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111.
Wandelt B Mielniczak A Turkewitsch P Darling GD Stranix BR 《Biosensors & bioelectronics》2003,18(4):465-471
In aqueous solution, 4-[4-(dimethylamino)styryl]pyridine (DMASP) derivatives displayed dual fluorescence, in which excitation at either 469 or 360 nm produced an emission band near 600 nm. Increasing the viscosity of the environment intensified the fluorescence emission obtained at the longer wavelength of excitation, whereas the emission at the lower wavelength of excitation showed little change in intensity. Thus, using the ratio of the 600 nm emission obtained by exciting at 469 nm to that obtained with 360 nm excitation, it is possible to obtain a value related to the local viscosity that does not depend on the system parameters. The fluorescence emission of the dye in aqueous solution, as well as in living cells, is well suited for use with visible fluorescence spectroscopy. The N-carboxymethyl butyl ester DMASP derivative (1) was found to be irreversibly loaded into living smooth muscle cells, presumably because it is hydrolyzed by cellular esterases, transforming it into a membrane-impermeable fluorescent carboxylate DMASP derivative. (2) After calibrating 2 against glycerol/water and sucrose/water mixtures of known viscosity, the fluorescence ratio generated from cultured smooth muscle cells in dual-excitation mode gave an average intracellular viscosity of 4.5 cP. This value corresponds to those reported in the literature. 相似文献
112.
Alice R. Arredondo Brent L. Dorval Alexander M. Klibanov Kim Lewis 《Biotechnology letters》2000,22(7):547-550
A filtration flow-through design was used to develop the rapid immunodetection of Escherichia coli. Polyclonal anti-E. coli IgG was conjugated to small, 0.8 Blue latex beads. Cells were mixed with conjugated beads in the presence of anti-E. coli monoclonal IgM. The suspension was then filtered through a 5 nitrocellulose membrane. The cell-containing complexes were effectively collected on the filter, forming a blue spot. The method produced reliable detection of E. coli at a concentration of 105 cells ml–1, which is a current benchmark figure for urinary tract infection (UTI) diagnosis. 相似文献
113.
Jason E. Bond Brent D. Opell 《Evolution; international journal of organic evolution》1998,52(2):403-414
We combine statistical and phylogenetic approaches to test the hypothesis that adaptive radiation and key innovation have contributed to the diversity of the order Araneae. The number of unbalanced araneid clades (those whose species numbers differ by 90% or more) exceeds the number predicted by a null Markovian model. The current phylogeny of spider families contains 74 bifurcating nodes, of which 31 are unbalanced. As this is significantly more than the 14.8 expected unbalanced nodes, some of the diversity within the Araneae can be attributed to some deterministic cause (e.g., adaptive radiation). One of the more highly unbalanced (97%) bifurcations divides the orb-weaving spiders into the Deinopoidea and the larger Araneoidea. A simple statistical model shows that the inequality in diversity between the Deinopoidea and the Araneoidea is significant, and that it is associated with the replacement of primitive cribellar capture thread by viscous adhesive thread and a change from a horizontal to a vertical orb-web orientation. These changes improve an orb-web's ability to intercept and retain prey and expand the adaptive zone that orb-weaving spiders can occupy and are, therefore, considered to be “key innovations.” 相似文献
114.
The correlation of protein structure and evolution of a protein-coding gene: phylogenetic inference using cytochrome oxidase III 总被引:1,自引:1,他引:0
Discriminating phylogenetic signal from noise in DNA sequence data is a
difficult problem in phylogenetic inference at higher systematic levels.
For protein-coding genes, noise at synonymous (silent) positions can be
filtered by deleting entire codon positions or types of change at a codon
position. This method is not appropriate for replacement sites, because
changes at each site within a codon may not be independent. This research
presents a method using information from protein structure to evaluate
variation in replacement sites. Analysis of the correlation of amino acid
variation with protein structure identified rapidly evolving codons in the
COIII gene. In a series of phylogenetic analyses attempting to recover a
known set of vertebrate relationships, downweighting these labile codons
produced the most accurate results. Structural correlates of variable and
invariant residues identified in this study can be used to increase the
accuracy of models used for phylogenetic inference. Viewing amino acid
variation within a phylogenetic framework provided insight into residue
changes important in the secondary and tertiary structures of the molecule,
changes that were correlated between pairs of neighboring residues or
between residues in neighboring helices.
相似文献
115.
As part of a behavioral intervention program that identifies and treats individual nonhuman primates exhibiting abnormal behavior, five individually housed pigtail macaques (Macaca nemestrina) were provided with multiple cage toys in an effort to reduce high levels of abnormal behavior. Ten 30-min observations of each subject were conducted during the baseline condition and again after novel toys were presented, both loose inside the cage and attached to the outside of the cage. The new toys were used during 27% of the observation time. Kong Toys were used most consistently by the macaques during the 5-week observation period. Significant decreases in abnormal behavior and cage-directed behavior, as well as significantly increased enrichment use, were evident after the toys were added. Several of the toys were destroyed quickly, and individual differences were evident in the levels of enrichment use and abnormal behavior. Providing multiple manipulable toys as enrichment for pigtail macaques was effective in reducing abnormal behavior and was an important part of an environmental enrichment program for monkeys who could not be housed socially. 相似文献
116.
117.
