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排序方式: 共有545条查询结果,搜索用时 15 毫秒
91.
92.
Muhammad Umer Ramanathan Vaidyanathan Nam-Trung Nguyen Muhammad J.A. Shiddiky 《Biotechnology advances》2018,36(4):1367-1389
Circulating tumor cells (CTCs) and their clusters, also known as circulating tumor microemboli (CTM), have emerged as valuable tool that can provide mechanistic insights into the tumor heterogeneity, clonal evolution, and stochastic events within the metastatic cascade. However, recent investigations have hinted that CTM may not be mere aggregates of tumor cells but cells comprising CTM exhibit distinct phenotypic and molecular characteristics in comparison to single CTCs. Moreover, in many cases CTM demonstrated higher metastatic potential and resistance to apoptosis as compared to their single cell counterparts. Thus, their evaluation and enumeration may provide a new dimension to our understanding of cancer biology and metastatic cancer spread as well as offer novel theranostic biomarkers. Most of the existing technologies for isolation of hematogenous tumor cells largely favor single CTCs, hence there is a need to devise new approaches, or re-configure the existing ones, for specific and efficient CTM isolation. Here we review existing knowledge and insights on CTM biology. Furthermore, a critical commentary on current and emerging trends in CTM enrichment and characterization along with recently developed ex-vivo CTC expansion methodologies is presented with the aim to facilitate researchers to identify further avenues of research and development. 相似文献
93.
V. Mallika K.C. Sivakumar G. Aiswarya 《Journal of biomolecular structure & dynamics》2019,37(1):195-209
Quinolone synthase from Aegle marmelos (AmQNS) is a Rutacean-specific plant type III polyketide synthase that synthesizes quinolone, acridone, and benzalacetone with therapeutic potential. Simple architecture and broad substrate affinity of AmQNS make it as one of the target enzymes to produce novel structural scaffolds. Another unique feature of AmQNS despite its high similarity to acridone forming type III polyketide synthase from Citrus microcarpa is the variation in the product formation. Hence, to explore the characteristic features of AmQNS, an in-depth sequence and structure-based bioinformatics analyses were performed. Our studies indicated that AmQNS and its nearest homologs have evolved by a series of gene duplication events and strong purifying selection pressure constrains them in the evolutionary process. Additionally, some amino acid alterations were identified in the functionally important region(s), which can contribute to the functional divergence of the enzyme. Prediction of favorable amino acid substitutions will be advantageous in the metabolic engineering of AmQNS for the production of novel compounds. Furthermore, comparative modeling and docking studies were utilized to investigate the structural behavior and small molecule interaction pattern of AmQNS. The observations and results reported here are crucial for advancing our understanding of AmQNS’s phylogenetic position, selection pressure, evolvability, interaction pattern and thus providing the foundation for further studies on the structural and reaction mechanism. 相似文献
94.
S G Raju A V Kamath C S Vaidyanathan 《Biochemical and biophysical research communications》1988,154(2):537-543
4-Hydroxyphenylacetic acid 3-hydroxylase is a key enzyme in the pathway for the microbial degradation of phenylalanine, tyrosine and many aromatic amines. This enzyme was purified to homogeneity from Pseudomonas putida by affinity chromatography. The protein had a molecular weight of 91,000 and was a dimer of identical subunits. It was a typical external flavoprotein monooxygenase and showed an absolute requirement of NADH for activity. The enzyme had a pH optimum of 7.5 and the Km values for 4-hydroxyphenylacetic acid and NADH were 2 x 10(-4) M and 5.9 x 10(-5) M respectively. It was strongly inhibited by heavy metal ions and thiol reagents, suggesting the possible involvement of -SH group(s) in enzyme reaction. 相似文献
95.
Trivalent rare‐earth activated hexagonal lanthanum fluoride (LaF3:RE3+, where RE = Tb,Sm, Dy and Tm) nanocrystals: Synthesis and optical properties 下载免费PDF全文
The LaF3 nanocrystals through a facile hydrothermal route with hexagonal structures have been synthesized via doping of trivalent rare earth (RE3+) ions – RE = Tb, Sm, Dy and Tm – with rod‐like and perforated morphologies using NH4F as fluorine precursor. Hexagonal phase formation was confirmed by powder X‐ray diffraction. The crystalline sizes were calculated by the Scherrer equation where found to have an average crystalline size of 12 to 35 nm. The morphological studies of the nanocrystals were carried out by means of transmission electron microscopy (TEM). The LaF3:Tm3+,Sm3+ ions show the characteristic emission of Tb3+ and Tm3+ respectively. In Sm3+‐doped LaF3, three prominent emission peaks at 561, 597 and 641 nm were found, which belong to 4G5/2 → 6H5/2, 4G5/2 → 6H7/2 (magnetic dipole) and 4G5/2 → 6H9/2 (electric dipole) transitions, respectively. The Dy3+ activated LaF3 shows blue and yellow emission and the corresponding CIE color coordinate show white light emission (CCT value 10650 K). 相似文献
96.
97.
Conversion of Dexon (p-Dimethylaminobenzenediazo Sodium Sulfonate) to N,N-Dimethyl-p-Phenylenediamine by Pseudomonas fragi Bk9 下载免费PDF全文
N. G. K. Karanth S. G. Bhat C. S. Vaidyanathan V. N. Vasantharajan 《Applied microbiology》1974,27(1):43-46
The metabolism of the fungicide Dexon (p-dimethylaminobenzenediazo sodium sulfonate) by a soil bacterium is reported for the first time. The organism which is capable of using Dexon only by a co-metabolic process was obtained by enrichment culture and was identified as Pseudomonas fragi. The first metabolic product of Dexon was identified as N,N-dimethyl-p-phenylenediamine. The presence of an enzyme, p-dimethylaminobenzenediazo sodium sulfonate reductase, capable of reducing Dexon to N,N-dimethyl-p-phenylenediamine has been demonstrated in the cell-free extracts of the organism. The enzyme is found to be in the soluble fraction and requires dithiothreitol as a reductant. 相似文献
98.
99.
P. Taiwar S. R. Pal Poonamjit Kaur R. Kaiwar T. Jayashree M. S. Rao S. Vaidyanathan 《Mycopathologia》1986,94(1):39-44
Acetone, carbontetrachloride, ethyl alcohol, mixture of ethyl alcohol and acetone, and heat were assessed for fixative property for direct immunoflurorescent (IF) staining of antibody-coated Candida cells. The results indicated that ethyl alcohol was the most suitable fixative for the test. Antisera containing 16 units of Candida albicans type A agglutinin were found essential to get optimal detectable fluorescence of antibody-coated yeast cells. IF test showed cross reactivity between the yeasts of C. albicans and C. tropicalis. However, there was no cross reactivity with the conidia of A. flavus.The direct IF test could demonstrate antibody-coated yeast cells and pseudomycelia in deposits of urine in the direct smear. It correlated well with microscopy and culture studies. At times, it could demonstrate the antibody-coated yeasts earlier than routine significant culture. It could also differentiate the significant from non-significant fungal isolates from urine. 相似文献
100.
Anthranilic acid hydroxylase from Aspergillus niger 总被引:2,自引:0,他引:2