共查询到20条相似文献,搜索用时 15 毫秒
1.
S. K. Fisher J. T. Lingenfelser † C. H. Jagoe ‡ C. E. Dallas 《Journal of fish biology》1995,46(3):432-441
We examined the effects of separation and freezing on fish leukocyte and erythrocyte morphology by light microscopy and on DNA content as measured by flow cytometry (FCM). Leukocytes and erythrocytes of largemouth bass Micropterus salmoides were isolated by density gradient centrifugation of whole blood, and frozen in liquid nitrogen in a buffer containing DMSO as a cryopreservative. The coefficient of variation (CV) of the G0 /G1 peak of the cells was used to assess variation in nuclear DNA content within cell populations before and after separation and freezing treatments. In erythrocytes, the CV did not change significantly (P>0.05) when nuclei were isolated and stained without freezing or when erythrocytes were frozen prior to nuclear isolation and staining. In leukocytes, freezing and thawing prior to isolation and staining of nuclei significantly increased the CV (P<0.05), and produced hyperdiploid shoulders of the G0 /G1 peak. However, the CV of leukocyte nuclei that were isolated and stained prior to freezing and the CV of non-frozen leukocyte nuclei did not differ (P>0.05). Microscopy showed that the freezing protocol had little effect on erythrocyte morphology, but caused irregular swelling in leukocytes. Freezing intact leukocytes also significantly (p<0.05) altered the apparent distribution of cells among the phases of the cell cycle as measured by FCM. The distributions of leukocyte nuclei that were isolated and stained prior to freezing were not different to non-frozen leukocytes. DNA measurements of nucleated blood cells are widely used in physiological, genetic and toxicological studies. Our results suggest that whole blood and erythrocytes for use in such studies can be frozen whole using a simple protocol, but leukocyte nuclei must be isolated and stained before freezing to avoid serious artifacts. 相似文献
2.
A Rapid Automated Stathmokinetic Method For Determination of In Vitro Cell Cycle Transit Times 总被引:2,自引:0,他引:2
To provide a rapid method for examining cell cycle dynamics, we utilized continuous exposure of Chinese hamster ovary cells and human colon cancer cells to colcemid to block cycling cells in metaphase, suppressing re-entry into G1. Changes in cell cycle compartment distribution were monitored by DNA flow cytometry. Analysis of the rate of G2+ M compartment accumulation after addition of colcemid permitted calculation of all cycle transit parameters. These compared favorably with data in the same cell lines determined by the fraction of labeled mitoses technique. Serial assessment of DNA flow cytometry after addition of colcemid permits rapid quantitation of cycle traverse rates. 相似文献
3.
Asynchronous 9L cells were separated into relatively homogeneously-sized populations using centrifugal elutriation with both
a conventional collection method and a long collection method. A substantial increase in the homogeneity of the volume distributions
and in the degree of synchrony of the separated fractions was obtained using the long collection method. Autoradiographic
data indicated that fractions containing ≥97% G1 cells, ≥80% S cells, and 70–75% G2 cells could be routinely recovered with this procedure. Recovery in these fractions varied from 5 to 8% of the total number
of cells elutriated. The colony forming efficiency (CFE) of cells from fractions representing each phase of the cell cycle
was a constant 60–70%, which was comparable to the 60–80% usually found for asynchronous 9L cells. The percentage of cells
in the G1, S, and G2 phases in the elutriated fractions was more accurately determined from the volume distribution than from computer fits of
the DNA histogram obtained from flow cytometry. In general, the degree of synchrony was related to the coefficient of variation
(CV) of the volume distributions of the elutriated fractions. The CV was about 14% for all elutriated fractions. When the
≥97% G1 population was allowed to progress to S and G2, the CVs were about 17 and 20.2%, respectively. Thus, the best nonperturbing method for obtaining synchronous 9L cells in
the S or G2 phases was direct elutriation with the long collection method. 相似文献
4.
Yu. G. Pichugin K. A. Semiyanov A. V. Chernyshev I. G. Palchikova L. V. Omelyanchyuk V. P. Maltsev 《Cell and Tissue Biology》2012,6(3):302-308
This work has proposed a new theoretical approach to analysis of histograms of DNA content, which are obtained by the method
of flow cytometry, in cells of Drosophila melanogaster imaginal discs. The precision of measurements of the DNA amount in G1 and G2(M) phases has been shown to be limited by precision of instrument tuning of zero of the flow cytometer. Use of the calculative
zero of the flow cytometer and of dividing cells as standards of the DNA content is able to increase severalfold the precision
of the DNA measurements in nuclei of the species. Comparative analysis of errors of various methods of measurement of the
DNA content in cell nuclei is also performed. For methods of flow fluorescent cytometry, confocal scanning, and cytophotometry
of the Feulgen-stained nuclei, it has been shown that, at present, the mean square errors of the DNA content measurements
are within the interval of values considered acceptable for biological studies (0.02 < CV < 0.06). 相似文献
5.
D. C. Allison M. Chakerian P. F. Ridolpho S. Anderson S. Curley M. E. Wilder J. Robertson 《Cell proliferation》1987,20(3):273-290
Abstract. Flow cytometry of cellular DNA content provides rapid estimates of DNA distributions, i.e. the proportions of cells in the different phases of the cell cycle. Measurements of DNA alone, however, yield no kinetic information and can make it difficult to resolve the cell cycle distributions of normal and transformed cells present in tumour biopsy specimens. The use of absorption cytophotometry of the Feulgen DNA content and [3H]TdR labelling of the same nuclei provides objective criteria to distinguish the ranges of DNA content for G0/G1, S, and G2/M cells. We now report on a study in which we combined flow and absorption cytometry to resolve the cell cycle distributions of host and tumour cells present in biopsy specimens of MCa-11 mouse mammary tumours labelled in vivo for 0.5 hr with [3H]TdR. A similar analysis of exponential monolayer cultures, labelled for 5 min with [3H]TdR under pulse-chase conditions, revealed a highly synchronous traversal of almost all cells through the different phases of the cell cycle. Combination of the flow and absorption methods also allowed us to detect G2 tumour cells in vivo and a minor tumour stem-line in vitro, to show that these two techniques are complementary and yield new information when they are combined. 相似文献
6.
The influence of cisplatin, an anticancer agent, on DNA synthesis and cell cycle progression of a cisplatin-resistant cell line was investigated. Cell cycle analysis using flow cytometry showed that cytotoxic concentrations of cisplatin caused a transient inhibition of parental HeLa cells at S phase, followed by accumulation at G2 phase. In contrast, the resistant cells progressed through the cell cycle without being affected by the same treatment. However, cell cycle distributions were the same in the resistant and the parental cells at IC50, the drug concentration inhibiting cell growth by 50%. Studies using a [3H]thymidine incorporation technique also demonstrated a transient inhibition of DNA synthesis in HeLa cells by cisplatin; such inhibition was greatly reduced in the resistant cells. These data argue for the hypothesis that the inhibition of DNA synthesis is important in determining cisplatin-induced cytotoxicity. In addition, the accumulation of cells at G0/G1 by serum starvation was not effective in the resistant cells compared to the parental cells, suggesting that the control of cell cycle exiting is also altered in the resistant cells. Taken together, these results support the notion that alterations in cell cycle control, in particular G2 arrest, are important in determining the sensitivity or resistance of mammalian cells to cisplatin and may have a role in clinical protocols. 相似文献
7.
