摘要:

AbstractThe 16 kD subunit of vacuolar H+‐ATPase (V‐ATPase) is essential for pumping protons into intracellular organella. Northern blot analysis revealed that the 16 kD subunit of V‐ATPase is abundantly expressed in rat brain, and that the amount of transcripts is higher in the postnatal 15 days than in the adult age. On in situ hybridization, the mRNA signal for 16 kD subunit of V‐ATPase was detected widely over the brain tissues of both adult and postnatal rats, with higher intensity in most of the gray matters located in the cerebellar cortex, hippocampus, thalamic nuclei, pontin nuclei, and olfactory bulb. In contrast, the signal in the cerebral cortex was preferentially enriched in the surface layers in the postnatal 10 days but was distributed diffusely and weakly over the entire layers thereafter. In all regions of brain, the mRNA signal was located predominantly in the neurons rather than in the glial com

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1001

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA new cell line was established from the bone marrow of a patient with chronic myeloid leukemia. The cells were attributed an intermediate myeloid phenotype on the basis of their cytochemical features and membrane antigen expression. These cells respond to both chemical and physiological activators of the signal transduction pathways with growth arrest and phenotype changes. Macrophage maturation can be induced in a fraction of the cells by gamma‐interferon (γ‐IFN). Cells are however recruited again into the cell cycle by recultivation in γ‐IFN‐free medium: variants unresponsive to γ‐IFN, and others which show either reversible or irreversible differentiation were isolated from the original cell line by cloning and sib‐selection. These clones can be used to investigate the relationship between γ‐IFN response pathways and c

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1002

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractFollowing exposure of CHO‐K1 cells to137Cs irradiation at doses up to 20Gy, a delay in G2was observed to occur in cells permitted to divide normally, while cells induced to become giants by means of cytochalasin B demonstrated a minimal delay in the transition 2C–8C suggesting that the inhibition of cytokinesis results in modification of one or more cell cycle checkpoints. We postulate that this may occur as a consequence of damage tolerance, or by a feedback loop resulting from the reorganisation of the cytoskeleton that precludes cytokine

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1003

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractX‐ray microanalysis was used to detect elemental changes in the insulin‐producing tumor cell‐line RINm5F. To improve discrimination between mobile ions and ions bound to macromolecules a new approach was employed, consisting of multivariate statistical analysis of correlations between the concentrations of Na, Mg, P, S, Cl, K, and Ca. RINm5F cells, cultured on Formvar‐coated titanium grids, were stimulated with high K+or ATP, that are both known to stimulate insulin release. The buffers used contained Ca2+or one of the Ca2+‐analogues Sr2+and Ba2+, to represent Ca2+uptake in response to stimulation. After stimulation the cells were shock‐frozen and freeze‐dried overnight. Incubation for 10‐20 seconds in a Ca2+‐containing buffer did not significantly affect elemental composition, whereas cellular Mg, P and K decreased in a Sr2+‐containing buffer. Depolarization with high K+concentration caused an increase in the cellular Na content, both in Ca2+‐ and Sr2+‐containing buffers, but not in the buffer where Ca2+had been replaced by Ba2+. X‐ray microanalysis is useful for detection of elemental changes subsequent to stimulation of cultured cells. Moreover, multivariate statistical analysis strengthens the idea that stimulation of RINm5F cells causes redistribution of ions possibly due to changes in the state of binding of some elem

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1004

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have studied the nature of P‐glycoprotein gene transcripts in multidrug resistant Chinese hamster ovary cell lines selected in vincristine. Using a novel,35S based, reverse transcription polymerase chain reaction assay, we have shown that there is a considerable increase in the level of pgp2 gene transcripts, with levels rising to a hundred fold those observed in sensitive control cells. The level of pgp1 gene transcripts was raised five fold. The levels of pgp3 gene transcripts were close to the limits of detection by the assay, but were increased in the more highly resistant cell lines. An increase in the size of the P‐glycoprotein gene transcript was also observed in some of the resistant cell li

