[Nucleic acid synthesis and spatial organization of DNA in the presence of heparin and the quaternary ammonium salt of the conidin oligomer-25]. / Sintez nukleinovykh kislot i prostranstvennaia organizatsiiaDNK v prisutstvii geparina i chetvertichnoi ammoniinoi soli oligomera-25 konidina.

A comparative study of polyconidin effects in the replicative and transcription activity of hepatocyte DNA in intact animals, and on peculiarities of spatial organization DNA in the DNA complex with oligomer-25 conidin was carried out. It was shown that polyconidin binding to DNA results in "cross-linking". This process is accompanied by formation of liquid-crystalline dispersion without abnormal optical activity. Liquid crystals possess high density packing of DNA molecules complexed with quaternary ammonium salt of oligomer-25 conidin. The addition of heparin to liquid-crystalline dispersions or phases, destroys the structure of the DNA complex with quaternary ammonium salt of oligomer-25 conidin. As a result "free" DNA molecules appear, they form the cholesteric liquid-crystalline phase. An increase in transcription activity and synchronization of DNA synthesis in hepatocyte was demonstrated. A correlation between chromatin modification and biological activity of chromatin after formation of the DNA--oligomer-25 conidin complex is proposed.

[Some observations on the mechanism of bactericidal activity of Tween 80 on mycobacteria].

In 0.1% Tween 80 aqueous solution or in 0.1% Tween 80-containing saline (0.9% NaCl aqueous solution), Mycobacterium smegmatis strain Jucho bacteria were alive for 3 days, whereas, in 0.1% Tween 80-containing phosphate buffer solution (pH 7.1), the bacteria died rapidly. Since it was shown previously that M. smegmatis is one of the mycobacteria most susceptible to Tween 80 (Tsukamura, M.: Kekkaku 63: 695-699, 1988), the 0.1% Tween 80 aqueous solution or 0.1% Tween 80-containing saline may be used for suspending mycobacteria in order to prevent the clumping. Incorporation of 32P-ortho-phosphate to the nucleic acid fraction was most markedly inhibited by the presence of 0.5% Tween 80 in 0.067 M phosphate buffer solution (pH 7.1). The finding shows that Tween 80 inhibits directly or indirectly the synthesis of nucleic acids. Tween 80 was not bactericidal in an aqueous solution but acted bactericidally in the co-existence of phosphate, and such bactericidal activity was completely diminished by adding an ammoniacal nitrogen compound (Tsukamura, M.: Medicine and Biology (Tokyo) 96: 159-161, 1978). These findings suggest that Tween 80 does not simply act as a detergent but interferes with some metabolic way in the synthesis of nucleic acids.

Sequence-controlled polymers.

Sequence-controlled polymers are macromolecules in which monomer units of different chemical nature are arranged in an ordered fashion. The most prominent examples are biological and have been studied and used primarily by molecular biologists and biochemists. However, recent progress in protein- and DNA-based nanotechnologies has shown the relevance of sequence-controlled polymers to nonbiological applications, including data storage, nanoelectronics, and catalysis. In addition, synthetic polymer chemistry has provided interesting routes for preparing nonnatural sequence-controlled polymers. Although these synthetic macromolecules do not yet compare in functional scope with their natural counterparts, they open up opportunities for controlling the structure, self-assembly, and macroscopic properties of polymer materials.

Measuring synthesis rates of nitrogen-containing polymers by using stable isotope tracers.

The major N-containing polymer compounds in the body include protein, RNA, and DNA. The endogenous gastrointestinal secretions as well as the portal-drained visceral and peripheral immune responses are basic physiological functions. Elevated endogenous secretions and immune activities, as affected by developmental stages, diets, and management factors, decrease the availability of dietary nutrients for peripheral muscle synthesis and deposition. Measurements of in vivo protein, RNA, and DNA synthesis rates associated with the viscera, peripheral immune cells, and skeletal muscles should, in principle, be the sensitive biochemical and cellular endpoints for studying factors affecting nonruminant nutrition, metabolism, and growth. The selection of stable isotope tracers for precursors, routes of tracer delivery, and mass spectrometric analyses of tracer enrichments are the major methodological considerations. To measure in vivo protein, RNA, and DNA synthesis rates, oral feeding with heavy water (2H2O), and continuous infusion of [U-13C]glucose and [15N]Gly intravenously for labeling the sugar moieties ribose and deoxyribose and de novo purine base synthesis have been established. Flooding doses of tracer Phe, for example, L-[ring-2H5]Phe, via the i.p. route are reliable and cost-effective for measuring in vivo protein synthesis rates, especially for the viscera in small nonruminants. Therefore, measurements of the major N-containing polymer synthesis rates in the viscera, the peripheral immune cells, and muscles through oral feeding with 2H2O and/or i.p. flooding doses of Phe tracers are the emerging tools for studying nonruminant nutrition, metabolism, and growth under research and field test conditions.

