Colchicine-induced resistance to antibiotic and amino-acid analogue in plant cell cultures.

Colchicine-resistant plant cell strains have been isolated from cell suspensions of carrot and sycamore. In the same way as colchicine-resistant animal cell strains, they show an increased resistance towards streptomycin and N-methylalanine. Cultivation under non selective conditions leads to a slow progressive loss of the resistance.     

Effect of L-amino-ethyl-cysteine,a sulfur analogue of L-lysine,on virus miltiplication in mammalian cell cultures

Summary L-amino-ethyl-cysteine clearly inhibits replication of Mengovirus; another RNA-virus (vesicular stomatitis virus) is completely insensitive. Protein synthesis is not impaired, but no active viral RNA-polymerase is detected.This work was partly supported by grant No. 73.01407.44 115.0107 of Consiglio Nazionale delle Ricerche, Roma, Italy. The technical collaboration of P. Meo and G. Conciatori is gratefully acknowledged.     

Induced radiation resistance in cell cultures of Chinese hamster cells: induction and manner of resistance (author's transl)]

Mutations-induction followed by selection is a suitable method for developing a cell line with resistance to low doses of X-rays. In comparison with the original cell line, the derived resistant line is characterized by an enhanced variability of the chromosome number, and no higher level of cellular repair, limited to the two repair types described.     

Toxicity of rabbit anti-dog lymphocyte serum to human cell cultures

Zusammenfassung Die Kombination von Kaninchen Anti-Hund Lymphozytenserum und Kaninchen Komplement war für menschliche Blutzellen in in-vitro-Kultur sowie für. Blutlymphozyten von Patienten mit chronischer lymphatischer Leukämie toxisch.     

Inhibition of cell division in mammalian cell cultures by hypertonic medium

Résumé L'arrêt de la métaphase se produit dans les cellules de HeLa S-3 au contact d'un milieu de tonicité accrue (>165 mM). L'accumulation optimale intervient à 277 mM lorsque du NaCl a été utilisé pour augmenter l'influence du milieu. Les effets de l'usage d'autres sels et d'autres types de cellules sont décrits. La dilution du milieu à 165 mM donne lieu à un arrêt synchrone du processus de la mitose dans les cellules et assure la conservation d'un bon synchronisme au cours de la division cellulaire suivante.     

A rapid microtechnique for incorporation studies in cell cultures

Zusammenfassung Eine Methode zur bequemen Messung radioaktiver Vorläufer in Monolayer-Zellkulturen wird beschrieben. Die auf flexiblen Plastikkulturplatten (z. B. Linbro FB 48-TC) in zahlreichen Einzelkulturen gezüchteten, markierten, extrahierten und getrockneten Monolayer-Kulturen können direkt (beispielsweise mit einer Schere) in Zählgläschen für die Szintillations-messung eingeschnitten werden.     

Molecular weight of virus-induced tortoise interferon in cell cultures

Zusammenfassung Das Molekulargewicht des Interferons, durch Selmiki Forest Virus in Zellkulturen von Schildkrötenniere induziert, wurde mittel Gelchromatographie mit Sephadex G-100 bestimmt und es ergab sich ein Wert von 33,500.     

Adenylate cyclase activation by trypsin in KB cell cultures

Summary Trypsin commonly used for cell dispersion increases adenylate cyclase activity of KB cells. It acts on catalytic receptors, since the apparent K_m for ATP is lowered, and it alters the dependence of adenylate cyclase on Mg⁺⁺ ions.     

Transfer of R-factor mediated aminoglycoside antibiotic resistance in the allantoic cavity of chick embryos

Zusammenfassung Die Allantoishöhle von 8 Tage alten Hühnerembryonen erwies sich als geeignet für die in vivo-Übertragung der Aminoglykosid-Antibiotika-Resistenz der klinisch isolierten StämmeE. coli 1531 undK. pneumoniae 829 auf den RezipientenE. coli K-12, Stamm 1485.     

Role of Golgi vesicles in plant cell elongation

Resumen La rápida elongación de las células durante la diferenciación se debe, entre otros motivos, a un incremento de la membrana envolvente; este incremento es originado por el aporte de vesículas del aparato de Golgi cuyas membranas coalecen con el plasmalema y su contenido se deposita externamente junto al material amorfo de la membrana.     

Regulation of lymphokine production in peripheral blood mononuclear cell cultures

An increase in the production of macrophage migration inhibitory factor, chemotactic factor for neutrophils, and skin reactive factor, was observed in lymphocyte cultures if the cells were allowed to age in culture for 24 h. The increased lymphokine production was reduced by adding concanavalin A-stimulated and mitomycin C-treated suppressor cells. It is suggested that the lymphokine production could be regulated by suppressive mononuclear cells.     

Regulation of lymphokine production in peripheral blood mononuclear cell cultures

Summary An increase in the production of macrophage migration inhibitory factor, chemotactic factor for neutrophils, and skin reactive factor, was observed in lymphocyte cultures if the cells were allowed to age in culture for 24 h. The increased lymphokine production was reduced by adding concanavalin A-stimulated and mitomycin C-treated suppressor cells. It is suggested that the lymphokine production could be regulated by suppressive mononuclear cells.This work was supported by the Scientific Research Council, Ministry of Health, Hungary (Code No. 421 0304011/S).     

Corticosteroid effects on cholinergic enzymes in ethanol-treated fetal brain cell cultures

In the presence of ethanol, corticosterone and dexamethasone inhibit choline acetyltransferase and acetyl-cholinesterase activities in cultured fetal brain cells of the rat. These results suggest that corticosteroids may have an important influence on the activity of cholinergic enzymes in the fetal brain may antagonize the effects of ethanol in this setting.