed and simple equations are presented to calculate retention and peak widths under voltage gradient conditions. A comparison in terms of chromatographic performance of a test mixture of neutral solutes under constant and gradient voltage modes was also carried out. The experiments carried out under gradient voltage showed better efficiencies (172,000 plates/m) and lower peak widths than those obtained under constant voltage (52,000 plates/m).
Related JoVE Video
Characterization of DIM-1, an integron-encoded metallo-beta-lactamase from a Pseudomonas stutzeri clinical isolate in the Netherlands.
Antimicrob. Agents Chemother.
PUBLISHED: 03-22-2010
Show Abstract
Hide Abstract
A carbapenem-resistant Pseudomonas stutzeri strain isolated from a Dutch patient was analyzed in detail. This isolate produced a metallo-beta-lactamase (MBL) whose gene, with 43.5% GC content, was cloned and expressed in Escherichia coli. beta-Lactamase DIM-1 (for Dutch imipenemase) was weakly related to other Ambler class B beta-lactamases, sharing <52% amino acid identity with the most closely related MBL, GIM-1, and 45% identity with IMP-type MBLs. The beta-Lactamase DIM-1 significantly hydrolyzed broad-spectrum cephalosporins and carbapenems and spared aztreonam. This MBL gene was embedded in a class 1 integron containing two other gene cassettes, encoding resistance to aminoglycosides and disinfectants, that was located on a 70-kb plasmid.
Related JoVE Video
Fast separation and determination of sterols in vegetable oils by ultraperformance liquid chromatography with atmospheric pressure chemical ionization mass spectrometry detection.
J. Agric. Food Chem.
PUBLISHED: 02-12-2010
Show Abstract
Hide Abstract
A method for the determination of sterols in vegetable oils by ultraperformance liquid chromatography (UPLC) with atmospheric pressure chemical ionization mass spectrometry detection has been developed. The separation of sterols was optimized in terms of mobile phase composition, column temperature and flow rate. The optimal conditions were achieved using an Acquity UPLC BEH C18 column (50 x 2.1 mm, 1.7 microm) with a mobile phase consistent of acetonitrile/water (0.01% acetic acid) using a linear gradient, at a flow rate of 0.8 mL min(-1) and column temperature of 10 degrees C, giving a total analysis time below 5 min. The determination was performed in selective ion recording mode. The limits of detection were in all cases below 0.07 microg mL(-1), with relative standard deviation values of retention times and peak areas below 0.4 and 5%, respectively. The content of main sterols present in several vegetable oils with different botanical origins was also established.
Related JoVE Video
Ovarian renin--angiotensin system-regulating aminopeptidases are involved in progesterone overproduction in rats with mammary tumours induced by N-methyl nitrosourea.
Anticancer Res.
PUBLISHED: 12-25-2009
Show Abstract
Hide Abstract
A local renin-angiotensin system (RAS) has been found in ovary. This ovarian RAS may regulate ovarian steroidogenesis. Ample studies show that the ovarian hormones estradiol (E2) and progesterone (P) are strongly implicated in the development of breast cancer.
Related JoVE Video
VIM-19, a metallo-beta-lactamase with increased carbapenemase activity from Escherichia coli and Klebsiella pneumoniae.
Antimicrob. Agents Chemother.
PUBLISHED: 11-16-2009
Show Abstract
Hide Abstract
Two carbapenem-resistant isolates, one Escherichia coli isolate and one Klebsiella pneumoniae isolate, recovered from an Algerian patient expressed a novel VIM-type metallo-beta-lactamase (MBL). The identified bla(VIM-19) gene was located on a ca. 160-kb plasmid and located inside a class 1 integron in both isolates. VIM-19 differed from VIM-1 by the Asn215Lys and Ser228Arg substitutions, increasing its hydrolytic activity toward carbapenems. Site-directed mutagenesis experiments showed that both substitutions were necessary for the increased carbapenemase activity of VIM-19. This study indicates that MBLs with enhanced activity toward carbapenems may be obtained as a result of very few amino acid substitutions.
Related JoVE Video
Classification of extra virgin olive oils produced at La Comunitat Valenciana according to their genetic variety using sterol profiles established by high-performance liquid chromatography with mass spectrometry detection.
