[AccBSI - a novel restriction endonuclease from Acinetobacter calcoaceticus BS].

The recognition site of a new restriction endonuclease from Acinetobacter calcoaceticus BS was determined. This is a nonpalindromic sequence. AccBSI restrictase cleaves DNA chains in the middle of the recognition sequence; therefore, ligation of its digestion fragments restored AccBSI recognition sites and generated palindromic sequences recognized by SacI and SacII restrictases.

Immunocytochemical evidence for a stepwise assembly of Balbiani ring premessenger ribonucleoprotein particles.

In the active Balbiani ring (BR) genes of the dipteran Chironomus tentans, the assembly of a specific pre-mRNP particle can be analyzed in situ, and the incorporation of hnRNP proteins into the nascent pre-mRNP can be directly visualized by immunoelectron microscopy. In the present study we have shown that hrp36, one of the major hnRNP proteins in Chironomus tentans, is continuously added to the nascent BR pre-mRNP particle throughout transcription and is localized along the entire BR RNP fiber. Interestingly, hrp36 becomes concealed during the structural transition that occurs during the formation of the mature BR RNP particle.

Macromolecular substructure in nuclear pore complexes by in-lens field-emission scanning electron microscopy.

Scanning electron microscopy (SEM) has produced a wealth of novel images that have significantly complemented our perception of biological structure and function, derived initially from transmission electron microscopy (TEM) information. SEM is a surface imaging technology, and its impact at the subcellular level has been restricted by reduced resolution in comparison with TEM. Recently, SEM resolution has been considerably improved by the advent of high-brightness sources used in field-emission instruments (FEISEM) which have produced resolution of around 1 nm, virtually equivalent to TEM "working resolution.

Distribution of the total unsaturation in lipid components of plasma as a new differential diagnostic method in clinical analysis.

Using ozonization and thin-layer chromatographic methods we determined the qualitative and quantitative correlation of unsaturation distribution (UD) in individual fractions of blood plasma lipids in children suffering from insulin-dependent diabetes mellitus (IDDM). The research was aimed at elucidation of biochemical criterion of the degree of metabolic disorders in children with IDDM and at development of methods for quantitative assessment of such disorders. Twenty children were examined during the compensation stage (group 1), and twelve during decompensation with ketoacidosis (group 2).

A protein of the SR family of splicing factors binds extensively to exonic Balbiani ring pre-mRNA and accompanies the RNA from the gene to the nuclear pore.

We report on the molecular cloning and intracellular localization of a heterogeneous nuclear ribonucleoprotein (hnRNP), Ct-hrp45, one of the major components of pre-mRNP particles in Chironomus tentans. It is shown that hrp45 belongs to the SR family of splicing factors and exhibits high sequence similarity to Drosophila SRp55/B52 and human SF2/ASF. The distribution of hrp45 within the C.

Immunosorbent for IgG apheresis: an in vitro study.

We obtained anti-IgG Sepharose-an immunosorbent with sheep monospecific polyclonal antibodies against human IgG-for extracorporeal removal of human IgG. Appropriate conditions for effective usage of the immunosorbent were chosen. Binding capacity and selectivity of anti-IgG Sepharose were determined and compared with the corresponding properties of other sorbents for IgG apheresis; these properties appeared to be acceptable for immunoapheresis procedures.

[The chemical interaction of tadpoles of the common frog Rana temporaria L. with conspecific and heterospecific anuran tadpoles].

In double-choice experiments the behavioural reactions of Rana temporaria tadpoles to con- and heterospecific chemical cues of anuran tadpoles were studied. It was shown that they have not reacted to heterospecific chemical signals but were attracted by co-specific ones. Besides, Rana temporaria tadpoles do not show chemical guided sibling-reaction, saying that the sibs' cues were not preferable.

The single-stranded DNA end binding site of p53 coincides with the C-terminal regulatory region.

p53 is a transcription factor that binds double-stranded (ds) DNA in a sequence-specific manner. In addition, p53 can bind the ends of single-stranded (ss) DNA. We previously demonstrated that ssDNA oligonucleotides interact with the C-terminal domain of p53 and stimulate binding to internal segments of long ssDNA by the p53 core domain.

RNP export is mediated by structural reorganization of the nuclear pore basket.

Messenger RNA leaves the cell nucleus as ribonucleoprotein (RNP) particles. The nucleocytoplasmic translocation of the particles takes place through the nuclear pore complex (NPC) and includes two steps: binding to the NPC and transit through its central channel. The NPC basket is a fishtrap-like component of NPC facing the nucleoplasm.

Identification of two RNA-binding proteins in Balbiani ring premessenger ribonucleoprotein granules and presence of these proteins in specific subsets of heterogeneous nuclear ribonucleoprotein particles.

Balbiani ring (BR) granules are premessenger ribonucleoprotein particles (RNPs) generated in giant chromosomal puffs, the BRs, in the larval salivary glands of the dipteran chironomus tentans. Monoclonal antibodies were raised against nuclear proteins collected on a single-stranded-DNA-agarose affinity column, and two of them were used to identify RNA-binding proteins in BR granules. First, in Western blots (immunoblots), one of the antibodies recognized a 36-kDa protein and the other recognized a 45-KDa protein.

[Intraoperative radiation therapy: its technological support, potentials and prospects].

