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1.
The simultaneous determination of the cell cycle phase of individual adherent mesenchymal stem cells (MSCs) using a fluorescence
microscope after staining with 4′,6-diamidine-2′-phenylindole dihydrochloride and bromodeoxyuridine and the laser phase shift
by phase-shifting laser microscopy (PLM) revealed that the laser phase shift of cells in the G2/M phase was markedly higher than that of cells in the G0/G1 phase. Even in the synchronous cultures to G0/G1 and G2/M cell cycle phases, the laser phase shift of the cells in the G2/M phase was markedly higher than that of the cells in the G0/G1 phase. The analysis of the cultures of MSCs from different donors with the addition of FGF2 at different concentrations revealed
that there was a marked negative correlation between the average phase shift and mean generation time. In conclusion, it is
possible to estimate noninvasively the proliferation activity of MSCs population by measuring the phase shift using PLM. 相似文献
2.
Summary Addition of N6,O2′-Dibutyryladenosine cyclic 3′,5′ monophosphate (DB cyclic AMP) plus theophylline or transfer to medium containing 0.2% serum
slowed the growth of cultured mouse mastocytoma cells and eventually arrested their growth in G1 phase. Examination of the
properties of cells arrested by either procedure suggested that the drugs arrested cells in G1 phase 1.5–2 h after the point
of low serum arrest. Cycloheximide prevented the recovery of cell growth after low serum or drug-induced arrest demonstrating
that protein synthesis was necessary to pass either growth restriction point. Cordycepin also prevented drug-arrested cells
from progressing into cycle indicating a requirement for RNA synthesis to overcome the drug-induced growth arrest. Evidence
is also presented that DB cyclic AMP prevented the cells receiving a pulse of calcium necessary to proceed past the DB cyclic
AMP-sensitive growth restriction point. It is suggested that high cyclic AMP levels prevent mastocytoma cells from receiving
a surge of calcium in G1 phase that is necessary if the cells are to proceed to S phase and eventually divide. 相似文献
3.
N.-J. L. Liu Deborah E. Isaksen C. M. Smith D. A. Weisblat 《Development genes and evolution》1998,208(3):117-127
At the four-cell stage, embryos of glossiphoniid leeches comprise identified blastomeres A, B, C and D. Subsequent cleavages
of the A, B and C quadrants yield three large, yolk-rich endodermal precursor cells, macromeres A′′′, B′′′ and C′′′. Eventually,
these cells generate the epithelial lining of the gut via cellularization of a multinucleate syncytium. Meanwhile, cleavage
in the D quadrant generates ten teloblasts that give rise to segmental mesoderm and ectoderm via stem cell divisions. Here
we show that, during cleavage, macromeres A′′′, B′′′ and C′′′ shift clockwise relative to the D quadrant, while C′′′ comes
to envelop the nascent teloblasts. During gastrulation, derivatives of the teloblasts undergo epibolic movements over the
surface of the A′′′, B′′′ and C′′′ macromeres to form the germinal plate, from which segmental tissues arise. We find that
the three macromeres fuse in a stepwise manner to initiate formation of the multinucleate syncytium; cell C′′′ fuses about
25 h after the fusion of A′′′ and B′′′, and the teloblasts fuse with the macromere-derived syncytium later still. When macromeres
are biochemically arrested by microinjecting them with the A chain of ricin, a further difference among the macromeres is
revealed. Biochemical arrest of A′′′ or B′′′ slightly retards the rate of germinal plate formation, but arrest of C′′′ frequently
accelerates this process.
Received: 14 October 1997 / Accepted: 4 February 1998 相似文献
4.
Hsiao YC Hsieh YS Kuo WH Chiou HL Yang SF Chiang WL Chu SC 《Journal of biomedical science》2007,14(1):107-119
Summary Natural products, including flavonoids, are suggested to be involved in the protective effects of fruits and vegetables against
cancer. However, studies concerning the effect of flavonoids frequently lacked data regarding to flavanones. In this study,
we investigated the inhibitory effect of flavanone compounds, including flavanone, 2′-OH flavanone, 4′-OH flavanone, 6-OH
flavanone, naringin and naringenin, on cell growth of various cancer cells. We determined that flavanone and 2′-OH flavanone
inhibited cell growth of A549, LLC, AGS, SK-Hepl and HA22T cancer cells, while other flavanones showed little or no inhibition.
