Relationship of the Escherichia coli TrkA system of potassium ion uptake with the F0F1-ATPase under growth conditions without anaerobic or aerobic respiration.

K+ uptake by the Escherichia coli TrkA system is unusual in that it requires both ATP and deltamuH+; a relation with H+ circulation through the membrane is therefore suggested. The relationship of this system with the F0F1-ATPase was studied in intact cells grown under different conditions. A significant increase of the N,N'-dicyclohexylcarbodiimide(DCCD)-inhibited H+ efflux through the F0F1 by 5 mM K+, but not by Na+ added into the potassium-free medium was revealed only in fermenting wild-type or parent cells, that were grown under anaerobic conditions without anaerobic or aerobic respiration and with the production of H2. Such an increase disappeared in the deltaunc or the trkA mutants that have altered F0F1 or defective TrkA, respectively. This finding indicates a closed relationship between TrkA and F0F1, with these transport systems being associated in a single mechanism that functions as an ATP-driven H(+)-K(+)-exchanging pump. A DCCD-inhibited H(+)-L(+)-exchange through these systems with the fixed stoichiometry of H+ and K+ fluxes (2H+/K+) and a higher K+ gradient between the cytoplasm and the external medium were also found in these bacteria. They were not observed in cells cultured under anaerobic conditions in the presence of nitrate or under aerobic conditions with respiration and without production of H2. The role of anaerobic or aerobic respiration as a determinant of the relationship of the TrkA with the F0F1 is postulated. Moreover, an increase of DCCD-inhibited H+ efflux by added K+, as well as the characteristics of DCCD-sensitive H(+)-K(+)-exchange found in a parent strain, were lost in the arcA mutant with a defective Arc system, suggesting a repression of enzymes in respiratory pathways. In addition, K+ influx in the latest mutant was not markedly changed by valinomycin or with temperature. The arcA gene product or the Arc system is proposed to be implicated in the regulation of the relationship between TrkA and F0F1.

[Role of Arc-system for the control of synthesis of respiratory enzymes in regulation of K+-transporting system in glycolysing Escherichia coli]. / Rol' Arc-sistemy kontrolia sinteza fermentov dykhatel'nogo metabolizma v reguliatsii raboty K+-transportnoi sistemy u glikoliziruiushchikh bakterii Escherichia coli.

It is shown that the uptake of K+ ions by anaerobically grown E. coli bacteria, which perform glycolysis with the production of H2 in exchange for H+ ions, which are extruded from the cells, occurs with a fixed stoichiometry of N,N'-dicyclohexylcarbodiimide-sensitive ion fluxes (2H+/K+). This process is observed in the precursor strain and arcB mutant, and is destroyed in arcA mutant. The K(+)-uptake by the latter mutant, which proceeds with a moderate affinity (KM 2.0 mM) and is triggered by a positive shock, is sensitive to external osmotonicity. The K(+)-uptake by the arcA mutant is also inhibited by N,N'-dicyclohexylcarbodiimide and has a variable stoichiometry of N,N'-dicyclohexylcarbodiimide-sensitive ion fluxes and does not significantly change in the presence of valinomycin and with varying temperature, whereas the intracellular activity of K+ ions is lower. The Arc-system for the control of synthesis of respiratory enzymes in E. coli participates in the regulation of the K(+)-transporting TrkA system, which directly interacts with F0F1 H-ATPasa; this system in the arcA mutant operates independent of F0F1 and interacts with the latter by mediation of the proton gradient.

[Effect of temperature on H+-K+ exchange in Escherichia coli bacteria during their anaerobic growth]. / Vliianie temperatury na H+-K+-obmen u bakterii Escherichia coli pri ikh anaérobnom vyrashchivanii.

The H(+)-K(+)-exchange in E.coli grown under anaerobic conditions at temperatures from 17 to 37 degrees C was studied. The Arrhenius plots for both the N,N'-dicyclohexylcarbodiimide-sensitive release of H+ and K+ uptake by cells transferred into a fresh medium containing a carbon source (glucose) are nonlinear. The activation energy values for the transport of these cations at different temperatures significantly differ. It is shown that as the temperature decreases, the accumulation of K+ by cells is reduced. In this process, the initial rate of K+ absorption through the TrkA system, the time of accumulation of these cations by cells and the osmosensitivity of K+ uptake substantially decrease. At temperatures below 20 degrees C, the absorption becomes insensitive to the secondary osmoshock. However, the stoichiometry of N,N'-dicyclohexylcar-bodiimide-sensitive cation fluxes remains unchanged and is equal to 2H+:K+. It is assumed that the H(+)-K(+)-exchange proceeds by the operation of an ensemble of oligomers, formed from the protomers of F0F1 and TrkA, which rearrange by the action of temperature, whereas F0F1 and TrkA in each protomer do not change.

[Surgical tactics in acute obturation obstruction of the large intestine of tumor etiology]. / Khirurgicheskaia taktika pri ostroi obturatsionnoi tolstokishechnoi neprokhodimosti opukholevoi étiologii.

The article deals with the results of treatment of 300 patients with acute obstruction of the colon of neoplastic etiology. Patients over 60 years of age accounted for 69.7% of cases. Among 300 patients 211 were subjected to emergency operation. The total mortality was 31.3%. Peritonitis was found during the operation in 81.7% of patients, perforation of the colon was revealed in 53 of them. Stage IV carcinoma was found in 74 patients. The authors point out that late operations lead to poorer outcomes of the disease and suggest performing the surgical intervention no later than 6 hours after hospitalization. The expediency of two-stage (mortality rate 17.0%) and three-stage (mortality rate 17.9%) operations is noted because their results are better than those of a radical one-stage operation (mortality rate 46.1%).

[Injury of the duodenum in closed abdominal trauma]. / Povrezhdenie dvenadtsatiperstnoi kishki pri zakrytoi travme zhivota.

Analysis of 11 cases with injury to the duodenum showed that the presence of a hematoma, gelatinous pulmonary edema, and yellowish-green fatty tissue around the duodenum are evidence of the possible damage of its retroperitoneal part. Closure of the duodenal defect with double-row silk sutures and their peritonization with a free area of the parietal peritoneum is advisable. In retroperitoneal rupture of the duodenum the operation must be completed by drainage of the retroperitoneal space and decompression of the beginning of the small intestine with a nasogastric catheter. The possible complications are described. The Postoperative mortality was 36.3%.