Cell-surface changes during mitogenic stimulation of lymphocytes assessed by the binding of wheat-germ agglutinin and other plant lectins

Lymphocytes from murine lymph node, cultured in the presence of an optimally mitogenic dose of phytohaemagglutinin, were stained with fluoresceinated lectins and analysed by flow cytometry. A marked increase in the ability of lymphocytes to bind wheat-germ agglutinin was observed that is particularly pronounced for the blast cells, reaching a maximum at about 40 h, when they are 5.5-times brighter than cells at zero time. The corresponding intensification of the small cells is 2-fold. Much smaller increases in binding accompanying blast transformation were observed when fluoresceinated concanavalin A or Lens culinaris haemagglutinin were used. Polyacrylamide gel electrophoresis of plasma membranes followed by treatment of the gels with radioactively labelled lectins and autoradiography also showed a very distinct increase in the binding of wheat-germ agglutinin to membranes from mitogen-stimulated porcine lymphocytes. Less marked changes in the binding of concanavalin A Lens culinaris heamagglutin and Ricinus communis agglutinin 120 were also noted. The apparent multiplicity of glycoproteins that bind each lectin, suggests that in each case the sites are heterogeneous. We conclude that lymphocytes stimulated by the T-cell mitogen phytohaemagglutinin expose new glycoprotein receptors for wheat-germ agglutinin that are most abundant on blast cells at 40 h. Attempts to characterize the receptor biochemically suggest that the carbohydrate moiety recognised by wheat-germ agglutinin is present on a glycoprotein of approx. 120 kDa molecular mass and also possibly on glycoproteins of 170–190 kDa.     

Chloroplast DNA variation and population structure in the widespread forest tree, Eucalyptus grandis

Recognition of genetic structure of populations and the ability to identify vulnerable populations is useful for the formation of conservation management strategies for plants. Eucalyptus grandis is a tall forest tree that has a major area of occurrence in subtropical eastern Australia, with smaller populations located in the east coast tropics. Many widespread forest species exhibit population differentiation that corresponds to geographic regions. However, Eucalyptus grandis appears to be an exception based on isozyme and morphological data. This is intriguing given a large discontinuity between northern populations and those in the southern part of the species range. In this study, the distribution of a maternally inherited chloroplast locus was examined because it was more likely to reveal genetic structure due to the slower evolution of the chloroplast genome and limited dispersal of seed in eucalypts. As expected, the G _ST for chloroplast DNA was higher than that for nuclear DNA but indicated low population differentiation for a forest tree species. Phylogeographic analysis indicated that the 15 populations grouped into three broad geographical regions; however, overall population structure was weak suggesting that the large geographical disjunction in the distribution of E. grandis may be relatively recent. A paradigm for conservation management of E. grandis based on chloroplast DNA haplotype distribution would take into account the low differentiation among populations.     

Quinolines as a novel structural class of potent and selective PDE4 inhibitors. Optimisation for inhaled administration

Crystallography driven optimisation of a lead derived from similarity searching of the GSK compound collection resulted in the discovery of quinoline-3-carboxamides as highly potent and selective inhibitors of phosphodiesterase 4B. This series has been optimized to GSK256066, a potent PDE4B inhibitor which also inhibits LPS induced production of TNF-α from isolated human peripheral blood mononuclear cells with a pIC₅₀ of 11.1. GSK256066 also has a suitable profile for inhaled dosing.     

Assessment of therapeutic responses to gametocytocidal drugs in Plasmodium falciparum malaria

Background

Effective mating between laboratory-reared males and wild females is paramount to the success of vector control strategies aiming to decrease disease transmission via the release of sterile or genetically modified male mosquitoes. However mosquito colonization and laboratory maintenance have the potential to negatively affect male genotypic and phenotypic quality through inbreeding and selection, which in turn can decrease male mating competitiveness in the field. To date, very little is known about the impact of those evolutionary forces on the reproductive biology of mosquito colonies and how they ultimately affect male reproductive fitness.

Methods

Here several male reproductive physiological traits likely to be affected by inbreeding and selection following colonization and laboratory rearing were examined. Sperm length, and accessory gland and testes size were compared in male progeny from field-collected females and laboratory strains of Anopheles gambiae sensu stricto colonized from one to over 25 years ago. These traits were also compared in the parental and sequentially derived, genetically modified strains produced using a two-phase genetic transformation system. Finally, genetic crosses were performed between strains in order to distinguish the effects of inbreeding and selection on reproductive traits.

Results

Sperm length was found to steadily decrease with the age of mosquito colonies but was recovered in refreshed strains and crosses between inbred strains therefore incriminating inbreeding costs. In contrast, testes size progressively increased with colony age, whilst accessory gland size quickly decreased in males from colonies of all ages. The lack of heterosis in response to crossing and strain refreshing in the latter two reproductive traits suggests selection for insectary conditions.

Conclusions

These results show that inbreeding and selection differentially affect reproductive traits in laboratory strains overtime and that heterotic ‘supermales’ could be used to rescue some male reproductive characteristics. Further experiments are needed to establish the exact relationship between sperm length, accessory gland and testes size, and male reproductive success in the laboratory and field settings.     

Double-blind comparison of absorbable colloidal bismuth subcitrate and nonabsorbable bismuth subnitrate in the eradication of Helicobacter pylori and the relief of nonulcer dyspepsia

Background. Bismuth is widely used for the eradication of H. pylori , especially in developing countries, although there are concerns over its neurotoxicity. Whether bismuth has to be absorbed in humans to act against H. pylori is not known. In this study, we compared "absorbable" (colloidal bismuth subcitrate) and "nonabsorbable" (bismuth subnitrate) bismuth as part of triple therapy in the eradication of H. pylori.
Materials and Methods. A double-blind, randomized, placebo-controlled trial was carried out with 120 H. pylori –positive patients with nonulcer dyspepsia. Group CBS + Ab (n = 35) received colloidal bismuth subcitrate (one tablet qds), amoxicillin (500 mg qds), and metronidazole (400 mg tds). Group BSN + Ab (n = 35) received bismuth subnitrate (two tablets tds) and the same antibiotics. Group Ab (n = 35) received placebo bismuth (two tablets tds) and the antibiotics. Group BSN (n = 15) received bismuth subnitrate (two tablets tds) and placebo antibiotics. Bismuth was taken for 4 weeks and the antibiotics for the first 2 weeks. H. pylori eradication, side effects, compliance, pre- and post-treatment symptom scores, and bismuth absorption were assessed.
Results. H. pylori eradication was 69%, 83%, 31%, and 0% in CBS + Ab, BSN + Ab, Ab, and BSN, respectively. Side effects, compliance, and symptom relief were similar in all groups, but blood bismuth levels were significantly greater in CBS + Ab than the other three groups.
Conclusion. The efficacy of bismuth-based therapies as part of triple therapy in the eradication of H. pylori is unrelated to absorption. Hence, the use of effective but poorly absorbed bismuth preparations should be encouraged for bismuth-based eradication therapies.