[Expression of myelin basic protein and glial fibrillary acidic protein genes in human glial brain tumors].

Analysis of the expression of genes encoding myelin basic protein (MBP) and glial fibrillary acidic protein (GFAP) genes in human glial tumors was carried out for determination of the expression specificity of these genes according to tumor types and their malignancy. Low levels of MBP mRNA in astrocytoma specimens of malignancy grades II-IV and significantly higher levels in perifocal zone adjacent to them have been determined by Northern hybridization. Diffuse astrocytomas and anaplastic astrocytomas are characterized mostly by low level of MBP gene expression and high level of GFAP gene expression, but distinct subtypes of diffuse and anaplastic astrocytomas with high level of MBP gene and low level of GFAP gene expression can be also detected that may be the reflection of different oncogenic pathways. Very low levels or even absence of MBP mRNA were revealed in oligodendroglioma and all oligoastrocytomas. Thus, Northern hybridization data are correlated with Serial Analysis of Gene Expression (SAGE). Obtained results show that MBP is nonspecific marker for tumors of oligodendroglial origin, but determination of relative levels of MBP and GFAP mRNAs may be useful for glial tumors recognition. By such a way, these two genes together with previously found by us YKL-40 and TSC-22 can be included into the gene panel for the determination of so called "gene signatures" of brain tumors. However, severe requirements in relation to a clinical value of these "gene signatures" can not be formulated without their verification on plenty of clinical samples of tumors and valid control.

[A new sorbent for concentrating viruses from an aqueous medium]. / Novyi sorbent dlia kontsentratsiï virusiv iz vodnoho seredovyshcha.

Sorption activity was studied of a naturally occurring dispersive mineral saponite towards certain representatives of the families of Picornaviridae and Reoviridae: poliomyelitis type II viruses, Coxsackie B 1 and B 6, monkey disease rotavirus. In increasing rank order in respect of specific sorption activity is naturally occurring bentonite--sodium form of bentonite--naturally occurring saponite. Possible mechanisms of sorption of viruses on the sorbent's surface, related to structural and chemical properties of the mineral are discussed.

[Direct screening of antibiotics-siderophores of bacterial origin]. / Napravlennyi skrining antibiotikov-sideroforov bakterial'nogo proiskhozhdeniia.

Antifungal activity of 275 strains belonging to 15 species of Pseudomonas was studied with using media containing no iron or supplemented with 100 micrograms/ml of FeCl3. 33 per cent of the cultures showed lower activity against phytopathogenic fungi in the presence of iron. Addition of this element did not influence the antifungal activity of phenazin and floroglucin derivatives isolated from Pseudomonas cultures. However, its addition markedly lowered the antifungal effect of some crude antibiotics and fluorescent pigments. A scheme for screening siderophore antibiotics with using Pseudomonas cultures is described.

[Numerical systematics of bacteria of the genus Pseudomonas]. / Numericheskaia sistematika bakterii roda Pseudomonas.

In 290 strains of bacteria belonging to the genus Pseudomonas, 120 morphological and physiologo-biochemical characters were studied and the results obtained thereby were analyzed by the methods of numerical taxonomy using computers. The majority of strains were subdivided into 11 clusters: Ps. aeruginosa (1), Ps. putida (2), Ps. rathonis (5), Ps. syringae (8), Ps. pseudoalcaligenes (9), Ps. maltophilia (10), Ps. acidovorans (11), Ps. testosteroni (12), Ps. mendocina (13), Ps. cepacia (14), Ps. fluorescens (3). The latter cluster included also the strains identified earlier as Ps. aurantiaca, Ps. lemonnieri, Ps. fluoro-violaceus, and Ps. aureofaciens. Three clusters contained strains which could not be identified and probably should be regarded as distinct species. The characteristics have been selected useful for diagnostics of the above Pseudomonas bacteria and the subgroups of Ps. fluorescens.

[Growth and antibiotic formation of bacteria of genus Pseudomonas on media with n-alkanes of low molecular weight]. / Rost i obrazovanie antibiotikov bacteriiami roda Pseudomonas na sredakh s nizkomolekuliarymi n-alkanami

The ability to assimilate n-alkanes form hexane to decane was studied among 495 collection strains and 27 freshly isolated strains belonging to the genus Pseudomonas. All freshly isolated strains and over one third of collection cultures of Ps. aurantiaca grow on mineral media with n-alkanes of low molecular weight, but do not assimilate heavy paraffins. The strains of Ps. aeruginosa, Ps. fluorescens and Ps. putida, isolated from oilbearing soils, and individual collection cultures, belonging to the two latter species, can assimilate both n-alkanes of low molecular weight (C6--C10) and heavy paraffins. Contrary to Ps. aurantiaca, other species of the Pseudomonas genus lose the ability to assimilate n-alkanes of low molecular weight after cultivation on rich organic media. An increase in the concentration of the mixture of low molecular weight paraffins (to 20 per cent by volume) has no toxic effect on the Pseudomonas bacteria whose biomass has a high content of protein and all necessary amino acids. The strains of Ps. aurantiaca produce a highly active antibiotic preparation consisting of floroglucine derivatives on the defined medium with n-alkanes of low molecular weight. The ratio between components of the preparation obtained on the media with n-alkanes and on the optimal organic media is different.