Studies on the relationship between glycolysis and (Na++K+)-ATPase in cultured cells

In several tissues a coupling between glycolysis and (Na⁺+K⁺)-ATPase has been observed. We report here studies on the coupling of glycolysis and (Na⁺+K⁺)-ATPase in Rous-transformed hamster cells and Ehrlich ascites tumor cells. The rate of (Na⁺+K⁺)-ATPase was estimated by the initial rate of ouabain-sensitive K⁺ influx after K⁺ reintroduction to K⁺-depleted cells. Experiments were performed with cells producing ATP via oxidative phosphorylation alone (i.e., lactate sole substrate), glycolysis alone (i.e., glucose as substrate in the absence of oxygen or with antimycin A), or glycolysis and oxidative phosphorylation (i.e., glucose as substrate in the presence of oxygen). The cells produced ATP at approximately the same rate under all of these conditions, but the initial rate of K⁺-influx was approx. 2-fold higher when AtP was produced from glycolysis. Changes in cell Na⁺ due to other transport processes related to glycolysis, such as Na⁺-H⁺ exchange, Na⁺-glucose cotransport, and K⁺-H⁺ exchange were ruled out as mediators of this effect on (Na⁺+K⁺)-ATPase. These data suggest that glycolysis is more effective than oxidative phosphorylation in providing ATP to (Na⁺+K⁺)-ATPase to these cultured cells.     

The neurochemical basis of recurrent inhibition in the reflex arch of the defensive reaction]

Mechanisms of habituation in the network of identified neurones were investigated in isolated preparation of central nervous system in the snail Helix. It has been found that intracellularly induced spike discharge in premotor command neurones decreases synaptic responses to repeated nerve stimulation in all recorded command neurones. Application of the neuropeptide FMRFamide elicits similar changes in the network. Taking into account that the investigated command neurones contain FMRFamide, as was shown immunochemically, it is possible to assume the existence of recurrent inhibition in the network underlying avoidance reactions. This recurrent inhibition causes habituation of the network output in the cases when the repeated stimuli do not evoke sensitization via activation of serotonergic cells.     

High-resolution imaging reveals a limit in spatial resolution of blood flow measurements by microspheres

Density of 15-microm microspheres after left atrial application is the standard measure of regional perfusion. In the heart, substantial differences in microsphere density are seen at spatial resolutions <5 ml, implying perfusion heterogeneity. Microsphere deposition imaging permits a superior evaluation of the distribution pattern. Therefore, fluorescent microspheres (FMS) were applied, FMS deposition in the canine heart was imaged by epifluorescence microscopy in vitro, and the patterns were observed compared with MR images of iron oxide microspheres (IMS) obtained in vivo and in vitro. FMS deposition in myocardial slices revealed the following: 1) a nonrandom distribution, with sequentially applied FMS of different color stacked within the same vessel, 2) general FMS clustering, and 3) rather large areas devoid of FMS (n = 3). This pattern was also seen in reconstructed three-dimensional images (<1 nl resolution) of FMS distribution (n = 4). Surprisingly, the deposition pattern of sequentially applied FMS remained virtually identical over 3 days. Augmenting flow by intracoronary adenosine (>2 microM) enhanced local microsphere density, but did not alter the deposition pattern (n = 3). The nonrandom, temporally stable pattern was quantitatively confirmed by a three-dimensional intermicrosphere distance analysis of sequentially applied FMS. T2-weighted short-axis MR images (2-microl resolution) of IMS revealed similar patterns in vivo and in vitro (n = 6), as seen with FMS. The observed temporally stable microsphere patterns are not consistent with the notion that microsphere deposition is solely governed by blood flow. We propose that at high spatial resolution (<2 microl) structural aspects of the vascular network dominate microsphere distribution, resulting in the organized patterns observed.     

Biosynthesis of the subtilisin-like serine proteinase of Bacillus intermedius under salt stress conditions

The biosynthesis of the subtilisin-like serine proteinase of Bacillus intermedius 3-19 by the recombinant strain Bacillus subtilis AJ73(pCS9) was found to be enhanced under salt stress conditions (growth in a medium containing 1 M NaCl and 0.25 M sodium citrate). In a recombinant strain of B. subtilis deficient in the regulatory proteins DegS and DegU, which control the synthesis of degradative enzymes, the expression of the proteinase gene was inhibited. In contrast, in the strain B. subtilis degU32 (Hy), which provides for the over-synthesis of proteins positively regulated by the DegS-DegU system, the biosynthesis of the subtilisin-like proteinase of B. intermedius 3-19 increased by 6-10 times. These data suggest that the DegS-DegU system is involved in the positive regulation of the expression of the subtilisin-like B. intermedius proteinase gene in recombinant B. subtilis strains.     