Reversible accumulation of plant suspension cell cultures in g(1) phase and subsequent synchronous traverse of the cell cycle 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Plant physiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Conia J Alexander RG Wilder ME Richards KR Rice ME Jackson PJ 《Plant physiology》1990,94(4):1568-1574
The induction of DNA synthesis in Datura innoxia Mill. cell cultures was determined by flow cytometry. A large fraction of the total population of cells traversed the cell cycle in synchrony when exposed to fresh medium. One hour after transfer to fresh medium, 37% of the cells were found in the process of DNA synthesis. After 24 hours of culture, 66% of the cells had accumulated in G2 phase, and underwent cell division simultaneously. Only 10% of the cells remained in G0 or G1. Transfer of cells into a medium, 80% (v/v) of which was conditioned by a sister culture for 2 days, was adequate to inhibit this simultaneous traverse of the cell cycle. A large proportion of dividing cells could be arrested at the G0 + G1/S boundary by exposure to 10 millimolar hydroxyurea (HU) for 12 to 24 hours. Inhibition of DNA synthesis by HU was reversible, and when resuspended into fresh culture medium synchronized cells resumed the cell cycle. Consequently, a large fraction of the cell population could be obtained in the G2 phase. However, reversal of G1 arrested cells was not complete and a fraction of cells did not initiate DNA synthesis. Seventy-four percent of the cells simultaneously reached 4C DNA content whereas the frequency of cells which remained in G0 + G1 phase was approximately 17%. Incorporation of radioactive precursors into DNA and proteins identified a population of nondividing cells which represents the fraction of cells in G0. The frequency of cells entering G0 was 11% at each generation. Our results indicate that almost 100% of the population of dividing cells synchronously traversed the cell cycle following suspension in fresh medium. 相似文献
8.
Frank Traganos Jianping Gong Barbara Ardelt Zbigniew Darzynkiewicz 《Journal of cellular physiology》1994,158(3):535-544
Staurosporine (SSP) is an inhibitor of a variety of protein kinases with an especially high affinity towards protein kinase C. Whereas SSP has been shown to halt the cell cycle progression of various normal, nontransformed cell types in G1, most virus transformed or tumor cells are unaffected in G1 but arrest in G2 phase. SSP has also been observed to increase the appearance of cells with higher DNA content, suggestive of endoreduplication, in cultures of tumor cells. Using multivariate flow cytometry (DNA content vs. expression of cyclin B, nucleolar p120 protein, or protein reactive with Ki-67 antibody) which makes it possible to discriminate cells with identical DNA content but at different phases of the cycle, we have studied the cell cycle progression of human lymphocytic leukemic MOLT-4 cells in the presence of 0.1 μM SSP.MOLT-4 cells did not arrest in G1 or G2 phase in the presence of the inhibitor. Rather, they failed to undergo cytokinesis, entering G1 phase at higher DNA ploidy (tetraploidy; G1T), and then progressed through ST (rereplication) into G2T and MT. The rates of entrance to G2 and G2T were essentially identical, indicating that the rates of cell progression through S and ST as well as through G2 and G2T, respectively, were similar. Cells entrance to mitosis and mitotic chromatin condensation were also similar at the diploid and tetraploid DNA content level and were unaffected by 0.1 μM SSP. No evidence of growth imbalance (altered protein or RNA to DNA ratio) was observed in the case of tetraploid cells. The data show that, in the case of MOLT-4 cells, all events associated with the chromosome or DNA cycle were unaffected by SSP; the only target of the inhibitor appears to be kinase(s) controlling cytokinesis. © 1994 Wiley-Liss, Inc. 相似文献
9.
