1,646 research outputs found
Fluorescent turn-on probes for wash-free mRNA imaging via covalent site-specific enzymatic labeling.
Investigating the many roles RNA plays in cellular regulation and function has increased demand for tools to explore RNA tracking and localization within cells. Our recently reported RNA-TAG (transglycosylation at guanine) approach uses an RNA-modifying enzyme, tRNA-guanine transglycosylase (TGT), to accomplish covalent labeling of an RNA of interest with fluorescent tracking agents in a highly selective and efficient manner. Unfortunately, labeling by this method currently suffers from a high nonspecific fluorescent background and is currently unsuitable for imaging RNA within complex cellular environments. Herein we report the design and synthesis of novel fluorogenic thiazole orange probes that significantly lower nonspecific binding and background fluorescence and, as a result, provide up to a 100-fold fluorescence intensity increase after labeling. Using these fluorogenic labeling agents, we were able to image mRNA expressed in Chinese Hamster Ovary cells in a wash-free manner
Spontaneous Ratchet Effect in a Granular Gas
The spontaneous clustering of a vibrofluidized granular gas is employed to
generate directed transport in two different compartmentalized systems: a
"granular fountain" in which the transport takes the form of convection rolls,
and a "granular ratchet" with a spontaneous particle current perpendicular to
the direction of energy input. In both instances, transport is not due to any
system-intrinsic anisotropy, but arises as a spontaneous collective symmetry
breaking effect of many interacting granular particles. The experimental and
numerical results are quantitatively accounted for within a flux model.Comment: 4 pages, 5 figures; Fig. 4 has been reduced in size and qualit
Poincar\'{e} cycle of a multibox Ehrenfest urn model with directed transport
We propose a generalized Ehrenfest urn model of many urns arranged
periodically along a circle. The evolution of the urn model system is governed
by a directed stochastic operation. Method for solving an -ball, -urn
problem of this model is presented. The evolution of the system is studied in
detail. We find that the average number of balls in a certain urn oscillates
several times before it reaches a stationary value. This behavior seems to be a
peculiar feature of this directed urn model. We also calculate the Poincar\'{e}
cycle, i.e., the average time interval required for the system to return to its
initial configuration. The result can be easily understood by counting the
total number of all possible microstates of the system.Comment: 10 pages revtex file with 7 eps figure
Oral serum-derived bovine immunoglobulin improves duodenal immune reconstitution and absorption function in patients with HIV enteropathy.
ObjectivesTo examine the impact of serum-derived bovine immunoglobulin, an oral medical food known to neutralize bacterial antigen and reduce intestinal inflammation, on restoration of mucosal immunity and gastrointestinal function in individuals with HIV enteropathy.DesignOpen-label trial with intensive 8-week phase of bovine serum immunoglobulin (SBI) 2.5 g twice daily with a 4-week washout period and an optional 9-month extension study.MethodsHIV enteropathy was defined as chronic gastrointestinal symptoms including frequent loose or watery stools despite no identifiable, reversible cause. Upper endoscopy for tissue immunofluorescent antibody assay and disaccharide gut permeability/absorption studies were performed before and after 8 weeks of SBI to test mucosal immunity and gastrointestinal function. Blood was collected for markers of microbial translocation, inflammation, and collagen kinetics. A validated gastrointestinal questionnaire assessed changes in symptoms.ResultsAll eight participants experienced profound improvement in symptoms with reduced bowel movements/day (P = 0.008) and improvements in stool consistency (P = 0.008). Gut permeability was normal before and after the intervention, but D-xylose absorption increased in seven of eight participants. Mucosal CD4 lymphocyte densities increased by a median of 139.5 cells/mm2 from 213 to 322 cells/mm2 (P = 0.016). Intestinal-fatty acid binding protein (I-FABP), a marker of enterocyte damage, initially rose in seven of eight participants after 8 weeks (P = 0.039), and then fell below baseline in four of five who continued receiving SBI (P = 0.12). Baseline serum I-FABP levels were negatively correlated with subsequent rise in mucosal CD4 lymphocyte densities (r = -0.74, P = 0.046).ConclusionSBI significantly increases intestinal mucosal CD4 lymphocyte counts, improves duodenal function, and showed evidence of promoting intestinal repair in the setting of HIV enteropathy
Packages of Practices for Sustainable, Ecofriendly Mariculture (Land-based Saline Aquaculture and Seafarming)
The problems of fast growing human population and protein deficit, particularly in the developing countries continue to exert pressure on the fisheries resources available for exploitation in the wild water bodies. The increasingly limited opportunities in the capture fisheries sector have generated considerable interest in aquaculture
HCV IRES manipulates the ribosome to promote the switch from translation initiation to elongation.
