The human papillomavirus 16 E6 protein binds to tumor necrosis factor (TNF) R1 and protects cells from TNF-induced apoptosis

High risk strains of human papillomavirus (HPV), such as HPV 16, cause human cervical carcinoma. The E6 protein of HPV 16 mediates the rapid degradation of p53, although this is not the only function of E6 and cannot completely explain its transforming potential. Previous work in our laboratory has demonstrated that transfection of HPV 16 E6 into the tumor necrosis factor (TNF)-sensitive LM cell line protects expressing cells from TNF-induced apoptosis in a p53-independent manner, and the purpose of this study was to determine the molecular mechanism underlying this protection. Caspase 3 and caspase 8 activation were significantly reduced in E6-expressing cells, indicating that E6 acts early in the TNF apoptotic pathway. In fact, E6 binds directly to TNF R1, as shown both by co-immunoprecipitation and mammalian two-hybrid approaches. E6 requires the same C-terminal portion of TNF R1 for binding as does TNF R1-associated death domain, and TNF R1/TNF R1-associated death domain interactions are decreased in the presence of E6. HA-E6 also blocked cell death triggered by transfection of the death domain of TNF R1. Together, these results provide strong support for a model in which HPV E6 binding to TNF R1 interferes with formation of the death-inducing signaling complex and thus with transduction of proapoptotic signals. They also demonstrate that HPV, like several other viruses, has developed a method for evading the TNF-mediated host immune response.     

The intraspecific differentiation of the burrow tick Ixodes crenulatus (Ixodidae)

In four extensive disjunct areas of the distribution range of Ixodes crenulatus Koch, 1844 complexes of samples in 8 locations, and separate samples in two locations have been studied (fig.). Morphological characters (sizes of organs of idiosome, gnathostoma, legs, as well as some proportions of organs), which show statistically significant differences between complexes of samples on all corresponding stages of ontogenesis were revealed (tabl. 1, 2). Statistically significant differences were determined by Student's criterion (table. 3, 4). We use the term "transit" characters to denote these characters if they have to addition a similar tendency at all stages of ontogenesis. Complexes of samples showing statistically significant differences of transit characters are considered by us as morphotypes. Apparently these differences of morphotypes were formed evolutionally. In European disjunct area morphotypes divided into two groups on the basis of the degree of differences: western (A, B), and eastern (C, D, E). Degree of differences of morphotypes within each group is low, whereas one between of these two groups is high and corresponds to differences of morphotypes A, B from all Asian morphotypes (F, G, H, I, J), and of morphotypes C, D, E from Asian ones in mountain disjunct areas I. crenulatus (G, H, I, J). At the same time Eastern-European complex of morphotypes (C, D, E) is morphologically similar to the morphotype from north Kazakhstan disjunct area (F). All Asian morphotypes have high degree of differences one from the other. Species of the genus Marmota are initial hosts of I. crenulatus, they retain the main role as hosts in Eastern-European and Asian morphotypes: C, D, E, F--M. bobac bobac (Muller, 1776), G--M. baibacina centralis (Thomas, 1909), I, J--M. sibirica sibirica (Radde, 1862). The most aberrant in all characters morphotypes are the ones inhabiting European areas (A, B), where marmots are exterminated. These morphotypes parasitize on hibernating carnivores.     

Endospore formation by Streptomyces avermitilis in submerged culture

The capability of streptomycetes to form endospores during their life cycle was studied in submerged cultures of Streptomyces avermitilis. Submerged S. avermitilis spores were most intensely formed (1) during the culture development cycles on synthetic medium CP1 with glucose under phosphate limitation, and (2) in autolysing cell suspensions of high density obtained by tenfold concentration of a stationary-phase culture grown in a synthetic medium resuspended in phosphate buffer (pH 7.2) with 0.2% CaCl2. Endospores of S. avermitilis formed in submerged cultures shared the major characteristics of specialized microbial resting forms: heat resistance, resistance to lysozyme, ability to pertain to the main species-defining features, and ultrastructural organization characteristic of endospores. They can be considered a resting form of streptomycetes alternative to the spores formed exogenously on aerial mycelium in a surface culture.     

Effects of plasmid DNA injection on cyclophosphamide-accelerated diabetes in NOD mice

Type 1 diabetes results in most cases from the destruction of insulin-secreting beta cells by the immune system. Several immunization methods based on administration of autoantigenic polypeptides such as insulin and glutamic acid decarboxylase (GAD) have been used to prevent autoimmune diabetes in the non-obese diabetic (NOD) mouse. In the work presented here, a gene-based approach was taken for a similar purpose. A plasmid carrying different cDNAs was used to investigate the effects of injecting naked DNA on cyclophosphamide-accelerated diabetes in female NOD mice. Four-week-old animals received intramuscular injections of plasmid DNA encoding either intracellular GAD, a secreted form of GAD, or a secreted form of a soft coral luciferase. Monitoring of glycosuria and hyperglycemia indicated that injection of plasmid DNA encoding secreted GAD and secreted luciferase could prevent and delay diabetes, respectively. In contrast, injection of DNA encoding intracellular GAD did not suppress the disease significantly. Analysis of anti-GAD IgG(1) antibody titers in animal sera indicated that diabetes prevention after injection of GAD-encoding DNA was possibly associated with increased Th2-type activity. These results suggest that cellular localization of GAD is a factor to consider in the design of GAD-based genetic vaccines for the prevention of autoimmune diabetes.     

Biochemical mechanisms of realization of antiviral and interferon-inducing activity of amixine and its analogs

Antiviral and interferon inducing activity of the amixine and its some derivatives, as well as their influence on the proteolytic enzymes activity, monooxygenase activity of the microsomal fraction, level of the lipids peroxidation were studied. Lack of correlation between antiviral and interferon inducing activity in the investigated series of compounds was found. Vice versa, the good correlation between interferon inducing activity and the elastase-like activities inhibition ability of the compounds was observed. It allows to state the assumption, that only one ability of compounds to induce of an interferon doesn't suffice for obtaining of high titres of interferon, and while their rather high antiproteolitic activity is necessary. It's shown, that except for one compound the influence of amixine and its derivatives on the red-ox enzymes activity well correlates with their ability to the interferon-inducing. All presented above allows to attribute amixine and its derivatives to polymodal antiviral agents.     

Radioprotective action of GHM-10 when administered with dextran sulfate and heparin

A single administration of dextransulfate (40 mg/kg, 1-3 days before irradiation), or a double injection of heparin (250 units/kg, 24 hr and 15 min before irradiation) potentiated a weak radioprotective effect of gas hypoxic mixture (GHM-10) on animals exposed to absolutely lethal doses.     

Isolation and properties of human immunoglobulin-peroxidase complex]

The complexes of human immunoglobulin G (IgG) with peroxidase produced by a two-step synthesis using glutaraldehyde retain high enzymatic and immunochemical activities. The effectiveness of the complex formation depends on the concentration of glutaraldehyde used for enzyme modification. Optimal molar ratios of the constituent components during the synthesis of the complex and localization of the enzyme on the IgG molecule are discussed. Preliminary heating of IgG or the overall complex at 50 degrees C results in an increase of the complex stability (20-fold) under storage.