The impact of a boosting immunogen on the differentiation of secondary memory CD8+ T cells

While recent studies have demonstrated that secondary CD8⁺ T cells develop into effector-memory cells, the impact of particular vaccine regimens on the elicitation of these cells remains poorly defined. In the present study we evaluated the effect of three different immunogens—recombinant vaccinia, recombinant adenovirus, and plasmid DNA—on the generation of memory cellular immune responses. We found that vectors that induce the rapid movement of CD8⁺ T cells into the memory compartment during a primary immune response also drive a rapid differentiation of these cells into effector-memory CD8⁺ T cells following a secondary immunization. In contrast, the functional profiles of both CD8⁺ and CD4⁺ T cells, assessed by measuring antigen-stimulated gamma interferon and interleukin-2 production, were not predominantly shaped by the boosting immunogen. We also demonstrated that the in vivo expression of antigen by recombinant vectors was brief following boosting immunization, suggesting that antigen persistence has a minimal impact on the differentiation of secondary CD8⁺ T cells. When used in heterologous or in homologous prime-boost combinations, these three vectors generated antigen-specific CD8⁺ T cells with different phenotypic profiles. Expression of the memory-associated molecule CD27 on effector CD8⁺ T cells decreased following heterologous but not homologous boosting, resulting in a phenotypic profile similar to that seen on primary CD8⁺ T cells. These data therefore suggest that the phenotype of secondary CD8⁺ T cells is determined predominantly by the boosting immunogen whereas the cytokine profile of these cells is shaped by both the priming and boosting immunogens.     

E-LDL upregulates TOSO expression and enhances the survival of human macrophages

Uptake of modified lipoproteins by macrophages causes foam cell formation and promotes atherosclerosis. Atherogenic lipoproteins are cytotoxic and induce cell death under certain conditions but may also enhance macrophage survival. Macrophages treated with enzymatically modified LDL (E-LDL) were subjected to GeneChip analysis and the antiapoptotic gene TOSO was found induced. TOSO mRNA is upregulated and apoptosis is reduced in E-LDL but not in oxidized LDL (Ox-LDL) loaded macrophages. FLIP(L) abundance was suggested to mediate the antiapoptotic properties of TOSO; however, FLIP(L) was not changed. Ox-LDL is internalized predominantly by scavenger receptors such as CD36 while E-LDL particles are preferentially internalized by Fc- and complement-receptor dependent phagocytosis and internalization of phagobeads by macrophages upregulates TOSO. In COS-7 cells however, phagocytotic activity was not affected by TOSO. These data indicate that E-LDL-generated foam cells are protected from cell death most likely through the expression of TOSO by a FLIP(L) independent mechanism.     

Abandoning aggression but maintaining self-nonself discrimination as a first stage in ant supercolony formation

An ant supercolony is a very large entity with very many queens. Although normal colonies of small extent and few queens remain distinct, a supercolony is integrated harmoniously over a large area [1, 2]. The lack of aggression is advantageous: Aggression is costly, involving direct and indirect losses and recognition errors [3, 4]. Indeed, supercolonial ants are among the ecologically most successful organisms [5-7]. But how supercolonies arise remains mysterious [1, 2, 8]. Suggestions include that reduced within-colony relatedness or reduced self-nonself discrimination would foster supercolony formation [1, 2, 5, 7, 9-12]. However, one risks confusing correlation and causality in deducing the evolution from distinct colonies to supercolonies when observing established supercolonies. It might help to follow up observations of another lack of aggression, that between single-queened colonies in some ant species. We show that the single-queened Lasius austriacus lacks aggression between colonies and occasionally integrates workers across colonies but maintains high within-colony relatedness and self-nonself discrimination. Provided that the ecological framework permits, reduced aggression might prove adaptive for any ant colony irrespective of within-colony relatedness. Abandoning aggression while maintaining discrimination might be a first stage in supercolony formation. This adds to the emphasis of ecology as central to the evolution of cooperation in general [13].     

