bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liver cells can spontaneously resume proliferation in long‐term quiescent primary cultures
Authors: Lombard M.‐N. , Houssais J.‐F. , Decloitre F. , Dutrillaux B. 
Published: May 2008

AbstractWe report here data on the spontaneous resumption of proliferation in long‐term primary cultures and we show that the proliferating areas are neoplastic. Normal rat hepatocytes were explanted in serum‐supplemented Ham F12 medium and maintained over 8 months without transfer. The cells remained quiescent for the first 10 weeks and they were not tumorigenic when injected into nude mice. Later, without any modification of the culture conditions or transfer, progressive changes spontaneously occurred. Foci of dividing cells were detected, some displaying y‐glutamyl‐transpep‐tidase (γ‐GT) activity and F‐actin fragmentation. These proliferating foci overcame the quiescent population. When injected into nude mice, the 15–week‐old primary cultures were highly tumorigenic, with a 3–6 week latency for tumour formation. Furthermore, a cell line was derived from a primary culture started with a liver carcinogen promoter (biliverdin‐enriched medium). This cell line proliferated rapidly and differed from a liver epithelial line, also established from our primary cultures, in its 1 karyotype (hy‐perploidy and translocation on chromosome 3), 2 requirement for arginine to proliferate, 3γ‐GT positive reaction correlated to changes in actin fibre pattern, 4 sensitivity to protease inhibitors (i.e. α2 macroglobulin, PMSF) and 5 tumorigenicity. Long‐term primary cultures and the karyotypically defined cell line are useful tools for further studies on in vitro genetic deviations.
A mathematical model of glioma growth: the effect of chemotherapy on spatio‐temporal growth
Authors: Tracqui P. , Cruywagen G. C. , Woodward D. E. , Bartoo G. T. , Murray J. D. , Alvord E. C. 
Published: May 2008

AbstractDuring the past two decades computerized tomography (CT) and magnetic resonance imaging (MRI) have permitted the detection of tumours at much earlier stages in their development than was previously possible. In spite of this earlier diagnosis the effects of earlier and more extensive treatments have been difficult to document. This failure has led to an increasing awareness of the importance of infiltration of glioma cells into surrounding grossly normal brain tissue such that recurrence still occurs. In this paper a simple mathematical model for the proliferation and infiltration of such tumours is introduced, based in part on quantitative image analysis of histological sections of a human brain glioma and especially on cross‐sectional area/volume measurements of serial CT images while the patient was undergoing chemotherapy. The model parameters were estimated using optimization techniques to give the best fit of the simulated tumour area to the CT scan data. Numerical solution of the model on a two‐dimensional domain, which took into account the geometry of the brain and its natural barriers to diffusion, was used to determine the effect of chemotherapy on the spatiotemporal growth of the tumour.
The GC factor regulates the expression of the insulin‐like growth factor‐I receptor
Authors: Morrione A. , DeAngelis T. , Baserga R. 
Published: May 2008

AbstractWe have transfected a plasmid expressing the transcriptional regulator GC Factor (GCF) into cell lines and have found that the GCF: 1 causes a decrease in the levels of insulin‐like growth factor I receptor (IGF‐IR) mRNA; 2 causes a decrease in the number of IGF‐IRs; and 3 represses the activity of the IGF‐IR promoter. In addition, we show that the regulation of IGF‐IR expression by GCF plays a physiological role in the control of cellular proliferation in vitro.
cAMP and PMA enhance the effects of IGF‐I in the proliferation of endometrial adenocarcinoma cell line HEC‐1‐A by acting at the G1 phase of the cell cycle
Authors: Talavera F. , Bergman C. , Pearl M. L. , Connor P. , Roberts J. A. , Menon K. M. J. 
Published: May 2008