J. Agric. Food Chem.
PUBLISHED: 11-04-2009
Show Abstract
Hide Abstract
A method to classify extra virgin olive oils (EVOOs) according to their genetic variety using sterol profiles obtained by high-performance liquid chromatography (HPLC) with mass spectrometry (MS) detection has been developed. Sterol extracts were chromatographed on a dC18 Atlantis column (100x3 mm, 3 microm) with a gradient of acetonitrile/water (0.01% acetic acid) at a flow rate of 1.0 mL min(-1) and positive-ion mode MS detection. Using linear discriminant analysis of the HPLC-MS data (extracted ion chromatograms), EVOO samples belonging to six genetic varieties cultivated at La Comunitat Valenciana, Spain (Arbequina, Borriolenca, Canetera, Farga, Picual, and Serrana), were correctly classified with an excellent resolution among all of the categories.
Related JoVE Video
Photo-polymerized lauryl methacrylate monolithic columns for CEC using lauroyl peroxide as initiator.
Electrophoresis
PUBLISHED: 10-10-2009
Show Abstract
Hide Abstract
Lauryl methacrylate (LMA)-ester based monolithic columns photo-polymerized using lauroyl peroxide (LPO) as initiator were prepared, and their morphological and CEC properties were studied. The composition of the polymerization mixture (i.e. ratios of monomers/porogenic solvents, 1,4-butanediol/1-propanol and LMA/crosslinker) was optimized. The morphological and chromatographic properties of LMA columns were evaluated by means of SEM pictures and van Deemter plots of PAHs, respectively. The polymerization mixture selected as optimal provided a fast separation of a mixture of PAHs with excellent efficiencies (minimum plate heights of 8.9-11.1 microm). Satisfactory column-to-column (RSD<4.5%) and batch-to-batch reproducibilities (RSD<6.3%) were achieved. The LMA columns photo-polymerized with LPO were compared with those prepared with AIBN. Using PAHs, alkylbenzenes and basic compounds for testing, the columns obtained with LPO gave the best compromise between efficiency, resolution and analysis time.
Related JoVE Video
[Violent youth gangs in Madrid: socialization and culturalization].
Rev. Panam. Salud Publica
PUBLISHED: 10-10-2009
Show Abstract
Hide Abstract
This study explores the subject of youth involved in violent groups or gangs, with the goal of further understanding the indoctrination, socialization, and culturalization processes undergone by youth involved in group violence or gangs. Furthermore, to examine the dynamics between peer pressure and other social factors (dating relationships, work, family, etc.) within the theoretical framework of the theories of primary socialization and differential socialization.
Related JoVE Video
Prediction of the genetic variety of extra virgin olive oils produced at La Comunitat Valenciana, Spain, by fourier transform infrared spectroscopy.
J. Agric. Food Chem.
PUBLISHED: 10-10-2009
Show Abstract
Hide Abstract
Fourier transform infrared spectroscopy (FTIR), followed by multivariate treatment of the spectral data, was used to classify extra virgin olive oils (EVOOs) according to their genetic variety. EVOO samples corresponding to seven different genetic varieties (Arbequina, Borriolenca, Canetera, Farga, Hojiblanca, Picual, and Serrana) were analyzed. The wavelength scale of the FTIR spectra of the oils was divided into 20 regions. The normalized absorbance peak areas within these regions were used as predictor variables. Classification of the EVOO samples according to their genetic variety was achieved by linear discriminant analysis (LDA). A good resolution among all categories was achieved using a LDA model constructed with only nine predictor variables. With this LDA model, 88% of the EVOOs were correctly classified, with assignment probabilities higher than 95%. This method is helpful for olive oil producers because it provides useful information related to the genetic variety of EVOOs, which is required by European Community regulations.
Related JoVE Video
Up to twenty-five-year survival after aortic valve replacement with size 19 mm valves.
