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1.
BS Sabna Thankappan Bency Mahendran Ramasamy Muthusamy Gayathri Femil selta Daniel Raja Angayarkanni Jayaraman 《Probiotics and antimicrobial proteins》2021,13(4):993-1004
Probiotics and Antimicrobial Proteins - Gamma-aminobutyric acid (GABA) is a principal inhibitory neurotransmitter in the central nervous system and is produced by irreversible decarboxylation of... 相似文献
2.
Anderson O. Lobo Erica F. Antunes Mariana BS Palma Cristina Pacheco‐Soares Vladimir J. Trava‐Airoldi Evaldo J. Corat 《Cell biology international》2010,34(4):393-398
Monolayer formation of SaOS‐2 (human osteoblast‐like cells) was observed on VACNT (vertically aligned multiwalled carbon nanotubes) scaffolds without purification or functionalization. The VACNT were produced by a microwave plasma chemical vapour deposition on titanium surfaces with nickel or iron as catalyst. Cell viability and morphology studies were evaluated by LDH (lactate dehydrogenase) release assay and SEM (scanning electron microscopy), respectively. The non‐toxicity and the flat spreading with monolayer formation of the SaOs‐2 on VACNT scaffolds surface indicate that they can be used for biomedical applications. 相似文献
3.
Madiraju C Edler MC Hamel E Raccor BS Balachandran R Zhu G Giuliano KA Vogt A Shin Y Fournier JH Fukui Y Brückner AM Curran DP Day BW 《Biochemistry》2005,44(45):15053-15063
(-)-Dictyostatin is a sponge-derived, 22-member macrolactone natural product shown to cause cells to accumulate in the G2/M phase of the cell cycle, with changes in intracellular microtubules analogous to those observed with paclitaxel treatment. Dictyostatin also induces assembly of purified tubulin more rapidly than does paclitaxel, and nearly as vigorously as does dictyostatin's close structural congener, (+)-discodermolide (Isbrucker et al. (2003), Biochem. Pharmacol. 65, 75-82). We used synthetic (-)-dictyostatin to study its biochemical and cytological activities in greater detail. The antiproliferative activity of dictyostatin did not differ greatly from that of paclitaxel or discodermolide. Like discodermolide, dictyostatin retained antiproliferative activity against human ovarian carcinoma cells resistant to paclitaxel due to beta-tubulin mutations and caused conversion of cellular soluble tubulin pools to microtubules. Detailed comparison of the abilities of dictyostatin and discodermolide to induce tubulin assembly demonstrated that the compounds had similar potencies. Dictyostatin inhibited the binding of radiolabeled discodermolide to microtubules more potently than any other compound examined, and dictyostatin and discodermolide had equivalent activity as inhibitors of the binding of both radiolabeled epothilone B and paclitaxel to microtubules. These results are consistent with the idea that the macrocyclic structure of dictyostatin represents the template for the bioactive conformation of discodermolide. 相似文献
4.
The immunophenotype of HT29 human colon cancer cells implanted into severe combined immunodeficient mice was assessed in primary
tumours and their metastases in the lungs using an indirect immunohistochemical method. After primary tumours were surgically
removed, the metastases were given time to develop, thus paralleling the clinical situation. While vimentin was negative in
both primary and secondary tumours, E-cadherin was present as membrane-bound labelling in the primary tumours only. Whereas
the markers p53, MIB1, PCNA and CEA were consistently positive in both primary and metastatic tumours, CD44 variant 6 and
CA125 were negative in metastases but positive in the primary tumours. There was a significant increase in the percentage
of cells labelled for p53 in the primary tumours compared with the metastases. For the proliferation markers, there was no
significant difference in labelling between primary tumours and metastases for MIB1. Of the cytokeratins examined, CK 20 gave
the strongest and most consistent reaction in both primary and secondary tumours. The results indicate that, for certain immunohistochemical
markers, results are the same in both primary tumours and metastases. Hence, in these cases, antigens that are expressed on
the primary tumour as well as on the metastases can serve as target molecules for immunologically based forms of treatment
of metastases.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
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6.
