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151.
Paul R. Sanberg Dong‐Hyuk Park Nicole Kuzmin‐Nichols Eduardo Cruz Nelson Americo Hossne Jr Enio Buffolo Alison E. Willing 《Journal of cellular and molecular medicine》2010,14(3):553-563
Neovascularization is an integral process of inflammatory reactions and subsequent repair cascades in tissue injury. Monocytes/macrophages play a key role in the inflammatory process including angiogenesis as well as the defence mechanisms by exerting microbicidal and immunomodulatory activity. Current studies have demonstrated that recruited monocytes/macrophages aid in regulating angiogenesis in ischemic tissue, tumours and chronic inflammation. In terms of neovascularization followed by tissue regeneration, monocytes/macrophages should be highly attractive for cell-based therapy compared to any other stem cells due to their considerable advantages: non-oncogenic, non-teratogenic, multiple secretary functions including pro-angiogenic and growth factors, straightforward cell harvesting procedure and non-existent ethical controversy. In addition to adult origins such as bone marrow or peripheral blood, umbilical cord blood (UCB) can be a potential source for autologous or allogeneic monocytes/macrophages. Especially, UCB monocytes should be considered as the first candidate owing to their feasibility, low immune rejection and multiple characteristic advantages such as their anti-inflammatory properties by virtue of their unique immune and inflammatory immaturity, and their pro-angiogenic ability. In this review, we present general characteristics and potential of monocytes/macrophages for cell-based therapy, especially focusing on neovascularization and UCB-derived monocytes. 相似文献
152.
Jillienne C. Touchette Deepa Ajit Michael R. Nichols 《Archives of biochemistry and biophysics》2010,494(2):192-2071
A signature feature of Alzheimer’s disease is the accumulation of plaques, composed of fibrillar amyloid-β protein (Aβ), in the brain parenchyma. Structural models of Aβ fibrils reveal an extensive β-sheet network with a hydrophobic core extending throughout the fibril axis. In this study, phenylalanines in the Aβ(1-40) sequence were substituted with tryptophan residues at either position 4 (F4W) or 19 (F19W) to probe the fibril environment. The F4W substitution did not alter self-assembly kinetics, while the F19W change slightly lengthened the lag phase without hindering fibril formation. The tryptophan fluorescence of Aβ(1-40) F19W, but not Aβ(1-40) F4W, underwent a marked blue shift during fibril formation and this shift was temporally correlated with thioflavin T binding. Isolated Aβ(1-40) F19W fibrils exhibited the largest fluorescence blue shifts consistent with W19 insertion into the Aβ(1-40) fibril inner core and direct probing of the substantially hydrophobic environment therein. 相似文献
153.
J S Nichols H LeVine G F Smith D M Wypij J S Wiseman 《Journal of biochemical and biophysical methods》1992,25(2-3):173-184
Bovine cerebellar membranes immobilized on 96-well microtiter plates provide receptors for 125I-labeled endothelin-1 as the basis for a competitive binding assay. Adsorption of the membranes to a surface does not significantly alter the ligand-receptor interaction and reduces non-specific binding to 3-7% of total binding compared to 10-20% for a filtration technique. Considerable savings in reagents are realized since assays can be performed in 100 microliter volumes with only 10-20 micrograms of membrane protein. The 96-well format allows the rapid quantitation of large numbers of samples, and the assay is especially attractive in that it utilizes readily available reagents and equipment without the need for specific antibodies. The endothelin-receptor-based assay may be used to measure conversion of big endothelin-1 to endothelin-1 in aqueous assays. Since the presence of serum does not affect this method, tissue culture medium may be directly analyzed for endothelin production by cultured cells. All three isoforms of endothelin are detected, and the specificity of the receptor is retained since fragments and precursor forms of endothelin are not recognized. In cases where multiple endothelin isoforms may be present or where specificity of binding is in question, this assay may be used in conjunction with high pressure liquid chromatography to distinguish active peptides. 相似文献
154.
155.
Cook N Nichols RA Wilkinson N Paton CA Barker K Smith HV 《Applied and environmental microbiology》2007,73(22):7388-7391
We report a method for detecting Giardia duodenalis cysts on lettuce, which we subsequently use to examine salad products for the presence of Giardia cysts and Cryptosporidium oocysts. The method is based on four basic steps: extraction of cysts from the foodstuffs, concentration of the extract and separation of the cysts from food materials, staining of the cysts to allow their visualization, and identification of cysts by microscopy. The concentration and separation steps are performed by centrifugation, followed by immunomagnetic separation using proprietary kits. Cyst staining is also performed using proprietary reagents. The method recovered 46.0% +/- 19.0% (n = 30) of artificially contaminating cysts in 30 g of lettuce. We tested the method on a variety of commercially available natural foods, which we also seeded with a commercially available internal control, immediately prior to concentration of the extract. Recoveries of the Texas Red-stained Giardia cyst and Cryptosporidium oocyst internal controls were 36.5% +/- 14.3% and 36.2% +/- 19.7% (n = 20), respectively. One natural food sample of organic watercress, spinach, and rocket salad contained one Giardia cyst 50 g(-1) of sample as an indigenous surface contaminant. 相似文献
156.
