Synthesis and characterization of DNA-based micro- and nanodumbbell structures

Static barcode labels for individual molecules, based on a sequence of fluorescent segments deterministically encoded in a DNA scaffold, are emerging as sensitive tools for direct digital quantification assays, such as RNA transcript profiling. The next generation of digital barcoding will require dynamic single-molecule labels, which can be controllably translocated, stretched, and read serially by an electronic or optical point detector. Towards that goal, structures consisting of a single magnetic and a single non-magnetic particle connected by a DNA-based linker were synthesized at micron (microdumbbells) and submicron (nanodumbells) scales via successive streptavidin-biotin attachments. Visualization of the structures with fluorescent and atomic force microscopy revealed the desired dumbbell morphology, thus demonstrating the suitability of the synthesis scheme. The stretched DNA-based linker is a convenient template for deterministic, sequence specific information encoding, which indicates the potential of the dumbbell-shaped nanostructures as magnetophoretically driven dynamic barcode labels

Electrochemical miRNA Biosensors: The Benefits of Nanotechnology

The importance of nanotechnology in medical technologies, especially biomedical diagnostics, is indubitable. By taking advantages of nanomaterials, many medical diagnostics methods have been developed so far, including electrochemical nanobiosensors. They have been used for quantification of different clinical biomarkers for detecting, screening, or follow up a disease. microRNAs (miRNAs) are one of the most recent and reliable biomarkers used for biomedical diagnosis of various diseases including different cancer types. In addition, there are many electrochemical nanobiosensors explained in publications, patents, and/or a commercial device which have been fabricated for detection or quantification of valuable miRNAs. The aim of this article is to review the concept of medical diagnostics, biosensors, electrochemical biosensors and to emphasize the role of nanotechnology in nanobiosensor development and performance for application in microRNAs detection for biomedical diagnosis. We have also summarized recent ideas and advancements in the field of electrochemical nanobiosensors for miRNA detection, and the important breakthroughs are also explained

Effect of mixed culture of yeast and microalgae on acetyl-CoA carboxylase and Glycerol-3-phosphate acyltransferase expression

International audienceIn recent years, some studies have reported that co-culturing green algae and yeast improve lipid and biomass concentration. In this study, a co-culture of the oleaginous yeast Rhodotorula glutinis and the microalgae Chlorella vulgaris was consequently conducted with inoculation of microalga and yeast in growth and stationary phases, respectively. For the first time, the expression of two pivotal enzymes in fatty acids synthetic pathway, acetyl-CoA carboxylase and Glycerol-3-phosphate acyltransferase, was evaluated. To evaluate the synergistic impacts of the mixed culture on the enzymes expression, several co-culture models were designed, including the use of different ratio of microalgae to yeast or the use of residual cell-free medium of yeast; a positive impact on enzymes overexpression was shown in the case of the co-culture of the two microorganisms, and when the remaining cell-free medium of yeast was added to the microalgal culture. The results of in vitro co-culture demonstrated increased 6- and 5-fold of nervonic acid (C24:1) and behenic acid (C22:0) concentrations, respectively, in 2:1 microalgae to yeast co-culture as compared to the monoculture batches. Addition of yeast residual cell-free medium in the 2:1 ratio to the microalgal culture enhanced 9 and 6 times nervonic acid (C24:1) and behenic acid (C22:0) amounts, respectively

Effect of nanoparticle treatment on expression of a key gene involved in thymoquinone biosynthetic pathway in <i>Nigella sativa</i> L.

<p>Thymoquinone is the most important secondary metabolite in black Cumin, which has several pharmaceutical applications. In this study, effect of TiO₂ and SiO₂ nanoparticles as new elicitors, on expression of <i>Geranyl diphosphate synthase</i> gene (GPPS gene), as a key gene involved in thymoquione biosynthesis pathway was investigated in two Iranian accessions. Plants were treatment in the early flowering stage and after 24 h of 50 and 100 mg/L of each nanoparticle, separately. After RNA extraction, GPPS gene expression was analysed by qRT-PCR method. The results showed that the TiO₂ and SiO₂ nanoparticles, generally stimulates the GPPS expression. The TiO₂ nanoparticles were more effective than SiO₂ for the induction of GPPS expression. Also, 100 mg/L treatment of nanoparticles raised gene expression more than 50 mg/L concentration. It can be concluded these nanoparticles can be used as robust elicitors to enhance the production of Thymoquinone in black cumin through up-regulation of related metabolic pathway genes.</p

Circulating miR-126 and miR-499 reflect progression of cardiovascular disease; correlations with uric acid and ejection fraction

BackgroundThe aim of this study was to assess plasma levels of endothelium- and heart-associated microRNAs (miRNAs) miR-126 and miR-499, respectively, using quantitative reverse transcriptase polymerase chain reaction.MethodsA two-step analysis was conducted on 75 patients undergoing off-pomp coronary artery bypass graft (CABG) surgery. Five biomarkers of inflammation and cardiac injury were assessed in addition to the above-mentioned miRNAs.ResultsPlasma concentrations of miRNAs were found to be significantly correlated with plasma levels of cardiac troponin I (cTnI) (miR-499, r 0.49, p~0.002; miR-126, r = 0.30, p~0.001), indicating cardiac damage. Data analysis revealed that miR-499 had higher sensitivity and specificity for cardiac injury than miR-126, which reflects more endothelial activation. Interestingly, a strong correlation was observed between both miRNAs and uric acid (UA) levels with ventricular contractility measured as ejection fraction (EF) (miR-499/EF%, r = 0.58, p~0.004; UA/EF%, r = -0.6, p~0.006; UA/miR-499, r = -0.34; UA/miR-126, r = 0.5, p~0.01).ConclusionsIn patients undergoing CABG, circulating miR-126/499 is associated with presentation of traditional risk factors and reflects post-operative response to injury. Plasma pool of miRNAs likely reflects extracellular miRNAs which are proportional to intracellular miRNA levels. Therefore, circulating levels of these miRNAs have prognostic implications in detection of higher risk of future cardiovascular events

A MYB gene from wheat (Triticum aestivum L.) is up-regulated during salt and drought stresses and differentially regulated between salt-tolerant and sensitive genotypes

Crop adaptation to abiotic stresses requires alterations in expression of a large number of stress protection genes and their regulators, including transcription factors. In this study, the expression levels of ten MYB transcription factor genes from wheat (Triticum aestivum) were examined in two recombinant inbred lines contrasting in their salt tolerance in response to salt or drought stress. Quantitative RT-PCR analysis revealed that four MYB genes were consistently up-regulated in the seedling roots of both genotypes under short-term salt treatment. Three MYB genes were found to be up-regulated in both genotypes under long-term salt stress. One MYB gene was up-regulated in both genotypes under both short- and long-term salt stress. Of these salt up-regulated MYB genes, one MYB gene (TaMYBsdu1) was markedly up-regulated in the leaf and root of wheat under long-term drought stress. In addition, TaMYBsdu1 showed higher expression levels in the salt-tolerant genotype than in the susceptible genotype under salt stress. These data suggest that TaMYBsdu1 is a potentially important regulator involved in wheat adaptation to both salt and drought stresses