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At least 199 records · Page 11Linked to original sources
PubMed1999

Immunization of mice with live oral vaccine based on a Salmonella enterica (sv Typhimurium) aroA strain expressing the Escherichia coli O111 O antigen.

Shiga toxin-producing Escherichia coli strains of serogroup O111 are the most frequently isolated non-O157 strains causing outbreaks of gastroenteritis with haemolytic uraemic syndrome (HUS). O antigen is a major antigen in Gram-negative bacteria, and it has been shown that O111 is a protective antigen. Attenuated Salmonella enterica sv Typhimurium aroA strain STM-1 was used as a live carrier to express the E. coli O111 O antigen. Mice immunized intraperitoneally produced serum immunoglobulin G, and mice immunized orally produced serum immunoglobulin G and secretory immunoglobulin A in the intestine against E. coli O111 cells as determined by enzyme-linked immunosorbent assays.

Administration, Oral↗
PubMed1976

Ultrastructural and cytochemical features of SV 40 transformed hypothalamic cell lines.

A continuous cell line was previously obtained by Simian Virus (SV) 40 transformation of primary cultures of dissociated mouse fetal hypothalami. One clone from this cell line has been previously shown to possess some of the ultrastructural features, immunological properties and synthesizing capacities of magnocellular hypothalamic neurons which secrete vasopressin and neurophysins. The present paper reports on the morphological characterization of 14 other clones or subclones of the original cell line, using the following criteria: phase contrast microscopy, electron microscopy, Gomori's aldehyde fuchsin staining, cytochemical detection of beta-glucuronidase, immunochemical staining with antisera against bovine neurophysin I, bovine neurophysin II, lys-vasopressin, oxytocin, LH-RH and TRH. The results allowed the conclusion that the clones as well as the subclones can be distributed into two groups: 1) neurosecretory neurons which all possess several of the ultrastructural and cytochemical features of the neurophysin-vasopressin synthesizing clone, and 2) primitive nerve cells which are devoid of such features but display numerous bundles of filaments. In addition some clones were found to display intermediate features between groups 1 and 2. A similar diversity was observed within clones of the original strain and subclones of a neurosecretory clone. It is suggested that the primitive clones could represent precursors of the neurosecretory clones.

Animals↗
PubMed1975

Stability of X chromosomal inactivation in human somatic cells transformed by SV-40.

Clones of fibroblasts from a G6PD A heterozygote transformed with SV-40 did not express the G6PD silent allele in the transformed heteroploid cultures. In addition, transformed fibroblasts from a woman heterozygous for both G6PD A and HGPRT deficiency, subjected to selective pressure, did not reveal a single cell expressing either silent allele. Since the incidence of sex chromatin was significantly lower in these cells after transformation, it is likely that the loss of sex chromatin reflects the loss of the inactive X-chromosome at an early stage following transformation.

Aneuploidy↗
PubMed1977

Studies of the UV-sensitivity of virus-specific RNA synthesis in cells infected or transformed by adenovirus 5 and SV 40.

The effect of UV-irradiation on host and virus-specific RNA synthesis in cells infected or transformed by tumor viruses (Ad 5 and SV 40) was studied. It was found that the synthesis of host and Ad 5 RNA in infected KB cells was almost euqally inhibited upon UV-irradiation; the transcription of the EcoRI produced fragements--fragment B was inhibited to a greater extent than fragment A, suggesting that the transcription of the whole Ad 5 genome starts from the left side. The transcription of viral sequences in transformed cells, on the other hand, was more resistant to UV-irradiation than the transcription of the host ones. The results obtained suggest that the small size of the virus transcriptions, or their location at the beginning of large host transcriptions, may be responsible for the observed data.

Adenoviridae↗
PubMed1978

Location of the cleavage sites on the SV 40 DNA map produced by the restriction endonucleases Pst 1 and Bam 1.

Restriction endonucleases from Providencia stuartii (Pst 1) and Bacillus amyloliquefaciens H (Bam 1) cleave SV 40 DNA at two and one specific sites, respectively. Using EcoRI and Hind III endonuclease restriction sites as reference, the two Pst I sites were mapped at 0.050; 0.265 and the Bam I site was mapped at 0.170 of the genome length, clockwise, from the single EcoRI cleavage site.

DNA Restriction Enzymes↗
PubMed1989

Gangliosides in SV-40-transformed cells derived from Tay-Sachs disease fetal brain.

A human glial brain cell line derived from a Tay-Sachs disease fetal cerebellum was transformed with SV-40 virus in order to obtain a transformed brain cell line which reflected the characteristics of the disease. It was shown that the transformed TSD cell line maintained an elevated level of GM2 which was similar to that shown by the nontransformed precursor. In addition, the TSD transformed line lacked hexosaminidase A.

Cerebellum↗
PubMed1983

Hamster endogenous retrovirus (HaER) isolated from SV-40 induced tumor cells.

