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71.
We recently reported that bile salts play a role in the regulation of mucin
secretion by cultured dog gallbladder epithelial cells. In this study we
have examined whether bile salts also influence mucin secretion by the
human epithelial colon cell line LS174T. Solutions of bile salts were
applied to monolayers of LS174T cells. Mucin secretion was quantified by
measuring the secretion of [3H]GlcNAc labeled glycoproteins. Both
unconjugated bile salts as well as taurine conjugated bile salts stimulated
mucin secretion by the colon cells in a dose-dependent fashion. Hydrophobic
bile salts were more potent stimulators than hydrophilic bile salts. Free
(unconjugated) bile salts were more stimulatory compared with their taurine
conjugated counterparts. Stimulation of mucin secretion by LS174T cells was
found to occur at much lower bile salt concentrations than in the
experiments with the dog gallbladder epithelial cells. The protein kinase C
activators PMA and PDB had no stimulatory effect on mucin secretion. We
conclude that mucin secretion by the human colon epithelial cell line
LS174T is regulated by bile salts. We suggest that regulation of mucin
secretion by bile salts might be a common mechanism, by which different
epithelia protect themselves against the detergent action of bile salts, to
which they are exposed throughout the gastrointestinal tract.
相似文献
72.
Ponnulakshmi Rajagopal Selvaraj Jayaraman Shazia Fathima JH Saravanan Radhakrishnan Patil Ashlesh Laxman Vijaya Prakash Krishnan Muthaiah Satyendra Chandra Tripathi TS Gugapriya Aaditya Madhusudan Tarnekar Gayatri Girish Muthiyan Vishwajit Ravindra Deshmukh Bharat Ramrao Sontakke Kirubhanand Chandrashekar 《Bioinformation》2021,17(11):928
73.
Chella Perumal Palanisamy Shazia Fathima JH Ramya Sekar Ponnulakshmi Rajagopal Selvaraj Jeyaraman 《Bioinformation》2021,17(7):705
It is of interest to document the inhibition of A2780 cell proliferation using Mollugo nudicaulis Lam.(M.nudicaulis) extract by MTT assay and by monitoring the CXCR4 and HER2 expression through RT-PCR analysis. Results shown that the n-hexane extract of M.nudicaulis have anticancer activity IC50 values of 32.46±0.92 µg/mL on A2780 cell lines. It is further found that the CXCR4 and HER2 mRNA and protein expression were significantly reduced in M.nudicaulis treated A2780 cell lines. Thus, the n-hexane extract of M.nudicaulis is a natural source of bioactive compounds as potential anticancer agents. 相似文献
74.
The investigation was carried out at one station in Korsfjorden,a typical deep silled fjord of western Norway. During 14 cruisesfrom 4 February to 30 June 1977 ATP, chlorophll a, phaeopigmenta, and in situ 14C-assimilation were measured in the net (>30µm), nano and ultraplankton (<5 µm). Sampleswere collected from five light depths within euphotic zone.The impact of hydrographical conditions and light regime onthe bloom dynamics was also studied. In the periods 4 February-7 March and 13 April-30 June, ultraplankton contributed >60%to the total primary production while net and nanoplankton dominatedfrom 7 March to 13 April. The diatoms Skeletonema costatum,Chaetoceros compressits and C. debilis, and Rhizosolenia hebetatavar. semispina made up the main part of the biomass on 21 March,28 March and 4 April respectively. A shade adapted diatom societywas located at the top of the nutricline in late June with S.costatum, Chaetoceros spp., and Thalassiosira spp. as the dominantspecies. The highest assimilation number of eight for the netplankton and four for the ultraplankton were found at the depthof 32% light intensity on 28 March and 24 May respectively.Linear relationships were found between chlorophyll a and ATPfor the different size fractions with regression slopes rangingfrom 4.3 to 5.8. The total primary production for the periodof investigation was calculated to 74 g C m2. Light regimeand water column stability were decisive factors for the outburstof the first diatom bloom in late March. Grazing on net planktondiatoms increased during late March-early April. Changes inthe longshore wind-stress component were found to be essentialfor the understanding of the bloom dynamics. 相似文献
75.
Proliferation of three murine marrow-derived stromal cell lines, LC1, LC2, and LC3, depended on initial cell density. For LC2 and LC3, the cell density-dependence was negated by conditioned-media, indicating growth dependence on a soluble growth factor. For LC1, conditioned-media failed to stimulate proliferation, suggesting growth dependence on direct cell-cell contact. 相似文献
76.
Choline acetyltransferase activity of spinal cord cell cultures increased by co-culture with muscle and by muscle-conditioned medium 总被引:9,自引:3,他引:6
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Activity of the enzyme choline acetyltransferase (CAT), which mediates the synthesis of the neurotransmitter, acetylcholine, was increased up to 20- fold in spinal cord (SC) cells grown in culture with muscle cells for 2 wk. This increase was directly related to the duration of co-culture as well as to the cell density of both the SC and muscle involved and was not affected by the presence of the acetylcholine receptor blocking agent, α-bungarotoxin. Glutamic acid decarboxylase (GAD) activity was often markedly decreased in SC-muscle cultures while the activities of acetylcholinesterase and several other enzymes were little changed. Increased CAT activity was also observed when SC cultures were maintained in medium which had been conditioned by muscle cells or by undifferentiated cells from embryonic muscle. Muscle-conditioned medium (CM) did not affect the activities of SC cell GAD or acetylcholinesterase. Dilution or concentration of the CM directly affected its ability to increase SC CAT activity , as did the duration and timing of exposure of the SC cells to the CM. The medium could be conditioned by muscle cells in the presence or absence of serum, and remained effective after dialysis or heating to 58 degrees C. Membrane filtration data were consistent with the conclusion that the active material(s) in CM had a molecular weight in excess of 50,000 daltons. We conclude that large molecular weight material that is released by muscle cells is capable of producing a specific increase in CAT activity of SC cells. 相似文献
77.
78.
Stable expression of mammalian beta 1,4-galactosyltransferase extends the N-glycosylation pathway in insect cells 总被引:5,自引:2,他引:3
An established lepidopteran insect cell line (Sf9) was cotransfected with
expression plasmids encoding neomycin phosphotransferase and bovine beta
1,4-galactosyltransferase. Neomycin-resistant transformants were selected,
assayed for beta 1,4-galactosyltransferase activity, and the transformant
with the highest level of enzymatic activity was characterized. Southern
blots indicated that this transformed Sf9 cell derivative contained
multiple copies of the galactosyltransferase- encoding expression plasmid
integrated at a single site in its genome. One-step growth curves showed
that these cells supported normal levels of baculovirus replication.
Baculovirus infection of the transformed cells stimulated beta
1,4-galactosyltransferase activity almost 5-fold by 12 h postinfection.
This was followed by a gradual decline in activity, but the infected cells
still had about as much activity as uninfected controls as late as 48 h
after infection and they were able to produce a beta 1,4-galactosylated
virion glycoprotein during infection. Infection of the transformed cells
with a conventional recombinant baculovirus expression vector encoding
human tissue plasminogen activator also resulted in the production of a
galactosylated end-product. These results demonstrate that stable
transformation can be used to add a functional mammalian
glycosyltransferase to lepidopteran insect cells and extend their N-
glycosylation pathway. Furthermore, stably-transformed insect cells can be
used as modified hosts for conventional baculovirus expression vectors to
produce foreign glycoproteins with "mammalianized" glycans which more
closely resemble those produced by higher eucaryotes.
相似文献
79.
JH Curtis 《BMJ (Clinical research ed.)》1998,317(7162):856-857
80.