The authors' experience with intraoperative radiotherapy (IORT) in 129 patients with a tumorous process at various sites has demonstrated that in most clinical events, single radiation doses of 10-20 Gy is insufficient to have a persistent local effect and requires additional pre- or postoperative remote irradiation. The use of IORT as a single component of radiation exposure does not lead to significant radiation damages to normal tissues. When IORT is combined with remote irradiation (the latter using doses of 30-60 Gy), 30% of patients develop radiation-induced normal tissue lesions.

A pre-mRNA-binding protein accompanies the RNA from the gene through the nuclear pores and into polysomes.

In the larval salivary glands of C. tentans, it is possible to visualize by electron microscopy how Balbiani ring (BR) pre-mRNA associates with proteins to form pre-mRNP particles, how these particles move to and through the nuclear pore, and how the BR RNA is engaged in the formation of giant polysomes in the cytoplasm. Here, we study C.

Accessing nuclear structure for field emission, in lens, scanning electron microscopy (FEISEM).

Scanning electron microscopy (SEM) has had a shorter time course in biology than conventional transmission electron microscopy (TEM) but has nevertheless produced a wealth of images that have significantly complemented our perception of biological structure and function from TEM information. By its nature, SEM is a surface imaging technology, and its impact at the subcellular level has been restricted by the considerably reduced resolution in conventional SEM in comparison to TEM. This restriction has been removed by the recent advent of high-brightness sources used in lensfield emission instruments (FEISEM) which have produced resolution of around 1 nanometre, which is not usually a limiting figure for biological material.

[The influence of C-reactive protein and its subunits on the cytotoxic effect of tumor necrosis factor-alpha in relation to L929 fibroblasts].

A study was made of the ability of purified human C-reactive protein (CRP) in pentameric (pCRP) and subunit (sCRP) form to induce the production of tumour necrosis factor alpha (TNF-alpha) in macrophage-like cell line P388D1, as well as the combined effects of CRP and recombinant human TNF-alpha on the proliferation of L929 cell line. Both pCRP and sCRP induced TNF production by P388D1 cells, pCRP was inhibitory per se for L929 cells, while sCRP was not, when present in cultures for 72 h without actinomycin D (AD). In the presence of AD, sCRP was inhibitory as well, even when the period of incubation was reduced to 18 h.

[Visualization of DNA segments, interacting with reactive oligonucleotide derivatives in interphase nuclei and metaphase chromosomes].

Reaction of (pdT)16 derivatives, bearing 4-(N-2-chloroethyl-N-methylamino)benzylphosphamide group on its 5' end and biotin on its 3' end with DNA in interphase nuclei and metaphase chromosomes has been investigated by fluorescence and electron microscopy. The result obtained evidence that in interphase nuclei DNA in active chromatin (nucleolus) is the most available for specific modification. In metaphase chromosomes the modified DNA regions are situated on the surface of chromosome.

[Natural amino acids as effective stimuli evoking chemoreceptor-directed behavior in anuran tadpoles].

The behavioral reactions of tadpoles of four anuran species, inhabiting Moscow Region (Rana temporaria L., R. lessonae Cam.

p53 binds single-stranded DNA ends through the C-terminal domain and internal DNA segments via the middle domain.

We have previously reported that wild-type p53 can bind single-stranded (ss) DNA ends and catalyze renaturation of ss complementary DNA molecules. Here we demonstrate that p53 can also bind to internal segments of ss DNA molecules via a binding site (internal DNA site) distinct from the binding site for DNA ends (DNA end site). Using p53 deletion mutants, the internal DNA site was mapped to the central region (residues 99-307), while the DNA end site was mapped to the C-terminal domain (residues 320-393) of the p53 protein.

[The chemical interaction of tadpoles of the frog Rana arvalis Nilss. with conspecific and heterospecific anuran tadpoles].

In double-choice experiments the tadpoles of Rana arvalis were offered chemical cues of con- and heterospecific tadpoles in different combinations. It was shown that they are capable of distinguishing these signals. The cues of Bufo bufo and Rana lessonae larvae induced a clear reaction of attraction, whereas those of Rana temporaria did not cause any visible behavioral response.

Assembly and disassembly of spliceosomes along a specific pre-messenger RNP fiber.

Transcriptionally active Balbiani ring (BR) genes in the salivary glands of the dipteran Chironomus tentans were studied by immunoelectron microscopy to establish the distribution of spliceosome components along a specific pre-messenger ribonucleoprotein (pre-mRNP) fiber. The BR genes are 35-40 kb in size with three introns close to the 5' end and one close to the 3' end; a very large middle portion lacks introns. As a rule the 5' introns are spliced concomitant with transcription in the promoter proximal third of the gene, while the 3' intron is spliced post-transcriptionally.

[Interaction of transcortin with human syncytiotrophoblast].

Interactions of transcortin (corticosteroid-binding globulin, CBG) variants, nCBG and rCBG, present in the blood of pregnant women, and microvesicular fraction of the brush border membrane of human placental syncytiotrophoblast at 23 +/- 2 degrees C were studied. Interaction of nCBG in complex with a steroid with each of the two types for specific binding was found associated with transmembranous transfer of glycoprotein. Interaction of rCBG with binding sites of both types did not involve subsequent glycoprotein transfer through the membrane.

[Distribution of the total quantity of fatty acid double bonds in lipid components of the blood in children with diabetes mellitus].

Children suffering from insulin-dependent diabetes mellitus (IDDM) were examined for unsaturation, that is, total quantity of double bonds in individual fractions of blood serum lipids was assessed. Lipid fractions were isolated by thin-layer chromatography. Unsaturation was assessed by ozonation method.