A hamster cell line obtained from a secondary transplanted SV-40-induced tumor was found to spontaneously release type C virus particles. The particles possessed all biochemical features characteristic of retroviruses and induced syncytium formation in XC cells but were not oncogenic for hamsters. Nucleic acid hybridization assays demonstrated that the isolated virus was an endogenous retrovirus of hamster, lacking sequence homology with mouse and other animal species.

Animals↗
PubMed1978

Immunocytochemical evidence of SV 40-related T antigen in two human brain tumours of ependymal origin.

A series of thirty-time human brain tumours has been screened for the presence or absence of SV 40-related T antigen by the direct and indirect immunoperoxidase techniques. Two tumours (an ependymoma and a choroid plexus papilloma) of ependymal origin revealed markedly positive nuclear staining for T antigen both in in vivo and in vitro. The possible viral etiology of these human brain tumours is discussed in relation to recent human papovavirus isolates.

Animals↗
PubMed1975

1-H and 13-C nuclear magnetic resonance spectra of the lipids in normal and SV 40 virus-transformed hamster embryo fibroblast membranes.

Well resolved 1-H and 13-C NMR spectra were obtained with normal and SV 40-transformed cell membranes. Estimation of the ratio of 13-CT2 values of the normal to transformed cell membranes showed an increased intermolecular motion in the transformed cell membranes. The temperature dependence of the (CH2) line in the 1-H spectra in the temperature range 298-343 degrees K shows an activation energy for the lateral diffusion of the fluid phospholipid regions in the normal cell membranes while the transformed ones show practically no temperature dependence in this temperature range. The fluidity of the phospholipid region in the transformed cell membrane seems to be significantly higher than that observed in the normal cell material. These data support and extend the findings concerning the mobility of the concanavalin A binding/agglutinating sites on the surface of normal and virus-transformed cells and suggest further approaches to the study of the membrane alterations in tumor cells.

Animals↗
PubMed1975

Stimulated phosphorylation of non-histone phosphoproteins in SV-40 transformed WI-38 human diploid fibroblasts.

Because the phosphorylation of non-histone proteins has been suggested to play a role in the regulation of eukaryotic gene transcription, we have compared the phosphorylation of these proteins in normal and SV-40 transformed WI-38 human diploid fibroblasts. The rate of phosphorylation was found to be roughly ten-fold higher in the transformed cells, and this striking difference could not be accounted for by either an increased rate of phosphate transport or by the synthesis of new species of non-histone proteins which subsequently become phosphorylated. To our knowledge this is the most dramatic alteration in non-histone protein phosphorylation ever described, and therefore may have important implications for our understanding of malignant transformation.

Biological Transport↗
PubMed1991

Hepatocyte growth factor/hepatopoietin A stimulates the growth of rat kidney proximal tubule epithelial cells (RPTE), rat nonparenchymal liver cells, human melanoma cells, mouse keratinocytes and stimulates anchorage-independent growth of SV-40 transformed RPTE.

Hepatocyte growth factor/hepatopoietin A is a mitogen for primary hepatocytes and may mediate regeneration after liver damage. To date, the activity of this novel factor has been restricted to hepatocytes. We now show that the factor is also a mitogen for a number of primary epithelial cells but is inactive with human foreskin fibroblasts, human endothelial cells and HEP3B cells. The factor also substitutes for HBGF-2 (basic FGF) in stimulating the anchorage-independent growth of SV-40 transformed rat kidney epithelial cells. Therefore, hepatocyte growth factor/hepatopoietin A appears to act on a variety of epithelial, but not mesenchymal, cells which respond to HBGFs.

Animals↗
PubMed1991

Eye pathology in transgenic mice carrying a MSV-SV 40 large T-construct.

Several lines of transgenic mice carrying a transgene construct consisting of the regulatory enhancer element of the Moloney murine sarcoma virus and the Simian virus 40 genome coding for the SV 40 promoter and the large T antigen were established. We describe several abnormalities found in the eyes of transgenic animals of which heritable cataract formation, probably due to disturbances in primary lens fibre differentiation, showed a close correlation to large T antigen expression. Additionally, lenticonus anterior, retinal dysplasia and one case of malignant transformation of lens epithelium were found. The introduction of the deleted MSV-enhancer linked to the large T coding region led to less severe postnatally occurring cataracts. Thus, the partial deletion of the MSV enhancer resulted in differences in the degree of severity of lens disturbances. However, tissue specificity remained constant. Our results indicate that large T antigen seems to play an important role in cataract formation but not in the pathogenesis of retinal dysplasia.

Animals↗
PubMed1990

Secretion and intracellular degradation of collagen in cultures of normal and SV-40-transformed human fibroblasts.