We evaluated growth-inhibitory activity of flavanone and 2′-OH flavanone against highly proliferative human lung cancer cells
(A549) via anchorage-independent and -dependent colony formation assay, and further showed that treatment of flavanone resulted
in a G1 cell cycle arrest with reduction of cyclin D, E and cyclin-dependent kinase (CDK) 2, while treatment of 2′-OH flavanone
led to a G2/M phase accumulation with reduction of cyclin B, D and Cdc2. Moreover, we demonstrated the improvement effect
of flavanone and 2′-OH flavanone with anti-cancer drug, doxorubicin, on A549 cells. Finally, flavanone and 2′-OH flavanone
were evidenced by its inhibition on the growth of A549 and Lewis lung carcinoma cells in vivo.
Yung-Chin Hsiao and Yih-Shou Hsieh are equally contributed to this work. 相似文献
5.
6.
7.
A Chinese Hamster Ovary cell line, CHO1-15500, producing recombinant human tissue type plasminogen activator (tPA) via the dihydrofolate reductase (DHFR) amplification
system, was studied in batch culture. In this system both DHFR and tPA are under the control of the strong constitutive viral
SV40 early promoter. Employing the cumulative viable cell-hour approach, the specific productivity of tPA had maxima in the
lag (0.065 pg cell−1 h−1) and early decline (0.040 pg cell−1 h−1) population growth phases. The viable population was assigned into four subpopulations (G1, S, G2/M phase, and Apoptotic
cells) using flow cytometric analysis. As expected, intracellular DHFR was maximally expressed during the S cell cycle phase.
The production of tPA, however, was found to be a direct linear function of the G1 phase, with a subpopulation specific productivity
of 0.080 pg c-h−1. Productivity maxima in the lag and early decline corroborate the flow cytometric data, indicative that this recombinant
tPA production occurs primarily in the G1 cell cycle phase, not the S phase. This suggests that endogenous regulatory mechanisms
are important controlling influences on the production of recombinant tPA in this ovarian cell line. Productivity from recombinant
cell lines cannot be inferred from either the plasmid construct or the host cell alone. Elucidation of the relationship between
expression of recombinant protein and the cell cycle phases of the host cell is a major component of the characterization
of the animal cell production system. This information facilitates rational process design, including operating mode, modelling
and control, and medium formulation. 相似文献
8.
Yunxue Zhao Guotao Yang Dongmei Ren Xiumei Zhang Qiuwei Yin Xuefei Sun 《Molecular biology reports》2011,38(2):1115-1119
Luteolin, 3′,4′,5,7-tetrahydroxyflavone, has been shown to possess antioxidant, anti-inflammation and anti-cancer properties.
However, its role in lung cancer remains poorly understood. Here we examined the anti-tumorigenic role of luteolin in a commonly
used lung cancer cell line. Luteolin inhibited the growth of A549 cells by inducing G1 phase cell cycle arrest and apoptosis.
Furthermore, stress fiber assembly and cell migration in A549 cells was markedly suppressed by luteolin. 相似文献
9.
N. Schmitz 《Molecular & general genetics : MGG》1999,261(4-5):716-724
The protein kinase p34cdc2 is required at the onset of DNA replication and for entry into mitosis. The catalytic subunit and its regulatory proteins,
notably the cyclins, are conserved from yeast to man. This suggests that the control mechanisms necessary for progression
through the cell cycle in fission yeast are conserved throughout evolution. This work describes the characterization of a
fission yeast strain that is dependent for cell cycle progression on the activity of the p34CDC2 protein kinase from chicken. The response of the chicken p34CDC2 protein kinase to cell cycle components of fission yeast was examined. Cells expressing the chicken p34CDC2 protein divide at reduced size at 31° C. Cells are temperature sensitive at 35.5° C and die as a result of mitotic catastrophe.
This phenotype can be rescued by delaying cell cycle progression at the G1-S transition by adding low concentrations of hydroxyurea.
Schizosaccharomyces pombe cells that are dependent on chicken p34CDC2 are cold sensitive. At 19° C to 25° C cells arrest in the G1 phase, while traversal of the G2-M transition is not blocked
at low temperature. Expression of chicken p34CDC2 in the cold-sensitive G2-M mutant cdc2A21 suppresses the G1 arrest.
Received: 14 October 1998 / Accepted: 15 March 1999 相似文献
10.
