Demonstration of components of serum-free culture medium effecting maximum in vitro expression of mouse mammary tumor virus

Nagle, Stanley C.; Fine, David H.

doi:10.1007/bf02618226

Cited by 7 publications

(1 citation statement)

References 39 publications

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“…Such cells (at an estimated frequency of 33% of the total B cells in a field) commonly would contain 1-4 type Aparticles; these structures were always observed within distended profiles of RER and were detected with equal frequency in control and m db/m db B cells. Since glucocorticoids have been shown to enhance both C-particle [12] and B-particle [13,26] induction in cell cultures, hydrocortisone hemisuccinate (10 .5 mol/1) or dexamethasone (10 .6 mol/1) was included in high glucose DMEM in an attempt to increase the numbers of A-particles per cell section. Such an effect on particle number was not observed at the ultrastructural level.…”

Section: Viral Expression In Cell Culturementioning

confidence: 99%

Intracisternal A-particles in genetically diabetic mice: Identification in pancreas and induction in cultured beta cells

Leiter

Bedigian

1979

Diabetologia

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Sucrose density gradient analysis of purified pancreatic homogenates from glycaemic C57BL/Ks diabetes (db/db) mice and their normoglycaemic controls have revealed the presence in the diabetics of increased Mg++-dependent RNA-directed DNA polymerase activity sedimenting with a density of approximately 1.21 g/cm3. Electron microscopy revealed that this fraction contained typical intracisternal A-particles. Purified cultures of pancreatic islet cells 4--7 day old postnatal "misty diabetic" mice and normal siblings were established and then maintained in Eagle's minimal essential medium without serum. Under these conditions, the presence of intracisternal A-particles in beta cells of both mutant and control genotypes was very rare. No change in numbers of intracisternal A-particles was seen after 2--4 days of incubation in Dulbecco's-modified minimal essential medium containing 5.5 mmol/l glucose. However, when the glucose concentration of Dulbecco's medium was elevated to 16.5 mmol/l, ultrastructural changes specific to the beta cell population occurred that were reminiscent of those alterations observed in situ. Intracisternal A-particles were commonly seen in cultured beta cells showing hypersecretion-stress morphology. Since equal numbers of intracisternal A-particles were present in cultured beta cells from normal and mutant mice, it was concluded that the db gene itself was not required for intracisternal A-particle expression. The cell culture results suggest that elevated intracisternal A-particle activity observed in vivo may be produced directly or indirectly by the ambient high blood glucose levels characteristic of this mutant.

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Section: Viral Expression In Cell Culturementioning

confidence: 99%

Intracisternal A-particles in genetically diabetic mice: Identification in pancreas and induction in cultured beta cells

Leiter

Bedigian

1979

Diabetologia

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Status and developments of animal cell technology using suspension culture techniques

Katinger¹,

Scheirer²

1982

Acta Biotechnologica

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I n this review the state of the art in animal cell technology, using suspension culture techniques is updated as far as the end of 1980. We have tried to discuss, on a broad basis, the current status and potential developements of both, the purely biological and the biochemical engineering aspects which may be important to improve the performance and design of animal cell technologies. The process economics could be considerably improved by the use of transformed animal cell substrates, the use of cheaper cultivation media and by methodological and engineering means. Most of these aspects are in the state of rcalization. Nevertheless, for a great variety of biological active sub-. stances which do not require coor posttranslntional processing, recombinant DNA-techniques (e.g. genetic engineering) are a promising alternative for the production of animal cell derived substances. Zusammenfassung Mit diesem Beitrag wird versucht, eine Obersicht uber den Entwicklungsstand der ,,Technologic mit tierischen Zellen" (begrenzt auf Verfahren mit Suspensionskulturen) mit Status Ende 1980 zu vermitteln. Wir haben dabei versucht, zur Zeit schon ctablierte Verfahren wie auch potentielle Entwicklungsmoglichkeiten dieser Technologie aufzuzeigen und zu diskutieren. Es wurden hierbei sowohl die rein biologischen Aspekte somie die sich daraus ergebenden Konsequenzen fiir die biologische Verfahrenstechnik im Rinblick auf die Verfahrensabwicklung und Moglichkeiten der ProzeBverbessemg analysiert. Die Technologie mit tierischen Zellen kann durch den vermehrten Einsatz transformierter Zellen als Produktionsvehikel, die Entwicklung billiger Niihrmedien und die Verbesserung der Massenkultivierung auf methodischer wie verfahrenstechnischer Ebeno noch wesentlich verbessert werden. Viele der genannten Verbesserungsmoglichkeiten sind im Entwicklungsstadium. Fiir die Produktion einer Reihe von bioaktiven Wirkstoffen am tierischen Zellen, welche fur ihre Biospthese cooder posttranslationale Modifikationen nicht erfordern, sehen wir die bessere Alternative in der DNA-Technologie (z. B. mittels der Gentechnik). PrefaceThis review article is the full text of an invited lecture held a t the "Chemap Cell Culture Symposium", sponsored and organized by the Chemap AG in January 1980. The state of the art in animal cell technology, using suspension culture techniques has been updated as far as the end of 1980. It is mainly addressed to biotechnologists who are ,,non-specialists" in the field of animal cell technology.

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Hormone Regulation of Bovine Leukemia Virus via the Long Terminal Repeat

Niermann

Buehring

1997

Virology

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The hormone regulation of viruses has been of great interest since the discovery of glucocorticoid stimulation of mouse mammary tumor virus via a hormone response element in the viral long terminal repeat (LTR) promoter region. This report describes the investigation of the hormone responsiveness of bovine leukemia virus (BLV), an oncogenic retrovirus that infects dairy and beef cattle worldwide. It is a member of the human T cell leukemia (HTLV)/BLV group of retroviruses, which encode a protein, Tax, that is essential for regulating transcription of their own proviruses and for transforming host cells. We investigated the responsiveness of BLV to the hormones 17 beta-estradiol, progesterone, prolactin, insulin, and dexamethasone, a potent glucocorticoid. Only dexamethasone, in combination with insulin or insulin/prolactin, consistently stimulated BLV expression, as measured by reverse transcriptase activity, RNA blot hybridization (Northern blots), and CAT (chloramphenicol acetyltransferase) reporter assays of cell lines transiently or stably transfected with the BLV LTR. This effect required the presence of glucocorticoid receptors and Tax. This is the first report of hormone responsiveness in a virus of the HTLV/BLV group.

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Demonstration of components of serum-free culture medium effecting maximum in vitro expression of mouse mammary tumor virus

Cited by 7 publications

References 39 publications

Intracisternal A-particles in genetically diabetic mice: Identification in pancreas and induction in cultured beta cells

Intracisternal A-particles in genetically diabetic mice: Identification in pancreas and induction in cultured beta cells

Status and developments of animal cell technology using suspension culture techniques

Hormone Regulation of Bovine Leukemia Virus via the Long Terminal Repeat

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