Asma Iqbal Mahmoud Labib Darija Muharemagic Syed Sattar Brent R. Dixon Maxim V. Berezovski 《PloS one》2015,10(9)
There are currently no standard methods for the detection of Cryptosporidium spp., or other protozoan parasites, in foods, and existing methods are often inadequate, with low and variable recovery efficiencies. Food testing is difficult due to the low concentrations of parasites, the difficulty in eluting parasites from some foods, the lack of enrichment methods, and the presence of PCR inhibitors. The main objectives of the present study were to obtain DNA aptamers binding to the oocyst wall of C. parvum, and to use the aptamers to detect the presence of this parasite in foods. DNA aptamers were selected against C. parvum oocysts using SELEX (Systematic Evolution of Ligands by EXponential enrichment). Ten rounds of selection led to the discovery of 14 aptamer clones with high affinities for C. parvum oocysts. For detecting parasite-bound aptamers, a simple electrochemical sensor was employed, which used a gold nanoparticle-modified screen-printed carbon electrode. This aptasensor was fabricated by self-assembling a hybrid of a thiolated ssDNA primer and the anti- C. parvum aptamer. Square wave voltammetry was employed to quantitate C. parvum in the range of 150 to 800 oocysts, with a detection limit of approximately 100 oocysts. The high sensitivity and specificity of the developed aptasensor suggests that this novel method is very promising for the detection and identification of C. parvum oocysts on spiked fresh fruits, as compared to conventional methods such as microscopy and PCR. 相似文献
118.
Alessandra Cesano Cheryl L. Willman Kenneth J. Kopecky Urte Gayko Santosh Putta Brent Louie Matt Westfall Norman Purvis David C. Spellmeyer Carol Marimpietri Aileen C. Cohen James Hackett Jing Shi Michael G. Walker Zhuoxin Sun Elisabeth Paietta Martin S. Tallman Larry D. Cripe Susan Atwater Frederick R. Appelbaum Jerald P. Radich 《PloS one》2015,10(4)
Single-cell network profiling (SCNP) data generated from multi-parametric flow cytometry analysis of bone marrow (BM) and peripheral blood (PB) samples collected from patients >55 years old with non-M3 AML were used to train and validate a diagnostic classifier (DXSCNP) for predicting response to standard induction chemotherapy (complete response [CR] or CR with incomplete hematologic recovery [CRi] versus resistant disease [RD]). SCNP-evaluable patients from four SWOG AML trials were randomized between Training (N = 74 patients with CR, CRi or RD; BM set = 43; PB set = 57) and Validation Analysis Sets (N = 71; BM set = 42, PB set = 53). Cell survival, differentiation, and apoptosis pathway signaling were used as potential inputs for DXSCNP. Five DXSCNP classifiers were developed on the SWOG Training set and tested for prediction accuracy in an independent BM verification sample set (N = 24) from ECOG AML trials to select the final classifier, which was a significant predictor of CR/CRi (area under the receiver operating characteristic curve AUROC = 0.76, p = 0.01). The selected classifier was then validated in the SWOG BM Validation Set (AUROC = 0.72, p = 0.02). Importantly, a classifier developed using only clinical and molecular inputs from the same sample set (DXCLINICAL2) lacked prediction accuracy: AUROC = 0.61 (p = 0.18) in the BM Verification Set and 0.53 (p = 0.38) in the BM Validation Set. Notably, the DXSCNP classifier was still significant in predicting response in the BM Validation Analysis Set after controlling for DXCLINICAL2 (p = 0.03), showing that DXSCNP provides information that is independent from that provided by currently used prognostic markers. Taken together, these data show that the proteomic classifier may provide prognostic information relevant to treatment planning beyond genetic mutations and traditional prognostic factors in elderly AML. 相似文献
119.
Maria P. Rebollo Khalfan A. Mohammed Brent Thomas Shaali Ame Said Mohammed Ali Jorge Cano Alba Gonzalez Escalada Moses J. Bockarie 《PLoS neglected tropical diseases》2015,9(3)
BackgroundLymphatic filariasis (LF) is targeted for elimination through annual mass drug administration (MDA) for 4–6 years. In 2006, Zanzibar stopped MDA against LF after five rounds of MDA revealed no microfilaraemic individuals during surveys at selected sentinel sites. We asked the question if LF transmission was truly interrupted in 2006 when MDA was stopped.ConclusionsOur findings indicated ongoing transmission of LF on Pemba in 2012. Moreover, we presented evidence from previous studies that LF transmission was also active on Unguja shortly after stopping MDA in 2006. Based on these observations the government of Zanzibar decided to resume MDA against LF on both islands in 2013. 相似文献
120.
Assessing biodiversity and endemism using phylogenetic methods across multiple taxonomic groups
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Carlos E. González‐Orozco Brent D. Mishler Joseph T. Miller Shawn W. Laffan Nunzio Knerr Peter Unmack Arthur Georges Andrew H. Thornhill Dan F. Rosauer Bernd Gruber 《Ecology and evolution》2015,5(22):5177-5192
Identifying geographical areas with the greatest representation of the tree of life is an important goal for the management and conservation of biodiversity. While there are methods available for using a single phylogenetic tree to assess spatial patterns of biodiversity, there has been limited exploration of how separate phylogenies from multiple taxonomic groups can be used jointly to map diversity and endemism. Here, we demonstrate how to apply different phylogenetic approaches to assess biodiversity across multiple taxonomic groups. We map spatial patterns of phylogenetic diversity/endemism to identify concordant areas with the greatest representation of biodiversity across multiple taxa and demonstrate the approach by applying it to the Murray–Darling basin region of southeastern Australia. The areas with significant centers of phylogenetic diversity and endemism were distributed differently for the five taxonomic groups studied (plant genera, fish, tree frogs, acacias, and eucalypts); no strong shared patterns across all five groups emerged. However, congruence was apparent between some groups in some parts of the basin. The northern region of the basin emerges from the analysis as a priority area for future conservation initiatives focused on eucalypts and tree frogs. The southern region is particularly important for conservation of the evolutionary heritage of plants and fishes. 相似文献