Interact Cardiovasc Thorac Surg
PUBLISHED: 09-21-2009
Show Abstract
Hide Abstract
Long-term survival was investigated in 202 patients who underwent isolated aortic valve replacement (AVR) with 19 mm valves. There were 171 women with a mean age of 69+/-9 years and 31 men with a mean age of 64+/-13 years. Patients had a mean body surface area of 1.61+/-0.13 m(2). Patient-prosthesis mismatch was moderate in 196 and severe in six patients. The mean follow-up for all patients was 78 months. There were 79 late deaths. The actuarial survival rates for all patients were 95+/-1% at 1 year, 75+/-2% at 5 years, 56+/-2% at 10 years, 41+/-2% at 15 years, 34+/-3% at 20 years and 34+/-2% at 25 years. Patients over 70 years old had a lower survival rate (P=0.0001). There were significant differences between ejection fraction (EF) >55% and EF <55% (P=0.0305). AVR with 19 mm valves appeared to provide satisfactory mid-term survival. Age and low EF were risk factors for shorter survival.
Related JoVE Video
Molecular epidemiology and mechanisms of carbapenem resistance in Pseudomonas aeruginosa.
Antimicrob. Agents Chemother.
PUBLISHED: 09-08-2009
Show Abstract
Hide Abstract
The contributions of different mechanisms of resistance to carbapenems among a collection of imipenem- and meropenem-nonsusceptible Pseudomonas aeruginosa isolates were investigated. This screening included the recently reported extended-spectrum cephalosporinases (ESACs) weakly hydrolyzing carbapenems. Eighty-seven percent of the studied isolates were resistant to imipenem. Genes encoding metallo-beta-lactamases or carbapenem-hydrolyzing oxacillinases were not identified. The main mechanism associated with imipenem resistance was the loss of outer membrane protein OprD. Identification of overexpressed ESACs and loss of OprD were observed for 65% of the isolates, all being fully resistant to imipenem. Resistance to meropenem was observed in 78% of the isolates, with all but one also being resistant to imipenem. Overexpression of the MexAB-OprM, MexXY-OprM, or MexCD-OprJ efflux systems was observed in 60% of the isolates, suggesting the contribution of efflux mechanisms in resistance to meropenem. The loss of porin OprD and the overproduction of ESACs were observed in 100% and 92% of the meropenem-resistant isolates, respectively. P. aeruginosa can very often accumulate different resistance mechanisms, including ESAC production, leading to carbapenem resistance.
Related JoVE Video
Deprotonation mechanism of new antihypertensive piperidinylmethylphenols: a combined experimental and theoretical study.
J Phys Chem B
PUBLISHED: 08-06-2009
Show Abstract
Hide Abstract
Four new antihypertensive piperidinylmethylphenol compounds were synthesized for their potential antihypertensive and antiarhythmic properties. The pKa values were determined experimentally, with the aid of the program SQUAD, by capillary zone electrophoresis (CZE) at T=298.15 K and 0.015 M ionic strength (I=0.05 M) and by UV spectrophotometry at pseudophysiological conditions (T=310.15 K and I=0.15 M), obtaining good agreement between the values determined with both techniques. A theoretical study was followed in order to propose a deprotonation mechanism for each compound.
Related JoVE Video
Comparison of thermal- and photo-polymerization of lauryl methacrylate monolithic columns for CEC.
Electrophoresis
PUBLISHED: 06-12-2009
Show Abstract
Hide Abstract
Lauryl methacrylate-based (LMA) monolithic columns for CEC, prepared using either thermal initiation or by UV-irradiation in the presence of AIBN have been compared. Thermal polymerization was carried out at 70 degrees C for 20 h. For UV initiation, the effects of the time exposure to UV light and irradiation energy were investigated. For each initiation process, the influence of composition of porogenic solvent (1,4-butanediol/1-propanol ratio) on the physical and electrochromatographic properties of the resulting monoliths was also evaluated. Photochemically lauryl methacrylate stationary phases initiated showed higher permeabilities and better efficiencies than those prepared by thermal initiation. After optimization of polymerization mixture, photopolymerized columns provided a permeability of 4.25 x 10(-13) m(2) and a minimum plate height of 13.4 microm for a mixture of polycyclic aromatic hydrocarbons. Similar column-to-column and batch-to-batch reproducibilities, with RSD values below 11.6 and 11.0 % for the thermal- and UV-initiated columns, respectively, were obtained.
Related JoVE Video
Naturally occurring Class A ss-lactamases from the Burkholderia cepacia complex.
Antimicrob. Agents Chemother.
