Heterocyst size variation in Nostoc muscorum has been surveyed in the presence and absence of tyrosine. The heterocyst size exhibited two major peaks under both conditions but one of the peaks shifted towards larger size in tyrosine-containing medium. Heterocysts of larger volume exhibited division in the latter medium which was not observed in medium lacking tyrosine. It is suggested that signals for cell division did not decay following differentiation of heterocyst in the presence of tyrosine.

• Publikační typ
• časopisecké články MeSH

The initial replication region of the chromosome on the replication map of M. phlei constructed by means of sequential mutagenesis in synchronous populations was accurately determined. By following the time shift of the replication moment of the genes bac and met in the control culture and in the culture with the initial inhibition of DNA synthesis by nalidixic acid the start of replication of the chromosome was determined at 15 min before replication of the gene ile. On the basis of the results obtained a scheme of the cell cycle in M. phlei was proposed. Intervals C and D depend on the generation time, become prolonged independently of each other and assume the whole cycle. The ratio C/(C + D) equals to 0.56 and the interval D has a value of 0.76 of the interval C. The mutual ratio of the intervals C : D is 1.3 : 1.0. The obtained results make it possible to form the assumption about mutual ratios between the chromosome replication and cell division in bacteria exhibiting slow growth rates.

• MeSH
• bakteriální chromozomy MeSH
• buněčný cyklus MeSH
• časové faktory MeSH
• DNA bakterií biosyntéza   MeSH
• Escherichia coli cytologie   MeSH
• kyselina nalidixová farmakologie   MeSH
• Mycobacterium phlei cytologie   genetika   MeSH
• Mycobacterium cytologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA bakterií MeSH
• kyselina nalidixová MeSH

Nalidixic acid was used for describing more accurately the terminal replication region of the Mycobacterium phlei chromosome. Cell division in synchronized cultures was not sensitive to this acid any more between 185-190 min, i.e. about 10 min after replication of the ser gene, the last of 24 genes of the replication map described so far. The replication of the chromosome was controlled by determining the position of the bac gene. Microscopic studies in phase contrast of the cells that were subjected for long time periods to nalidixic acid treatment at a bactericidal concentration showed elongated cells. The electronmicroscopic observation showed that a portion of the population influenced by nalidixic acid lyses, whereas other cells remain intact and resemble control cells.

• MeSH
• bakteriální chromozomy účinky léků   metabolismus   MeSH
• buněčné dělení účinky léků   MeSH
• DNA bakterií biosyntéza   MeSH
• kyselina nalidixová farmakologie   MeSH
• mapování chromozomů * MeSH
• Mycobacterium phlei účinky léků   genetika   růst a vývoj   MeSH
• Mycobacterium genetika   MeSH
• replikace DNA účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA bakterií MeSH
• kyselina nalidixová MeSH

Extensive cell division after synchronization of Escherichia coli 15 TAU by arginine and uracil starvation occurs only when DNA synthesis is permitted to proceed by at least a short pulse of thymine applied between 30 and 60 min after transfer of synchronized culture to thymine-free medium with arginine and uracil. The time schedule of synchronized cell division in dependence on the schedule of intervals of DNA synthesis and inhibition of DNA synthesis was determined. The termination of replication cycles which were not completed to the very end during arginine and uracil starvation seems to be the decisive event for subsequent cell division after synchronization.

• MeSH
• arginin metabolismus   MeSH
• buněčné dělení MeSH
• časové faktory MeSH
• DNA bakterií biosyntéza   MeSH
• Escherichia coli růst a vývoj   metabolismus   MeSH
• kolorimetrie MeSH
• kyselina nalidixová farmakologie   MeSH
• kyselina oxolinová farmakologie   MeSH
• mutace * MeSH
• počet buněk MeSH
• replikace DNA MeSH
• thymin metabolismus   MeSH
• uracil metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• arginin MeSH
• DNA bakterií MeSH
• kyselina nalidixová MeSH
• kyselina oxolinová MeSH
• thymin MeSH
• uracil MeSH

• MeSH
• aminokyseliny metabolismus   MeSH
• arginin metabolismus   MeSH
• buněčné dělení MeSH
• DNA bakterií biosyntéza   MeSH
• Escherichia coli cytologie   růst a vývoj   metabolismus   MeSH
• glukosa metabolismus   MeSH
• glycerol metabolismus   MeSH
• kultivační média MeSH
• mutace MeSH
• počet buněk MeSH
• thymin metabolismus   MeSH
• uracil metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aminokyseliny MeSH
• arginin MeSH
• DNA bakterií MeSH
• glukosa MeSH
• glycerol MeSH
• kultivační média MeSH
• thymin MeSH
• uracil MeSH

• MeSH
• buněčné dělení účinky léků   MeSH
• chemické jevy MeSH
• chemie MeSH
• chinoliny farmakologie   MeSH
• DNA bakterií biosyntéza   MeSH
• Escherichia coli cytologie   účinky léků   růst a vývoj   metabolismus   MeSH
• kyselina nalidixová farmakologie   MeSH
• kyselina oxolinová farmakologie   MeSH
• kyseliny karboxylové farmakologie   MeSH
• počet buněk MeSH
• replikace DNA účinky léků   MeSH
• thymin metabolismus   MeSH
• tritium MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• chinoliny MeSH
• DNA bakterií MeSH
• kyselina nalidixová MeSH
• kyselina oxolinová MeSH
• kyseliny karboxylové MeSH
• thymin MeSH
• tritium MeSH