Zhou XR Robert SS Petrie JR Frampton DM Mansour MP Blackburn SI Nichols PD Green AG Singh SP 《Phytochemistry》2007,68(6):785-796
The marine microalga Pavlova salina produces lipids containing approximately 50% omega-3 long chain polyunsaturated fatty acids (LC-PUFA) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Three cDNA sequences, designated PsD4Des, PsD5Des, PsD8Des, were isolated from P. salina and shown to encode three front-end desaturases with Delta4, Delta5 and Delta8 specificity, respectively. Southern analysis indicated that the P. salina genome contained single copies of all three front-end fatty acid desaturase genes. When grown at three different temperatures, analysis of fatty acid profiles indicated P. salina desaturation conversions occurred with greater than 95% efficiency. Real-Time PCR revealed that expression of PsD8Des was higher than for the other two genes under normal growth conditions, while PsD5Des had the lowest expression level. The deduced amino acid sequences from all three genes contained three conserved histidine boxes and a cytochrome b(5) domain. Sequence alignment showed that the three genes were homologous to corresponding desaturases from other microalgae and fungi. The predicted activities of these three front-end desaturases leading to the synthesis of LC-PUFA were also confirmed in yeast and in higher plants. 相似文献
157.
Erpenbeck D Nichols SA Voigt O Dohrmann M Degnan BM Hooper JN Wörheide G 《Journal of molecular evolution》2007,64(5):543-557
Many rDNA molecular phylogenetic studies result in trees that are incongruent to either alternative gene tree reconstructions
and/or morphological assumptions. One reason for this outcome might be the application of suboptimal phylogenetic substitution
models. While the most commonly implemented models describe the evolution of independently evolving characters fairly well,
they do not account for character dependencies such as rRNA strands that form a helix in the ribosome. Such nonindependent
sites require the use of models that take into account the coevolution of the complete nucleotide pair (doublet). We analyzed
28S rDNA (LSU) demosponge phylogenies using a “doublet” model for pairing sites (rRNA-helices) and compared our findings with
the results of “standard” approaches using Bayes factors. We demonstrate that paired and unpaired sites of the same gene result
in different reconstructions and that usage of a doublet model leads to more reliable demosponge trees. We show the influence
of more sophisticated models on phylogenetic reconstructions of early-branching metazoans and the phylogenetic relationships
of demosponge orders.
[Reviewing Editor: Dr. Rasmus Nielsen] 相似文献
158.
Nichols RA Dengler AF Nakagawa EM Bashkin M Paul BT Wu J Khan GM 《The Journal of biological chemistry》2007,282(49):36102-36111
Calcium levels in the presynaptic nerve terminal are altered by several pathways, including voltage-gated Ca(2+) channels, the Na(+)/Ca(2+) exchanger, Ca(2+)-ATPase, and the mitochondria. The influx pathway for homeostatic control of [Ca(2+)](i) in the nerve terminal has been unclear. One approach to detecting the pathway that maintains internal Ca(2+) is to test for activation of Ca(2+) influx following Ca(2+) depletion. Here, we demonstrate that a constitutive influx pathway for Ca(2+) exists in presynaptic terminals to maintain internal Ca(2+) independent of voltage-gated Ca(2+) channels and Na(+)/Ca(2+) exchange, as measured in intact isolated nerve endings from mouse cortex and in intact varicosities in a neuronal cell line using fluorescence spectroscopy and confocal imaging. The Mg(2+) and lanthanide sensitivity of the influx pathway, in addition to its pharmacological and short hairpin RNA sensitivity, and the results of immunostaining for transient receptor potential (TRP) channels indicate the involvement of TRPC channels, possibly TRPC5 and TRPC1. This constitutive Ca(2+) influx pathway likely serves to maintain synaptic function under widely varying levels of synaptic activity. 相似文献
159.
DSL ligand endocytosis physically dissociates Notch1 heterodimers before activating proteolysis can occur
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Nichols JT Miyamoto A Olsen SL D'Souza B Yao C Weinmaster G 《The Journal of cell biology》2007,176(4):445-458
Cleavage of Notch by furin is required to generate a mature, cell surface heterodimeric receptor that can be proteolytically activated to release its intracellular domain, which functions in signal transduction. Current models propose that ligand binding to heterodimeric Notch (hNotch) induces a disintegrin and metalloprotease (ADAM) proteolytic release of the Notch extracellular domain (NECD), which is subsequently shed and/or endocytosed by DSL ligand cells. We provide evidence for NECD release and internalization by DSL ligand cells, which, surprisingly, did not require ADAM activity. However, losses in either hNotch formation or ligand endocytosis significantly decreased NECD transfer to DSL ligand cells, as well as signaling in Notch cells. Because endocytosis-defective ligands bind hNotch, but do not dissociate it, additional forces beyond those produced through ligand binding must function to disrupt the intramolecular interactions that keep hNotch intact and inactive. Based on our findings, we propose that mechanical forces generated during DSL ligand endocytosis function to physically dissociate hNotch, and that dissociation is a necessary step in Notch activation. 相似文献
160.