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1005

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractPrevious work on five cell types isolated from the bovine corpus luteum showed that the mass of acetylated microtubules (acet‐MTs) in interphase differed. Endothelial cells, termed type 3, showed few acet‐MTs, whereas the interphase cytoskeleton of granulosal‐like cells, termed type 5, was rich in acet‐MTs. In the present study, these cultured cells were used to determine whether the degree of α‐tubulin acetylation in interphase had consequences on mitosis. To this end, the distribution of acet‐MTs was determined throughout the cell cycle using a monoclonal antibody, 6‐11B‐1, directed against acetylated α‐tubulin. For comparison, tyrosinated MTs were visualized with another monoclonal antibody, YL1/2, detecting tyrosinated α‐tubulin. Although the amount of acet‐MTs in interphase differed significantly between both cell types, major differences in the appearance of acet‐MTs during mitosis were only apparent in prophase and during transition from late telophase to interphase. Thus, irrespective of different α‐tubulin acetylation in interphase, spindle structure is uniform. Since acetylation of α‐tubulin is believed to indicate the presence of relatively stable MTs, we conclude that MT dynamics is differently controlled in interphase and mitosis. Thereby interphase cells are able to carry out functions which involve stable MTs and the cells progress through mitosis in

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1006

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe metabolism of [3H]labelled N‐Nitrosonornicotine a major constituent of the class of Tobacco Specific Nitrosamines was studied in adult and fetal human oesophageal cultures. The metabolites were separated by HPLC and were identified when compared to the standards as OH‐acid from 5′hydroxylation, NNN‐1‐N‐oxide formed via the pyridine N‐oxidation pathway and Keto acid from 2′hydroxylation in both the adult and fetal cultures. These results indicate that hydroxylation which leads to electrophilic diazohyroxides is the major pathway of NNN metabolism in cultured human oesophagus. In the adult cultures levels of metabolites formed were 20.32 pmoles/μg DNA of OH acid 11.08pmoles/μg DNA of NNN‐1‐N‐oxide and 7.67pmoles/μg DNA of Keto acid. In the fetal cultures levels were 10.85pmoles/μg DNA of OH acid, 9.40pmoles/μg DNA of NNN‐1‐N‐oxide and 7.91pmoles/μg DNA of Keto acid. These results indicate that α‐hydroxylation is the key step in the metabolic a

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1007

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractWe studied the effect of feeder cells (fibroblasts) and a mixture of the extracellular matrix components, Matrigel, on spreading and cytoskeleton organization of newborn rat keratinocytes (REK). REK formed lamellipodia on being plated together with feeder cells and on the Matrigel as a substrate whereas the same REK plated alone on a plastic surface formed filopodia. REK lamellipodia formation in co‐cultures depended on the fibroblast addition time. Although conditioned medium from fibroblast cultures was not enough to induce lamellipodia, the extracellular matrix left after fibroblast removal was as effective as Matrigel. Our results indicate that lamellipodia formation seems to depend on the factor(s) secreted by fibroblasts and associated with the extracellular matri

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1008

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe control of amino acid and purine biosynthesis in the yeast Saccharomyces cerevisiae is mediated by the transcriptional activator GCN4. We previously identified the presence of two putative GCN4 responsive elements (GCREs) in the promoter sequence of the Candida albicans ARO3 gene, which encodes an enzyme in the aromatic amino acid pathway. We now show that amino acid deprivation results in a dramatic rise in the steady‐state level of ARO3‐specific mRNA, indicative of a GCN‐like pathway in C. alb

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1009

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractBatten Disease is a lysosomal storage disease in which the major component that accumulates is subunit 9 of mitochondrial ATP synthase. Whether or not fibroblasts in culture exhibit this phenotype is controversial. We show that fibroblasts from a human Batten Disease patient and from a mouse model of this disease exhibit autofluorescent inclusion bodies. We also demonstrate that levels of ATP synthase subunit 9 are elevated in these diseased fibroblasts when compared to control cells. However, the exact growth state of the human fibroblasts was critical, and this factor probably accounts for discrepencies in the literature.

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1010

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY