Infinite M1000 PRO - Scientific citations

 ««  «  1  2 3 4 5 6 7  »  »» 1 - 5 from 44

Title Nitric oxide accumulation in Arabidopsis is independent of NOA1 in the presence of sucrose..
Authors Van Ree K, Gehl B, Wassim Chehab E, Tsai YC, Braam J.
Institution Biochemistry and Cell Biology, Rice University, Houston, TX 77005-1892, USA.
Journal Plant J. 2011 Jun 20. doi: 10.1111/j.1365-313X.2011.04680.x.
Abstract Nitric oxide signals diverse responses in animals and plants. Whereas nitric oxide synthesis mechanisms in animals are well understood, how nitric oxide is synthesized and regulated in plants remains controversial.
Text Nitric oxide signals diverse responses in animals and plants. Whereas nitric oxide synthesis mechanisms in animals are well understood, how nitric oxide is synthesized and regulated in plants remains controversial. NOA1 is a circularly permuted GTPase that is important for chloroplast function and is implicated in nitric oxide synthesis. However, the reported consequences of a null mutation in NOA1 are inconsistent. Whereas some studies indicate that the noa1 mutant has severe reductions in nitric oxide accumulation, others report that nitric oxide levels are indistinguishable between noa1 and the wild type. Here, we identify a correlation between the reported ability of noa1 to accumulate nitric oxide with growth on sucrose-supplemented media. We report that noa1 accumulates both basal and salicylic acid-induced nitric oxide only when grown on media containing sucrose. In contrast, nitric oxide accumulation in wild type is largely insensitive to sucrose supplementation. When grown in the absence of sucrose, noa1 has low fumarate, pale green leaves, slow growth and reduced chlorophyll content. These phenotypes are consistent with a defect in chloroplast-derived photosynthate production and are largely rescued by sucrose supplementation. We conclude that NOA1 has a primary role in chloroplast function and that its effects on the accumulation of nitric oxide are likely to be indirect.
Pubmed ID 21689173
Title Lensless CCD-based fluorometer using a micromachined optical Söller collimator .
Authors Balsam J, Ossandon M, Kostov Y, Bruck HA, Rasooly A.
Institution University of Maryland College Park (UMCP), College Park, MD 20742, USA.
Journal Lab Chip. 2011 Mar 7,11(5):941-9. Epub 2011 Jan 17.
Abstract In this paper, we describe a simple charge-coupled device (CCD) based lensless fluorometer with sensitivity in the range of current ELISA plate readers. In our lensfree fluorometer, a multi-wavelength LED light source was used for fluorophore excitation.
Text To collimate the light, we developed a simple optical Söller collimator based on a "stack of pinholes" (a stack of black PMMA with array of pinholes machined with laser) enabling the light to be collimated from the LED through the filters and the assay's microfluidics directly onto the CCD without a lens. The elimination of the lens that is used in almost all other current CCD based detection systems has four major advantages: (1) It simplifies the device design and fabrication while reducing cost. (2) It reduces the distance between the sample and the measuring device (without a lens the distance needed to focus the image on the CCD is reduced and the fluorometer can be more compact). (3) It couples the CCD and the detected surface by using an optical Söller Collimator which allows the use of filters for fluorescence detection. (4) It also uncouples the CCD and the microfluidics to enable the use of interchangeable fluidics while protecting the delicate CCD. The lensless CCD-based fluorometer is capable of detecting 16 samples simultaneously, and was used for in vitro detection of botulinum neurotoxin serotype A (BoNT-A) activity with a FRET assay that measures cleavage of a fluorophore-tagged peptide substrate specific for BoNT-A (SNAP-25) by the toxin light chain (LcA). The limit of detection (LOD) of our lensless fluorometer is 1.25 nM, which is similar to the LOD of a modern ELISA plate reader. Combined with microfluidics, this simple low cost point-of-care (POC) medical diagnostic system may be useful for the performance of many other complex medical diagnostic assays without a laboratory and thus potentially enhancing the accessibility and the quality of health care delivery in underserved populations.
Pubmed ID 21243150
Title Development of Vaccinia reporter viruses for rapid, high content analysis of viral function at all stages of gene expression .
Authors Dower K, Rubins KH, Hensley LE, Connor JH.
Institution Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
Journal Antiviral Res. 2011 Jul,91(1):72-80. doi: 10.1016/j.antiviral.2011.04.014. Epub 2011 May 5
Abstract Vaccinia virus is the prototypical orthopoxvirus of Poxviridae, a family of viruses that includes the human pathogens Variola (smallpox) and Monkeypox.