N9-benzyl-substituted 1,3-dimethyl- and 1,3-dipropyl-pyrimido[2,1-f]purinediones: synthesis and structure-activity relationships at adenosine A1 and A2A receptors

Synthesis and physicochemical properties of N-benzyl pyrimido[2,1-f]purinediones are described. These derivatives were synthesized by the cyclization of 7-chloropropylo-8-bromo-1,3-dimethyl- or 1,3-dipropyl xanthine derivatives with corresponding (un)substituted benzylamines. Dipropyl derivatives were obtained under microwave irradiation conditions either. The obtained compounds (1-20) were evaluated for their affinity to adenosine A1 and A2A receptors, selected compounds were additionally investigated for affinity to the A3 receptor subtype. The results of the radioligand binding assays to A1 and A2A adenosine receptors showed that most of the 1,3-dimethyl-9-benzylpyrimidopurinediones exhibited selective affinity to A2A receptors at micromolar or submicromolar concentrations (for example, derivative 9 with o-methoxy substituent displayed a Ki value of 0.699 microM at rat A2A receptor with more than 36-fold selectivity). Contrary to previously described arylpyrimido[2,1-f]purinediones dipropyl derivatives (compounds 15-20) showed affinity to both kinds of receptors increased, however A1 affinity increased to a larger extent, with the result that A2A selectivity was abolished. The best adenosine A1 receptor ligand was m-chlorobenzyl derivative 18 (Ki=0.089 microM and 5-fold A1 selectivity). Structure-activity relationships were discussed with the analysis of lipophilic and spatial properties of the investigated compounds. Pharmacophore model of adenosine A1 receptor antagonist was adopted for this purpose.     

Phylogenetic distribution of catalase-peroxidases: are there patches of order in chaos?

Hydrogen peroxide features in many biological oxidative processes and must be continuously degraded enzymatically either via a catalatic or a peroxidatic mechanism. For this purpose ancestral bacteria evolved a battery of different heme and non-heme enzymes, among which heme-containing catalase-peroxidases (CP) are one of the most widespread representatives. They are unique since they can follow both H(2)O(2)-degrading mechanisms, the catalase activity being clearly dominant. With the fast increasing amount of genomic data available, we were able to perform an extensive search for CP and found almost 300 sequences covering a large range of microorganisms. Most of them were encoded by bacterial genomes, but we could also find some in eukaryotic organisms other than fungi, which has never been shown until now. Our screen also reveals that approximately 60% of the bacteria do not possess CP genes. Chaotic distribution among species and incongruous phylogenetic reconstruction indicated existence of numerous lateral gene transfers in addition to duplication events and regular speciation. The results obtained show an impressively complex gene transmission pattern, and give some new insights about the role of CP and the origin of life on earth. Finally, we propose for the first time bacterial candidates that may have participated in the transfer of CP from bacteria to eukaryotes.     

Dual target strategy: combining distinct non‐dopaminergic treatments reduces neuronal cell loss and synergistically modulates l‐DOPA‐induced rotational behavior in a rodent model of Parkinson's disease

The glutamate metabotropic receptor 5 (mGluR5) and the adenosine A_2A receptor (A_2AR) represent major non‐dopaminergic therapeutic targets in Parkinson's disease (PD) to improve motor symptoms and slow down/revert disease progression. The 6‐hydroxydopamine rat model of PD was used to determine/compare the neuroprotective and behavioral impacts of single and combined administration of one mGluR5 antagonist, 2‐methyl‐6‐(phenylethynyl)pyridine (MPEP), and two A_2AR antagonists, (E)‐phosphoric acid mono‐[3‐[8‐[2‐(3‐methoxyphenyl)vinyl]‐7‐methyl‐2,6‐dioxo‐1‐prop‐2‐ynyl‐1,2,6,7‐tetrahydropurin‐3‐yl]propyl] (MSX‐3) and 8‐ethoxy‐9‐ethyladenine (ANR 94). Chronic treatment with MPEP or MSX‐3 alone, but not with ANR 94, reduced the toxin‐induced loss of dopaminergic neurons in the substantia nigra pars compacta. Combining MSX‐3 and MPEP further improved the neuroprotective effect of either antagonists. At the behavioral level, ANR 94 and MSX‐3 given alone significantly potentiated l ‐DOPA‐induced turning behavior. Combination of either A_2AR antagonists with MPEP synergistically increased L‐DOPA‐induced turning. This effect was dose‐dependent and required subthreshold drug concentration, which per se had no motor stimulating effect. Our findings suggest that co‐treatment with A_2AR and mGluR5 antagonists provides better therapeutic benefits than those produced by either drug alone. Our study sheds some light on the efficacy and advantages of combined non‐dopaminergic PD treatment using low drug concentration and establishes the basis for in‐depth studies to identify optimal doses at which these drugs reach highest efficacy.

