Thermodynamics of growth. Non-equilibrium thermodynamics of bacterial growth. The phenomenological and the mosaic approach

Microbial growth is analyzed in terms of mosaic and phenomenological non-equilibrium thermodynamics. It turns out that already existing parameters devised to measure bacterial growth, such as YATP, mu, and Q substrate, have as thermodynamic equivalents flow ratio, output flow and input flow. With this characterisation it becomes possible to apply much of the already existing knowledge of phenomenological non-equilibrium thermodynamics to bacterial growth. One of the conclusions is that the frequent observation that YATP is only 50% of its theoretical maximum does not mean that the microbe corresponds to a thermodynamic system that has been optimized for maximal output power, as has been suggested. Rather, at least in some cases, it corresponds to a system that has been optimized towards maximum growth rate. When the degree of reduction of the (single) carbon source is significantly smaller than that of the biomass produced, the efficiency of biomass synthesis has been kept as high (i.e., about 24%) as is consistent with maximization of the growth rate at optimal efficiency. Mosaic thermodynamics allows an analysis of processes which in microbial metabolism may be responsible for any particular growth behaviour. Equations are derived that predict the effect of uncoupling through leaks, futile cycling, or 'slip' on microbial growth. It turns out that uncoupling is expected to affect both the growth rate-independent and the growth rate-dependent 'maintenance coefficient'. The effect on the latter is different when catabolic substrate limits growth than when anabolic substrate limits growth. In the latter case, the growth rate-dependent maintenance coefficient is negative. It is concluded that mosaic non-equilibrium thermodynamics will be a powerful theoretical tool especially in future experimental analyses of the metabolic basis for microbial growth characteristics and growth regulation.

[Use of ultrasound, ultrasound-directed fine needle puncture and aspiration in amebic abscess of the liver. Case report and short overview]

Case report on a 48-year-old Swiss male living in Burundi who suddenly fell ill with vomiting and anorexia, followed by pappy stools, weakness and impotence. He presented with hepatomegaly, while sedimentation rate and alkaline phosphatase were both elevated. Stool examination revealed cysts and vegetative forms of Entamoeba histolytica, while amebic serology was negative. Treatment with ornidazole and later with diloxanide furoate was given. Sonography showed two cystoid areas in the right lobe of the liver. In the third sonographically guided fine-needle puncture both lesions were fully aspirated. Amebic serological tests were now positive for the first time. Six weeks later the sonogram showed a normal liver feature. The symptomatology and diagnosis of hepatic amebic abscess are discussed, with special reference to the important role of sonographically guided fine-needle puncture and drainage. Sonographic technique and differential diagnosis are briefly demonstrated.

[Sonography vs. computer tomography in liver manifestations of echinococcosis]

Hepatic echinococcosis generally gives rise to typical signs by ultrasound and computed tomography, even though a relatively large number of conditions has to be considered in the differential diagnosis. Comparing the two methods in 29 patients with manifestations of hepatic involvement by echinococcosis it was demonstrated that ultrasound is only slightly inferior, in cases of small-size involvement, which fails to be diagnosed as focal disease of the liver parenchyma. But ultrasound is the primary method of investigation, especially when the differential diagnosis is still open, and it is preferred for serial studies during and after treatment. Computed tomography is the method of choice particularly when it is necessary pre-operatively to document involvement beyond the liver itself.

[Ultrasound-controlled fine needle puncture of gastrointestinal tumors with continuous view]

On account of its principle, ultrasound tomography cannot be recommended as a screening method for intestinal tumors; nevertheless, it may sometimes demonstrate larger tumors not producing typical signs. These neoplasms show a characteristic pattern ("cockade phenomenon"). In the region of the antrum they appear occasionally as a rigid thickening of the gastric wall. The nature of such an expansive lesion may be evaluated quickly and safely by a fine-needle puncture performed under sonographic control. No complications have been observed so far.

Lactate efflux-induced electrical potential in membrane vesicles of Streptococcus cremoris

We developed a procedure for isolating membrane vesicles from the homolactic fermentative bacterium Streptococcus cremoris. The membrane vesicles were shown to have a right-side-out orientation by freeze-etch electron microscopy and to be free of cytoplasmic constituents. The membrane vesicles retained their functional properties and accumulated the amino acids L-leucine, L-histidine, and L-alanine in response to a valinomycin-induced potassium diffusion gradient. Studies with these membrane vesicles strongly supported the possibility that there was a proton motive force-generating mechanism by end product efflux (Michels et al., FEMS Lett. 5:357-364, 1979). Lactate efflux from membrane vesicles which were loaded with L-lactate and diluted in a lactate-free medium led to the generation of an electrical potential across the membrane. The results indicate that lactate efflux is an electrogenic process by which L-lactate is translocated with more than one proton.

[Percutaneous cholecysto- and cholangiography (author's transl)]

Combined sonographic and radiographic investigations of the biliary duct system using direct percutaneous transhepatic fine needle puncture under constant visualisation and contrast medium demonstration were done in 37 patients. The results show numerous advantages of the method: 1. It is very safe as all tissue and organ areas are under constant surveillance. 2. There is almost no risk of infection. 3. The investigation can be performed on predamaged liver parenchyma. 4. Cytologic material can be obtained; there are no extravasates. The information value of this combined investigation method is greater in a similar group of indications than with radiographic or sonographic methods alone. It appears possible that the risks of ERCP and PTC may be reduced. Further investigations will have to establish the clinical value and risks of this new method.