Rappolt M Pabst G Rapp G Kriechbaum M Amenitsch H Krenn C Bernstorff S Laggner P 《European biophysics journal : EBJ》2000,29(2):125-133
Experimental evidence supporting the hypothesis of gel-liquid crystalline phase coexistence in the stable ripple phase of
diacylphosphatidylcholines has been obtained from time-resolved X-ray small- (SAXS) and wide-angle diffraction (WAXS) in the
millisecond to second time domain. The pretransition of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) exhibits a thin lamellar liquid crystalline intermediate phase (designated Lα*) if driven far away from equilibrium by an infrared temperature jump (T-jump) technique. The findings can be described by
a two-step model. (1) Instantaneously with the T-jump, an anomalously thin lamellar liquid crystalline intermediate phase
(d = 5.6–5.8 nm) forms, coexisting with the original gel-phase Lβ′. Within the first seconds, the lamellar repeat distance of the intermediate increases to a value of about 6.7 nm. A closer
examination of these kinetics reveals two relaxation components: a fast process, proceeding within tenths of a second, and
a slow process, on the time scale of a few seconds. (2) Finally, both the liquid crystalline and the gel-phase relax into
the stable ripple phase Pβ′. The total process time of the transition is nearly independent of the addition of NaCl, but varies strongly with the chain
length of the lecithin species.
Received: 24 November 1999 / Revised version: 25 February 2000 / Accepted: 25 February 2000 相似文献
11.
The expression of some Saccharomyces cerevisiae genes is induced as cells enter stationary phase. Their mRNAs are translated during a period in the growth cycle when the
translational apparatus is relatively inert, thereby raising the possibility that these mRNAs compete effectively for a limiting
pool of translation factors. To test this idea, the translation of mRNAs carrying different 5′-leaders was compared during
exponential growth and after entry into stationary phase upon glucose starvation. Closely related sets of lacZ mRNAs, carrying 5′-leaders from the PYK1, PGK1, RpL3, Rp29, HSP12, HSP26 or THI4 mRNAs, were studied. These mRNAs displayed differing translational efficiencies during exponential growth, but their relative
translatabilities were not significantly affected by entry into stationary phase, indicating that they compete just as effectively
under these conditions. Polysome analysis revealed that the wild-type PYK1, ACT1 and HSP26 mRNAs are all translated efficiently during stationary phase, when the translational apparatus is relatively inert. Also,
significant levels of the translation initiation factors eIF-2α, eIF-4E and eIF-4A were maintained during the growth cycle.
These data are consistent with the idea that, while translational activity decreases dramatically during entry into stationary
phase, yeast cells maintain excess translational capacity under these conditions.
Received: 31 March 1998 / Accepted: 4 May 1998 相似文献
12.
13.
Marie-Hélène Fouchet Eric Guittet Jean A. H. Cognet Jiří Kozelka Corinne Gauthier Marc Le Bret Karel Zimmermann Jean-Claude Chottard 《Journal of biological inorganic chemistry》1997,2(1):83-92
The structure of the second major adduct formed by the antitumor drug cisplatin with DNA, the intrastand cis–Pt(NH3)2{d(ApG)N7–N7} chelate (A*G*), has been investigated using a double-stranded nonanucleotide, d(CTCA*G*CCTC)-d(GAGGCTGAG), by means of NMR
and molecular modeling. The NMR data allow us to conclude that the oligonucleotide is kinked at the platinated site towards
the major groove in a way similar to that observed elsewhere for the G*G*-crosslink in d(GCCG*G*ATCGC)-d(GCGATCCGGC). The
main difference concerns the position of the thymine T(15) complementary to the platinated adenine A*(4). It remains stacked
on its 5′-neighbor C(14), corresponding to the "model E" described previously, whereas in the G*G*-adduct, the cytosine facing
the 5′-G* was found to oscillate between the 5′-branch ("model E") and the 3′-branch ("model C") of the complementary strand.
Two "E-type" models are presented which account for the particular NOE connectivity and for two remarkable upfield NMR signals:
those of the H2′ proton of the cytidine C(3) 5′ to the A*G* chelate, and of the H3 imino proton of T(15), the base complementary
to A*(4). The former shift is attributed to shielding by the destacked A*(4) base, whereas the latter is accounted for by
a swinging movement of the T(15) base between two positions where the imino Watson-Crick hydrogen bond with A*(4) remains
intact and the amino hydrogen bond is disrupted, or vice versa. Possible implications of the structural difference between
the AG and GG adducts of cisplatin in the mutagenic properties of the two adducts are discussed.
Received: 19 August 1996 / Accepted: 4 November 1996 相似文献
14.