PUBLISHED: 05-20-2009
Show Abstract
Hide Abstract
Chromosomally encoded ss-lactamases from the Burkholderia cepacia complex species (formerly Pseudomonas cepacia) were characterized. Cloning and sequencing identified an Ambler class A ss-lactamase (PenB) from B. cenocepacia. It shares 82% amino acid identity with the PenA ss-lactamases previously identified from B. multivorans 249. Its expression was dependent upon a LysR-type regulatory protein. Its narrow-spectrum hydrolysis activity mostly included penicillins but also included expanded-spectrum cephalosporins and aztreonam at lower levels. In that study, Pen-like ss-lactamases (PenC, PenD, PenE, PenF) that shared 63 to 92% identity with PenB from B. cenocepacia were identified from other Burkholderia species. The corresponding ss-lactamase genes might be used as genetic tools for accurate Burkholderia species identification.
Related JoVE Video
Preoperative statin treatment reduces systemic inflammatory response and myocardial damage in cardiac surgery.
Eur J Cardiothorac Surg
PUBLISHED: 04-03-2009
Show Abstract
Hide Abstract
To determine if preoperative statin treatment is associated with a reduction in systemic inflammatory response (SIR) and myocardial damage markers following cardiac surgery with cardiopulmonary bypass (CPB).
Related JoVE Video
Optical gas sensing properties of thermally hydrocarbonized porous silicon Bragg reflectors.
Opt Express
PUBLISHED: 04-01-2009
Show Abstract
Hide Abstract
In the present work, porous silicon (PS) based Bragg reflectors are fabricated, and the reactive PS surface is passivated by means of thermal carbonization (TC) by acetylene decomposition. The gas sensing properties of the reflectors are studied with different gas compositions and concentrations. Based on the results it can be concluded that thermally carbonized Bragg reflectors provide an easy and inexpensive means to produce chemically stable high quality PS reflectors with good gas sensing properties, which differ from those of unpassivated PS reflectors.
Related JoVE Video
Coronary steal by left atrial myxoma: a case report.
Cases J
PUBLISHED: 03-21-2009
Show Abstract
Hide Abstract
This report describes a 41-year-old man who had atypical angina resulting from coronary steal by left atrial myxoma. The tumor was completely excised and the patient was symptoms free after operation.
Related JoVE Video
Extended-spectrum cephalosporinases in Pseudomonas aeruginosa.
Antimicrob. Agents Chemother.
PUBLISHED: 03-02-2009
Show Abstract
Hide Abstract
The characterization of AmpC-type beta-lactamases was performed in a collection of 32 clinical Pseudomonas aeruginosa isolates with intermediate susceptibility or resistance to imipenem and ceftazidime. Twenty-one out of those 32 isolates overexpressed AmpC beta-lactamase, and the MICs of ceftazidime and imipenem were reduced after cloxacillin addition. Cloning and sequencing identified 10 AmpC beta-lactamase variants. Reduced susceptibility to imipenem, ceftazidime, and cefepime was observed only with recombinant P. aeruginosa strains expressing an AmpC beta-lactamase that had an alanine residue at position 105. The catalytic efficiencies (k(cat)/K(m)) of the AmpC variants possessing this residue were increased against oxyiminocephalosporins and imipenem. In addition, we show here that those AmpC variants constitute a favorable background for the in vitro selection of imipenem-resistant strains. This report identified a novel resistance mechanism that may contribute to imipenem resistance in P. aeruginosa.
Related JoVE Video
Study of peak shape and efficiency in butyl acrylate-based monolithic columns for capillary electrochromatography.
J Chromatogr A
PUBLISHED: 01-09-2009
Show Abstract
Hide Abstract
The study and modelling peak shape of in capillary electrochromatography (CEC), obtained using butyl acrylate (BA)-based monolithic columns, is described in this article. A modified-Gaussian model, which is a function of conventional experimental parameters: retention time (t(R)), peak height (H(0)) and standard deviation (sigma(0)) at the peak maximum, and left (A) and right (B) halfwidths, was used to describe the peaks of thiourea and several polyaromatic hydrocarbons compounds, which were eluted under several applied voltages. A mean relative error below 2% in the prediction of peak shape is obtained. Based on peak parameters, an easy and reliable estimation of global chromatographic performance, efficiency and peak capacity of BA-based monoliths was also considered. A comparison in terms of chromatographic performance of BA-based monoliths in CEC with CE mode and RPLC microparticulate columns was also performed.