Comparisons of the molecular evolutionary process at rbcL and ndhF in the grass family (Poaceae) 总被引:2,自引:1,他引:1
We examine rate heterogeneity among evolutionary lineages of the grass
family at two plasmid loci, ndhF and rbcL, and we introduce a method to
determine whether patterns of rate heterogeneity are correlated between
loci. We show both that rates of synonymous evolution are heterogeneous
among grass lineages and that are heterogeneity is correlated between loci
at synonymous sites. At nonsynonymous sites, the pattern of rate
heterogeneity is not correlated between loci, primarily due to an aberrant
pattern of rate heterogeneity at nonsynonymous sites of rbcL. We compare
patterns of synonymous rate heterogeneity to predictors based on the
generation time effect and the speciation rate hypotheses. Although there
is some evidence for generation time effects, neither generation time
effects nor speciation rates appear to be sufficient to explain patterns of
rate heterogeneity in the grass plastid sequences.
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8.
We used simulated data to investigate a number of properties of maximum-
likelihood (ML) phylogenetic tree estimation for the case of four taxa.
Simulated data were generated under a broad range of conditions, including
wide variation in branch lengths, differences in the ratio of transition
and transversion substitutions, and the absence of presence of
gamma-distributed site-to-site rate variation. Data were analyzed in the ML
framework with two different substitution models, and we compared the
ability of the two models to reconstruct the correct topology. Although
both models were inconsistent for some branch-length combinations in the
presence of site-to-site variation, the models were efficient predictors of
topology under most simulation conditions. We also examined the performance
of the likelihood ratio (LR) test for significant positive interior branch
length. This test was found to be misleading under many simulation
conditions, rejecting too often under some simulation conditions. Under the
null hypothesis of zero length internal branch, LR statistics are assumed
to be asymptotically distributed chi 2(1); with limited data, the
distribution of LR statistics under the null hypothesis varies from chi
2(1).
相似文献
9.
Tian-Yi?Chi George?G?Chen Lok-Kee?Ho Paul?BS?LaiEmail author 《Cancer cell international》2005,5(1):27
p53 is important in the development of hepatocellular carcinoma (HCC) and in therapeutic approaches, but the mechanism whereby
it inhibits HCC growth is still unclear. The aim of the present study was to establish a HCC cell system in which p53 levels
can be regulated. Full-length wild-type p53 cDNA obtained by PCR was cloned into a retroviral response vector controlled by
the tetracycline responsive element (RevTRE-p53). The regulatory vectors RevTet-Off and RevTRE-p53 were transfected into a
packaging cell line, PT67. Hep3B cells in which the p53 gene was deleted were infected with RevTet-Off viral particles from
the PT67. Three G418-resistant cell clones with high luciferase expression and low background were infected with RevTRE-p53.
By screening dozens of RevTRE-p53-infected clones with hygromycin we identified the one with the highest expression of p53
and the lowest background after doxycycline treatment. The results showed that p53 expression in this cell clone could be
simply turned on or off by removing or adding doxycycline. Furthermore, it was found that the level of p53 protein was negatively
and sensitively related to the doxycycline concentration. In conclusion, we have established a HCC cell line in which p53
expression can be switched on or off and regulated in a dose- and time-dependent manner. 相似文献
10.
Likelihood-ratio statistics are proposed to test for heterogeneity in
nucleotide substitution rate among regions of a DNA sequence. The tests
examine three-sequence phylogenies, and two specific tests are proposed: a
test to detect rate heterogeneity among genic regions within a sequence,
over all evolutionary lineages; and a test to detect rate heterogeneity
among regions in a specific evolutionary lineage. Simulations examine the
ability of tests to detect a single region that varies in nucleotide
substitution rate relative to the remainder of the sequence. A 50-bp region
with a fivefold substitution-rate increase can be detected > or = 90% of
the time when it is found in all three lineages of the phylogeny, and a
50-bp region of fivefold rate increase can be detected with approximately
70% power when it is found in only one evolutionary lineage. Simulation
also examines the effect of transition- and transversion-rate differences.
The tests are applied to published DNA sequences. While the tests are
powerful, significant results can be difficult to interpret biologically.
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