Correction of lipid peroxidation in stress with the peptide bioregulator thymopentin

Experiments on rats subjected to acute stress have revealed protective effect of thymopentin pentapeptide on somatic disorders and the state of the antioxidation system and the processes of lipid peroxidation in blood and brain.     

Fine structure of the conus papillaris in the bobtail goanna (Tiliqua rugosa)

The structure of the conus papillaris in an Australian lizard, the bobtail goanna (Tiliqua rugosa) was investigated by light and electron microscopy. In this strongly diurnal species, the conus papillaris consists of a heavily vascularized and pigmented, finger-like structure about 1 mm in diameter and 3-4 mm in length. It is situated over the optic nerve head and projects into the vitreous chamber. Within the conus are numerous capillaries and larger blood vessels, melanocytes and occasional mast cells. Many of the capillaries display prominent luminal and abluminal microfolds. Other capillaries show no microfolds while still others display an intermediate number of microfolds. The larger blood vessels are usually indistinguishable as to being either arterioles or venules. The endothelial cells of all blood vessels show a population of cytoplasmic granules. The melanocytes are large pleomorphic cells usually rich in microfilaments. Unmyelinated nerve processes are plentiful within the conus and the Schwann cells enclosing these nerve fibres are occasionally seen to be pigmented. The morphology of the conus papillaris indicates a heavy involvement in the transport of materials. It is considered to be homologous to the pecten oculi of the avian eye; to the falciform process of the teleost eye; to the supraretinal vessels of amphibians and to the intraretinal vessels of the mammalian eye.     

Defensive behaviour in the pond snail, Lymnaea stagnalis: the whole body withdrawal associated with exsanguination

The freshwater snail L. stagnalis is known to be able to respond to a strong, noxious stimulus with a full retraction of the foot and head into the shell accompanied with expelling the blood through the hemal pore. We have found that this behavioural response, besides graded local retractions, can be triggered by mild tactile stimulation provided that the stimulus is repeated several times. Only a complete exsanguination could be obtained, indicating that it is an all-or-none defensive behaviour. In an electrophysiological investigation of isolated brain, a number of similarities were found between this all-or-none behaviour and the so-called input 3 to central neurons, as described by Benjamin and Winlow. These include ability to be selectively activated by high calcium solutions, and blocked by keeping the snails in a spoiled water. Injection of snails with naloxone (0.5-2.0/micrograms/g) or ergotamine (0.4/microgram/g) blocked selectively the whole body withdrawal induced by tactile stimulation, but not that induced by injection of a high calcium saline or acetylcholine solution, indicating that enkephalinergic and/or dopaminergic mechanosensory neurons might be involved. The consideration of available data has led to a working hypothesis that the activity of input 3 might be the neurophysiological correlate of the high threshold all-or-none whole body withdrawal associated with exsanguination.     

Mathematical approach to modeling of the treatment of suppurative processes

Consideration of an inflammation focus as an "open system" provided analogy between microbiological processes in inflamed wounds and in systems of continuous cultivation of microorganisms. Mathematical modeling of such systems is widely used. Some of the methods for the mathematical modeling were applied to chemoprophylaxis and chemotherapy of postoperative wounds. In modeling continuous cultivation of microorganisms it is usually necessary to determine optimal conditions for the maximum yield of their biomass. In modeling of wound treatment the aim was to determine the process parameters providing the minimum biomass. The described simple models showed that there could be certain optimal flow rate of the washing fluid in the aspiration-washing procedure for wound treatment at which the drug was not completely washed out while the growth rate of the microbial population was minimal. Such mathematical models were shown valuable in optimizing the use of bactericidal and bacteriostatic antibiotics.     

A physical genome map of Pseudomonas aeruginosa PAO.

A complete macrorestriction map of the 5.9 Mb genome of Pseudomonas aeruginosa PAO (DSM 1707) was constructed by the combination of various one- and two-dimensional pulsed field gel electrophoresis techniques. A total of 51 restriction sites (36 SpeI sites, 15 DpnI sites) were placed on the physical map yielding an average resolution of 110 kb. Several genes encoding virulence factors and enzymes of metabolic pathways were located on the anonymous map by Southern hybridization. Distances between the gene loci were similar on the genetic and physical maps, suggesting an even distribution of genome mobility throughout the bacterial chromosome. The four rRNA operons were organized in pairs of inverted repeats. The two-dimensional macro-restriction techniques described herein are generally applicable for the genome mapping of any prokaryote and lower eukaryote which yields resolvable fragment patterns on two-dimensional pulsed field gels.     

