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71.
Evaluation of bladder wall mechanical behavior is important in understanding the functional changes that occur in response to pathologic processes such as partial bladder outlet obstruction (pBOO). In the murine model, the traditional approach of cystometry to describe bladder compliance can prove difficult secondary to small bladder capacity and surgical exposure of the bladder. Here, we explore an alternative technique to characterize murine mechanical properties by applying biaxial mechanical stretch to murine bladders that had undergone pBOO. 5–6 week old female C57/Bl6 mice were ovariectomized and subjected to pBOO via an open surgical urethral ligation and sacrificed after 4 weeks (n=12). Age matched controls (n=6) were also analyzed. Bladders were separated based on phenotype of fibrotic (n=6) or distended (n=6) at the time of harvest. Biaxial testing was performed in modified Kreb's solution at 37 °C. Tissue was preconditioned to 10 cycles and mechanical response was evaluated by comparing axial strain at 50 kPa. The normal murine bladders exhibited anisotropy and were stiffer in the longitudinal direction. All mice showed a loss of anisotropy after 4 weeks of pBOO. The two phenotypes observed after pBOO, fibrotic and distended, exhibited less and more extensibility, respectively. These proof-of-principle data demonstrate that pBOO creates quantifiable changes in the mechanics of the murine bladder that can be effectively quantified with biaxial testing. 相似文献
72.
Hiroshi Sato Toshio Nagai Dhandapani Kuppuswamy Takahiro Narishige Masaaki Koide Donald R. Menick George Cooper IV 《The Journal of cell biology》1997,139(4):963-973
Increased microtubule density, for which microtubule stabilization is one potential mechanism, causes contractile dysfunction in cardiac hypertrophy. After microtubule assembly, α-tubulin undergoes two, likely sequential, time-dependent posttranslational changes: reversible carboxy-terminal detyrosination (Tyr-tubulin ↔ Glu-tubulin) and then irreversible deglutamination (Glu-tubulin → Δ2-tubulin), such that Glu- and Δ2-tubulin are markers for long-lived, stable microtubules. Therefore, we generated antibodies for Tyr-, Glu-, and Δ2-tubulin and used them for staining of right and left ventricular cardiocytes from control cats and cats with right ventricular hypertrophy. Tyr- tubulin microtubule staining was equal in right and left ventricular cardiocytes of control cats, but Glu-tubulin and Δ2-tubulin staining were insignificant, i.e., the microtubules were labile. However, Glu- and Δ2-tubulin were conspicuous in microtubules of right ventricular cardiocytes from pressure overloaded cats, i.e., the microtubules were stable. This finding was confirmed in terms of increased microtubule drug and cold stability in the hypertrophied cells. In further studies, we found an increase in a microtubule binding protein, microtubule-associated protein 4, on both mRNA and protein levels in pressure-hypertrophied myocardium. Thus, microtubule stabilization, likely facilitated by binding of a microtubule-associated protein, may be a mechanism for the increased microtubule density characteristic of pressure overload cardiac hypertrophy. 相似文献
73.
Consumers want meat products that are healthful and affordable. However, consumers will repurchase a product only if it tastes good. Consumers identified reasons for purchasing frankfurters and evaluated overall acceptability of 10 commercially available frankfurters. Consumers listed “taste” as the most important factor when purchasing frankfurters; only 16% of the consumers indicated that nutrition/health was the most important criterion. Nineteen consumer-perceived sensory and liking attributes were measured for the frankfurters in this study. The intensities of the attributes ranged from low to moderately high. All the frankfurters scored in the low to moderate range for overall acceptability. Most of the scores for liking of individual attributes correlated highly with overall liking, indicating that many of the questions relating to attribute liking could be eliminated. 相似文献
74.