The internal ribosome entry site (IRES) of the hepatitis C virus (HCV) drives noncanonical initiation of protein synthesis necessary for viral replication. Functional studies of the HCV IRES have focused on 80S ribosome formation but have not explored its role after the 80S ribosome is poised at the start codon. Here, we report that mutations of an IRES domain that docks in the 40S subunit's decoding groove cause only a local perturbation in IRES structure and result in conformational changes in the IRES-rabbit 40S subunit complex. Functionally, the mutations decrease IRES activity by inhibiting the first ribosomal translocation event, and modeling results suggest that this effect occurs through an interaction with a single ribosomal protein. The ability of the HCV IRES to manipulate the ribosome provides insight into how the ribosome's structure and function can be altered by bound RNAs, including those derived from cellular invaders
A Rapid Micropropagation of nodal explants of Eclipta alba (L.); A Multipurpose Medicinal Herb
An efficient in vitro regeneration protocol was developed for medicinally important plant Eclipta alba. Successful regeneration and multiplication of nodal explants of E. alba were obtained in cytokinin enriched B5 medium. Several cytokinins [6-benzylaminopurine (BAP), kinetin (KIN), thidiazuron (TDZ), gibberellic acid (GA3) and spermidine] were supplemented alone and its combinations for obtaining better results. The best growth frequency response was achieved in the combinations of 1.0 BAP + 0.3 KIN + 1.5 GA3 (mg/L) concentration (7.4 ± 0.9 cm shoot length & 100 % regeneration). Better roots were developed in half-strength B5 medium along with IBA (1.0 mg/L) hormone and exhibits maximum root length (7.0 ± 0.8cm) along with multiple roots (8.8 ± 0.8) at 92 %. The well-developed Plantlets were successfully acclimatized to plastic-cups containing autoclaved sand and garden soil (1:1) and kept undisturbed with plastic cover for maintaining the humidity. The plantlets were watered regularly and maintained at green house
Facile, productive, and cost-effective synthesis of a novel tetrazine-based iron oxide nanoparticle for targeted image contrast agents and nanomedicines
We have developed an operationally simple, time, and cost-effective protocol to produce a novel tetrazine-based iron oxide nanoparticle using commercially available and inexpensive materials. Our protocol proceeds at room temperature and uses hexafluorophosphate azabenzotriazole tetramethyl uronium, a well-known, widely used reagent for the large-scale industrial production of important pharmaceuticals. The nanoparticles obtained have a diameter range between 16 and 21 nm and showed no toxicity against endothelial cell lines. The tetrazine moiety on the nanoparticle surface could potentially allow further attachment of specific targeting vectors by using so-called copper-free click chemistry. We therefore anticipate that our protocol can represent a significant breakthrough in the future development and commercialization of improved, tissue-specific contrast agents and drug delivery for clinical diagnosis, monitoring and therapy of diseases at an asymptomatic stage
Argus: A 16-pixel Millimeter-Wave Spectrometer for the Green Bank Telescope
We report on the development of Argus, a 16-pixel spectrometer, which will enable fast astronomical imaging over the 85–116 GHz band. Each pixel includes a compact heterodyne receiver module, which integrates two InP MMIC low-noise amplifiers, a coupled-line bandpass filter and a sub-harmonic Schottky diode mixer. The receiver signals are routed to and from the multi-chip MMIC modules with multilayer high frequency printed circuit boards, which includes LO splitters and IF amplifiers. Microstrip lines on flexible circuitry are used to transport signals between temperature stages. The spectrometer frontend is designed to be scalable, so that the array design can be reconfigured for future instruments with hundreds of pixels. Argus is scheduled to be commissioned at the Robert C. Byrd Green Bank Telescope in late 2014. Preliminary data for the first Argus pixels are presented
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