Fluorescence of eosinophil leucocyte granules induced by 1-hydroxy-3,6,8-pyrenetrisulfonate. Visualization of differences in protein isoelectric points

After treatment of horse, rat and human blood smears with alkaline solutions of 1-hydroxy-3,6,8-pyrenetrisulfonate (HPTS), eosinophil leucocyte granules were the unique cell components which showed a bright green fluorescence. When stained with HPTS at pH 10, the whole granule of horse eosinophils showed high emission which strongly diminished after washing or staining in salt solutions or by using blocking methods for amino groups. Using HPTS at pH 12, the fluorescence reaction of house granules was specifically located in the peripheral region, appearing as fluorescent rings. These microscopic observations, which indicate differences in the isoelectric point of proteins within the eosinophil granule, were also confirmed by HPTS staining of protein blots as model substrates. Spectral analysis of HPTS at pH 10 and 12 showed practically identical absorption and emission spectra with peaks at 450 nm and 510 nm, respectively. Our results indicate that mainly ionic binding occurs between cationic proteins and HPTS in alkaline solution, and that the most cationic proteins (with isoelectric points at pH higher than 12) are located in the peripheral annular region of horse eosinophil granules.     

Viscosity decrease of pectin and fruit juices catalyzed by pectin lyase from Penicillium italicum in batch and continuous-flow membrane reactors

Summary The extracellular pectin lyase (PNL, E.C. 4.2.2.10) from Penicillium italicum was utilized in batch and confined in a continuous-flow ultrafiltration membrane reactor. The enzyme catalyzed the decrease in viscosity of pectin solutions at pH 6.0 as well as of different fruit juices at their respective pH. PNL decreased the viscosity of pectin solutions in the membrane (60% after 30 min) more than in the batch (46% after 70 min) reactors, but similar viscosity reduction of fruit juices was achieved in both reactors. The enzyme decreased the viscosity of grape, peach and melon juices to different extents, but failed to do so with apple or pear juices. It can be concluded that the utilization of PNL in a membrane reactor appears of interest for the clarification of fruit juices.     

Automatic gas meter for laboratory fermenters

Summary A versatile, cheap and automated system is designed for the measurement of small gas flows produced in laboratory-scale fermentation processes. An automatic sampling device for programmed times is linked to the flow meter. The displacement of a liquid by the gas being measured is the principle on which both the meter and the sampling device are based. The operation of the system is controlled by a simple electronic circuit.     

Effect of growth supplements and whey pretreatment on butyric acid production by Clostridium butyricum

Improved production of butyrate (up to 19 g/l) from whey by Clostridium butyricum was achieved by adding either yeast extract (5 g/l) or biotin (50 g/l). Hydrolysed lactose and proteolysed whey were less effective even with added biotin.The authors are with the Department of Biochemical Technology, Faculty of Chemical Technology, Slovak Technical University, Radlinského 9, Bratislava 812 37, Slovakia     

Synthesis of new azino fused benzimidazolium salts. a new family of DNA intercalating agents. I

A series of new pyrido[1,2-a]- and pyridazino[1,6-a]benzimidazolium salts have been synthesized from readily available 1,3-disubstituted 2-alkylbenzimidazolium salts. Their affinity to DNA and in vitro cytotoxicity versus HT-29 have been tested. The initial results show that the title compounds are a new family of intercalating agents.     

Postjunctional Origin of the indirect-like sympathomimetic effect of metanephrine and normetanephrine on blood pressure

The effects of metanephrine and normetanephrine have been compared with those from equiactive doses of the origin compounds, adrenaline and noradrenaline, on the pressor responses in rat, in order to determine whether their effects are owed, at least partially, to a releasing presynaptic action of the catecholamines in normal animals as well as those pretreated with reserpine, guanethidine and 6-OH-dopamine. Their effects have likewise been studied in isolated perfused renal arteries both in normal and reserpinized rats. None of the adrenolytic agent used were able either to reduce the duration of the hypertensive response or to accelerate tachyphylaxis. Identical results were obtained in renal artery preparations. It is thus concluded that the catecholamines stored in presynaptic endings are not involved in the observed phenomena and it is suggested that they might depend on the high doses required to produce effects equiactive to those of the origin substances.     

Immobilization of the cellulolytic fungus Trichoderma reesei on the polymeric sorbent - Sorfix

Summary The immobilization of T. reesei mycelium on activated polymeric sorbent was investigated with respect to the intended flow-trough cellulase production. The retention of extracellular production of cellulolytic enzymes was monitored in a packed-column recycle reactor. Some factors affecting cellulase elution pattern are described.     

A kinetic study of the interaction of vanadate with the Ca2+ + Mg2+-dependent ATPase from sarcoplasmic reticulum.

Ca2+ + Mg2+-dependent ATPase from sarcoplasmic reticulum was inhibited by preincubation with vanadate. When the inhibited enzyme was preincubated in the presence of vanadate and assayed in its absence, a slow reactivation process was observed. This slow, hysteretic, process was exploited to study the influence of Ca2+ and ATP on the dissociation of vanadate. Ca2+ alone slowly displaced vanadate from the inhibited enzyme, and a rate constant of 0.1 min-1, at 25 degrees C, was calculated for this re-activation process. However, ATP re-activated with an apparent constant that hyperbolically depended on ATP concentration, and from it a rate constant for vanadate dissociation induced by ATP of 0.5 min-1 was calculated. It is deduced from the kinetic studies that ATP binds to the enzyme-vanadate complex, forming a ternary complex, with a dissociation constant of 4 microM, and that this binding accelerates vanadate dissociation. Binding experiments with [14C]ATP showed that ATP binds to the enzyme-vanadate complex with a dissociation constant of 12 microM, i.e. the affinities calculated with the isotope technique and the kinetic procedure are of the same order of magnitude.