In the 3-d-old 2-mm root tip of Pisum sativum L. cv. Lincoln the percentage of actively proliferating cells is estimated to be 70%. The remaining cells are non-cycling
and arrested with 2C and 4C DNA content in G0 and in G2Q, respectively. In this work we studied the kinetic significance of these quiescent cells, using the sorting capabilities
of flow cytometry and immunofluorescence techniques to detect the proliferation marker PCNA (proliferating cell nuclear antigen)
inside cells within the different cell-cycle compartments. While in animal cells, PCNA is present at a high level only in
actively proliferating cells, in 3-d-old pea root tips 95% of the cells are PCNA-positive. After flow cytometry and sorting
of pea non-cycling nuclear populations, all G2Q nuclei appeared strongly PCNA-positive, indicating that these cells had recently left the cell cycle. By contrast, most
G0 nuclei showed a low level of PCNA immunofluorescence intensity, as measured by image analysis, with about 25% of the nuclei
being PCNA-negative. This small percentage was found to correspond to root cap cells, as could be observed in the root tip
section. These are the only cells in the root apical region which are fully differentiated and which, therefore, lack the
competence to enter the cell cycle. In contrast, the more or less PCNA-positive G0 nuclei could represent a kinetically heterogeneous population of cells competent to proliferate, but which have either recently
left the cell cycle or are progressing to the G0-G1 transition.
Received: 6 November 1996 / Accepted: 14 January 1997 相似文献
10.
Exposure to hyperbaric oxygen induces cell cycle perturbation in prostate cancer cells 总被引:12,自引:0,他引:12
John E. Kalns Edward H. Piepmeier 《In vitro cellular & developmental biology. Animal》1999,35(2):98-101
Summary Cell cycle synchronization of tumor cells by exposure to hyperbaric oxygenation (HBO) may increase the efficacy of chemotherapy
or radiation by placing cells into a chemosensitive portion of the cycle. The purpose of the current study was to examine
oxygen pressure-dependent relationships with respect to the cell cycle in prostate tumor cells in vitro. LNCaP cells were
grown in an incubator at 21% O2 and then exposed to 100% oxygen at pressures up to 6 atmospheres (atm) for 1.5 h. Cells were then returned to the incubator
and evaluated for DNA content by propidium iodide and new DNA synthesis with a pulse-chase experiment. Cell cycle effects
were evaluated by flow cytometry. Exposure to HBO increased the percentage of cells synthesizing new DNA in a dose-dependent
fashion: 0 atm, 44%; 6 atm, 65%. Cells that synthesize new DNA accumulate in G2/M as a function of partial pressure of oxygen. These results suggest that HBO induces cells to enter the cell cycle and accumulate
in G2/M. Cell cycle synchronization and entry of senescent cells into the cell cycle suggest that HBO may be a useful adjuvant
to chemotherapy or radiation in the treatment of prostate cancer. There are two potential mechanisms of action that may make
HBO efficacious in the treatment of prostate cancer. HBO may potentiate cancer chemotherapeutic agents that cause damage to
DNA during DNA synthesis or HBO may inhibit cell division causing accumulation in G2/M. 相似文献
11.
Simian virus 40 (SV40) is capable of inducing cellular DNA synthesis in permissive and nonpermissive cells. Utilizing flow cytometry, we analyzed the DNA content changes in two diploid human cell strains and two monkey cell lines. The osteogenesis imperfects (OI) human skin fibroblasts were induced into DNA synthesis, and within one to two cell generations, a polyploid cell population was produced. With WI-38 phase II cells, a similar pattern of increased cycling of cells into DNA synthesis was observed; however, the majority (~60%) of the cells were blocked in the G2 + M phase of the cell cycle. At later time intervals, an increase in the G1 population was demonstrated. The two monkey cell lines responded to SV40 virus with an accumulation of cells in the G2 + M phase of the cell cycle. Thus, two diploid human cell strains exhibited different cell cycle kinetics early after infection with SV40 virus. The one strain (WI-38) behaved similarly to the two monkey cell lines studied. The other strain (OI) responded similarly to nonpermissive (transformin) cells infected with SV40 virus. 相似文献
12.
