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151.
The effect of tea polyphenol (TP) on cognitive and anti-cholinesterase activity was examined in scopolamine-treated mice. Chronic administration of TP significantly reversed scopolamine-induced retention deficits in both step-through passive avoidance and spontaneous alternation behavior tasks. Furthermore, TP exhibited a dramatic inhibitory effect on acetylcholinesterase activity. This finding suggests that TP might be useful in the treatment of Alzheimer's disease. 相似文献
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153.
Cercaria yamagutii Ito, 1957, was found in the marine mesogastropods Lunatia fortuni and Glossaulax didyma from the tidelands of Simpo located at the estuary of the Mankyoung River, which runs to the western coast of Korea. Metacercariae were found in a marine bivalve Mactra veneriformis after being infected with C. yamagutii experimentally. When a sea gull, Larus crassiostris, was fed with the metacercariae collected from the infected M. veneriformis, adult worms were recovered 10 days later. It was confirmed that the parasites collected from L. crassiostris were Acanthoparyphium tyosenense Yamaguti, 1939. From the results of this life cycle study, it was determined that the first intermediate hosts of A. tyosenense are L. fortuni and G. didyma. The second intermediate and final hosts are M. veneriformis and L. crassiostris, respectively. Mactra veneriformis was experimentally infected with C. yamagutii isolated from L. fortuni and G. didyma by maintaining them in a water tank for 30 min at about 20 C. The cercariae entered M. veneriformis through their incurrent siphons. Five hours after infection, the cercariae tails began to separate from the bodies, and the cercariae formed cysts. Mature cysts were formed 340 hr (14 days) after infection and identified as the metacercariae of A. tyosenense. The prevalence of A. tyosenense metacercariae was 99.5% in naturally infected M. veneriformis. This is the first report of C. yamagutii as the cercaria of A. tyosenense, and the complete life cycle of A. tyosenense was established in Korea. 相似文献
154.
Thomas F. Holzman Christine C. Chung Rohinton Edalji David A. Egan Margaret Martin Earl J. Gubbins Grant A. Krafft Gary T. Wang A. Mitchel Thomas Saul H. Rosenberg et al. 《Journal of Protein Chemistry》1991,10(5):553-563
The kinetic behavior andpH-stability of recombinant human renin was analyzed using a new fluorogenic substrate based on the normal P6-P3 renin cleavage sequence in human angiotensinogen. The design of this fluorogenic substrate makes possible, for the first time, direct monitoring of the kinetics of proteolytic conversion of prorenin to renin. ThepH-stability profile for renin, measured with the substrate at 25°C, indicated a broad plateau of stability betweenpH 6.0 and 10.0. Analysis of thepH-activity profile of renin for the substrate indicated a minimumK
m
(1.8 µM) atpH 7.4 and a maximumV
m
betweenpH 7.4 and 8.0. The thermodynamics of the binding of a novel, soluble, peptidomimetic inhibitor to renin indicated it is possible to retain the tight-binding characteristics and enthalpy contributions to binding of larger peptide-derived inhibitors, while reducing inhibitor size and entropic contributions to binding. A novel derivative of the fluorogenic substrate, containing a 3-methyl histidine substitution at the P2 site, was used to test the recent hypothesis that renin functions by virtue of substrate-directed catalysis. 相似文献
155.
Wang Shih-Wei Chung Chih-Ling Yu-Chen Kao René Martin Hans-Joachim Knölker Meng-Shin Shiao 《Journal of enzyme inhibition and medicinal chemistry》2018,33(1):920-935
Pentabromopseudilin (PBrP) is a marine antibiotic isolated from the marine bacteria Pseudomonas bromoutilis and Alteromonas luteoviolaceus. PBrP exhibits antimicrobial, anti-tumour, and phytotoxic activities. In mammalian cells, PBrP is known to act as a reversible and allosteric inhibitor of myosin Va (MyoVa). In this study, we report that PBrP is a potent inhibitor of transforming growth factor-β (TGF-β) activity. PBrP inhibits TGF-β-stimulated Smad2/3 phosphorylation, plasminogen activator inhibitor-1 (PAI-1) protein production and blocks TGF-β-induced epithelial–mesenchymal transition in epithelial cells. PBrP inhibits TGF-β signalling by reducing the cell-surface expression of type II TGF-β receptor (TβRII) and promotes receptor degradation. Gene silencing approaches suggest that MyoVa plays a crucial role in PBrP-induced TβRII turnover and the subsequent reduction of TGF-β signalling. Because, TGF-β signalling is crucial in the regulation of diverse pathophysiological processes such as tissue fibrosis and cancer development, PBrP should be further explored for its therapeutic role in treating fibrotic diseases and cancer. 相似文献
156.
You stay,but I Hop: Host shifting near and far co‐dominated the evolution of Enchenopa treehoppers 下载免费PDF全文
Yu‐Hsun Hsu Reginald B. Cocroft Robert L. Snyder Chung‐Ping Lin 《Ecology and evolution》2018,8(4):1954-1965
The importance and prevalence of phylogenetic tracking between hosts and dependent organisms caused by co‐evolution and shifting between closely related host species have been debated for decades. Most studies of phylogenetic tracking among phytophagous insects and their host plants have been limited to insects feeding on a narrow range of host species. However, narrow host ranges can confound phylogenetic tracking (phylogenetic tracking hypothesis) with host shifting between hosts of intermediate relationship (intermediate hypothesis). Here, we investigated the evolutionary history of the Enchenopa binotata complex of treehoppers. Each species in this complex has high host fidelity, but the entire complex uses hosts across eight plant orders. The phylogenies of E. binotata were reconstructed to evaluate whether (1) tracking host phylogeny; or (2) shifting between intermediately related host plants better explains the evolutionary history of E. binotata. Our results suggest that E. binotata primarily shifted between both distant and intermediate host plants regardless of host phylogeny and less frequently tracked the phylogeny of their hosts. These findings indicate that phytophagous insects with high host fidelity, such as E. binotata, are capable of adaptation not only to closely related host plants but also to novel hosts, likely with diverse phenology and defense mechanisms. 相似文献
157.
High cell density induces spontaneous bifurcations of dissolved oxygen controllers during CHO cell fermentations 总被引:1,自引:0,他引:1
High cell density cultures of CHO cells growing in a bioreactor under dissolved oxygen control were found to undergo spontaneous bifurcations and a subsequent loss of stability some time into the fermentation. This loss of stability was manifested by sustained and amplified oscillations in the bioreactor dissolved oxygen concentration and in the oxygen gas flow rate to the reactor. To identify potential biological and operational causes for the phenomenon, linear stability analysis was applied in a neighborhood of the experimentally observed bifurcation point. The analysis revealed that two steady state process gains, K(P1) and K(P2), regulated k(l)a and gas phase oxygen concentration inputs, respectively, and the magnitude of K(P1) was found to determine system stability about the bifurcation point. The magnitude of K(P1), and hence the corresponding open-loop steady state gain K(OL1), scaled linearly with the bioreactor cell density, increasing with increasing cell density. These results allowed the generation of a fermentation stability diagram, which partitioned K(C)-N operating space into stable and unstable regions separated by the loci of predicted critically stable controller constants, K(C,critical), as a function of bioreactor cell density. This consistency of this operating diagram with experimentally observed changes in system stability was demonstrated. We conclude that time-dependent increases in cell density are the cause of the observed instabilities and that cell density is the critical bifurcation parameter. The results of this study should be readily applicable to the design of a more robust controller. 相似文献
158.
Park HJ Choi JS Chun MH Chung JW Jeon MH Lee JH Lee MY 《Cell and tissue research》2003,314(2):207-214
We studied the distribution of Bis (Bcl-2 interacting death suppressor) protein in the adult rat brain and spinal cord using immunohistochemistry. Immunoreactivity was observed in specific neuronal populations in distinct nuclei. The most intensely labeled cells were associated with the motor system, including most cranial nerve motor nuclei, Purkinje cells of the cerebellum, the red nucleus, and the ventral motor neurons of the spinal cord. Bis protein was also expressed in several structures associated with the ventricular system, including the subventricular zone of the lateral ventricle and its rostral extension, in the subcommissural organ, and in tanycytes, radial glial cells in the hypothalamus. Using double-labeling techniques, Bis-immunoreactive cells in the rostral migratory stream, coexpressing Bcl-2, were confirmed as glial fibrillary acidic protein-positive astrocytes comprising the glial tubes. The widespread distribution of Bis suggests that this protein has broader functions in the adult rat central nervous system than previously thought, and that it could be associated with a particular role in the rostral migratory system.J.-H. Lee and M.-Y. Lee contributed equally to this study. This work was supported by the KOSEF through the Cell Death Disease Research Center of MRC at the Catholic University of Korea (R13-2002-005-01001-0) and the Catholic Medical Center Research Foundation grant made in the program year of 2002 相似文献
159.
160.
Characterization of a caveolin‐1 mutation associated with both pulmonary arterial hypertension and congenital generalized lipodystrophy 下载免费PDF全文
Bing Han Courtney A. Copeland Yumeko Kawano Erika Berman Rosenzweig Eric D. Austin Layla Shahmirzadi Sha Tang Krishnan Raghunathan Wendy K. Chung Anne K. Kenworthy 《Traffic (Copenhagen, Denmark)》2016,17(12):1297-1312
Congenital generalized lipodystrophy (CGL) and pulmonary arterial hypertension (PAH) have recently been associated with mutations in the caveolin‐1 ( CAV1 ) gene, which encodes the primary structural protein of caveolae. However, little is currently known about how these CAV1 mutations impact caveolae formation or contribute to the development of disease. Here, we identify a heterozygous F160X CAV1 mutation predicted to generate a C‐terminally truncated mutant protein in a patient with both PAH and CGL using whole exome sequencing, and characterize the properties of CAV1 , caveolae‐associated proteins and caveolae in skin fibroblasts isolated from the patient. We show that morphologically defined caveolae are present in patient fibroblasts and that they function in mechanoprotection. However, they exhibited several notable defects, including enhanced accessibility of the C‐terminus of wild‐type CAV1 in caveolae, reduced colocalization of cavin‐1 with CAV1 and decreased stability of both 8S and 70S oligomeric CAV1 complexes that are necessary for caveolae formation. These results were verified independently in reconstituted CAV1 ?/? mouse embryonic fibroblasts. These findings identify defects in caveolae that may serve as contributing factors to the development of PAH and CGL and broaden our knowledge of CAV1 mutations associated with human disease. 相似文献