Spa47 is an oligomerization‐activated type three secretion system (T3SS) ATPase from Shigella flexneri 下载免费PDF全文
Jamie L. Burgess Heather B. Jones Prashant Kumar Ronald T. Toth IV C. Russell Middaugh Edwin Antony Nicholas E. Dickenson 《Protein science : a publication of the Protein Society》2016,25(5):1037-1048
Gram‐negative pathogens often use conserved type three secretion systems (T3SS) for virulence. The Shigella type three secretion apparatus (T3SA) penetrates the host cell membrane and provides a unidirectional conduit for injection of effectors into host cells. The protein Spa47 localizes to the base of the apparatus and is speculated to be an ATPase that provides the energy for T3SA formation and secretion. Here, we developed an expression and purification protocol, producing active Spa47 and providing the first direct evidence that Spa47 is a bona fide ATPase. Additionally, size exclusion chromatography and analytical ultracentrifugation identified multiple oligomeric species of Spa47 with the largest greater than 8 fold more active for ATP hydrolysis than the monomer. An ATPase inactive Spa47 point mutant was then engineered by targeting a conserved Lysine within the predicted Walker A motif of Spa47. Interestingly, the mutant maintained a similar oligomerization pattern as active Spa47, but was unable to restore invasion phenotype when used to complement a spa47 null S. flexneri strain. Together, these results identify Spa47 as a Shigella T3SS ATPase and suggest that its activity is linked to oligomerization, perhaps as a regulatory mechanism as seen in some related pathogens. Additionally, Spa47 catalyzed ATP hydrolysis appears to be essential for host cell invasion, providing a strong platform for additional studies dissecting its role in virulence and providing an attractive target for anti‐infective agents. 相似文献
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77.
Vertical polyacrylamide gel electrophoresis was used to separate enzyme proteins at 73 putative loci in natural house fly
populations sampled in central Iowa. Thirty-nine of the loci were polymorphic (53%). The mean effective number of alleles
per polymorphic locus was 1.93 and 1.47 alleles among 68 scored loci. Observed and expected heterozygosities at 34 house fly
loci were 0.1628 and 0.1834, respectively. No statistically significant differentiation was detected among nine central Iowa
fly populations in 1989 or among nine Iowa and three Minnesota populations in 1990.
Journal Paper No. J-14125 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project No. 2949. 相似文献
78.
Henry Hoppe IV Katherine M. Call Phaik-Mooi Leong William G. Thilly 《Mutation research》1991,250(1-2):411-421
Cell of the human lymphoblast line WI-L2 and its derivative TK-6 were synchronized by centrifugal elutriation and cell-cycle dependent mutation to 6TGR (HPRT) and OUAR (Na+, K+ ATPase) measured. Bromodeoxyuridine induced 6TGR and OUAR mutations within S phase while butylmethylsulfonate induced mutation displayed no cell-cycle dependence. The data indicate that centrifugal elutriation is a facile means to obtain a useful degree of synchrony for these cell lines. 相似文献
79.
Richard W. Joy IV Edward C. Yeung Lisheng Kong Trevor A. Thorpe 《In vitro cellular & developmental biology. Plant》1991,27(1):32-41
Summary The growth and development of white spruce somatic embryos was followed from the filamentous immature to the mature cotyledonary
embryo stage. Histochemical examination of the various stages of embryo development showed that lipids, proteins, and polysaccharides
were produced to varying degrees during the process. During early stages (1 to 2 wk on ABA), mostly polysaccharide was produced,
whereas during later stages, polysaccharides, lipids, and protein accumulated. Electron microscopy indicated that lipid deposition
in somatic embryos started during the first week after transfer to ABA-containing medium. Deposition of the storage products
began at the basal end of the embryonal mass and within the proximal zone of the suspensors. Accumulation continued to the
peripheral regions and then inward toward the cortex of the developing embryo. In all cases, polysaccharide accumulated first,
followed by lipid and lastly, protein. Quantitatively, cotyledonary stage somatic embryos had less lipid and protein and more
starch when compared to zygotic embryos at the same developmental stage. Total protein profiles elucidated by sodium dodecyl
sulfate-polyacrylamide gel electrophoresis indicated that the majority of proteins were similar in zygotic and somatic embryos.
Prominent protein bands were found at 30, 20, 19.5, 15, 14.4, 12, and 10 Kd. However, protein bands at 40, 15, and 12 Kd in
total protein from somatic embryos were either absent or highly underexpressed. 相似文献
80.