     

Advancing the surgical implantation of electronic tags in fish: a gap analysis and research agenda based on a review of trends in intracoelomic tagging effects studies

Early approaches to surgical implantation of electronic tags in fish were often through trial and error, however, in recent years there has been an interest in using scientific research to identify techniques and procedures that improve the outcome of surgical procedures and determine the effects of tagging on individuals. Here we summarize the trends in 108 peer-reviewed electronic tagging effect studies focused on intracoleomic implantation to determine opportunities for future research. To date, almost all of the studies have been conducted in freshwater, typically in laboratory environments, and have focused on biotelemetry devices. The majority of studies have focused on salmonids, cyprinids, ictalurids and centrarchids, with a regional bias towards North America, Europe and Australia. Most studies have focused on determining whether there is a negative effect of tagging relative to control fish, with proportionally fewer that have contrasted different aspects of the surgical procedure (e.g., methods of sterilization, incision location, wound closure material) that could advance the discipline. Many of these studies included routine endpoints such as mortality, growth, healing and tag retention, with fewer addressing sublethal measures such as swimming ability, predator avoidance, physiological costs, or fitness. Continued research is needed to further elevate the practice of electronic tag implantation in fish in order to ensure that the data generated are relevant to untagged conspecifics (i.e., no long-term behavioural or physiological consequences) and the surgical procedure does not impair the health and welfare status of the tagged fish. To that end, we advocate for (1) rigorous controlled manipulations based on statistical designs that have adequate power, account for inter-individual variation, and include controls and shams, (2) studies that transcend the laboratory and the field with more studies in marine waters, (3) incorporation of knowledge and techniques emerging from the medical and veterinary disciplines, (4) addressing all components of the surgical event, (5) comparative studies that evaluate the same surgical techniques on multiple species and in different environments, (6) consideration of how biotic factors (e.g., sex, age, size) influence tagging outcomes, and (7) studies that cover a range of endpoints over ecologically relevant time periods.     

A review of tricaine methanesulfonate for anesthesia of fish

Tricaine methanesulfonate (TMS) is an anesthetic that is approved for provisional use in some jurisdictions such as the United States, Canada, and the United Kingdom (UK). Many hatcheries and research studies use TMS to immobilize fish for marking or transport and to suppress sensory systems during invasive procedures. Improper TMS use can decrease fish viability, distort physiological data, or result in mortalities. Because animals may be anesthetized by junior staff or students who may have little experience in fish anesthesia, training in the proper use of TMS may decrease variability in recovery, experimental results and increase fish survival. This document acts as a primer on the use of TMS for anesthetizing juvenile salmonids, with an emphasis on its use in surgical applications. Within, we briefly describe many aspects of TMS including the legal uses for TMS, and what is currently known about the proper storage and preparation of the anesthetic. We outline methods and precautions for administration and changes in fish behavior during progressively deeper anesthesia and discuss the physiological effects of TMS and its potential for compromising fish health. Despite the challenges of working with TMS, it is currently one of the few legal options available in the USA and in other countries until other anesthetics are approved and is an important tool for the intracoelomic implantation of electronic tags in fish.     

Pyridyl amides as potent inhibitors of T-type calcium channels

A novel series of amide T-type calcium channel antagonists were prepared and evaluated using in vitro and in vivo assays. Optimization of the screening hit 3 led to identification of the potent and selective T-type antagonist 37 that displayed in vivo efficacy in rodent models of epilepsy and sleep.