AbstractThe present study was undertaken to determine whether endometrial cancer cell line HEC‐1‐A differ from nontransformed cells, in that the cAMP and protein kinase C pathways may enhance IGF‐I effects in mitogenesis by acting at the G1 phase of the cell cycle instead of G0. Immunofluorescence staining of HEC‐1‐A cells using the proliferating cell nuclear antigen (PCNA) monoclonal antibody and flow cytometric analysis determined that HEC‐1‐A cells do not enter the G0 phase of the cell cycle when incubated in a serum‐free medium. Approximately 51% of the cells were in G1, 12% were in S and 37% in G2 phase of the cell cycle prior to treatment. Forskolin and phorbol‐12‐myristate 13‐acetate (PMA) were used to stimulate cAMP production and protein kinase C activity, respectively. IGF‐I, forskolin and PMA each increased (P <0.01) [3H]‐thymidine incorporation in a dose and time dependent manner. The interaction of forskolin and PMA with IGF‐I was then determined. Cells preincubated with forskolin or PMA followed by incubation with IFG‐I incorporated significantly more (P <0.01) [3H]‐thymidine into DNA than controls or any treatment alone. It is concluded that forskolin and, to a lesser extent, PMA exert their effect at the G1 phase of the cycle to enhance IGF‐I effects in cell proliferation.
Interleukin‐3 or erythropoietin induced nuclear localization of protein kinase C β isoforms in hematopoietic target cells
Authors: Mason‐Garcia M. , Harlan R. E. , Mallia C. , Jeter J. R. , Steinberg H. B. , Fermin C. , Beckman B. S. 
Published: May 2008

AbstractProtein kinase C (PKC) has been implicated in the signal transduction pathways for the biological effect of both interleukin‐3 (IL‐3) and erythropoietin (EPO) in hematopoietic target cells. The goal of this study was to identify specific classical isoforms of PKC and their localization in hematopoietic cells in response to the growth factors, IL‐3 or EPO. In addition to murine fetal liver cells as a source of normal erythroid progenitor cells, we have utilized the B6SUt.EP cell line, a non‐transformed hematopoietic cell line that requires IL‐3 for proliferation, but for which EPO can substitute as a growth factor. With polyclonal antibodies prepared against peptide sequences specific for the α, βI, βII and γ isoforms of PKC, we have identified βI and βII as the predominant nuclear isoforms in target cells that proliferate in response to IL‐3 or EPO.
Cell cycle perturbation by sodium butyrate in tumorigenic and non‐tumorigenic human urothelial cell lines assessed by flow cytometric bromodeoxyuridine/DNA analysis
Authors: Larsen J. K. , Christensen I. J. , Kieler J. 
Published: May 2008

AbstractThe effect of sodium butyrate on cell proliferation was studied in eight human urothelial cell lines differing in transformation grade (TGr): Hu 1752 (mortal, TGr I); HCV29 (immortal and tumorigenic, TGr II); HCV29T, T24, T24A, T24B, Hu 961A and Hu 1703He (tumorigenic, TGr III). In all cell lines, except Hu 1752, addition of 4 mm sodium butyrate at 18 h after replating resulted in a significantly decreased population of adherent cells after a further 24–48 h. This might partially be explained by detachment of cells, probably mainly S phase cells, from the substrate in the lines HCV 29, HCV29T, Hu 961A and Hu 1703He. Flow cytometric DNA analysis of the adherent cell population showed that all TGr II and III urothelial cell lines were DNA aneuploid, and that butyrate perturbed the cell cycle distribution in these cell lines, mainly by a decrease of the S phase fraction. Flow cytometric bromodeoxyuridine (BrdUrd)/DNA analysis of continuously BrdUrd labelled cultures, using a ‘washless’ BrdUrd/DNA staining technique, showed that butyrate inhibited the G0/1‐S phase transition, indicated by a delayed depletion of BrdUrd negative G0/1 cells in the cell lines HCV29, HCV29T, T24B, Hu 961A and Hu 1703He. BrdUrd/DNA analysis further showed that butyrate inhibited the G2M‐G0/1 phase transition, indicated by a pronounced accumulation of BrdUrd positive G2M cells in the cell lines HCV29T, T24B, Hu 961A and Hu 1703He. Microscopy of HCV29T and Hu 961A cells indicated that this block did not occur in mitosis. The parental cell line T 24 and the cell line T 24 A did not show an accumulation of BrdUrd negative G0/1 cells or BrdUrd positive G2M cells like that occurring in the derived cell line T 24B.
Influence of long‐term limitation of cell proliferation on the cell cycle duration
Authors: Blokhin A. V. , Khalyavkin A. V. 
Published: May 2008

AbstractThe hypothesis was tested that constant, long‐term inhibition of cell proliferation is the primary cause of cellular senescence. Mouse L‐929 fibroblasts were maintained in confluent cultures for periods of 6 and 12 months with cell viability maintained by regular replacement of medium and serum. The mitotic activity of the cell population under these conditions was one mitosis per 104 cells. No changes in the duration of the cell cycle were observed when, following long‐term quiescence, the cell were replated and grown at low cell density. The results do not support the hypothesis that prolonged suppression of cell proliferation induces cell senescence.
Impaired chromosome segregation in plant anaphase after moderate hypomethylation of DNA
Authors: Leyton C. , Mergudich D. , De La Torre C. , Sans J. 
Published: May 2008