《Cell cycle (Georgetown, Tex.)》2013,12(2):408-418
During mouse embryonic development germ cells proliferate extensively until they commit to the male or female pathway and arrest in mitosis or meiosis respectively. Whilst the transition of female germ cells exiting the mitotic cell cycle and entering meiosis is well defined histologically, the essential cell cycle proteins involved in this process have remained unresolved. Using flow cytometry we have examined the entry of female germ cells into meiosis, their termination of DNA synthesis and entry into prophase I. Analysis of key G2/M cell cycle proteins revealed that entry into meiosis and cell cycle exit at G2/M involves repression of G2/M promoting Cyclin B1, coincident upregulation of G2/M repressing Cyclin B3 and robust establishment of the ATM/CHK2 pathway. By contrast we show that the ATR/CHK1 pathway is activated in male and female germ cells. This data indicates that an important G2/M surveillance mechanism operates during germ cell proliferation and that passage into meiotic G2/M involves the combined repression of G2/M through Cyclin B3 and activation of the key G2/M checkpoint regulatory network modulated through ATM and CHK2. This work shows that the core regulatory machinery that controls G2/M progression in mitotic cells is activated in female mouse germ cells as they enter meiosis. 相似文献
13.
M. G. Taylor I. K. Vasil 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1987,74(6):681-686
Summary Mesophyll cell nuclei isolated from leaves of Pennisetum purpureum were analysed by flow cytometry to determine the nuclear DNA content and the percentage of cells in different phases of the cell cycle. Samples taken from base, middle and tip regions of leaves 2 to 8 (leaf 1, which was adjacent to the meristem, was too small to sample) showed no significant differences in the amount of DNA per G1 nucleus due to either age or position. The average amount of DNA per G1 nucleus was 5.78 pg. Although the majority of cells for each sample were in G1, samples taken from older leaves had higher percentages of cells in G2 and S phases. More specifically, base and middle regions of older leaves had a higher percentage of cells in G2 than all three positions in younger leaves. Electrophoretic analysis of nuclear DNA from leaves 2 to 7 showed no evidence of degradation or difference in fragment size for any sample or position. This study was compared to previous work on the relationship between leaf age and embryogenic competence in Pennisetum purpureum. The results suggest that changes in the cell cycle, and/or a loss or fragmentation of the nuclear DNA, are not responsible for loss of embryogenic competence in mature leaf tissue. 相似文献
14.
Suzanne M. Morris Olen E. Domon Lynda J. McGarrity Anane Aidoo Ralph L. Kodell Daniel A. Casciano 《Cell biology and toxicology》1993,9(1):77-83
Current studies in our laboratory are designed to determine the frequency of genotoxic responses induced in lymphocytes isolated from Fischer 344 rats. To evaluate the effect of a model compound, N-ethyl-N-nitrosourea (ENU), on the cell-cycle distribution of spleen lymphocytes, 8-week old, female Fischer 344 rats were injected i.p. with ENU and sacrificed 1, 2, 4, and 6 weeks afterexposure. Four replicate cultures per dose per exposure period were established and cells were cultured for 66 hr. Colcernid, an agent which blocks cells in mitosis and induces an accumulation of cells in the G2 + M peak, was added to two of the four cultures as a positive control. After a 3 hr incubation, the cells were harvested, the nuclei stained with propidium iodide, and the DNA content of the individual nuclei was quantified by flow cytometry. As expected, exposure to Colcemid resulted in an accumulation of cells in the G2 + M phase of the cell cycle, which was accompanied by a decrease in the Go + GI population. The increase in the G2 + M population was significant (p < 0.05) in cultures of lymphocytes assayed at 4 and 6 weeks after exposure. The eflect of increasing ENU concentratiorl was an increase in the percentage of Sphase cells (p =0.05) and a decrease (p < 0.02) in the percentage of G0 + G1 cells. This finding was observed only in those lymphocytes isolated 1 week after exposure. These findings indicate that flow cytometric analysis of the distribution of cells within the cell-cycle may provide insight into the eflects of toxicant exposure on mamnzalian cells.Abbreviations BRdU
bromodeoxyuridine
- ENU
N-ethyl-N-nitrosourea
- FCM
flow cytometry
- PHA
phytohemagglutinin
- PI
propidium iodide 相似文献
15.
