Role of vitamin B 12 in the incorporation of ribonucleosides into the DNA of various Periplaneta americana cell lines]

Hemocytes and non hemocytes in vitro cell lines from Periplaneta americana, have been tested for their ability to incorporate, in the presence of vitamin B 12, various nucleic acid precursors into their DNA. Evidence was shown for enhanced transformation of all ribonucleotides into deoxyribonucleotides in the presence of vitamin B 12. Moreover, in hemocyte cell lines, it was demonstrated that vitamin B 12 produced an activation of thymidine kinase activity.     

多项式微分系统的不变直线的不同斜率的最大个数

本文证明了公式β（ｎ）＝σ（ｎ－１）＋１其中α（ｎ－１）是ｎ－１次多项式微分系统的不为直线的最多条数，βｎ）是ｎ次多项式微分系统的不变直线的不同斜率的最大个数。这里假设所讨论的多项式系统只有限条不变直线。     

Insect hemocytes: Cells adapted to anaerobiosis

Summary Hemocytes from a free-living insect could be grown under strictly anoxic conditions. Their anaerobic metabolism was studied in vitro in such a cellular system.We thank Dr C. Remesy for analysing the volatile fatty acids and Drs P. Dejours and J. Girard for helpful discussions.     

Cyanocobalamine as a support of the in vitro cell growth-promoting activity of serum proteins

Résumé La mise au point d'un milieu synthétique pour cellules d'insectes a permis de caractériser deux actions complémentaires des protéines du sérum qu'il fallait jusqu'alors ajouter au milieu de culture. La première, revient à une protection des cellules par les antiprotéases du sérum, notamment à l'occasion de leur repiquage. L'autre, objet de ce travail, établit le rôle de certaines protéines-transport, et plus particulièrement de celles servant de support à la vitamine B₁₂.