Abstract10−6 M and 10−5 M 5‐azacytidine, demethylated around 9% and 17% of the 5‐methylcytosine residues found in Allium cepa L. native DNA, respectively. Both treatments stimulated RNA synthesis in the cells of root meristems. On the other hand, the 10−5 M treatment gave rise to multiple chromosomal anomalies in mitosis before any fall in the mitotic index was detectable, but no chromosomal breaks were ever seen.Serious lesions involved in chromatids and segregation in anaphase were preferentially found after hypomethylation of DNA sequences replicated in the second half of the previous S period: (i) sister telomeres remained unresolved at the cell equator while kinetochores had reached the poles, (ii) whole unsegregated chromosomes were pulled to one of the poles by obviously disfunctional kinetochores, resulting in an unbalanced distribution of chromatids, (iii) unsegregated chromosomes in other cells remained at the spindle equator as if kinetochores were nonfunctional, while cytoplasmic division took place before their migration to the poles. Frequently, a growing cytokinetic plate randomly cut the unsegregated chromosomes, giving rise to aneuploid nuclei. These anaphase failures are a firm basis to explain why the 10−5 M treatment selectively depressed the rate of cell proliferation in these cells in the long run. On the other hand, if hypomethylation occurred at the first half of the previous S period, enlarged chromosomal segments were evident in most metaphases, while chromosome laggards and bridges were recorded in anaphase at rather similar frequencies after the different 5‐azacytidine treatments. These data were consistently obtained both in the native mononucleate cells of meristems and in one subpopulation of synchronous cells labelled as binucleate by 5 mm caffeine.
The effects of irradiation at different times of the day on rat intestinal goblet cells
Authors: Becciolini A. , Balzi M. , Fabbrica D. , Potten C. S. 
Published: May 2008

AbstractQuantitative changes in jejunal goblet cells were studied in control and whole body irradiated rats using PAS‐Alcian blue staining of crypt sections. A circadian dependence was observed when control animals were killed at different times during the light/dark cycle. Irradiation with 3 Gy produced a 2–3‐fold increase within 36 h in goblet cells relative to controls, followed by a reduction to very low levels. There was a return to pre‐treatment levels later than was observed for the columnar cells. The present results on the pattern of response of goblet cells and those of brush border enzyme activity are consistent with the hypothesis that ionizing radiation can influence differentiation. In fact during the first hours after irradiation an early induction of differentiation is evident while during the early repopulation phase columnar cells prevailed relative to the goblet cells. Only at later times were normal differentiation patterns seen. Groups of animals exposed to the same dose of radiation at different times of the day showed similar general patterns of behaviour even if the group irradiated at midnight showed a more marked and longer lasting injury.
Inhibition of Tobacco Mosaic Virus Reproduction in Isolated Tobacco Protoplasts by Means of Pancreatic Ribonuclease
Authors: Zhuravlev Yu. N. , Pisetskaya N. F. , Ledneva V. A. 
Published: May 2008

AbstractTreatment of protoplasts with RNase solutions (1 — 100 μg/ml) sharply reduced their ability to support TMV reproduction. Treatment of protoplasts with RNase both prior to and after inoculation with the virus, and also treatments of varying duration, had approximately the same effect on inhibiting TMV reproduction; however, the effect became sharply intensified with higher RNase concentrations. The authors assume that the RNase inhibitive effect in protoplasts is ensured by the specific structure of this relatively small positively‐charged macromolecule, not by its enzymic properties. The RNase molecules apparently have a damaging effect on the plasmalemma and possibly on other cell membranes with which the initial stages of TMV reproduction are associated. The development of the RNase damaging effect can be prevented by bivalent metal ions in the incubation medium, especially by calcium and manganese. The protective effect of cations is presumably caused not only by the charge, but by their steric configuration since K+ and Mg++ are ineffective in protecting the protoplasts.
Incidence and Control of Necrotic Leaf Mosaic Caused by Arabis Mosaic Virus in Lilium tigrinum splendens in the Netherlands
Authors: Asjes C. J. , Segers Louise Ch. 
Published: May 2008

