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1.
Cancer cell motility is a key phenomenon regulating invasion and metastasis. Focal adhesion kinase (FAK) plays a major role in cellular adhesion and metastasis of various cancers. The relationship between dietary supplementation of calcium and colon cancer has been extensively investigated. However, the effect of calcium (Ca2+) supplementation on calpain-FAK-motility is not clearly understood. We sought to identify the mechanism of FAK cleavage through Ca2+ bound lactate (CaLa), its downstream signaling and role in the motility of human colon cancer cells. We found that treating HCT116 and HT-29 cells with CaLa immediately increased the intracellular Ca2+ (iCa2+) levels for a prolonged period of time. Ca2+ influx induced cleavage of FAK into an N-terminal FAK (FERM domain) in a dose-dependent manner. Phosphorylated FAK (p-FAK) was also cleaved in to its p-N-terminal FAK. CaLa increased colon cancer cells motility. Calpeptin, a calpain inhibitor, reversed the effects of CaLa on FAK and pFAK cleavage in both cancer cell lines. The cleaved FAK translocates into the nucleus and modulates p53 stability through MDM2-associated ubiquitination. CaLa-induced Ca2+ influx increased the motility of colon cancer cells was mediated by calpain activity through FAK and pFAK protein destabilization. In conclusion, these results suggest that careful consideration may be given in deciding dietary Ca2+ supplementation to patient undergoing treatment for metastatic cancer.  相似文献   
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We present a mathematical method for acceleration workspace analysis of cooperating multi-finger robot systems using a model of point-contact with friction. A new unified formulation from dynamic equations of cooperating multi-finger robots is derived considering the force and acceleration relationships between the fingers and the object to be handled. From the dynamic equation, maximum translational and rotational acceleration bounds of an object are calculated under given constraints of contact conditions, configurations of fingers, and bounds on the torques of joint actuators for each finger. Here, the rotational acceleration bounds can be applied as an important manipulability index when the multi-finger robot grasps an object. To verify the proposed method, we used a set of case studies with a simple multi-finger mechanism system. The achievable acceleration boundary in task space can be obtained successfully with the proposed method and the acceleration boundary depends on the configurations of fingers.  相似文献   
4.
A shortcut biological nitrogen removal (SBNR) utilizes the concept of a direct conversion of ammonium to nitrite and then to nitrogen gas. A successful SBNR requires accumulation of nitrite in the system and inhibition of the activity of nitrite oxidizers. A high concentration of free ammonia (FA) inhibits nitrite oxidizers, but unfortunately decreases the ammonium removal rate as well. Therefore, the optimal range of FA concentration is necessary not only to stabilize nitrite accumulation but also to achieve maximum ammonium removal. In order to derive such optimal FA concentrations, the specific substrate utilization rates of ammonium and nitrite oxidizers were measured. The optimal FA concentration range appeared to be 5–10 mg/L for the adapted sludge. The simulated results from the modified inhibition model expressed by FA and ammonium/nitrite concentrations were shown very similar to the experimental results.  相似文献   
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A comparison of the proteome of eight genetically well‐characterized isolates of the Bostrychia radicans (Mont.) Mont./B. moritziana (Sond. ex Kütz.) J. Agardh species complex was undertaken to establish if genetic relationships among them can be determined using proteome data. Genetic distances were calculated on the basis of common and distinct spots in two‐dimensional gel electrophoresis (2‐DE). Proteomes of the male and female plants of each population were compared to analyze the range of genetic difference within an isolate. Haploid male and female plants of the same species had 3.7%–7.1% sex‐specific proteins. The degree of similarity of the proteome was consistent with previous DNA sequence data and sexual compatibility studies between the isolates. Two sexually compatible isolates from Venezuela showed a pair‐wise distance ranging from 0.14 to 0.21. The isolates from Mexico and Venezuela, which were partially compatible, showed a maximum pair‐wise distance of 0.26. A high level of genetic difference was found among isolates that were sexually incompatible. The isolate from Brazil was reproductively isolated from the Mexico and Venezuela isolates and showed a maximum pair‐wise distance of 0.65 and 0.58, respectively. Comparative proteomics may be helpful for studying genetic distances among algal samples, if intraisolate variation (gene expression) can be minimized or tested.  相似文献   
6.
As part of the development of carbon-coated prosthetic devices, the adhesion of thin carbon films to metallic substrates has been studied. The bond strength of carbon films about 5000 A thick on Ti-6A1-4V and stainless steel was measured in a pull test and found to be greater than 4700 psi. Auger electron spectroscopy showed a reactive film/substrate interface. The ultimate bond strength was found to be dependent on the substrate and the deposition parameters.  相似文献   
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Background