Calcium activation of heart mitochondrial oxidative phosphorylation: rapid kinetics of mVO2, NADH, AND light scattering

Parallel activation of heart mitochondria NADH and ATP production by Ca(2+) has been shown to involve the Ca(2+)-sensitive dehydrogenases and the F(0)F(1)-ATPase. In the current study we hypothesize that the response time of Ca(2+)-activated ATP production is rapid enough to support step changes in myocardial workload ( approximately 100 ms). To test this hypothesis, the rapid kinetics of Ca(2+) activation of mV(O(2)), [NADH], and light scattering were evaluated in isolated porcine heart mitochondria at 37 degrees C using a variety of optical techniques. The addition of Ca(2+) was associated with an initial response time (IRT) of mV(O(2)) that was dose-dependent with a minimum IRT of 0.27 +/- 0.02 s (n = 41) at 535 nm Ca(2+). The IRTs for NADH fluorescence and light scattering in response to Ca(2+) additions were similar to mV(O(2)). The Ca(2+) IRT for mV(O(2)) was significantly shorter than 1.6 mm ADP (2.36 +/- 0.47 s; p < or = 0.001, n = 13), 2.2 mm P(i) (2.32 +/- 0.29, p < or = 0.001, n = 13), or 10 mm creatine (15.6.+/-1.18 s, p < or = 0.001, n = 18) under similar experimental conditions. Calcium effects were inhibited with 8 microm ruthenium red (2.4 +/- 0.31 s; p < or = 0.001, n = 16) and reversed with EGTA (1.6 +/- 0.44; p < or = 0.01, n = 6). Estimates of Ca(2+) uptake into mitochondria using optical Ca(2+) indicators trapped in the matrix revealed a sufficiently rapid uptake to cause the metabolic effects observed. These data are consistent with the notion that extramitochondrial Ca(2+) can modify ATP production, via an increase in matrix Ca(2+) content, rapidly enough to support cardiac work transitions in vivo.     

Reverberation of excitation in "hippocampus-entorhinal cortex" slices in rats. Optical recording

Using RH155 voltage-sensitive dye and photodiode array for optical recording, responses to electrical stimuli were investigated in rat brain slices, which included hippocampus and entorhinal cortex. It was shown that single electrical stimulation of the entorhinal cortex, subiculum, or dentate gyrus evoked a potential consecutively spreading from the dentate gyrus to the CA3 and then CA1 hippocampal areas. When the GABAergic inhibition was partially blocked by picrotoxin, the first excitation wave was followed by additional several waves. Such secondary waves were observed in all the hippocampal areas with a constant trial-to-trial latency shift increasing in the direction from the dentate gyrus to CA3 and CA1 areas. Reverberation of activity between the hippocampus and entorhinal cortex is regarded as the most probable cause of appearance of the secondary excitation waves.     

Protein synthesis-dependent reactivation of environmental conditioned reflex in terrestrial snails

We investigated influence of anisomycine injection on reconsolidation of contextual memory after development of environmental conditioned reflex in terrestrial snail Helix. Testing the amplitude of behavioral reactions (tentacle withdrawal) in response to standard tactile stimulation of the skin in two contexts: a) when the snail was fixed by the shell and was moving on the surface of the ball floating in water, or b) was moving on the flat surface of glass terrarium, has shown no difference in response amplitudes. After a session of electric shocks (5 days) in one context only (ball) the associative learning was clearly observed as the significant difference of response amplitudes in two contexts. On the other day following testing was performed a session of "reminding", immediately after which the snails were injected by anisomycine (control snails were injected by saline solution). Testing has shown that injection of anisomycine led to impairment of the context conditioning. Results suggest that the mechanisms of consolidation of new memory and memory reconsolidation after retrieval are not identical.     

Organization of the workers of the State Sanitary and Epidemiologic Services of the Stavropol Territory in the period of eradication of the consequences of the flood in urban and rural regions of the Territory in 2002

As the result of high flood occurring during the period of June 21-22, 2002, in the Stavropol Territory, 65 settlements were affected. About 200,000 inhabitants found themselves lacking centralized drinking water supply. From the very first days of the emergency situation the state sanitary and epidemiological service took a complex of measures aimed at the liquidation of the medico-sanitary consequences of the high flood, the prevention of the appearance of mass infectious diseases among the affected population. As the result of these measures, the appearance of the outbreaks of acute enteric infections, viral hepatitis A aggravations in malaria and other infectious diseases could be prevented.     

Realization of antimalarial measures in the period of eradication of the consequences of a flood in the Stavropol Territory in 2002

As the result of the high flood, an increase in the area of anopheligenic water reservoirs occurred on the inundated territories, which created favorable conditions for the proliferation of Anopheles mosquitoes, the vectors of malarial plasmodia, thus creating the threat of the formation of the local sources of malaria in case of its penetration from other regions unfavorable with respect to this disease. In the affected towns and regions hydrotechnical measures aimed at decreasing the surface of anopheligenic water reservoirs, as well as measures aimed at the decrease in the number of the larval and imaginal stages in the development of mosquitoes, were taken, which made it possible to prevent the probable epidemiological aggravations in malaria.     

Phase-dependent coordination of two motor programs in the buccal ganglion of a pteropod mollusk

Rhythmic activities of two feeding structures of the pteropod mollusk Clione limacina, redula and hooks, controlled by the neural networks in the buccal ganglia must be coordinated in order to produce a meaningful feeding response. Optical recording from the buccal ganglia, which allows the simultaneous activities of numerous neurons to be traced, revealed that such coordination exists in a phase-dependent manner. Instead of recording four theoretically possible phases of neuronal rhythmic activity, we always recorded only two phases, even after the electrical stimulation of the cerebro-buccal connective, which triggers both radula and hook rhythmic movements in the preparation.