Takahiko Fukushige Makoto Nagoshi Yoichi Hachitanda Takaki Ueno Yoshio Zaizen Sachiyo Suita Masazumi Tsuneyoshi Yasuhiko Kaneko Akira Nakagawara 《Virchows Archiv. B, Cell pathology including molecular pathology》1992,62(1):159-166
A new human cell line, termedMuraoka, has been established from the recurrent tumor of a case of congenital primitive neuroectodermal tumor (PNET) arising at
the temporofacial region of a male infant. The microscopic findings of this cell line were epithelioid, and the xenografted
tumor in a nude mouse consisted of the malignant epithelioid cells. Immunohistochemically, the cells were positive for neuron-specific
enolase, S-100 protein, carcinoembryonic antigen, cytokeratin, epithelial membrane antigen, and glial fibrillary acidic protein.
These findings were quite smiliar to those of the epithelioid cells in the original tumor and of the xenografted tumor cells.
Neither chromosomal abnormalities nor N-myc amplification were observed. Morphological differentiation after treatment with
N6-2′-Odibutyryladenosine 3′:5′-cyclic monophosphate (Bt2cAMP), all-trans-retinoic acid (RA), prostaglandin E1 (PGE1, and 5-bromo-2′-deoxyuridine (BrdU) showed two different results. Bt2-cAMP and PGE1 induced neuronal differentiation with the extension of neurites, whereas RA and BrdU predominantly induced Schwannian differentiation
(flat cells). In these respects, the cell lineMuraoka seems to be useful for studying characteristics of PNET as well as for developing the new treatments against such tumors. 相似文献
15.
Peroxynitrite, a potent physiological inorganic toxin, is known to play a critical role in cellular oxidative damage. The
protective role of antioxidant enzymes against peroxynitrite-induced oxidative damage in U937 cells was investigated in control
and cells pre-treated with diethyldithiocarbamic acid, aminotriazole, and oxlalomalate, specific inhibitors of superoxide
dismutase, catalase, and NADP+-dependent isocitrate dehydrogenase, respectively. Upon exposure to 1 mM 3-morpholinosydnomine N-ethylcarbamide (SIN-1), a
generator of peroxynitrite through the reaction between nitric oxide and superoxide anion, to U937 cells, the viability was
lower and the protein oxidation, lipid peroxidation and oxidative DNA damage reflected by an increase in 8-hydroxy-2′-deoxyguanosine,
were higher in the inhibitor-treated cells as compared to the control cells. We also observed the significant increase in
the endogenous production of reactive oxygen species, as measured by the oxidation of 2′7′-dichlorodihydrofluorescin as well
as the significant decrease in the intracellular GSH level in the inhibitor-treated U937 cells upon exposure to SIN-1. These
results suggest that antioxidant enzymes play an important role in cellular defense against peroxynitrite-induced cell death. 相似文献
16.
O. M. Rozhmanova E. V. Dolgaya N. Kh. Pogorelaya I. S. Magura Z. Yu. Tkachouk I. A. Mikhailopulo 《Neurophysiology》2008,40(1):1-5
Using a radioisotope technique, we studied the effect of dephosphorylated 2′,5′-trioligoadenylate (2′,5′ ApApA) on the entry
of sodium ions into cultured human neuroblastoma cells (IMR 32 strain). Short-term (nearly 1 h) action of 2′,5′ ApApA did
not influence the entry of sodium ions through voltage-operated sodium channels in the absence of neurotoxins modulating the
characteristics of these channels (toxin of a scorpion, Leiurus quinquestriatus, + veratrine). At the same time, 2′,5′ ApApA weakened in a dose-dependent manner the entry of sodium ions through sodium
channels opened upon the action of the above neurotoxins. In cells cultured for 22 h in a medium containing 5 · 10−6 M 2′,5′ ApApA, the entry of sodium ions in the absence of neurotoxins was 25% greater, while in the presence of neurotoxins
it was 24% smaller than that in the control cells. Tetrodotoxin (TTX, 4 · 10−7 M) blocked completely sodium entry through sodium channels in cells cultured in the absence of 2′,5′ ApApA, while in cells
cultured in the presence of this adenylate TTX decreased the entry by 64%. It is hypothesized that long-lasting action of
2′,5′ ApApA results in the appearance of voltage-operated TTX-insensitive sodium channels in the plasma membrane of IMR 32
cells. Our data show that 2′,5′ ApApA is capable of modulating to a considerable extent the functioning of mechanisms controlling
transport of sodium ions in cells of human neuroblastoma cells of the IMR 32 strain.
Neirofiziologiya/Neurophysiology, Vol. 40, No. 1, pp. 3–8, January–February, 2008. 相似文献
17.