Thomas A. Hamilton Marvin Fishman Gail Crawford A.Thomas Look 《Cellular immunology》1982,69(2):363-373
We have examined the sensitivity of proliferating lymphoid cells in different phases of the cell cycle to macrophage-mediated cytostatic activity. These studies evaluated the ability of target cells enriched in individual cell cycle phases to pass into the next phase during brief (2–6 hr) periods of coculture with activated or nonactivated peritoneal macrophages. Both normal (concanavalin A-stimulated spleen cells) and neoplastic (Gross virus-induced thymic lymphoma) cells were analyzed. Spleen cells or lymphoma cells were first separated by centrifugal elutriation into populations highly enriched for G1, S, or G2/M phases of the cell cycle and cultured in the presence of nonactivated or activated macrophages for periods of 2, 4, or 6 hr. The cellular DNA content of recovered nonadherent target cells was then analyzed by flow cytometry after staining with propidium iodide. Macrophage contamination of target cell populations was insignificant under these conditions. Nonactivated macrophages did not affect target cell cycle traverse when compared with target cells cultured alone. Activated macrophage mediated cytostatic activity resulted in complete block of the transition of cells in G1 phase into S phase and of the further accumulation of DNA by cells in early S phase. Cells already in mid to late S phase were able to continue DNA replication at rates nearly equivalent to control cells. There was no inhibition of the passage of cells through G2 or mitosis. These effects were seen by as early as 2 hr of macrophage-target cell coculture and both normal and neoplastic cells exhibited identical patterns of cell cycle phase sensitivity. 相似文献
16.
Summary The varying sensitivity to radiation in the different phases of the cell cycle was investigated using L-929 cells of the mouse. The cells were synchronized by mechanical selection of mitotic cells. The synchronous populations were X-irradiated with a single dose of 10 Gy in the middle of the G1-phase, at the G1/S-transition or in the middle of the S-phase, respectively. The radiation effect was determined in 2 h intervals a) by14C-TdR incorporation (IT) into the DNA, b) by autoradiography (AR), c) by flow cytometry (FCM). The incorporation rate decreased in all three cases, but the reasons appeared to be different, as can be derived from FCM and AR data: After irradiation in G1, a fraction of cells was prevented from entering S-phase, after irradiation at G1/S a proportion of cells was blocked in the S-phase, and after irradiation in S, DNA synthesis rate was reduced. As a consequence of these effects, the mean transition time through S-phase increased. The G2 blocks, obtained after irradiation at the three stages of the cycle were also different: Cells irradiated in G1 are partly released from the block after 10 h. Irradiation at G1/S caused a persisting accumulation of 50% of the cells in G2, and for irradiation in S more than 80% of the cells were arrested in G2. 相似文献
17.
Genta Amakawa Kenzo Ikemoto Hideaki Ito Tomoko Furuya Kohsuke Sasaki 《The journal of histochemistry and cytochemistry》2013,61(10):699-705
Two-color fluorescence in situ hybridization (FISH) with chromosome enumeration DNA probes specific to chromosomes 7, 11, 17, and 18 was applied to CAL-51 breast cancer cells to examine whether the fluorescence intensity of FISH spots was associated with cell cycle progression. The fluorescence intensity of each FISH spot was quantitatively analyzed based on the cell cycle stage determined by image cytometry at the single-cell level. The spot intensity of cells in the G2 phase was larger than that in the G0/1 phase. This increased intensity was not seen during the early and mid S phases, whereas the cells in the late S phase showed significant increases in spot intensity, reaching the same level as that observed in the G2 phase, indicating that alpha satellite DNA in the centromeric region was replicated in the late S phase. Thus, image cytometry can successfully detect small differences in the fluorescence intensities of centromeric spots of homologous chromosomes. This combinational image analysis of FISH spots and the cell cycle with cell image cytometry provides insights into new aspects of the cell cycle. This is the first report demonstrating that image cytometry can be used to analyze the fluorescence intensity of FISH signals during the cell cycle. 相似文献
18.
