Rate of benyzylpenicillin inactivation in native solutions during extraction]

The constants of benzylpenicillin inactivation in acidified fermentation broth filtrates were different in various filtrate batches. Marked inactivation of the antibiotic in the filtrates immediately after their acidification was observed. Possible losses of the antibiotic due to inactivation under conditions of extraction were estimated.     

Rab35 and glucocorticoids regulate APP and BACE1 trafficking to modulate Aβ production

Chronic stress and elevated glucocorticoids (GCs), the major stress hormones, are risk factors for Alzheimer’s disease (AD) and promote AD pathomechanisms, including overproduction of toxic amyloid-β (Aβ) peptides and intraneuronal accumulation of hyperphosphorylated Tau protein. The latter is linked to downregulation of the small GTPase Rab35, which mediates Tau degradation via the endolysosomal pathway. Whether Rab35 is also involved in Aβ overproduction remains an open question. Here, we find that hippocampal Rab35 levels are decreased not only by stress/GC but also by aging, another AD risk factor. Moreover, we show that Rab35 negatively regulates Aβ production by sorting amyloid precursor protein (APP) and β-secretase (BACE1) out of the endosomal network, where they interact to produce Aβ. Interestingly, Rab35 coordinates distinct intracellular trafficking steps for BACE1 and APP, mediated by its effectors OCRL and ACAP2, respectively. Finally, we demonstrate that Rab35 overexpression prevents the amyloidogenic trafficking of APP and BACE1 induced by high GC levels. These studies identify Rab35 as a key regulator of APP processing and suggest that its downregulation may contribute to stress-related and AD-related amyloidogenesis.Subject terms: Cellular neuroscience, Alzheimer''s disease     

Surface structure of nerve tissue transplants growing in the anterior chamber of the rat eye (electron-microscopic study)

Two different types of the glial envelope are demonstrated around the septal cerebral area grafts (SCAG) and the hippocampal grafts (HG) developing in the anterior eye chamber of the rat during 3-4 months. In the SCAG it is multilayered, consists mainly of modified oligodendrocytes. Processes of the nervous cells perforate the surface of the envelope. In the HG the unilayered glial envelope consists of bodies and processes of the fibrous astrocytes; it is impenetrable for the nervous processes. Since both types of the cellular elements making these envelopes have been described in the norm, it is possible that the differences in the surfaces described are specific for these structures.     

Antibiotic therapy of acute dysentery in children with immunologic deficiency conditions

One hundred children with acute Sonnei and flexneri dysentery were followed up with respect to the infection process and main immunity indices. In 32 children the immunity indices were physiological (group 1) and in 68 children secondary immune deficiency was observed (group 2). The children were treated with aminoglycoside antibiotics and prodigiozan and it was stated that the time of recovery in the children with immune deficiency was longer by 5.2 days as compared to that in the children without immune deficiency. In the children with immune deficiency the combined use of one of the aminoglycosides, prodigiozan and lysozyme, led to a reduction of the host immunological reactivity and recovery within the same periods as those recorded for children with the physiological immunity status. It is recommended to use the antibiotic combination with prodigiozan and lysozyme in the treatment of all the forms of dysentery in children with secondary immune deficiency.     

Microanalytical methods: latex agglutination and immunoenzyme analysis in the diagnosis of meningococcal infection

Modified polystyrene latexes with high adsorption capacity, comparable to that of latexes produced by Difco Laboratories (USA), have been developed in the USSR. Diagnostic latex preparations for the detection of meningococci of serogroups A, C, Y and Haemophilus influenza, type b, prepared on the basis of these new latexes, have shown high specificity and sensitivity in experimental and clinical tests.The latex preparations for the detection of serogroup B meningococci requires further improvement. The use of latex preparations, together with other laboratory methods, in the diagnosis of meningococcal infection has promoted the etiological confirmation of the disease in 84% of cases; this method has proved to be 1.5 times more effective than the bacteriological one and not less sensitive than the enzyme immunoassay, while being more specific.     

Characteristics of dissociation in cultures of Aspergillus brasilense Sp7

Peculiarities of dissociation in the cultures of nitrogen-fixating soil microorganism Azospirillum brasilense have been studied. The possible transfer among colony-morphology variants is established. The relations between variants are described by the following scheme: R in equilibrium with SR----S Electrophoretic analysis of plasmid contents in different variants of Azospirillum brasilense supposes the possible participation of plasmid DNA in the dissociation process in this microorganism.     

Homeostatic reactions of the human body during exposure to 105-day isolation

Biochemical studies of blood (38 parameters) in the course of a 105-day isolation and confinement experiment were performed to assess the status of organs and tissues and some aspects of metabolism in six male volunteers. The results of the study showed that isolation was accompanied by a downward trend in the content of total protein, urea, and uric acid, as well as a decrease in the content of cholesterol and its fractions, whereas the concentration of triglycerides showed a compensatory rise. Creatinine phosphokinase activity increased at the expense of the muscular isozyme. The content of other substances that indirectly characterize the state of muscle tissue??creatinine, magnesium, and serum iron??also increased. Biochemical parameters characterizing the state of the myocardium (cardiac creatinine phosphokinase isozyme, ??-hydroxybutyrate hydrogenase, and aspartate aminotransferase) remained unchanged or decreased. Changes characteristic of hypodynamia were observed. The activity of lactate dehydrogenase tended to decrease, and the activities of total and pancreatic lipase, amylase, and ??-glutamyltransferase also decreased. These changes normalized partly on day 8 of recovery. On the whole, the metabolic trends observed in the test subjects resemble the patterns observed in cosmonauts returning from spaceflights.     

Effect of gentamycin in combination with prodigiozan on the immunological reactivity of the body

The effect of gentamicin sulphate and its combination will prodigiozan on antibody formation in experiments and the levels of the immunobiologic reactivity of patients with purulent inflammatory processes was studied with a purpose of developing rational schemes of antibiotic therapy of infectious diseases. A decrease in the titers of the antibodies to Aeromonas and the number of antibody-forming cells in the spleen was noted on repeated administration of gentamicin to albino mice in a dose of 20 mg/kg. This was prevented by the use of prodigiozan in a dose of 500 micrograms/kg once every 4 days. The use of gentamicin in patients with purulent inflammatory diseases in doses of 40 or 80 mg twice a day for 7--10 days had no significant effect on the titers of IgA, IgG, IgM, lysozyme blood serum levels, serum bactericidal activity and absorption activity of the peripheral blood neutrophils. Still, it induced a marked suppression of the neutrophil digestive capacity as compared to the initial levels, especially on administration of gentamicin in a dose of 40 mg twice a day. An increase in the level of IgM and no suppression of the neutrophil digestive capacity were noted after completion of the therapy in the patients treated with gentamicin administered in a dose of 40 mg twice a day and prodigiozan administered in a dose of 50 micrograms once every 4 days. It is recommended to use prodigiozan in combinaed therapy with gentamicin for correction of the changes in the specific and nonspecific protective forces of the host.     

The dependence of intracellular ATP level on the nutrition mode of the acidophilic bacteria Sulfobacillus thermotolerans and Alicyclobacillus tolerans

The dynamics of the ATP pool in the aerobic spore-forming acidothermophilic mixotrophic bacteria Sulfobacillus thermotolerans Kr1T and Alicyclobacillus tolerans K1T were studied in the course of their chemolithoheterotrophic, chemoorganoheterotrophic, and chemolithoautotrophic growth. It was established that, during mixotrophic growth, the maximum ATP concentrations in the cells of S. thermotolerans Kr1 and A. tolerans K1 were 3.8 and 0.6 nmol/mg protein, respectively. The ATP concentrations in sulfobacilli and alicyclobacilli during organotrophic growth were 2.2 and 3.1 nmol/mg protein, respectively. In the cells of the obligately heterotrophic bacterium Alicyclobacillus cycloheptanicus 4006T, the maximum ATP concentration was several times higher and reached 12.3 nmol/mg protein. During lithotrophic growth, the maximum values of the ATP concentration in the cells of S. thermotolerans Kr1 and A. tolerans K1 were 0.3 and <0.1 nmol/mg protein, respectively; in the cells of the autotrophic bacterium Acidithiobacillus ferrooxidans TFBk, the ATP content was about 60-300 times higher (17.0 nmol/mg protein). It is concluded that low ATP content is among the possible causes of growth cessation of S. thermotolerans Kr1 and A. tolerans K1 under auto- and heterotrophic conditions after several culture transfers.