AbstractNecrotic mosaic on leaves and ring spots on bulb scales of Lilium tigrinum splendens, can be caused by arabis mosaic virus (AMV). Primarily infected bulbs can show spongy roots and large necrotic areas on creamy coloured bulb scales. Consecutive series of plants replanted for monthly periods in infested soil were mostly infected by AMV at a high rate (70%) throughout the year. Very low or undetectable numbers of Xiphinema diversicandatum, nematodes in soil dilution experiments infected lilies very efficiently (50–70 %). In general, soil disinfestation with dichloropropene, dazomet, methylbromide, and other disinfectants were variably fairly effective, particularly when yellow crocus among which couch was abundant, was previously grown for two years. The influx of AMV infected material into the soil was assumed to increase the number of AMV‐carrying nematodes, and may be one cause of the failure of soil disinfestation. A survey of AMV infested soil in lily‐growing regions in The Netherlands indicated its occurrence in a few fields only. Complex control measures applicable under growers' conditions, in addition to the variably effective soil disinfestation, are indicated.
Bestimmung pektolytischer Enzyme bei mehreren Schadpilzen von Citrusfrüchten
Authors: Rose W. , Knösel D. 
Published: May 2008

Abstract Characterization of pectolytic enzymes From several fungi causing post‐harvest decay of citrus fruits From culture filtrates of Penicillium digitatum Sacc., Trichoderma viride Penz., Phomopsis citri (Faw.) cf. Diaporthe citri (Faw.) Wolf, and Colletotrichum gloeosporioides Penz. endo‐polygalacturonase and endo‐polymethylgalacturonase have been isolated. Both enzymes were active under acid conditions only. The last named fungus additionally produced pectic acid‐transeliminase, the activity was found under alkaline conditions.
Helminthosporium maydis Suppresses Expression of Resistance to Helminthosporium carbonum in Corn
Authors: Pascholati S. F. , Nicholson R. L. 
Published: May 2008

AbstractInoculation of corn mesocotyls with Helminthosporium maydis (susceptible combination) at the same time or at intervals up to 45 h after inoculation with H. carbonum (resistant combination) suppressed the expression of resistance to H. carbonum. This occurred even when the ratio of H. carbonum to H. maydis spores was as much as 100:1. When inoculated at 60 h after H. carbonum, H. maydis was unable to suppress resistance expression and was also unable to establish a susceptible disease interaction.
Light Sensitivity of the Antagonism of Cladosporium Species to Races of Melampsora larici‐populina Kleb. on Cultivars of Populus×euramericana (Dode) Guinier
Authors: Sharma I. K. , Heather W. A. 
Published: May 2008

AbstractAntagonism of five species of Cladosporium to production of uredinia by three races of Melampsora larici‐populina on leaf disks of poplar (Populas × euramericana) was generally higher with races A and E but lower with race D, at high light intensity (400 μ Em−2s−1) than at low light intensity (100 μ Em−2s−1). Colonization by all species of Cladosporium, of the uredinia induced by the races on the cultivars, was higher at the low than at the high light intensity. The extent of reduction in colonization with increasing light intensity depended on the race, cultivar and species of Cladosporium involved. While the species of Cladosporium was the most important major factor affecting both uredinial production and colonization, race, cultivar, light intensity of incubation and species of Cladosporium interacted significantly to determine disease level (uredinial number) on the leaf disks and the percentage of these uredinia subsequently colonized by the Cladosporium spp.
Carbon Dioxide Exchange in an Incompatible Barley/Powdery Mildew Combination
Authors: Walters D. R. , Ayres P. G. 
Published: May 2008

AbstractCO2 exchanges in intact barley leaves were studied by infra red gas analysis after inoculation with an incompatible race of powdery mildew. Net photosynthesis was inhibited, and dark and photorespiration were stimulated, by inoculation. The increase in respiratory processes was approximately equal to the change in net photosynthesis indicating that CO2 fixation, “gross photosynthesis”, was unaffected by inoculation. It is concluded that changes in net photosynthesis may be the primary cause of the reduced quantity and quality of grain in incompatible barley/mildew combinations.
The Possible Role of Phenolic Compounds in Resistance of Horticultural Crops to Dematophora necatrix Hartig
Authors: Sztejnberg A. , Azaizia H. , Chet I. 
Published: May 2008

AbstractCrops e. g., pecan, persimmon and passionflower, which show resistance to the fungus Dematophora necatrix, the causal agent of white root rot disease, contain phenolic compounds which inhibit its growth. Roots of resistant crops contain higher concentrations of phenolic compounds than those of suceptible crops, e. g., apple, almond and peach.The fungus contains active polyphenoloxidase (PPO). The oxidation of phenols to quinones may decrease the inhibitory effect. Catechol, methylcatechol, hydroquinone and 8‐hydroxyquinoline significantly inhibited the growth of the fungus.In greenhouse experiments, seedlings were irrigated with, or dipped in, phenols. Catechol, methylcatechol and hydroquinone delayed the appearance of disease symptoms.
Wissadula Proliferation in Jamaica
Authors: Dabek A. J. , Waters H. , Lavin D. 
Published: May 2008