Wha Ja Cho Jeong Min Shin Jong Soo Kim Man Ryul Lee Ki Sung Hong Jun-Ho Lee Kyoung Hwa Koo Jeong Woo Park Kye-Seong Kim 《Molecules and cells》2009,28(6):521-527
Previously, we have reported tissue- and stage-specific expression of miR-372 in human embryonic stem cells and so far, not
many reports speculate the function of this microRNA (miRNA). In this study, we screened various human cancer cell lines including
gastric cancer cell lines and found first time that miR-372 is expressed only in AGS human gastric adenocarcinoma cell line.
Inhibition of miR-372 using antisense miR-372 oligonucleotide (AS-miR-372) suppressed proliferation, arrested the cell cycle
at G2/M phase, and increased apoptosis of AGS cells. Furthermore, AS-miR-372 treatment increased expression of LATS2, while
over-expression of miR-372 decreased luciferase reporter activity driven by the 3′ untranslated region (3′ UTR) of LATS2 mRNA.
Over-expression of LATS2 induced changes in AGS cells similar to those in AGS cells treated with AS-miR-372. Taken together,
these findings demonstrate an oncogenic role for miR-372 in controlling cell growth, cell cycle, and apoptosis through down-regulation
of a tumor suppressor gene, LATS2. 相似文献
18.
The G2 index of the yeast Cryptococcus neoformans determined by laser scanning cytometer was 2-3 times higher than the budding index during transition to the stationary phase of the culture, indicating that buds emerged in the G2 phase of the cell cycle. To clarify whether buds also emerge in G2 during exponential growth of the culture, DNA content for each cell was measured with a fluorescence microscope equipped with a photomultiplier. The DNA content of cells having tiny buds varied rather widely, depending on growth phases and strains used. Typically, buds of C. neoformans emerged soon after initiation of DNA synthesis in the early exponential phase. However, bud emergence was delayed to G2 during transition to the stationary phase, and in the early stationary phase budding scarcely occurred, although roughly half of the cells completed DNA synthesis. Thus, the timing of budding in C. neoformans was actually shifted to later cell cycle points with progression of the growth phase of the culture. 相似文献
19.
Gon-Sup Kim Yeoung-Gyu Ko Oh-Sung Park Hyoung Joon Park Phil-Ok Koh Kyu-Woan Cho Kwan-Sik Min Hwan-Hoo Seong Chung-Kil Won Jae-Hyeon Cho 《Biotechnology letters》2009,31(8):1173-1181
We identified a 3.4-kb 5′-flanking region of the rPL-I gene and examined its promoter activity using rat trophoblast Rcho-1
cells. A regulatory element between base pairs (bp) −2,487 and −2,310 in the 5′-flanking region was essential for maximum
promoter activity of the rPL-I gene. This regulatory element was further characterized between bp −2,443 to −2,415 and −2,374
to −2,345. Electrophoretic mobility shift analysis showed that the interaction of nuclear extract proteins from differentiated
Rcho-1 cells was inhibited by competition with a GATA-like sequence in the promoter, but not by a mutated GATA sequence. Moreover,
the promoter activity of 2487 eLuc containing two novel GATA sites was significantly elevated by co-transfection of a GATA-2
expression vector in proliferating Rcho-1 cells. Our results demonstrate that GATA-2 is involved in multiple promoter regions
to activate the specific expression of the rPL-I gene in placental tissue.
Gon-Sup Kim and Yeoung-Gyu Ko are contributed equally to this work. 相似文献
20.
We have developed a method for measurement of plasma membrane water permeability (P
f) in intact cells using laser scanning confocal microscopy. The method is based on confocal recording of the fluorescence
intensity emitted by calcein-loaded adherent cells during osmotic shock. P
f is calculated as a function of the time constant in the fluorescence intensity change, the cell surface-to-volume ratio and
the fractional content of the osmotically active cell volume. The method has been applied to the measurement of water permeability
in MDCK cells. The cells behaved as linear osmometers in the interval from 100 to 350 mosM. About 57% of the total cell volume
was found to be osmotically inactive. Water movement across the plasma membrane in intact MDCK cells was highly temperature
dependent. HgCl2 had no effect on water permeability, while amphotericin B and DMSO significantly increased P
f values. The water permeability in MDCK cells transfected with aquaporin 2 was an order of magnitude higher than in the intact
MDCK cell line. The water permeability of the nuclear membrane in both cell lines was found to be unlimited. Thus the intranuclear
fluid belongs to the osmotically active portion of the cell. We conclude that the use of confocal microscopy provides a sensitive
and reproducible method for measurement of water permeability in different types of adherent cells and potentially for coverslip-attached
tissue preparations.
Received: 12 June 1999 / Revised version: 21 February 2000 / Accepted: 25 February 2000 相似文献