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241.
Yegor Rabets Matilda Backholm Kari Dalnoki-Veress William S. Ryu 《Biophysical journal》2014,107(8):1980-1987
With a simple and versatile microcantilever-based force measurement technique, we have probed the drag forces involved in Caenorhabditis elegans locomotion. As a worm crawls on an agar surface, we found that substrate viscoelasticity introduces nonlinearities in the force-velocity relationships, yielding nonconstant drag coefficients that are not captured by original resistive force theory. A major contributing factor to these nonlinearities is the formation of a shallow groove on the agar surface. We measured both the adhesion forces that cause the worm’s body to settle into the agar and the resulting dynamics of groove formation. Furthermore, we quantified the locomotive forces produced by C. elegans undulatory motions on a wet viscoelastic agar surface. We show that an extension of resistive force theory is able to use the dynamics of a nematode’s body shape along with the measured drag coefficients to predict the forces generated by a crawling nematode. 相似文献
242.
Joseph L. Melnick Janet S. Butel Satvir S. Tevethia Nilambar Biswal Matilda Benyesh-Melnick 《In vitro cellular & developmental biology. Plant》1971,6(5):349-354
Summary This paper describes some current work pertaining to transformation of cells by oncogenic viruses.
Part I includes: (1) the effect of a deoxyribonucleic acid (DNA) tumor virus (SV40) on the antigenic characteristics of transformed
cells; (2) in vitro and in vivo methods of detecting virus-specific surface antigens; (3) the role that the host cell may
play in the expression of virus-coded antigens; and (4) the presence of virus-induced antigens as a possible mechanism of
the apparent nononcogenicity of certain virus variants.
Part II discusses (1) the physicochemical properties of the nucleic acid of a ribonucleic acid (RNA) tumor virus-the Moloney
sarcoma-leukemia virus (MSV-MLV) complex —(2) a preliminary analysis of viral RNA replication in cells transformed by MSV-MLV,
and (3) application to human tumors.
Supported in part by Research Grant CA 04600 and by Research Contract PH 43-68-678 within the Special Virus-Cancer Program,
National Cancer Institute, National Institutes of Health.
Recipient of Research Career Development Award 5-K3-CA 38,614 from the National Cancer Institute, National Institutes of Health 相似文献
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244.
Matilda H. -C. Sheng L. Janette Taper Hugo Veit Hao Qian Sanford J. Ritchey K. -H. William Lau 《Biological trace element research》2001,82(1-3):109-123
This study investigated whether boron would enhance the ability of 17beta-estradiol (E2) or parathyroid hormone (PTH) to improve bone quality in ovariectomized OVX rats. Adult OVX rats were treated for 5 wk with vehicle, boron (5 ppm as boric acid), E2 (30 microg/kg/d, sc), PTH (60 microg/kg/d, sc), or a combination of boron and E2 or PTH, respectively. The E2 treatment corrected many adverse effects of OVX on bone quality, increased bone Ca, P, and Mg contents, and decreased trabecular plate separation. Dietary boron supplementation had no effects on these bone parameters in OVX rats. When OVX rats were treated with boron and E2 together, trabecular bone volume (Tb.BS/TV) and plate density were increased significantly more than that caused by E2 alone. The boron and E2 combination also increased trabecular bone surface (Tb.BV/TV) and decreased trabecular plate separation in OVX rats. In contrast, whereas daily PTH injection also increased bone Ca, Mg, and P contents, Tb.BV/TV, Tb.BS/TV, trabecular plate density and thickness, and decreased trabecular plate separation in OVX rats, the combination of boron and PTH had no additional improvement in bone quality over that achieved by PTH alone. In summary, this study shows for the first time that boron enhanced the action of E2, but not that of PTH, to improve trabecular bone quality in OVX rats. 相似文献
245.
1. In relatively low concentrations of NaCl, KCl, and CaCl2 the rate of respiration of Bacillus subtilis remains fairly constant for a period of several hours, while in the higher concentrations, there is a gradual decrease in the rate. 2. NaCl and KCl increase the rate of respiration of Bacillus subtilis somewhat at concentrations of 0.15 M and 0.2 M respectively; in sufficiently high concentrations they decrease the rate. CaCl2 increases the rate of respiration of Bacillus subtilis at a concentration of 0.05 M and decreases the rate at somewhat higher concentrations. 3. The effects of salts upon respiration show a well marked antagonism between NaCl and CaCl2, and between KCl and CaCl2. The antagonism between NaCl and KCl is slight and the antagonism curve shows two maxima. 相似文献
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249.
Matilda Moldenhauer Brooks 《The Journal of general physiology》1921,3(3):337-342
1. Concentrations of La(NO3)3 up to 0.000025 M have little effect upon the rate of respiration of Bacillus subtilis; at 0.000006 M there is an increase in rate, while in higher concentrations there is a decrease in rate. 2. There is well marked antagonism between La(NO3)3 and NaCl, and very slight antagonism between La(NO3)3 and CaCl2. 3. It requires a very small amount of La(NO3)3 to antagonize NaCl, the proportions of the two salts at their maximum antagonism being 99.8 parts of NaCl and 0.2 parts of La(NO3)3. 相似文献
250.
Domenico Sanfelice Hans Koss Tom D. Bunney Gary S. Thompson Brendan Farrell Matilda Katan Alexander L. Breeze 《Biomolecular NMR assignments》2018,12(2):231-235
Fibroblast growth factors receptors (FGFR) are transmembrane protein tyrosine kinases involved in many cellular process, including growth, differentiation and angiogenesis. Dysregulation of FGFR enzymatic activity is associated with developmental disorders and cancers; therefore FGFRs have become attractive targets for drug discovery, with a number of agents in late-stage clinical trials. Here, we present the backbone resonance assignments of FGFR3 tyrosine kinase domain in the ligand-free form and in complex with the canonical FGFR kinase inhibitor PD173074. Analysis of chemical shift changes upon inhibitor binding highlights a characteristic pattern of allosteric network perturbations that is of relevance for future drug discovery activities aimed at development of conformationally-selective FGFR inhibitors. 相似文献