PubMed Health⌕ Search

Biomedical subjects

S N Borkhsenius

Publications and source records attributed to S N Borkhsenius.

At least 19 recordsLinked to original sources
PubMed2003

[Cloning and expression of the Mycoplasma hominis ftsZ for a cell division protein].

A Mycoplasma hominis chromosomal fragment containing the full-length ftsZ gene was cloned and sequenced. Natural expression of this gene was demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) with total RNA. The M. hominis FtsZ protein was shown to differ substantially from its counterparts of two other Mycoplasma species, M. genitalium and M. pneumoniae. The possibility of M. hominis ftsZ expression in Escherichia coli was demonstrated with several bacterial strains. The M. hominis FtsZ protein was isolated from E. coli cells transformed with recombinant plasmids carrying the M. hominis ftsZ gene. Complementation between the E. coli and M. hominis FtsZ proteins was observed in transformants.

Amino Acid Sequence↗
PubMed2001

[Interaction of Mycoplasma with immune system of animals and humans].

Mycoplasmal infections of animals and human belong to latent or chronic ones, being commonly accompanied with immunodeficiency symptoms. The following topics are discussed in this review: 1) a direct influence of mycoplasmas on the immune system cells with an interference and compression of the functional activity of these; 2) influence of mycoplasmas on the immune system via cytokine induction; 3) mitogenes and mitogenic action of mycoplasmas; 4) the role of mycoplasmas in the development of autoimmune processes. Basic host immune response to mycoplasma is presented in diagrams.

Animals↗
PubMed1999

[Cloning and expression of the gene for the mycoplasma key division protein FtsZ in Escherichia coli].

Gene ftsZ responsible for division of bacterial cells was revealed in most prokaryote groups. A 520-bp fragment of the ftsZ gene was amplified on the template of A. laidlawii DNA using degenerate primers. This fragment was sequenced and served as a hybridization probe for cloning of the full-sized copy of the A. laidlawii ftsZ gene. The amplified fragment was cloned in a pGEX3X vector and expressed in E. coli cells. Polyclonal antibodies derived from the chimeric polypeptide containing a fragment of A. laidlawii FtsZ protein interacted only with the A. laidlawii protein with molecular mass of 40 kDa. Comparison of nucleotide sequences of the ftsZ-gene region of A. laidlawii and other bacterial species showed that they were highly homologous in A. laidlawii, E. coli, and Bac. subtilis, while low homology was revealed between the A. laidlawii sequence and those of the members of the genus Mycoplasma. Analysis of the ftsZ-gene nucleotide sequences is suggested as a means to study the evolutionary relatedness of prokaryotes.

Acholeplasma laidlawii↗
PubMed1992

[Tubular structures in Mycoplasma gallisepticum and the localization of a tubulin-like protein].

In all the strains of M. gallisepticum investigated, a protein with apparent molecular weight 40 kDa was revealed by immunoblotting with polyclonal anti-calf brain tubulin antibodies and monoclonal anti-chicken alpha-tubulin antibodies. In other 8 investigated Mycoplasma species no positive reactions with the same antibodies were found. The M. Gallisepticum cells were examined under electron microscope on fine serial sections and on some sections going at different angles to the long cell axis. Undermembrane system of tubules was revealed and the intracellular pattern of the tubular structures were reconstructed. The immunoelectron microscopic data suggest that tubulin-like protein may be included into the structures.

Acholeplasma laidlawii↗
PubMed1992

[Molecular biological differences between strains of Mycoplasma gallisepticum].

Differences in virulence of two Mycoplasma gallisepticum strains, S6 and A5969, are confirmed in experiments with chickens. Macromolecular discrepancies detected between these two strains are concerning the genomic size, electrophoretic spectra of DNA and proteins. Cross immunoblotting data with polyclonal and monoclonal antibodies reveal major immunogens of protein nature in both the strains. Homologous proteins with different electrophoretic mobility are detected in other four M. gallisepticum strains. A possible participation of these proteins of M. gallisepticum in adhesion to the host cells is discussed.

Animals↗
PubMed1987

[Mycoplasmas].

Structural peculiarities of the mycoplasmas--the smallest prokaryotic organisms--are reviewed, in addition to their complicated relationships with the eukaryotic cells and with the whole organisms of plants and animals.

Animals↗
PubMed1987

[The Mycoplasma genome].

A review is presented of the available data on the nature of chromosomal and extrachromosomal DNA of Mollicutes (mycoplasmas)--the smallest and simplest procaryotic organisms.

