[Effect of chronic exposure to low doses of ionized radiation on embryonal development of the Japanese quail].

Experiments on Japanese quail embryogenesis on a background of chronic exposure to gamma- and neutron doses comparable with the doses of ionized radiation inside the orbital space stations Mir and ISS, and exploration vehicles gave evidence that permanent absorption of low gamma-doses (0,15 cgy/d) did not impact development of the Japanese quail embryos. On the contrary, the neutron dose of 200 microgy/d imparted by the neutron flux of 30 particles/cm2s was hazardous to embryos as it caused morphological disorders in 12% of embryos.

A multi-center blinded prospective study of urine neural thread protein measurements in patients with suspected Alzheimer's disease.

Objective: To investigate the utility of a clinical laboratory ELISA format assay that measures neural thread protein (NTP) in urine in the assessment of patients presenting with cognitive symptoms.

Design: A prospective blinded multicentered study.

Setting: Eight US specialty clinics for the evaluation of cognitive or memory disorder or dementia, including memory disorder and dementia clinics, neurology clinics, and psychiatry clinics, in 8 states.

[Peculiarities of eye morphogenesis in embryonic Japanese quails developed in microgravity].

This work is a part of comprehensive research into the effects of space flight on Japanese quail ontogenesis. Analysis of eye morphogenesis in the embryonic Japanese quails developed in microgravity discovered considerable deviations and abnormalities. Ocular abnormalities in the embryonic quail were mainly micro-ophthalmic and associated with disproportional growth of the pigmental epithelium and neural retina which resulted in plication and a broken sandwich structure of the retina.

[Computer modeling in the study of mechanism of catalytic activity and the structure of active site of glutamine(asparagine)ase. I. Pharmacophore models of glutamine(asparagine)ase substrates].

Glutamine(asparagine)ase catalyses desamidation of both L-glutamine and L-asparagine, and their D-isomers. In this study the two-pharmacophore models of main enzyme substrates and their hydrolysed analogues were design. The received models reflect two stage of substrate interaction with the enzyme active site.

[Influence of hypodynamia on organism of Japanese quail].

The present study is a part of a more comprehensive investigation of the spaceflight effects on ontogenesis of the Japanese quail. Reported are data about the effects of a 33-day immobilization on behavior, physiology and the reproductive function of these birds. As was revealed in the experiment, immobilization reduces the mass of the quail body and leads to a number of reversible disorders in the reproductive function including a sharp decrease in oviposition in females and disturbances in spermatogenesis in males.

[Molecular and catalytic properties of bacterial glutamin-(asparagin-)ase].

The review summarizes and analyzes experimental evidence for the properties of glutamine(asparagine)ase from Pseudomonas aurantiaca-548. The enzyme is a tetramer having a molecular weight of 148 kD and consisting of 4 identical subunits having a molecular weight of 37 kD. For glutaminase activity, the optimum pH is in the range of 6.

[The nature of functional groups in the active center of antitumor glutamin-(asparagin-)ase].

The effect of two reagents on glutamin (asparagin) ase from Pseudomonas aurantiaca-548 has been studied. 2,3-butanedione which modified arginine residues was ineffective for the inactivation of the enzyme. The enzyme was completely inactivated in the presence of N-ethyl-5-phenylisoxazolium-3'-sulfonate (Woodward's reagent K).

[Relation between the transport of glutamic acid and Escherichia coli resistance to tetracyclines].

The rate of glutamate uptake was shown to decrease while the rate of glutamate export from preloaded cells increased after the resistance to tetracyclines had been induced in the cells of plasmid-bearing Escherichia coli strains. Similar results were obtained with membrane vesicles prepared from the cells induced by the antibiotic and from the non-induced cells. These data imply that the transport channel formed after the induction in the membranes of resistant cells can also function as a mechanism which mediates the active export of glutamate from the cells.

6-diazo-5-oxo-L-norleucine and azaserine as affinity inhibitors of glutamin(asparagin)ase.

Incubation of homogeneous glutamin(asparagin)ase from Pseudomonas aurantiaca with 6-diazo-5-oxo-L-norleucine (DON) and azaserine leads to an almost complete inactivation of the enzyme. The inactivation process in both cases involves the step of reversible binding of the enzyme with the inhibitor into a complex and subsequent modification of the enzyme within this complex. The data on saturation of the enzyme by low concentrations of inhibitors, the protective effect of substrate and its analogs as well as of the competitive inhibitor and product of the enzymatic reaction, L-aspartate, suggest that the modification of functional groups takes place in the enzyme active site.

[Inactivation of microbial glutamin-(asparagin-)ase by azaserine and 6-diazo-5-oxo-L-norleucine].

The effect of substrate analogues on glutamin-(asparagin-)ase from Pseudomonas aurantiaca-548 has been studied. The enzyme was demonstrated to be highly sensitive to the the action of 6-diazo-5-oxo-L-norleucine and azaserine. L-isomers of glutamine, aspartate, glutamate and several other substrate analogues with free alpha-amino groups protected the enzyme against the inhibitory DON effect.

[Thermostabilization of glutamin(asparagin)ase from Pseudomonas aurantica BKMB-548].

In studies on kinetics of thermoinactivation of glutaminase (asparaginase) from Ps. arantiaca BKMB-548 at 50 degrees and pH 7.0 in presence or in absence of L-glutamate the enzyme inactivation was found to obey the first order equation.

[Purification of lipase of microbial origin by silochrome chromatography].

The possibility of purifying lipase from Geotrichum asteroides by chromatography with a modified silochrome used as sorbent has been explored. The paper presents a scheme of adsorption and subsequent desorption of lipase from octylsilochrome which requires that ethylene glycol, Na-deoxycholate and Triton X-100 be used as eluents. Triton, the last in the sequence, eluates the major portion of the enzyme.

[Glutamin(asparagin)ase from Pseudomonas aurantiaca BKMB-548].

A method for isolation of glutamin (asparagin) ase from Pseudomonas aurantiaca BKMB-548 has been developed. The enzyme preparation is homogeneous during polyacrylamide gel electrophoresis (pH 7.5 and 7.

[Effect of the lipid component of the medium on lipase biosynthesis by fungi].

The lipolytic activity of the fungi Aspergillus and Rhizopus was studied on a medium with soybean flour. The lipolytic activity of the Aspergillus fungi was low or absent whereas many of the cultures belonging to the Rhizopus genus possessed the lipolytic activity. The effect of soybean flour components on lipase biosynthesis was studied with Geotrichum asteroides and Rhizopus cohnii AUCMF-597.

[Lipolytic activity of Mycobacterium rubrum cells, immobilized in polyacrylamide gel].

The cells of Mycobacterium rubrum 403 possessing lipolytic activity can be immobilized in polyacrylamide gel. The lipolytic activity of immobilized cells is 20-30 per cent of the activity of free cells. The lipolytic activity of immobilized cells does not changee after they have been used once and then stored at +4 degrees C during 5 months.

[The effect of metal ions on the lipolytic activity of Mycobacterium rubrum and Actinomyces streptomycini].

Hydrolysis of olive oil by intact cells of Mycobacterium rubrum 403 and "acetone" preparations of Actinomyces streptomycini 116 was found to be inhibited by the following ions: Ca2+, Mg2+, Mn2+, Ba2+, Co2+, Cd2+, Cu2+, Zn2+, Fe2+, Fe3+, Ni2+. Olive oil is hydrolyzed by the growing culture of Act. streptomycini 116 only in the presence of bivalent metal ions.