[Vocational rehabilitation of heart patients. An analysis of "vocational rehabilitation cases" closed by the federal employment institute (author's transl)]

The number of heart/circulatory disease rehabilitation cases closed annually by the Federal Employment Institute has remained almost the same over the 1972-1978 period. In 1978 the national total of closed heart/circulatory disease cases amounted to 6,325, with 945 of the clients having attended vocational rehabilitation measures/courses. Some 25 percent of the cases are classified as "condition following myocardial infarction"; in male clients, this applies to about one third. Compared to the number of male clients, women are strongly under-represented in vocational rehabilitation of heart/circulatory disease patients. In relation to the structure of the gainfully employed population total, the frequency of vocational rehabilitation measures on heart/circulatory disease diagnoses varies strongly among the individual Laender employment office districts. Considerable differences are apparent when the age structure of heart/circulatory disease rehabilitation cases is compared with that of any other disability group. In case of the first, the number of cases increases with age, while the trend is the very opposite in the latter case. This fact shows that vocational rehabilitation measures for heart/circulatory disease patients need come up to special conditions, and that they have to be determined on different criteria. The rate of integrational solutions considered a positive outcome is considerably lower for heart/coronary disease rehabilitees than for the total of rehabilitees. The participation in vocational rehabilitation programmes of 14.9 percent equally is considerably lower than the corresponding percentage of the total number of rehabilitation cases (26.2 percent).

[Ultrasonic findings in renal diseases with hypertension (author's transl)]

Ultrasound investigations of the kidney were performed in a prospective study in 51 patients with hypertension. It was shown by means of characteristic changes that renovascular and renal parenchymatous diseases can be differentiated. The case of renal atrophy could be demonstrated in 14 out of 20 cases with renovascular changes and in 15 out of 18 cases wtih primary renal parenchymatous disease. There were false positive results in two out of 13 cases of essential hypertension. The importance of intrarenal cysts in the aetiology of hypertension requires further investigation.

[Sonography in the evaluation of reduced function of kidney transplants (author's transl)]

Sonography of 58 kidney transplants has been performed in 56 patients and morphological alterations have been registrated. These results have been compared with clinical examination, blood samples and histological evaluation whenever possible. It is our opinion that certain sonographical phenomena exist, which make the rejection of kidney transplants most probable and even allow for differentiation of different degrees. We found a correlation of right results between sonography and final pathological diagnosis in more than 80% of our patients. Moreover sonography permits the diagnosis of ureteral obstruction or leakage.

[Antidesoxyribonuclease B-titer in persons of different ages and sex and comparative studies of antistreptolysin titers]

The antidesoxyribonuclease B reaction shows in persons of all classes of age examined a similar distribution of titres as the antistreptolysin reaction. The anti DNase B titres however are mostly lower than the titres of the antistreptolysin reaction, except in the group of children, 6 to 17 years of age, suffering frequently from latent infections of streptococci. Women in childbed showed lower anti DNase B titres than other persons of corresponding age. Among persons with anti DNase B titres higher than antistreptolysin titres predominate men.

[Experience with sonographically controlled fine-needle punctures with permanent visual control (author's transl)]

With our new biopsy-device it is now possible to perform fine-needle punctures of lesions in the abdomen, thoracic cage, cervical region and extremities under continuous visual control. This intervention can easily be done with low risk for the patient and can be repeated whenever necessary. It has proven its advantages for amniocentesis as well, especially in cases with a low amount of amniotic fluid. Moreover, our new device allows the combination of sonographical and radiological interventions, for example of the kidneys.

Generation of an electrochemical proton gradient in Streptococcus cremoris by lactate efflux

Recently an energy-recycling model was proposed that postulates the generation of an electrochemical gradient in fermentative bacteria by carrier-mediated excretion of metabolic end products in symport with protons. In this paper experimental support for this model is given. In batch cultures of Streptococcus cremoris with glucose as the sole energy source the maximal specific growth rate decreased by 30% when the external lactate concentration was decreased from 50 to 90 mM. In the same range of external lactate concentrations the molar growth yield Y for glucose as measured in energy-limited chemostat cultures also showed a 30% drop. From Y max lactose values of S. cremoris grown in the presence and absence of added lactate it was calculated that the net energy gain from the lactate efflux system was at least 12%. Lactate efflux from de-energized cells loaded with lactate could drive the uptake of leucine. This uptake was sensitive to carbonylcyanide p-trifluoromethoxyphenylhydrazone and was only partly inhibited by dicyclohexylcarbodiimide (DCCD). The limited inhibition by DCCD of lactate-induced leucine uptake indicates that ATP hydrolysis was not the driving force for transport of leucine. Uptake studies with the lipophilic cation tetraphenylphosphonium demonstrated that lactate efflux increased the electrical potential across the membrane by 51 mV. The generation of an electrical potential by lactate efflux and the demonstration of a potassium efflux-induced uptake of lactate indicates that lactate is translocated across the membrane by a symport system with more than one proton.

[Ultrasonically guided percutaneous fine needle aspiration biopsy of pancreatic tumours under permanent visual control (author's transl)]

Using a new method of ultrasonically guided fine needle biopsy under permanent visual control it is now possible to biopsy tumour-suspect changes of the pancreas and other abdominal organs reliably. The risk for the patient can thus be reduced to a minimum. The method leads to considerable improvement in obtaining biopsy material and is easily performed and may be repeated. The correct diagnosis could be established in all of 18 patients with pancreatic disease by cytological investigation. Sonographic interpretation of space occupying pancreatic lesions was successful in only 16 patients.