Text Core viral functions are conserved among orthopoxviruses, and consequently Vaccinia is routinely used to study poxvirus biology and screen for novel antiviral compounds. Here we describe the development of a series of fluorescent protein-based reporter Vaccinia viruses that provide unprecedented resolution for tracking viral function. The reporter viruses are divided into two sets: (1) single reporter viruses that utilize temporally regulated early, intermediate, or late viral promoters, and (2) multi-reporter viruses that utilize multiple temporally regulated promoters. Promoter and reporter combinations were chosen that yielded high signal-to-background for stage-specific viral outputs. We provide examples for how these viruses can be used in the rapid and accurate monitoring of Vaccinia function and drug action.
Pubmed ID 21569797
Title Molecular determinants involved in activation of caspase 7.
Authors Boucher D, Blais V, Drag M, Denault JB.
Institution Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4
Journal Biosci Rep. 2011 Mar 2,31(4):283-94.
Abstract During apoptosis, initiator caspases (8, 9 and 10) activate downstream executioner caspases (3, 6 and 7) by cleaving the IDC (interdomain connector) at two sites. Here, we demonstrate that both activation sites, site 1 and site 2, of caspase 7 are suboptimal for activation by initiator caspases 8 and 9 in cellulo, and in vitro using recombinant proteins and activation kinetics.
Text Indeed, when both sites are replaced with the preferred motifs recognized by either caspase 8 or 9, we found an up to 36-fold improvement in activation. Moreover, cleavage at site 1 is preferred to site 2 because of its location within the IDC, since swapping sites does not lead to a more efficient activation. We also demonstrate the important role of Ile195 of site 1 involved in maintaining a network of contacts that preserves the proper conformation of the active enzyme. Finally, we show that the length of the IDC plays a crucial role in maintaining the necessity of proteolysis for activation. In fact, although we were unable to generate a caspase 7 that does not require proteolysis for activity, shortening the IDC of the initiator caspase 8 by four residues was sufficient to confer a requirement for proteolysis, a key feature of executioner caspases. Altogether, the results demonstrate the critical role of the primary structure of caspase 7's IDC for its activation and proteolytic activity.
Pubmed ID 20942802
Title Dynamics of coregulator-induced conformational perturbations in androgen receptor ligand binding domain .
Authors Zakharov MN, Pillai BK, Bhasin S, Ulloor J, Istomin AY, Guo C, Godzik A, Kumar R, Jasuja R.
Institution Section of Endocrinology, Boston University School of Medicine, 670 Albany St., Boston, MA 02118, USA
Journal Mol Cell Endocrinol. 2011 Jul 20,341(1-2):1-8. Epub 2011 May 14.
Abstract Androgen receptor (AR) coregulators modulate ligand-induced gene expression in a tissue specific manner. The molecular events that follow coactivator binding to AR and the mechanisms that govern the sequence-specific effects of AR coregulators are poorly understood
Text Using consensus coactivator sequence D11-FxxLF and biophysical techniques, we show that coactivator association is followed by conformational rearrangement in AR ligand binding domain (AR-LBD) that is enthalpically and entropically favorable with activation energy of 29.8±4.2kJ/mol. Further characterization of ARA70 and SRC3-1 based consensus sequences reveal that each coactivator induces a distinct conformational state in the dihydrotestosterone:AR-LBD:coactivator complex. Complementary computational modeling revealed that coactivator induced specific alterations in the backbone flexibility of AR-LBD distant from the site of coactivator binding and that the intramolecular rearrangements in AR-LBD backbone induced by the two coactivator peptides were different. These data suggest that coactivators may impart specificity in the transcriptional machinery by changing the steady-state conformation of AR-LBD. These data provide direct evidence that even in the presence of same ligand, AR-LBD can occupy distinct conformational states depending on its interactions with specific coactivators in the tissues. We posit that this coactivator-specific conformational gating may then dictate subsequent binding partners and interaction/affinity for the DNA-response elements.
Pubmed ID 21605623
 ««  «  1  2 3 4 5 6 7  »  »» 1 - 5 from 44

Infinite M1000 PRO

Product Details
Technical Literature / Download
Scientific Citations

Related Topics
Comparison of Absorbance Readers
Comparison of Multimode Readers
List of all application notes
Application Guide

Get in touch with us ...
Do you want to know more?

Need help?

Have other questions?

Request a quote