Summary Using flow cytometry, spherulating nuclei of Physarum isolated at the beginning of spherule wall formation were found to exhibit a DNA content corresponding to the G2 phase of the cell cycle, although 8% lower. Before the first mitosis after spherule germination, a very slight incorporation of 3H thymidine into DNA was observed that was too weak to correspond to S phase, strongly suggesting that nuclei are stopped in G2 phase inside the spherules. The lower value of nuclear DNA content found using flow cytometry of germinating spherules may not be related to DNA quantity, but may be due to a difference in chromatin organization during growth or spherulation, resulting in interference with the staining. 相似文献
19.
Alan M. Miller Beverly Steele Allen Vincent Ziboh 《Journal of cellular physiology》1997,170(3):309-315
The cell line M-07e requires either Interleukin-3 (IL-3) or granulocyte-macrophage colony stimulating factor (GM-CSF) for proliferation in vitro. Cells deprived of growth factor for up to 48 hours remain viable but no longer divide. The growth-factor-deprived M-07e cells begin to divide within 48 hours of reexposure to IL-3. Flow cytometric analysis of M-07e cells labeled with hypotonic propidium iodide demonstrates that the percentage of cells undergoing DNA synthesis decreases from 24%, in a log phase population of IL-3 stimulated cells, to 1% when cells are deprived of IL-3 for 24 hours. IL-3-deprived cells accumulate predominantly in a flow cytometry peak representative of G0/G1. DNA synthetic activity, as determined by tritiated thymidine uptake and flow cytometry, resumes between 12 and 18 hours after reexposure to IL-3, reaching a peak of up to 40% by 24 hours and returning to log phase levels by 72 hours. Prior to initiation of DNA synthesis, increases are seen in mRNA levels for five-lipoxygenase-activating protein (FLAP). Following reexposure to IL-3, a rapid time-dependent biosynthesis of leukotriene D4 (LTD4) is induced by M-07e cells. When IL-3 is added in the presence of any of three lipoxygenase inhibitors tested (Piriprost, caffeic acid, nordihydroguiaretic acid) or FLAP inhibitor, MK-886, there is dose-dependent inhibition of the resumption of proliferation and of DNA synthesis. Flow cytometric cell cycle analysis demonstrates that the inhibited cells remain in the G0/G1 population and do not progress through the cell cycle. These results are consistent with our previous observation that an intact lipoxygenase pathway is necessary for hematopoietic growth-factor-stimulated colony formation of normal bone marrow myeloid progenitors and suggest that the induction of a lipoxygenase metabolite or metabolites is necessary for myeloid cells to progress through the cell cycle when stimulated by a hematopoietic growth factor. J. Cell. Physiol. 170:309–315, 1997. © 1997 Wiley-Liss, Inc. 相似文献
20.
Protoplasts of cotton cotyledons were isolated and culturedto undergo cell wall regeneration and cell division. DNA contentand cell cycle parameters of nuclei from cotyledons and/or protoplastswere determined by flow cytometry. The DNA content of cotton,Gossypium hirsutum L., was estimated to be 4·34±0·12pg DNA per nucleus. There was a strong positive correlation between G2 or Sand G2,and cell wall regeneration and cell division and a strong negativecorrelation between G1, and cell wall regeneration and celldivision of cotton cotyledon protoplasts. The cell cycle statusof cotyledons changes during their development; as the cotyledonsenlarge, the proportion of cells in G0 and G1 phases of thecell cycle increases. The implication of these results in relationto protoplast growth and development is discussed. Key words: Cell cycle parameters, cell wall regeneration, cell division, flow cytometry, Gossypium 相似文献