Effect of recombinant human tumour necrosis factor alpha on protein synthesis in liver, skeletal muscle and skin of rats.

Bacterial endotoxins cause enhanced protein metabolism in liver, and protein catabolism in muscle and skin. These effects may be mediated by cytokines such as interleukin 1 (IL1) and tumour necrosis factor (TNF). The study investigates the timing and magnitude of effects of recombinant human TNF alpha on protein synthesis and protein and RNA content of the liver, tibialis muscle and skin of Wistar rats. Intravenous doses of 30 and 300 micrograms/kg of body weight were used and effects examined 8 h and 24 h after injection. Muscle protein content and synthetic rate were reduced at 8 h post-injection by over 18% and 20% respectively. Protein synthesis returned to normal after the lowest dose but remained depressed 24 h after the highest dose due to the accompanying anorexia. Opposite effects were observed in liver. Protein fractional synthetic rate (FSR) was increased by over 26% at 8 h post-injection and remained elevated 24 h after the higher but not lower dose of TNF. Total protein and RNA contents were significantly higher than controls at this time. Skin protein synthesis was unaffected by TNF; however an increase in protein and RNA content was observed at 8 h post-injection with the lower dose of TNF. Liver and muscle respond in a similar but more rapid way to TNF than to endotoxin. The response of skin is however totally different. While muscle may contribute amino acids for enhanced hepatic protein synthesis following exposure to TNF, skin does not.     

Translational reinitiation in the presence and absence of a Shine and Dalgarno sequence.

The process of translational reinitiation in Escherichia coli was studied in a two cistron system where expression of the downstream reporter gene was dependent on translation of an upstream reading frame. The dependence was almost absolute. Upstream translation increased expression of the downstream gene by two to three orders of magnitude. This large difference allowed us to quantitate restarts in a meaningful manner. In the absence of a Shine and Dalgarno (SD) region reinitiation occurred but its efficiency was about 10% of that found in the SD carrying counterpart. We discuss three ways by which translational coupling between neighboring cistrons can be enforced.     

Improved chemistry for oligodeoxyribonucleotide synthesis substantially improves restriction enzyme cleavage of a synthetic 35mer.

Two DNA duplexes of identical sequence and 35 nt in length were synthesized by an original and a highly improved version of phosphoramidite chemistry. By base composition analysis, DNA synthesized by improved chemistry (termed DMTS-imp) contained no detectable modified bases while DNA synthesized by the original chemistry (termed DMTS-std) had a large number of modifications. Under optimal reaction conditions, HhaI and RsaI cleaved the DMTS-std duplex to 76-77% completion and the DMTS-imp duplex to 96-99% completion. Restriction analysis and piperidine treatment yielded estimates of approximately 3.0% modified nucleotides in DMTS-std and approximately 1.0% in DMTS-imp. Overall, the improvements in chemistry increased the restriction efficiency of synthetic DNA up to 10-fold.     

Epstein-Barr virus episome-based promoter function in human myeloid cells.

Epstein-Barr virus (EBV) episomal replicons offer an expeditious means for amplifying transfected genes in human cells. A panel of EBV episomes was constructed to assess the relative utility of five distinct eukaryotic promoter elements for high level and inducible gene expression in stably transfected human myeloid leukemia cells. The Rous sarcoma virus 3' long terminal repeat (LTR) was most highly suited for EBV episome-based gene expression, whereas the lymphopapilloma virus and the SV40 early regulatory elements exhibited substantially lower activities. Chemically responsive promoter elements, such as the SV40 early, human metallothionein IIA and rat GRP78 gene promoters, retained their inducibility when EBV episome-based. Differences in gene expression obtained with the episomes reflected differential promoter activity rather than significant variations in episome copy numbers per cell. These observations provide guidelines for the optimal design of EBV episomal expression vectors for human expression work.