摘要:

AbstractWe have localized the mRNA of the epidermal growth factor receptor (EGF‐receptor) in nuclei of A431 cells by non‐radioactive in situ hybridization at the light microscopical level using digoxigenin‐labelled DNA probes. Both formaldehyde and glutaraldehyde fixations were tested before the hybridization was performed. Glutaraldehyde, compared with formaldehyde fixation, gives a less diffuse hybridization signal, which is easier to localize. Therefore, glutaraldehyde was used as a fixative in the hybridization experiments. It is demonstrated that the mRNA of the EGF‐receptor is present in restricted domains mainly located around the nucleolus. This location of the EGF‐receptor mRNA was unaltered after extraction of chromatin. Therefore it is concluded that the messenger RNA of the EGF‐receptor is attached to the nuclear matrix. A possible biological role for the location of mRNA of the EGF‐receptor around the nucleolus

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1001

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe salivary gland cells of Calliphora vomitoria larvae initiate and complete their own destruction in a programmed manner at the onset of metamorphosis.On entering the post‐feeding period the larvae come to rest and the polytene salivary gland cells show a significant increase in DNA synthesis followed closely by a surge of mRNA synthesis accompanied by increasing protein production. During this prelude to cell death the new mRNA gives rise to at least 10 new proteins. The first new proteins having a MWt between 30 and 100kD appear by day 8 of the life‐cycle and a number persist until the advent of cell death on day 9. Other new proteins appear in a cascade of production during day 8 and in vitro translation of mRNA produced at this time shows a new 55kD protein appearing before cell destruction.Significantly no evidence of DNA degeneration or laddering associated with classical apoptosis was observed, on the contrary considerable DNA synthesis in the form of chromosomal endoduplication or "genomic amplification" was seen; selective gene expression being apparently controlled at translational level. Overall the results strongly suggest a synthetically mediated programmed cell death in the metamorphosing salivary glands of the blow‐fly which is distinct from apop

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1002

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn prophase I‐arrested surf clam oocytes, fertilization is the normal trigger for resumption of meiosis, first evidenced by germinal vesicle breakdown (GVBD). Various artificial agents are able to induce GVBD and most of them require the presence of external Ca2+to be efficient. One exception to this rule is the reported possibility of inducing GVBD by an hypertonic treatment, using high concentrations of glycerol, in the complete absence of external Ca2+. We have investigated the processes underling glycerol‐induced activation and found that, under this condition, GVBD shows very slow kinetics and is not followed by any normal subsequent steps of meiosis, such as formation of metaphase chromosomes or polar body extrusion. Glycerol‐activated oocytes do not show the normal response in protein synthesis but they undergo increased protein phosphorylation which is inhibited by 6‐dimethylaminopurine (6‐DMAP), which also inhibits GVBD. We conclude that the hypertonic treatment by glycerol, in the complete absence of external Ca2+, induces a partial program of activation through increased protein phosphorylation but that the normal full response requires an increased Ca2+influx as triggered by other well‐known artificial activa

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1003

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe interaction of low mobility group proteins (LMG), isolated from chromatin of pancreatic carcinoma cells (CAPAN‐2), with fragments of 5′‐flanking region of the antigen 17‐1A gene was studied by gel retardation assay. The LMG proteins, which formed complexes with DNA were extracted from the gels and identified by polyacrylamide gel electrophoresis under denaturing conditions. The proteins of Mw about 100, 60, 55 and 48 kDa, which formed specific complexes with fragments of 5′‐flanking region of the antigen 17‐1A gene, we

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1004

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe concerted action of TGF‐β and PDGF on a diploid human embryonic lung fibroblast cell strain (Flow 2002) grown in an homologous environment is investigated here. In sparse cultures, TGF‐β stimulates DNA synthesis over a broad concentration range (0.1‐10 ng/ml). Furthermore, it acts in synergism with PDGF, a phenomenon which persists also during in vitro aging of the cells. Preincubation of TGF‐β with the fibroblasts up to 12 hours reduces the subsequent PDGF binding to the cells, while prolonged preincubation restores PDGF binding to control levels. Finally, in cultures of higher cell densities, TGF‐β ceases to stimulate DNA synthesis, whereas PDGF continues even at cell confluency, retains its stimulatory activity suggesting different roles for the two growth factors during the wound he

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1005

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effect of hepatocyte growth factor/scatter factor (HGF/SF) on the proliferation of human skin fibroblasts was examined. At concentrations above 1.0 ng/ml, both native and recombinant human HGF/SF stimulated the DNA synthesis determined by [3H]thymidine incorporation, which was completely inhibited by an anti‐human HGF/SF monoclonal antibody. The maximal DNA synthesis in the treated cells was nearly twice that in untreated cells. HGF/SF also caused an increase in the labelling index, DNA content and cell number. The effect of HGF/SF was more than additive to the maximal effect of insulin and epidermal growth factor, other mitogens for the fibroblasts. These results indicate that human skin fibroblasts are sensitive to the mitogenic action of HGF/S

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1006

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractTreatment of cultured rat osteoblasts with staurosporine caused a rapid outgrowth of long slender cellular processes and the formation of stellate cells. The number of stellate cells increased with higher concentrations of and longer incubation with staurosporine. Scanning electron microscopy (SEM) revealed that the smooth surface of control polygonal cells became ruffled with many long slender cellular processes, thus increasing the cell surface area. Transmission electron microscopy (TEM) of the stellate cells showed a rich accumulation of large lipid droplets in the cytoplasm. Some lipid droplets had coalesced under the cytoplasmic membrane. We suggest that staurosporine has an effect on the differentiation of cultured rat osteoblasts.

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1007

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn the present study the cellular distribution of the inducible (hsp72) and constitutive (hsc73) forms of human 70 kD heat shock protein was evaluated. A weak reactivity of the anti‐hsp72/hsc73 MoAb was found in the cytoplasm of the unstressed human epidermal cells, while stressed cells showed an enhanced reactivity at the cytoplasmic level and the expression of the molecules on the cell surface. Moreover, the antigenic properties of the two proteins were investigated by sequence analysis. Our findings provided evidence for at least three regions in the hsp72 which can be considered good candidates to represent T‐immunogenic antigens. This data as well as the cell surface localization of the hsp72 could suggest an antigenic role of the hs

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1008

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractFlash frozen samples of normal human blood were cryosectioned and cryodried for electron probe x‐ray microanalysis of the concentration of ions and elements in individual erythrocytes (RBCs). The data (expressed in mM/kg dry weight) demonstrated a systematic pattern of variation between the concentration of ions and elements in the RBCs. Specifically as K+and Cl decreased in concentration, Ca2+and sulfur increased in concentration. Phosphorous, Na+and Mg2+did not demonstrate a significant pattern of change. These findings are related to the dehydration and to the volume decrease that accompanies senescence of the RB

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1009

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA monoclonal antibody raised against and specific for cytochrome P‐450 isoenzyme CYP4A1 was used to investigate the subcellular distribution of this enzyme in the liver, kidney and ileum of nafenopin treated rats by means of immunoelectron microscopy. In the liver and kidney, labelling was restricted to peroxisomes and mitochondria of hepatocytes and proximal tubular epithelial cells whereas in ileum, immunolabelling was exclusively detected in mitochondria of absorptive cell

ISSN:1065-6995    

DOI:10.1006/cbir.1993.1010

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY