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101.
Avinash A. Kamble Dattatray K. Dalavi Netaji K. Desai Prasad G. Mahajan Govind B. Kolekar Shivajirao R. Patil 《Luminescence》2023,38(11):1883-1891
Sodium dodecyl sulfate (SDS)-capped 1-pyrenecarboxaldehyde nanoparticles (PyalNPs) were prepared using a reprecipitation method in an aqueous medium and exhibited red-shifted aggregation-induced enhanced emission (AIEE). The dynamic light scattering (DLS) examination showed narrower particle size distribution with an average particle size of 41 nm, whereas −34.5 mV zeta potential value indicate the negative surface charge and good stability of nanoparticles (NPs) in an aqueous medium. The AIEE was seen at λmax = 473 nm in a fluorescence spectrum of a PyalNP suspension. In the presence of Cu2+ ions, the fluorescence of PyalNPs quenches very significantly, even in the presence of other metal ions like Ba2+, Ca2+, Cd2+, Co2+, Al3+, Fe2+, Hg2+, Ni2+ and Mg2+. The changes in the fluorescence lifetime of PyalNPs in the presence of Cu2+ ions suggested that the type of quenching was dynamic. The fluorescence quenching data for the NPs suspension fitted well into a typical Stern–Volmer relationship in the concentration range 1.0–25 μg/ml of Cu2+ ions. The estimated value of the correlation coefficient R2 = 0.9877 was close to 1 and showed the linear relationship between quenching data and Cu2+ ion concentration. The limit of detection (LOD) was found to be 0.94 ng/ml and is far below the tolerable intake limit value of 1.3 μg/ml accepted by the World Health Organization for Cu2+ ions in drinking water. The fluorescence quenching approach for a SDS-capped Pyal nanosuspension for copper ion quantification is of high specificity and coexisting ions were found to interfere very negligibly. The developed method was successfully applied for the estimation of copper ions in river water samples. 相似文献
102.
Brett A. Shook Jessica B. Lennington Rebecca L. Acabchuk Meredith Halling Ye Sun John Peters Qian Wu Amit Mahajan Douglas W. Fellows Joanne C. Conover 《Aging cell》2014,13(2):340-350
Age‐associated ventriculomegaly is typically attributed to neurodegeneration; however, additional factors might initiate or contribute to progressive ventricular expansion. By directly linking postmortem human MRI sequences with histological features of periventricular tissue, we show that substantial lateral ventricle surface gliosis is associated with ventriculomegaly. To examine whether loss of ependymal cell coverage resulting in ventricle surface glial scarring can lead directly to ventricle enlargement independent of any other injury or degenerative loss, we modeled in mice the glial scarring found along the lateral ventricle surface in aged humans. Neuraminidase, which cleaves glycosidic linkages of apical adherens junction proteins, was administered intracerebroventricularly to denude areas of ependymal cells. Substantial ependymal cell loss resulted in reactive gliosis rather than stem cell‐mediated regenerative repair of the ventricle lining, and the gliotic regions showed morphologic and phenotypic characteristics similar to those found in aged humans. Increased levels of aquaporin‐4, indicative of edema, observed in regions of periventricular gliosis in human tissue were also replicated in our mouse model. 3D modeling together with volume measurements revealed that mice with ventricle surface scarring developed expanded ventricles, independent of neurodegeneration. Through a comprehensive, comparative analysis of the lateral ventricles and associated periventricular tissue in aged humans and mouse, followed by modeling of surface gliosis in mice, we have demonstrated a direct link between lateral ventricle surface gliosis and ventricle enlargement. These studies highlight the importance of maintaining an intact ependymal cell lining throughout aging. 相似文献
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105.
Roles of the sequence encoding tobacco etch virus capsid protein in genome amplification: requirements for the translation process and a cis-active element. 总被引:6,自引:2,他引:4 下载免费PDF全文
The roles of the capsid protein (CP) and the CP coding sequence of tobacco etch potyvirus (TEV) in genome amplification were analyzed. A series of frameshift-stop codon mutations that interrupted translation of the CP coding sequence at various positions were introduced into the TEV genome. A series of 3' deletion mutants that lacked the CP coding sequence beyond each of the frameshift-stop codon mutations were also produced. In addition, a series of 5' CP deletion mutants were generated. Amplification of genomes containing either frameshift-stop codon insertions after codons 1, 59, 103, and 138 or genomes containing the corresponding 3' deletions of the CP coding sequence was reduced by 100- to 1,000-fold relative to that of the parental genome in inoculated protoplasts. In contrast, a mutant containing a frameshift-stop codon after CP position 189 was amplified to 27% of the level of the parental virus, but the corresponding 3' deletion mutant lacking codons 190 to 261 was nonviable. Deletion mutants lacking CP codons 2 to 100, 2 to 150, 2 to 189, and 2 to 210 were amplified relatively efficiently in protoplasts, but a deletion mutant lacking codons 2 to 230 was nonviable. None of the amplification-defective frameshift-stop codon or deletion mutants was rescued in transgenic cells expressing TEV CP, although the transgenic CP was able to rescue intercellular movement defects of replication-competent CP mutants. Coupled with previous results, these data led to the conclusions that (i) TEV genome amplification requires translation to a position between CP codons 138 and 189 but does not require the CP product and (ii) the TEV CP coding sequence contains a cis-active RNA element between codons 211 and 246. The implications of these findings on mechanisms of RNA replication and genome evolution are discussed. 相似文献
106.
Hieng Chiong Tie Divyanshu Mahajan Bing Chen Li Cheng Antonius M. J. VanDongen Lei Lu 《Molecular biology of the cell》2016,27(5):848-861
Cellular functions of the Golgi are determined by the unique distribution of its resident proteins. Currently, electron microscopy is required for the localization of a Golgi protein at the sub-Golgi level. We developed a quantitative sub-Golgi localization method based on centers of fluorescence masses of nocodazole-induced Golgi ministacks under conventional optical microscopy. Our method is rapid, convenient, and quantitative, and it yields a practical localization resolution of ∼30 nm. The method was validated by the previous electron microscopy data. We quantitatively studied the intra-Golgi trafficking of synchronized secretory membrane cargoes and directly demonstrated the cisternal progression of cargoes from the cis- to the trans-Golgi. Our data suggest that the constitutive efflux of secretory cargoes could be restricted at the Golgi stack, and the entry of the trans-Golgi network in secretory pathway could be signal dependent. 相似文献
107.
In 1949, Fowler (J. Appl. Physiol. 2: 283-299) advocated calculation of a "dilution index" from data of the alveolar plateau of single-breath tests; the calculation provides an estimate of the dilution of resident gas in the lung that gave rise to the observed concentrations. In this communication, we show that the calculation can be applied to conventional single-breath tests where O2 is inhaled by air-breathing persons, and we illustrate the principle with vital capacity breaths of a mixture that contained a low concentration of neon. The dilution was approximately 3:1 in young subjects (20-30 yr), as if a vital capacity of 6 liters were mixed with a residual volume of 2 liters. The dilution was less, 2:1, in older subjects (56 yr) and tended to become as low as 1:1 during emptying of the closing volume. In addition to being more informative, the dilution index format allows common sense comparison of alveolar plateau levels and slopes when single-breath tests are done by various methods. 相似文献
108.
Seven strains of Mycoplasma mycoides subsp. mycoides (LC, Y-Goat) were isolated from 4 of 85 (4.7%) cases of bovine abortion. The biochemical characters of all the isolates were homogenous (except for one sucrose negative isolate), but variation in sensitivity to neomycin, kanamycin and streptomycin were noted. The only gross lesions of internal organs in aborted fetuses were congestion of liver and lungs, and hemorrhagic patches on the heart surface. Significant microscopic lesions were encountered in lungs (edema of the interlobular septae, thickened alveolar wall, lymphocytic infiltration, septal hyperplasia and alveolar infiltration with neutrophils and macrophages), liver (mild lymphocytic infiltration in the hepatic triad, hypertrophy of Von-kupffer cells), kidney (degenerative necrosis and desquamation of tubular epithelium, and the marked lymphocytic infiltration in the interstitium), spleen (depleted lymphoid tissues, infiltration of lymphocytes, macrophage and plasma cells in the red pulp) and heart (lymphocytic myocarditis). The observations of this study focus on the role of M. mycoides subsp. mycoides (LC variant) in bovine abortions. 相似文献
109.
Intact amyloplasts from endosperm of developing wheat grains have been isolated by first preparing the protoplasts and then
fractionating the lysate of the protoplasts on percoll and ficoll gradients, respectively. Amyloplasts isolated as above were
functional and not contaminated by cytosol or by organelles likely to be involved in carbohydrate metabolism. The enzyme distribution
studies indicated that ADP-glucose pyrophosphorylase and starch synthase were confined to amyloplasts, whereas invertase,
sucrose synthase, UDP-glucose pyrophosphorylase, hexokinase, phosphofructokinase-2 and fructose-2,6-P2ase were absent fro the amyloplast and mainly confined to the cytosol. Triose-P isomerase, glyceraldehyde-3-P dehydrogenase,
phosphohexose isomerase, phosphoglucomutase, phosphofructokinase, aldolase, PPi-fructose-6-P-1 phosphotransferase, and fructose-l,6-P2ase, though predominantly cytosolic, were also present in the amyloplast. Based on distribution of enzymes, a probable pathway
for starch biosynthesis in amyloplasts of developing wheat grains has been proposed. 相似文献
110.