Base Sequence↗
PubMed1987

[Detection and identification of Mycoplasma infections by DNA hybridization].

Infection of cell cultures by mycoplasmas can be detected by hybridization of the DNA of suspected cell cultures with recombinant plasmids containing fragments of the mycoplasma DNA. The test is very sensitive and allows detection of as little as 1 ng of mycoplasmal DNA, roughly equivalent to the DNA amount of 10(6) mycoplasmas. This approach turns out to be effective for detection and identification of mycoplasmas in clinical material, plant and insect tissues. A set of DNA probes for detection of mycoplasmas infecting cell cultures by dot hybridization has been constructed. This set consists of specific DNA probes and universal DNA probe. Recombinant plasmids, pAl32, pMa13, pMh9, containing specific DNA fragments of Acholeplasma-laidlawii, Mycoplasma arginini, Mycoplasma hominis (the prevalent mycoplasma contaminants of home cell cultures) are species-specific DNA probes. Recombinant plasmid pMg16 containing rRNA genes of Mycoplasma gallisepticum is the universal DNA probe for detection of any mycoplasma (or any prokaryote) contaminations. These two classes of DNA probes may be considered as complementing each other. These 32P labeled probes do not hybridize with eukaryotic DNA. The set of DNA probes allows not only to detect infection of cell cultures by mycoplasmas but also to identify the species of mycoplasmas and to evaluate the multiplicity of mycoplasma infection.

Animals↗
PubMed1979

[Replicon size and rate of DNA replication in the macronucleus of Tetrahymena pyriformis].

The size of replication units (or replicons) measured in Tetrahymena pyriformis GL macronuclear DNA reaches 20--30 microns, according to the two independent methods: DNA fiber autoradiography, and alkaline isokinetic sucrose gradient centrifugation. The synthesis of new DNA fragments--replicons and their subsequent assembly are separated by time intervals (30 min). The rate of DNA synthesis for one fork averaged 0.6--0.7 microns/min. These data were obtained for cells of cultures being both in the expotential phase of growth, and those synchronized by starvation-refeeding. The generation time of T. pyriformis cells, calculated by the increase of the part of labeled nuclei, is almost 2 hours; the synthesis lasts 1 hour. Total amount of replication units in polyploid (polygenomic) Tetrahymena macronucleus is about 3000. Their initiation during S-period is presumably asynchronous.

Animals↗
PubMed1979

[Characteristics of DNA in vegetative specimens of Bursaria truncatella].

DNA from Bursaria truncatella was isolated and purified by conventional methods. The DNA base content was calculated from both centrifugation in CsCl and melting. The GC-content is 24%. In CsCl density gradient 3H-DNA is banded as a single peak at a range 1.682--1.688 g/cm3 with the maximum at 1.684 g/cm3. The Tm in 0.12 M FB (pH 6.8) was 79 degrees C. About 50% of DNA seems to be represented by highly repetitive sequences, another 50% being made of single-copy sequences (a preliminary data on DNA-DNA reassotiation kinetics). For the estimation of the molecular weight of DNA, the cells were lysed immediately before the centrifugation, at the surface of the alkaline isokinetic sucrose gradient solution. Two components of DNA were detected with molecular weights 10-10(6) and 100-10(6) daltons. It is likely that these two components belong to the macronuclear DNA, because according to cytophotometrical evidence the DNA content in the macronucleus of B. truncatella is 2500 times as much as that in its micronucleus.

Animals↗
PubMed1975

Bouyant density of the DNA of sea urchin embryos at different stages of development.

Preparations of high-molecular nuclear DNA were obtained from embroys of the sea urchin Strongylocentrotus droebachiensis at the stages of early and late blastula, gastrula, and pluteus. In an equilibrium cesium chloride density gradient, these preparations exhibit a single narrow symmetrical band at 1.695-1.703 g/cm3 with a maximum at l.699 plus or minus 0.001 g/cm3 and do not contain satellite components. Nuclear DNA of embroys at the stage of 128 blastomeres (morula), which has a molecular weight of 10-6, exhibits a single broad symmetrical band at 1.690-1.710 g/cm3 with a maximum at 1.699 g/cm3 in a density gradient. Fragments of blastula and pluteus DNA obtained as a result of treatment with ultrasound give an analogous distribution. Preparations of total DNA of unfertilized ovicells, total DNA of spermatozoids, and cytoplasmic DNA of the morula contain satellite components with buoyant densities of 1.717-1.725 g/cm3 side by side with the main band.

Animals↗