Origin of life: consideration of alternatives to proteins and nucleic acids.

Starting with relatively simple, non-hydrolyzable compounds in aqueous solution, entirely spontaneous condensations give rise to polymers that contain purines, pyrimidines, amino acids, coenzymes, lipid components and even phosphate. The presence of certain lipid micelles allows significant product formation at millimolar substrate concentrations. The first step involves formation of a Michael adduct from alpha-beta-unsaturated carbonyl compounds and various nucleophiles. Polymerization of these adducts occurs via sequential Knoevenagel condensations. All reactions take place readily at temperatures below 45 degrees. The polymers can act as macromolecular catalysts as evidenced by hydrolytic activity. The purines and pyrimidines in the polymers appear to be capable of both base pairing and stacking interactions with ribonucleic acids. Specific examples of potential alternatives to base pairing are presented. These results are discussed from the standpoint of the spontaneous development of reproducing molecules. Proteins and nucleic acids may be evolutionary developments which have displaced earlier biopolymers.

Complement-mediated killing of porphyromonas gingivalis 381 by the immunoglobulin G induced by recombinant 40-kDa outer membrane protein.

Porphyromonas gingivalis has been implicated as an important pathogen in severe adult periodontitis. We have previously cloned a 40-kDa outer membrane protein from P. gingivalis 381 and succeeded in producing sufficient quantities of the recombinant protein (r40-kDa OMP). r40-kDa OMP has been the subject of considerable interest to us as a possible vaccine candidate. To understand the role of anti-r40-kDa OMP antibody in the host defense mechanisms against P. gingivalis, we examined the involvement of a rabbit antibody against r40-kDa OMP (r40-kDa OMP Ab) to an in vitro complement-mediated bactericidal assay for P. gingivalis 381. By measuring the absorbance values in order to assay the surviving bacteria, we found significant anti-P. gingivalis activity of r40-kDa OMP Ab when guinea pig complement was present. Using affinity-purified immunoglobulin G of r40-kDa OMP Ab (IgG-r40-kDa OMP), we demonstrated that the IgG contributed to anti-P. gingivalis activity in the antibody-complement system. This was effected by measuring the incorporation of tritiated thymidine into newly synthesized nucleic acids. Finally, we confirmed the cell lysis of P. gingivalis 381 exposed to IgG-r40-kDa OMP in the presence of complement sources in a radioactive bactericidal assay using bacteria labeled with [14C]sodium acetate. Assembling the data from experiments using component-deficient complements, we concluded that IgG-r40-kDa OMP was related to the killing of P. gingivalis 381 by mediation in the complement activated through both the classical and the alternative pathways.

Effects of antimetabolites on the adhesion of an estuarine Vibrio sp. to polystyrene.

The effect of various metabolic inhibitors and antibiotics on the adhesion of an estuarine bacterium, Vibrio proteolytica, to polystyrene was investigated. Cells were either exposed to the substratum and the antimetabolite simultaneously or grown in the presence of a 25% MIC and presented the substratum in the absence of the antimetabolite. Based on the response elicited, these inhibitors could be divided into three classes: (i) those that had little or no effect on adhesion (fluorodeoxyuridine and nalidixic acid); (ii) those that only inhibited adhesion after growth at the 25% MIC (ampicillin, oxacillin, and streptomycin); and (iii) those that inhibited attachment when administered simultaneously with the substratum (azide, dinitrophenol, chloramphenicol, puromycin, azauridine, rifampin, p-chloromercuribenzoate, and cephalothin). Cells killed by heating, Formalin, or mercuric chloride treatment were also less adhesive than viable cells. Collectively, these results indicate that (i) physiologically active cells are more adhesive than dead or physiologically impaired cells, (ii) impairment of cell wall synthesis by beta-lactam antibiotics renders cells less adhesive, and (iii) energy production and protein synthesis (including transcription) are both involved in some aspect of the adhesion process, whereas DNA synthesis is not.

Skeletal growth after oral administration of demineralized bone matrix.

Oral administration of bone extracts obtained from bovine demineralized bone matrix to rats has a direct effect on bone metabolism, affecting bone proportions and some markers of bone formation such as bone malate dehydrogenase, serum alkaline phosphatase and serum osteocalcin. Furthermore collagen deposition, bone protein synthesis and nucleic acids content were significantly increased by the treatment.