Dynamics of the count of bone marrow cells forming fibroblast colonies in culture and its relation to osteogenesis activity in the reparative regeneration of the lengthened limb

A comparative analysis of the number of bone marrow cells forming fibroblastic colonies in culture and of the roentgenological characteristics of bone regenerate during different periods of limb elongation was carried out in dogs. The increase in numbers of colony forming cells in the operated bone and decrease of their number in the intact ones were shown to correspond to the period of active osteogenesis. A distinct negative correlation between the number of colony forming cells in humerus and operated bone is considered as an indirect evidence of the migration of these cells from the intact bones. The number of colony forming cells can be used to estimate quantitatively the intensity of osteogenesis upon reparative regeneration under the conditions of limb elongation.     

Safety evaluation of nuclear polyhedrosis virus replication in pigs

To evaluate the hygienic risk involved in using baculoviruses for insect pest control, safety studies are required. Pigs were chosen as representative test animals of commercial and agricultural importance. The tests were aimed at detecting virus propagation, immune reactions, and signs of acute infection (changes in body temperature and hematology profile, swelling of lymph nodes). Four of five animals inoculated with nuclear polyhedrosis virus showed a slight temperature rise at day 2 postinfection. After day 4 postinfection, no differences between infected animals and controls were observed. In the bioassay, virus activity could be recovered from fecal samples; however, no activity was found in organ extracts. The data did not indicate hygienic risks involved in the application of nuclear polyhedrosis virus, especially that from Mamestra brassicae, in biological pest control.     

The differential sensitivity to a neurotigenic exposure of rat strains differing by the threshold of nervous system excitability]

The influence was studied of 15-days stressing on the appearance of stable neurosis-like state of rats lines, selected by the excitability of the nervous system. Unconditioned and conditioned components of behaviour were tested: pain sensitivity, behaviour in the open field, level of "anxiety", passive and active defensive avoidance. Differential reactivity was shown of the rats lines to prolonged stressing, depending on the genetically determined level of the nervous system functional state. Interlinear differences in dynamics of the development of neurosis-like state were established.     

Gramicidin channels: a new mechanism for transmembrane transfer of ions (from high resolution x-ray structural studies of the antibiotic)]

The crystal structure of the membrane-active antibiotic-cyclopeptide gramicidin S complex with urea was determined by the X-ray structure analysis. The gramicidin S molecule possesses an antiparallel beta-structure, its slightly twisted 30-membered cycle has a roughly rectangular form about 4.8 x 13.6 A in size, with the lesser side being formed by the main chain atoms of Phe and Pro residues. The maximum size of the molecule is 22.9 A. A characteristic feature of the molecule is the position of the extended side chains of the Orn residues on one side of the molecular cycle in the form of peculiar "legs--tentacles". One of these legs is "fastened" by the intramolecular H-bond to O atom of the nearer Phe4 residue, the other being free. The distance between the terminal NE atoms of the Orn residues is 5.7 A. The side chains of the Phe and Orn2 residues have trans-orientation, those of the Val, Orn7, Leu residues gauche-orientation. For Val1 and Leu3 side chains statistical disorder of the terminal C atoms is realized. The pyrrolidine rings of the Pro residues adopt Cs-C beta-exo conformation. There are one urea and 20 water molecules per one antibiotic molecule in the structure. The positions of three water molecules are fully occupied, the others with the probability of 0.56-0.20. One of the "water" positions is occupied on 2/3 by water, and on 1/3 by the O atom of the alcohol. There is a complicated system of intra- and intermolecular H-bonds in the structure, with and without the participation of water, alcohol and urea molecules. The gramicidin S molecules, collecting around 3(1) axis according to the left-handed double helix, form the channels whose outside hydrophobic surface is built of the side uncharged radicals, the inside surface being built of the main chain atoms, mainly of the O and N atoms and of the ornithine "tails" with uncharged NE atoms at the termini. The outer diameter of the channel is 29-43 A, inner (without ornithine "tails") is about 12.7 A. At the expense of the change of these "tails" conformation, the inner diameter of the channel filled with water molecules may change from 3.4 up to 6.3 A. Thus, the ions and particles of a rather large size may pass through the channel. The gramicidin channels are discovered and described for the first time. The channels in the crystal structure are close-packed under the hexagonal law.(ABSTRACT TRUNCATED AT 400 WORDS)     

Uptake of antitetanus F(ab')2 fragments into eukaryotic cells

1. In order to introduce antitetanus immunoglobulin fragments into eukaryotic cells, either antitetanus F(ab')2 or Fab' fragments have been linked to carrier molecules. Aciclovir, horseradish peroxidase, wheat germ agglutinin, and transferrin were tried as carriers. 2. F(ab')2-aciclovir and Fab'-horseradish peroxidase were not internalized by NG108-15 neurohybridoma cells. 3. [Fab']2-wheat germ agglutinin and F(ab')2-transferrin conjugates were internalized into various cells. 4. F(ab')2-transferrin conjugates were made with three different linkers: N-succinimidyl 3-(2-pyridyldithio) propionate, bis-maleimido hexane, and bis-maleimidoethoxy propane. All three conjugates were internalized but had a different fate inside the cells.     

Single-strand DNA triple-helix formation

Chemical modification studies provide evidence that single-stranded oligodeoxyribonucleotides can form stable intrastrand triple helices. Two oligonucleotides of opposite polarity were synthesized, each composed of a homopurine-homopyrimidine hairpin stem linked to a pyrimidine sequence which is capable of folding back on the hairpin stem and forming specific Hoogsteen hydrogen bonds. Using potassium permanganate as a chemical modification reagent, we have found that two oligodeoxyribonucleotides of sequence composition type 5'-(purine)8(N)4(pyrimidine)8(N)6(pyrimidine)8-3' and 5'-(pyrimidine)8N6(pyrimidine)8N4(purine)8-3' undergo dramatic structural changes consistent with intrastrand DNA triple-helix formation induced by lowering the pH or raising the Mg2+ concentration. The intrastrand DNA triple helix is sensitive to base mismatches.     

Parasitic fungi from the province of Manisa

This paper is a study of the parasitic fungi of Manisa. 32 species of parasitic fungi have been discovered of which 2 species are new for the Turkish parasitic fungal flora. Also, new hosts for 13 of these species are reported in Turkey for the first time.     

Identification of two nuclear polyhedrosis viruses from the cabbage moth, Mamestra brassicae (Lepidoptera: Noctuidae)

Two nuclear polyhedrosis viruses from the cabbage moth Mamestra brassicae found in two geographical areas in Europe have been characterized and compared. These two virus isolates have similar biological activities and have the same host range. The two M. brassicae nuclear polyhedrosis viruses can be distinguished by restriction endonuclease analysis of their DNA. They appear to be distinct but related virus strains.     

Preparation of androsta-1,4-diene-3,17-dione from sterols using Mycobacterium neoaurum VKPM As-1656 strain

A product of microbiological cleavage of the sterols side chain, androsta-1,4-diene-3,17-dione, is toxic for bacteria, in particular, actinobacteria of the genera Mycobacterium and Arthrobacter. Sterols were transformed into androsta-1,4-diene-3,17-dione by culturing the M. neoaurum VKPM An-1656 strain in a high yield, provided that a sorbent was used for elimination of contact between the bacterial cells and the product. Unlike the cholesterol side chain, the more branched chains of phytosterols were cleaved in the presence of M. neoaurum at a high rate only under turbulent stirring of the culture medium, which intensified the formation of hydrocarbonate ion from NaNI3 in situ.