[The role of Ca2+ ions in a phage infection of Corynebacterium glutamicum]. / Rol' ionov Ca2+ v fagovoi infektsii Corynebacterium glutamicum.

It was shown that neither uncouplers of oxidative phosphorylation, nor lack of Ca2+ ions affected the normal MC-2 phage absorption on Corynebacterium glutamicum cells, while the phage development was repressed under these conditions. Simultaneous measurement of Ca2+, K+ and H+ ion flows, as well as measurement of membrane potential showed that the addition of the phage into the experimental medium led to significant depolarization of the membrane from -160 mV to -100 mV due to the penetration of Ca2+ ions into the cells followed by K+ and H+ efflux. The (Ca2+) to (K+ + H+) ratio was shown to be 1 : 1. Phage DNA is supposed to be injected into the host cells as a positively charged (Ca2+-DNA) complex.

[The capacity of anaerobically grown bacteria to exchange the 2H+ of the cell for the K+ of the medium and to maintain a high K+ distribution between cell and medium]. / Issledovanie sposobnosti anaérobno vyrashchennykh bakterii obmenivat' 2H+ kletki na K+ sredy i podderzhivat' vysokoe raspredelenie K+ mezhdu kletkoi i sredoi.

The N,N'-dicyclohexylcarbodiimide sensitive exchange of 2H+ of a cell for K+ of medium stable to pH, K+ activity and temperature changes has been discovered in anaerobically grown gram-negative Escherichia coli, Salmonella typhimurium. S. enteritidis, Proteus mirabilis, P. vulgaris, anaerobic gram-positive bacteria Streptococcus faecalis, Lactobacillus salivarius, L. lactis in the presence of exogenic energy source. This exchange in gram-negative bacteria is operating only at increase of medium osmolarity. The high K+ distribution between cell and medium has been reached during the exchange of 2H+ for one K+ and the corresponding potassium equilibrium potential is much more than the measured delta psi. In aerobically grown E. coli, S. typhimurium, Brevibacterium flavum and aerobic Micrococcus luteus exchange of 2H+ for K+ does not take place, the K+ distribution is lower and in good conformity with the measured delta psi. It is assumed that exchange of 2H+ for K+ in anaerobic bacteria is carried out by the H+-ATPase complex and the Trk (or Trk-like) system of K+ absorption united into the same membrane supercomplex which functions as the H+-K+-pump and supports the high K+ distribution between cell and medium.

[Biphasic energy-dependent potassium ion absorption by Escherichia coli cells]. / Dvukhfaznoe énergozavisimoe pogloshchenie ionov kaliia kletkami Escherichia coli.

The E. coli cells remove acid and accumulate potassium ions in two phases in the presence of glucose. The first phase (5-7 min) takes place only with an increase of external osmolarity; the second phase begins after 20 min and is not sensitive to alteration of the osmotic pressure. Potassium efflux occurs between two phases of K+-accumulation in alkaline media. Replacement of glucose by lactate results in a decrease of the first phase and abolition of the second one. The initial rate of K+-uptake for the first phase is a saturation curve in the range of 6 mM of external potassium concentration. These data indicate that the osmosensitive system of K+-uptake is connected with the first phase.

[Proton-potassium exchange in Escherichia coli]. / Protonno-kalievyi obmen u Escherichia coli.

Energy-dependent proton--potassium exchange in E. coli is suppressed by both ionophores and the inhibitor of hydrogen pumps N,N'-dichlohexilcarbodimide (DCCD). The ratio of DCCD-sensitive fluxes of H+ and K+ is equal to 2:1 and does not depend upon the values of ionic fluxes, external pH, osmolarity and temperature. Bacteria can absorb synthetic cation tetraphenilphosphonium (TPP+) both in the absence of glucose and at addition of this source of energy. In the presence of glucose TPP+-ions are taken up by cells during the first 5-10 min and then they leave cells. Such glucose--dependent kinetics of TPP+ accumulation coincides with that for the first rapid phase of K+ uptake, but the process is observed, only if the glucose--independent absorption of TPP+ is small. The amount of accumulated TPP+ may be ascribed to the membrane potential of E . coli equalling--180mV. It is therefore considered that electrogenic proton-potassium pump sensitive to external osmolarity operates in E. coli cell membrane and exchanges 2H+ of the cell for 1K+ of external medium.