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101.
102.
Human serum does contain a high molecular weight hepatocyte growth factor: studies pre- and post-hepatic resection 总被引:10,自引:0,他引:10
C Selden R Johnstone H Darby S Gupta H J Hodgson 《Biochemical and biophysical research communications》1986,139(1):361-366
Levels of a high molecular weight hepatotrophin were measured in human serum taken from patients before and 24 hours after undergoing major hepatic resection. In in-vitro rat hepatocyte cultures a 'hepatotrophin' enriched fraction of human serum induced the incorporation of tritiated thymidine into DNA in both pre and post-operative patients. Levels after hepatic resection were 2-3 fold higher than those achieved at the same protein concentration before operation in the same patient. The hepatotrophic factor had an apparent molecular weight of approximately 150,000 daltons, and was an anionic protein. 相似文献
103.
Antibody-mediated targeting of liposomes to red cells in vivo 总被引:2,自引:0,他引:2
Covalent attachment of anti-rat erythrocyte F(ab')2 to liposomes specifically enhanced their binding to rat erythrocytes in vivo and reduced their uptake by the liver. Furthermore, at least 20-30% of the cell-bound liposomes delivered their contents to the cells. Besides, the liposome binding did not affect the survival time of the target cells at least up to 3 h in the blood circulation. These results demonstrate for the first time that liposomes can be successfully targeted to cells other than liver cells in vivo. 相似文献
104.
Previous workers have shown that oligosaccharides and glycopeptides can be separated by electrophoresis in buffers containing borate ions. However, normal fluorography of tritium-labeled structures cannot be performed because the glycans are soluble and can diffuse during equilibration with scintillants. This problem has been circumvented by equilibration of the gel with 2,5-diphenyloxazole (PPO) prior to electrophoresis. The presence of PPO in the gel during electrophoresis does not alter mobility of the glycopeptides and oligosaccharides. After electrophoresis, the gel is simply dried and fluorography performed. This allows sensitive and precise comparisons of labeled samples in parallel lanes of a slab gel and, since mobilities are highly reproducible, between different gels. The procedure is preparative in that after fluorography the gel bands can be quantitatively eluted for further study, without any apparent modification by the procedure. In this report, the procedure is illustrated by fractionation of both neutral and anionic glycopeptides produced by the cellular slime mold Dictyostelium discoideum. 相似文献
105.
The method for two-dimensional gel electrophoresis of J. Klose and M. Feller [(1981) Electrophoresis 2, 12-24] has been simplified by reducing the thickness of the gels from 3.5 to 1.1 mm for isoelectric focusing gels and from 3.5 to 0.84 mm for sodium dodecyl sulfate slab gels. Thin gels need less reagents and smaller sample volumes. Cooling of the thin gels during electrophoresis is more effective, which allows the use of higher electric power. Therefore, less time is required for an electrophoretic run (approx 4 h). The resolution increases due to the smaller size of the spots. The time required for staining the gels is reduced from at least 3 days to about 1 h. The method has been tested with a protein sample from the filamentous fungus Fusarium solani. 相似文献
106.
Sodium hydroxide and its derivatives are used as pulping reagents, wherein the spent NaOH is recovered in salt form and reused. In this study, use of low concentration NaOH (1–5%) in pretreatment of corn stover and hybrid poplar was investigated. It was done with the understanding that NaOH can be recovered. One of the main objectives in this study is to explore the potential of H2O2 with NaOH for pretreatment of high lignin substrate such as hybrid poplar. Pretreatment time has not been optimized in this study but held constant at 24 h. Corn stover, after treatment with NaOH under moderate conditions, attains near quantitative glucan digestibility. On the other hand, hybrid poplar requires treatment at higher temperature and NaOH concentration to attain acceptable level of digestibility. Supplementation of hydrogen peroxide in the pretreatment significantly raises delignification and digestibility of hybrid poplar. It was also helpful in retaining the carbohydrates in the treated solids. Retention of hemicellulose after pretreatment provides a significant economic benefit as it eliminates the need for detoxifying hemicellulose sugars. As the residual xylan remaining after pretreatment is an impediment to enzymatic digestion of glucan, supplementation of xylanase has significantly increased the digestibility of glucan as well as xylan of the treated hybrid poplar. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010 相似文献
107.
Gupta P Singh A Chauhan V Bhatnagar R 《Biochemical and biophysical research communications》2001,280(1):158-163
Anthrax toxin is a complex of protective antigen (PA, 735 aa), lethal factor (LF, 776 aa), and edema factor (EF, 767 aa). PA binds to cell surface receptors and is cleaved by cell surface proteases into PA63, while LF and EF compete for binding to PA63. The PA63-LF/EF complex is internalized into the cytosol and causes different pathogenic responses in animals and cultured cells. 1-300 amino acid residues of LF have been viewed as the region responsible for the high affinity binding of LF to PA. Amino acid analysis of LF and EF revealed a common stretch of 7 amino acids (147VYYEIGK153). In the present study, each amino acid of this stretch was replaced by alanine at a time. Y148A, Y149A, I151A, and K153A mutants were found to be deficient in their ability to lyse J774A.1 cells and their binding ability to PA63 was drastically reduced. We propose that these four amino acids play a crucial role in the process of binding of LF to PA63. 相似文献
108.
Liu J Rumsey JW Das M Molnar P Gregory C Riedel L Hickman JJ 《In vitro cellular & developmental biology. Animal》2008,44(5-6):162-168
We are attempting to recreate a stretch reflex circuit on a patterned Bio-MEMS (bio-microelectromechanical systems) chip with deflecting micro-cantilevers. The first steps to recreate this system is to be able to grow individual components of the circuit (sensory neuron, motoneuron, skeletal muscle, and muscle spindle) on a patternable, synthetic substrate coating the MEMS device. Sensory neurons represent the afferent portion of the stretch reflex arc and also play a significant role in transmitting the signal from the muscle spindle to the spinal cord motoneurons. We have utilized a synthetic silane substrate N-1[3-(trimethoxysilyl) propyl) diethylenetriamine (DETA) on which to grow and pattern the cells. DETA forms a self-assembled monolayer on a variety of silicon substrates, including glass, and can be patterned using photolithography. In this paper, we have evaluated the growth of sensory neurons on this synthetic silane substrate. We have investigated the immunocytochemical and electrophysiological properties of the sensory neurons on DETA and compared the resultant properties with a biological control substrate (ornithine/laminin). Immunocytochemical studies revealed the survival and growth of all three subtypes of sensory neurons: trkA, trkB, and trkC on both surfaces. Furthermore, whole-cell patch clamp recordings were used to study the electrophysiological properties of the sensory neurons on the two surfaces. There were no significant differences in the electrical properties of the neurons grown on either surface. This is the first study analyzing the immunocytochemical and electrophysiological properties of sensory neurons grown long-term in a completely defined environment and on a nonbiological substrate. 相似文献
109.
110.
Studies of RNA-binding peptides, and recent combinatorial library experiments in particular, have demonstrated that diverse peptide sequences and structures can be used to recognize specific RNA sites. The identification of large numbers of sequences capable of binding to a particular site has provided extensive phylogenetic information used to deduce basic principles of recognition. The high frequency at which RNA-binding peptides are found in large sequence libraries suggests plausible routes to evolve sequence-specific binders, facilitating the design of new binding molecules and perhaps reflecting characteristics of natural evolution. 相似文献