Specific DNA probe for detecting Legionella pneumophila

A fragment of the gene for cytolysin has been cloned. The product of the gene has been earlier identified as an immunoserological marker of Legionella pneumophila. Clones were selected by immunodetection of cytolysin gene product expression. An EcoRI 3.8 kb fragment of the genomic DNA from Legionella pneumophila strain Philadelphia-1 was used as a DNA probe that hybridized with the bacterial colonies of 20 Legionella pneumophila strains but not with the colonies of 10 other Legionella species or 8 other bacterial genera. The cloned fragment has been shown to be unique for Legionella pneumophila. The region of homology is suggested to be longer than a possible dimension of the cytolysin gene.     

Investigation of the Hydrolytic Stability of the HLDF-6-AA Antitumor Peptide by the Method of Accelerated Aging

Russian Journal of Bioorganic Chemistry - The HLDF-6 hexapeptide corresponded to the 41–46 (TGENHR) fragment of the Human Leukemia Differentiation Factor (HLDF) and exhibited a wide spectrum...     

Synthesis of O-substituted 6-oximes of 16alpha,17alpha-cyclohexanopregn-4-en-3,6,20-triones containing a tritium label at the 1,2-position

6-O-(3-Methoxycarbonylpropyl)- and 6-O-(3-carboxypropyl)oximes of 16 alpha,17 alpha-cyclohexanopregn-4-ene-3,6,20-trione labeled by tritium in position 1,2 were synthesized. When using homogenous catalysts, the molar radioactivity of the resulting preparations was 1.5-1.7 PBq/mol.     

Structure of a mutant EF-G reveals domain III and possibly the fusidic acid binding site

The crystal structure of Thermus thermophilus elongation factor G (EF-G) carrying the point mutation His573Ala was determined at a resolution of 2.8 A. The mutant has a more closed structure than that previously reported for wild-type EF-G. This is obtained by a 10 degrees rigid rotation of domains III, IV and V with regard to domains I and II. This rotation results in a displacement of the tip of domain IV by approximately 9 A. The structure of domain III is now fully visible and reveals the double split beta-alpha-beta motif also observed for EF-G domain V and for several ribosomal proteins. A large number of fusidic acid resistant mutations found in domain III have now been possible to locate. Possible locations for the effector loop and a possible binding site for fusidic acid are discussed in relation to some of the fusidic acid resistant mutations.     

The synthesis of <Emphasis Type="Italic">O</Emphasis>-substituted 3-oximes of 6α -methyl-16α,17α-cyclohexanopregn-4-ene-3,20-diones tritium-labeled in the 1,2-position

1,2-Tritium-labeled 3-(O-carboxypropyl)- and 3-(O-carbomethoxypropyl)-oximes of 6α-methyl-16α,17α-cyclohexanopregn-4-ene-3,20-diones were obtained by the homogeneous catalytic hydrogenation of 1,2-dehydroprecursors with gaseous tritium and the subsequent separation of the resulting mixtures by HPLC. The specific radioactivities of 50–55 Ci/mmol were prepared using tris-(triphenylphosphine)-rhodium chloride.     

Kinetics of Semax penetration into the brain and blood of rats after its intranasal administration

The radioactive peptide analogue Semax corresponding to the ACTH(4-10) sequence (Met-Glu-His-Phe-Pro-Gly-Pro) with a molar radioactivity of 56 Ci/mmol labeled with tritium at the C-terminal Pro was prepared. The labeled peptide was used for studying the kinetics of Semax penetration into rat brain and blood after its intranasal administration (50 microg/kg, 20 microl of solution) to nonbred white rats of body mass 200-250 g. It was demonstrated that 0.093% of the total introduced radioactivity per gram can be found in the rat brain 2 min after the administration, 80% of this radioactivity belonged to Semax, and the rest, to its metabolites. The peptide undergoes rapid enzymatic degradation, with the tripeptide Pro-Gly-Pro prevailing in biological samples relative to the total content of Semax and its metabolites.     

Insulin resistance and type 2 diabetes are not related to resistin expression in human fat cells or skeletal muscle.

Resistin is secreted by rodent fat cells and was recently postulated to be an important link between obesity and insulin resistance. We examined Resistin gene expression with real-time RT-PCR in human isolated fat cells, adipose tissue, and muscle from 42 individuals of varying degrees of overweight and who had normal insulin sensitivity or were insulin-resistant or Type 2 diabetic. Resistin was not expressed in human muscle nor was it expressed in most human isolated fat cells or intact biopsies. No difference was found between normal, insulin-resistant, or Type 2 diabetic samples. However, a very low but specific Resistin expression could be demonstrated in isolated fat cells and intact adipose tissue from some individuals (n = 3 and n = 4, respectively). There was no evidence for the expression of splice variants in the human samples. Thus, Resistin does not seem to be an important link to insulin resistance and Type 2 diabetes in human.     

Structural-functional study of glycine-and-proline-containing peptides (Glyprolines) as potential neuroprotectors

A synthetic scheme for preparation of (Gly-Pro) _n , (Pro-Gly) _n (n = 2, 3), and (Pro-Gly-Pro) _n (n = 1, 2) peptides was elaborated. The effect of the synthesized peptides and the Gly-Pro and Pro-Gly dipeptides on survival of cultured cells of PC12 rat pheochromocytoma was studied under the conditions of oxidative stress induced by brief incubation of the cells with hydrogen peroxide. Peptides of the general formula (Gly-Pro) _n and the Pro-Gly-Pro peptide at a concentration of 0.2–100 μM were shown to decrease the number of damaged cells. The Gly-Pro peptide was the most active and decreased the number of damaged cells by 49% on average at a concentration of 100 μM.