With a pulse-chase technique, secretion and intracellular degradation of collagen were investigated in human cultured normal and SV-40-transformed fibroblasts. Normal cells at a proliferative phase of growth secreted collagen more actively than the stationary phase (resting) cells. Transformed fibroblasts secreted protein at a lower rate than both normal cell types. Resting and dividing normal cells displayed no differences in the rates of intracellular collagen degradation at the various stages of the chase period. Transformed cells did not differ from the normal ones in collagen degradation rates at the first hour of the chase period while at later times in the chase period, the total amount of degraded collagen was reduced by 20-30% in the transformed vs normal cultures. The data are discussed in the view of possible relations between the various mechanisms of intracellular transport and degradation of collagen.

Cell Division↗
PubMed1995

Hemostatic properties of the SV-40 transfected human microvascular endothelial cell line (HMEC-1). A representative in vitro model for microvascular endothelium.

HMEC-1 is a SV-40T transfected human microvascular endothelial cell line that constitutively expresses RNA transcripts for plasminogen activator inhibitor 1 (PAI-1), tissue-type plasminogen activator (t-PA), protein S (PS), von Willebrand factor (vWF), and thrombomodulin. Tissue factor (TF) can be induced in response to stimulation with tumor necrosis factor alpha (TNF-alpha), interleukin-1 alpha (IL-1alpha) and phorbol 12-myristate 13-acetate (PMA). Proteins corresponding to PAI-1, t-PA, protein S and vWF genes were constitutively released in the culture supernatant. This cell line is a model that will be useful to investigate coagulation/fibrinolytic properties of microvascular endothelium.

Basal Metabolism↗
PubMed1983

Fetal and maternal immunologic manifestations of intrauterine Adenovirus SV-20 infection.

Rhesus monkey fetuses of either immune or nonimmune dams were inoculated in utero with Adenovirus SV-20 (AdSV-20), a virus capable of inducing fetal pneumonia, and studied immunologically at various intervals. AdSV-20 infection at 90-100 days gestational age resulted in absolute lymphopenia in a few fetuses, reduced numbers of peripheral blood lymphocytes (PBL) which formed rosettes with sheep erythrocytes (ERL) and reduced complement-receptor lymphocytes (CRL) in a majority, while Fc fragment-receptor lymphocytes (FcRL) were occasionally increased. There was a tendency for depression of ERL and CRL early in infection of 120-130-day fetuses, followed by stimulation of these populations and FcRL in later phases. Maternal immunity did not protect against these effects of AdSV-20 infection in fetuses. Immune and nonimmune dams were spared adverse clinical effects and had no changes in lymphoid cell populations following inoculation of their fetuses. Despite precocious production of circulating IgM, fetuses of nonimmune dams had little or no demonstrable anti-AdSV-20 serum neutralizing (SN) antibody, indicating that the ability to develop an effective immune response was suppressed or had not been acquired at the gestational ages studied. Nonimmune dams displayed little evidence of seroconversion following inoculation of their fetuses with AdSV-20, except in those dams whose fetuses died in utero, whereby there was a significant antibody response. SN antibody titers of immune dams were not boostered substantially subsequent to inoculation of their fetuses, and fetal SN titers were lower than maternal titers, suggesting absence of an active fetal antibody response in this group also. Direct inoculation of AdSV-20 into 90-130-day rhesus monkey fetuses provided a model system for immunologic study of fetal infection, probably involving complex fetal-maternal interactions, in a situation where the infected, viable fetus and its dam appeared to be microbiologically isolated from one another.

Adenoviruses, Simian↗
PubMed1984

Evaluations of wasted mouse fibroblasts and SV-40 transformed human fibroblasts as models of ataxia telangiectasia in vitro.

Fibroblast cultures from wasted mice have been derived and the responses of these cultures to bleomycin treatment or gamma-irradiation have been examined. No differences were observed between wasted fibroblasts and littermate controls in the post-treatment inhibition of DNA replication. In contrast, a human SV-40 transformed ataxia telangiectasia fibroblast line mimicked the abnormal response of primary ataxia telangiectasia fibroblasts to gamma-rays or bleomycin and thus appears to be a useful in vitro model of ataxia telangiectasia.

Animals↗
PubMed1982

Conditions for sliding of nucleosomes along DNA: SV 40 minichromosomes.

'Sliding' of nucleosomes along DNA under nearly physiological conditions was studied using treatment of SV 40 minichromosomes with the single-cut restriction endonucleases EcoRI and BamHI. Each enzyme can convert no more than 20-25% of the circular DNA molecules of minichromosomes into the linear form irrespective of the presence of histone H1. This suggests absence of the nucleosomes lateral migration (sliding) along DNa at least in the vicinity of the restriction endonucleases cleavage sites during several hours of incubation. The sites available for EcoRI and BamHI in minichromosomes seem to be located predominantly in the spacer DNA regions of nucleosomes. Introduction of only one double-strand (but not single-strand) break into the DNA of minichromosomes stripped of histone H1 is sufficient to induce redistribution of the nucleosome core particles due to their sliding along DNA. Thus, sliding of the nucleosome core particles can be induced under physiological conditions by rather low energy expenditures.

Animals↗