Functionalized polyolefin synthesis using [P,O]Ni catalysts.

Nickel olefin polymerisation catalysts containing bulky phosphino-enolate ligands are shown to give methyl methacrylate end-functionalized polyolefins.

Persistence and multiplication of obligate anaerobe bacteria in amebae under aerobic conditions.

After co-cultivation of Mobiluncus curtisii, an obligate non-sporeforming anaerobe, with free living amebae from the Acanthamoeba spp. under aerobic conditions, internalization, multiplication and persistence of bacterial cells were established for at least 4-6 weeks. Under the same conditions and media without viable amebae, the cells of M. curtisii did not replicate and died in 4-7 days. The infection of amebae occurred with 10 to 100 bacteria per ml of co-cultivation media. In 7-14 days the amount of bacterial cells increased to 1x10(5)-1x10(6) CFU/mL. Electron microscopic examinations revealed bacteria within vacuoles in the amebae and intracellular replication. These results suggest a previously undescribed mechanism for spread, replication and persistence of obligately anaerobe bacteria in the environment and new possible sources, reservoirs and transfer mechanisms of infections caused by obligate anaerobe bacteria.

[Design of a chromosomal DNA probe species specific for Yersinia pestis]. / Konstruirovanie vidospetsifichnogo dlia Yersinia pestis khromosomnogo DNA-zonda.

A 14.8 kb DNA fragment from the chromosome of Yersinia pestis TWJ was cloned and the restriction map constructed. The fragment designated as T16 and its subfragments were tested in dot-hybridization with strains of Yersinia genus and other members of Enterobacteriaceae. A species-specific DNA probe (designated MK) was constructed on the basis of the T16 fragment. As judged from restriction analysis, blot-hybridization experiments and, partially, sequencing, significant homology exists between the MK DNA probe and this one developed by Bardarov et. al. (1990). A repeated sequence in two copies was discovered in the MK fragment.

A rapid coagglutination test for the detection and serogrouping of Legionellae.

The applicability of coagglutination for the rapid detection and serogrouping of Legionellae has been investigated. The coagglutination reaction is carried out with the aid of self-made preparations of protein A containing staphylococci, sensitized with specific antibodies against the antigens of L. pneumophila (serogroups I to 6), L. bozemanii and L. micdadei. Preliminary heating of Legionella suspensions at 100% C for 15 min was used to prevent cross coagglutination reactions and ensure greater safety of laboratory personnel during the performance of the test. The results obtained demonstrate a high specificity of coagglutination. With the aid of the coagglutination reactions it has been shown that L. pneumophila strains isolated in Bulgaria belong to serogroup I. The coagglutination method is characterized by its rapidity, simplicity and feasibility. It is a useful and convenient means for the rapid detection and serogrouping of Legionellae.

[Directly magnified tomography in the x-ray diagnosis and classification of changes in the sella turcica in intrasellar adenomas]. / Direktno uvelichenata tomografiia pri rentgenovata diagnoza i klasifikatsiia na promenite v sella turcica pri intraselarnite adenomi.

An original method of simultaneous directly magnified tomography of sella turcica (proposed by A. Tomov) was applied in X-ray diagnosis of intrasellar tumors. The authors proposed their own classification of the osseous changes, caused by the development of the intrasellar adenomas on the base of J. Hardy and on the base of the tomographic X-ray signs. The greater number one-moment tomographic images - directly magnified present far better the small alterations in the sellar structures.

Lytic activity of Bdellovibrio bacteriovorus against bacteria of the family Legionellaceae.

A lytic activity of Bdellovibrio bacteriovorus strains 6-5-S and 12 was found to be present, against representatives of three Legionella species: Legionella pneumophila-strains Knoxville 1 (serogroup 1), Togus 1 (serogroup 2), Bloomington 2 (serogroup 3) and Los Angeles 1 (serogroup 4); Legionella micdadei-strain Tatlock; Legionella bozemanii-strain Wiga, as well as against strains of Legionella pneumophila isolated in Bulgaria-Draginovo 1, 2, 3-belonging to serogroup 1. It is suggested that B. bacteriovorus participates in the self-purification of the environment from legionellae.

Isolation of Legionella pneumophila in Bulgaria.

Microorganisms have been isolated from water samples obtained from a small warm mineral lake. The growth, staining, biochemical and antigenic properties of the microorganisms suggest that they belong to legionella pneumophila serogroup 1. This is the first isolation of Legionella in Bulgaria. The necessity of careful search for legionellosis in this country was underlined.

Specific staining of bacilli by means of immuno-indian-ink method and immunofluorescent method.

The possibilities for identification of B. anthracis are investigated by means of the Immuno-Indian-ink method (IIIM) and the immunofluorescent method (IFM) in their direct and indirect modifications. The specifity of sera against noncapsulated cells of B. anthrasis increases by their adsorption with antigenically related strains of B. cereus as their vegetative cells and spores are killed beforehand with performic acid. Repeated uses of the bacillus suspension for adsorption is possible by treating it with hydrochloric acid in order to restore its antigenic properties. The adsorbed sera against noncapsulated cells of B. anthracis in the direct and indirect modifications of IIIM and IFM stain specifically the 19 investigated B. anthracis strains but none of the 152 strains of saprophytic bacilli. In addition to that the possibility for differentiation of B. anthracis from saprophytic bacilli is established also by combination of cultivation on selective medium, facilitating the capsule formation of B. anthracis with IIIM and IFM, performed with sera against capsule antigens of the anthrax agent.