Related JoVE Video
Chemical composition, antioxidant properties and antimicrobial activity of the essential oil of Murraya paniculata leaves from the mountains of Central Cuba.
Nat Prod Commun
Show Abstract
Hide Abstract
The essential oil of Murraya paniculata L leaves from the mountains of the Central Region of Cuba, obtained by hydrodistillation, was analyzed by gas chromatography-mass spectrometry. Eighteen compounds, accounting for 95.1% of the oil were identified. The major component was beta-caryophyllene (ca. 30%). The antioxidant activity of essential oil was evaluated against Cucurbita seed oil by peroxide, thiobarbituric acid and p-anisidine methods. The essential oil showed stronger antioxidant activity than that of butylated hydroxyanisole and butylated hydroxytoluene, but lower than that of propyl gallate. Moreover, this antioxidant activity was supported by the complementary antioxidant assay in the linoleic acid system and 2, 2-diphenyl-1-picrylhydrazyl. The essential oil also showed good to moderate inhibitory effects against Klebsiellapneumoniae and Bacillus subtilis.
Related JoVE Video
Glucose-induced ?-catenin acetylation enhances Wnt signaling in cancer.
Mol. Cell
Show Abstract
Hide Abstract
Nuclear accumulation of ?-catenin, a widely recognized marker of poor cancer prognosis, drives cancer cell proliferation and senescence bypass and regulates incretins, critical regulators of fat and glucose metabolism. Diabetes, characterized by elevated blood glucose levels, is associated with increased cancer risk, partly because of increased insulin growth factor 1 signaling, but whether elevated glucose directly impacts cancer-associated signal-transduction pathways is unknown. Here, we show that high glucose is essential for nuclear localization of ?-catenin in response to Wnt signaling. Glucose-dependent ?-catenin nuclear retention requires lysine 354 and is mediated by alteration of the balance between p300 and sirtuins that trigger ?-catenin acetylation. Consequently ?-catenin accumulates in the nucleus and activates target promoters under combined glucose and Wnt stimulation, but not with either stimulus alone. Our results reveal a mechanism by which high glucose enhances signaling through the cancer-associated Wnt/?-catenin pathway and may explain the increased frequency of cancer associated with obesity and diabetes.
Related JoVE Video
Quantum-mechanical study on the aquaions and hydrolyzed species of Po(IV), Te(IV), and Bi(III) in water.
J Phys Chem B
Show Abstract
Hide Abstract
A systematic study of [M(H(2)O)(n)(OH)(m)](q+) complexes of Te(IV) and Bi(III) in solution has been undertaken by means of quantum mechanical calculations. The results have been compared with previous information obtained for the same type of Po(IV) complexes ( J. Phys. Chem. B 2009 , 113 , 487 ) to get insight into the similarities and differences among them from a theoretical view. The evolution of the coordination number (n + m) with the degree of hydrolysis (m) for the stable species shows a systematic decrease regardless the ion. A general behavior on the M-O distances when passing from the gas phase to solution, represented by the polarizable continuum model (PCM), is also observed: R(M-O) values corresponding to water molecules decrease, while those of the hydroxyl groups slightly increase. The hydration numbers of aquaions are between 8 and 9 for the three cations, whereas hydrolyzed species behave differently for Te(IV) and Po(IV) than for Bi(III), which shows a stronger trend to dehydrate with the hydrolysis. On the basis of the semicontinuum solvation model, the hydration Gibbs energies are -800 (exptl -834 kcal/mol), -1580 and -1490 kcal/mol for Bi(III), Te(IV), and Po(IV), respectively. Wave function analysis of M-O and O-H bonds along the complexes has been carried out by means of quantum theory of atoms in molecule (QTAIM). Values of electron density and its Laplacian at bond critical points show different behaviors among the cations in aquaions. An interesting conclusion of the QTAIM analysis is that the prospection of the water O-H bond is more sensitive than the M-O bond to the ion interaction. A global comparison of cation properties in solution supplies a picture where the Po(IV) behavior is between those of Te(IV) and Bi(III), but closer to the first one.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.