AbstractIn Jamaica, phloem‐restricted prokaryotes were found associated with a little leaf proliferation disease of Wissadula periplocifolia (L.) C. Presl. ex Thwaites. Electron microscopy of single ultrathin sections revealed circular, ovate and elongate profiles 120—500 nm in diameter/width and 125—4200 nm long. Most were bound by a double membrane and resembled the phloem‐restricted rickettsialike organisms associated with a small number of other plant diseases; others which were peripherally ill‐defined or without an obvious double membrane were indistinguishable from mycoplasmalike organisms. Further work is required to elucidate their taxonomic status and possible role in the aetiology of the disease. No potential aetiological agent was discovered for a symptomatologically similar disease of Abuliton hulseanum (Torr. & A. Gray) Torr. ex Chapm. which accurred intermixed with the Wissadula disease. The names Wissadula proliferation and Abutilon proliferation have been used to describe these newly recorded diseases.
Detection of a Luteovirus in Groundnut Rosette Diseased Groundnuts (Arachis hypogaea) by Enzyme‐linked Immunosorbent Assay and Immunoelectron Microscopy
Authors: Sylke Meyer R. Casper , Lesemann D.‐E. , Ramanan Rajeshwari D. V. D. Reddy , Misari S. M. , Subbarayudu S. S. 
Published: May 2008

AbstractIn groundnut rosette diseased groundnut plants collected near Zaria, Nigeria, a luteovirus was detected by ELISA and ISEM. In ELISA only beet western yellows virus antiserum reacted, while in ISEM luteovirus particles were trapped by antisera beet western yellows virus, potato leafroll virus, pea leafroll virus and barley yellow dwarf virus. The data are in agreement with the interpretation that the assistor of groundnut rosette virus is possibly a member of the luteovirus group.
Studies in Heterobasidiomycetes, Part 31*). On the Anther Smuts of Silene vuigaris (Moench) Garcke
Authors: Deml G. , Oberwinkler F. 
Published: May 2008

Abstract Microbotryum silenes‐inflatae (DC) G. Deml & Oberw. and Microbotryum violaceoirregulare (Brandenburger & Schwinn) G. Deml & Oberw., both parasitic in the anthers of Silene vulgaris (Moench) Garcke, are compared by their morphology, karyology, and some cultural characteristics.The infection of their hosts is similar in both species, but causes different sizes of the flowers and different color of the spore mass. The teliospore initials of that smuts are produced in dikaryotic sporogenous hyphae. During gelatinization of the hyphal coat, surface ornamentations on the teliospores are formed. Mature teliospores are monokaryotic, and presumably diploid, reticulate in Microbotryum silenes‐inflatae and echinulate in M. violaceo‐irregulare. Teliospores of both species germinate without a resting periode. Germination results in a commonly three‐celled promycelium, which in M. silenes‐inflatae separates from the producing teliospore, while in M. violaceo‐irregulare it remains on the teliospore during basidiospore formation. The basidiospores are monokaryotic and propagate by budding. Monokaryotic strains were isolated and characterized by standard yeast identification tests and by some enzymatic activities on solid media. While no differences in the enzymatic activities can be found, the species differ in their utilization of carbon sources.
Quantitative Studies of Resistance Induced By Avirulent Cultures of Erysiphe graminis f. sp. hordei in Barley
Authors: Chaudhary R. C. , Schwarzbach E. , Fischbeck G. 
Published: May 2008

AbstractQuantification of resistance induced by avirulent cultures of Erysiphe graminis f. sp. hordei against virulent cultures in barley was attempted. Four mildew cultures and 4 barley varieties with known genes of virulence and resistance respectively were used. Pre, post and simultaneous inoculation of leaves was done with avirulent and virulent cultures. Pre‐inoculation with avirulent cultures induced resistance in the host such that the pustule number and spore production by later inoculation of virulent cultures was reduced significantly. Once induced, such resistance was active up to 8 days. There was some indication of induced susceptibility if the inducing culture was characterized by medium virulence. Increase of inceulum density of the avirulent (inducer) culture increased the amount of induced resistance Further studies of the phenomenon of induced resistance are needed in relation to possible applications for disease control through inoculations. varietal mixtures and multilines.