To characterize changes in global protein expression in kidneys of transgenic rats overexpressing human selenoprotein M (SelM) in response to increased bioabivility of selenium (Sel), total proteins extracted from kidneys of 10-week-old CMV/hSelM Tg and wild-type rats were separated by 2-dimensional gel electrophoresis and measured for changes in expression.

Results

Ten and three proteins showing high antioxidant enzymatic activity were up- and down-regulated, respectively, in SelM-overexpressing CMV/hSelM Tg rats compared to controls based on an arbitrary 2-fold difference. Up-regulated proteins included LAP3, BAIAP2L1, CRP2, CD73 antigen, PDGF D, KIAA143 homolog, PRPPS-AP2, ZFP313, HSP-60, and N-WASP, whereas down-regulated proteins included ALKDH3, rMCP-3, and STC-1. After Sel treatment, five of the up-regulated proteins were significantly increased in expression in wild-type rats, whereas there were no changes in CMV/hSelM Tg rats. Only two of the down-regulated proteins showed reduced expression in wild-type and Tg rats after Sel treatment.

Conclusions

These results show the primary novel biological evidences that new functional protein groups and individual proteins in kidneys of Tg rats relate to Sel biology including the response to Sel treatment and SelM expression.  相似文献   
9.
Mast cells play important roles in allergic disease and immune defense against parasites. Once activated (e.g. by an allergen), they degranulate, a process that results in the exocytosis of allergic mediators. Modulation of mast cell degranulation by drugs and toxicants may have positive or adverse effects on human health. Mast cell function has been dissected in detail with the use of rat basophilic leukemia mast cells (RBL-2H3), a widely accepted model of human mucosal mast cells3-5. Mast cell granule component and the allergic mediator β-hexosaminidase, which is released linearly in tandem with histamine from mast cells6, can easily and reliably be measured through reaction with a fluorogenic substrate, yielding measurable fluorescence intensity in a microplate assay that is amenable to high-throughput studies1. Originally published by Naal et al.1, we have adapted this degranulation assay for the screening of drugs and toxicants and demonstrate its use here.Triclosan is a broad-spectrum antibacterial agent that is present in many consumer products and has been found to be a therapeutic aid in human allergic skin disease7-11, although the mechanism for this effect is unknown. Here we demonstrate an assay for the effect of triclosan on mast cell degranulation. We recently showed that triclosan strongly affects mast cell function2. In an effort to avoid use of an organic solvent, triclosan is dissolved directly into aqueous buffer with heat and stirring, and resultant concentration is confirmed using UV-Vis spectrophotometry (using ε280 = 4,200 L/M/cm)12. This protocol has the potential to be used with a variety of chemicals to determine their effects on mast cell degranulation, and more broadly, their allergic potential.  相似文献   
10.
Xylose utilization is inhibited by glucose uptake in xylose-assimilating yeasts, including Candida tropicalis, resulting in limitation of xylose uptake during the fermentation of glucose/xylose mixtures. In this study, a heterologous xylose transporter gene (At5g17010) from Arabidopsis thaliana was selected because of its high affinity for xylose and was codon-optimized for functional expression in C. tropicalis. The codon-optimized gene was placed under the control of the GAPDH promoter and was integrated into the genome of C. tropicalis strain LXU1 which is xyl2-disrupted and NXRG (codon-optimized Neurospora crassa xylose reductase) introduced. The xylose uptake rate was increased by 37–73 % in the transporter expression-enhanced strains depending on the glucose/xylose mixture ratio. The recombinant strain LXT2 in 500-mL flask culture using glucose/xylose mixtures showed a xylose uptake rate that was 29 % higher and a xylitol volumetric productivity (1.14 g/L/h) that was 25 % higher than the corresponding rates for control strain LXU1. Membrane protein extraction and Western blot analysis confirmed the successful heterologous expression and membrane localization of the xylose transporter in C. tropicalis.  相似文献   
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